Stefan Koch
Bogazici University, Management, Faculty Member
OpenACS is a high level community framework designed for developing collaborative Internet sites. It started from a university project at MIT, got momentum from the ArsDigita Foundation, and split up into a commercial and an open... more
OpenACS is a high level community framework designed for developing collaborative Internet sites. It started from a university project at MIT, got momentum from the ArsDigita Foundation, and split up into a commercial and an open source version. OpenACS has proven its durability and utility by surviving the death of its parent company (ArsDigita) to grow into a vibrant grassroots collection of independent consultants and small companies implementing diverse and complex Web solutions around the globe for NPOs, philanthropy, and profit. A heritage from this history is a still dominant position of contributors with commercial interests, which in its intensity is above the norm found in open source projects. In this paper, OpenACS with its community is presented as a case study documenting the forces between commercial interests, securing investments, and technical development in a large open source project with a large proportion of commercial involvement.
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The use of ICT in the Austrian judicial system can be described as widespread. Currently, a plethora of different benchmarking studies have been published ranking different countries according to their e-government readiness or maturity,... more
The use of ICT in the Austrian judicial system can be described as widespread. Currently, a plethora of different benchmarking studies have been published ranking different countries according to their e-government readiness or maturity, but they are inconclusive, so no results are given here. For discussion of these studies, see for example Lee, Tan and Trimi (2005) or Ostermann and Staudinger (2005). An overview of the technologies in use, which also covers the general organisation of the judicial system in Austria, can be found in ...
Research Interests: Immunology and Immunity
ABSTRACT Motivated by information technology evaluation problems identified in a large public sector organization, we propose how evaluation requirements can be supported by a framework combining different models andmethods from... more
ABSTRACT Motivated by information technology evaluation problems identified in a large public sector organization, we propose how evaluation requirements can be supported by a framework combining different models andmethods from information systems evaluation theory. The article extends the content, context, process perspectives of organizational change with operations research techniques and demonstrates the approach in practice for an Enterprise Resource Planning evaluation.
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Research Interests: Biopsy, Humans, Intestinal Mucosa, Ulcerative colitis, Female, and 19 moreMale, Bacteria, Clinical Sciences, Colitis, Middle Aged, Spectrum, Fluorescent in situ hybridization, Adult, Feces, Gut, Mucus, Abdominal Surgery, Bacterial translocation, Appendix, Acute Appendicitis, Alcian blue, ENEMA, Inflammatory response, and Acute Disease
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Research Interests: Microbiology, Biomass, Stress, Industrial Biotechnology, Food Microbiology, and 16 moreFood Preservation, Salt, Resistance, Bacteria, Yield, Temperature, Osmotic pressure, Freeze Drying, Food Sciences, Osmotic Stress, Optimal Growth, Salts, Hydrogen-Ion Concentration, Lyophilisation, Optical Density, and pH control
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Research Interests: Cancer, Wound Healing, Cell Adhesion, Regulation, Immunohistochemistry, and 15 moreConfocal Microscopy, Western blotting, Signal Transduction, Cercopithecus aethiops, Humans, Muscle, Intestinal Mucosa, Collagen, Animals, Myosin, American, Fluorescent Antibody Technique, Digestive System, Proteoglycans, and Laminin
ABSTRACT Die Symptomatik einer Depression ist durch reduzierte emotionale Schwingungsfähigkeit, negative Kognitionen, sozialen Rückzug und negatives Selbstwerterleben charakterisiert. Es wird eine erhöhte Reaktivität auf negative Stimuli... more
ABSTRACT Die Symptomatik einer Depression ist durch reduzierte emotionale Schwingungsfähigkeit, negative Kognitionen, sozialen Rückzug und negatives Selbstwerterleben charakterisiert. Es wird eine erhöhte Reaktivität auf negative Stimuli (negative potentiation) bzw. eine reduzierte Sensitivität auf den emotionalen Kontext (emotion context insensitivity) angenommen (z.B. Peeters et al., 2010). Ziel dieser Studie ist die Untersuchung der Stabilität bzw. Instabilität von Affekt und Selbstwerterleben bei Depression mittels Ambulantes Assessment im Kontext der stationären psychotherapeutischen Behandlung. Geplant ist die Rekrutierung von 50 Patientinnen der Schön-Klinik Roseneck (Prien am Chiemsee) mit mindestens mittelgradiger depressiver Episode (ICD-10 F32.1/.2 bzw. F33.1/.2), welche über einen viertägigen Zeitraum mit elektronischen Tagebüchern ausge-stattet werden. Dabei werden mehrfach täglich in Alltagssituationen das Selbstwerterleben mit einer Kurzform der Rosenberg Self Esteem Scale (SES) und die momentane Stimmung mit einer Kurzform des Mehrdimensionalen Befindlichkeitsfragebogens (MDBF) erfasst. Als Vergleichsgruppen dienen bereits vorliegende Daten von 46 Patientinnen mit Borderline-Persönlichkeitsstörung (ZI Mannheim) und 57 gesunden Kontrollen (KIT Karlsruhe). Es werden das laufende Projekt und erste Ergebnisse vorgestellt. Ambulantes Assessment bieten wesentliche Vorteile gegenüber möglicherweise bei der Un-tersuchung von Depressionen besonders relevanten Verzerrungen retrospektiver Selbstein-schätzungen (Ebner-Priemer & Trull, 2009; 2013). Neben der Untersuchung zentraler auf-rechterhaltender Faktoren der Depression erlaubt die vorliegende Studie die Erprobung von Ambulantem Assessment unter stationären Routinebedingungen.
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This article strives to support research and practice in the application of decision and valuation models to IT infrastructure projects in public administration. The aim is to present the elements needed to flexibly embrace evaluation... more
This article strives to support research and practice in the application of decision and valuation models to IT infrastructure projects in public administration. The aim is to present the elements needed to flexibly embrace evaluation structure, management and quantification methods. We sketch how different models can work together in a complementary way laying a robust and comprehensive foundation for an integrated analysis of IT impacts. We present design and assessment results from two major IT ...
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This study addresses the complex relationship between decision making for ERP investments and the consideration of organizational impact under 2 different perspectives: Enterprise Resource Planning (ERP) system decisions in organizations... more
This study addresses the complex relationship between decision making for ERP investments and the consideration of organizational impact under 2 different perspectives: Enterprise Resource Planning (ERP) system decisions in organizations with Business Process Improvement (BPI) in particular Business Process Reengineering (BPR) efforts and ERP decisions without BPI/BPR efforts. On the basis of a questionnaire sent to 813 austrian middle und large scale organizations, this paper shows that companies have weighted the ...
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The distally based rectus abdominis myocutaneous flap is used in a new technique for vaginal reconstruction after pelvic exenteration for malignant disease. We identified 27 patients who underwent this procedure, of whom eight had a total... more
The distally based rectus abdominis myocutaneous flap is used in a new technique for vaginal reconstruction after pelvic exenteration for malignant disease. We identified 27 patients who underwent this procedure, of whom eight had a total of 14 postoperative CT scans and two CT-directed biopsies. The myocutaneous flap appeared as a unilateral arcuate band of soft tissue extending from the linea alba to the rectal fascia or sacrum. Additional CT findings included asymmetric thinning of the ventral abdominal wall (7/8), fluid collections (2/8), vaginal breakdown (1/8), presacral soft-tissue thickening (6/8), and tumor recurrence (3/8). The postoperative CT scan reflects the altered anatomy produced by the surgery. Complications and recurrent disease can be recognized as deviations from the normal postoperative appearance.
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This paper presents first results from research intoopen source projects from a software engineering perspective. The research methodology employed relies on public dataretrieved from the CVS-repository of the GNOME project andrelevant... more
This paper presents first results from research intoopen source projects from a software engineering perspective. The research methodology employed relies on public dataretrieved from the CVS-repository of the GNOME project andrelevant discussion groups. This methodology is described indetail and some of the results concerning the specialcharacteristics of open source software development are given. I.
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The purpose of the study was to assess the incidence and prognostic role of epithelial-to-mesenchymal-transition (EMT) in squamous cell carcinoma of the penis (SCCP). Sixty tumor specimens of surgically treated SCCP patients characterized... more
The purpose of the study was to assess the incidence and prognostic role of epithelial-to-mesenchymal-transition (EMT) in squamous cell carcinoma of the penis (SCCP). Sixty tumor specimens of surgically treated SCCP patients characterized by a central histopathologic review were stained with antibodies against E-cadherin, N-cadherin, β-catenin, and vimentin. Staining profiles were scored by two independent raters, and correlated with pertinent clinical and pathological parameters and cancer-specific mortality (CSM; median follow-up: 34 months, interquartile range: 6-60 months). Correlation statistics proved good interobserver agreement in staining evaluation (K-values between 0.62 and 1.00, all p<0.001). Based on consensus decision between both raters, 36 study cases (60%) showed a switch from E-cadherin to N-cadherin (as a hallmark of EMT), which correlated with the presence of lymphovascular invasion (ρ=0.287, p=0.026) while failing to interfere with CSM. Although cadherin switch was correlated with a loss of membranous β-catenin expression (ρ=0.629, p<0.001), none of the study cases showed nuclear β-catenin expression, and only three EMT cases (8.3%) had tumor buds revealing vimentin expression. Our data suggest that roughly half of surgically treated SCCP cases exhibit EMT, a parameter correlating with lymphovascular invasion. However, further studies are clearly needed to validate the so far unresolved possible role of cadherin switch in terms of predicting nodal spread in patients with SCCP. Moreover, the apparently complex mechanisms driving EMT in SCCP should be explored by future studies, as knowledge about these might provide a so far unexploited basis for the development of novel targeted therapies against SCCP with metastatic dissemination.
Research Interests: Immunohistochemistry, Treatment Outcome, Epithelial-Mesenchymal Transition, Germany, Humans, and 14 moreMale, Aged, Middle Aged, Oral Squamous Cell Carcinoma (OSCC), Neoplasm Invasiveness, Observer Variation, Time Factors, Retrospective Studies, Reproducibility of Results, Blood Vessels, Epithelial to Mesenchymal Transition, Vimentin, Proportional Hazards Models, and Predictive value of tests
ABSTRACT This article provides an empirical examination of the Turkish software industry to understand how its current profile, managerial practices and perceptions are shaped by the context of an emerging economy and its cultural... more
ABSTRACT This article provides an empirical examination of the Turkish software industry to understand how its current profile, managerial practices and perceptions are shaped by the context of an emerging economy and its cultural background. In comparison to a developed economy with a very different culture, Austria, employees, know-how, and access to new technologies are perceived as less important, while productivity and sales are considered more important. Marketing to foreign countries as well as policy related factors are perceived as more important barriers, while domestic rivalry, software piracy, and e-business readiness are perceived as smaller growth barriers. The domestic market is relatively developed, but rivalry is low and dominated by large companies, many of which have a close relationship with their few clients. Generally, the companies seem to exhibit a short-sighted perspective, with a limited focus on process maturity, improvement and investments in continuous training of employees, in line with the prevailing culture.
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Abstract Many corporate code developers are the beta testers of open source software. They continue testing until they are sure that they have a stable version to build their code on. In this respect defect predictors play a critical role... more
Abstract Many corporate code developers are the beta testers of open source software. They continue testing until they are sure that they have a stable version to build their code on. In this respect defect predictors play a critical role to identify defective parts of the software. Performance of a defect predictor is determined by correctly finding defective parts of the software without giving any false alarms. Having high false alarms means testers/developers would inspect bug free code unnecessarily. Therefore in this research we focused on ...
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Psychosomatic rehabilitation research increasingly agrees that symptom-related therapies need to be supplemented by work-related therapeutic interventions. However, there is a lack of evaluated diagnostic instruments for determination of... more
Psychosomatic rehabilitation research increasingly agrees that symptom-related therapies need to be supplemented by work-related therapeutic interventions. However, there is a lack of evaluated diagnostic instruments for determination of an indication for and evaluation of specific work-related interventions. This article presents an analysis of the diagnostic quality of work-related self-rating instruments as well as their evaluation from a practical perspective. 281 psychosomatic inpatients showing high levels of occupational stress were studied using a set of work-related questionnaires on admission: individual coping skills (AVEM), work-related therapy motivation (FBTM), work satisfaction (ABB), leisure activities, experienced control at work, as well as occupational concerns and social stressors at work. Furthermore a sub-group of 78 patients who had completed a specific work-related group programme during their inpatient treatment were interviewed three months post-treatment. ...
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Clinical management of incidental prostate cancer (IPC) remains challenging since its clinical course cannot be predicted by conventional histopathology. Aiming to define predictive factors in IPC, we correlated the immunohistochemically... more
Clinical management of incidental prostate cancer (IPC) remains challenging since its clinical course cannot be predicted by conventional histopathology. Aiming to define predictive factors in IPC, we correlated the immunohistochemically detected expression of prostate-specific antigen (PSA), prostatic acid phosphatase (PSAP), alpha-methylacyl-CoA racemase (AMACR, p504s), and androgen receptor in transurethral resection specimens with Gleason scores and histologic staging on the corresponding
Research Interests: Cancer, Immunohistochemistry, Prostate Cancer, Humans, Male, and 14 moreIncidental Findings, Staging, Prostate, Clinical Sciences, Aged, Middle Aged, Prognosis, Androgen Receptor, Protein Tyrosine Phosphatases, Prostate Specific Antigen, Radical Prostatectomy, Predictive value of tests, Adenocarcinoma, and Urogenital System
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The determination of penetration pathways of topically applied substances into the skin is the subject of several investigations. Recently, follicular penetration has become a major focus of interest. To date, a direct, non-invasive... more
The determination of penetration pathways of topically applied substances into the skin is the subject of several investigations. Recently, follicular penetration has become a major focus of interest. To date, a direct, non-invasive quantification of the amount of topically applied substance penetrated into the follicles had not been possible. The development of such a method was the aim of this study. Therefore, the advantages of both stripping techniques, tape stripping and cyanoacrylate skin surface biopsy, were combined and evaluated. Tape stripping was used to remove the part of the stratum corneum that contained the topically applied dye. Subsequently, the follicular contents were ripped off by cyanoacrylate skin surface biopsy. The combined method termed "differential stripping" was evaluated in vitro and in vivo, and the amount of topically applied fluorescent dye penetrated into the hair follicles was quantified after different penetration times. After 30 min, 5% ...
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Transrectal ultrasound guided prostate needle biopsies are routinely performed to diagnose and stage prostate cancer. We prospectively evaluated the safety, morbidity, and complication rate. We studied 336 patients who underwent... more
Transrectal ultrasound guided prostate needle biopsies are routinely performed to diagnose and stage prostate cancer. We prospectively evaluated the safety, morbidity, and complication rate. We studied 336 patients who underwent transrectal ultrasound guided prostate needle biopsy. A post-biopsy questionnaire was sent to the patients 4 weeks after biopsy concerning questions about minor complications. Information on major complications was obtained by telephone interview. There were 2 major and 48 minor complications. The most common complication was hematuria in 6.5% of cases, followed by pain while urinating in 6.0% of cases. There was no statistically significance difference between hematuria and aspirin/thrombolytic drug use (P = 0.170) and between positive microbiology in urine and elevated temperature (P = 0.665). Transrectal ultrasound guided prostate needle biopsy is safe for diagnosing prostate cancer with few major and minor complications. Aspirin/thrombolytic drug use in ...
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Wnt signaling pathways regulate proliferation, motility, and survival in a variety of human cell types. Dickkopf-1 (Dkk-1) is a secreted Wnt antagonist that has been proposed to regulate tissue homeostasis in the intestine. In this... more
Wnt signaling pathways regulate proliferation, motility, and survival in a variety of human cell types. Dickkopf-1 (Dkk-1) is a secreted Wnt antagonist that has been proposed to regulate tissue homeostasis in the intestine. In this report, we show that Dkk-1 is secreted by intestinal epithelial cells after wounding and that it inhibits cell migration by attenuating the directional orientation of migrating epithelial cells. Dkk-1 exposure induced mislocalized activation of Cdc42 in migrating cells, which coincided with a displacement of the polarity protein Par6 from the leading edge. Consequently, the relocation of the microtubule organizing center and the Golgi apparatus in the direction of migration was significantly and persistently inhibited in the presence of Dkk-1. Small interfering RNA-induced down-regulation of Dkk-1 confirmed that extracellular exposure to Dkk-1 was required for this effect. Together, these data demonstrate a novel role of Dkk-1 in the regulation of directi...
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The behavior of Incidental prostate cancer (IPC) cannot be reliably predicted by means of conventional histomorphology. MUC1 (episialin) expression has been linked to poor outcome in peripheral prostate cancer (PC). We aimed to determine... more
The behavior of Incidental prostate cancer (IPC) cannot be reliably predicted by means of conventional histomorphology. MUC1 (episialin) expression has been linked to poor outcome in peripheral prostate cancer (PC). We aimed to determine the so far neglected prognostic role of MUC1 expression in IPC which most commonly represents transition zone cancer. Using Tissue microarray (TMA), we assessed the association between MUC1 expression recorded in transurethral resection specimens of the prostate (TURP chips) and histopathologic outcome parameters (Gleason scores and histologic staging) performed on the subsequent radical prostatectomies (RPs) in a study cohort of 54 patients. Due to tissue loss during arraying and sectioning, a total of 44 (81.5%) tumor samples remained available for immunostaining which was dichotomized by two independent clinical pathologists as being absent or present. MUC1 expression was present in 7 (15.9%) of the 44 IPC immunohistochemically investigated with ...
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Transrectal ultrasound-guided prostate needle biopsies are performed to diagnose prostate cancer. This study prospectively evaluated the safety, morbidity and complication rates with two different ultrasound probes. Three huntred and... more
Transrectal ultrasound-guided prostate needle biopsies are performed to diagnose prostate cancer. This study prospectively evaluated the safety, morbidity and complication rates with two different ultrasound probes. Three huntred and thirty-two patients were biopsied using a biplane 7.5 MHz probe (GE Medical Systems Kretz Ultrasound, Zipf, Austria) and 101 patients using a biplane 5-10 MHz probe (BK-Medical, Herlev, Denmark). Four weeks after the procedure the patients were asked to fill out a questionnaire. There were 3 major and 75 minor complications. The most common complication was haematuria in 8.1% of cases, followed by pain with urination in 5.3% of cases. After changing the ultrasound probe, the complication rates were slightly higher, but no statistical difference in any of the complication rates was found between the two groups. Changing the method within the same team has no influence on complication rates and on prostate cancer detection rates.
Research Interests: Prospective studies, Humans, Ultrasonography, Male, Prostate, and 3 moreAnticancer, Aged, and Middle Aged
Disease-specific survival (DSS) rates were evaluated in 20 patients with primary malignant fibrous histiocytoma (MFH) of the bladder. The most common pathologic finding was the pleomorphic subtype of MFH (55%) with a mean tumor size of... more
Disease-specific survival (DSS) rates were evaluated in 20 patients with primary malignant fibrous histiocytoma (MFH) of the bladder. The most common pathologic finding was the pleomorphic subtype of MFH (55%) with a mean tumor size of 6.8 cm. 10 patients underwent surgery without and 6 patients with adjuvant therapy. Local and systemic rates of progression were 30 and 60% after surgery only compared with 16.7 and 50% after surgery with adjuvant therapy. Although none of the patients showed metastatic dissemination at the time of diagnosis, overall 1- and 2-year DSS rates of only 47.8 and 31.9% were observed. Hence, after the onset of clinical symptoms, the disease runs a very aggressive course regardless of the therapeutic options employed. Although distant dissemination seems to be rare at the time of diagnosis, the prognostic outcome is dismal. The rarity and inconsistency of the currently available case reports on MFH of the bladder hampers the development of therapeutic guideli...
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Epithelial cells form protective barriers that physically separate an organism from the outside world. Rather than being merely static, impregnable shields, epithelia are highly dynamic structures that can adjust their proliferation,... more
Epithelial cells form protective barriers that physically separate an organism from the outside world. Rather than being merely static, impregnable shields, epithelia are highly dynamic structures that can adjust their proliferation, differentiation, and death in response to intrinsic and extrinsic signals. The advantages as well as pitfalls of this flexibility are highlighted in inflammatory disorders such as inflammatory bowel diseases and psoriasis, which are characterized by a chronically dysregulated homeostasis of the epithelium. In recent years, it has become increasingly apparent that epithelial cells communicate with their surroundings through converging, integrated signaling cascades and that even minor alterations in these pathways can have dramatic pathologic consequences. In this review, we discuss how inflammatory cytokines and other signaling molecules, directly or through cross talk, regulate epithelial homeostasis in the intestine, and we highlight parallels and dif...
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To investigate the neural correlates of lucid dreaming. Parallel EEG/fMRI recordings of night sleep. Sleep laboratory and fMRI facilities. Four experienced lucid dreamers. N/A. Out of 4 participants, one subject had 2 episodes of verified... more
To investigate the neural correlates of lucid dreaming. Parallel EEG/fMRI recordings of night sleep. Sleep laboratory and fMRI facilities. Four experienced lucid dreamers. N/A. Out of 4 participants, one subject had 2 episodes of verified lucid REM sleep of sufficient length to be analyzed by fMRI. During lucid dreaming the bilateral precuneus, cuneus, parietal lobules, and prefrontal and occipito-temporal cortices activated strongly as compared with non-lucid REM sleep. In line with recent EEG data, lucid dreaming was associated with a reactivation of areas which are normally deactivated during REM sleep. This pattern of activity can explain the recovery of reflective cognitive capabilities that are the hallmark of lucid dreaming.
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Background. Multivariate models are used to increase prostate cancer (PCa) detection rate and to reduce unnecessary biopsies. An external validation of the artificial neural network (ANN) "ProstataClass" (ANN-Charité) was... more
Background. Multivariate models are used to increase prostate cancer (PCa) detection rate and to reduce unnecessary biopsies. An external validation of the artificial neural network (ANN) "ProstataClass" (ANN-Charité) was performed with daily routine data. Materials and Methods. The individual ANN predictions were generated with the use of the ANN application for PSA and free PSA assays, which rely on age, tPSA, %fPSA, prostate volume, and DRE (ANN-Charité). Diagnostic validity of tPSA, %fPSA, and the ANN was evaluated by ROC curve analysis and comparisons of observed versus predicted probabilities. Results. Overall, 101 (35.8%) PCa were detected. The areas under the ROC curve (AUCs) were 0.501 for tPSA, 0.669 for %fPSA, 0.694 for ANN-Charité, 0.713 for nomogram I, and 0.742 for nomogram II, showing a significant advantage for nomogram II (P = 0.009) compared with %fPSA while the other model did not differ from %fPSA (P = 0.15 and P = 0.41). All models overestimated the pr...
The classification of poorly differentiated carcinomas involving the renal medullary/sinus region might be challenging on conventional histomorphologic grounds alone. However, delineation of high-grade renal cell carcinomas such as... more
The classification of poorly differentiated carcinomas involving the renal medullary/sinus region might be challenging on conventional histomorphologic grounds alone. However, delineation of high-grade renal cell carcinomas such as collecting duct (Bellini) carcinoma from urothelial cell carcinoma of the renal pelvis is critical, as it conveys important therapeutic implications. We assessed the so far neglected differential diagnostic role of protein gene product 9.5, a neuropeptide involved in intracellular proteolysis, in terms of differentiating invasive urothelial cell carcinomas of the renal pelvis from high-grade renal cell carcinomas infiltrating the renal medullary/sinus region. To this aim, 21 invasive urothelial cell carcinomas of the renal pelvis and 27 high-grade renal cell carcinomas (8 renal cell carcinomas with sarcomatoid dedifferentiation and 5 type 1 and 7 type 2 papillary renal cell carcinomas as well as 7 collecting duct carcinomas) were stained with antibodies d...
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Die Erfassung der Gebäudegrundrisse und der Ausstattungsdaten stellt den größten Kostenblock bei der Einführung von CAFM dar. Bis zu 75 % der Kosten können hierauf entfallen. Aus diesem Grund lohnt es sich, die Methoden der Datenerfassung... more
Die Erfassung der Gebäudegrundrisse und der Ausstattungsdaten stellt den größten Kostenblock bei der Einführung von CAFM dar. Bis zu 75 % der Kosten können hierauf entfallen. Aus diesem Grund lohnt es sich, die Methoden der Datenerfassung genau zu kennen und zu optimieren und insbesondere durch eine intelligente Nutzung der vorhandenen Informationsressourcen die Kosten zu senken. In den Planarchiven der Unternehmen
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The proinflammatory cytokine interferon γ (IFNγ ) influences intestinal epithelial cell (IEC) homeostasis in a biphasic manner by acutely stimulating proliferation that is followed by sustained inhibition of proliferation despite... more
The proinflammatory cytokine interferon γ (IFNγ ) influences intestinal epithelial cell (IEC) homeostasis in a biphasic manner by acutely stimulating proliferation that is followed by sustained inhibition of proliferation despite continued mucosal injury. β-Catenin activation has been classically associated with increased IEC proliferation. However, we observed that IFNγ inhibits IEC proliferation despite sustained activation of Akt/β-catenin signaling. Here we show that inhibition of Akt/β-catenin-mediated cell proliferation by IFNγ is associated with the formation of a protein complex containing phosphorylated β-catenin 552 (pβ-cat552) and 14.3.3ζ. Akt1 served as a bimodal switch that promotes or inhibits β-catenin transactivation in response to IFNγ stimulation. IFNγ initially promotes β-catenin transactivation through Akt-dependent C-terminal phosphorylation of β-catenin to promote its association with 14.3.3ζ. Augmented β-catenin transactivation leads to increased Akt1 protein ...
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We assessed the reproducibility and prognostic impact of the... more
We assessed the reproducibility and prognostic impact of the Broders' grading system (BGS) in a cohort of 147 patients with surgically treated penile squamous cell carcinomas. Conventionally stained histology slides were graded according to the BGS in two rounds by two study pathologists. Reproducibility was assessed using ĸ statistics. Multivariable analyses were calculated to predict cancer-specific survival (CSS). The 'mean grade' per pathologist per round was calculated by allocating grade points to each study case (G1-G4: 1-4 points) and dividing the sum of all grade points by the number of cases examined. The BGS showed substantial interobserver variation (59-87% with ĸ = 0.38-0.69) but almost perfect intraobserver reproducibility (91% with ĸ = 0.86 and 96% with ĸ = 0.94, respectively). The 'mean grade' per pathologist remained nearly constant in both rounds of examination (differences ≤0.05 grade points) but differed between the two pathologists (up to 0.4 grade points). In multivariable analyses, the prognostic impact of the BGS in terms of CSS was strongly pathologist-dependent. Clinically and prognostically relevant interobserver discordance concerning the BGS seems, at least in part, to be attributable to inherent 'aggressive' versus 'reserved' grading characteristics of individual pathologists.
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This study aims to clarify whether neuroendocrine differentiation (NED) and/or proliferation activity assessed by means of Ki67 staining index (Ki67SI) might aggravate other established adverse prognostic parameters commonly used for... more
This study aims to clarify whether neuroendocrine differentiation (NED) and/or proliferation activity assessed by means of Ki67 staining index (Ki67SI) might aggravate other established adverse prognostic parameters commonly used for predicting outcome in surgically treated prostate cancer, and to assess inter-observer variability in assigning NED and Ki67 SI. A total of 528 patients surgically treated due to prostate cancer were evaluated in this study. Relevant data were retrospectively obtained by chart review. Immunostaining with antibodies directed against Chromogranin A and Ki67 was performed on archived surgical material, and was evaluated by two independent histopathologists blinded to the specimens. Surveying a median postsurgical follow-up of 46.4 months, postsurgical serum PSA-levels were regularly documented for identifying biochemical progress. Multivariate analysis was performed by means of the Cox regression hazards regression method to evaluate possible aggravations of established adverse prognostic parameters (nodal status, tumour stage, pretherapeutic PSA-level, and Gleason score) by NED and/or Ki67SI. Ki67 SI and NED were shown to significantly aggravate these established adverse prognostic parameters, and were found to be characterized by negligible inter-observer variability. Ki67 SI and NED should be advocated to be rendered by the histopathologist because both parameters can be immunohistochemically determined without much additional expense in time and cost involved. This concept is rewarded by an additional gain of prognostic accuracy in evaluating individual risk profile after surgery.
Research Interests: Nephrology, Urology, Cancer, Immunohistochemistry, Prostate Cancer, and 26 moreMultivariate Analysis, Cell Differentiation, Humans, World, Cox Regression, Variability, Male, Follow-up studies, Index, Differentiation, Clinical Sciences, Aged, Middle Aged, Observer Variation, Adult, Time Factors, Retrospective Studies, Prognosis, Disease Progression, Indexation, Cell Proliferation, Staining, Prostate Specific Antigen, Proportional Hazards Models, Parameter, and Chromogranin A
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Clinical management of incidental prostate cancer (IPC) remains challenging since its clinical course cannot be predicted by conventional histopathology. Aiming to define predictive factors in IPC, we correlated the immunohistochemically... more
Clinical management of incidental prostate cancer (IPC) remains challenging since its clinical course cannot be predicted by conventional histopathology. Aiming to define predictive factors in IPC, we correlated the immunohistochemically detected expression of prostate-specific antigen (PSA), prostatic acid phosphatase (PSAP), alpha-methylacyl-CoA racemase (AMACR, p504s), and androgen receptor in transurethral resection specimens with Gleason scores and histologic staging on the corresponding radicals in a cohort of 54 patients (mean age, 65.9 years; range, 49-80 years). PSAP expression showed a significant correlation with tumor staging (rho = -0.37; p = 0.02) but not with Gleason scores (rho = -0.06; p = 0.69). K-statistics revealed a highly significant moderate interobserver agreement concerning the evaluation of PSAP staining (K = 0.47; p < 0.001). In contrast, the other markers assessed failed to correlate with conventional histopathology. Therefore, PSAP might be predictive of tumor stage in IPC and represent a valuable adjunct for clinical decisions in terms of individual therapeutic management.
Research Interests: Cancer, Immunohistochemistry, Prostate Cancer, Humans, Male, and 14 moreIncidental Findings, Staging, Prostate, Clinical Sciences, Aged, Middle Aged, Prognosis, Androgen Receptor, Protein Tyrosine Phosphatases, Prostate Specific Antigen, Radical Prostatectomy, Predictive value of tests, Adenocarcinoma, and Urogenital System
Alpha-methylacyl-CoA racemase (AMACR, p504S), an enzyme involved in cellular energy metabolism by the oxidation of branched-chain fatty acids, is a biomarker that is known to be overexpressed in prostatic and colorectal carcinoma as well... more
Alpha-methylacyl-CoA racemase (AMACR, p504S), an enzyme involved in cellular energy metabolism by the oxidation of branched-chain fatty acids, is a biomarker that is known to be overexpressed in prostatic and colorectal carcinoma as well as in papillary renal cell carcinoma. We aimed to correlate its immunohistochemically detected expression with histopathological grading in noninvasive bladder cancer in order to hint at a so far unknown role of AMACR in the pathobiology of this tumor entity. Therefore, a cohort of 163 patients (mean age 65.3 years) diagnosed with noninvasive bladder cancer was immunohistochemically investigated in terms of AMACR expression. There was variable positive AMACR staining in 52 (31.9%) of the cases investigated. All tumors were graded by three independent clinical histopathologists according to the 1973 World Health Organization (WHO) and the 1998 WHO/International Society of Urological Pathology (ISUP) system. We found a significant positive correlation between AMACR expression and higher tumor grades using both histopathologic grading schemes. These novel findings clearly allow including high-grade noninvasive bladder carcinomas in the group of AMACR-positive neoplasms and might reflect a so far unknown role of AMACR racemase in the pathobiology and tumor cell energy metabolism of the latter tumor entity.
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In the present study, the transmission of sunlight trough the human skin barrier into the living tissue was investigated in the spectral region between 280 and 700 nm. The experiments were performed with a fiber-based spectrometer on... more
In the present study, the transmission of sunlight trough the human skin barrier into the living tissue was investigated in the spectral region between 280 and 700 nm. The experiments were performed with a fiber-based spectrometer on sliced skin obtained from volunteers with different skin types. One fiber was positioned directly on the skin surface and the second one underneath the skin samples. The distribution of the sunlight under the epidermis was determined. Significant differences were found in the absorption properties of the different skin types, which were mainly determined by the variations in melanin concentration and distribution. It was found that sunscreens for specific ethnic groups need different combinations of UV filters, if a balanced relation between ultraviolet B (UVB) and ultraviolet A (UVA) protection is to be obtained. On the other hand, it could be demonstrated that the human skin is also well protected against visible and near-infrared light by melanin. The higher the skin type category, the better the protection in the visible part of the spectrum of the sun. This stimulates the hot discussion at the present time, as to whether sunscreens should also contain protection compounds in the visible and near-infrared parts of the spectrum.
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The exact qualitative and quantitative analysis of wound healing processes is a decisive prerequisite for optimizing wound care and for therapy control. Transepidermal water loss (TEWL) measurements are considered to be the standard... more
The exact qualitative and quantitative analysis of wound healing processes is a decisive prerequisite for optimizing wound care and for therapy control. Transepidermal water loss (TEWL) measurements are considered to be the standard procedure for assessing the progress of epidermal wound healing. The damage to the stratum corneum correlates with an increased loss of water through the skin barrier. This method is highly susceptible to failure by environmental factors, in particular by temperature and moisture. This study was aimed at comparing TEWL measurements and in vivo laser scanning microscopy (LSM) for the characterization of the epidermal wound healing process. LSM is a high-resolution in vivo method permitting to analyze the kinetics and dynamics of wound healing at a cellular level. While the TEWL values for the individual volunteers showed a wide scattering, LSM permitted the wound healing process to be clearly characterized at the cellular level. However, a comparison between the two methods was very difficult, because the results provided by LSM were images and not numerical. Therefore, a scoring system was set up which evaluates the stages of wound healing. Thus, the healing process could be numerically described. This method is independent of any environmental factors. Providing morphologically qualitative and numerically quantitative analyses of the wound healing process and being far less vulnerable to failure, LSM is advantageous over TEWL.
Research Interests: Water, Kinetics, Wound Healing, Fluorescent Dyes and Reagents, Confocal Microscopy, and 15 moreAdolescent, Humans, Permeability, Female, Male, Young Adult, Epidermis, Water Loss, High Resolution, Adult, Genetic analysis for qualitative and quantitative traits of crop plants, Blister, Laser Scanning Microscopy, Stratum Corneum, and Fluorescein
ABSTRACT Hintergrund und Fragestellung Misserfolge im Sinne von Non-Response psychotherapeutischer Behandlungen wurden bisher kaum systematisch erforscht. Es wird vermutet, dass es bei 25–30% der Patienten zu Misserfolgen und bei 5–10%... more
ABSTRACT Hintergrund und Fragestellung Misserfolge im Sinne von Non-Response psychotherapeutischer Behandlungen wurden bisher kaum systematisch erforscht. Es wird vermutet, dass es bei 25–30% der Patienten zu Misserfolgen und bei 5–10% sogar zu Verschlechterungen kommt. Studiendesign und Untersuchungsmethoden Anhand von Selbsteinschätzungsverfahren und Routinedaten bei Aufnahme und Entlassung [Beck-Depressions-Inventar-II (BDI-II), Brief Symptom Inventory (BSI)] wurde der Therapieerfolg von insgesamt 2323 konsekutiv in stationäre Behandlung aufgenommene Patienten mit depressiven Störungen (F32.0-2, F33.0-2) untersucht. In „Intention-to-treat“(ITT)- und „Completer“-Analysen wurden verschiedene Operationalisierungen von Therapieerfolg (statistische Signifikanz, Effektstärken, klinische Signifikanz) verglichen. Ergebnisse Effektstärken der ITT-Analyse lagen bei 1,59 (BDI-II) bzw. bei 0,86 (BSI) sowie bei 1,64 und 0,89 (Completer-Analyse). Nach den Kriterien der klinischen Signifikanz wurden Response-Raten von 75,5% (BDI-II) bzw. 68,7% (BSI) und Remissionsraten von 62,2% (BDI-II) bzw. 40,8% (BSI) erreicht. Non-Response-Raten, die auch geringe Verbesserungen einschließen, lagen zwischen 23,4% (BDI-II) und 27,4% (BSI); Verschlechterungen traten lediglich bei 1% (BDI-II) bis 3,9% (BSI) der Patienten auf. Die genannten Ergebnisse von Completer-Analysen weisen nur marginale Unterschiede zu Ergebnissen der ITT-Analysen auf. Diskussion Etwa zwei Drittel der depressiven Patienten berichten im Verlauf einer multimodalen stationären, vorrangig psychotherapeutischen Behandlung klinisch signifikante Verbesserungen bezüglich ihrer Primärsymptomatik. Verschlechterungsraten hingegen fielen geringer aus als erwartet. Zur Optimierung der Behandlung erscheint erforderlich, insbesondere Misserfolge bzw. „minor responder“ möglichst frühzeitig im Behandlungsverlauf zu identifizieren.
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Inhibitor of apoptosis-stimulating protein of p53 (iASPP) is the most ancient member of the ASPP family of proteins and an evolutionarily conserved inhibitor of p53. iASPP is also a binding partner and negative regulator of p65RelA.... more
Inhibitor of apoptosis-stimulating protein of p53 (iASPP) is the most ancient member of the ASPP family of proteins and an evolutionarily conserved inhibitor of p53. iASPP is also a binding partner and negative regulator of p65RelA. Because p65RelA and the p53 family members often have opposite effects in controlling cell fate, it is important to understand the cellular context in which iASPP can regulate their activities. To address this question and to study the biological importance of iASPP in vivo, we generated a transgenic mouse in which iASPP expression is controlled by the Cre/loxP recombination system. We observed that iASPP is able to prevent premature cellular senescence in mouse embryonic fibroblasts. iASPP loss resulted in increased differentiation of primary keratinocytes both in vitro and in vivo. In stratified epithelia, nuclear iASPP often colocalized with p63 in the nuclei of basal keratinocytes. Consistent with this, iASPP bound p63 and inhibited the transcriptional activity of both TAp63α and ΔNp63α in vitro and influenced the expression level of p63-regulated genes such as loricrin and involucrin in vivo. In contrast, under the same conditions, p65RelA was frequently expressed as a cytoplasmic protein in the suprabasal layers of stratified epithelia and rarely colocalized with nuclear iASPP. Thus, iASPP is likely to control epithelial stratification by regulating p63's transcriptional activity, rather than p65RelA's. This study identifies iASPP as an inhibitor of senescence and a key player in controlling epithelial stratification.
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We assessed c-MET expression and oncogene amplification in a cohort enrolling 92 surgically treated penile squamous cell carcinomas (PSCCs). A tissue microarray was constructed for c-MET immunohistochemistry (IHC) and chromogenic silver... more
We assessed c-MET expression and oncogene amplification in a cohort enrolling 92 surgically treated penile squamous cell carcinomas (PSCCs). A tissue microarray was constructed for c-MET immunohistochemistry (IHC) and chromogenic silver in situ hybridization (SISH). Two independent pathologists evaluated IHC by employing the breast cancer scoring rules, and scored the presence of MET oncogene amplification and/or polysomy-7. Eighty study cases (87%) showed c-MET expression. No study case had MET oncogene amplification, but 42 patients (45.7%) had polysomy-7. Polysomy-7 showed a significant positive correlation with c-MET expression (ρ=0.323, p=0.002). Neither c-MET expression nor polysomy-7 was associated with histopathologic parameters or with cancer-specific survival (median post-surgical follow-up 32 months). Our data suggest that the majority of PSCCs exhibit c-MET expression which is not associated with oncogene amplification, but might be attributable to polysomy-7. Further studies should investigate the expression and activation of downstream molecules functionally involved in c-MET pathway signaling, and clarify the so far unresolved role of c-MET inhibitors as potential targeted therapies in PSCCs with metastatic dissemination.
Research Interests: Immunohistochemistry, Biopsy, In Situ Hybridization, Multivariate Analysis, Humans, and 15 moreMale, Aneuploidy, Risk factors, Phenotype, Clinical Sciences, Aged, Middle Aged, Oral Squamous Cell Carcinoma (OSCC), Time Factors, Retrospective Studies, Prognosis, Chi Square Distribution, Risk Factors, Proportional Hazards Models, and Predictive value of tests
Incidental prostate cancer (IPC) has a substantially variable clinical course which cannot be predicted by conventional histopathologic examination of transurethral resection specimens of the prostate (TURP chips). Therefore, efforts... more
Incidental prostate cancer (IPC) has a substantially variable clinical course which cannot be predicted by conventional histopathologic examination of transurethral resection specimens of the prostate (TURP chips). Therefore, efforts should be directed towards defining the natural history of individual IPC. Recently, expression of CD44s (standard isoform), a transmembranous glycoprotein, has been linked to prognostic outcome in prostate cancer, but its prognostic role in IPC has been neglected so far. We present a multicentre study which evaluates immunohistochemically the largest cohort of IPC patients to date, aiming to correlate CD44s expression in the TURP chips with histopathologic outcome parameters (Gleason scores and histologic staging) performed on subsequent radical prostatectomies (RPs) in a cohort of 54 patients who underwent prostatectomy due to IPC. CD44s expression recorded in the TURP chips showed a stronger (inverse) association with Gleason scores performed on the corresponding RPs than did other conventional prognostic variables and, therefore, might become a valuable adjunct to better predict outcome in IPC prior to radical prostatectomy. Advanced prospective studies should aim to define cut-point values of CD44s expression for separating aggressive tumours from their indolent counterparts, and should also assess possible associations with clinical follow-up data (e.g. progression-free survival) in IPC.
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Chemotherapeutic agents are active in advanced bladder cancer, and various combinations have shown promising results. The objective of this study was to evaluate the efficacy of combination chemotherapy with gemcitabine, paclitaxel, and... more
Chemotherapeutic agents are active in advanced bladder cancer, and various combinations have shown promising results. The objective of this study was to evaluate the efficacy of combination chemotherapy with gemcitabine, paclitaxel, and cisplatin in patients with advanced urothelial carcinoma. Fifty-nine patients with metastatic or locally advanced transitional cell carcinoma of the urothelium were treated between 2000 and 2005. No patient had received any previous systemic chemotherapy. All patients received chemotherapy intravenously with gemcitabine at a dose of 1000 mg/m(2) on days 1 and 8, paclitaxel at a dose of 80 mg/m(2) on days 1 and 8, and cisplatin at a dose of 50 mg/m(2) on day 2. Treatment courses were repeated every 21 days. After completion of four to six courses in this regimen an intravenous application of gemcitabine was repeated every 28 days at a dose of 1000 mg/m(2). Fifty-nine patients were treated between 2000 and 2005. Nine patients (15%) had >or=1 visceral site of metastases, and no patient had received any previous systemic chemotherapy. Forty-eight patients (81%) achieved objective responses to treatment (56% complete responses). The median actuarial survival was 22 months, and the actuarial 1-year and 2-year survival rates were 68% and 39%, respectively. After a median follow-up of 17.5 months, 29 patients remained alive and 25 were free of disease progression. The median progression-free survival for the entire group was 10 months. The median survival time for patients with an Eastern Cooperative Oncology Group (ECOG) status of 0, 1, and 2 was 37.5, 17, and 12 months, respectively. Grade 3-4 neutropenia occurred in 39% of the patients. The combination of gemcitabine, paclitaxel, and cisplatin is a highly effective and tolerable regimen for patients with advanced urothelial carcinoma. This treatment should be considered as a suitable option that deserves further prospective evaluation. The ECOG performance status is an important predictive factor for survival.
Research Interests: Survival Analysis, Treatment Outcome, Humans, Female, Male, and 4 morePaclitaxel, Cisplatin, Aged, and Middle Aged
Research Interests: Immunology, Wound Healing, Apoptosis, Genitourinary Pathology, Biological Sciences, and 16 moreCaspases, Cell line, Humans, Intestinal Mucosa, Mice, Animals, Beta-Catenin, Mucosal Immunology, Colitis, Cell nucleus, Rats, Epithelial cells, Homeostasis, Cell Proliferation, Protein Transport, and Gene Expression Regulation
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Abstract: The economic justification of investments in information technology (IT) is a basic issue for IT management in private and in public-sector organisations. Usually, the expenses made for any investment are compared to the cost... more
Abstract: The economic justification of investments in information technology (IT) is a basic issue for IT management in private and in public-sector organisations. Usually, the expenses made for any investment are compared to the cost saved. While the costs for implementing a new system are uncertain, only a small percentage of the benefits accrues as cost savings given the type of IT systems used today and the particularities of the public-sector. In this paper, we present a methodology for the monetary quantification of the benefits resulting ...
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Abstract There has been considerable discussion on the possible impacts of open source software development practices, especially in regard to the quality of the resulting software product. Recent studies have shown that analyzing data... more
Abstract There has been considerable discussion on the possible impacts of open source software development practices, especially in regard to the quality of the resulting software product. Recent studies have shown that analyzing data from source code repositories is an efficient way to gather information about project characteristics and programmers, showing that OSS projects are very heterogeneous in their team structures and software processes. However, one problem is that the resulting process metrics measuring attributes of the ...
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To evaluate the prognostic impact of the width of negative surgical margins (NSM) and associated and preinvasive lesions at the NSM in patients with penile squamous cell cancer (PSC). Enrolling 87 patients with NSM who underwent surgery... more
To evaluate the prognostic impact of the width of negative surgical margins (NSM) and associated and preinvasive lesions at the NSM in patients with penile squamous cell cancer (PSC). Enrolling 87 patients with NSM who underwent surgery for PSC, the archived margin slides and entirely wax-embedded surgical margins were retrieved from the pathology files. After step sections were cut, margins were stained with antibodies against CK5/6, p16, p53 and Ki-67 and subjected to in situ hybridisation for high-risk human papillomavirus (HPV). All NSM were histologically examined for squamous hyperplasia (SH), lichen sclerosus (LS) and subtypes of penile intraepithelial neoplasia (PeIN). Then, histological findings were correlated with cancer-specific mortality (CSM, median follow-up 34 months; IQR 6-70). All NSM were negative for high-risk HPV and exhibited SH (p16 and p53 negative, Ki-67 variably positive), LS (p16 negative, variable p53 and Ki-67 positivity) and differentiated PeIN (dPeIN; p16 negative, Ki-67 positive, variable p53 positivity) in 28 (32%), 30 (34%) and 22 (25%) cases, respectively, whereas PeIN subtypes other then dPeIN did not occur. Pathological tumour stage was the only independent predictive parameter with respect to CSM in the multivariable analysis (p=0.001). SH, LS and dPeIN are frequent histological findings at the NSM of surgically treated PSC. However, neither the width of the NSM nor dPeIN, LS or SH at the NSM influences prognostic outcome.
Research Interests: Immunohistochemistry, Treatment Outcome, Dermatology, Clinical Pathology, In Situ Hybridization, and 17 moreMultivariate Analysis, Germany, Humans, Male, Hyperplasia, Risk factors, Skin Diseases, Clinical Sciences, Aged, Middle Aged, Oral Squamous Cell Carcinoma (OSCC), Precancerous Conditions, Time Factors, Retrospective Studies, Risk Factors, Proportional Hazards Models, and Predictive value of tests
Penile, vulvar and anal squamous cell carcinomas (SCCs) share histomorphological overlap and are prone to lymphatic dissemination into inguinal nodes. Anal SCCs might derive from the anorectal zone (ARZ), anal transitional zone, squamous... more
Penile, vulvar and anal squamous cell carcinomas (SCCs) share histomorphological overlap and are prone to lymphatic dissemination into inguinal nodes. Anal SCCs might derive from the anorectal zone (ARZ), anal transitional zone, squamous zone or from perianal skin. These anatomically distinct zones differ in terms of their embryological development. We sought to investigate the role of caudal-related homeobox 2 (CDX2), a homeobox gene implicated in the development and anterior/posterior pattern specification from duodenum to rectum including the ARZ, in terms of narrowing the possible sites of origin to be considered in the setting of SCC with unknown primary presenting with histologically confirmed inguinal lymph node metastasis. By immunohistochemistry (IHC) employing a panel of antibodies directed against CK5/6, CK7, CK20, p63, p16, CEA and CDX2, we compared 89 penile, 11 vulvar and eight anal SCCs with respect to their staining profiles. Moreover, anal SCCs were subjected to in situ hybridisation (ISH) for high-risk human papillomavirus (HPV) subtypes. By IHC, CDX2 expression was observed in 2/8 anal SCCs (25%) while being absent from all penile and vulvar SCCs examined. High-risk HPV subtypes were detected by ISH in all anal SCCs examined, which were uniformly p16-positive by IHC. CDX2 might be valuable in terms of narrowing the possible sites of origin to be considered in the setting of SCC with unknown primary presenting with inguinal lymph node metastasis. However, despite its favourable specificity, the diagnostic benefit achieved by this observation is limited by the low sensitivity.
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The cell-surface carbohydrate Lewis(y) antigen (blood group 8, BG8) has recently been investigated in bladder cancer, but its role in the differential diagnosis of flat urothelial lesions of the bladder has not yet been systematically... more
The cell-surface carbohydrate Lewis(y) antigen (blood group 8, BG8) has recently been investigated in bladder cancer, but its role in the differential diagnosis of flat urothelial lesions of the bladder has not yet been systematically evaluated. 30 carcinoma in situ (CIS) and 30 non-CIS conditions of the bladder mucosa (four dysplasia and 26 reactive atypia according to consensus diagnoses) were comparatively assessed in terms of their Lewis(y) antigen staining profiles by two independent clinical pathologists. Lewis(y) antigen expression differed significantly (p<0.001) between CIS (full thickness expression throughout the entire urothelium including the basal cell layer) and non-CIS conditions (patchy discontinuous expression restricted to individual cells scattered singly throughout the urothelial mucosa). The four dysplastic study cases showed Lewis(y) antigen expression more closely related to the staining profiles observed in most of the reactive urothelial atypia. κ statistics showed excellent inter-observer agreement between both raters in terms of Lewis(y) antigen staining evaluation (κ=0.9, p<0.001). The data hint at the cell-surface carbohydrate Lewis(y) antigen as a so far neglected diagnostically useful marker to aid in the histological classification of conventionally equivocal flat urothelial lesions of the bladder in contemporary surgical pathology practice.
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To evaluate the role of p53, p21 and cyclin D1 expression in patients with penile cancer (PC). Paraffin-embedded tissues from PC specimens from six pathology departments were subjected to a central histopathological review performed by... more
To evaluate the role of p53, p21 and cyclin D1 expression in patients with penile cancer (PC). Paraffin-embedded tissues from PC specimens from six pathology departments were subjected to a central histopathological review performed by one pathologist. The tissue microarray technique was used for immunostaining which was evaluated by two independent pathologists and correlated with cancer-specific survival (CSS). κ-statistics were used to assess interobserver variability. Uni- and multivariable Cox proportional hazards analysis was applied to assess the independent effects of several prognostic factors on CSS over a median of 32 months (IQR 6-66 months). Specimens and clinical data from 110 men treated surgically for primary PC were collected. p53 staining was positive in 30 and negative in 62 specimens. κ-statistics showed substantial interobserver reproducibility of p53 staining evaluation (κ=0.73; p<0.001). The 5-year CSS rate for the entire study cohort was 74%. Five-year CSS was 84% in p53-negative and 51% in p53-positive PC patients (p=0.003). Multivariable analysis showed p53 (HR=3.20; p=0.041) and pT-stage (HR=4.29; p<0.001) as independent significant prognostic factors for CSS. Cyclin D1 and p21 expression were not correlated with survival. However, incorporating p21 into a multivariable Cox model did contribute to improved model quality for predicting CSS. In patients with PC, the expression of p53 in the primary tumour specimen can be reproducibly assessed and is negatively associated with cancer specific survival.
Research Interests: Immunohistochemistry, Treatment Outcome, Risk assessment, Clinical Pathology, Multivariate Analysis, and 15 moreGermany, Humans, Male, Risk factors, Clinical Sciences, Time Factors, Survival Rate, Retrospective Studies, Prognosis, Reproducibility of Results, Chi Square Distribution, Risk Factors, Risk Assessment, Proportional Hazards Models, and Predictive value of tests
Overexpression of periostin, a secreted cell adhesion molecule, has been reported to enhance invasion and angiogenesis in squamous cell carcinomas (SCCs) derived from different anatomic sites. We studied the so far neglected periostin... more
Overexpression of periostin, a secreted cell adhesion molecule, has been reported to enhance invasion and angiogenesis in squamous cell carcinomas (SCCs) derived from different anatomic sites. We studied the so far neglected periostin expression profiles in penile SCCs and evaluated its association with pertinent clinicopathologic variables. Paraffin-embedded tissues from 89 patients with surgically treated penile SCCs were subjected to a central histopathologic review performed by one pathologist. Then, tissue microarray technique was employed for periostin immunostaining which was evaluated by two independent raters. Kappa (κ)-statistics were used to assess interobserver variability. Spearman correlations as well as uni- and multivariable Cox proportional hazards analysis were applied to assess the association between periostin expression and clinicopathologic parameters. Mean postsurgical follow-up was 31.5 months (IQR 6-66). Periostin expression was recorded in 39/89 penile SCCs (44%). K-statistics disclosed substantial interobserver agreement for epithelial and stromal staining evaluation (K-values 0.76 vs 0.83, p values <0.001). High periostin expression in either stroma or tumour epithelia showed a significant positive correlation with tumour size, histologic grade and pT-stage. In the multivariable Cox models including pT-stage, pN status, grading and the patients' age at the time of surgery, periostin expression independently predicted cancer-specific survival (CSS). Immunohistochemically, periostin is not infrequently expressed in penile cancer, and might become a valuable tool to independently predict CSS after surgical treatment. Further studies should clarify the so far unresolved usefulness of periostin to be employed as a possible molecular target in antineoplastic therapy in metastasised penile SCCs.
Research Interests: Immunohistochemistry, Treatment Outcome, Clinical Pathology, Multivariate Analysis, Humans, and 13 moreMale, Risk factors, Clinical Sciences, Oral Squamous Cell Carcinoma (OSCC), Observer Variation, Epithelial cells, Time Factors, Stromal Cells, Reproducibility of Results, Risk Factors, Proportional Hazards Models, Predictive value of tests, and Cell Adhesion Molecules
To systematically compare different approaches for evaluating mucosal proliferative activity regarding their diagnostic role for delineating flat lesions of the bladder mucosa. 32 carcinoma in situ (CIS) and 31 flat non-CIS conditions... more
To systematically compare different approaches for evaluating mucosal proliferative activity regarding their diagnostic role for delineating flat lesions of the bladder mucosa. 32 carcinoma in situ (CIS) and 31 flat non-CIS conditions (low-grade dysplasia and reactive atypia) of the bladder mucosa were assessed by two independent pathologists in two rounds in terms of their proliferative activity assessed by the mitotic counts on H&E-stained sections (mitoses per mm(2)) and immunohistochemically using the MIB-1 antibody and the mitosis marker phosphohistone H3 (PHH3). Two different approaches for immunoscoring (percentage of stained nuclei vs dichotomised height of mucosal staining considering lower half vs full-thickness marker expression) were applied. κ statistics were used to evaluate interobserver and intraobserver reproducibility. Scoring the percentage of Ki67 expressing cell nuclei seems to be superior to dichotomisation of the height of mucosal staining as well as to PHH3 immunostaining and conventional mitotic counts in terms of delineating CIS from flat non-CIS conditions. This approach shows substantial (κ=0.62-0.65; p<0.001) interobserver and substantial to almost perfect (κ=0.67-0.83; p<0.001) intraobserver reproducibility. The MIB-1 antibody is a useful adjunct in the differential diagnosis of conventionally challenging flat lesions of the bladder mucosa. In particular, 16% or more Ki67 positive cell nuclei favours CIS over flat non-CIS conditions, whereas 15% or less Ki67 positive cell nuclei is supportive of non-CIS conditions. However, due to some important limitations of MIB-1 staining, the MIB-1 antibody should be used as a component of a panel.
Research Interests: Immunohistochemistry, Clinical Pathology, Germany, Humans, Female, and 17 moreMale, Monoclonal Antibodies, Differential Diagnosis, Phosphorylation, Clinical Sciences, Aged, Middle Aged, Histones, Observer Variation, Adult, Prognosis, Reproducibility of Results, Chi Square Distribution, Cell Proliferation, Mitotic Index, Predictive value of tests, and Urinary Bladder
In this paper we will analyse sourcing decisions in the finance sector, dealing with a mature area, IT outsourcing and a relatively new field, operations outsourcing. For introducing this topic, we will first detail the current state in... more
In this paper we will analyse sourcing decisions in the finance sector, dealing with a mature area, IT outsourcing and a relatively new field, operations outsourcing. For introducing this topic, we will first detail the current state in outsourcing of IT processes and services, using several studies already published and also a new empirical investigation of Austria's top 100 companies. More importantly, the trend towards operations outsourcing in the finance sector will be discussed. We will analyse the operations sourcing decision in general and give ...
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Abstract This paper explores the impacts associated with different software process models on the staff. The main research question addressed is whether any process model leads to a higher satisfaction of staff, and less human resource... more
Abstract This paper explores the impacts associated with different software process models on the staff. The main research question addressed is whether any process model leads to a higher satisfaction of staff, and less human resource related problems, including staff turnover or increased stress levels. This issue is empirically investigated using a set of projects from 15 different software developing companies. Agile-oriented models are not necessarily limited to small projects, but both groups showed nearly identical distributions ...
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ABSTRACT Motivated by information technology evaluation problems identified in a large public sector organization, we propose how evaluation requirements can be supported by a framework combining different models andmethods from... more
ABSTRACT Motivated by information technology evaluation problems identified in a large public sector organization, we propose how evaluation requirements can be supported by a framework combining different models andmethods from information systems evaluation theory. The article extends the content, context, process perspectives of organizational change with operations research techniques and demonstrates the approach in practice for an Enterprise Resource Planning evaluation.
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Stromal remodeling (SR), characterized by focal loss of CD34(+) fibrocytes paralleled by a gain of α-smooth muscle actin (α-SMA)-positive myofibroblasts, has been reported in several cancer types. However, the role of SR in invasive... more
Stromal remodeling (SR), characterized by focal loss of CD34(+) fibrocytes paralleled by a gain of α-smooth muscle actin (α-SMA)-positive myofibroblasts, has been reported in several cancer types. However, the role of SR in invasive penile squamous cell cancer (PSC) has not been investigated so far. We compared 90 surgically treated PSCs (study group) and 55 control specimens (33 foreskins and 22 differentiated penile intraepithelial neoplasias) for the presence of stromal CD34(+) fibrocytes and α-SMA-positive myofibroblasts scored by independent raters. Multivariate proportional hazards regression analysis was used to assess the impact of staining profiles on cancer-specific mortality of the 90 PSCs (median follow-up, 32 months; interquartile range, 6-64). The incidence of SR differed significantly between study and control group specimens (51.1% versus 9.1%; P < .001). Five years postsurgically, 24% and 46% of the study patients without and with SR had succumbed to their PSC (P = .010). After adjusting for the age at the time of surgery, type of surgery, tumor size, Broders' grade, pT stage, and nodal status, study patients with SR showed 3.76-fold increased cancer-specific mortality (95% confidence interval, 1.3-10.5; P = .012). Our findings suggest that SR might have prognostic as well as some limited differential diagnostic value in terms of delineating invasive PSC from preinvasive lesions. However, our preliminary data clearly need to be validated by larger advanced studies in the future.
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Research Interests: Biopsy, Humans, Intestinal Mucosa, Ulcerative colitis, Female, and 19 moreMale, Bacteria, Clinical Sciences, Colitis, Middle Aged, Spectrum, Fluorescent in situ hybridization, Adult, Feces, Gut, Mucus, Abdominal Surgery, Bacterial translocation, Appendix, Acute Appendicitis, Alcian blue, ENEMA, Inflammatory response, and Acute Disease
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ERP implementation projects have received enormous attention in the last years, due to their importance for organisations, as well as the costs and risks involved. The estimation of effort and costs associated with new projects therefore... more
ERP implementation projects have received enormous attention in the last years, due to their importance for organisations, as well as the costs and risks involved. The estimation of effort and costs associated with new projects therefore is an important topic. Unfortunately, there is still a lack of models that can cope with the special characteristics of these projects. As the main focus lies in adapting and customising a complex system, and even changing the organisation, traditional models like COCOMO can not easily be applied. In this article, ...
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Expression of the tight junction protein junctional adhesion molecule-A (JAM-A) has been linked to proliferation and tumour progression. However, a direct role for JAM-A in regulating proliferative processes has not been shown. By using... more
Expression of the tight junction protein junctional adhesion molecule-A (JAM-A) has been linked to proliferation and tumour progression. However, a direct role for JAM-A in regulating proliferative processes has not been shown. By using complementary in vivo and in vitro approaches, we demonstrate that JAM-A restricts intestinal epithelial cell (IEC) proliferation in a dimerization-dependent manner, by inhibiting Akt-dependent β-catenin activation. Furthermore, IECs from transgenic JAM-A(-/-)/β-catenin/T-cell factor reporter mice showed enhanced β-catenin-dependent transcription. Finally, inhibition of Akt reversed colonic crypt hyperproliferation in JAM-A-deficient mice. These data establish a new link between JAM-A and IEC homeostasis.
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Research Interests: Biochemistry, Immunology, Humans, Intestinal Mucosa, Endothelial Cells, and 15 moreUlcerative colitis, Female, Male, Young Adult, Monoclonal Antibodies, Aged, Intestines, Middle Aged, C reactive protein, Adult, Monocytes, Tumor necrosis factor-alpha, Glucocorticoids, Crohn Disease, and Inflammatory Bowel Diseases
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Abstract: In this paper we detail the results from an empirical study concerning differences in characteristics of the enterprise resource planning (ERP) system selection process between small or medium and large sized organizations. In... more
Abstract: In this paper we detail the results from an empirical study concerning differences in characteristics of the enterprise resource planning (ERP) system selection process between small or medium and large sized organizations. In particular we address the fields of software packages considered and chosen, the weights assigned to different selection criteria, the size and structure of the team responsible for the decision, the methods employed and the effort expended.
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Executive Summary: This document explores some of the possibilities of exploitation of the results of the FLOSSmetrics project for industrial use. For this, two specific case studies have identified, along with the related requirements on... more
Executive Summary: This document explores some of the possibilities of exploitation of the results of the FLOSSmetrics project for industrial use. For this, two specific case studies have identified, along with the related requirements on what would be most interesting results. ...
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Defective apoptosis of mucosal cell populations seems to be a relevant pathogenetic mechanism in inflammatory bowel disease (IBD). It has been suggested that the induction of apoptosis in various effector cells may be a relevant... more
Defective apoptosis of mucosal cell populations seems to be a relevant pathogenetic mechanism in inflammatory bowel disease (IBD). It has been suggested that the induction of apoptosis in various effector cells may be a relevant therapeutic mechanism in IBD. Indeed, it was shown that different drugs used for treatment of IBD have the capacity to induce apoptosis in T cells or monocytes in vitro and in vivo. However, it remains unclear whether these observations are related to clinical efficacy of these agents. TNF-alpha is one of the most relevant proinflammatory mediators in IBD and anti-TNF treatment has been shown to be of particular benefit for patients with IBD. It could subsequently be shown that various anti-TNF-alpha agents, such as infliximab and adalimumab, can induce apoptosis in activated monocytes and lymphocytes in vitro and in vivo. This mechanism requires reverse signaling via transmembranous TNF, thereby eliciting a signal transduction cascade that results in programmed cell death. Although other mechanisms might also contribute to the clinical effect of anti-TNF-alpha, current data suggest that apoptosis is a relevant mechanism that is associated with clinical efficacy of anti-TNF agents. Induction of apoptosis in activated monocytes or T cells may be regarded as therapeutic tool not only for anti-TNF agents, but also for other drugs used in IBD. Future strategies should focus on identification of mechanisms that prevent apoptosis in the mucosa of patients with IBD and in targeting apoptotic pathways as a therapeutic strategy in IBD.
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We present the implementation of Virtual Notes, an annotation service on the World Wide Web using only standard Internet technology. Therefore Virtual Notes are immediately usable by anyone on the WWW without preparation. This makes the... more
We present the implementation of Virtual Notes, an annotation service on the World Wide Web using only standard Internet technology. Therefore Virtual Notes are immediately usable by anyone on the WWW without preparation. This makes the solution especially suited for environments lacking a coherent workgroup, eg teaching or research. Also described are the user interface, several use cases and the administrative side of the annotation service, where the overhead for employing Virtual Notes has been minimized
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In this paper we detail the results from an empiricalstudy concerning differences in characteristics of the ERPsystem selection process between small or medium andlarge sized organizations. In particular we address thefields of software... more
In this paper we detail the results from an empiricalstudy concerning differences in characteristics of the ERPsystem selection process between small or medium andlarge sized organizations. In particular we address thefields of software packages considered and chosen, theweights assigned to different selection criteria, thepersons involved in this process, the methods employedand implementation characteristics such as costs andduration. IntroductionAn Enterprise Resource Planning (ERP) system is ...
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Abstract This paper describes a method to determine the possibility of combining two or more process models using an approach similar to the proof of (partial) correct-ness of algorithms by determining the weakest precon-dition and... more
Abstract This paper describes a method to determine the possibility of combining two or more process models using an approach similar to the proof of (partial) correct-ness of algorithms by determining the weakest precon-dition and postcondition. This method also allows the analysis of process models with regard to their semantic correctness. The approach is described and demonstrated on an example process.
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Abstract Patterns can help us adapt faster to shifting environmental conditions, by acknowledging similarities with previously encountered problems, and identifying key characteristics in solutions that succeeded in the past. By a... more
Abstract Patterns can help us adapt faster to shifting environmental conditions, by acknowledging similarities with previously encountered problems, and identifying key characteristics in solutions that succeeded in the past. By a methodical deconstruction of tacit knowledge, patterns can express both internalized information about a past challenge, and intuition about the critical aspects of the proper response in an explicit format that can be studied, perfected, taught and applied to new, unfamiliar situations. Currently in ...
Open source software has opened up a new possibility for corporations that are currently developing software, namely developing with open source software. This can be done either using existing components and projects and build upon their... more
Open source software has opened up a new possibility for corporations that are currently developing software, namely developing with open source software. This can be done either using existing components and projects and build upon their results or release own projects in an early stage with free code and hope for a community to form around this project. These strategies complement the traditional options of developing the solution in-house or buying it from external sources. In this paper we put this decision regarding open source in the ...
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We aim to model and analyze possible cooperative advertising strategies in the context of a gaming platform manufacturer and a game software publisher in the video game industry. The analysis takes on a game theoretic approach in... more
We aim to model and analyze possible cooperative advertising strategies in the context of a gaming platform manufacturer and a game software publisher in the video game industry. The analysis takes on a game theoretic approach in understanding the impact of a video game's total advertising budget and the co-op advertising sharing policy on each player's preferred strategy and corresponding payoffs. Non-cooperative schemes have been demonstrated in which Stackelberg and Nash equilibriums were identified. These were ...
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Marketing a brand and analyzing the effectiveness of promotional campaigns have always been major topics for marketing. In today's world, marketers use many data sources to analyze the behavior and responses of their consumers. This... more
Marketing a brand and analyzing the effectiveness of promotional campaigns have always been major topics for marketing. In today's world, marketers use many data sources to analyze the behavior and responses of their consumers. This mainly involves data from Point of Sales, consumer surveys or home visits. However, with the advancement of web technologies, there is one more place where data is available: User generated content (UGC) from Web 2.0 applications. The purpose of this conceptual paper is to formulate ...
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In the last years, two movements have been widely discussed in the software development community: Agile and open source development. Both have faced some of the same criticism, and both claim some of the same benefits. This paper poses... more
In the last years, two movements have been widely discussed in the software development community: Agile and open source development. Both have faced some of the same criticism, and both claim some of the same benefits. This paper poses the question whether open source software development is in accordance with agile software development principles and therefore well within the planning spectrum. To this end, the general principles of both movements are detailed and compared, and some empirical data from ...
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Abstract This study analyses the types of business models that venture capital firms prefer when investing into open source software projects in particularly for Turkish companies. Interviews have been done with venture capital firms... more
Abstract This study analyses the types of business models that venture capital firms prefer when investing into open source software projects in particularly for Turkish companies. Interviews have been done with venture capital firms operating in Turkey in order to find out their approach to start-ups generating revenue with open source-related business models. The questions that have been asked to venture capital firms aimed to reveal the proportion of open source startup investments to the total investments.
Executive Summary: This report details the focussed studies which were undertaken using the FLOSSMetrics database and data set. They do not intend to conform a comprehensive analysis of FLOSS development, but a set of examples of how the... more
Executive Summary: This report details the focussed studies which were undertaken using the FLOSSMetrics database and data set. They do not intend to conform a comprehensive analysis of FLOSS development, but a set of examples of how the data collected by FLOSSMetrics can be used for research studies. All the studies performed have in common some context related to software development.
1. Software-M etri k en (a) G rundlagen (b) Lines-of-C ode (c) Cy clomatic C omple x it y (d) H alstead-M a'(e) M etri k en der ob jek t-orientierten P rogrammierung 2. Aufwandsschxat z ung (a) G rundlagen (b) C Oc Om O (c) M odell von P... more
1. Software-M etri k en (a) G rundlagen (b) Lines-of-C ode (c) Cy clomatic C omple x it y (d) H alstead-M a'(e) M etri k en der ob jek t-orientierten P rogrammierung 2. Aufwandsschxat z ung (a) G rundlagen (b) C Oc Om O (c) M odell von P utnam (d) F unction P oints (e) N icht-algorithmische V erfahren (f) Einsat z in Organisationen, D atengewinnung und V alidierung
During the last years, considerable research effort has been concentrated on free/libre/open source software. Of special interest to scholars worldwide has been whether the development and the resulting systems are significantly different... more
During the last years, considerable research effort has been concentrated on free/libre/open source software. Of special interest to scholars worldwide has been whether the development and the resulting systems are significantly different from the development of software within a commercial and corporate environment, for which methods and tools aimed at improving the speed, quality and overall efficiency have been developed over decades.
In this paper, we propose to arrive at an assessment and evaluation of open source projects based on an analysis of their growth rates in several aspects. These include code base, developer number, bug reports and downloads. Based on this... more
In this paper, we propose to arrive at an assessment and evaluation of open source projects based on an analysis of their growth rates in several aspects. These include code base, developer number, bug reports and downloads. Based on this analysis and assessment, a well-known portfolio planning method, the BCG matrix, is employed for arriving at a very broad classification of open source projects.
• Definition von Open Source:–free redistribution–inclusion of the source code–possibility for modifications and derived works, which must be allowed to be distributed under the same terms as the original software–integrity of author's... more
• Definition von Open Source:–free redistribution–inclusion of the source code–possibility for modifications and derived works, which must be allowed to be distributed under the same terms as the original software–integrity of author's source code–no discrimination against persons, groups or fields of endeavor
Social choice deals with aggregating the preferences of a number of voters into a collective preference. We will use this idea for software project effort estimation, substituting the voters by project attributes. Therefore, instead of... more
Social choice deals with aggregating the preferences of a number of voters into a collective preference. We will use this idea for software project effort estimation, substituting the voters by project attributes. Therefore, instead of supplying numeric values for various project attributes that are then used in regression or similar methods, a new project only needs to be placed into one ranking per attribute, necessitating only ordinal values.
A wealth of successful software applications has been brought forward by Free/Libre Open Source Software (FLOSS); the new software development paradigm based on volunteer participation and open development processes. FLOSS plays an... more
A wealth of successful software applications has been brought forward by Free/Libre Open Source Software (FLOSS); the new software development paradigm based on volunteer participation and open development processes. FLOSS plays an increasingly important role in the ICT sector in particular, and the world economy in general. It is therefore interesting to attempt to estimate the economic impact of FLOSS.
Abstract: Immer mehr Unternehmen setzen betriebswirtschaftliche Standardsoftwarepakete wie beispielsweise SAP R/3 oder BaaN ein. Die Auswahl und die Einführung solcher Systeme stellt für die meisten Unternehmen ein strategisch wichtiges... more
Abstract: Immer mehr Unternehmen setzen betriebswirtschaftliche Standardsoftwarepakete wie beispielsweise SAP R/3 oder BaaN ein. Die Auswahl und die Einführung solcher Systeme stellt für die meisten Unternehmen ein strategisch wichtiges IT-Projekt dar, das mit massive Risiken verbunden ist. Bei der Auswahl des am besten geeigneten Systems gilt es einen Gruppenentscheidungsprozess zu unterstützen.
In this chapter, we argue for adopting mechanisms from the field of social choice for effort estimation. Social choice deals with aggregating the preferences of a number of individuals into a single ranking. We will use this idea,... more
In this chapter, we argue for adopting mechanisms from the field of social choice for effort estimation. Social choice deals with aggregating the preferences of a number of individuals into a single ranking. We will use this idea, substituting these voters by different project attributes. Therefore a new project only needs to be placed into rankings per attribute, necessitating only ordinal values.
Abstract: This paper makes the case for adopting a risk measure from the finance sector for IS/IT project and portfolio evaluation. The proposed value-at-risk approach constitutes a well-tested approach in high-risk environments,... more
Abstract: This paper makes the case for adopting a risk measure from the finance sector for IS/IT project and portfolio evaluation. The proposed value-at-risk approach constitutes a well-tested approach in high-risk environments, especially banking, and reports the expected maximum loss (or worst loss) over a target horizon within a given confidence interval. Value-at-risk is computed using either an analytical, parametric approach, or resorting to simulation, either based on historical samples or Monte Carlo methods.
Executive Summary: This deliverable identifies, analyzes and evaluates all possible data sources on FLOSS projects with special emphasis on data available for the next deliverables. Especially, repositories of FLOSS are discussed, then... more
Executive Summary: This deliverable identifies, analyzes and evaluates all possible data sources on FLOSS projects with special emphasis on data available for the next deliverables. Especially, repositories of FLOSS are discussed, then the main information sources versioning systems, mailing lists and bug tracing systems are described.
Zusammenfassung Im vorliegenden Artikel wird demonstriert, wie sich die Data Envelopment Analysis auf das Problemgebiet der Effizienzvergleiche von ERP-Einführungsprojekten anwenden läßt. Da die DEA ein nicht-parametrisches Verfahren für... more
Zusammenfassung Im vorliegenden Artikel wird demonstriert, wie sich die Data Envelopment Analysis auf das Problemgebiet der Effizienzvergleiche von ERP-Einführungsprojekten anwenden läßt. Da die DEA ein nicht-parametrisches Verfahren für den generellen Fall eines multi-Output, multi-Input Systems darstellt, ist sie für dieses Gebiet äußerst geeignet. Anhand von 39 ERP-Einführungsprojekten einer Fragebogenerhebung wird die DEA beispielhaft durchgeführt.
Software product lines have been proposed as a possible way of making software development more efficient. Borrowing from the main example of manufacturing, and melding these ideas with the classical approach of software reuse, software... more
Software product lines have been proposed as a possible way of making software development more efficient. Borrowing from the main example of manufacturing, and melding these ideas with the classical approach of software reuse, software product lines are large, industrial software systems intended to specialize into specific software products. This should lead to reduced costs, risks and time to market, as well as an increase in quality of the resulting products.
This paper develops models for programmer participation and effort estimation in open source software projects and employs the results to assess the efficiency of open source software creation. Successful development of such models will... more
This paper develops models for programmer participation and effort estimation in open source software projects and employs the results to assess the efficiency of open source software creation. Successful development of such models will be important for decision makers of various kinds. We propose hypotheses based on a prior case study on manpower function and effort modeling. A large data set retrieved from a project repository is used to test these hypotheses.
Abstract Libre (free, open source) software is one of the paradigmatic cases where heavy use of telematic tools and userdriven software development are key points. This paper proposes a methodology for measuring and analyzing remotely big... more
Abstract Libre (free, open source) software is one of the paradigmatic cases where heavy use of telematic tools and userdriven software development are key points. This paper proposes a methodology for measuring and analyzing remotely big libre software projects using publicly-available data from their version control repositories.
The present contribution proposes to transfer the main principles of open source software development to a new context: conceptual modelling; an activity closely related to software development. The goal of the proposed “open model”... more
The present contribution proposes to transfer the main principles of open source software development to a new context: conceptual modelling; an activity closely related to software development. The goal of the proposed “open model” approach is to collaboratively develop reference models for everyone to copy, use and refine in a public process.
Abstract: This paper makes the case for adopting a risk measure from the finance sector for the evaluation of e-Business projects and portfolios. The proposed value-at-risk method constitutes a well-tested approach in high-risk... more
Abstract: This paper makes the case for adopting a risk measure from the finance sector for the evaluation of e-Business projects and portfolios. The proposed value-at-risk method constitutes a well-tested approach in high-risk environments, especially banking, and reports the expected maximum loss (or worst loss) over a target horizon within a given confidence interval.
Erstellen Sie ein logisches Datenflussdiagramm für eine Diplomarbeitsbörse an einer Universität. Folgende Basisfunktionalität ist dabei zu beachten: Lehrende können Themen einbringen, die sich Studenten dann aussuchen und bearbeiten... more
Erstellen Sie ein logisches Datenflussdiagramm für eine Diplomarbeitsbörse an einer Universität. Folgende Basisfunktionalität ist dabei zu beachten: Lehrende können Themen einbringen, die sich Studenten dann aussuchen und bearbeiten können. Jedes Thema darf nur einmal vergeben werden. Studenten können ebenfalls Themen vorschlagen, die sie nach einer Prüfung durch einen Lehrenden bearbeiten können. Die Bearbeitung eines Themas kann beendet/abgebrochen werden, womit das Thema wieder frei wird.
Abstract: In dieser Arbeit wird ein Ansatz zu einem Aufwandsschätzungmodell für die Integration von Open Source Komponenten vorgestellt. Ausgehend von der Entwicklung einer Klassifikation unterschiedlicher Arten dieser Integration werden... more
Abstract: In dieser Arbeit wird ein Ansatz zu einem Aufwandsschätzungmodell für die Integration von Open Source Komponenten vorgestellt. Ausgehend von der Entwicklung einer Klassifikation unterschiedlicher Arten dieser Integration werden mögliche Operationalisierungen für die Evaluierung und darauf basierend die Aufwandsschätzung vorgeschlagen.
Abstract–In this paper, the evolution of a large sample of open source software projects will be analysed. The evolution of commercial systems has been an issue that has long been a center of research, thus a coherent theoretical... more
Abstract–In this paper, the evolution of a large sample of open source software projects will be analysed. The evolution of commercial systems has been an issue that has long been a center of research, thus a coherent theoretical framework of software evolution has been developed and empirically tested. Therefore these results can be used to compare the situation in open source projects to the evolution of commercial projects. This allows to assess whether the underlying software process indeed significantly differs.
This paper presents first results from research into open source projects from a software engineering perspective. The research methodology employed relies on public data retrieved from the CVS-repository of the GNOME project and relevant... more
This paper presents first results from research into open source projects from a software engineering perspective. The research methodology employed relies on public data retrieved from the CVS-repository of the GNOME project and relevant discussion groups. This methodology is described in detail and some of the results concerning the special characteristics of open source software development are given.(author's abstract)
In diesem Artikel werden die Ergebnisse einer vergleichenden Usability-Untersuchung von Office Suites dargestellt, wobei einerseits der kommerzielle Marktführer Microsoft Office, andererseits die in dem Bereich führende Open Source... more
In diesem Artikel werden die Ergebnisse einer vergleichenden Usability-Untersuchung von Office Suites dargestellt, wobei einerseits der kommerzielle Marktführer Microsoft Office, andererseits die in dem Bereich führende Open Source Software, OpenOffice. org, miteinbezogen wurden. Insbesondere sollte die Frage geklärt werden, ob und mit welchen Problemen ein Umstieg auf OpenOffice. org für Benutzer von Microsoft Office möglich ist.
Abstract OpenACS is a high-level community framework designed for developing collaborative Internet sites. It started from a university project at MIT, got momentum from the ArsDigita Foundation, and split up into a commercial and an open... more
Abstract OpenACS is a high-level community framework designed for developing collaborative Internet sites. It started from a university project at MIT, got momentum from the ArsDigita Foundation, and split up into a commercial and an open source version.
Abstract–Software development, and especially open source projects, typically involve repeated interactions between participants and groups of participants. We propose to analyse this situation by means of the standard model for the... more
Abstract–Software development, and especially open source projects, typically involve repeated interactions between participants and groups of participants. We propose to analyse this situation by means of the standard model for the evolution of cooperation, the iterated prisoner's dilemma.
Abstract This paper discusses in detail a possible methodology for collecting repository data on a large number of open source software projects from a single project hosting and community site. The process of data retrieval is described... more
Abstract This paper discusses in detail a possible methodology for collecting repository data on a large number of open source software projects from a single project hosting and community site. The process of data retrieval is described along with the possible metrics that can be computed and which can be used for further analyses. Example research areas to be addressed with the available data and first results are given.
In this paper, we propose to explore possible benefits of communication and coordination tools in open source projects using data envelopment analysis (DEA), a general method for efficiency comparisons.
Sin embargo, ya pesar de su creciente popularidad, persiste una comprensión muy pobre del SL. Quizás por causa de esta paradoja, durante los últimos años los investigadores han empezado a fijar su interés en el SL en sí mismo: sus modelos... more
Sin embargo, ya pesar de su creciente popularidad, persiste una comprensión muy pobre del SL. Quizás por causa de esta paradoja, durante los últimos años los investigadores han empezado a fijar su interés en el SL en sí mismo: sus modelos de desarrollo, el modelo de negocio que lo circunda, la motivación de los desarrolladores, etc.
In the last years an increasing number of enterprise resource planning (ERP) systems like SAP R/3, BaaN or Oracle Applications have been implemented. This implementation of the selected solution is risky and complex for individual... more
In the last years an increasing number of enterprise resource planning (ERP) systems like SAP R/3, BaaN or Oracle Applications have been implemented. This implementation of the selected solution is risky and complex for individual companies, since on the one hand the software and especially the necessary manpower is relatively expensive and on the other hand in this process possibly the internal business processes need to be adapted as well.
ABSTRACT In this paper we report possibilities and experiences from employing Counter-Strike, a popular multi-player Internet computer game and its resulting online community in research on cooperative behaviour. Advantages from using... more
ABSTRACT In this paper we report possibilities and experiences from employing Counter-Strike, a popular multi-player Internet computer game and its resulting online community in research on cooperative behaviour. Advantages from using this game include easy availability of rich data, the emphasis on team-playing, as well as numerous possibilities to change the experiment settings.
Free/Open Source Software gives an overview of the current research streams in the field of free and open source software development. A multitude of research approaches are used to explore free and open source software development... more
Free/Open Source Software gives an overview of the current research streams in the field of free and open source software development. A multitude of research approaches are used to explore free and open source software development processes, attributes of their products and the workings within the development communities.
Abstract In this paper, the evolution of a large sample of open source software systems will be analysed. The evolution of commercial systems has been an issue that has long been a centre of research, thus a coherent theoretical framework... more
Abstract In this paper, the evolution of a large sample of open source software systems will be analysed. The evolution of commercial systems has been an issue that has long been a centre of research, thus a coherent theoretical framework of software evolution has been developed and empirically tested, most notably the laws of software evolution.
In diesem Diskussionspapier wird die Entscheidungsfindung bei der Auswahl betriebswirtschaftlicher Standardsoftware mit Hilfe einer empirischen Studie untersucht. Zunächst wird anhand der Darstellung des Problemgebietes ein Einstieg in... more
In diesem Diskussionspapier wird die Entscheidungsfindung bei der Auswahl betriebswirtschaftlicher Standardsoftware mit Hilfe einer empirischen Studie untersucht. Zunächst wird anhand der Darstellung des Problemgebietes ein Einstieg in den Forschungsbereich gegeben und die verwendete Methodik sowie die in weiterer Folge untersuchten Fragestellungen vorgestellt.
Zusammenfassung Referenzmodelle sind ein zentraler Untersuchungsgegenstand der Wirtschaftsinformatik. Ihre Entwicklung ist nicht nur wissenschaftlich reizvoll, sie stellen gleichzeitig eine wirksame Unterstützung der Praxis in Aussicht.... more
Zusammenfassung Referenzmodelle sind ein zentraler Untersuchungsgegenstand der Wirtschaftsinformatik. Ihre Entwicklung ist nicht nur wissenschaftlich reizvoll, sie stellen gleichzeitig eine wirksame Unterstützung der Praxis in Aussicht. Diesen Verheißungen zum Trotz verlief die Entwicklung und–vor allem–Verbreitung wissenschaftlich fundierter Referenzmodelle bisher eher zurückhaltend.