CREST

Objectives: To describe the differences in bone healing, when placing four different implant systems in fresh extraction sockets.Material and Methods: Eight beagle dogs received implants randomly installed into the distal socket of three P3 and four P4. Four-implant systems were evaluated. Each animal provided four test implant sites. All animals were sacrificed at 6 weeks after implant placement, providing specimens for histo-morphometric analysis of bone to implant contact (BIC), bone area, new bone formation, as well as histometric measurements of the ridge alterations.Results: No statistically significant difference was observed among the four-implant systems. The mean BIC % ranged between 58.5% and 72.1%. Bone modelling of the buccal plate was marked and amounted approximately to 2.5 mm, independently of the system used.Conclusion: This study failed to demonstrate differences in the healing pattern after 6 weeks when placing four different implant systems in fresh extraction sockets. In spite of achieving predictable osteointegration with the four implants studied, the occurrence of buccal bone resorption may limit the use of this surgical approach.

de Sanctis M, Vignoletti F, Discepoli N, Muñoz F, Sanz M. Immediate implants at fresh extraction sockets: an experimental study in the beagle dog comparing four different implant systems. Soft tissue findings. J Clin Periodontol 2010; 37: 769-776 doi: 10.1111/j.1600-051X.2010.01570.x.de Sanctis M, Vignoletti F, Discepoli N, Muñoz F, Sanz M. Immediate implants at fresh extraction sockets: an experimental study in the beagle dog comparing four different implant systems. Soft tissue findings. J Clin Periodontol 2010; 37: 769-776 doi: 10.1111/j.1600-051X.2010.01570.x.AbstractObjectives: To evaluate whether different implants placed immediately upon tooth extraction may affect the dimension and composition of the peri-implant soft tissues.Material and Methods: Eight beagle dogs received implants randomly installed into the distal socket of 3P3 and 4P4. Four commercially available implant systems were evaluated: 3i Osseotite Certain straight; Astra MicroThread™-OsseoSpeed™; Thommen SPI Element®; and Straumann ITI standard. Each animal provided four test implant sites. All animals were sacrificed 6 weeks after implant placement, providing specimens for the evaluation of the soft tissue dimensions by histometric analysis.Results: The biological width at 6 weeks after implant placement consisted of a junctional epithelium measuring between 2 and 2.7 mm and a connective tissue component between 1 and 1.8 mm with no statistical differences among the four implant systems.Conclusion: This study failed to demonstrate differences in the soft tissue healing outcome when placing four different implant systems into fresh extraction sockets. Nevertheless, the length of the epithelium achieved with the four implant systems is longer than what has been reported when placing implants in healed-ridge experimental models.Objectives: To evaluate whether different implants placed immediately upon tooth extraction may affect the dimension and composition of the peri-implant soft tissues.Material and Methods: Eight beagle dogs received implants randomly installed into the distal socket of 3P3 and 4P4. Four commercially available implant systems were evaluated: 3i Osseotite Certain straight; Astra MicroThread™-OsseoSpeed™; Thommen SPI Element®; and Straumann ITI standard. Each animal provided four test implant sites. All animals were sacrificed 6 weeks after implant placement, providing specimens for the evaluation of the soft tissue dimensions by histometric analysis.Results: The biological width at 6 weeks after implant placement consisted of a junctional epithelium measuring between 2 and 2.7 mm and a connective tissue component between 1 and 1.8 mm with no statistical differences among the four implant systems.Conclusion: This study failed to demonstrate differences in the soft tissue healing outcome when placing four different implant systems into fresh extraction sockets. Nevertheless, the length of the epithelium achieved with the four implant systems is longer than what has been reported when placing implants in healed-ridge experimental models.

Crete is considered as a semi-arid region. The average annual precipitation is estimated to be 900 mm, the potential renewable water resources 2650 and the real water used about 485 million m3/yr. The major water use in Crete is in irrigation for agriculture (84.5% of the total ...

Objectives: Describe the early phases of tissue integration in implants placed into fresh extraction sockets and test whether a new implant surface nano-topography (DCD nano-particles, Nanotite™) promotes early osseointegration when compared with minimally rough surface implants (DAE, Osseotite®).Material and Methods: Sixteen beagle dogs received 64 test and control implants randomly installed into the distal socket of 3P3 and 4P4. Histomorphometric analysis of bone to implant contact (BIC) and bone area was performed at 4 h, 1, 2, 4 and 8 weeks.Results: Wound healing initiated with a coagulum that was substituted by a provisional matrix at 1 week. Bone formation started concomitant to a marked bone resorption. At 2 weeks, woven bone formation was evident and gradually remodelled into lamellar bone at 4 and 8 weeks. BIC increased similarly throughout the study in both groups with a tendency to higher percentages for the test devices at 2 and 4 weeks. The influence of the DCD nano-particles was more evident at the fourth premolar site.Conclusion: Osseointegration occurred similarly at both implant groups, although the socket dimension appeared to influence bone healing. It is suggested that the enhanced nano-topography has a limited effect in the immediate implant surgical protocol.

Aims: To describe the early phases of healing at the alveolar ridge around dental implants placed into fresh extraction sockets and to study whether (i) the dimension of the socket and (ii) a new implant surface nano-topography may have any influence.Materials and Methods: Sixteen beagle dogs received 64 test (new surface) and control implants randomly placed at the distal socket of 3P3 and 4P4. The implant shoulder was levelled with the marginal buccal bone crest. Animals were sacrificed at 4 h, 1, 2, 4 and 8 weeks for histological examination.Results: Bone loss occurred at the buccal crest between the 4-h and 1-week healing intervals, being more pronounced at the third premolar site [vertical bone loss between day 0 and 8 weeks 1.1 (0.5) mm]. The corresponding loss at the fourth premolar site was 0.3 (0.5) mm. Test sites containing implants with discrete crystalline deposition nano-particles' surface exhibited less buccal bone resorption than control sites at 8 weeks.Conclusion: Dimensions of the socket influenced the process of wound healing of implants placed into fresh extraction sockets, with more bone loss in the narrower sockets; however, the implant surface nano-topography seemed to have a limited effect in the healing of this implant surgical protocol.

The field of quantitative palaeoclimatology has made significant progress in the past decades. However, this progress has been spatially heterogeneous and strong discrepancies – both in terms of quality and density – exist between Europe and North America and the rest of the world. The need to balance this distribution of quantified records has never been stronger, and improving our understanding of past global climate is urgent in order to better evaluate and employ the predictions of climate models. In this paper, it is argued that this gap can be reduced by applying the climate reconstruction method CREST (Climate REconstruction SofTware) calibrated using the open-access GBIF (Global Biodiversity Information Facility) database, which contains hundreds of thousands modern distributions of numerous bio-indicator proxies (e.g. pollen, chironomids, foraminifers, etc.). Using the taxonomical diversity of the GBIF database, CREST can be used to reconstruct various climate and/or environmental parameters from assemblage variety of different records. Independent from the usual re- construction techniques using surface samples for calibration, the CREST/GBIF framework can also be used as an independent tool that can be easily and efficiently applied (1) to complete the global coverage of climate re- constructions, as exemplified with a precipitation reconstruction from Lake Van, Turkey, (2) to revisit existing data sets to obtain new quantitative reconstructions, and (3) to evaluate and/or refine reconstructions based on other methods. The application of this tool promises to foster advances in our understanding of the past climate variability of the Earth system at a global scale.

Aim: To describe histologically the early phases of soft tissue healing to implants placed into fresh extraction sockets.Materials and Methods: In 16 beagle dogs, 64 3.25-mm-wide cylindrical screw implants were inserted into the distal sockets of the third and fourth lower premolars using a one-stage trans-mucosal healing protocol. Biopsies were then taken at 1, 2, 4 and 8 weeks and prepared for histological examination.Results: One-week specimens showed a junctional epithelium and an underlying loose connective tissue rich in inflammatory cells. At 2 weeks, signs of epithelial proliferation and a more organized connective tissue were observed. At 4 and 8 weeks, inflammation was absent; the epithelium appeared mature and in close contact with the surface of the healing abutment or the implant. The connective tissue was dense in an area close to the implant surface and the fibres were aligned parallel to the implant surface. The soft tissue dimensions at 8 weeks were approximately 5 mm, including about 3–3.5 mm of epithelium and 1–1.5 mm of connective tissue.Conclusion: Soft tissue healing to implants placed in fresh extraction sockets may result in a longer epithelial interface than implants placed in a healed ridge.

The American Association of State Highway and Transportation Officials (AASHTO) presents general controls for the combination of horizontal and vertical alignments. Excellence in alignment coordination enhances safety, operation, and appearance. This paper quantifies one of the AASHTO general controls that is related to introducing a horizontal curve at or near the top of a crest vertical curve. It establishes the locations where a horizontal curve should not start in relation to a vertical curve because the available sight distance is less than (1) the stopping-sight distance (SSD); or (2) the preview sight distance (PVSD) that allows the driver to detect the horizontal curve and react properly and comfortably. The range of these locations, called the red zone, is established for a selected alignment using three-dimensional (3D) analysis of sight distance. Both daytime and nighttime cases are discussed. The sensitivity of the red zones for PVSD to the superelevation rate, turning direction of horizontal curve, vertical curvature, and spiral curves is examined. The effect of spiral curves and location of cut slopes on the red zone for daytime SSD is also examined. This paper shows how 3D analysis can be used to identify red zones for existing combined alignments or to avoid them for new alignments. As such, it should be of interest to the design engineers concerned with highway safety.

Statistical approaches for studying the spatial distribution of genetic diversity that assume that organisms move through a two-dimensional landscape are not well suited to study populations of freshwater fish. We present a new statistical method for mapping genetic differences among populations of freshwater fish to the sections of streams that connect them. The method is useful for freshwater species that can only disperse through stream corridors and for other species that live in habitats for which there is one, and only one, corridor connecting each pair of populations (e.g., alpine organisms confined to ridge tops). The model is a simple extension of the least-squares method for constructing evolutionary trees. In this model, the genetic distances between populations are modeled as a sum of genetic distances mapped onto landscape features (e.g., stream sections). Analysis of simulated data shows that the method produces useful results with realistic amounts of data. The model ...

The material investigated in this study is automotive grey cast iron (SAE G-3500) used for the manufacture of cylinder liners in a range of diesel engines. A comprehensive model for the understanding of wear and friction of this type of materials is presented here for the first time. This model takes into account the cumulative contribution of various mechanisms of wear and friction (truncation, adhesion, delamination and ploughing) to the overall phenomenon of wear loss. Quantitative aspects and statistical modelling were employed to develop a mathematical relationship between measurements of friction and wear under varying conditions of load, number of cycles and velocity (rev min−1).

The Coupled Routing and Excess STorage model (CREST, jointly developed by the University of Oklahoma and NASA SERVIR) is a distributed hydrological model developed to simulate the spatial and temporal variation of land surface, and subsurface water fluxes and storages by cell-to-cell simulation. CREST's distinguishing characteristics include: (1) distributed rainfall–runoff generation and cell-to-cell routing; (2) coupled runoff generation and routing via three feedback mechanisms; and (3) representation of sub-grid cell variability of soil moisture storage capacity and sub-grid cell routing (via linear reservoirs). The coupling between the runoff generation and routing mechanisms allows detailed and realistic treatment of hydrological variables such as soil moisture. Furthermore, the representation of soil moisture variability and routing processes at the sub-grid scale enables the CREST model to be readily scalable to multi-scale modelling research. This paper presents the model development and demonstrates its applicability for a case study in the Nzoia basin located in Lake Victoria, Africa. Citation Wang, J., Yang, H., Li, L., Gourley, J. J., Sadiq, I. K., Yilmaz, K. K., Adler, R. F., Policelli, F. S., Habib, S., Irwn, D., Limaye, A. S., Korme, T. & Okello, L. (2011) The coupled routing and excess storage (CREST) distributed hydrological model. Hydrol. Sci. J. 56(1), 84–98.Le modèle couplé routage et stockage des excédents (CREST, développé conjointement par l'Université de l'Oklahoma et NASA SERVIR) est un modèle hydrologique distribué développé pour simuler les variations spatiales et temporelles des flux d'eau de surface et souterraine ainsi que les stockages, par simulation de cellule à cellule. Les caractéristiques distinctives de CREST sont les suivantes: (1) production pluie–débit distribuée et routage de cellule à cellule; (2) couplage de la production et du routage du ruissellement via trois mécanismes de rétroaction; et (3) représentation de la variabilité sub-cellulaire de la capacité de stockage en eau du sol et du routage infra-cellulaire (via des réservoirs linéaires). Le couplage entre la genèse du ruissellement et les mécanismes de routage permet un traitement détaillé et réaliste des variables hydrologiques telles que l'humidité du sol. En outre, la représentation de la variabilité de l'humidité du sol et des processus de routage à l'échelle sub-cellulaire permet au modèle CREST d'être facilement étendu à la recherche sur la modélisation multi-échelles. Cet article présente le développement du modèle et démontre son applicabilité pour une étude de cas dans le bassin de la Nzoia, Lac Victoria, Afrique.