Journal of Exposure Analysis and Environmental Epidemiology, 2002
The primary focus of this exposure assessment work involved developing an exposure model and dete... more The primary focus of this exposure assessment work involved developing an exposure model and determining a numerical point estimate of the amount of biologically relevant nitrate/nitrite exposure that occurred for each child in the study. This assessment was done in support of two epidemiological studies. The first study was an epidemiological cohort study (three cohorts based on nitrate/nitrite exposure) that explored the relationship between high nitrate/nitrite exposure and neuropsychological development. The second study was a nested case/control study (cases of methemoglobinemia versus disease-free controls) that sought to explore the relationship between MHG and various risk factors for the disease. This work uses both dietary survey and environmental sampling and modeling in order to develop two point estimates of nitrate exposure in milligrams per kilogram per day of nitrite (the biologically active form of the hemoglobin-oxidizing agent) for the first 6 months of the child's life (2-months-of-age and 6-months-of-age point estimates). Methodologies included proxy interviews of primary caregivers, review of existing medical and environmental sampling and analysis. Exposure to nitrate--nitrogen (with final calculations converted to the biologically active form of the toxin, nitrite) was categorized as high, medium, and low as determined from the distribution of the data derived from final exposure calculations at both the 2-months-of-age point estimate and at the 6-months-of-age point estimate. These tertiles correspond to greater-than-or-equal1.5 mg/kg/day nitrite-nitrogen for high-exposure individuals, <1.5-> or = 0.1 mg/kg/day for medium-exposure individuals, and <0.1 mg/kg/day for low-exposure individuals. Analyses illustrate that over 90% of the nitrate exposure occurred through the consumption of liquids (water) at the 2-months-of-age point estimate while at the 6-months-of-age point estimate, a 10-fold change in the amount of solid consumables occurred. Final exposure calculations were well differentiated into three tertiles based on a point estimate of average daily intake of nitrite in milligrams per kilogram body weight per day at roughly 2 and 6 months of age. These categories of exposure, based on the exposure model point estimate, correspond well with the exposure estimates as estimated only on the basis of cohort status and their corresponding nitrate/nitrite well water levels. Comparisons of these two sets of data illustrate that following the MHG incident, Cohort II shifted places with Cohort I to become the high-exposure cohort. Further, the predictive ability of the exposure assessment in regard to the outcome of MHG was estimated using a Likelihood Ratio and Pearson's Crosstab analysis. This was performed on the 2-month-of-age point estimate. Likelihood Ratio and Pearson's chi-square were 39.40 and 33.74, respectively, with a probability of achieving these fits by chance alone of <0.0001. This indicates clearly that the children who experienced MHG were also the children at the 2-month-of-age point estimate who had received the highest exposure to nitrate/nitrite through their diet.
Hepatocellular carcinoma is one of the most common malignant tumors that carry a poor prognosis. ... more Hepatocellular carcinoma is one of the most common malignant tumors that carry a poor prognosis. To improve the long-term outlook for HCC, an accurate prognosis is important. To study the immunohistochemical expressions of p53, Ki67, Bcl-2, VEGF and PCNA and their potential role as prognostic factors in patients with radical resection of hepatocellular carcinoma. Forty-seven formalin-fixed paraffin-embedded tumor samples from patients with HCC receiving liver resection were investigated immunohistochemically for the expression of cellular proliferation markers PCNA, Ki67, p53, Bcl-2 and VEGF and their correlation with tumor characteristics and survival time after resection. p53 was expressed in a higher percentage (85.7 vs. 42.1%) in undifferentiated histological tumor grades (Edmondson Steiner G3/G4 vs. G1/G2). Patients with p53 accumulating tumors showed a worse survival than patients with p53 non-accumulating tumors (median 9.5 vs. 16.5 months). Over-expression of VEGF was found in 38.3% of all HCCs. VEGF expression was significantly correlated with p53 expression and recurrence rates. The results showed that the labeling index of PCNA and expression of p53 are correlated. The high labeling index of PCNA or over-expression of p53 resulted in high risk of tumor recurrence, more aggressive growth and poor survival. High labeling index of PCNA, p53 nuclear accumulation and VEGF high expression are associated with poor survival in patients with HCC.
The histopathological classification of gastric cancer is a complex and difficult task. The main ... more The histopathological classification of gastric cancer is a complex and difficult task. The main impediment is the heterogeneity of this tumors, frequently underestimated in clinicopathological research. Fractal geometry may help to explain this heterogeneity. In order to investigate the relationship between the complexity of the epithelial/connective interface (as determined by fractal dimension) and the malignancy of the gastric tumor we
The oviduct is known to secrete mucins (MUC1 and MUC9) under the influence of ovarian steroids. T... more The oviduct is known to secrete mucins (MUC1 and MUC9) under the influence of ovarian steroids. The secreted form of MUC1 binds gametes in the oviduct, whereas the cellular form seen in breast cancers has been implicated in cell adhesion and morphogenesis. The secreted MUC9 or oviduct-specific glycoprotein (OGP), in addition to being a mucin, belongs to family 18 glycosylhydrolases and is known to bind gametes and embryos in the oviduct. Studies in our laboratory have identified non-muscle myosin IIA (involved in cell shape, polarity, and morphogenesis) as the protein partner to OGP in gametes. In view of the crucial role of the cortical cytoskeleton in the selective internalization of tight junctions (TJs) /adherent junctions (AJs) or apical junctional complex (AJC) in simple epithelial cells during tissue remodeling, the present study has been undertaken to evaluate the existence of a cellular form of OGP in oviductal tissue, which itself undergoes cyclic tissue remodeling. In silico analysis of the deduced amino-acid sequence of OGP has revealed the presence of several conserved motifs; these imply that OGP is a component of multi-protein complexes such as TJs. Corroborative immunoelectron-microscopic analysis in peri-ovulatory oviduct epithelia in the bonnet monkey has revealed the presence of OGP at the TJ. Co-localization studies of OGP and cadherin demonstrate that, whereas OGP is localized at the tonofilaments of the TJs, cadherin is localized at the intercellular space of the AJ. The possible role of OGP in oviductal tissue remodeling is discussed in light of the present findings and those reported in the literature.
We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-deca... more We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-decays to the dimuon data set acquired with the CDF detector. Based on this improved estimate, we show that the total number and the properties of the collected dimuon events are not yet accounted for by ordinary sources of dimuons which also include the contributions, as measured in the data, of heavy flavor, ϒ, and Drell–Yan production in addition to muons mimicked by hadronic punchthrough. The number of unaccounted events corresponds to (12.8±3.2)% of the $b\bar{b}$ production. We find that (23±6)% of the unaccounted events contain additional muon candidates. For comparison, this fraction is (6.9±0.4)% for events due to $b\bar{b}$ production.
One of the goals of the “Language Technology for LifeLong Learning” project is the creation of an... more One of the goals of the “Language Technology for LifeLong Learning” project is the creation of an appropriate methodology to support both formal and informal learning. Services are being developed that are based on the interaction between a formal representation of (domain) knowledge in the form of an ontology created by experts and a social component which complements it, that is tags and social networks. It is expected that this combination will improve learner interaction, knowledge discovery as well as knowledge co-construction.
Intense near-infrared pulses comprising a few wave cycles centred around 800 nm had became routin... more Intense near-infrared pulses comprising a few wave cycles centred around 800 nm had became routinely available by the turn of the millennium. They have been instrumental in controlled generation of atto-second pulses of extreme ultraviolet light, both single and pulse trains, opening the door to real-time observation of atomic-scale electron dynamics. Attosecond pulses of light are generated by first producing attosecond electron pulses during strong-field ionization of atoms or molecules. These electron pulses offer new opportunities for imaging structures with femtosecond temporal and sub-Angstrom spatial resolution. In this article we look at how these new opportunities might be influenced by the new generation of intense, few-cycle mid-infrared sources with wavelengths in 2 to 3 μm range.
Journal of Exposure Analysis and Environmental Epidemiology, 2002
The primary focus of this exposure assessment work involved developing an exposure model and dete... more The primary focus of this exposure assessment work involved developing an exposure model and determining a numerical point estimate of the amount of biologically relevant nitrate/nitrite exposure that occurred for each child in the study. This assessment was done in support of two epidemiological studies. The first study was an epidemiological cohort study (three cohorts based on nitrate/nitrite exposure) that explored the relationship between high nitrate/nitrite exposure and neuropsychological development. The second study was a nested case/control study (cases of methemoglobinemia versus disease-free controls) that sought to explore the relationship between MHG and various risk factors for the disease. This work uses both dietary survey and environmental sampling and modeling in order to develop two point estimates of nitrate exposure in milligrams per kilogram per day of nitrite (the biologically active form of the hemoglobin-oxidizing agent) for the first 6 months of the child's life (2-months-of-age and 6-months-of-age point estimates). Methodologies included proxy interviews of primary caregivers, review of existing medical and environmental sampling and analysis. Exposure to nitrate--nitrogen (with final calculations converted to the biologically active form of the toxin, nitrite) was categorized as high, medium, and low as determined from the distribution of the data derived from final exposure calculations at both the 2-months-of-age point estimate and at the 6-months-of-age point estimate. These tertiles correspond to greater-than-or-equal1.5 mg/kg/day nitrite-nitrogen for high-exposure individuals, <1.5-> or = 0.1 mg/kg/day for medium-exposure individuals, and <0.1 mg/kg/day for low-exposure individuals. Analyses illustrate that over 90% of the nitrate exposure occurred through the consumption of liquids (water) at the 2-months-of-age point estimate while at the 6-months-of-age point estimate, a 10-fold change in the amount of solid consumables occurred. Final exposure calculations were well differentiated into three tertiles based on a point estimate of average daily intake of nitrite in milligrams per kilogram body weight per day at roughly 2 and 6 months of age. These categories of exposure, based on the exposure model point estimate, correspond well with the exposure estimates as estimated only on the basis of cohort status and their corresponding nitrate/nitrite well water levels. Comparisons of these two sets of data illustrate that following the MHG incident, Cohort II shifted places with Cohort I to become the high-exposure cohort. Further, the predictive ability of the exposure assessment in regard to the outcome of MHG was estimated using a Likelihood Ratio and Pearson's Crosstab analysis. This was performed on the 2-month-of-age point estimate. Likelihood Ratio and Pearson's chi-square were 39.40 and 33.74, respectively, with a probability of achieving these fits by chance alone of <0.0001. This indicates clearly that the children who experienced MHG were also the children at the 2-month-of-age point estimate who had received the highest exposure to nitrate/nitrite through their diet.
Hepatocellular carcinoma is one of the most common malignant tumors that carry a poor prognosis. ... more Hepatocellular carcinoma is one of the most common malignant tumors that carry a poor prognosis. To improve the long-term outlook for HCC, an accurate prognosis is important. To study the immunohistochemical expressions of p53, Ki67, Bcl-2, VEGF and PCNA and their potential role as prognostic factors in patients with radical resection of hepatocellular carcinoma. Forty-seven formalin-fixed paraffin-embedded tumor samples from patients with HCC receiving liver resection were investigated immunohistochemically for the expression of cellular proliferation markers PCNA, Ki67, p53, Bcl-2 and VEGF and their correlation with tumor characteristics and survival time after resection. p53 was expressed in a higher percentage (85.7 vs. 42.1%) in undifferentiated histological tumor grades (Edmondson Steiner G3/G4 vs. G1/G2). Patients with p53 accumulating tumors showed a worse survival than patients with p53 non-accumulating tumors (median 9.5 vs. 16.5 months). Over-expression of VEGF was found in 38.3% of all HCCs. VEGF expression was significantly correlated with p53 expression and recurrence rates. The results showed that the labeling index of PCNA and expression of p53 are correlated. The high labeling index of PCNA or over-expression of p53 resulted in high risk of tumor recurrence, more aggressive growth and poor survival. High labeling index of PCNA, p53 nuclear accumulation and VEGF high expression are associated with poor survival in patients with HCC.
The histopathological classification of gastric cancer is a complex and difficult task. The main ... more The histopathological classification of gastric cancer is a complex and difficult task. The main impediment is the heterogeneity of this tumors, frequently underestimated in clinicopathological research. Fractal geometry may help to explain this heterogeneity. In order to investigate the relationship between the complexity of the epithelial/connective interface (as determined by fractal dimension) and the malignancy of the gastric tumor we
The oviduct is known to secrete mucins (MUC1 and MUC9) under the influence of ovarian steroids. T... more The oviduct is known to secrete mucins (MUC1 and MUC9) under the influence of ovarian steroids. The secreted form of MUC1 binds gametes in the oviduct, whereas the cellular form seen in breast cancers has been implicated in cell adhesion and morphogenesis. The secreted MUC9 or oviduct-specific glycoprotein (OGP), in addition to being a mucin, belongs to family 18 glycosylhydrolases and is known to bind gametes and embryos in the oviduct. Studies in our laboratory have identified non-muscle myosin IIA (involved in cell shape, polarity, and morphogenesis) as the protein partner to OGP in gametes. In view of the crucial role of the cortical cytoskeleton in the selective internalization of tight junctions (TJs) /adherent junctions (AJs) or apical junctional complex (AJC) in simple epithelial cells during tissue remodeling, the present study has been undertaken to evaluate the existence of a cellular form of OGP in oviductal tissue, which itself undergoes cyclic tissue remodeling. In silico analysis of the deduced amino-acid sequence of OGP has revealed the presence of several conserved motifs; these imply that OGP is a component of multi-protein complexes such as TJs. Corroborative immunoelectron-microscopic analysis in peri-ovulatory oviduct epithelia in the bonnet monkey has revealed the presence of OGP at the TJ. Co-localization studies of OGP and cadherin demonstrate that, whereas OGP is localized at the tonofilaments of the TJs, cadherin is localized at the intercellular space of the AJ. The possible role of OGP in oviductal tissue remodeling is discussed in light of the present findings and those reported in the literature.
We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-deca... more We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-decays to the dimuon data set acquired with the CDF detector. Based on this improved estimate, we show that the total number and the properties of the collected dimuon events are not yet accounted for by ordinary sources of dimuons which also include the contributions, as measured in the data, of heavy flavor, ϒ, and Drell–Yan production in addition to muons mimicked by hadronic punchthrough. The number of unaccounted events corresponds to (12.8±3.2)% of the $b\bar{b}$ production. We find that (23±6)% of the unaccounted events contain additional muon candidates. For comparison, this fraction is (6.9±0.4)% for events due to $b\bar{b}$ production.
One of the goals of the “Language Technology for LifeLong Learning” project is the creation of an... more One of the goals of the “Language Technology for LifeLong Learning” project is the creation of an appropriate methodology to support both formal and informal learning. Services are being developed that are based on the interaction between a formal representation of (domain) knowledge in the form of an ontology created by experts and a social component which complements it, that is tags and social networks. It is expected that this combination will improve learner interaction, knowledge discovery as well as knowledge co-construction.
Intense near-infrared pulses comprising a few wave cycles centred around 800 nm had became routin... more Intense near-infrared pulses comprising a few wave cycles centred around 800 nm had became routinely available by the turn of the millennium. They have been instrumental in controlled generation of atto-second pulses of extreme ultraviolet light, both single and pulse trains, opening the door to real-time observation of atomic-scale electron dynamics. Attosecond pulses of light are generated by first producing attosecond electron pulses during strong-field ionization of atoms or molecules. These electron pulses offer new opportunities for imaging structures with femtosecond temporal and sub-Angstrom spatial resolution. In this article we look at how these new opportunities might be influenced by the new generation of intense, few-cycle mid-infrared sources with wavelengths in 2 to 3 μm range.
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Papers by Vlad Ivanov