642 research outputs found

    QSPR Modeling of Bioconcentration Factors of Nonionic Organic Compounds

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    The terms bioaccumulation and bioconcentration refer to the uptake and build-up of chemicals that can occur in living organisms. Experimental measurement of bioconcentration is time-consuming and expensive, and is not feasible for a large number of chemicals of potential regulatory concern. A highly effective tool depending on a quantitative structure-property relationship (QSPR) can be utilized to describe the tendency of chemical concentration organisms represented by, the important ecotoxicological parameter, the logarithm of Bio Concentration Factor (log BCF) with molecular descriptors for a large set of non-ionic organic compounds. QSPR models were developed using multiple linear regression, partial least squares and neural networks analyses. Linear and non-linear QSPR models to predict log BCF of the compounds developed for the relevant descriptors. The results obtained offer good regression models having good prediction ability. The descriptors used in these models depend on the volume, connectivity, molar refractivity, surface tension and the presence of atoms accepting H-bonds

    Quantum Chemical QSAR Models to Distinguish Between Inhibitory Activities of Sulfonamides Against Human Carbonic Anhydrases I and II and Bovine IV Isozymes

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    Linear and nonlinear quantitative structure activity relationship models for predicting the inhibitory activities of sulfonamides toward different carbonic anhydrase isozymes were developed based on multilinear regression, principal component-artificial neural network and correlation ranking-principal component analysis, to identify a set of structurally based numerical descriptors. Multilinear regression was used to build linear quantitative structure activity relationship models using 53 compounds with their quantum chemical descriptors. For each type of isozyme, separate quantitative structure activity relationship models were obtained. It was found that the hydration energy plays a significant role in the binding of ligands to the CAI isozyme, whereas the presence of five-membered ring was detected as a major factor for the binding to the CAII isozyme. It was also found that the softness exhibited significant effect on the binding to CAIV isozyme. Principal component-artificial neural network and correlation ranking-principal component analysis analyses provide models with better prediction capability for the three types of the carbonic anhydrase isozyme inhibitory activity than those obtained by multilinear regression analysis. The best models, with improved prediction capability, were obtained for the hCAII isozyme activity. Models predictivity was evaluated by cross-validation, using an external test set and chance correlation test

    Use of high throughput sequencing to observe genome dynamics at a single cell level

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    With the development of high throughput sequencing technology, it becomes possible to directly analyze mutation distribution in a genome-wide fashion, dissociating mutation rate measurements from the traditional underlying assumptions. Here, we sequenced several genomes of Escherichia coli from colonies obtained after chemical mutagenesis and observed a strikingly nonrandom distribution of the induced mutations. These include long stretches of exclusively G to A or C to T transitions along the genome and orders of magnitude intra- and inter-genomic differences in mutation density. Whereas most of these observations can be explained by the known features of enzymatic processes, the others could reflect stochasticity in the molecular processes at the single-cell level. Our results demonstrate how analysis of the molecular records left in the genomes of the descendants of an individual mutagenized cell allows for genome-scale observations of fixation and segregation of mutations, as well as recombination events, in the single genome of their progenitor.Comment: 22 pages, 9 figures (including 5 supplementary), one tabl

    Onset of human preterm and term birth is related to unique inflammatory transcriptome profiles at the maternal fetal interface.

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    BackgroundPreterm birth is a main determinant of neonatal mortality and morbidity and a major contributor to the overall mortality and burden of disease. However, research of the preterm birth is hindered by the imprecise definition of the clinical phenotype and complexity of the molecular phenotype due to multiple pregnancy tissue types and molecular processes that may contribute to the preterm birth. Here we comprehensively evaluate the mRNA transcriptome that characterizes preterm and term labor in tissues comprising the pregnancy using precisely phenotyped samples. The four complementary phenotypes together provide comprehensive insight into preterm and term parturition.MethodsSamples of maternal blood, chorion, amnion, placenta, decidua, fetal blood, and myometrium from the uterine fundus and lower segment (n = 183) were obtained during cesarean delivery from women with four complementary phenotypes: delivering preterm with (PL) and without labor (PNL), term with (TL) and without labor (TNL). Enrolled were 35 pregnant women with four precisely and prospectively defined phenotypes: PL (n = 8), PNL (n = 10), TL (n = 7) and TNL (n = 10). Gene expression data were analyzed using shrunken centroid analysis to identify a minimal set of genes that uniquely characterizes each of the four phenotypes. Expression profiles of 73 genes and non-coding RNA sequences uniquely identified each of the four phenotypes. The shrunken centroid analysis and 10 times 10-fold cross-validation was also used to minimize false positive finings and overfitting. Identified were the pathways and molecular processes associated with and the cis-regulatory elements in gene's 5' promoter or 3'-UTR regions of the set of genes which expression uniquely characterized the four phenotypes.ResultsThe largest differences in gene expression among the four groups occurred at maternal fetal interface in decidua, chorion and amnion. The gene expression profiles showed suppression of chemokines expression in TNL, withdrawal of this suppression in TL, activation of multiple pathways of inflammation in PL, and an immune rejection profile in PNL. The genes constituting expression signatures showed over-representation of three putative regulatory elements in their 5'and 3' UTR regions.ConclusionsThe results suggest that pregnancy is maintained by downregulation of chemokines at the maternal-fetal interface. Withdrawal of this downregulation results in the term birth and its overriding by the activation of multiple pathways of the immune system in the preterm birth. Complications of the pregnancy associated with impairment of placental function, which necessitated premature delivery of the fetus in the absence of labor, show gene expression patterns associated with immune rejection

    Lie symmetry and μ-symmetry methods for nonlinear generalized Camassa–Holm equation

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    Abstract In this paper, a Lie symmetry method is used for the nonlinear generalized Camassa–Holm equation and as a result reduction of the order and computing the conservation laws are presented. Furthermore, μ-symmetry and μ-conservation laws of the generalized Camassa–Holm equation are obtained

    Bone mineral density is lower in male than female patients with plaque-type psoriasis in Iran

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    Background There are many similarities with regard to contributing cytokines in patients with psoriasis and osteoporosis. A theory of probable relationship between these two entities has been proposed but there is no concordant consensus. The aim of this study was to evaluate bone mineral density (BMD) in patients with psoriasis. Method and materials This cross-sectional study of BMD was conducted with 64 eligible patients with psoriasis who were referred to the dermatology clinic of Razi hospital in Tehran, Iran in between 2011 and 2012. Results The mean T score of femoral neck was �1.17 and �0.49 in men and women, respectively, which was statistically significant (p =.047). The mean T score of the lumbar spine was �0.93 and �0.30 in men and women, respectively, but not statistically significant (p =.058). In total except with the exclusion of the study site (femur or lumbar), men and women did not have a statistically significant difference with regard to osteoporosis or osteopenia in BMD (p =.114). The Pearson correlation coefficient demonstrated a moderate inverse relationship between age and T score of the femoral neck and lumbar spine (r = �0.419 and �.406, respectively), which was statistically significant (p =.001). Although there was no statistically significant relationship between the Psoriasis Area and Severity Index (PASI) and T scores of the femoral neck (p =.596), a positive and weak correlation was observed between the PASI and T scores for the lumbar spine, which was statistically significant (r = 0.269; p =.03). Conclusion Patients with psoriasis had decreased bone density, which was more significant in men. Prevalence of osteoporosis showed no statistically significant difference when compared with the healthy population in Iran. © 201

    Incidence of self-reported interpersonal violence related physical injury in Iran

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    Background: Violence is the cause of death for 1.5 million people in a year. Objectives: Our study aimed to estimate the incidence rate of self-reported interpersonal violence related physical injury (VRPI) and its associated factors in Iran. Patients and Methods: The sample included people ranged from 15 to 64 years old who were residing in Iran. A total of 1525 clusters were selected from the whole country. Six families were selected from each cluster via a systematic random sampling method. Then, the residential units were identified and the interviewers contacted the inhabitants. In the next step, one of the family members was selected by using Kish grid method. The instrument was a researcher-made questionnaire and consisted of two sections; demographics and project related data. Face validity and content validity of our questionnaire were investigated based on expert opinions and the reliability was confirmed by a pilot study, as well. The inclusion criteria were considered for choosing the interviewers. An interviewer was assigned for each 42 participants (7 clusters). An educational seminar was held for the administrative managers (54 persons) and interviewers (230 persons) for a week. The field work was distributed among all 46 Medical Sciences universities in Iran. In each university, administrative issues were related to an executive director. Mann-Whitney U test and odds ratio were used to analyze the data with 95 confidence interval. α value was considered less than 5. Results: The frequency of VRPI among 7886 participants was 24 during the last three months. The incidence rate of interpersonal VRPI was estimated at 3.04 per 1000 population (95 CI: 2.66-3.42) during a three-month interval in Iran. The incidence was 4.72 per 1000 population (95 CI: 4.01-5.43) for males and 1.78 per 1000 population (95 CI: 1.39-2.17) for females during a three-month interval. The mean (SD) of age of the participants with and without a history of VRPI were 26.5 (7.21) and 33.05 (12.05) years, respectively (P = 0.008). Considering the participants� gender, 66.7 were males (OR = 2.66, 95 CI: 1.14-6.23). Khuzestan Province had the most VRPIs (25 of all VRPIs). Streets and roads were the places with the highest frequency of injury (50). The most frequent injured organ was the upper limb (54.17). The most prevalent type of injury was a superficial wound (50). Finally, the most common place of treatment was home (45.83). Conclusions: We determined the incidence rate of self-reported interpersonal VRPI for the first time in Iran based on a national survey. The injuries were more common among young men. We suggest consecutive national surveys with different data gathering methods and more sample sizes. © 2015, Iranian Red Crescent Medical Journal

    Bone mineral density is lower in male than female patients with plaque-type psoriasis in Iran

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    Background There are many similarities with regard to contributing cytokines in patients with psoriasis and osteoporosis. A theory of probable relationship between these two entities has been proposed but there is no concordant consensus. The aim of this study was to evaluate bone mineral density (BMD) in patients with psoriasis. Method and materials This cross-sectional study of BMD was conducted with 64 eligible patients with psoriasis who were referred to the dermatology clinic of Razi hospital in Tehran, Iran in between 2011 and 2012. Results The mean T score of femoral neck was �1.17 and �0.49 in men and women, respectively, which was statistically significant (p =.047). The mean T score of the lumbar spine was �0.93 and �0.30 in men and women, respectively, but not statistically significant (p =.058). In total except with the exclusion of the study site (femur or lumbar), men and women did not have a statistically significant difference with regard to osteoporosis or osteopenia in BMD (p =.114). The Pearson correlation coefficient demonstrated a moderate inverse relationship between age and T score of the femoral neck and lumbar spine (r = �0.419 and �.406, respectively), which was statistically significant (p =.001). Although there was no statistically significant relationship between the Psoriasis Area and Severity Index (PASI) and T scores of the femoral neck (p =.596), a positive and weak correlation was observed between the PASI and T scores for the lumbar spine, which was statistically significant (r = 0.269; p =.03). Conclusion Patients with psoriasis had decreased bone density, which was more significant in men. Prevalence of osteoporosis showed no statistically significant difference when compared with the healthy population in Iran. © 201

    Investigation on the formation of Cu-Fe nano crystalline super-saturated solid solution developed by mechanical alloying

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    In this study, the formation of super saturated solid solution in the binary Cu-Fe system was investigated. Three powder blends with 30, 50 and 70 wt.% of Fe were milled for different times to 96 h. The variations of lattice parameter and inter-planar spacing were calculated and analyzed using X-ray diffraction analysis (XDA). The anisotropy of lattice deformation in the FCC phase was studied and the obtained results were compared to milled pure Cu powder. Furthermore, crystallite size was calculated using Scherer formula in comparison with Rietveld full profile refinement method. Considering the previous studies about the formation of non-equilibrium FCC and BCC phases, the phase evolution has been discussed and the proportion of each phase was calculated using Rietveld refinement method. Supplementary studies on the evolution of microstructure and formation of solid solution were carried out using high resolution transmission electron microscopy (HRTEM). Finally, high angle annular dark field (HAADF) imaging was utilized to find out the level of homogeneity in the resulting phases. While true alloying takes place in each phase, the final structure consists of both FCC and BCC nano-crystallites. © 2012 Elsevier B.V. All rights reserved

    Serum homocysteine level, vitamin B12 levels, and erythrocyte folate in psoriasis: A case-control study

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    Background: One of the most important organ involvements in psoriasis is atherosclerotic cardiovascular disease. Homocysteine is known to have atherogenic properties, but some inconsistency exists in the literature about its probable role as a risk factor of cardiovascular disorder in patients with psoriasis. Objective: Because of some controversies, we compared homocysteine levels and related parameters of metabolic cycles in patients with psoriasis and healthy individuals. Methods: This case-control study was conducted on 50 patients with psoriasis and 50 healthy individuals as the controls. Serum homocysteine, vitamin B12 levels, and erythrocyte folate concentrations were checked in all participants. Results: Mean serum homocysteine, erythrocyte folate, and vitamin B12 levels did not show any significant difference between the two groups (p >.05), but interestingly, in patients with psoriasis, men had a significantly higher incidence of hyperhomocysteinemia and lower levels of erythrocyte folate (p =.14). Overall, there is no significant difference in serum levels of homocysteine and metabolic-related parameters between the case and control group. There was no significant relationship between the severity of psoriasis and the body mass index of patients (p >.05). Conclusion: Patients with psoriasis had a higher body mass index and higher levels of homocysteine in men. Hyperhomocysteinemia could be a predisposing factor of cardiovascular events, but more evaluations as a part of metabolic syndrome in patients with psoriasis are needed. © 201
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