Université de Montréal

About: Université de Montréal is a education organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 45641 authors who have published 100476 publications receiving 4004007 citations. The organization is also known as: University of Montreal & UdeM.

Loss‐of‐function mutations in the Nav1.7 gene underlie congenital indifference to pain in multiple human populations

Abstract: Congenital indifference to pain (CIP) is a rare condition in which patients have severely impaired pain perception, but are otherwise essentially normal. We identified and collected DNA from individuals from nine families of seven different nationalities in which the affected individuals meet the diagnostic criteria for CIP. Using homozygosity mapping and haplotype sharing methods, we narrowed the CIP locus to chromosome 2q24-q31, a region known to contain a cluster of voltage-gated sodium channel genes. From these prioritized candidate sodium channels, we identified 10 mutations in the SCN9A gene encoding the sodium channel protein Na v 1.7. The mutations completely co-segregated with the disease phenotype, and nine of these SCN9A mutations resulted in truncation and loss-of-function of the Na v 1.7 channel. These genetic data further support the evidence that Na v 1.7 plays an essential role in mediating pain in humans, and that SCN9A mutations identified in multiple different populations underlie CIP.

An Integral Equation To Describe the Solvation of Polar Molecules in Liquid Water

Abstract: We developed and implemented a statistical mechanical integral equation theory to describe the hydration structure of complex molecules. The theory, which is an extension of the reference interaction site model (RISM) in three dimensions, yields the average density from the solvent interactions sites at all points r around a molecular solute of arbitrary shape. Both solute−solvent electrostatic and van der Waals interactions are fully included, and solvent packing is taken into account. The approach is illustrated by calculating the average oxygen and hydrogen density of liquid water around two molecular solutes: water and N-methylacetamide. Molecular dynamics simulations are performed to test the results obtained from the integral equation. It is observed that important microscopic structural features of the average water density due to hydrogen bonding are reproduced by the integral equation. The integral equation has a simple formal structure and is easy to implement numerically. It offers a powerful ...

Distinct immunopathologic characteristics of various types of chronic rhinosinusitis in adult Chinese

Abstract: Background Chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP) is reported to be different in inflammatory patterns of the sinonasal mucosa in white patients. Studies in nonwhite populations may further be helpful to understand the pathogenic mechanisms of CRS. Objective To investigate the immunopathologic profiles of CRSwNP and CRSsNP in adult Chinese. Methods Histologic characteristics of surgical samples were analyzed in 50 controls, 94 CRSsNP patients, and 151 CRSwNP patients. Tissue samples from 17 controls, 36 CRSsNP patients, and 45 CRSwNP patients were stained for CD3, CD4, CD8, CD20, CD68, myeloperoxidase, and dendritic cell lysosome-associated membrane protein. Expression profiles of transcription factors of T-cell subsets in relation to cytokines and a marker of natural killer T cell (Vα24) were examined by means of quantitative RT-PCR. Results Over half of CRSwNP patients presented noneosinophilic inflammation. CRSwNP had a higher number of eosinophils, plasma cells, and CD3 + , CD8 + , CD20 + , and CD68 + cells and a lower myeloperoxidase expression rate than CRSsNP. Expression levels of transcription factors and cytokines of T H 1/T H 2/T H 17 were increased, whereas the expression rate of Forkhead box p3 and TGF-β1 was decreased in both CRSsNP and CRSwNP compared with controls. Comparing CRSsNP and CRSwNP, CRSsNP had higher levels of IFN-γ expression, whereas only eosinophilic CRSwNP demonstrated an enhanced expression of GATA-3 and IL-5. Compared with noneosinophilic CRSwNP, an exaggerated T H 2/T H 17 reaction and Vα24 expression were found in eosinophilic CRSwNP. Conclusion Both Chinese CRSsNP and CRSwNP patients demonstrate impaired regulatory T cell function and enhanced T H 1/T H 2/T H 17 responses. CRSsNP is confirmed to be a predominant T H 1 milieu, whereas T H 2 skewed inflammation with predominant T H 17 reactions, and infiltration of natural killer T cells can be demonstrated only in eosinophilic CRSwNP, but not in noneosinophilic CRSwNP.

A review of what is an emerging contaminant

Abstract: A review is presented of how one defines emerging contaminants and what can be included in that group of contaminants which is preferably termed “contaminants of emerging concern”. An historical perspective is given on the evolution of the issues surrounding emerging contaminants and how environmental scientists have tackled this issue. This begins with global lead contamination from the Romans two millennia ago, moves on to arsenic-based and DDT issues and more recently to pharmaceuticals, cyanotoxins, personal care products, nanoparticles, flame retardants, etc. Contaminants of emerging concern will remain a moving target as new chemical compounds are continuously being produced and science continuously improves its understanding of current and past contaminants.

Selecting good expansion terms for pseudo-relevance feedback

Abstract: Pseudo-relevance feedback assumes that most frequent terms in the pseudo-feedback documents are useful for the retrieval. In this study, we re-examine this assumption and show that it does not hold in reality - many expansion terms identified in traditional approaches are indeed unrelated to the query and harmful to the retrieval. We also show that good expansion terms cannot be distinguished from bad ones merely on their distributions in the feedback documents and in the whole collection. We then propose to integrate a term classification process to predict the usefulness of expansion terms. Multiple additional features can be integrated in this process. Our experiments on three TREC collections show that retrieval effectiveness can be much improved when term classification is used. In addition, we also demonstrate that good terms should be identified directly according to their possible impact on the retrieval effectiveness, i.e. using supervised learning, instead of unsupervised learning.