Exciton Spin Dynamics in Semiconductor Quantum Wells

In this paper we will review Exciton Spin Dynamics in Semiconductor Quantum Wells. The spin properties of excitons in nanostructures are determined by their fine structure. We will mainly focus in this review on GaAs and InGaAs quantum wells which are model systems.Comment: 55 pages, 27 figure

Assessing the O2 budget under sea ice: An experimental and modelling approach

The objective of this study was to assess the O2 budget in the water under sea ice combining observations and modelling. Modelling was used to discriminate between physical processes, gas-specific transport (i.e., ice-atmosphere gas fluxes and gas bubble buoyancy) and bacterial respiration (BR) and to constrain bacterial growth efficiency (BGE). A module describing the changes of the under-ice water properties, due to brine rejection and temperature-dependent BR, was implemented in the one-dimensional halo-thermodynamic sea ice model LIM1D. Our results show that BR was the dominant biogeochemical driver of O2 concentration in the water under ice (in a system without primary producers), followed by gas specific transport. The model suggests that the actual contribution of BR and gas specific transport to the change in seawater O2 concentration was 37% during ice growth and 48% during melt. BGE in the water under sea ice, as retrieved from the simulated O2 budget, was found to be between 0.4 and 0.5, which is in line with published BGE values for cold marine waters. Given the importance of BR to seawater O2 in the present study, it can be assumed that bacteria contribute substantially to organic matter consumption and gas fluxes in ice-covered polar oceans. In addition, we propose a parameterization of polar marine bacterial respiration, based on the strong temperature dependence of bacterial respiration and the high growth efficiency observed here, for further biogeochemical ocean modelling applications, such as regional or large-scale Earth System model

Contribution of fluorescence spectroscopy and independent components analysis to the evaluation of NaCl and KCl effects on molecular-structure and fat melting temperatures of Cantal-type cheese

International audienceOne of the main objectives of the present study was to investigate by different analytical techniques (physicochemical analysis, dynamic rheology, and synchronous fluorescence spectroscopy) the impact of the NaCl reduction and its substitution by KCl on the molecular structure and fat melting of Cantal-type cheese. Molecular structure changes were investigated on five cheese sample formulations from 20 to 60 degrees C with five offsets using SF spectroscopy coupled with independent components analysis. Results showed that significant differences were observed for protein, Cl, Ca, Na and K contents of cheeses. Complex viscosity decreased as the temperature increased for the different cheeses. SF spectroscopy provided relevant information related to protein and fat structures with varying salt concentrations and type during melting, allowing investigation of molecular structure changes of the cheeses. In addition, similar fat melting temperatures for each cheese were obtained regardless the technique used (dynamic rheology and fluorescence). (C) 2017 Elsevier Ltd. All rights reserved

Providing interactive access to architectural floorplans for blind people

The TeDUB system is a new method for providing access to graphic information for blind people, using synthetic speech, sounds and forcefeedback information from a joystick. Currently certain types of visual diagram, such as architectural floorplans, can be automated by the TeDUB system and presented to the user. A variety of features to allow users to navigate through the diagram (Text View, Map View, Spatial Navigation View, Walkthrough) and explore the information have been developed. This article presents an overview of the TeDUB system, some of the work carried out in developing the user requirements for the system, and an evaluation with 34 blind participants of the floorplan prototype of the systemPeer reviewe

Biofilm formation and antimicrobial resistance genes of coagulase-negative staphylococci isolated from cows with mastitis in Argentina

Mastitis affects the health and welfare of dairy cows worldwide. Coagulase-negative staphylococci (CNS) are known to form biofilms and are increasingly recognized as a cause of persistent bovine intramammary infections. A total of 90 CNS isolated from cows with clinical and subclinical mastitis in Argentina from 2008 to 2014 were identified by PCR-RFLP using the gap gene. Standard microtiter plate assays were used to assess CNS biofilm formation, and Staphylococcus haemolyticus species formed the strongest biofilms. The presence of biofilm-associated genes icaA, bap and aap was detected in a few isolates, while embP, fbe, atlE and eno were present in the majority of isolates. Genes encoding resistance to β-lactams were detected among the isolates; blaZ, mecA and mecC were detected in 21, 4 and 1 isolate, respectively. Resistance to macrolides and lincosamides (n = 6) was attributable to ermB, ermC, mphC or mrsA or a combination of those genes. In this study, we identified CNS species involved in mastitis and provide information about pathogenicity and antimicrobial resistance, which is essential to design efficient strategies to control mastitis caused by CNS.Fil: Srednik, Mariela Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Microbiología Veterinaria; ArgentinaFil: Tremblay, Yannick D.N.. University of Montreal; CanadáFil: Labrie, Josée. University of Montreal; CanadáFil: Archambault, Marie. University of Montreal; Canadá. Regroupement de Recherche Pour un lait de Qualite Optimale; CanadáFil: Jacques, Mario. University of Montreal; Canadá. Regroupement de Recherche Pour un lait de Qualite Optimale; Canadá. Canadian Bovine Mastitis and Milk Quality Research Network; CanadáFil: Fernandez Cirelli, Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: Gentilini, Elida Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Microbiología Veterinaria; Argentin

An integrated pipeline for comprehensive analysis of immune cells in human brain tumor clinical samples.

Human tissue samples represent an invaluable source of information for the analysis of disease-specific cellular alterations and their variation between different pathologies. In cancer research, advancing a comprehensive understanding of the unique characteristics of individual tumor types and their microenvironment is of considerable importance for clinical translation. However, investigating human brain tumor tissue is challenging due to the often-limited availability of surgical specimens. Here we describe a multimodule integrated pipeline for the processing of freshly resected human brain tumor tissue and matched blood that enables analysis of the tumor microenvironment, with a particular focus on the tumor immune microenvironment (TIME). The protocol maximizes the information yield from limited tissue and includes both the preservation of bulk tissue, which can be performed within 1 h following surgical resection, as well as tissue dissociation for an in-depth characterization of individual TIME cell populations, which typically takes several hours depending on tissue quantity and further downstream processing. We also describe integrated modules for immunofluorescent staining of sectioned tissue, bulk tissue genomic analysis and fluorescence- or magnetic-activated cell sorting of digested tissue for subsequent culture or transcriptomic analysis by RNA sequencing. Applying this pipeline, we have previously described the overall TIME landscape across different human brain malignancies, and were able to delineate disease-specific alterations of tissue-resident versus recruited macrophage populations. This protocol will enable researchers to use this pipeline to address further research questions regarding the tumor microenvironment