Effects of impurities on radiation damage of silicon solar cells

Impurities effects on radiation damage of silicon solar cell

Thiol density dependent classical potential for methyl-thiol on a Au(111) surface

A new classical potential for methyl-thiol on a Au(111) surface has been developed using density functional theory electronic structure calculations. Energy surfaces between methyl-thiol and a gold surface were investigated in terms of symmetry sites and thiol density. Geometrical optimization was employed over all the configurations while minimum energy and thiol height were determined. Finally, a new interatomic potential has been generated as a function of thiol density, and applications to coarse-grained simulations are presented

Anchored phosphatases modulate glucose homeostasis.

Endocrine release of insulin principally controls glucose homeostasis. Nutrient-induced exocytosis of insulin granules from pancreatic β-cells involves ion channels and mobilization of Ca(2+) and cyclic AMP (cAMP) signalling pathways. Whole-animal physiology, islet studies and live-β-cell imaging approaches reveal that ablation of the kinase/phosphatase anchoring protein AKAP150 impairs insulin secretion in mice. Loss of AKAP150 impacts L-type Ca(2+) currents, and attenuates cytoplasmic accumulation of Ca(2+) and cAMP in β-cells. Yet surprisingly AKAP150 null animals display improved glucose handling and heightened insulin sensitivity in skeletal muscle. More refined analyses of AKAP150 knock-in mice unable to anchor protein kinase A or protein phosphatase 2B uncover an unexpected observation that tethering of phosphatases to a seven-residue sequence of the anchoring protein is the predominant molecular event underlying these metabolic phenotypes. Thus anchored signalling events that facilitate insulin secretion and glucose homeostasis may be set by AKAP150 associated phosphatase activity

Computational and analytical evaluation of the efficiency of using hydrogen as a fuel in an internal combustion engine

There are reasons to look for alternative sources of fuel because of the automobile industry development. Firstly, oil is a mined, not a produced fuel, sooner or later it will run out. According to various statistical sources, known deposits are gradually being depleted. Another important problem is air pollution caused by road transport. Most of the existing cars run on gasoline and diesel engines that burn oil to get the car going. Combustion of hydrocarbons that make up oil releases a large amount of harmful substances, in particular, particulate matter and volatile organic compounds. Using hydrogen as an alternative fuel can solve the problem of finding new oil fields, and also, due to the absence of emissions into the atmosphere, it can solve the problem of air pollution. The article presents a brief history of the development of engine building and a description of hydrogen technologies in engines. The article presents a computational and analytical assessment of the efficiency of using hydrogen fuel in an internal combustion engine in relation to the bus fleet of the Yekaterinburg city. It was found that the conversion of a gasoline engine to hydrogen fuel leads to a decrease in specific fuel consumption by 20% (at the nominal mode). It is shown that the payback period for the transfer of 20 buses to hydrogen is about 8 years. © Published under licence by IOP Publishing Ltd

Psychological principles of successful aging technologies: A mini-review

Based on resource-oriented conceptions of successful life-span development, we propose three principles for evaluating assistive technology: (a) net resource release; (b) person specificity, and (c) proximal versus distal frames of evaluation. We discuss how these general principles can aid the design and evaluation of assistive technology in adulthood and old age, and propose two technological strategies, one targeting sensorimotor and the other cognitive functioning. The sensorimotor strategy aims at releasing cognitive resources such as attention and working memory by reducing the cognitive demands of sensory or sensorimotor aspects of performance. The cognitive strategy attempts to provide adaptive and individualized cuing structures orienting the individual in time and space by providing prompts that connect properties of the environment to the individual's action goals. We argue that intelligent assistive technology continuously adjusts the balance between `environmental support' and `self-initiated processing' in person-specific and aging-sensitive ways, leading to enhanced allocation of cognitive resources. Furthermore, intelligent assistive technology may foster the generation of formerly latent cognitive resources by activating developmental reserves (plasticity). We conclude that `lifespan technology', if co-constructed by behavioral scientists, engineers, and aging individuals, offers great promise for improving both the transition from middle adulthood to old age and the degree of autonomy in old age in present and future generations. Copyright (C) 2008 S. Karger AG, Basel

A benchmark for epithelial cell tracking

Segmentation and tracking of epithelial cells in light microscopy (LM) movies of developing tissue is an abundant task in cell- and developmental biology. Epithelial cells are densely packed cells that form a honeycomb-like grid. This dense packing distinguishes membrane-stained epithelial cells from the types of objects recent cell tracking benchmarks have focused on, like cell nuclei and freely moving individual cells. While semi-automated tools for segmentation and tracking of epithelial cells are available to biologists, common tools rely on classical watershed based segmentation and engineered tracking heuristics, and entail a tedious phase of manual curation. However, a different kind of densely packed cell imagery has become a focus of recent computer vision research, namely electron microscopy (EM) images of neurons. In this work we explore the benefits of two recent neuron EM segmentation methods for epithelial cell tracking in light microscopy. In particular we adapt two different deep learning approaches for neuron segmentation, namely Flood Filling Networks and MALA, to epithelial cell tracking. We benchmark these on a dataset of eight movies with up to 200 frames. We compare to Moral Lineage Tracing, a combinatorial optimization approach that recently claimed state of the art results for epithelial cell tracking. Furthermore, we compare to Tissue Analyzer, an off-the-shelf tool used by Biologists that serves as our baseline

Effect of impurities on transport through organic molecular films from first principles

We calculate electron transport through molecular monolayers of saturated alkanes with point defects from first principles. Single defects (incorporated Au ions, kinks, dangling bonds) produce deep localized levels in the gap between occupied and unoccupied molecular levels. Single defects produce steps on the I-V curve, whereas pairs of (unlike and like) defects give negative differential resistance peaks. The results are discussed in relation to the observed unusual transport behavior of organic monolayers and compared with transport through conjugated polythiophenes.Comment: 5 pages, 2 figures. Small typos corrected and text slightly shortened. To appear in Phys. Rev.

Conductance statistics from a large array of sub-10 nm molecular junctions

Devices made of few molecules constitute the miniaturization limit that both inorganic and organic-based electronics aspire to reach. However, integration of millions of molecular junctions with less than 100 molecules each has been a long technological challenge requiring well controlled nanometric electrodes. Here we report molecular junctions fabricated on a large array of sub-10 nm single crystal Au nanodots electrodes, a new approach that allows us to measure the conductance of up to a million of junctions in a single conducting Atomic Force Microscope (C-AFM) image. We observe two peaks of conductance for alkylthiol molecules. Tunneling decay constant (beta) for alkanethiols, is in the same range as previous studies. Energy position of molecular orbitals, obtained by transient voltage spectroscopy, varies from peak to peak, in correlation with conductance values.Comment: ACS Nano (in press

'My story is like a magic wand': a qualitative study of personal storytelling and activism to stop violence against women in Turkey.

Background: Telling personal stories of violence has been central to recent advocacy efforts to prevent violence against women around the world. In this paper, we explore the use of personal storytelling as a form of activism to prevent femicide in Turkey. This study is part of a broader storytelling initiative called SHAER (Storytelling for Health: Acknowledgement, Expression and Recovery) to alleviate the psychological and emotional suffering of women who have experienced gender-based violence in high-prevalence settings.Objectives: We conceptually explore personal stories of violence as a form of both distributed agency and activism. This conceptual framework is used to answer the following research question in the Turkish context: How do women use their personal stories of interpersonal violence for their own benefit (support) and that of others (activism)?Methods: Our study is based on 20 in-depth semi-structured interviews with women who have experienced violence and were purposefully recruited by the 'We Will End Femicide' Platform in Istanbul. Interviews were conducted between March and August 2019. We used inductive and deductive thematic analysis to identify instances of personal storytelling at three levels: intrapersonal, relational and collective.Results: Our results show how the use of personal storytelling can provide a means of healing from experiences of violence. However, this process is not linear and is often influenced by the surrounding context including: the listener of the story, their reaction, and what social networks the woman has to support her. In supportive social contexts, personal storytelling can be an effective support for activism against violence: personal stories can provide opportunities for individuals to shape broader discourses about violence against women and the right of women to share their stories.Conclusions: Telling one's personal story of violence can both support women's agency and contribute to the collective struggle against violence against women more broadly