1,424 research outputs found

    Study of Zn O,S Films grown by Aerosol Assisted Chemical Vapour Deposition and their Application as Buffer Layers in Cu In,Ga S,Se 2 Solar Cells

    Get PDF
    To reduce the use of toxic and expensive elements in chalcopyrite thin film solar cells, materials such as cadmium or indium used in buffer layers need to be substituted. Zn O,S is considered to be a potential buffer layer material when deposited with a fast and inexpensive method. Zn O,S layers have been prepared by aerosol assisted chemical vapour deposition AACVD technique. AACVD technique is a simple non vacuum process where the thin film deposition temperatures do not exceed 250 C. 10 mM spray solution was made by dissolving zinc II acetylacetonate monohydrate in ethanol. The films were grown on Mo substrate at 225 C film growth temperature . The effect of deposition parameters spray solution concentration, N2 flow rate, H2S flow rate on Zn O,S thin film properties were studied with SEM and XRD. Thereupon optimizing the deposition parameters, homogeneous and compact Zn O,S thin films were obtained and the films were employed in the chalcopyrite thin film solar cell structure by growing films on Cu In,Ga S,Se 2 substrates industrially produced by BOSCH Solar CISTech GmbH. The resulting cells were studied using current voltage and quantum efficiency analysis and compared with solar cell references that include In2S3 and CdS as buffer layer deposited by ion layer gas reaction and chemical bath deposition, respectively. The best output of the solar cell containing Zn O,S as buffer layer and without intrinsic ZnO under standard test conditions AM 1.5G, 100 mW cm2, 25 C is Voc 573 mV, Jsc 39.2 mA cm2, FF 68.4 and efficiency of 15.4 being slightly better than the In2S3 or CdS containing solar cell reference

    Emotional persistence in online chatting communities

    Get PDF
    How do users behave in online chatrooms, where they instantaneously read and write posts? We analyzed about 2.5 million posts covering various topics in Internet relay channels, and found that user activity patterns follow known power-law and stretched exponential distributions, indicating that online chat activity is not different from other forms of communication. Analysing the emotional expressions (positive, negative, neutral) of users, we revealed a remarkable persistence both for individual users and channels. I.e. despite their anonymity, users tend to follow social norms in repeated interactions in online chats, which results in a specific emotional "tone" of the channels. We provide an agent-based model of emotional interaction, which recovers qualitatively both the activity patterns in chatrooms and the emotional persistence of users and channels. While our assumptions about agent's emotional expressions are rooted in psychology, the model allows to test different hypothesis regarding their emotional impact in online communication.Comment: 34 pages, 4 main and 12 supplementary figure

    Combined In Silico, In Vivo, and In Vitro Studies Shed Insights into the Acute Inflammatory Response in Middle-Aged Mice

    Get PDF
    We combined in silico, in vivo, and in vitro studies to gain insights into age-dependent changes in acute inflammation in response to bacterial endotoxin (LPS). Time-course cytokine, chemokine, and NO2-/NO3- data from "middle-aged" (6-8 months old) C57BL/6 mice were used to re-parameterize a mechanistic mathematical model of acute inflammation originally calibrated for "young" (2-3 months old) mice. These studies suggested that macrophages from middle-aged mice are more susceptible to cell death, as well as producing higher levels of pro-inflammatory cytokines, vs. macrophages from young mice. In support of the in silico-derived hypotheses, resident peritoneal cells from endotoxemic middle-aged mice exhibited reduced viability and produced elevated levels of TNF-α, IL-6, IL-10, and KC/CXCL1 as compared to cells from young mice. Our studies demonstrate the utility of a combined in silico, in vivo, and in vitro approach to the study of acute inflammation in shock states, and suggest hypotheses with regard to the changes in the cytokine milieu that accompany aging. © 2013 Namas et al

    An Intelligent Decision Support System for the Detection of Meat Spoilage using Multispectral Images

    Get PDF
    In food industry, quality and safety are considered important issues worldwide that are directly related to health and social progress. The use of vision technology for quality testing of food production has the obvious advantage of being able to continuously monitor a production using non-destructive methods, thus increasing the quality and minimizing cost. The performance of an intelligent decision support system has been evaluated in monitoring the spoilage of minced beef stored either aerobically or under modified atmosphere packaging, at different storage temperatures (0, 5, 10, and 15 °C) utilising multispectral imaging information. This paper utilises a neuro-fuzzy model which incorporates a clustering pre-processing stage for the definition of fuzzy rules, while its final fuzzy rule base is determined by competitive learning. Initially, meat samples are classified according to their storage conditions, while identification models are then utilised for the prediction of the Total Viable Counts of bacteria. The innovation of the proposed approach is further extended to the identification of the temperature used for storage, utilizing only imaging spectral information. Results indicated that spectral information in combination with the proposed modelling scheme could be considered as an alternative methodology for the accurate evaluation of meat spoilage

    FCGR polymorphisms in the treatment of rheumatoid arthritis with Fc-containing TNF inhibitors

    Get PDF
    [EN] Objectives: Reproducible association of a functional polymorphism in FCGR2A with response to a TNF inhibitor (TNFi) in patients with rheumatoid arthritis (RA) led us to explore other Fc?R functional polymorphisms. Methods: Functional polymorphisms FCGR3A F158V, FCGR2B I223T and promoter VNTR in FCGRT were analyzed in up to 429 patients with RA. Response to TNFi was recorded during standard care at 3, 6 and 12 months of follow-up. Fixed effects meta-analysis of studies addressing FCGR3A F158V polymorphism, which is the most studied of these polymorphisms, was conducted with inverse variance weighting. Results: None of the functional polymorphisms were associated with change in DAS28. Meta-analysis of the seven studies (899 patients) with available data addressing association of FCGR3A F158V with response to TNFi in RA showed no association (OR: 1.11, 95% CI: 0.8-1.5; p = 0.5). Conclusion: None of the three functional polymorphisms in Fc?R genes showed association with response to TNFi in patients with RA. These negative results were obtained in spite of the larger size of this study relative to previous studies addressing the same polymorphisms. In addition, meta-analysis of FCGR3A F158V was also negative against the results provided by previous studies

    Increasing Dominance - the Role of Advertising, Pricing and Product Design

    Get PDF
    Despite the empirical relevance of advertising strategies in concentrated markets, the economics literature is largely silent on the effect of persuasive advertising strategies on pricing, market structure and increasing (or decreasing) dominance. In a simple model of persuasive advertising and pricing with differentiated goods, we analyze the interdependencies between ex-ante asymmetries in consumer appeal, advertising and prices. Products with larger initial appeal to consumers will be advertised more heavily but priced at a higher level - that is, advertising and price discounts are strategic substitutes for products with asymmetric initial appeal. We find that the escalating effect of advertising dominates the moderating effect of pricing so that post-competition market shares are more asymmetric than pre-competition differences in consumer appeal. We further find that collusive advertising (but competitive pricing) generates the same market outcomes, and that network effects lead to even more extreme market outcomes, both directly and via the effect on advertising

    The MDM2-p53 pathway is involved in preconditioning-induced neuronal tolerance to ischemia.

    Get PDF
    Brain preconditioning (PC) refers to a state of transient tolerance against a lethal insult that can be evoked by a prior mild event. It is thought that PC may induce different pathways responsible for neuroprotection, which may involve the attenuation of cell damage pathways, including the apoptotic cell death. In this context, p53 is a stress sensor that accumulates during brain ischemia leading to neuronal death. The murine double minute 2 gene (MDM2), a p53-specific E3 ubiquitin ligase, is the main cellular antagonist of p53, mediating its degradation by the proteasome. Here, we study the role of MDM2-p53 pathway on PC-induced neuroprotection both in cultured neurons (in vitro) and rat brain (in vivo). Our results show that PC increased neuronal MDM2 protein levels, which prevented ischemiainduced p53 stabilization and neuronal death. Indeed, PC attenuated ischemia-induced activation of the p53/PUMA/caspase-3 signaling pathway. Pharmacological inhibition of MDM2-p53 interaction in neurons abrogated PC-induced neuroprotection against ischemia. Finally, the relevance of the MDM2-p53 pathway was confirmed in rat brain using a PC model in vivo. These findings demonstrate the key role of the MDM2-p53 pathway in PC-induced neuroprotection against a subsequent ischemic insult and poses MDM2 as an essential target in ischemic tolerance

    Planck intermediate results. XLI. A map of lensing-induced B-modes

    Get PDF
    The secondary cosmic microwave background (CMB) BB-modes stem from the post-decoupling distortion of the polarization EE-modes due to the gravitational lensing effect of large-scale structures. These lensing-induced BB-modes constitute both a valuable probe of the dark matter distribution and an important contaminant for the extraction of the primary CMB BB-modes from inflation. Planck provides accurate nearly all-sky measurements of both the polarization EE-modes and the integrated mass distribution via the reconstruction of the CMB lensing potential. By combining these two data products, we have produced an all-sky template map of the lensing-induced BB-modes using a real-space algorithm that minimizes the impact of sky masks. The cross-correlation of this template with an observed (primordial and secondary) BB-mode map can be used to measure the lensing BB-mode power spectrum at multipoles up to 20002000. In particular, when cross-correlating with the BB-mode contribution directly derived from the Planck polarization maps, we obtain lensing-induced BB-mode power spectrum measurement at a significance level of 12σ12\,\sigma, which agrees with the theoretical expectation derived from the Planck best-fit Λ\LambdaCDM model. This unique nearly all-sky secondary BB-mode template, which includes the lensing-induced information from intermediate to small (10100010\lesssim \ell\lesssim 1000) angular scales, is delivered as part of the Planck 2015 public data release. It will be particularly useful for experiments searching for primordial BB-modes, such as BICEP2/Keck Array or LiteBIRD, since it will enable an estimate to be made of the lensing-induced contribution to the measured total CMB BB-modes.Comment: 20 pages, 12 figures; Accepted for publication in A&A; The B-mode map is part of the PR2-2015 Cosmology Products; available as Lensing Products in the Planck Legacy Archive http://pla.esac.esa.int/pla/#cosmology; and described in the 'Explanatory Supplement' https://wiki.cosmos.esa.int/planckpla2015/index.php/Specially_processed_maps#2015_Lensing-induced_B-mode_ma

    Perceptions of Pakistani medical students about drugs and alcohol: a questionnaire-based survey

    Get PDF
    BACKGROUND: Drug abuse is hazardous and known to be prevalent among young adults, warranting efforts to increase awareness about harmful effects and to change attitudes. This study was conducted to assess the perceptions of a group of medical students from Pakistan, a predominantly Muslim country, regarding four drugs namely heroin, charas, benzodiazepines and alcohol. RESULTS: In total, 174 self-reported questionnaires were received (87% response rate). The most commonly cited reasons for why some students take these drugs were peer pressure (96%), academic stress (90%) and curiosity (88%). The most commonly cited justifiable reason was to go to sleep (34%). According to 77%, living in the college male hostel predisposed one to using these drugs. Sixty percent of students said that the drugs did not improve exam performance, while 54% said they alleviated stress. Seventy-eight percent said they did not intend to ever take drugs in the future. Females and day-scholars were more willing to discourage a friend who took drugs. Morality (78%), religion (76%) and harmful effects of drugs (57%) were the most common deterrents against drug intake. Five suggestions to decrease drug abuse included better counseling facilities (78%) and more recreational facilities (60%). CONCLUSION: Efforts need to be made to increase student awareness regarding effects and side effects of drugs. Our findings suggest that educating students about the adverse effects as well as the moral and religious implications of drug abuse is more likely to have a positive impact than increased policing. Proper student-counseling facilities and healthier avenues for recreation are also required
    corecore