8,211 research outputs found

    Functional polymeric coatings for csi(Tl) scintillators

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    The handling of inorganic scintillators (e.g., alkali metal halides) can benefit from the availability of polymeric materials able to adhere to their surface. Polymeric materials, such as epoxy resins, can act as protective coatings, as adhesives for photodiodes to be connected with the scintillator surface, and as a matrix for functional fillers to improve the optical properties of scintillators. Here, the optical properties of two epoxy resins (E-30 by Prochima, and Technovit Epox by Heraeus Kulzer) deposited on the surface of a scintillator crystal made of CsI(Tl) were investigated, in order to improve the detection of high-energy radiation. It is found that these resins are capable of adhering to the surface of alkali metal halides. Adhesion, active at the epoxy–CsI(Tl) interface, can be explained on the basis of Coulomb forces acting between the ionic solid surface and an ionic intermediate of synthesis generated during the epoxy setting reaction. Technovit Epox showed higher transparency, and it was also functionalized by embedding white powdered pigments (PTFE or BaSO4) to achieve an optically reflective coating on the scintillator surface

    High-Definition Optical Coherence Tomography for the in vivo Detection of Demodex Mites

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    Background: Demodex mites are involved in different skin diseases and are commonly detected by skin scrape tests or superficial biopsies. A new high-definition optical coherence tomography (HD-OCT) with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode might offer the possibility of noninvasive and fast in vivo examination of demodex mites. Methods: Twenty patients with demodex-related skin diseases and 20 age- and gender-matched healthy controls were examined by HD-OCT. Mites per follicle and follicles per field of view were counted and compared to skin scrape tests. Results: HD-OCT images depicted mites in the en-face mode as bright round dots in groups of 3-5 mites per hair follicle. In the patients with demodex-related disease, a mean number of 3.4 mites per follicle were detected with a mean number of 2.9 infested follicles per area of view compared to a mean of 0.6 mites in 0.4 infested follicles in the controls. The skin scrape tests were negative in 21% of the patients. Conclusion: The innovative HD-OCT enables fast and noninvasive in vivo recognition of demodex mites and might become a useful tool in the diagnosis and treatment monitoring of demodex-related skin diseases. Copyright (C) 2012 S. Karger AG, Base

    Influence of the thermomechanical characteristics of low-density polyethylene substrates on the thermoresistive properties of graphite nanoplatelet coatings

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    Morphological, structural, and thermoresistive properties of films deposited on low-density polyethylene (LDPE) substrates are investigated for possible application in flexible electronics. Scanning and transmission electron microscopy analyses, and X-ray diffraction measurements show that the films consist of overlapped graphite nanoplatelets (GNP) each composed on average of 41 graphene layers. Differential scanning calorimetry and dynamic-mechanical-thermal analysis indicate that irreversible phase transitions and large variations of mechanical parameters in the polymer substrates can be avoided by limiting the temperature variations between −40 and 40◦ C. Electrical measurements performed in such temperature range reveal that the resistance of GNP films on LDPE substrates increases as a function of the temperature, unlike the behavior of graphite-based materials in which the temperature coefficient of resistance is negative. The explanation is given by the strong influence of the thermal expansion properties of the LDPE substrates on the thermo-resistive features of GNP coating films. The results show that, narrowing the temperature range from 20 to 40◦ C, the GNP on LDPE samples can work as temperature sensors having linear temperature-resistance relationship, while keeping constant the temperature and applying mechanical strains in the 0–4.2 × 10−3 range, they can operate as strain gauges with a gauge factor of about 48

    Simultaneous detection of enteropathogenic viruses in buffalos faeces using multiplex reverse transcription-polymerase chain reaction (mRT-PCR)

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    A multiplex reverse transcription- polymerase chain reaction (mRT-PCR) assay that detects Bovine Viral Diarrhoea Virus, Bovine Coronavirus, and Group A Rotaviruses in infected cell-culture fluids and clinical faecal samples is described. One hundred twenty faecal samples from buffalo calves with acute gastroenteritis were tested. The mRT-PCR was validated against simplex RT-PCR with published primers for Pestivirus, Coronavirus and Rotavirus. The multiplex RT-PCR was equally sensitive and specific in detecting viral infections compared with simplex RT-PCR. The mRT-PCR readily identified viruses by discriminating the size of their amplified gene products. This mRT-PCR may be a sensitive and rapid assay for surveillance of buffalo enteric viruses in field specimens. This novel multiplex RT-PCR is an attractive technique for the rapid, specific, and cost-effective laboratory diagnosis of acute gastroenteritis

    Conversación en París con André Vauchez

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    The Quest for Understanding in Relativistic Quantum Physics

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    We discuss the status and some perspectives of relativistic quantum physics.Comment: Invited contribution to the Special Issue 2000 of the Journal of Mathematical Physics, 38 pages, typos corrected and references added, as to appear in JM

    Classificação de touros Nelore em função de diferentes índices bioeconômicos de seleção.

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    O objetivo deste trabalho foi comparar a classificação de touros da raça Nelore em função de três índices bioeconômicos de seleção, além do índice de qualificação genética (IQG). Foi utilizado o banco histórico de avaliações genéticas concedido pela Embrapa Pantanal (2020), contendo 865 touros nascidos entre 1955 e 2014. Os três índices bioeconômicos de seleção utilizados consideraram características de produção, reprodução e de qualidade de carcaça. As ponderações para os critérios de seleção foram estimadas considerando o mesmo objetivo de seleção, porém para diferentes medidas de avaliação econômica utilizadas na pecuária, resultando em valores econômicos expressos com base nas avaliações: por animal (VACA), por Arroba (@) e por Unidade Animal (UA) (Portes et al., 2021). As correlações de Spearman foram altas entre os índices VACA e UA (1,0), IQG e @ (0,86), sugerindo ordenamento semelhante dos touros, e moderadas entre IQG e VACA (0,64) e UA (0,64) e entre @ e VACA (0,57) e UA (0,57), indicando reordenação dos touros. Apenas o índice arroba (@) resultará em ordem semelhante de classificação dos touros ao IQG que é o índice usualmente utilizado pelo programa de melhoramento de gado de corte - Embrapa Geneplus

    Involvement of Mhc Loci in immune responses that are not Ir-gene-controlled

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    Twenty-nine randomly chosen, soluble antigens, many of them highly complex, were used to immunize mice of two strains, C3H and B10.RIII. Lymphnode cells from the immunized mice were restimulated in vitro with the priming antigens and the proliferative response of the cells was determined. Both strains were responders to 28 of 29 antigens. Eight antigens were then used to immunize 11 congenic strains carrying different H-2 haplotypes, and the T-cell proliferative responses of these strains were determined. Again, all the strains responded to seven of the eight antigens. These experiments were then repeated, but this time -antibodies specific for the A (AA) or E (EE) molecules were added to the culture to block the in vitro responsiveness. In all but one of the responses, inhibition with both A-specific and E-specific antibodies was observed. The response to one antigen (Blastoinyces) was exceptional in that some strains were nonresponders to this antigen. Furthermore, the response in the responder strains was blocked with A-specific, but not with E-specific, antibodies. The study demonstrates that responses to antigens not controlled by Irr genes nevertheless require participation of class II Mhc molecules. In contrast to Ir gene-controlled responses involving either the A- or the E-molecule controlling loci (but never both), the responses not Ir-controlled involve participation of both A- and E-controlling loci. The lack of Ir-gene control is probably the result of complexity of the responses to multiple determinants. There is thus no principal difference between responses controlled and those not controlled by Ir genes: both types involve the recognition of the antigen, in the context of Mhc molecules

    The effects of instrumental action on perceptual hand maps

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    Perceiving the external spatial location of body parts using position sense requires that immediate proprioceptive afferent signals be integrated with information about body size and shape. Longo and Haggard (Proc Natl Acad Sci USA 107:11727–11732, 2010) developed a method to measure perceptual hand maps reflecting this metric information about body size and shape. In this paradigm, participants indicate the perceived location of landmarks on their occluded hand by pointing with a long baton held in their other hand. By comparing the relative location of judgments of different hand landmarks, perceptual hand maps can be constructed and compared to actual hand structure. The maps show large and highly stereotyped distortions. Here, I investigated the potential effect of biases related to active motor control of the hand doing the pointing in these distortions. Participants localized the fingertip and knuckle of each finger on their occluded left hand either by actively pointing with a baton held in their right hand (pointing condition) or by giving verbal commands to an experimenter on how to move the baton (verbal condition). Similar distortions were clearly apparent in both conditions, suggesting that they are not an artifact of motor control biases related to the pointing hand
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