1,061 research outputs found

    Introduction

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    Comparison of the Interactions of Transferrin Receptor and Transferrin Receptor 2 with Transferrin and the Hereditary Hemochromatosis Protein HFE

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    The transferrin receptor (TfR) interacts with two proteins important for iron metabolism, transferrin (Tf) and HFE, the protein mutated in hereditary hemochromatosis. A second receptor for Tf, TfR2, was recently identified and found to be functional for iron uptake in transfected cells (Kawabata, H., Germain, R. S., Vuong, P. T., Nakamaki, T., Said, J. W., and Koeffler, H. P. (2000) J. Biol. Chem. 275, 16618-16625). TfR2 has a pattern of expression and regulation that is distinct from TfR, and mutations in TfR2 have been recognized as the cause of a non-HFE linked form of hemochromatosis (Camaschella, C., Roetto, A., Cali, A., De Gobbi, M., Garozzo, G., Carella, M., Majorano, N., Totaro, A., and Gasparini, P. (2000) Nat. Genet. 25, 14-15). To investigate the relationship between TfR, TfR2, Tf, and HFE, we performed a series of binding experiments using soluble forms of these proteins. We find no detectable binding between TfR2 and HFE by co-immunoprecipitation or using a surface plasmon resonance-based assay. The affinity of TfR2 for iron-loaded Tf was determined to be 27 nM, 25-fold lower than the affinity of TfR for Tf. These results imply that HFE regulates Tf-mediated iron uptake only from the classical TfR and that TfR2 does not compete for HFE binding in cells expressing both forms of TfR

    Visual similarity in masking and priming: The critical role of task relevance

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    Cognitive scientists use rapid image sequences to study both the emergence of conscious perception (visual masking) and the unconscious processes involved in response preparation (masked priming). The present study asked two questions: (1) Does image similarity influence masking and priming in the same way? (2) Are similarity effects in both tasks governed by the extent of feature overlap in the images or only by task-relevant features? Participants in Experiment 1 classified human faces using a single dimension even though the faces varied in three dimensions (emotion, race, sex). Abstract geometric shapes and colors were tested in the same way in Experiment 2. Results showed that similarity reduced the visibility of the target in the masking task and increased response speed in the priming task, pointing to a double-dissociation between the two tasks. Results also showed that only task-relevant (not objective) similarity influenced masking and priming, implying that both tasks are influenced from the beginning by intentions of the participant. These findings are interpreted within the framework of a reentrant theory of visual perception. They imply that intentions can influence object formation prior to the separation of vision for perception and vision for action

    Theory of terahertz electric oscillations by supercooled superconductors

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    We predict that below T_c a regime of negative differential conductivity (NDC) can be reached. The superconductor should be supercooled to T<T_c in the normal phase under DC voltage. In such a nonequilibrium situation the NDC of the superconductor is created by the excess conductivity of the fluctuation Cooper pairs. We propose NDC of supercooled superconductors to be used as an active medium for generation of electric oscillations. Such generators can be used in the superconducting electronics as a new type THz source of radiation. Oscillations can be modulated by the change of the bias voltage, electrostatic doping by a gate electrode when the superconductor is the channel of a field effect transistor, or by light. When small amplitude oscillations are stabilized near the critical temperature T_c the generator can be used as a bolometer. The essential for the applications NDC is predicted by the solution of the Boltzmann kinetic equation for the metastable in the normal phase Cooper pairs. Boltzmann equation for fluctuation Cooper pairs is a result of state-of-the-art application of the microscopic theory of superconductivity. Our theoretical conclusions are based on some approximations like time dependent Ginzburg-Landau theory, but nevertheless can reliably predict appearance of NDC. The maximal frequency at which superconductors can operate as generators is determined by the critical temperature \hbar omega_max ~ k_B T_c. For high-T_c superconductors this maximal frequency falls well inside the terahertz range. Technical conditions to avoid nucleation of the superconducting phase are briefly discussed. We suggest that nanostructured high-T_c superconductors patterned in a single chip can give the best technical performance of the proposed oscillator.Comment: 7 page

    REVIEW: Life-cycle, total-industry genetic improvement of feed efficiency in beef cattle: Blueprint for the Beef Improvement Federation

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    On a life-cycle basis, beef animals are able to consume large amounts of low-cost, low-quality forages relative to higher-cost concentrates compared with pigs and chickens. However, of the 3, beef is still more expensive to produce on a cost–per–edible pound basis. Accordingly, there is need for genetic programs and management changes that will improve efficiency, sustainability, and profitability of beef production. Options include improving reproductive rate, reducing feed used for maintenance, or both, while not reducing output. A goal for improving efficiency of feed utilization is to reduce the amount or proportion of feed used for maintenance. Such reduction is a target for genetic improvement, but such a goal does not include defining a single measure of efficiency. A single efficiency measure would likely lead to single-trait selection and not account for any potentially antagonistic effects on other production characteristics. Because we are not able to explain all variation in individual-animal intake from only knowledge of BW maintained and level of production, measuring feed intake is necessary. Therefore, our recommendation is that national cattle evaluation systems analyze feed intake as an economically relevant trait with incorporation of appropriate indicator traits for an EPD for feed intake requirements that could then be used in a multiple-trait setting such as in a selection index. With improvements in technology for measurement of feed intake, individual measures of feed intake should continually be collected to facilitate development of genetic predictors that enhance accuracy of prediction of progeny differences in national cattle evaluations

    Risk Factors for Moral Injury Among Canadian Armed Forces Personnel

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    Objectives: The traumatic nature of high-risk military deployment events, such as combat, is well-recognized. However, whether other service-related events and demographic factors increase the risk of moral injury (MI), which is defined by consequences of highly stressful and morally-laden experiences, is poorly understood. Therefore, the objective of this study was to examine determinants of MI in Canadian Armed Forces (CAF) personnel. Methods: Data were obtained from the 2018 Canadian Armed Forces Members and Veterans Mental Health Follow-up Survey (CAFVMHS; unweighted n = 2,941). To identify military characteristics, sociodemographic variables, and deployment-related factors associated with increased levels of MI, a series of multiple linear regressions were conducted across deployed and non-deployed groups. Results: When all variables were considered among the deployed personnel, rank, experiencing military related sexual trauma, child maltreatment (i.e., physical abuse, emotional abuse and neglect), and stressful deployment experiences were significant predictors of increased MI total scores (β = 0.001 to β = 0.51, p &lt; 0.05). Feeling responsible for the death of an ally and inability to respond in a threatening situation were the strongest predictors of MI among stressful deployment experiences. Within the non-deployed sample, experiencing military-related or civilian sexual trauma and rank were significant predictors of increased MI total scores (β = 0.02 to β = 0.81, p &lt; 0.05). Conclusion: Exposure to stressful deployment experiences, particularly those involving moral-ethical challenges, sexual trauma, and childhood maltreatment were found to increase levels of MI in CAF personnel. These findings suggest several avenues of intervention, including education and policies aimed at mitigating sexual misconduct, as well as pre-deployment training to better prepare military personnel to deal effectively with morally injurious experiences.</p

    Risk Factors for Moral Injury Among Canadian Armed Forces Personnel

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    Objectives: The traumatic nature of high-risk military deployment events, such as combat, is well-recognized. However, whether other service-related events and demographic factors increase the risk of moral injury (MI), which is defined by consequences of highly stressful and morally-laden experiences, is poorly understood. Therefore, the objective of this study was to examine determinants of MI in Canadian Armed Forces (CAF) personnel. Methods: Data were obtained from the 2018 Canadian Armed Forces Members and Veterans Mental Health Follow-up Survey (CAFVMHS; unweighted n = 2,941). To identify military characteristics, sociodemographic variables, and deployment-related factors associated with increased levels of MI, a series of multiple linear regressions were conducted across deployed and non-deployed groups. Results: When all variables were considered among the deployed personnel, rank, experiencing military related sexual trauma, child maltreatment (i.e., physical abuse, emotional abuse and neglect), and stressful deployment experiences were significant predictors of increased MI total scores (β = 0.001 to β = 0.51, p &lt; 0.05). Feeling responsible for the death of an ally and inability to respond in a threatening situation were the strongest predictors of MI among stressful deployment experiences. Within the non-deployed sample, experiencing military-related or civilian sexual trauma and rank were significant predictors of increased MI total scores (β = 0.02 to β = 0.81, p &lt; 0.05). Conclusion: Exposure to stressful deployment experiences, particularly those involving moral-ethical challenges, sexual trauma, and childhood maltreatment were found to increase levels of MI in CAF personnel. These findings suggest several avenues of intervention, including education and policies aimed at mitigating sexual misconduct, as well as pre-deployment training to better prepare military personnel to deal effectively with morally injurious experiences.</p

    Moral injury associated with increased odds of past-year mental health disorders: a Canadian Armed Forces examination

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    Background: Potentially morally injurious experiences (PMIEs) are common during military service. However, it is unclear to what extent PMIEs are related to well-established adverse mental health outcomes. Objective: The objective of this study was to use a population-based survey to determine the associations between moral injury endorsement and the presence of past-year mental health disorders in Canadian Armed Forces (CAF) personnel and Veterans. Methods: Data were obtained from the 2018 Canadian Armed Forces Members and Veterans Mental Health Follow-up Survey (CAFVMHS). With a sample of 2,941 respondents, the weighted survey sample represented 18,120 active duty and 34,380 released CAF personnel. Multiple logistic regressions were used to assess the associations between sociodemographic characteristics (e.g. sex), military factors (e.g. rank), moral injury (using the Moral Injury Events Scale [MIES]) and the presence of specific mental health disorders (major depressive episode, generalized anxiety disorder, panic disorder, social anxiety disorder, PTSD, and suicidality). Results: While adjusting for selected sociodemographic and military factors, the odds of experiencing any past-year mental health disorder were 1.97 times greater (95% CI = 1.94–2.01) for each one-unit increase in total MIES score. Specifically, PTSD had 1.91 times greater odds (95% CI = 1.87–1.96) of being endorsed for every unit increase in MIES total score, while odds of past-year panic disorder or social anxiety were each 1.86 times greater (95% CI = 1.82–1.90) for every unit increase in total MIES score. All findings reported were statistically significant (p \u3c .001). Conclusion: These findings emphasize that PMIEs are robustly associated with the presence of adverse mental health outcomes among Canadian military personnel. The results of this project further underscore the necessity of addressing moral injury alongside other mental health concerns within the CAF
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