547 research outputs found

    The basic chemistry of exercise-induced DNA oxidation:oxidative damage, redox signalling and their interplay

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    Acute exercise increases reactive oxygen and nitrogen species generation. This phenomenon is associated with two major outcomes: (1) redox signalling and (2) macromolecule damage. Mechanistic knowledge of how exercise-induced redox signalling and macromolecule damage are interlinked is limited. This review focuses on the interplay between exercise-induced redox signalling and DNA damage, using hydroxyl radical (·OH) and hydrogen peroxide (H2O2) as exemplars. It is postulated that the biological fate of H2O2 links the two processes and thus represents a bifurcation point between redox signalling and damage. Indeed, H2O2 can participate in two electron signalling reactions but its diffusion and chemical properties permit DNA oxidation following reaction with transition metals and ·OH generation. It is also considered that the sensing of DNA oxidation by repair proteins constitutes a non-canonical redox signalling mechanism. Further layers of interaction are provided by the redox regulation of DNA repair proteins and their capacity to modulate intracellular H2O2 levels. Overall, exercise-induced redox signalling and DNA damage may be interlinked to a greater extent than was previously thought but this requires further investigation

    Editorial: Psychophysiology of Stress

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    Stress is a multifactorial complex phenomenon where organic resources are mobilized to deal with a real or perceived threat (Cohen et al., 1983). The stress response is one of the most important phylogenetic coping mechanisms that have allowed humans to successfully adapt to highly demanding and potentially dangerous contexts (Hadany et al., 2006; Korzan and Summers, 2021). The intrinsic neurobiological mechanisms involved in the stress response have not changed much in the last stages of the evolution of the human being, prominently including the hypothalamic-pituitary-adrenocortical axis and the autonomic nervous system (Ulrich-Lai and Herman, 2009;McEwen et al., 2015; Cohen et al., 2016). In contrast, our social context has changed dramatically recently in evolutionary terms

    Management of intestinal transplantation in humans

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    We report here the clinical experience and management guidelines for the nine consecutive cases who received either an isolated small intestinal graft (n = 1) or an intestine liver combination at the University of Pittsburgh, with FK 506 being the basic immunosuppressive drug therapy

    Principles for integrating reactive species into in vivo biological processes:examples from exercise physiology

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    The equivocal role of reactive species and redox signaling in exercise responses and adaptations is an example clearly showing the inadequacy of current redox biology research to shed light on fundamental biological processes in vivo. Part of the answer probably relies on the extreme complexity of the in vivo redox biology and the limitations of the currently applied methodological and experimental tools. We propose six fundamental principles that should be considered in future studies to mechanistically link reactive species production to exercise responses or adaptations: 1) identify and quantify the reactive species, 2) determine the potential signaling properties of the reactive species, 3) detect the sources of reactive species, 4) locate the domain modified and verify the (ir)reversibility of post-translational modifications, 5) establish causality between redox and physiological measurements, 6) use selective and targeted antioxidants. Fulfilling these principles requires an idealized human experimental setting, which is certainly a utopia. Thus, researchers should choose to satisfy those principles, which, based on scientific evidence, are most critical for their specific research question

    An edge-queued datagram service for all datacenter traffic

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    Modern datacenters support a wide range of protocols and in-network switch enhancements aimed at improving performance. Unfortunately, the resulting protocols often do not coexist gracefully because they inevitably interact via queuing in the network. In this paper we describe EQDS, a new datagram service for datacenters that moves almost all of the queuing out of the core network and into the sending host. This enables it to support multiple (conflicting) higher layer protocols, while only sending packets into the network according to any receiver-driven credit scheme. EQDS can transparently speed up legacy TCP and RDMA stacks, and enables transport protocol evolution, while benefiting from future switch enhancements without needing to modify higher layer stacks. We show through simulation and multiple implementations that EQDS can reduce FCT of legacy TCP by 2x, improve the NVMeOF-RDMA throughput by 30%, and safely run TCP alongside RDMA on the same network

    Development of a screening tool enabling identification of infants and toddlers at risk for family abuse and neglect : A feasibility study from three South European countries

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    Background: Child abuse is a health and social problem, and few screening instruments are available for the detection of risk in primary health care. The aim was to develop a screening instrument to be used by professionals in the public health care sector, thus enabling the detection of infants and toddlers at risk of emotional and physical abuse and neglect, and to provide evidence for the feasibility of the instrument in Cyprus, Greece and Spain. Method: A total of 50 health professionals from paediatric public health-care centres in the three countries were involved in a three-step process for guiding the development of the screening tool and its application. Results: A nine-item screening tool, consisting of items assessing relational emotional abuse, physical abuse and other risk factors, was developed. The screening tool was applied on a total of 219 families with 0 to 3-year-old children attending public health centres in the three countries. Clinicians reported that they agreed on the inclusion of the questions (86.4-100%) and that they found the questions to be useful for the clinical evaluation of the family (63.2-100%). Conclusion: The screening tool shows considerable face validity and was reported feasible by an international set of clinician

    Factors associated with perceived performance drops and musculoskeletal injuries in Brazilian recreational triathletes

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    OBJECTIVE The aim of the study was to investigate sleep characteristics, use of supplements, and training volume of recreational triathletes, and to verify possible associations with perceived performance drops and occurrence of injuries. MATERIALS AND METHODS Recreational triathletes (n=942) answered a questionnaire inquiring about their demographic characteristics, performance, injuries and training volume. RESULTS When comparing athletes who slept more (9-10 hours) with those who slept less, less sleep was associated with a higher prevalence of perceived performance drops. Regarding difficulties in initiating sleep, the absence of initiating difficulties (p<0.001) was a protective factor against perceived performance drops. Regarding weekly training volume, compared to those who trained more than 20 hours, training less than 3 hours (p<0.001), 3-5 hours (p<0.001), or 12-14 hours (p<0.001) were protective factors against perceived performance drops. Concerning training volume and injuries, we found that compared to those who trained more than 20 hours, training 18-20 hours (p<0.001), 15-17 hours (p<0.001), 12-14 hours (p<0.001), 6-8 hours (p<0.001), or 3-5 hours (p<0.001) were protective factors against injuries. CONCLUSIONS Triathletes with a lower sleep quantity and those who have difficulties initiating sleep frequently experience drops in performance. Training volumes can influence both performance and the likelihood of injuries

    Robusna procedura za umetanje vodenog ┼żiga u sliku zasnovana na Hermitovoj projekcijskoj metodi

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    A procedure for combined image watermarking and compression, based on the Hermite projection method is proposed. The Hermite coefficients obtained by using the Hermite expansion are used for watermark embedding. The image can be efficiently reconstructed by using a set of Hermite coefficients that is quite smaller than the number of original ones. Hence, the watermark embedding is actually done in the compressed domain, while maintaining still high image quality (measured by high PSNR). The efficiency of the proposed procedure is proven experimentally, showing high robustness even for very strong standard attacks. Moreover, the method is robust not only to the standard attacks, but to the geometrical attacks, as well. The proposed approach can be suitable for different copyright and ownership protection purposes, especially in real-applications that require image compression, such as multimedia and Internet applications, remote sensing and satellite imaging.U radu je predlo┼żena procedura za umetanje vodenog ┼żiga u sliku i kompresiju slike zasnovana na Hermitovoj projekcijskoj metodi. Odgovaraju─çi koeficijenti, dobiveni kao rezultat primjene razvoja slike u red Hermitovih funkcija, kori┼íteni su za umetanje vodenog ┼żiga watermark). S obzirom na to da se slika mo┼że efikasno rekonstruirati kori┼ítenjem znatno manjeg broja Hermitovih koeficijenata u odnosu na broj originalnih koeficijenata slike, umetanje vodenog ┼żiga zapravo je provedeno u domeni kompresije, uz o─Źuvanje visoke kvalitete slike (velika vrijednost PSNR). U─Źinkovitost predlo┼żene procedure ispitana je eksperimentalno i pokazuje zna─Źajnu otpornost na uobi─Źajene napade. Osim uobi─Źajenih, procedura pokazuje robusnost i na geometrijske napade. Predlo┼żeni pristup mo┼że biti kori┼íten u razli─Źitim aplikacijama za za┼ítitu autorskih prava, naro─Źito u aplikacijama koje ujedno zahtijevaju i kompresiju slike, kao ┼íto su multimedijske i internetske aplikacije, daljinsko o─Źitavanje podataka i satelitska snimanja
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