5,708,750 research outputs found

    Somatosensory tinnitus: current evidence and future perspectives

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    In some individuals, tinnitus can be modulated by specific maneuvers of the temporomandibular joint, head and neck, eyes, and limbs. Neuroplasticity seems to play a central role in this capacity for modulation, suggesting that abnormal interactions between the sensory modalities, sensorimotor systems, and neurocognitive and neuroemotional networks may contribute to the development of somatosensory tinnitus. Current evidence supports a link between somatic disorders and higher modulation of tinnitus, especially in patients with a normal hearing threshold. Patients with tinnitus who have somatic disorders seems to have a higher chance of modulating their tinnitus with somatic maneuvers; consistent improvements in tinnitus symptoms have been observed in patients with temporomandibular joint disease following targeted therapy for temporomandibular disorders. Somatosensory tinnitus is often overlooked by otolaryngologists and not fully investigated during the diagnostic process. Somatic disorders, when identified and treated, can be a valid therapeutic target for tinnitus; however, somatic screening of subjects for somatosensory tinnitus is imperative for correct selection of patients who would benefit from a multidisciplinary somatic approach

    Culture, Mind, and the Brain: Current Evidence and Future Directions

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    Current research on culture focuses on independence and interdependence and documents numerous East-West psychological differences, with an increasing emphasis placed on cognitive mediating mechanisms. Lost in this literature is a time-honored idea of culture as a collective process composed of cross-generationally transmitted values and associated behavioral patterns (i.e., practices). A new model of neuro-culture interaction proposed here addresses this conceptual gap by hypothesizing that the brain serves as a crucial site that accumulates effects of cultural experience, insofar as neural connectivity is likely modified through sustained engagement in cultural practices. Thus, culture is “embrained,” and moreover, this process requires no cognitive mediation. The model is supported in a review of empirical evidence regarding (a) collective-level factors involved in both production and adoption of cultural values and practices and (b) neural changes that result from engagement in cultural practices. Future directions of research on culture, mind, and the brain are discussed

    Current Account Adjustment: Some New Theory and Evidence

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    This paper aims to provide a theory of current account adjustment that generalizes the textbook version of the intertemporal approach to current account and places domestic labor market institutions at the center stage. In general, in response to a shock, an economy adjusts through a combination of a change in the composition of goods trade (i.e., intra-temporal trade channel) and a change in the current account (i.e., intertemporal trade channel). The more rigid the labor market, the slower the speed of adjustment of the current account towards its long-run equilibrium. Three pieces of evidence are provided that are consistent with the theory.

    Role of acetaldehyde in alcohol addiction : current evidence and future perspectives

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    The effects of alcohol have been widely studied during the past century, corroborating the idea that this tiny chemical compound acts throughout most of our neurotransmitter systems since it is capable of inducing addictive behaviour. Two of the most serious problems of alcohol addiction are craving and relapse; several studies have demonstrated that relapse is related to the anxious state which occurs during withdrawal, and it has been proved that this behavioural modifications results from an alteration of the dopaminergic and serotonergic systems. An important role in the neurobiology of alcohol addiction is played by acetaldehyde (ACD), ethanol first metabolite. Our recent studies indeed, have demonstrated that ACD itself is able to induce CRH release from hypothalamic explants, underlying the central role played by ACD in alcohol-induced modifications of the HPA axis. Moreover, for the first time, this group has shown that ACD is able to induce and maintain an operant drinking behaviour after repeated abstinence periods, and in the presence of a conflict situation in rats, mimicking the same characteristics as alcohol. ACD is produced either peripherally or within the brain by alcohol dehydrogenase and catalase, respectively. Studies assert that the highest concentrations of catalase in the brain are mainly located in aminergic neurons suggesting that ACD could take part in alcohol action in those circuitries. Further investigations are then necessary to fully understand the molecular mechanisms underlying the neurochemical and behavioural modifications induced by ACD, as a mediator of alcohol activity in the brain.peer-reviewe

    The relationships between vitamin K and cognition: a review of current evidence

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    Vitamin K is a fat-soluble nutrient discovered in 1935 and its role in blood coagulation has been thoroughly explored. In recent years, studies conducted in vitro and on animals highlighted vitamin K involvement in brain cells development and survival. In particular, vitamin K seems to have an antiapoptotic and anti-inflammatory effect mediated by the activation of Growth Arrest Specific Gene 6 and Protein S. Moreover, this vitamin is involved in sphingolipids metabolism, a class of lipids that participate in the proliferation, differentiation, and survival of brain cells. An altered expression in sphingolipids profile has been related to neuroinflammation and neurodegeneration. This review stems from a growing interest in the role of vitamin K in brain functions, especially in cognition, also in view of an expected increase of prevalence of Alzheimer's disease and other forms of dementia. It collects recent researches that show interesting, even though not definitive, evidence of a direct correlation between vitamin K levels and cognitive performance. Moreover, vitamin K antagonists, used worldwide as oral anticoagulants, according to recent studies may have a negative influence on cognitive domains such as visual memory, verbal fluency and brain volume. The aim of this review is to analyze the evidence of clinical studies carried out up to date on the relationship between vitamin K intake and cognitive performances. The involvement of vitamin K antagonists (VKAs) in declining cognitive performances is also addressed separately

    The Intertemporal Approach to the Current Account: Evidence from Argentina.

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    In this paper, an intertemporal model is used to analyze the current account and test whether it accounts for the evolution of the Argentinean current account over the period extending from 1855 to 2002. The intertemporal model presented here takes into account several sources of external shocks for small economies such as a change of the real interest rate and the real exchange rate. Evidence shows that the intertemporal model does not pass the statistical tests and does not explain the Argentinean experience. More specifically, if the Argentinean current account was to behave as the model predicts, one would observe the opposite movement to that observed for the actual current account. Our main conjecture about the weak performance of the model is related to i) the fact that one of its most important assumption is violated for some part of the period under consideration (1931 - 1989); and ii) that the balance of payments’ crises and stop and go cycles may have altered the relation between the variables suggested by the model. To cope with this problem, we have estimated a model for the period 1885-1930 (a period with relatively high capital mobility and with neither currency crises nor stop and go cycles) and found some evidence in favour of this result. A general conclusion to be drawn is that, in contrast to other Latin American countries, an intertemporal current account model can not appropriately account for the dynamics of the current account of Argentina, even thought there is some evidence in favour of the model for the period 1885-1930.

    Evidence for an anomalous current phase relation in topological insulator Josephson junctions

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    Josephson junctions with topological insulator weak links can host low energy Andreev bound states giving rise to a current phase relation that deviates from sinusoidal behaviour. Of particular interest are zero energy Majorana bound states that form at a phase difference of π\pi. Here we report on interferometry studies of Josephson junctions and superconducting quantum interference devices (SQUIDs) incorporating topological insulator weak links. We find that the nodes in single junction diffraction patterns and SQUID oscillations are lifted and independent of chemical potential. At high temperatures, the SQUID oscillations revert to conventional behaviour, ruling out asymmetry. The node lifting of the SQUID oscillations is consistent with low energy Andreev bound states exhibiting a nonsinusoidal current phase relation, coexisting with states possessing a conventional sinusoidal current phase relation. However, the finite nodal currents in the single junction diffraction pattern suggest an anomalous contribution to the supercurrent possibly carried by Majorana bound states, although we also consider the possibility of inhomogeneity.Comment: 6 pages, 4 figure

    Glutamine in critical care:current evidence from systematic reviews

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    Glutamine, the most abundant amino acid in the body, is thought to become conditionally essential in critical illness. Some of the important roles for glutamine are as a carrier for inter-organ N, a preferred fuel for enterocytes and cells of the immune system, a substrate for renal NH3 formation and a precursor for glutathione. Mechanisms by which glutamine could improve recovery include attenuating oxidant damage and inflammatory cytokine production, reducing gut bacterial translocation and improving N balance. The present systematic review has found trends to suggest that parenteral and enteral glutamine supplementation reduce mortality, the development of infection and organ failure in critical illness. Trials of parenteral nutrition containing glutamine with patients after elective surgery also suggest reduction of infection, but it is unlikely that glutamine-containing parenteral nutrition would be used for such patients. The evidence base is limited by the quality of the reported trials and the suggestion that there is publication bias, with trials suggesting reduced infection being more likely to be published
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