1,493 research outputs found

    Inhibitory postsynaptic actions of taurine, GABA and other amino acids on motoneurons of the isolated frog spinal cord

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    The actions of glycine, GABA, α-alanine, β-alanine and taurine were studied by intracellular recordings from lumbar motoneurons of the isolated spinal cord of the frog. All amino acids tested produced a reduction in the amplitude of postsynaptic potentials, a blockade of the antidromic action potential and an increase of membrane conductance. Furthermore, membrane polarizations occurred, which were always in the same direction as the IPSP. All these effects indicate a postsynaptic inhibitory action of these amino acids. When the relative strength of different amino acids was compared, taurine had the strongest inhibitory potency, followed by β-alanine, α α-alanine, GABA and glycine. Topically applied strychnine and picrotoxin induced different changes of postsynaptic potentials, indicating that distinct inhibitory systems might be influenced by these two convulsants. Interactions with amino acids showed that picrotoxin selectively diminished the postsynaptic actions of GABA, while strychnine reduced the effects of taurine, glycine, α- and β-alanine. But differences in the susceptibility of these amino acid actions to strychnine could be detected: the action of taurine was more sensitively blocked by strychnine compared with glycine, α- and β-alanine. With regard to these results the importance of taurine and GABA as transmitters of postsynaptic inhibition on motoneurons in the spinal cord of the frog is discussed

    Entangled networks, synchronization, and optimal network topology

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    A new family of graphs, {\it entangled networks}, with optimal properties in many respects, is introduced. By definition, their topology is such that optimizes synchronizability for many dynamical processes. These networks are shown to have an extremely homogeneous structure: degree, node-distance, betweenness, and loop distributions are all very narrow. Also, they are characterized by a very interwoven (entangled) structure with short average distances, large loops, and no well-defined community-structure. This family of nets exhibits an excellent performance with respect to other flow properties such as robustness against errors and attacks, minimal first-passage time of random walks, efficient communication, etc. These remarkable features convert entangled networks in a useful concept, optimal or almost-optimal in many senses, and with plenty of potential applications computer science or neuroscience.Comment: Slightly modified version, as accepted in Phys. Rev. Let

    Lessons from the Development of an Anomaly Detection Interface on the Mars Perseverance Rover using the ISHMAP Framework

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    While anomaly detection stands among the most important and valuable problems across many scientific domains, anomaly detection research often focuses on AI methods that can lack the nuance and interpretability so critical to conducting scientific inquiry. In this application paper we present the results of utilizing an alternative approach that situates the mathematical framing of machine learning based anomaly detection within a participatory design framework. In a collaboration with NASA scientists working with the PIXL instrument studying Martian planetary geochemistry as a part of the search for extra-terrestrial life; we report on over 18 months of in-context user research and co-design to define the key problems NASA scientists face when looking to detect and interpret spectral anomalies. We address these problems and develop a novel spectral anomaly detection toolkit for PIXL scientists that is highly accurate while maintaining strong transparency to scientific interpretation. We also describe outcomes from a yearlong field deployment of the algorithm and associated interface. Finally we introduce a new design framework which we developed through the course of this collaboration for co-creating anomaly detection algorithms: Iterative Semantic Heuristic Modeling of Anomalous Phenomena (ISHMAP), which provides a process for scientists and researchers to produce natively interpretable anomaly detection models. This work showcases an example of successfully bridging methodologies from AI and HCI within a scientific domain, and provides a resource in ISHMAP which may be used by other researchers and practitioners looking to partner with other scientific teams to achieve better science through more effective and interpretable anomaly detection tools

    Publication guidelines for quality improvement in health care: evolution of the SQUIRE project

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    In 2005, draft guidelines were published for reporting studies of quality improvement interventions as the initial step in a consensus process for development of a more definitive version. This article contains the full revised version of the guidelines, which the authors refer to as SQUIRE (Standards for QUality Improvement Reporting Excellence). This paper also describes the consensus process, which included informal feedback from authors, editors and peer reviewers who used the guidelines; formal written commentaries; input from a group of publication guideline developers; ongoing review of the literature on the epistemology of improvement and methods for evaluating complex social programmes; a two-day meeting of stakeholders for critical discussion and debate of the guidelines’ content and wording; and commentary on sequential versions of the guidelines from an expert consultant group. Finally, the authors consider the major differences between SQUIRE and the initial draft guidelines; limitations of and unresolved questions about SQUIRE; ancillary supporting documents and alternative versions that are under development; and plans for dissemination, testing and further development of SQUIRE

    Comment on the Definition of Eligible Organization for Purposes of Coverage of Certain Preventive Services Under the Affordable Care Act

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    This comment letter was submitted by U.C. Berkeley corporate law professors in response to a request for comment by the Health and Human Services Department on the definition of eligible organization under the Affordable Care Act in light of the Supreme Court\u27s decision in Burwell v. Hobby Lobby. Eligible organizations will be permitted under the Hobby Lobby decision to assert the religious principles of their shareholders to exempt themselves from the Affordable Care Act\u27s contraceptive mandate for employees. In Hobby Lobby, the Supreme Court held that the nexus of identity between several closely-held, for-profit corporations and their shareholders holding “a sincere religious belief that life begins at conception” was sufficiently close to justify granting such corporations an exemption from the Affordable Care Act\u27s contraceptive mandate pursuant to the Religious Freedom Restoration Act of 1993. More specifically, the Court ascertained that the overall interests of the corporations and their natural-person shareholders were sufficiently identical to warrant ascribing the religious commitments of the shareholders to their corporations. Notably, the Court stopped short of articulating a diagnostic test for determining when a sufficient overlap of interests exists; instead, it concluded that well-established principles in state corporate law should provide such guidance. We believe that state corporate law does in fact provide the diagnostic test the Court desires for determining when it is appropriate to disregard the distinct identity of a corporation for the identity of its shareholders. This test is rooted in the long-standing case law that constitutes the alter ego doctrine (commonly referred to as “veil piercing”). To sustain a claim of veil piercing, state corporate law uniformly requires there to be “unity of ownership and interest” between the corporation and its shareholders. If a corporation is operated as the effective alter ego of its shareholders to such an extent that its separate corporate existence ceases to exist as a practical matter, then a veil piercing claim can be established that effectively attributes the corporation’s legal rights and obligations to its shareholders, and vice versa. A veil piercing conclusion effectively holds that there is no practical difference between the corporation and the shareholders themselves. We therefore propose that for purposes of defining an “eligible organization” under Hobby Lobby, the HHS and other federal organizations should follow the corporate law doctrine of veil piercing. Indeed, to make this doctrine administratively feasible, we further suggest that shareholders of a corporation should have to certify that they and the corporation have a unity in identity and interests, and therefore the corporation should be viewed as the shareholders’ alter ego

    Changes of intracellular sodium and potassium ion concentrations in frog spinal motoneurons induced by repetitive synaptic stimulation

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    A post-tetanic membrane hyperpolarization following repetitive neuronal activity is a commonly observed phenomenon in the isolated frog spinal cord as well as in neurons of other nervous tissues. We have now used double-barrelled Na+- and K+-ion-sensitive microelectrodes to measure the intracellular Na+- and K+-concentrations and also the extracellular K+-concentration of lumbar spinal motoneurons during and after repetitive stimulation of a dorsal root. The results show that the posttetanic membrane hyperpolarization occurred at a time when the intracellular [Na+] reached its maximal value, intracellular [K+] had its lowest level and extracellular [K+] was still elevated. The hyperpolarization was blocked by ouabain and reduced by Li+. These data support the previous suggestion that an electrogenic Na+/K+ pump mode may be the mechanism underlying the post-tetanic membrane hyperpolarization

    Gestational age at delivery and special educational need: retrospective cohort study of 407,503 schoolchildren

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    <STRONG>Background</STRONG> Previous studies have demonstrated an association between preterm delivery and increased risk of special educational need (SEN). The aim of our study was to examine the risk of SEN across the full range of gestation. <STRONG>Methods and Findings</STRONG> We conducted a population-based, retrospective study by linking school census data on the 407,503 eligible school-aged children resident in 19 Scottish Local Authority areas (total population 3.8 million) to their routine birth data. SEN was recorded in 17,784 (4.9%) children; 1,565 (8.4%) of those born preterm and 16,219 (4.7%) of those born at term. The risk of SEN increased across the whole range of gestation from 40 to 24 wk: 37–39 wk adjusted odds ratio (OR) 1.16, 95% confidence interval (CI) 1.12–1.20; 33–36 wk adjusted OR 1.53, 95% CI 1.43–1.63; 28–32 wk adjusted OR 2.66, 95% CI 2.38–2.97; 24–27 wk adjusted OR 6.92, 95% CI 5.58–8.58. There was no interaction between elective versus spontaneous delivery. Overall, gestation at delivery accounted for 10% of the adjusted population attributable fraction of SEN. Because of their high frequency, early term deliveries (37–39 wk) accounted for 5.5% of cases of SEN compared with preterm deliveries (<37 wk), which accounted for only 3.6% of cases. <STRONG>Conclusions</STRONG> Gestation at delivery had a strong, dose-dependent relationship with SEN that was apparent across the whole range of gestation. Because early term delivery is more common than preterm delivery, the former accounts for a higher percentage of SEN cases. Our findings have important implications for clinical practice in relation to the timing of elective delivery

    Severe renal bleeding caused by a ruptured renal sheath: case report of a rare complication of percutaneous nephrolithotomy

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    BACKGROUND: Percutaneous nephrolithotomy is a minimally invasive intervention for renal stone disease. Complications, which are rare and usually presented as case reports, are diversified as the utilization of the procedure is expanded. The procedure causes less blood loss and less morbidity when compared to open surgical procedures. Yet, there are some reports involving severe bleeding and relevant morbidity during surgery. These are usually related with the surgical technique or experience of the surgeon. Renal sheaths are designed to cause minimal trauma inside the kidney and, to our knowledge, there are no reports presenting the rupture of a sheath causing severe bleeding during the procedure. CASE REPORT: We present an adult patient who had severe bleeding during percutaneous nephrolithotomy due to parenchymal injury caused by a ruptured renal sheath. During retrieval, due probably to rough handling of the equipment, a piece of stone with serrated edges ruptured the tip of the sheath, and this tip caused damage inside the kidney. The operation was terminated and measures were taken to control bleeding. The patient was transfused with a total of 1600 ml of blood, and the stones were cleared in a second look operation. CONCLUSION: Although considered to be a minimally invasive procedure, some unexpected complications may arise during percutaneous nephrolithotomy. After being fragmanted, stone pieces may damage surgical equipment, causing acute and severe harm to the kidney. Surgeons must manipulate the equipment with fine and careful movements in order to prevent this situation

    Lithium distribution across the membrane of motoneurons in the isolated frog spinal cord

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    Lithium sensitive microelectrodes were used to investigate the transmembrane distribution of lithium ions (Li+) in motoneurons of the isolated frog spinal cord. After addition of 5 mmol·l–1 LiCl to the bathing solution the extracellular diffusion of Li+ was measured. At a depth of 500 m, about 60 min elapsed before the extracellular Li+ concentration approached that of the bathing solution. Intracellular measurements revealed that Li+ started to enter the cells soon after reaching the motoneuron pool and after up to 120 min superfusion, an intra — to extracellular concentration ratio of about 0.7 was obtained. The resting membrane potential and height of antidromically evoked action potentials were not altered by 5 mmol·l–1 Li+
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