5,523 research outputs found

    Perineuronal chondroitin sulfates and semaphorin 3A regulate postnatal maturation of the vestibular circuit for gravity detection

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    Conference Theme: The Extracellular Matrix NichePoster Presentation: abstract no. P30Perineuronal chondroitin sulfate proteoglycan networks are implicated in restricting plasticity of the mature CNS. Less is known of the impact of ligands associated with the perineuronal network (PN) in the formative period of neural circuits. The emergence of negative geotaxis with postnatal maturation of the vestibular circuitry for gravity detection offers a behavioral readout in tests for roles of the PN and associated ligands in vestibular plasticity. Using postnatal rats as model, we found that negative geotaxis was mature by postnatal day (P) 9, in correlation with ...postprin

    Semaphorin3A, associated with perineuronal nets, regulates the development of the maturation of the central vestibular circuitry

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    Poster Presentation - Theme 5: NeuroscienceDuring the formative period of neural circuits, perineuronal nets (PN) are established to restrict plasticity of the circuit. The role of PN in vestibular plasticity can be tested by studying the emergence of negative geotaxis with postnatal maturation of the vestibular circuitry for gravity detection. Using rats as model, we observed that negative geotaxis was mature by postnatal day (P) 9, in correlation with consolidation of PN around GABAergic neurons …postprin

    The use of enoxaparin in Chinese patients undergoing percutaneous coronary intervention: observations on safety, efficacy, and pharmacokinetics from a pilot study

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    Protocol for a systematic review and thematic synthesis of patient experiences of central venous access devices in anti-cancer treatment

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    Background: Three types of central venous access devices (CVADs)—peripherally inserted central catheters (PICCs), skin-tunnelled central catheters (Hickman-type devices), and implantable chest wall Ports (Ports)—are routinely used in the intravenous administration of anti-cancer treatment. These devices avoid the need for peripheral cannulation and allow for home delivery of treatment. Assessments of these devices have tended to focus on medical and economic factors, but there is increased interest in the importance of patient experiences and perspectives in this area. The aim of this systematic review is to synthesise existing research regarding patient experiences of these CVADs to help clinicians guide, prepare, and support patients receiving CVADs for the administration of anti-cancer treatment. Method: A systematic search of MEDLINE, Embase, and CINAHL research databases will be carried out along with a supplementary reference list search. This review will include quantitative, qualitative, and mixed methods studies published in peer-review journals, reporting some aspect(s) of patient experiences or perspectives regarding the use of PICC, Hickman, or Port CVADs for the administration of anti-cancer drugs. The methodological quality and risk of bias of included papers will be assessed using the Mixed Methods Appraisal Tool (MMAT). Relevant outcome data will be extracted from included studies and analysed using a thematic synthesis approach. Discussion: The results section of the review will comprise thematic synthesis of quantitative studies, thematic synthesis of qualitative studies, and the aggregation of the two. Results will aim to offer an account of current understandings of patient experiences and perspective regarding PICC, Hickman-type, and Port devices in the context of anti-cancer treatment. Confidence in cumulative evidence will be assessed using the Confidence in the Evidence from Reviews of Qualitative research (CERQual) approach

    Gauge fields in (A)dS within the unfolded approach: algebraic aspects

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    It has recently been shown that generalized connections of the (A)dS space symmetry algebra provide an effective geometric and algebraic framework for all types of gauge fields in (A)dS, both for massless and partially-massless. The equations of motion are equipped with a nilpotent operator called σ\sigma_- whose cohomology groups correspond to the dynamically relevant quantities like differential gauge parameters, dynamical fields, gauge invariant field equations, Bianchi identities etc. In the paper the σ\sigma_--cohomology is computed for all gauge theories of this type and the field-theoretical interpretation is discussed. In the simplest cases the σ\sigma_--cohomology is equivalent to the ordinary Lie algebra cohomology.Comment: 59 pages, replaced with revised verio

    Changes in midbrain pain receptor expression, gait and behavioral sensitivity in a rat model of radiculopathy.

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    Intervertebral disc herniation may contribute to inflammatory processes that associate with radicular pain and motor deficits. Molecular changes at the affected dorsal root ganglion (DRG), spinal cord, and even midbrain, have been documented in rat models of radiculopathy or nerve injury. The objective of this study was to evaluate gait and the expression of key pain receptors in the midbrain in a rodent model of radiculopathy. Radiculopathy was induced by harvesting tail nucleus pulposus (NP) and placing upon the right L5 DRG in rats (NP-treated, n=12). Tail NP was discarded in sham-operated animals (n=12). Mechanical allodynia, weight-bearing, and gait were evaluated in all animals over time. At 1 and 4 weeks after surgery, astrocyte and microglial activation was tested in DRG sections. Midbrain sections were similarly evaluated for immunoreactivity to serotonin (5HT(2B)), mu-opioid (µ-OR), and metabotropic glutamate (mGluR4 and 5) receptor antibodies. NP-treated animals placed less weight on the affected limb 1 week after surgery and experienced mechanical hypersensitivity over the duration of the study. Astroctye activation was observed at DRGs only at 4 weeks after surgery. Findings for pain receptors in the midbrain of NP-treated rats included an increased expression of 5HT(2B) at 1, but not 4 weeks; increased expression of µ-OR and mGluR5 at 1 and 4 weeks (periaqueductal gray region only); and no changes in expression of mGluR4 at any point in this study. These observations provide support for the hypothesis that the midbrain responds to DRG injury with a transient change in receptors regulating pain responses

    Ordinary-derivative formulation of conformal totally symmetric arbitrary spin bosonic fields

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    Conformal totally symmetric arbitrary spin bosonic fields in flat space-time of even dimension greater than or equal to four are studied. Second-derivative (ordinary-derivative) formulation for such fields is developed. We obtain gauge invariant Lagrangian and the corresponding gauge transformations. Gauge symmetries are realized by involving the Stueckelberg and auxiliary fields. Realization of global conformal boost symmetries on conformal gauge fields is obtained. Modified de Donder gauge condition and de Donder-Stueckelberg gauge condition are introduced. Using the de Donder-Stueckelberg gauge frame, equivalence of the ordinary-derivative and higher-derivative approaches is demonstrated. On-shell degrees of freedom of the arbitrary spin conformal field are analyzed. Ordinary-derivative light-cone gauge Lagrangian of conformal fields is also presented. Interrelations between the ordinary-derivative gauge invariant formulation of conformal fields and the gauge invariant formulation of massive fields are discussed.Comment: 51 pages, v2: Results and conclusions of v1 unchanged. In Sec.3, brief review of higher-derivative approaches added. In Sec.4, new representations for Lagrangian, modified de Donder gauge, and de Donder-Stueckelberg gauge added. In Sec.5, discussion of interrelations between the ordinary-derivative and higher-derivative approaches added. Appendices A,B,C,D and references adde

    Gene expression drives the evolution of dominance.

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    Dominance is a fundamental concept in molecular genetics and has implications for understanding patterns of genetic variation, evolution, and complex traits. However, despite its importance, the degree of dominance in natural populations is poorly quantified. Here, we leverage multiple mating systems in natural populations of Arabidopsis to co-estimate the distribution of fitness effects and dominance coefficients of new amino acid changing mutations. We find that more deleterious mutations are more likely to be recessive than less deleterious mutations. Further, this pattern holds across gene categories, but varies with the connectivity and expression patterns of genes. Our work argues that dominance arises as a consequence of the functional importance of genes and their optimal expression levels

    Electrochemical synthesis of peroxomonophosphate using boron-doped diamond anodes

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    A new method for the synthesis of peroxomonophosphate, based on the use of boron-doped diamond electrodes, is described. The amount of oxidant electrogenerated depends on the characteristics of the supporting media (pH and solute concentration) and on the operating conditions (temperature and current density). Results show that the pH, between values of 1 and 5, does not influence either the electrosynthesis of peroxomonophosphate or the chemical stability of the oxidant generated. Conversely, low temperatures are required during the electrosynthesis process to minimize the thermal decomposition of peroxomonophosphate and to guarantee significant oxidant concentration. In addition, a marked influence of both the current density and the initial substrate is observed. This observation can be explained in terms of the contribution of hydroxyl radicals in the oxidation mechanisms that occur on diamond surfaces. In the assays carried out below the water oxidation potential, the generation of hydroxyl radicals did not take place. In these cases, peroxomonophosphate generation occurs through a direct electron transfer and, therefore, at these low current densities lower concentrations are obtained. On the other hand, at higher potentials both direct and hydroxyl radical-mediated mechanisms contribute to the oxidant generation and the process is more efficient. In the same way, the contribution of hydroxyl radicals may also help to explain the significant influence of the substrate concentration. Thus, the coexistence of both phosphate and hydroxyl radicals is required to ensure the generation of significant amounts of peroxomonophosphoric acid

    Understanding the nature of "superhard graphite"

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    Numerous experiments showed that on cold compression graphite transforms into a new superhard and transparent allotrope. Several structures with different topologies have been proposed for this phase. While experimental data are consistent with these models, the only way to solve this puzzle is to find which structure is kinetically easiest to form. Using state-of-the-art molecular-dynamics transition path sampling simulations, we investigate kinetic pathways of the pressure-induced transformation of graphite to various superhard candidate structures. Unlike hitherto applied methods for elucidating nature of superhard graphite, transition path sampling realistically models nucleation events necessary for physically meaningful transformation kinetics. We demonstrate that nucleation mechanism and kinetics lead to MM-carbon as the final product. WW-carbon, initially competitor to MM-carbon, is ruled out by phase growth. Bct-C4_4 structure is not expected to be produced by cold compression due to less probable nucleation and higher barrier of formation
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