Ground State Energy of the Polaron in the Relativistic Quantum Electrodynamics

We consider the polaron model in the relativistic quantum electrodynamics( QED). We prove that the ground state energy of the model is finite for all values of the fine-structure constant and the ultraviolet cutoff $\Lambda$. Moreover we give an upper bound and a lower bound of the ground state energy

Comparison and nuclearity of spaces of differential forms on topological vector spaces

Two types of fundamental spaces of differential forms on infinite dimensional topological vector spaces are considered; one is a fundamental space of Hida's type and the other is one of Malliavin's. It is proven that the former space is smaller than the latter. Moreover, it is shown that, under some conditions, the fundamental space of Hida's type is nuclear as a complete countably normed space, while that of Malliavin's in the L2 sense is not

Synaptotagmin 2 is the fast Ca2+ sensor at a central inhibitory synapse

GABAergic synapses in brain circuits generate inhibitory output signals with submillisecond latency and temporal precision. Whether the molecular identity of the release sensor contributes to these signaling properties remains unclear. Here, we examined the Ca^2+ sensor of exocytosis at GABAergic basket cell (BC) to Purkinje cell (PC) synapses in cerebellum. Immunolabeling suggested that BC terminals selectively expressed synaptotagmin 2 (Syt2), whereas synaptotagmin 1 (Syt1) was enriched in excitatory terminals. Genetic elimination of Syt2 reduced action potential-evoked release to ∼10%, identifying Syt2 as the major Ca^2+ sensor at BC-PC synapses. Differential adenovirus-mediated rescue revealed that Syt2 triggered release with shorter latency and higher temporal precision and mediated faster vesicle pool replenishment than Syt1. Furthermore, deletion of Syt2 severely reduced and delayed disynaptic inhibition following parallel fiber stimulation. Thus, the selective use of Syt2 as release sensor at BC-PC synapses ensures fast and efficient feedforward inhibition in cerebellar microcircuits. #bioimagingfacility-autho

One-year follow-up for the therapeutic efficacy of pregabalin in patients with leg symptoms caused by lumbar spinal stenosis

AbstractBackground Pregabalin is a well-accepted treatment option for patients with neuropathic pain. However, the therapeutic efficacy of pregabalin for reducing the incidence of spinal surgery to treat leg symptoms in patients with lumbar spinal stenosis remains unknown. The purpose of this study was to analyze the therapeutic efficacy of pregabalin for reducing the incidence of spinal surgery for leg symptoms in patients with lumbar spinal stenosis during the first year of treatment.Methods Consecutive patients diagnosed with lumbar spinal stenosis at our hospital from January to June 2009 were treated with nonsteroidal anti-inflammatory drug monotherapy and formed the control group (n = 47; 22 males, 25 females). Patients diagnosed with lumbar spinal stenosis at our hospital between August 2010 and October 2011 were treated with a nonsteroidal anti-inflammatory drug and pregabalin combination therapy and formed the pregabalin group (n = 49; 27 males, 22 females). The proportions of patients who underwent spinal surgery during the first year of treatment were assessed and compared between the two groups using the Mann-Whitney U test. In addition, the periods in which patients decided to undergo spinal surgery were compared using the Kaplan-Meier method.Results Six patients (12.2 %) in the pregabalin group and 22 patients (46.8 %) in the control group underwent spinal surgery during the first year of treatment (P = 0.0035). The period in which patients decided to undergo spinal surgery was significantly delayed in the pregabalin group compared with the control group in those for whom spinal surgery was necessary (P = 0.0128).Conclusions Nonsteroidal anti-inflammatory drug and pregabalin combination therapy may result in a lower incidence of spinal surgery during the first year of treatment or a delayed period before undergoing spinal surgery if necessary compared with nonsteroidal anti-inflammatory drug monotherapy in patients with leg symptoms caused by lumbar spinal stenosis

Chemical labelling for visualizing native AMPA receptors in live neurons

The location and number of neurotransmitter receptors are dynamically regulated at postsynaptic sites. However, currently available methods for visualizing receptor trafficking require the introduction of genetically engineered receptors into neurons, which can disrupt the normal functioning and processing of the original receptor. Here we report a powerful method for visualizing native α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors (AMPARs) which are essential for cognitive functions without any genetic manipulation. This is based on a covalent chemical labelling strategy driven by selective ligand-protein recognition to tether small fluorophores to AMPARs using chemical AMPAR modification (CAM) reagents. The high penetrability of CAM reagents enables visualization of native AMPARs deep in brain tissues without affecting receptor function. Moreover, CAM reagents are used to characterize the diffusion dynamics of endogenous AMPARs in both cultured neurons and hippocampal slices. This method will help clarify the involvement of AMPAR trafficking in various neuropsychiatric and neurodevelopmental disorders

Interfacial fracture strength property of micro-scale SiN/Cu components

AbstractThe strength against fracture nucleation from an interface free-edge of silicon-nitride (SiN)/copper (Cu) micro-components is evaluated. A special technique that combines a nano-indenter specimen holder and an environmental transmission electron microscope (E-TEM) is employed. The critical load at the onset of fracture nucleation from a wedge-shaped free-edge (opening angle: 90°) is measured both in a vacuum and in a hydrogen (H2) environment, and the critical stress distribution is evaluated by the finite element method (FEM). It is found that the fracture nucleation is dominated by the near-edge elastic singular stress field that extends about a few tens of nanometers from the edge. The fracture nucleation strength expressed in terms of the stress intensity factor (K) is found to be eminently reduced in a H2 environment

Structural aging of human neurons is the opposite of the changes in schizophrenia

Human mentality develops with age and is altered in psychiatric disorders, though their underlying mechanism is unknown. In this study, we analyzed nanometer-scale three-dimensional structures of brain tissues of the anterior cingulate cortex from eight schizophrenia and eight control cases. The distribution profiles of neurite curvature of the control cases showed a trend depending on their age, resulting in an age-correlated decrease in the standard deviation of neurite curvature (Pearson's r = -0.80, p = 0.018). In contrast to the control cases, the schizophrenia cases deviate upward from this correlation, exhibiting a 60% higher neurite curvature compared with the controls (p = 7.8 x 10^(-4)). The neurite curvature also showed a correlation with a hallucination score (Pearson's r = 0.80, p = 1.8 x 10^(-4)), indicating that neurite structure is relevant to brain function. We suggest that neurite curvature plays a pivotal role in brain aging and can be used as a hallmark to exploit a novel treatment of schizophrenia. This nano-CT paper is the result of our decade-long analysis and is unprecedented in terms of number of cases.Comment: 24 pages, 5 figures. arXiv admin note: text overlap with arXiv:2007.0021

Reconstitution of DNA Strand Exchange Mediated by Rhp51 Recombinase and Two Mediators

In the fission yeast Schizosaccharomyces pombe, genetic evidence suggests that two mediators, Rad22 (the S. pombe Rad52 homolog) and the Swi5-Sfr1 complex, participate in a common pathway of Rhp51 (the S. pombe Rad51 homolog)–mediated homologous recombination (HR) and HR repair. Here, we have demonstrated an in vitro reconstitution of the central step of DNA strand exchange during HR. Our system consists entirely of homogeneously purified proteins, including Rhp51, the two mediators, and replication protein A (RPA), which reflects genetic requirements in vivo. Using this system, we present the first robust biochemical evidence that concerted action of the two mediators directs the loading of Rhp51 onto single-stranded DNA (ssDNA) precoated with RPA. Dissection of the reaction reveals that Rad22 overcomes the inhibitory effect of RPA on Rhp51-Swi5-Sfr1–mediated strand exchange. In addition, Rad22 negates the requirement for a strict order of protein addition to the in vitro system. However, despite the presence of Rad22, Swi5-Sfr1 is still essential for strand exchange. Importantly, Rhp51, but neither Rad22 nor the Swi5-Sfr1 mediator, is the factor that displaces RPA from ssDNA. Swi5-Sfr1 stabilizes Rhp51-ssDNA filaments in an ATP-dependent manner, and this stabilization is correlated with activation of Rhp51 for the strand exchange reaction. Rad22 alone cannot activate the Rhp51 presynaptic filament. AMP-PNP, a nonhydrolyzable ATP analog, induces a similar stabilization of Rhp51, but this stabilization is independent of Swi5-Sfr1. However, hydrolysis of ATP is required for processive strand transfer, which results in the formation of a long heteroduplex. Our in vitro reconstitution system has revealed that the two mediators have indispensable, but distinct, roles for mediating Rhp51 loading onto RPA-precoated ssDN