127,697 research outputs found
T-type Ca2+ channels in absence epilepsy
No full textAbsence epilepsy accompanies the paroxysmal oscillations
in the thalamocortical circuit referred as spike and
wave discharges (SWDs). Low-threshold burst firing mediated
by T-type Ca2+ channels highly expressed in both inhibitory
thalamic reticular nuclei (TRN) and excitatory
thalamocortical (TC) neurons has been correlated with the
generation of SWDs. A generally accepted view has been that
rhythmic burst firing mediated by T-type channels in both
TRN and TC neurons are equally critical in the generation
of thalamocortical oscillations during sleep rhythms and
SWDs. This review examined recent studies on the T-type
channels in absence epilepsy which leads to an idea that even
though both TRN and TC nuclei are required for
thalamocortical oscillations, the contributions of T-type channels
to TRN and TC neurons are not equal in the genesis of
sleep spindles and SWDs. Accumulating evidence revealed a
crucial role of TC T-type channels in SWD generation. However,
the role of TRN T-type channels in SWD generation
remains controversial. Therefore, a deeper understanding of
the functional consequences of modulating each T-type channel
subtype could guide the development of therapeutic tools
for absence seizures while minimizing side effects on physiological
thalamocortical oscillations.1771sciescopu
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Creating walk-through images from a video sequence of a dynamic scene
No full textTour into the picture (TIP), proposed by Horry et al. (Horry, Anjyo, & Andi, 1997, ACM SIGGRAPH '97 Conference Proceedings, 225-232) is a method for generating a sequence of walk-through images from a single reference image. By navigating a 3D scene model constructed from the image, TIP provides convincing 3D effects. This paper presents a comprehensive scheme for creating walk-through images from a video sequence by generalizing the idea of TIP. To address various problems in dealing with a video sequence rather than a single image, the proposed scheme is designed to have the following features: First, it incorporates a new modeling scheme based on a vanishing circle identified in the video, assuming that the input video contains a negligible amount of motion parallax effects and that dynamic objects move on a flat terrain. Second, we propose a novel scheme for automatic background detection from the video, based on 4-parameter motion model and statistical background color estimation. Third, to assist the extraction of static or dynamic foreground objects from video, we devised a semiautomatic boundary-segmentation scheme based on enhanced lane (Kang & Shin, 2002, Grophicol Models, 64(5), 282-303). The purpose of this work is to let users experience the feel of navigating into a video sequence with their own interpretation and imagination about a given scene. The proposed scheme covers various types of video films of dynamic scenes, such as sports coverage, cartoon animation, and movie films, in which objects are continuously changing their shapes and locations. It can also be used to produce a variety of synthetic video sequences by importing and merging dynamic foreign objects with the original video
Numerical analysis of dynamic T stress of moving interfacial crack
No full textA method to extract dynamic T stress term of moving interfacial crack is proposed. Anisotropic bimaterial which has subsonic crack propagation is considered, and interaction energy method is applied. Stress fields by the constant T stress and stress fields by the point force moving with the crack are obtained by using the series expansion method and Stroh formalism. J based interaction energy (P) between the constant T stress and the point force is calculated by Yeh formulation and the relation between interaction energy and T stress is obtained. Energy release rate and T stress of a moving interfacial crack are calculated numerically. Elastodynamic finite element code is developed to investigate fracture parameters for the propagating crack. Four nodes linear elastodynamic element is used and Newmark formulae are applied to integrate displacement and velocity. Node release method is adapted to simulate crack propagation along the interface. The energy release rate is calculated in the area moving with crack. T stress term is calculated from the interaction energy with a stress field formed by the moving point force. Five examples are solved to show the validity and time history of energy release rate and T stress. The energy release rate calculated from numerical analysis agrees well with an analytic solution and experimental results. The T stress of homogeneous specimen under the steady state condition shows a slightly different value compared with the stationary result. It is observed that the T stress of polymethyl methacrylate-steel specimen shows continuous change and the T stress of aluminum-polymethyl methacrylate specimen shows discontinuous jump when the initial crack initiates. From the result of the variation of T stress, the effect of T stress on the stability of crack propagation is observed
Smart Shin Guard
No full textFatigue assessment is a highly subjective yet important marker for high-performance athletes as they strive to maintain fitness and avoid injuries during the season. Fatigue and overexertion is the leading cause of muscular injury in soccer players, primarily in the lower leg. This paper presents a smart shin-guard that can measure the bioimpedance of the calf muscle in a fully portable and wearable system. This marker can be linked to fatigue and fitness levels of the individual, allowing for both short and long-term tracking of player fitness levels.Undergraduat
Human CD8+ T-Cell Populations That Express Natural Killer Receptors
No full textCD8+ T cells are activated by TCRs that recognize specific cognate Ags, while NK-cell activation is regulated by a balance between signals from germline-encoded activating and inhibitory NK receptors. Through these different processes of Ag recognition, CD8+ T cells and NK cells play distinct roles as adaptive and innate immune cells, respectively. However, some human CD8+ T cells have been found to express activating or inhibitory NK receptors. CD8+ T-cell populations expressing NK receptors straddle the innate-adaptive boundary with their innate-like features. Recent breakthrough technical advances in multi-omics analysis have enabled elucidation of the unique immunologic characteristics of these populations. However, studies have not yet fully clarified the heterogeneity and immunological characteristics of each CD8+ T-cell population expressing NK receptors. Here we aimed to review the current knowledge of various CD8+ T-cell populations expressing NK receptors, and to pave the way for delineating the landscape and identifying the various roles of these T-cell populations. © 2023, Korean Association of Immunologists. All rights reserved.11Nsciescopuskc
Foxp3(+)CD4(+)CD25(+) T cells control virus-specific memory T cells in chimpanzees that recovered from hepatitis C
No full textHepatitis C virus (HCV) poses a global health problem because it readily establishes persistent infection and a vaccine is not available. CD4(+)CD25(+) T cells have been implicated in HCV persistence because their frequency is increased in the blood of HCV-infected patients and their in vitro depletion results in increased IFN-gamma production by HCV-specific T cells. Studying a well-characterized cohort of 16 chimpanzees, the sole animal model for HCV infection, we here demonstrate that the frequency of Foxp3(+)CD4(+)CD25(+) regulatory T cells (T-Regs) and the extent of suppression was as high in spontaneously HCV-recovered chimpanzees as in persistently HCV-Infected chimpanzees. Foxp3(+)CD4(+)CD25(+) T-Regs, suppressed IFN-gamma production, expansion, and activation-induced cell death of HCV-specific T cells after recovery from HCV infection and in persistent HCV infection. Thus, T-Reg cells control HCV-specific T cells not only in persistent infection but also after recovery, where they may regulate memory T-cell responses by controlling their activation and preventing apoptosis. However, Foxp3+CD4+CD25+ TReg cells of both HCV-recovered and HCV-infected chimpanzees differed from Foxp3(+)CD4(+)CD25(+)TReg cells of HCV-naive chimpanzees in increased IL-2 responsiveness and lower T-cell receptor excision circle content, implying a history of in vivo proliferation. This result suggests that HCV infection alters the population of Foxp3+CD4+CD25+ TReg cells
T-type Ca2+ channels in normal and abnormal brain functions.
No full textLow-voltage-
activated T-type Ca2 channels are widely expressed in various types of neurons.
Once deinactivated by hyperpolarization, T-type channels are ready to be activated by a
small depolarization near the resting membrane potential and, therefore, are optimal
for regulating the excitability and electroresponsiveness of neurons under physiological conditions
near resting states. Ca2 influx through T-type channels engenders low-threshold Ca2 spikes,
which in turn trigger a burst of action potentials. Low-threshold burst firing has been implicated in
the synchronization of the thalamocortical circuit during sleep and in absence seizures. It also has
been suggested that T-type channels play an important role in pain signal transmission, based on
their abundant expression in pain-processing pathways in peripheral and central neurons. In this
review, we will describe studies on the role of T-type Ca2 channels in the physiological as well as
pathological generation of brain rhythms in sleep, absence epilepsy, and pain signal transmission.
Recent advances in studies of T-type channels in the control of cognition will also be briefly
discussed.148521sciescopu
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