5,232 research outputs found
Clustering of nicotinic acetylcholine receptors: from the neuromuscular junction to interneuronal synapses
Fast and accurate synaptic transmission requires high-density accumulation of neurotransmitter receptors in the postsynaptic membrane. During development of the neuromuscular junction, clustering of acetylcholine receptors (AChR) is one of the first signs of postsynaptic specialization and is induced by nerve-released agrin. Recent studies have revealed that different mechanisms regulate assembly vs stabilization of AChR clusters and of the postsynaptic apparatus. MuSK, a receptor tyrosine kinase and component of the agrin receptor, and rapsyn, an AChR-associated anchoring protein, play crucial roles in the postsynaptic assembly. Once formed, AChR clusters and the postsynaptic membrane are stabilized by components of the dystrophin/utrophin glycoprotein complex, some of which also direct aspects of synaptic maturation such as formation of postjunctional folds. Nicotinic receptors are also expressed across the peripheral and central nervous system (PNS/CNS). These receptors are localized not only at the pre- but also at the postsynaptic sites where they carry out major synaptic transmission. In neurons, they are found as clusters at synaptic or extrasynaptic sites, suggesting that different mechanisms might underlie this specific localization of nicotinic receptors. This review summarizes the current knowledge about formation and stabilization of the postsynaptic apparatus at the neuromuscular junction and extends this to explore the synaptic structures of interneuronal cholinergic synapse
Endogenous circatidal rhythm in the Manila clam Ruditapes philippinarum (Bivalvia: Veneridae)
Manila clams, Ruditapes philippinarum, removed from their natural environment and maintained for 9 weeks in continuously immersed conditions exhibited a clear endogenous circatidal rhythm in oxygen consumption. The clams exhibited a semidiurnal rhythmicity in oxygen consumption after showing a diurnal pattern in the first few days (5 to 7ād) of the experiment. The results of the present study indicate that activity rhythms of clams are controlled not only by exogenous factors, but also by an endogenous circatidal periodicity
PRELIMINARY EVALUATION OF A PRECISE STARTING SENSOR FOR SHORT DISTANCE ATHLETIC SPORTS BELOW 400 m
The importance of starting a race in short distance athletic sports below 400 m was rarely considered to the extent that it should be. The main research theme in this field has mainly been the relationship between the starting signal and the response speed of leg muscles. The records in short distance athletic sports have been improved through training athletes to increase their response speed. However, the improvements in records have also been due to the starting time speed; thus, there is another way to improve times, that is, through the starting speed. The starting speed related to the kicking force against the starting blocks at the start of a race. The objectives of this research were to present a method for analyzing forces acting upon a starting block at the start of a race and to optimize the starting conditions for each athlete. To achieve these objectives, a starting block with Wheatstone bridge type strain gauges which could measure, in normal and horizontal directions, the repulsive forces acting on the starting blocks at a starting point in real-time, was developed. The use of this block was expected to correct the posture of each athlete and record the sports dynamics data for each athlete
Construction of the Hill48 and Yld89 for Auto-body Steel Sheets considering the Strain Rate
This paper deals with the anisotropic material properties and the initial yield locus considering the strain rate. Uni-axial tensile tests are performed with variation of the strain rate in order to obtain flow stress curves and the tensile properties. The R-values have been measured with a high speed camera by analyzing the deformation history during the tensile test. Anisotropy of auto-body steel sheets have been described by using Hill48 and Yld89 (Barlat89) yield functions according to the strain rate ranged from 0.001/sec to 100/sec. Hill48 and Yld89 yield loci of auto-body steel sheets at various strain rates have been constructed in order to visualize the initial yield state. The performance of two yield criteria is evaluated by comparing yield loci constructed in the principal stress plane. The initial yield locus becomes different from the static one when the strain rate is considered to describe the anisotropy of the steel sheets
Electronic density of states derived from thermodynamic critical field curves for underdoped La-Sr-Cu-O
Thermodynamic critical field curves have been measured for
over the full range of carrier concentrations
where superconductivity occurs in order to determine changes in the normal
state density of states with carrier concentration. There is a substantial
window in the plane where the measurements are possible because the
samples are both thermodynamically reversible and the temperature is low enough
that vortex fluctuations are not important. In this window, the data fit
Hao-Clem rather well, so this model is used to determine and
for each temperature and carrier concentration. Using N(0) and the ratio of the
energy gap to transition temperature, , as fitting
parameters, the curves give over the
whole range of . Values of N(0) remain rather constant in the optimum-doped
and overdoped regime, but drops quickly toward zero in the underdoped regime.
Measuring Childrenās Perceptions of Their Motherās Depression: The Childrenās Perceptions of Othersā Depression Scale ā Mother Version
Several theoretical perspectives suggest that knowledge of childrenās perceptions of and beliefs about their parentsā depression may be critical for understanding its impact on children. This paper describes the development and preliminary evidence for the psychometric properties of a new measure, the Childrenās Perceptions of Othersā Depression ā Mother Version (CPOD-MV), which assesses theoretically- and empirically driven constructs related to childrenās understanding and beliefs about their mothersā depression. These constructs include childrenās perceptions of the severity, chronicity, and impairing nature of their mothersā depression; self-blame for their motherās depression; and beliefs about their abilities to deal with their mother\u27s depression by personally coping or alleviating the motherās depression. The CPOD-MV underwent two stages of development. First: (1) a review of the literature to identify the key constructs; (2) focus groups to help generate items; and (3) cliniciansā ratings on the relevance and comprehensibility of the drafted items. Second was a study of the measureās psychometric properties. The literature review, focus groups, and item reduction techniques yielded a 21-item measure. Reliability, factor structure, and discriminant, convergent and concurrent validity were tested in a sample of 91 10- to17- year-old children whose mothers had been treated for depression. The scale had good internal consistency, factor structure suggestive of a single construct, discriminant, concurrent, convergent, and incremental validity, suggesting the importance of measuring childrenās perceptions of their mothersā depression, beyond knowledge of mothersā depression symptom level, when explaining which children have the greatest risk for emotional and behavioral problems among children of depressed mothers. These findings support continued development and beginning clinical applications of the scale
Assessing the Geomorphic Evolution and Hydrographic Changes Induced by Winter Storms along the Louisiana Coast
The influence that cold front passages have on Louisiana coastal environments, including land loss and land building processes, has been the primary topic of this multidisciplinary research. This research has combined meteorological, remote sensing, and coastal expertise from the University of Wisconsin (UW) and Louisiana State University (LSU). Analyzed data sets include remotely sensed radiometric data (AVHRR on NOAA-12,13,14, Multispectral Atmospheric Mapping Sensor (MAMS) and MODIS Airborne Simulator (MAS) on NASA ER-2), U.S. Army Corps of Engineers (USACE) water level data, water quality data from the Coastal Studies Institute (CSI) at LSU, USACE river discharge data, National Weather Service (NWS) and CSI wind in sitzi measurements, geomorphic measurements from aerial photography (NASA ER-2 and Learjet), and CSI ground based sediment burial pipes (for monitoring topographic change along the Louisiana coast) and sediment cores. The work reported here-in is a continuation of an initial investigation into coastal Louisiana landform modification by cold front systems. That initial effort demonstrated the importance of cold front winds in the Atchafalaya Bay sediment plume distribution (Moeller et al.), documented the sediment transport and deposition process of the western Louisiana coast (Huh et al.) and developed tools (e.g. water types identification, suspended solids estimation) from multispectral radiometric data for application to the current study. This study has extended that work, developing a Geomorphic Impact Index (GI(sup 2)) for relating atmospheric forcing to coastal response and new tools to measure water motion and sediment transport
Effects of 3D-printed polycaprolactone/ļæ½ļæ½-tricalcium phosphate membranes on guided bone regeneration
This study was conducted to compare 3D-printed polycaprolactone (PCL) and polycaprolactone/ļæ½ļæ½-tricalcium phosphate (PCL/ļæ½ļæ½-TCP) membranes with a conventional commercial collagen membrane in terms of their abilities to facilitate guided bone regeneration (GBR). Fabricated membranes were tested for dry and wet mechanical properties. Fibroblasts and preosteoblasts were seeded into the membranes and rates and patterns of proliferation were analyzed using a kit-8 assay and by scanning electron microscopy. Osteogenic differentiation was verified by alizarin red S and alkaline phosphatase (ALP) staining. An in vivo experiment was performed using an alveolar bone defect beagle model, in which defects in three dogs were covered with different membranes. CT and histological analyses at eight weeks after surgery revealed that 3D-printed PCL/ļæ½ļæ½-TCP membranes were more effective than 3D-printed PCL, and substantially better than conventional collagen membranes in terms of biocompatibility and bone regeneration and, thus, at facilitating GBR. ? 2017 by the authors. Licensee MDPI, Basel, Switzerland.118Ysciescopu
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