287 research outputs found
The Alteration of Intrinsic Excitability and Synaptic Transmission in Lumbar Spinal Motor Neurons and Interneurons of Severe Spinal Muscular Atrophy Mice
Spinal muscular atrophy (SMA) is the leading genetic cause of death in infants. Studies with mouse models have demonstrated increased excitability and loss of afferent proprioceptive synapses on motor neurons (MNs). To further understand functional changes in the motor neural network occurring in SMA, we studied the intrinsic excitability and synaptic transmission of both MNs and interneurons (INs) from ventral horn in the lumbar spinal cord in the survival motor neuron (SMN)Δ7 mouse model. We found significant differences in the membrane properties of MNs in SMA mice compared to littermate controls, including hyperpolarized resting membrane potential, increased input resistance and decreased membrane capacitance. Action potential (AP) properties in MNs from SMA mice were also different from controls, including decreased rheobase current, increased amplitude and an increased afterdepolarization (ADP) potential. The relationship between AP firing frequency and injected current was reduced in MNs, as was the threshold current, while the percentage of MNs showing long-lasting potentiation (LLP) in the intrinsic excitability was higher in SMA mice. INs showed a high rate of spontaneous firing, and those from SMA mice fired at higher frequency. INs from SMA mice showed little difference in their input-output relationship, threshold current, and plasticity in intrinsic excitability. The changes observed in both passive membrane and AP properties suggest greater overall excitability in both MNs and INs in SMA mice, with MNs showing more differences. There were also changes of synaptic currents in SMA mice. The average charge transfer per post-synaptic current of spontaneous excitatory and inhibitory synaptic currents (sEPSCs/sIPSCs) were lower in SMA MNs, while in INs sIPSC frequency was higher. Strikingly in light of the known loss of excitatory synapses on MNs, there was no difference in sEPSC frequency in MNs from SMA mice compared to controls. For miniature synaptic currents, mEPSC frequency was higher in SMA MNs, while for SMA INs, both mEPSC and mIPSC frequencies were higher. In SMA-affected mice we observed alterations of intrinsic and synaptic properties in both MNs and INs in the spinal motor network that may contribute to the pathophysiology, or alternatively, may be a compensatory response to preserve network function
The modal analysis of disc resonator gyroscope using isogeometric analysis
This paper presents a free vibration analysis of the disc resonator gyroscope (DRG) based on the Isogeometric Analysis (IGA). The non-uniform rational B-splines (NURBS) basis functions are employed to represent both the exact geometry of DRG and displacement fields. It provides a unified process between the geometric design and analysis which significantly reduces the design cycle by eliminating the re-meshing process. Moreover, the modeling process of IGA and the numerical example of three-circle cascaded model with four different refinement schemes are presented and the computational accuracy and efficiency of the present numerical method are verified by comparing with the standard finite method (ABAQUS)
La Influencia de la Motivación Laboral en los Trabajadores del Comisariato PolicÃa Nacional del departamento de Matagalpa. Año 2013
En la presente investigación se estudió la influencia de la motivación laboral en los trabajadores del Comisariato PolicÃa Nacional del departamento de Matagalpa, durante el Año 2013, esto con el propósito de analizar la influencia de la motivación laboral de los trabajadores.
Dicho estudio es de gran importancia, porque a través de éste, permitirá al lector interesado en el tema, tomar en consideración las técnicas y factores que influyen en una motivación aceptable para los empleados de las instituciones presentes en el departamento de Matagalpa y principalmente a los trabajadores del Comisariato.
Los resultados obtenidos mostraron que el comisariato cuenta con ciertos elementos de la motivación aplicado a sus empleados como: el dinero, calidad de vida laboral, enriquecimiento del puesto y participación en ciertas ocasiones, pero es necesario aun mejorarlos debido a que no existe una constante aplicación de un sistema de motivación adecuado que abarque a todos los empleados de la organización, generándoles satisfacción a todos.
Como parte de la influencia de la motivación laboral en los trabajadores estos elementos son considerados de importancia y necesarias de su aplicación, con esto se podrÃa mejorar, a través de una buena estrategia se llegarÃa a satisfacer las necesidades y se obtendrÃa un personal motivado.
Es por ello que es necesario que la dirección administrativa del comisariato establezca mejores técnicas motivacionales y factores que lo conlleven a tener personal satisfecho con alto nivel de la motivación que permitirá la ejecución de actividades con eficiencia y eficaci
Effect of Toll-Like Receptor 4 on Synovial Injury of Temporomandibular Joint in Rats Caused by Occlusal Interference
Superconductivity in a new layered cobalt oxychalcogenide NaCoSeO with a 3 triangular lattice
Unconventional superconductivity in bulk materials under ambient pressure is
extremely rare among the 3 transition-metal compounds outside the layered
cuprates and iron-based family. It is predominantly linked to highly
anisotropic electronic properties and quasi-two-dimensional (2D) Fermi
surfaces. To date, the only known example of the Co-based exotic superconductor
was the hydrated layered cobaltate, NaCoO yHO, and its
superconductivity is realized in the vicinity of a spin-1/2 Mott state.
However, the nature of the superconductivity in these materials is still an
active subject of debate, and therefore, finding new class of superconductors
will help unravel the mysteries of their unconventional superconductivity. Here
we report the discovery of unconventional superconductivity at 6.3 K in
our newly synthesized layered compound NaCoSeO, in
which the edge-shared CoSe octahedra form [CoSe] layers with a
perfect triangular lattice of Co ions. It is the first 3 transition-metal
oxychalcogenide superconductor with distinct structural and chemical
characteristics. Despite its relatively low , material exhibits
extremely high superconducting upper critical fields, , which
far exceeds the Pauli paramagnetic limit by a factor of 3 - 4. First-principles
calculations show that NaCoSeO is a rare example of
negative charge transfer superconductor. This new cobalt oxychalcogenide with a
geometrical frustration among Co spins, shows great potential as a highly
appealing candidate for the realization of high- and/or unconventional
superconductivity beyond the well-established Cu- and Fe-based superconductor
families, and opened a new field in physics and chemistry of low-dimensional
superconductors
Separating and characterizing functional alkane degraders from crude-oil-contaminated sites via magnetic nanoparticle-mediated isolation
Uncultivable microorganisms account for over 99% of all species on the planet, but their functions are yet not well characterized. Though many cultivable degraders for n-alkanes have been intensively investigated, the roles of functional n-alkane degraders remain hidden in the natural environment. This study introduces the novel magnetic nanoparticle-mediated isolation (MMI) technology in Nigerian soils and successfully separates functional microbes belonging to the families Oxalobacteraceae and Moraxellaceae, which were dominant and responsible for alkane metabolism in situ. The alkR-type n-alkane monooxygenase genes, instead of alkA- or alkP-type, were the key functional genes involved in the n-alkane degradation process. Further physiological investigation via a BIOLOG PM plate revealed some carbon (Tween 20, Tween 40 and Tween 80) and nitrogen (tyramine, L-glutamine and D-aspartic acid) sources promoting microbial respiration and n-alkane degradation. With further addition of promoter carbon or nitrogen sources, the separated functional alkane degraders significantly improved n-alkane biodegradation rates. This suggests that MMI is a promising technology for separating functional microbes from complex microbiota, with deeper insight into their ecological functions and influencing factors. The technique also broadens the application of the BIOLOG PM plate for physiological research on functional yet uncultivable microorganisms
Modelling and analysis of influenza A (H1N1) on networks
Network modelling is a useful tool for studying the transmission of H1N1 in China, capturing the main features of the spread of H1N1. The paper calculates the basic reproduction number and studies the effects of various immunization schemes. The final size relation is derived for the network epidemic model. While a uniform, mass-immunization strategy helps control the prevalence, a targeted immunization strategy focusing on specific groups with given connectivity may better control an epidemic
A comprehensive genome variation map of melon identifies multiple domestication events and loci influencing agronomic traits
Melon is an economically important fruit crop that has been cultivated for thousands of years; however, the genetic basis and
history of its domestication still remain largely unknown. Here we report a comprehensive map of the genomic variation in
melon derived from the resequencing of 1,175 accessions, which represent the global diversity of the species. Our results suggest that three independent domestication events occurred in melon, two in India and one in Africa. We detected two independent sets of domestication sweeps, resulting in diverse characteristics of the two subspecies melo and agrestis during melon
breeding. Genome-wide association studies for 16 agronomic traits identified 208 loci significantly associated with fruit mass,
quality and morphological characters. This study sheds light on the domestication history of melon and provides a valuable
resource for genomics-assisted breeding of this important crop.info:eu-repo/semantics/acceptedVersio
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