Effect of high-concentrate diets on mRNA expression of genes related to muscle fiber type and metabolism of psoas major muscle in goats.

In the process of modern breeding, high-concentrate diets are widely used to meet the high energy nutritional requirements of animals but change the form of access to energy and nutrients and the way the organism metabolizes them. Goat psoas major (PM) muscle is a hybrid skeletal muscle whose characteristics are important for the motility and meat quality of goats. However, there are few studies on the effects of high-concentrate diets on the muscle type and metabolic characteristics of PM in goats. In this study, two treatment groups were set up: high concentrate group (HC) and control group (C). The expression of genes related to muscle type and metabolism of the PM was examined by quantitative PCR. The results showed that high concentrate promoted the conversion of PM fibers from intermediate to slow type at the mRNA level, improved the absorption, transport, and oxidation of fat by PM, and upregulated the expression of calpain system. These changes may be regulated by the involvement of differential expression of MSTN, Myf-5, and IGF-2. These results suggest that high concentrate may exert a positive effect on skeletal muscle function, metabolism, and meat quality in goats by affecting the expression of muscle type and metabolism-related genes.

Myostatin coordinating the proliferation and differentiation of adipose and skeletal muscle cells and energy metabolism balance based on gene chip technology / A miostatina na coordenação da proliferação e diferenciação de células musculares adiposas e esqueléticas e no equilíbrio do metabolismo energético com base na tecnologia de chips genéticos / Msrn, basado en la tecnología de chips genéticos, coordina la fertilización y el metabolismo de las células musculares grasas y óseas

ABSTRACT Myoblasts fuse into multinucleated muscle fibers to form and promote the growth of skeletal muscle. In order to analyze the role of myostatin (MSTN) in body fat, skeletal muscle cell proliferation and differentiation and energy metabolism, this study will use the antisense RNA technology of gene chip technology to study it. The results showed that the MSTN gene regulated the growth and proliferation of myoblasts and affected the development of skeletal muscle by affecting the expression of Cdc42, bnip2, p38 and other genes; knockout or overexpression of the MSTN gene would lead to a trend of fat-related genes from fat synthesis to fat decomposition; after the MSTN gene was knocked down, the expression levels of cpti-b, PPARG and other genes in the cells were corresponding after MSTN overexpression, the relative expression of the PPARG gene decreased. It is suggested that the knockout or overexpression of MSTN may affect lipid accumulation, and cpti-b and PPARG may directly regulate lipid level. It is hoped that this experiment can provide a reference for the study of MSTN effect on fat deposition.

RESUMO Os mioblastos se fundem eM fibras musculares multinucleadas para formar e promover o crescimento do músculo esquelético. A fim de analisar o papel da miostatina (MSTN) na gordura corporal, proliferação de células musculares esqueléticas e diferenciação e metabolismo energético, este estudo utilizará a tecnologia anti-RNA de chips genéticos para estudá-la. Os resultados mostraram que o gene MSTN regulava o crescimento e a proliferação de mioblastos e afetava o desenvolvimento do músculo esquelético, afetando a expressão de Cdc42, bnip2, p38 e outros genes; a eliminação ou sobrexpressão do gene MSTN conduziria a uma tendência de os genes adiposos sintetizarem a gordura até sua decomposição; após a eliminação do gene MSTN, os níveis de expressão de cpti-b, PPARG e outros genes nas células mostraram-se correspondentes após a sobrexpressão do gene MSTN, e a expressão relativa do gene PPARG diminuiu. Sugere-se que a eliminação ou sobrexpressão da MSTN possa afetar a acumulação de lipídeos, e o cpti-b e o PPARG podem regular diretamente o nível lipídico. Espera-se que esta experiência possa fornecer uma referência para o estudo do efeito da MSTN sobre a deposição de gordura.

RESUMEN Los mioblastos se funden en fibras musculares multinucleadas para formar y promover el crecimiento del músculo esquelético. A fin de analizar el papel de la miostatina (MSTN) en la grasa corporal, proliferación de células musculares esqueléticas y diferenciación y metabolismo energético, este estudio utilizará la tecnología anti-RNA de chips genéticos para estudiarla. Los resultados mostraron que el gen MSTN regulaba el crecimiento y la proliferación de mioblastos y afectaba el desarrollo del músculo esquelético, afectando la expresión de Cdc42, bnip2, p38 y otros genes; la eliminación o sobreexpresión del gen MSTN conduciría a una tendencia de que los genes adiposos sinteticen la grasa hasta su descomposición; después de la eliminación del gen MSTN, los niveles de expresión de cpti-b, PPARG y otros genes en las células se mostraron correspondientes después de la sobreexpresión del gen MSTN, y la expresión relativa del gen PPARG disminuyó. Se sugiere que la eliminación o sobreexpresión de la MSTN pueda afectar la acumulación de lipídos, y el cpti-b y el PPARG pueden regular directamente el nivel lipídico. Se espera que esta experiencia pueda proveer una referencia para el estudio del efecto de la MSTN sobre el depósito de grasa.

Design of triple-band metamaterial absorbers with refractive index sensitivity at infrared frequencies.

A triple-band perfect plasmonic metamaterial absorber based on a metal/insulator/metal (MIM) structure is designed. A new freedom through tuning the thicknesses of each ring structures is introduced to realize a quasi-three-dimensional perfect absorber at three extinction wavelengths by using the finite difference time domain method. The physical machine is explained by the time domain field analyses and the coupled mode theory. The characteristics of the absorber make our proposed strategy applicable for the design of more general multiband and broadband perfect absorbers. In addition, these perfect absorbing metamaterials are found to exhibit excellent performance in refractive index sensing.

Unique features of laterally aligned GeSi nanowires self-assembled on the vicinal Si (001) surface misoriented toward the [100] direction.

We demonstrate laterally aligned and catalyst-free GeSi nanowires (NWs) via self-assembly of Ge on miscut Si (001) substrates toward the [100] direction by an angle θ (θ < 11°). The NWs are bordered by (001) and (105) facets, which are thermodynamically stable. By tuning the miscut angle θ, the NW height can be easily modulated with a nearly constant width. The thickness of the wetting layer beneath the NWs also shows a peculiar behavior with a minimum at around 6°. An analytical model, considering the variation of both the surface energy and the strain energy of the epilayer on vicinal surfaces with the miscut angle and layer thickness, shows good overall agreement with the experimental results. It discloses that both the surface energy and stain energy of the epilayer on vicinal surfaces can be considerably affected in the same trend by the surface steps. Our results not only shed new light on the growth mechanism during heteroepitaxial growth, but also pave a prominent way to fabricate and meanwhile modulate laterally aligned and dislocation-free NWs.

Spin-resolved Purcell effect in a quantum dot microcavity system.

We demonstrate the spin selective coupling of the exciton state with cavity mode in a single quantum dot (QD)-micropillar cavity system. By tuning an external magnetic field, each spin polarized exciton state can be selectively coupled with the cavity mode due to the Zeeman effect. A significant enhancement of spontaneous emission rate of each spin state is achieved, giving rise to a tunable circular polarization degree from -90% to 93%. A four-level rate equation model is developed, and it agrees well with our experimental data. In addition, the coupling between photon mode and each exciton spin state is also achieved by varying temperature, demonstrating the full manipulation over the spin states in the QD-cavity system. Our results pave the way for the realization of future quantum light sources and the quantum information processing applications.

Localized-surface-plasmon enhanced emission from porous silicon by gold nanoparticles.

The porous silicon (PS) samples, decorated by Au nanoparticles (NPs) possessing localized-surface-plasmon (LSP) resonance, are prepared by the conventional anodization method. Photoluminescence (PL) is studied systematically, in particular, its dependence on the excitation power. It is found that undecorated PS samples exhibit a saturation behavior in PL intensity with increasing the pumping laser power, while the luminescence of Au-decorated PS hybrid samples have a purely linear dependence on the excitation power. In the linear response region of PS samples, addition of metal NPs layer moderately suppresses the emission while, in the saturation region, the net emission is enhanced by approximately up to 4-fold. Several possible mechanisms are discussed. We believe that the observed PL enhancement in saturation region is dominantly due to the resonant coupling between the LSP of Au NPs and the electronic excitation of PS, which inhibits the nonradiative Auger recombination process at high excitation power. These results indicate that the plasmon effect could be useful for designing even more efficient optoelectronic devices such as super bright light emitting devices and solar cells with high efficiencies. Despite many challenges, Au NPs can potentially be applied to introduce LSP resonance for the future silicon-based optoelectronics or photonics.

Direct observation of whispering gallery mode polaritons and their dispersion in a ZnO tapered microcavity.

We report direct observation of the strong exciton-photon coupling in a ZnO tapered whispering gallery (WG) microcavity at room temperature. By scanning excitations along the tapered arm of the ZnO tetrapod using a micro-photoluminescence spectrometer with different polarizations, we observed a transition from the pure WG optical modes in the weak interaction regime to the excitonic polariton in the strong coupling regime. The experimental observations are well described by using the plane wave model including the excitonic polariton dispersion relation. This provides a direct mapping of the polariton dispersion, and thus a comprehensive picture for coupling of different excitons with differently polarized WG modes.