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1.
During the early development of skeletal muscle, cardiac isotypes of several contractile proteins are known to be transiently expressed. We report here that skeletal muscle developing in vivo, as well as primary cultures derived from skeletal muscle, express mRNA encoding the cardiac dihydropyridine-sensitive calcium channel. The mRNA is detectable at high concentration at the earliest stage tested in vivo and diminishes rapidly in concentration as myofibers mature. The concentration of the cardiac calcium channel mRNA also diminishes during the in vivo development of skeletal muscle in a genetically paralyzed mouse (mdg), indicating that muscle contractile activity is not necessary for the down-regulation. In contrast, mRNA for the skeletal muscle-specific calcium channel accumulates gradually in developing skeletal muscle. A similar temporal pattern of expression is also seen in primary cultures of skeletal myotubes. These results raise the question of whether the cardiac calcium channel may be functionally important during the early development of skeletal myofibers. 相似文献
2.
Multiphase reactors involving gas, liquid, and solid phases have several important applications in the chemical industry, particularly in catalytic processes. Some of the well-known examples are: hydrogenation and oxidation of organic compounds, hydro-processing coal-derived and petroleum oils, Fischer-Tropsch synthesis, and methanation reactions. Due to the presence of three phases, the problem of reactor design is often important to achieve effective mass and heat transfer as well as a mixing pattern favorable to the particular process. The reactors are mainly of two types: (a) solid catalyst is suspended either by mechanical agitation or gas-induced agitation and (b) solid catalyst is in a fixed bed with concurrent or countercurrent feed of gas and liquid re-actants. The reactor types conventionally used in industry are: (a) mechanically agitated or bubble column slurry reactors and (b) trickle-bed or packed-bed bubble reactor. The various design and modeling aspects of these reactors have been reviewed by Satterfield [1], Chaudhari and Ramachandran [2], Shah [3,4], Ramachandran and Chaudhari [5], Shah et al. [6], and Herskowitz and Smith [7]. In several industrial processes these reactor designs are modified to achieve a certain specific objective, such as better heat or mass transfer, higher catalyst efficiency, better reactor performance and selectivity, etc. Similarly, specially designed reactors are often used for laboratory kinetic studies or to understand a certain phenomenon. Thus, novel multiphase reactors are becoming important from both academic and industrial viewpoints. Some of the recently introduced novel gas-liquid-solid reactor types are: (a) loop recycle slurry reactors, (b) basket-type reactors, (c) ebullated-bed reactors, (d) internal or external recycle reactors, (e) multistage slurry or packed-bed reactors, (f) column reactors with sieve trays or multiple agitators, (g) gas-induced agitated reactors, and (h) horizontal-packed-bed reactors. are being used in several new commercial processes, and various design aspects, such as hydrodynamics and mass and heat transfer, have been the subject of investigations in the last few years. However, no attempt to review the scattered information on these novel gas-liquid-solid reactors has been made. Therefore, the main objective of this paper is to review important developments in novel gas-liquid-solid reactors. For each type of reactor, advantages, disadvantages, and applications are discussed. Further, the status of information on hydrodynamics and mass transfer parameters and scale-up considerations is reviewed. These novel reactor designs are being used in several new commercial processes, and various design aspects, such as hydrodynamics and mass and heat transfer, have been the subject of investigations in the last few years. However, no attempt to review the scattered information on these novel gas-liquid-solid reactors has been made. Therefore, the main objective of this paper is to review important developments in novel gas-liquid-solid reactors. For each type of reactor, advantages, disadvantages, and applications are discussed. Further, the status of information on hydrodynamics and mass transfer parameters and scale-up considerations is reviewed. 相似文献
3.
Learning of (context-free) grammar rules that are based on alignment between texts of a given collection of sentences has attracted the attention of many researchers. We define and study the alignment profile and formulate fuzzy similarity of alignment profiles for a given collection of sentences. Using the fuzzy-similarity-based profile alignment, we give a methodology to formulate stochastic context-free grammar (CFG) rules. We introduce profile-alignment-based dynamic sentence similarity threshold to formulate the rules of stochastic CFG. The proposed methodology is tested using Child Language Data Exchange System (CHILDES) dataset of sentences. The benefits of our approach are experimentally demonstrated. Since our approach does not make use of any domain knowledge, it is expected to be useful in wide variety of applications requiring model construction. 相似文献
4.
Bi‐layered composites of polyaniline (PANI) and poly(o‐anisidine) (POA) were investigated for corrosion protection of low carbon steel (LCS). In this work, homopolymers and bi‐layers of PANI and POA were electropolymerized on LCS from an aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Corrosion tests were carried out in aqueous 3% NaCl solution for LCS coated with PANI, POA, bi‐layered POA/PANI (POA on top of the PANI) or PANI/POA (PANI on top of the POA) composites using open circuit potential (OCP) measurements, potentiodynamic polarization technique, and electrochemical impedance spectroscopy (EIS). The single layer of PANI and POA protected the LCS in 3% NaCl for 8 and 16 h, respectively. The bi‐layered composite coatings provide effective protection to LCS for a longer time than a single layered PANI or POA coating. However, the corrosion protection offered to LCS depends on the deposition order of polymer layers in the composite. The PANI/POA composite provides better protection to LCS against corrosion than POA/PANI coating. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
5.
A.K. Padap G.P. Chaudhari S.K. Nath V. Pancholi 《Materials Science and Engineering: A》2009,527(1-2):110-117
Grain refinement of bulk metals using severe plastic deformation (SPD) is a popular approach to improve both strength and toughness. In this paper, grain refinement of steel processed by warm multiaxial forging (MAF) and its mechanical behavior has been investigated. Coarse-grained, plain low carbon steel was deformed using MAF at 500 °C. Microstructural evolution is characterized using electron backscattered diffraction and mechanical behavior has been studied. Fraction of low angle grain boundaries (LAB) is observed to increase with strain up to total engineering strain of 1.3 thereafter it starts decreasing whereas, high angle grain boundaries showed just the opposite trend. It appears that initially grain subdivision takes place with imposition of strain thereby increasing the fraction of LAB. After a critical strain these LAB transforms into the high angle boundaries (HAB). The initial coarser grains of average 30 μm size subdivided into grains of the size finer than 0.5 μm. This has been confirmed by TEM micrographs. Improved tensile strengths and hardness values are obtained after warm MAF. 相似文献
6.
利用多模干涉效应和自由载流子等离子体色散效应设计和模拟了基于1.55μm波长的2×3 SiGe光开关.该光开关由两个单模输入端口、一个多模干涉区和三个单模输出端口构成.在多模干涉区,设有两个折射率调制区,可以利用来把从两个输入端口输入的光信号分别从三个输出端口输出.束传播法分析结果表明,该光开关的传输损耗小于1.43dB,串扰在-18~-32.8dB之间. 相似文献
7.
Prapti Chaudhari Satyendra Mishra 《Journal of Materials Science: Materials in Electronics》2018,29(1):117-123
The NiTiO3 nanoparticles with ilmenite phase were synthesized by the sol gel method and investigated for sensing of various volatile organic compounds. The resistive type sensing by NiTiO3 towards LPG was not reported earlier where the sensor showed fair response towards hydrogen sulfide gas, but the sensitivity towards LPG was very high. The response % for 150 ppm of LPG was approximately 3200% at room temperature. The high response towards LPG was due to the presence of some amount of rutile TiO2 in the composites. The response and recovery times of these sensors were very less (about 2 s) which could be attributed to the whiskers like structure of NiTiO3. 相似文献
8.
Theory of Constraints developed by E. M. Goldratt was initially applied to production scheduling and later to various areas such as Operations, Finance and Measures, Project Management, Marketing, Sales, Managing People, Strategy and Tactics. However, these applications were in engineering industries and products. The Strategic Thinking Processes of Theory of Constraints are designed to help combat an enormous problem faced by organizations--the tendency of organizations and their management to study, construct and implement solutions in isolation. In this case study, we applied the Theory of Constraints' Strategic Thinking Process in one of the leading integrated poultry businesses in India to identify and overcome the policy constraints in the business. After overcoming the policy constraints, overwhelming improvements in throughput and Inventories were observed. 相似文献
9.
5d-metal mononitrides and monoborides viz. X-N and X-B (X = La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg) are studied using density
functional method based B3LYP functional with LANL2DZ and SDD basis set. The lowest spin state, electron affinities, ionization
potentials and binding energies for mononitrides and monoborides are obtained. The electronic state and electronic configuration
of mononitrides and monoborides are discussed. Orbitals involved in bond formation are identified. The properties of mononitrides
and monoborides are compared. It is found that 5d-metal atoms form stronger bond with nitrogen atom than the boron atom. The range of binding energy, electron affinity and
ionization potential is wider for mononitrides than that for monoborides. The properties of 5d-metal mononitrides and 3d-metal mononitrides are also compared. The binding energies for the former are lower than those for the latter. 相似文献
10.
J. Chen N.S. Chaudhari 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2006,10(4):315-324
The formation of protein secondary structure especially the regions of β-sheets involves long-range interactions between amino acids. We propose a novel recurrent neural network architecture called
segmented-memory recurrent neural network (SMRNN) and present experimental results showing that SMRNN outperforms conventional
recurrent neural networks on long-term dependency problems. In order to capture long-term dependencies in protein sequences
for secondary structure prediction, we develop a predictor based on bidirectional segmented-memory recurrent neural network
(BSMRNN), which is a noncausal generalization of SMRNN. In comparison with the existing predictor based on bidirectional recurrent
neural network (BRNN), the BSMRNN predictor can improve prediction performance especially the recognition accuracy of β-sheets. 相似文献