Quantitative analysis of the three main genera in effective microorganisms using qPCR

Effective microorganism (EM) cultures have been applied in many research fields such as agriculture, environment and bioremediation. EM is a mixed culture of microorganisms including predominant populations of lactic acid bacteria and yeasts with smaller numbers of photosynthetic bacteria, actinomycetes and other types of microorganisms. Quantitative analysis of EM is requisite for the applications of EM, as its efficiency varies depending on the composition of its main genera of EM. In this study, Rhodobacter sphaeroides, Rhodopseudomonas palustris, Lactobacillus plantarum, and Saccharomyces cerevisiae, the main genera of EM were quantified by quantitative real time polymerase chain reaction, (qRT-PCR). By using selected specific primers, photosynthetic bacteria, lactic acid bacteria and yeast were quantified with high sensitivity and specificity. The ability of viable cell count by qRT-PCR was compared with agar plate cell count, showing linear relationship. Thus, PCR based quantification system is a rapid and highly specific and sensitive tool for the quantification of EM.     

Differential Expressions of G0/G1 Switch Gene 2 and Comparative Gene Identification-58 are Associated with Fat Content in Bovine Muscle

Regulation of lipolysis in muscle is a potential mechanism affecting marbling in beef carcasses and fat accumulation in muscles of humans, which is a known risk factor for type 2 diabetes. Adipose triglyceride lipase-mediated lipolysis is inhibited by G0/G1 switch gene 2 (G0S2) and co-activated by comparative gene identification-58 (CGI-58). In this study, bovine G0S2 and CGI-58 were sequenced, and expressions of these genes were compared among various tissues and in muscles between bulls and steers with different degrees of marbling. The protein coding sequences of bovine G0S2 and CGI-58 revealed breed-specific SNPs, causing two amino acid variations for each protein. Bovine CGI-58 mRNA showed two isoforms from alternative splicing. The G0S2 gene was preferentially expressed in fat and, to a lesser degree, in the liver; whereas, CGI-58 was highly expressed in the muscle and fat (P < 0.05), suggesting their association with lipid metabolism in those tissues. The longissimus dorsi muscle (LM) of steers showed higher FABP4, G0S2 and CGI-58 mRNA expression levels than the LM of bulls, implying the roles of those genes more in marbling of steers than in that of bulls. The G0S2 expression was markedly higher in the intramuscular fat (IMF) (P < 0.001); whereas, the CGI-58 expression was significantly higher in the pure muscle portion of the LM of steers (P < 0.01), suggesting that G0S2 and CGI-58 may regulate IMF and intramyocellular triglycerides, respectively. Taken together, our data suggest that G0S2 and CGI-58 are associated with fat content in bovine species.     

Effect of an Orifice on Collection Efficiency and Wall Loss of a Slit Virtual Impactor

The effect of an orifice on the collection efficiency and wall loss of a slit virtual impactor was investigated both numerically and experimentally. The ratios of the collection nozzle width (W_c ), distance between acceleration nozzle and collection nozzle (S), length of acceleration nozzle (T), inlet width (D), and nozzle span (l) to the acceleration nozzle width (W_a ) were fixed at W_c /W_a = 1.4, S/W_a = 1.5, T/W_a = 1.1, D/W_a = 6, and l/W_a = 10, respectively. The minor-to-total flow ratio was set to 0.1 in laminar flow regime. The collection efficiency and wall loss of the slit virtual impactor were found to be characterized by the square root of the Stokes number. For the slit virtual impactor without an orifice, the square root of the Stokes number corresponding to the cut-off diameter was determined to be (Stk₅₀)^1/2 = 0.77 and the maximum wall loss at the collection nozzle reached 30% or 40%. When an orifice having the same width as the acceleration nozzle was placed upstream of the acceleration nozzle at a distance of 20W_a , the value of (Stk₅₀)^1/2 decreased to 0.68 and the wall loss at the collection nozzle decreased below 5%.

Copyright 2014 American Association for Aerosol Research     

Predictive position and force control for shape memory alloy cylinders

In this paper, a linear lightweight electric cylinder constructed using shape memory alloy (SMA) is proposed. Spring SMA is used as the actuator to control the position and force of the cylinder rod. The model predictive control algorithm is investigated to compensate SMA hysteresis phenomenon and control the cylinder. In the predictive algorithm, the future output of the cylinder is computed based on the cylinder model, and the control signal is computed to minimize the error and power criterion. The cylinder model parameters are estimated by an online identification algorithm. Experimental results show that the SMA cylinder is able to precisely control position and force by using the predictive control strategy though the hysteresis effect existing in the actuator. The performance of the proposed controller is compared with that of a conventional PID controller.     

沿岸及内陆风机塔筒的防腐涂料与涂装体系

针对不同腐蚀环境,介绍了内陆和近海沿岸地区风机塔筒的防腐涂料与涂装体系。讨论了风机涂装体系中的面漆和水性涂料体系设计方案。     

Mn3O4 nanoparticles embedded into graphene nanosheets: Preparation, characterization, and electrochemical properties for supercapacitors

Mn₃O₄/graphene nanocomposites were synthesized by mixing graphene suspension in ethylene glycol with MnO₂ organosol, followed by subsequent ultrasonication processing and heat treatment. The as-prepared product consists of nanosized Mn₃O₄ particles homogeneously distributed on graphene nanosheets, which has been confirmed by field emission scanning electron microscopy and transmission electron microscopy analysis. Atomic force microscope analysis further identified the distribution of dense Mn₃O₄ nanoparticles on graphene nanosheets. When used as electrode materials in supercapacitors, Mn₃O₄/graphene nanocomposites exhibited a high specific capacitance of 175 F g⁻¹ in 1 M Na₂SO₄ electrolyte and 256 F g⁻¹ in 6 M KOH electrolyte, respectively. The enhanced supercapacitance of Mn₃O₄/graphene nanocomposites could be ascribed to both electrochemical contributions of Mn₃O₄ nanoparticles, functional groups attached to graphene nanosheets, and significantly increased specific surface area.     

Preparation and properties of bio‐nanoreinforced composites from biodegradable polymer matrix and cellulose whiskers

Crystalline cellulose was extracted from one of the cheapest source; grass by alkali, acid, and mechanical treatments. To evaluate the reinforcing effect of this filler, biodegradable polymer matrix, polylactic acid (PLA) was used and samples were prepared at different concentrations. The modified whiskers were also used as filler to examine the effect on mechanical properties. Crystallinity, thermal behavior, surface morphology and functional group variation was monitored through, XRD, TGA, SEM, and FTIR respectively. The properties were largely depending on the concentration of filler whereas; modification of hydroxyl groups did not exhibit remarkable change in mechanical properties. Thermal resistance was decreased in comparison of neat matrix and reduction in crystallinity was also observed for composites, regardless of filler nature. It was thought that the hydrophilicity of cellulose could be altered by modifying its hydroxyl groups, thereby promoting dispersion. However, the possibility of phase separation was increased, and the thermal stability of the composites gradually decreased with increasing filler load in the matrix. In the examined systems, it was observed that improvement of reinforcing capacity may not only depend on the chemical compatibility between matrixes but also some compositional and physical parameters may be responsible for variation in properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Ultrasound assisted batch-processing of EVA-organoclay nanocomposites

The aim of this study was to investigate the effect of ultrasound on the properties of a poly[ethylene-co-(vinyl acetate)] (EVA)-organoclay nanocomposite. By using a torque rheometer, in-situ rheological behaviors of various EVA resins with varying VA content were examined. It was found that the effect of ultrasound was most significant for EVA 31 (31 wt% VA). EVA31/organoclay nanocomposites were prepared in batch mixer with and without irradiation of ultrasound. The characterization of the nanocomposite was performed using XRD, TEM, rheometry, and universal testing machine. XRD and TEM results revealed that the produced EVA31/organoclay nanocomposite with ultrasonic irradiation possessed intercalated structure. Rheometry result indicated that EVA31/organoclay nanocomposite processed with ultrasound had a highly disordered or delaminated structure. A considerable increase in stiffness and Young’s modulus for the sonicated nanocomposite compared to those for unsonicated one was obtained. This study demonstrated the possibility of producing EVA-organoclay nanocomposites with enhanced dispersion of nanoclays using ultrasound assisted processing.     

Recent Advances in the Application of Natural Fiber Based Composites

Natural fiber reinforced polymer composites are lightweight, economical and available in a variety of forms. They have low densities, comparable material properties, high molding flexibility and are environmentally friendly, making them a conceivable alternative to traditional fillers like mica, calcium carbonate and glass. By modifying either the resin system or the natural fiber, biocomposites can be designed for different applications ranging from products of commodity to aerospace, examples including electroactive papers, fuel cell membranes, controlled drug release mechanisms and biosensors. This review aims to analyze the advancement in the application of cellulose based materials in different sectors with a discussion of fundamental research in these areas.

     

Frictionally excited thermo-elastoplastic instability

A transient finite element simulation is used to solve the two-dimensional contact problem involving thermo-elastoplastic instability (TEPI) in frictional sliding system. The existence of plastic deformation below the critical speed for thermoelastic instability is independent of the size of initial perturbation. For the simulation of the first/second partial contact, the amount of initial perturbation affects only the time interval of the first partial contact and the second partial contact is reached earlier, regardless of the initial perturbation. In addition, it shows that the locations of hot spots after cooling are changed.