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Feminization-1 homolog b (Fem1b) is one of the genes essential for male development and play central roles in sex determination of Caenorhabditis elegans. In this study, we cloned and characterized the full-length Fem1b cDNA from the freshwater prawn Macrobrachium nipponense (MnFem1b) in different tissues and at different developmental stages. Real-time quantitative reverse polymerase chain reaction (RT-qPCR) showed that the MnFem1b gene was expressed in all investigated tissues, with the highest expression level found in the testes. The results revealed that the MnFem1b gene might play roles in aspects of development of the male prawn phenotype. The RT-qPCR also revealed that MnFem1b mRNA expression was significantly increased at 10 days after metamorphosis. The expression levels in all investigated tissues showed a certain degree of sexually dimorphism, the expression levels in males were significantly higher than those in females (P < 0.05). Notably, the highest expression of MnFem1b was found in the testes. The expression of MnFem1b in different tissues indicates that it plays multiple biological functions in M. nipponense.

Nitric oxide synthase (NOS) produces nitric oxide (NO) by catalyzing the conversion of l-arginine to l-citrulline, with the concomitant oxidation of nicotinamide adenine dinucleotide phosphate. Recently, various studies have verified the importance of NOS invertebrates and invertebrates. However, the NOS gene family in the oriental river prawn Macrobrachium nipponense is poorly understood. In this study, we cloned the full-length NOS complementary DNA from M. nipponense (MnNOS) and characterized its expression pattern in different tissues and at different developmental stages. Real-time quantitative polymerase chain reaction (RT-qPCR) showed the MnNOS gene to be expressed in all investigated tissues, with the highest levels observed in the androgenic gland (P < 0.05). Our results revealed that the MnNOS gene may play a key role in M. nipponense male sexual differentiation. Moreover, RT-qPCR revealed that MnNOS mRNA expression was significantly increased in post-larvae 10 days after metamorphosis (P < 0.05). The expression of this gene in various tissues indicates that it may perform versatile biological functions in M. nipponense.

Mixed 50Ni–50Ti powders were milled in an attritor high energy ball mill and the structural evolution of the milled powders characterised by X-ray diffraction analysis. The microstrain, crystallite size, and lattice parameters of the nickel and titanium crystals were measured. The results show that increases in the rotational velocity and the total ball volume/tank volume ratio leads to a decrease in the crystallite size and rapid changes in the microstrain and lattice parameters, which enhance the amorphisation rate, thereby reducing the time required to obtain afully amorphous phase.MST/2079

Microstructural characterisation and room temperature tensile testing were performed on a series of tungsten heavy alloys extruded at various temperatures. Ultimate tensile strength of the alloys increased with increasing extrusion ratio and with decreasing extrusion temperature down to 600°C. Fracture surface observations indicated that the tensile strength correlated with the tungsten cleavage failure mode. The matrix could inhibit the propagation of cracks initiated in the tungsten particles.MST/3384