Changes in endocrine profile and reproductive organs during puberty in the male marmoset monkey (Callithrix jacchus)

Data on pubertal maturation in male marmoset, a model for human reproduction, are scant and conflicting. We collected data on novel parameters to characterize puberty. Twenty-five marmoset monkeys were assigned to five age groups by weeks (wk): 21 (pre-pubertal), 43 (onset of puberty), 52 (fully pubertal), 70 (mature), and 116 (fully adult). Serum and intratesticular testosterone and pituitary bioactive chorionic gonadotropin (bioCG) were measured. Testicular development was assessed by ultrasonography, histology, and flow cytometry. Three consecutive blood samples revealed extreme fluctuations in testosterone concentrations, suggesting an erratic secretion. Age-related changes in serum testosterone and pituitary bioCG concentrations were observed. Intratesticular androgens (ITAs) showed high fluctuations within groups at all ages and were high in some animals by 21 wk. Unexpectedly, no correlation between pituitary bioCG and serum testosterone or ITAs was found, but these parameters significantly correlated with testicular weight and volume. These observations were consistent a dependence on the testis growth on bioCG. Unfortunately, the low serum levels of bioCG were not measurable in this study. At 43 wk, the animals reached puberty. At 52 wk of age, animals attained maximum body and epididymal weights and qualitatively normal spermatogenesis, but testes continued growing, reaching a maximum of all parameters at 70 wk of age, without further major changes at the age of 116 wk. It is concluded that (1) gonadal activation is evident at wk 21, (2) the male marmoset reaches the pubertal threshold around 43 wk of age, attains qualitative parameters at 52 wk, matures further to sexual maturity at 70 wk, and (3) serum testosterone and ITAs are highly variable without any identifiable correlation with pituitary bioCG.     

Inhibition of lipase from rice (Oryza sativa) by diethyl-p-nitrophenyl phosphate

The inhibition of rice bran lipase (RBL) by diethyl-p-nitrophenyl phosphate was studied with reference to kinetics, nature of inhibition and also elucidate the effect of the inhibitor on the structure—function of the enzyme. Enzyme activity measurements shows that the inhibitor is more effective at 0.050 mM concentration of diethyl-p-nitrophenyl phosphate and the activity is 50% at this level of inhibitor concentration. The affinity of substrate for the enzyme was observed by the increase in the velocity of the reaction with increase in the substrate concentrations and double reciprocal plot indicates that the inhibition followed a competitive in nature and inhibition constant K _i is found to be 0.016 mM at pH 7.0. The decrease in apparent thermal denaturation temperature to 4 °C compared to control indicates the destabilization of enzyme in the presence of inhibitor. Fluorescence spectral measurements suggests that pronounced quenching of fluorescence intensity of RBL occurs at higher concentrations of diethyl-p-nitrophenyl phosphate and ‘K _a’ value was found to be 2.4 × 10⁴ M⁻¹ with free energy change ΔG^o—26 kJ/mol at 30 °C suggesting strong binding between the enzyme and the inhibitor with microenvironmental changes occur at the active site or in the neighbourhood of active site. The far UV-CD data suggest that there is no significant changes in the conformation of the enzyme as a result of binding of diethyl-p-nitrophenyl phosphate. These results indicate that diethyl-p-nitrophenyl phosphate is a inhibitor of RBL and binds to the enzyme in brining about inhibition without any structural alterations.     

Classical and Differential Thermal Analysis Studies of the Glass-Ceramic Transformation in a YSiAlON Glass

Nucleation and crystallization studies were conducted on a YSiAlON glass that contained 17 equiv.% nitrogen (7.5 at.%) by using a two-stage nucleation-and-growth treatment. Classical and differential thermal analysis (DTA) techniques were both used to study the crystallization process, to ensure that the optimum heat-treatment schedule that yielded a fine microstructure and minimum residual glass was applied. The optimum nucleation and crystallization temperatures were determined from DTA traces that were recorded from isothermal heat treatments at different nucleating temperatures, ranging between T _g - 40°C and T _g+ 100°C for 1 h and crystal-growth temperatures in the range of 1170°-1310°C for 0.5 h, respectively. The activation energy for the crystallization process was determined, based on the analysis of the variation of peak temperature at five different heating rates. Specimens heat treated in a tube furnace under nitrogen gas were subjected to microscopical investigation, and results showed variations in the volume fraction of crystalline phases and crystal size with nucleation temperature. The nucleation temperature, T _g+ 40°C (1025°C), which corresponded to the maximum volume fraction of crystalline phases and minimum crystal size, was consistent with the optimum nucleation temperature, T _g+ 35°C (1020°C), as determined from DTA. The time and temperature of nucleation and crystal growth dictated the nature and size of the crystalline phases. Properties such as hardness and density were assessed and correlated to the nucleation temperature. The influence of sample specific surface on the devitrification mechanisms was estimated, and bulk nucleation was observed to be the dominant nucleation mechanism.     

A delay and energy aware coordination mechanism for WSAN

In this paper, a delay and energy aware coordination mechanism (DEACM) has been devised for wireless sensor–actor networks. In DEACM, a two‐level hierarchical K‐hop clustering mechanism is used to organize the sensors and actors for communication. In the first level, sensors form a K‐hop cluster using actors as cluster heads, and sink is made as the cluster head in the second level to form a cluster among actors. Sensor nodes, which are 1‐hop away from the actors, also called as relay nodes are elected as backup cluster head (BCH) based on the residual energy and node degree. BCH collects the data from sensors when an actor is away to perform actions in the affected area. The scheme is evaluated through exhaustive simulation in NS2 along with other existing schemes. Different parameters like average event waiting time, event reliability, and average energy dissipation are compared, varying the number of sensors, actors, and data transfer rate. In general, it is observed that the proposed DEACM outperforms other existing schemes. Copyright © 2016 John Wiley & Sons, Ltd.     

Experimental investigation and multiresponse genetic optimization of drilling parameters for self-healing GFRP

Journal of Mechanical Science and Technology - Self-healing materials heal partially or completely when damage occurs to restore the functionality of the material. Self-healing technology has found...     

RESRES: The story behind the paper “Research in software engineering: An analysis of the literature”

This article is a background report describing a comprehensive study of research in the three computing disciplines Computer Science, Software Engineering, and Information Systems. Findings relate to research topics, approaches, methods, reference disciplines, and levels of analysis. The article informally describes the process used and the research products produced.     

Failure Analysis of AISI 440C Steel Ball Screws Used in the Actuator System of a Satellite Launch Vehicle

In view of its excellent wear and corrosion resistance, AISI 440C steel is the material of choice for the fabrication of ball screws used in actuator systems of satellite launch vehicles. During the routine acceptance test of a ball screw, longitudinal cracks were observed at the shaft location of the ball screw. The optical microstructure of the ball screw material (AISI 440C) revealed the presence of aligned carbides (carbide banding). Fractographic observations revealed the cracking to be along the carbide bands. Based on detailed optical and scanning electron microscopic observations, the cracking of the ball screws was attributed to the carbide bands.     

Electron spin resonance and AC susceptibility studies on La0.9Pb0.1MnO3 single crystals

Phase separation has been recognized as important properties of manganite to create colossal magnetoresistance (CMR). Frequency dependence of AC susceptibility and electron spin resonance (ESR) studies confirm the phase separated glassy magnetism in the La_0.9Pb_0.1MnO₃ crystals. ESR spectra exhibit a gradual narrowing of the asymmetric FMR signals upon increasing the temperature and approaching the Curie temperature (T_c). The temperature dependence of line width (ΔH_pp), g-factor, double integrated (I) intensity of the resonance signals and frequency dependence peak temperatures are discussed in this paper to explain inhomogeneity in the La_0.9Pb_0.1MnO₃ single crystals.