Effect of reducing agents on the structure of zinc oxideunder microwave irradiation

Zinc oxide was synthesized from zinc sulphate using different reducing agents under microwave irradiation.The influence of sodium borohydride, hydrazine
hydrate and urea on the shape and size of the products were investigated by scanning electron microscopy (SEM) and  X- ray diffraction (XRD). SEM showed the nano-sized spherical and rectangular shaped structures in case of sodium borohydride and hydrazine hydrate, whereas micro-sized hexagonal structures were formed in case of urea under the same irradiation power. The reducing agents played an important role in forming the various structures.
Thus different shapes and size of structures were produced by only varying the reducing agent, which had wide applications in various fields.     

Molecular weight dependence in a relaxation phenomenon at glassy state: Physical aging of polycarbonate

At the glassy state of polymers, the reptation-type molecular motion should be frozen-in and the relaxation should be only by local motions, such as rotation, vibration, and torsion. Such local motions would not depend on molecular weight. This may be current understanding of the polymer glass. By contrast, we found that the rate of enthalpy relaxation in polycarbonate at 100 °C (50 °C below T_g) clearly depends on molecular weight. Deterioration of impact strength was also found to depend on molecular weight. The surprising results are presented in this letter.     

Contraception in mice immunized with recombinant zona pellucida subunit 3 proteins correlates with Th2 responses and the levels of interleukin 4 expressed by CD4+ cells

The immune responses and contraceptive effect in mice were tested following immunization with purified recombinant zona pellucida (ZP) proteins produced using a vaccinia (v) virus T7 mammalian expression system. Female BALB/c and CBA mice were immunized with recombinant mouse (m) ZP3 (vmZP3) or pig (p) ZPC (vpZPC) using Freund's adjuvants and boosted three times. Fertility and mean litter size were significantly reduced in groups of BALB/c mice immunized with recombinant vmZP3 and vpZPC compared with controls treated with Freund's adjuvants alone. In CBA mice, fertility and mean litter size were significantly reduced in groups of animals immunized with vmZP3 but not with vpZPC compared with the controls. Most infertile animals treated with vmZP3 and a single infertile BALB/c mouse treated with vpZPC lacked mature follicles in the ovaries, whilst no abnormalities were detected in the remaining vpZPC treated, fertile vmZP3 treated and control mice. All mice (both fertile and infertile) immunized with vmZP3 and vpZPC produced IgG antibodies, but the levels of total IgG, IgG1 and IgG2a did not correlate with infertility. All BALB/c and CBA mice immunized with vmZP3 and vpZPC showed greater delayed type hypersensitivity responses in the footpads after challenge with their respective antigens than controls, but these did not differ between the fertile and infertile mice. There was, however, a significant correlation between infertility and the levels of the Type 2 T helper cell (Th2) cytokine interleukin 4 produced by CD4+ cells from vmZP3 immunized mice in response to stimulation with vmZP3 and this did not apply to the levels of the Type 1 T helper cell (Th1) cytokine interferon gamma or the general proliferation response. The results support the conclusion that induction of Th2 responses in individual mice determines whether infertility develops in response to immunization with zona pellucida proteins.     

On the usage of resonate and fire dynamics in the complex oscillation‐based test approach

Resonate and Fire (R+F) models were introduced to account for many phenomena occurring in biological neurons showing sub‐threshold oscillations of the membrane potential. In information technology, they are at the basis of Chaotic Spiking Oscillators (CSOs), exploitable in Pulse Coupled Neural Networks (PCNNs). This paper illustrates how the R + F paradigm can also be used for the testing of analog signal processing structures (and specifically filters), extending the Oscillation Based Test (OBT) framework. The rich dynamics of the R + F model is used to encode the block under test features and faults into pulse trains directly processable at the digital level. Means to achieve a precise characterization of firing times are provided and used for parametric testing. Considerations about the trade‐off between testing times and accuracy are provided together with a practical example and simulation data. Copyright © 2012 John Wiley & Sons, Ltd.     

Charge resolution of plastic track detectors used to identify relativistic nuclei

We present measurements of charge resolution in the plastic track detectors CR39(DOP) and Tuffak polycarbonate over the region 10≤$\text{Z}\text{β ≤105}$, determined from plastic stacks exposed to projectile fragments of 1.29 $\text{GeV}\text{u}$¹³⁹La, 1.45 $\text{GeV}\text{u}$⁸⁴Kr, and 1.70 $\text{GeV}\text{u}$⁵⁶Fe produced by nuclear interactions within the stacks, and to 0.96 $\text{GeV}\text{u}$²³⁸U and 1.0 $\text{GeV}\text{u}$¹⁹⁷Au ions. The charge resolution obtained is shown to be comparable to the irreducible limit set by fluctuations in energy loss and is consistent with that expected of a track-formation model based on the effects of both K-shell ionization and restricted energy loss.     

Continuous estimation of CO2 production during exercise

A new method was developed for continuous isotopic estimation of human whole body CO2 rate of appearance (Ra) during non-steady state exercise. The technique consisted of a breath-by-breath measurement of 13CO2 enrichment (E) and a real-time fuzzy logic feedback system which controlled NaH13CO3 infusion rate to achieve an isotopic steady state. Ra was estimated from the isotope infusion rate and body 13CO2 enrichment which was equal to E at the isotopic steady state. During a non-steady state incremental cycle exercise (5 w/min or 10 w/min), NaH13CO3 infusion rate was successfully increased by the action of feedback controller so as to keep E constant.     

Lindeman's melting law and solidus curve under pressure of Al–Si and Al–Ge solid solutions

Using the pressure dependence of the mean-square displacement, the compression effect on the melting temperature of matrix Al is studied by Lindeman's melting law. The melting curve obtained increases as a function of the pressure and is in good agreement with the observed tendency for Al. The contribution of the transverse-like acoustic modes to the mean-square displacement is important for Al and becomes more predominant under pressure. Then, considering the contributions from the band and local mode frequencies, the temperature- and pressure-dependent mean-square displacement is quantitatively calculated for Al–Si and Al–Ge solid solutions. The concentration dependence of the Debye temperature at high and low temperatures is estimated, and the pressure effect on the solidus curves is presented by applying Lindeman's melting law to the Al–Si and Al–Ge alloy systems. © 1998 Chapman & Hall     

Androgen regulation of hypothalamic neurons containing gonadotropin-releasing hormone in a cichlid fish: integration with social cues

Reproduction in vertebrates is regulated by internal signals such as hormone levels and by external signals such as social interactions. In an African cichlid fish, Haplochromis burtoni, the effect of social interactions is evident in the hypothalamo-pituitary-gonadal (HPG) axis of males. Territorial males, characterized by aggressive and reproductive activity, have significantly larger hypothalamic gonadotropin-releasing hormone (GnRH)-containing neurons and larger testes than nonterritorial males. Furthermore, a switch in the social status of an adult male causes a corresponding change in GnRH neuron size and testis size. Here we show that the GnRH-containing neurons in the hypothalamus of adult territorial males are also influenced by gonadal hormones. Castration of territorial males caused GnRH neurons to increase in size. This neuronal hypertrophy in castrated animals was prevented either by testosterone (T) or 11-ketotestosterone (KT) treatment. Estradiol (E2) treatment did not reduce GnRH cell size in castrated animals. These results suggest that androgens reduce the size of GnRH cells through negative feedback. Since E2 had no effect, androgen influence on GnRH cell size appears to be independent of aromatization. These data are consistent with the hypothesis that the setpoint for hypothalamic GnRH cell size is determined by social cues and that this setpoint is maintained by negative feedback from gonadal androgens.