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Ovarian hormones, especially estrogen, may facilitate drug use vulnerability in females. Oxytocin is of special relevance to females and an important neuroendocrine factor regulating drug use. Mandarin vole (Microtus mandarinus) is a monogamous rodent, with complex nonsexual social behavior. Here, we examined whether ovariectomy produces effects on cocaine-induced aggressive behaviors, estrogen receptor alpha (ERα) and oxytocin in virgin female mandarin voles. The data indicate that repeated cocaine exposure increased aggressive behavior and reduced levels of oxytocin expression in the paraventricular nucleus in ovariectomized and sham-operated females. In addition, cocaine reduced the levels of ERα expression in the medial nuclei of the amygdale in sham-operated females. In contrast, cocaine decreased ERα expression in the medial preoptic area and increased serum estradiol levels in ovariectomized females. These results suggest that ovariectomy influences the effects of cocaine on central levels of ERα and oxytocin expression and serum estrogen levels. The estrogen system acts in concert with oxytocin to regulate cocaine-induced aggressive behavior in virgin females. [ABSTRACT FROM AUTHOR]

Internal friction (or damping) is a measure of energy dissipation during mechanical vibration. The internal friction peak induced by grain boundary (GB) relaxation was discovered by Kê in polycrystals in 1947. The GB internal friction and related anelastic effects have been successfully interpreted by Zener's anelastic theory and viscous sliding model. Since then, the GB internal friction peak has been widely used to study the dynamic process of GBs, impurity segregation at GBs and relevant processes in materials science. Previously, the GB internal friction was mostly studied with polycrystalline materials, in which mixed contributions of different types of GBs are involved. Since the microstructures and behaviors for different types of GBs are different, the detailed mechanism of the GB peak in polycryatals has not been clearly clarified. From the beginning of the 21th century, the internal friction in bicrystals (each has a single boundary) with different misorientations and rotation axes has been systematically investigated. The results indicate that the internal friction can be used to distinguish the individual behavior of different types of GBs and applied to the practice of “GB engineering.” Moreover, the coupling effect and compensation effect involved in GB relaxation has been recently observed and explained. The coupling effect means a correlated atomic motion occurred in GB relaxation. The compensation effect indicates that the apparent activation enthalpy is linearly related to the activation entropy in GB relaxation. These findings improve the understanding of the mechanism of GB internal friction. This article attempts to give a comprehensive review to the investigations of GB internal friction in polycrystals, bamboo-crystals, and bicrystals. The microscopic mechanisms and the further applications of GB internal friction are discussed and prospected. [ABSTRACT FROM AUTHOR]

The interaction problem of a piezoelectric screw dislocation dipole with a confocal elliptic blunt crack in elliptical inhomogeneity subjected to remote anti-plane stress field and in-plane electric field is investigated by using the complex method of elasticity. The exact closed-form solutions of a series of quantities, such as singularity stress field, image force and image torque acting on the center of screw dislocation dipole, stress intensity factor and electric displacement intensity factor of crack tip, energy release rate, and generalized strain energy density are obtained. Then the influence laws of remote load, the dip angle of dislocation dipole, the size of blunt crack, and the material constants on the quantities are analyzed. The numerical results show that the image force, image torque, stress intensity factor, and electric displacement intensity factor make periodic variation as the dip angle of dislocation dipole; the energy release rate of crack tip is negative when subjected to pure electric field, however, it can be positive or negative when subjected to the combined action of mechanical field and electric field; the sharp crack is not easy to expand in some combined action of mechanical field and electric field. [ABSTRACT FROM AUTHOR]

The addition of small percentages of Na+-montmorillonite (NaMMT) nanoclay does not appear to improve much the performance of thermosetting phenol-formaldehyde (PF) and phenol-urea-formaldehyde (PUF) resins used as adhesives for plywood and for wood particleboard. X-ray diffraction (XRD) studies indicated that NaMMT does not become completely exfoliated when mixed in small proportions to PF resins, contrary to that observed for acid-setting urea-formaldehyde (UF) resins. Differential scanning calorimetry (DSC) indicated that NaMMT has no accelerating effect on the curing of alkaline PF resins, contrary to that observed for UF resins. [ABSTRACT FROM AUTHOR]

The interaction between a screw dislocation and an interfacial cruciform crack and collinear linear cracks under loads at infinity was investigated. General solutions of complex potentials to this problem were derived by using complex potential theory. As illustrative examples, the closed form solution for a screw dislocation interacting with an interfacial cruciform crack and a linear crack is obtained. The stress intensity factor and critical stress intensity factor for dislocation emission are also calculated. The results show that the shielding effect increases with the increase of the shear modulus and the distance between the two cracks, but it decreases with the increase of dislocation azimuth and the distance between the dislocation and the cruciform crack tip. The critical loads at infinity for dislocation emission increase with the increment of the emission angle, the distance the two cracks and the vertical length of the cruciform crack. [ABSTRACT FROM AUTHOR]

Internal friction measurements were performed on various 〈111〉 tilt and twist grain boundaries in high-purity Al bicrystals. The temperature dependence of the grain boundary internal friction peak was determined, and the activation parameters of grain boundary relaxation were obtained. These parameters were found to change in a wide range depending on boundary geometry. The activation enthalpy of boundary relaxation and the pre-exponential factor of the relaxation time are related according to the compensation effect. The results are discussed in terms of the model of correlated relaxations. Bicrystals with vicinal Σ3 boundaries were observed to behave like single crystals, i.e. an internal friction peak did not appear. This evidences that both coherent and incoherent (60° 〈111〉 tilt) twins possess a high mechanical resistance. [ABSTRACT FROM AUTHOR]

We aimed to compare changes in insulin levels during an oral glucose tolerance test (OGTT) between women with normal glucose tolerance (NGT) during pregnancy and those with gestational diabetes mellitus (GDM). Overall, 105 pregnant women between 24 and 28 weeks' gestation, 50 with NGT and 55 with GDM according to NDDG standard, were enrolled into the study. The levels of fasting blood glucose, insulin, triglyceride (TG) and total cholesterol (TC) and the insulin levels, blood glucose levels at 1, 2 and 3 hours post oral glucose administration during an OGTT (5.8, 10.6, 9.2 and 8.1 mmol/L, respectively) were measured. Then, insulin resistance (IR) index was calculated. There was no significant difference in fasting, 3-h insulin levels and 3-h blood glucose levels between those with NGT and those with GDM (P > 0.05). However, 1-h and 2-h insulin levels, fasting and 1-h and 2-h blood glucose levels in women with GDM were significantly higher than those in the NGT group (P < 0.05). Fasting TC and TG levels in the GDM group were significantly higher than those with NGT (P = 0.031 and P = 0.025, respectively). Correlation analysis showed that TG and TC levels were positively correlated with homoeostasis model assessment-IR (HOMA-IR) (r = 0.67 and r = 0.78, respectively; P < 0.05). Our findings suggest that insulin sensitivity in women with GDM was significantly lower than that observed in those with NGT. Reducing IR and blood lipids in women with GDM could potentially improve maternal and foetal outcomes. [ABSTRACT FROM AUTHOR]

In [8-118, 9, 10, 11] a superconvergence analysis is derived for the smooth and singular Poisson equations by the finite difference method (FDM) using the Shortley-Weller approximation. In this article, we explore the superconvergence analysis for a parabolic equation using the Shortley-Weller approximation and the Crank-Nicolson scheme (CNS) in space and time discretization, respectively, denoted simply as FDM-CNS. The results of derivative superconvergence in [8-118, 9, 10, 11] can be extended to parabolic problems of smooth and singular solutions. The main results are as follows: when [image omitted] and [image omitted], the superconvergence rate O(h2 + k2) is derived for the solution derivatives in discrete H1 norms by the FDM-CNS on rectangular domains, where k is the time mesh spacing in the Crank-Nicolson scheme and h is the maximal mesh length of difference grids used. Note that the difference grids are not confined to be quasi-uniform, and local refinements are allowed for the solutions with unbounded derivatives. Numerical experiments are provided to support the superconvergence O(h2 + k2). [ABSTRACT FROM AUTHOR]

A theoretical model is proposed for elastic stress relaxation of a buried strained cylindrical inhomogeneity, which assumes the edge misfit dislocation dipole formation in the soft matrix at some distance from the interface. The critical radius of the inhomogeneity for the formation of the edge misfit dislocation dipole is given and the influence of various parameters on the critical radius is evaluated. The result indicates that the critical radius decreases with increasing misfit strain and core radius of the misfit dislocation. It is also found that, compared to the edge misfit dislocation dipole formation in the interface, the critical radius of the inhomogeneity decreases when the location of an edge misfit dislocation dipole formation is in the soft matrix at some distance from the interface. [ABSTRACT FROM AUTHOR]

Sun light energy is used by plants to trigger their growth and development. However, an increase of UV-B light may lead to DNA damage. DNA photolyases are enzymes that repair the cyclobutane pyridine dimer (CPD) and 6-4 photoproduct lesions formed through UV irradiation of DNA. Many aspects of the repair process are under intense scientific investigation but still poorly understood. Here we have computationally analysed DNA-photolyases using the resonant recognition model (RRM), a physico-mathematical approach based on digital signal processing methods. The RRM proposes that protein interactions represent the transfer of resonant electromagnetic energy between interacting molecules at the particular frequency. Within this study we have determined photolyases characteristic frequency, "hot spots" amino acids corresponding to the functional mutations and functional active/binding sites, and designed photolyase peptide analogous. A mutual relationship between photolyase and p53 tumour suppressor protein has also been investigated. The results obtained provide new insights into the structure-function relationships of photolyase protein family. [ABSTRACT FROM AUTHOR]

Tea cultivars 'Xiaoxueya' and 'White leaf No. 1' have been bred from natural albino mutants of tea plants (Camellia sinensis) and have white tea shoots when the environmental temperature is below 20°-22°C in the early Spring. White tea shoots are used to produce high grades of unfermented tea in China because of their special leaf colour and flavour. The chemical compositions of their shoots were determined by high performance liquid chromatography and compared with 'Zhenong-113', a common tea cultivar used for green tea production. Eighteen amino acids and eight catechins were detected in the three cultivars examined, of which theanine was the most abundant amino acid, followed by arginine, glutamic acid, histidine, aspartic acid and threonine. The most abundant catechin was (-) epi-gallocatechin gallate (EGCg), followed by (-) epi-catechin gallate (ECg), and (-) epi-gallocateclhin (EGC). Both albino cultivars had significantly higher total amino acid concentrations, but significantly lower concentrations of total catechins and caffeine than 'Zhenong-113'. The relative compositions of amino acids and catechins differed between both albino mutants and 'Zhenong-113'. Six out of the 18 amino acids occurred at higher levels in the mutants, four were at lower levels, six showed no difference, and the remaining two were not consistent. ECg and epi-catechin (EC) showed significantly lower levels, but EGC showed higher levels in the mutants, and no differences were observed for EGCg, (-) gallocatechin gallate (GCg) and (-) catechin gallate (Cg), while (-) gallocatechin (GC) and (-) catechin (C) were not consistent. [ABSTRACT FROM AUTHOR]

Absorbing boundary conditions for computational aeroacoustics (CAA) are reviewed. Commonly used absorbing zonal techniques, such as sponge layers and buffer zones, as well as perfectly matched layers (PML) are discussed. The basic ideas and central results of these methods are surveyed and summarized. Special attention will be given to the recently emerged PML technique and its application to CAA. Numerical examples are presented for PML in duct acoustics. A comparison of PML and non-PML absorbing boundary conditions will also be given. [ABSTRACT FROM AUTHOR]

The deployment of hyperthermia as a routine adjuvant to radiation or chemotherapy is limited largely by the inability to devise treatment plans which can be monitored through temperature distribution feedback during therapy. A non-invasive microwave tomographic thermal imaging system is currently being developed which has previously exhibited excellent correlation between the recovered electrical conductivity of a heated zone and its actual temperature change during phantom studies. To extend the validation of this approach in vivo, the imaging system has been re-configured for small animal experiments to operate within the bore of a CT scanner for anatomical and thermometry registration. A series of 5–7 day old pigs have been imaged during hyperthermia with a monopole antenna array submerged in a saline tank where a small plastic tube surgically inserted the length of the abdomen has been used to create a zone of heated saline at pre-selected temperatures. Tomographic microwave data over the frequency range of 300–1000MHz of the pig abdomen in the plane perpendicular to the torso is collected at regular intervals after the tube saline temperatures have settled to the desired settings. Images are reconstructed over a range of operating frequencies. The tube location is clearly visible and the recovered saline conductivity varies linearly with the controlled temperature values. Difference images utilizing the baseline state prior to heating reinforces the linear relationship between temperature and imaged saline conductivity. Demonstration of in vivo temperature recovery and correlation with an independent monitoring device is an important milestone prior to clinical integration of this non-invasive imaging system with a thermal therapy device. [ABSTRACT FROM AUTHOR]

Evaluation of a laboratory-scale microwave imaging system for non-invasive temperature monitoring has previously been reported with good results in terms of both spatial and temperature resolution. However, a new formulation of the reconstruction algorithm in terms of the log-magnitude and phase of the electric fields has dramatically improved the ability of the system to track the temperature-dependent electrical conductivity distribution. This algorithmic enhancement was originally implemented as a way of improving overall imaging capability in cases of large, high contrast permittivity scatterers, but has also proved to be sensitive to subtle conductivity changes as required in thermal imaging. Additional refinements in the regularization procedure have strengthened the reliability and robustness of image convergence. Imaging experiments were performed for a single heated target consisting of a 5.1 cm diameter PVC tube located within 15 and 25 cm diameter monopole antenna arrays, respectively. The performance of both log-magnitude/phase and complex-valued reconstructions when subjected to four different regularization schemes has been compared based on this experimental data. The results demonstrate a significant accuracy improvement (to 0.2° C as compared with 1.6° C for the previously published approach) in tracking thermal changes in phantoms where electrical properties vary linearly with temperature over a range relevant to hyperthermia cancer therapy. [ABSTRACT FROM AUTHOR]

Rapid moisture adsorption by low-moisture rice grains may cause the grains to fissure. The combination of physical properties such as stress and strain has a continuous influence on the rice grain. Rice grains with stress fissures break more readily than sound kernels during harvesting, handling, milling, and transporting, and thereby reduce the quality and market value of the rice grain. Stress fissure detection remains one of the most important tasks in rice grain quality inspection. A machine vision system was used to obtain images of fissured rice grains. The system consisted of a CCD (Charge Coupled Device) black/white camera, an image frame grabber, and a computer. An image processing program (Image-Pro Plus) was used to study and evaluate the images. The procedures to detect fissures in rice grain using Image-Pro Plus were developed. The fissure pattern difference between long and medium grain rice was recognized after analyzing the processed images of the fissured grains. The computer vision system with Image-Pro Plus used in our study was able to reveal 94% of all the fissure lines detected in medium rice samples by a human expert and 100% in long rice samples. [ABSTRACT FROM AUTHOR]

In this paper the anomalously amplitude-dependent internal-friction peak (the P[sub 3] peak) in cold-worked Al-Mg alloys is theoretically analysed by solving the bulk diffusion equations of the solute atoms under the action of dislocation drag in the case of a constant external stress. The results show that the bow-out distance of the dislocation has an exponential relation with time. Both the relaxation strength Delta and the relaxation time tau calculated by fitting the curves with a standard exponential creep function increase with increasing strain amplitude. The activation energy H and pre-exponential factor tau[sub 0] deduced from tau through the Arrhenius relation can be well described by a parabolic function with strain amplitude. The P[sub 3] peak is calculated from the data on Delta and tau by assuming that it obeys a standard Debye peak. The P[sub 3] peak shifts towards a higher temperature and gains in height when strain amplitude increases, which are in agreement with pertinent experiments. [ABSTRACT FROM AUTHOR]