Developmental expression of pIgR gene in sheep mammary gland and hormonal regulation

Secretory IgA found in external secretions are constituted by polymeric IgA (pIgA) bound to the extra-cellular part of the polymeric immunoglobulin receptor (pIgR). The receptor mediates transcytosis of pIgA across epithelial cells. The aim of the present study was to analyse the evolution of pIgR expression in the sheep mammary gland during the development of the mammary gland and to analyse its hormonal regulation. Gene expression of the pIgR was analysed in sheep mammary gland during pregnancy and lactation. By Northern Blot analysis, we observed that low levels of pIgR mRNA are expressed until day 70 of pregnancy. Accumulation of pIgR mRNA started during the third part of pregnancy and intensified 3 d after parturition to reach highest levels during established lactation (day 70). In situ hybridization analysis was used to confirm the increase in pIgR gene expression per mammary epithelial cell. In order to examine the hormonal regulation of the pIgR expression, virgin ewes were hormonally treated. Treatment with oestradiol and progesterone increased pIgR mRNA levels slightly. Subsequent addition of gluocotricoids induced a significant accumulation of pIgR mRNA in the mammary gland of the treated animals. Immunohistochemical analysis was performed to verify that the increase of pIgR mRNA level was associated with enhancement of the pIgR protein in mammary cells. No increase of pIgR mRNA levels were observed if PRL secretion was blocked by bromocryptine injections throughout the hormonal procedure. In conclusion, the present experiments suggest that the enhancement of pIgR levels during lactation result from combined effects of both prolactin and glucocorticoids.     

Modelling of hydrogen induced pressurization of internal cavities

Internal cavities can constitute a crack initiation site especially if filled with hydrogen at high pressure. A new refined equation of state based on recent NIST database has been introduced in order to model the equilibrium pressure. It is based on a thermodynamic definition of fugacity and uses the NIST data relating hydrogen density and pressure to define a new fugacity pressure quadratic dependence. The resulting Equation Of State (EOS) is compared to the standard Abel–Noble EOS and it is shown that for a given fugacity, imposed by a Sievert's law, the corresponding pressure is significantly higher. This new refined EOS was introduced into a previously developed numerical model of hydrogen diffusion and desorption and applied to evaluate the kinetics of pressure build-up within a cavity and its equilibrium pressure. It has been shown that the kinetics of pressure build-up at room temperature, which reaches values close to equilibrium in some hundreds of hours, is compatible with the industrial quality control procedures. The calculated pressures are in the range 4500–8650 bars depending on hydrogen solubility, which differs between the matrix and the segregation bands, and tend to equilibrium values obtained from mass balance approach.     

Adaptive AR and neurofuzzy approaches: access to cerebral particle signatures.

In recent years, a relationship has been suggested between the occurrence of cerebral embolism and stroke. Ultrasound has therefore become essential in the detection of emboli when monitoring cerebral vascular disorders and forms part of ultrasound brain-imaging techniques. Such detection is based on investigating the middle cerebral artery using a TransCranial Doppler (TCD) system, and analyzing the Doppler signal of the embolism. Most of the emboli detected in practical experiments are large emboli because their signatures are easy to recognize in the TCD signal. However, detection of small emboli remains a challenge. Various approaches have been proposed to solve the problem, ranging from the exclusive use of expert human knowledge to automated collection of signal parameters. Many studies have recently been performed using time-frequency distributions and classical parameter modeling for automatic detection of emboli. It has been shown that autoregressive (AR) modeling associated with an abrupt change detection technique is one of the best methods for detection of microemboli. One alternative to this is a technique based on taking expert knowledge into account. This paper aims to unite these two approaches using AR modeling and expert knowledge through a neurofuzzy approach. The originality of this approach lies in combining these two techniques and then proposing a parameter referred to as score ranging from 0 to 1. Unlike classical techniques, this score is not only a measure of confidence of detection but also a tool enabling the final detection of the presence or absence of microemboli to be performed by the practitioner. Finally, this paper provides performance evaluation and comparison with an automated technique, i.e., AR modeling used in vitro.     

Cathodic electrochemical detection of sonochemical radical products

This paper reports on an electrochemical technique for the detection of oxidizing radical species, produced as the result of cavitation induced by ultrasound. A study of two example reactions is reported: the Weissler reaction and the Fricke reaction. In both cases, redox-active materials trap oxidative radicals. Electrochemical detection within a flow cell system is then used to sense redox-active products of the reactions between a chosen trapping agent and radicals produced within an ultrasonically irradiated aqueous solution. A demonstration of the sensitivity of electrochemical detection of radical products is presented. An equivalent dose of the ultrasonic reactor is reported.     

Chemical Forces,Structure, and Gelation Properties of Sweet Potato Protein as Affected by pH and High Hydrostatic Pressure

Sweet potato is one of cheap sources for starch industries worldwide, and exploiting starch wastewater as an alternative protein source is mainly environmental and economic concerns. In this study, the effects of high hydrostatic pressure (HHP; 250, 400, and 550 MPa) on chemical forces, structure, and gelation properties of sweet potato protein (SPP) at pH 3.0, 6.0, and 9.0 were investigated. The values of surface hydrophobicity (H_o) and absolute value of zeta potential of SPP significantly increased from 250 to 550 MPa (p?<?0.05) at all three pH conditions. The total amount of sulfhydryl (-SH-) groups in SPP decreased after HHP at pH 9.0, whereas the amount of free -SH- increased. High molecular mass aggregates (>?180 kDa) were observed in SPP after HHP at pH 6.0 and 9.0 by SDS-PAGE. Regarding elastic rheological behaviors, storage modulus (G′) values of SPP were significantly strengthened after HHP treatment. In addition, textural properties and water-holding capacity of gels made from SPP after 250 and 400 MPa at pH 9.0 were significantly improved, and the gels showed a compact and uniform gel network with the contribution of immobilized water fractions. The gel properties exhibited by SPP after HHP treatment at different pH levels, in particular after 400 MPa at pH 9.0, suggested that it could be potential protein resources as new gelling reagent in the food system.