Pulsed electron beam irradiation of dilute aqueous poly(vinyl methyl ether) solutions

A dilute aqueous solution of the temperature-sensitive polymer, poly(vinyl methyl ether) (PVME), was irradiated by a pulsed electron beam in a closed-loop system. At temperatures, below the lower critical solution temperature (LCST), intramolecular crosslinked macromolecules, nanogels, were formed. With increasing radiation dose D the molecular weights M_w increase, whereas the dimensions (radius of gyration R_g, hydrodynamic radius R_h) of the formed nanogels decrease. The structure of the PVME nanogels was analyzed by field emission scanning electron microscopy (FESEM) and globular structures with d=(10-30) nm were observed. The phase-transition temperature of the nanogels, as determined by cloud point measurements, decreases from T_cr=36 °C (non-irradiated polymer) to T_cr=29 °C (c_p=12.5 mM, D=15 kGy), because of the formation of additional crosslinks and an increase in molecular weights. The same behavior was observed for a pre-irradiated PVME (γ-irradiation) with higher molecular weight due to intermolecular crosslinks. After pulsed electron beam irradiation the molecular weight again slightly increases whereas the dimension decreases. Above D=1 kGy the calculated ρ-parameter (ρ=R_g/R_h) is in the range of ρ=0.5-0.6 that corresponds to freely draining globular structures.     

Magnetoresistance and Irreversibility Fields of Bismuth-Based 1G Tape

The magnetoresistance and irreversibility fields of commercial bismuth-based 1G tape were studied on the basis of the temperature dependencies of the magnetoresistance at the two relative orientations of magnetic field and superconductor plane. The critical temperatures of this tape are the following: T _{c50 %} = 110.3 K and T _c0 = 109.9 K, and the width of superconducting transition is ΔT = 0.5 K. The widths of the transition to the superconducting state versus applied magnetic fields were derived for both orientations. The experimental data were fitted using the formula ΔT = C H ^m + ΔT ₀. The irreversibility field values were obtained and successfully fitted as a function of temperature. At 77 K, they were found to amount to H _{i r r} = 72.8 kOe and H _{i r r} = 5.5 kOe for the parallel and perpendicular directions, respectively.     

A new approach to power estimation and reduction in CMOS digital circuits

Modelling and optimization of dynamic capacitive power consumption in digital static CMOS circuits, taking into consideration a reason of a gate switching—gate control mode, is discussed in the present paper. The term ‘gate control mode’ means that a number and type of signals applied to input terminals of the gate have an influence on total amount of energy dissipated during a single switching cycle. Moreover, changes of input signals, which keep the gate output in a steady state, can also cause power consumption. Based on this observation, complex reasons of power losses have been considered. In consequence, the authors propose a new model of dynamic power consumption in static CMOS gates. Appropriate parameters’ calculation method for the new model was developed. The gate power model has been extended to logic networks, and consequently a new measure of the circuit activity was proposed. Switching activity, which is commonly used as a traditional measure, characterizes only the number of signal changes at the circuit node, and it is not sufficient for the proposed model. As the power consumption parameters of CMOS are dependent on their control mode, the authors used probability of the node control mode as a new measure of the circuit activity. Based on the proposed model, a procedure of combinational circuit optimization for power dissipation reduction has been developed. The procedure can be included in a design flow, after technology mapping. Results of the power estimation received for some benchmark circuits are much closer to SPICE simulations than values obtained for other methods. So the model proposed in this study improves the estimation accuracy. Additionally, we can save several percent of the consumed energy.     

Multiple familial gastrointestinal autonomic nerve tumors and small intestinal neuronal dysplasia

A novel two-dimensional electrophoresis system to be carried out on polyacrylamide gels under nondenaturing conditions was developed to efficiently fractionate the peptides resulting from endoproteinase digestion of 32P-labeled proteins. In particular, nondenaturing gel isoelectric focusing was combined with alkaline 40% polyacrylamide gel electrophoresis to generate phosphopeptide maps with high reproducibility, thus allowing both protein fingerprinting and comparative analysis of different samples. The potential application of this method for subsequent amino acid sequencing of the isolated phosphopeptides was further demonstrated by successful manual and automated Edman sequencing. Taken together these data show that such a simple and precise approach is suitable for both analytical and preparative aims.     

Vorwort

Ohne Zusammenfassung     

The Role of ER Stress-Related Phenomena in the Biology of Malignant Peripheral Nerve Sheath Tumors

Malignant peripheral nerve sheath tumors (MPNST) are rare but one of the most aggressive types of cancer. Currently, there are no effective chemotherapy strategies for these malignancies. The inactivation of the neurofibromatosis type I (NF1) gene, followed by loss of TP53, is an early stage in MPNST carcinogenesis. NF1 is a negative regulator of the Ras proteins family, which are key factors in regulating cell growth, homeostasis and survival. Cell cycle dysregulation induces a stress phenotype, such as proteotoxic stress, metabolic stress, and oxidative stress, which should result in cell death. However, in the case of neoplastic cells, we observe not only the avoidance of apoptosis, but also the impact of stress factors on the treatment effectiveness. This review focuses on the pathomechanisms underlying MPNST cells physiology, and discusses the possible ways to develop a successful treatment based on the molecular background of the disease.     

Effects of probiotic L. plantarum 299v on consumer quality,accumulation of phenolics,antioxidant capacity and biochemical changes in legume sprouts

This study evaluated the influence of Lactobacillus plantarum 299v on the consumer quality of legume sprouts. The probiotic-rich sprouts were produced by soaking the seeds in probiotic water suspension and further sprouting at 25 °C for 4 days. The enrichment of the sprouts with L. plantarum 299v only slightly affected the sensory quality - the overall acceptability of the probiotic-rich sprouts was usually higher. The probiotic-rich sprouts exhibited increased activity of polyphenol oxidase (the highest activity in the mung bean preparations - 73.97 U mg⁻¹ of protein). The peroxidase activity was not altered. The probiotic enrichment increased the phenolic content by 25%, 31% and 23% in the soybean, adzuki and mung bean preparations; however, it was not reflected in the antioxidant activities. The changes in the activity of enzymes involved in mobilisation of stored material (starch and proteins) and the increased content of phenolics only slightly modified the bioavailability of nutrients.     

Microencapsulation in foam spray drying

Abstract

The article presents the results of the experiments of gas-admixing foam spray drying microencapsulation of oil in co-current spray drying tower. The introduction of a foaming gas resulted in a decrease of encapsulation efficiency: for high foaming gas/liquid ratio (GLR) 6.43·10^?3 kg/kg and T_air,0=215?°C by over 50% relative to the non-foaming process due to damage of the microcapsule structure and leakage of the oil phase to the particle surface. For moderate drying temperatures and GLR, 80% of microencapsulation efficiency might be achieved with simultaneous control of selected product properties like apparent and bulk density or angle of repose. Abbreviations GLR gas-to-liquid ratio

HR Hausner ratio

MDX maltodextrin

PSD particle size distribution

SEM scanning electron microscope.

     

Magnetron sputtering as a method for introducing catalytic elements to magnesium hydride

Magnesium hydride is a very interesting material suggested to be used for storing hydrogen because of its high capacity (～7.5 wt%). However its application is limited by high decomposition temperature and poor kinetics. This paper presents results of the preliminary study on the new approach to introduction of surface dopants by magnetron sputtering on powdery substrates. Thin films of nickel were successfully deposited on the magnesium hydride powder. SEM observations and EDS elements mapping show uniform and continuous layers, with the thickness up to 320 nm, formed on hydride grains. It was proven by measurements with Sievert's method that such a surface modification increases the H₂ dissociation/recombination speed and effectively enhances hydrogenation/dehydrogenation reaction rate. The DSC measurements show the reduction of the activation energy of hydrogen desorption by ～150 kJ/mol and a decrease of the decomposition temperature by 50 K. The study shows that uniform nickel coating of hydride powder by magnetron sputtering can be considered as an effective way for introduction of the catalytic elements and improvement of the hydrogen storage properties of the magnesium hydride.