Interactions of oxidized lipids with protein. Part XVI. Interactions of oxidized ethyl linoleate with collagen

The reaction of ethyl linoleate with collagen proceeded at 60 degrees C following the first order kinetics but during the hydroperoxide decomposition the rate constant of the first order decomposition was substantially lower than that of the second order decomposition. Contrary to cellulose, collagen catalyzed the hydroperoxide decomposition. The amount of total oxidation products rose rapidly at the stage of rapid hydroperoxide formation, and slowly afterwards. The browning reaction was fasted in the stage of maximum hydroperoxide content, and both ether-insoluble and ether-soluble pigments were formed, the latter low in nitrogen. The amount of lipid oligomers increased mainly in the reaction stage following the hydroperoxide maximum. Soluble collagen was converted into insoluble forms by the reaction with oxidized lipids. Basic amino acids were blocked by reaction with oxidized lipids but the bonds formed became resistant to acid hydrolysis only in the stage following the hydroperoxide maximum. Changes of sensory profiles could be explained by reactions of flavour-active carbonylic oxidation products with protein.     

A Strategy for Rapid Mismatch Evaluation of Transient Characteristics of CMOS Analog Cells

A strategy is presented to evaluate the statistical means and standard deviations of the transient characteristics of CMOS analog cells. Based upon the Monte Carlo analysis of electrical simulations, this strategy follows a circuit-theory based approach achieving an important reduction on matrix ranges and consequently on the number of operations involved in the resolution of the circuit. The CPU time-consuming reduction is achieved also by saving information corresponding to the nominal transient analysis. We include comparative results for several CMOS cells showing the advantages of the proposed strategy.     

Integrated Inductors Modeling for Library Development and Layout Generation

In this work we propose a modification to the conventional lumped equivalent circuit model for integrated inductors. Also the widely used parametric model is modified. The proposed models expand the frequency range where the integrated inductor behavior is accurately predicted. They are useful in developing automatic tools to assist the designers in selecting and automatically laying-out integrated inductors [1]. This work is based on measurements from integrated inductors fabricated in a standard silicon process.     

Dosage individualization of erythropoietin using a profile-dependent support vector regression

The external administration of recombinant human erythropoietin is the chosen treatment for those patients with secondary anemia due to chronic renal failure in periodic hemodialysis. The objective of this paper is to carry out an individualized prediction of the EPO dosage to be administered to those patients. The high cost of this medication, its side-effects and the phenomenon of potential resistance which some individuals suffer all justify the need for a model which is capable of optimizing dosage individualization. A group of 110 patients and several patient factors were used to develop the models. The support vector regressor (SVR) is benchmarked with the classical multilayer perceptron (MLP) and the Autoregressive Conditional Heteroskedasticity (ARCH) model. We introduce a priori knowledge by relaxing or tightening the epsilon-insensitive region and the penalization parameter depending on the time period of the patients' follow-up. The so-called profile-dependent SVR (PD-SVR) improves results of the standard SVR method and the MLP. We perform sensitivity analysis on the MLP and inspect the distribution of the support vectors in the input and feature spaces in order to gain knowledge about the problem.     

碳纳米管的大面积合成及磁性(英文)

通过溶胶凝胶法和氢气还原法制备出Co纳米颗粒并以此作为催化剂材料,通过催化裂解苯的方法,实现了较低温度(460℃)下在Co纳米颗粒表面上合成碳纳米管。采用X射线衍射、激光喇曼光谱、场发射扫描电镜、透射电子显微镜和振动样品磁强计对所合成的碳纳米材料进行了表征。通过优化实验参数,可制备出最大产率和纯度分别为约50和98.02%(质量分数)的碳纳米管。由于铁磁性Co纳米颗粒的进入,使得整个复合物表现出比较好的磁性能。和以往以苯作为碳源合成碳纳米材料相比,此合成方案简单、成本低,且对环境无任何危害,非常适用于磁性碳纳米复合物的批量合成。     

Capacity of practical wireless multihop broadcast networks

In a wireless multihop broadcasting scenario, a number of relay nodes may cooperate the source node in order to improve the capacity of the network. However, the imposition of total energy and maximum hop constraints to this system in a practical setting. In this paper, we study an ad-hoc network with infinitely many nodes and analytically find the number and positions of rebroadcasting relay nodes to achieve the optimal broadcast capacity. The interference due to multiple transmissions in the same geographical area is taken into account. According to the results of this theoretical model, we propose two heuristics, one distributed and one centralized, as suboptimal but practical solutions to the relay selection problem in wireless multihop broadcasting. We discuss the broadcast capacity performances and CSI (channel state information) requirements of these algorithms. The results illustrate that the benefits of peer-assisted broadcasting are more pronounced in the centralized relay selection algorithm when compared to the fully randomized and distributed selection under a realistic system model.     

Hole boil-off and the magnetoresitance of the semimagnetic semiconductor Hg1−x MnxTe1−y Sey

Galvanomagnetic effects were investigated in gapless and narrow-gap semiconductors of the form Hg_1−x Mn_xTe_1−y Se_y with x=0.03–0.11, y=0.01–0.10 (−150<ɛ _g <190)meV and acceptor concentration 5.4×10¹⁶<N _A <4.3×10¹⁸ cm⁻³. In magnetic fields H=5–50 kOe and at T=1.3–4.2 K, the observed hole concentration p=1/eR was found to increase by a substantial factor (of up to 500). This was accompanied by a fall in the longitudinal (ρ _zz ) and transverse (ρ _xx ) magnetoresistivities. The hole “boil-off” is assumed to be a consequence of the existence at H=0 of a bound magnetic polaron and the delocalization of carriers when these states are destroyed by the external magnetic field. The anomalous ratio of longitudinal-to-transverse resistivities (ρ _zz >ρ _xx ), observed at liquid-helium temperatures and in magnetic fields H>10 kOe, is explained in terms of the properties of the energy spectrum of the valence band of semimagnetic semiconductors in quantizing magnetic fields. Fiz. Tekh. Poluprovodn. 31, 1198–1205 (October 1997)     

Thermal Effects of Microwave Energy in Agricultural Soil Radiation

The thermal treatment by millimeter waves for the soil disinfection can be one possible alternative to chemical treatments. This physical method is based on incrementing the soil temperature and its pathogens irradiating with high frequency electromagnetic waves. So the previous knowledge of the temperature distribution in the irradiated soil is essential for achieving an effective bad microorganism and weed seeds elimination. This report analyse the heating kinetic and spatial distribution of the maximum temperatures reached by the soil. It is presented a mathematic model about how are distributed the reached temperatures in the depth of the irradiated soil. This model concludes that when an orchard soil is irradiated superficially by microwaves, the microwaves have a big attenuation due to the soil dielectric properties and the water located in the pores of the most superficial layer. This fact causes a shield effect blocking the waves penetration in few centimetres. The heating by radiation is reduced to the superficial layer. The heating propagation in the depth is occurred by conduction following the Fourier equations.     

Transient negative photocurrent and out-of-well dipole kinetics in novel piezoelectric InGaAs/GaAs MQW pin diodes

In 111B InGaAs/GaAs pin structures with a multiple quantum well (MQW) embedded region, the average internal field in the active MQW region can be tailored to obtain device configurations with a negative average field (NAF), opposite to the built-in field. In 111 NAF diodes, carriers photogenerated at the wells become trapped early at the potential minima located at the ends of the active region thus creating an electric dipole. In this work, in 111 NAF devices with a 0.17 In mole fraction layers, by using time-resolved photocurrent and a novel optical-pump electrical-probe techniques, we report the presence of a negative transient photocurrent, a direct quantitative evidence of such dipole formation, and we present measurements of its extinction kinetics at room temperature.     

Study of the glucide fraction in ropy wines

Gas chromatography was used to study the polysaccharides present in samples that exhibited significant microbially induced viscosity values. Alterations in the media considered were related to the percentage glucose content and the total polysaccharide content.