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Simultaneous characteriz.tion of multiple properties of solid and liquid phases in crystalliz.tion processes using Nir

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Particuology 2011年第6期9卷 589-597页

作者： Chao Y. Ma Xue z. Wang Institute of Particle Science and Engineering School of Process Environmental and Materials Engineering University of Leeds Leeds LS2 9JT UK

Near infrared spectroscopy （Nir） is now probably the most popular process analytical technology （PAT） for pharmaceutical and some other industries. However, unlike mid-ir, Nir is known to have difficulties in monitoring crystalliz.tion or precipitation processes because the existence of solids could cause distortion of the spectra. This phenomenon, seen as unfavorable previously, is however an indication that Nir spectra contain rich information about both solids and liquids, giving the possibility of using the same instrument for multiple property characteriz.tion. In this study, transflectance Nir calibration data was obtained using solutions and slurries of varied solution concentration, particle siz., solid concentration and temperature. The data was used to build calibration models for prediction of the multiple properties of both phases. Predictive models were developed for this challenging application using an approach that combines genetic algorithm （GA） and support vector machine （SVM）. GA is used for wavelength selection and SVM for mode building. The new GA-SVM approach is shown to outperform other methods including GA-PLS （partial least squares） and traditional SVM. Nir is thus successfully applied to monitoring seeded and unseeded cooling crystalliz.tion processes of L-glutamic acid.

关键词： Process analytical technology Near infrared spectroscopy Support vector machine Genetic algorithm Wavelength selection Cooling crystalliz.tion

Concentrations of gastric mucosal cytokines in children with food allergy and Helicobacterpylori infection

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World Journal of Gastroenterology 2005年第43期11卷 6751-6756页

作者： el(z..)bieta Maciorkowska Anatol Panasiuk Maciej Kacz.arski Department of Pediatric Nursing Department of Infectious Diseases 3rd Department of Children's Diseases

AIM： To measure the concentrations of chosen cytokines in the antrum mucosa depending on the kind of harmful pathogenic factors and to compare the concentrations with the values of controls without allergy and coexisting Helicobacter pylori （H pylori） infection. METHODS： The patients （97 children） were divided into three groups according to the data obtained from the case history, to the main cause of the disease and to the dominant clinical symptoms. Group Ⅰ： children with food allergy （Fa）; group Ⅱ： children infected with H pylori; group Ⅲ （control group）： children with functional disorders of the alimentary tract （without Fa and Hp infection）. H pylori infection was determined by the presence of anti-Hp antibodies in serum （elIsa method） and urease test performed during endoscopic examination. Cytokine concentration in homogenates of gastric mucosa was detected by elIsa method. RESULTS： The IL-2 concentration in gastric mucosa bioptates was the highest in children with Hp infection （116.5±179.5 pg/mg of the protein） and Fa and Hp infection （98.1±101.0 pg/mg）, while decreased in children with Fa （44.8±50.3 pg/mg） and controls （45.7±23.5 pg/mg）. The lowest mean concentration of IFN-y was observed in children with Hp infection （18.9±16.4 pg/mg）, with Fa and Hp infection （25.5±27.7 pg/mg）, with Fa （40.6±39.7 pg/mg） and controls （49.9±33.4 pg/mg）. The highest IL-4 concentrations were observed in children with Hp infection （35.3±52.8 pg/mg） and in children with Fa and Hp infection （37.2±51.7 pg/mg）, while lower IL-4 concentration （23.64-35.8 pg/mg） was found in children with Fa compared to the controls （22.7±13.8 pg/mg）. The analysis of IL-4 concentrations in children with Hp infection regarding the intensity of gastritis showed the highest value （62.2±61.2 pg/mg） in mild and moderate gastritis. The concentrations of IL-5 in the gastric mucosa of children with or without Fa did not differ significantly and were comparable to the control group. The highest mean IL-8 val

关键词： Mucosal cytokines Food allergy Helicobacterpylori dehydrogenase complex

Development of controlled release formulations of thiabendaz.le

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Journal of Agricultural Chemistry and Environment 2014年第1期3卷 1-8页

作者： Yasser z. el-Nahhal Department of Earth and Environmental Science Faculty of Science The Islamic University-Gaza Gaza Palestine

This study aimed to develop controlled release formulation of Thiabendaz.le for reduced contaminations to soil water and agricultural produces. The idea behind this work was based on changing the ioniz.tion status of Thiabendaz.le molecule throughout pH changes to become a cation then adsorbing it to bentonite clay surfaces. Equilibrium concentrations of Thiabendaz.le in the adsorption solutions were determined by HPLC. Results showed that Thiabendaz.le was better adsorbed in clay at the lowest pH value (pH 3). Furthermore, raising the temperature of the adsorption reaction increased the adsorbed amount of Thiabendaz.le. Release experiments showed that Thiabendaz.le is extremely slower at pH 3 than at pH 5.5 or pH 9. These promising results suggest that application of Thiabendaz.le clay based formulation may reduce the applied rate and that the released fraction consequently may reduce the environmental contamination. It is also advantageous to use these formulations in the acidic soil for plant disease control.

关键词： Thiabendaz.le Adsorption Controlled Release pH Bentonite

Comparative study of three types of controllers for DFIG in wind energy conversion system

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Protection and Control of Modern Power Systems 2018年第1期3卷 223-234页

作者： saïd Boubz.z. Hafedh Abid Ahmed el hajjaji Mohamed Chaabane Lab-STA Laboratory National Engineering School of SfaxRoute de la Soukra3029 SfaxTunisia MIS Laboratory University of Picardie Jules Verne33Rue Saint-Leu80039 AmiensFrance

This paper presents an enhanced control strategy for Wind Energy Conversion System(WECS)using Doubly-Fed Induction Generator(DFIG).A robust Super-Twisting(STW)sliding mode control for variable speed wind turbine is developed to produce the optimal aerodynamic torque and improve the dynamic performance of the *** electromagnetic torque of the DFIG is directly tracked using the proposed control to achieve maximum power *** performance and the effectiveness of the STW control strategy are compared to conventional Sliding Mode(SM)and Proportional-Integral(PI)*** proposed STW algorithm shows interesting features in terms of chattering reduction,finite convergence time and robustness against parameters variations and system disturbances.

关键词： Wind turbine(WT) Doubly-fed induction generator(DFIG) Power generation STW(super-twisting) Second order sliding mode control(SOSMC) PI controller

electrooxidation of methanol and ethanol on carbon electrodeposited Ni–MgO nanocomposite

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Chinese Journal of Catalysis 2016年第4期37卷 616-627页

作者： H. B. Hassana z. Abdel Hamid Rabab M. el-Sherif 开罗大学理学院化学系埃及吉萨冲央冶金研究开发研究所埃及开罗

Ni–MgO nano‐composites were prepared on carbon anodes by electrodeposition from a nickel Watts bath in the presence of fine MgO reinforcement particles. Their performance as electrocata‐lysts for the oxidation of methanol and ethanol in alkaline medium was investigated and compared with that of carbon coated pure Ni （Ni/C）. The chemical composition, phase structure, and surface morphology of the deposited nano‐composites were studied by energy dispersive X‐ray spectros‐copy, X‐ray diffractometry, and scanning electron microscopy, respectively. Different electrochemi‐cal techniques were used to estimate the catalytic activity of the prepared electrocatalyst anodes, including cyclic voltammetry （CV）, chronoamperometry, and electrochemical impedance spectros‐copy （EIS）. The Ni/C electrocatalyst alone exhibited remarkably low catalytic activity and poor stability toward the electrooxidation process. The inclusion of MgO significantly promoted the cata‐lytic activity of the Ni catalyst for the alcohol electrooxidation and enhanced its poisoning re‐sistance. The EIS results confirmed those of CV and revealed a lower charge transfer resistance and enhanced roughness for the Ni–MgO/C nano‐composite electrodes compared with those of Ni/C.

关键词： Nickel-modified manganese oxide electrooxidation Methanol Ethanol electrochemical impedance spectroscopy Cyclic voltammetry

Estimation of Photoelectrocatalytic Activity of Titanium Oxide Film electrodes by Ac Impedance

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Chinese Chemical Letters 2001年第11期12卷 1019-1022页

作者： Leng, WH z.ang, z.Cheng, sa z.ang, JQ Cao, CN z.ejiang Univ Dept Chem Hangzhou 310027 Peoples R China

In this paper, we demonstrated that the charge-transfer resistance of photoanode can be calculated through the analysis of its electrochemical impedance spectroscopy (EIS) and the photoelectrocatalytic degradation rate of aniline was inversely proportional to the value of charge-transfer resistance of photoelectrodes prepared by thermally oxidation on titanium. The value of charge-transfer resistance is smaller, the higher its photoelectro-activity is.

关键词： photoactivity charge-transfer resistance titanium dioxide impedance

The effect of caloric restriction on genetical pathways

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Food Science and Human Wellness 2023年第5期12卷 1450-1457页

作者： Mustafa Fevz. Karagöz.A.Gülçin sağdıçoğlu Celep Faculty of Health Sciences Department of Nutrition and DieteticsGazi UniversityÇankaya 06490Turkey

Energy restriction is defined as reducing nutrient intake without dragging the organism into malnutrition. Energy restriction is preferred because it is a non-genetic intervention that increases life expectancy. Nicotinamide adenine dinucleotide(NAD~+)and adenosine monophosphate(AMP)levels, which are the indicators of intracellular energy deficiency, increase with energy restriction. The increase in NAD~+ level stimulates sirtuin(SirT)enz.mes, and the increase in AMP level stimulates AMP-activated protein kinase(AMPK). Various mechanisms are regulated by stimulating these enz.mes. By Forkhead box O(FoxO)transcription factors, the ability of resistance to oxidative stress increases, and antioxidant genes, DNA repair, and autophagy genes are stimulated. Apoptosis is induced by stimulation of the p53 protein, and tumor growth is suppressed by the disruption of aging cells. The suppression of phosphoinositide 3-kinase(PI3K)-/-Akt, and therefore mTOR signal stimulates autophagy and mitophagia, and cleanses damaged cells and organelles. Mitochondrial biogenesis is stimulated, antioxidant capacity increases, and inflammatory response decreases. Adipose tissue and lipid metabolism are regulated by the regulation of fatty acid synthesis and oxidation. As a consequence, the effects of caloric restriction on cellular metabolism are regulated through the genetic pathways.

关键词： Caloric restriction Energy restriction Sirtuin AMPK Mitochondrial biogenesis

Effect of Film Thickness on the Optical Parameters and electrical Conductivity of Te_(10)Ge_(10)Se_(77)Sb_3 Chalcogenide Glass

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Journal of Materials Science & Technology 2003年第1期19卷 36-40页

作者： z.el-Gohary A.Abdel-Al 等 PhysicsDepartment FacultyofScienceMenoufiaUniversityShebinEl-KoomEgypt PhysicsDepartment FacultyofScienceHelwanUniveristyCairoEgypt

Several thin films of Te10Ge10Se77Sb3 chalcogenide glass of different thicknesses (250 nm to 400 nm) were prepared by thermalevaporation under vacuum of 133×10-6 Pa (10-6torr). X- ray diffraction analysis showed the amorphicity of the preparedfilms which become partially crystalline by annealing. Transmittance and reflectance measurements in the spectral range of200 nm to 2500 nm have been carried out at normal incidence. The analysis of the absorption coefficient data showed theexistence of indirect transition for the photon energy E in the range 1~3 eV and direct transition for E >3 eV. From thedetermination of the optical constants (n, k), the dispersion of the refractive index has anomalous behaviour in the region ofthe fundamental absorption edge, and followed by the single- effective oscillator *** investigated optical parameterssuch as the optical energy gap Eopt, the high frequency dielectric constant εoo, the oscillator position λo, and the oscillatorstrength So, were significantly affected by the film thickness. The characteristic energy gap obtained from the conductivitymeasurements is nearly half the value of that obtained from the optical data as in the case of thickness 400 nm. The activationenergy is 0.65 eV and the indirect optical gap is 1.32 eV.

关键词： Chalcogenide glasses Optical properties Conductivity

Effect of Pb Ions on the Ionic Conductivity of Some Silicate Glass Systems

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Journal of Materials Science & Technology 2002年第5期18卷 391-394页

作者： A.G.Mostafa z.A.el-Hadi 等 PhysicsDepartment FacultyofScienceAl-AzharUniversityNasrCityCairoEgypt ChemistryDepartment UniversityCollegeforGirlsAinShamsUniversityCairoEgypt

Conductivity of glasses in the systems ***, (where R=Ca, Sr or Ba) was investigated between room temperature and 530 K. The dependence of log resistivity as well as the activation energy on the PbO content has been studied. Based on the present experimental results, the possible different conduction mechanisms in such glasses are discussed. It was postulated that Pb2+ ions may represent the major charge carrying species in these glasses. This assumption was confirmed by the calculations of the mean distance between the interstitial Pb2+ ions and the effective center of the O2- ions in the glass networks. The variation in the values of the density and the molar volume with PbO content is also discussed in view of the obtained activation energies for the studied glass-systems.

关键词： Ionic conductivity Pb ion Silicate glass systems