Analysing of <Superscript>228</Superscript>Th, <Superscript>232</Superscript>Th, <Superscript>228</Superscript>Ra in human bone tissues for the purpose of determining the post mortal interval

The adsorption of Cs on clayey materials such as bentonite and Na-montmorillonite was studied in various electrolytic conditions (concentration and composition), various solid to liquid ratios and various pH conditions. The results obtained for these different conditions were modeled considering an exchange model associated to the surface complexation concept. Then, the same approach was considered to model the sorption of Rb, which have the same chemical behavior than Cs. Experiments were carried out for various electrolyte, pH, and Rb concentrations. The stoichiometries corresponding to the sorption of Rb on bentonite and montmorillonite were then deduced from the experimental results.     

Kinetics of thermal decomposition of CuSO4 · 5H2O to CuO

The effect of particle size, type of crucible, and heating rate on the thermal curves obtained simultaneously for CuSO₄ · 5H₂O were discussed. The dissociation steps were confirmed. Thermogravimetric techniques for determining the rate-controlling processes and kinetic parameters were applied for the dehydration steps and the calcination of CuSO₄ and CuSO₄ · CuO. For the dehydration of the monohydrate one mechanism operates but the activation energy and preexponential factor vary over wide ranges. Differentiating between various mechanisms using the same technique was sometimes difficult giving completely different values for the kinetic parameters. In view of such difficulties the various methods were assessed, the best techniques to treat similar results were recommended and the operating mechanisms and kinetic parameters for the various steps were thus established.     

Adsorption and interface accumulation of aquasol and organosol carbon particles labeled with99mTc

Aerosol particles of^99mTc-labeled carbon were prepared by sublimation and introduced in various liquid media. The adsorption of the aquasol and organosol particles were studied for various adsorbing substances and media, with the effect of surface treatment and voltage application. The particles often accumulated at the aqueous-organic interface, and also on the vessel surface in the presence of both aqueous and organic phases. The distribution of the particles was examined by a gamma-camera for different organic phases under various concentrations of electrolytes in the aqueous phase.     

HPLC法测定辣椒油中苏丹红染料的测量不确定度评定

建立了HPLC法分析辣椒油中苏丹红染料的不确定度模型,分析了方法中的不确定度分量及其来源,计算了各不确定度分量和合成标准不确定度。     

Study of the effect of ionization conditions on the mass selective distributions of the ion mobilities of trotyl and hexogen by ion mobility spectrometry-tandem mass spectrometry

The results of a study of the ionization of trotyl and hexogen under atmospheric pressure and various environmental conditions were presented. The influence of environmental factors on the efficiency of the detection of explosives by ion mobility spectrometry was discussed. The peculiarities of ion mobility distribution and the formation of ion mobility spectra for the explosives under various ionization conditions were considered.     

Hydrophilic Characteristics of Cellulose Treated with Saturated Water Vapor

The reaction of water with cellulose treated with saturated water vapor at various temperatures for various times was studied. Trends in variation of its sorption and hydrophilic characteristics were examined.     

Rheological properties of aqueous solutions of polyethylene glycols with various molecular weights

The dependences of the kinematic viscosity of dilute aqueous solutions of polyethylene glycols (PEGs) with various molecular weights in the temperature range of 293.15–323.15 K were investigated. The intrinsic viscosity, the Huggins constant, and the activation energy of a viscous flow were calculated for these solutions. Proposals regarding the structure of polymer macromolecules in solution are made. The constants of the Mark-Kuhn-Hauvink equation required to estimate the polymer molecular weights were determined for PEG-water systems at various temperatures.     

Development and characterization of eucalyptol microemulsions for topic delivery of curcumin

Microemulsions have received great attention for applications in transdermal drug delivery. The use of curcumin for treating various skin diseases like scleroderma, psoriasis, and skin cancer was extensively reported. The solubility of curcumin in various oils, surfactants, and cosurfactants was studied herein in order to find the optimal components for a transdermal delivery vehicle. Microemulsion systems composed of eucalyptol, polysorbate 80, ethanol, and water were developed as transdermal delivery vehicles for curcumin. Effects of the microemulsion composition on transdermal curcumin delivery were studied using Franz diffusion cells. The transdermal curcumin flux, permeability coefficient, and enhancement ratio were analyzed to evaluate the effects of eucalyptol/water ratios in the microemulsions. Pseudo-ternary phase diagrams of the eucalyptol microemulsions with various surfactant/cosurfactant ratios (1:1-1:3) were constructed to investigate their phase behaviors. Conductivity, interfacial tension, size, and viscosity data of the microemulsions were used to characterize the physicochemical properties of transdermal vehicles. The influence of the microemulsions on skin histology and on the delivery route was analyzed using hematoxylin/eosin staining and confocal laser scanning microscopy. In conclusion, microemulsions were successfully developed for transdermal curcumin delivery after screening various components and adjusting the oil/water ratios. The curcumin permeation rate of the microemulsion developed was 15.7-fold higher than that of the control (eucalyptol only). These results indicate that an eucalyptol microemulsion system is a promising tool for the percutaneous delivery of curcumin.     

Silica-based xerogels modified with cobalt(III): Determination of naphthols in solutions by solid-phase spectrophotometry

Silica-based xerogels modified with various concentrations of cobalt ions were prepared. The redox and complexing properties of immobilized cobalt ions were studied. Modified xerogels were used for determining naphthols in solutions by solid-phase spectrophotometry after their nitrosation. The effects of various factors on the absorbance of xerogels were studied. These factors are the average pore diameter in powdered xerogels, the concentration of cobalt(III), the pH of the test solution, and the concentration of CH₃COOH and NaNO₂ at the stage of nitrosation. The best conditions for determining naphthols were found. The developed procedure was used in the analysis of various samples.     

Synthesis and cytotoxicity study of pyrazoline derivatives of methoxy substituted naphthyl chalcones

2-Acetyl naphthalene reacts with various methoxy substituted benzaldehyde in the presence of 10 % sodium hydroxide solution giving functionalized chalcones. The synthesized chalcones when further reacted with hydrazine hydrate in the presence of acetic acid afforded N-acetyl pyrazolines. All the synthesized products were confirmed by various spectral data such as FTIR, ¹H NMR, ¹³C NMR, and HRMS studies. All the synthesized compounds were screened for cytotoxicity against various cell lines.     

Biosorption of As3+ Ions Using Ternary Microspheres of Chitosan,Yeast, and Gelatin: A Dynamic and Equilibrium Investigation

Ternary biopolymeric microspheres of chitosan, yeast and gelatin were prepared and characterized by FTIR spectral analysis, particle size measurements, and scanning electron micrograph techniques. The prepared microspheres were investigated for static and dynamic studies of adsorption of As⁺³ ions onto the microspheres surfaces at fixed pH and ionic strength of the aqueous solution.The adsorption data were applied to Langmuir and Freundlich isotherm equations and various static parameters were calculated. The dynamic nature of adsorption was quantified in terms of several kinetic constants such as rate constants for adsorption, Lagergreen rate constant, inter particle diffusion rate constant and pore diffusion coefficient. The influence of various experimental parameters such as solid to liquid ratio, pH, temperature, and chemical composition of biopolymeric microspheres were investigated on the adsorption of arsenic ion and various thermodynamic parameter were also calculated.     

Surface modification of natural cellulose substances:toward functional materials and applications

Combining various synthetic chemical processes and biological assemblies provides a promising strategy for the design and fabrication of functional materials with tailored structures and properties.The unique multilevel structures and morphologies of natural cellulose substances such as ordinary commercial laboratory filter paper make them ideal platforms for the self-assemblies of various functional guest molecules that are to be deposited on the surfaces of their fine structures,and the resulting composite matters show significant potentials for various applications.The surface sol-gel process was employed to deposit ultrathin metal-oxide(e.g.,titania and zirconia)gel films to coat the cellulose nanofibers in bulk filter papers;thereafter,monolayers of specific guest substrates were immobilized onto the surfaces of the metal-oxide gel films.Highly selective,sensitive,and reversible chemosensors based on the surface modification of filter paper were obtained toward the fluorescence and colorimetric detection of various analytes such as heavy-metal ions,inorganic anions,amino acids,and gases.Cellulosebased composite materials with superhydrophobic,antibacterial,or luminescent properties were fabricated by self-assembly approaches toward practical applications.     

Effect of transient acid diffusion on pretreatment/hydrolysis of hardwood hemicellulose

Diffusivities of sulfuric acid in Aspen wood were experimentally determined at various diffusional temperatures and fitted to Arrhenius equations. These equations were subsequently incorporated into a theoretical model to establish the effect of transient acid concentration gradients within a solid substrate during acid-catalyzed hydrolysis of hemicellulose. Total xylose yield was found to decrease for increasing chip size, and this effect was intensified by increasing reaction temperature. Quantitative criteria were established for assessment of transient acid concentration effects upon xylose yield and reaction time at various reaction conditions.

     

Characteristics of Lipids from Individual Organs of Veronica beccabunga

Lipids from various organs of the aquatic plant Veronica beccabunga were studied. It has been demonstrated that neutral and polar lipids are qualitatively typical of higher photosynthetic plants. Lipids in various organs of aquatic veronica were unevenly distributed. The most significant differences were observed in neutral lipids for the accumulation of glycerin esters, free fatty acids, alcohols, and hydrocarbons. The ratio of phospholipids varied considerably in the polar lipids.     

Surfactantless synthesis of multiple shapes of gold nanostructures and their shape-dependent SERS spectroscopy

A useful method for the synthesis of various gold nanostructures is presented. The results demonstrated that flowerlike nanoparticle arrays, nanowire networks, nanosheets, and nanoflowers were obtained on the solid substrate under different experimental conditions. In addition, surface-enhanced Raman scattering (SERS) spectra of 4-aminothiophenol (4-ATP) on the as-prepared gold nanostructures of various shapes were measured, and their shape-dependent properties were evaluated. The intensity of the SERS signal was the smallest for the gold nanosheets, and the flowerlike nanoparticle arrays gave the strongest SERS signals.     

电解质对纳米银胶水溶液光谱行为的影响

纳米粒子因为具有量子尺寸效应和表面效应等特性而显示出体相材料不具备的各种性质[1] .贵金属纳米材料因其特有的光电磁性质、催化特性以及在微电子学领域中的潜在应用前景而成为纳米材料科学领域中的热点之一 [2～ 4 ] .纳米银胶粒子的表面性质对材料的性质和应用具有重要影响 .常用谱学手段研究纳米银胶的表面特性[5～ 7] .纳米银胶颗粒表面电子云的等离子体共振效应导致了银胶在紫外 -可见光谱上的特征吸收 ,而且吸收峰的峰形会受纳米银胶粒子的大小、分散溶剂及表面吸附分子等因素的影响 [8,9] .Arnim Henglein等 [9～ 11]系统研究了…     

荧光法研究不同离子对溶菌酶的猝灭作用

本文利用荧光法,在生理pH(7.37±0.02)条件下,分别测定了Fe3+、Cu2+、Ni2+、Co2+、NO2-、I-、盐酸胍对溶菌酶的猝灭作用。用荧光猝灭法求得不同猝灭剂对溶菌酶的猝灭常数KSV、生成常数KA、离解常数KD、结合位点数n和热力学参数ΔrGmΘ、ΔrHmΘ、ΔrSmΘ。据此判断了体系中猝灭剂对溶菌酶的作用机理。I-对溶菌酶的猝灭是动态猝灭,而Fe3+、Cu2+、NO2-Ni2+、Co2+及盐酸胍对溶菌酶是静态猝灭;Fe3+、Cu2+、Ni2+、Co2+与溶菌酶之间的作用力主要为氢键、范德华力;NO2-与溶菌酶间的作用力主要为静电作用力;I-与溶菌酶之间的作用力主要为疏水作用力。在分子水平上理解这些外源性化合物与溶菌酶的作用机理具有及其重要意义。     

Chlorodinitrophenylhydrazine, a useful crystalline agent for absolute configuration determination of various chiral ketones

For the determination of absolute configuration of various chiral ketones, we examined some hydrazines having a heavy atom as crystalline auxiliaries, and found that 2-chloro-4,6-dinitrophenylhydrazine is a useful crystalline agent for carbonyl compounds. Chiral hydrazones prepared from the hydrazine and various chiral ketones gave suitable single crystals for X-ray crystallographic analysis. The absolute configurations of the hydrazones were determined by X-ray crystallographic analysis using anomalous dispersion effect of the chlorine atom. The hydrazine is a useful crystalline agent for absolute configuration determination of various chiral ketones.     

Radiation-induced decoloration of oxazine in ethanolic solution

The decoloration yield of oxazine 720 in ethanolic solution was studied as a function of dose rate and concentration of the dye. Linear response for G values to a dose of 1.68 KGy was observed for various dye concentrations. The effect of various organic substances in the radiolysis of the dye was studied and the results were interpreted in terms of scavenging reactions.     

Comparison of simultaneous distillation extraction and solid-phase microextraction for the determination of volatile flavor components

Traditional simultaneous distillation extraction (SDE) and solid-phase microextraction (SPME) techniques were compared for their effectiveness in the extraction of volatile flavor compounds from various mustard paste samples. Each method was used to evaluate the responses of some analytes from real samples and calibration standards in order to provide sensitivity comparisons between the two techniques. Experimental results showed traditional SDE lacked the sensitivity needed to evaluate certain flavor volatiles, such as 1,2-propanediol. Dramatic improvements in the extraction ability of the SPME fibers over the traditional SDE method were noted. Different SPME fibers were investigated to determine the selectivity of the various fibers to the different flavor compounds present in the mustard paste samples. Parameters that might affect the SPME, such as the duration of absorption and desorption, temperature of extraction, and the polarity and structure of the fiber were investigated. Of the various fibers investigated, the PDMS–DVB fiber proved to be the most desirable for these analytes.