Effects of Food Diet Preparation Techniques on Radionuclide Intake and Its Implications for Individual Ingestion Effective Dose in Abeokuta, Southwestern Nigeria

The radioactivity measurements in food crops and their diet derivatives and farm soil samples from Abeokuta, one of the elevated background radiation areas in Nigeria have been carried out in order to determine the concentration levels of natural radionuclides (40K, 226Ra and 232Th). The activity concentrations of the natural radionuclides in the samples were determined via gamma-ray spectrometry using a 76 mm × 76 mm NaI(Tl) detector. Different common food crops representing the major sources of dietary requirements to the local population were collected for the measurements. The collected food crops were prepared into their different derivable composite diets using preparation techniques locale to the population. Using available food consumption data and the activity concentrations of the radionuclides, the ingestion effective doses were evaluated for the food crops and diet types per preparation techniques. For the tuberous food crop samples, the annual ingestion effective doses in the raw and different composite diets were 0.02 - 0.04 μSv and cumulatively 0.04 - 0.05 μSv while in the non-tuberous crops the doses were 0.44 - 0.70 μSv and cumulatively greater than 1 μSv respectively. Results of the study indicate that method of diet preparation is seen to play a major role in population ingestion dose reduction especially for tuberous crops than in non-tuberous crops. The study also showed that more ingestion dose could be incurred in diets prepared by roasting techniques. The result of the study will serve as a useful radiometric data for future epidemiological studies in the area and for food safety regulations and policy implementations in the country.

Preparation technique of SiCp reinforced Al matrix composite

A new preparation technique-"block dispersal and cast" method is introduced, and three kinds of powder mixing methods, vertical, horizontal and inclining styles, are compared. The results demonstrate that the inclining style is the best way to mix powders. The Al and nano SiC powders are pressed into blocks, dipped into molten Al, stirred into mold so that SiC/Al matrix composites can be obtained at last. The microstructure of SiC particle reinforced Al matrix composite prepared by "block dispersal and cast" method have been studied using scanning electron microscopy (SEM). Phase analysis has also been conducted by means of X-ray diffraction (XRD). The results show that nano SiC particles can be dispersed uniformly in Al matrix. Thus, it is feasible to prepare SiC particle reinforced Al matrix composites by this method.

Effect of Preparation Techniques of Y-Mo/HZSM-5 on Its Activity in Methane Aromatization

The production of benzene directly from methane aromatization under oxygen-free condition is currently a new focus in natural gas utilization. The influence of preparation techniques of the catalysts on their catalytic activities is studied in this paper. The influencing factors include the impregnating method, the calcination temperature, the promoter content and the acidity of the zeolite support. Optimum preparation techniques for the catalysts are obtained through this work.

Review on preparation techniques of particle reinforced metal matrix composites

This paper reviews the investigation status of the techniques for preparation of metal matrix composites and the research outcomes achieved recently. The mechanisms, characteristics, application ranges and levels of development of these preparation techniques are analyzed. The advantages and the disadvantages of each technique are synthetically evaluated. Lastly, the future directions of research and the prospects for the preparation techniques of metal matrix composites are forecasted.

A supercritical CO_2 fluid technique for the preparation and evaluation of rhBMP-2-loaded PLLA microspheres

Introduction The use of supercritical fluids such as supercritical CO2（scCO2） has provided a ’clean’ and effective alternative to traditional methods of protein delivery systems.Here。

Liquid phase separating mechanism and preparation techniques of immiscible alloys

Immiscible alloys have attracted growing interest for their valuable physical and mechanical properties. However, their production is difficult because of metallurgical problems in which there is a serious tendency for gravity separation in the region of the miscibility gap. So far the study on the liquid separation mechanism is still one of the important projects in the spatial materials science and the spatial fluid science. The studied results about the liquid phase separating mechanism of immiscible alloys are presented, at the same time the preparation techniques of homogeneous immiscible alloys are summarized, and the existing problems and the related researching areas in the future are also pointed out.

High Thermoelectric Figure of Merit of Ag8SnS6 Component Prepared by Electrodeposition Technique

A new thermoelectric material Ag8SnS6, with ultra-low thermal conductivity in thin film shape, is prepared on indium tin oxide coated g/ass （ITO） substrates using a chemical process via the electrodeposition technique. The structural, thermal and electrical properties are studied and presented in detail, which demonstrate that the material is of semiconductor type, orthorhombic structure, with a band gap in the order of 1.56eV and a free carrier concentration of 1.46 × 10^17 cm-3. The thermal conductivity, thermal diffusivity, thermal conduction mode, Seebeck coefficient and electrical conductivity are determined using the photo-thermal deflection technique combined with the Boltzmann transport theory and Cahill＇s model, showing that the AgsSnS6 material has a low thermal conductivity of 3.8 Wm - 1K- 1, high electrical conductivity of 2.4 × 10^5 Sm- 1, Seebeck coefficient of -180μVK-1 and a power factor of 6.9mWK-2m-1, implying that it is more efficient than those obtained in recently experimental investigations for thermoelectric devices.

A Comparison of Techniques for Preparing Somatic Chromosomes in Ribes Species

Ribes plants,like most of other fruit trees,are characterized by their large number but small size of somatic chromosomes.In the light of these special characteristics,we have examined several factorial combinations of material, pretreatment,slide preparing method and stain to identify the most promising techique for studying the chromosomes and further analyzing the karyotypes and chromosome banding of Ribes plants. The resuts indicated that the combination of root tip with pretreatment of 2 m molL-1 8-hydroxyquinoline plus 0.05% colchicine or 0.3% balm for 3～5 hours at 14℃,pre-hypotonic trcarment of 0.07mol L-1 KCl for 30 min, fixation in Carnoy's fluid,hydrolysis in 5% cellulase and 5% pectinase mixture for 4～5 hours at 25℃, post-hypotonic treatment in distilled water for half an hour and staining in Giemsa could make the chromosome prepa ration superior to other treatment combinations.

Research Progress on Analysis and Detection Techniques of Veterinary Drug Residues in Animal Foods

As an important guarantee for the prevention and control of animal diseases,veterinary drugs have important functions in improving animal production performance and product quality and maintaining ecological balance.They are an important guarantee for the healthy development of animal husbandry,food safety and public health.However,the irrational use and abuse of veterinary drugs and feed pharmaceutical additives are widespread,causing harmful substances in animal foods and damage to human health,and threatening the sustainable development of the environment and animal husbandry as well.In order to ensure human health,it is urgent to develop a simple,rapid,high-sensitivity,high-throughput and low-cost veterinary drug residue detection technology.In this paper,the sample pretreatment methods and detection techniques for the analysis of veterinary drug residues in animal foods were reviewed.

Preparation and Characterization of Ordered Ladder Like Polyphenylsilsesquioxane via Two-step Sol-gel Method

Soluble and ordered ladder like polyphenylsilsesquioxane was synthesized by a two-step sol-gel method including hydrolysis and polycondensation. The procedure was monitored by Fourier transform infrared spectroscopy and the presence of the ladder like structure was confirmed by X-ray techniques. 29Si NMR analysis shows a very narrow half peak width（δ4） at δ –78.866 of the main chain unit C6H5SiO3/2 of polyphenylsilsesquioxane, indicating that the polyphenylsilsesquioxane has ordered ladder like structures rather than the branched ones. The relationship between molecular weight and the time of polycondensation was also discussed.

Scalable preparation and direct visualization of cyclic polymers via self-folding cyclization technique

Cyclic polymers exhibit distinct properties compared with their linear counterparts due to the lack of chain ends.However,the scalable synthesis of cyclic polymers remains a major challenge,especially for ring-closure method.Herein,we report a novel strategy for large-scale preparation of cyclic polymers,which relies on the prior self-folding of anthracene-telechelic amphiphilic random copolymers(poly((oligo(ethylene glycol)acrylate)-co-(dodecyl acrylate)),P(OEGA-co-DDA))into single-chain polymeric nanoparticles(SCPNs)in water.Subsequent ultraviolet(UV)-induced cyclization occurs in the hydrophobic nano-domain.The formation of SCPNs leads to a shortened distance between the end groups of the linear precursors and spatially separated cyclization loci,and significantly enhances the efficiency of UV-induced cyclization.This self-folding technique permits access to the synthesis of cyclic polymers not only with high molecular weights(M_(n)>10^(5) g/mol),but also in a decent scale(40 g/L),breaking through the limitations of ring-closure method.Furthermore,the dense pendants of the copolymers can magnify the macromolecules by increasing the mass density along the backbones,thus making the polymers more readily detectable by the microscopy.The transmission electron microscopy(TEM)and atomic force microscopy(AFM)images allow us to observe the topological structures directly and provide crucial evidence to confirm the cyclization.

Influences of preparation techniques on glass-forming ability of Fe-P-B-Si-C amorphous alloys

It has been widely accepted that the ultrafast cooling rate is required for the glass formation of amorphous alloys. Here, the larger glass-forming ability （GFA） of Fe76P5（B0.5Si0.3C0.2）19 amorphous alloy was achieved by water quenching at lower cooling rate under argon atmosphere. Cylindrical rods with diameters of 1-2 mm were prepared by water quenching without flux treatment, Cu-mold injection casting, and Cu-mold suction casting, respectively. The influences of the preparation techniques with different cooling rates on GFA, thermal property, and nucleation/growth behavior were examined. The critical diameter of the Fe76P5（B0.5Si0.3C0.2）19 amorphous alloys is 1.7 mm for water quenching while smaller than 1.0 mm for injection casting. Microstructure analysis indicates that the crystallization and solidification processes are quite different between the water-quenched and the injection-cast rods. These findings could deepen fun-damental understanding on the relationship between the cooling rate, techniques, and GFA of Fe-based amorphous alloys.

Preparation and laser properties of Yb^3＋-doped microstructure fiber based on hydrolysis-melting technique

The Yb^(3+)-doped silica glass was prepared by the Si Cl_4 hydrolysis doping and powder melting technology based on high frequency plasma. The absorption and emission characteristics of the Yb^(3+)-doped silica glass are studied at room temperature. The integrated absorption cross section,stimulated emission cross section and fluorescence lifetime are calculated to be 8.56×10~4 pm^3,1.39 pm^2 and 0.56 ms,respectively. The Yb^(3+)-doped microstructure fiber(MSF) was also fabricated by using the Yb^(3+)-doped silica glass as fiber core. What's more,the laser properties of the Yb^(3+)-doped MSF are studied.

蕲艾油-β-环糊精包合物膜剂的制备及工艺优化

为了提高挥发油在制剂中的生物利用度,采用β-环糊精对挥发油进行包合,再以羧甲基纤维素钠作为成膜材料,考察蕲艾油-β-环糊精包合物膜的最佳工艺.用饱和水溶液法制备蕲艾油-β-环糊精包合物,以外观评价、膜性质、脱模性能和贴肤度作为表征评价指标,通过正交试验考察蕲艾油用量、β-环糊精用量、羧甲基纤维素钠浓度以及甘油用量对成膜工艺的影响.结果:蕲艾油-β-环糊精包合物膜最佳成膜工艺为:蕲艾油用量为1.5 mL、β-环糊精用量为10 g、羧甲基纤维素钠∶去离子水为1∶20(W/V,g·mL^(-1))、甘油用量为6 mL,用去离子水定容至100 mL.结论:优选得到的成膜工艺简单、稳定、可行,为该剂型的后续开发奠定基础.

逍遥散方质量控制技术研究进展

逍遥散方为治疗妇科诸疾、郁证的代表方,由柴胡、当归、茯苓、白芍、白术、甘草、生姜、薄荷8味饮片组成,具有疏肝解郁、养血健脾的功效。文章就近10年来逍遥散方在制备工艺、鉴别技术、含有量测定等方面出现的新方法、新技术进行归纳总结,以期为该方制剂的质量控制及进一步开发应用提供科学依据。

WC-Ni基硬质合金的基础研究进展

WC-Ni基硬质合金可应用在磁性材料成形模具和核主泵机械密封关键部件等极端工况领域。由于材料体系的本征特性,WC-Ni基硬质合金的高性能化和质量稳定性控制一直面临挑战。两相区碳窗口、固液转变温度、液相烧结过程中的润湿行为,以及合金组元在黏结相中的固溶特性,是硬质复合材料成分及其制备工艺设计的关键参数。本文以制备工艺体系最完善的WC-Co基硬质合金为参比对象,从上述4个方面对WC-Ni基硬质合金的本征特性及其研究进展进行综述,旨在强化对WC-Ni基硬质合金本征特性的理解,为高性能WC-Ni基硬质合金新材料高效开发提供参考。

冠状动脉钙化病变预处理手段的研究进展

冠状动脉钙化病变发病率高,并发症多,是介入医师面临的重大挑战之一。钙化病变限制支架的定位与扩张,导致支架置入失败或扩张、贴壁不良等围术期并发症,同时与远期靶血管失败相关。消蚀技术或球囊技术的发展使得钙化病变的预处理效果较前改善。但是,这些预处理手段仍受到深层钙化、完全闭塞等钙化特点的限制。近些年预处理技术的进展使得上述限制得到缓解。半程冠状动脉斑块旋磨术的策略减低了操作相关的并发症发生率,准分子激光冠状动脉斑块消蚀术在复杂钙化病变中的应用证据不断积累,以及近些年应用于临床的冠状动脉血管内碎石术,表现出在深层钙化病变中的应用优势。本文围绕钙化病变预处理技术的进展进行综述,并对预处理手段的选择提出建议,旨在指导临床策略的选择,改善患者预后。

生物导向型预备技术在口腔修复中的应用

口腔修复中的牙体预备边缘一直是口腔医生关注的热点问题,不当的预备边缘可能导致龋病和牙周炎等疾病,最终导致修复失败。生物导向型预备技术的应用已证明可恢复良好的牙周软硬组织形态,有望替代传统牙体预备方法。从生物导向型预备技术在贴面、全冠、种植中的应用综合论述生物导向型预备技术在口腔修复中的应用。

AgCu系电接触材料研究进展

银铜系电接触材料作为银基电接触材料的一大重要门类在电接触材料行业中因其卓越的电导率、耐磨性、抗熔焊性和广泛应用而占据重要地位。本文对Ag CuNi、AgCuV、AgCuO合金系列以及Ag Cu/LSCO等银铜系电接触材料的性能特点、制备工艺和研究现状进行了归纳和阐述。分析了银铜系电接触材料研究中存在的问题,并展望了发展趋势。

硫酸软骨素钠的制备及抗骨关节炎活性研究进展

硫酸软骨素钠是一种硫酸化的糖胺聚糖,由D-葡萄糖醛酸和N-乙酰-D-氨基半乳糖的重复双糖单位组成。硫酸软骨素钠的工业生产是以陆地生物或海洋生物软骨组织为原料,经过特定的提取和纯化工艺制得,被认为具有抗骨关节炎及其他多种潜在的生理活性,在保健食品、化妆品、药品等领域具有广阔的应用前景和发展空间。该文对硫酸软骨素钠的传统制备技术、微生物合成工艺的开发情况与问题,以及基于体外细胞、动物模型和临床随机对照试验的抗骨关节炎活性研究现状进行综述,分析了现阶段研究的局限性并提出相应对策,为进一步规范和开发硫酸软骨素钠提供参考。