Determination of the design space of the HPLC analysis of water‐soluble vitamins

Analysis of water‐soluble vitamins has been tremendously approached through the last decades. A multitude of HPLC methods have been reported with a variety of advantages/shortcomings, yet, the design space of HPLC analysis of these vitamins was not defined in any of these reports. As per the food and drug administration (FDA), implementing the quality by design approach for the analysis of commercially available mixtures is hypothesized to enhance the pharmaceutical industry via facilitating the process of analytical method development and approval. This work illustrates a multifactorial optimization of three measured plus seven calculated influential HPLC parameters on the analysis of a mixture containing seven common water‐soluble vitamins (B₁, B₂, B₆, B_12, C, PABA, and PP). These three measured parameters are gradient time, temperature, and ternary eluent composition (B1/B2) and the seven calculated parameters are flow rate, column length, column internal diameter, dwell volume, extracolumn volume, %B (start), and %B (end). The design is based on 12 experiments in which, examining of the multifactorial effects of these 3 + 7 parameters on the critical resolution and selectivity, was carried out by systematical variation of all these parameters simultaneously. The 12 basic runs were based on two different gradient time each at two different temperatures, repeated at three different ternary eluent compositions (methanol or acetonitrile or a mixture of both). Multidimensional robust regions of high critical R_s were defined and graphically verified. The optimum method was selected based on the best resolution separation in the shortest run time for a synthetic mixture, followed by application on two pharmaceutical preparations available in the market. The predicted retention times of all peaks were found to be in good match with the virtual ones. In conclusion, the presented report offers an accurate determination of the design space for critical resolution in the analysis of water‐soluble vitamins by HPLC, which would help the regulatory authorities to judge the validity of presented analytical methods for approval.     

基于无线网络的塔吊群防碰撞系统的研究

根据无线网络的特点与塔吊群协同作业的安全要求,研究了工业环境下无线网络的实时性和可靠性,成功研制了塔吊群防碰撞系统,预防塔吊间的碰撞问题.     

基于特殊需要的运输问题

基于可持续发展和保护资源、环境的特殊需要,提出了三个新的运输问题.它们的数学模型都是含有不可微约束的双目标规划问题.还给出了求解这些问题的简便方法.     

基于DEA模型的合肥市制造业研发效率分析

基于合肥市第二次全国R&D资源清查公报最新数据,运用数据包络分析模型分析合肥市制造业12个行业大类在R&D活动中的投入产出效率.实证分析结果表明,行业大类间的研发效率差别较大,行业间对研发资源的管理使用水平不均.可通过加大研发资源的投入、人才引进、改进管理水平和调整行业规模进一步提高研发投入的效率.     

Integrated projects planning in IS departments: A multi-period multi-project selection and assignment approach with a computerized implementation

This paper highlights the subject of integrated projects planning (IPP) in contemporary IS departments, and presents a multi-period, multi-project selection and assignment approach (MPPA) to assist the departments in handling continuous project-based IS requests. The MPPA features a model to optimize the selection and assignment of IS projects. In the scope of multi-project, multi-period planning, the model innovatively considers the losses due to (1) the accumulated postponement of a previously unselected IS request and (2) the expected delay of ongoing projects when inserting a new project request. The MPPA also features an event-based decisional process for cumulative selection and assignment on a multi-period basis. Due to the complex and contextual nature of data in this paper, a computerized system is implemented for aiding the execution of the model and the process. The paper reports on an industrial case for a demonstration of the proposed work. Finally the paper compares the MPPA with related work to summarize the value and role it may play in the IPP context.     

A METHOD FOR PREDICTING HARBOR SEAL (PHOCA VITULINA) HAULOUT AND MONITORING LONG‐TERM POPULATION TRENDS WITHOUT TELEMETRY

Monitoring population trends in harbor seals (Phoca vitulina) generally involves two steps: (i) a census obtained from aerial surveys of haul‐out sites, and (ii) an upward correction based on the proportion of seals hauled out as estimated from a sample of telemetry‐tagged seals. Here we present a mathematical method for obtaining site‐specific correction factors without telemetry. The method also determines site‐specific environmental factors associated with haulout and provides algebraic equations that predict diurnal haul‐out numbers and correction factors as functions of these variables. We applied the method at a haul‐out site on Protection Island, Washington, USA. The haul‐out model and correction factor model were functions of tide height, current velocity, and time of day, and the haul‐out model explained 46% of the observed variability in diurnal haul‐out dynamics. Although the particular models are site‐specific, the general model and methods are portable. A suite of such models for haul‐out sites of a regional stock would allow managers to monitor long‐term population trends without telemetry.     

分子筛和金属有机骨架材料的工业展望(英文)

Crystalline nanoporous materials serve numerous pivotal functions in industrial chemistry. They provide crucial features for in- dustrial applications, such as high surface area, uniform porosity, inter-connected pore/channel system, accessible pore volume, high adsorp- tion capacity, ion-exchange ability, enhanced catalytic activity, and shape/size selectivity. As a well-established family of nanoporous materi- als, zeolites are of vital importance for the chemical and petrochemical industries. An emerging class of porous materials called metal organic frameworks (MOFs) also offer promise in various applications. Both zeolites and MOFs can play significant roles in fields that are critical for the future of our industrialized society. In the quest for raw material change, zeolites serve as catalysts providing the required shape/size selectivity towards base chemicals. In global efforts to transition into other transportation fuels such as Hydrogen, MOFs serve as the energy storage media. In the fight against environmental pollution, zeolites not only take part in capture and abatement of harmful substances, but also offer environmentally benign alternatives for many industrial processes. In this review, an industrial perspective on the synthesis and utilization of zeolites and MOFs for current and future applications is presented.     

ESI-MS/MS stability-indicating bioanalytical method development and validation for simultaneous estimation of donepezil, 5-desmethyl donepezil and 6-desmethyl donepezil in human plasma

A bioanalytical method was developed and validated to estimate donepezil, 6‐desmethyl donepezil and 5‐desmethyl donepezil simultaneously in human plasma using galantamine as an internal standard (IS). The chromatographic separation was achieved on a reverse‐phase XTerra RP (150 × 4.6 mm, 5 µm) column without affecting recovery (mean recovery > 60% with CV < 10%) for all analytes. ESI‐MS/MS multiple reaction monitoring in positive polarity was used to detect mass pairs for donepezil (m/z 380.3 → 91.3), 6‐desmethyl donepezil (m/z 366.4 → 91.3), 5‐desmethyl donepezil (m/z 366.4 → 91.3) and galantamine m/z (288.1 → 213.0). The linearity was established over a dynamic range of 0.339–51.870, 0.100–15.380 and 0.103–15.763 ng/mL for donepezil, 6‐desmethyl donepezil and 5‐desmethyl donepezil, respectively. The current method shows that minimal conversion of labile metabolites to parent donepezil in plasma as stability was successfully achieved for 211 days at ?15 °C storage temperature. The method was successfully applied to a clinical study after administration of 10 mg donepezil tablets to healthy male Indian volunteers. Copyright © 2011 John Wiley & Sons, Ltd.     

Quantitative Determination and Variation Trends of Six Alkaloids in Crude and Processed Corydalis Yanhusuo

A convenient, sensitive, and accurate analytical method using reversed-phase high-performance liquid chromatography coupled with ultraviolet-visible detection was investigated for the determination of 6 alkaloids (tetrahydrocoptisine, protopine, tetrahydropalmatine, coptisine, corydaline, and palmatine) in crude and processed samples of corydalis yanhusuo. The results revealed that the content of the alkaloids in crude corydalis yanhusuo samples varied from those of the processed samples. The concentrations of tetrahydrocoptisine, protopine, tetrahydropalmatine, coptisine, and corydaline were reduced after processing; however, the concentration of palmatine increased after processing. This method was established using a C₁₈ column (250 mm × 4.6 mm, 5 µm). The mobile phase, a mixture (19:81) of acetonitrile and a 0.6% solution of acetic acid (pH 3.5, adjusted using triethylamine), was used to elute the target compounds in the isocratic elution mode. The solvent flow rate was 1.0 mL/min, the column temperature was 35°C, and the detection wavelength was 280 nm. All of the calibration curves exhibited good linearity with R >0.9999. The inter- and intra-day precisions for all of the investigated components ranged from 0.10–2.64% RSD, and the recoveries were in the range of 97.3–102.5%. The validated method provides a new solution for analyzing the contents of crude and processed samples of corydalis yanhusuo.     

铝锰铁合金标准物质的研制

依据GB/T15000.3—2008、GB/T15000.5—1994、YB/T082—1996和相关ISO导则研制了铝锰铁合金化学分析用标准样品。样品经过加工混匀后,按要求进行粒度实验和均匀性检验。采用Minitab软件进行均匀性数据的正态性检验,然后用方差法进行均匀性检验,各元素F值均小于临界值F0.05,表明被检元素的均匀性良好。由7家有资质的实验室采用多种不同原理,准确、可靠的分析方法协作定值分析,对分析结果进行统计和处理,得到了定值元素的认定值。结果表明该标准物质均匀性和稳定性以及定值准确性均达到国家标准物质的性能指标,符合国家计量技术规范的要求。