Statistical methods for HIV dynamic studies in AIDS clinical trials

Studies of HIV dynamics in AIDS research are very important for understanding pathogenesis of HIV infection and for assessing the potency of antiviral therapies. Since the viral dynamic results from clinical data were first published by Ho et al. and Wei et al., the study of HIV-1 dynamics in vivo has drawn a great attention from AIDS clinicians and researchers. Although the important findings from HIV dynamic studies have been published in many prestigious scientific journals, statistical methods for estimating viral dynamic parameters have not been paid enough attention by HIV dynamic investigators. The estimation methods in many viral dynamic studies are very crude and inefficient. In this paper, we review the statistical methods and mathematical models for HIV dynamic data analysis developed in recent years. We also address some practical issues and share our experiences in the design and analysis of viral dynamic studies. Some principles and guidelines for the design and analysis of viral dynamic studies are provided. The methodologies reviewed in this paper are also applicable to studies of other viruses such as hepatitis B virus or hepatitis C virus. We also pose some challenging statistical problems in this area in order to stimulate further study by the statistical research community.     

Some methods available for treatment of waste water in the dairy industry

Methods of treating dairy waste water are reviewed. Typical ranges of the effluent characteristics are presented, conventional methods of treatment are discussed and their disadvantages highlighted. Emphasis is placed on less common techniques of treatment including processes involving by-product recovery.     

A revision of the luminance decay time estimation methods for photoluminescent products

We present a comparison between the methods used by two regulatory standards to estimate the luminance decay time for photoluminescent safety signs and safety way guidance systems (SWGS). One of these standards is the international ISO 16069. The other is the Spanish regulatory standard UNE 23035‐1. Both standards define the luminance decay time as the time for the luminance emitted by the photoluminescent sample to reach 0.3 mcd/m² after the excitation light over the sample is removed. Due to the fact that decay time can be really long, they propose methods to estimate it by extrapolation. The points suggested by each standard to adjust the luminance decay time curve are quite different and so are the results obtained with them. To compare both methods, four different photoluminescent safety signs were tested using the methods provided by these two regulatory standards. The samples were illuminated for 5 min with a xenon‐arc source of light; luminance measurements after illumination were made with a B‐510 LMT photometer, for an interval of time according to methods explained by the standards. The results were compared with real measurements of luminance decay time for each sample, allowing the luminance value to reach 0.3 mcd/m². Results obtained from the extrapolating methods provided by each standard showed that standard ISO 16069 was much more accurate than UNE 23035‐1, which showed important deviations from real decay time values. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2011     

露天矿短期计划优化的几项关键技术方法

在研制露天矿短期剥采计划优化软件包过程中，采用了几项计算机处理方法和技术，开发了交互式屏幕彩色字符图设计系统。采用更适用于块段模型显示的压缩链环阵图形数据结构及采剥区域填充的算法──字符段填充算法，极大地节省了内存空间，减少了种子点进出栈的次数和堆栈深度，提高了交互式设计系统的处理速度，更适合大型露天煤矿短期剥采计划设计。     

A comparative study of the available electrochemical methods for the investigation of epoxy and fluoropolymer coatings deterioration

The corrosion behaviour of phosphatized galvanized steel coated with both epoxy films of different thickness and fluoropolymer films has been studied by means of a.c. impedance spectroscopy (EIS), break-point frequency, potentiodynamic measurements and faradaic distortion methods as well as by the salt spray test. It was observed that the degradation of protective films appears after a long-lasting initial period but once the process starts, the area of defects increases with exposure time. The rate of degradation depends both on type of polymer and of film thickness for the same type of polymer. The same behaviour can be observed from the decrease in pore resistance and charge-transfer resistance (EIS) and increase in double-layer capacitance (a.c. impedance measurements) and corrosion current (potentiodynamic measurements and harmonic analysis).     

Association of body segments and body composition with blood pressure in young adults

Skeletal structure and body composition may be altered permanently in response to aggressions during critical periods of growth. This increases propensity to adverse effects in adulthood. The study explored the association of anthropometric variables of body size and proportions and of body composition with systolic (SBP) and diastolic (DBP) blood pressure (BP) in young adults. We studied 166 men and 246 women age 20-34. SBP, DBP, weight, stature, sitting height, circumferences (waist, hip), breadths (biacromial, biiliac) and skinfolds (bicipital, tricipital, subscapular, suprailiac) were assessed. BMI, waist-hip ratio (WHR), waist-stature ratio, and Sigma skinfolds-stature were calculated. Pearson correlations were determined for anthropometric variables with SBP and DBP and linear regression models for SBP and DBP were developed by sex. Correlation coefficients between indicators and BP were significant, except for stature and SBP and DPB, and WHR with DBP in women; and stature with DBP, biiliac breadth and WHR with SBP, and sitting height with SBP and DPB in men. SBP and DPB were explained by weight, BMI, and biiliac breadth in multivariable analysis in women, where 15.4% and 10.8% of variance of SBP and DPB was explained. In men, SBP was explained by weight, Sigma skinfolds and WHR, and DBP by Sigma skinfolds; models explained almost 20% of SBP and DPB variance. No association was found between BP and past malnutrition indicators. Biiliac breadth, weight and BMI in women, and weight, WHR and Sigma skinfolds in men explained BP. The use of biiliac breadth in the assessment of hypertension risk in women should be explored further.     

陶瓷坯釉料配方系统的研制

陶瓷坯釉料配方的最优化计算是工艺技术人员需解决的工艺关键技术问题之一。采用C语言设计了复合形法陶瓷配料优化模块,并在Visual Foxpro5.0平台上开发了陶瓷数据库管理系统及其应用软件。该软件包包括数据库管理、最优化计算、性能计算、系统维护、帮助系统等五大模块。初步应用表明:该软件包功能齐全、计算速度很快,能满足陶瓷企业配方设计与管理要求。     

Evaluation of mathematical distribution methods for the determination of triglyceride composition

The triglyceride composition of a number of animal and vegetable fats was determined directly by means of selective argentation and lipase hydrolysis, and compared to that given by the 1,3-random,2-random method of analysis described by Vander Wal [JAOCS37, 18 (1960)]. Exceptions to the basic assumption of the 1,3-random,2-random method that the fatty acids in the 2-position are distributed randomly are reported. The analyses of some fats determined by the 1,3-random,2-random method agreed closely with those determined by the direct method, but the overall results indicated that methods based on mathematical distribution patterns generally are not as precise as direct methods. Presented at AOCS meeting, Houston, 1965.     

New elemental composition analysis methods for the LEA-S500 analyzer

The LEA-S500 laser analyzer is considered as regards the main advantages in use for analysis of elemental composition of a wide range of substances and materials. Methods are described for the quantitative analysis of titanium-based alloys, rutile concentrates, and quartz sands. A comparison is made of the methods used in measurements with the LEA-S500 and those in wet chemistry, x-ray fluorescence, and atomic absorption. Translated from Novye Ogneupory, No. 4, pp. 132 – 135, April, 2009. The LEA-S500 laser elemental composition analyzer has been registered in the State register of measuring instruments No. 38154–08 and is permitted for use in the Russian Federation, certificate BY, C.31.004.A No. 32154.     

运用恒定组分技术评价化学阻垢剂的阻垢效果

建立了基于单一电导率监测 ,保持碳酸钙溶液析晶过程中 ,溶液中各组分浓度恒定的“恒定组分”实验技术 ,研究了不同种类的非化学配比阻垢剂的阻垢效果和不同浓度的PBTC的阻垢效果。发现不同的阻垢剂或者相同阻垢剂不同剂量所起到的阻垢效果反映在“抑制平台”的长短上。平台期过后 ,晶体的生长与不加阻垢剂的实验无显著的区别。实验图形反映了恒定组分系统具有很高的灵敏度和高度的可重复性。我们认为 ,平台长短反映了阻垢效果 ,可以作为评价阻垢剂效能的指标     

A study of available particle size standards for calibrating electrical sensing zone methods

A wider range of particle size standards have become available in recent years for calibration of the electrical sensing of zone techniques. In order to obtain accurate particle size results by these techniques, suitable microscopic measurements have been made to establish reliable standards for calibration. A comparison between microscopic and sensing zone measurements was made to evaluate the accuracy of the Coulter Counter and Celloscope.     

过磷酸钙中有效磷测定方法的比较

现行化工行业标准过磷酸钙 ( HG 2 740 95)有效磷的测定提取剂选用碱性柠檬酸铵 ,分为水溶性磷和柠檬酸铵性磷两步提取 ,操作繁琐耗时 ,试剂消耗量大。有文献介绍用草酸铵一步提取法进行有效磷的测定 ,但提取不够完全 ,结果偏低。本文探讨用EDTA一步直接提取有效磷 ,较之现行化工行业标准规定的方法用时减少 2 h以上 ,分析结果与标准法结果的绝对差值≤ 0 .2 %。1　碱性柠檬酸铵二步提取法 (标准法 )水溶性磷以水为提取剂提取 ,枸溶性磷以碱性柠檬酸铵溶液为提取剂进行提取 ,吸取部分两种溶液 ,加合后以硝酸酸化 ,用磷钼酸喹啉重量法或容…     

乳液临界聚沉浓度及其测定方法

综述了几种常见的临界聚沉浓度(CCC)测试方法及其理论模型。     

Critical evaluation of sequential extraction and sink-float methods used for the determination of Ga and Ge affinity in lignite

The affinities of Ga and Ge in lignite were determined using sequential extraction (SE) and element affinity calculation (EAC) based on sink-float data. For this study a bulk lignite sample was fractioned into two sets. The first set of samples (A) consisted of the different grain sizes fractions; the second one set (B) was prepared by density fractionation. Sequential extractions [1] were performed on both sets of fractions with very good agreement between determined organic elements affinities (OEA of Ga evaluated from A data is 32%, from B data 35%; OEA of Ge evaluated from A data is 31% and from B data 26%). The data of B lignite fractions were evaluated using two element affinity calculations: (a) EAC (I) of Klika and Kolomazník [2] and b) newly prepared subroutine EAC (II) based on quantitative contents of lignite macerals and minerals. There was also good agreement between both methods obtained (OEA of Ga calculated by EAC (I) is 83% and by EAC (II) 77%; OEA of Ge calculated by EAC (I) is 89% and by EAC (II) 97%). The significant differences of organic elements affinities of Ga and Ge evaluated by sequential extraction and by element affinity calculation based on sink-float data are discussed.