Dose-response modeling of continuous endpoints.

A family of (nested) dose-response models is introduced herein that can be used for describing the change in any continuous endpoint as a function of dose. A member from this family of models may be selected using the likelihood ratio test as a criterion, to prevent overparameterization. The proposed methodology provides for a formal approach of model selection, and a transparent way of assessing the benchmark dose. Apart from a number of natural constraints, the model expressions follow from an obvious way of quantifying differences in sensitivity between populations. As a consequence, dose-response data that relate to both sexes can be efficiently analyzed by incorporating the data from both sexes in the same analysis, even if the sexes are not equally sensitive to the compound studied. The idea of differences in sensitivity is closely related to the assessment factors used in risk assessment. Thus, the models are directly applicable to estimating such factors, if data concerning populations to be compared are available. Such information is valuable for further validation or adjustment of default assessment factors, as well as for informing distributional assessment factors in a probabilistic risk assessment. The various applications of the proposed methodology are illustrated by real data sets.     

经典名方猪苓汤基准样品质量评价方法研究

目的 建立经典名方猪苓汤基准样品的定性和定量检测方法,为其质量标准的建立及复方制剂的开发提供数据支撑和研究基础。方法 建立猪苓汤基准样品HPLC特征图谱,采用国家药典委员会出版的“中药色谱指纹图谱相似度评价系统”（2012年版）计算相似度;确定基准样品含量测定指标成分并通过HPLC建立含量测定方法,进行相关方法学考察;研究建立猪苓汤中处方药味薄层鉴别方法;计算15批基准样品的干膏率及指标成分转移率、水分。结果 特征图谱共标定8个共有峰,分别归属泽泻和阿胶,其中指认3个共有峰,分别为泽泻醇A（峰1）、泽泻醇B（峰2）、23-乙酰泽泻醇B（峰3）,15批猪苓汤基准样品质量评价结果表明相似度均大于0.95,可表征猪苓汤基准样品的质量特性;含量测定指标成分确定为阿胶中的L-羟脯氨酸、甘氨酸、丙氨酸、脯氨酸,并建立含量测定方法,方法学考察均符合要求;同时建立猪苓、茯苓、泽泻的薄层鉴别方法。计算15批猪苓汤基准样品的平均干膏率为21.53%,平均水分为3.64%,指标成分L-羟脯氨酸、甘氨酸、丙氨酸、脯氨酸平均转移率分别为90.89%、90.25%、90.29%、91.28%,所有数据均未出现离散...     

一种基于子空间LQG基准的MPC性能分析方法

为保证过程零稳态误差,过程控制器通常包含积分环节。为了考虑积分作用,针对无穷时域MPC目标函数,采用控制增量代替控制量设计LQG(Linear Quadratic Gaussian)控制器,提出一种基于子空间的LQG基准计算方法用于MPC性能分析。该方法利用过程闭环运行数据和子空间辨识算法估计子空间矩阵和噪声方差,进而求取最优LQG基准方差。在Wood Berry二元精馏塔上的仿真验证了所提方法的有效性。     

The impact of prolonged cadmium exposure and co-exposure with polychlorinated biphenyls on thyroid function in rats

Endocrine-disrupting chemicals currently represent one of the major concerns and this study was aimed to investigate the effects of different doses of cadmium, widespread toxic metal, on the levels of thyroid hormones and to calculate Benchmark doses for these effects. Furthermore, the effects of co-exposure to cadmium and polychlorinated biphenyls on thyroid function were investigated. Six orally-treated groups of rats were receiving 0.3, 0.6, 1.25, 2.5, 5 and 10 mg Cd/kg b.w./day, five groups were orally treated with 0.5, 1, 2, 4 and 8 mg PCBs/kg b.w./day, while nine groups of rats were orally-treated with different dose combinations of Cd and PCBs (0.6, 1.25 and 2.5 mg Cd/kg b.w. and 2, 4 and 8 mg PCBs/kg b.w./day), during 28 days. Thyroid hormones were adversely affected by cadmium, with most prominent effect observed on triiodothyroxine levels indicating Cd interference with thyroid function at extrathyroidal level. Calculated Benchmark doses for Cd effects on thyroid hormones indicate triiodothyroxine as the most sensitive one that can be used as a basis for risk assessment. This study also implicates possible synergistic effects of Cd and PCBs on thyroid function as a consequence of their interference at different levels of thyroid homeostasis.     

婴儿手的色泽与手区胃信息影像表达关系研究

目的研究手区胃影像图基准值的"测量基准"和校验方法。方法以中西医理论为指导,采用验证医学模式,首先模拟健康胃黏膜的手区胃影像图,然后对10个健康婴儿手色泽的影像图进行分析。结果健康婴儿整体上最接近健康胃黏膜的标准,健康婴儿的手区胃影像图与健康胃黏膜的手区影像模拟图是相符的,样本与理论推论结果得到互证。结论以健康婴儿手的色泽为手区胃影像图基准值的"测量基准"是科学的,且易取材。     

保元汤物质基准UPLC-PDA指纹图谱的建立及化学成分指认

目的:建立保元汤物质基准的指纹图谱并对其共有峰进行成分指认。方法:制备15批保元汤物质基准,采用超高效液相色谱-二极管阵列检测器法(UPLC-PDA)测定15批保元汤物质基准的指纹图谱,并开展方法学研究;使用ACQUITY UPLC BEH Shield C18色谱柱(2.1 mm×100 mm,1.7μm),流动相0.05%甲酸水溶液(A)-0.05%甲酸乙腈溶液(B)梯度洗脱(0~0.5 min,5%~19%B;0.5~6 min,19%B;6~10 min,19%~27%B;10~20 min,27%~45%B;20~20.1 min,45%~95%B;20.1~23 min,95%B),流速0.4 mL·min-1,检测波长203 nm和260 nm,柱温30℃,进样量2μL;采用"中药指纹图谱相似度评价系统"(2012版)建立指纹图谱,并生成对照指纹图谱;采用超高效液相色谱-电喷雾串联质谱法(UPLC-ESI-MS/MS)和对照品比对等方式进行保元汤物质基准的成分指认,质谱条件为全信息串联质谱(MSE)扫描模式检测,质量扫描范围m/z 50~1200。结果:15批保元汤物质基准与对照指纹图谱的相似度均>0.90,共有37个共有峰,通过UPLC-ESI-MS/MS指认了其中22个,分别为甘草苷,人参皂苷Rg1,人参皂苷Rb1,人参皂苷Re等,均来源于人参、黄芪、甘草、生姜4味药材。结论:该方法精密度、重复性、稳定性良好,表征了保元汤组分整体特征,为该经典名方的颗粒剂开发提供了实验依据。     

International variation in length of stay in intensive care units and the impact of patient-to-nurse ratios

ObjectiveTo assess variation in ICU length of stay between countries with varying patient-to-nurse ratios; to compare ICU length of stay of individual countries against an international benchmark.DesignSecondary analysis of the DecubICUs trial (performed on 15 May 2018).SettingThe study cohort included 12,794 adult ICU patients (57 countries). Only countries with minimally twenty patients discharged (or deceased) within 30 days of ICU admission were included.Main outcome measureMultivariate Cox regression was used to evaluate ICU length of stay, censored at 30 days, across countries and for patient-to-nurse ratio, adjusted for sex, age, admission type and Simplified Acute Physiology Score II. The resulting hazard ratios for countries, indicating longer or shorter length of stay than average, were plotted on a forest plot. Results by country were benchmarked against the overall length of stay using Kaplan-Meier curves.ResultsPatients had a median ICU length of stay of 11 days (interquartile range, 4–27). Hazard ratio by country ranged from minimally 0.42 (95% confidence interval 0.35–0.51) for Greece, to maximaly1.94 (1.28–2.93) for Lithuania. The hazard ratio for patient-to-nurse was 0.96 (0.94–0.98), indicating that higher patient-to-nurse ratio results in longer length of stay.ConclusionsDespite adjustment for case-mix, we observed significant heterogeneity of ICU length of stay in-between countries, and a significantly longer length of stay when patient-to-nurse ratio increases. Future studies determining underlying characteristics of individual ICUs and broader organisation of healthcare infrastructure within countries may further explain the observed heterogeneity in ICU length of stay.     

经典名方温胆汤物质基准量值传递分析

目的: 建立温胆汤物质基准的高效液相色谱指纹图谱及指标性成分含量测定的方法,结合化学模式识别法探索饮片-物质基准的量值传递关系。方法: 据古法制备15批温胆汤物质基准,经高效液相色谱法对15批饮片和物质基准的指纹图谱、指标性成分含量进行测定,结合出膏率、指纹图谱相似度、特征峰的归属及指标性成分的转移率进行量值传递研究。结果: 15批温胆汤物质基准的指纹图谱的相似度均大于0.9;共归属20个共有峰,陈皮3个、竹茹1个、枳实5个、生姜1个、甘草2个、陈皮和枳实共有6个、陈皮和竹茹共有1个、陈皮和枳实及甘草共有1个;15批温胆汤物质基准中鸟苷、尿苷、6-姜辣素和橙皮苷的含量范围分别为0.020 1%~0.037 2%、0.032 5%~0.058 3%、0.034 1%~0.085 3%和1.433 8%~3.419 0%,鸟苷、尿苷和6-姜辣素转移率范围分别为53.01%~93.42%、90.11%~248.31%和19.35%~33.97%;出膏率范围19.34%~24.53%。结论: 采用指纹图谱、出膏率及指标性成分含量相结合的模式对经典名方物质基准的量值传递过程进行分析,初步拟定的物质基准质量标准可为后续现代制剂的开发提供依据与参考。     

Guidelines for Reporting and Using Prediction Tools for Genetic Variation Analysis

Computational prediction methods are widely used for the analysis of human genome sequence variants and their effects on gene/protein function, splice site aberration, pathogenicity, and disease risk. New methods are frequently developed. We believe that guidelines are essential for those writing articles about new prediction methods, as well as for those applying these tools in their research, so that the necessary details are reported. This will enable readers to gain the full picture of technical information, performance, and interpretation of results, and to facilitate comparisons of related methods. Here, we provide instructions on how to describe new methods, report datasets, and assess the performance of predictive tools. We also discuss what details of predictor implementation are essential for authors to understand. Similarly, these guidelines for the use of predictors provide instructions on what needs to be delineated in the text, as well as how researchers can avoid unwarranted conclusions. They are applicable to most prediction methods currently utilized. By applying these guidelines, authors will help reviewers, editors, and readers to more fully comprehend prediction methods and their use.