QUANTITATIVE EVOKED POTENTIAL CORRELATES OF THE PROBABILITY OF EVENTS

A late positive-going component (P₃) of the average evoked potential recorded from human scalp was shown to be quantitatively related to a priori stimulus probability both when the S was told the identity of the stimulus before it was presented and when the S was not told, and was instructed to guess. In the guessing situation, the amplitude of P₃ was much larger and was influenced not only by the a priori probability of events determined by the experimenter but also by the interaction of these probabilities with the S's guessing behavior. The amplitude of the late positive component was inversely related to the proportion of trials in which a particular event was associated with a particular guess, i.e., the proportion of hits and misses. It was larger the more unexpected the outcome of the guess. This relationship held for different methods of manipulating the probability of two events.     

光照度计法测量公共场所室内桌面照度不确定度评定

目的建立现场检测工作中室内桌面照度测量不确定度评定的方法,对不确定度分量进行评定,计算出扩展不确定度值。方法根据《测量不确定度评定与表示(JJF 1059.1-2012)》和《公共场所卫生检验方法第1部分:物理因素(GB18204.1-2013)》的方法,对现场测量公共场所(候诊室)室内桌面照度值的各不确定度分量进行分析和计算,最终合成标准不确定度。结果本例用照度计法对某候诊室室内照度进行测量结果为:(225±10.74)lx,扩展不确定度为10.74 lx,其中采样高度是最大不确定度分量。结论该评定方法可用于现场检测中照度值测量的不确定度评定。     

The History and Future of the “ISPOR Value Flower”: Addressing Limitations of Conventional Cost-Effectiveness Analysis

ObjectivesSince its publication as part of the 2018 ISPOR Special Task Force (STF) on US Value Assessments, the “ISPOR value flower,” with its petals highlighting elements that may be overlooked or underappreciated in conventional drug value assessments, has been discussed and debated. We review the history of the value flower, describe recent developments, and consider implications for future value assessments.MethodsWe discuss various antecedents to the value flower, as well as conceptual and empirical articles published in the past 4 years.ResultsSince the publication of the ISPOR STF report, researchers have provided more rigorous theoretical and mathematical foundations for certain novel value elements (eg, severity of illness, value of insurance, value of hope) through “generalized risk-adjusted cost-effectiveness analysis,” which incorporates risk aversion in people’s preferences and uncertainty in treatment outcomes. Empirical estimates are also emerging to support key elements, such as insurance value, real option value, value of hope, and value of knowing. Although health technology assessment bodies have applied or are considering certain elements (eg, severity modifiers to cost-effectiveness thresholds), other elements have yet to gain traction.ConclusionsFive years after the STF began its work, the development of novel value measures continues to evolve. Although it is encouraging to see supporting empirical studies emerging, more are needed. Additional efforts are also needed to illustrate how the estimates can be used in the deliberative processes that are integral to health technology assessments.     

Statistical concepts and biomedical research

An understanding of statistical concepts is important for biomedical researchers. Statistics and probability are the scientific basis for dealing with sources of variation inherent in most biologic processes. This paper provides an introduction to the statistical framework that is fundamental to scientific methods of inquiry. Topics covered include the role of statistics, hierarchy of evidence, reliability and bias, sample size and power, random samples and random allocation, hypothesis testing, estimation, statistical inference, and publication bias. Future papers will focus on specific statistical techniques commonly used in biomedical research.     

The refinement of uncertainty/safety factors in risk assessment by the incorporation of data on toxicokinetic variability in humans.

The derivation of safe levels of exposure in humans for compounds that are assumed to cause threshold toxicity has relied on the application of a 100-fold uncertainty factor to a measure for the threshold, such as the no observed adverse effect level (NOAEL) or the benchmark dose (BMD). This 100-fold safety factor consists of the product of two 10-fold factors allowing for human variability and interspecies differences. The International Programme on Chemical Safety has suggested the subdivision of these 10-fold factors to allow for variability in toxicokinetics and toxicodynamics. This subdivision allows the replacement of the default uncertainty factors with a chemical-specific adjustment factor (CSAF) when suitable data are available. This short review describes potential options to refine safety factors used in risk assessment, with particular emphasis on pathway-related uncertainty factors associated with variability in kinetics. These pathway-related factors were derived from a database that quantified interspecies differences and human variability in phase I metabolism, phase II metabolism, and renal excretion. This approach allows metabolism and pharmacokinetic data in healthy adults and subgroups of the population to be incorporated in the risk-assessment process and constitutes an intermediate approach between simple default factors and chemical-specific adjustment factors.     

火焰原子吸收法测定生活饮用水中锰的不确定度分析

目的：给出火焰原子吸收分光光度法测定生活饮用水中锰的测量不确定度。方法：找出影响不确定度的因素，对不确足度进行分析，评估。结果：对火焰原子吸收分光光度法测定生活饮用水中锰给出了测量不确定度。结论：分析了使用标准曲线法定量的这一类型不确定度的计算方法和步骤，在实际工作中有较强的实用价值。     

Theorizing About Social Support and Health Communication in a Prostate Cancer Support Group

This article inquires into whether and how uncertainty reduction theory and problematic integration theory, two theories relevant to social support as enacted within a chapter of the Man-to-Man prostate cancer support group, inform us of how such groups can assist group members most effectively. Interview data from members of a prostate cancer support group shed light on theoretical assumptions about uncertainty. Although the group applies elements of both theories, prostate cancer survivors likely would benefit from a more comprehensive and flexible treatment of social support theory.     

Development of a lyophilized soybean paste certified reference material for the analysis of ochratoxin A

A certified reference material (CRM) [²KRISS CRM # 108-10-018] for the analysis of ochratoxin A (OTA) in doenjang (fermented soybean paste and popular food in Korea) was produced to ensure the reliability of analytical results in testing laboratories. A home-made doenjang was chosen as a raw material after testing its OTA level. The raw material was freeze-dried, pulverized, sieved and homogenized. An isotope-dilution-liquid chromatography/tandem mass spectrometric method (ID-LC/MS/MS) which was previously developed and validated in this laboratory was used as a higher-order reference method for characterization, homogeneity studies, and short-term stability studies. The CRM had good between-bottle homogeneity with 0.56% relative standard deviation among 10 selected units. The stability of the CRM at −70 °C (the storage condition in our laboratory) and at −20 °C (the possible storage temperature at user sites) were tested for up to 8 months. No change in the OTA content was observed within the measurement uncertainty. The stability of the CRM at room temperature (for regular use and transportation) was also tested and confirmed. The certified value was (49.50 ± 1.17) μg/kg, where the expanded uncertainty was in the confidence level of 95%.