多法测量塑料薄膜水蒸气透过量的一致性研究

目的：评价杯式法、电解法和红外法3种方法测量塑料薄膜水蒸气透过量的数据一致性。方法：采用厚度均匀的塑料薄膜,经杯式法、电解法和红外法3种方法测量其水蒸气透过量,等效检验评价测定结果的一致性。结果：杯式法、电解法和红外法测量塑料薄膜的水蒸气透过量分别为7.03、7.02和6.99 g/（m²·day）。结论：3种方法的测量结果等效。这为多种方法测量塑料薄膜水蒸气透过量的实验室数据对比提供了一定的数据基础。     

Standards for Instrument Migration When Implementing Paper Patient-Reported Outcome Instruments Electronically: Recommendations from a Qualitative Synthesis of Cognitive Interview and Usability Studies

Objectives

To synthesize the findings of cognitive interview and usability studies performed to assess the measurement equivalence of patient-reported outcome (PRO) instruments migrated from paper to electronic formats (ePRO), and make recommendations regarding future migration validation requirements and ePRO design best practice.

Relationship between sample size and the definition of equivalence in non-inferiority drug studies

Statistical testing of clinical trial data leads to acceptance of a hypothesis if a test of the opposite (null) hypothesis (H0) fails to reach a critical probability value. The usual aim is to demonstrate that a new treatment is superior to a comparator, whence H0 is that the two treatments are the same. By contrast, in studies designed to show that a new treatment is equivalent to an existing therapy, the same principle is satisfied by an amended null hypothesis, that the treatments differ by more than a defined amount. This reversal entails subtle but important logical and practical problems which affect particularly the calculation of sample size. The choice of the limits used to define equivalence is critical to the calculation of sample size in a manner not previously discussed, and in the interpretation of data in relation to the probability of Type I and Type II errors. Investigators, regulatory bodies and institutional ethics committees must ensure that the range of values chosen to indicate equivalence is clinically appropriate and be aware of the effect of this decision on possible errors in accepting or rejecting H0.     

Neural selectivity,efficiency, and dose equivalence in deep brain stimulation through pulse width tuning and segmented electrodes

BackgroundAchieving deep brain stimulation (DBS) dose equivalence is challenging, especially with pulse width tuning and directional contacts. Further, the precise effects of pulse width tuning are unknown, and recent reports of the effects of pulse width tuning on neural selectivity are at odds with classic biophysical studies.MethodsWe created multicompartment neuron models for two axon diameters and used finite element modeling to determine extracellular influence from standard and segmented electrodes. We analyzed axon activation profiles and calculated volumes of tissue activated.ResultsWe find that long pulse widths focus the stimulation effect on small, nearby fibers, suppressing distant white matter tract activation (responsible for some DBS side effects) and improving battery utilization when equivalent activation is maintained for small axons. Directional leads enable similar benefits to a greater degree. Reexamining previous reports of short pulse stimulation reducing side effects, we explore a possible alternate explanation: non-dose equivalent stimulation may have resulted in reduced spread of neural activation. Finally, using internal capsule avoidance as an example in the context of subthalamic stimulation, we present a patient-specific model to show how long pulse widths could help increase the biophysical therapeutic window.DiscussionWe find agreement with classic studies and predict that long pulse widths may focus the stimulation effect on small, nearby fibers and improve power consumption. While future pre-clinical and clinical work is necessary regarding pulse width tuning, it is clear that future studies must ensure dose equivalence, noting that energy- and charge-equivalent amplitudes do not result in equivalent spread of neural activation when changing pulse width.     

Rheological and molecular weight comparisons of approved hyaluronic acid products – preliminary standards for establishing class III medical device equivalence

Hyaluronic acid of various molecular weights has been in use for the treatment of osteoarthritis knee pain for decades. Worldwide, these products are regulated as either as drugs or devices and in some countries as both. In the US, this class of products is regulated as Class III medical devices, which places specific regulatory requirements on developers of these materials under a Pre-Market Approval process, typically requiring data from prospective randomized controlled clinical studies. In 1984 pharmaceutical manufacturers became able to file an Abbreviated New Drug Application for approval of a generic drug, thus establishing standards for demonstrating equivalence to an existing chemical entity. Recently, the first biosimilar, or ‘generic biologic’, was approved. Biosimilars are biological products that are approved by the FDA because they are ‘highly similar’ to a reference product, and have been shown to have no clinically meaningful differences from the reference product. For devices, Class II medical devices have a pathway for declaring equivalence to an existing product by filing a 510 k application for FDA clearance. However, until recently no equivalent regulatory pathway was available to Class III devices. In this paper, we consider the critical mechanical performance parameters for intra-articular hyaluronic products to demonstrate indistinguishable characteristics. Analogous to the aforementioned pathways that allow for a demonstration of equivalence, we examine these parameters for an existing, marketed device and compare molecular weight and rheological properties of multiple batches of a similar product. We propose that this establishes a scientific rationale for establishing Class III medical device equivalence.     

配对二项数据等效性／非劣效性评价的样本含量估计和假设检验

新药及医疗器械临床试验中，有时会涉及到两比较组采用配对设计获得的二项反应数据（配对二项数据）的等效性／非劣效性问题。两独立组率之间等效性／非劣效试验的样本含量估计及假设检验方法已较为成熟，但对于配对二项数据两组率之间的等效性／非劣效性试验的样本含量估计及假设检验方法还应用不多。本文介绍了一种渐进的基于约束极大似然估计的方法用于配对二项数据两组率之间的等效性／非劣效性试验的样本含量估计和假设检验，借助一个超声诊断仪临床试验的例子阐明了本方法的应用，还就有关实际问题进行了讨论。     

Measuring quality of life among cervical cancer survivors: preliminary assessment of instrumentation validity in a cross-cultural study

Background With growing interest in cross-cultural and multicultural cancer-related quality of life studies, the need to assess reliability and validity of quality of life measures for linguistically and culturally diverse cancer survivors is pressing. Methods Reliability and validity of the English and Spanish versions of the Functional Assessment of Cancer Therapy (FACT)-G subscales were tested with a sample of English-speaking European American (n = 273) and ethnic minority American (n = 194), and Spanish-speaking Latina (n = 199) cervical cancer survivors in the U.S. Results Reliability coefficients (Cronbach’s alpha) were 0.76 or higher across ethnic/linguistic groups except for the emotional wellbeing subscale among Spanish-speaking Latinas (α = 0.64). Factor analyses demonstrated overall measurement equivalence across groups with some ethnic/linguistic variations: there were greater differences between linguistic groups than between ethnic groups. Additionally, the scale’s factor structure was less satisfactory for Spanish-speaking Latinas. The subscales had good concurrent validity with appropriate subscales of the Short Form (SF)-12 and Rand/SF-36 General Health subscale (Pearson’s r 0.53–0.66), suggesting each subscale was assessing its intended construct. Conclusion The overall psychometric properties of the FACT-G were cross-culturally equivalent. However, more validation studies are needed for non-English speaking populations particularly with emotional wellbeing. In addition, disaggregated analyses on linguistic groups are recommended unless cross-cultural equivalence is established. All participants in this study have provided written informed consent as required by the University of California at Los Angeles Institutional Review Board.     

等值理论与医学翻译

翻译的等值概念一直是西方现代翻译理论中的一个核心问题。有关翻译等值理论与实践的探讨层出不穷,然而医学翻译中的等值问题却极少被涉及。本文以翻译等值相关理论为基础,从词汇、句子和篇章等值方面讨论医学翻译的等值问题,揭示等值理论对医学翻译的指导作用。     

Testing the measurement equivalence of paper and touch-screen versions of the EQ-5D visual analog scale (EQ VAS)

OBJECTIVES: This study examined the measurement equivalence of the original paper-based vertical format of the EQ-5D visual analog scale (EQ VAS) with a touch-screen computer-based horizontal format. METHODS: A total of 314 subjects were administered two modes of the EQ VAS in a randomized crossover design. One mode was the original paper-based 20 cm vertical EQ VAS; the other mode was touch-screen-based. Measurement equivalence was assessed by testing the 95% confidence interval of the mean differences from an equivalence threshold of -3 to +3 points on the VAS and evaluating the intraclass correlation coefficient (ICC). RESULTS: The adjusted mean (SE) EQ VAS score was 80.96 (0.87) on the paper and 79.59 (0.85) on the touch-screen. The mean (CI) difference between scores on the two formats was 1.37 with a confidence interval of 0.175-2.559, wholly contained within the equivalence interval. The ICC was 0.75, indicating acceptable agreement between the two modes. Almost a third (30.1%) of the respondents reported identical scores on both formats. CONCLUSION: These results provide evidence for the measurement equivalence of this EQ VAS touch-screen administration mode with the original paper mode.