核糖核酸标准物质研制与应用进展

核糖核酸(RNA)标准物质是保证核酸体外诊断数据准确一致的重要实物标准,广泛用于病毒类疾病的检测、仪器校准、试剂盒评价及能力验证等工作中,其目的是保证测量过程和测量结果的准确一致。自1997年,WHO研制出了首个针对核酸扩增技术的丙型肝炎核酸国际标准物质,使全球不同实验室、不同方法检测的结果有了可比性。截至2023年,中国在国家标准物质资源共享平台发布的RNA有证标准物质有近百种,对于RNA标准物质的研究与应用,日益受到世界各国计量机构、相关国际学术组织与企业的重视,尤其是新型冠状病毒疫情暴发后,RNA标准物质成为了生物标准物质的研制热点。随着标准物质研制技术的不断发展,标准物质的量值准确性也有所提升,为测量结果的准确一致提供保障。通过对当前RNA标准物质的制备方法、分装、定值技术、不确定度评定及应用领域进行综述,为RNA标准物质的研制工作以及未来在临床医学、农业生产、动物医学、食品安全等领域的应用提供参考。     

数字PCR技术在核酸标准物质研制中的应用

在标准物质研制领域,生物标准物质的研制逐渐成为了研究热点,同时基于核酸的检测技术的开发与应用又推动了核酸标准物质的进程。核酸标准物质需要高级别、精准的定值方法,数字PCR作为单分子定量技术得到了广泛的应用。数字PCR是一种测定核酸分子的绝对定量方法,如微滴式数字PCR是采用油包水形成的微滴作为反应室,将含有DNA模板的反应溶液分配到大量独立的反应室中进行扩增反应,再通过统计反应室中的阳性信号来定量DNA的拷贝数,从而达到精确定量核酸拷贝数的目的。综述了近年来关于数字PCR及其在核酸标准物质研究领域的最新应用进展,重点综述了其在转基因检测、医疗诊断等领域的应用进展,以期为核酸标准物质的研制提供参考。     

尿素(UREA)血清标准物质的制备及定值

采用新鲜人血为原材料,制备成具有UREA标准浓度(5.32±0.16)mmol/L的血清标准物质,采用分光光度法对此标准物质进行定值,并且对UREA浓度含量进行不确定度评定,均匀性稳定性检验。     

转基因定量检测用质粒分子标准物质研究进展

近10年来,应用于转基因植物产品定量检测的质粒分子标准物质凭借其易于富集,快捷高效等优点,成为各国检测机构的研究热点。对国内外转基因植物核酸定量检测用的质粒分子标准物质研究进展进行总结和评述,并且对该类标准物质在研制过程中的问题进行分析,同时展望了该类标准物质的发展与应用。     

水的饱和辛醇溶液水分标准物质的研制

生物燃料的国家标准规定了产品的技术指标和相应的检测方法。水的饱和辛醇溶液的水分标准物质,用于生物燃料水分测量时仪器的校准和方法的验证,能够保障测量结果的准确可靠和等效一致。该标准物质采用卡尔·费休库仑法、卡尔·费休容量法和定量核磁共振等三种不同原理的方法定值。通过方法研究和改进,实现了库仑法和容量法的一致;通过引入新的核磁共振方法,提高了结果的准确性。最终标准物质的水分量值为4.76％,扩展不确定度为0.09％。     

国内外参考物质管理浅析

参考物质是临床检测参考体系的重要组成部分,可用于实验室间比对,参考方法的验证和溯源链的传递.通过讨论参考物质相关概念,着重介绍了测量不确定度和计量学溯源性等参考物质相关特征属性.结合我国与相关国际机构对参考物质的管理特点,对临床检测使用的参考品进行了概述.     

应用生物效应数据库法建立淡水水体沉积物重金属质量基准

重金属是水体沉积物中的重要污染物,可能对底栖生物和水生态环境产生严重的危害.生物效应数据库法是国际上广泛接受的沉积物质量基准计算方法.本文介绍了利用该方法计算沉积物质量基准的详细过程,并应用该方法初步建立了Cu、Zn、Cd、Pb、Ni 5种重金属的淡水沉积物质量基准,对建立基准值进行了可比性、可靠性和可预测性分析.结果表明: Cd、Ni、Pb、Zn、Cu的临界效应浓度(TEL)分别为3.0、31.4、47.3、74.9和45.5 mg·kg^-1(以干质量计),可能效应浓度值(PEL)为19、76.9、204.1、403.6和181.1 mg·kg^-1(以干质量计).除Zn外,其他4种重金属的TEL、PEL值与其定义的生物效应基本一致,符合针对保护底栖生物制定的沉积物质量基准的要求,具有较高的可靠性,可以作为淡水水体沉积物重金属质量基准建议值.     

海洋微生物天然活性物质的开发应用进展

综合课题研究和国内外文献资料报道概括了海洋微生物及其天然活性物质的开发和应用现状、海洋微生物天然活性物质的研究开发方法及其开发和应用前景。     

关联分析及其在植物中的应用

关联分析是新近开始在植物数量性状研究和植物育种中应用的一种分析方法.它以连锁不平衡为基础鉴定某一群体内性状与遗传标记或候选基因间的关系,是对分子育种中QTL分析的补充和提高.本文在介绍连锁不平衡的定义和度量方法的基础上,讨论连锁不平衡程度和群体结构对关联分析的影响,综述了关联分析在植物方面的研究进展,并最后讨论了关联分析在植物数量性状和分子育种研究中可能的应用.     

上下法在急性毒性试验中的应用进展

随着全球对动物福利的关注,各种传统急性毒性试验的替代方法得到了人们越来越广泛的关注。上下法作为OECD修订发布的急性毒性试验方法之一,是传统急性毒性试验的一个替代方法,有着巨大的应用价值和发展前景。本文简要介绍了该方法的发展历程和在实际应用中的注意事项,评价了上下法与传统方法及其他替代方法相比的优缺点,并综述了近年来该方法在国内外的应用进展。     

Application of Uncertainty Factors in the Priority Substances Program and International Harmonization

The Canadian Environmental Protection Act (CEPA) authorizes the Ministers of the Environment and of Health in Canada to investigate a wide variety of substances that may contaminate the environment and cause adverse effects on the environment and/or on human health. Under the Act, assessments have been completed for 44 environmental contaminants on the first Priority Substances List (PSL) and are relatively advanced for 25 compounds on the second PSL. The principles developed for the application of uncertainty factors in assessment of risks to human health for Priority Substances under CEPA are outlined, with emphasis on those aspects which are somewhat unique and/or evolving. The interface of developments in the Priority Substances program with an initiative of the International Programme on Chemical Safety in this area to effect greater harmonization of approaches is also described.     

When Do Allocations and Constructs Respect Material,Energy, Financial,and Production Balances in LCA and EEIO?

Conservation of mass and energy are essential to physical accounting, just as price and market balances are essential to economic accounting. These principles guide data collection and inventory compilation in industrial ecology. The resulting balanced surveys, however, can rarely be used directly for life cycle assessment (LCA) or environmentally extended input‐output (EEIO) analysis; some modeling is necessary to recast coproductions by multifunctional activities as monofunctional unit processes (a.k.a. Leontief production functions or technical “recipes”). This modeling is done with allocations in LCA and constructs in input‐output. In this article, we ask how these models respect or perturb the balances of the original inventory. Which allocations or constructs, applied to what type of data set, have the potential to simultaneously respect its multiple physical, financial, and market balances? Our analysis builds upon the recent harmonization of allocations and constructs and the ongoing development of multilayered supply and use inventory tables. We derive the necessary and sufficient conditions for balanced models, investigate the role of data aggregation, and clarify these models' relation to system expansion. We find that none of the modeling families in LCA and EEIO are balanced in general, but special data characteristics can allow for the respect of multiple balances. An analysis of these special cases allows for clear guidance for data compilation and methods integration.     

Applying heat and mass balance theory to determine the flow rate for the measurement of benthic material flux in a flow-through system

Movement of water overlying the sediments has not been taken into consideration in most of the experiments conducted to estimate the dissolved material flux from the sediment. Even in recent experiments that incorporated the stirring motion, interpretation of the data is difficult, because the mixing rate used may be different from actual mixing rate in the field. We propose a method to estimate the in situ mixing rate that should be used to set the flow rate in a flow-through core incubation system. The flow rate is calculated from the vertical mixing rate of the water that is deduced from the heat diffusivity. Release rates of NO₃+NO₂–N obtained from our flow-through incubation system were higher by 1–3 orders of magnitude than those from the conventional diffusion calculation method that estimates the flux from the gradient of nutrient concentration across the sediment-water interface. Increase in NO₃+NO₂–N flux is considered to be due to intensification of the nitrification process as a result of an increase in dissolved oxygen (DO) supply with the motion of water. DO supply is also considered to be an important factor controlling macrofaunal abundance and consequently their excretory contributions to the fluxes of dissolved organic nitrogen as well as NH₄–N. From this point of view, we strongly recommend the application of heat and mass balance theory to estimate nitrogen flux using a flow-through experimental system.     

Comprehensive Realism's Weight-of-Evidence Based Distributional Dose-Response Characterization

Challenges to low-dose linearity and other default assumptions in cancer risk assessment and the limitations associated with NOAELs, LOAELs, and constant uncertainty factor values in the evaluation of noncancer health effects have stimulated the continued evolution of risk assessment methodologies. The increasing need for more realistic estimates of the dose-response relationship, better uncertainty characterization, and greater utilization of cost-benefit analyses have also contributed to this evolution. “Comprehensive Realism” is an emerging quantitative weight-of-evidence based risk assessment methodology for both cancer and noncancer health effects which utilizes probability distributions and decision analysis techniques to reflect more of the relevant human exposure data, more of the available and pertinent human and animal dose-response data, and the current state of knowledge about the relative plausibility of alternative dose-response analyses. A tree (like a decision tree and a probability tree) is used to decompose the dose-response assessment into component factors, to provide a structure for explicitly considering multiple alternatives for each factor, and to explicitly incorporate the current state of knowledge about the relative plausibility of these alternatives. Groundbreaking work has demonstrated the feasibility of weight-of-evidence based distributional characterizations, and provided initial examples. Computer software implementations are also available.     

Preparation of a beef-extract as a laboratory reference material for the determination of heterocyclic amines

The present paper describes the preparation of a suitable laboratory reference material (LRM) to validate analytical methods for the determination of heterocyclic amines (HAs) in foods. Three different lots of reference material were prepared using a beef extract which was contaminated with a well-known quantity of amines at different levels ranging from 10 to 75 ng/g. These materials were then lyophilised under determined conditions and, after grinding and sieving, homogenised and, finally, bottled and labelled. Homogeneity and stability studies were performed and no statistical differences were observed in the analysis of variances for within- and between-bottle results, thus demonstrating the homogeneity of the material. Stability at different storage temperatures (-18, +4, +25 and +40 degrees C) and times (1, 2, 3 and 6 months) was also tested. Therefore, the material can be considered homogeneous and stable and can be proposed for use in inter-comparison exercises for the determination of HAs.     

Quantifying the propagation of parametric uncertainty on flux balance analysis

Flux balance analysis (FBA) and associated techniques operating on stoichiometric genome-scale metabolic models play a central role in quantifying metabolic flows and constraining feasible phenotypes. At the heart of these methods lie two important assumptions: (i) the biomass precursors and energy requirements neither change in response to growth conditions nor environmental/genetic perturbations, and (ii) metabolite production and consumption rates are equal at all times (i.e., steady-state). Despite the stringency of these two assumptions, FBA has been shown to be surprisingly robust at predicting cellular phenotypes. In this paper, we formally assess the impact of these two assumptions on FBA results by quantifying how uncertainty in biomass reaction coefficients, and departures from steady-state due to temporal fluctuations could propagate to FBA results. In the first case, conditional sampling of parameter space is required to re-weigh the biomass reaction so as the molecular weight remains equal to 1 g mmol⁻¹, and in the second case, metabolite (and elemental) pool conservation must be imposed under temporally varying conditions. Results confirm the importance of enforcing the aforementioned constraints and explain the robustness of FBA biomass yield predictions.     

Approaches for Quantifying the Metabolism of Physical Economies: Part I: Methodological Overview

This article is the first of a two-part series that describes and compares the essential features of nine existing "physical economy" approaches for quantifying the material demands of the human economy upon the natural environment. A range of material flow analysis (MFA) and related techniques is assessed and compared in terms of several major dimensions. These include the system boundary identification for material flow sources, extents, and the key socioinstitutional entities containing relevant driving forces, as well as the nature and detailing of system components and flow interconnections, and the comprehensiveness and types of flows and materials covered.
Shared conceptual themes of a new wave of physical economy approaches are described with a brief overview of the potential applications of this broad family of methodologies. The evolving and somewhat controversial nature of the characteristics and role that define MFA is examined. This review suggests the need to specify whether MFA is a general metabolic flow measurement procedure that can be applied from micro to macrolevels of economic activity, or a more specific methodology aimed primarily at economy-wide analyses that "map" the material relations between society and nature. Some alternative options for classifying MFA are introduced for discussion before a more detailed comparative summary of the key methodological features of each approach in the second part of this two-part article.
The review is presented (1) as a reference and resource for the increasing number of policy makers and practitioners involved in industrial ecology and the evaluation of the material basis of economies and the formulation of eco-efficiency strategies, and (2) to provoke discussion and ongoing dialogue to clarify the many existing areas of discordance in environmental accounting related to material flows, and help consolidate the methodological basis and application of MFA.     

Enhancing Life-Cycle Inventories via Reconciliation with the Laws of Thermodynamics

Abstract: Obtaining reliable results from life-cycle assessment studies is often quite difficult because life-cycle inventory (LCI) data are usually erroneous, incomplete, and even physically meaningless. The real data must satisfy the laws of thermodynamics, so the quality of LCI data may be enhanced by adjusting them to satisfy these laws. This is not a new idea, but a formal thermodynamically sound and statistically rigorous approach for accomplishing this task is not yet available. This article proposes such an approach based on methods for data rectification developed in process systems engineering. This approach exploits redundancy in the available data and models and solves a constrained optimization problem to remove random errors and estimate some missing values. The quality of the results and presence of gross errors are determined by statistical tests on the constraints and measurements. The accuracy of the rectified data is strongly dependent on the accuracy and completeness of the available models, which should capture information such as the life-cycle network, stream compositions, and reactions. Such models are often not provided in LCI databases, so the proposed approach tackles many new challenges that are not encountered in process data rectification. An iterative approach is developed that relies on increasingly detailed information about the life-cycle processes from the user. A comprehensive application of the method to the chlor-alkali inventory being compiled by the National Renewable Energy Laboratory demonstrates the benefits and challenges of this approach.