Quality assurance and quality control in the laboratory andrology

Quality assurance （QA） and quality control （QC） are fundamental aspects of any laboratory measurement. However, in comparison with other medical disciplines, the need for QA and QC in laboratory andrology has been recognized only recently. Furthermore, there is evidence that the effort required to undertake QA and QC has not been wholly welcomed by some clinicians. Nevertheless, accrediting bodies and regulatory authorities increasingly require evidence that laboratories have effective QA and QC measures in place because both are central to the quality management processes. Following the publication of the 5th edition of the World Health Organization Laboratory Manual, existing QA and QC systems will need to be updated to take into account some of the methodological changes recommended by the manual. Three of these are discussed in this commentary; they relate to： （i） the move to infer semen volume from its weight; （ii） the re-classification of sperm motility grades from four to three; and （iii） the publication of a lower reference limit for morphology of 4% （with a corresponding 95% confidence interval of 3%-4%）. The importance of QA and QC in all laboratory tests, including up and coming new tests to assess sperm DNA integrity, is discussed. The need for adequate initial training and continuing professional development programmes to support laboratory scientists performing andrology is also described.

Application of Statistical Process Control for Setting Action Thresholds as Quality Assurance of Dose Verifications in External Beam Radiotherapy

Purpose: To test the concept of Statistical Process Control (SPC) as a Quality Assurance (QA) procedure for dose verifications in external beam radiation therapy in conventional and 3D Conformal Radiotherapy (3D-CRT) treatment of cervical cancer. Materials and Methods: A study of QA verification of target doses of 198 cervical cancer patients undergoing External Beam Radiotherapy (EBRT) treatments at two different cancer treatment centers in Kenya was conducted. The target doses were determined from measured entrance doses by the diode in vivo dosimetry. Process Behavior Charts (PBC) developed by SPC were applied for setting Action Thresholds (AT) on the target doses. The AT set was then proposed as QA limits for acceptance or rejection of verified target doses overtime of the EBRT process. Result and Discussion: Target doses for the 198 patients were calculated and SPC applied to test whether the action limits set by the Process Behavior Charts could be applied as QA for verified doses in EBRT. Results for the two sub-groups of n = 3 and n = 4 that were tested produced action thresholds which are within clinical dose specifications for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. Conclusion: Action thresholds set by SPC were within the clinical dose specification of ±5% uncertainty for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. So the concept of SPC could be applied in setting QA action limits for dose verifications in EBRT.

Dynamic estimation and reliability control of quality assurance for bored piles

A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the performance of a pile foundation. Its prior distribution and updating distribution were deduced to follow Beta distributions. To calibrate the OPDP, a dynamic estimation model was established according to the relationships between prior mean and variance and updating mean and variance. Finally, a reliability-control method dealing with uncertainties arising from quality assurance inspection was formalized to judge whether all the bored piles from a site can be accepted. It is exemplified that the OPDP can be substantially improved when more definite prior information and sampling formation become available. For the example studied herein, the Bayesian estimator of updating variance for OPDP is reduced from 0.0037 to 0.0014 for the first inspection, from 0.0014 to 0.0009 for the second inspection, and with less uncertainty by incorporating experience information.

Multi-objective quality control method for cold-rolled products oriented to customized requirements

To deal with the increasing demand for low-volume customization of the mechanical properties of cold-rolled products, a two-way control method based on mechanical property prediction and process parameter optimization(PPO) has become an effective solution. Aiming at the multi-objective quality control problem of a company's cold-rolled products, based on industrial production data, we proposed a process parameter design and optimization method that combined multi-objective quality prediction and PPO. This method used the multi-output support vector regression(MSVR) method to simultaneously predict multiple quality indices. The MSVR prediction model was used as the effect verification model of the PPO results. It performed multi-process parameter collaborative design and realized the optimization of production process parameters for customized multi-objective quality requirements. The experimental results showed that, compared with the traditional single-objective quality prediction model based on support vector regression(SVR), the multi-objective prediction model could better take into account the coupling effect between process parameters and quality index, the MSVR model prediction accuracy was higher than that of the SVR, and the optimized process parameters were more capable and reflected the influence of metallurgical mechanism on the quality index,which were more in line with actual production process requirements.

A Spatial Consistency Quality Control Method for Daily Surface Temperature Observations

Based on the spatial regression test (SRT) and random forest (RF), a new spatial consistency quality control method named SRF was adapted to identify potential outliers in daily surface temperature observations in this article. For the new method, the SRT method was used to filter the data and the RF method was used to conduct regression. To evaluate the performance of the quality control method, the SRF, SRT and RF methods were applied to a surface temperature dataset with seeded errors from different regions of China from 2005 to 2014. The results indicate that the SRF method outperforms the other two methods in most cases. And the results of the comparison led to the conclusion that the SRF method improves the regression accuracy of traditional spatial consistency quality control methods and reduces the runtime of random forest through data refinement.

ARMA-GM combined forewarning model for the quality control

Three forecasting models are set up: the auto\|regressive moving average model, the grey forecasting model for the rate of qualified products P t, and the grey forecasting model for time intervals of the quality catastrophes. Then a combined forewarning system for the quality of products is established, which contains three models, judgment rules and forewarning state illustration. Finally with an example of the practical production, this modeling system is proved fairly effective.

Development and Challenge of HIV/AIDS Testing Laboratory Network and Quality Assurance System in China

This paper describes the development and challenge of HIV/AIDS testing laboratory network and quality assurance system in China. At present,the HIV/AIDS testing laboratories includes three classes,the National AIDS Reference Laboratory,HIV/AIDS confirmatory laboratories and HIV/AIDS screening laboratories. All of them are accredited by the health authorities,and each class of laboratories take charge of their function strictly according to the "National Management of HIV/AIDS Detection (2006)". A complete quality assurance and quality control system for HIV/AIDS testing has been developed,which includes technical training,strict laboratory monitoring and approval,examination or proficiency testing on HIV/AIDS detection,and quality evaluation and supervision of HIV/AIDS diagnostic kits. Besides conduct the routine anti-HIV antibody test,more and more laboratories began to conduct other tests,such as CD4+ T lymphocyte cell counting,HIV viral load,HIV DNA PCR,genotyping,drug resistance,and HIV-1 recent infection test. The primary challenges faced by the HIV/AIDS testing laboratory network are in the areas of laboratory management and quality control. For example,the provincial PT program is inefficient,the internal quality control is conducted perfunctorily,personnel training can not met the needs of the workplace,which need to be improved.

Replacing liquid fyrite with digital to improve <i>in vitro</i>fertilization laboratory quality control procedures

In clinical in vitro fertilization (IVF), optimal culture conditions are required for production of high quality embryos and for achieving high pregnancy rates. Cell culture systems require vigilant attention to quality control and quality assurance, and upgrades to equipment and procedures require strenuous deliberation. During a 2-week maintenance period, we undertook an extensive analysis of incubator carbon dioxide (CO2) monitoring and the effect on culture media pH by comparing our traditional liquid Fyrite instruments to a certified and calibrated digital CO2 analyzer. The digital analyzer produced consistently lower CO2 readings and significantly greater precision than the liquid Fyrite. Media pH measurements showed significant variation depending on CO2 calibration device;however pH remained within manufacturers’ specifications. After superior performance by the digital analyzer, we incorporated this device into the incubator calibration and daily quality control procedures. A retrospective comparison of overall lab performance before and after this equipment switch demonstrated improved clinical pregnancy and implantation rates. This report illustrates the necessary caution when altering established laboratory procedures and equipment while highlighting the benefits of judiciously updating techniques and equipment in a laboratory setting that is often stubborn to change pre-existing, ingrained methodology.

Influence of quality assurance on patients dose reduction in some hospitals

The radiation dose received by patients undergoing chest radiography was included. 200 patients who attended these investigations in 10 hospitals in Iran were randomly selected from all ages groups and both female and male. Critically ill patients were excluded.This paper presents the work, which was implemented on 200 patients and evaluated using the entrance skin dose (ESD) in the posterior anterior (PA) chest projection measured directly at the center of the X-ray field. In addition, the machine room, and dark room parameters, as well as work practices and repeat rates were studied. The quality control (QC) parameters and the ESD before and after QC were evaluated utilizing an anthropomorphic phantom to define the optimal exposure condition at all hospitals. This research shows that after using the QC parameters and after optimization of the exposure conditions, the ESD was decreased by 42% on average. Also the quality of the radiographs generally increased. The reported method is easily implemented in any clinical situation where optimization of chest radiography is needed.

Study on Factors Influencing the Quality of Automatic Monitoring Data of Pollution Sources and Technical Assurance Measures

Automatic monitoring data of pollution sources is an important basis for environmental supervision and management.At present,it is difficult to guarantee the quality of automatic monitoring data of pollution sources,and it is difficult to play the role of the monitoring data.In response to this problem,the factors influencing the quality of automatic monitoring data of pollution sources were analyzed in detail,and technical assurance measures for the quality of automatic monitoring data of pollution sources in Shandong Province were studied.Besides,the dynamic management and control idea of automatic monitoring of pollution sources was proposed,and specific technical measures were analyzed from five aspects of standardizing automatic monitoring equipment of pollution sources,improving the data collection and transmission system,establishing a mechanism for reporting operating status information of monitoring equipment,setting alarm rules and alarm processing procedures,and statistically analyzing the operating status of the equipment.Practice has proved that the dynamic management and control system can effectively ensure the quality of automatic monitoring data of pollution sources.

Partial Quality Assessment of ⁶⁰Co-Teletherapy Machine Performance

The aim of this study was to assess the performance of 60Co-teletherapy unit at Radiation and Isotopes Center in Khartoum, using the common tools used for quality control (Front pointer, Graphic paper, Pin, Non-screen film, meter and Check plate). The collected and analyzed data revealed that: there was a difference between the calculated theoretical field size (FS) and the measured one relative to the change of SSD;and the average FS shift was 0.9 cm relative to the standard one, while the machine isocenter was almost fixed at 0° with a shift of 0.003 cm, which was within the standard limit (0.2 cm). The diaphragm isocenter showed a shift of ±0.36 cm (i.e. in clock and anti clock wise) in average relative to standard limit (±0.3 cm) and the couch vertical isocenter (CVI) relative to the SSD changes was exceeded the standard limit (0.2 cm) by a factor of 0.9 cm. Also the SSD determined by the optical distance indicator was greater than the actual SSD (determined by Front pointer and measured by scale meter) by an average of 0.8 cm;which exceeded the limit (0.3 cm) by an average factor of 0.5 cm. The study also showed that the penumbra profile (1.5 cm) was less than the actual specified for 60Co-teletherapy machine, while the radiation beam was so homogeneous across the field size.

Research on Factors Affecting Boiler Feedwater Quality and Its Improvement

Nowadays, with the rapid progress and development of the Chinese society, people’s material level has been continuously improved, and the demand for electricity has also been increasing year by year. For thermal power plants, it is of great importance to strictly control the feedwater quality and to conduct real-time tracking and supervision, as well as to ensure the safety of the production process. In this paper, we take the boiler feedwater quality in the production process as the research object. First of all, the cause-and-effect diagram is used to find out the reasons for the deviation of feedwater quality;Secondly, each index of feedwater is analyzed by multiple linear regression method to find out the key variables affecting the change of its pH value, so as to develop and implement improvement measures;Finally, the pH value is compared and verified by control chart and process capability analysis, and relevant improvement suggestions and countermeasures are proposed.

Top-down法评定EDTA络合滴定法测定海洋沉积物中碳酸钙含量的不确定度

依据Top-down技术中的质控图法对EDTA络合滴定法测定海洋沉积物中碳酸钙含量的不确定度进行评定。利用2021年质控样标准物质GBW 07333、GBW 07314和GBW 07316中CaCO_(3)测定值的时序数据进行评定,3组时序数据正态统计量A^(2*)(s)和独立性统计量A^(2*)(RM)均小于1,CaCO_(3)测定值、A_(EWMi)和移动极差控制图没有失控点,3组时序数据处于受控状态。当CaCO_(3)质量分数分别为2.05%、6.20%和38.56%时,计算得其扩展不确定度分别为0.08%、0.07%和0.20%。将测量不确定度与对应含量值进行线性拟合建立了不确定度预测模型,GBW 07309和GBW 07334中CaCO_(3)的测量不确定度预测值分别为0.09%和0.18%,预测值与Top-down技术获取的评定结果较为吻合。

债务融资对终极股东行为影响的实证分析——基于内部控制质量的门限效应和调节效应

集中股权结构的上市公司中,终极股东对其他中小股东有一定的利益侵害动机,债务融资作为公司治理的一个重要环节,研究其对终极股东行为的影响是一个值得探究的问题。以我国523家非金融类上市公司2007-2022年的面板数据为样本,考虑内部控制质量的门限效应与调节效应,实证检验了债务融资对终极股东掏空行为的促进或抑制效应。研究发现:(1)银行债务、商业信用和长期债务对终极股东掏空行为具有显著的促进效应;当内部控制质量分别大于门限值860.160、873.700、873.700时,此类效应减弱;(2)短期债务对终极股东掏空行为具有显著的抑制效应;当内部控制质量大于门限值873.700时,此效应得到加强;(3)商业信用、长期债务、银行债务对于国有企业中终极股东掏空行为的促进效应,受到内部控制质量的反向调节。研究结论为上市公司制定健全的内部治理环境策略以及为债权人制定合理的借贷策略从而促进上市公司高质量发展提供了参考依据。

水生生物监测质量保证、质量控制与标准化:动态与展望

水生生物监测是流域水生态状况评价的重要基础,监测数据的准确性和可靠性直接影响水生态环境质量评价与流域水生态管理成效。目前我国水生生物监测质量保证和质量控制体系尚处于持续完善的阶段,关键环节的控制要求和质控目标等亟待明确和细化。本文总结了欧美发达国家水生生物监测质量保证与质量控制体系建设中的经验,通过梳理我国水生生物监测工作基础与进展,较为系统地提出了适合我国现状的水生生物监测质量保证与质量控制体系标准化建设对策建议,包括实验室内部和外部质量保证与质量控制、水生生物监测质控数据库、人工智能识别和环境DNA新技术质控要点等标准化建议,为实现水生生物监测业务化运行,准确评估我国流域水生态质量状况的变化提供技术支撑。

国外地质勘查与资源调查评价中样品分析质量保证与质量控制的实践

文章总结了质量保证与质量控制(Quality Assurance/Quality Control, QA/QC)在地质勘查和资源调查评价样品分析中的意义,根据最佳工业实践,推荐质控样品的插入率≥20%。对质控样品的选择与评价方法进行总结,标准样品应与待测样品基体匹配且含量范围涵盖整个待测样品的含量水平,标准样品的测试结果使用控制图进行准确度判断;重复样品应在每一个重要的采样、制样阶段进行采集,并且应随机选取,重复样品的分析结果通过散点图判断精密度是否达到预期设定界限,通过相对偏差图可以获得不同因素对精密度的影响,国际上通用的量化重复样品精密度的方法是计算变异系数(Coefficient of Variation, CV);空白样品的目标元素含量应低于检出限,实验室空白样品一般为高纯度的石英砂,实际的资源勘查项目中也可采集野外空白样品进行污染监控,空白样品的控制限为3~5倍方法检出限;外检样品应送到级别相当或更高的实验室进行检测,判断两个实验室测量结果的差异,外检样品选择应随机,通过散点图判断外检样品结果的可靠性。文章通过国际上资源调查评价中质量控制与质量保证的实例进行总结,与国际标准对标,对于今后海外找矿,海外资源调查评价有重要作用。

用多酚类指标表征干红葡萄酒味感质量的模型构建

采用葡萄酒多酚系列指标,构建味感质量预测模型,实现干红葡萄酒涩感和余味的客观量化。试验以宁夏和新疆的50款赤霞珠干红葡萄酒为原料,利用常规方法检测样品总酸、挥发酸和pH值,采用自由基清除法测定抗氧化活性,通过紫外-可见分光光度计法分析总酚、花色苷、黄烷醇、黄酮醇、酒石酸酯含量,并以感官品评法量化干红葡萄酒的涩感和余味。相关性分析结果显示,总酚、花色苷、黄烷醇、黄酮醇等对涩感和余味的影响有显著差异(P<0.05),酒石酸酯对余味的影响较小,而总酸和pH值对供试干红葡萄酒的涩感没有显著影响(P>0.05)。感官品评量化结果显示,宁夏和新疆产区酒样的涩感得分为6.18和5.70,余味得分为5.37和4.85,供试酒样的涩感与余味质量良好,且存在相似的变化趋势。以多酚系列指标表征的涩感质量偏最小二乘回归(partial least squares regression,PLSR)模型的决定系数(r-square,R^(2))为0.83,余味模型的R^(2)为0.78,结果表明,总酚、黄烷醇、挥发酸、DPPH等指标对葡萄酒的涩感和余味贡献较大,黄酮醇和酒石酸酯主要影响葡萄酒的涩感,而花色苷、总酸和pH值则主要影响葡萄酒余味。研究得出,基于紫外-可见分光光度计法设计的多酚系列指标可以较好地解析干红葡萄酒的味感质量,降低检测成本,具备表征和预测干红葡萄酒味感质量的能力。

溢价预期对农户绿色防控技术采纳行为的非线性影响:基于质量认证的视角

绿色防控技术推广是应对气候变化和实现农业绿色转型的重要举措。现有研究往往单独分析溢价预期和质量认证对农户绿色防控技术采纳行为的影响,忽视了农户在溢价预期的激励下主动参与质量认证的可能性和溢价预期的作用程度。本文构建“溢价预期—质量认证—绿色防控技术采纳行为”的分析框架,利用湖北省1039户水稻种植户调研数据,探究溢价预期对农户绿色防控技术采纳行为的影响以及质量认证在其中的内在机制。结果显示:第一,溢价预期总体上显著促进了农户的绿色防控技术采纳行为,但溢价预期的促进效应呈现边际效应递减的非线性特征。而且,溢价预期对种植规模小、满足口粮型农户的绿色防控技术采纳行为的促进作用更强。第二,溢价预期与农户参与质量认证存在“倒U”型关系,即溢价预期对质量认证的影响具有“预期动力不足—溢价预期释放—溢价预期牵制”的非线性变化轨迹。第三,机制分析表明,溢价预期高的农户可以通过参与质量认证间接促进其采纳绿色防控技术。因此,有必要完善绿色农产品市场体系以强化农户对优质优价的信心,优化质量认证发展环境和配套措施吸纳农户广泛参与质量认证,实现对农户采纳绿色防控技术的长效激励。

地理环境因子对民航飞行“接地距离远”超限事件影响分析

“15 m(50 ft)至接地距离远”是民航客机在着陆阶段常发生的超限事件。研究机场地理环境因子对该超限事件的影响,能够为机场选址和飞行品质评估提供参考依据。使用飞机快速存储记录器(QAR)数据、机场的地形和气象数据,通过全局和局部相关性分析,确定“接地距离远”事件的主要地理环境影响因子;基于地理加权回归模型,建立“接地距离远”事件频率与高程、起伏度以及气温之间的回归模型;根据回归系数,采用Kmeans聚类算法将因子的影响模式分为五类,探究地理环境因子对“接地距离远”事件影响的空间格局及作用机制。结果表明:“接地距离远”事件频率与高程、起伏度、气压和气温有显著的相关性,各因子对“接地距离远”事件的影响强度和方向存在明显的空间分异现象,同一影响模式下的机场在空间分布上呈现出聚集性。