Design and use of reference data sets for testing scientific software

A general methodology for evaluating the accuracy of the results produced by scientific software has been developed at the National Physical Laboratory. The basis of the approach is the design and use of reference data sets and corresponding reference results to undertake black-box testing.

The approach enables reference data sets and results to be generated in a manner consistent with the functional specification of the problem addressed by the software. The results returned by the software for the reference data are compared objectively with the reference results. Quality metrics are used for this purpose that account for the key aspects of the problem.

In this paper it is shown how reference data sets can be designed for testing software implementations of solutions to a broad class of problems arising throughout science. It is shown how these data sets can be used in practice and how the results provided by software under test can properly be compared with reference results. The approach is illustrated with three examples: (i) mean and standard deviation, (ii) straight-line fitting, and (iii) principal components analysis. Software for such problems is used routinely in many fields, including optical spectrometry.     

Do we need to accredit proficiency testing schemes?

 Proficiency testing (PT) is being increasingly used as an important quality assurance tool for laboratories. The subject of quality of the providers of PT schemes has been discussed increasingly in recent years. Some countries have implemented systems for the accreditation of PT schemes. This paper looks at the background to the accreditation of PT schemes, the likely mechanisms which could be employed for accreditation, and some of the practical aspects.     

孔加工工序质量控制的研究

本文以孔加工工序为例,运用数理统计方法,吸收 Ｉ Ｓ Ｏ ９０００ 国际标准的管理思想,介绍了改进工序质量的措施     

Quality assessment of localization technique performance in small volume in vivo H MR spectroscopy

A new phantom and evaluation method for experimental evaluation of ¹H-magnetic resonance spectroscopy single volume localization techniques regarding signal contamination (C), defined as the part of the signal originating outside the volume of interest, is presented. The quality assessment method is based on a spherical phantom with an oil/water interface in order to reduce susceptibility effects, and applied for stimulated-echo acquisition method (STEAM) and spin-echo (SE) sequences, echo times of 270, 135, and 10 ms, and cubic volumes of interest (VOI) of 1³, 1.5³, 2³, 2.5³, and 3³ cm³. To be able to mimic measurements of the contamination in three dimensions the physical gradients representing the three orthogonal directions for slice selection were shifted in the pulse sequences. Contamination values in one dimension differed between 6.5% and 8.4% in SE sequences, and between 0.7% and 13.8% in STEAM sequences. In STEAM sequences a decrease of C with increasing VOI size was observed while SE sequences showed comparable C values for the different VOI sizes tested. The total contamination in three dimensions were 19% and 18% in SE and STEAM sequences with a TE of 270 ms, and 7% in a STEAM sequence with a TE of 10 ms, respectively. The presented evaluation method is easily applied to the new phantom and showed high reproducibility.     

Dehydration of hawthorn fruit juices using ultrasound-assisted vacuum drying

In this study, ultrasound-assisted vacuum drying (UAVD) was employed as a new approach to improve the efficiency and produce dried hawthorn fruit juice powders with acceptable quality. To achieve these goals, the effects of ultrasound intensity (at four levels of 15.29, 20.38, 22.93 and 24.46 kW/m²) were evaluated. The results showed that UAVD significantly shortened the drying time (P < 0.05), and with the increasing ultrasound intensity, the drying rate increased and the drying time decreased. Based on statistical tests, the Page model was found to fit well to the drying kinetics. After drying, a decline in quality of fresh juices was observed. As compared with vacuum drying individually, UAVD significantly reduced the colour degradation, and increased the retention of the total flavonoids content, five flavonoid compounds contents and antioxidant activity. It was shown that UAVD at the higher ultrasound intensity varied from of 20.38 to 24.46 kW/m² contributed to a better quality in the dried juice powders. Overall, this study demonstrates that UAVD is a promising technique for improving the drying efficiency and quality retention of hawthorn fruit juices.     

Integration of metabolomics and network pharmacology to validate the mechanism of Schisandra chinensis（Turcz.）Baill - Acorus tatarinowii Schott ameliorating the Alzheimer's disease by regulating the aromatase activity to affect local estrogen in brain of AD model rats

Alzheimer's disease (AD) is a latent and progressive neurodegenerative disease. Schisandra chinensis（Turcz.）Baill - Acorus tatarinowii Schott (Sc-At) are effective in treating neurological disorders.Purpose of this study is to explore the mechanism of Sc-At in AD treatment. First, untargeted ultra-performance liquid chromatography quadrupole-time of flight/mass spectrometer (UPLC-QTOF/MS) metabolomics was employed to detect the rat brain metabolism. Then, network pharmacology was used to determine the potential anti-AD targets. Bioinformatics, and molecular docking were conducted for further analysis. A MetScape study examined the association between differential metabolites and potential targets. Finally, the targeted ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) metabolomics and the potential protein activity studies were carried out to elucidate the mechanisms. The results showed that Sc-At improved the neuronal cell alignment disorder in hippocampal CA1 region of AD rats. In brain metabolomics, 30 differential metabolites were screened in the study model versus blank group. The network pharmacology analyzed 54 targets of Sc-At anti-AD where, 14 were correlated with amyloid β-protein (Aβ). Aromatase was selected as an important hub target having the best binding power in molecular docking simulation predictions and also correlated with Aβ. Further tests showed that the brain aromatase activity, and the downstream product 17β-Estradiol levels were elevated in AD rats treated with Sc-At. This work may provide new perspectives for the pharmacological effects and the action mechanisms of natural compounds extracts in treating AD progression.     

Advances in chromatographic analysis of ginsenosidesEI北大核心CSCD

Ginsenosides possess pharmacological activities such as anti-aging，cardiovascular protection，and improving immunity. However，the detection and analysis of ginsenosides commonly suffer from the problem of low sensitivity owing to the complex matrix and low content of ginsenosides. Chromatographic technology was often used to detect ginsenosides owing to the advantages of high accuracy，high sensitivity，good reproducibility and low sample consumption，etc. In this review，the application of chromatographic analysis technologies in ginsenosides detection was summarized. First of all，accuracy of test results for the ginsenosides can be effectively improved by using high performance liquid chromatography（HPLC）combined with various detectors. Secondly，the combination of HPLC with mass spectrometry can be utilized for qualitative and quantitative analysis of ginsenosides， as well as other fields， such as metabonomics， pharmacokinetics， intestinal microorganisms and quality control. Moreover，the application of gas chromatography in analysis of ginsenosides was reviewed. Briefly，with the continuous development of chromatographic technology，the degree of accuracy for ginsenosides detection was effectively improved，which is beneficial to realize the effective analysis of ginsenosides. © 2023, Youke Publishing Co., Ltd. All rights reserved.     

Bioanalytical method validation,biopharmaceutical and pharmacokinetic evaluation of GSK-650394, a serum- and glucocorticoid-regulated kinase 1 inhibitor

GSK-650394 is an inhibitor of serum- and glucocorticoid-regulated kinase 1 that displays potency for treating cancer, hypertension, cardiovascular and neuronal diseases, such as Parkinson’s disease. However, the biopharmaceutical properties and pharmacokinetics of GSK-650394 have not been studied extensively. Also, there are currently no bioanalytical assays available for this new drug candidate. In this study, we developed a simple and sensitive liquid chromatography-tandem mass spectrometry method to quantify GSK-650394 in rat plasma and validated its selectivity, linearity, accuracy and precision, sensitivity, matrix effects, extraction recovery, and stability, following the United States Food and Drug Administration guidelines. In vitro studies showed the biopharmaceutical properties of GSK-650394, including its low solubility in water and simulated gastrointestinal fluids, passive transport in Caco-2 cell monolayers, high plasma protein binding, and primary metabolism by glucuronide conjugation in the small intestine and liver of rats. Following intravenous administration (2 mg/kg) to rats, GSK-650394 exhibited low total clearance (11.18 ± 1.28 mL/min/kg) and volume of distribution at steady-state (346.1 ± 120.6 mL/kg). Following oral administration (2, 5, and 10 mg/kg) to rats, GSK-650394 underwent enterohepatic circulation, with low bioavailability (～9%). The insignificant difference in bioavailability among three oral doses suggests that GSK-650394 may follow linear pharmacokinetics up to an oral dose of 10 mg/kg. In addition, the total form of parent drug and glucuronide conjugate in rat plasma from three oral doses showed a much higher value of area under the plasma concentration versus time curve than the parent drug, indicating that the primary metabolism process of GSK-650394 was glucuronidation. Our findings suggest that the low oral bioavailability of GSK-650394 is associated with its low solubility, instability under acidic gastric conditions, and extensive glucuronidation metabolism.