Selecting parameters and limits for equipment operational qualification

While operational qualification (OQ) is a well-established term within equipment qualification, users of equipment often become unsure when it comes to implementation. The biggest problem is how to select procedures and acceptance criteria. Should these be the vendor's specifications or should the users define their own limits, and, if so, how? Should all instruments of the same type have the same values or should these be optimized for each individual instrument? This article will provide an overall strategy and specific examples for HPLC on how to select procedures and acceptance limits that are based on efficient use of resources, on practicality and on the intended use of the equipment.     

Unraveling the mystery of efficacy in Chinese medicine formula: New approaches and technologies for research on pharmacodynamic substances

Traditional Chinese medicine (TCM) is the key to unlock treasures of Chinese civilization. TCM and its compound play a beneficial role in medical activities to cure diseases, especially in major public health events such as novel coronavirus epidemics across the globe. The chemical composition in Chinese medicine formula is complex and diverse, but their effective substances resemble “mystery boxes”. Revealing their active ingredients and their mechanisms of action has become focal point and difficulty of research for herbalists. Although the existing research methods are numerous and constantly updated iteratively, there is remain a lack of prospective reviews. Hence, this paper provides a comprehensive account of existing new approaches and technologies based on previous studies with an in vitro to in vivo perspective. In addition, the bottlenecks of studies on Chinese medicine formula effective substances are also revealed. Especially, we look ahead to new perspectives, technologies and applications for its future development. This work reviews based on new perspectives to open horizons for the future research. Consequently, herbal compounding pharmaceutical substances study should carry on the essence of TCM while pursuing innovations in the field.     

Comparison of particle size and flow rate optimization for chromatography using one-monomer molecularly imprinted polymers versus traditional non-covalent molecularly imprinted polymers

The dependence of enantio-selective chromatographic performance on particle size, as measured by separation factor, was investigated for one-monomer molecularly imprinted polymers (OMNiMIPs) compared to traditionally formed EGDMA/MAA molecularly imprinted polymers (MIPs). Five particle size ranges were compared (<20 μm, 20-25 μm, 25-38 μm, 38-45 μm, and 45-63 μm), revealing that the particle sizes above 25 μm provided the highest separation factor, and thus the best enantiomer separation, for both imprinted polymers. Other chromatographic parameters such as the number of theoretical plates and resolution exhibited only minor changes for the OMNiMIPs as the particle size changed, except for particles 20 μm and below. However, the number of theoretical plates and resolution for EGDMA/MAA are higher for particles in the 20-25 μm range. Thus, chromatographic factors for the EGDMA/MAA polymers are better in this range, despite better enantioselectivity for particle sizes above 25 μm. In contrast, OMNiMIPs generally show the most favorable performance for particle sizes in the 38-45 μm range. It was also found that decreasing flow rate resulted in improved enantioselectivity for both MIPs for all particle sizes.     

反馈调节的局部正则化鲁棒光流估计

提出了一种引入反馈调节机制的新局部鲁棒光流场计算思想.该思想结合局部法和全局法的特点,首先划分整场为有公共边界的子块,定义距离来判断每个点的子块归属,然后在每个子块内进行光流约束和平滑约束正则化的优化计算.将光流约束中的光强残差作为控制参量,衡量光流准确度的峰值信噪比作为输出,经反馈处理,调节控制参量使光流估计准确度趋向最优.实验结果表明,这种新的结合反馈调节机制局部光流场计算法能使光流准确度获得提升.     

高效液相色谱法和硫氰酸钾滴定法检测煤中氯的比较研究

比较了测定煤中氯的高效液相色谱(HPLC)法和硫氰酸钾滴定法。以密闭氧弹燃烧或艾氏卡剂熔融分解样品，分别以高效液相色谱法和硫氰酸钾滴定法测定煤中氯，通过对国家标准物质GBW11118、GBW11119、GBW11120分析结果的比较及t检验，表明两方法无显著性差异。     

Numerical investigation of the physics of rotating-detonation-engines

Rotating-detonation-engines (RDE’s) represent an alternative to the extensively studied pulse-detonation-engines (PDE’s) for obtaining propulsion from the high efficiency detonation cycle. Since it has received considerably less attention, the general flow-field and effect of parameters such as stagnation conditions and back pressure on performance are less well understood than for PDE’s. In this article we describe results from time-accurate calculations of RDE’s using algorithms that have successfully been used for PDE simulations previously. Results are obtained for stoichiometric hydrogen–air RDE’s operating at a range of stagnation pressures and back pressures. Conditions within the chamber are described as well as inlet and outlet conditions and integrated quantities such as total mass flow, force, and specific impulse. Further computations examine the role of inlet stagnation pressure and back pressure on detonation characteristics and engine performance. The pressure ratio is varied between 2.5 and 20 by varying both stagnation and back pressure to isolate controlling factors for the detonation and performance characteristics. It is found that the detonation wave height and mass flow rate are determined primarily by the stagnation pressure, whereas overall performance is closely tied to pressure ratio. Specific impulses are calculated for all cases and range from 2872 to 5511 s, and are lowest for pressure ratios below 4. The reason for performance loss is shown to be associated with the secondary shock wave structure that sets up in the expansion portion of the RDE, which strongly effects the flow at low pressure ratios. Expansion to supersonic flow behind the detonation front in RDE’s with higher pressure ratios isolate the detonation section of the RDE and thus limit the effect of back pressure on the detonation characteristics.     

Novel metrics and methodology for the characterisation of 3D imaging systems

The modelling, benchmarking and selection process for non-contact 3D imaging systems relies on the ability to characterise their performance. Characterisation methods that require optically compliant artefacts such as matt white spheres or planes, fail to reveal the performance limitations of a 3D sensor as would be encountered when measuring a real world object with problematic surface finish. This paper reports a method of evaluating the performance of 3D imaging systems on surfaces of arbitrary isotropic surface finish, position and orientation. The method involves capturing point clouds from a set of samples in a range of surface orientations and distances from the sensor. Point clouds are processed to create a single performance chart per surface finish, which shows both if a point is likely to be recovered, and the expected point noise as a function of surface orientation and distance from the sensor. In this paper, the method is demonstrated by utilising a low cost pan-tilt table and an active stereo 3D camera. Its performance is characterised by the fraction and quality of recovered data points on aluminium isotropic surfaces ranging in roughness average (Ra) from 0.09 to 0.46 µm at angles of up to 55° relative to the sensor over a distances from 400 to 800 mm to the scanner. Results from a matt white surface similar to those used in previous characterisation methods contrast drastically with results from even the dullest aluminium sample tested, demonstrating the need to characterise sensors by their limitations, not just best case performance.     

Separation and Detection of Arsenic and Selenium Species in Environmental Samples by HPLC-ICP-MS

A method is presented for arsenic speciation analysis of an oyster sample using ion chromatography coupled with an inductively coupled plasma mass spectrometry (ICP-MS) instrument. A strong anion exchange resin was employed with a step gradient elution of 0.1 mM/0.1 M K 2 SO 4 at pH 10.2. Arsenobetaine and dimethylarsinic acid were determined following extraction based on trypsin enzymolysis with 95-100% extraction efficiency. Limits of detection in the range 0.1-0.3 mg kg m 1 of arsenic were obtained for organic arsenic species. No inorganic arsenic was detected. Validation was performed using TORT-2 as a certified reference material. Although high performance liquid chromatography (HPLC) coupled to ICP-MS is an effective method for speciation analysis it is not always necessary to obtain such a detailed picture. A simple liquid chromatographic separation technique based upon mini-column technology is presented. It was developed to obtain a fast, efficient and reliable separation of inorganic from organic, i.e. assumed toxic from non-toxic, arsenic and selenium species suitable for use as an initial screening method for environmental analysis. Two types of strong anion exchange resin were tested. Excellent separation was obtained for both min-column resins and analysis times were within 7 min. Limits of detection obtained for inorganic arsenic, organic arsenic, selenomethionine, Se IV and Se VI were 1.6, 1.8, 66, 32 and 22 µg kg m 1 , respectively.     

带连续变利率风险模型最终破产概率上界

考虑了带二元连续变利息力的Sparre Andersen风险模型.研究了积累值盈余过程的表达式与性质;在利率递增环境下,利用推广后的调节系数方程组与递归技术推导了最终破产概率的上界,结论表明得到的破产概率上界是更为一般的Lundberg指数上界.