Novel evaluation method of biodegradabilities for oil-based polycaprolactone by naturally occurring radiocarbon-14 concentration using accelerator mass spectrometry based on ISO 14855-2 in controlled compost

The biodegradabilities of poly(?-caprolactone) (PCL) powders (av. size = 180.7 μm) in controlled compost at 58 °C have been studied using the microbial oxidative degradation analyzer (MODA) based on ISO 14855-2 entitled “Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions - Method by analysis of evolved carbon dioxide - Part 2: Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test”. The biodegradability of the PCL powders was 101.4% in a 56-day test period by the ISO method. The biodegradabilities of PCL powders have been studied using percent modern carbon (pMC) measured by accelerated mass spectrometry (AMS). Trapped CO₂ was analyzed by AMS to determine the pMC (sample) using ¹⁴C radiocarbon concentration. By using the theory that the pMC (sample) was the sum of pMC (compost) (104.88%) and pMC (PCL) (0%) as the respective ratios in the determined period, CO₂ (respiration) was calculated only from one reaction vessel. The biodegradability of PCL powders was 79.9% in a 56-day test period by the AMS method. It was found that respiration activities in the sample vessel including PCL, compost and sea sand were the same as that in the blank vessel including compost and sea sand without PCL during the active biodegradation period (0-33 day) at 58 °C. It was confirmed that respiration activities in the sample vessel were slightly higher than that in the blank vessel after active biodegradation due to the propagation of microorganisms using energy and metabolites by PCL biodegradation during those periods.     

Evaluation of the Coulomb energy in relativistic self-consistent-field theory

 Computational schemes are presented with which to evaluate the electrostatic Coulomb energy in relativistic molecular electronic structure calculations using a basis of four-component Dirac spinor amplitudes. We demonstrate that algorithms may be constructed and implemented which differ only in minor details from those in common use in nonrelativistic quantum chemistry, and that the four-component formalism is neither as complicated nor as expensive as has been suggested recently in the literature. Spherically symmetrical atomic basis sets are presented which indicate that accurate representations of the Coulomb energy may be obtained using modest expansions of the electronic density in a scalar auxiliary basis set of spherical harmonic Gaussian-type functions. Received: 15 April 2002 / Accepted: 15 May 2002 / Published online: 29 July 2002     

Advanced statistical evaluation of the complex formation constants from electrophoretic data II: Diastereomeric ion-pairs of (R,S)-N-(3,5-dinitrobenzoyl)leucine and tert-butylcarbamoylquinine

Intermolecular association and ion-pair formation, respectively, between a cationic chiral selector, viz. o-9-(tert-butylcarbamoyl) quinine (CQN), and the both enantiomers of anionic N-(3,5-dinitrobenzoyl)leucine, (R)-DNB-Leu and (S)-DNB-Leu, were investigated by affinity capillary electrophoresis (ACE). Thus, binding constants of the both diastereomeric ion-pairs, (R) and (S)-DNB-Leu/CQN associates, were determined by different experimental setups and correction of nonlinear effects. A reciprocal setup was employed for the high-affinity (S)-enantiomer, and the experimental mobility data obtained for CQN at variable (S)-DNB-Leu concentrations in the background electrolyte were linearized and evaluated by advanced statistical model. A binding constant of K_S=125.1 l mol⁻¹ was afforded. The constant for the (R)-enantiomer, which is outside the range suitable for direct affinity CE, was obtained from indirect affinity CE utilizing the separation of the DNB-Leu racemate at a single appropriate CQN concentration in the BGE (resolution method) taking advantage of the known constant for the (S)-enantiomer yielding a binding constant of K_R=2.51 l mol⁻¹. Thereby, the so-called “constant time method” was adopted for the required precise measurement of the effective mobilities of the both enantiomers. A combined approach of reciprocal affinity CE with racemic DNB-Leu as additive and the resolution method confirmed the results. The resulting constants evidence excellent enantioselectivity of the tert-butylcarbamoyl derivative of the cinchona alkaloid quinine as chiral selector for N-(3,5-dinitrobenzoyl) derivatives of amino acids.     

A study for quality evaluation of Taxilli Herba from different hosts based on fingerprint-activity relationship modeling and multivariate statistical analysis

In this study, a fingerprint-activity relationship modeling between chemical fingerprints and antirheumatic activity was established, and multivariate statistical analysis was used to evaluate the quality of Taxilli Herba (TH) from different hosts. Characteristic fingerprints of 20 batches of TH samples were generated by high-performance liquid chromatography coupled with triple quadrupole-time of flight tandem mass spectrometry (HPLC-Triple TOF-MS/MS), and the similarity analysis was calculated based on thirteen common characteristic peaks by hierarchical clustering analysis (HCA). Subsequently, nine efficacy markers were discovered by combining fingerprints and antirheumatic activity through grey correlation analysis (GCA) and bivariate correlation analysis (BCA). Meanwhile, the content of 5 constituents in 9 markers was determined by high-performance liquid chromatography coupled with triple quadrupole-linear ion trap tandem mass spectrometry (HPLC-QTRAP-MS/MS). The comprehensive quality of TH was assessed using multivariate statistical analysis, including principal components analysis (PCA) and technique for order preference by similarity to ideal solution (TOPSIS). The results showed that a high dose of TH extract could markedly ameliorate arthritis damage compared to other doses, with flavonoids playing an important role in the antirheumatic activity. The comprehensive quality of samples from Morus alba L. (SS) was superior to those from Liquidambar formosana Hance (FXS). The present study will demonstrate the markers associated with efficacy, and provide an applicable strategy for more comprehensive quality control and evaluation of TH.     

Error Levels of Different Methods of Evaluation of TG Measurements

It follows from an analysis of the error levels of TG evaluation methods that it is a conceptual error to disregard the analogies of mass, energy and momentum streams of subordinate partial processes. This error is bypassed by means of the introduced method of dimensionless analysis and by determining the characteristic, constants-like data of thermal processes by using the measured data directly. These methods are very suitable for increasing the consistency of the calculated results by seeking for similarity, even in comparisons of measurements made under very different conditions and for emphasizing the differences too, quantitatively. With this new interpretation of TG processes, the idea of the kinetic compensation effect becomes only a consequence of the discussed conceptual error. This revised version was published online in August 2006 with corrections to the Cover Date.     

Qualitative evaluation of aromatic herbs by direct headspace GC analysis. Applications of the method and comparison with the traditional analysis of essential oils

GC headspace analyses of various aromatizing herbs have been compared with those relating to the essential oils, obtained by steam distillation, of the same plants. In this way it was possible to establish the most significant differences between the composition of a herb flavor and that of its essential oil. In particular, we observed some very volatile compounds in the headspace samples which were absent from the essential oil; these components may make an important contribution to the herb flavor. The identification of these substances is still in progress.     

基于最小各向同性小波滤波的图像清晰度识别

提出了基于最小各向同性小波滤波的图像清晰度识别方法,对二维最小各向同性小波滤波提取图像特征进行了研究.直接将原始图像通过带通小波滤波器G0获得图像边缘信息,结合图像能量分析,建立了基于小波滤波的图像清晰度评价函数.利用构建的显微镜自动对焦实验平台,比较分析了基于小波滤波和拉普拉斯的评价方法.实验结果表明,采用基于各向同性小波滤波的自动对焦算法有更好的综合自动对焦性能.     

桑白皮中21种无机元素的测定及其质量评价

为准确了解不同产区桑白皮中多种元素分布及含量情况,用65%硝酸溶液对其样品进行微波消解处理,后采用电感耦合等离子体质谱（ICP-MS/MS）法测定桑白皮样品中21种元素的含量。得到21种元素的线性关系良好,R2 > 0.999,方法学考察试验的RSD均小于3%,加样回收率在91.32%~108.84%之间,RSD均小于4%;Al、Ga、Sr、Ba相比而言含量较大,且不同产区的特异性较明显;主成分分析中17批样品得到4个主成分,累计方差贡献率达 87.380%,确定V、Co、Al、Li、As、Se、Pb、U、Zn、Cr、Cd、Ga、Ba、Cs、Ni等15种元素为桑白皮药材的特征元素;相关性分析可知,元素间的相关性较强, P≤0.05的元素与主成分分析的特征元素基本一致。参照2020年版《中国药典》中对中药材中有害元素的限量规定,发现桑白皮样品中Pb、Cd、As、Cu有害元素的含量均未超过限量要求。ICP-MS/MS能准确快速测定桑白皮中21种元素含量情况,这对评价不同产区桑白皮质量,完善桑白皮质量标准具有一定参考价值。     

基于化学计量学结合ICP-MS的党参道地性的研究及安全评价

微量元素与中药的功效和安全性密切相关,也是药材道地性研究的一部分,为探讨党参中重金属元素的安全性、风险性及道地性的相关性。本文采用电感耦合等离子体质谱法（ICP-MS）及原子荧光光谱法(AFS)测定来源于甘肃、山西、湖北、四川等产区的39批党参药材中的20种元素的含量,结果结合化学计量学分析对党参产区进行差异判别。通过单因子污染指数法和内梅罗综合污染指数法对其进行安全性评价,通过健康风险基于暴露量、危害指数法和暴露限值法对其进行风险评估。结果表明,重金属在各自范围内线性关系良好,加样回收率,仪器精密度和重复性良好,其中 Ba、Sr、Mn的含量最高。主成分分析显示39批药材分为三类,同一产区的党参能较好的聚在一起,元素含量差异与产区分布有一定规律,其中Cs、Ga、As、Co、Li、Pb、Hg、Se、V、Mn为关键的差异标志物,为产地元素特征分析鉴别提供依据。安全评价结果为39批党参药材污染等级为安全,但风险评估后DS-31、DS-32、DS-34、DS-36及 DS-37在人体长期蓄积中具有健康风险。结论：本研究方法高效、准确、简便,结合化学计量学可以对党参进行有效的产地判别,评价党参中元素的安全性及风险性,为党参道地性及健康评价提供了科学依据。     

基于模糊评价的学生综合素质挖掘方法

运用数据挖掘思想,运用模糊数学中的综合评判方法对学生信息管理系统中的学生成绩进行挖掘,得到学生综合素质分类,为教育管理中运用数据挖掘这一前沿信息技术提供了示例。