Study on the quantitative structureactivity relation-ship of C-10 substituted artemisinin (QHS)’s derivatives using rough set theory

The structure-activity relationship study of C-10 substituted artemisinin (QHS) derivatives that are used as antimalarial was performed with the RS (rough sets) method. An RS process is a concise nonlinear process, and it has broad application foreground in the data mining of nonlinear life courses. In this work, initially the parameters of C-10 substituted QHS’s derivatives were computed with the quantum chemistry method, and the information table was constructed from the parameters (condition attributes) and biological activity (decision attributes). Based on the analysis of rough set theory, the core and reduction of attributes sets were obtained. Then the decision rules were extracted and the struc-ture-activity relationship was analyzed. As a nonlinear system, RS theory can extract the special rela-tion in the database. It has the advantage of being nonlinear over multiple linear regression (MLR), principal component analysis (PCA), partial least square (PLS), etc., and the advantage of obtaining results with unambiguous physical meanings over artificial neuron networks (ANNs), etc. The result obtained in this study is instructive to the study of pharmacodynamics, resistance mechanism of QHS and development of QHS’s derivatives.     

2D-QSAR Using MLR and 3D-QSAR Using CoMSIA Studies on the Toxicity of Aromatic Hydrocarbons on Larval Sinonvaculina Constricta

Aromatic hydrocarbons,one of the persistent organic pollutants(POPs),has been usually found in mussels,accumulated for their hard mobility and activities in harbours and estuaries.In this study,based on the 96 hr-LC50 of 12 aromatic hydrocarbons with larval sinonvaculina constricta,three-dimensional quantitative structure-activity relationship(3D-QSAR) technique:comparative molecular similarity indices analysis(CoMSIA) and 2D-QSAR technique:multiple linear regression(MLR) were described to obtain more detailed insight into the structure-activity relationships between the molecular structure and bio-activity.The results show the MLR model based on density functional theory(DFT) calculation carried out at the B3LYP/6-311** level with Gaussian 03 program yielded a very good correlation with a coefficient squared R2 of 0.716 and a cross-validated Q2 of 0.874.The dipole moment and enthalpy,as the thermodynamic parameters,were two important factors influencing pLC50.Correspondingly,CoMSIA based on the partial least-squares(PLS) methodology with steric,electrostatic,hydrophobic,H-bond donor and acceptor fields contributing simultaneously were employed and the values of R2 and the cross validation with leave-One-Out(LOO) Q2LOO were 0.585 and 0.990,respectively,which reveals the structure features,such as the electronegative substituent(nitro-group),hydrophobic groups(the benzene ring) and H-bond(nitro-group),related to the toxicity.The results of 2D-QSAR employing MLR model and 3D-QSAR employing CoMSIA model provide the useful information for predicting the toxicity of other aromatic hydrocarbons by comparing the molecular structures of similar compounds.     

Quantitative Analysis of Catalpol in Chinese Patent Medicine Lixin Pill by Near-infrared Diffuse Reflectance Spectroscopy

Lixin pill is a typical Chinese patent medicine with anti-rheumatic heart disease activity that has been widely used in clinical practice. Therefore it is very important to detect the concentration of catalpol, as the main component of the active ingredient. Near-infrared reflectance（NIR） spectroscopy was used to study the content of catalpol in the unprocessed Chinese patent medicine of Lixin pills. NIR is applied to quantitatively analyze 77 sam- ples, which were randomly divided into a calibration set containing 61 samples and a prediction set containing 16 samples. To get a satisfying result, partial least squares（PLS） regression was utilized to establish quantitative models. In PLS regression, the values of coefficient of determination（R2） and root mean square error of cross-validation （RMSECV） of PLS regression are 0.9419 and 0.0216, respectively. The process of establishing model, parameters of model, and prediction results were also discussed in detail（root mean square error of prediction is 0.0164）. The over- all results show that NIR spectroscopy can be efficiently utilized for the rapid and accurate analysis of routine chemical compositions in the Chinese patent medicine of Lixin pills. The prediction set suggests that this quantitative analysis model has excellent generalization ability and prediction precision. Accordingly, the result can provide tech- nical support for the further analysis of catalpol in unprocessed Lixin pill. Moreover, this study supplied technical support for the further analysis of other Chinese patent medicine samples.     

The effect of cation size (H+, Li+, Na+, and K+) on McLafferty-type rearrangement of even-electron ions in mass spectrometry

Protonation and alkali-metal cation adduction are the most important ionization processes in soft-ionization mass spectrometry.Studies on the fragmentation mechanism of protonated and alkali-metal-cationized compounds in tandem mass spectrometry are essential and helpful for structural analysis.In some cases,it was often observed that a compound attached by different alkali-metal cations(or proton)exhibits similar fragmentation patterns but the relative abundances of product ions are different.This difference was considered to derive from the different electrostatic interactions of alkali-metal cations(or the bonded effect of proton)with the analyte.The alkali-metal cation with a smaller ionic radius shows stronger electrostatic interaction with the molecule because of its higher charge density.In addition,the bonded effect of the proton is stronger than the electrostatic interaction of the alkali-metal cation.In the present study,which used McLafferty-type rearrangements of even-electron ions([M+Cat]+,Cat=H,Li,Na,K)as model reactions,the effect of cation size in mass spectrometric fragmentation reactions is highlighted.These considerations were also successfully applied to interpret the similar but distinct fragmentation behavior of proton and alkali-metal cation adducts of a synthetic compound(2-(acetamido(phenyl)methyl)-3-oxobutanoate)and a drug(entecavir).     

THE SENSITIVITY OF RESPONSE SIGNAL OF SPECTROELECTROCHEMISTRY(SEC)

In this paper, we propose the use of the molar absorbance/potential ratio to measure quantitatively the sensitivity of response signalof SEC cell and the system under study. A simple equation was developed, andthe major factors influencing the sensitivity were also assessed. Theresults obtained this way were in good agreement with actual cases.     

Composition determination of binary polymer mixtures by size exclusion chromatography with light scattering detection

<正>Base on the principle of absolute quantification of size exclusion chromatography(SEC),a light scattering(LS) detector coupled with a concentration detector(refractive index detector) is utilized to determine the compositions of complicated binary mixtures.A theoretical analysis predicts that the response factors for both LS and RI detectors are linear functions with the composition of any specified polymer mixtures in the binary polymer mixtures.Two pairs of complicated binary mixtures were used to test the theory mentioned in the present paper,and the experimental results show an excellent accordance with the theory.     

QSAR for Predicting Biodegradation Rates of Polycyclic Aromatic Hydrocarbons in Aqueous Systems

The relationship between chemical structures and biodegradation rates (k b) of 22 polycyclic aromatic hydrocarbons (PAHs) was studied using density functional theory (DFT) and stepwise multiple linear regression analysis (SMLR) method.The equilibrium geometries and vibration frequency have been investigated at the B3LYP/6-31+G(d,p) level by thinking Solvent effects using a selfconsistent reaction field (SCRF) based on the polarizable continuum model (PCM).It was concluded that the biodegradation rate was closely related to its molecular structure,and there is one high correlation coefficient between the in-plane bending vibration frequency of the conjugated ring of PAHs (Freq) and k b.By means of regression analysis,the main factors affecting the biodegradation rate were obtained and the equation of quantitative structure-activity relationship (QSAR) was successfully established kb =-0.653+0.001Freq+0.068CQ+0.049N1.Statistical evaluation of the developed QSAR showed that the relationships were statistically significant and the model had good predictive ability.The fact that a bending frequency is more important than the HOMO or LUMO energies in predicting k b suggests that the bending of benzene ring might play an important role in the enzymatic catalysis of the initial oxidation step.     

Age-dependent logistic regression model and its application

In the present paper we introduce the theory and algorithm of the unconditional and conditional age-dependent logistic regression model, which combines logistic regression analysis of case-control study with survival analysis of cases in the data, thus facilitating simultaneous comparison analysis between cases and controls and among cases with different ages of disease onset under study. In age-dependent logistic regression analysis, estimated compound relative risk (CRR) and compound attributable risk (CAR) comprise the variance contributions of risk factors to disease occurrence and the time of disease onset, thereby the role played by various risk factors in etiology and etiopathology can be objectively evaluated. The current logistic regression model is only a particular case of age-dependent logistic regression theory neglecting the variations in onset age of diseases.     

妇科患者泌尿生殖道支原体属感染的高危因素研究

目的调查分析妇科患者泌尿生殖道支原体属感染的高危因素。方法选取2014年1月—2015年10月于孝感市中心医院妇科进行诊治的950例泌尿生殖道感染的患者为研究对象,将其泌尿生殖道支原体属感染的发病率进行统计,比较支原体属感染的患者不同年龄段、民族、职业、文化程度、孕产史、是否伴有淋病感染、不洁性史、性交次数过多等因素的发生率及构成比,并行Logistic回归分析。结果 1 950例泌尿生殖道感染的患者中有320例患者为支原体属感染,发病率为33.68%。其中21~40岁年龄段、无职业、文化程度较低、孕产次数较多、伴有淋病感染、具有不洁性史及性交次数过多的患者较其他患者发病率普遍较高,以上差异均具有统计学意义(P0.05)。2经Logistic回归分析发现,伴有淋病、不洁性史与性交次数过多为支原体属感染的独立危险因素(P0.05),而年龄、文化程度及孕产史也与支原体属感染密切相关(P0.05)。而民族、职业无明显相关性(P0.05)。结论淋病、不洁性史、性交次数过多、年龄、文化程度及孕产史均为妇科患者泌尿生殖道支原体属感染的高危因素,可根据以上因素进行针对性干预以降低支原体属的泌尿生殖道感染率。     

超声心动图诊断胎儿先心病及危险因素分析

本研究探讨超声心动图在胎儿先心病诊断中的价值以及影响先心病发病的危险因素。采用回顾性研究方法,选取孕产妇18987例,均进行系统的彩色多普勒超声检查,同时问卷调查胎儿先心病家庭65例(病例组)及130例正常胎儿家庭(对照组)的病史等情况。结果显示,先心病发病率为0.43%,疾病类型中:以单纯性室间隔缺损、心内膜垫缺损和右心室双出口为主;Logistic回归分析结果显示:产妇年龄、孕期有致畸物接触史、产妇糖尿病、产妇结缔病、不良妊娠史、染色体异常、胎儿早期NT值、先心病家族史是先心病发生的影响因素(P<0.05)。从上述结果可知,超声心动图在胎儿先心病诊断中有较好的价值,先心病发病受产妇年龄、致畸物接触史等因素的影响。     

混料回归法测定三元络合物组成比方法的研究

本文提出了一种新的测定多元络合物组成的方法——混料回归法。与其它测定多无络合物组成的方法比较,可减少实验次数,且不需绘图。用本文方法测定Cu-phen-CAS三元络合物的组成比,其结果与连续变化法及文献结果一致。经验证,该法应用简便,结果准确。     

复方局部缓释性药物治疗牙周病的临床效果分析

目的研究并分析治疗牙周病时使用复方局部缓释性药物的效果。方法收集牙周炎患者共74例,根据随机化分组原则分为对照组(37例)和观察组(37例),对照组接受常规治疗,观察组接受复方局部缓释性药物治疗,将两组患者的疗效、相关致病菌总数进行观察和对比。结果观察组疗效显著高于对照组,观察组相关致病菌总数显著低于对照组,P均0.05。结论在牙周炎患者的治疗过程中,复方局部缓释性药物能够使患者获得更佳疗效,减少致病菌,抑制病情发展,值得推广应用。     

Nonlinear regression checking via local polynomial smoothing with applications to thermogravimetric analysis

A goodness‐of‐fit test statistic for nonlinear regression models based on local polynomial estimation is proposed in this paper. The criterion used to construct the test is the distance between the parametric fit and the nonparametric regression estimation. The good performance of the test is shown via a simulation study. The method is applied to check a logistic mixture regression model for real data coming from a thermal analysis problem. Copyright © 2009 John Wiley & Sons, Ltd.     

Oscore: a combined score to reduce false negative rates for peptide identification in tandem mass spectrometry analysis

Tandem mass spectrometry (MS/MS) has been widely used in proteomics studies. Multiple algorithms have been developed for assessing matches between MS/MS spectra and peptide sequences in databases. However, it is still a challenge to reduce false negative rates without compromising the high confidence of peptide identification. In this study, we developed the score, Oscore, by logistic regression using SEQUEST and AMASS variables to identify fully tryptic peptides. Since these variables showed complicated association with each other, combining them together rather than applying them to a threshold model improved the classification of correct and incorrect peptide identifications. Oscore achieved both a lower false negative rate and a lower false positive rate than PeptideProphet on datasets from 18 known protein mixtures and several proteome-scale samples of different complexity, database size and separation methods. By a three-way comparison among Oscore, PeptideProphet and another logistic regression model which made use of PeptideProphet's variables, the main contributor for the improvement made by Oscore is discussed.     

Simulation study for generalized logistic function in thermal data modeling

The principal aim of the present study is to describe, analyze, and compare from a statistical standpoint the generalized logistic model with some well-known models used in the solid-state kinetics: power law, Avrami–Erofeev, and reaction order. For this purpose, synthetic conversion curves that simulate the kinetic processes were generated using the power law, Avrami–Erofeev, and reaction order models, where the Arrhenius equation was assumed in all the cases. This comprehensive simulation study allows to describe the relationship between the parameters belonging to the proposed generalized logistic model and the pointed traditional models’ parameters, and also to validate the performance of the generalized logistic model in a wide variety of cases where other methods can be applied. Performing this analysis has been necessary to employ some new statistical techniques in thermal analysis modeling as the generalized additive models, and to perform global optimization evolutionary algorithms as the differential evolution for solving the non-linear regression problem. In order to implement these techniques, R statistical software routines were developed and applied.