期刊文献+
共找到3,524篇文章
< 1 2 177 >
每页显示 20 50 100
Mediating role of physical activity in the relationship between psychological distress and intimate relationships among stroke patients 被引量:1
1
作者 Chang-Yue Luo Peng Jiao +2 位作者 Shu-Min Tu Lin Shen Yong-Mei Sun 《World Journal of Psychiatry》 SCIE 2023年第12期1096-1105,共10页
BACKGROUND Stroke patients often experience psychological distress,which can impact their intimate relationships with spouses,subsequently influencing their treatment and recovery.Physical activity is considered a key... BACKGROUND Stroke patients often experience psychological distress,which can impact their intimate relationships with spouses,subsequently influencing their treatment and recovery.Physical activity is considered a key rehabilitation method for stroke patients.This paper aims to analyze whether psychological distress affects intimate relationship between spouses through physical activity.AIM To explore the mediating effect of physical activity between psychological distress and intimate relationship in stroke patients.METHODS A total of 256 stroke patients who underwent treatment at the First People’s Hospital of Shangqiu between July 2021 and July 2022 were enrolled in this study.The participants completed questionnaires,including the Kessler Psychological Distress Scale(K10),the Quality of Relationship Index(QRI),International Physical Activity Questionnaire,and a general information questionnaire.Data analysis were performed using SPSS 23.0.The Harman test was employed to detect common method deviations,and Spearman correlation was used for correlation analysis.The mediating effect was assessed using Process 3.4.1,with significance testing of the regression coefficients conducted using the bias-corrected percentile Bootstrap method(5000 iterations,95%confidence interval).Statistical significance was set at P<0.05.RESULTS The results showed that patients scored an average of 21.61±6.44 points on the K10,32.40±6.19 points on the QRI;the median physical activity level according to the International Physical Activity Questionnaire was 1861(566,2846)MET·min/w.The level of physical activity(the physical activity intensity of the patients reflected by the Interna-tional Physical Activity Questionnaire-Long Form scale)negatively correlated with psychological distress and intimacy(P<0.05),and positively correlated with each other(P<0.05),with the correlation stronger at lower physical activity levels compared to higher ones.The mediating effect of physical activity between psychological distress and intimate relationship was calculated to be 40.23%.Bootstrap analysis further validated the results.The mediating effect of psychological distress on intimate relationships through physical activity level was-0.284,with a confidence interval of-0.409 to-0.163,excluding 0,confirming a significant mediating effect of psychological distress on intimate relationships.CONCLUSION Physical activity significantly affects relationship between psychological distress and intimate relationships among stroke patients.Addressing the role of physical activity may have implications for improving patient outcomes and rehabilitation strategies. 展开更多
关键词 STROKE Cross-sectional study Psychological distress Intimate relationship Mediating effect Physical activity level
下载PDF
Studies on the Synthesis, Anticonvulsant Activity, and the Structure-Activity Relationships of Phenyl Pyridazinones and their GABA Derivatives
2
作者 徐萍 王书玉 刘维勤 《Journal of Chinese Pharmaceutical Sciences》 CAS 1992年第2期27-34,共8页
In searching for effective anticonvulsant agents,fourteen 6-aryl-4.5-di- hydro-3(2H)pyridazinones.fifteen 6-aryl-3(2H)pyridazinones,and seventeen 3-GABA derivatives of 6-aryIpyridazines have been synthesized,and evalu... In searching for effective anticonvulsant agents,fourteen 6-aryl-4.5-di- hydro-3(2H)pyridazinones.fifteen 6-aryl-3(2H)pyridazinones,and seventeen 3-GABA derivatives of 6-aryIpyridazines have been synthesized,and evaluated in mice for the ability to antagonize maximal electroshock seizure(MES).The ED_(50) values showed that 6-(2′,4′- dichlorophenyt)-3(2H)pyridazinone was the most potent anticonvulsant among these corn- pounds(ED_(50)=10.15 mg/kg).The structure-activity relationships of the aryl pyridazinones were studied.The result showed that:(1)the higher the value of the hydrophobic parameter л of the substituent on the phenyl ring.the more potent the anticonvulsant activity of the corn- pound.and(2)only the compounds with an electron withdrawing substituent on the phenyl ring exhibited appreciable anticonvulsant activity. 展开更多
关键词 Aryl pyridazinones 3-GABA-6-aryl pyridazines Anticonvulsant activity Structure-activity relationships
下载PDF
Tuning Active Metal Atomic Spacing by Filling of Light Atoms and Resulting Reversed Hydrogen Adsorption-Distance Relationship for Efficient Catalysis 被引量:3
3
作者 Ding Chen Ruihu Lu +11 位作者 Ruohan Yu Hongyu Zhao Dulan Wu Youtao Yao Kesong Yu Jiawei Zhu Pengxia Ji Zonghua Pu Zongkui Kou Jun Yu Jinsong Wu Shichun Mu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第10期151-162,共12页
Precisely tuning the spacing of the active centers on the atomic scale is of great significance to improve the catalytic activity and deepen the understanding of the catalytic mechanism,but still remains a challenge.H... Precisely tuning the spacing of the active centers on the atomic scale is of great significance to improve the catalytic activity and deepen the understanding of the catalytic mechanism,but still remains a challenge.Here,we develop a strategy to dilute catalytically active metal interatomic spacing(d_(M-M))with light atoms and discover the unusual adsorption patterns.For example,by elevating the content of boron as interstitial atoms,the atomic spacing of osmium(d_(Os-Os))gradually increases from 2.73 to 2.96?.More importantly,we find that,with the increase in dOs-Os,the hydrogen adsorption-distance relationship is reversed via downshifting d-band states,which breaks the traditional cognition,thereby optimizing the H adsorption and H_2O dissociation on the electrode surface during the catalytic process;this finally leads to a nearly linear increase in hydrogen evolution reaction activity.Namely,the maximum dOs-Os of 2.96?presents the optimal HER activity(8 mV@10 mA cm^(-2))in alkaline media as well as suppressed O adsorption and thus promoted stability.It is believed that this novel atomic-level distance modulation strategy of catalytic sites and the reversed hydrogen adsorption-distance relationship can shew new insights for optimal design of highly efficient catalysts. 展开更多
关键词 ELECTROCATALYSIS DFT calculation Interstitial filling Hydrogen evolution Structure–activity relationships
下载PDF
Molecular characteristics and structure–activity relationships of food-derived bioactive peptides 被引量:15
4
作者 YANG Fu-jia CHEN Xu +6 位作者 HUANG Mu-chen YANG Qian CAI Xi-xi CHEN Xuan DU Ming HUANG Jian-lian WANG Shao-yun 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2021年第9期2313-2332,共20页
Peptides are functional active fragments of proteins which can provide nutrients needed for human growth and development,and they also have unique physiological activity characteristics relative to proteins.Bioactive ... Peptides are functional active fragments of proteins which can provide nutrients needed for human growth and development,and they also have unique physiological activity characteristics relative to proteins.Bioactive peptides contain a great deal of development potential.More specifically,food-derived bioactive peptides have the advantages of a wide variety of sources,unique structures,high efficiency and safety,so they have broad development prospects.This review provides an overview of the current advances regarding the preparation,functional characteristics,and structure–activity relationships of food-derived bioactive peptides.Moreover,the prospects for the future development and application of food-derived bioactive peptides are discussed.This review may provide a better understanding of foodderived bioactive peptides,and some constructive inspirations for further research and applications in the food industry. 展开更多
关键词 food-derived proteins bioactive peptides molecular characteristics structure–activity relationship
下载PDF
Determination of structure-activity relationships between fentanyl analogs and human μ-opioid receptors based on active binding site models 被引量:3
5
作者 Ming Liu Xiaoli Liu +2 位作者 Ping Wan Qiangsan Wu Wenxiang Hu 《Neural Regeneration Research》 SCIE CAS CSCD 2011年第4期267-276,共10页
Fentanyl is a potent and widely used clinical narcotic analgesic, as well as a highly selective IJ-opioid agonist. The present study established a homologous model of the human μ-opioid receptor; an intercomparison o... Fentanyl is a potent and widely used clinical narcotic analgesic, as well as a highly selective IJ-opioid agonist. The present study established a homologous model of the human μ-opioid receptor; an intercomparison of three types of μ-opioid receptor protein sequence homologous rates was made. The secondary receptor structure was predicted, the model reliability was assessed and verified using the Ramachandran plot and ProTab analysis. The predictive ability of the CoMFA model was further validated using an external test set. Using the Surflex-Dock program, a series of fentanyl analog molecules were docked to the receptor, the calculation results from Biopolymer/SitelD showed that the receptor had a deep binding area situated in the extracellular side of the transmembrane domains (TM) among TM3, TM5, TM6, and TMT. Results suggested that there might be 5 active areas in the receptor. The important residues were Asp147, Tyr148, and Tyr149 in TM3, Trp293, and His297 in TM6, and Trp318, His319, Ile322, and Tyr326 in TM7, which were located at the 5 active areas. The best fentanyl docking orientation position was the piperidine ring, which was nearly perpendicular to the membrane surface in the 7 TM domains. Molecular dynamic simulations were applied to evaluate potential relationships between ligand conformation and fentanyl substitution. 展开更多
关键词 μ-opioid receptor fentanyl analogs AGONIST active site structure-activity relationship
下载PDF
Numerical Simulation of the Relationship between the Anomaly of Subtropical High over East Asia and the Convective Activities in the Western Tropical Pacific 被引量:40
6
作者 黄荣辉 卢里 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1989年第2期202-214,共13页
In this paper, a close relationship between the intraseasonal variation of subtropical high over East Asia and the convective activities around the South China Sea and the Philippines is analysed from OLR data.This re... In this paper, a close relationship between the intraseasonal variation of subtropical high over East Asia and the convective activities around the South China Sea and the Philippines is analysed from OLR data.This relationship is studied by using the theory of wave propagating in a slowly varying medium and by using a quasi-geoslrophic, linear, spherical model and the IAP-GCM, respectively. The results show that when the SST is warming around the western tropical Pacific or the Philippines, the convective activities are intensified around the Philippines. As a consequence, the subtropical high will be intensified over East Asia. The computed results also show that when the anomaly of convective activities are caused around the Philippines, a teleconnection pattern of circulation anomalies will be caused over South Asia, East Asia and North America. 展开更多
关键词 OVER Numerical Simulation of the relationship between the Anomaly of Subtropical High over East Asia and the Convective activities in the Western Tropical Pacific Asia
下载PDF
Advances in Research of Biological Activity,Action Mechanism and Structure-Activity Relationship of Lentinan
7
作者 Jiawen LI Chao ZHAO +2 位作者 Xiaojian GONG Huaguo CHEN Xin ZHOU 《Asian Agricultural Research》 2023年第12期28-38,共11页
Lentinula edodes is the second largest edible mushroom in the world and is widely used as food and medicine.Modern research shows that lentinan(LNT)is the main active component of L.edodes.It has anti-cancer,treatment... Lentinula edodes is the second largest edible mushroom in the world and is widely used as food and medicine.Modern research shows that lentinan(LNT)is the main active component of L.edodes.It has anti-cancer,treatment of diabetes,intestinal protection,anti-inflammatory,anti-oxidation,anti-aging,hepatoprotective,immune-regulating effects.In this review,the biological activity,action mechanism and structure-activity relationship of LNT in recent years are reviewed.On this basis,the existing problems were discussed,and the future research and application of LNT were prospected.Finally,it is hoped that this review will promote the in-depth study of LNT and provide a reference for its development as a drug and functional food. 展开更多
关键词 LENTINAN BIOLOGICAL activities Action mechanism STRUCTURE-activITY relationship
下载PDF
On quantitative structure-activity relationships between hydrazine derivatives and β irradiation
8
作者 Ling-Yu Wang Yan Wang +4 位作者 Da-Qing Cui Song-Tao Xiao Xiao-Dong Liu Ying-Gen OuYang Cong Huang 《Nuclear Science and Techniques》 SCIE CAS CSCD 2018年第5期36-43,共8页
In this study, solutions of hydrazine and its derivatives were irradiated using a pulsed electron beam to determine the half-reaction time of radiolysis. 3 D structures of the hydrazine derivatives were optimized, and... In this study, solutions of hydrazine and its derivatives were irradiated using a pulsed electron beam to determine the half-reaction time of radiolysis. 3 D structures of the hydrazine derivatives were optimized, and their energies were calculated using density functional theory with the B3 LYP method and 6-311 +(3 d, 3 p) basis set.For the first time, the 3 D quantitative structure-activity relationship(QSAR) equation describing the relationship between the hydrazine derivative structures and rate of radiolysis has been established using SPSS software.Pearson correlation analysis revealed a close correlation between the total energies of the molecules and half-reaction times. In the QSAR equation, Y =-7583.464 +54.687 X_1+94333.586 X_2,Y,X_1,and X_2 are the half-reaction time, total energy of the molecule, and orbital transition energy, respectively. The significance levels of the regression coefficients were 0.006 and 0.031, i.e., both less than 0.05. Thus, this model fully explains the relationship between hydrazine derivatives and β radiolysis stability.The results show that the total energy of the molecule and orbital transition energy are the main factors that influence the β radiolysis stability of these hydrazine derivatives. 展开更多
关键词 HYDRAZINE DERIVATIVES βIrradiation RADIOLYSIS stability QUANTITATIVE structure–activity relationships
下载PDF
Report for Investigating the Relationship between Human activities and Environment
9
作者 孙皓天 《区域治理》 2018年第41期43-44,共2页
It is well established that environmental pollutions are most popular topics recendy and the factor of that is a dominant element that is worth to investigate to large extent.According to lots of human performance so ... It is well established that environmental pollutions are most popular topics recendy and the factor of that is a dominant element that is worth to investigate to large extent.According to lots of human performance so far,negative human activities are like to be a vital driving force of pollutions in some cases.Therefore,the relationship between environment and negative human performance should be researched,which can give better methods to protect natural environment. 展开更多
关键词 NEGATIVE human activities relationship POLLUTION ENVIRONMENTAL conditions
下载PDF
Structure-activity relationships regarding the antioxidant effects of the flavonoids on human erythrocytes
10
作者 Yousif Y. Bilto Sanaa Suboh +1 位作者 Talal Aburjai Shtywy Abdalla 《Natural Science》 2012年第9期740-747,共8页
The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The followin... The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The following flavonoids;quercetin, rutin and morin significantly protected eryt-hrocytes against lipid peroxidation caused by H2O2. This inhibition of lipid peroxidation could be explained by the presence of at least two hydroxyl groups in ring B of the flavonoid structure, regardless of their positions. However, the flavonoids;quercetin, 3,5,7-trihy- droxy-4'-methoxy flavone-7-rutinoside and 3- hydroxy flavone significantly protected eryt-hrocytes against protein degradation. This inhibition could also be explained by the presence of a hydroxyl group at C-3 in ring C of the flavonoid structure. Quercetin and 3,5,7-trihydroxy-4'- methoxy flvone-7-rutinoside significantly protected erythrocytes against loss of deformability and increased osmotic fragility, indicating that the loss of erythrocyte deformability and the increase in osmotic fragility of erythrocytes exposed to H2O2 are related to protein degradation rather than to lipid peroxidation. The other flavonoids (chrysin, 2-carboxy ethyl dihydroxy flavone, apigenin, cirsimaritin, α-naphto flavone and flavanone) failed to protect erythrocytes against the observed oxidative damages. The results demonstrate the importance of the chemical groups substituted on the basic skeleton of the flavonoids in dictating the type of antioxidant activity, and also demonstrate the hemorheological potentials of flavonoids that have particular protein-antioxidant activities. 展开更多
关键词 ERYTHROCYTE DEFORMABILITY LIPID PEROXIDATION Protein Degradation Oxidative Stress H2O2 FLAVONOIDS STRUCTURE-activITY relationships
下载PDF
Quinoline-based anti-MRSA agents: Current development, structure-activity relationships, and mechanisms
11
作者 Hong Yao Liping Cui +5 位作者 Hang Liu Xueyu Li Lin Shen Ruige Yang Shangshang Qin Yong Guo 《Chinese Chemical Letters》 SCIE CAS CSCD 2024年第1期52-63,共12页
Methicillin-resistant Staphylococcus aureus (MRSA), the most common pathogen in hospital and community environments, can cause serious and even fatal infections. The antibiotics currently used for clinical treatment o... Methicillin-resistant Staphylococcus aureus (MRSA), the most common pathogen in hospital and community environments, can cause serious and even fatal infections. The antibiotics currently used for clinical treatment of MRSA have developed resistance, and there is an urgent need to develop new antimicrobials to treat infections caused by MRSA strains. Quinoline analogues play an important role in the development of antimicrobials. Herein, we discussed the current development of antibacterial activities of quinoline analogues, mainly for anti-MRSA activity, and their structure-activity relationships (SARs) from the perspective of using the quinoline nucleus to search for novel potential anti-MRSA candidates. Additionally, the mechanisms of some representative quinoline analogues against MRSA were clarified. Altogether, this review could provide further insights for the rational development of quinoline-based antibacterial drugs, especially against MRSA. 展开更多
关键词 Quinoline analogue Methicillin-resistant Staphylococcus aureus Antibacterial activity Structure–activity relationship Antibacterial mechanism
原文传递
Chalcone derivatives as novel,potent and selective inhibitors against human Notum:Structure–activity relationships and biological evaluations
12
作者 Jin-Hui Shi Bei Zhao +7 位作者 Li-Lin Song Yu-Qing Song Meng-Ru Sun Tian Tian Hong-Yu Chen Yun-Qing Song Jian-Ming Sun Guang-Bo Ge 《Chinese Chemical Letters》 SCIE CAS CSCD 2024年第3期321-325,共5页
Human Notum(hNotum)inhibitors could be used for treating Wnt signalling-associated diseases including colorectal cancer.Herein,two series of chalcone derivatives were designed and synthesized aiming to find selective ... Human Notum(hNotum)inhibitors could be used for treating Wnt signalling-associated diseases including colorectal cancer.Herein,two series of chalcone derivatives were designed and synthesized aiming to find selective and potent hNotum inhibitors.Structure–activity relationship(SAR)studies showed that 2-methoxyl and 5-bromine substitutions on A-ring significantly enhanced anti-hNotum effect,while 4’-ethoxyl and 3’-alkyl substitutions on B-ring were beneficial for hNotum inhibition.Among all tested chalcones,B11 displayed the most potent anti-Notum effect(IC_(50)=3.6 nmol/L),good selectivity,excellent chemical stability and suitable metabolic stability.Further investigations showed that B11 acted as a competitive inhibitor of hNotum,while this agent(5μmol/L)significantly weaken the migration abilities of colorectal cancer cells.Collectively,this study deciphers the SARs of chalcones as hNotum inhibitors and reports a novel and potent hNotum inhibitor with the anti-migration effect on colorectal cancer cells,which offers a promising lead compound to develop novel anti-cancer agents. 展开更多
关键词 Human notum(hNotum) CHALCONE Computer-assisted drug discovery Structure–activity relationship(SAR) Anti-colorectal cancer agent
原文传递
The Relationship between Dali Lord Worship Ritual Activity and Regional Landscape Architecture in China
13
作者 文晨 陈一 《Journal of Landscape Research》 2011年第9期88-91,共4页
The paper had introduced Lord Worship ritual activity unique to Bai Nationality and analyzed Dali landscape characteristics from the aspects of landscape pattern, architectural courtyard pattern and plants landscaping... The paper had introduced Lord Worship ritual activity unique to Bai Nationality and analyzed Dali landscape characteristics from the aspects of landscape pattern, architectural courtyard pattern and plants landscaping. In the perspective of surface, line and spot landscape architectures, Lord Worship ritual activity had been analyzed. It had revealed that the development of Lord Worship ritual activity was rooted in local landscape environment, and temple's site selection, square construction, activities' route selection and construction of forest land in front of residences were all based on landscape environment. After the analysis of the relationship between Lord Worship ritual activity and landscape places, it had opened a new thought for researches on religious activities and regional landscape. It could explore and recover some traditional folk cultures when environmental landscapes had been studied, so as to promote the inheritance of national culture. 展开更多
关键词 LORD WORSHIP RITUAL activITY Landscape ARCHITECTURE relationship
下载PDF
Quantitative Structure-activity Relationship Study on the Antioxidant Activity of Carotenoids 被引量:2
14
作者 孙玉敬 庞杰 +2 位作者 叶兴乾 吕元 李俊 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2009年第2期163-170,共8页
Carotenoids are a family of effective active oxygen scavengers, which can reduce the danger of occurrence of chronic diseases such as cardiovascular disease, cataract, cancer, and so on. The quantitative structure-act... Carotenoids are a family of effective active oxygen scavengers, which can reduce the danger of occurrence of chronic diseases such as cardiovascular disease, cataract, cancer, and so on. The quantitative structure-activity relationship (QSAR) equation between carotenoids and antioxidant activity was established by quantum chemistry AM1, molecular mechanism (MM+) and stepwise regression analysis methods, and the model was evaluated by leave-one-out approach. The results showed that the significant molecular descriptors related to the antioxidant activity of carotenoids were the energy difference (E_HL) between the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) and ionization energy (Eiso). The model showed a good predictive ability (Q^2 〉 0.5). 展开更多
关键词 quantitative structure-activity relationship antioxidant activity carotenoids
下载PDF
Spatial Structure of Urban Residents’ Leisure Activities: A Case Study of Shenyang, China 被引量:2
15
作者 MA Liya XIU Chunliang 《Chinese Geographical Science》 SCIE CSCD 2021年第4期671-683,共13页
The spatial characteristics of residents’ leisure activities not only reflect their demand for urban leisure space but also affect the urban spatial layout. This study takes Shenyang, China as an example and analyzes... The spatial characteristics of residents’ leisure activities not only reflect their demand for urban leisure space but also affect the urban spatial layout. This study takes Shenyang, China as an example and analyzes the characteristics of residents’ leisure activities through questionnaires. On this basis, it uses point of interest data and mobile phone signaling data to identify various types of residential and leisure functional relationships, and uses spatial analysis and community detection to assess the distance characteristics, flow patterns, and community structure of residents’ leisure activities, so as to discuss the spatial structure of residents’ leisure activities in Shenyang. The results showed that: (1) in addition to leisure at home, Shenyang residents mainly went to shopping malls, supermarkets,and parks for leisure activities, and the proportions of residents of the two types of leisure activities were approximately equal;(2) the average distances that residents traveled for shopping and park leisure were near in the middle and far in the periphery, and the travel costs of peripheral residents for centrally located leisure were higher than those for residents in central areas;(3) the flow patterns of the residential-shopping and residential-park functional relationships displayed clustering mode characteristics, and Shenyang presented a significant monocentric structure;and (4) residents’ shopping activities were concentrated in the southern community, and walking in the park activities were concentrated in the western community. Residents’ leisure activities were characterized by centripetal agglomeration,which was prone to problems such as traffic congestion and big city diseases. The spatial expansion process in the city was characterized by obvious directional inheritance and path dependence, and the construction of sub-cities is needed to improve the related service facilities. 展开更多
关键词 leisure activities travel distance residential-shopping functional relationship residential-park functional relationship community detection
下载PDF
Quantitative Structure-activity Relationship Studies on the Antioxidant Activity and Gap Junctional Communication of Carotenoids 被引量:1
16
作者 孙玉敬 吴丹 +3 位作者 刘东红 陈健初 沈妍 叶兴乾 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2010年第9期1362-1372,共11页
The antioxidant and gap junctional communication(GJC) activities of carotenoids are known to be the two main anticancer mechanisms.Quantitative structure-activity relationship(QSAR) models of the two activities we... The antioxidant and gap junctional communication(GJC) activities of carotenoids are known to be the two main anticancer mechanisms.Quantitative structure-activity relationship(QSAR) models of the two activities were developed using stepwise regression and multilayer perceptron neural network based on the calculated descriptors of quantum chemistry.The results showed that the significant molecular descriptor related to the antioxidant activity of carotenoids was the HOMO-LUMO energy gap(EHL) and the molecular descriptor related to the GJC was the lowest unoccupied molecular orbital energy(ELUMO).The two models of antioxidant activity both showed good predictive power,but the predictive power of the neural network QSAR model of antioxidant activity was better.In addition,the two GJC models have similar,moderate predictive power.The possible mechanisms of antioxidant activity and GJC of carotenoids were discussed. 展开更多
关键词 carotenoids antioxidant activity gap junctional communication multilayer perceptron neural network quantitative structure-activity relationship
下载PDF
Quantitative structure-activity relationship study on the biodegradation of acid dyestuffs 被引量:9
17
作者 LI Yin XI Dan-li 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第7期800-804,共5页
Quantitative structure-biodegradability relationships (QSBRs) were established to develop predictive models and mechanistic explanations for acid dyestuffs as well as biological activities. With a total of four desc... Quantitative structure-biodegradability relationships (QSBRs) were established to develop predictive models and mechanistic explanations for acid dyestuffs as well as biological activities. With a total of four descriptors, molecular weight (MW), energies of the highest occupied molecular orbital (EHOMO), the lowest unoccupied molecular orbital (ELUMO), and the excited state (EES), calculated using quantum chemical semi-empirical methodology, a series of models were analyzed between the dye biodegradability and each descriptor. Results showed that EHOMO and Mw were the dominant parameters controlling the biodegradability of acid dyes. A statistically robust QSBR model was developed for all studied dyes, with the combined application of EHOMO and Mw. The calculated biodegradations fitted well with the experimental data monitored in a facultative-aerobic process, indicative of the reliable prediction and mechanistic character of the developed model. 展开更多
关键词 quantitative structure-activity relationship (QSAR) acid dyestuff BIODEGRADABILITY DECOLORIZATION
下载PDF
Proposal and evaluation of a new norm index-based QSAR model to predict pEC50 and pCC50 activities of HEPT derivatives 被引量:2
18
作者 Kanwal Shahid Qiang Wang +4 位作者 Qingzhu Jia Lei Li Xue Cui Shuqian Xia Peisheng Ma 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第10期1464-1469,共6页
The search and development of anti-HIV drugs is currently one of the most urgent tasks of pharmacological studies. In this work, a quantitative structure-activity relationship (QSAR) model based on some new norm ind... The search and development of anti-HIV drugs is currently one of the most urgent tasks of pharmacological studies. In this work, a quantitative structure-activity relationship (QSAR) model based on some new norm indexes, was obtained to a series of more than 150 HEPT derivatives (1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine) to find their pEC50 (the required effective concentration to achieve 50% protection of MT-4 cells against the cytopathic effect of virus) and pCC50 (the required cytotoxic concentration to reduce visibility of 50% mock infected cell) activities. The model efficiencies were then validated using the leave-one-out cross validation (LOO-CV) and y- randomization test. Results indicated that this new model was efficient and could provide satisfactory results for prediction of pECso and pCC50 with the higher R2 train and the higher Rt2est. By using the leverage approach, the applicability domain of this model was further investigated and no response outlier was detected for HEFT derivatives involved in this work. Comparison results with reference methods demonstrated that this new method could result in significant improvements for predicting pEC50 and pCC50 of anti-HIV HEPT derivatives. Moreover, results shown in this present study suggested that these two absolutely different activities pECso and pCC50 of anti-HIV HEPT derivatives could be predicted well with a totally similar QSAR model, which indicated that this model mizht have the potential to be further utilized for other biological activities of HEFT derivatives. 展开更多
关键词 Mathematical modeling Structure-activity relationship Pharmaceuticals HEFT derivatives Anti-HIV-1 activity Prediction
下载PDF
Application of PCA and HCA to the Structure-activity Relationship(SAR) Study of Fluoroquinolones 被引量:1
19
作者 LI Xiao-Hong ZHANG Rui-Zhou +1 位作者 CHENG Xin-Lu YANG Xiang-Dong 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第11期1351-1358,共8页
Density functional theory (DFT) was used to calculate a set of molecular descri ptors (properties) for 14 fluoroquinolones with anti-B.fragilis activity. Principal component analysis (PCA) and hierarchical clust... Density functional theory (DFT) was used to calculate a set of molecular descri ptors (properties) for 14 fluoroquinolones with anti-B.fragilis activity. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were employed in order to reduce dimensionality and investigate which subset of variables should be more effective for classifying fluoroquinolones according to their an-B.fragilis activity degree. The PCA shows that the variables of ELUMO, AEHL, μ, Q2, Q3, Q5, Q6, QB, LogP, MR and MP are responsible for the separation between compounds with higher and lower anti-B.fragilis activities. The HCA results are similar to those obtained with PCA. By using the chemometric results, 4 synthetic compounds were analyzed through PCA and HCA, and 2 of them are proposed as active molecules against B.fragilis, which is consistent with the results of clinic experiments. The methodologies of PCA and HCA provide a reliable rule for classifying new fluoroquinolones with anti-B.fragilis activity. 展开更多
关键词 structure-activity relationship DFT PCA HCA
下载PDF
Synthesis and Antitumor Activities of 26-O-tert-Butyldimethylsiliyl Protodisogenyl β-D-Glucopyranoside
20
作者 Liang ZHOU Shu Jie HOU Peng XU De Quan YU Ping Sheng LEI Chuan Chun ZOU 《Chinese Chemical Letters》 SCIE CAS CSCD 2006年第5期571-574,共4页
New saponin 26-O-tert-butyldimethylsiliyl protodiosgenyl β-D-glucopyranoside 1 was synthesized and its cytotoxicity activity in vitro was evaluated by MTI'. It showed potent antitumor activity to human cancer cells.... New saponin 26-O-tert-butyldimethylsiliyl protodiosgenyl β-D-glucopyranoside 1 was synthesized and its cytotoxicity activity in vitro was evaluated by MTI'. It showed potent antitumor activity to human cancer cells. E ring and C22-OH play important roles in the antitumor activity of 1. A method to selective removal of acetyl group in the presence of benzoyl group was reported. 展开更多
关键词 SAPONIN GLYCOSYLATION cytotoxicity activity structure-activity relationship.
下载PDF
上一页 1 2 177 下一页 到第
使用帮助 返回顶部