HEPT类HIV-1逆转录酶衍生物的CoMFA、CoMSIA及HQSAR分析

采用比较分子力场分析法(CoMFA)、比较分子相似因子分析法(CoMSIA)和分子全息定量结构关系(HQSAR)对1-[(2-羟乙氧)甲基]-6-苯硫基胸腺嘧啶(HEPT)类衍生物进行了分子活性构象选择、分子叠合、空间力场范围建立以及相应3D-QSAR模型建立。结果表明:该法所建模型对此类化合物具有良好的预测能力。CoMFA模型显示,交叉验证系数(q2)为0.565,非交互验证系数(r2)为0.892;CoMSIA模型显示,最佳q2为0.636,r2为0.953;最佳的HQSAR模型显示,q2为0.876,r2为0.929,最佳全息长度为97。根据三维等势图和HQSAR色码图设计了7个有较高活性的HEPT类化合物。     

G蛋白偶联受体109B苯甲酸类激动剂三维定量构效关系

5-N,N-二取代5-氨基吡唑-3-羧酸、3-硝基-4-氨基苯甲酸和6-氨基烟酸类化合物是G蛋白偶联受体109B(GPR109B)潜在生物活性药物。本实验采用比较分子力场分析法(Co MFA)和比较分子相似性指数分析法(Co MSIA)分别建立46个GPR109B激动剂分子的3D-QSAR模型,确定此类G蛋白偶联受体激动剂的分子结构与生物活性之间的定量关系。Co MFA模型的训练集抽一法交叉验证系数q~2=0.472,非交叉验证系数r~2=0.92,标准偏差SE=0.212;CoMSIA模型的训练集抽一法交叉验证系数q~2=0.498,非交叉验证系数r~2=0.803,标准偏差SE=0.332。两个3D-QSAR模型预测数值与实验数据基本一致,显示模型具有较好的预测能力。本实验根据CoMFA和CoMSIA模型所提供的立体场、静电场、氢键给体场等信息进一步提出改善此类激动剂生物活性的药物设计思路。     

聚氧乙烯类和硫酸盐类表面活性剂HLB值的研究

亲水亲油平衡值(Hydrophile/Lipophile Balance,HLB)是表征表面活性剂性质的重要参数。采用比较分子力场分析(comparative molecular field analysis,CoMFA)方法和比较分子相似性指数分析(comparative similarity indices analysis,CoMSIA)方法,研究了30个烷基酚聚氧乙烯醚系列非离子表面活性剂的三维定量结构与pHLB值的关系。建立的CoMFA模型交叉验证系数为0.705,非交叉验证系数为0.805:CoMSIA模型交叉验证系数为0.685,非交叉验证系数为0.813,都有较好的预侧能力。此外,运用多元线性回归方法建立一种预报硫酸盐类表面活性剂HLB的QSPR模型,模型的复相关系数为0.711。所有选取的测试集和训练集的预报结果较为吻合,说明硫酸盐类表面活性剂HLB值QSPR模型具有良好的预报能力和普适性。     

硅烷偶联剂折光率的全息定量构效关系研究

建立了85个硅烷偶联剂折光率的全息定量构效关系(HQSAR)模型。当设置参数fragment distinction为“A、B、C、H、DA”、fragment size为“4～7”、holograms length为“151”时可建立最优HQSAR模型。采用外部测试集验证和留一交叉验证两种方法评估了模型的预测能力和稳健性。外部测试集验证的RMSRE、RMSEP、Q²_F3、CCC分别为0.916、0.013、0.924、0.936，留一交叉验证的RMSRE、RMSECV、q²_cv和R²分别为1.364、0.020、0.659和0.829。验证结果表明建立的HQSAR模型稳健可靠，可用于预测硅烷偶联剂的折光率。此外，通过所得HQSAR模型的分子贡献图可知，硅烷偶联剂中苯基和氧原子上长链烷基的存在会提高折光率。     

靛玉红类衍生物的三维定量构效关系研究

采用比较分子场方法(CoMFA)对16个靛玉红类衍生物进行三维定量构效关系(3D-QSAR)研究,探讨靛玉红类衍生物的抗癌活性与其结构的关系。建立了3D-QSAR的CoMFA模型,得到了非交叉验证相关系数r2=0.987,标准偏差SD=2.141,统计方差比F=117.136,交叉验证相关系数q2=0.496。该模型合理、可信,具有一定的预测能力,表明改变取代基R1基团的体积才是提高靛玉红类衍生物抗癌活性的主要途径,为开发活性更好的抗癌药物提供一定的理论参考。     

HQSAR模型预测染料敏化太阳能电池香豆素衍生物PCE值研究

采用全息定量构效关系(HQSAR)方法建立了染料敏化太阳能电池香豆素类染料敏化剂结构信息与光电转化效率(PCE)之间的定量结构性质关系(QSPR)模型。构建的最有效HQSAR模型(q_cv²=0.895,R²=0.946)的片段参数为：fragment size “2～7”:hologram length “97”,fragment distinctions“B”。两种验证方法,外部测试集验证和留一法交叉验证(LOO-CV)用于检验开发的最佳HQSAR模型的质量。结果表明,HQSAR方法可以作为一种快速有效的工具,来预测香豆素染料敏化太阳能电池的PCE值。     

唑类化合物密度的全息定量构效关系模型研究

唑类化合物是一种爆轰性能与密度相关的重要的能量材料, 建立了唑类化合物的密度的全息定量构效关系 (HQSAR) 模型。 模型参数选择为fragment size： “1 ～ 2”,fragment distinction： “A、 B、 H、 DA” 可建立最佳 HQSAR 模型。 采用两种常规验证技术, 即外部测试集验证和留一交叉验证 (LOO - CV) 来评估 HQSAR 模型的预测精度。 采用外部测试集验证和留一交叉验证两种方法对所建立模型进行了验证, 外部测试集验证中的RMSRE、RMSEP、MRE、Q²_F3、 ■和 Δr_m²分别为 0. 020、 0. 044、 2. 04% 、 0. 891、 0. 670、 0. 220。 留一交叉验证中的 RMSRE、RMSECV、MRE、 r_m²和 Δr_m²分别为 0. 043、 0. 070、 3. 20% 、 0. 602 和 0. ...     

基于Topomer CoMFA法的类黄酮类化合物乙酰胆碱酯酶抑制剂的三维定量构效关系研究

建立类黄酮类乙酰胆碱酯酶抑制剂的三维定量构效关系(3D-QSAR)模型。采用Topomer CoMFA法研究类黄酮类乙酰胆碱酯酶抑制剂的构效关系。建立了可靠、合理的类黄酮类乙酰胆碱酯酶抑制剂Topomer CoMFA模型(q~2=0.812,r~2=0.921,r■=0.531)。建立的Topomer CoMFA模型揭示了类黄酮类化合物分子与其体外乙酰胆碱酯酶抑制活性间的关系,可以有助于合理设计具有更好活性的乙酰胆碱酯酶抑制剂。     

芳胺类染料敏化太阳能电池能量转化效率的HQSAR研究

基于HQSAR方法,建立了35种芳胺类化合物分子结构与相应能量转化效率的定量构效关系模型。当碎片大小、碎片区分参数、全息长度和主成分数分别为“B、H、Ch、DA”、“4-7”、“97”和“6”时,可以建立最优HQSAR模型。采用两种验证方法对模型的稳健性和预测能力进行了评价,留一交叉验证中q²=0.734,r²=0.940;外部测试集验证中■。结果表明,所建立的模型具有良好的稳健性和预测能力,可以对芳胺类化合物的能量转化效率进行比较准确的预测。     

咪唑[1,2-b]哒嗪类mTOR抑制剂的三维定量构效关系及分子对接研究

目的:建立咪唑[1,2-b]哒嗪类m TOR抑制剂的三维定量构效关系(3D-QSAR)和分子对接模型。结合两个模型实验结果,分析化合物的结构与其生物活性间关系。方法 采用比较分子分析法(Co MFA)和比较分子相似性指数分析法(Co MSIA)来研究咪唑[1,2-b]哒嗪类m TOR抑制剂的三维定量构效关系,用分子对接方法来研究化合物与受体蛋白之间的相互作用模式。结果:建立了可靠、合理的咪唑[1,2-b]哒嗪类m TOR抑制剂Co MFA(q2=0.628,r2=0.989,r2pred=0.991)和Co MSIA(q2=0.593,r2=0.988,r2pred=0.989)模型。通过分析分子对接模型得出化合物与受体蛋白之间有关键的氢键连接。设计出了新化合物并预测了活性。结论:根据3DQSAR模型得到咪唑[1,2-b]哒嗪类m TOR抑制剂的结构与生物活性之间的关系,分析分子对接模型发现化合物与受体蛋白之间的作用关系,基于以上设计出了具有较好活性的新化合物。实验的研究发现为该类m TOR抑制剂的设计优化提供了思路。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。