{"title":"Design Optimization of Photoelectrode Reactor for Hydrogen Production by Combining CFD Simulation and Statistical Methods","authors":"Y. Maeda, K. Funatsu","doi":"10.2751/JCAC.12.1","DOIUrl":"https://doi.org/10.2751/JCAC.12.1","url":null,"abstract":"","PeriodicalId":41457,"journal":{"name":"Journal of Computer Aided Chemistry","volume":"12 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69254800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Advanced PLS Technique Focusing on Visualization and Chemical Interpretation - SOMPLS Analysis of Serine Protease Inhibitors -","authors":"K. Hasegawa, K. Funatsu","doi":"10.2751/JCAC.11.56","DOIUrl":"https://doi.org/10.2751/JCAC.11.56","url":null,"abstract":"In quantitative structure activity relationships (QSAR), partial least squares (PLS) are of particular interest as a statistical method. Since successful applications of PLS to QSAR data set, PLS has evolved for coping with more demands associated with complex data structures. Especially, PLS variants focusing on visualization and chemical interpretation are highly desirable for molecular design. In this paper, we employed the self-organized map PLS (SOMPLS) approach to predict multiple inhibitory activities against three serine protease receptors (Factor Xa, Tryptase and urokinase-type Plasminogen Activator (uPA)). Retrosynthetic Combinatorial Analysis Procedure (RECAP) fingerprints were used as chemical descriptors that express the existence of specific substructure in the molecule. From the SOMPLS analysis and the subsequent correlation map, essential fragments for each serine protease were easily identified. From the correlation map, we designed best combinations of fragments at each substituent position for each serine protease protein. The essential fragments could be validated from X-ray crystal structures of serine protease receptors in computer graphics. SOMPLS is an unique approach that makes data-mining feasible from visualization of structure-activity data biased to ligand-based view point.","PeriodicalId":41457,"journal":{"name":"Journal of Computer Aided Chemistry","volume":"11 1","pages":"56-61"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69254742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ab initio MO Study of Hydrogen Bonding and Spectral Characteristics of HCN-H2O-HCN Trimer: Comparison between Dimer and Trimer","authors":"Tomoya Takada, Shugo Ohshita","doi":"10.2751/jcac.11.36","DOIUrl":"https://doi.org/10.2751/jcac.11.36","url":null,"abstract":"Hydrogen bonding of HCN-H2O-HCN trimer has been studied by means of ab initio molecular orbital (MO) calculations. The changes in intermolecular interaction energy and vibrational frequency induced by addition of HCN molecule to HCN-H2O or H2O-HCN dimer are especially focused. The distances of hydrogen bonds in the trimer are calculated to be shorter than those in the corresponding dimers. The hydrogen bond distances are hence shortened by addition of another HCN. The interaction energies of the hydrogen bonds are also increased by addition of HCN. The dipole moment of the trimer is smaller than the sum of the dipole moments of the separate moieties (HCN + H2O + HCN). This is opposite of the previous result for H2O-HCN-H2O. The spectral shift of the stretching modes induced by hydrogen bond formation has been predicted by vibrational frequency analysis. The vibrational frequency of the asymmetric stretching mode of HCN included in the H2O-HCN part of the trimer is remarkably red-shifted from that of the H2O-HCN dimer. This information is expected to be useful for experimental detection of the trimer.","PeriodicalId":41457,"journal":{"name":"Journal of Computer Aided Chemistry","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69254724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kazuaki Yoshimura, R. Ishikawa, H. Miyazaki, Atsushi Kawata, Michinori Sumimoto, K. Hori
{"title":"A Theoretical Study on the Temperature Control of Fabrication of Pentacene Thin Film Transistors from Soluble Pentacene Precursors","authors":"Kazuaki Yoshimura, R. Ishikawa, H. Miyazaki, Atsushi Kawata, Michinori Sumimoto, K. Hori","doi":"10.2751/JCAC.11.62","DOIUrl":"https://doi.org/10.2751/JCAC.11.62","url":null,"abstract":"ペンタセンを用いた塗布型有機半導体素子の作成法として、可溶性のペンタセン前駆体を塗布し逆Diels-Alder反応によりペンタセン骨格から脱離基を脱離させペンタセン薄膜へ転換する方法が提案されている。脱離基を変えた多くの前駆体に対して実験が行われ、それぞれペンタセンへの転換温度が異なることが示された。この転換温度と脱離基構造の関係を明らかにするため、報告されている6つの前駆体からペンタセンが生成する反応の解析を行った。その結果、活性化エネルギーEaが低い前駆体ほど転換温度が低い傾向にあることが明らかとなった。また重回帰解析を用いた検討により脱離基の最低非占有軌道(LUMO)と反応熱ΔEが低いほどEaが低いと計算された。次に、塗布成膜時に残存した溶媒の影響を調べるため、水素結合が形成される位置にメタノール分子を配置して、反応解析を行ったところ、Eaが気相中と比べわずかではあるが(最大で0.7 kcal mol-1)低下することが判明した。これは、前駆体の脱離基設計に加え展開溶媒として用いた分子の寄与を考慮することで、より転換温度の低い成膜プロセスが提案できる可能性を示している。","PeriodicalId":41457,"journal":{"name":"Journal of Computer Aided Chemistry","volume":"11 1","pages":"62-69"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2751/JCAC.11.62","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69254787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bayesian Classification of Cytochrome P450 3A4 Substrates/Non-substrates and Color Mapping for Chemical Interpretation","authors":"Kiyoshi Hasegawaa, Kimito Funatsub","doi":"10.2751/jcac.11.19","DOIUrl":"https://doi.org/10.2751/jcac.11.19","url":null,"abstract":"Prediction of cytochrome P450 (CYP) 3A4 substrates is valuable for finding promising drug candidates and a considerable amount of attention has been devoted to in silico predictions. Machine learning (ML) methods have recently been explored for perfoming ligand-based approaches. ML methods utilize supervised learning methods such as neural networks, support vector machines and Bayesian approaches to develop statistical models. In this paper, we used Bayesian approach to classify CYP 3A4 substrates and non-substrates. The extended connectivity fingerprint (ECFP) descriptor was used as chemical descriptor. The atom score was calculated from the Bayesian score of each fingerprint. By visualizing the atom scores with five graded-colors, the color mapping for each compound was performed. This can be used for chemical interpretaion why the specific compound exhibits CYP 3A4 substrate. The established Bayesian model and the associated color mapping would be useful for avoiding the risk of CYP 3A4 substrate in early drug discovery. The parallel use of the prediction of oxidation sites in the subsequent paper can give us de novo prediction of any molecules concerning CYP 3A4.","PeriodicalId":41457,"journal":{"name":"Journal of Computer Aided Chemistry","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2751/jcac.11.19","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69254332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of a Pharmacophore Modeling Method and its Application to Phosphodiesterase-4 Inhibitors","authors":"Masamoto Arakawa, M. Shoda, K. Funatsu","doi":"10.2751/JCAC.11.44","DOIUrl":"https://doi.org/10.2751/JCAC.11.44","url":null,"abstract":"新規医薬品の開発には多くの費用と時間を要するため、その効率化が強く望まれており、そのための有力な方法のひとつが、コンピュータと情報化学を利用して医薬品開発を行うインシリコ創薬である。特に、創薬プロセスの初期段階であるリード探索は、創薬プロセス全体の効率に大きな影響を与えるため、バーチャルスクリーニングによって質の高いリード化合物候補を発見する試みが数多く行われている。バーチャルスクリーニングを行うためのひとつの方法は、既知のリガンドからファーマコフォアモデルを構築し、それをもとにバーチャルライブラリの探索を行うことである。タンパクの立体構造を必要とせず、リガンドのみの情報で解析が可能であるという利点を持っている。ファーマコフォアモデルに基づくバーチャルスクリーニングにおいては、いかにして妥当なファーマコフォアを設定するかが重要であり、これまで様々な手法が提案されているが、決定的な手法は確立されていないのが現状である。そこで我々は、Hopfieldニューラルネットワークを利用して分子構造の重ね合わせを行うことによってファーマコフォアモデルを構築する手法を提案した。そして、その有用性を検証するため、Phosphodiesterase-4(PDE4)の阻害剤についてファーマコフォアモデルの構築を行った。活性を持つことがすでに知られている6つの阻害剤について配座探索を行い、得られた複数の配座のすべての組み合わせについて構造の重ね合わせを行った。そして、その重なりの度合いを指標として活性配座の推定を行い、ファーマコフォアを決定した。得られたファーマコフォアについて、PDE4のX線結晶構造を用いた検証を行った結果、活性部位の構造特徴を的確にとらえた妥当なモデルであることが確認された。","PeriodicalId":41457,"journal":{"name":"Journal of Computer Aided Chemistry","volume":"11 1","pages":"44-55"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69254735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Excitation Energies of Stacked DNA Base Pair","authors":"Muneaki Kamiya","doi":"10.2751/JCAC.11.25","DOIUrl":"https://doi.org/10.2751/JCAC.11.25","url":null,"abstract":"The excitation energies of uracil dimers have been calculated with the configuration interaction singles (CIS) method, the configuration interaction with single excitations with perturbed doubles (CIS(D)) method, the equation-of-motion coupled-cluster method with singles and doubles excitations (EOM-CCSD), and the time-dependent density-functional theory (TDDFT) with pure and hybrid functionals. It is shown that the charge transfer excitations behave as 1/R at large molecular distance limit and the local excited states are split by the so-called electronic couplings. The calculated excited energies by the ab initio methods (CIS, CIS(D), EOM-CCSD) well reproduce those features. But the results of TDDFT cannot show those features because of the short-sightness of exchange correlation functionals of DFT. The inclusion of the electron correlation is crucial to the excitation energies, especially to the charge transfer excitation, of which the excitation energies are decreased by more than 2 eV.","PeriodicalId":41457,"journal":{"name":"Journal of Computer Aided Chemistry","volume":"11 1","pages":"25-35"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69254711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ecotoxicity Prediction Using 3D Descriptors","authors":"日高 伸之介, 白石 寛明, 大眉 佳大, 山崎 広之, 岡本 晃典, 川下 理日人, 安永 照雄, 高木 達也","doi":"10.2751/JCAC.11.11","DOIUrl":"https://doi.org/10.2751/JCAC.11.11","url":null,"abstract":"A vast quantity of chemicals are present in our environment and are considered indispensable to our high technological society. However, there are some chemicals that are hazardous and that can extensively impact both human health and the global environment. In Japan, ecotoxicity tests of chemical substances have been conducted with the goal of contributing to the Organization for Economic Cooperation and Development (OECD) evaluation program for harmful high-production volume (HPV) chemicals since 1995. To date, only about 500 compounds have been tested. There is a possibility that quantitative structure-activity relationships (QSARs) may enable us to predict environmental toxicities and fates as well as the physical and chemical properties of compounds; therefore, the toxicity prediction by QSARs is a possible alternative to the measurements of their ecotoxicities. In this study, we generated QSAR models from toxicity tests of Daphnids using only 3D descriptors to examine the availability of particular 3D descriptors for predicting of the ecotoxicity of compounds with various structures. Predicton accuracy of the model generated in this study was adequate and improved compared to that of the model using only the n-octanol/water partition coefficient, logP(o/w).","PeriodicalId":41457,"journal":{"name":"Journal of Computer Aided Chemistry","volume":"40 1","pages":"11-18"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2751/JCAC.11.11","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69254266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Tanaka, T. Kawai, T. Takabatake, Hideho Okamoto, M. Bersohn
{"title":"Selective Search Focusing on Retro-Synthetically Important Bonds in A Synthesis Design System","authors":"A. Tanaka, T. Kawai, T. Takabatake, Hideho Okamoto, M. Bersohn","doi":"10.2751/JCAC.10.104","DOIUrl":"https://doi.org/10.2751/JCAC.10.104","url":null,"abstract":"A new capability has been added to the synthesis design system SYNSUP [1]. The new module generates synthetic routes that focus on key-bonds. Key-bonds are selected according to their spatial relationships to chiral atoms and central atoms of functional groups. When the key-bonds cannot be formed by any reaction known to SYNSUP, then structure changes in the vicinity of the bonds are effected so that the key-bonds can be disconnected in a retro-synthetic pathway. We called the fashion “selective search”. Such structure changes were studied, using 27 reported total synthesis of 25 naturally occurring compounds. This kind of selective search has been shown to be useful and practical for relatively complicated molecules.","PeriodicalId":41457,"journal":{"name":"Journal of Computer Aided Chemistry","volume":"10 1","pages":"104-117"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2751/JCAC.10.104","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69254543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}