• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 111
  • 89
  • 12
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 269
  • 53
  • 48
  • 38
  • 37
  • 37
  • 35
  • 32
  • 26
  • 25
  • 25
  • 25
  • 24
  • 21
  • 20
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Entwicklung, Validierung und Anwendung einer interpretierbaren und alignment-freien 4D-QSAR-Methodik

Scheiber, Josef Heinrich. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2007--Würzburg. / Erscheinungsjahr an der Haupttitelstelle: 2006.
2

Desenvolvimento de softwares, algoritmos e diferentes abordagens quimiométricas em estudos de QSAR / Development of softwares, algorithms and different chemometric aproaches in QSAR studies

Martins, João Paulo Ataíde, 1980- 25 August 2018 (has links)
Orientador: Márcia Miguel Castro Ferreira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-25T11:39:21Z (GMT). No. of bitstreams: 1 Martins_JoaoPauloAtaide_D.pdf: 3637503 bytes, checksum: 5fe52d182b4f300eb103baf168ad75ab (MD5) Previous issue date: 2013 / Resumo: O planejamento de fármacos com o auxílio do computador é uma área de pesquisa de extrema importância em química e áreas correlatas. O conjunto de ferramentas disponíveis para tal fim consiste, dentre outras, em programas para geração de descritores e construção e validação de modelos matemáticos em QSAR (do inglês, Quantitative Structure-Activity Relationship). Com o objetivo de tornar esse estudo mais acessível para a comunidade científica, novas metodologias e programas para geração de descritores e construção e validação de modelos QSAR foram desenvolvidos nessa tese. Uma nova metodologia de QSAR 4D, conhecida com LQTA-QSAR, foi desenvolvida com o objetivo de gerar descritores espaciais levando em conta os perfis de amostragem conformacional das moléculas em estudo obtidos a partir de simulações de dinâmica molecular. A geração desses perfis é feita com o software livre GROMACS e os descritores são gerados a partir de um novo software desenvolvido nesse trabalho, chamado de LQTAgrid. Os resultados obtidos com essa metodologia foram validados comparando-os com resultados obtidos para conjuntos de dados disponíveis na literatura. Um outro software de fácil uso, e que engloba as principais ferramentas de construção e validação de modelos em QSAR, foi desenvolvido e chamado de QSAR modeling. Esse software implementa o método de seleção de variáveis OPS, desenvolvido em nosso laboratório, e utiliza PLS (do inglês Partial Least Squares) como método de regressão. A escolha do algoritmo PLS implementado no programa foi feita com base em um estudo sobre o desempenho e a precisão no erro de validação dos principais algoritmos PLS disponíveis na literatura. Além disso, o programa QSAR modeling foi utilizado em um estudo de QSAR 2D para um conjunto de 20 flavonóides com atividade anti-mutagênica contra 3-nitrofluoranteno (3-NFA) / Abstract: Computer aided drug design is an important research field in chemistry and related areas. The available tools used in such studies involve software to generate molecular descriptors and to build and validate mathematical models in QSAR (Quantitative Structure-Activity Relationship). A new set of methodologies and software to generate molecular descriptors and to build and validate QSAR models were developed aiming to make these kind of studies more accessible to scientific community. A new 4DQSAR methodology, known as LQTA-QSAR, was developed with the purpose to generate spatial descriptors taking into account conformational ensemble profile obtained from molecular dynamics simulations. The generation of these profiles is performed by free software GROMACS and the descriptors are generated by a new software developed in this work, called LQTAgrid. The results obtained with this methodology were validated comparing them with results available in literature. Another user friendly software, which contains some of the most important tools used to build and validate QSAR models was developed and called QSAR modeling. This software implements the OPS variable selection algorithm, developed in our laboratory, and uses PLS (Partial Least Squares) as regression method. The choice of PLS algorithm implemented in the program was performed by a study about the performance and validation precision error involving the most important PLS algorithms available in literature. Further, QSAR modeling was used in a 2D QSAR study with 20 flavonoid derivatives with antimutagenic activity against 3-nitrofluoranthene (3-NFA) / Doutorado / Físico-Química / Doutor em Ciências
3

Entwicklung, Validierung und Anwendung einer interpretierbaren und alignment-freien 4D-QSAR Methodik / Development, Validation and Application of an interpretable and alignment-free 4D-QSAR technique

Scheiber, Josef Heinrich January 2006 (has links) (PDF)
Die vorliegende Arbeit beschreibt die Entwicklung, Validierung und erfolgreiche Anwendung der interpretierbaren 4D-QSAR Methodik xMaP. Die neue Methode benötigt weder die Auswahl des vermuteten bioaktiven Konformers noch eine Überlagerung der Moleküle im Raum, sie ist also alignment-frei. xMaP ist invariant gegenüber Rotation, Translation und kodiert die Flexibilität der Moleküle. Dadurch wird der Einfluss durch den Benutzer praktisch ausgeschaltet. / This thesis describes the development, validation and successful application of the interpretable 4D-QSAR technique xMaP. The novel method does neither rely on the selection of a presumed bioactive conformer nor on a spatial superimposition of the molecules which means that it is so-called alignment-free. Put differently, xMaP is invariant to rotation and translation and encodes the flexibility of the molecules under scrutiny. By combining these features a possible user bias is almost completely eliminated.
4

Computergestützte Analyse von Piritrexim und Analoga: 3D-QSAR, Molecular Modeling und Strukturbasiertes Wirkstoffdesign /

Fleischer, Romy. January 1999 (has links) (PDF)
Univ., Diss.--Halle-Wittenberg, 1999.
5

Computeranwendungen in der Chemie Visualisierung chemischer Reaktionen und Generierung von QSAR-Modellen /

Brunberg, Ingo. January 2001 (has links) (PDF)
Paderborn, Univ., Diss., 2001. / Computerdatei im Fernzugriff.
6

Computeranwendungen in der Chemie Visualisierung chemischer Reaktionen und Generierung von QSAR-Modellen /

Brunberg, Ingo. January 2001 (has links) (PDF)
Paderborn, Univ., Diss., 2001. / Computerdatei im Fernzugriff.
7

QSPR modeling of some properties of organic compounds /

Tämm, Kaido, January 2006 (has links) (PDF)
Thesis (doctoral)--University of Tartu, 2006. / This dissertation is based on 4 papers. Includes bibliographical references.
8

Applications of quantum chemistry to polymerization reactions and biological activity

Miller, Matthew Dean, Holder, Andrew J. January 2004 (has links)
Thesis (Ph. D.)--Dept. of Chemistry and School of Pharmacy. University of Missouri--Kansas City, 2004. / "A dissertation in chemistry and pharmaceutical science." Advisor: Andrew J. Holder. Typescript. Vita. Description based on contents viewed Feb. 27, 2006; title from "catalog record" of the print edition. Includes bibliographical references (leaves 206-221). Online version of the print edition.
9

Computeranwendungen in der Chemie Visualisierung chemischer Reaktionen und Generierung von QSAR-Modellen /

Brunberg, Ingo. January 2001 (has links) (PDF)
Paderborn, Universiẗat, Diss., 2001.
10

Estudos computacionais da enzima N-miristoiltransferase de Plasmodium falciparum e seus inibidores como candidatos a agentes antimaláricos / Computational studies on Plasmodium falciparum N-myristoyltransferase enzyme and its inhibitors as antimalarial drug candidates

Garcia, Mariana Lopes 18 July 2017 (has links)
A malária é uma doença infecciosa causada pelos parasitas do gênero Plasmodium e transmitida pelo mosquito Anopheles spp. Devido ao surgimento de casos de resistência aos fármacos disponíveis novos alvos e candidatos a fármacos são necessários. Recentemente, a enzima N-miristoiltransferase (NMT) foi confirmada como essencial para o parasita e validada como alvo terapêutico para o desenvolvimento de candidatos a fármacos antimaláricos. O objetivo desse trabalho foi identificar os determinantes moleculares responsáveis pela atividade inibitória de uma série de derivados benzotiofênicos frente à NMT. Nesse sentido, estudos de relação quantitativa estrutura-atividade (QSAR) 2D e 3D foram desenvolvidos para dois conjuntos de dados de derivados benzotiofênicos como inibidores da enzima do parasita (PfNMT) e a homóloga humana (HsNMT). Além disso, estudos de modelagem por homologia da PfNMT foram conduzidos. Os estudos de QSAR 2D foram desenvolvidos pelo método de Holograma QSAR (HQSAR). O modelo estrutural de PfNMT foi aplicado na construção dos modelos QSAR 3D CoMFA (Comparative Molecular Field Analysis) e CoMSIA (Comparative Molecular Similarity Index Analysis). Os estudos de QSAR 3D foram conduzidos com diferentes métodos de cálculo de carga parcial atômica (Gasteiger-Hückel, MMFF94 e AM1-BCC, CHELPG e Mulliken) e de alinhamento molecular (Máxima Subestrutura Comum, alinhamento flexível e baseada no alvo molecular). Os melhores modelos construídos pelos métodos de QSAR 2D e 3D foram robustos, internamente consistentes e com elevada capacidade de predição da atividade de novos compostos contra a PfNMT. Os mapas de contribuição e de contorno geraram informações importantes sobre a relação estrutura-atividade dos compostos. Os resultados permitiram a identificação das bases moleculares responsáveis pela atividade dos inibidores benzotiofênicos e são úteis para o planejamento de novos inibidores mais potentes e seletivos para a enzima do parasita. / Malaria is an infectious disease caused by protozoan parasites of the genus Plasmodium and transmitted by Anopheles spp. mosquitos. Due to the emerging resistance to current available drugs, great efforts for new molecular target and drugs are required. Recently, N-myristoyltransferase (NMT) was confirmed as an essential enzyme to malaria parasites and validated as a chemically tractable target for the development of new drug candidates against malaria. This work aimed to shed light on the molecular requirements underlying the inhibitory activity of benzothiophene derivatives against NMT. Therefore, 2D and 3D quantitative structure-activity relationship (QSAR) studies were developed for two datasets of benzothiophene derivatives as P. falciparum NMT (PfNMT) and the human homologue (HsNMT) inhibitors. Also, homology modeling studies for PfNMT were developed. The 2D QSAR studies were developed by the Hologram QSAR (HQSAR) method. The PfNMT structural model was applied in the construction of 3D QSAR models CoMFA (Comparative Molecular Field Analysis) and CoMSIA (Comparative Molecular Similarity Index Analysis). Different molecular alignment (maximum common substructure, flexible alignment and structure based) and atomic partial charge calculation (Gasteiger-Hückel, MMFF94, AM1-BCC, CHELPG and Mulliken) methods were used to build the 3D QSAR models. The best models showed internal consistency and high predictive ability of biological activity against PfNMT. The contribution and contour maps gave important information about compounds structure-activity relationship. The results allowed the identification of the molecular requirements underlying the inhibitory activity and should be useful for the design of novel potent and selective PfNMT inhibitors as antimalarial drug candidates.

Page generated in 0.0337 seconds