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  • 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.
311

On the Structure Differences of Short Fragments and Amino Acids in Proteins with and without Disulfide Bonds

Dayalan, Saravanan, saravanan.dayalan@rmit.edu.au January 2008 (has links)
Of the 20 standard amino acids, cysteines are the only amino acids that have a reactive sulphur atom, thus enabling two cysteines to form strong covalent bonds known as disulfide bonds. Even though almost all proteins have cysteines, not all of them have disulfide bonds. Disulfide bonds provide structural stability to proteins and hence are an important constraint in determining the structure of a protein. As a result, disulfide bonds are used to study various protein properties, one of them being protein folding. Protein structure prediction is the problem of predicting the three-dimensional structure of a protein from its one-dimensional amino acid sequence. Ab initio methods are a group of methods that attempt to solve this problem from first principles, using only basic physico-chemical properties of proteins. These methods use structure libraries of short amino acid fragments in the process of predicting the structure of a protein. The protein structures from which these structure libraries are created are not classified in any other way apart from being non-redundant. In this thesis, we investigate the structural dissimilarities of short amino acid fragments when occurring in proteins with disulfide bonds and when occurring in those proteins without disulfide bonds. We are interested in this because, as mentioned earlier, the protein structures from which the structure libraries of ab initio methods are created, are not classified in any form. This means that any significant structural difference in amino acids and short fragments when occurring in proteins with and without disulfide bonds would remain unnoticed as these structure libraries have both fragments from proteins with disulfide bonds and without disulfide bonds together. Our investigation of structural dissimilarities of amino acids and short fragments is done in four phases. In phase one, by statistically analysing the phi and psi backbone dihedral angle distributions we show that these fragments have significantly different structures in terms of dihedral angles when occurring in proteins with and without disulfide bonds. In phase two, using directional statistics we investigate how structurally different are the 20 different amino acids and the short fragments when occurring in proteins with and without disulfide bonds. In phase three of our work, we investigate the differences in secondary structure preference of the 20 amino acids in proteins with and without disulfide bonds. In phase four, we further investigate and show that there are significant differences within the same secondary structure region of amino acids when they occur in proteins with and without disulfide bonds. Finally, we present the design and implementation details of a dihedral angle and secondary structure database of short amino acid fragments (DASSD) that is publicly available. Thus, in this thesis we show previously unknown significant structure differences in terms of backbone dihedral angles and secondary structures in amino acids and short fragments when they occur in proteins with and without disulfide bonds.
312

Structure-property relationships in solid state materials a computational approach emphasizing chemical bonding /

Stoltzfus, Matthew W., January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 189-196).
313

Synderskan och lagen: Barnamord i tre Norrlandslän 1830-1870

Johansson, Gun-Britt January 2006 (has links)
<p>ABSTRACT</p><p>Many studies have been conducted on infanticide and child homicide. Researchers have approached the subject with different theoretical frameworks and explored it from different dimensions, geographical areas, and time periods. As much as the questions have varied so have the answers. This study contributes to greater clarity on the causes of infanticide. Despite numerous studies on the subject, there is still no consensus its causes. My aim has been to combine different strategies for understanding the subject. I have used material both from an aggregated level and from an individual level. The main question I sought to answer was whether social causes rather than individual factors force or trigger women to kill their newborn child? Court material also provides for an in-depth understanding of our history. The social sciences have frequently drawn sketches of the social world with big lines. These lines have been necessary and useful to point at large-scale transformations of civilisation and modernisation but, in terms of understanding real life, they can provide us with a foggy and even mistaken picture. When social scientists enter the historical archives and similar sources, we often blunder in its richness and variation. Society may, in any case, have always been complicated and the every day life for each person as well.</p><p>My findings show that infanticide signals low tolerance. In general, the women did not want to kill their own children. Moreover, my findings, like the results of other studies before mine, demonstrate that women who carry out infanticide represent normal women. To my knowledge, there isn’t one study on infanticide that claims the women were not normal. Women who committed infanticide did so out of fear: fear of losing their social bonds. They killed their children if the existence of the bonds was endangered or threatened. Often social bonds were related to their work situation as maids in farming households. If they couldn’t stay in the household after having the baby, many women had no where else to go. Their parents – poor, elderly or deceased – were unable to help. Sometimes the social bonds were threatened by other factors, often related to the child’s father. If he was already married or had a close relation with the woman’s family, their relationship could in fact, break her bonds to her own family and other relatives. Some women already had an illegitimate child. With a child out of wedlock, they had a difficult time getting work and housing. If they got pregnant again and the father to the new child refused to marry her or to support the child, she could in fact lack any resources for handling the situation.</p><p>Finally: the findings talk about honour and infanticide. It was always shameful to get a child out of wedlock. But demographic research from North of Sweden has shown that these children had almost the same chances of survival during their first year as legitimate children. Sexuality outside marriage was not respected but much discussion around honour was more related to how the women would manage with the child. In my findings, shame seems to be related to having no support. Extramarital relations were not accepted but people probably didn’t care to much about it as far as they managed on their own. Being rejected, helpless, not able to work and not able to take care of the child that was what shame was about.</p><p>Keywords: Infanticide, child homicide, illegitimacy, social bonds, shame</p>
314

Synderskan och lagen: Barnamord i tre Norrlandslän 1830-1870

Johansson, Gun-Britt January 2006 (has links)
ABSTRACT Many studies have been conducted on infanticide and child homicide. Researchers have approached the subject with different theoretical frameworks and explored it from different dimensions, geographical areas, and time periods. As much as the questions have varied so have the answers. This study contributes to greater clarity on the causes of infanticide. Despite numerous studies on the subject, there is still no consensus its causes. My aim has been to combine different strategies for understanding the subject. I have used material both from an aggregated level and from an individual level. The main question I sought to answer was whether social causes rather than individual factors force or trigger women to kill their newborn child? Court material also provides for an in-depth understanding of our history. The social sciences have frequently drawn sketches of the social world with big lines. These lines have been necessary and useful to point at large-scale transformations of civilisation and modernisation but, in terms of understanding real life, they can provide us with a foggy and even mistaken picture. When social scientists enter the historical archives and similar sources, we often blunder in its richness and variation. Society may, in any case, have always been complicated and the every day life for each person as well. My findings show that infanticide signals low tolerance. In general, the women did not want to kill their own children. Moreover, my findings, like the results of other studies before mine, demonstrate that women who carry out infanticide represent normal women. To my knowledge, there isn’t one study on infanticide that claims the women were not normal. Women who committed infanticide did so out of fear: fear of losing their social bonds. They killed their children if the existence of the bonds was endangered or threatened. Often social bonds were related to their work situation as maids in farming households. If they couldn’t stay in the household after having the baby, many women had no where else to go. Their parents – poor, elderly or deceased – were unable to help. Sometimes the social bonds were threatened by other factors, often related to the child’s father. If he was already married or had a close relation with the woman’s family, their relationship could in fact, break her bonds to her own family and other relatives. Some women already had an illegitimate child. With a child out of wedlock, they had a difficult time getting work and housing. If they got pregnant again and the father to the new child refused to marry her or to support the child, she could in fact lack any resources for handling the situation. Finally: the findings talk about honour and infanticide. It was always shameful to get a child out of wedlock. But demographic research from North of Sweden has shown that these children had almost the same chances of survival during their first year as legitimate children. Sexuality outside marriage was not respected but much discussion around honour was more related to how the women would manage with the child. In my findings, shame seems to be related to having no support. Extramarital relations were not accepted but people probably didn’t care to much about it as far as they managed on their own. Being rejected, helpless, not able to work and not able to take care of the child that was what shame was about. Keywords: Infanticide, child homicide, illegitimacy, social bonds, shame
315

Controlled, Encouraged or Adrift? Sources of Variation in Adolescent Substance Use

Fidler, Tara Leah 11 December 2012 (has links)
The frequent consumption of alcohol and cannabis by youth poses both concern and ambivalence to society about the nature of the problem and how to respond. In the last few decades, social science research has devoted considerable attention to substance use among youth, making it an important issue to consider; however, controversy abounds when considering where consumption patterns of youth fall on a continuum from normal to deviant. Central to these debates is the social acceptability of the substances being used, their legal status, the frequency with which they are consumed, and the particular groups most often engaged in their use. Youth who consume alcohol are viewed with less trepidation than those who consume cannabis. Moreover, those who use either substance recreationally or experimentally are deemed to be more typical than those who have escalated their use to more regular or frequent episodes. Finally, drug-using youth who are embedded in conventional society are viewed more positively than those who occupy the margins of society, such as those who are delinquent or homeless. To fully understand the debate about the deviancy versus the normalcy of adolescent substance use, more inclusive approaches that take into account structural, individual and situational explanations are needed; however, existing studies fail to consider all of these influences. Instead, there is debate about the dominance of each of these explanations. This dissertation examines and tests these competing representations and explanations of adolescent substance use by drawing on multiple sociological theories of deviance including control theories, differential association theory, routine activity approaches, and drift theory. Using a combined sample of high school students and street youth, the findings suggest that adolescent substance use is far too complex to be explained by only one theory. Instead, explanations for the variations in substance use must take into account both individual backgrounds and more immediate situational influences. Most importantly, individual beliefs about substances are an important and often ignored aspect of individual substance use patterns.
316

A study of Germanium phthalocyanines

Mahabbis, Mohamed T. 03 June 2011 (has links)
This thesis has involved an attempt to form a germanium-carbon bond through the reaction of germanium compounds with dilithium phthalocyanine, metal-free phthalocyanine, methyl magnesium iodide, phenyl magnesium bromide, and 1,3-diiminoisoindoline. The reaction products were examined in several ways to help establish their identity. Chemical and spectroscopic analyses were used to determine the nature of the two trans groups in the phthalocyanine compounds. Infrared spectra implied the formation of the germanium-carbon bond.Ball State UniversityMuncie, IN 47306
317

Studies of Capacity Losses in Cycles and Storages for a Li1.1Mn1.9 O 4 Positive Electrode

Nishibori, Eiji, Takata, Masaki, Sakata, Makoto, Fujita, Miho, Sano, Mitsuru, Saitoh, Motoharu January 2004 (has links)
No description available.
318

The bond structure in the alkaline-ferric-tartrate system

Hanby, John E. 01 January 1968 (has links)
No description available.
319

The formation and structural investigation of galacturonides from a galactoglucomannan and a galactomannan.

Rogers, John K. 01 January 1968 (has links)
No description available.
320

The autoxidation of methyl glycopyranosides

Church, John A. 01 January 1964 (has links)
No description available.

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