• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 255
  • 2
  • Tagged with
  • 257
  • 257
  • 247
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

THE EFFECT OF ANALYTIC THINKING ON DELINQUENCY-RELATED FACTORS AND TREATMENT ENGAGEMENT AMONG ADOLESCENTS

Crawley, Rachel 19 December 2013 (has links)
This study aimed to propose and test an integrated model of information processing and dual-processing components (IP-DP model) to explain connections among delinquency-related factors and treatment engagement. Hypotheses stated that exposure to aggressive friends would be associated with maladaptive cognitive scripts, and maladaptive scripts would mediate relationships between exposure and delinquency, and exposure and engagement. Analytic thinking was expected to moderate these relationships by attenuating the negative effects of exposure and maladaptive scripts on outcome measures. Data were collected from 424 adolescents in 8 community-based residential treatment facilities as a part of the TCU Adolescent Project. Hypotheses were tested using PROC MIANALYZE to conduct multiple regression across 5 imputed datasets. Results indicated that maladaptive scripts partially mediate the relationships between exposure and hostility, and exposure and negative urgency. Analytic thinking moderates the relationships between maladaptive scripts and engagement. Findings were not supportive of the IP-DP model but suggest further testing.
2

Evidence that bats perceive wind turbine surfaces to be water

McAlexander, Aaron Michael 19 December 2013 (has links)
Large numbers of migratory tree bats are being killed at wind energy facilities across North America, and this rapidly growing source of renewable energy may pose a threat to bat populations. In 2012 and 2013 we conducted an ultrasound playback experiment, night vision surveys, and acoustic monitoring to determine if bats could be attracted to the smooth wind turbines surfaces because they perceive them to be water. Our playback experiment revealed little or no differences in the physical characteristics of echoes reflected from water and turbine surfaces. Our video and acoustic surveys indicated that bats behave at wind turbines as they do around water sources. Moreover, we observed bats attempting to drink from turbine towers at rates similar to water sources. Our data suggest that bats may be attracted to wind turbines because the surfaces produce an acoustic signature that is indistinguishable from water.
3

NEW APPLICATION OF ACRIDINE ORANGE TO STUDY BIOPHYSICS OF EXOCYTOTIC PROCESSES IN CELL

Shumilov, Dmytro 19 December 2013 (has links)
Mucus secretion is the first-line of defence against the barrage of irritants inhaled into human lungs, but abnormally thick and viscous mucus results in many respiratory diseases. Investigation of processes underlying mucus pathology is hampered, in part, by lack of appropriate experimental tools for labeling and studying mucin granule secretion from live cells with high sensitivity and temporal resolution. Fluorescence spectra and fluorescence lifetime of AO measurements reveal significant changes due to aggregation, and this properties can be useful for determination of mucus expansion. In this report I present original spectroscopic properties of acridine orange (AO) which could be utilized to study granule release and mucin swelling with novel fluorescence imaging approaches. To explore fluorescent properties we measured the quantum yield and extinction coefficient and lifetimes.
4

An analysis of anomalous meteorite, Enon: Classification and thermal history

Garcia, Sarah Lynn 19 December 2013 (has links)
Enon is an anomalous stony-iron meteorite having an affinity to both achondrites and ordinary chondrites. This study uses mineral chemistry, oxygen isotopes, and two-pyroxene geothermometry to understand Enon's formation history and to determine if it can be genetically related to any other known meteorite group. SEM mineral maps were used to identify texture and mineralogy, and detailed chemical analyses were obtained by electron microprobe. Oxygen isotope data was collected by analyzing powered olivine by infrared laser-assisted fluorination. The program QUILF was used to calculate the two-pyroxene closure temperature for Enon. Results indicate that Enon has approximately chondritic silicate compositions; an oxygen isotope composition similar to mesosiderites/HEDs; and experienced partial melting at the Fe, Ni-FeS eutectic and silicate recrystallization and major-element equilibration. This study suggests that Enon is a primitive achondrite that records the onset of igneous differentiation of its parent body.
5

UNMASKING A SILENT KILLER: UNCOVERING THE MECHANISM OF HEPATITIS C VIRUS PROTEIN NS5A MEDIATED INHIBITION OF THE INNATE IMMUNE RESPONSE

Wu, Wenjing 19 December 2013 (has links)
Hepatitis C Virus (HCV) is a human liver pathogen. In the host its infection leads to acute and chronic hepatitis, cirrhosis and hepatocellular carcinoma. This positive stranded RNA virus is extremely efficient in establishing persistent infection by escaping immune detection by hindering the host immune responses. An important component of the host’s innate immune response in viral infection is the production of type I interferons (IFNs). Typically, viral infection induces the synthesis and secretion of interferon α/β (IFN α/β) by the infected cell, which in turn activates signaling pathways leading to the establishment of an antiviral state in the cell. This raises the question of how HCV circumvents the antiviral immune responses of host cells. Previous studies have shown that HCV nonstructural protein NS3/4A interferes with the activation of signaling pathways that leads to the activation of the IFNβ. Our lab has identified another HCV protein, NS5A, that also interferes with host antiviral signaling independent of the NS3/4A-mediated inhibition of the host antiviral response. Activation of IFNβ gene expression involves the activation of three transcription factors (ATF-2, IRF3/7 and NF-κB) and the formation of an enhanceosome on the promoter. To investigate the influence of HCV NS5A on innate immunity, we study the effect of NS5A over-expression on Sendai Virus (SV)-mediated IFNβ gene induction via qPCR and reporter gene assay. We have identified NS5A to be a potent inhibitor of the host innate immune system, possibly through inhibition of IRF3 activation. We are currently investigating the effect of NS5A on transcription factor activation. NS5A inhibition of IFNβ induction, may be another factor contributing to the persistence of HCV in the host, and may play a key role in designing therapies for the treatment of HCV infection.
6

IMPACT OF NUCLEAR-MITOCHONDRIAL HYBRIDIZATION ON FITNESS AND OXIDATIVE STRESS IN CAENORHABDITIS BRIGGSAE AND C. SP. 9

Yockey, Mason 19 December 2013 (has links)
Abstract: IMPACT OF NUCLEAR-MITOCHONDRIAL HYBRIDIZATION ON FITNESS AND OXIDATIVE STRESS IN CAENORHABDITIS BRIGGSAE AND C. SP. 9 Mason John Yockey MS 2013 Department of Biology, Texas Christian University Dr. Phil Hartman, Professor, Dean of College of Science & Engineering Mitochondria are organelles contained in eukaryotic cells, which produce energy. Mitochondria are unique for several reasons, one being that they contain a small genome of their own, distinct from the main genome contained within the nucleus. Proper co-ordination between the nucleus and the mitochondria is vital for the functioning of the cell. A study was recently performed on several hybrid strains of Caenorhabditis nematodes which contained nuclear DNA from one lineage and mitochondrial DNA from another. Their fitness was tested by examining their growth, reproduction, lifespan under oxidative stress in the form of 95% oxygen. Results from these experiments appeared to show these trends: growth was typically suppressed, reproduction diminished, and lifespan slightly extended by the oxygen stress. These results might indicate the presence of a mitochondrial hormetic effect in these organisms.
7

Attachment Disturbances and Attachment Representations in At-Risk Adopted Children

Razuri, Erin E. 12 January 2007 (has links)
Although children adopted after deprivation or maltreatment are thought to be at-risk for attachment-related problems, little is known about the attachment representations thought to underlie attachment behavior. Further, methods of assessing attachment representations and attachment disturbances are needed. The current study examined the use of Family Drawings and the Beech Brook Attachment Disorder Checklist (BBADC) as assessments of attachment representations and attachment disordered behavior, respectively, in a sample of adopted children at-risk for behavior disturbances. The BBADC was correlated with the Child Behavior Checklist (CBCL), but contrary to expectations, Family Drawings were not related to scores on either the BBADC or CBCL. Scores on the BBADC improved after participation in a therapeutic camp. In addition, children who had higher Machiavellianism scores and those who used more color on their Family Drawings before camp had greater improvements in all BBADC factors after camp. Methodological and theoretical implications are discussed.
8

The Synthesis and Structural Characterization of Main Group and Transition Metal Complexes Supported by Nitrogen Based Ligands

Lesikar, Leslie 16 January 2009 (has links)
Nitrogen based monodentate and bidentate chelating ligands have captured a significant interest due to their ability to coordinate to a wide variety of elements. The â-diketimine, â-ketoiminato, formamidine, pyridineselenolate, and pyrazinecarboxamide ligands have all been employed in this study to further investigate the coordination preferences among main group and transition metals. Steric and electronic properties of these ligands can easily be altered by manipulating the substituents attached, thus leading to predictable structures with potential for many useful and significant applications. Investigations have shown that temperature, solvent, and metal halide employed are all key factors in the reaction outcomes. All of the complexes obtained throughout these studies have been characterized by X-ray crystallography along with other spectroscopic techniques, including NMR, IR, UV/Vis, and M/S. â-diketiminato ligands, [{N(R)C(Me)}2C(H)] where R = Dipp, Mes, commonly referred to as nacnac, have played an important role in the synthesis of novel pnictogenium complexes. Results show that through manipulation of the halide precursor, reaction stoichiometry, and the R substituent on the nacnac both N,N'- and N,C'-metal chelated complexes can be achieved. Additionally, â-ketiminato ligands, [RN(H)(C(Me))2C(Me)=O] where R = Dipp, and [RN(H)C(Me)CHC(Me)=O] where R = C2H4NEt2, have been studied. Both ligands were investigated with a range of d and p block metal halides and alkyls in order to compare and contrast the bulky, flexible, and even multi-dentate nature of each ligand. The preferred metal geometry remains constant for products with either ligand, but the steric protection offered by the individual ligands governs the nuclearity of the products, ranging from tetrameric cages to simple adducts. The formamidinate ligand, [RN(H)C(H)NR] where R = Dipp, was employed in synthesizing several aluminum and zinc complexes. In addition to their numerous applications as catalysts, the smaller ligand backbone is capable of N,N'-chelation analogously to the â-diketiminates and â-ketiminato ligands, as well as a variety of other coordination modes. The stoichiometric ratio of ligand to the metal alkyl was emphasized for these reactions affording aluminum and zinc formamidinate complexes exhibiting monodentate, bidentate, and bridging coordination modes. Lastly, the coordination of group 13 metal halides was investigated employing the pyridineselenolate, [HSe-2-NC5H4], and pyrazinecarboxamide, [(C4H3N2)CONH2], ligands. The research focused on the individual synthetic methods in the preparation of group 13 complexes.
9

Motivated Forgetting and Attitude Change

Morin, Amanda Leigh 16 January 2009 (has links)
Abstract Two experiments tested whether feigned memory loss for attitude-relevant actions can cause forgetting and decrease the impact of those actions on subsequently reported attitudes. Compared to participants in a control group, participants in Experiment 1 correctly recalled fewer of imagined attitude-relevant actions for which they feigned memory loss, and also displayed less effect of the imagined actions on their attitudes toward a social group. Compared to participants in a control group, participants in Experiment 2 had no memory impairments for self-generated arguments favorable or unfavorable to capital punishment after feigning memory loss for those arguments, but they displayed a greater effect of the arguments on subsequently reported attitudes. The discussion suggests reasons why results of the two experiments were discrepant.
10

The Effects of Microglial Inactivation and Decreased Prostaglandin Synthesis on Lipopolysaccharide-induced Learning Deficits

Tarr, Andrew Justin 08 March 2007 (has links)
Microglial inhibitors and non-selective COX inhibitors maybe possible treatments for neurodegenerative diseases such as Alzheimers disease, Parkinsons disease, and multiple sclerosis by reducing cytokine overexpression. Experiments 1 & 2 attempted to further the understanding of the mechanisms of how proinflammatory cytokines contribute to learning/memory deficits seen after lipopolysaccharide administration and to the extent to which microglial cells play a role in this. Specifically, the present study investigated the role of prostaglandin production and microglial activation in the development of LPS-induced cognitive impairments. Experiment 1 consisted of a co-administration of minocycline and LPS to C57BL/6J male mice. Experiment 2 consisted of a co-administration of indomethacin and LPS also to C57BL/6J male mice. We hypothesized that minocycline and indomethacin would reduce central cytokine levels and reduce or eliminate the effects of LPS-induced anxiety and cognitive deficits in both elevated plus maze and 2-way active avoidance conditioning paradigms.

Page generated in 0.1301 seconds