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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.
291

Hostitelská specifita, diverzita a distribuce malarických parazitů v kontaktní zóně dvou druhů slavíků / Host specificity, diversity and distribution of avian malaria parasites in a contact zone of two nightingale species

Šíma, Michal January 2011 (has links)
Avian contact zones were suggested to act as barriers to parasite expansions. I studied haemosporidian parasites (genera Plasmodium, Haemoproteus, and Leucocytozoon) of two Nightingale species which meet in a contact zone in Europe. In total 20 lineages of parasites were detected. Surprisingly, all common lineages were shared by the two host species. The parasite prevalence vary between species (Trush Nightingales were more often parasitized than Common Nightingales.) but did not vary to a large extent within zones inside species Parasitemia of the most frequent Haemoproteus LULU1 lineage assessed by Real-Time PCR method did not differ significantly between the two host species. Six out of nine hybrids of the nightingale species were parasitized. Haemosporidian lineages found in hybrids were also frequent in the parental species. In conclusion, the nightingale contact zone seems to have only little (if any) effect on the distribution of haemosporidian parasites.
292

Jednohostitelská trypanosomatida bezobratlých / Monoxenous trypanosomatids of invertebrates

Havlová, Jolana January 2017 (has links)
The class Kinetoplastea contains free-living and parasitic species. One of the most dominant group within the class is the order Trypanosomatida which includes obligate parasites (Trypanosoma, Leishmania) infecting a wide range of hosts. Some species are serious pathogens of humans and domestic animals and cause considerable losses. However, the majority of trypanosomatids belongs to monoxenous parasites of insect which are usually harmless to their hosts. Monoxenous trypanosomatids predominantly infect Hemiptera and Diptera. This diploma thesis is focused on the detection of monoxenous trypanosomatids in cockroaches captured in the Czech Republic and cockroaches from different breedings. Cockroaches are very suitable mechanical vectors of many different pathogens (including parasites) and are significant health threat for humans and animals. First trypanosomatids in cockroaches were documented at the beginning of the 20th century, but there is no study focused on this topic specifically. Another aim of this thesis is morphological and ultramicroscopic analysis and the study of the host specificity of the recently described species Herpetomonas tarakana, isolated from a cockroach. My findings were partly used in the already published study "Diversity of trypanosomatids in cockroaches and the...
293

Prioritering vid utlarmning i prehospital vård

Ek, Bosse January 2014 (has links)
It is important that ambulances are urgently directed to patients who are in need of immediate help and of quick transportation to a hospital. Because resources are limited, emergency medical dispatch centres (EMD) cannot send ambulances with high priority to all callers. The efficiency of the system is therefore dependent on triage. Increased knowledge about the triage in the prehospital care can make it possible to optimize the use of resources. Traditionally nurses have an important role in triage on emergency departments and in telephone advisory. In Sweden there is a trend towards more triage by nurses at EMDs. It is important to survey experiences of nurses’ of prioritization at EMDs. Aim: The overall aim in this thesis was to measure effectivity in prioritisation of ambulance dispatches, and to elucidate experiences from these prioritizations and decisions. Method: In study I sensitivity and specificity in 4086 dispatches was calculated, by comparison of the priority given by the EMD and the assessment performed by the ambulance-nurse according to Medical Emergency Triage and Treatment System. In study II were 15 nurses interviewed about their experiences from prioritizations at an EMD. Result: The result showed that 84,5 % of the dispatches were correct prioritised and that the sensitivity was high (94,5 %) but the specificity was low (15,4 %). Content analysis was performed and two themes emerged: “Having a profession with opportunities and obstacles” and “Meeting serious and difficult situations”. Conclusions are that over- prioritizations are made concerning patients with low or no need of medical care. Also that nurses with experience from emergency care, who are allowed to make their own decisions independent of the medical index, can improve and nuance the prioritization of resources in prehospital care. However, there is an obvious risk that their assessments will tend to be on the safe side. Important for avoiding this is improving internal support systems at the EMDs and also striving for a blame-free culture, where the nurses are not pushed by threats of being reported.
294

Attention and executive control during lexical processing in aphasia

Evans, William Streicher 03 November 2015 (has links)
The goal of this project was to investigate the relationship between executive attention and specific linguistic and control processes during goal-directed tasks in aphasia. Its central premise was that PWA often possess dissociable impairments in linguistic processes and in the mechanisms that control and efficiently utilize those processes. The motivation for this claim was based on observations that PWA often present with deficits in the online processing of linguistic information, which in some instances have been interpreted as evidence for impaired linguistic operations, but in others has been interpreted as evidence for impaired control of language processing due to more general cognitive constraints. The current work tested claims regarding the Executive Attention model (Engle and Kane, 2004) in aphasia and its relation to varying task sets in linguistic and nonlinguistic tasks. 20 PWA and 23 matched controls were tested on four tasks measuring executive attention in verbal and nonverbal domains using word-picture interference, semantic and perceptual go/no-go, and spatial Stroop designs. Participants were also tested on lexical decision and numerosity judgment tasks with varying speed and accuracy-focused instructions, with performance modeled using the Diffusion Model (Ratcliff, 1978). Overall, the current work found evidence for the predicted domain-general and domain-specific impairments in executive attention at the level of individual PWA. However, these executive attention deficits did not appear to be associated with difficulties adapting to shifting speed-accuracy constraints. In addition, group-level patterns of performance across experiments suggest an additional related executive control deficit in the area of generating and maintaining arbitrary stimulus-response mappings. This study also demonstrated the appropriateness and potential applicability of the diffusion model in aphasia research, and diffusion model analyses found that PWA had difficulty adjusting their nondecision times in response to speed constraints, had lower drift rates in lexical decision, which reflected inefficient processing of lexical information, and had a disproportionately difficult time efficiently processing easy stimuli in lexical and numerosity tasks.
295

Defining the Early, Mid, and Late Sub-Sections of Sprint Acceleration in Division I Men’s Soccer Players

Bellon, Christopher R., DeWeese, Brad H., Sato, Kimitake, Clark, Kenneth P., Stone, Michael H. 01 April 2019 (has links)
The purpose of this study was to investigate whether the acceleration phase of sprinting could be split into subphases specific to the competitive demands of a soccer match by comparing sprint metrics at various sprint distances in Division I men's soccer players. Twenty-three Division I men's soccer athletes completed 2 maximal-effort 20-m sprints from a standing start position through an optical measurement system. Sprint metrics measured included sprint velocity (SV), step length (SL), step frequency (SF), and ground contact time (GCT). Each metric was recorded at approximately 2.5, 6, and 12 m. Sprint metrics at each distance were compared using a 2-tailed, 1-way repeated-measures analysis of variance. The results indicated that SV, SL, and SF were statistically greater at 12 m in comparison with 6 m (p < 0.001) and 2.5 m (p < 0.001), whereas GCT was statistically shorter at 12 m compared with 6 m (p < 0.001) and 2.5 m (p < 0.001). In addition, sprint metrics at 6 m also displayed the same relationships when compared to 2.5 m, with SV, SL, and SF being statistically greater (p < 0.001) at this distance, and GCT being statistically shorter (p < 0.001) as well. These results suggest that the acceleration phase may effectively be differentiated into early, mid, and late subphases based on differences in key sprint metrics at distances of 2.5, 6, and 12 m, respectively, in Division I men's soccer athletes.
296

Universal Suicide Risk Screening in the Parkland Health and Hospital System: Evaluation of the Parkland Algorithm for Suicide Screening

Goans, Christian 08 1900 (has links)
Suicide is a significant public health issue in the US. Despite national and international prioritization since 1996, little definitive progress has been made in terms of identification and intervention in cases of elevated suicide risk. Forty percent of those who died by suicide attended an emergency department within a year of death. Therefore, universal suicide risk screening in emergency departments could prove a vital component to a national suicide prevention strategy. The present study empirically evaluated the universal suicide risk screening program recently implemented at Parkland Health and Hospital System. The sample consisted of patients over 18 years of age (N=333,855; Mage=42.7, 32% male) screened as part of routine clinical care from May 4th, 2015, through November 3rd, 2015. The Parkland Algorithm for Suicide Screening (PASS) is part of a clinical decision support system for responses to Columbia - Suicide Severity Rating Scale Clinical Practice Screener (C-SSRS) items, leading to an automated clinical response via three suicide risk stratification levels: no action for no risk identified, psychiatric social worker assessment for moderate risk identified, and psychiatrist/psychologist interview for high risk identified. The present study used receiver operating characteristic (ROC) curve analysis, which found the PASS predicted disposition (z=30.46, p<.001, AUC=.78, CI95=.77, .81). This study also evaluated the cutpoints separating suicide risk stratification and levels of clinical response. The results supported the first cutpoint and highlighted a need for additional data to address the second cutpoint. The results of the present study suggest that the universal suicide risk screening program at Parkland Health and Hospital System is an important step toward addressing suicide prevalence in the US.
297

In silico and in vitro determination of substrate specificity for Breast Cancer Resistance Protein (BCRP) transporter at the blood-brain barrier

Wang, Fen January 2021 (has links)
Background The Breast Cancer Resistance Protein (BCRP) drug transporter is important for drug disposition and plays a critical role in regulating drug entry into the brain. Its substrate spectrum overlaps with substrates of Multi Drug Resistance Protein 1 (MDR1, P-gp), which influences and complicates the interpretation of data on drug distribution into tissues (e.g. brain). Distinguishing BCRP mediated transport from the transport by the MDR1 is often problematic. However, with new in vitro tools, this is now possible. In this project, two drug compounds, i.e. Dantrolene and Ritonavir, were investigated using these new in vitro models. The results from the experimental in vitro assay were matched with molecular dynamics (MD) simulations. Using coarse-grained (CG) simulations, a model of the BCRP transporter in a lipid bilayer was built, this model is based on the human BCRP structure revealed by Taylor et al (2017). Simulations were run for Dantrolene (a known substrate of BCRP) independently three times, and another with Ritonavir (a non-substrate) three times. Aim To determine substrate specificity for the BCRP transporter for two compounds, and to construct a CG model of BCRP transporter to see whether in silico methods can be used as an alternative for assessing substrate specificity.  Methods Madin-Darby canine kidney (MDCK) II cell line with no endogenous canine MDR1 (cMDR1) expression (MDCKcMDR1-KO), overexpressing human MDR1 (hMDR1) (MDCK-hMDR1cMDR1-KO) and stable expression of human BCRP (hBCRP) (MDCK-hBCRPcMDR1-KO) cells were cultured and used in Transwell experiments. Samples were analyzed using LC-MS/MS to determine the substrate concentrations. Apparent permeability and efflux ratio was calculated and evaluated.  MD simulations used the Martini 3 CG force field, and were run with Gromacs (version 2020.4). Tools including MODELLER, INSANE and others were used to construct the initial model (Webster, 2000; Wassenaar et al., 2015), for parameterization of substrate and non-substrate molecules. And visual inspection was done with the visual molecular dynamics (VMD) program and PyMOL. Results In vitro transport experiment confirmed that Dantrolene is a BCRP specific substrate, and Ritonavir is MDR1 specific substrate. Following simulations of these two compounds, Dantrolene is observed to stay in the transmembrane domains (TMD) for a certain period (on average several hundreds of nanoseconds), while Ritonavir is not found to bind in the TMD, which provides a proof of concept for future studies.
298

Denaturants or Cosolvents Improve the Specificity of PCR Amplification of a G + C-Rich DNA Using Genetically Engineered DNA Polymerases

Varadaraj, Kulandaiappan, Skinner, Dorothy M. 01 January 1994 (has links)
We describe conditions that improve the specificity of amplification of a G + C-rich (57% G + C) DNA by PCR. Under standard conditions a 368-bp segment of the approx. 2.1-kb repeat unit of a satellite DNA that accounts for approx. 3% of the genome of the Bermuda land crab, Gecarcinus lateralis, was not amplified specifically. To establish optimal conditions for amplification of the segment of the G + C-rich satellite, we used two genetically engineered enzymes, AmpliTaq DNA polymerase and AmpliTaq DNA polymerase. Stoffel fragment (SF), and a number of denaturants or co-solvents. In the absence of denaturants or co-solvents, amplified products of both enzymes contained non-specific bands upon gel electrophoresis. Addition of certain denaturants or co-solvents to PCR mixtures resulted in the production of the single specific band of the expected size. Reagents that improved specificity of the amplified product were formamide, glycerol, DMSO, Tween-20 and NP-40; on the other hand, urea, ethanol and 1-methyl-2-pyrrolidone (NMP) inhibited amplification. Of the two enzymes, SF was more specific and efficient. The products of AmpliTaq DNA polymerase included one or more extra bands, even in the presence of denaturants or co-solvents, except for glycerol or DMSO.
299

Sex Chromosome-Wide Association Analysis Suggested Male-Specific Risk Genes for Alcohol Dependence

Zuo, Lingjun, Wang, Kesheng, Zhang, Xiangyang, Pan, Xinghua, Wang, Guilin, Krystal, John H., Zhang, Heping, Luo, Xingguang 01 December 2013 (has links)
BACKGROUND: Alcohol dependence is more common among men than among women. Potential explanations for this include the role of genes in sex chromosomes (X and Y). In the present study, we scanned the entire Y chromosome and its homologs on the X chromosome in men to identify male-specific risk genes for alcohol dependence. METHODS: Two thousand nine hundred and twenty-seven individuals in two independent cohorts were analyzed. The European-American male cohort (883 cases with alcohol dependence and 445 controls) served as the discovery cohort and the European-American female cohort (526 cases and 1073 controls) served as a contrast group. All individuals were genotyped on the Illumina Human 1M beadchip. Two thousand two hundred and twenty-four single nucleotide polymorphisms (SNPs) on the Y chromosome or in the homologs on the X chromosome were analyzed. The allele frequencies were compared between cases and controls within each cohort using logistic regression analysis. RESULTS: We found that, after experiment-wide correction, two SNPs on the X chromosome were associated significantly with alcohol dependence in European-American men (P=1.0×10 for rs5916144 and P=5.5×10 for rs5961794 at 3′ UTR of NLGN4X), but not in the women. A total of 26 SNPs at 3′UTR of or within NLGN4X were nominally associated with alcohol dependence in men (5.5×10≤P≤0.05), all of which were not statistically significant in women. CONCLUSION: We conclude that NLGN4X was a significant male-specific risk gene for alcohol dependence in European-Americans. NLGN4X might harbor a causal variant(s) for alcohol dependence. A defect of synaptogenesis in neuronal circuitry caused by NLGN4X mutations is believed to play a role in alcohol dependence.
300

Sex Chromosome-Wide Association Analysis Suggested Male-Specific Risk Genes for Alcohol Dependence

Zuo, Lingjun, Wang, Kesheng, Zhang, Xiangyang, Pan, Xinghua, Wang, Guilin, Krystal, John H., Zhang, Heping, Luo, Xingguang 01 December 2013 (has links)
BACKGROUND: Alcohol dependence is more common among men than among women. Potential explanations for this include the role of genes in sex chromosomes (X and Y). In the present study, we scanned the entire Y chromosome and its homologs on the X chromosome in men to identify male-specific risk genes for alcohol dependence. METHODS: Two thousand nine hundred and twenty-seven individuals in two independent cohorts were analyzed. The European-American male cohort (883 cases with alcohol dependence and 445 controls) served as the discovery cohort and the European-American female cohort (526 cases and 1073 controls) served as a contrast group. All individuals were genotyped on the Illumina Human 1M beadchip. Two thousand two hundred and twenty-four single nucleotide polymorphisms (SNPs) on the Y chromosome or in the homologs on the X chromosome were analyzed. The allele frequencies were compared between cases and controls within each cohort using logistic regression analysis. RESULTS: We found that, after experiment-wide correction, two SNPs on the X chromosome were associated significantly with alcohol dependence in European-American men (P=1.0×10 for rs5916144 and P=5.5×10 for rs5961794 at 3′ UTR of NLGN4X), but not in the women. A total of 26 SNPs at 3′UTR of or within NLGN4X were nominally associated with alcohol dependence in men (5.5×10≤P≤0.05), all of which were not statistically significant in women. CONCLUSION: We conclude that NLGN4X was a significant male-specific risk gene for alcohol dependence in European-Americans. NLGN4X might harbor a causal variant(s) for alcohol dependence. A defect of synaptogenesis in neuronal circuitry caused by NLGN4X mutations is believed to play a role in alcohol dependence.

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