• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 170
  • 108
  • 65
  • 28
  • 28
  • 11
  • 8
  • 7
  • 5
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 522
  • 122
  • 72
  • 68
  • 61
  • 48
  • 45
  • 45
  • 36
  • 33
  • 32
  • 31
  • 30
  • 29
  • 28
  • 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.
211

Algorithms for antibiotic susceptibility testing for pathogens causing sepsis

Åhag, Stina January 2017 (has links)
This study is a part of a project at Q-linea that aims to present a rapid diagnostic instrument to speed up the process of identification of pathogens and determination of MIC-values (Minimal Inhibitory Concentration) of antibiotic needed to treat patients with sepsis. Specifically, this report is aimed to describe the development and implementation of algorithms that examine susceptibility profiles ofsepsis related pathogens where the bacteria have been exposed to different antibiotics and by different lapse of concentrations. The developed algorithms are based on a clustering technique that identify inhibited growth and present the lowest concentration needed to slow down the growth of the pathogen. The implemented solution was tested on sepsis related pathogens and the determined MIC values were compared to MIC values generated with a method commonly used in healthcare today. Approximately 90% of instances were correctly classified based on data from six hours long tests which is significantly faster than the reference method which takes 16-24 hours to complete. Furthermore, each result comes with a set of quality measures for validation of the algorithm results. Although, further studies are necessary to increase the performance at the four-hour target time, and more data is needed to validate the developed quality measures.
212

Macrophage Migration Inhibitory Factor and Myeloid Derived Suppressor Cell Function in Oral Carcinogenesis

Ryan, Nathan M. 04 October 2021 (has links)
No description available.
213

Age-Related Differences in Food-Specific Inhibitory Control: Electrophysiological and Behavioral Evidence in Healthy Aging

Allen, Whitney D. 28 April 2022 (has links) (PDF)
The number of older adults is estimated to double from 52 million to 95 million by 2060. Approximately 80-85% of older adults are diagnosed with a chronic health condition. Many of these chronic health conditions are influenced by diet and exercise, suggesting improved diet and eating behaviors could improve health-related outcomes. One factor that might improve dietary habits in older adults is food-related inhibitory control. We tested whether food-related inhibitory control, using behavioral (response time, error rate) and scalp-recorded event-related potential (ERP; N2 and P3 components) measures of food-related inhibitory control differed between younger and older adults over age 55. Fifty-nine older adults (31 females [52.5%], Mage=64, SDage=7.5) and 114 younger adults (82 females [71.9%], Mage=20.8) completed two go/no-go tasks, one inhibiting to high-calorie stimuli and one inhibiting to low-calorie stimuli, while electroencephalogram (EEG) data were recorded. Older adults had slower overall response times than younger adults, but this was not specific to either food task. There was not a significant difference for accuracy between younger and older adults, but both groups' accuracy and response times were significantly improved during the high-calorie task than the low-calorie task. For both the N2 and P3 ERP components, younger adults had greater amplitude than older adults, but this effect was not food-specific, reflecting overall generalized lower inhibitory processing in older adults. Of note, P3 amplitude for the younger adults demonstrated a specific food-related effect (greater P3 amplitude for high-calorie no-go) that was not present for older adults. Findings support previous research demonstrating age related differences in inhibitory control though those differences may not be specific to inhibiting to high-calorie foods.
214

Synergistic Control of Transmitter Turnover at Glycinergic Synapses by GlyT1, GlyT2, and ASC-1

Eulenburg, Volker, Hülsmann, Swen 07 February 2024 (has links)
In addition to being involved in protein biosynthesis and metabolism, the amino acid glycine is the most important inhibitory neurotransmitter in caudal regions of the brain. These functions require a tight regulation of glycine concentration not only in the synaptic cleft, but also in various intracellular and extracellular compartments. This is achieved not only by confining the synthesis and degradation of glycine predominantly to the mitochondria, but also by the action of high-affinity large-capacity glycine transporters that mediate the transport of glycine across the membranes of presynaptic terminals or glial cells surrounding the synapses. Although most cells at glycine-dependent synapses express more than one transporter with high affinity for glycine, their synergistic functional interaction is only poorly understood. In this review, we summarize our current knowledge of the two high-affinity transporters for glycine, the sodium-dependent glycine transporters 1 (GlyT1; SLC6A9) and 2 (GlyT2; SLC6A5) and the alanine–serine–cysteine-1 transporter (Asc-1; SLC7A10).
215

The Relationship Between Family SES and Executive Functions: Exploring a Mediated Mediation Model

Rubez, Doroteja 27 January 2023 (has links)
No description available.
216

Organization of prefrontal and premotor layer-specific pathways in rhesus monkeys

Bhatt, Hrishti 16 February 2024 (has links)
The Lateral Prefrontal Cortex (LPFC) and the Dorsal Premotor cortex (PMd) are two cortical structures that are involved in cognitive processes such as motor planning and decision-making. The LPFC is extensively connected to sensory, somatosensory, and motor cortices that help it control several cognitive functions [for review, see: (Tanji & Hoshi, 2008)]. Similarly, the PMd can integrate information from the prefrontal and motor cortex, acting as a link, in action planning and decision making [for review, see: (Hoshi & Tanji, 2007)]. Therefore, it is important to study the cortical pathways between these areas because of their common role in processing and selecting relevant information in tasks requiring decision-making. Using neural tract-tracing, immunolabeling and microscopy in rhesus monkeys (M. mulatta), we assessed the distribution and layer-specific organization of projection neurons from LPFC area 46 and PMd area 6 directed to the LPFC area 9. Our study revealed that projection neurons to area 9 were found originating from upper (L2-3) and deep (L5-6) layers of both areas, but with a slight upper layer bias. We found that the LPFC area 46 had a higher density of projection neurons directed to LPFC area 9 compared to the PMd area 6. Additionally, our data also revealed laminar differences in the perisomatic parvalbumin (PV) inhibitory inputs onto area 9 projection neurons, which were dependent on area of origin. Within ventral LPFC area 46, perisomatic PV+ inhibitory inputs onto upper layer projection neurons to area 9 was greater than those onto deep layer projection neurons. The opposite pattern was found for PMd area 6DR, where perisomatic PV+ inhibition onto deep layer projection neurons to area 9 was greater than those onto upper layer neurons. These findings provide additional insights into the layer-specific organization of prefrontal and premotor pathways that play an important role in action planning and decision-making.
217

Analysis of candidate soluble and cellular biomarkers in patients with axial spondyloarthritis compared to chronic low back pain and healthy controls

Bauchiero, Caroline Grace 14 February 2024 (has links)
BACKGROUND: Distinguishing patients with axial spondyloarthritis (axial SpA) from patients with other causes of chronic back pain remains a challenge. The lack of reliable biomarkers contributes to the diagnostic delay in axial SpA. Recently, macrophage migration inhibitory factor (MIF) has been proposed as a candidate diagnostic and prognostic biomarker. MIF is a proinflammatory cytokine that was shown to be upregulated in several autoimmune diseases, including axial SpA. The putative role of CD8+ T cells in the disease process suggests further that serum markers of cytotoxicity might have value as serological biomarkers in axial SpA, and that subpopulations of cytotoxic lymphocytes might deserve attention as candidate cellular biomarkers. OBJECTIVE: The goal of this study was to compare serum levels of MIF and other candidate serum proteins in patients with axial SpA and controls, and to develop a flow cytometry panel to analyze cytotoxic lymphocyte cell subpopulations in these cohorts, including KIR+CD8+ T cells, Granzyme B+ CD8+ T cells, MAIT cells, and InEx cells. METHODS: Study subjects were recruited from the Brigham and Women’s Hospital Orthopedic and Arthritis Center. Four cohorts were compared: healthy controls (HC), patients with chronic low back pain (cLBP), axial SpA patients not on a biologic (axSpA/-), and axial SpA patients treated with a TNF inhibitor (axSpA/TNFi). Study subjects were matched for age, sex, and race, when possible. Serum was evaluated using the LEGENDplex Human CD8/NK panel (BioLegend) for thirteen markers including IL-17A, IL-6, TNF, granzyme B, and perforin. CRP and MIF were evaluated by DuoSet ELISA (R&D Systems). A high-dimensional flow cytometry panel was designed to evaluate 14 cell populations of interest. RESULTS: The severity of back pain in the cLBP controls and axSpA/- patients was comparable (BASDAI Q2 mean 5.0 +/- 1.9 vs. 5.0 +/- 3.0). axSpA/- patients had higher back pain, BASDAI and ASDAS scores than axSpA/TNFi patients consistent with higher disease activity in the biologic naïve group. Serum CRP values were significantly higher in axSpA/- patients compared with HC, cLBP controls, and axSpA/TNFi patients (P= 0.01, P=0.0029, P=0.004 respectively). Serum MIF levels were not statistically different between all four groups (P= 0.8069). Additionally, there were no statistically significant differences between the groups for any of the markers included in the LEGENDplex Human CD8/NK panel. A 32-color staining panel was developed to evaluate cytotoxic cell populations. CONCLUSION: In contrast to a previous study, we did not find differences in serum MIF levels between axial SpA patients and controls. Of the evaluated serum biomarkers, only CRP values correlated with active axial SpA. We have developed a promising flow cytometry panel that will help analyze subpopulations of cytotoxic cells. This ultimately could shed light on a candidate cellular biomarker. Our results underscore the need for more research into diagnostic biomarkers in axial SpA.
218

Analysis of T cell subsets in systemic sclerosis patients reveals altered composition and features of dysfunction

Volfson Sedletsky, Victoria 26 January 2024 (has links)
Systemic sclerosis (SSc) is a complex autoimmune connective tissue disorder. SSc presents with severe pathological clinical manifestations, including vasculature abnormalities, dysregulation of the immune system, and excessive extracellular matrix deposition that results in tissue fibrosis. How immune system abnormalities impact SSc remains poorly understood. Here we sought to explore the role of co-inhibitory receptors (co-IRs), which are important regulators of autoimmune responses. Previous studies showed altered co-IR expression in various autoimmune diseases, including SSc. Here we show that T cells co-expressing the co-IRs programmed cell death protein 1 (PD-1) and T cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT) are expanded in lung tissue obtained from SSc patients, as compared to healthy controls (HC). Furthermore, we found a significant association between the frequency of PD-1+TIGIT+ CD4+ T cells and lung disease in SSc patients. In addition, PD-1+TIGIT- and PD-1+TIGIT+ CD4+ cells in SSc patients showed an altered balance in cytokine production, characterized by reduced secretion of Interferon-γ, a cytokine with known anti-fibrotic properties, and increased levels of Interleukin-4, which is known for its pro-fibrotic activities. To test the impact of this changed cytokine balance on fibroblast biology, we co-cultured PD-1+TIGIT- and PD-1+TIGIT+ CD4+ T cells with normal dermal fibroblasts and found that PD-1+TIGIT- and PD-1+TIGIT+ T cells from SSc patients showed a reduced capacity to suppress collagen production, compared to the same subsets from HC subjects. Thus, co-IR-expressing T cells from SSc patients show features of dysfunction and may have lost anti-fibrotic activities. To further define the phenotype and functions of co-IR-expressing T cells subsets in SSc patients, we next designed a comprehensive immunophenotyping panel for full spectrum flow cytometry (FSFC) that included detection of lineage-defining transcription factors. Using this novel panel and an unbiased analysis approach, we compared T cell subset composition in peripheral blood mononuclear cells from HC subjects, and SSc and systemic lupus erythematosus (SLE) patients. Our analysis revealed broad shifts such as a decrease in the naïve CD4+ and CD8+ T cell compartment in SSc and in SLE patients. Importantly, changes in specific T cell subsets that were discovered in SLE patients, but not SSc patients, had a broad increase in T helper (Th)1 and T cytotoxic (Tc)1 subsets and a decrease in Th2/Tc2 subsets compared to HC subjects. Interestingly, we found a distinct Tc1 subset with exhaustion characteristics that was significantly reduced in both SSc and SLE patients compared to HC subjects. In the γδ T cell population, we found that while T-bet+ Vδ2 cells were decreased in SSc and SLE patients, the T-bet+ Vδ1 subset showed proliferative characteristics and was increased in SLE. Importantly, our analysis revealed differences in specific T cell subsets between SSc patients treated with immunosuppressants vs untreated patients, including an increase in Th17 cells in diffuse cutaneous SSc (dcSSc) patients that were not treated with immunosuppressants, and an increase in memory regulatory T cells in both dcSSc and limited cutaneous SSc (lcSSc) patients that were not treated with immunosuppressants. Our study demonstrates the value of a multiparameter FSFC panel in the identification of differentially represented and novel subsets of T cells in SSc and other autoimmune diseases. We demonstrated that T cell subset composition is altered in the peripheral blood of SSc patients and show that features of specific T cell subsets’ dysfunction are potentially contributing to SSc pathophysiology.
219

Cerium oxide nanoparticles for the detection of antimicrobial resistance

Noll, Alexander J. 01 May 2011 (has links)
The rise of antimicrobial resistance demands the development of more rapid screening methods for the detection of antimicrobial resistance in clinical samples to both give the patient the proper treatment and expedite the treatment of patients. Cerium oxide nanoparticles may serve a useful role in diagnostics due to their ability to exist in a mixed valence state and act as either oxidizing agents or reducing agents. Considering that cerium oxide nanoparticles have been shown to shift in absorbance upon oxidation, a useful method of antimicrobial resistance detection could be based on the oxidation of cerium oxide nanoparticles. Herein, an assay is described whereby cerium oxide nanoparticle oxidation is a function of glucose metabolism of bacterial samples in the presence of an antimicrobial agent. Cerium oxide nanoparticles were shown to have an absorbance in the range of 395nm upon oxidation by hydrogen peroxide whereas mixed valence cerium oxide nanoparticles lacked an absorbance around 395nm. In the presence the hydrogen peroxide-producing glucose oxidase and either increasing concentrations of glucose or bacterial medium supplemented with increasing concentrations of glucose, cerium oxide nanoparticles were shown to increase in absorbance at 395nm. This oxidation assay was capable of measuring differences in the absorbance of E. coli and S. aureus samples grown in the presence of inhibitory and non-inhibitory concentrations of ampicillin in as little as six hours. Therefore, this cerium oxide nanoparticle oxidation assay may be very useful for use in clinical laboratories for the detection of antimicrobial resistance due to the relatively low cost, no requirement for specialized equipment and, most importantly, the reduced incubation time of the assay to as little as six hours compared to current gold standard antimicrobial resistance detection methods that require 24 hours.; This assay may thus also help partially circumvent the issue of knowledge of antimicrobial resistance in infected patients before prescribing improper regimens.
220

The Impact of Sleep Restriction on Food-Related Inhibitory Control and Food Reward in Adolescents: Physical Activity and Weight Status as Potential Moderators

Duraccio, Kara McRae 01 June 2019 (has links)
The present study aimed to evaluate associations between sleep duration and food-related inhibitory control and food reward in adolescents aged 12-18. Potential moderating effects of physical activity and weight status on the association between sleep, inhibitory control, and food reward were also examined. To evaluate these associations, the study employed a two-phase crossover design in which participants spent either 5 hours per night (restricted sleep) or 9 hours per night (habitual sleep) in bed for 5 nights. Participants completed a food-related inhibitory control task and a questionnaire assessing for food reward on the 6th day of each study phase. Repeated measures analyses of variance examined the effect of sleep restriction on food-related inhibitory control and food reward, and explored the moderating impact of weight status and physical activity. Adolescents performed more poorly on a food-related inhibitory control task and have heightened food reward following sleep restriction. Though no differences were noted across weight status in performance of a food inhibitory control task, adolescents with overweight/obesity demonstrated heightened food reward. An interaction between sleep duration and weight status predicted food reward, indicated that normal-weight adolescents are more susceptible to heightened food reward following sleep restriction compared to overweight/obese adolescents. Conversely, overweight/obese adolescents showed consistently high food reward with no effect of sleep duration, suggesting that they consistently view food as rewarding. These study findings may suggest that shortened sleep duration increased food reward for normal weight individuals, potentially putting them at risk for development of overweight/obesity.

Page generated in 0.028 seconds