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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.
261

Low Frequency Oscillations of Hemodynamic Parameters as a Novel Diagnostic Measure for Traumatic Brain Injury

Gomez Carrillo, Andrea 24 August 2021 (has links)
No description available.
262

Bilateral Muscle Oxygenation Kinetics In Response To Repeat Sprint Cycling In Strong And Weak Individuals

Abbott, John 01 May 2020 (has links)
Repeat sprint ability has been investigated thoroughly, however optimal training methodology to improve RSA remains elusive. Both kinetic and physiological viewpoints have been used to scrutinize aspects of RSA including, initial sprint performance (anaerobic power), maximal cardiorespiratory fitness (VO2max), lactate threshold, anaerobic capacity (mean power), muscle activation (EMG), and local muscle oxygenation kinetics. To our knowledge no study has utilized maximal strength levels as a separate factor among a homogenous group of cardiorespiratory fitness individuals (as determined by peak VO2 during RSA). The purpose of this study was to better understand the relationship between maximal strength, muscular characteristics, and cycling RSA- respective to muscle oxygenation responses. Fifteen participants completed fifteen 10-second maximal effort sprints on a cycle ergometer interspersed with 30-seconds passive recovery. Respiratory, muscle oxygenation, and kinetic responses were monitored continuously and evaluated relationships with maximal strength and muscular architecture as determined by isometric mid-thigh pull and ultrasonography respectively. A series of 2 x 15 mixed design, group x time, ANOVA’s were used to evaluate the effects of group and or sprint on muscle oxygenation kinetics. Strong individuals were found to have significantly greater levels of muscle oxygenation usage, recovery and the respective rates; p = 0.01, p = 0.02, p
263

Two Near-Infrared Spectroscopic Studies of Ultracool Dwarfs: A Proper Motion Survey Follow-Up and A High-Resolution Investigation

Greco, Jennifer J. January 2020 (has links)
No description available.
264

Advancements in the Synthesis and Application of Near-Infrared Imaging Reagents: A Dissertation

Pauff, Steven M. 23 January 2015 (has links)
Fluorescence-based imaging techniques provide a simple, highly sensitive method of studying live cells and whole organisms in real time. Without question, fluorophores such as GFP, fluorescein, and rhodamines have contributed vastly to our understanding of both cell biology and biochemistry. However, most of the fluorescent molecules currently utilized suffer from one major drawback, the use of visible light. Due to cellular autofluorescence and the absorbance of incident light by cellular components, fluorescence imaging with visible wavelength fluorophores often results in high background noise and thus a low signal-to-noise ratio. Fortunately, this situation can be ameliorated by altering the wavelength of light used during imaging. Near-infrared (NIR) light (650-900 nm) is poorly absorbed by cells; therefore, fluorophores excited by this light provide a high signal-to-noise ratio and low background in cellular systems. While these properties make NIR fluorophores ideal for cellular imaging, most currently available NIR molecules cannot be used in live cells. The first half of this thesis addresses the synthetic difficulties associated with preparing NIR fluorophores that can be used within living systems. Small molecule NIR fluorophores are inherently hydrophobic which makes them unsuitable for use in the aqueous environment of the cell. Water-solubility is imparted to these dyes through highly polar sulfonates, which subsequently prevents the dyes from entering the cell. The novel work presented here details vii synthetic routes to aid in the development of sulfonated NIR fluorophores, which can be delivered into live cells through the inclusion of an esterase-labile sulfonate protecting group. Application of these synthetic techniques should allow for the development of novel NIR fluorophores with intracellular applications. The second half of this thesis addresses the need for novel NIR imaging reagents. Although several classes of NIR scaffolds do exist, most NIR probes are derivatives of a single class, heptamethine indocyanines. The work described here increases this palette by displaying the ability of NIR oxazines to function as an imaging reagent in live cells and in vivo and as a molecular sensor of biologically-relevant environmental conditions. Combined, the work contained herein has the capacity to not only advance the current NIR toolkit, but to expand it so that fluorescence imaging can move out of the dark and into the NIR light.
265

The role of alternating bilateral stimulation in establishing positive cognition in EMDR therapy: a multi-channel near-infrared spectroscopy study / EMDR療法での肯定的認知の構築における左右交互刺激の役割:多チャンネル近赤外線分光法を用いた研究

Amano, Tamaki 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第20294号 / 人健博第42号 / 新制||人健||4(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 二木 淑子, 教授 精山 明敏, 教授 村井 俊哉 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM
266

Prediction of Plastic Fragments in Recycled Paper Using Near-Infrared Spectroscopy

Alieva, Fidan January 2023 (has links)
Sustainability has gained a lot of attention in the field of research. Researchers and consumers both prioritize sustainability and environmental issues over previously dominant materials, such as plastic. Packaging and disposable items that used to be made of plastic have largely been replaced with paper. Unfortunately, paper does not perform as well as plastic regarding barrier properties against grease, oxygen, or water vapor. Barrier properties are an important factor when choosing packaging material for food, among other things, as they help maintain the shelf life of the product. In order to improve the properties of the paper packaging and expand its use, the paper is coated with a polymer. However, the polymer contributes to challenges in the recycling of the products as some of the polymer attaches to the fibers, causing difficulties in the separation of each material. Small fragments of plastic may end up in the material streams and the recycled pulp due to the existing challenges in completely removing plastic from cellulosic substrates during recycling. This thesis analyzes the possibilities of identifying and classifying plastic fragments of polyethylene (PE) and polyvinyl alcohol (PVOH) in recycled paper sheets using near-infrared spectroscopy together with multivariate data analysis. The purpose of the work is to develop models that can identify possible residues that may appear in recycled products from various industries. Paper sheets of two different grammages and six different compositions of recycled fiber and virgin fiber were created and scanned by NIR, with and without plastic film under the sheets. The scans were used to develop classification models to identify and categorize scans not included in the calibration data set. The performance of the models was tested by applying them to images of sheets of paper with plastic fragments of different sizes and different type underneath. The results indicated potential in the method. The prediction of the paper sheets with a lower grammage was mostly correct, whereas the classification of polyethylene showed the best performance. There was some noise in the prediction of the plastic fragments, regardless of the grammage of the paper. The noise may be due to a wide variation in the calibration data set since it consisted of paper sheets of six different compositions. A large part of the noise was incorrectly classified as polyvinyl alcohol, which can be due to differences in the manufacturing process of the plastic films. The conclusion of the thesis is that it is feasible to identify and categorize plastic fragments of polyethylene and polyvinyl alcohol in recycled paper sheets with a certain margin of error. It can be stated that the method shows promise, but further research and development in the field is required to build models that can be applied to a wider range of samples.
267

Comparison of muscle oxygen kinetics between occluded and non-occluded dynamic low-intensity exercise performed till failure : A quantitative study / Jämförelse av muskulär syreomsättning mellan ockluderad och icke-ockluderad lågintensiv dynamisk träning till failure : En kvantitativ studie

Smith, Natalie, Johansson, Josefine January 2023 (has links)
Aim: To examine local muscle oxygen kinetics when performing wrist extensions till failure in an occluded versus non-occluded state, to compare the perceived ratings of pain and local muscle exertion, and analysing presence of gender differences. Methods: Twenty-one healthy individuals (mean age 25,6±3.2, 10 females) performed wrist extensions at 30% of peak isometric strength till failure. The order in which the states was performed was randomized. The oxygen kinetics in the m. extensor digitorum was analysed using Near-infrared spectroscopy continuously. Ratings of perceived pain and local muscle exertion were collected before exercise, when reaching failure and post exercise recovery. Result: No difference was identified in tissue oxygen saturation (TOI) at the exercise plateau (-24.0±18.3% vs -23.5±13.9%, p=0.609). TOI at rest was lower for the occluded state (64.2±4.5% vs 57.2±5.9%, p<0.001). During the second minute of recovery, there was a greater increase in TOI for the occluded state (0.01±0.01%/sec vs 0.04±0.03/sec, p<0.001). A higher rating of perceived pain was found for the occluded state during baseline (0.0±0.0 vs 0.7±0.9, p=0.005) and first minute of recovery post exercise (2.3±2.0 vs 3.3±2.1, p=0.011). No clinically relevant gender differences were found. Conclusion: Venous occlusion during low-intensity dynamic wrist extensions affects the local oxygen kinetics in the muscle before and after exercise. The oxygenation kinetics does not differ when exercise plateau is reached when both regimes are performed till failure. This suggests that performing low-load dynamic wrist extensions in a no-relaxation manner, may have the same effects no matter whether occlusion is used or not. / Syfte: Att undersöka den lokala syreomsättningen i muskeln när handledsextensioner utförs till failure i ockluderat tillstånd jämfört med icke-ockluderat tillstånd, samt att jämföra den skattade upplevda smärtan och lokala muskelansträngningen, och eventuella skillnader mellan könen. Metod: Tjugoen friska individer (medelålder 25.6±3.2, 10 kvinnor) utförde handledsextentioner på 30 % av maximal isometrisk styrka till failure. Ordningen av ocklusion och icke-ocklusion var randomiserad. Nära-infraröd spektroskopi användes för att undersöka syreomsättningen lokalt i m. extensor digitorum. Skattning av upplevd smärta och lokal muskelansträngning samlades in före träning, vid failure och vid återhämtning efter träning. Resultat: Ingen skillnad identifierades i vävnadssyremättnad (TOI) vid uppnådd träningsplatå (-24.0±18.3% vs -23.5±13.9%, p=0.609). TOI i vila var lägre för det ockluderade tillståndet (64.2±4.5% vs 57.2±5.9%, p <0.001). Under den andra återhämtningsminuten var det en större ökning av TOI för det ockluderade tillståndet (0.01±0.01%/sek vs 0.04±0.03/sek, p <0.001). En högre skattning av upplevd smärta sågs för det ockluderade tillståndet under den första vilominuten (0.0±0.0 vs 0.7±0.9, p=0.005) och första minuten av återhämtning (2.3±2.0 vs 3.3±2.1, p=0.011). Inga kliniskt relevanta skillnader mellan könen hittades. Slutsats: Ocklusion under lågintensiva dynamiska handledsextensioner påverkar den lokala syreomsättningen i muskeln före och efter träning. Den muskulära syreomsättningen skiljer sig däremot inte när träningsplatå uppnås när båda regimerna utförs till failure. Detta tyder på att utförande av dynamiska handledsextensioner på låg belastning utan att muskeln tillåts att slappna av, kan ge samma effekter oberoende av om ocklusion appliceras eller inte.
268

Efekt ponořování předloktí do studené vody na opakované izometrické kontrakce flexorů prstů do vyčerpání u sportovních lezců / Effect of cold water immersion on intermittent isometric forearm flexor contractions to failure in rock climbers

Kodejška, Jan January 2018 (has links)
Title: Effect of cold water immersion on intermittent isometric forearm flexor contractions to failure in rock climbers Objectives: The aim of this study was to determine the effect of cold water immersion on intermittent isometric forearm flexor contraction to failure in rock climbers. Methods: Thirty-two climbers (15 male and 17 female) completed three intermittent trials to failure, on a climbing-specific handgrip dynamometer, on three separate visits to the laboratory. For each visit a different recovery strategy was employed: passive recovery (PAS), cold water immersion at 8 řC (CWI 8) or 15 řC (CWI 15). The force time integral (FTI - time of contraction multiplied by the force of contraction) was determined to assess intermittent performance. The tissue saturation index (TSI) and total haemoglobin (tHb) during isometric contractions from near-infrared spectroscopy (NIRS) were determined to assess hemodynamic changes. Differences between repeated trials and three recovery protocols, derived parameters NIRS, were assessed using repeated measures ANOVA with Bonferroni corrections. Results: There was no significant difference between conditions after trial one. In response to the PAS recovery condition there was a 10% and 22% decrease in FTI in the second and third trials, respectively. The PAS...
269

Predicting Cognitive Workload with Measures from Functional Near-Infrared Spectroscopy (fNIRS) and Heart Rate

Duany, John 01 August 2013 (has links)
The objective of this study was to assess low to high levels of Cognitive Workload by measuring heart rate and cortical blood flow in real-time. Four conditions were implemented into a within-subjects experimental design. Two conditions of difficulty and two conditions of trial order were used to illicit different levels of workload which will be analyzed with psychophysiological equipment. Functional Near-Infrared Spectroscopy (fNIRS) has become more prominent for measuring the blood oxygenation levels in the prefrontal cortex of individuals operating in hazardous work environments, students with learning disabilities, and in research for military training. This is due to the fNIR device being highly mobile, inexpensive, and able to produce a high-spatial resolution of the dorsolateral prefrontal cortex during executive functioning. Heart Rate will be measured by an Electrocardiogram, which will be used in concordance with fNIR oxygenation levels to predict if an individual is in a condition that produces low or high mental workload. Successfully utilizing heart rate and blood oxygenation data as predictors of cognitive workload may validate implementing multiple physiological devices together in real-time and may be a more accurate solution for preventing excessive workload.
270

Spectral Study of Asteroids and Laboratory Simulation of Asteroid Organics

Hargrove, Kelsey 01 January 2015 (has links)
We investigate the spectra of asteroids at near- and mid-infrared wavelengths. In 2010 and 2011 we reported the detection of 3 ?m and 3.2-3.6 ?m signatures on (24) Themis and (65) Cybele indicative of water-ice and complex organics [1] [2] [3]. We further probed other primitive asteroids in the Cybele dynamical group and Themis family, finding diversity in the shape of their 3 ?m [4] [5] [6] and 10 ?m spectral features [4]. These differences indicated mineralogical and compositional variations within these asteroid populations. Also in the mid-infrared region we studied a larger population of asteroids belonging to the Bus C, D, and S taxanomic classes to understand the relationship between any mineralogy and hydration inferred in the visible and near- infrared with the shape, strength, and slope of the 10 ?m emission. We have discovered that at least 3 of the main Bus taxanomic groups (Cs, Ds, and Ss as defined by their visible spectra) clearly cluster into 3 statistically distinct groups based on their 8-13 ?m spectra. Additionally we have attempted to simulate in a laboratory the possible organic compounds we have detected on two asteroids, using various mixtures containing aromatic and aliphatic hydrocarbons. We find that asteroid (24) Themis and (65) Cybele have ?CH2/?CH3 and NCH2/NCH3 ratios similar to our 3- methylpentane, propane, and hexane residues, suggesting that the organics on these asteroids may be short chained and/or highly branched. The ?CH2/?CH3 and NCH2/NCH3 for asteroid(24)Themis are most consistent with the DISM, and some carbonaceous chondrites. The band centers of the C-H stretch absorptions indicate that both asteroids may have aliphatic carriers chemically bonded to electronegative groups (i.e. aromatics), and some that are not. We also detect a 3.45 ?m feature in the spectra of both asteroids that is present in several dense molecular clouds. Our results suggest an interstellar origin for the organics on (24) Themis, and likely (65) Cybele. The differences in the organics of Themis and Cybele are likely related to variations in thermal processing, irradiation and/or formation region in the solar nebula.

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