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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.
11

Noninvasive blood pressure pulse detection and blood pressure determination

Sorvoja, H. (Hannu) 28 November 2006 (has links)
Abstract This thesis describes the development of pressure sensor arrays and a range of methods suitable for the long-term measurement of heart rate and blood pressure determination using a cuff and a pressure sensor array on the radial artery. This study also reviews the historical background of noninvasive blood pressure measurement methods, summarizes the accuracies achieved and explains the requirements for common national and international standards of accuracy. Two prototype series of pressure transducer arrays based on electro-mechanical film (EMFi) were designed and tested. By offering high (∼TΩ) resistance, EMFi is an excellent material for low-current long-term measurement applications. About 50 transducer arrays were built using different configurations and electrode materials to sense low-frequency pressure pulsations on the radial artery in the wrist. In addition to uniform quality, essential requirements included an adequate linear response in the desired temperature range. Transducer sensitivity was tested as a function of temperature in the range of 25–45 °C at varying static and alternating pressures. The average sensitivity of the EMFi used in the transducers proved adequate (∼2.2 mV/mmHg and ∼7 mV/mmHg for normal and high sensitive films) for the intended purpose. The thesis also evaluates blood pressure measurements by the electronic palpation method (EP) and compares the achieved accuracy to that of the oscillometric method (OSC) using average intra-arterial (IA) blood pressure as a reference. All of these three measurements were made simultaneously for each person. In one test group, measurements were conducted on healthy volunteers in sitting and supine position during increasing and decreasing cuff pressure. Another group, comprising elderly cardiac patients, was measured only in the supine position during cuff inflation. The results showed that the EP method was approximately as accurate as the OSC method with the healthy subjects and slightly more accurate with the cardiac patient group. The advantage of the EP method is that also the wave shape and velocity of arterial pressure pulses is available for further analysis, including the assessment of arterial stiffness.
12

Predicting Transit Times For Outbound Logistics

Brooke Renee Cochenour (8996768) 23 June 2020 (has links)
On-time delivery of supplies to industry is essential because delays can disrupt production schedules. The aim of the proposed application is to predict transit times for outbound logistics thereby allowing suppliers to plan for timely mitigation of risks during shipment planning. The predictive model consists of a classifier that is trained for each specific source-destination pair using historical shipment, weather, and social media data. The model estimates the transit times for future shipments using Support Vector Machine (SVM). These estimates were validated using four case study routes of varying distances in the United States. A predictive model is trained for each route. The results show that the contribution of each input feature to the predictive ability of the model varies for each route. The mean average error (MAE) values of the model vary for each route due to the availability of testing and training historical shipment data as well as the availability of weather and social media data. In addition, it was found that the inclusion of the historical traffic data provided by INRIX™ improves the accuracy of the model. Sample INRIX™ data was available for one of the routes. One of the main limitations of the proposed approach is the availability of historical shipment data and the quality of social media data. However, if the data is available, the proposed methodology can be applied to any supplier with high volume shipments in order to develop a predictive model for outbound transit time delays over any land route.
13

The effect of differentiation technique utilized in continuous noninvasive blood pressure measurement

Mueller, Jonathon W. 18 May 2006 (has links)
No description available.
14

Unveiling Causal Links, Temporal Patterns, and System-Level Dynamics of Freshwater Salinization Using Transit Time Distribution Theory

Bhide, Shantanu Vidyadhar 18 October 2023 (has links)
Inland freshwater salinity is rising worldwide and threatens the quality of our water resources, a phenomenon called the freshwater salinization syndrome (FSS). Simultaneously, the practice of indirect potable reuse (IPR) that augments critical water supplies with treated wastewater to enhance water security presents complexities in water quality management. This dissertation explores the complex interplay between FSS and IPR in the Occoquan Reservoir, an important drinking-water source in the Mid-Atlantic United States, within its diverse environmental, social and political contexts. Using extensive data collected over 25 years, this research quantifies contributions of multiple salinity sources to the rising concentration of sodium (a major ion associated with the FSS) in the reservoir and the finished drinking water. These sources encompass two rapidly urbanizing watersheds, a sophisticated water reclamation facility and the drinking water treatment utility. The novel application of unsteady transit time theory reveals that stream salinization can be linked to watershed salt sources using stream water age as a master variable and provides a real-time prediction model for sodium concentration in the reservoir. These results identify substantial opportunities to mitigate sodium pollution and help set the stage for stakeholder-driven bottom-up management by improving the predictability of system dynamics, enhancing knowledge of this social-ecological system and supporting the development of collective action rules. / Doctor of Philosophy / The global rise in freshwater salinity, termed as the freshwater salinization syndrome (FSS), poses a significant threat to water quality in our freshwater resources. The practice of indirect potable reuse (IPR), which involves reusing treated wastewater to supplement and secure our water supplies presents significant challenges in managing water quality. This dissertation delves into the intricate relationship between FSS and IPR, focusing on the Occoquan Reservoir-a vital drinking water source in the Mid-Atlantic United States-within its multifaceted environmental, social, and political contexts. This study uncovers the contributions of various sources of salinity to rising sodium ion concentrations (a key FSS-associated ion) in the reservoir and in finished drinking water. Sodium ions are contributed by road salts, chemicals used in water and wastewater treatment, commercial and industrial discharges, household products (e.g., laundry detergents) and human excretion. An innovative approach of examining the age of water in the stream and in the reservoir outflow enables us to trace origins of salinity within the watershed and predict the concentration of sodium ions in the reservoir, respectively. These findings reveal promising avenues for effectively addressing sodium pollution at this site. Furthermore, this research underscores the significance of convergence research, bringing diverse stakeholders together to develop collaborative strategies to manage freshwater salinization using a bottom-up approach.
15

Transit dosimetry in 192Ir high dose rate brachytherapy

Ade, Nicholas 02 December 2010 (has links)
Background and purpose: Historically HDR brachytherapy treatment planning systems ignore the transit dose in the computation of patient dose. However, the total radiation dose delivered during each treatment cycle is equal to the sum of the static dose and the transit dose and every HDR application therefore results in two radiation doses. Consequently, the absorbed dose to the target volume is more than the prescribed dose as computed during treatment planning. The aim of this study was to determine the magnitude of the transit dose component of two 192Ir HDR brachytherapy units and assess its dosimetric significance. Materials and Methods: Ionization chamber dosimetry systems (well-type and Farmertype ionization chambers) were used to measure the charge generated during the transit of the 192Ir source from a GammaMed and a Nucletron MicroSelectron HDR afterloader using single catheters of lengths 120 cm. Different source configurations were used for the measurements of integrated charge. Two analysis techniques were used for transit time determination: the multiple exposure technique and the graphical solution of zero exposure. The transit time was measured for the total transit of the radioactive source into (entry) and out of (exit) the catheters. Results: A maximum source transit time of 1.7 s was measured. The transit dose depends on the source activity, source configuration, number of treatment fractions, prescription dose and the type of remote afterloader used. It does not depend on the measurement technique, measurement distance or the analysis technique used for transit time determination. Conclusion: A finite transit time increases the radiation dose beyond that due to the programmed source dwell time alone. The significance of the transit dose would increase with a decrease in source dwell time or a higher activity source.
16

Experimental and clinical studies on the antiemetic effects of propofol

Hammas, Bengt January 2001 (has links)
<p>Postoperative nausea and vomiting (PONV) is still a clinical problem and its incidence is unacceptably high. After the introduction of propofol as an agent for induction and maintenance of anesthesia, it was reported that the incidence of PONV was lower. It was also proposed that propofol possesses antiemetic effects. Dopamine, serotonin and opioids may contribute to PONV. Therefore the purpose of these investigations was to evaluate if propofol has dopamine, serotonin or opioid antagonistic effects and if a subhypnotic infusion of propofol decreases the incidence of PONV. </p><p>Nausea and vomiting were induced in volunteers by a dopamine agonist, apomorphine, and by ipecacuanha which releases serotonin from the enterochromaffin cells in the gut. The effects of propofol on gastric emptying and orocecal transit time were evaluated in volunteers with the paracetamol method and by measuring the endtidal hydrogen concentration after ingestion of the trisaccharide raffinose. The effects of morphine on gastric emptying and gastric tone were studied in patients before surgery with the paracetamol method and with an electronic barostat, respectively. The effects of low dose propofol for prophylaxis of PONV were studied in 172 patients undergoing breast and abdominal surgery. Propofol prophylaxis was compared with a multidrug regimen consisting of dexamethasone and three antiemetic drugs, ondansetron, droperidol and metoclopramide. </p><p>Propofol did not abolish apomorphine-induced vomiting but reduced the number of retchings induced by ipecacuanha. Propofol sedation did not influence gastric emptying of liquids but it slightly prolonged orocecal transit time. Gastric relaxation induced by morphine was abolished by propofol but propofol did not abolish morphine-induced delay of gastric emptying. Propofol in a low dose infusion reduced the incidence of PONV but nausea and especially vomiting increased significantly after termination of the infusion. Pro- phylaxis with the multidrug regimen was very effective in preventing PONV. </p><p>These studies have shown that propofol does not have any dopamine antagonistic effect but may have a weak serotonin antagonistic effect. Propofol cannot abolish morphine-induced delay of gastric emptying. Low dose propofol infusion was effective in preventing PONV as long as the infusion was ongoing but after termination of the infusion nausea and especially vomiting substantially increased. The multidrug regimen (dexamethasone, ondansetron, droperidol, metoclopramide) was very effective in preventing PONV and can be recommended as prophylaxis in patient groups with a known high risk for PONV. </p>
17

Experimental and clinical studies on the antiemetic effects of propofol

Hammas, Bengt January 2001 (has links)
Postoperative nausea and vomiting (PONV) is still a clinical problem and its incidence is unacceptably high. After the introduction of propofol as an agent for induction and maintenance of anesthesia, it was reported that the incidence of PONV was lower. It was also proposed that propofol possesses antiemetic effects. Dopamine, serotonin and opioids may contribute to PONV. Therefore the purpose of these investigations was to evaluate if propofol has dopamine, serotonin or opioid antagonistic effects and if a subhypnotic infusion of propofol decreases the incidence of PONV. Nausea and vomiting were induced in volunteers by a dopamine agonist, apomorphine, and by ipecacuanha which releases serotonin from the enterochromaffin cells in the gut. The effects of propofol on gastric emptying and orocecal transit time were evaluated in volunteers with the paracetamol method and by measuring the endtidal hydrogen concentration after ingestion of the trisaccharide raffinose. The effects of morphine on gastric emptying and gastric tone were studied in patients before surgery with the paracetamol method and with an electronic barostat, respectively. The effects of low dose propofol for prophylaxis of PONV were studied in 172 patients undergoing breast and abdominal surgery. Propofol prophylaxis was compared with a multidrug regimen consisting of dexamethasone and three antiemetic drugs, ondansetron, droperidol and metoclopramide. Propofol did not abolish apomorphine-induced vomiting but reduced the number of retchings induced by ipecacuanha. Propofol sedation did not influence gastric emptying of liquids but it slightly prolonged orocecal transit time. Gastric relaxation induced by morphine was abolished by propofol but propofol did not abolish morphine-induced delay of gastric emptying. Propofol in a low dose infusion reduced the incidence of PONV but nausea and especially vomiting increased significantly after termination of the infusion. Pro- phylaxis with the multidrug regimen was very effective in preventing PONV. These studies have shown that propofol does not have any dopamine antagonistic effect but may have a weak serotonin antagonistic effect. Propofol cannot abolish morphine-induced delay of gastric emptying. Low dose propofol infusion was effective in preventing PONV as long as the infusion was ongoing but after termination of the infusion nausea and especially vomiting substantially increased. The multidrug regimen (dexamethasone, ondansetron, droperidol, metoclopramide) was very effective in preventing PONV and can be recommended as prophylaxis in patient groups with a known high risk for PONV.
18

Kvietrugių maistinės vertės tyrimai ir jų panaudojimas viščiukų broilerių mityboje / Triticale nutritional studies and their use in broiler diets

Valuckas, Julius 18 June 2014 (has links)
Darbo tikslas: ištirti kvietrugių maistinę vertę ir jų panaudojimo galimybes viščiukų broilerių mityboje. Darbo uždaviniai: ištirti kvietrugių maistinę vertę; ištirti kvietrugių įtaką viščiukų broilerių virškinimo procesams. Rezultatai: išanalizavus 11 kvietrugių veislių nustatytas vidutinis žalių baltymų kiekis – 11,99 proc., žalių riebalų – 0,83 proc., žalių pelenų – 1,31 proc., vidutinis krakmolo kiekis – 69,69 proc., kalcio – 0,07 proc., fosforo – 0,303 proc. Pagrindinių aminorūgščių, lizino, metionino, treonino ir triptofano vidutiniai kiekiai atitinkamai nustatyti – 0,36 proc., 0,17 proc., 0,3 proc., 0,13 proc. Naudojant viščiukų lesinimui multifunkcinį fermentą bei kvietrugių veislę Tulus žarnyno svoris, ilgis bei aklosios žarnos ilgis mažėjo 4 – 6 proc., o naudojant veislę Lego - esminių pokyčių nenustatyta. Naudojant fermentą bei kvietrugių veisles Lego ir Tulus širdies svoris padidėjo atitinkamai 8 ir 10 proc., lesinant minėtas kvietrugių veisles ir fermentą kepenų svoris padidėjo atitinkamai 10 ir 8 proc. Naudojant viščiukų lesinimui multifunkcinį fermentinį priedą virškinamosios masės klampumas viščiukų broilerių aklojoje žarnoje padidėjo 11 – 23 proc. / Purpose of work: investigate the nutritional value of triticale as well as the use of it as a feed to broiler chicken. The tasks of work: investigation of triticale nutritional value; investigation of triticale influence to digestive processes of broiler chicken. Results: an analysis of 11 triticale varieties has shown that the average crude protein content is 11.99 percent, crude fat 0.83 percent, green ash 1.31 percent, starch 69.69 percent, calcium - 0.07 percent, phosphorus - 0.303 percent. The average amount of basic amino acids, lysine, methionine and tryptophan in triticale are as follows: 0.36 percent, 0.17 percent, 0.3 percent, 0.13 percent. The research has shown that by using multifunctional enzymes and triticale variety Tulus intestinal weight, length and caecum length decreased by 4-6 percent; whereas the use of triticale variety Lego has resulted in no major differences. The use of both varieties Lego and Tulus resulted in increase of heart weight by 8-10 percent and increase in liver weight by 10 for Lego and 8 percent for Tulus variety. The use of multifunctional enzyme has also resulted in viscosity of digestible mass in an increase in broiler caecum by 11-23 percent.
19

Temporal and spatial structures of denitrification in crystalline aquifers / Dénitrification dans les aquifères cristallins : variations temporelles et spatiales

Kolbe, Tamara 04 July 2017 (has links)
La contamination des aquifères de proche subsurface par les intrants d'origine agricole (nitrates) est un problème mondial.L'utilisation excessive d'engrais depuis plusieurs décennies a impacté la qualité des masses d'eau souterraines et soulève des enjeux pour la santé humaine comme pour celle des écosystèmes. Les nitrates dans les aquifères peuvent être réduits en diazote gazeux par l'activité microbienne hétérotrophique (la biomasse microbienne obtenant l'énergie nécessaire à ce processus via le carbone organique issu de la surface) et/ou par l'activité autotrophique (la biomasse microbienne obtenant cette fois ci son énergie depuis une source proche, lithologique). Les taux de dénitrification sont très variables spatialement, et sont régulés par l'interaction entre la structure des flux d'eau souterrains avec l'activité biogéochimique. Localiser l'activité biogéochimique dans les aquifères est difficilement réalisable à l'échelle des bassins versants, mais paraît crucial pour la gestion des masses d'eau souterraines. Bien que les processus de l'activité microbienne ne puissent pas être entièrement résolus à l'échelle locale, ce manuscrit de thèse propose une caractérisation des taux de dénitrification à l'échelle du bassin versant, basée sur l'analyse de données et sur une approche de modélisation intégrée. Cette thèse propose d'utiliser de manière extensive des traceurs conservatifs et réactifs associés aux flux d'eau souterraine et des modèles de transport afin d'identifier les contrôles géologiques et biogéochimiques sur les capacités de dénitrification dans les aquifères. Cette méthodologie a été appliquée à un aquifère libre cristallin de 76 km² situé en Bretagne. A partir des concentrations en CFC-12, O2, NO3- et N2 dissous mesurées dans 16 puits, il a été possible de reconstituer les chroniques d'apports de nitrate dans la zone saturée et de définir les variations spatio-temporelles de la dénitrification. Il est prouvé ici que la dénitrification est en premier lieu contrôlée par la position des donneurs d'électron. Ce travail propose un cadre d'interprétation général sur la base de l'utilisation combinée et complémentaire des traceurs et sur la modélisation semi-explicite pour estimer à l'échelle régionale les capacités de dénitrification et les stocks de nitrates dans les aquifères. / Unconfined shallow aquifers in agricultural areas are contaminated by nitrates worldwide. Excessive fertilization over the last decades has affected groundwater quality as well as human and ecosystem wellbeing. Nitrate in groundwater can be microbially reduced to dinitrogen gas by heterotrophic (microbes obtaining their energy from surface-derived organic carbon) and autotrophic (microbes obtaining their energy from a lithological source) processes. However, denitrification rates are highly spatially variable, following involved interactions between groundwater flow structures and biogeochemical activity. The location of biogeochemical activity in the aquifer is difficult to access at the catchment scale, but of vast importance to gain predictive capabilities for groundwater management. Even though microbial processes cannot be resolved at the local scale, this dissertation proposes a catchment scale characterization of denitrification rates based on an integrated model- and data-driven approach. The dissertation proposes an extensive use of conservative and reactive tracers combined with groundwater flow and transport models to identify the geological and biogeochemical controls on aquifer denitrification capacities. The methodology is applied to a crystalline unconfined aquifer of 76 km2 size in Brittany, France. Based on CFC-12, O2, NO3-, and dissolved N2 concentrations measured in 16 wells, it is possible to reconstruct historical nitrate inputs to the saturated zone and to define spatiotemporal denitrification activity. It is shown that denitrification is primarily controlled by the location of electron donors. The dissertation proposes a general interpretation framework based on tracer information combined with complementary semi-explicit lumped parameter models to assess regional denitrification capacities and nitrate legacy.
20

A Modeling Approach for Coefficient-Free Oscillometric Blood Pressure Estimation

Forouzanfar, Mohamad 27 June 2014 (has links)
Oscillometry is the most common measurement method used in automatic blood pressure (BP) monitors. However, most of the oscillometric algorithms are without physiological and theoretical foundation, and rely on empirically derived coefficients for systolic and diastolic pressure evaluation which affects the reliability of the technique. In this thesis, the oscillometric BP estimation problem is addressed using a comprehensive modeling approach, based on which coefficient-free estimation of BP becomes possible. A feature-based neural network approach is developed to find an implicit relationship between BP and the oscillometric waveform (OMW). The modeling approach is then extended by developing a mathematical model for the OMW as a function of the arterial blood pressure, cuff pressure, and cuff-arm-artery system parameters. Based on the developed model, the explicit relationship between the OMW and the systolic and diastolic pressures is found and a new coefficient-free oscillometric BP estimation method using the trust region reflective algorithm is proposed. In order to improve the reliability of BP estimates, the electrocardiogram signal is recorded simultaneously with the OMW, as another independent source of information. The electrocardiogram signal is used to identify the true oscillometric pulses and calculate the pulse transit time (PTT). By combining our developed model of oscillomtery with an existing model of the pulse wave velocity, a new mathematical model is derived for the PTT during the cuff deflation. The derived model is incorporated to study the PTT-cuff pressure dependence, based on which a new coefficient-free BP estimation method is proposed. In order to obtain accurate and robust estimates of BP, the proposed model-based BP estimation method sare fused by computing the weighted arithmetic mean of their estimates. With fusion of the proposed methods, it is observed that the mean absolute error (MAE) in estimation of systolic and diastolic pressures is 4.40 and 3.00 mmHg, respectively, relative to the Food and Drug Administration-approved Omron monitor. In addition, the proposed feature-based neural network was compared with auscultatory measurements by trained observers giving MAE of 6.28 and 5.73 mmHg in estimation of systolic and diastolic pressures, respectively. The proposed models thus show promise toward developing robust BP estimation methods.

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