• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 21
  • 14
  • 6
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 60
  • 16
  • 10
  • 9
  • 9
  • 8
  • 7
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 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

Vliv teploty, tlaku a vlhkosti spalovacího vzduchu na výkonové parametry motoru

Lužný, Jan January 2009 (has links)
No description available.
2

Platelet Activation and Inhibition in Connection with Vascular Stents

Christensen, Kjeld January 2007 (has links)
<p>This thesis describes the Chandler loop, which makes it possible to conduct studies in vitro of molecular and cellular interactions between whole blood and stents. It was possible to monitor activation and inhibition of the cascades systems, leukocytes and platelets by combining different platelet inhibitors and heparin coating of stents. The clinical study was performed on patients with ACS undergoing PCI and stent implantation. In this study platelet activation markers P-selectin, and αIIb/β3 as well as inflammatory markers were followed from baseline during the first 48 hours post-PCI. The same parameters were evaluated in healthy controls for comparison at baseline. </p><p>In vitro: The activation of blood in the Chandler loops were more pronounced for unmodified stent grafts than for partially heparin coated stent grafts. Heparin coated stent grafts dreated the same activation as the loops alone. This indicated that the Chandler loop system was a feasible tool for evaluation of blood compability of stents. </p><p>Heparin coating of stents significantly reduced TAT, CD11b and platelet activation. The combination of a heparin coated stent and abciximab reduced TAT and contact activation, as compared to abciximab or heparin coating alone. </p><p>Heparin coating of stents in combination with AR-C69931MX resulted in a significant reduction in TAT and preservation of the platelet count but had no effect on contact activation. </p><p>Clinical study: Abciximab resulted in an almost total inhibition of fibrinogen binding to platelets and persisted throughout the observation period. Clopidogrel effectscould be observed at four hours but was more pronounced at 24 hours. </p><p>P-selectin expression did not differ over time between groups, indicating that platelet activation with α-granule secretion was not affected by abciximab treatment. </p><p>The hs-CRP, C3a and sC5b-9 levels increased 24 to 48 hours after PCI in patients with ACS. FXIIa-C1inh was reduced in ACS patients receiving abciximab as compared to controls. The elevated bFGF levels at baseline returned to the levels observed in controls four hours after PCI and stent implantation, whereas an increase in VEGF was observed 24 hours post-PCI.</p>
3

Platelet Activation and Inhibition in Connection with Vascular Stents

Christensen, Kjeld January 2007 (has links)
This thesis describes the Chandler loop, which makes it possible to conduct studies in vitro of molecular and cellular interactions between whole blood and stents. It was possible to monitor activation and inhibition of the cascades systems, leukocytes and platelets by combining different platelet inhibitors and heparin coating of stents. The clinical study was performed on patients with ACS undergoing PCI and stent implantation. In this study platelet activation markers P-selectin, and αIIb/β3 as well as inflammatory markers were followed from baseline during the first 48 hours post-PCI. The same parameters were evaluated in healthy controls for comparison at baseline. In vitro: The activation of blood in the Chandler loops were more pronounced for unmodified stent grafts than for partially heparin coated stent grafts. Heparin coated stent grafts dreated the same activation as the loops alone. This indicated that the Chandler loop system was a feasible tool for evaluation of blood compability of stents. Heparin coating of stents significantly reduced TAT, CD11b and platelet activation. The combination of a heparin coated stent and abciximab reduced TAT and contact activation, as compared to abciximab or heparin coating alone. Heparin coating of stents in combination with AR-C69931MX resulted in a significant reduction in TAT and preservation of the platelet count but had no effect on contact activation. Clinical study: Abciximab resulted in an almost total inhibition of fibrinogen binding to platelets and persisted throughout the observation period. Clopidogrel effectscould be observed at four hours but was more pronounced at 24 hours. P-selectin expression did not differ over time between groups, indicating that platelet activation with α-granule secretion was not affected by abciximab treatment. The hs-CRP, C3a and sC5b-9 levels increased 24 to 48 hours after PCI in patients with ACS. FXIIa-C1inh was reduced in ACS patients receiving abciximab as compared to controls. The elevated bFGF levels at baseline returned to the levels observed in controls four hours after PCI and stent implantation, whereas an increase in VEGF was observed 24 hours post-PCI.
4

小規模SNSのモデル化と活性化シミュレーション(<特集>ネットワークソフトウェア論文)

鳥海, 不二夫, 石田, 健, 石井, 健一郎 01 April 2008 (has links)
No description available.
5

Controls Algorithm For A Satellite Using Earth's Magnetic Field: Orbit Maneuvers And Attitude Positioning

Ganesh, Karthik 01 January 2007 (has links)
This document describes the design, analysis of Orbit Maneuvers and Attitude Control for NanoSat class satellites, which uses an electro-magnetic force controller which was proposed by the Florida Space Institute (FSI). Orbit Maneuvering and the Attitude Control System (ACS) play a very important role for the success of this mission, as that can allow making the satellite go to the desired orbit as well do the sun pointing of the solar arrays with su¢ cient accuracy to achieve desired power levels. The primary mission would be to attain attitude stabilization using the torque from the coils. This is also used for pointing at the direction of the sun, for achieving desired power levels. The secondary mission would be to use the force of the magnetic field and utilize that for orbit maneuvering, and attain the desired trajectory. This thesis gives a presentation of this detailed analysis with a simulation using Matlab/Simulink. Mathematical model of the actuators and sensors used for this satellite are designed, so that the simulation gives us results very near to the actual ones.Health Monitoring is also one of the main issues addressed in this work. This simulation helps us in understanding the mission as well as the requirements very well, and helps us know all the shortcomings. The FUNSAT satellite is modeled as an example in Simulink together with a Kalman filter for attitude estimation based on all sensor measurements. The theory behind this, and extending the Kalman filter, is also presented.
6

New targetry possibilities from the TR-24

Zyuzin, A., Sader, J., Jenei, E., Tremblay, S., Thibault, P., Guerin, B. 19 May 2015 (has links) (PDF)
Introduction The TR-24 is relatively new to the cyclotron market and its advantages over lower energy PET cyclotrons have not yet been fully realized. A new high current [18F] fluoride production target that takes advantage of the higher energy and current afforded by the TR-24 has been developed. Material and Methods The TR-24 cyclotron presents challenges of producing conventional PET isotopes even with its variable energy capability (18–25 MeV). Simultaneous irradiation of two targets that require different proton energies is possible only using beam energy degrader. Due to the relatively wide energy window, the degrader design is not trivial, especially for the high current operation. For example, reduction of beam energy from 24 to 18 MeV would require the use of an approximately 1.5 mm thick aluminum degrader. At 100 μA this degrader would have to be capable of dissipating 700 W of beam power, which would be challenging to achieve with no cooling or using a conventional helium cooling window. However, cooling water used as a beam energy degrader can dissipate several kilowatts of beam energy and provide additional cooling for target material and window foils. FIGURE 1 demonstrates the concept of the water cooled target window. A standard 18F- water target with a 2.5 mL fill volume and a 30 degree beam incident angle was modified to accept the new water window. A 1 mm thick region of circulating cooling water was inserted between the vacuum and the product foil. The combined beam energy degradation caused by the vacuum foil (0.00012“ Havar), the cooling water (1 mm) and the target foil (0.00012“ Havar) was approximately 7 MeV for a 24 MeV incident proton energy. The target was installed on a target selector mounted directly on the TR-24 cyclotron. No additional beam focusing or steering devices were used to defocus or correct beam shape. A small recirculation water system was setup to supply cooling water for the degrader. A mixed bed ion exchange column was installed on the return line to trap N-13 and radioactive metal ions that could possibly be etched from the Havar foils. The water in the degrader was continually circulated in a closed loop providing cooling to the vacuum and target foils. An 800mL/min water flow through the degrader was generated by a low pressure water pump. Results Several tests were performed with O-16 water to establish current – pressure curve and to determine “burn through” current (FIGURE 2). Conclusion Initial tests demonstrated that the new F-18 target with a 1 mm water degrader is capable of accepting power levels in excess of 3.6 kW, operating at 150 μA. More testing is under way, including testing with H218O to determine the F-18 production capacity of this target. We will look into adapting this concept to all ACSI PET targets, including the high current F-18 produc-tion target which can potentially reach an operational current of 200 μA.
7

The Acute Coronary Syndrome Experience among Native American Adults in Northern Arizona

Brice, Norria Marie January 2016 (has links)
Diseases of the heart have been the number one cause of death in the Native American population for decades and is an adverse health disparity for this population. Heart disease mortality rates are higher in Native Americans than in the U.S. population (American Heart Association, 2015; Veazie et al., 2014). The purpose of this Doctor of Nursing Practice (DNP) project is to describe the acute coronary syndrome (ACS) experience among Native American adults who reside in northern Arizona and diagnosed with an acute myocardial infarction .A qualitative dominant mixed methods design (QUAL→quan) was used to describe the ACS symptom experience among this population. Data was collected from a convenience sample of nine Native American men residing on the Navajo and Hopi reservations in northern Arizona diagnosed with an acute myocardial infarction. The qualitative portion of this study consisted of a semi-structured interview and the quantitative portion consisted of the completion of a demographic questionnaire and the McSweeney Acute and Prodromal Myocardial Infarction Symptom Survey. Qualitative description were used to analyze the data and develop codes, subcategories, categories and themes. Descriptive statistics were used to analyze the data from the demographic questionnaire and MAPMISS results. The findings in this study revealed the average age of the first heart attack for these participants was 58 years. The average time from symptom onset to hospital presentation was 7.4 hours. A common prodromal symptom was very tired/unusual fatigue. Common acute symptoms were chest pain, shortness of breath, gastrointestinal symptoms and diaphoresis. Neck/throat, generalized chest, and top of shoulders were most frequently reported areas of acute pain or discomfort. Influences to not seeking treatment included ignoring symptoms or thinking symptoms would go away. Influences to seeking treatment included worsening or non-resolution of symptoms. Accessing health care was difficult for almost all participants and contributed to treatment delay. Findings from this study gave new insight on ACS symptoms and the ACS experience of Native American men, reinforced current knowledge of the health disparities that exist in this population, and will assist in the development of culturally-sensitive, community-based education programs directed toward the Native American population.
8

How might we create a more realistic ECG Training?

Siebert, Jost January 2016 (has links)
Electrocardiography (ECG or EKG) is the process of recording the electrical activity of the heart over a period of time using electrodes placed on a patient’s body. These electrodes detect the tiny electrical changes on the skin that arise from the heart muscle depolarizing during each heartbeat. [1] It is necessary for the diagnosis and prompt initiation of therapy in patients with acute coronary syndromes (ACS) and is the most accurate means of diagnosing conduction disturbances and arrhythmias. [2]ECG is an irreplaceable diagnostic method in clinical practice. It offers great diagnostic value at minimal costs while being a relatively quick, painless and noninvasive process. The quality of the resulting graph is depending on the accurate placement of the electrodes on the patients' body and that the patient lies absolutely still to avoid any muscle contractions which may lead to distortions of the graph.The interpretation of ECGs is a highly complex topic which requires lots of training and experience. Although there has been plenty of research on the topic of automated interpretation and pattern recognition of ECGs by computer algorithms and neural networks, a reliable interpretation of complex ECGs cannot be guaranteed as of today. While the trend seems to favor automated ECG interpretation, a clear prediction when these technologies have saturated the market cannot be given. One reason for this, similar to autonomous vehicles, is the issue of where liability can be found when an incorrect diagnosis leads to harming of a patient. For the foreseeable future we will most likely rely on the skill and experience of humans to interpret ECGs. [1] https://en.wikipedia.org/wiki/Electrocardiography [2] The British Journal of Primary Care Nursing: Taking an ECG: Getting the best possible recording
9

The bioinorganic chemistry of N2S2 metal complexes: reactivity and ligating ability

Golden, Melissa Lynn 29 August 2005 (has links)
[N,N??-bis-(mercaptoethyl)-1,5-diazacyclooctanato]NiII, Ni-1, is known to undergo metallation reactions with numerous metals. [N,N??-bis-(mercaptoethyl)-1,5-diazacycloheptanato]NiII, (bme-dach)Ni or Ni-1??, differs from Ni-1 by one less carbon in its diazacycle backbone ring producing subtle differences in N2S2Ni geometry. Metallation of Ni-1?? with PdCl2, Pd(NO3)2, and NiBr2 produced three structural forms: Ni2Pd basket, Ni4Pd2 C4-paddlewheel, and Ni3 slant chair. In attempts to provide a rationale for the heterogeneity in the active site of Acetyl coA Synthase, metal ion capture studies of Ni-1 in methanol found a qualitative ranking of metal ion preference: Zn2+ < Ni2+ < Cu+. Formation constants for metal ion capture of Ni-1?? in water were determined for Pb2+, Ni2+, Zn2+, Cu+, and Ag+. A quantitative estimate places copper some 15 orders of magnitude above nickel or zinc in binding affinity. Sulfur dioxide uptake by Ni-1?? is characterized by significant color change, improved adduct solubility, and reversible binding of two equivalents of SO2. These combined properties establish Ni-1?? as a suitable model for gas uptake at nickel thiolate sites and as a possibly useful chemical sensor for this poisonous gas. Comparisons of molecular structures, ν(SO) stretching frequencies, and thermal gravimetric analyses are made to reported adducts including the diazacyclooctane derivative, Ni-1·2SO2. Visual SO2 detection limits of Ni-1 and Ni-1?? are established at 25 ppm and 100 ppm, respectively. Structural studies of products resulting from reaction at the nucleophilic S-sites of (bme-dach)Ni and [(bme-dach)Zn]2 included acetyl chloride and sodium iodoacetate as electrophiles are shown. The acetyl group is a natural electrophile important to the citric acid cycle. Acetylation of (bme-dach)Ni produces a five coordinate, paramagnetic species. Iodoacetate is a cysteine modification agent known to inhibit enzymatic activity. The reaction of (bme-dach)Ni and sodium iodoacetate yields a blue, six coordinate nickel complex in a N2S2O2 donor environment. The bismercaptodiazacycloheptane ligand binds lead(II) forming an unprecedented structural form of N2S2M dimers, in which Pb2+ is largely bound to sulfur in a highly distorted trigonal geometry. Its unusual structure is described in comparison to other derivatives of the bme-daco ligand. The synthesis and structural characterization of square pyramidal (bme-dach)GaCl are also given and compared to the analogous (bme-daco)GaCl.
10

The bioinorganic chemistry of N2S2 metal complexes: reactivity and ligating ability

Golden, Melissa Lynn 29 August 2005 (has links)
[N,N??-bis-(mercaptoethyl)-1,5-diazacyclooctanato]NiII, Ni-1, is known to undergo metallation reactions with numerous metals. [N,N??-bis-(mercaptoethyl)-1,5-diazacycloheptanato]NiII, (bme-dach)Ni or Ni-1??, differs from Ni-1 by one less carbon in its diazacycle backbone ring producing subtle differences in N2S2Ni geometry. Metallation of Ni-1?? with PdCl2, Pd(NO3)2, and NiBr2 produced three structural forms: Ni2Pd basket, Ni4Pd2 C4-paddlewheel, and Ni3 slant chair. In attempts to provide a rationale for the heterogeneity in the active site of Acetyl coA Synthase, metal ion capture studies of Ni-1 in methanol found a qualitative ranking of metal ion preference: Zn2+ < Ni2+ < Cu+. Formation constants for metal ion capture of Ni-1?? in water were determined for Pb2+, Ni2+, Zn2+, Cu+, and Ag+. A quantitative estimate places copper some 15 orders of magnitude above nickel or zinc in binding affinity. Sulfur dioxide uptake by Ni-1?? is characterized by significant color change, improved adduct solubility, and reversible binding of two equivalents of SO2. These combined properties establish Ni-1?? as a suitable model for gas uptake at nickel thiolate sites and as a possibly useful chemical sensor for this poisonous gas. Comparisons of molecular structures,&#61472; &#957;(SO) stretching frequencies, and thermal gravimetric analyses are made to reported adducts including the diazacyclooctane derivative, Ni-1&#903;2SO2. Visual SO2 detection limits of Ni-1 and Ni-1?? are established at 25 ppm and 100 ppm, respectively. Structural studies of products resulting from reaction at the nucleophilic S-sites of (bme-dach)Ni and [(bme-dach)Zn]2 included acetyl chloride and sodium iodoacetate as electrophiles are shown. The acetyl group is a natural electrophile important to the citric acid cycle. Acetylation of (bme-dach)Ni produces a five coordinate, paramagnetic species. Iodoacetate is a cysteine modification agent known to inhibit enzymatic activity. The reaction of (bme-dach)Ni and sodium iodoacetate yields a blue, six coordinate nickel complex in a N2S2O2 donor environment. The bismercaptodiazacycloheptane ligand binds lead(II) forming an unprecedented structural form of N2S2M dimers, in which Pb2+ is largely bound to sulfur in a highly distorted trigonal geometry. Its unusual structure is described in comparison to other derivatives of the bme-daco ligand. The synthesis and structural characterization of square pyramidal (bme-dach)GaCl are also given and compared to the analogous (bme-daco)GaCl.

Page generated in 0.0387 seconds