| 1. |
- Dreilich, Martin, 1970-
(författare)
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Predictive Factors in Esophageal Carcinoma
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Esophageal carcinoma is a malignancy with a poor prognosis and is the sixth cause of cancer related death worldwide. In Sweden approximately 400 new cases are diagnosed every year. The aim of this present thesis was to investigate predictive factors for esophageal carcinoma patients.126 esophageal carcinoma patients admitted to the department of Oncology at the University Hospital in Uppsala between 1990-2000 were investigated with focus on known and potential prognostic factors. Performance status and stage of the disease were the only independent prognostic factors (p-values <0.001). Angiogenic factors VEGF and bFGF were correlated to platelet and leukocyte counts and VEGF was correlated to tumor volume (p=0.04) whereas bFGF was not (p=0.08) in pre-treatment serum samples from 42 esophageal carcinoma patients. The use of the angiogenic factors as prognostic factors, prior to therapy in patients with esophageal carcinoma, according to the results from the present study, seems limited. HER-2 overexpression was seen in 17% of 97 investigated esophageal tumor samples. In squamous cell carcinoma patients, HER-2 overexpression correlated with poorer survival (p=0.035), whereas in adenocarcinoma patients, HER-2 status did not. HER-2 overexpression seems to be associated with poorer survival in esophageal carcinomas, especially in patients with squamous cell esophageal carcinoma. Telomerase activity was detected in all esophageal cell lines, with a broad range of activity levels. No correlation was found between telomerase activity levels and sensitivity to investigated cytotoxic drugs. We therefore conclude that basal telomerase activity level is not a key determinant of sensitivity to standard cytotoxic drugs in esophageal carcinoma cell lines. The virus HPV-16 was detected in 16 % of the patients; no other type HPV was detected. HPV-16 infection had no significant effect on survival (p=0.72). Our results did not show that HPV-16 increases survival or improve therapy response in patients with esophageal carcinoma.
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| 2. |
- Jason, Johan, et al.
(författare)
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Modulation function study of coupling based intensity modulated fiber-optic sensors
- 2006
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Ingår i: Technical Digest: SOFM 2006. - Washington, DC : NIST. ; , s. 6-9
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The modulation function for fiber-optic sensors based on coupling between fiber ends is studied for different fiber types and fiber configurations, including multiple fiber passes. Sensitivity aspects are evaluated experimentally and theoretically. It is shown that multiple passes in reality do not result in a significant sensitivity increase due to coupling losses related to fiber alignment and reflection loss.
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| 3. |
- Jason, Johan, et al.
(författare)
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Monte Carlo Simulation of the Performance of a Fiber-Optic Position Sensor
- 2006
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Ingår i: 18th International Optical Fiber Sensors Conference Technical Digest. - Washington, DC : Optical Society of America. - 1557528179 ; , s. TuE48-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A numerical model for evaluation of a position sensor based on a single- to multicore fiber coupling and a real-time processing CMOS camera chip is presented, allowing design of sub-µm resolution, high dynamic range sensors.
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| 4. |
- Kawati, Rafael, 1967-
(författare)
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Evaluation of Respiratory Mechanics by Flow Signal Analysis : With Emphasis on Detecting Partial Endotracheal Tube Obstruction During Mechanical Ventilation
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Evaluating respiratory mechanics during dynamic conditions without interrupting ongoing ventilation and flow, adds to the information obtained from the mechanics derived from static (= no flow) conditions, i.e., the flow signal has the potential to provide information on the properties of the respiratory system (including the tubing system). Hence monitoring the changes in the flow signal during ongoing mechanical ventilation would give information about the dynamic mechanics of the respiratory system. Any change in the mechanics of the respiratory system including the endotracheal tube (ETT) and the ventilatory circuit would affect the shape of the flow signal. Knowledge of the airway pressure distal to the ETT at the carina level (= tracheal pressure) is required for calculating the extra resistive load exerted by the endotracheal tube in order to compensate for it. In a porcine model, the flow signal was used to non-invasively calculate tracheal pressure. There was good agreement between calculated and measured tracheal pressure with different modes of ventilation. However, calculation of tracheal pressure assumes that the inner diameter of the ETT is known, and this assumption is not met if the inner diameter is narrowed by secretions. Flow that passes a narrowed tube is decelerated and this is most pronounced with the high flow of early expiration, yielding a typical time constant over expiratory volume pattern that is easy to recognize during mechanical ventilation. This pattern reliably detected partial endotracheal obstruction during volume and pressure controlled mechanical ventilation. A change in compliance of the respiratory system modifies the elastic recoil and this also affects the rate of the expiratory flow and the shape of its signal. In a porcine model, lung volume gains on the flow signal generated by the heartbeats (cardiogenic oscillations) provided information about the compliance of the respiratory system during ongoing mechanical ventilationIn conclusion analyzing the flow signal during ongoing ventilation can be a cheap, non-invasive and reliable tool to monitor the elastic and resistive properties of the respiratory system including the endotracheal tube.
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| 5. |
- Larsson, Anders
(författare)
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High frequency distortion in power grids due to electronic equipment
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Power quality is a subject that has received a lot of attention during the last 10 to 20 years, both in industry and in academia. Power quality concerns interaction between the power grid and its customers and between the power grid and equipment connected to it, reflected in voltages and currents. Research and other developments in this area have to a great extent concentrated on relatively slow and low-frequency phenomena, with the main emphasis being on voltage dips (reductions in voltage magnitude with duration between about 50 ms and several seconds) and low-frequency harmonics (waveform distortion by frequency components up to about 2 kHz). These phenomena are reasonably well understood. For higher-frequency phenomena there is no such general understanding. There are a number of reasons for looking closer into this frequency range, including increased distortion by energy-efficient equipment, interference with equipment such as that used for communications, reduced service life of equipment, the availability of measurement and analysis tools, and pure scientific curiosity. This licentiate thesis addresses voltage and current distortion in low- voltage networks in the frequency range between 2 kHz and 1 MHz. The report starts with a general overview of power quality and power-quality disturbances. This part is mainly a review of existing knowledge. The report continues with a philosophical discussion of measurement and analysis of power-quality disturbances. The objectiveness of the analysis methods is especially addressed. The importance of understanding the limitations posed by measurement standards and commonly used analysis methods is emphasized. The choice of measurement and analysis tool has the potential to influence the conclusions drawn from a study. Different analysis and presentation tools are discussed for disturbances in the frequency band of interest. Where possible, a range of methods should be used. Next to the commonly used time- and frequency-domain presentations, the spectrogram or time-frequency-domain is introduced as a useful tool. The measurement technology used for obtaining sampled voltage and current waveforms is discussed. Measurements have been performed on the current drawn by individual devices and by groups of devices. These measurements have been performed mainly in a controlled laboratory environment. Voltage measurements have mainly been performed at a number of locations in the field. Both current and voltage measurements are described in detail in this report, together with the measurement results. The main contribution of this licentiate report is in the systematic analysis of disturbances in the frequency range between 2 kHz and 1 MHz. The spectrogram has proven a suitable tool for analyzing and visualizing these disturbances. Further knowledge is obtained on the disturbances arising from fluorescent lamps with high-frequency ballasts. Contrary to conventional knowledge, the main concern is in the so-called zero-crossing distortion. The level of this distortion component demonstrates a linear increase with the number of devices.
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| 6. |
- Lindblom, Adam, 1973-
(författare)
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Inductive Pulse Generation
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pulsed power generators are a key component in compact systems for generation of high-power microwaves (HPM). HPM generation by virtual cathode devices such as Vircators put high demands on the source. The rise time and the pulse length of the source voltage are two key issues in the generation of HPM radiation. This thesis describes the construction and tests of several inductive high power pulse generators. The pulse generators were designed with the intent to deliver a pulse with fast rise time and rectangular voltage. Therefore, the pulse generators are all based on discharges of transmission lines. The transmission lines used in the pulse generators are modern high voltage cables normally used in power transmission. All tested pulse generators have step up transformers as intermediate magnetic energy storage. Further, the pulse generators have contributed to the knowledge of compact designs. Closing switches is another important device in pulse generator architectures. In general, high power switching involving large currents and high voltages requires the use of robust switches. The switches used in the pulse generators of this thesis are of gas and liquid type.
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| 7. |
- Lipcsey, Miklós, et al.
(författare)
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Inflammatory, coagulatory and circulatory responses to logarithmic increases in the endotoxin dose in the anaesthetised pig
- 2006
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Ingår i: Journal of Endotoxin Research. - : SAGE Publications. - 0968-0519 .- 1743-2839. ; 12:2, s. 99-112
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Although porcine intravenous endotoxin shock models are widely employed in experimental sepsis, endotoxin dose-effect studies are scarce. Our primary aim was to establish the dose response to increasing endotoxin doses in inflammatory, coagulatory and haemodynamic effect variables, as well as to determine the optimal time point for assessment in a pig model. A secondary aim was to study pathophysiological covariations between the different responses. Twenty anaesthetised piglets received endotoxin intravenously in doses of 0.063 (n = 3), 0.25 (n = 3), 1.0 (n = 3), 4.0 (n = 3), 8 (n = 3) and 16 microg/kg/h (n = 2). In addition, non-endotoxin piglets constituted a control group (n = 3). Physiological variables were registered and blood samples analysed for TNF-alpha, IL-6, leukocyte, platelet and haemoglobin concentrations hourly for 6 h. Increases in the endotoxin dose induced significant log-log cytokine responses as well as log-linear leukocyte and platelet responses. Significant log-linear responses were observed for circulatory parameters, plasma leakage, hypoperfusion and pulmonary compliance. Significant covariations in the responses were noted. In conclusion, there were log-log or log-linear responses to endotoxin suggesting a greater effect of a given dose at lower pre-existing endotoxin concentrations and lower doses of < or = 1 microg/kg/h may be of advantage in experiments designed to study potential anti-endotoxin effects of experimental drugs or measures.
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| 8. |
- Lipcsey, Miklós, 1975-
(författare)
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Pathophysiological, Inflammatory and Haemostatic Responses to Various Endotoxaemic Patterns : An Experimental Study in the Pig
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Septic shock is frequently seen in intensive care units and is associated with significant mortality. Endotoxin – a major mediator of the pathophysiologic responses – is released during lysis of Gram-negative bacteria. These responses can be mimicked in the endotoxaemic pig. This thesis focuses on the following topics: the inflammatory and pathophysiological responses to various endotoxin doses and infusion patterns; covariations between endotoxin induced inflammatory and pathophysiological responses; whether the biological effects of endotoxin can be modulated by clopidogrel and whether tobramycin or ceftazidime reduce plasma cytokine levels. Endotoxin induced linear log-log cytokine and F2-isoprostane responses. Leukocyte and platelet responses, pulmonary compliance, circulatory variables as well as indicators of plasma leakage and hypoperfusion exhibited log-linear responses to the endotoxin dose. Biological responses to endotoxaemia such as inflammation, hypotension, hypoperfusion and organ dysfunction were more expressed when the organism was exposed to endotoxin at a higher rate. These results may facilitate the possibility to choose relevant endotoxin administration, when experiments are set up in order to evaluate certain responses to endotoxaemia. Correlation studies between cytokines, leukocytes, platelets and the endotoxin dose were in agreement with the well-known ability of endotoxin to induce cytokine expression and to activate both primary haemostasis and leukocytes. Free radical mediated lipid peroxidation and COX-mediated inflammation correlated to cytokine expression and organ dysfunction in endotoxaemic shock. Endotoxaemic pigs pretreated with clopidogrel, exhibited a trend towards less expressed deterioration of renal function, although blocking of ADP-induced primary haemostasis is not a key mediator of endotoxin induced deterioration of renal function. Tobramycin did not neutralise the biological effects of endotoxin or the plasma levels of endotoxin, suggesting that these antibiotics do not bind to endotoxin. Reduction in IL-6 was greater in pigs treated with ceftazidime and tobramycin as compared with those given saline, indicating a possible anti-inflammatory effect of both antibiotics.
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