Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains ix, 123 p. : ill. (some col.), maps. Includes abstract. Includes bibliographical references (p. 64-65).

This is a thesis about different methods that can be used to detect spyware. Methods included are Layered Service Provider, Internet Protocol Helper API, TDI filtering and API hooking. Some firewall testing applications, leak tests, that use methods that can be used by real spyware program to penetrate firewalls have also been examined. The goal was to develop a Windows 2000/XP program that is able to detect as many of our examined leak tests as possible. Our program uses the methods TDI filtering and API hooking for detection of spyware because our study showed that these methods were the best. To evaluate the program it was tested against our examined leak test programs. Our program managed to detect all leak tests except one. / Fredrik Bergstrand cfb@home.se Johan Bergstrand jb78@home.se Håkan Gunnarsson hakan.gunnarsson@klostersfalad.se

In the Ottawa Hospital Weight Management Clinic, we have previously identified subpopulations of patients in the upper and lower quintiles for rate of weight loss, and characterized them as ‘obese diet sensitive’ (ODS) and ‘obese diet resistant’ (ODR) patient groups, respectively. Skeletal muscle is a major contributor to basal metabolic rate and mitochondrial proton leak in skeletal muscle can account for up to 50 % of resting oxygen consumption. The overall aim of this research is to explore differences in mitochondrial function in human primary myotubes from ODS and ODR subjects. Subsets of ODS and ODR subjects (n = 9/group) who followed a hypocaloric clinical weight loss program at the Ottawa Weight Management Clinic consented to a muscle (vastus lateralis) biopsy. Human primary myoblasts obtained from biopsies were immunopurified and differentiated into myotubes. Mitochondrial function and distribution were compared in intact myotubes from ODS and ODR subjects. Mitochondrial proton leak was significantly lower (p< 0.05) in ODR myotubes compared to ODS myotubes, independent of whether cells were differentiated in low or high glucose medium. In addition, in low glucose medium, ODR myotubes had higher MnSOD protein levels compared to ODS myotubes (p< 0.05). However, there were no significant differences in mitochondrial content, mitochondrial membrane potential, cellular ROS levels or ATP content between ODS and ODR myotubes. Overall, our in vitro mitochondrial proton leak results are consistent with our previous ex vivo results. Future research should examine the possibility that differences in proton leak between ODS and ODR groups may be related to mechanisms of cellular ROS regulation.

For power plants that make use of high energy boiler feed pumps, there is a risk that the boiler feed pump may experience cavitation and overheating at low load and start-up conditions. These plants make use of a leak off or recirculation system that diverts some of the flow back to the feed water tank, ensuring that a minimum flow through the pump is maintained at low load and start-up operating conditions. The recirculation valve, also known as a leak off valve, experiences a very high pressure difference and cavitation pitting is common due to the water being close to saturation. There are various ways in which the recirculation flow is controlled in the industry such as open orifice, on/off binary type control valves, automatic recirculation valves (ARC) or modern modulating leak off systems. The valves themselves can also be simple plug type or make use of pressure staging to reduce the risk of cavitation. This project involves modelling the flow system around the boiler feed pump and its control for the various architectures employed in Eskom. This is to assist in understanding the reasons for cavitation damage that is found in some recirculation valves as well as the low load capability of the system. Single stage components with extremely high pressure drops are singled out as components with the highest risk of cavitation in the systems. Although extremely high pressure drops are found across the leak off valves themselves, the majority of the valves are multistage valves which are specifically designed to accommodate cavitation development and are therefore not of major concern. Some of the findings of the study are: The rule of thumb used within Eskom to determine the amount of pressure reducing stages on leak off valves could be more conservative. The specification of new valves and components for the leak off systems requires accurate specification based on detailed process models, such as the ones developed for this study. The full range of all possible operational cases must also be considered during the design.

This diploma thesis is focused on the issue of pneumatic components testing and air leakage measurement. The current state of the given issue is summarized based on the analysis of leak testing methods in accordance with valid legislation. The aim of this thesis is to design methods for pneumatic components testing according to specification. As part of method verification, a pneumatic circuit with a pressure control system has been assembled, on which functionality tests of provided components and leak tests by the pressure-drop method have been performed. The results of these tests have been subsequently evaluated as consistent with the specification.

Leakages in the district heating networks is a current and growing problem. To find the leakages today many district heating companies uses manual techniques that are both time consuming and insecure, the methods can leave a lot of leakages in older pipes undiscovered for a very long time. These undetected leakages costs the district heating companies a lot of money and can even be fatal. It is therefor of great importance that the leakages is found in time, thus the methods for leak detection needs to be improved. The main purpose of this thesis was to investigate the ability to use thermal images to automatically search for leakages in district heating systems. To investigate this aerial thermal images from 2013 were collected. Image analysis was performed using ArcGIS and ENVI. This included, among other things, image preprocessing such as to define the projection of the images and unsupervised isodata classification to find potential leakages in the thermal images. This automatic analysis resulted in many false alarms. One example were false alarms caused by vegetation, since vegetation absorbs heat during the day it appears warmer than the surroundings at night. To deal with this problem an unsupervised classification algorithm, isodata, was used again to classify the vegetational areas and the non-vegetational. This algorithm decreased the number of false alarms drastic and thereby increased the usability of the algorithm. Other false alarm that has not been automatically rejected in this thesis were for example false alarms caused by heat leaking from buildings. One way to map such false alarms could be to analyse the shape and the linearisation of the potential leakages close to buildings. This would hugely increase the accuracy of the used algorithm. The provided thermal images used in this thesis consisted of several confirmed leakages. All these confirmed leakages was found by the used algorithm. Although, the accuracy of the used algorithm could be discussed since many false alarms were generated. Nevertheless, to reject false alarms are much less time consuming than manual leak detection for an entire city. Thereby the conclusion that an automatic leak detection in district heating networks is possible, furthermore a leak detection tool like this would be usable for the district heating companies. The evaluations from several different district heating experts who are using Digpro's district heating application, dpHeating, today shows that a leak detection tool using thermal images would be a useful addition in dpHeating.

Pancreatic beta cells sense fluctuations in circulating nutrients and adjust the rate of insulin secretion to maintain glucose homeostasis. Mitochondria integrate changes in nutrient flux to the generation of signals that modulate insulin secretion via oxidative phosphorylation. Type 2 Diabetes (T2D) is characterized by beta cell mitochondrial dysfunction and impairment of insulin secretion. Early stage progression of this disease in obese and pre-diabetic subjects is characterized by basal hypersecretion of insulin and increased insulin resistance in peripheral tissues including muscle, liver and adipose tissue. Whether basal hypersecretion of insulin or insulin resistance is the primary defect in T2D progression is still debated. The molecular mechanism underlying basal insulin hypersecretion and how it may lead to beta cell failure are not understood. Herein, we optimize a model of glucolipotoxicity that results in increased basal and reduced stimulated insulin secretion response. Furthermore, we show that pancreatic islets exposed to excess nutrients in vitro or isolated from high fat diet fed animals, have a decreased bioenergetic efficiency, which is characterized by increased mitochondrial proton leak. Leak represents the fraction of oxygen consumed that is not coupled to ATP production. We show that leak is sufficient to induce insulin secretion at basal glucose levels and that nutrient-induced insulin secretion at basal glucose is leak-dependent. Finally, we identify the mitochondrial permeability transition pore (PTP) as the source of the leak. Our findings suggest the PTP may be a potential therapeutic target to prevent/delay the onset of hyperinsulinemia in pre-diabetic subjects.

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Introduction: Routine drain placement is still widely used in both sleeve gastrectomy (SG) and Roux en Y gastric bypass (REYGB). There is mounting evidence that drains may increase complication risk without preventing reoperation or other complications. Methods: Data from 2017 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) Participant Use File was evaluated for drain use during laparoscopic REYGB and SG. Primary outcomes were superficial and deep surgical site infections (SSI), reintervention/reoperation, and readmission. Preoperative patient risk factors were also compared to evaluate for association with drain placement. Results: A total of 148 260 patients fit the inclusion criteria. Drains were used in 23 190 (15.6%) cases and not used in 125 070 (84.4%). Drain placement during surgery was associated with increased odds of superficial SSI, deep incisional SSI, and organ space SSI. Patients with drains were found to have increased odds of requiring at least 1 reoperation or intervention within 30 days of surgery. Preoperative risk factors associated with drain placement included diabetes mellitus, a history of chronic obstructive pulmonary disease, and oxygen dependence. Smokers were slightly less likely to have a drain placed. There was no significant association with chronic steroid and immunosuppressant usage. Conclusion: There is mounting data against drain placement during bariatric surgery. Prior studies using MBSAQIP data have shown an increased complication rate with drains, and our data set supports the idea that drains may increase complications after surgery. While no randomized prospective trials have been performed looking at drain usage in bariatric surgery, the growing retrospective data certainly inform against the regular use of drains.

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