930 resultados para Line and edge detection
Resumo:
Invasive and exotic species present a serious threat to the health and sustainability of natural ecosystems. These species often benefit from anthropogenic activities that aid their introduction and dispersal. This dissertation focuses on invasion dynamics of the emerald ash borer, native to Asia, and European earthworms. These species have shown detrimental impacts in invaded forest ecosystems across the Great Lakes region, and continue to spread via human-assisted long distance dispersal and by natural modes of dispersal into interior forests from areas of introduction. Successful forest management requires that the impact and effect of invasive species be considered and incorporated into management plans. Understanding patterns and constraints of introduction, establishment, and spread will aid in this effort. To assist in efforts to locate introduction points of emerald ash borer, a multicriteria risk model was developed to predict the highest risk areas. Important parameters in the model were road proximity, land cover type, and campground proximity. The model correctly predicted 85% of known emerald ash borer invasion sites to be at high risk. The model’s predictions across northern Michigan can be used to focus and guide future monitoring efforts. Similar modeling efforts were applied to the prediction of European earthworm invasion in northern Michigan forests. Field sampling provided a means to improve upon modeling efforts for earthworms to create current and future predictions of earthworm invasion. Those sites with high soil pH and high basal area of earthworm preferred overstory species (such as basswood and maples) had the highest likelihood of European earthworm invasion. Expanding beyond Michigan into the Upper Great Lakes region, earthworm populations were sampled across six National Wildlife Refuges to identify potential correlates and deduce specific drivers and constraints of earthworm invasion. Earthworm communities across all refuges were influenced by patterns of anthropogenic activity both within refuges and in surrounding ecoregions of study. Forest composition, soil pH, soil organic matter, anthropogenic cover, and agriculture proximity also proved to be important drivers of earthworm abundance and community composition. While there are few management options to remove either emerald ash borer or European earthworms from forests after they have become well established, prevention and early detection are important and can be beneficial. An improved understanding the factors controlling the distribution and invasion patterns of exotic species across the landscape will aid efforts to determine their consequences and generate appropriate forest management solutions to sustain ecosystem health in the presence of these invaders.
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Micro Combined Heat and Power (Micro-CHP) system produces both electricity and heat required for residential or small business applications. Use of Micro-CHP in a residential application not only creates energy and economic savings but also reduces the carbon foot print of the house or small business. Additionally, micro-CHP can subsidize its cost of operation by selling excess electricity produced back to the grid. Even though Micro-CHP remains attractive on paper, high initial cost and optimization issues in residential scale heat and electrical requirement has kept this technology from becoming a success. To understand and overcome all disadvantages posed my Micro-CHP system, a laboratory is developed to test different scenarios of Micro-CHP applications so that we can learn and improve the current technology. This report focuses on the development of this Micro-CHP laboratory including installation of Ecopower micro-CHP unit, developing fuel line and exhaust line for Ecopower unit, design of electrical and thermal loop, installing all the instrumentation required for data collection on the Ecopower unit and developing controls for heat load simulation using thermal loop. Also a simulation of Micro-CHP running on Syngas is done in Matlab. This work was supported through the donation of ‘Ecopower’ a Micro-CHP unit by Marathon Engine and through the support of Michigan Tech REF-IF grand.
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BACKGROUND: Newborns with hypoplastic left heart syndrome (HLHS) or right heart syndrome or other malformations with a single ventricle physiology and associated hypoplasia of the great arteries continue to be a challenge in terms of survival. The vast majority of these forms of congenital heart defects relate to abnormal morphogenesis during early intrauterine development and can be diagnosed accurately by fetal echocardiography. Early knowledge of these conditions not only permits a better understanding of the progression of these malformations but encourages some researchers to explore new minimally invasive therapeutic options with a view to early pre- and postnatal cardiac palliation. DATA SOURCES: PubMed database was searched with terms of "congenital heart defects", "fetal echocardiography" and "neonatal cardiac surgery". RESULTS: At present, early prenatal detection has been applied for monitoring pregnancy to avoid intrauterine cardiac decompensation. In principle, the majority of congenital heart defects can be diagnosed by prenatal echocardiography and the detection rate is 85%-95% at tertiary perinatal centers. The majority, particularly of complex congenital lesions, show a steadily progressive course including subsequent secondary phenomena such as arrhythmias or myocardial insufficiency. So prenatal treatment of an abnormal fetus is an area of perinatal medicine that is undergoing a very dynamic development. Early postnatal treatment is established for some time, and prenatal intervention or palliation is at its best experimental stage in individual cases. CONCLUSION: The upcoming expansion of fetal cardiac intervention to ameliorate critically progressive fetal lesions intensifies the need to address issues about the adequacy of technological assessment and patient selection as well as the morbidity of those who undergo these procedures.
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PCR tests for the rapid and valid detection of methicillin-resistant Staphylococcus aureus (MRSA) are now available. We evaluated the costs associated with contact screening for MRSA carriage in a tertiary-care hospital with low MRSA endemicity. Between 1 October 2005 and 28 February 2006, 232 patients were screened during 258 screening episodes (644 samples) for MRSA carriage by GenoType MRSA Direct (Hain Lifescience GmbH, Nehren, Germany). Conventional culture confirmed all PCR results. According to in-house algorithms, 34 of 258 screening episodes (14.7%) would have qualified for preemptive contact isolation, but such isolation was not done upon negative PCR results. MRSA carriage was detected in 4 (1.5%) of 258 screening episodes (i.e., in four patients), of which none qualified for preemptive contact isolation. The use of PCR for all 258 screening episodes added costs (in Swiss francs [CHF]) of CHF 104,328.00 and saved CHF 38,528.00 (for preemptive isolation). The restriction of PCR screening to the 34 episodes that qualified for preemptive contact isolation and screening all others by culture would have lowered costs for PCR to only CHF 11,988.00, a savings of CHF 38,528.00. Therefore, PCR tests are valuable for the rapid detection of MRSA carriers, but high costs require the careful evaluation of their use. In patient populations with low MRSA endemicity, the broad use of PCR probably is not cost-effective.
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In this thesis, I study skin lesion detection and its applications to skin cancer diagnosis. A skin lesion detection algorithm is proposed. The proposed algorithm is based color information and threshold. For the proposed algorithm, several color spaces are studied and the detection results are compared. Experimental results show that YUV color space can achieve the best performance. Besides, I develop a distance histogram based threshold selection method and the method is proven to be better than other adaptive threshold selection methods for color detection. Besides the detection algorithms, I also investigate GPU speed-up techniques for skin lesion extraction and the results show that GPU has potential applications in speeding-up skin lesion extraction. Based on the skin lesion detection algorithms proposed, I developed a mobile-based skin cancer diagnosis application. In this application, the user with an iPhone installed with the proposed application can use the iPhone as a diagnosis tool to find the potential skin lesions in a persons' skin and compare the skin lesions detected by the iPhone with the skin lesions stored in a database in a remote server.
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Quantitative reverse transcriptase real-time PCR (QRT-PCR) is a robust method to quantitate RNA abundance. The procedure is highly sensitive and reproducible as long as the initial RNA is intact. However, breaks in the RNA due to chemical or enzymatic cleavage may reduce the number of RNA molecules that contain intact amplicons. As a consequence, the number of molecules available for amplification decreases. We determined the relation between RNA fragmentation and threshold values (Ct values) in subsequent QRT-PCR for four genes in an experimental model of intact and partially hydrolyzed RNA derived from a cell line and we describe the relation between RNA integrity, amplicon size and Ct values in this biologically homogenous system. We demonstrate that degradation-related shifts of Ct values can be compensated by calculating delta Ct values between test genes and the mean values of several control genes. These delta Ct values are less sensitive to fragmentation of the RNA and are unaffected by varying amounts of input RNA. The feasibility of the procedure was demonstrated by comparing Ct values from a larger panel of genes in intact and in partially degraded RNA. We compared Ct values from intact RNA derived from well-preserved tumor material and from fragmented RNA derived from formalin-fixed, paraffin-embedded (FFPE) samples of the same tumors. We demonstrate that the relative abundance of gene expression can be based on FFPE material even when the amount of RNA in the sample and the extent of fragmentation are not known.
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A series of C-3 alkyl and arylalky 2,3-dideoxy hex-2-enopyranoside derivatives were synthesized by Morita-Baylis-Hillman reaction using enulosides 4, 5 and 6 and various aliphatic and aromatic aldehydes. The compounds were evaluated in vitro for the complete inhibition of growth of Mycobacterium tuberculosis H37Rv. They exhibited moderate to good activity in the range of 25-1.56 µg/mL. Among these, 4d, 4h, 5c and 4hr showed activity at minimum inhibitory concentrations, 3.12, 6.25, 1.56 and 1.56µg/mL, respectively. These compounds were safe against cytotoxicity in VERO cell line and mouse macrophage cell line J 744A.1. A QSAR analysis by CP-MLR with alignment-free 3D-descriptors indicated the relevance of structure space comparable to the minimum energy conformation (from conformational analysis) of 5c to the activity. The study indicates that the compounds attaining conformational space 5c and reflecting some symmetry, minimum eccentricity and closely placed geometric and electronegativity centers therein are favorable for activity.
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Neurons in Action (NIA1, 2000; NIA1.5, 2004; NIA2, 2007), a set of tutorials and linked simulations, is designed to acquaint students with neuronal physiology through interactive, virtual laboratory experiments. Here we explore the uses of NIA in lecture, both interactive and didactic, as well as in the undergraduate laboratory, in the graduate seminar course, and as an examination tool through homework and problem set assignments. NIA, made with the simulator NEURON (http://www.neuron.yale.edu/neuron/), displays voltages, currents, and conductances in a membrane patch or signals moving within the dendrites, soma and/or axon of a neuron. Customized simulations start with the plain lipid bilayer and progress through equilibrium potentials; currents through single Na and K channels; Na and Ca action potentials; voltage clamp of a patch or a whole neuron; voltage spread and propagation in axons, motoneurons and nerve terminals; synaptic excitation and inhibition; and advanced topics such as channel kinetics and coincidence detection. The user asks and answers "what if" questions by specifying neuronal parameters, ion concentrations, and temperature, and the experimental results are then plotted as conductances, currents, and voltage changes. Such exercises provide immediate confirmation or refutation of the student's ideas to guide their learning. The tutorials are hyperlinked to explanatory information and to original research papers. Although the NIA tutorials were designed as a sequence to empower a student with a working knowledge of fundamental neuronal principles, we find that faculty are using the individual tutorials in a variety of educational situations, some of which are described here. Here we offer ideas to colleagues using interactive software, whether NIA or another tool, for educating students of differing backgrounds in the subject of neurophysiology.
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BACKGROUND Little is known about the potential benefit of skin self-examination for melanoma prevention and early detection. Objectives: To determine whether skin self-examination is associated with reduced melanoma risk, self-detection of tumours, and reduced risk of deeper melanomas. METHODS We used data from a population-based case-control study (423 cases, 678 controls) to assess recent skin self-examination in relation to self-detection, melanoma risk and tumour depth ( ≤1 mm; > 1 mm). Logistic regression was used to estimate odds ratios (ORs) and confidence intervals (CIs) for associations of interest. RESULTS Skin self-examination conducted 1-11 times during a recent year was associated with a possible decrease in melanoma risk (OR 0·74; 95% CI 0·54-1·02). Melanoma risk was decreased for those who conducted skin self-examination and saw a doctor (OR 0·52; 95% CI 0·30-0·90). Among cases, those who examined their skin were twice as likely to self-detect the melanoma (OR 2·23; 95% CI 1·47-3·38), but self-detection was not associated with shallower tumours. Tumour depth was reduced for those who conducted skin self-examination 1-11 times during a recent year (OR 0·39; 95% CI 0·18-0·81), but was not influenced by seeing a doctor, or by conducting skin self-examination and seeing a doctor. CONCLUSIONS Risk of a deeper tumour and possibly risk of melanoma were reduced by skin self-examination 1-11 times annually. Melanoma risk was markedly reduced by skin self-examination coupled with a doctor visit. We cannot, however, exclude the possibility that our findings reflect bias or confounding. Additional studies are needed to elucidate the potential benefits of skin self-examination for melanoma prevention and early detection.
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Abstract concepts like numbers or time are thought to be represented in the more concrete domain of space and the sensorimotor system. For example, thinking of past or future events has a physical manifestation in backward or forward body sway, respectively. In the present study, we investigated the reverse effect: can passive whole-body motion influence the processing of temporal information? Participants were asked to categorize verbal stimuli to the concepts future or past while they were displaced forward and backward (Experiment 1), or upward and downward (Experiment 2). The results showed that future related verbal stimuli were categorized faster during forward as compared to backward motion. This finding supports the view that temporal events are represented along a mental time line and that the sensorimotor system is linked to that representation. We showed that body motion is not just an epiphenomenon of temporal thoughts. Passive whole-body motion can influence higher-order temporal cognition.
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Periodically-harvested closures are commonly employed within co-management frameworks to help manage small-scale, multi-species fisheries in the Indo-Pacific. Despite their widespread use, the benefits of periodic harvesting strategies for multi-species fisheries have, to date, been largely untested. We examine catch and effort data from four periodically-harvested reef areas and 55 continuously-fished reefs in Solomon Islands. We test the hypothesis that fishing in periodically-harvested closures would yield: (a) higher catch rates, (b) proportionally more short lived, fast growing, sedentary taxa, and (c) larger finfish and invertebrates, compared to catches from reefs continuously open to fishing. Our study showed that catch rates were significantly higher from periodically-harvested closures for gleaning of invertebrates, but not for line and spear fishing. The family level composition of catches did not vary significantly between open reefs and periodically-harvested closures. Fish captured from periodically-harvested closures were slightly larger, but Trochus niloticus were significantly smaller than those from continuously open reefs. In one case of intense and prolonged harvesting, gleaning catch rates significantly declined, suggesting invertebrate stocks were substantially depleted in the early stages of the open period. Our study suggests periodically-harvested closures can have some short term benefits via increasing harvesting efficiency. However, we did not find evidence that the strategy had substantially benefited multi-species fin-fisheries.
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Amylase activity in exhaled breath condensate (EBC) is usually interpreted as an indication of oropharyngeal contamination despite the fact that amylase can be found in pulmonary excretions. The aim of this study was to recruit and refine an amylase assay in order to detect amylase activity in any EBC sample and to develop a method to identify EBC samples containing amylase of pulmonary origin. EBC was collected from 40 volunteers with an EcoScreen condenser. Amylase assays and methods to discriminate between oropharyngeal and pulmonary proteins were tested and developed using matched EBC and saliva samples. Our refined 2-chloro-4-nitrophenyl-α-D-maltotriosid (CNP-G3) assay was 40-fold more sensitive than the most sensitive commercial assay and allowed detection of amylase activity in 30 µl of EBC. We developed a dot-blot assay which allowed detection of salivary protein in saliva diluted up to 150 000-fold. By plotting amylase activity against staining intensity we identified a few EBC samples with high amylase activity which were aligned with diluted saliva. We believe that EBC samples aligned with diluted saliva contain amylase activity introduced during EBC collection and that all other EBC samples contain amylase activity of pulmonary origin and are basically free of oropharyngeal protein contamination.
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BACKGROUND Small benign insulinomas are hard to localise, leading to difficulties in planning of surgical interventions. We aimed to prospectively assess the insulinoma detection rate of single-photon emission CT in combination with CT (SPECT/CT) with a glucagon-like peptide-1 receptor avid radiotracer, and compare detection rates with conventional CT/MRI techniques. METHODS In our prospective imaging study, we enrolled adults aged 25-81 years at centres in Germany, Switzerland, and the UK. Eligible patients had proven clinical and biochemical endogenous hyperinsulinaemic hypoglycaemia and no evidence for metastatic disease on conventional imaging. CT/MRI imaging was done at referring centres according to standard protocols. At three tertiary nuclear medicine centres, we used whole body planar images and SPECT/CT of the abdomen up to 168 h after injection of (111)In-[Lys40(Ahx-DTPA-(111)In)NH2]-exendin-4 ((111)In-DTPA-exendin-4) to identify insulinomas. Consenting patients underwent surgery and imaging findings were confirmed histologically. FINDINGS Between Oct 1, 2008, and Dec 31, 2011, we recruited 30 patients. All patients underwent (111)In-DTPA-exendin-4 imaging, 25 patients underwent surgery (with histological analysis), and 27 patients were assessed with CT/MRI. (111)In-DTPA-exendin-4 SPECT/CT correctly detected 19 insulinomas and four additional positive lesions (two islet-cell hyperplasia and two uncharacterised lesions) resulting in a positive predictive value of 83% (95% CI 62-94). One true negative (islet-cell hyperplasia) and one false negative (malignant insulinoma) result was identified in separate patients by (111)In-DTPA-exendin-4 SPECT/CT. Seven patients (23%) were referred to surgery on the basis of (111)In-DTPA-exendin-4 imaging alone. For 23 assessable patients, (111)In-DTPA-exendin-4 SPECT/CT had a higher sensitivity (95% [95% CI 74-100]) than did CT/MRI (47% [27-68]; p=0·011). INTERPRETATION (111)In-DTPA-exendin-4 SPECT/CT could provide a good second-line imaging strategy for patients with negative results on initial imaging with CT/MRI. FUNDING Oncosuisse, the Swiss National Science Foundation, and UK Department of Health.
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BACKGROUND: Arginine metabolism in tumor cell lines can be influenced by various cytokines, including recombinant human interferon-gamma (rIFN-gamma), a cytokine that shows promising clinical activity in epithelial ovarian cancer (EOC). METHODS: We examined EOC cell lines for the expression of arginase in an enzymatic assay and for transcripts of arginase I and II, inducible nitric oxide synthase (iNOS), and indoleamine 2,3-dioxygenase (IDO) by reverse transcription-polymerase chain reaction. The effects of rIFN-gamma on arginase activity and on tumor cell growth inhibition were determined by measuring [3H]thymidine uptake. RESULTS: Elevated arginase activity was detected in 5 of 8 tumor cell lines, and analysis at the transcriptional level showed that arginase II was involved but arginase I was not. rIFN-gamma reduced arginase activity in 3 EOC cell lines but increased activity in the 2008 cell line and its platinum-resistant subline, 2008.C13. iNOS transcripts were not detected in rIFN-gamma-treated or untreated cell lines. In contrast, IDO activity was induced or increased by rIFN-gamma. Suppression of arginase activity by rIFN-gamma in certain cell lines suggested that such inhibition might contribute to its antiproliferative effects. However, supplementation of the medium with polyamine pathway products did not interfere with the growth-inhibitory effects of rIFN-gamma EOC cells. CONCLUSIONS: Increased arginase activity, specifically identified with arginase II, is present in most of the tested EOC cell lines. rIFN-gamma inhibits or stimulates arginase activity in certain EOC cell lines, though the decrease in arginase activity does not appear to be associated with the in vitro antiproliferative activity of rIFN-gamma. Since cells within the stroma of EOC tissues could also contribute to arginine metabolism following treatment with rIFN-gamma or rIFN-gamma-inducers, it would be helpful to examine these effects in vivo.
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Measurement of perfusion in longitudinal studies allows for the assessment of tissue integrity and the detection of subtle pathologies. In this work, the feasibility of measuring brain perfusion in rats with high spatial resolution using arterial spin labeling is reported. A flow-sensitive alternating recovery sequence, coupled with a balanced gradient fast imaging with steady-state precession readout section was used to minimize ghosting and geometric distortions, while achieving high signal-to-noise ratio. The quantitative imaging of perfusion using a single subtraction method was implemented to address the effects of variable transit delays between the labeling of spins and their arrival at the imaging slice. Studies in six rats at 7 T showed good perfusion contrast with minimal geometric distortion. The measured blood flow values of 152.5+/-6.3 ml/100 g per minute in gray matter and 72.3+/-14.0 ml/100 g per minute in white matter are in good agreement with previously reported values based on autoradiography, considered to be the gold standard.