677 research outputs found

    The Parametric Inverse Problem in Transient Scattering

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    Scattering problems in many areas of applied physics are governed by the wave equation. In the most usual situation, we are given the incident wave (input) and the scatterer(s) and attempt, through analytical, experimental, or numerical methods, to produce the scattered waves (output). Such procedures can be carried out in either the frequency domain or the time domain and are categorized under the general heading of “forward problems.” In a less usual, but no less important situation, we are given the incident wave (input) and the scattered waves (output) and attempt to find the scatterer(s) that produced the output. In this case, we call the procedures “inverse” problems

    Generational status and duration of residence predict diabetes prevalence among Latinos: the California Men's Health Study

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    <p>Abstract</p> <p>Background</p> <p>Diabetes disproportionately affects Latinos. However, examining Latinos as one group obscures important intra-group differences. This study examined how generational status, duration of US residence, and language preference are associated with diabetes prevalence and to what extent these explain the higher prevalence among Latinos.</p> <p>Methods</p> <p>We determined nativity, duration of US residence, language preference, and diabetes prevalence among 11 817 Latino, 6109 black, and 52 184 white participants in the California Men's Health Study. We combined generational status and residence duration into a single migration status variable with levels: ≥ third generation; second generation; and immigrant living in the US for > 25, 16-25, 11-15, or ≤ 10 years. Language preference was defined as language in which the participant took the survey. Logistic regression models were specified to assess the associations of dependent variables with prevalent diabetes.</p> <p>Results</p> <p>Diabetes prevalence was 22%, 23%, and 11% among Latinos, blacks, and whites, respectively. In age-adjusted models, we observed a gradient of risk of diabetes by migration status among Latinos. Further adjustment for socioeconomic status, obesity and health behaviors only partially attenuated this gradient. Language preference was a weak predictor of prevalent diabetes in some models and not significant in others. In multivariate models, we found that odds of diabetes were higher among US-born Latinos than US-born blacks.</p> <p>Conclusion</p> <p>Generational status and residence duration were associated with diabetes prevalence among middle-aged Latino men in California. As the Latino population grows, the burden of diabetes-associated disease is likely to increase and demands public health attention.</p

    Dyspnea assessment and adverse events during sputum induction in COPD

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    BACKGROUND: The inhalation of normal or hypertonic saline during sputum induction (SI) may act as an indirect bronchoconstrictive stimulus leading to dyspnea and lung function deterioration. Our aim was to assess dyspnea and adverse events in COPD patients who undergo SI following a safety protocol. METHODS: Sputum was induced by normal and hypertonic (4.5%) saline solution in 65 patients with COPD of varying severity. In order to minimize saline-induced bronchoconstriction a protocol based on the European Respiratory Society sputum induction Task group report was followed. Dyspnea change was scored using the Borg scale and lung function was assessed by spirometry and oximetry. RESULTS: Borg score changes [median(IQR) 1.5(0–2)] were observed during SI in 40 subjects; 16 patients required temporary discontinuation of the procedure due to dyspnea-general discomfort and 2 did not complete the session due to dyspnea-wheezing. The change in Borg dyspnea score was significantly correlated with oxygen saturation and heart rate changes and with discontinuation of the procedure due to undesired symptoms. 19 subjects presented an hyperresponsive reaction (decline>20% from baseline FEV(1)). No significant correlation between Borg changes and FEV(1)decline was found. Patients with advanced COPD presented significantly greater Borg and oxygen saturation changes than patients with less severe disease (p = 0.02 and p = 0.001, respectively). Baseline FEV(1), oxygen saturation and 6MWT demonstrated significant diagnostic values in distinguishing subjects who develop an adverse physiologic reaction during the procedure. CONCLUSION: COPD patients undergoing SI following a safety protocol do not experience major adverse events. Dyspnea and oxygen desaturation is more likely to occur in patients with disease in advanced stages, leading to short discontinuation or less frequently to termination of the procedure. Baseline FEV(1), oxygen saturation and 6MWT may have a prognostic value for the development of these adverse events and might be useful to be evaluated in advance

    Individualised therapy of angiotensin converting enzyme (ACE) inhibitors in stable coronary artery disease: overview of the primary results of the PERindopril GENEtic association (PERGENE) study

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    In patients with stable coronary artery disease (CAD) without overt heart failure, ACE inhibitors are among the most commonly used drugs as these agents have been proven effective in reducing the risk of cardiovascular events. Considerable individual variations in the blood pressure response to ACE inhibitors are observed and as such heterogeneity in clinical treatment effect would be likely as well. Assessing the consistency of treatment benefit is essential for the rational and cost-effective prescription of ACE inhibitors. Information on heterogeneities in treatment effect between subgroups of patients could be used to develop an evidence-based guidance for the installation of ACE-inhibitor therapy. Obviously, therapy should only be applied in those patients who most likely will benefit. Attempts to develop such treatment guidance by using clinical characteristics have been unsuccessful. No heterogeneity in risk reduction by ACE inhibitors has been observed in relation to relevant clinical characteristics. A new approach to such ‘guided-therapy’ could be to integrate more patient-specific characteristics such as the patients’ genetic information. If proven feasible, pharmacogenetic profiling could optimise patients’ benefit of treatment and reduce unnecessary treatment of patients. Cardiovascular pharmacogenetic research of ACE inhibitors in coronary artery disease patients is in a formative stage and studies are limited. The PERGENE study is a large pharmacogenetic substudy of the EUROPA trial, aimed to assess the achievability of pharmacogenetic profiling. We provide an overview of the main results of the PERGENE study in terms of the genetic determinants of treatment benefit and blood pressure response. The main results of the PERGENE study show a pharmacogenetic profile related to the treatment benefit of perindopril identifying responders and non-responders to treatment

    Markers of Dysglycaemia and Risk of Coronary Heart Disease in People without Diabetes: Reykjavik Prospective Study and Systematic Review

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    BACKGROUND: Associations between circulating markers of dysglycaemia and coronary heart disease (CHD) risk in people without diabetes have not been reliably characterised. We report new data from a prospective study and a systematic review to help quantify these associations. METHODS AND FINDINGS: Fasting and post-load glucose levels were measured in 18,569 participants in the population-based Reykjavik study, yielding 4,664 incident CHD outcomes during 23.5 y of mean follow-up. In people with no known history of diabetes at the baseline survey, the hazard ratio (HR) for CHD, adjusted for several conventional risk factors, was 2.37 (95% CI 1.79-3.14) in individuals with fasting glucose > or = 7.0 mmol/l compared to those or = 7 mmol/l at baseline were excluded, relative risks for CHD, adjusted for several conventional risk factors, were: 1.06 (1.00-1.12) per 1 mmol/l higher fasting glucose (23 cohorts, 10,808 cases, 255,171 participants); 1.05 (1.03-1.07) per 1 mmol/l higher post-load glucose (15 cohorts, 12,652 cases, 102,382 participants); and 1.20 (1.10-1.31) per 1% higher HbA(1c) (9 cohorts, 1639 cases, 49,099 participants). CONCLUSIONS: In the Reykjavik Study and a meta-analysis of other Western prospective studies, fasting and post-load glucose levels were modestly associated with CHD risk in people without diabetes. The meta-analysis suggested a somewhat stronger association between HbA(1c) levels and CHD risk

    Born to be green: new insights into the economics and management of green entrepreneurship

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    While the number of green start-ups has steadily increased around the world in response to the environmental problems demanding immediate solutions, there are several unresolved questions on the behaviour and performance of such ventures. The papers in this special issue shed light on these issues by underscoring the role of several factors, such as industry life cycles, knowledge spillovers, institutions, and availability of external finance, in shaping decision-making and firm behaviour in green start-ups. This paper highlights the state-of-the art developments in the literature, discusses the key contributions of the papers put together in this special issue and presents a future research agenda for scholars interested in green entrepreneurship

    Significance of Cuscutain, a cysteine protease from Cuscuta reflexa, in host-parasite interactions

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    <p>Abstract</p> <p>Background</p> <p>Plant infestation with parasitic weeds like <it>Cuscuta reflexa </it>induces morphological as well as biochemical changes in the host and the parasite. These modifications could be caused by a change in protein or gene activity. Using a comparative macroarray approach <it>Cuscuta </it>genes specifically upregulated at the host attachment site were identified.</p> <p>Results</p> <p>One of the infestation specific <it>Cuscuta </it>genes encodes a cysteine protease. The protein and its intrinsic inhibitory peptide were heterologously expressed, purified and biochemically characterized. The haustoria specific enzyme was named cuscutain in accordance with similar proteins from other plants, e.g. papaya. The role of cuscutain and its inhibitor during the host parasite interaction was studied by external application of an inhibitor suspension, which induced a significant reduction of successful infection events.</p> <p>Conclusions</p> <p>The study provides new information about molecular events during the parasitic plant - host interaction. Inhibition of cuscutain cysteine proteinase could provide means for antagonizing parasitic plants.</p
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