18 research outputs found

    Application of Differential and Polarimetric Synthetic Aperture Radar (SAR) Interferometry for Studying Natural Hazards

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    In the following work, I address the problem of coherence loss in standard Differential Interferometric SAR (DInSAR) processing, which can result in incomplete or poor quality deformation measurements in some areas. I incorporate polarimetric information with DInSAR in a technique called Polarimetric SAR Interferometry (PolInSAR) in order to acquire more accurate and detailed maps of surface deformation. In Chapter 2, I present a standard DInSAR study of the Ahar double earthquakes (Mw=6.4 and 6.2) which occurred in northwest Iran, August 11, 2012. The DInSAR coseismic deformation map was affected by decorrelation noise. Despite this, I employed an advanced inversion technique, in combination with a Coulomb stress analysis, to find the geometry and the slip distribution on the ruptured fault plane. The analysis shows that the two earthquakes most likely occurred on a single fault, not on conjugate fault planes. This further implies that the minor strike-slip faults play more significant role in accommodating convergence stress accumulation in the northwest part of Iran. Chapter 3 presents results from the application of PolInSAR coherence optimization on quad-pol RADARSAT-2 images. The optimized solution results in the identification of a larger number of reliable measurement points, which otherwise are not recognized by the standard DInSAR technique. I further assess the quality of the optimized interferometric phase, which demonstrates an increased phase quality with respect to those phases recovered by applying standard DInSAR alone. Chapter 4 discusses results from the application of PolInSAR coherence optimization from different geometries to the study of creep on the Hayward fault and landslide motions near Berkeley, CA. The results show that the deformation rates resolved by PolInSAR are in agreement with those of standard DInSAR. I also infer that there is potential motion on a secondary fault, northeast and parallel to the Hayward fault, which may be creeping with a lower velocity

    Investigation of the Effect of Aging on Health Costs: A Systematic Review

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    Background & Objectives: Aging and the need for more health care in the elderly population have incurred large expenditures. Based on the importance of the aging population phenomenon and the increase in lifetime in recent decades, this study aimed to systematically review the studies on costs of elderly health care. Methods: In this systematic review, the articles published in PubMed Google Scholar, Science Direct, Scopus, and Ovid Medline databases from 2000 to 2017 were derived using a systematic search strategy. Results: The results of the reviewed studies showed that by increasing the consumption of long-term care and home care, the costs would increase and by reducing the consumption of acute hospital care, such costs would decrease. Based on the results, the average cost of elderly health care in the reviewed studies was 48101 US dollars in 2015. Moreover, the highest average costs were for inpatient services (19003US dollars) and long-term care and home care (12583US dollars). Conclusion: Considering the high costs of hospitalization of the elderly, measures like establishment of day care centers and home care instead of hospitalization should be taken into consideration in the elderly health care programs to reduce the number of hospitalizations. Key¬words: Aging, the Elderly, Health Costs, Hospital Costs, Systematic Review Citation: Rezapour A, Arabloo J, Alipour V, Alipour S. Investigation of the Effect of Aging on Health Costs: A Systematic Review. Journal of Health Based Research 2020; 5(4): 411-22. [In Persian

    The Potential Anti-inflammatory Effect of Spirulina Platensis on an in Vitro Model of Celiac Disease

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    Background: Celiac disease (CD) is a prevalent autoimmune enteropathy triggered by the ingestion of gluten. The management of CD involves adhering to a gluten-free diet (GFD). Recent studies have been actively exploring potential supplementary or alternative therapies for individuals with CD. The primary objective of the present study was to assess the effectiveness of Spirulina platensis in regulating the intestinal barrier-related gene expression and alleviating inflammation and oxidative stress associated with CD in PT-gliadin-triggered Caco-2 cells.Methods: S. platensis extracts and a pepsin/trypsin (PT) digest of gliadin were prepared and exposed to the human colon carcinoma Caco-2 cell line. Cell viability was assessed. Total RNA was extracted from Caco-2 cells and cDNA synthesis was performed. A quantitative real-time polymerase chain reaction (qRT-PCR) assay was conducted to evaluate the mRNA levels of interleukin (IL)-6, transforming growth factor beta (TGF-β), COX-2, nuclear factor kappa B (NF-κB), ZO-1, and occludin.Results: Treating Caco-2 cells with S. platensis alone (P=0.01 for both) or in combination with PT-gliadin (P=0.004 and P=0.02, respectively) resulted in decreased IL-6 expression and increased occludin mRNA expression. Additionally, S. platensis extract enhanced Zo-1 mRNA levels (P=0.002) and reduced NF-κB mRNA expression (P=0.02). The combination of gliadin and S. platensis led to decreased mRNA expression of COX-2 (P=0.03) and NF-κB (P=0.04). No significant differences were observed in TGF-β mRNA expression between the studied groups (P>0.05).Conclusion: Additional investigation is needed to examine the influence of interactions between S. platensis and gliadin regarding the comprehensive response of CD to gliadin, encompassing the activation of gluten-sensitive immune cells

    Estimates, trends, and drivers of the global burden of type 2 diabetes attributable to PM2.5 air pollution, 1990-2019 : an analysis of data from the Global Burden of Disease Study 2019

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    Background Experimental and epidemiological studies indicate an association between exposure to particulate matter (PM) air pollution and increased risk of type 2 diabetes. In view of the high and increasing prevalence of diabetes, we aimed to quantify the burden of type 2 diabetes attributable to PM2.5 originating from ambient and household air pollution.Methods We systematically compiled all relevant cohort and case-control studies assessing the effect of exposure to household and ambient fine particulate matter (PM2.5) air pollution on type 2 diabetes incidence and mortality. We derived an exposure-response curve from the extracted relative risk estimates using the MR-BRT (meta-regression-Bayesian, regularised, trimmed) tool. The estimated curve was linked to ambient and household PM2.5 exposures from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019, and estimates of the attributable burden (population attributable fractions and rates per 100 000 population of deaths and disability-adjusted life-years) for 204 countries from 1990 to 2019 were calculated. We also assessed the role of changes in exposure, population size, age, and type 2 diabetes incidence in the observed trend in PM2.5-attributable type 2 diabetes burden. All estimates are presented with 95% uncertainty intervals.Findings In 2019, approximately a fifth of the global burden of type 2 diabetes was attributable to PM2.5 exposure, with an estimated 3.78 (95% uncertainty interval 2.68-4.83) deaths per 100 000 population and 167 (117-223) disability-adjusted life-years (DALYs) per 100 000 population. Approximately 13.4% (9.49-17.5) of deaths and 13.6% (9.73-17.9) of DALYs due to type 2 diabetes were contributed by ambient PM2.5, and 6.50% (4.22-9.53) of deaths and 5.92% (3.81-8.64) of DALYs by household air pollution. High burdens, in terms of numbers as well as rates, were estimated in Asia, sub-Saharan Africa, and South America. Since 1990, the attributable burden has increased by 50%, driven largely by population growth and ageing. Globally, the impact of reductions in household air pollution was largely offset by increased ambient PM2.5.Interpretation Air pollution is a major risk factor for diabetes. We estimated that about a fifth of the global burden of type 2 diabetes is attributable PM2.5 pollution. Air pollution mitigation therefore might have an essential role in reducing the global disease burden resulting from type 2 diabetes. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd.Peer reviewe

    Estimates, trends, and drivers of the global burden of type 2 diabetes attributable to PM2.5 air pollution, 1990-2019 : An analysis of data from the Global Burden of Disease Study 2019

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    Background Experimental and epidemiological studies indicate an association between exposure to particulate matter (PM) air pollution and increased risk of type 2 diabetes. In view of the high and increasing prevalence of diabetes, we aimed to quantify the burden of type 2 diabetes attributable to PM2·5 originating from ambient and household air pollution. Methods We systematically compiled all relevant cohort and case-control studies assessing the effect of exposure to household and ambient fine particulate matter (PM2·5) air pollution on type 2 diabetes incidence and mortality. We derived an exposure–response curve from the extracted relative risk estimates using the MR-BRT (meta-regression—Bayesian, regularised, trimmed) tool. The estimated curve was linked to ambient and household PM2·5 exposures from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019, and estimates of the attributable burden (population attributable fractions and rates per 100 000 population of deaths and disability-adjusted life-years) for 204 countries from 1990 to 2019 were calculated. We also assessed the role of changes in exposure, population size, age, and type 2 diabetes incidence in the observed trend in PM2·5-attributable type 2 diabetes burden. All estimates are presented with 95% uncertainty intervals. Findings In 2019, approximately a fifth of the global burden of type 2 diabetes was attributable to PM2·5 exposure, with an estimated 3·78 (95% uncertainty interval 2·68–4·83) deaths per 100 000 population and 167 (117–223) disability-adjusted life-years (DALYs) per 100 000 population. Approximately 13·4% (9·49–17·5) of deaths and 13·6% (9·73–17·9) of DALYs due to type 2 diabetes were contributed by ambient PM2·5, and 6·50% (4·22–9·53) of deaths and 5·92% (3·81–8·64) of DALYs by household air pollution. High burdens, in terms of numbers as well as rates, were estimated in Asia, sub-Saharan Africa, and South America. Since 1990, the attributable burden has increased by 50%, driven largely by population growth and ageing. Globally, the impact of reductions in household air pollution was largely offset by increased ambient PM2·5. Interpretation Air pollution is a major risk factor for diabetes. We estimated that about a fifth of the global burden of type 2 diabetes is attributable PM2·5 pollution. Air pollution mitigation therefore might have an essential role in reducing the global disease burden resulting from type 2 diabetes

    Global, regional, and national cancer incidence, mortality, years of life lost, years lived with disability, and disability-Adjusted life-years for 29 cancer groups, 1990 to 2017 : A systematic analysis for the global burden of disease study

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    Importance: Cancer and other noncommunicable diseases (NCDs) are now widely recognized as a threat to global development. The latest United Nations high-level meeting on NCDs reaffirmed this observation and also highlighted the slow progress in meeting the 2011 Political Declaration on the Prevention and Control of Noncommunicable Diseases and the third Sustainable Development Goal. Lack of situational analyses, priority setting, and budgeting have been identified as major obstacles in achieving these goals. All of these have in common that they require information on the local cancer epidemiology. The Global Burden of Disease (GBD) study is uniquely poised to provide these crucial data. Objective: To describe cancer burden for 29 cancer groups in 195 countries from 1990 through 2017 to provide data needed for cancer control planning. Evidence Review: We used the GBD study estimation methods to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-Adjusted life-years (DALYs). Results are presented at the national level as well as by Socio-demographic Index (SDI), a composite indicator of income, educational attainment, and total fertility rate. We also analyzed the influence of the epidemiological vs the demographic transition on cancer incidence. Findings: In 2017, there were 24.5 million incident cancer cases worldwide (16.8 million without nonmelanoma skin cancer [NMSC]) and 9.6 million cancer deaths. The majority of cancer DALYs came from years of life lost (97%), and only 3% came from years lived with disability. The odds of developing cancer were the lowest in the low SDI quintile (1 in 7) and the highest in the high SDI quintile (1 in 2) for both sexes. In 2017, the most common incident cancers in men were NMSC (4.3 million incident cases); tracheal, bronchus, and lung (TBL) cancer (1.5 million incident cases); and prostate cancer (1.3 million incident cases). The most common causes of cancer deaths and DALYs for men were TBL cancer (1.3 million deaths and 28.4 million DALYs), liver cancer (572000 deaths and 15.2 million DALYs), and stomach cancer (542000 deaths and 12.2 million DALYs). For women in 2017, the most common incident cancers were NMSC (3.3 million incident cases), breast cancer (1.9 million incident cases), and colorectal cancer (819000 incident cases). The leading causes of cancer deaths and DALYs for women were breast cancer (601000 deaths and 17.4 million DALYs), TBL cancer (596000 deaths and 12.6 million DALYs), and colorectal cancer (414000 deaths and 8.3 million DALYs). Conclusions and Relevance: The national epidemiological profiles of cancer burden in the GBD study show large heterogeneities, which are a reflection of different exposures to risk factors, economic settings, lifestyles, and access to care and screening. The GBD study can be used by policy makers and other stakeholders to develop and improve national and local cancer control in order to achieve the global targets and improve equity in cancer care. © 2019 American Medical Association. All rights reserved.Peer reviewe

    An Exact Scheme for the EIT for a Three-level L-Type Atom in a Quantum Cavity

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    Semi-quantum or full-quantum electromagnetically induced transparency has been fully studied for three-level atoms in a weak field approximation method, where probe field is very weaker than the coupling field. The weak field approximation is not valid in full-quantum model where the number of coupling photons is not so large. In the present article, the master equations for the interaction of two-mode photons with a three-level L-type atom are exactly solved and the exact dispersion and absorption spectra for the probe beam photons are also obtained analytically. The results of the exact scheme are compared with the corresponding results in the weak field approximation method in full-quantum and semi-classical models

    Multibaseline PolInSAR Using RADARSAT-2 Quad-Pol Data: Improvements in Interferometric Phase Analysis

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    We apply, for the first time, an equal-scattering-mechanism multibaseline optimization technique on quad-pol satellite images of RADARSAT-2 in order to increase the interferometric coherence. The optimized polarimetric channel results in the selection of new pixel candidates for multibaseline differential interferometric synthetic aperture radar applications, which, otherwise, are not recognized in any single-pol channel. In addition, we analyze the individual performance of this algorithm for rural and urban land covers along with the corresponding optimized scattering mechanisms. The optimized coherence improvement with respect to a single HH channel is shown to be correlated with the interferometric spatial and temporal baselines. Finally, we investigate the performance of this technique on the interferometric phase. The optimized interferograms increase the quality of the phase patterns with respect to those phases recovered in a single copolar channel, e.g., the residual orbital ramps of the RADARSAT-2 images.Peer reviewe

    Short-Term Surface Deformation on the Northern Hayward Fault, CA, and Nearby Landslides Using Polarimetric SAR Interferometry (PolInSAR)

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    In this study, we analyze 25 RADARSAT-2 images from ascending and descending geometries to study the creep rate on the Hayward fault and landslide motions near Berkeley, CA. We applied a coherence optimization technique from polarimetric synthetic aperture radar interferometry (PolInSAR) to increase the accuracy of the measurements. We resolve 3–5 mm/year of motion along the Hayward fault, in agreement with earlier creep estimates. We identify a potential motion on secondary fault, northeast and parallel to the Hayward fault, which is creeping at a lower rate of ~1.5 mm/year. In addition, we identify a number of landslides along the hills east of the fault that agree with earlier results from advanced interferometric synthetic aperture radar (SAR) analysis and field investigations. We investigate four particular slope instabilities, one of which was marked as moderately active, and three as highly active, by earlier field investigations. The resolved along-hill slope displacement is estimated at ~23 mm/year. Our results demonstrate that PolInSAR is an effective method to increase the interferometric coherence and provide improved resolution of deformation features associated with natural hazards.This research was funded by the NSERC and Aon Benfield/ICLR IRC in Earthquake Hazard Assessment, an NSERC Discovery Grant, and an Ontario Early Researcher Award. PJG also acknowledges support from a Banting postdoctoral fellowship (Government of Canada).Peer reviewe
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