40 research outputs found

    Band-edge Bilayer Plasmonic Nanostructure for Surface Enhanced Raman Spectroscopy

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    Spectroscopic analysis of large biomolecules is critical in a number of applications, including medical diagnostics and label-free biosensing. Recently, it has been shown that Raman spectroscopy of proteins can be used to diagnose some diseases, including a few types of cancer. These experiments have however been performed using traditional Raman spectroscopy and the development of the Surface enhanced Raman spectroscopy (SERS) assays suitable for large biomolecules could lead to a substantial decrease in the amount of specimen necessary for these experiments. We present a new method to achieve high local field enhancement in surface enhanced Raman spectroscopy through the simultaneous adjustment of the lattice plasmons and localized surface plasmon polaritons, in a periodic bilayer nanoantenna array resulting in a high enhancement factor over the sensing area, with relatively high uniformity. The proposed plasmonic nanostructure is comprised of two interacting nanoantenna layers, providing a sharp band-edge lattice plasmon mode and a wide-band localized surface plasmon for the separate enhancement of the pump and emitted Raman signals. We demonstrate the application of the proposed nanostructure for the spectral analysis of large biomolecules by binding a protein (streptavidin) selectively on the hot-spots between the two stacked layers, using a low concentration solution (100 nM) and we successfully acquire its SERS spectrum

    Numerical simulation of a multi-inlet microfluidic device for biosensing purposes in osteoporosis management

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    Objectives In this paper, the effect of the position of the inlet and outlet microchannels on the flow profile and the geometry of the recognition chamber for sample pre-treatment in an electrochemical biosensor to be used in osteoporosis management were investigated. Methods All numerical computation presented in this work were performed using COMSOL Multiphysics and Fluent. Simulation was performed for a three-dimensional, incompressible Navier-Stokes flow and so explicit biphasic volume of fluid (VOF) equations were used. Results In the designed microfluidic system, a pressure-driven laminar flow with no-slip boundary condition was responsible for fluid actuation through microchannels in a reproducible approach. Based on the simulation results, the number of outlets was increased and the angel through which the inlets and outlets were attached to the microchamber was changed so that the dead volume would be eliminated and the fluid flow trajectory, the velocity field and pressure were evenly distributed across the chamber. The Re number in the inlets was equal to 4.41, suggesting a laminar flow at this site. Conclusion The simulation results along with the fact that the design change was tested using laser ablated tape and a color dye at different steps provided the researchers with the opportunity to study the changes in a fast and accurate but cheap method. The absence of backflow helps with the cross-talk concern in the channels and the lack of bubbles and complete coverage of the chamber helps with a better surface modification and thus better sensing performance

    Using Adaptive Pole Placement Control Strategy for Active Steering Safety System

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    This paper studies the design of an adaptive control strategy to tune an active steering system for better drivability and maneuverability. In the first step, adaptive control strategy is applied to estimate the uncertain parameters on-line (e.g. cornering stiffness), then the estimated parameters are fed into the pole placement controller to generate corrective feedback gain to improve the steering system dynamic's characteristics. The simulations are evaluated for three types of road conditions (dry, wet, and icy), and the performance of the adaptive pole placement control (APPC) are compared with pole placement control (PPC) and a passive system. The results show that the APPC strategy significantly improves the yaw rate and side slip angle of a bicycle plant model

    Suicidal Ideation in Patients With Gender Identity Disorder in Western Iran From March 2019 to March 2020

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    Background: In recent years, the number of patients with gender identity disorder (GID) has rapidly increased. These people are at risk of adverse life events that influence their health and wellbeing. Research studies have also shown a significant rate of suicide in these individuals. This study aims to determine the prevalence of suicidal ideation in patients with GID referred to Legal Medicine Office in Ilam Province.Methods: In study sample comprised 21 patients without psychiatric comorbidity visited the Legal Medicine Office in Ilam Province for confirmation of transsexuals from March 2019 to March 2020. GID disorder was diagnosed through a GIDYQ (A-A) questionnaire and clinical interview. The Beck scale for suicide ideation was used to clarify and measure the intensity of attitudes, behaviors, and planning for a suicide attempt.Results: In 21 patients with GID, the average score for suicide ideation was 11.6. The average age of patients was 19 years, and all of them were single. In this sample, 19.1% had low risks, 71.5% high risks, 9.5% had very high-risk suicide ideation. Linear regression analysis showed that higher education and higher age were risk factors for suicide ideation in patients with GID.Conclusion: The high rate of suicidal ideation in patients with gender identity disorder makes it essential to pay attention to their mental health. It should be noted that suicidal thoughts can be a basis for suicide attempts

    Sub-microsecond thermal reconfiguration of silicon photonic devices

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    © 2009 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.DOI: 10.1109/LEOS.2009.5343159Using the experimental data we show the possibility of sub-microsecond reconfiguration of silicon photonics microresonators through pulse shaping of micro-heater excitation. Also, a novel heater structure based on small microdisk resonators with sub-hundred-nanosecond reconfiguration speed is proposed and investigated theoretically

    Sustained GHz oscillations in ultra-high Q silicon microresonators

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    © 2009 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.DOI: 10.1109/LEOS.2009.5343287We report the experimental observation of long-sustained GHz electronic oscillations resulting from coupled electron-photon dynamics in ultra-high-Q Si microdisk resonators with CW pumping. Theoretical analysis identifies conditions for steady-state GHz oscillations while suppressing thermal oscillations

    Post-discharge health assessment in survivors of coronavirus disease: a time-point analysis of a prospective cohort study

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    © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2023, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law. This article is made available via the PMC Open Access Subset for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.PURPOSE: The objective of this study was to quantitatively evaluate psychological and quality of life-related complications at three months following discharge in hospitalized coronavirus disease 2019 (COVID-19) patients during the pandemic in Iran. METHODS: In this time-point analysis of prospective cohort study data, adult patients hospitalized with symptoms suggestive of COVID-19 were enrolled. Patients were stratifed in analyses based on severity. The primary outcomes consisted of psychological problems and pulmonary function tests (PFTs) in the three months following discharge, with Health-related quality of life (HRQoL) as the secondary outcome. Exploratory predictors were determined for both primary and secondary outcomes. Results 283 out of 900 (30%) eligible patients were accessible for the follow-up assessment and included in the study. The mean age was 53.65±13.43 years, with 68% experiencing a severe disease course. At the time of the fnal follow-up, participants still reported persistent symptoms, among which fatigue, shortness of breath, and cough were the most common. Based on the regression-adjusted analysis, lower levels of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) ratio was associated with higher levels of depression (standardized ß=- 0.161 (SE=0.042), P=0.017) and stress levels (standardized ß=- 0.110 (SE=0.047), P=0.015). Furthermore, higher levels of anti-SARS-CoV-2 immunoglobulinM (IgM) were associated with signifcantly lower levels of depression (standardized ß=- 0.139 (SE=0.135), P=0.031). CONCLUSIONS: There is an association between lung damage during COVID-19 and the reduction of pulmonary function for up to three months from acute infection in hospitalized patients. Varying degrees of anxiety, depression, stress, and low HRQoL frequently occur in patients with COVID-19. More severe lung damage and lower COVID-19 antibodies were associated with lower levels of psychological health.Isfahan University of Medical Sciences, IR.MUI.MED.REC.1399.517, Ramin SamiPeer ReviewedPostprint (published version

    Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

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    Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic
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