Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 189
Filtrar
1.
Bull Environ Contam Toxicol ; 113(1): 1, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38949743

RESUMO

Microplastics (MPs) pollution is a profound problem around the world yet it's study on the effect on zooplankton including copepods are very limited. The study was conducted between January 2021 and January 2022 in the Lower Meghna Estuary to investigate MPs ingestion in two different family of copepod: Calanoid and Cyclopoid. A method of acid digestion along with Scanning Electron Microscope (SEM) was used to identify MPs ingested by copepods from the conducted area. However, three types of MPs namely fiber, fragment and foam were extracted from this copepod biomass. Fibers represent highest (> 50%) of the ingested MPs from both group of copepod that exceed fragments and foams in all sampling stations. The overall ingestion rate of Calanoid was found higher (0.084 ± 0.002 particles/individual) compared to the Cyclopoid group (0.077 ± 0.001 particles/individual). The results of the study have effectively illustrated that copepod, obtained from multiple sampling sites within the Lower Meghna Estuary, display a propensity to ingest MPs and subsequently endangering the food security of seafood industry.


Assuntos
Copépodes , Monitoramento Ambiental , Estuários , Microplásticos , Poluentes Químicos da Água , Animais , Microplásticos/análise , Poluentes Químicos da Água/análise , Bangladesh , Ingestão de Alimentos
2.
Opt Lett ; 48(8): 2162-2165, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-37058667

RESUMO

Due to their sub-millimeter spatial resolution, ink-based additive manufacturing tools are typically considered less attractive than nanophotonics. Among these tools, precision micro-dispensers with sub-nanoliter volumetric control offer the finest spatial resolution: down to 50 µm. Within a sub-second, a flawless, surface-tension-driven spherical shape of the dielectric dot is formed as a self-assembled µlens. When combined with dispersive nanophotonic structures defined on a silicon-on-insulator substrate, we show that the dispensed dielectric µlenses [numerical aperture (NA) = 0.36] engineer the angular field distribution of vertically coupled nanostructures. The µlenses improve the angular tolerance for the input and reduces the angular spread of the output beam in the far field. The micro-dispenser is fast, scalable, and back-end-of-line compatible, allowing geometric-offset-caused efficiency reductions and center wavelength drift to be easily fixed. The design concept is experimentally verified by comparing several exemplary grating couplers with and without a µlens on top. A difference of less than 1 dB between incident angles of 7° and 14° is observed in the index-matched µlens, while the reference grating coupler shows around 5 dB contrast.

3.
Circulation ; 143(16): 1571-1583, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33650435

RESUMO

BACKGROUND: There are limited data on the unique cardiovascular disease (CVD), non-CVD, and mortality risks of primary prevention individuals with very high coronary artery calcium (CAC; ≥1000), especially compared with rates observed in secondary prevention populations. METHODS: Our study population consisted of 6814 ethnically diverse individuals 45 to 84 years of age who were free of known CVD from MESA (Multi-Ethnic Study of Atherosclerosis), a prospective, observational, community-based cohort. Mean follow-up time was 13.6±4.4 years. Hazard ratios of CAC ≥1000 were compared with both CAC 0 and CAC 400 to 999 for CVD, non-CVD, and mortality outcomes with the use of Cox proportional hazards regression adjusted for age, sex, and traditional risk factors. Using a sex-adjusted logarithmic model, we calculated event rates in MESA as a function of CAC and compared them with those observed in the placebo group of stable secondary prevention patients in the FOURIER clinical trial (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Subjects With Elevated Risk). RESULTS: Compared with CAC 400 to 999, those with CAC ≥1000 (n=257) had a greater mean number of coronary vessels with CAC (3.4±0.5), greater total area of CAC (586.5±275.2 mm2), similar CAC density, and more extensive extracoronary calcification. After full adjustment, CAC ≥1000 demonstrated a 4.71- (3.63-6.11), 7.57- (5.50-10.42), 4.86-(3.32-7.11), and 1.94-fold (1.57-2.41) increased risk for all CVD events, all coronary heart disease events, hard coronary heart disease events, and all-cause mortality, respectively, compared with CAC 0 and a 1.65- (1.25-2.16), 1.66- (1.22-2.25), 1.51- (1.03-2.23), and 1.34-fold (1.05-1.71) increased risk compared with CAC 400 to 999. With increasing CAC, hazard ratios increased for all event types, with no apparent upper CAC threshold. CAC ≥1000 was associated with a 1.95- (1.57-2.41) and 1.43-fold (1.12-1.83) increased risk for a first non-CVD event compared with CAC 0 and CAC 400 to 999, respectively. CAC 1000 corresponded to an annualized 3-point major adverse cardiovascular event rate of 3.4 per 100 person-years, similar to that of the total FOURIER population (3.3) and higher than those of the lower-risk FOURIER subgroups. CONCLUSIONS: Individuals with very high CAC (≥1000) are a unique population at substantially higher risk for CVD events, non-CVD outcomes, and mortality than those with lower CAC, with 3-point major adverse cardiovascular event rates similar to those of a stable treated secondary prevention population. Future guidelines should consider a less distinct stratification algorithm between primary and secondary prevention patients in guiding aggressive preventive pharmacotherapy.


Assuntos
Cálcio/efeitos adversos , Doenças Cardiovasculares/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Doenças Cardiovasculares/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Sobrevida , Resultado do Tratamento
4.
Sensors (Basel) ; 22(18)2022 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-36146397

RESUMO

High-dynamic-range (HDR) image reconstruction methods are designed to fuse multiple Low-dynamic-range (LDR) images captured with different exposure values into a single HDR image. Recent CNN-based methods mostly perform local attention- or alignment-based fusion of multiple LDR images to create HDR contents. Depending on a single attention mechanism or alignment causes failure in compensating ghosting artifacts, which can arise in the synthesized HDR images due to the motion of objects or camera movement across different LDR image inputs. In this study, we propose a multi-scale attention-guided non-local network called MSANLnet for efficient HDR image reconstruction. To mitigate the ghosting artifacts, the proposed MSANLnet performs implicit alignment of LDR image features with multi-scale spatial attention modules and then reconstructs pixel intensity values using long-range dependencies through non-local means-based fusion. These modules adaptively select useful information that is not damaged by an object's movement or unfavorable lighting conditions for image pixel fusion. Quantitative evaluations against several current state-of-the-art methods show that the proposed approach achieves higher performance than the existing methods. Moreover, comparative visual results show the effectiveness of the proposed method in restoring saturated information from original input images and mitigating ghosting artifacts caused by large movement of objects. Ablation studies show the effectiveness of the proposed method, architectural choices, and modules for efficient HDR reconstruction.

5.
Prev Med ; 153: 106800, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34520787

RESUMO

The e-cigarette or vaping product-use-associated lung injury outbreak in the United States has raised concerns about the potential health effects of cannabis vaping, a method of cannabis use that is becoming increasingly popular. We used 2017-2019 Behavioral Risk Factor Surveillance System data to estimate yearly prevalence and trends of past-30-day cannabis use and vaping among US adults. We used multivariable logistic regression to evaluate the associations of cannabis vaping with high-risk behaviors, asthma, and other respiratory symptoms. Our sample size was 160,209 (53,945-2017; 55,475-2018; and 50,789-2019). Past-30-day cannabis use prevalence increased from 10.0% (95% CI, 9.4%-10.7%) in 2017 to 13.4% (12.8%-12.0%) in 2019. Similarly, past-30-day cannabis vaping prevalence increased from 1.0% (0.8%-1.2%) to 2.0% (1.7%-2.2%) over the same period, with the greatest increase, 1.2% to 3.9%, observed among young adults (18-24 years). Individuals who vaped cannabis were more likely to concurrently vape nicotine. Cannabis vaping was associated with increased odds of heavy alcohol use (aOR, 1.95; 95% CI, 1.45-2.63), binge drinking (aOR, 2.82; 95% CI, 2.25-3.54), and other high-risk behaviors (aOR, 2.47; 95% CI, 1.89-3.24). In analyses adjusting for sociodemographic characteristics and body mass index, cannabis vaping was not associated with asthma (aOR, 1.03; 95% CI, 0.64-1.64) or other respiratory symptoms (aOR, 1.08; 95% CI, 0.44-2.63). Adjusting for nicotine vaping did not substantively alter these associations. The prevalence of past-30-day cannabis vaping has increased, particularly among young adults, and was associated with high-risk behaviors. Although there was no association between cannabis vaping and asthma or other respiratory symptoms, the increasing trends of cannabis vaping, particularly among young adults, raise concern and underscore the need for continued surveillance.


Assuntos
Cannabis , Sistemas Eletrônicos de Liberação de Nicotina , Vaping , Cannabis/efeitos adversos , Humanos , Prevalência , Assunção de Riscos , Estados Unidos/epidemiologia , Vaping/efeitos adversos , Vaping/epidemiologia , Adulto Jovem
6.
Indoor Air ; 31(6): 1815-1825, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34121237

RESUMO

The role of airborne particles in the spread of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is well explored. The novel coronavirus can survive in aerosol for extended periods, and its interaction with other viral communities can cause additional virulence and infectivity. This baseline study reports concentrations of SARS-CoV-2, other respiratory viruses, and pathogenic bacteria in the indoor air from three major hospitals (Sheikh Jaber, Mubarak Al-Kabeer, and Al-Amiri) in Kuwait dealing with coronavirus disease 2019 (COVID-19) patients. The indoor aerosol samples showed 12-99 copies of SARS-CoV-2 per m3 of air. Two non-SARS-coronavirus (strain HKU1 and NL63), respiratory syncytial virus (RSV), and human bocavirus, human rhinoviruses, Influenza B (FluB), and human enteroviruses were also detected in COVID-positive areas of Mubarak Al Kabeer hospital (MKH). Pathogenic bacteria such as Mycoplasma pneumonia, Streptococcus pneumonia and, Haemophilus influenza were also found in the hospital aerosols. Our results suggest that the existing interventions such as social distancing, use of masks, hand hygiene, surface sanitization, and avoidance of crowded indoor spaces are adequate to prevent the spread of SARS-CoV-2 in enclosed areas. However, increased ventilation can significantly reduce the concentration of SARS-CoV-2 in indoor aerosols. The synergistic or inhibitory effects of other respiratory pathogens in the spread, severity, and complexity of SARS-CoV-2 need further investigation.


Assuntos
Aerossóis , Poluição do Ar em Ambientes Fechados , Bactérias , SARS-CoV-2 , Vírus , Bactérias/isolamento & purificação , COVID-19 , Hospitais , Humanos , Kuweit , SARS-CoV-2/isolamento & purificação , Vírus/isolamento & purificação
7.
Prev Med ; 139: 106175, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32593733

RESUMO

Use of substances other than nicotine in e-cigarettes, especially marijuana, is becoming increasingly popular in the US. However, population-representative data on such poly-use (nicotine and marijuana) remains limited. We therefore conducted a cross-sectional logistic regression analysis of the 2018 Behavioral Risk Factor Surveillance System among 16 US states/territories with data on past 30-day marijuana use to describe the emerging dual nicotine and marijuana vaping population. We additionally examined trends in marijuana use, including marijuana vaping, from 2016 to 2018. Of the 131,807 participants studied, 3068 were current e-cigarette users, among whom 7.1% also vaped marijuana. Prevalence of nicotine-predominant, dual nicotine marijuana, and marijuana-predominant vaping was 3.36%, 0.38% and 1.09%, respectively. Compared to nicotine-predominant vapers, dual and marijuana-predominant vapers were older, had greater proportions of non-Whites, particularly Hispanics, and less likely to be current smokers (nicotine-predominant vs dual vs marijuana-predominant vaping: current tobacco use 44.7 vs 23.7 vs 11.1%). Proportion of dual vapers among current e-cigarette users was 8.6%, 2.6% and 7.1% for 2016, 2017 and 2018, respectively. Prevalence of marijuana use increased from 8.97% (2016) to 13.1% (2018) while no clear trend was observed for marijuana vaping. Dual nicotine and marijuana vaping is prevalent in the US, and compared to predominantly nicotine vapers such users have higher mean ages, and are more likely to be Blacks, Hispanics, and never cigarette smokers. Marijuana use overall increased from 2016 to 2018. Dual vapers represent a large and important emerging population that will require dedicated study of health effects and tailored regulatory strategies.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Uso da Maconha , Adulto , Sistema de Vigilância de Fator de Risco Comportamental , Estudos Transversais , Humanos , Nicotina , Prevalência
8.
Curr Cardiol Rep ; 22(12): 155, 2020 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-33037523

RESUMO

PURPOSE OF REVIEW: The increasing popularity and prevalence of electronic cigarettes (e-cigarettes) use in the USA necessitates careful evaluation of their proposed benefits and potential public health harms. This report provides a detailed review of current scientific evidence on potential benefits and health risks associated with e-cigarette use. RECENT FINDINGS: E-cigarettes were introduced as a less harmful alternative to combustible cigarette smoking. However, evidence on their use as effective and safe smoking cessation aids remains inconclusive. Their rapid uptake among tobacco-naive individuals can lead to nicotine addiction and subsequent cigarette smoking. Although e-cigarettes appear to be relatively safer than combustible cigarettes, they expose users to known harmful constituents whose long-term health risks remain unknown. While e-cigarettes have the potential to aid in cessation of cigarette smoking when used as part of a structured cessation program, use among tobacco-naive youth and long-term dual use with combustible cigarettes should be strongly discouraged due to excess risk with dual use.


Assuntos
Fumar Cigarros , Sistemas Eletrônicos de Liberação de Nicotina , Abandono do Hábito de Fumar , Vaping , Adolescente , Humanos , Saúde Pública , Vaping/efeitos adversos
9.
Sensors (Basel) ; 20(11)2020 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-32512949

RESUMO

Deep-learning-based image inpainting methods have shown significant promise in both rectangular and irregular holes. However, the inpainting of irregular holes presents numerous challenges owing to uncertainties in their shapes and locations. When depending solely on convolutional neural network (CNN) or adversarial supervision, plausible inpainting results cannot be guaranteed because irregular holes need attention-based guidance for retrieving information for content generation. In this paper, we propose two new attention mechanisms, namely a mask pruning-based global attention module and a global and local attention module to obtain global dependency information and the local similarity information among the features for refined results. The proposed method is evaluated using state-of-the-art methods, and the experimental results show that our method outperforms the existing methods in both quantitative and qualitative measures.

10.
J Phys Chem A ; 123(34): 7518-7527, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31365257

RESUMO

Soil water repellency (SWR) is an extensively occurring phenomenon on natural and agricultural soils with a severe impact on soil water relations and thus crop yields and ecosystem productivity. It is caused by long chain amphiphilic compounds that originate from plant cuticular waxes. However, the severity of SWR varies with soil physical properties and the concentration of the compounds closely associated with producing hydrophobic coatings on soil surfaces. The induction of SWR by hexadecane, isopropyl tetradecanoate, and palmitic acid (PA), as pure (individual) coatings and as coatings composed of binary mixtures, was investigated by applying a range of loadings on acid-washed sand (AWS) (300-500 µm diameter) and AWS with 5% kaolinite. Molarity of ethanol droplet (MED) tests were conducted to assess the severity of SWR. Palmitic acid was very effective at inducing SWR at loadings of >0.5 × 10-6 mol g-1. Hexadecane and isopropyl tetradecanoate had no effect on SWR when applied as single component coatings. However, when hexadecane was combined with palmitic acid, it enhanced the SWR effect of palmitic acid. In comparison, isopropyl tetradecanoate was found to partially mitigate the SWR caused by palmitic acid. The experimental measurements of SWR were complemented by fully atomistic molecular dynamics simulations that suggested variations of SWR could be explained through molecular level interactions, packing on different soil mineral surfaces and the surface characteristics of the mineral surfaces. In addition, H-donor interactions of PA were found to be instrumental in intermolecular and surface interactions. Furthermore, cohesion and packing of hydrocarbon chains were found to be important parameters favoring surface adhesion, which in turn led to the formation of hydrophobic molecular coatings. The finding that ester derivatives of long chain fatty acids do not induce water repellency suggests that the introduction of chemical or biological processes that promote esterification of fatty acids could be a mechanism for reducing soil water repellency in agricultural soils.

11.
BMC Pulm Med ; 19(1): 180, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31619218

RESUMO

BACKGROUND: E-cigarette use prevalence has grown rapidly in the US. Despite the popularity of these products, few acute exposure toxicity studies exist, and studies on long-term pulmonary health effects are limited. E-cigarette users who are never combustible cigarette smokers (sole users) constitute a unique group of young adults that may be at increased risk of bronchial hyperreactivity and development of asthma. Given the public health concern about the potential pulmonary health effects of sole e-cigarette use, we aimed to examine the association between e-cigarette use and asthma among never combustible cigarette smokers. METHODS: We pooled 2016 and 2017 data of the Behavioral Risk Factor Surveillance System (BRFSS), a large, cross-sectional telephone survey of adults aged 18 years and older in the U.S. We included 402,822 participants without any history of combustible cigarette smoking (defined as lifetime smoking < 100 cigarettes) and with complete self-reported information on key variables. Current e-cigarette use, further classified as daily or occasional use, was the primary exposure. The main outcome, asthma, was defined as self-reported history of asthma. We assess the relationship of sole e-cigarette use with asthma using multivariable logistic regression adjusting for age, sex, race, income, level of education and body mass index. RESULTS: Of 402,822 never combustible cigarette smokers, there were 3103 (0.8%) current e-cigarette users and 34,074 (8.5%) with asthma. The median age group of current e-cigarette users was 18-24 years. Current e-cigarette use was associated with 39% higher odds of self-reported asthma compared to never e-cigarette users (Odds Ratio [OR], 1.39; 95% confidence interval: 1.15, 1.68). There was a graded increased odds of having asthma with increase of e-cigarette use intensity. The odds ratio of self-reported asthma increased from 1.31 (95% confidence interval: 1.05, 1.62) in occasional users to 1.73 (95% confidence interval: 1.21, 2.48) in daily e-cigarette users, compared to never e-cigarette users. CONCLUSION: Our findings from a large, nationally representative survey suggest increased odds of asthma among never combustible smoking e-cigarette users. This may have potential public health implications, providing a strong rationale to support future longitudinal studies of pulmonary health in young e-cigarette-using adults.


Assuntos
Asma , Fumar Cigarros , Sistemas Eletrônicos de Liberação de Nicotina/estatística & dados numéricos , não Fumantes/estatística & dados numéricos , Asma/diagnóstico , Asma/epidemiologia , Sistema de Vigilância de Fator de Risco Comportamental , Fumar Cigarros/epidemiologia , Fumar Cigarros/fisiopatologia , Estudos Transversais , Feminino , Humanos , Masculino , Prevalência , Autorrelato/estatística & dados numéricos , Adulto Jovem
12.
Ann Intern Med ; 169(7): 429-438, 2018 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-30167658

RESUMO

Background: Contemporary data on the prevalence of e-cigarette use in the United States are limited. Objective: To report the prevalence and distribution of current e-cigarette use among U.S. adults in 2016. Design: Cross-sectional. Setting: Behavioral Risk Factor Surveillance System, 2016. Participants: Adults aged 18 years and older. Measurements: Prevalence of current e-cigarette use by sociodemographic groups, comorbid medical conditions, and states of residence. Results: Of participants with information on e-cigarette use (n = 466 842), 15 240 were current e-cigarette users, representing a prevalence of 4.5%, which corresponds to 10.8 million adult e-cigarette users in the United States. Of the e-cigarette users, 15% were never-cigarette smokers. The prevalence of current e-cigarette use was highest among persons aged 18 to 24 years (9.2% [95% CI, 8.6% to 9.8%]), translating to approximately 2.8 million users in this age range. More than half the current e-cigarette users (51.2%) were younger than 35 years. In addition, the age-standardized prevalence of e-cigarette use was high among men; lesbian, gay, bisexual, and transgender (LGBT) persons; current combustible cigarette smokers; and those with chronic health conditions. The prevalence of e-cigarette use varied widely among states, with estimates ranging from 3.1% (CI, 2.3% to 4.1%) in South Dakota to 7.0% (CI, 6.0% to 8.2%) in Oklahoma. Limitation: Data were self-reported, and no biochemical confirmation of tobacco use was available. Conclusion: E-cigarette use is common, especially in younger adults, LGBT persons, current cigarette smokers, and persons with comorbid conditions. The prevalence of use differs across states. These contemporary estimates may inform researchers, health care policymakers, and tobacco regulators about demographic and geographic distributions of e-cigarette use. Primary Funding Source: American Heart Association Tobacco Regulation and Addiction Center, which is funded by the U.S. Food and Drug Administration and National Heart, Lung, and Blood Institute.


Assuntos
Vaping/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Sistema de Vigilância de Fator de Risco Comportamental , Estudos Transversais , Sistemas Eletrônicos de Liberação de Nicotina/estatística & dados numéricos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Fatores Sexuais , Fatores Socioeconômicos , Estados Unidos/epidemiologia , Adulto Jovem
13.
Clin Infect Dis ; 67(10): 1507-1514, 2018 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-29668900

RESUMO

Background: Knowledge of risk factors for symptomatic human coronavirus (HCoV) infections in children in community settings is limited. We estimated the disease burden and impact of birth-related, maternal, household, and seasonal factors on HCoV infections among children from birth to 6 months old in rural Nepal. Methods: Prospective, active, weekly surveillance for acute respiratory infections (ARIs) was conducted in infants over a period of 3 years during 2 consecutive, population-based randomized trials of maternal influenza immunization. Midnasal swabs were collected for acute respiratory symptoms and tested for HCoV and other viruses by reverse-transcription polymerase chain reaction. Association between HCoV incidence and potential risk factors was modeled using Poisson regression. Results: Overall, 282 of 3505 (8%) infants experienced an HCoV ARI within the first 6 months of life. HCoV incidence overall was 255.6 (95% confidence interval [CI], 227.3-286.5) per 1000 person-years, and was more than twice as high among nonneonates than among neonates (incidence rate ratio [IRR], 2.53; 95% CI, 1.52-4.21). HCoV ARI incidence was also positively associated with the number of children <5 years of age per room in a household (IRR, 1.13; 95% CI, 1.01-1.28). Of the 296 HCoV infections detected, 46% were coinfections with other respiratory viruses. While HCoVs were detected throughout the study period, seasonal variation was also observed, with incidence peaking in 2 winters (December-February) and 1 autumn (September-November). Conclusions: HCoV is associated with a substantial proportion of illnesses among young infants in rural Nepal. There is an increased risk of HCoV infection beyond the first month of life.


Assuntos
Infecções por Coronavirus/epidemiologia , Efeitos Psicossociais da Doença , Infecções Respiratórias/epidemiologia , População Rural , Adulto , Pré-Escolar , Coinfecção/epidemiologia , Coinfecção/virologia , Coronavirus/genética , Coronavirus/isolamento & purificação , Monitoramento Epidemiológico , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Nepal/epidemiologia , Gravidez , Gestantes , Estudos Prospectivos , Análise de Regressão , Infecções Respiratórias/virologia , Fatores de Risco , Estações do Ano , Adulto Jovem
14.
Langmuir ; 33(44): 12777-12784, 2017 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-29022718

RESUMO

Controllable synthesis of organic thin film materials on solid surfaces is a challenging issue in the research field of surface science, as it is affected by several physical parameters. In this work, we demonstrated a solution-based molecular layer deposition (MLD) approach to prepare porphyrin-based covalent organic molecular networks on a 3-aminopropyl trimethoxysilane (APTMS) modified substrate surface using the urea coupling reaction between 1,4-phenylene diisocyanate (1,4-PDI) and 5,10,15,20-tetrakis-(4-aminophenyl) porphyrin (H2TAPP) at room temperature (22 ± 2 °C). Multilayer growth was investigated under different relative humidity (RH) conditions of the reaction chamber. Sequential molecular growth at low relative humidity (≤10% RH) was observed using UV-vis absorption spectroscopy and atomic force microscopy (AFM). The high-RH condition shows limited film growth. Infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) revealed the polyurea bond formation in sequential multilayer thin films, demonstrating that stepwise multilayer film growth was achieved using the urea coupling reaction.

16.
Osteoarthritis Cartilage ; 24(11): 1989-1998, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27364595

RESUMO

OBJECTIVES: Cartilage is a highly mechano-responsive tissue. Chondrocytes undergo a series of complex changes, including proliferation and metabolic alteration as the target of external biomechanical and biochemical stimuli. IL-1ß is known to regulate chondrocyte metabolism and plays an important role in the pathogenesis of osteoarthritis (OA). The objective of this study was to employ low-intensity pulsed ultrasound (LIPUS) as a localized mechanical stimulus and assess its effects on chondrocyte migration, proliferation, metabolism, and differentiation, as well as its ability to suppress IL-1ß mediated catabolism in cartilage. METHODS: Human cartilage explants and chondrocytes were stimulated by LIPUS in the presence and absence of IL-1ß to asses cartilage degradation, chondrocytes metabolism, migration, and proliferation. Western blot analyses were conducted to study IL-1ß the associated NFκB pathway in chondrocytes. RESULTS: LIPUS stimulation increased the proteoglycan content in human cartilage explants and inhibited IL-1ß induced loss of proteoglycans. LIPUS stimulation increased rates of chondrocyte migration and proliferation, and promoted chondrogenesis in mesenchymal stem cells (MSC). Further, LIPUS suppressed IL-1ß induced activation of phosphorylation of NFκB-p65 and IĸBα leading to reduced expression of MMP13 and ADAMT5 in chondrocytes. CONCLUSIONS: Collectively, these data demonstrate the potential therapeutic effects of LIPUS in preventing cartilage degradation and treating OA via a mechanical stimulation that inhibits the catabolic action of IL-1ß and stimulates chondrocyte migration, proliferation, and differentiation.


Assuntos
Ondas Ultrassônicas , Cartilagem Articular , Células Cultivadas , Condrócitos , Humanos , Interleucina-1beta , Osteoartrite
17.
BMC Complement Altern Med ; 16(1): 398, 2016 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-27769218

RESUMO

BACKGROUND: This plant is very popular ingredient of local made drinks during hot summer. After drinking this drink people feels fresh, relaxed and can enjoy sound sleep. Present study was aimed to assess the sedative properties of a plant Sterculia villosa leaves. Therefore, we tried to find out the methanolic extract from the leaves of Sterculia villosa leaves having any sedative activity or not. METHODS: The extract were subjected to various in vivo methods like hole cross test, open field test, elevated plus-maze (EPM) test, thiopental sodium induced sleeping time test. Diazepam was used as the standard drug. RESULTS: From the study, it is clear that the extract has excellent CNS depressant activity by reducing locomotors activity of mice in every cases of hole cross test, open field test, elevated plus-maze (EPM) test compared to the standard diazepam. In addition, the extract prolong the sleeping time (230 min) with quick onset of action (9 min) in contrast to the standard and control group. CONCLUSIONS: From the present study it can be conclude that the extract posses significant a sedative property that may lead to new drug development and further investigation is necessary to understand the underlying mechanisms and to isolate the active principles.


Assuntos
Comportamento Animal/efeitos dos fármacos , Hipnóticos e Sedativos/farmacologia , Extratos Vegetais/farmacologia , Folhas de Planta/química , Sterculia/química , Animais , Hipnóticos e Sedativos/química , Locomoção/efeitos dos fármacos , Aprendizagem em Labirinto/efeitos dos fármacos , Metanol , Camundongos , Extratos Vegetais/química
19.
Mol Pharm ; 12(1): 179-93, 2015 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-25389571

RESUMO

Better predictive ability of salt and buffer effects on protein-protein interactions requires separating out contributions due to ionic screening, protein charge neutralization by ion binding, and salting-in(out) behavior. We have carried out a systematic study by measuring protein-protein interactions for a monoclonal antibody over an ionic strength range of 25 to 525 mM at 4 pH values (5, 6.5, 8, and 9) in solutions containing sodium chloride, calcium chloride, sodium sulfate, or sodium thiocyante. The salt ions are chosen so as to represent a range of affinities for protein charged and noncharged groups. The results are compared to effects of various buffers including acetate, citrate, phosphate, histidine, succinate, or tris. In low ionic strength solutions, anion binding affinity is reflected by the ability to reduce protein-protein repulsion, which follows the order thiocyanate > sulfate > chloride. The sulfate specific effect is screened at the same ionic strength required to screen the pH dependence of protein-protein interactions indicating sulfate binding only neutralizes protein charged groups. Thiocyanate specific effects occur over a larger ionic strength range reflecting adsorption to charged and noncharged regions of the protein. The latter leads to salting-in behavior and, at low pH, a nonmonotonic interaction profile with respect to sodium thiocyanate concentration. The effects of thiocyanate can not be rationalized in terms of only neutralizing double layer forces indicating the presence of an additional short-ranged protein-protein attraction at moderate ionic strength. Conversely, buffer specific effects can be explained through a charge neutralization mechanism, where buffers with greater valency are more effective at reducing double layer forces at low pH. Citrate binding at pH 6.5 leads to protein charge inversion and the formation of attractive electrostatic interactions. Throughout the report, we highlight similarities in the measured protein-protein interaction profiles with previous studies of globular proteins and of antibodies providing evidence that the behavior will be common to other protein systems.


Assuntos
Anticorpos Monoclonais/química , Íons , Mapeamento de Interação de Proteínas , Soluções Tampão , Cloreto de Cálcio , Cloretos/química , Relação Dose-Resposta a Droga , Concentração de Íons de Hidrogênio , Cinética , Luz , Sais/química , Espalhamento de Radiação , Cloreto de Sódio/química , Sulfatos/química , Tiocianatos/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA