622 research outputs found

    Real-Time Monitoring of Cellular Cultures with Electrolyte-Gated Carbon Nanotube Transistors

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    Cell-based biosensors constitute a fundamental tool in biotechnology, and their relevance has greatly increased in recent years as a result of a surging demand for reduced animal testing and for high-throughput and cost-effective in vitro screening platforms dedicated to environmental and biomedical diagnostics, drug development and toxicology. In this context, electrochemical/electronic cell-based biosensors represent a promising class of devices that enable long-term and real-time monitoring of cell physiology in a non-invasive and label-free fashion, with a remarkable potential for process automation and parallelization. Common limitations of this class of devices at large include the need for substrate surface modification strategies to ensure cell adhesion and immobilization, limited compatibility with complementary optical cell-probing techniques, and need for frequency-dependent measurements, which rely on elaborated equivalent electrical circuit models for data analysis and interpretation. We hereby demonstrate the monitoring of cell adhesion and detachment through the time-dependent variations in the quasi-static characteristic current curves of a highly stable electrolyte-gated transistor, based on an optically transparent network of printable polymer-wrapped semiconducting carbon-nanotubes

    Gender and Time to Arrival among Ischemic Stroke Patients in the Greater Cincinnati/Northern Kentucky Stroke Study

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    Background Some studies of stroke patients report longer pre-hospital delays in women, but others conflict; studies vary in their inclusion of factors including age and stroke severity. We aimed to investigate the relationship between gender and time to emergency department (ED) arrival and the influence of age and stroke severity on this relationship. Methods Ischemic stroke patients ≥ 20 years old who presented to 15 hospitals within a 5-county region of Greater Cincinnati/Northern Kentucky during 2010 were included. Time from symptom onset to ED arrival and covariates were abstracted by study nurses and reviewed by study physicians. Data were analyzed using logistic regression with time to arrival dichotomized at ≤ 3 hours, in the overall sample and then stratified by NIHSS and age. Results 1991 strokes (55% women) were included. Time to arrival was slightly longer in women (geometric mean 337 minutes [95%CI 307–369] vs. 297 [95%CI 268–329], p =0.05), and 24% of women vs. 27% of men arrived within 3 hours (p=0.15). After adjusting for age, race, NIHSS, living situation, and other covariates, gender was not associated with delayed time to arrival (OR=1.00, 95%CI 0.78–1.28). This did not change across age or NIHSS categories. Conclusions After adjusting for factors including age, NIHSS, and living alone, women and men with ischemic stroke had similar times to arrival. Arrival time is not likely a major contributor to differences in outcome between men and women

    Sex-specific stroke incidence over time in the Greater Cincinnati/Northern Kentucky Stroke Study

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    OBJECTIVE: Recent data suggest stroke incidence is decreasing over time, but it is unknown whether incidence is decreasing in women and men to the same extent. METHODS: Within our population of 1.3 million, all incident strokes among residents ≥20 years old were ascertained at all hospitals during July 1993-June 1994 and calendar years 1999, 2005, and 2010. A sampling scheme was used to ascertain out-of-hospital cases. Sex-specific incidence rates per 100,000 among black and white participants, age- and race-adjusted, were standardized to the 2000 US Census population. Trends over time by sex were compared; a Bonferroni correction was applied for multiple comparisons. RESULTS: Over the 4 study periods, there were 7,710 incident strokes; 57.2% (n = 4,412) were women. Women were older than men (mean ± SE 72.4 ± 0.34 vs 68.2 ± 0.32, p < 0.001). Incidence of all strokes decreased over time in men (263 [confidence interval 246-281] to 192 [179-205], p < 0.001) but not in women (217 [205-230] to 198 [187-210], p = 0.15). Similar sex differences were seen for ischemic stroke (men, 238 [223-257] to 165 [153-177], p < 0.01; women, 193 [181-205] to 173 [162-184], p = 0.09). Incidence of all strokes and of ischemic strokes was similar between women and men in 2010. Incidence of intracerebral hemorrhage and subarachnoid hemorrhage were stable over time in both sexes. CONCLUSIONS: Decreases in stroke incidence over time are driven by a decrease in ischemic stroke in men. Contrary to previous study periods, stroke incidence rates were similar by sex in 2010. Future research is needed to understand why the decrease in ischemic stroke incidence is more pronounced in men

    Sex differences in cardiovascular risk profiles of ischemic stroke patients with diabetes in the Greater Cincinnati/Northern Kentucky Stroke Study

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    Background The aim of the present study was to compare sex-specific associations between cardiovascular risk factors and diabetes mellitus (DM) among patients with acute ischemic stroke (AIS) in the Greater Cincinnati/Northern Kentucky Stroke Study (GCNKSS). Methods The GCNKSS ascertained AIS cases in 2005 and 2010 among adult (age ≥ 20 years) residents of a biracial population of 1.3 million. Past and current stroke risk factors were compared between those with and without DM using Chi-squared tests and multiple logistic regression analysis to examine sex-specific profiles. Results There were 3515 patients with incident AIS; 1919 (55%) were female, 697 (20%) were Black, and 1146 (33%) had DM. Among both women and men with DM, significantly more were obese and had hypertension, high cholesterol, and coronary artery disease (CAD) compared with those without DM. For women with AIS, multivariable sex-specific adjusted analyses revealed that older age was associated with decreased odds of having DM (adjusted odds ratio [aOR] 0.88, 95% confidence interval [CI] 0.80–0.98). For women with CAD, the odds of DM were increased (aOR 1.76, 95% CI 1.33–2.32). Age and CAD were not significant factors in differentiating the profiles of men with and without DM. Conclusions Women with DM had strokes at a younger age, whereas no such age difference existed in men. Compared with men, women with DM were also more likely to have CAD than those without DM, suggesting a sex difference in the association between DM and vascular disease. These findings may suggest a need for more aggressive risk factor management in diabetic women

    Numerical simulation of the temperature distribution of coffee stored in cooled and natural environments.

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    The storage of agricultural products is of great importance in maintaining product quality between harvest and commercialization. The use of numerical and computational techniques, such as the finite element method (FEM) and computational fluid dynamics (CFD), allows the analysis and simulation of systems that involve heat transfer, as is the case of grain storage. A computational model based on these techniques that satisfactorily represents a real system was used to test and to analyze decision alternatives without the need for real experimentation. In this study, we sought to study the behavior of the temperature of a mass of stored mocha coffee beans by using computational techniques, as requested by the private sector. The coffee was stored for 6 months in two types of environments: a cooled environment between 15 and 18 °C by using an air temperature control equipment used for artificial cooling and a natural environment. A computational model was developed to simulate the heat transfer process for both types of storage. In the comparison of the temperature distribution during storage from simulation results and for experimental results, an overall mean relative error of 2.34% was obtained for coffee stored in a natural environment, and that of 5.74% was obtained for coffee stored in a cooled environment

    Coping Responses During the COVID-19 Pandemic: A Cross-Cultural Comparison of Russia, Kyrgyzstan, and Peru

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    Background. The COVID-19 pandemic has subjected people around the world to severe stress, evoking a variety of coping responses. Coping responses can be broadly classified into four strategies: 1) problem-focused coping; 2) emotion-focused coping; 3) socially supported coping; and 4) avoidance. While there is a wide variability of individual coping responses, to some extent they are also culturally specific. Objective. This study aimed to compare the differences in the prevalence and factor structure of coping responses during COVID-19 pandemic in three countries: Russia, Kyrgyzstan, and Peru. Design. The sample included 501 participants from Russia, 456 participants from Kyrgyzstan, and 354 participants from Peru. The mean age of participants was 28 years in Russia (SD = 13.5); 24 years in Kyrgyzstan (SD = 10.0); and 30 years in Peru (SD = 12.3). In Russia and Kyrgyzstan, coping strategies were assessed with an abbreviated Russian adaptation of the COPE (Coping Orientations to Problems Experienced) questionnaire. In Peru, coping responses were assessed using the Spanish version of the Brief COPE questionnaire. The average scores from fifteen COPE scales were used as the input data for linear modelling and factor analysis. Results. The coping scores varied substantially within each country. Differences between countries accounted for 17.7% of the total variability in religious coping; 15.8% in acceptance; 13.9% in mental disengagement; and less than 7% in the other coping strategies. No difference in the prevalence of coping responses was found between Russian and Kyrgyz participants after accounting for age and gender. In all three countries the coping responses were associated with the same four coping domains: problem-focused coping, socially supported coping, avoidance, and emotion-focused coping. Four factors explained up to 44% of the total variation in the COPE scores. Religious coping and mental disengagement were classified into different coping domains in the three countries. Conclusion. The results suggest that during the COVID-19 pandemic, people from different countries apply the full range of coping responses within the four universal coping strategies. Religious coping and mental disengagement differed the most across the countries, suggesting that some coping behaviors can take on different roles within the system of coping responses to stressful events. We attribute these differences to differing cultural and socioeconomic characteristics, and the different measures taken by governments in response to COVID-19

    Evaluation of the behavior of coffee stored in cooled and natural environments.

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    The market value of coffee is strongly influenced by loss of quality, which makes storage one of the main steps in the entire production chain. The finite element method (FEM) and computational fluid dynamics (CFD) are numerical and computational techniques that facilitate the simulation of agricultural product storage systems. Computational modeling satisfactorily represents real experimentation, simplifies decision-making, and reduces costs. This study aimed to analyze mocha coffee storage for 6 months in a cooled environment with temperatures between 15 and 18 °C and in a natural environment. The water content, bulk density, specific heat, thermal conductivity, and thermal diffusivity were determined and colorimetry and sensory analysis were applied to compare initial and final samples of the product after storage. It was found that the water content and specific heat were the only properties that presented significant changes. Through sensory analysis, it was observed that the quality of the coffee was the same for both systems. A computational model was developed to simulate the heat transfer process during storage. The comparison of the simulation results with the experimental results for the temperature distribution in the grain mass showed overall mean relative errors of 2.34% for the natural environment and 5.74% for the cooled environment

    Ajuste y validación de labranza de conservación y rotación de cultivos para un sistema de producción agrícola sostenible del piedemonte metense :informe final

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    Los suelos dedicados a la agricultura en el departamento del Meta han sido sometidos continuamente a un sobre laboreo excesivo, tanto en condiciones secas como de alta humedad, lo que ha conllevado al deterioro de la estructura del suelo y a la formación de capas endurecidas que afectan la emergencia y el establecimiento normal de los cultivos semestrales. Bajo estas condiciones las malezas que se ha adaptado compiten fuertemente por los recursos lumínicos, minerales e hídricos y ocasionan pérdidas grandes en la producción, hasta un 50%, e incrementan los costos de producción necesarios para su control; Estos costos representan normalmente entre el 20 y 30010 de los costos totales
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