Over-overlapped loop arrays: A numerical study.
Ontology highlight
ABSTRACT:
SUBMITTER: Lu M
PROVIDER: S-EPMC7443860 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:This paper presents a numerical study of DC-biased AC-electrokinetic (DC-biased ACEK) flow over a pair of symmetrical electrodes. The flow mechanism is based on a transverse conductivity gradient created through incipient Faradaic reactions occurring at the electrodes when a DC-bias is applied. The DC biased AC electric field acting on this gradient generates a fluid flow in the form of vortexes. To understand more in depth the DC-biased ACEK flow mechanism, a phenomenological model is developed to study the effects of voltage, conductivity ratio, channel width, depth, and aspect ratio on the induced flow characteristics. It was found that flow velocity on the order of mm/s can be produced at higher voltage and conductivity ratio. Such rapid flow velocity is one of the highest reported in microsystems technology using electrokinetics.
| S-EPMC3365336 | biostudies-other
Project description:The numerical approximation of definite integrals, or quadrature, often involves the construction of an interpolant of the integrand and its subsequent integration. In the case of one dimension it is natural to rely on polynomial interpolants. However, their extension to two or more dimensions can be costly and unstable. An efficient method for computing surface integrals on the sphere is detailed in the literature (Reeger & Fornberg 2016 Stud. Appl. Math.137, 174-188. (doi:10.1111/sapm.12106)). The method uses local radial basis function interpolation to reduce computational complexity when generating quadrature weights for any given node set. This article generalizes this method to arbitrary smooth closed surfaces.
| S-EPMC5095443 | biostudies-other
Project description:For the first time, a comprehensive study of downward flame spread over glass-fiber-reinforced epoxy resin (GFRER) slabs in oxidizer flow has been carried out experimentally and numerically. Microthermocouples were used to measure the temperature profiles on the solid fuel's surface and in the flame, and a video camera was used to measure the rate of flame spread (ROS). The ROS was found to be linearly dependent on the oxygen concentration, to be inversely proportional to the slab thickness and not to depend on the direction of the flame spread over the slab. The absence of the influence of the forced oxidizing flow velocity and the weak influence of the GFRER pyrolysis kinetics on the ROS were observed. For the first time, a numerical model of flame spread over reinforced material with thermal conductivity anisotropy was developed on the basis of a coupled 'gas-solid' heat and mass transfer model, using modifications of the OpenFOAM open-source code. The sensitivity analysis of the model showed that the thermal conductivity in the normal direction to the GFRER surface had a much greater effect on the ROS than the thermal conductivity along the direction of flame propagation. The numerical results show good agreement with the experimental data on the dependences of the ROS on oxygen concentration, slab thickness and the N2/O2 mixture flow velocity, as well as temperature distributions on the fuel surface, the maximum flame temperatures and the flame zone length.
| S-EPMC8912476 | biostudies-literature
Project description:RF arrays with a large number of independent coil elements are advantageous for parallel transmission (pTx) and reception at high fields. One of the main challenges in designing RF arrays is to minimize the electromagnetic (EM) coupling between the coil elements. The induced current elimination (ICE) method, which uses additional resonator elements to cancel coils' mutual EM coupling, has proven to be a simple and efficient solution for decoupling microstrip, L/C loop, monopole and dipole arrays. However, in previous embodiments of conventional ICE decoupling, the decoupling elements acted as "magnetic-walls" with low transmit fields and consequently low MR signal near them. To solve this problem, new resonator geometries including overlapped and perpendicular decoupling loops are proposed. The new geometries were analyzed theoretically and validated in EM simulations, bench tests and MR experiments. The isolation between two closely-placed loops could be improved from about -5dB to <-45dB by using the new geometries.
| S-EPMC5389865 | biostudies-literature
Project description:On April 13, 2021, the CDC announced that the administration of Johnson and Johnson's COVID-19 vaccine would be paused due to a rare blood clotting side effect in ~ 0.0001% of people given the vaccine. Most people who are hesitant to get a COVID-19 vaccine list potential side effects as their main concern (PEW, 2021); thus, it is likely that this announcement increased vaccine hesitancy among the American public. Two days after the CDC's announcement, we administered a survey to a group of 2,046 Americans to assess their changes in attitudes toward COVID-19 vaccines. The aim of this study was to investigate whether viewing icon arrays of side effect risk would prevent increases in COVID-19 vaccine hesitancy due to the announcement. We found that using icon arrays to illustrate the small chance of experiencing the blood clotting side effect significantly prevented increases in aversion toward the Johnson and Johnson vaccine as well as all other COVID-19 vaccines.
| S-EPMC9077983 | biostudies-literature
Project description:ObjectiveSeveral COVID-19 patients have overlapping comorbidities. The independent role of each component contributing to the risk of COVID-19 is unknown, and how some non-cardiometabolic comorbidities affect the risk of COVID-19 remains unclear.MethodsA retrospective follow-up design was adopted. A total of 1,160 laboratory-confirmed patients were enrolled from nine provinces in China. Data on comorbidities were obtained from the patients' medical records. Multivariable logistic regression models were used to estimate the odds ratio ( OR) and 95% confidence interval (95% CI) of the associations between comorbidities (cardiometabolic or non-cardiometabolic diseases), clinical severity, and treatment outcomes of COVID-19.ResultsOverall, 158 (13.6%) patients were diagnosed with severe illness and 32 (2.7%) had unfavorable outcomes. Hypertension (2.87, 1.30-6.32), type 2 diabetes (T2DM) (3.57, 2.32-5.49), cardiovascular disease (CVD) (3.78, 1.81-7.89), fatty liver disease (7.53, 1.96-28.96), hyperlipidemia (2.15, 1.26-3.67), other lung diseases (6.00, 3.01-11.96), and electrolyte imbalance (10.40, 3.00-26.10) were independently linked to increased odds of being severely ill. T2DM (6.07, 2.89-12.75), CVD (8.47, 6.03-11.89), and electrolyte imbalance (19.44, 11.47-32.96) were also strong predictors of unfavorable outcomes. Women with comorbidities were more likely to have severe disease on admission (5.46, 3.25-9.19), while men with comorbidities were more likely to have unfavorable treatment outcomes (6.58, 1.46-29.64) within two weeks.ConclusionBesides hypertension, diabetes, and CVD, fatty liver disease, hyperlipidemia, other lung diseases, and electrolyte imbalance were independent risk factors for COVID-19 severity and poor treatment outcome. Women with comorbidities were more likely to have severe disease, while men with comorbidities were more likely to have unfavorable treatment outcomes.
| S-EPMC7817475 | biostudies-literature
Project description:We numerically study herein the AC electrokinetic motion of Janus mobile microelectrode (ME) arrays in electrolyte solution in a wide field frequency, which holds great potential for biomedical applications. A fully coupled physical model, which incorporates the fluid-structure interaction under the synergy of induced-charge electroosmotic (ICEO) slipping and interfacial Maxwell stress, is developed for this purpose. A freely suspended Janus cylinder free from buoyancy, whose main body is made of polystyrene, while half of the particle surface is coated with a thin conducting film of negligible thickness, will react actively on application of an AC signal. In the low-frequency limit, induced-charge electrophoretic (ICEP) translation occurs due to symmetric breaking in ICEO slipping, which renders the insulating end to move ahead. At higher field frequencies, a brand-new electrokinetic transport phenomenon called "ego-dielectrophoresis (e-DEP)" arises due to the action of the localized uneven field on the inhomogeneous particle dipole moment. In stark contrast with the low-frequency ICEP translation, the high-frequency e-DEP force tends to drive the asymmetric dipole moment to move in the direction of the conducting end. The bidirectional transport feature of Janus microspheres in a wide AC frequency range can be vividly interpreted as an array of ME for continuous loading of secondary bioparticles from the surrounding liquid medium along its direction-controllable path by long-range electroconvection. These results pave the way for achieving flexible and high-throughput on-chip extraction of nanoscale biological contents for subsequent on-site bioassay based upon AC electrokinetics of Janus ME arrays.
| S-EPMC7142959 | biostudies-literature
Project description:Salmonella enterica serotype Typhimurium cause a localized enteric infection in immunocompetent patients while human immunodeficiency virus (HIV)-infected patients develop a life threatening bacteremia. We used a rhesus macaque ileal loop model to study how simian immunodeficiency virus (SIV) infection triggers defects in mucosal barrier function that enhance S. Typhimurium dissemination. SIV infection resulted in significant depletion of CD4+ T cells in the intestinal mucosa. Gene expression profiling revealed a defective TH17 response (with suppression of IL-17 and IL-22 expression) and impaired homeostasis of the intestinal epithelium in SIV-infected animals during NTS infection. These findings correlated with an impaired ability of lamina propria CD4+ T cells from SIV-infected macaques to produce IL-17 upon ex vivo stimulation, while production of IFNï§ was not affected. This cytokine imbalance in SIV-infected animals was associated with reduced expression of genes required for intestinal epithelial maintenance and repair, increased fluid secretion during NTS infection, epithelial damage and translocation of a non-invasive S. Typhimurium mutant. Although no defects in neutrophil recruitment were noted, the ileum of SIV-infected animals contained lower levels of the enzyme myeloperoxidase, which may indicate defects in neutrophil killing capacity. S. Typhimurium was recovered in markedly increased numbers from the mesenteric lymph nodes of SIV-infected macaques, illustrating the increased potential for systemic dissemination during co-infection. Our data suggest that SIV-infection causes a multi-factorial defect in mucosal barrier function that promotes bacterial dissemination. Keywords: Disease state analysis Comparison of ileal gene expression profiles in SIV infected rhesus macaques in response to Salmonella challange.
2010-05-26 | E-GEOD-10567 | biostudies-arrayexpress
Project description:When acquiring information about choice alternatives, decision makers may have varying levels of control over which and how much information they sample before making a choice. How does control over information acquisition affect the quality of sample-based decisions? Here, combining variants of a numerical sampling task with neural recordings, we show that control over when to stop sampling can enhance (i) behavioral choice accuracy, (ii) the build-up of parietal decision signals, and (iii) the encoding of numerical sample information in multivariate electroencephalogram patterns. None of these effects were observed when participants could only control which alternatives to sample, but not when to stop sampling. Furthermore, levels of control had no effect on early sensory signals or on the extent to which sample information leaked from memory. The results indicate that freedom to stop sampling can amplify decisional evidence processing from the outset of information acquisition and lead to more accurate choices.
| S-EPMC9758588 | biostudies-literature
Project description:The National Capital Region (NCR) of India, Delhi, has experienced high post-monsoon pollution along with several peak pollution episodes in recent years. Diwali, the festival of lights, which is among the biggest festivals of India celebrated during the post-monsoon season, is also considered a pollution event associated as it is with the lighting of a large number of firecrackers. 2016 Diwali pollution episode continued for a week creating severe discomfort to residents of Delhi, prompting the judiciary to ban the sale and use of firecrackers in Delhi from 2017 onwards. The current study analyzes different sectoral and temporal emissions contribution to the 2016 post monsoonal pollution episode over Delhi using a fully coupled chemical transport model. The findings of the study indicate that aerosols produced from crop residue open burning at the northwestern states contributed more than 60% of the total simulated surface concentration during the period under study. Model experimental simulations show that despite emissions from within the city, what explains the severity of pollution over Delhi during the period under consideration is an additional pollution load emanating from these intense crop open burning sessions from nearby areas. Further, model simulations show that while Diwali emissions can elevate the pollution load over Delhi, the effects do not last beyond 48 h. It is found that the stagnation of the pollutants several days beyond the 2016 Diwali day was due to favorable meteorological conditions like low surface temperature, lower boundary layer height, and weak northwesterly winds. The study shows that in order to improve air quality in Delhi during the post-monsoon period, mitigation efforts should target the adjacent rural areas, especially when there is massive burning of crop residue in those areas.
| S-EPMC7068672 | biostudies-literature