312 research outputs found

    Coaligned dual-channel STED nanoscopy and molecular diffusion analysis at 20 nm resolution.

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    We report on a fiber laser-based stimulated emission-depletion microscope providing down to ~20 nm resolution in raw data images as well as 15–19 nm diameter probing areas in fluorescence correlation spectroscopy. Stimulated emission depletion pulses of nanosecond duration and 775 nm wavelength are used to silence two fluorophores simultaneously, ensuring offset-free colocalization analysis. The versatility of this superresolution method is exemplified by revealing the octameric arrangement of Xenopus nuclear pore complexes and by quantifying the diffusion of labeled lipid molecules in artificial and living cell membranes

    Computer-controlled characterization of high-voltage, high-frequency SiC devices?

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    A software-based high-voltage curve tracer application for SiC device characterization is presented. This flexible application interface is developed to define testing parameters needed to control the hardware of a custom-made 25 kV-capable SiC characterization test bed. Data acquisition is controlled for optimum resolution, and I-V characterization is computed by means of a user-defined time interval based on the shape of the applied power pulses. Both voltage and current waveforms are displayed for each data point captured to allow the user to observe transient effects. Additionally, the software allows archiving some or all of these transient waveforms. Acquired results are shown to demonstrate functionality and flexibility of the new system. ©2006 IEEE

    Corn Tiller Yield Contributions and Ear Development in Low Plant Densities

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    Research in modern corn (Zea mays L.) hybrids investigating tiller contributions and ear development at low plant densities is scarce, particularly in water-limited environments. To fill this research gap, a second season of replicated experiments was conducted in 2020 at 7 sites across Kansas (Keats, Buhler, Greensburg, Garden City, Goodland, and two sites in Colby) evaluating two common, tiller-prone corn hybrids (P0805AM and P0657AM) at three target plant density levels (10000, 17000, and 24000 plants/a). Five of the listed sites also considered a tillering factor (tiller removal at development stage V10 [tenth-leaf] or tiller maintenance). Seasonal phenology, partitioned grain yield, harvested ear type characterizations, and environmental conditions were recorded and analyzed to quantify tiller contributions in each site. Results showed that intact tillers had either no effect or were able to boost yields. In the best environments, tillers were able to successfully compensate for losses of 60% in plant density. Five of the seven tested sites produced approximately 50% of total harvested ears as desirable tiller lateral ears in the 10000 plants/a target plant density. The highest percentage of undesirable tiller tassel ear development in the 10000 plants/a density was 13%. Future research will seek to find explanations of the ear type relationships on a deeper level and predict tiller yield contributions considering various environments and ear development outcomes

    Echocardiographic predictors of early in-hospital heart failure during first ST-elevation acute myocardial infarction: does myocardial performance index and left atrial volume improve diagnosis over conventional parameters of left ventricular function?

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    <p>Abstract</p> <p>Background</p> <p>Left ventricular ejection fraction (LVEF) has been considered a major determinant of early outcome in acute myocardial infarction (AMI). Myocardial performance index (MPI) has been associated to early evolution in AMI in a heterogeneous population, including non ST-elevation or previous AMI. Left atrial volume has been related with late evolution after AMI. We evaluated the independent role of clinical and echocardiographic variables including LVEF, MPI and left atrial volume in predicting early in-hospital congestive heart failure (CHF) specifically in patients with a first isolated ST-elevation AMI.</p> <p>Methods</p> <p>Echocardiography was performed within 30 hours of chest pain in 95 patients with a first ST-elevation AMI followed during the first week of hospitalization. Several clinical and echocardiographic variables were analyzed. CHF was defined as Killip class ≄ II. Multivariate regression analysis was used to select independent predictor of in-hospital CHF.</p> <p>Results</p> <p>Early in-hospital CHF occurred in 29 (31%) of patients. LVEF ≀ 0.45 was the single independent and highly significant predictor of early CHF among other clinical and echocardiographic variables (odds ratio 17.0; [95% CI 4.1 - 70.8]; p < 0.0001). MPI alone could not predict CHF in first ST-elevation AMI patients. Left atrial volume was not associated with early CHF in such patients.</p> <p>Conclusion</p> <p>For patients with first, isolated ST-elevation AMI, LVEF assessed by echocardiography still constitutes a strong and accurate independent predictor of early in-hospital CHF, superior to isolated MPI and left atrial volume in this particular subset of patients.</p

    Emergency treatment with levetiracetam or phenytoin in status epilepticus in children-the EcLiPSE study: Study protocol for a randomised controlled trial

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    © The Author(s). 2017. Background: Convulsive status epilepticus (CSE) is the most common life-threatening neurological emergency in childhood. These children are also at risk of significant morbidity, with acute and chronic impact on the family and the health and social care systems. The current recommended first-choice, second-line treatment in children aged 6 months and above is intravenous phenytoin (fosphenytoin in the USA), although there is a lack of evidence for its use and it is associated with significant side effects. Emerging evidence suggests that intravenous levetiracetam may be effective as a second-line agent for CSE, and fewer adverse effects have been described. This trial therefore aims to determine whether intravenous phenytoin or levetiracetam is more effective, and safer, in treating childhood CSE. Methods/design: This is a phase IV, multi-centre, parallel group, randomised controlled, open-label trial. Following treatment for CSE with first-line treatment, children with ongoing seizures are randomised to receive either phenytoin (20 mg/kg, maximum 2 g) or levetiracetam (40 mg/kg, maximum 2.5 g) intravenously. The primary outcome measure is the cessation of all visible signs of CSE as determined by the treating clinician. Secondary outcome measures include the need for further anti-seizure medications or rapid sequence induction for ongoing CSE, admission to critical care areas, and serious adverse reactions. Patients are recruited without prior consent, with deferred consent sought at an appropriate time for the family. The primary analysis will be by intention-to-treat. The primary outcome is a time to event outcome and a sample size of 140 participants in each group will have 80% power to detect an increase in CSE cessation rates from 60% to 75%. Our total sample size of 308 randomised and treated participants will allow for 10% loss to follow-up. Discussion: This clinical trial will determine whether phenytoin or levetiracetam is more effective as an intravenous second-line agent for CSE, and provide evidence for management recommendations. In addition, this trial will also provide data on which of these therapies is safer in this setting

    Corn Tiller Yield Contributions are Dependent on Environment: A 17 Site-Year Kansas Study

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    Historic breeding efforts in corn (Zea mays L.) have resulted in uniform, single-stalked phenotypes with limited potential for environmental plasticity. Therefore, plant density is a critical yield component for corn, as corn is unable to successfully compensate for a deficit of plants. Other grass crop species can overcome plant density deficits via vegetative branching (tillering), but this trait is historically undesirable in corn. Improving corn flexibility across plant densities has potential benefits, particularly considering diverse yield environments and seasonal weather uncertainties due to climate change. The present study evaluated tiller presence with two hybrids in a range of plant densities across the state of Kansas to identify yield impacts and potential usefulness of this plasticity trait in corn. Tiller presence was identified as neutral or additive to final yields, but fine-tuning plant density was confirmed as key to maximizing grain yields. Tillers have potential to stabilize yields across plant densities in productive environments. This capability may offer a source of production stability for growers when deficits develop in plant density after planting

    In vivo STED microscopy visualizes morphological changes of large PSD95 assemblies over several hours in the mouse visual cortex

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    Abstract The post-synaptic density (PSD) is an electron dense region consisting of ~1000 proteins, found at the postsynaptic membrane of excitatory synapses, which varies in size depending upon synaptic strength. PSD95 is an abundant scaffolding protein in the PSD and assembles a family of supercomplexes comprised of neurotransmitter receptors, ion channels, as well as signalling and structural proteins. We use superresolution STED (STimulated Emission Depletion) nanoscopy to determine the size and shape of PSD95 in the anaesthetised mouse visual cortex. Adult knock-in mice expressing eGFP fused to the endogenous PSD95 protein were imaged at time points from 1 min to 6 h. Superresolved large assemblies of PSD95 show different sub-structures; most large assemblies were ring-like, some horse-shoe or figure-8 shaped, and shapes were continuous or made up of nanoclusters. The sub-structure appeared stable during the shorter (minute) time points, but after 1 h, more than 50% of the large assemblies showed a change in sub-structure. Overall, these data showed a sub-morphology of large PSD95 assemblies which undergo changes within the 6 hours of observation in the anaesthetised mouse

    How Local Context Affects Populist Radical Right Support: A Cross-National Investigation Into Mediated and Moderated Relationships

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    Populist radical right (PRR) parties are often more successful in some regions of their countries than in others. However, previous research shows that the relationship between context and PRR support is not straightforward. We develop and test an expanded framework linking local conditions to PRR support through two causal mechanisms. First, we argue economic and cultural contextual factors can influence citizens by fostering a sense of perceived local decline, which in turn predicts both populist and nativist attitudes and, hence, PRR support (mediation). Second, we expect that citizens with fewer resources and stronger local embeddedness are more strongly influenced by the context in which they live (moderation). Combining geocoded survey data with contextual data from four countries (DE, FR, GB and NL), we show that the link between local context and PRR support is indeed mediated and moderated, providing a better understanding of the spatial distribution behind recent PRR success

    Mortality among patients with tuberculosis requiring intensive care: a retrospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>To describe the characteristics of patients with tuberculosis (TB) requiring intensive care and to identify the factors that predicts in-hospital mortality in a city of a developing country with intermediate-to-high TB endemicity.</p> <p>Methods</p> <p>We conducted a retrospective, cohort study, between November 2005 and November 2007. The patients with TB requiring intensive care were included. Predictors of mortality were assessed. The primary outcome was the in-hospital mortality.</p> <p>Results</p> <p>During the study period, 67 patients with TB required intensive care. Of them, 62 (92.5%) had acute respiratory failure and required mechanical ventilation. Forty-four (65.7%) patients died. Coinfection with human immunodeficiency virus was present in 46 (68.7%) patients. Early intensive care unit admission and ventilator-associated pneumonia were independently associated with the in-hospital mortality.</p> <p>Conclusions</p> <p>In this study we found a high mortality rate in TB patients requiring intensive care, especially in those with an early ICU admission.</p
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