143 research outputs found
Dynamics of two-component Bose-Einstein condensates in rotating traps
The dynamics of two-component Bose-Einstein condensates in rotating traps is
investigated. In the Thomas-Fermi limit, equations of motion are derived
showing multiple static solutions for a vortex free condensate. Dynamic
stability analysis of these solutions and comparison with Truncated Wigner
simulations enables us to identify the regimes for which vortex states will
occur. In addition, our analysis predicts centre-of-mass oscillations that are
induced by interspecies interactions and affect each component separately. For
attractive interspecies interactions, these oscillations lead to a stable
symmetry broken state.Comment: v4: more material added. 9 pages, 6 figures v5: figures fixed v6:some
rewording v7:fixed figure
Dynamics of two-component Bose-Einstein condensates in rotating traps
The dynamics of two-component Bose-Einstein condensates in rotating traps is
investigated. In the Thomas-Fermi limit, equations of motion are derived
showing multiple static solutions for a vortex free condensate. Dynamic
stability analysis of these solutions and comparison with Truncated Wigner
simulations enables us to identify the regimes for which vortex states will
occur. In addition, our analysis predicts centre-of-mass oscillations that are
induced by interspecies interactions and affect each component separately. For
attractive interspecies interactions, these oscillations lead to a stable
symmetry broken state.Comment: v4: more material added. 9 pages, 6 figures v5: figures fixed v6:some
rewording v7:fixed figure
Rotation of an atomic Bose-Einstein condensate with and without a quantized vortex
We theoretically examine the rotation of an atomic Bose-Einstein condensate
in an elliptical trap, both in the absence and presence of a quantized vortex.
Two methods of introducing the rotating potential are considered -
adiabatically increasing the rotation frequency at fixed ellipticity, and
adiabatically increasing the trap ellipticity at fixed rotation frequency.
Extensive simulations of the Gross-Pitaevskii equation are employed to map out
the points where the condensate becomes unstable and ultimately forms a vortex
lattice. We highlight the key features of having a quantized vortex in the
initial condensate. In particular, we find that the presence of the vortex
causes the instabilities to shift to lower or higher rotation frequencies,
depending on the direction of the vortex relative to the trap rotation.Comment: 15 pages, 8 figure
MYO1A (myosin IA)
Review on MYO1A, with data on DNA/RNA, on the protein encoded and where the gene is implicated
Carbon incorporation in MOCVD of MoS2 thin films grown from an organosulfide precursor
Altres ajuts: CERCA Programme/Generalitat de CatalunyaWith the rise of two-dimensional (2D) transition-metal dichalcogenide (TMD) semiconductors and their prospective use in commercial (opto)electronic applications, it has become key to develop scalable and reliable TMD synthesis methods with well-monitored and controlled levels of impurities. While metal-organic chemical vapor deposition (MOCVD) has emerged as the method of choice for large-scale TMD fabrication, carbon (C) incorporation arising during MOCVD growth of TMDs has been a persistent concern-especially in instances where organic chalcogen precursors are desired as a less hazardous alternative to more toxic chalcogen hydrides. However, the underlying mechanisms of such unintentional C incorporation and the effects on film growth and properties are still elusive. Here, we report on the role of C-containing side products of organosulfur precursor pyrolysis in MoS2 thin films grown from molybdenum hexacarbonyl Mo(CO)6 and diethyl sulfide (CH3CH2)2S (DES). By combining in situ gas-phase monitoring with ex situ microscopy and spectroscopy analyses, we systematically investigate the effect of temperature and Mo(CO)6/DES/H2 gas mixture ratios on film morphology, chemical composition, and stoichiometry. Aiming at high-quality TMD growth that typically requires elevated growth temperatures and high DES/Mo(CO)6 precursor ratios, we observed that temperatures above DES pyrolysis onset (â 600 °C) and excessive DES flow result in the formation of nanographitic carbon, competing with MoS2 growth. We found that by introducing H2 gas to the process, DES pyrolysis is significantly hindered, which reduces carbon incorporation. The C content in the MoS2 films is shown to quench the MoS2 photoluminescence and influence the trion-To-exciton ratio via charge transfer. This finding is fundamental for understanding process-induced C impurity doping in MOCVD-grown 2D semiconductors and might have important implications for the functionality and performance of (opto)electronic devices
Starvation sensing by mycobacterial RelA/SpoT homologue through constitutive surveillance of translation
The stringent response, which leads to persistence of nutrient-starved mycobacteria, is induced by activation of the RelA/SpoT homolog (Rsh) upon entry of a deacylated-tRNA in a translating ribosome. However, the mechanism by which Rsh identifies such ribosomes in vivo remains unclear. Here, we show that conditions inducing ribosome hibernation result in loss of intracellular Rsh in a Clp protease-dependent manner. This loss is also observed in nonstarved cells using mutations in Rsh that block its interaction with the ribosome, indicating that Rsh association with the ribosome is important for Rsh stability. The cryo-EM structure of the Rsh-bound 70S ribosome in a translation initiation complex reveals unknown interactions between the ACT domain of Rsh and components of the ribosomal L7/L12 stalk base, suggesting that the aminoacylation status of A-site tRNA is surveilled during the first cycle of elongation. Altogether, we propose a surveillance model of Rsh activation that originates from its constitutive interaction with the ribosomes entering the translation cycle
Integrated sensor-augmented pump therapy systems [the MiniMed® Paradigm™ Veo system and the Vibe™ and G4® PLATINUM CGM (continuous glucose monitoring) system] for managing blood glucose levels in type 1 diabetes: A systematic review and economic evaluation
Background: In recent years, meters for continuous monitoring of interstitial fluid glucose have been introduced to help people with type 1 diabetes mellitus (T1DM) to achieve better control of their disease. Objective: The objective of this project was to summarise the evidence on the clinical effectiveness and cost-effectiveness of the MiniMed® Paradigm™ Veo system (Medtronic Inc., Northridge, CA, USA) and the Vibe™ (Animas® Corporation, West Chester, PA, USA) and G4® PLATINUM CGM (continuous glucose monitoring) system (Dexcom Inc., San Diego, CA, USA) in comparison with multiple daily insulin injections (MDIs) or continuous subcutaneous insulin infusion (CSII), both with either self-monitoring of blood glucose (SMBG) or CGM, for the management of T1DM in adults and children. Data sources: A systematic review was conducted in accordance with the principles of the Centre for Reviews and Dissemination guidance and the National Institute for He
SeHCAT [tauroselcholic (selenium-75) acid] for the investigation of bile acid malabsorption and measurement of bile acid pool loss
Background
The principal diagnosis/indication for this assessment is chronic diarrhoea due to bile acid malabsorption (BAM). Diarrhoea can be defined as the abnormal passage of loose or liquid stools more than three times daily and/or a daily stool weight > 200 g per day and is considered to be chronic if it persists for more than 4 weeks. The cause of chronic diarrhoea in adults is often difficult to ascertain and patients may undergo several investigations without a definitive cause being identified. BAM is one of several causes of chronic diarrhoea and results from failure to absorb bile acids (which are required for the absorption of dietary fats and sterols in the intestine) in the distal ileum.
Objective
For people with chronic diarrhoea with unknown cause and in people with Crohn's disease and chronic diarrhoea with unknown cause (i.e. before resection): (1) What are the effects of selenium-75-homocholic acid taurine (SeHCAT) compared with no SeHCAT in terms of chronic diarrhoea, other health outcomes and costs? (2) What are the effects of bile acid sequestrants (BASs) compared with no BASs in people with a positive or negative SeHCAT test? (3) Does a positive or negative SeHCAT test predict improvement in terms of chronic diarrhoea, other health outcomes and costs?
Data sources
A systematic review was conducted to summarise the evidence on the clinical effectiveness of SeHCAT for the assessment of BAM and the measurement of bile acid pool loss. Search strategies were based on target condition and intervention, as recommended in the Centre for Reviews and Dissemination (CRD) guidance for undertaking reviews in health care and the Cochrane Handbook for Diagnostic Test Accuracy Reviews. The following databases were searched up to April 2012: MEDLINE; MEDLINE In-Process & Other Non-Indexed Citations; EMBASE; the Cochrane Databases; Database of Abstracts of Reviews of Effects; Health Technology Assessment (HTA) Database; and Science Citation Index. Research registers and conference proceedings were also searched.
Review methods
Systematic review methods followed the principle
Full-bandwidth electrophysiology of seizures and epileptiform activity enabled by flexible graphene microtransistor depth neural probes
Mapping the entire frequency bandwidth of brain electrophysiological signals is of paramount importance for understanding physiological and pathological states. The ability to record simultaneously DC-shifts, infraslow oscillations (<0.1 Hz), typical local field potentials (0.1-80 Hz) and higher frequencies (80-600 Hz) using the same recording site would particularly benefit preclinical epilepsy research and could provide clinical biomarkers for improved seizure onset zone delineation. However, commonly used metal microelectrode technology suffers from instabilities that hamper the high fidelity of DC-coupled recordings, which are needed to access signals of very low frequency. In this study we used flexible graphene depth neural probes (gDNPs), consisting of a linear array of graphene microtransistors, to concurrently record DC-shifts and high-frequency neuronal activity in awake rodents. We show here that gDNPs can reliably record and map with high spatial resolution seizures, pre-ictal DC-shifts and seizure-associated spreading depolarizations together with higher frequencies through the cortical laminae to the hippocampus in a mouse model of chemically induced seizures. Moreover, we demonstrate the functionality of chronically implanted devices over 10 weeks by recording with high fidelity spontaneous spike-wave discharges and associated infraslow oscillations in a rat model of absence epilepsy. Altogether, our work highlights the suitability of this technology for in vivo electrophysiology research, and in particular epilepsy research, by allowing stable and chronic DC-coupled recordings
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