12,080 research outputs found
Determinations of upper critical field in continuous Ginzburg-Landau model
Novel procedures to determine the upper critical field have been
proposed within a continuous Ginzburg-Landau model. Unlike conventional
methods, where is obtained through the determination of the smallest
eigenvalue of an appropriate eigen equation, the square of the magnetic field
is treated as eigenvalue problems so that the upper critical field can be
directly deduced. The calculated from the two procedures are
consistent with each other and in reasonably good agreement with existing
theories and experiments. The profile of the order parameter associated with
is found to be Gaussian-like, further validating the methodology
proposed. The convergences of the two procedures are also studied.Comment: Revtex4, 8 pages, 4 figures, references modified, figures and table
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Corticostriatal Transmission Is Selectively Enhanced in Striatonigral Neurons with Postnatal Loss of Tsc1.
mTORC1 is a central signaling hub that integrates intra- and extracellular signals to regulate a variety of cellular metabolic processes. Mutations in regulators of mTORC1 lead to neurodevelopmental disorders associated with autism, which is characterized by repetitive, inflexible behaviors. These behaviors may result from alterations in striatal circuits that control motor learning and habit formation. However, the consequences of mTORC1 dysregulation on striatal neuron function are largely unknown. To investigate this, we deleted the mTORC1 negative regulator Tsc1 from identified striatonigral and striatopallidal neurons and examined how cell-autonomous upregulation of mTORC1 activity affects their morphology and physiology. We find that loss of Tsc1 increases the excitability of striatonigral, but not striatopallidal, neurons and selectively enhances corticostriatal synaptic transmission. These findings highlight the critical role of mTORC1 in regulating striatal activity in a cell type- and input-specific manner, with implications for striatonigral pathway dysfunction in neuropsychiatric disease
Kinetic Equation for a Plasma and Its Application to High-frequency Conductivity
Kinetic equation for inhomogenious nonisotropic plasma and application to high frequency conductivit
A fluorescence in situ staining method for investigating spores and vegetative cells of Clostridia by confocal laser scanning microscopy and structured illuminated microscopy
Non-pathogenic spore-forming Clostridia are of increasing interest due to their application in biogas production
and their capability to spoil different food products. The life cycle for Clostridium includes a spore stage that can
assist in survival under environmentally stressful conditions, such as extremes of temperature or pH. Due to their
size, spores can be investigated by a range of microscopic techniques, many of which involve sample pretreatment.
We have developed a quick, simple and non-destructive fluorescent staining procedure that allows a
clear differentiation between spores and vegetative cells and effectively stains spores, allowing recovery and
tracking in subsequent experiments. Hoechst 34580, Propidium iodide and wheat germ agglutinin WGA 488
were used in combination to stain four strains of Clostridia at different life cycle stages. Staining was conducted
without drying the sample, preventing changes induced by dehydration and cells observed by confocal laser
scanner microscopy or using a super-resolution microscope equipped with a 3D-structured illumination module.
Dual staining with Hoechst/Propidium iodide differentiated spores from vegetative cells, provided information
on the viability of cells and was successfully applied to follow spore production induced by heating. Superresolution
microscopy of spores probed by Hoechst 34580 also allowed chromatin to be visualised. Direct
staining of a cheese specimen using Nile Red and Fast Green allowed in situ observation of spores within the
cheese and their position within the cheese matrix. The proposed staining method has broad applicability and
can potentially be applied to follow Clostridium spore behaviour in a range of different environments
Integrin α2β1 Expression Regulates Matrix Metalloproteinase-1-Dependent Bronchial Epithelial Repair in Pulmonary Tuberculosis.
Pulmonary tuberculosis (TB) is caused by inhalation of Mycobacterium tuberculosis, which damages the bronchial epithelial barrier to establish local infection. Matrix metalloproteinase-1 plays a crucial role in the immunopathology of TB, causing breakdown of type I collagen and cavitation, but this collagenase is also potentially involved in bronchial epithelial repair. We hypothesized that the extracellular matrix (ECM) modulates M. tuberculosis-driven matrix metalloproteinase-1 expression by human bronchial epithelial cells (HBECs), regulating respiratory epithelial cell migration and repair. Medium from monocytes stimulated with M. tuberculosis induced collagenase activity in bronchial epithelial cells, which was reduced by ~87% when cells were cultured on a type I collagen matrix. Matrix metalloproteinase-1 had a focal localization, which is consistent with cell migration, and overall secretion decreased by 32% on type I collagen. There were no associated changes in the specific tissue inhibitors of metalloproteinases. Decreased matrix metalloproteinase-1 secretion was due to ligand-binding to the α2β1 integrin and was dependent on the actin cytoskeleton. In lung biopsies, samples from patients with pulmonary TB, integrin α2β1 is highly expressed on the bronchial epithelium. Areas of lung with disrupted collagen matrix showed an increase in matrix metalloproteinases-1 expression compared with areas where collagen was comparable to control lung. Type I collagen matrix increased respiratory epithelial cell migration in a wound-healing assay, and this too was matrix metalloproteinase-dependent, since it was blocked by the matrix metalloproteinase inhibitor GM6001. In summary, we report a novel mechanism by which α2β1-mediated signals from the ECM modulate matrix metalloproteinase-1 secretion by HBECs, regulating their migration and epithelial repair in TB
Predictive Modelling Using Unstructured Data From Online Forums: A Case Study on E-cigarette Users
In the age of the digital economy, social media, forums and other online platforms have played active parts in our daily activities. The amount of data digitized and recorded in these platforms have surged exponentially. Many believed that this underexplored unstructured data sources have huge potential in offering insights to policy makers and companies. This paper aims to propose a hybrid approach using inductive and deductive reasoning to identify motivational factors to use e-cigarettes for predictive modelling. A total of 790 comments and discussions relevant to e-cigarette use and motivations to use e-cigarette were scraped and stored from online forums like Reddit, Vapingunderground and e-cigarette-forum. A series of text analytics were conducted on the text corpus and the cluster analysis enabled us to build a predictive model. Using Bayesian Structural Equation Modelling, we concluded that the constructs derived by clustering, i.e. Cost and Convenience and Enjoyment, have significant associations with smokers trying to quit smoking. While health-related issues were inherent to the notion of quitting smoking, enjoyment, cost and convenience were motivational factors which will generate favourable response towards quitting smoking. The findings showed encouraging results from a methodological standpoint and offered insights to policy makers and companies on health-related issues pertaining to the use of e-cigarettes
Assembly Guidance in Augmented Reality Environments Using a Virtual Interactive Tool
The application of augmented reality (AR) technology for assembly guidance is a novel approach in the traditional manufacturing domain. In this paper, we propose an AR approach for assembly guidance using a virtual interactive tool that is intuitive and easy to use. The virtual interactive tool, termed the Virtual Interaction Panel (VirIP), involves two tasks: the design of the VirIPs and the real-time tracking of an interaction pen using a Restricted Coulomb Energy (RCE) neural network. The VirIP includes virtual buttons, which have meaningful assembly information that can be activated by an interaction pen during the assembly process. A visual assembly tree structure (VATS) is used for information management and assembly instructions retrieval in this AR environment. VATS is a hierarchical tree structure that can be easily maintained via a visual interface. This paper describes a typical scenario for assembly guidance using VirIP and VATS. The main characteristic of the proposed AR system is the intuitive way in which an assembly operator can easily step through a pre-defined assembly plan/sequence without the need of any sensor schemes or markers attached on the assembly components.Singapore-MIT Alliance (SMA
Empires and Percolation: Stochastic Merging of Adjacent Regions
We introduce a stochastic model in which adjacent planar regions merge
stochastically at some rate , and observe analogies with the
well-studied topics of mean-field coagulation and of bond percolation. Do
infinite regions appear in finite time? We give a simple condition on
for this {\em hegemony} property to hold, and another simple condition for it
to not hold, but there is a large gap between these conditions, which includes
the case . For this case, a non-rigorous analytic
argument and simulations suggest hegemony.Comment: 13 page
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