680 research outputs found
Border Terriers under primary veterinary care in England: demography and disorders
The Border Terrier is a working terrier type that is generally considered to be a relatively healthy and hardy breed. This study aimed to characterise the demography and common disorders of Border Terriers receiving veterinary care in England using de-identified electronic patient record data within the VetCompass™ Programme
Comparison between Bipolar Hemiarthroplasty and Total Hip Arthroplasty for Unstable Intertrochanteric Fractures in Elderly Osteoporotic Patients
The present study was conducted to compare bipolar hemiarthroplasty (BA) with total hip arthroplasty (THA) in treatment of unstable intertrochanteric fractures in elderly osteoporotic patients. The THA group included 14 males and 26 females with a mean age of 73.4 years, and the BA group included 27 males and 45 females with a mean age of 76.5 years. Significant difference existed between the two groups in operation time, blood loss, transfusion volume and cost of hospitalization, while no remarkable difference was identified in hospitalization period, general complications, joint function, pain, rate of revision and mortality. No dislocation was observed in BA group while 3 occurred in THA group. The results indicated that for unstable intertrochanteric fractures in elderly osteoporotic patients, BA seems to be a better or more reasonable choice compared with THA for the reason of less blood loss, shorter operation time, lower cost and no dislocation
HIV Traffics through a Specialized, Surface-Accessible Intracellular Compartment during trans-Infection of T Cells by Mature Dendritic Cells
In vitro, dendritic cells (DCs) bind and transfer intact, infectious HIV to CD4 T cells without first becoming infected, a process known as trans-infection. trans-infection is accomplished by recruitment of HIV and its receptors to the site of DC–T cell contact and transfer of virions at a structure known as the infectious synapse. In this study, we used fluorescent microscopy to track individual HIV particles trafficking in DCs during virus uptake and trans-infection. Mature DCs rapidly concentrated HIV into an apparently intracellular compartment that lacked markers characteristic of early endosomes, lysosomes, or antigen-processing vesicles. Live cell microscopy demonstrated that the HIV-containing compartment was rapidly polarized toward the infectious synapse after contact with a T cell; however, the bulk of the concentrated virus remained in the DCs after T cell engagement. Individual virions were observed emerging from the compartment and fusing with the T cell membrane at the infectious synapse. The compartmentalized HIV, although engulfed by the cytoplasm, was fully accessible to HIV envelope-specific inhibitors and other membrane-impermeable probes that were delivered to the cell surface. These results demonstrate that HIV resides in an invaginated domain within DCs that is both contiguous with the plasma membrane and distinct from endocytic vesicles. We conclude that HIV virions are routed through this specialized compartment, which allows individual particles to be delivered to T cells during trans-infection
Franck-Condon blockade in suspended carbon nanotube quantum dots
Understanding the influence of vibrational motion of the atoms on electronic
transitions in molecules constitutes a cornerstone of quantum physics, as
epitomized by the Franck-Condon principle of spectroscopy. Recent advances in
building molecular-electronics devices and nanoelectromechanical systems open a
new arena for studying the interaction between mechanical and electronic
degrees of freedom in transport at the single-molecule level. The tunneling of
electrons through molecules or suspended quantum dots has been shown to excite
vibrational modes, or vibrons. Beyond this effect, theory predicts that strong
electron-vibron coupling dramatically suppresses the current flow at low
biases, a collective behaviour known as Franck-Condon blockade. Here we show
measurements on quantum dots formed in suspended single-wall carbon nanotubes
revealing a remarkably large electron-vibron coupling and, due to the high
quality and unprecedented tunability of our samples, admit a quantitative
analysis of vibron-mediated electronic transport in the regime of strong
electron-vibron coupling. This allows us to unambiguously demonstrate the
Franck-Condon blockade in a suspended nanostructure. The large observed
electron-vibron coupling could ultimately be a key ingredient for the detection
of quantized mechanical motion. It also emphasizes the unique potential for
nanoelectromechanical device applications based on suspended graphene sheets
and carbon nanotubes.Comment: 7 pages, 3 figure
Mapping Differentiation under Mixed Culture Conditions Reveals a Tunable Continuum of T Cell Fates
Cell differentiation is typically directed by external signals that drive opposing regulatory pathways. Studying differentiation under polarizing conditions, with only one input signal provided, is limited in its ability to resolve the logic of interactions between opposing pathways. Dissection of this logic can be facilitated by mapping the system's response to mixtures of input signals, which are expected to occur in vivo, where cells are simultaneously exposed to various signals with potentially opposing effects. Here, we systematically map the response of naïve T cells to mixtures of signals driving differentiation into the Th1 and Th2 lineages. We characterize cell state at the single cell level by measuring levels of the two lineage-specific transcription factors (T-bet and GATA3) and two lineage characteristic cytokines (IFN-γ and IL-4) that are driven by these transcription regulators. We find a continuum of mixed phenotypes in which individual cells co-express the two lineage-specific master regulators at levels that gradually depend on levels of the two input signals. Using mathematical modeling we show that such tunable mixed phenotype arises if autoregulatory positive feedback loops in the gene network regulating this process are gradual and dominant over cross-pathway inhibition. We also find that expression of the lineage-specific cytokines follows two independent stochastic processes that are biased by expression levels of the master regulators. Thus, cytokine expression is highly heterogeneous under mixed conditions, with subpopulations of cells expressing only IFN-γ, only IL-4, both cytokines, or neither. The fraction of cells in each of these subpopulations changes gradually with input conditions, reproducing the continuous internal state at the cell population level. These results suggest a differentiation scheme in which cells reflect uncertainty through a continuously tuneable mixed phenotype combined with a biased stochastic decision rather than a binary phenotype with a deterministic decision
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
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