10,501 research outputs found
High Input Impedance Voltage-Mode Universal Biquadratic Filters With Three Inputs Using Three CCs and Grounding Capacitors
Two current conveyors (CCs) based high input impedance voltage-mode universal biquadratic filters each with three input terminals and one output terminal are presented. The first circuit is composed of three differential voltage current conveyors (DVCCs), two grounded capacitors and four resistors. The second circuit is composed of two DVCCs, one differential difference current conveyor (DDCC), two grounded capacitors and four grounded resistors. The proposed circuits can realize all the standard filter functions, namely, lowpass, bandpass, highpass, notch and allpass filters by the selections of different input voltage terminals. The proposed circuits offer the features of high input impedance, using only grounded capacitors and low active and passive sensitivities. Moreover, the x ports of the DVCCs (or DDCC) in the proposed circuits are connected directly to resistors. This design offers the feature of a direct incorporation of the parasitic resistance at the x terminal of the DVCC (DDCC), Rx, as a part of the main resistance
NbSe3: Effect of Uniaxial Stress on the Threshold Field and Fermiology
We have measured the effect of uniaxial stress on the threshold field ET for
the motion of the upper CDW in NbSe3. ET exhibits a critical behavior, ET ~ (1
- e/ec)^g, wher e is the strain, and ec is about 2.6% and g ~ 1.2. This
ecpression remains valid over more than two decades of ET, up to the highest
fields of about 1.5keV/m. Neither g nor ec is very sensitive to the impurity
concentraction. The CDW transition temperature Tp decreases linearly with e at
a rate dTp/de = -10K/%, and it does not show any anomaly near ec. Shubnikov
de-Haas measurements show that the extremal area of the Fermi surface decreases
with increasing strain. The results suggest that there is an intimate
relationship between pinning of the upper CDW and the Fermiology of NbSe3.Comment: 4 pages, 5 figure
SZ and CMB reconstruction using Generalized Morphological Component Analysis
In the last decade, the study of cosmic microwave background (CMB) data has
become one of the most powerful tools to study and understand the Universe.
More precisely, measuring the CMB power spectrum leads to the estimation of
most cosmological parameters. Nevertheless, accessing such precious physical
information requires extracting several different astrophysical components from
the data. Recovering those astrophysical sources (CMB, Sunyaev-Zel'dovich
clusters, galactic dust) thus amounts to a component separation problem which
has already led to an intense activity in the field of CMB studies. In this
paper, we introduce a new sparsity-based component separation method coined
Generalized Morphological Component Analysis (GMCA). The GMCA approach is
formulated in a Bayesian maximum a posteriori (MAP) framework. Numerical
results show that this new source recovery technique performs well compared to
state-of-the-art component separation methods already applied to CMB data.Comment: 11 pages - Statistical Methodology - Special Issue on Astrostatistics
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Reliability, Responsiveness, and Validity of the Visual Analog Fatigue Scale to Measure Exertion Fatigue in People with Chronic Stroke: A Preliminary Study
Background and Purpose. Post-Stroke Fatigue (PSF) is a prevalent yet commonly neglected issue that impacts daily functions and quality of life in people post-stroke. To date no studies have attempted to validate a clinically-feasible and reliable instrument to quantify PSF. We developed the Visual Analog Fatigue Scale (VAFS) to eliminate difficulties and poor data validity in testing people post-stroke. The purpose of this study was to evaluate the reliability, responsiveness, and validity of the VAFS. Methods. Twenty-one people post-stroke (12 males, age = 59.5 ± 10.3 years; time post-stroke = 4.1 ± 3.5 years) participated. Subjects underwent a standardized fatigue-inducing exercise; fatigue level was assessed at rest, immediately after exercise, and after recovery. The same protocol was repeated after 14 days. Results. ICC values for the VAFS at rest was 0.851 (CI = 95%, 0.673 ∼ 0.936, P < .001), immediately after exercise was 0.846 (CI = 95%, 0.663 ∼ 0.934, P < .001), and 15 minutes after exercise was 0.888 (CI = 95%, 0.749 ∼ 0.953, P < .001). The ES values for at-rest to post-exercise and for post-exercise to post-recovery were 14.512 and 0.685, respectively. Using paired t-test, significant difference was found between VAFS scores at-rest and post-exercise (P < .001), and between post-exercise and post-recovery (P < .001). Conclusion. Our data suggests good reliability, responsiveness, and validity of the VAFS to assess exertion fatigue in people post-stroke
Inhibition of dengue virus replication by novel inhibitors of RNA-dependent RNA polymerase and protease activities
Dengue virus (DENV) is the leading mosquito-transmitted viral infection in the world. With more than 390 million new infections annually, and up to 1 million clinical cases with severe disease manifestations, there continues to be a need to develop new antiviral agents against dengue infection. In addition, there is no approved anti-DENV agents for treating DENV-infected patients. In the present study, we identified new compounds with anti-DENV replication activity by targeting viral replication enzymes – NS5, RNA-dependent RNA polymerase (RdRp) and NS3 protease, using cell-based reporter assay. Subsequently, we performed an enzyme-based assay to clarify the action of these compounds against DENV RdRp or NS3 protease activity. Moreover, these compounds exhibited anti-DENV activity in vivo in the ICR-suckling DENV-infected mouse model. Combination drug treatment exhibited a synergistic inhibition of DENV replication. These results describe novel prototypical small anti-DENV molecules for further development through compound modification and provide potential antivirals for treating DENV infection and DENV-related diseases
α-Actinin and Filamin Cooperatively Enhance the Stiffness of Actin Filament Networks
BACKGROUND: The close subcellular proximity of different actin filament crosslinking proteins suggests that these proteins may cooperate to organize F-actin structures to drive complex cellular functions during cell adhesion, motility and division. Here we hypothesize that alpha-actinin and filamin, two major F-actin crosslinking proteins that are both present in the lamella of adherent cells, display synergistic mechanical functions. METHODOLOGY/PRINCIPAL FINDINGS: Using quantitative rheology, we find that combining alpha-actinin and filamin is much more effective at producing elastic, solid-like actin filament networks than alpha-actinin and filamin separately. Moreover, F-actin networks assembled in the presence of alpha-actinin and filamin strain-harden more readily than networks in the presence of either alpha-actinin or filamin. SIGNIFICANCE: These results suggest that cells combine auxiliary proteins with similar ability to crosslink filaments to generate stiff cytoskeletal structures, which are required for the production of internal propulsive forces for cell migration, and that these proteins do not have redundant mechanical functions
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