3,938 research outputs found
Recurrent Delocalization and Quasiequilibration of Photons in Coupled Systems in Circuit Quantum Electrodynamics
We explore the photon population dynamics in two coupled circuit QED systems. For a sufficiently weak intercavity photon hopping, as the photon-cavity coupling increases, the dynamics undergoes double transitions first from a delocalized to a localized phase and then from the localized to another delocalized phase. The latter delocalized phase is distinguished from the former one; instead of oscillating between the two cavities, the photons rapidly quasiequilibrate over the two cavities. These intriguing features are attributed to an interplay between two qualitatively distinctive nonlinear behaviors of the circuit QED systems in the utrastrong coupling regime, whose distinction has been widely overlooked
Twinning-mediated formability in Mg alloys
Mg alloys are promising candidates for automotive applications due to their low density and high specific strength. However, their widespread applications have not been realized mainly because of poor formability at room temperature, arising from limited number of active deformation systems and strong basal texture. It has been recently shown that Mg-Zn-Ca alloys have excellent stretch formability, which has been ascribed to their weak basal texture. However, the distribution of basal poles is orthotropic, which might result in anisotropy during deformation and have adverse effect on formability. Here, we show that tension twinning is mainly responsible for enhanced formability of Mg-Zn-Ca alloys. We found that tension twinning is quite active during both uniaxial deformation and biaxial deformation of Mg-Zn-Ca alloy even under the stress conditions unfavourable for the formation of tensile twins. Our results provide new insights into the development of Mg alloys having high formability.112514Ysciescopu
Mesenchymal stem cell-based therapy for ischemic stroke
Ischemic stroke represents a major, worldwide health burden with increasing incidence. Patients affected by ischemic strokes currently have few clinically approved treatment options available. Most currently approved treatments for ischemic stroke have narrow therapeutic windows, severely limiting the number of patients able to be treated. Mesenchymal stem cells represent a promising novel treatment for ischemic stroke. Numerous studies have demonstrated that mesenchymal stem cells functionally improve outcomes in rodent models of ischemic stroke. Recent studies have also shown that exosomes secreted by mesenchymal stem cells mediate much of this effect. In the present review, we summarize the current literature on the use of mesenchymal stem cells to treat ischemic stroke. Further studies investigating the mechanisms underlying mesenchymal stem cells tissue healing effects are warranted and would be of benefit to the field
The effect of cigarette price increase on the cigarette consumption in Taiwan: evidence from the National Health Interview Surveys on cigarette consumption
BACKGROUND: This study uses cigarette price elasticity to evaluate the effect of a new excise tax increase on cigarette consumption and to investigate responses from various types of smokers. METHODS: Our sample consisted of current smokers between 17 and 69 years old interviewed during an annual face-to-face survey conducted by Taiwan National Health Research Institutes between 2000 to 2003. We used Ordinary Least Squares (OLS) procedure to estimate double logarithmic function of cigarette demand and cigarette price elasticity. RESULTS: In 2002, after Taiwan had enacted the new tax scheme, cigarette price elasticity in Taiwan was found to be -0.5274. The new tax scheme brought about an average annual 13.27 packs/person (10.5%) reduction in cigarette consumption. Using the cigarette price elasticity estimate from -0.309 in 2003, we calculated that if the Health and Welfare Tax were increased by another NT$ 3 per pack and cigarette producers shifted this increase to the consumers, cigarette consumption would be reduced by 2.47 packs/person (2.2%). The value of the estimated cigarette price elasticity is smaller than one, meaning that the tax will not only reduce cigarette consumption but it will also generate additional tax revenues. Male smokers who had no income or who smoked light cigarettes were found to be more responsive to changes in cigarette price. CONCLUSIONS: An additional tax added to the cost of cigarettes would bring about a reduction in cigarette consumption and increased tax revenues. It would also help reduce incidents smoking-related illnesses. The additional tax revenues generated by the tax increase could be used to offset the current financial deficiency of Taiwan's National Health Insurance program and provide better public services
Generic Mechanism of Emergence of Amyloid Protofilaments from Disordered Oligomeric aggregates
The presence of oligomeric aggregates, which is often observed during the
process of amyloid formation, has recently attracted much attention since it
has been associated with neurodegenerative conditions such as Alzheimer's and
Parkinson's diseases. We provide a description of a sequence-indepedent
mechanism by which polypeptide chains aggregate by forming metastable
oligomeric intermediate states prior to converting into fibrillar structures.
Our results illustrate how the formation of ordered arrays of hydrogen bonds
drives the formation of beta-sheets within the disordered oligomeric aggregates
that form early under the effect of hydrophobic forces. Initially individual
beta-sheets form with random orientations, which subsequently tend to align
into protofilaments as their lengths increases. Our results suggest that
amyloid aggregation represents an example of the Ostwald step rule of first
order phase transitions by showing that ordered cross-beta structures emerge
preferentially from disordered compact dynamical intermediate assemblies.Comment: 14 pages, 4 figure
Measuring V_ub and probing SUSY with double ratios of purely leptonic decays of B and D mesons
The experimental prospects for precise measurements of the leptonic decays
B_u -> tau nu / mu nu, B_s -> mu+ mu-, D -> mu nu and D_s -> mu nu / tau nu are
very promising. Double ratios involving four of these decays can be defined in
which the dependence on the values of the decay constants is essentially
eliminated, thus enabling complementary measurements of the CKM matrix element
V_ub with a small theoretical error. We quantify the experimental error in a
possible future measurement of |V_ub| using this approach, and show that it is
competitive with the anticipated precision from the conventional approaches.
Moreover, it is shown that such double ratios can be more effective than the
individual leptonic decays as a probe of the parameter space of supersymmetric
models. We emphasize that the double ratios have the advantage of using |V_ub|
as an input parameter (for which there is experimental information), while the
individual decays have an uncertainty from the decay constants (e.g. f_B_s),
and hence a reliance on theoretical techniques such as lattice QCD.Comment: 21 pages, 4 figure
Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution
Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of similar to 50% at 20 C compared to that at 0.2 C-rate) and cycle retention (73% at 3.0 C-rate) with a retaining capacity of 546 mAh g(-1) even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system
WNT signaling regulates self-renewal and differentiation of prostate cancer cells with stem cell characteristics
Prostate cancer cells with stem cell characteristics were identified in human prostate cancer cell lines by their ability to form from single cells self-renewing prostaspheres in non-adherent cultures. Prostaspheres exhibited heterogeneous expression of proliferation, differentiation and stem cell-associated makers CD44, ABCG2 and CD133. Treatment with WNT inhibitors reduced both prostasphere size and self-renewal. In contrast, addition of Wnt3a caused increased prostasphere size and self-renewal, which was associated with a significant increase in nuclear Β-catenin, keratin 18, CD133 and CD44 expression. As a high proportion of LNCaP and C4-2B cancer cells express androgen receptor we determined the effect of the androgen receptor antagonist bicalutamide. Androgen receptor inhibition reduced prostasphere size and expression of PSA, but did not inhibit prostasphere formation. These effects are consistent with the androgen-independent self-renewal of cells with stem cell characteristics and the androgen-dependent proliferation of transit amplifying cells. As the canonical WNT signaling effector Β-catenin can also associate with the androgen receptor, we propose a model for tumour propagation involving a balance between WNT and androgen receptor activity. That would affect the self-renewal of a cancer cell with stem cell characteristics and drive transit amplifying cell proliferation and differentiation. In conclusion, we provide evidence that WNT activity regulates the self-renewal of prostate cancer cells with stem cell characteristics independently of androgen receptor activity. Inhibition of WNT signaling therefore has the potential to reduce the self-renewal of prostate cancer cells with stem cell characteristics and improve the therapeutic outcome.Peer reviewe
A Condensation-Ordering Mechanism in Nanoparticle-Catalyzed Peptide Aggregation
Nanoparticles introduced in living cells are capable of strongly promoting
the aggregation of peptides and proteins. We use here molecular dynamics
simulations to characterise in detail the process by which nanoparticle
surfaces catalyse the self- assembly of peptides into fibrillar structures. The
simulation of a system of hundreds of peptides over the millisecond timescale
enables us to show that the mechanism of aggregation involves a first phase in
which small structurally disordered oligomers assemble onto the nanoparticle
and a second phase in which they evolve into highly ordered beta-sheets as
their size increases
Dissociation Between the Growing Opioid Demands and Drug Policy Directions Among the U.S. Older Adults with Degenerative Joint Diseases
We aim to examine temporal trends of orthopedic operations and opioid-related hospital stays among seniors in the nation and states of Oregon and Washington where marijuana legalization was accepted earlier than any others. As aging society advances in the United States (U.S.), orthopedic operations and opioid-related hospital stays among seniors increase in the nation. A serial cross-sectional cohort study using the healthcare cost and utilization project fast stats from 2006 through 2015 measured annual rate per 100,000 populations of orthopedic operations by age groups (45–64 vs 65 and older) as well as annual rate per 100,000 populations of opioid-related hospital stays among 65 and older in the nation, Oregon and Washington states from 2008 through 2017. Orthopedic operations (knee arthroplasty, total or partial hip replacement, spinal fusion or laminectomy) and opioid-related hospital stays were measured. The compound annual growth rate (CAGR) was used to quantify temporal trends of orthopedic operations by age groups as well as opioid-related hospital stays and was tested by Rao–Scott correction of χ2 for categorical variables. The CAGR (4.06%) of orthopedic operations among age 65 and older increased (P...) (See full abstract in article
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