4,144 research outputs found
Nanoscale state-of-charge heterogeneities within polycrystalline nickel-rich layered oxide cathode materials
Nickel-rich cathodes (LiNixMnyCo1-x-yO2, x > 0.6) permit higher energy in lithium-ion rechargeable batteries but suffer from accelerated degradation at potentials above 4.1 V versus Li/Li+. Here, we present a proof-of-concept in situ pouch cell and methodology for correlative 2D synchrotron transmission X-ray microscopy with 3D lab-based micro-CT. XANES analysis of the TXM data enables tracking of Ni edge energy within and between the polycrystalline NMC811 particles embedded in the operating electrode through its initial delithiation. By using edge energy as a proxy, state-of-charge heterogeneities can be tracked at the nanoscale, revealing the role of cracked particles as potential nucleation points for failure and highlighting the challenges in achieving uniform (de-)lithiation. We propose, in future work, to leverage the pouch cell design presented here for longitudinal TXM-XANES studies of nickel-rich cathodes across multiple cycles and operating variables and investigate the effect of dopants and microstructural optimization in mitigating degradation
Health-related quality of life as measured with EQ-5D among populations with and without specific chronic conditions: A population-based survey in Shaanxi province, China
© 2013 Tan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Introduction: The aim of this study was to examine health-related quality of life (HRQoL) as measured by EQ-5D and to investigate the influence of chronic conditions and other risk factors on HRQoL based on a distributed sample located in Shaanxi Province, China. Methods: A multi-stage stratified cluster sampling method was performed to select subjects. EQ-5D was employed to measure the HRQoL. The likelihood that individuals with selected chronic diseases would report any problem in the EQ-5D dimensions was calculated and tested relative to that of each of the two reference groups. Multivariable linear regression models were used to investigate factors associated with EQ VAS. Results: The most frequently reported problems involved pain/discomfort (8.8%) and anxiety/depression (7.6%). Nearly half of the respondents who reported problems in any of the five dimensions were chronic patients. Higher EQ VAS scores were associated with the male gender, higher level of education, employment, younger age, an urban area of residence, access to free medical service and higher levels of physical activity. Except for anemia, all the selected chronic diseases were indicative of a negative EQ VAS score. The three leading risk factors were cerebrovascular disease, cancer and mental disease. Increases in age, number of chronic conditions and frequency of physical activity were found to have a gradient effect. Conclusion: The results of the present work add to the volume of knowledge regarding population health status in this area, apart from the known health status using mortality and morbidity data. Medical, policy, social and individual attention should be given to the management of chronic diseases and improvement of HRQoL. Longitudinal studies must be performed to monitor changes in HRQoL and to permit evaluation of the outcomes of chronic disease intervention programs. © 2013 Tan et al.National Nature Science Foundation (No. 8107239
The all-particle spectrum of primary cosmic rays in the wide energy range from 10^14 eV to 10^17 eV observed with the Tibet-III air-shower array
We present an updated all-particle energy spectrum of primary cosmic rays in
a wide range from 10^14 eV to 10^17 eV using 5.5 times 10^7 events collected in
the period from 2000 November through 2004 October by the Tibet-III air-shower
array located at 4300 m above sea level (atmospheric depth of 606 g/cm^2). The
size spectrum exhibits a sharp knee at a corresponding primary energy around 4
PeV. This work uses increased statistics and new simulation calculations for
the analysis. We performed extensive Monte Carlo calculations and discuss the
model dependences involved in the final result assuming interaction models of
QGSJET01c and SIBYLL2.1 and primary composition models of heavy dominant (HD)
and proton dominant (PD) ones. Pure proton and pure iron primary models are
also examined as extreme cases. The detector simulation was also made to
improve the accuracy of determining the size of the air showers and the energy
of the primary particle. We confirmed that the all-particle energy spectra
obtained under various plausible model parameters are not significantly
different from each other as expected from the characteristics of the
experiment at the high altitude, where the air showers of the primary energy
around the knee reaches near maximum development and their features are
dominated by electromagnetic components leading to the weak dependence on the
interaction model or the primary mass. This is the highest-statistical and the
best systematics-controlled measurement covering the widest energy range around
the knee energy region.Comment: 19 pages, 20 figures, accepted by Ap
Long-term Prognostic Value of Cardiac MRI Left Atrial Strain in ST-Segment Elevation Myocardial Infarction
Background:
Left atrial (LA) dysfunction is associated with morbidity and mortality. To the knowledge of the authors, the relationship of LA strain to long-term prognosis in participants with ST-segment elevation myocardial infarction (STEMI) is unknown. /
Purpose:
To evaluate LA strain as a long-term outcome predictor in STEMI in a prospective, multicenter cardiac MRI cohort. /
Materials and Methods:
Participants with STEMI who underwent primary percutaneous coronary intervention and cardiac MRI from 10 sites (EARLY-MYO-CMR registry, clinical trial number NCT03768453) were included. The parent study took place between August 2013 and December 2018. LA longitudinal strain and strain rate parameters were derived from cine cardiac MRI by using an in-house semiautomated method. Major adverse cardiac events (MACEs) were defined as cardiovascular death, myocardial reinfarction, hospitalization for heart failure, and stroke. The association between LA performance and MACE was evaluated by using time-dependent receiver operating characteristic analysis, Kaplan-Meier analysis, and multivariable Cox regression analysis. /
Results:
A total of 321 participants (median age, 59 years; age range, 27–75 years; 90% men) were included in this study. During median follow-up of 3.7 years, MACE occurred in 76 participants (23.7%). Participants with impaired reservoir (≤22%) and conduit strain (≤10%) had a higher risk of MACE than those with reservoir strain greater than 22% and conduit strain greater than 10% (P < .001). Reservoir strain (hazard ratio, 0.84; 95% confidence interval: 0.77, 0.91; P < .001) and conduit strain (hazard ratio, 0.81; 95% confidence interval: 0.73, 0.89; P < .001) were independent predictors for MACE after adjustment for known risk factors. Finally, LA reservoir and conduit strains provided incremental prognostic value over traditional outcome predictors (Uno C statistic comparing models, 0.75 vs 0.68; P = .04). /
Conclusion:
Assessment of left atrial strain, as a measure of left atrial function, provided incremental prognostic information to established predictors in ST-segment elevation myocardial infarction
Entanglement-enhanced testing of multiple quantum hypotheses
Quantum hypothesis testing has been greatly advanced for the binary discrimination of two states, or two channels. In this setting, we already know that quantum entanglement can be used to enhance the discrimination of two bosonic channels. Here, we remove the restriction of binary hypotheses and show that entangled photons can remarkably boost the discrimination of multiple bosonic channels. More precisely, we formulate a general problem of channel-position finding where the goal is to determine the position of a target channel among many background channels. We prove that, using entangled photons at the input and a generalized form of conditional nulling receiver at the output, we may outperform any classical strategy. Our results can be applied to enhance a range of technological tasks, including the optical readout of sparse classical data, the spectroscopic analysis of a frequency spectrum, and the determination of the direction of a target at fixed range
Giant enhancement and control of second-harmonic radiation from algaas nanoantennas
© 2017 Institute of Electrical and Electronics Engineers Inc. All Rights Reserved. We fabricate AlGaAs nanoantennas on a glass substrate and demonstrate the highest nonlinear conversion efficiency of 10-4 with the capability for shaping the radiation patterns and polarization of the second harmonic emission in both forward and backward directions. We also decode dynamic multipolar contributions to the second harmonic generation within such nanoantennas
Transition probabilities for general birth-death processes with applications in ecology, genetics, and evolution
A birth-death process is a continuous-time Markov chain that counts the
number of particles in a system over time. In the general process with
current particles, a new particle is born with instantaneous rate
and a particle dies with instantaneous rate . Currently no robust and
efficient method exists to evaluate the finite-time transition probabilities in
a general birth-death process with arbitrary birth and death rates. In this
paper, we first revisit the theory of continued fractions to obtain expressions
for the Laplace transforms of these transition probabilities and make explicit
an important derivation connecting transition probabilities and continued
fractions. We then develop an efficient algorithm for computing these
probabilities that analyzes the error associated with approximations in the
method. We demonstrate that this error-controlled method agrees with known
solutions and outperforms previous approaches to computing these probabilities.
Finally, we apply our novel method to several important problems in ecology,
evolution, and genetics
Laparoscopic nephrectomy for giant staghorn calculus with non-functioning kidneys: Is associated unsuspected urothelial carcinoma responsible for conversion? Report of 2 cases
BACKGROUND-: Neglected renal stones remain a major cause of morbidity in developing countries. They not only result in functional impairment of affected kidney, but also act as an important predisposing factor for development of urothelial neoplasms. It is not uncommon to miss an associated urothelial tumor in a patient of nephrolithiasis preoperatively. CASE PRESENTATION-: In last 3 years, we came across two patients with giant staghorn calculus and poorly functioning kidneys who underwent laparoscopic nephrectomy. In view of significant perirenal adhesions & loss of normal tissue planes both these patients were electively converted to open surgery. The pathological examination of specimen revealed an unsuspected urothelial carcinoma in both these patients. The summary of our cases and review of literature is presented. CONCLUSION-: It is important to keep a differential diagnosis of associated urothelial malignancy in mind in patient presenting with long standing renal calculi. The exact role of a computerized tomography and cytology in preoperative workup for detection of possible associated malignancy in such condition is yet to be defined. Similarly if laparoscopic dissection appears difficult during nephrectomy for a renal calculus with non-functional kidney, keeping a possibility of associated urothelial malignancy in mind it is advisable to dissect in a plane outside gerotas fascia as for radical nephrectomy
Characterizing Rhodopsin-Arrestin Interactions with the Fragment Molecular Orbital (FMO) Method
Arrestin binding to G protein-coupled receptors (GPCRs) plays a vital role in receptor signaling. Recently, the crystal structure of rhodopsin bound to activated visual arrestin was resolved using XFEL (X-ray free electron laser). However, even with the crystal structure in hand, our ability to understand GPCR-arrestin binding is limited by the availability of accurate tools to explore receptor-arrestin interactions. We applied fragment molecular orbital (FMO) method to explore the interactions formed between the residues of rhodopsin and arrestin. FMO enables ab initio approaches to be applied to systems that conventional quantum mechanical (QM) methods would be too compute-expensive. The FMO calculations detected 35 significant interactions involved in rhodopsin-arrestin binding formed by 25 residues of rhodopsin and 28 residues of arrestin. Two major regions of interaction were identified: at the C-terminal tail of rhodopsin (D330-S343) and where the "finger loop" (G69-T79) of arrestin directly inserts into rhodopsin active core. Out of these 35 interactions, 23 were mainly electrostatic and 12 hydrophobic in nature
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