3,024 research outputs found
Phonon-Mediated High-Temperature Superconductivity in Few-Hydrogen Metal-Bonded Perovskite up to 54 K under Ambient Pressure
Multi-hydrogen lanthanum hydrides have shown the highest critical temperature
at 250-260 K under 170-200 GPa. However, such high pressure is a great
challenge for sample preparation and practical application. To address this
challenge, we propose a novel design strategy for high- superconductors by
constructing new few-hydrogen metal-bonded perovskite hydrides at ambient
pressure, such as , with better ductility than the well-known
multi-hydrogen, cuprate and iron-based superconductors. Based on the
Migdal-Eliashberg theory, we predict that the structurally stable
has a favorable high up to 54 K under atmospheric pressure, similar to
SmOFeAs.Comment: 6 pages, 4 figure
Quantum Cloning Machines and the Applications
No-cloning theorem is fundamental for quantum mechanics and for quantum
information science that states an unknown quantum state cannot be cloned
perfectly. However, we can try to clone a quantum state approximately with the
optimal fidelity, or instead, we can try to clone it perfectly with the largest
probability. Thus various quantum cloning machines have been designed for
different quantum information protocols. Specifically, quantum cloning machines
can be designed to analyze the security of quantum key distribution protocols
such as BB84 protocol, six-state protocol, B92 protocol and their
generalizations. Some well-known quantum cloning machines include universal
quantum cloning machine, phase-covariant cloning machine, the asymmetric
quantum cloning machine and the probabilistic quantum cloning machine etc. In
the past years, much progress has been made in studying quantum cloning
machines and their applications and implementations, both theoretically and
experimentally. In this review, we will give a complete description of those
important developments about quantum cloning and some related topics. On the
other hand, this review is self-consistent, and in particular, we try to
present some detailed formulations so that further study can be taken based on
those results.Comment: 98 pages, 12 figures, 400+ references. Physics Reports (published
online
Average Density of States in Disordered Graphene systems
In this paper, the average density of states (ADOS) with a binary alloy
disorder in disordered graphene systems are calculated based on the recursion
method. We observe an obvious resonant peak caused by interactions with
surrounding impurities and an anti-resonance dip in ADOS curves near the Dirac
point. We also find that the resonance energy (Er) and the dip position are
sensitive to the concentration of disorders (x) and their on-site potentials
(v). An linear relation, not only holds when the impurity concentration is low
but this relation can be further extended to high impurity concentration regime
with certain constraints. We also calculate the ADOS with a finite density of
vacancies and compare our results with the previous theoretical results.Comment: 10 pages, 8 figure
DiaquaÂbisÂ(5-carbÂoxy-2-propyl-1H-imidazole-4-carboxylÂato-Îş2 N 3,O 4)cadmium(II) 3.5-hydrate
In the title complex, [Cd(C8H9N2O4)2(H2O)2]·3.5H2O, the CdII is coordinated by two water molÂecules and N,O-chelated by two 5-carbÂoxy-2-propyl-1H-imidazole-4-carboxylÂate anions in a distorted octaÂhedral geometry. The two imidazole rings are oriented to each other with a dihedral angle of 75.1 (2)°. Strong O—Hâ‹ŻO hydrogen bonds between protonated and deprotonated carboxylÂate groups occur in the molÂecular structure. In the crystal structure extensive O—Hâ‹ŻO and N—Hâ‹ŻO hydrogen bonds help to stabilize the three-dimensional supraÂmolecular framework. The propyl groups of anions are disordered over two sites with refined occupancies of 0.768 (6):0.232 (6) and 0.642 (8):0.358 (8)
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Plasma Cathepsin S and Cystatin C Levels and Risk of Abdominal Aortic Aneurysm: A Randomized Population–Based Study
Background: Human abdominal aortic aneurysm (AAA) lesions contain high levels of cathepsin S (CatS), but are deficient in its inhibitor, cystatin C. Whether plasma CatS and cystatin C levels are also altered in AAA patients remains unknown. Methods and Results: Plasma samples were collected from 476 male AAA patients and 200 age–matched male controls to determine CatS and cystatin C levels by ELISA. Student's t test demonstrated higher plasma levels of total, active, and pro–CatS in AAA patients than in controls (P<0.001). ROC curve analysis confirmed higher plasma total, active, and pro–CatS levels in AAA patients than in controls (P<0.001). Logistic regression suggested that plasma total (odds ratio [OR] = 1.332), active (OR = 1.21), and pro–CatS (OR = 1.25) levels were independent AAA risk factors that associated positively with AAA (P<0.001). Plasma cystatin C levels associated significantly, but negatively, with AAA (OR = 0.356, P<0.001). Univariate correlation demonstrated that plasma total and active CatS levels correlated positively with body–mass index, diastolic blood pressure, and aortic diameter, but negatively with the lowest ankle–brachial index (ABI). Plasma cystatin C levels also correlated negatively with the lowest ABI. Multivariate linear regression showed that plasma total, active, and pro–CatS levels correlated positively with aortic diameter and negatively with the lowest ABI, whereas plasma cystatin C levels correlated negatively with aortic diameter and the lowest ABI, after adjusting for common AAA risk factors. Conclusions: Correlation of plasma CatS and cystatin C with aortic diameter and the lowest ABI suggest these serological parameters as biomarkers for human peripheral arterial diseases and AAA
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