Development of Magnetic Field-enhanced Vacuum Arc Deposition in China

This paper reviews the latest research and development in China for magnetic field-enhanced vacuum arc deposition (MFE-VAD). China has developed some new technologies in MFE-VAD. These technologies are all based on the interaction between the magnetic field and cathode arc spot (and arc plasma). An external magnetic field can be applied to steer the cathode spot motion including axisymmetric magnetic field (AMF), transverse rotating magnetic field (TRMF) and coupling magnetic field (CMF). The transverse component of AFM can accelerate the cathode spot motion. The TRMF covered the whole cathode was generated by stationary three-phase windings carrying three-phase alternating currents. The CMF was designed to improve the increasing of plasma density and the collisions between ion and droplet-particls (DPs) charging, and as well as further purify the DPs

A study of randomness, correlations and collectivity in the nuclear shell model

A variable combination of realistic and random two-body interactions allows the study of collective properties, such as the energy spectra and B(E2) transition strengths in 44Ti, 48Cr and 24Mg. It is found that the average energies of the yrast band states maintain the ordering for any degree of randomness, but the B(E2) values lose their quadrupole collectivity when randomness dominates the Hamiltonian. The high probability of the yrast band to be ordered in the presence of pure random forces exhibits the strong correlations between the different members of the band.Comment: 8 pages, 10 figures, 8 tables, submitted to Physical Review

Time--Distance Helioseismology Data Analysis Pipeline for Helioseismic and Magnetic Imager onboard Solar Dynamics Observatory (SDO/HMI) and Its Initial Results

The Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory (SDO/HMI) provides continuous full-disk observations of solar oscillations. We develop a data-analysis pipeline based on the time-distance helioseismology method to measure acoustic travel times using HMI Doppler-shift observations, and infer solar interior properties by inverting these measurements. The pipeline is used for routine production of near-real-time full-disk maps of subsurface wave-speed perturbations and horizontal flow velocities for depths ranging from 0 to 20 Mm, every eight hours. In addition, Carrington synoptic maps for the subsurface properties are made from these full-disk maps. The pipeline can also be used for selected target areas and time periods. We explain details of the pipeline organization and procedures, including processing of the HMI Doppler observations, measurements of the travel times, inversions, and constructions of the full-disk and synoptic maps. Some initial results from the pipeline, including full-disk flow maps, sunspot subsurface flow fields, and the interior rotation and meridional flow speeds, are presented.Comment: Accepted by Solar Physics topical issue 'Solar Dynamics Observatory

Melting behavior of ultrathin titanium nanowires

The thermal stability and melting behavior of ultrathin titanium nanowires with multi-shell cylindrical structures are studied using molecular dynamic simulation. The melting temperatures of titanium nanowires show remarkable dependence on wire sizes and structures. For the nanowire thinner than 1.2 nm, there is no clear characteristic of first-order phase transition during the melting, implying a coexistence of solid and liquid phases due to finite size effect. An interesting structural transformation from helical multi-shell cylindrical to bulk-like rectangular is observed in the melting process of a thicker hexagonal nanowire with 1.7 nm diameter.Comment: 4 pages, 4 figure

Tests of the random phase approximation for transition strengths

We investigate the reliability of transition strengths computed in the random-phase approximation (RPA), comparing with exact results from diagonalization in full $0\hbar\omega$ shell-model spaces. The RPA and shell-model results are in reasonable agreement for most transitions; however some very low-lying collective transitions, such as isoscalar quadrupole, are in serious disagreement. We suggest the failure lies with incomplete restoration of broken symmetries in the RPA. Furthermore we prove, analytically and numerically, that standard statements regarding the energy-weighted sum rule in the RPA do not hold if an exact symmetry is broken.Comment: 11 pages, 7 figures; Appendix added with new proof regarding violation of energy-weighted sum rul

Enterotypes of the human gut mycobiome

BACKGROUND: The fungal component of the human gut microbiome, also known as the mycobiome, plays a vital role in intestinal ecology and human health. However, the overall structure of the gut mycobiome as well as the inter-individual variations in fungal composition remains largely unknown. In this study, we collected a total of 3363 fungal sequencing samples from 16 cohorts across three continents, including 572 newly profiled samples from China. RESULTS: We identify and characterize four mycobiome enterotypes using ITS profiling of 3363 samples from 16 cohorts. These enterotypes exhibit stability across populations and geographical locations and significant correlation with bacterial enterotypes. Particularly, we notice that fungal enterotypes have a strong age preference, where the enterotype dominated by Candida (i.e., Can_type enterotype) is enriched in the elderly population and confers an increased risk of multiple diseases associated with a compromised intestinal barrier. In addition, bidirectional mediation analysis reveals that the fungi-contributed aerobic respiration pathway associated with the Can_type enterotype might mediate the association between the compromised intestinal barrier and aging. CONCLUSIONS: We show that the human gut mycobiome has stable compositional patterns across individuals and significantly correlates with multiple host factors, such as diseases and host age. Video Abstract

Subtelomeric assembly of a multi-gene pathway for antimicrobial defense compounds in cereals

Non-random gene organization in eukaryotes plays a significant role in genome evolution. Here, we investigate the origin of a biosynthetic gene cluster for production of defence compounds in oat—the avenacin cluster. We elucidate the structure and organisation of this 12-gene cluster, characterise the last two missing pathway steps, and reconstitute the entire pathway in tobacco by transient expression. We show that the cluster has formed de novo since the divergence of oats in a subtelomeric region of the genome that lacks homology with other grasses, and that gene order is approximately colinear with the biosynthetic pathway. We speculate that the positioning of the late pathway genes furthest away from the telomere may mitigate against a ‘self-poisoning’ scenario in which toxic intermediates accumulate as a result of telomeric gene deletions. Our investigations reveal a striking example of adaptive evolution underpinned by remarkable genome plasticity

Prioritisation of Anti-SARS-Cov-2 Drug Repurposing Opportunities Based on Plasma and Target Site Concentrations Derived from their Established Human Pharmacokinetics.

There is a rapidly expanding literature on the in vitro antiviral activity of drugs that may be repurposed for therapy or chemoprophylaxis against SARS-CoV-2. However, this has not been accompanied by a comprehensive evaluation of the target plasma and lung concentrations of these drugs following approved dosing in humans. Accordingly, EC90 values recalculated from in vitro anti-SARS-CoV-2 activity data was expressed as a ratio to the achievable maximum plasma concentrations (Cmax) at an approved dose in humans (Cmax/EC90 ratio). Only 14 of the 56 analysed drugs achieved a Cmax/EC90 ratio above 1. A more in-depth assessment demonstrated that only nitazoxanide, nelfinavir, tipranavir (ritonavir-boosted) and sulfadoxine achieved plasma concentrations above their reported anti-SARS-CoV-2 activity across their entire approved dosing interval. An unbound lung to plasma tissue partition coefficient (Kp Ulung ) was also simulated to derive a lung Cmax/EC50 as a better indicator of potential human efficacy. Hydroxychloroquine, chloroquine, mefloquine, atazanavir (ritonavir-boosted), tipranavir (ritonavir-boosted), ivermectin, azithromycin and lopinavir (ritonavir-boosted) were all predicted to achieve lung concentrations over 10-fold higher than their reported EC50 . Nitazoxanide and sulfadoxine also exceeded their reported EC50 by 7.8- and 1.5-fold in lung, respectively. This analysis may be used to select potential candidates for further clinical testing, while deprioritising compounds unlikely to attain target concentrations for antiviral activity. Future studies should focus on EC90 values and discuss findings in the context of achievable exposures in humans, especially within target compartments such as the lung, in order to maximise the potential for success of proposed human clinical trials

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters