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Xiaobin Lin, Yu Tang, Wei Yang, Fei Tan, Lili Lin, Xiaohua Liu, Xiaoming Feng
Although high enantioselectivity of [2,3]-sigmatropic rearrangement of sulfonium ylides (Doyle-Kirmse reaction) has proven surprisingly elusive using classic chiral Rh(II) and Cu(I) catalysts, in principle it is due to the difficulty in fine discrimination of the heterotopic lone pairs of sulfur and chirality inversion at sulfur of sulfonium ylides. Here, we show that the synergistic merger of new α-diazo pyrazoleamides and chiral N,N'-dioxide-nickel(II) complex catalyst enables a highly enantioselective Doyle-Kirmse reaction...
February 14, 2018: Journal of the American Chemical Society
Nicole Jackson, Lloyd Czaplewski, Laura J V Piddock
Antibiotic (antibacterial) resistance is a serious global problem and the need for new treatments is urgent. The current antibiotic discovery model is not delivering new agents at a rate that is sufficient to combat present levels of antibiotic resistance. This has led to fears of the arrival of a 'post-antibiotic era'. Scientific difficulties, an unfavourable regulatory climate, multiple company mergers and the low financial returns associated with antibiotic drug development have led to the withdrawal of many pharmaceutical companies from the field...
February 9, 2018: Journal of Antimicrobial Chemotherapy
Mark G Alford, Luke Bovard, Matthias Hanauske, Luciano Rezzolla, Kai Schwenzer
Inferring the properties of dense matter is one of the most exciting prospects from the measurement of gravitational waves from neutron star mergers. However, it requires reliable numerical simulations that incorporate viscous dissipation and energy transport as these can play a significant role in the survival time of the post-merger object. We calculate time scales for typical forms of dissipation and find that thermal transport and shear viscosity will not be important unless neutrino trapping occurs, which requires temperatures above 10 MeV and gradients over length scales of 0...
January 26, 2018: Physical Review Letters
Lisa M Verberne, Marijke C Kars, Sasja A Schepers, Antoinette Y N Schouten-van Meeteren, Martha A Grootenhuis, Johannes J M van Delden
BACKGROUND: Over the last decade, paediatric palliative care teams (PPCTs) have been introduced to support children with life-limiting diseases and their families and to ensure continuity, coordination and quality of paediatric palliative care (PPC). However, implementing a PPCT into an organisation is a challenge. The objective of this study was to identify barriers and facilitators reported by healthcare professionals (HCPs) in primary, secondary or tertiary care for implementing a newly initiated multidisciplinary PPCT to bridge the gap between hospital and home...
February 12, 2018: BMC Palliative Care
A Laurie W Shroyer, William E Gioia, Muath Bishawi, Amelia S Wallace, Brian C Gulack, Ying Xian, Sean M O'Brien, Vinod H Thourani, Thomas V Bilfinger
BACKGROUND: Since 2010, 460+ hospital mergers have occurred in the United States rerouting historical coronary artery bypass graft [CABG] referral patterns. The goals of this study were: 1) to compare risk-adjusted CABG outcomes between single-center versus multi-center surgeons; and 2) for multi-center surgeons, to evaluate the risk-adjusted outcomes between their home (primary) versus satellite (secondary) hospitals. METHODS: Using the Society of Thoracic Surgeons Adult Cardiac Surgery Database, non-emergent, first-time CABG procedures (n = 543,403) performed in the United States between 2011 and 2014 were extracted across 1,120 centers and for 2,676 surgeons...
February 7, 2018: Annals of Thoracic Surgery
Hannah Middleton, Siyuan Chen, Walter Del Pozzo, Alberto Sesana, Alberto Vecchio
Pulsar timing arrays are presently the only means to search for the gravitational wave stochastic background from super massive black hole binary populations, considered to be within the grasp of current or near-future observations. The stringent upper limit from the Parkes Pulsar Timing Array has been interpreted as excluding (>90% confidence) the current paradigm of binary assembly through galaxy mergers and hardening via stellar interaction, suggesting evolution is accelerated or stalled. Using Bayesian hierarchical modelling we consider implications of this upper limit for a range of astrophysical scenarios, without invoking stalling, nor more exotic physical processes...
February 8, 2018: Nature Communications
Cynthia Russo, Oriana Calo, Georgia Harrison, Kathleen Mahoney, Kathleen Evanovich Zavotsky
OBJECTIVE: The aim of this study was to explore the relationship between resilience and coping in frontline nurses working in a healthcare system that has recently undergone a merger. BACKGROUND: Hospital mergers are common in the current healthcare environment. Mergers can provide hospital nurses the opportunity to use and develop positive coping strategies to help remain resilient during times of change. METHODS: An anonymous-survey, quantitative, exploratory, descriptive study design was used...
March 2018: Clinical Nurse Specialist CNS
Sukanta Bose, Kabir Chakravarti, Luciano Rezzolla, B S Sathyaprakash, Kentaro Takami
We show how gravitational-wave observations with advanced detectors of tens to several tens of neutron-star binaries can measure the neutron-star radius with an accuracy of several to a few percent, for mass and spatial distributions that are realistic, and with none of the sources located within 100 Mpc. We achieve such an accuracy by combining measurements of the total mass from the inspiral phase with those of the compactness from the postmerger oscillation frequencies. For estimating the measurement errors of these frequencies, we utilize analytical fits to postmerger numerical relativity waveforms in the time domain, obtained here for the first time, for four nuclear-physics equations of state and a couple of values for the mass...
January 19, 2018: Physical Review Letters
B-B Zhang, B Zhang, H Sun, W-H Lei, H Gao, Y Li, L Shao, Y Zhao, Y-D Hu, H-J Lü, X-F Wu, X-L Fan, G Wang, A J Castro-Tirado, S Zhang, B-Y Yu, Y-Y Cao, E-W Liang
Double neutron star (DNS) merger events are promising candidates of short gamma-ray burst (sGRB) progenitors as well as high-frequency gravitational wave (GW) emitters. On August 17, 2017, such a coinciding event was detected by both the LIGO-Virgo gravitational wave detector network as GW170817 and Gamma-Ray Monitor on board NASA's Fermi Space Telescope as GRB 170817A. Here, we show that the fluence and spectral peak energy of this sGRB fall into the lower portion of the distributions of known sGRBs. Its peak isotropic luminosity is abnormally low...
January 31, 2018: Nature Communications
Daniel H Johansen, Juan D Sanchez-Heredia, Jan R Petersen, Tom K Johansen, Vitaliy Zhurbenko, Jan H Ardenkjaer-Larsen
Pursuing the ultimate limit of detection in magnetic resonance imaging (MRI) requires cryogenics to decrease the thermal noise of the electronic circuits. As cryogenic coils for MRI are slowly emerging cryogenic preamplifiers are required to fully exploit their potential. A cryogenic preamplifier operated at 77 K is designed and implemented for C imaging at 3 T (32.13 MHz), using off-the-shelves components. The design is based on a high electron mobility transistor (ATF54143) in a common source configuration...
February 2018: IEEE Transactions on Biomedical Circuits and Systems
Bartholomaeus Pieber, Menny Shalom, Markus Antonietti, Peter H Seeberger, Kerry Gilmore
Solid reagents, leaching catalysts, and heterogeneous photocatalysts are commonly employed in batch processes but are ill suited for continuous flow chemistry. Heterogeneous catalysts for thermal reactions are typically used in packed bed reactors that cannot be penetrated by light and thus are not suitable for photocatalytic reactions involving solids. We demonstrate that serial micro-batch reactors (SMBRs) allow for the continuous utilization of solid materials together with liquids and gases in flow. This technology was utilized to develop selective and efficient fluorination protocols using a modified graphitic carbon nitride heterogeneous catalyst instead of costly homogeneous metal polypyridyl complexes...
January 29, 2018: Angewandte Chemie
Shigeo Yasuda, Takuya Ishii, Shunsuke Takemoto, Hiroki Haruki, Hirohisa Ohmiya
Benzylation and allylation of aldehyde acyl anions were enabled by the merger of a thiazolium N-heterocyclic carbene catalyst and a palladium-bisphosphine catalyst in a synergistic manner. Owing to the mildness of the reaction conditions, various functional groups were tolerated in the substrates.
January 23, 2018: Angewandte Chemie
Dongfeng Yuan, Zhitao Gu, Guanghui Liang, Wentao Fang, Yin Li
BACKGROUND: Thymoma is frequently associated with myasthenia gravis (MG). However, whether MG is a factor for the outcome of patients with thymoma following complete thymectomy remains unknown. The aim of this study is to investigate the effect of thymoma with MG prognostic factors. METHODS: A retrospective analysis of The Chinese Alliance for Research in Thymomas (ChART) database within 1992-2012 complete cases 875 cases, 20 years follow-up data analysis thymic tumor tissue type credits and MG, Masaoka staging and prognosis, postoperative adjuvant therapy and relationship with the prognosis of surgical removal of the way...
January 20, 2018: Zhongguo Fei Ai za Zhi, Chinese Journal of Lung Cancer
Xiang Fan, P H Diamond, L Chacón
We study the evolution of the concentration field in a single eddy in the two-dimensional (2D) Cahn-Hilliard system to better understand scalar mixing processes in that system. This study extends investigations of the classic studies of flux expulsion in 2D magnetohydrodynamics and homogenization of potential vorticity in 2D fluids. Simulation results show that there are three stages in the evolution: (A) formation of a "jelly roll" pattern, for which the concentration field is constant along spirals; (B) a change in isoconcentration contour topology; and (C) formation of a target pattern, for which the isoconcentration contours follow concentric annuli...
October 2017: Physical Review. E
Ely D Kovetz
Primordial black holes (PBHs) have long been suggested as a candidate for making up some or all of the dark matter in the Universe. Most of the theoretically possible mass range for PBH dark matter has been ruled out with various null observations of expected signatures of their interaction with standard astrophysical objects. However, current constraints are significantly less robust in the 20  M_{⊙}≲M_{PBH}≲100  M_{⊙} mass window, which has received much attention recently, following the detection of merging black holes with estimated masses of ∼30  M_{⊙} by LIGO and the suggestion that these could be black holes formed in the early Universe...
September 29, 2017: Physical Review Letters
T Aumann, C A Bertulani, F Schindler, S Typel
An experimentally constrained equation of state of neutron-rich matter is fundamental for the physics of nuclei and the astrophysics of neutron stars, mergers, core-collapse supernova explosions, and the synthesis of heavy elements. To this end, we investigate the potential of constraining the density dependence of the symmetry energy close to saturation density through measurements of neutron-removal cross sections in high-energy nuclear collisions of 0.4 to 1 GeV/nucleon. We show that the sensitivity of the total neutron-removal cross section is high enough so that the required accuracy can be reached experimentally with the recent developments of new detection techniques...
December 29, 2017: Physical Review Letters
Sue Lacey Bryant, Helen Bingham, Ruth Carlyle, Alison Day, Linda Ferguson, David Stewart
This article is the fourth in a series on New Directions. The National Health Service is under pressure, challenged to meet the needs of an ageing population, whilst striving to improve standards and ensure decision making is underpinned by evidence. Health Education England is steering a new course for NHS library and knowledge services in England to ensure access to knowledge and evidence for all decision makers. Knowledge for Healthcare calls for service transformation, role redesign, greater coordination and collaboration...
January 10, 2018: Health Information and Libraries Journal
Austin B Frakt, Craig Garthwaite
No abstract text is available yet for this article.
January 9, 2018: Annals of Internal Medicine
N Giammichele, S Charpinet, G Fontaine, P Brassard, E M Green, V Van Grootel, P Bergeron, W Zong, M-A Dupret
White-dwarf stars are the end product of stellar evolution for most stars in the Universe. Their interiors bear the imprint of fundamental mechanisms that occur during stellar evolution. Moreover, they are important chronometers for dating galactic stellar populations, and their mergers with other white dwarfs now appear to be responsible for producing the type Ia supernovae that are used as standard cosmological candles. However, the internal structure of white-dwarf stars-in particular their oxygen content and the stratification of their cores-is still poorly known, because of remaining uncertainties in the physics involved in stellar modelling codes...
January 8, 2018: Nature
Jeremy Sakstein, Bhuvnesh Jain
The LIGO and VIRGO Collaborations have recently announced the detection of gravitational waves from a neutron star-neutron star merger (GW170817) and the simultaneous measurement of an optical counterpart (the γ-ray burst GRB 170817A). The close arrival time of the gravitational and electromagnetic waves limits the difference in speed of photons and gravitons to be less than about 1 part in 10^{15}. This has three important implications for cosmological scalar-tensor gravity theories that are often touted as dark energy candidates and alternatives to the Λ cold dark matter model...
December 22, 2017: Physical Review Letters
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