Pulsed laser deposition (PLD) on metal substrates has recently been discovered to present an alternative method for producing highly crystalline few-layer MoS2. However, not every metal behaves in ...the same manner during film growth, and hence, it is crucial that the ability of various metals to produce crystalline MoS2 be thoroughly investigated. In this work, MoS2 was deposited on metal substrates, Al, Ag, Ni, and Cu, using a pulsed laser. Highly crystalline few-layer MoS2 was successfully grown on Ag, but is absent in Al, Ni, and Cu under specific growth conditions. This discrepancy was attributed to either excessively strong or insufficient adlayer–substrate interactions. In the case of Al, the effects of the strong interface interactions can be offset by increasing the amount of source atoms supplied, thereby producing semicrystalline few-layer MoS2. The results show that despite PLD being a physical vapor deposition technique, both physical and chemical processes play an important role in MoS2 growth on metal substrates.
We report on Fermi/Large Area Telescope observations of the accreting black hole low-mass X-ray binary V404 Cygni during its outburst in 2015 June–July. Detailed analyses reveal a possible excess of ...γ-ray emission on 2015 26 June, with a very soft spectrum above 100 MeV, at a position consistent with the direction of V404 Cyg (within the 95 per cent confidence region and a chance probability of 4 × 10−4). This emission cannot be associated with any previously known Fermi source. Its temporal coincidence with the brightest radio and hard X-ray flare in the light curve of V404 Cyg, at the end of the main active phase of its outburst, strengthens the association with V404 Cyg. If the γ-ray emission is associated with V404 Cyg, the simultaneous detection of 511 keV annihilation emission by INTEGRAL reqires that the high-energy γ-rays originate away from the corona, possibly in a Blandford–Znajek jet. The data give support to models involving a magnetically arrested disc where a bright γ-ray jet can re-form after the occurrence of a major transient ejection seen in the radio.
By combining DNA nanotechnology and high-bandwidth single-molecule detection in nanopipets, we demonstrate an electric, label-free hybridization sensor for short DNA sequences (<100 nucleotides). ...Such short fragments are known to occur as circulating cell-free DNA in various bodily fluids, such as blood plasma and saliva, and have been identified as disease markers for cancer and infectious diseases. To this end, we use as a model system an 88-mer target from the RV1910c gene in Mycobacterium tuberculosis, which is associated with antibiotic (isoniazid) resistance in TB. Upon binding to short probes attached to long carrier DNA, we show that resistive-pulse sensing in nanopipets is capable of identifying rather subtle structural differences, such as the hybridization state of the probes, in a statistically robust manner. With significant potential toward multiplexing and high-throughput analysis, our study points toward a new, single-molecule DNA-assay technology that is fast, easy to use, and compatible with point-of-care environments.
Atomically thin tungsten disulfide (WS2) has attracted much attention in recent years due its indirect-to-direct band gap transition, band gap tunability, and giant spin splitting. However, the ...fabrication of atomically thin WS2 remains largely underdeveloped in comparison to its structural analogue MoS2. Here we report the direct fabrication of highly crystalline few-layer WS2 on silver substrates by pulse laser deposition at the relatively low temperature of 450 °C. The growth takes places by conventional epitaxy, through the in-situ formation of nearly lattice-matching Ag2S on the silver surface. Intriguingly, it was observed that the resulting film was composed of not only the usual semiconducting 2H-WS2 structure but also the less common metallic 1T-WS2. Modifications of the synthesis parameters allow for control over the crystalline quality, film thickness and crystal phase composition of the resulting WS2 film.
There has been a growing interest in better understanding the trends and determinants of health tourism activities. While much of the expanding literature on health tourism offers theoretical or ...qualitative discussion, empirical evidences has been lacking. This study employs Canada's outbound health tourism activities as an example to examine the trends in health tourism and its association with changing domestic health care market characteristics. A time-series model that accounts for potential structural changes in the trend is employed to analyze the quarterly health-related travel spending series reported in the Balance of Payments Statistics (BOPS) during 1970–2010 (n = 156). We identified a structural shift point which marks the start of an accelerated growth of health tourism and a flattened seasonality in such activities. We found that the health tourism activities of Canadian consumers increase when the private investment in medical facilities declines or when the private MPI increases during the years following the structural-change. We discussed the possible linkage of the structural shift to the General Agreement on Trade in Services (GATS), which went into effect in January, 1995.
•This study examines seasonal data on health-related travel spending by Canada.•A structural shift in health tourism took place around the time of GATS inception in 1995.•The growth in health tourism accelerated during the post-break period.•Health tourism became less seasonal after the structural break.•Health tourism responded to changes in domestic private health sector during the post-break period.
Context. Earth and outer planets are known to produce intense non-thermal radio emissions through a mechanism known as cyclotron maser instability (CMI), requiring the presence of accelerated ...electrons generally arising from magnetospheric current systems. In return, radio emissions are a good probe of these current systems and acceleration processes. The CMI generates highly anisotropic emissions and leads to important visibility effects, which have to be taken into account when interpreting the data. Several studies have shown that modelling the radio source anisotropic beaming pattern can reveal a wealth of physical information about the planetary or exoplanetary magnetospheres that produce these emissions. Aims. We present a numerical tool, called ExPRES (Exoplanetary and Planetary Radio Emission Simulator), which is able to reproduce the occurrence in a time-frequency plane of R−X CMI-generated radio emissions from planetary magnetospheres, exoplanets, or star–planet interacting systems. Special attention is given to the computation of the radio emission beaming at and near its source. Methods. We explain what physical information about the system can be drawn from such radio observations, and how it is obtained. This information may include the location and dynamics of the radio sources, the type of current system leading to electron acceleration and their energy, and, for exoplanetary systems, the orbital period of the emitting body and the strength, rotation period, tilt, and the offset of the planetary magnetic field. Most of these parameters can only be remotely measured via radio observations. Results. The ExPRES code provides the proper framework of analysis and interpretation for past, current, and future observations of planetary radio emissions, as well as for future detection of radio emissions from exoplanetary systems (or magnetic, white dwarf–planet or white dwarf–brown dwarf systems). Our methodology can be easily adapted to simulate specific observations once effective detection is achieved.
Nitrogen-doped carbon microspheres (NCSs) were fabricated via a simple, fast and energy-saving microwave-assisted method followed by thermal treatment under an ammonia atmosphere. NCSs thermally ...treated at different temperatures were investigated as anode materials for lithium ion batteries (LIBs). The results show that NCSs treated at 900 °C exhibit a maximum reversible capacity of 816 mA h g(-1) at a current density of 50 mA g(-1) and preserve a capacity of 660 mA h g(-1) after 50 cycles, and even at a high current density of 1000 mA g(-1), a capacity of 255 mA h g(-1) is maintained. The excellent electrochemical performance of NCSs is due to their porous structure and nitrogen-doping. The present NCSs should be promising low-cost anode materials with a high capacity and good cycle stability for LIBs.
Genetic variants of the two adjacent genes, IL13 and IL4 have frequently been reported as being associated with susceptibility to atopy and asthma, both in adults and children, and some studies also ...suggest association with lung function and chronic obstructive pulmonary disease. In this study, we examined for the first time the effect of these variants in 2918 adults in a longitudinal birth cohort, the British National Survey of Health and Development, where there are extensive life style, developmental and environmental data. We examine two IL13 single nucleotide polymorphisms (SNPs) IL13 rs20541 (R110Q) and rs1800925 (-1024C>T) and one IL4 SNP, rs2070874 (-33C>T) with likely function. We show that IL13 rs20541 and rs1800925 are each significantly associated with self-reported asthma and allergy, and that this association is not confounded by any of the known developmental and environmental risk factors for asthma and atopy, including in particular place of birth. IL13 rs20541 does however act as a confounder for the IL13 rs1800925 associations, meaning that there is no statistical support for rs1800925 having an independent effect. There is nevertheless evidence for interaction between smoking and rs1800925, with allergy as outcome. None of the SNPs showed association with measures of lung function, nor any interaction with the effect of smoking on lung function. In a longitudinal population cohort we have established a role for polymorphism of IL13 in determining susceptibility to both atopy and asthma.
Hypertrophic scars occur following cutaneous wounding and result in severe functional and esthetic defects. The pathophysiology of this process remains unknown. Here, we demonstrate for the first ...time that mechanical stress applied to a healing wound is sufficient to produce hypertrophic scars in mice. The resulting scars are histopathologically identical to human hypertrophic scars and persist for more than six months following a brief (one-week) period of augmented mechanical stress during the proliferative phase of wound healing. Resulting scars are structurally identical to human hypertrophic scars and showed dramatic increases in volume (20-fold) and cellular density (20-fold). The increased cellularity is accompanied by a four-fold decrease in cellular apoptosis and increased activation of the prosurvival marker Akt. To clarify the importance of apoptosis in hypertrophic scar formation, we examine the effects of mechanical loading on cutaneous wounds of animals with altered pathways of cellular apoptosis. In p53-null mice, with down-regulated cellular apoptosis, we observe significantly greater scar hypertrophy and cellular density. Conversely, scar hypertrophy and cellular density are significantly reduced in proapoptotic BclII-null mice. We conclude that mechanical loading early in the proliferative phase of wound healing produces hypertrophic scars by inhibiting cellular apoptosis through an Akt-dependent mechanism.--Aarabi, S., Bhatt, K. A., Shi, Y., Paterno, J., Chang, E. I., Loh, S. A., Holmes, J. W., Longaker, M. T., Yee, H., Gurtner, G. C. Mechanical load initiates hypertrophic scar formation through decreased cellular apoptosis.
PDF
