Non-Planar Geometrical Effects on the Magnetoelectrical Signal in a Three-Dimensional Nanomagnetic Circuit.

Expanding nanomagnetism and spintronics into three dimensions (3D) offers great opportunities for both fundamental and technological studies. However, probing the influence of complex 3D geometries on magnetoelectrical phenomena poses important experimental and theoretical challenges. In this work, we investigate the magnetoelectrical signals of a ferromagnetic 3D nanodevice integrated into a microelectronic circuit using direct-write nanofabrication. Due to the 3D vectorial nature of both electrical current and magnetization, a complex superposition of several magnetoelectrical effects takes place. By performing electrical measurements under the application of 3D magnetic fields, in combination with macrospin simulations and finite element modeling, we disentangle the superimposed effects, finding how a 3D geometry leads to unusual angular dependences of well-known magnetotransport effects such as the anomalous Hall effect. Crucially, our analysis also reveals a strong role of the noncollinear demagnetizing fields intrinsic to 3D nanostructures, which results in an angular dependent magnon magnetoresistance contributing strongly to the total magnetoelectrical signal. These findings are key to the understanding of 3D spintronic systems and underpin further fundamental and device-based studies.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus isolates in New South Wales, Australia, 2012-2017.

BACKGROUND: To better understand the molecular epidemiology of MRSA and to assess the utility of 19-target binary typing we undertook large-scale epidemiological surveillance of MRSA from invasive and non-invasive clinical specimens, and screening swabs. METHODS: Binary typing was performed on clinical MRSA isolates collected in New South Wales (NSW), Australia between 01/01/2012 - 31/12/2017. Binary type (BT) predicted multilocus sequence type (ST) and spa types based on results from isolates which had been characterised by both methods. RESULTS: 7624 MRSA isolates were analysed of which 3581 (47%) were wounds or skin & softtissue isolates (W/SSTI), 2436 (32%) screening swabs, 469 (6%) blood cultures (BC), 780 (10%) others, and 358 (5%) unknown. We identified 731 BTs, 54 spa types, and 31 STs. ST239 was the commonest MRSA clone in 2012 (30%), but it decreased to 7% in 2017 (p <0.001). In contrast, <0.5% of MRSA were ST45 in 2012 compared to 14% in 2017 (p<0.001). An emergence of PVL-positive ST22 was also noted. Of all isolates, 28% (2122/7624) were lukS/PVL positive; the proportion, among prospectively collected isolates increased from 24% (1406/5858) to 33% (1933/5858) between 2012 and 2017 (p <0.0001). 43% (1534/3581) W/SSTI, 20% (95/469) BC and 10% (239/2436) screening swabs were PVL-positive. CONCLUSIONS: A major change in the epidemiology of MRSA was noted with a decline of ST239, an emergence of ST45 and PVL-positive ST22, and a significant increase in PVL-positive isolates. Binary typing can be a useful routine laboratory test for prospective molecular surveillance of MRSA colonisation and infection.

Relentless spread and adaptation of non-typeable vanA vancomycin-resistant Enterococcus faecium: a genome-wide investigation.

Background: VRE are prevalent among patients in ICUs. Non-typeable vanA VRE, due to loss of one of the genes used for MLST (pstS), have increased in Australia, suggestive of a new, hospital-acquired lineage. Objectives: To understand the significance of this lineage and its transmission using WGS of strains isolated from patients in ICUs across New South Wales, Australia. Methods: A total of 240 Enterococcus faecium isolates collected between February and May 2016, and identified by conventional PCR as vanA positive, were sequenced. Isolates originated from 12 ICUs in New South Wales, grouped according to six local health districts, and represented both rectal screening swab (n = 229) and clinical (n = 11) isolates. Results: ST analysis revealed the absence of the pstS gene in 84.2% (202 of 240) of vanA isolates. Two different non-typeable STs were present based on different allelic backbone patterns. Loss of the pstS gene appeared to be the result of multiple recombination events across this region. Evidence for pstS-negative lineage spread across all six local health districts was observed suggestive of inter-hospital transmission. In addition, multiple outbreaks were detected, some of which were protracted and lasted for the duration of the study. Conclusions: These findings confirmed the evolution, emergence and dissemination of non-typeable vanA E. faecium. This study has highlighted the utility of WGS when attempting to describe accurately the hospital-based pathogen epidemiology, which in turn will continue to inform optimal infection control measures necessary to halt the spread of this important nosocomial organism.

Aviation and global climate change in the 21st century.

Aviation emissions contribute to the radiative forcing (RF) of climate. Of importance are emissions of carbon dioxide (CO2), nitrogen oxides (NO x ), aerosols and their precursors (soot and sulphate), and increased cloudiness in the form of persistent linear contrails and induced-cirrus cloudiness. The recent Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) quantified aviation's RF contribution for 2005 based upon 2000 operations data. Aviation has grown strongly over the past years, despite world-changing events in the early 2000s; the average annual passenger traffic growth rate was 5.3% yr-1 between 2000 and 2007, resulting in an increase of passenger traffic of 38%. Presented here are updated values of aviation RF for 2005 based upon new operations data that show an increase in traffic of 22.5%, fuel use of 8.4% and total aviation RF of 14% (excluding induced-cirrus enhancement) over the period 2000-2005. The lack of physical process models and adequate observational data for aviation-induced cirrus effects limit confidence in quantifying their RF contribution. Total aviation RF (excluding induced cirrus) in 2005 was ∼55 mW m-2 (23-87 mW m-2, 90% likelihood range), which was 3.5% (range 1.3-10%, 90% likelihood range) of total anthropogenic forcing. Including estimates for aviation-induced cirrus RF increases the total aviation RF in 2005-78 mW m-2 (38-139 mW m-2, 90% likelihood range), which represents 4.9% of total anthropogenic forcing (2-14%, 90% likelihood range). Future scenarios of aviation emissions for 2050 that are consistent with IPCC SRES A1 and B2 scenario assumptions have been presented that show an increase of fuel usage by factors of 2.7-3.9 over 2000. Simplified calculations of total aviation RF in 2050 indicate increases by factors of 3.0-4.0 over the 2000 value, representing 4-4.7% of total RF (excluding induced cirrus). An examination of a range of future technological options shows that substantive reductions in aviation fuel usage are possible only with the introduction of radical technologies. Incorporation of aviation into an emissions trading system offers the potential for overall (i.e., beyond the aviation sector) CO2 emissions reductions. Proposals exist for introduction of such a system at a European level, but no agreement has been reached at a global level.