1,391 research outputs found
Understanding the magnetic resonance spectrum of nitrogen vacancy centers in an ensemble of randomly-oriented nanodiamonds
Nanodiamonds containing nitrogen vacancy (NV-) centers show promise for a
number of emerging applications including targeted in vivo imaging and
generating nuclear spin hyperpolarization for enhanced NMR spectroscopy and
imaging. Here, we develop a detailed understanding of the magnetic resonance
behavior of NV- centers in an ensemble of nanodiamonds with random crystal
orientations. Two-dimensional optically detected magnetic resonance
spectroscopy reveals the distribution of energy levels, spin populations, and
transition probabilities that give rise to a complex spectrum. We identify
overtone transitions that are inherently insensitive to crystal orientation and
give well-defined transition frequencies that access the entire nanodiamond
ensemble. These transitions may be harnessed for high-resolution imaging and
generation of nuclear spin hyperpolarization. The data are well described by
numerical simulations from the zero- to high-field regimes, including the
intermediate regime of maximum complexity. We evaluate the prospects of
nanodiamond ensembles specifically for nuclear hyperpolarization and show that
frequency-swept dynamic nuclear polarization may transfer a large amount of the
NV- center's hyperpolarization to nuclear spins by sweeping over a small region
of its spectrum.Comment: 6 pages, 5 figure
High Morbidity during Treatment and Residual Pulmonary Disability in Pulmonary Tuberculosis: Under-Recognised Phenomena
BACKGROUND In pulmonary tuberculosis (PTB), morbidity during treatment and residual pulmonary disability can be under-estimated. METHODS Among adults with smear-positive PTB at an outpatient clinic in Papua, Indonesia, we assessed morbidity at baseline and during treatment, and 6-month residual disability, by measuring functional capacity (six-minute walk test [6MWT] and pulmonary function), quality of life (St George's Respiratory Questionnaire [SGRQ]) and Adverse Events ([AE]: new symptoms not present at outset). Results were compared with findings in locally-recruited volunteers. RESULTS 200 PTB patients and 40 volunteers were enrolled. 6WMT was 497m (interquartile range 460-529) in controls versus 408m (IQR 346-450) in PTB patients at baseline (p<0.0001) and 470m (IQR 418-515) in PTB patients after 6 months (p=0.02 versus controls). SGRQ total score was 0 units (IQR 0-2.9) in controls, versus 36.9 (27.4-52.8) in PTB patients at baseline (p<0.0001) and 4.3 (1.7-8.8) by 6 months (p<0.0001). Mean percentage of predicted FEV1 was 92% (standard deviation 19.9) in controls, versus 63% (19.4) in PTB patients at baseline (p<0.0001) and 71% (17.5) by 6 months (p<0.0001). After 6 months, 27% of TB patients still had at least moderate-severe pulmonary function impairment, and 57% still had respiratory symptoms, despite most achieving 'successful' treatment outcomes, and reporting good quality of life. More-advanced disease at baseline (longer illness duration, worse baseline X-ray) and HIV positivity predicted residual disability. AE at any time during treatment were common: itch 59%, arthralgia 58%, headache 40%, nausea 33%, vomiting 16%. CONCLUSION We found high 6-month residual pulmonary disability and high AE rates. Although PTB treatment is highly successful, the extent of morbidity during treatment and residual impairment could be overlooked if not specifically sought. Calculations of PTB-related burden of disease should acknowledge that TB-related morbidity does not stop at 6 months. Early case detection and treatment are key in minimising residual impairment.The study received funding from the Australian Respiratory Council, Royal Australasian College of Physicians (Covance Award to APR), National
Health and Medical Research Council (NHMRC) of Australia (Grants 605806 and 496600, a scholarship to APR, and fellowships to APR, TWY, PMK,
NMA). Graeme Maguire is supported by an NHMRC Practitioner Fellowship and the Margaret Ross Chair in Indigenous Health. Views expressed in this
publication are those of the authors and do not reflect the views of NHMRC. The funders had no role in study design, data collection and analysis, decision
to publish, or preparation of the manuscript
Scrub typhus in the Northern Territory: exceeding the boundaries of Litchfield National Park
Scrub typhus is recognised as an important differential diagnosis of fever, rash and sepsis in patients with a history of travel to Litchfield National Park in the Top End of the Northern Territory. All confirmed scrub typhus cases to date from the Northern Territory have visited the Park, but the presence of similar rainforest pockets elsewhere in the Top End suggested further infectious locations might be identified with increased tourism. We report a cse of serologically confirmed Orientia tsutsugamushi infectiou in a man who had not been within Litchfield Park, but had visited another discrete Top End rainforest area
Optimizing aerosolization of a high-dose L-arginine powder for pulmonary delivery
In this study a carrier-free dry powder inhalation (DPI) containing L-arginine (ARG) was developed. As such, it is proposed that ARG could be used for adjunctive treatment of cystic fibrosis and/or tuberculosis. Various processing methods were used to manufacture high-dose formulation batches consisting various amounts of ARG and excipients. The formulations were evaluated using several analytical methods to assess suitability for further investigation. Several batches had enhanced in vitro aerolization properties. Significant future challenges include the highly hygroscopic nature of unformulated ARG powder and identifying the scale of dose of ARG required to achieve the response in lungs
Predictions for the X-ray circumgalactic medium of edge-on discs and spheroids
We investigate how the X-ray circumgalactic medium (CGM) of present-day
galaxies depends on galaxy morphology and azimuthal angle using mock
observations generated from the EAGLE cosmological hydrodynamic simulation. By
creating mock stacks of {\it eROSITA}-observed galaxies oriented to be edge-on,
we make several observationally-testable predictions for galaxies in the
stellar mass range M. The soft X-ray CGM of
disc galaxies is between 60 and 100\% brighter along the semi-major axis
compared to the semi-minor axis, between 10-30 kpc. This azimuthal dependence
is a consequence of the hot ( K) CGM being non-spherical: specifically
it is flattened along the minor axis such that denser and more luminous gas
resides in the disc plane and co-rotates with the galaxy. Outflows enrich and
heat the CGM preferentially perpendicular to the disc, but we do not find an
observationally-detectable signature along the semi-minor axis. Spheroidal
galaxies have hotter CGMs than disc galaxies related to spheroids residing at
higher halos masses, which may be measurable through hardness ratios spanning
the keV band. While spheroids appear to have brighter CGMs than discs
for the selected fixed bin, this owes to spheroids having higher
stellar and halo masses within that bin, and obscures the fact that
both simulated populations have similar total CGM luminosities at the exact
same . Discs have brighter emission inside 20 kpc and more steeply
declining profiles with radius than spheroids. We predict that the {\it
eROSITA} 4-year all-sky survey should detect many of the signatures we predict
here, although targeted follow-up observations of highly inclined nearby discs
after the survey may be necessary to observe some of our azimuthally-dependent
predictions.Comment: 12 pages, 11 figures, 1 table. Submitted to MNRAS. Comments welcom
An electroluminescent and tunable cavity-enhanced carbon-nanotube-emitter in the telecom band
Emerging photonic information processing systems require chip-level integration of controllable nanoscale light sources at telecommunication wavelengths. Currently, substantial challenges remain in the dynamic control of the sources, the low-loss integration into a photonic environment, and in the site-selective placement at desired positions on a chip. Here, we overcome these challenges using heterogeneous integration of electroluminescent (EL), semiconducting carbon nanotubes (sCNTs) into hybrid two dimensional – three dimensional (2D-3D) photonic circuits. We demonstrate enhanced spectral line shaping of the EL sCNT emission. By back-gating the sCNT-nanoemitter we achieve full electrical dynamic control of the EL sCNT emission with high on-off ratio and strong enhancement in the telecommunication band. Using nanographene as a low-loss material to electrically contact sCNT emitters directly within a photonic crystal cavity enables highly efficient EL coupling without compromising the optical quality of the cavity. Our versatile approach paves the way for controllable integrated photonic circuits
Salivaricin G32, a Homolog of the Prototype Streptococcus pyogenes
Salivaricin G32, a 2667 Da novel member of the SA-FF22 cluster of lantibiotics, has been purified and characterized from Streptococcus salivarius strain G32. The inhibitory peptide differs from the Streptococcus pyogenes—produced SA-FF22 in the absence of lysine in position 2. The salivaricin G32 locus was widely distributed in BLIS-producing S. salivarius, with 6 (23%) of 26 strains PCR-positive for the structural gene, slnA. As for most other lantibiotics produced by S. salivarius, the salivaricin G32 locus can be megaplasmid encoded. Another member of the SA-FF22 family was detected in two Streptococcus dysgalactiae of bovine origin, an observation supportive of widespread distribution of this lantibiotic within the genus Streptococcus. Since the inhibitory spectrum of salivaricin G32 includes Streptococcus pyogenes, its production by S. salivarius, either as a member of the normal oral microflora or as a commercial probiotic, could serve to enhance protection of the human host against S. pyogenes infection
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