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Silver nitrate cautery and bipolar electrocautery are commonly used in the treatment of epistaxis. Currently, there are no recommendations on optimum contact times or power for nasal cautery. ENT consultant practice in the UK has not previously been evaluated.
This study examined the burn depth associated with silver nitrate (75 per cent concentration) cautery and bipolar electrocautery on porcine septum samples, using varying contact times and power. ENT consultants completed a survey evaluating their practice.
Results and conclusion
ENT consultant practice of nasal cautery was shown to vary widely. Silver nitrate cautery with a contact time of less than 30 seconds does not cause a full thickness burn. The findings lend some support to bilateral cauterisation with silver nitrate. Bipolar electrocautery should be set at lower than 10 W and with a contact time of less than 4 seconds to reduce the risk of complications associated with a full thickness burn.
Interest in electronic hand hygiene monitoring systems (EHHMSs) is now widespread throughout the infection control community. We tested 2 types of EHHMS for accuracy. The type B EHHMS captured more HH events with superior accuracy. Hospitals considering an EHHMS should assess the technology’s ability to accurately capture HH performance in the clinical workflow.
After a population of laser-driven hot electrons traverses a limited thickness solid target, these electrons will encounter the rear surface, creating TV/m fields that heavily influence the subsequent hot-electron propagation. Electrons that fail to overcome the electrostatic potential reflux back into the target. Those electrons that do overcome the field will escape the target. Here, using the particle-in-cell (PIC) code EPOCH and particle tracking of a large population of macro-particles, we investigate the refluxing and escaping electron populations, as well as the magnitude, spatial and temporal evolution of the rear surface electrostatic fields. The temperature of both the escaping and refluxing electrons is reduced by 30%–50% when compared to the initial hot-electron temperature as a function of intensity between
. Using particle tracking we conclude that the highest energy internal hot electrons are guaranteed to escape up to a threshold energy, below which only a small fraction are able to escape the target. We also examine the temporal characteristic of energy changes of the refluxing and escaping electrons and show that the majority of the energy change is as a result of the temporally evolving electric field that forms on the rear surface.
Laser–solid interactions are highly suited as a potential source of high energy X-rays for nondestructive imaging. A bright, energetic X-ray pulse can be driven from a small source, making it ideal for high resolution X-ray radiography. By limiting the lateral dimensions of the target we are able to confine the region over which X-rays are produced, enabling imaging with enhanced resolution and contrast. Using constrained targets we demonstrate experimentally a
X-ray source, improving the image quality compared to unconstrained foil targets. Modelling demonstrates that a larger sheath field envelope around the perimeter of the constrained targets increases the proportion of electron current that recirculates through the target, driving a brighter source of X-rays.
Clostridium difficile, the most common cause of hospital-associated diarrhoea in developed countries, presents major public health challenges. The high clinical and economic burden from C. difficile infection (CDI) relates to the high frequency of recurrent infections caused by either the same or different strains of C. difficile. An interval of 8 weeks after index infection is commonly used to classify recurrent CDI episodes. We assessed strains of C. difficile in a sample of patients with recurrent CDI in Western Australia from October 2011 to July 2017. The performance of different intervals between initial and subsequent episodes of CDI was investigated. Of 4612 patients with CDI, 1471 (32%) were identified with recurrence. PCR ribotyping data were available for initial and recurrent episodes for 551 patients. Relapse (recurrence with same ribotype (RT) as index episode) was found in 350 (64%) patients and reinfection (recurrence with new RT) in 201 (36%) patients. Our analysis indicates that 8- and 20-week intervals failed to adequately distinguish reinfection from relapse. In addition, living in a non-metropolitan area modified the effect of age on the risk of relapse. Where molecular epidemiological data are not available, we suggest that applying an 8-week interval to define recurrent CDI requires more consideration.
This paper reviews several procedures for the removal of instrumental contributions from measured x-ray diffraction profiles, including: direct convolution, unconstrained and constrained deconvolution, an iterative technique, and a maximum entropy method (MEM) which we have adapted to x-ray diffraction profile analysis. Decorevolutions using the maximum entropy approach were found to be the most robust with simulated profiles which included Poisson-distributed noise and uncertainties in the instrument profile function (IPF). The MEM procedure is illustrated by application to the analysis for domain size and microstrain carried out on the four calcined α-alumina candidate materials for Standard Reference Material (SRM) 676 (a quantitative analysis standard for I/Ic determinations), along with the certified material. Williamson-Hall plots of these data were problematic with respect to interpretation of the microstrain, indicating that the line profile standard, SRM 660 (LaB6), exhibits a small amount of strain broadening, particularly at high 2θ angle. The domain sizes for all but one of the test materials were much smaller than the crystallite (particle) size; indicating the presence of low angle grain boundaries.
As a technique for non-destructive materials analysis, computed tomography (CT) has been especially useful for studying the dependence of the structure of ceramics on manufacturing processes. CT also has been used for characterizing the lithology of reservoir cores while they are still contained in preservation material or a core barrel.
The parameter measured by CT is the X-ray attenuation coefficient, which is a function of both material density and material composition.
A multichannel calorimeter system is designed and constructed which is capable of delivering single-shot and broad-band spectral measurement of terahertz (THz) radiation generated in intense laser–plasma interactions. The generation mechanism of backward THz radiation (BTR) is studied by using the multichannel calorimeter system in an intense picosecond laser–solid interaction experiment. The dependence of the BTR energy and spectrum on laser energy, target thickness and pre-plasma scale length is obtained. These results indicate that coherent transition radiation is responsible for the low-frequency component (
1 THz) of BTR. It is also observed that a large-scale pre-plasma primarily enhances the high-frequency component (
3 THz) of BTR.
Giant electromagnetic pulses (EMP) generated during the interaction of high-power lasers with solid targets can seriously degrade electrical measurements and equipment. EMP emission is caused by the acceleration of hot electrons inside the target, which produce radiation across a wide band from DC to terahertz frequencies. Improved understanding and control of EMP is vital as we enter a new era of high repetition rate, high intensity lasers (e.g. the Extreme Light Infrastructure). We present recent data from the VULCAN laser facility that demonstrates how EMP can be readily and effectively reduced. Characterization of the EMP was achieved using B-dot and D-dot probes that took measurements for a range of different target and laser parameters. We demonstrate that target stalk geometry, material composition, geodesic path length and foil surface area can all play a significant role in the reduction of EMP. A combination of electromagnetic wave and 3D particle-in-cell simulations is used to inform our conclusions about the effects of stalk geometry on EMP, providing an opportunity for comparison with existing charge separation models.
During early lactation, when requirements for energy and protein are high, tissue protein requirements cannot be fulfilled by microbial protein alone and the opportunity arises to feed protected protein as a supplement to provide UDP which will compensate for the deficit between tissue protein requirements and microbial protein supplied by RDP.
Housed pigs are exposed chronically to aerial pollutants, principally dust and ammonia, at concentrations that may affect performance, possibly by raising the incidence and prevalence of multi-factorial respiratory diseases. Tolerable limits for aerial pollutants are unknown. The aim of this experiment was to test the hypothesis that chronic exposure of weaner pigs to controlled concentrations of aerial dust and ammonia lead to slower growth and lower feed intake compared with controls kept in ‘fresh air’.
The SkyMapper Transient survey (SMT) is exploring variability in the southern sky by performing (a) a rolling search to discover and study supernovæ, and (b) a Target of Opportunity programme that uses the robotic SkyMapper Telescope at Siding Spring Observatory. The supernova survey is obtaining a non-targeted sample of Type Ia supernovæ (SNe Ia) at low redshifts, z < 0.1, and studying other interesting transients found with the search strategy. We have a Target of Opportunity programme with an automatic response mechanism to search for optical counterparts to gravitational-wave and fast radio-burst events; it benefits from SkyMapper’s large field of view of 5.7 sq. deg. and a rapid data reduction pipeline.
We present first results of the SMT survey. The SMT pipeline can process and obtain potential candidates within 12 hours of observation. It disentangles real transients from processing artefacts using a machine-learning algorithm. To date, SMT has discovered over 60 spectroscopically confirmed supernovæ, several peculiar objects, and over 40 SNe Ia including one (SNIa 2016hhd) which was found within the first few days of explosion. We have also participated in searches for optical counterparts of gravitational waves, fast radio bursts and other transients, and have published observations of the optical counterpart of the gravitational-wave event GW170817. We also participate in coordinated observations with the Deeper Wider Faster programme, and the Kepler K2 cosmology project.
In 2014 we conducted a survey for 6.7 GHz methanol masers with the Arecibo Telescope toward far infrared sources selected from the Hi-GAL catalog of massive cores. We found a number of sources with weak 6.7 GHz methanol masers, possibly indicating regions in early stages of star formation. Here we describe the results of follow-up observations that were conducted with the Very Large Array in New Mexico to characterize this new population of “weak” 6.7 GHz methanol masers.
VLA observations in the (J, K)=(3,3) line of ammonia reveal new structures in the Galactic center region. An approximate ring of emission is centered on the central ionized streamers. This ring, seen previously in millimeter-wave interferometer maps, is very clumpy in the ammonia emission, with size scales ≲10″ (0.4 pc). The clumps show good spatial and velocity agreement with the ionized gas, and are warm with brightness temperatures exceeding 30 K. A comparison of the (3,3) to (1,1) ratio indicates considerably higher gas temperatures. This circumnuclear ring may not be the dominant feature in the mass distribution of the circumnuclear gas. A streamer, immediately to the south of the Galactic center, connects the gas complex at lII= −4′ (~10 pc) directly to the Galactic center. This streamer may define the path for gas flow into the nuclear region.
We report VLA observations of H76α emission from the H II region in M–0.13–0.08, the Sgr A “15 km s−1 cloud.” The line to continuum flux ratio implies an electron temperature Te ~ 7500 K, slightly lower than measurements of Te in Sgr B2. The deduced number of early stars and the infrared luminosity are consistent with a normal IMF in this cloud.
Transcatheter pulmonary valve implantation is usually performed from a femoral venous – transfemoral – approach, but this may not be the optimal vascular access option in some patients. This study aimed to determine which group of patients might benefit from an internal jugular – transjugular – approach for transcatheter pulmonary valve implantation.
This multicentre retrospective study included all patients who underwent attempted transcatheter pulmonary valve placement in the right ventricular outflow tract between April 2010 and June 2012 at two large congenital heart centres. Patients were divided into two groups based on venous access site – transfemoral or transjugular. Patient characteristics, procedural outcomes, and complications were compared between groups.
Of 81 patients meeting the inclusion criteria (median age 16.4 years), the transjugular approach was used in 14 patients (17%). The transjugular group was younger (median age 11.9 versus 17.3 years), had lower body surface area (mean 1.33 versus 1.61 m2), more often had moderate or greater tricuspid regurgitation (29% versus 7%), and had a higher ratio of right ventricle-to-systemic systolic pressure (mean 82.4 versus 64.7). Patients requiring a transjugular approach after an unsuccessful transfemoral approach had longer fluoroscopic times and procedure duration.
The transjugular approach for transcatheter pulmonary valve implantation is used infrequently but is more often used in younger and smaller patients. Technical limitations from a transfemoral approach may be anticipated if there is moderate or greater tricuspid regurgitation or higher right ventricular pressures. In these patients, a transjugular approach should be considered early.
In traditional transit timing variations (TTVs) analysis of multi-planetary systems, the individual TTVs are first derived from transit fitting and later modelled using n-body dynamic simulations to constrain planetary masses. We show that fitting simultaneously the transit light curves with the system dynamics (photo-dynamical model) increases the precision of the TTV measurements and helps constrain the system architecture. We exemplify the advantages of applying this photo-dynamical model to a multi-planetary system found in K2 data very close to 3:2 mean motion resonance, K2-19. In this case the period of the larger TTV variations (libration period) is much longer (>1.5 years) than the duration of the K2 observations (80 days). However, our method allows to detect the short period TTVs produced by the orbital conjunctions between the planets that in turn permits to uniquely characterise the system. Therefore, our method can be used to constrain the masses of near-resonant systems even when the full libration curve is not observed.