ABSTRACT
Summary: The objective of our study was to evaluate the association between the previously described asthma risk factors and the prevalence of asthma in a population of Brazilian adults. A population-based cross-sectional study was conducted using data collected from 7891 patients. All patients in the database > 18 years of age were included. The following variables were collected from the health plan database: age, body mass index, smoking status, alcohol consumption, sedentary lifestyle, heart disease, hypertension, diabetes, and asthma diagnosis. The frequency of the collected variables was compared between patients with or without an asthma diagnosis, and logistic regression was performed. Of our total sample (7891 patients), 150 (1.9%) had asthma. The mean age of patients with asthma was 39.4 years. 1.4% of normal weight patients had the diagnosis of asthma, while 2.4% of overweight and 2.2% of obese patients had the diagnosis. Multivariate analysis demonstrated that a sedentary lifestyle and overweight and obesity were independently associated with asthma prevalence Odds Ratio (OR) (95% confidence interval): (1.61 (1.16-2.22) and 1.25 (1.03-1.52) respectively). Our data provide evidence that some clinical characteristics, such as sedentarism, overweight, and obesity, may be related to the prevalence of asthma in an adult population in southeastern Brazil. Such factors could be modified and better understood through multidisciplinary research and health programs that evaluate the risk factors for asthma in large populations.
ABSTRACT
Diagnostic use of single-pulse x-ray diffraction (XRD) at pulsed power facilities can be challenging due to factors such as the high flux and brightness requirements for diffraction and the geometric constraints of experimental platforms. By necessity, the x-ray source is usually positioned very close, within a few inches of the sample. On dynamic compression platforms, this puts the x-ray source in the debris field. We coupled x-ray polycapillary optics to a single-shot needle-and-washer x-ray diode source using a laser-based alignment scheme to obtain high-quality x-ray diffraction using a single 16 ns x-ray pulse with the source >1 m from the sample. The system was tested on a Mo sample in reflection geometry using 17 keV x-rays from a Mo anode. We also identified an anode conditioning effect that increased the x-ray intensity by 180%. Quantitative measurements of the x-ray focal spot produced by the polycapillary yielded a total x-ray flux on the sample of 3.3 ± 0.5 × 10(7) molybdenum Kα photons.
ABSTRACT
Hohlraums are employed at the national ignition facility to convert laser energy into a thermal x-radiation drive, which implodes a fusion capsule, thus compressing the fuel. The x-radiation drive is measured with a low spectral resolution, time-resolved x-ray spectrometer, which views the region around the hohlraum's laser entrance hole. This measurement has no spatial resolution. To convert this to the drive inside the hohlraum, the size of the hohlraum's opening ("clear aperture") and fraction of the measured x-radiation, which comes from this opening, must be known. The size of the clear aperture is measured with the time integrated static x-ray imager (SXI). A soft x-ray imaging channel has been added to the SXI to measure the fraction of x-radiation emitted from inside the clear aperture. A multilayer mirror plus filter selects an x-ray band centered at 870 eV, near the peak of the x-ray spectrum of a 300 eV blackbody. Results from this channel and corrections to the x-radiation drive are discussed.
ABSTRACT
A temporally gated x-ray framing camera based on a proximity focus microchannel plate is one of the most important diagnostic tools of inertial confinement fusion experiments. However, fusion neutrons produced in imploded capsules interact with structures surrounding the camera and produce background to x-ray signals. To understand the mechanisms of this neutron induced background, we tested several gated x-ray cameras in the presence of 14 MeV neutrons produced at the Omega laser facility. Differences between background levels observed with photographic film readout and charge-coupled-device readout have been studied.
ABSTRACT
The static x-ray imager at the National Ignition Facility is a pinhole camera using a CCD detector to obtain images of Hohlraum wall x-ray drive illumination patterns seen through the laser entrance hole (LEH). Carefully chosen filters, combined with the CCD response, allow recording images in the x-ray range of 3-5 keV with 60 µm spatial resolution. The routines used to obtain the apparent size of the backlit LEH and the location and intensity of beam spots are discussed and compared to predictions. A new soft x-ray channel centered at 870 eV (near the x-ray peak of a 300 eV temperature ignition Hohlraum) is discussed.
ABSTRACT
The National Ignition Facility will soon be producing x-ray flux and neutron yields higher than any produced in laser driven implosion experiments in the past. Even a non-igniting capsule will require x-ray imaging of near burning plasmas at 10(17) neutrons, requiring x-ray recording systems to work in more hostile conditions than we have encountered in past laser facilities. We will present modeling, experimental data and design concepts for x-ray imaging with electronic recording systems for this environment (ARIANE). A novel instrument, active readout in a nuclear environment, is described which uses the time-of-flight difference between the gated x-ray signal and the neutron which induces a background signal to increase the yield at which gated cameras can be used.
ABSTRACT
Fulminant hepatic failure (FHF), although not frequent, produces a high mortality rate of 70% to 90%. This study describes the management of FHF patients without the use of any intracranial pressure monitoring device.
