We have explored radial color and stellar surface mass density profiles for a sample of 85 late-type spiral galaxies with deep (down to image27 mag arcsec super(-2)) SDSS image - and image -band ...surface brightness profiles. About 90% of the light profiles have been classified as broken exponentials, exhibiting either truncations (Type II galaxies) or antitruncations (Type III galaxies). The color profiles of Type II galaxies show a 'image shape' with a minimum of image mag at the break radius. Around the break radius, Type III galaxies have a plateau region with a color of image. Using the color to calculate the stellar surface mass density profiles reveals a surprising result. The breaks, well established in the light profiles of the truncated galaxies, are almost gone, and the mass profiles now resemble those of the pure exponential (Type I) galaxies. This result suggests that the origin of the break in Type II galaxies is more likely due to a radial change in stellar population than being associated with an actual drop in the distribution of mass. Type III galaxies, however, seem to preserve their shape in the stellar mass density profiles. We find that the stellar surface mass density at the break for truncated galaxies is image pc super(-2) and for the antitruncated ones is image pc super(-2). We estimate that the fraction of stellar mass outside the break radius is image15% for truncated galaxies and image9% for antitruncated galaxies.
•The majority (75.3%) of patients with MTLE-HS remain refractory to 2 or more appropriate AED trials.•Newer AEDs are not more likely to control seizures in MTLE-HS than older AEDs.•Duration of ...epilepsy significantly correlates with number of AED trials in seizure free but not pharmacoresistant patients.
This study aims to evaluate the overall prognosis, prognostic factors, and efficacy of treatment in patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) who have access to third generation anti-epileptic drugs but not to epilepsy surgery. Eighty-five MTLE-HS patients were retrospectively placed into a seizure-free (seizure-free for >1year) or drug-resistant group, and the two groups were compared on the basis of age, sex, age at onset of seizures, duration of epilepsy, side of lesion, handedness, EEG findings, history of CNS infection, history of febrile convulsions, history of head trauma, history of cognitive impairment, family history of seizures, number of current anti-epileptic drugs (AEDs), total number of AED trials, and presence of individual AEDs. Only 24.7% of MTLE-HS patients had achieved seizure freedom for >1 year. Poor prognosis and drug-resistance were associated with younger age at onset of seizures (p=0.002), longer duration of epilepsy (p=0.018), greater number of current AEDs (p<0.001), and greater total number of AED trials (p<0.001). In addition, regimens with newer AEDs had no greater efficacy than regimens with older AEDs. Most medically managed MTLE-HS patients do not achieve seizure freedom despite multiple AED trials, and treatment with third generation AEDs should not preclude evaluation for epilepsy surgery.
BACKGROUND: Management of surgical emergencies in spaceflight will pose a challenge as the era of exploration class missions dawns, requiring increased crew autonomy at a time when training and ...supplies will be limited. Ultrasound-guided percutaneous intervention would allow
for the management of a variety of pathologies with largely shared equipment and training. This proof-of-concept work attempts to determine the feasibility of "just-in-time" remote teaching and guidance of a sample procedure of this type.METHODS: Subjects naïve
to ultrasound-guided intervention were instructed via a short video regarding the technique for placement of a percutaneous drain into a simulated abscess within a gel phantom. Subjects were then guided through the performance of the procedure via two-way audiovisual communication with an
experienced remote assistant. Technical success was determined by the successful aspiration or expression of fluid from the simulated abscess following drain placement. This was then performed by and compared with staff experienced with such procedures. Time to completion and number of needle
redirections required were also measured.RESULTS: All 29 subjects naïve to interventional work and the 4 experienced control subjects achieved technical success. There was a statistically significant difference in the time to completion between the two groups, with the experienced
subjects averaging 2 min to completion and the inexperienced 5.8 min. There was no statistically significant difference in the number of redirections.DISCUSSION: This proof-of-concept work demonstrates high rates of technical success of percutaneous ultrasound-guided intervention
in previously inexperienced personnel when provided with brief just-in-time training and live two-way audiovisual guidance.Lerner DJ, Pohlen MS, Apland RC, Parivash SN. Just-in-time training with remote guidance for ultrasound-guided percutaneous intervention. Aerosp Med Hum
Perform. 2022; 93(12):882-886.
Overview of lunar dust toxicity risk Pohlen, Michael; Carroll, Danielle; Prisk, G Kim ...
NPJ microgravity,
12/2022, Letnik:
8, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Lunar dust (LD), the component of lunar regolith with particle sizes less than 20 μm, covers the surface of the Moon. Due to its fineness, jagged edges, and electrostatic charge, LD adheres to and ...coats almost any surface it contacts. As a result, LD poses known risks to the proper functioning of electronic and mechanical equipment on the lunar surface. However, its mechanical irritancy and chemical reactivity may also pose serious health risks to humans by a number of mechanisms. While Apollo astronauts reported mild short-lived respiratory symptoms, the spectrum of health effects associated with high-dose acute exposure or chronic low-dose exposure are not yet well-understood. This paper explores known and potential human risks of exposure to LD which are thought to be important in planning upcoming lunar missions and planetary surface work.
INTRODUCTION: The advancement of human spaceflight has made urgent the need to develop medical imaging technology to ensure a high level of in-flight care. To date, only ultrasound has been used in ...spaceflight. Radiography has multiple advantages over ultrasound, including lower
operator dependence, more rapid acquisition, typically higher spatial resolution, and characterization of tissue with acoustic impedance precluding ultrasound. This proof-of-concept work demonstrates for the first time the feasibility of performing human radiographs in microgravity.METHODS:
Radiographs of a phantom and human subject's hand, knee, chest, cervical spine, and pelvis were obtained aboard a parabolic flight in microgravity and simulated lunar gravity with various subject and operator positions. Control radiographs were acquired with the same system on the ground.
These radiographs were performed with a Food and Drug Administration-approved ultra-portable, wireless, battery-powered, digital x-ray system.RESULTS: The radiographs of the phantom acquired in reduced gravity were qualitatively and quantitatively compared to the ground controls
and found to exhibit similar diagnostic adequacy. There was no statistically significant difference in contrast resolution or spatial resolution with a spatial resolution across all imaging environments up to the Nyquist frequency of 3.6 line-pairs/mm and an average contrast-to-noise
ratio of 2.44.DISCUSSION: As mass, power, and volume limitations lessen over the coming decades and the miniaturization of imaging equipment continues, in-flight implementation of nonsonographic modalities will become practical. Given the demonstrated ease of use and satisfactory
image quality, portable radiography is ready to be the new frontier of space medical imaging.Lerner D, Pohlen M, Wang A, Walter J, Cairnie M, Gifford S. X-ray imaging in the simulated microgravity environment of parabolic flight. Aerosp Med Hum Perform. 2023; 94(10):786-791.
The disks of spiral galaxies are commonly thought to be truncated: the radial surface brightness profile steepens sharply beyond a certain radius (3-5 inner disk scale lengths). Here we present the ...radial brightness profiles of a number of barred S0-Sb galaxies with the opposite behavior: their outer profiles are distinctly shallower in slope than the main disk profile. We term these "antitruncations"; they are found in at least 25% of a larger sample of barred S0-Sb galaxies. There are two distinct types of antitruncations. About one-third show a fairly gradual transition and outer isophotes that are progressively rounder than the main disk isophotes, suggestive of a disk embedded within a more spheroidal outer zone--either the outer extent of the bulge or a separate stellar halo. But the majority of the profiles have rather sharp surface brightness transitions to the shallower, outer exponential profile and, crucially, outer isophotes that are not significantly rounder than the main disk; in the Sab-Sb galaxies, the outer isophotes include visible spiral arms. This suggests that the outer light is still part of the disk. A subset of these profiles are in galaxies with asymmetric outer isophotes (lopsided or one-armed spirals), suggesting that interactions may be responsible for at least some of the disklike antitruncations.
We have conducted a systematic search for stellar disk truncations in disklike galaxies at intermediate redshift (z < 1.1) using the Hubble Ultra Deep Field data. We use the position of the ...truncation as a direct estimator of the size of the stellar disk. After accounting for the surface brightness evolution of the galaxies, our results suggest that the radial position of the truncations has increased with cosmic time by 61-3 kpc in the last 68 Gyr. This result indicates a small to moderate (625%) inside-out growth of the disk galaxies since z61.
PDF
