6,746 research outputs found
Feasibility of chest ultrasound up to 42Â m underwater
After recent advancements, ultrasound has extended its applications from bedside clinical practice to wilderness medicine. Performing ultrasound scans in extreme environments can allow direct visualization of unique pathophysiological adaptations but can be technically challenging. This paper summarizes how a portable ultrasound apparatus was marinized to let scientific divers and sonographers perform ultrasound scans of the lungs underwater up to − 42 m. A metallic case protected the ultrasound apparatus inside; a frontal transparent panel with a glove allowed visualization and operation of the ultrasound by the diving sonographer. The inner pressure was equalized with environmental pressure through a compressed air tank connected with circuits similar to those used in SCUBA diving. Finally, the ultrasound probe exited the metallic case through a sealed aperture. No technical issues were reported after the first testing step and the real experiments
The formation heritage of Jupiter Family Comet 10P/Tempel 2 as revealed by infrared spectroscopy
We present spectral and spatial information for major volatile species in
Comet 10P/Tempel 2, based on high-dispersion infrared spectra acquired on UT
2010 July 26 (heliocentric distance Rh = 1.44 AU) and September 18 (Rh = 1.62
AU), following the comet's perihelion passage on UT 2010 July 04. The total
production rate for water on July 26 was (1.90 +/- 0.12) x 10^28 molecules s-1,
and abundances of six trace gases (relative to water) were: CH3OH (1.58% +/-
0.23), C2H6 (0.39% +/- 0.04), NH3 (0.83% +/- 0.20), and HCN (0.13% +/- 0.02). A
detailed analysis of intensities for water emission lines provided a rotational
temperature of 35 +/- 3 K. The mean OPR is consistent with nuclear spin
populations in statistical equilibrium (OPR = 3.01 +/- 0.18), and the (1-sigma)
lower bound corresponds to a spin temperature > 38 K. Our measurements were
contemporaneous with a jet-like feature observed at optical wavelengths. The
spatial profiles of four primary volatiles display strong enhancements in the
jet direction, which favors release from a localized vent on the nucleus. The
measured IR continuum is much more sharply peaked and is consistent with a
dominant contribution from the nucleus itself. The peak intensities for H2O,
CH3OH, and C2H6 are offset by ~200 km in the jet direction, suggesting the
possible existence of a distributed source, such as the release of icy grains
that subsequently sublimed in the coma. On UT September 18, no obvious emission
lines were present in our spectra, nevertheless we obtained a 3-sigma upper
limit Q(H2O) < 2.86 x 10^27 molecules s-1
An easy synthesis for preparing bio-based hybrid adsorbent useful for fast adsorption of polar pollutants
For the first time, γ-Al2O3 and Bio-Based Substances (BBS) hybrids (A-BBS) were prepared through a simple electrostatic interaction occurring between alumina, used as a support, and BBS (Bio-Based Substance from composted biowastes) carrying positive and negative charges, respectively. We evaluated the optimal amount of BBS to be immobilized on the support and the stability of the resulting A-BBS in order to use this novel hybrid material as an adsorbent for the removal of polar pollutants. Characterization was carried out by X-Ray Diffraction (XRD) for evaluating the crystal structure of the support, Fourier transform infrared spectroscopy (FT-IR) to evidence the presence of BBS on the hybrid material, thermogravimetric analysis (TGA) to measure the thermal stability of the hybrid materials and quantify the BBS amount immobilized on the support, N2 adsorption at 77 K for the evaluation of the surface area and porosity of the systems, Zeta potential measurements to evaluate the effect of BBS immobilization on the surface charge of the particles and choose the substrates possibly interacting with them. Firstly, we tested the adsorption capability of three samples differently coated with BBS toward cationic species considering various adsorbate/adsorbent ratio. Crystal Violet (CV) was chosen as model pollutant to compare the performance of the hybrid materials with those of other materials described in the literature. The adsorption data were modeled by Langmuir and Freundlich adsorption isotherms. Then, we studied the adsorption capability of the developed material towards molecules with different structures; for this purpose, two contaminants of emerging concerns (carbamazepine and atenolol) were tested. The results indicate that A-BBS could be applied in wastewater treatment for the removal of a significant amount of polar species. In addition, a comparison with literature data concerning CV adsorption was carried out in order to evaluate the environmental impact of synthetic routes used to prepare different adsorbents
A Measurement of Water Vapour amid a Largely Quiescent Environment on Europa
Previous investigations proved the existence of local density enhancements in Europas atmosphere, advancing the idea of a possible origination from water plumes. These measurement strategies, however, were sensitive either to total absorption or atomic emissions, which limited the ability to assess the water content. Here we present direct searches for water vapour on Europa spanning dates from February 2016 to May 2017 with the Keck Observatory. Our global survey at infrared wavelengths resulted in non-detections on 16 out of 17 dates, with upper limits below the water abundances inferred from previous estimates. On one date (26 April 2016) we measured 2,095 658 tonnes of water vapour at Europas leading hemisphere. We suggest that the outgassing ls than previously estimated, with only rare localized events of stronger activity
Temporal and Spatial Aspects of Gas Release During the 2010 Apparition of Comet 103P/Hartley-2
We report measurements of eight primary volatiles (H2O, HCN, CH4, C2H6,
CH3OH, C2H2, H2CO, and NH3) and two product species (OH and NH2) in comet
103P/Hartley-2 using high dispersion infrared spectroscopy. We quantified the
long- and short-term behavior of volatile release over a three-month interval
that encompassed the comet's close approach to Earth, its perihelion passage,
and flyby of the comet by the Deep Impact spacecraft during the EPOXI mission.
We present production rates for individual species, their mixing ratios
relative to water, and their spatial distributions in the coma on multiple
dates. The production rates for water, ethane, HCN, and methanol vary in a
manner consistent with independent measures of nucleus rotation, but mixing
ratios for HCN, C2H6, & CH3OH are independent of rotational phase. Our results
demonstrate that the ensemble average composition of gas released from the
nucleus is well defined, and relatively constant over the three-month interval
(September 18 through December 17). If individual vents vary in composition,
enough diverse vents must be active simultaneously to approximate (in sum) the
bulk composition of the nucleus. The released primary volatiles exhibit diverse
spatial properties which favor the presence of separate polar and apolar ice
phases in the nucleus, establish dust and gas release from icy clumps (and
also, directly from the nucleus), and provide insights into the driver for the
cyanogen (CN) polar jet. The spatial distributions of C2H6 & HCN along the
near-polar jet (UT 19.5 October) and nearly orthogonal to it (UT 22.5 October)
are discussed relative to the origin of CN. The ortho-para ratio (OPR) of water
was 2.85 \pm 0.20; the lower bound (2.65) defines Tspin > 32 K. These values
are consistent with results returned from ISO in 1997.Comment: 18 pages, 3 figures, to be published in: Astrophysical Journal
Letter
The Composition of Comets
This paper is the result of the International Cometary Workshop, held in
Toulouse, France in April 2014, where the participants came together to assess
our knowledge of comets prior to the ESA Rosetta Mission. In this paper, we
look at the composition of the gas and dust from the comae of comets. With the
gas, we cover the various taxonomic studies that have broken comets into groups
and compare what is seen at all wavelengths. We also discuss what has been
learned from mass spectrometers during flybys. A few caveats for our
interpretation are discussed. With dust, much of our information comes from
flybys. They include {\it in situ} analyses as well as samples returned to
Earth for laboratory measurements. Remote sensing IR observations and
polarimetry are also discussed. For both gas and dust, we discuss what
instruments the Rosetta spacecraft and Philae lander will bring to bear to
improve our understanding of comet 67P/Churyumov-Gerasimenko as "ground-truth"
for our previous comprehensive studies. Finally, we summarize some of the
initial Rosetta Mission findings.Comment: To appear in Space Science Review
Long-term results in patients with T2-3 N0 distal rectal cancer undergoing radiotherapy before transanal endoscopic microsurgery
BACKGROUND: Local excision after radiotherapy for node-negative low rectal cancer may be an alternative to radical excision. This study evaluated the results of local excision in patients with small (less than 3 cm in diameter) T2 and T3 distal rectal tumours following neoadjuvant therapy. METHODS: One hundred patients with rectal cancer (54 uT2 and 46 uT3 uN0 tumours) were enrolled. All patients underwent preoperative radiotherapy followed by local excision by means of transanal endoscopic microsurgery. RESULTS: Definitive histological examination revealed nine pT1, 54 pT2 and 19 pT3 tumours. A complete response (R0) or microscopic residual tumour (R1mic) was found in three and 15 patients respectively. Minor complications occurred in 11 patients and major complications in two. At a median follow-up of 55 (range 7-120) months, the local failure rate was 5 per cent and metastatic disease was found in two patients. The cancer-specific survival rate at 90 months' follow-up was 89 per cent, and the overall survival rate 72 per cent. Salvage abdominoperineal resection was performed in three patients, two of whom were disease free at 15 and 19 months. CONCLUSION: Treatment of small uT2 and uT3 uN0 rectal cancers with preoperative high-dose radiotherapy followed by transanal endoscopic microsurgery is an acceptable alternative to conventional radical resection
- …