4,031 research outputs found
VESS16. Impact of Renal Artery Angulation on Procedural Complexity During Fenestrated and Snorkel EVAR
K2-231 b: A sub-Neptune exoplanet transiting a solar twin in Ruprecht 147
We identify a sub-Neptune exoplanet ( R)
transiting a solar twin in the Ruprecht 147 star cluster (3 Gyr, 300 pc, [Fe/H]
= +0.1 dex). The ~81 day light curve for EPIC 219800881 (V = 12.71) from K2
Campaign 7 shows six transits with a period of 13.84 days, a depth of ~0.06%,
and a duration of ~4 hours. Based on our analysis of high-resolution MIKE
spectra, broadband optical and NIR photometry, the cluster parallax and
interstellar reddening, and isochrone models from PARSEC, Dartmouth, and MIST,
we estimate the following properties for the host star: M, R, and K. This star appears to be single, based on our modeling of the
photometry, the low radial velocity variability measured over nearly ten years,
and Keck/NIRC2 adaptive optics imaging and aperture-masking interferometry.
Applying a probabilistic mass-radius relation, we estimate that the mass of
this planet is M, which would cause a RV
semi-amplitude of m s that may be measurable with existing
precise RV facilities. After statistically validating this planet with BLENDER,
we now designate it K2-231 b, making it the second sub-stellar object to be
discovered in Ruprecht 147 and the first planet; it joins the small but growing
ranks of 23 other planets found in open clusters.Comment: 24 pages, 7 figures, light curve included as separate fil
Natural history of gutter-related type Ia endoleaks after snorkel/chimney endovascular aneurysm repair.
OBJECTIVE: Alternative endovascular strategies using parallel or snorkel/chimney (chimney endovascular aneurysm repair [ch-EVAR]) techniques have been developed to address the lack of widespread availability and manufacturing limitations with branched/fenestrated aortic devices for the treatment of complex abdominal aortic aneurysms. Despite high technical success and midterm patency of snorkel stent configurations, concerns remain regarding the perceived increased incidence of early gutter-related type Ia endoleaks. We aimed to evaluate the incidence and natural history of gutter-related type Ia endoleaks following ch-EVAR.
METHODS: Review of medical records and available imaging studies, including completion angiography and serial computed tomographic angiography, was performed for all patients undergoing ch-EVAR at our institution between September 2009 and January 2015. Only procedures involving ≥1 renal artery with or without visceral snorkel stents were included. Primary outcomes of the study were presence and persistence or resolution of early gutter-related type Ia endoleak. Secondary outcomes included aneurysm sac shrinkage and need for secondary intervention related to the presence of type Ia gutter endoleak.
RESULTS: Sixty patients (mean age, 75.8 ± 7.6 years; male, 70.0%) underwent ch-EVAR with a total of 111 snorkel stents (97 renal [33 bilateral renal], 12 superior mesenteric artery, 2 celiac). A mean of 1.9 ± 0.6 snorkel stents were placed per patient. Early gutter-related type Ia endoleaks were noted on 30.0% (n = 18) of initial postoperative imaging studies. Follow-up imaging revealed spontaneous resolution of these gutter endoleaks in 44.3%, 65.2%, and 88.4% of patients at 6, 12, and 18 months postprocedure, respectively. Long-term anticoagulation, degree of oversizing, stent type and diameter, and other clinical/anatomic variables were not significantly associated with presence of gutter endoleaks. Two patients (3.3%) required secondary intervention related to persistent gutter endoleak. At a mean radiologic follow-up of 20.9 months, no difference in mean aneurysm sac size change was observed between those with or without early type Ia gutter endoleak (-6.1 ± 10.0 mm vs -4.9 ± 11.5 mm; P = .23).
CONCLUSIONS: Gutter-related type Ia endoleaks represent a relatively frequent early occurrence after ch-EVAR, but appears to resolve spontaneously in the majority of cases during early to midterm follow-up. Given that few ch-EVAR patients require reintervention related to gutter endoleaks and the presence of such endoleak did not correlate to increased risk for aneurysm sac growth, its natural history may be more benign than originally expected
Time-resolved multi-mass ion imaging: femtosecond UV-VUV pump-probe spectroscopy with the PImMS camera
The Pixel-Imaging Mass Spectrometry (PImMS) camera allows for 3D charged
particle imaging measurements, in which the particle time-of-flight is recorded
along with position. Coupling the PImMS camera to an ultrafast
pump-probe velocity-map imaging spectroscopy apparatus therefore provides a
route to time-resolved multi-mass ion imaging, with both high count rates and
large dynamic range, thus allowing for rapid measurements of complex
photofragmentation dynamics. Furthermore, the use of vacuum ultraviolet
wavelengths for the probe pulse allows for an enhanced observation window for
the study of excited state molecular dynamics in small polyatomic molecules
having relatively high ionization potentials. Herein, preliminary time-resolved
multi-mass imaging results from CFI photolysis are presented. The
experiments utilized femtosecond UV and VUV (160.8~nm and 267~nm) pump and
probe laser pulses in order to demonstrate and explore this new time-resolved
experimental ion imaging configuration. The data indicates the depth and power
of this measurement modality, with a range of photofragments readily observed,
and many indications of complex underlying wavepacket dynamics on the excited
state(s) prepared
Carbon dioxide in the atmosphere: Isotopic exchange with ozone and its use as a tracer in the middle atmosphere
Atmospheric heavy ozone is enriched in the isotopes ^(18)O and ^(17)O. The magnitude of this enhancement, of the order of 100‰, is very large compared with that commonly known in atmospheric chemistry and geochemistry. The heavy oxygen atom in heavy ozone is therefore useful as a tracer of chemical species and pathways that involve ozone or its derived products. As a test of the isotopic exchange reactions, we successfully carry out a series of numerical experiments to simulate the results of the laboratory experiments performed by Wen and Thiemens [1993] on ozone and CO_2. A small discrepancy between the experimental and the model values for ^(17)O exchange is also revealed. The results are used to compute the magnitude of isotopic exchange between ozone and carbon dioxide via the excited atom O(^1D) in the middle atmosphere. The model for ^(18)O is in good agreement with the observed values
Photofragmentation dynamics of <i>N,N</i>-dimethylformamide following excitation at 193 nm
N,N-dimethylformamide, HCON(CH3)2, is a useful model compound for
investigating peptide bond photofragmentation dynamics. We report data
from a comprehensive experimental and theoretical study into the photofragmentation
dynamics of N,N-dimethylformamide in the gas phase at 193 nm.
Through a combination of velocity-map imaging and hydrogen atom Rydberg
tagging photofragment translational spectroscopy, we have identified
two primary fragmentation channels, namely fission of the NCO `peptide'
bond, and NCH3 bond fission leading to loss of CH3. The possible fragmentation
channels leading to the observed products are rationalised with
recourse to CASPT2 calculations of the ground and first few excited-state
potential energy curves along the relevant dissociation coordinates, and the
results are compared with data from previous experimental and theoretical studies on the same system
Brief of Intellectual Property Law Scholars As Amici Curiae in Support of Neither Party, WesternGeco LLC v. Ion Geophysical Corp., No. 16-1011, US Supreme Court
This amici curiae brief was filed on behalf of Intellectual Property Law Scholars in WesternGeco LLC v. Ion Geophysical Corp. in the U.S. Supreme Court. The question presented is:
Whether the U.S. Court of Appeals for the Federal Circuit erred in holding that lost profits arising from prohibited combinations occurring outside of the United States are categorically unavailable in cases in which patent infringement is proven under 35 U.S.C. § 271(f).
In RJR Nabisco, Inc. v. European Community, 136 S. Ct. 2090 (2016), the Supreme Court articulated a two-step method for assessing the extraterritorial reach of a US statute:
1. A court should determine whether the presumption against extraterritoriality has been rebutted—that is, whether the statute gives a clear, affirmative indication that it applies extraterritorially. If the presumption is rebutted, the statute may have extraterritorial reach.
2. But even if the presumption has not been rebutted, a court should look at the focus of the statute. If the conduct relevant to the statute\u27s focus occurred in the United States, then the case involves a permissible domestic application even if other conduct occurred abroad; but if the conduct relevant to the focus occurred in a foreign country, then the case involves an impermissible extraterritorial application regardless of any other conduct that occurred in U.S. territory.
The brief of amici curiae makes the follow points:
1. The Supreme Court has not squarely answered the question as to whether the presumption against extraterritoriality applies separately to remedial provisions of a statute generally (here whether it applies to § 284). We argue it does.
2. We argue that the territorial reach § 284 necessarily depends the relevant provision of § 271 used to find liability. Here, under § 271(f), the presumption is rebutted (though it would not be generally for a case under § 271(a), with NTP v. Research in Motion may be a counter-example when one looks at the focus at step 2)).
3. We also argue that the Court should offer more guidance as to what happens even if the RJR test is satisfied. RJR Nabisco seems to operate in binary fashion -- either the statute has extraterritorial reach or it doesn\u27t. But Microsoft Corp. v. AT&T Corp., and earlier Supreme Court decision also interpreting 35 U.S.C. § 271(f), suggests that the presumption may still have a role in interpreting a statute. We offer two suggestions on how the presumption should operate in this context. First, courts should seriously and formally consider issues of comity and potential conflicts with foreign law in assessing whether to apply U.S. law extraterritorially. Second, that territoriality should remain relevant in assessments of proximate cause
Validation of the myocardial-ischaemic-injury-index machine learning algorithm to guide the diagnosis of myocardial infarction in a heterogenous population: a prespecified exploratory analysis
BACKGROUND: Diagnostic pathways for myocardial infarction rely on fixed troponin thresholds, which do not recognise that troponin varies by age, sex, and time within individuals. To overcome this limitation, we recently introduced a machine learning algorithm that predicts the likelihood of myocardial infarction. Our aim was to evaluate whether this algorithm performs well in routine clinical practice and predicts subsequent events. METHODS: The myocardial-ischaemic-injury-index (MI3) algorithm was validated in a prespecified exploratory analysis using data from a multi-centre randomised trial done in Scotland, UK that included consecutive patients with suspected acute coronary syndrome undergoing serial high-sensitivity cardiac troponin I measurement. Patients with ST-segment elevation myocardial infarction were excluded. MI3 incorporates age, sex, and two troponin measurements to compute a value (0-100) reflecting an individual's likelihood of myocardial infarction during the index visit and estimates diagnostic performance metrics (including area under the receiver-operating-characteristic curve, and the sensitivity, specificity, negative predictive value, and positive predictive value) at the computed score. Model performance for an index diagnosis of myocardial infarction (type 1 or type 4b), and for subsequent myocardial infarction or cardiovascular death at 1 year was determined using the previously defined low-probability threshold (1·6) and high-probability MI3 threshold (49·7). The trial is registered with ClinicalTrials.gov, NCT01852123. FINDINGS: In total, 20 761 patients (64 years [SD 16], 9597 [46%] women) enrolled between June 10, 2013, and March 3, 2016, were included from the High-STEACS trial cohort, of whom 3272 (15·8%) had myocardial infarction. MI3 had an area under the receiver-operating-characteristic curve of 0·949 (95% CI 0·946-0·952) identifying 12 983 (62·5%) patients as low-probability for myocardial infarction at the pre-specified threshold (MI3 score <1·6; sensitivity 99·3% [95% CI 99·0-99·6], negative predictive value 99·8% [99·8-99·9]), and 2961 (14·3%) as high-probability at the pre-specified threshold (MI3 score ≥49·7; specificity 95·0% [94·6-95·3], positive predictive value 70·4% [68·7-72·0]). At 1 year, subsequent myocardial infarction or cardiovascular death occurred more often in high-probability patients than low-probability patients (520 [17·6%] of 2961 vs 197 [1·5%] of 12 983], p<0·0001). INTERPRETATION: In consecutive patients undergoing serial cardiac troponin measurement for suspected acute coronary syndrome, the MI3 algorithm accurately estimated the likelihood of myocardial infarction and predicted subsequent adverse cardiovascular events. By providing individual probabilities the MI3 algorithm could improve the diagnosis and assessment of risk in patients with suspected acute coronary syndrome. FUNDING: Medical Research Council, British Heart Foundation, National Institute for Health Research, and NHSX
Inflation on the Brane with Vanishing Gravity
Many existing models of brane inflation suffer from a steep irreducible
gravitational potential between the branes that causes inflation to end too
early. Inspired by the fact that point masses in 2+1 D exert no gravitational
force, we propose a novel unwarped and non-supersymmetric setup for inflation,
consisting of 3-branes in two extra dimensions compactified on a sphere. The
size of the sphere is stabilized by a combination of a bulk cosmological
constant and a magnetic flux. Computing the 4D effective potential between
probe branes in this background, we find a non-zero contribution only from
exchange of level-1 KK modes of the graviton and radion. Identifying antipodal
points on the 2-sphere projects out these modes, eliminating entirely the
troublesome gravitational contribution to the inflationary potential.Comment: 19 pages, 11 figures, JHEP forma
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