3,225 research outputs found
History of the Innovation of Damage Control for Management of Trauma Patients: 1902-2016
Objective: To review the history of the innovation of damage control (DC) for management of trauma patients. Background: DC is an important development in trauma care that provides a valuable case study in surgical innovation. Methods: We searched bibliographic databases (1950-2015), conference abstracts (2009-2013), Web sites, textbooks, and bibliographies for articles relating to trauma DC. The innovation of DC was then classified according to the Innovation, Development, Exploration, Assessment, and Long-term study model of surgical innovation. Results: The innovation\u27\u27 of DC originated from the use of therapeutic liver packing, a practice that had previously been abandoned after World War II because of adverse events. It then developed\u27\u27 into abbreviated laparotomy using rapid conservative operative techniques.\u27\u27 Subsequent exploration\u27\u27 resulted in the application of DC to increasingly complex abdominal injuries and thoracic, peripheral vascular, and orthopedic injuries. Increasing use of DC laparotomy was followed by growing reports of postinjury abdominal compartment syndrome and prophylactic use of the open abdomen to prevent intra-abdominal hypertension after DC laparotomy. By the year 2000, DC surgery had been widely adopted and was recommended for use in surgical journals, textbooks, and teaching courses ( assessment\u27\u27 stage of innovation). Long-term study\u27\u27 of DC is raising questions about whether the procedure should be used more selectively in the context of improving resuscitation practices. Conclusions: The history of the innovation of DC illustrates how a previously abandoned surgical technique was adapted and readopted in response to an increased understanding of trauma patient physiology and changing injury patterns and trauma resuscitation practices
Saccadic modulation of neural excitability in auditory areas of the neocortex
In natural "active" vision, humans and other primates use eye movements (saccades) to sample bits of information from visual scenes. In the visual cortex, non-retinal signals linked to saccades shift visual cortical neurons into a high excitability state as each saccade ends. The extent of this saccadic modulation outside of the visual system is unknown. Here, we show that during natural viewing, saccades modulate excitability in numerous auditory cortical areas with a temporal pattern complementary to that seen in visual areas. Control somatosensory cortical recordings indicate that the temporal pattern is unique to auditory areas. Bidirectional functional connectivity patterns suggest that these effects may arise from regions involved in saccade generation. We propose that by using saccadic signals to yoke excitability states in auditory areas to those in visual areas, the brain can improve information processing in complex natural settings
Field effect enhancement in buffered quantum nanowire networks
III-V semiconductor nanowires have shown great potential in various quantum
transport experiments. However, realizing a scalable high-quality
nanowire-based platform that could lead to quantum information applications has
been challenging. Here, we study the potential of selective area growth by
molecular beam epitaxy of InAs nanowire networks grown on GaAs-based buffer
layers. The buffered geometry allows for substantial elastic strain relaxation
and a strong enhancement of field effect mobility. We show that the networks
possess strong spin-orbit interaction and long phase coherence lengths with a
temperature dependence indicating ballistic transport. With these findings, and
the compatibility of the growth method with hybrid epitaxy, we conclude that
the material platform fulfills the requirements for a wide range of quantum
experiments and applications
Land Use and Land Cover Affect the Depth Distribution of Soil Carbon: Insights From a Large Database of Soil Profiles
Soils contain a large and dynamic fraction of global terrestrial carbon stocks. The distribution of soil carbon (SC) with depth varies among ecosystems and land uses and is an important factor in calculating SC stocks and their vulnerabilities. Systematic analysis of SC depth distributions across databases of SC profiles has been challenging due to the heterogeneity of soil profile measurements, which vary in depth sampling. Here, we fit over 40,000 SC depth profiles to an exponential decline relationship with depth to determine SC concentration at the top of the mineral soil, minimum SC concentration at depth, and the characteristic “length” of SC concentration decline with depth. Fitting these parameters allowed profile characteristics to be analyzed across a large and heterogeneous dataset. We then assessed the differences in these depth parameters across soil orders and land cover types and between soil profiles with or without a history of tillage, as represented by the presence of an Ap horizon. We found that historically tilled soils had more gradual decreases of SC with depth (greater e-folding depth or Z∗), deeper SC profiles, lower SC concentrations at the top of the mineral soil, and lower total SC stocks integrated to 30 cm. The large database of profiles allowed these results to be confirmed across different land cover types and spatial areas within the Continental United States, providing robust evidence for systematic impacts of historical tillage on SC stocks and depth distributions
Left ventricular mass and geometric distribution in treated and untreated hypertension: Impact by gender
The Spitzer c2d Survey of Weak-line T Tauri Stars II: New Constraints on the Timescale for Planet Building
One of the central goals of the Spitzer Legacy Project ``From Molecular Cores
to Planet-forming Disks'' (c2d) is to determine the frequency of remnant
circumstellar disks around weak-line T Tauri stars (wTTs) and to study the
properties and evolutionary status of these disks. Here we present a census of
disks for a sample of over 230 spectroscopically identified wTTs located in the
c2d IRAC (3.6, 4.5, 4.8, and 8.0 um) and MIPS (24 um) maps of the Ophiuchus,
Lupus, and Perseus Molecular Clouds. We find that ~20% of the wTTs in a
magnitude limited subsample have noticeable IR-excesses at IRAC wavelengths
indicating the presence of a circumstellar disk. The disk frequencies we find
in these 3 regions are ~3-6 times larger than that recently found for a sample
of 83 relatively isolated wTTs located, for the most part, outside the highest
extinction regions covered by the c2d IRAC and MIPS maps. The disk fractions we
find are more consistent with those obtained in recent Spitzer studies of wTTs
in young clusters such as IC 348 and Tr 37. From their location in the H-R
diagram, we find that, in our sample, the wTTs with excesses are among the
younger part of the age distribution. Still, up to ~50% of the apparently
youngest stars in the sample show no evidence of IR excess, suggesting that the
circumstellar disks of a sizable fraction of pre-main-sequence stars dissipate
in a timescale of ~1 Myr. We also find that none of the stars in our sample
apparently older than ~10 Myrs have detectable circumstellar disks at
wavelengths < 24 um. Also, we find that the wTTs disks in our sample exhibit a
wide range of properties (SED morphology, inner radius, L_DISK/L*, etc) which
bridge the gaps observed between the cTTs and the debris disk regimes.Comment: 54 pages, 13 figures, Accepted by Ap
A 15.65 solar mass black hole in an eclipsing binary in the nearby spiral galaxy Messier 33
Stellar-mass black holes are discovered in X-ray emitting binary systems,
where their mass can be determined from the dynamics of their companion stars.
Models of stellar evolution have difficulty producing black holes in close
binaries with masses >10 solar masses, which is consistent with the fact that
the most massive stellar black holes known so all have masses within 1 sigma of
10 solar masses. Here we report a mass of 15.65 +/- 1.45 solar masses for the
black hole in the recently discovered system M33 X-7, which is located in the
nearby galaxy Messier 33 (M33) and is the only known black hole that is in an
eclipsing binary. In order to produce such a massive black hole, the progenitor
star must have retained much of its outer envelope until after helium fusion in
the core was completed. On the other hand, in order for the black hole to be in
its present 3.45 day orbit about its 70.0 +/- 6.9 solar mass companion, there
must have been a ``common envelope'' phase of evolution in which a significant
amount of mass was lost from the system. We find the common envelope phase
could not have occured in M33 X-7 unless the amount of mass lost from the
progenitor during its evolution was an order of magnitude less than what is
usually assumed in evolutionary models of massive stars.Comment: To appear in Nature October 18, 2007. Four figures (one color figure
degraded). Differs slightly from published version. Supplementary Information
follows in a separate postin
Incident Gallstones During Somatostatin Analog Treatment are Associated with Acute Biliary Complications Especially After Discontinuation
INTRODUCTION: Gallstones are a known adverse effect of somatostatin analogs, but the exact incidence and clinical implications are unknown. OBJECTIVES: The aim of this study was to investigate the incidence of gallstones on imaging and related complications in unbiased trial data. METHODS: Data from the DIPAK 1 trial, in which 305 polycystic kidney disease patients were randomized to standard of care (SoC) or lanreotide for 120 weeks, were used. Magnetic resonance imaging (MRI) was performed at baseline and end of treatment and was assessed for the presence, number, and size of gallstones. For all patients who had gallstones at the end of the trial, we obtained follow-up after the trial. RESULTS: Of 249 patients with data available, 11 patients randomized to lanreotide and four randomized to SoC had gallstones at baseline. During the study, new gallstones were formed in 19/124 patients using lanreotide (15%) and 1/125 patients receiving SoC (1%). The odds ratio for gallstone formation with lanreotide use was 25.9 (95% confidence interval 3.37–198.8; p 20 stones in 69% of patients) and small (≤ 3 mm in 63% of patients). Of the 19 patients with incident gallstones during lanreotide treatment, 9 experienced gallstone-associated complications, 8 of whom experienced gallstone-associated complications after discontinuation of treatment (median time after discontinuation 2.5 years). In patients with gallstones at baseline and in patients receiving SoC, no complications occurred. CONCLUSIONS: Treatment with a somatostatin analog leads to the formation of multiple, small gallstones that are associated with severe complications, especially after discontinuation of therapy. CLINICAL TRIAL REGISTRY WEBSITE AND TRIAL NUMBER: ClinicalTrials.gov (https://clinicaltrials.gov); NCT01616927. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40268-021-00342-7
Effect of losartan on performance and physiological responses to exercise at high altitude (5035 m)
Objective: Altitude-related and exercise-related elevations in blood pressure (BP) increase the likelihood of developing pulmonary hypertension and high-altitude illness during high-altitude sojourn. This study examined the antihypertensive effect and potential exercise benefit of the angiotensin II receptor antagonist losartan when taken at altitude. Methods: Twenty participants, paired for age and ACE genotype status, completed a double-blinded, randomised study, where participants took either losartan (100 mg/day) or placebo for 21 days prior to arrival at 5035 m (Whymper Hut, Mt Chimborazo, Ecuador). Participants completed a maximal exercise test on a supine cycle ergometer at sea level (4 weeks prior) and within 48 hours of arrival to 5035 m (10-day ascent). Power output, beat-to-beat BP, oxygen saturation (SpO2) and heart rate (HR) were recorded during exercise, with resting BP collected from daily medicals during ascent. Before and immediately following exercise at 5035 m, extravascular lung water prevalence was assessed with ultrasound (quantified via B-line count). Results: At altitude, peak power was reduced relative to sea level (p<0.01) in both groups (losartan vs placebo: down 100±29 vs 91±28 W, p=0.55), while SpO2 (70±6 vs 70±5%, p=0.96) and HR (146±21 vs 149±24 bpm, p=0.78) were similar between groups at peak power, as was the increase in systolic BP from rest to peak power (up 80±37 vs 69±33 mm Hg, p=0.56). Exercise increased B-line count (p<0.05), but not differently between groups (up 5±5 vs 8±10, p=0.44). Conclusion: Losartan had no observable effect on resting or exercising BP, exercise-induced symptomology of pulmonary hypertension or performance at 5035 m
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