18 research outputs found
High frequency magnetic oscillations of the organic metal -(ET)ZnBr(CHCl) in pulsed magnetic field of up to 81 T
De Haas-van Alphen oscillations of the organic metal
-(ET)ZnBr(CHCl) are studied in pulsed magnetic
fields up to 81 T. The long decay time of the pulse allows determining reliable
field-dependent amplitudes of Fourier components with frequencies up to several
kiloteslas. The Fourier spectrum is in agreement with the model of a linear
chain of coupled orbits. In this model, all the observed frequencies are linear
combinations of the frequency linked to the basic orbit and to the
magnetic-breakdown orbit .Comment: 6 pages, 4 figure
An Unusual Case of Tracheoesophageal Fistulae
Acquired tracheoesophageal fistulae (TEF) are commonly due to malignancy (M. F. Reed and D. J. Mathisen, 2003). We present the case of a patient with a deceptive history for TEF and report an approach that provides adequate oxygenation, ventilation, surgical exposure, and postoperative analgesia with excellent outcome
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Postoperative pulmonary complications with adjuvant regional anesthesia versus general anesthesia alone: a sub-analysis of the Perioperative Research Network study
Background
Adjuvant regional anesthesia is often selected for patients or procedures with high risk of pulmonary complications after general anesthesia. The benefit of adjuvant regional anesthesia to reduce postoperative pulmonary complications remains uncertain. In a prospective observational multicenter study, patients scheduled for non-cardiothoracic surgery with at least one postoperative pulmonary complication surprisingly received adjuvant regional anesthesia more frequently than those with no complications. We hypothesized that, after adjusting for surgical and patient complexity variables, the incidence of postoperative pulmonary complications would not be associated with adjuvant regional anesthesia.
Methods
We performed a secondary analysis of a prospective observational multicenter study including 1202 American Society of Anesthesiologists physical status 3 patients undergoing non-cardiothoracic surgery. Patients were classified as receiving either adjuvant regional anesthesia or general anesthesia alone. Predefined pulmonary complications within the first seven postoperative days were prospectively identified. Groups were compared using bivariable and multivariable hierarchical logistic regression analyses for the outcome of at least one postoperative pulmonary complication.
Results
Adjuvant regional anesthesia was performed in 266 (22.1%) patients and not performed in 936 (77.9%). The incidence of postoperative pulmonary complications was greater in patients receiving adjuvant regional anesthesia (42.1%) than in patients without it (30.9%) (site adjusted p = 0.007), but this association was not confirmed after adjusting for covariates (adjusted OR 1.37; 95% CI, 0.83–2.25; p = 0.165).
Conclusion
After adjusting for surgical and patient complexity, adjuvant regional anesthesia versus general anesthesia alone was not associated with a greater incidence of postoperative pulmonary complications in this multicenter cohort of non-cardiothoracic surgery patients
Decimetre-scaled spectrophotometric properties of the nucleus of comet 67P/Churyumov-Gerasimenko from OSIRIS observations
We present the results of the photometric and spectrophotometric properties of the 67P/Churyumov-Gerasimenko nucleus derived with the Optical, Spectroscopic and Infrared Remote Imaging System instrument during the closest fly-by over the comet, which took place on 2015 February 14 at a distance of ~6 km from the surface. Several images covering the 0°-33° phase angle range were acquired, and the spatial resolution achieved was 11 cm pixel-1. The flown-by region is located on the big lobe of the comet, near the borders of the Ash, Apis and Imhotep regions. Our analysis shows that this region features local heterogeneities at the decimetre scale. We observed difference of reflectance up to 40 per cent between bright spots and sombre regions, and spectral slope variations up to 50 per cent. The spectral reddening effect observed globally on the comet surface by Fornasier et al. (2015) is also observed locally on this region, but with a less steep behaviour. We note that numerous metre-sized boulders, which exhibit a smaller opposition effect, also appear spectrally redder than their surroundings. In this region, we found no evidence linking observed bright spots to exposed water-ice-rich material.We fitted our data set using the Hapke 2008 photometric model. The region overflown is globally as dark as the whole nucleus (geometric albedo of 6.8 per cent) and it has a high porosity value in the uppermost layers (86 per cent). These results of the photometric analysis at a decimetre scale indicate that the photometric properties of the flown-by region are similar to those previously found for the whole nucleus
Predicting Important Residues and Interaction Pathways in Proteins Using Gaussian Network Model: Binding and Stability of HLA Proteins
A statistical thermodynamics approach is proposed to determine structurally and functionally important residues in native proteins that are involved in energy exchange with a ligand and other residues along an interaction pathway. The structure-function relationships, ligand binding and allosteric activities of ten structures of HLA Class I proteins of the immune system are studied by the Gaussian Network Model. Five of these models are associated with inflammatory rheumatic disease and the remaining five are properly functioning. In the Gaussian Network Model, the protein structures are modeled as an elastic network where the inter-residue interactions are harmonic. Important residues and the interaction pathways in the proteins are identified by focusing on the largest eigenvalue of the residue interaction matrix. Predicted important residues match those known from previous experimental and clinical work. Graph perturbation is used to determine the response of the important residues along the interaction pathway. Differences in response patterns of the two sets of proteins are identified and their relations to disease are discussed
Diabetes mellitus in anaesthesia
Anaesthesiologists frequently encounter patients with diseases of the endocrine system, in particular diabetes mellitus. The major risk factors for people with diabetes undergoing surgery are the associated end-organ diseases: cardiovascular autonomic neuropathy, joint collagen tissue, and immune deficiency. Due to the fact that endocrine diseases can be associated with significant peri-operative morbidity and mortality, it is critical that anaesthesiologists understand these disorders and when indicated request the appropriate investigations. </jats:p
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Compact neutron generator development at LBNL
A wide variety of applications ranging from medical (BNCT, Boron Neutron Capture Therapy) and basic science (neutron imaging, material studies) to homeland security (explosive detection and nuclear material non-proliferation) are in need of compact, high flux neutron generators. The Plasma and Ion Source Technology Group in the Lawrence Berkeley National Laboratory is developing various neutron generators for these applications. These neutron generators employed either the D-D or the D-T fusion reaction for the neutron production. The deuterium or deuterium-tritium gas mixture is ionized in an RF-driven plasma source. The ions are then accelerated to {approx}100 keV energy using high current, high voltage DC-power supply to a target where the 2.45 MeV (for D-D reaction) or 14 MeV (for the D-T reaction) neutrons are generated. The development of two different types of neutron tubes are being discussed in this presentation, namely compact, pulsed operation neutron generators and cw, high yield neutron generators. These generators are currently operating at D-D neutron yields of 108 n/s and 109 n/s respectively. A facility, incorporating the larger neutron generator, has been constructed for Prompt Gamma Activation Analysis (PGAA) and Neutron Activation Analysis (NAA) measurements
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Compact neutron generator development at LBNL
A wide variety of applications ranging from medical (BNCT, Boron Neutron Capture Therapy) and basic science (neutron imaging, material studies) to homeland security (explosive detection and nuclear material non-proliferation) are in need of compact, high flux neutron generators. The Plasma and Ion Source Technology Group in the Lawrence Berkeley National Laboratory is developing various neutron generators for these applications. These neutron generators employed either the D-D or the D-T fusion reaction for the neutron production. The deuterium or deuterium-tritium gas mixture is ionized in an RF-driven plasma source. The ions are then accelerated to ~;100 keV energy using high current, high voltage DC-power supply to a target where the 2.45 MeV (for D-D reaction) or 14 MeV (for the D-T reaction) neutrons are generated. The development of two different types of neutron tubes are being discussed in this presentation, namely compact, pulsed operation neutron generators and cw, high yield neutron generators. These generators are currently operating at D-D neutron yields of 108 n/s and 109 n/s respectively. A facility, incorporating the larger neutron generator, has been constructed for Prompt Gamma Activation Analysis (PGAA) and Neutron Activation Analysis (NAA) measurements
Factors which predict safe extubation in the operating room following cardiac surgery
Extubation in the operating room (OR) after cardiac surgery is hampered by safety concerns, psychological reluctance, and uncertain economic benefit. We have studied the factors affecting the feasibility of extubation in the OR after cardiac surgery and its safety.
The outcomes of 78 patients extubated in the OR after open heart surgery were retrospectively compared to a matched control group of 80 patients with similar demographics, co-morbidities, and operative procedures, that were performed over the same time period, but extubated in the intensive care unit (ICU) following a standard weaning protocol. Variables collected included the incidence of subsequent unplanned tracheal reintubation in the ICU, postoperative complications, need for mediastinal re-exploration, surgical and OR times, and ICU and hospital lengths of stay.
Out of a total of 372 cardiac procedures performed during the designated time frame, 78 (21%) resulted in extubation in the OR, mostly after off-pump coronary revascularization (41%) and aortic valve replacement (19.4%). Preoperative hypertension, EF ≥30%, off-bypass revascularization and shorter surgical times increased the likelihood of extubation in the OR. Extubation in the OR did not increase perioperative morbidity and mortality rates, but decreased the length of ICU and hospital stays. The incidence of unanticipated subsequent tracheal intubation in the ICU was comparable to noncardiac high-risk procedures (2.5%).
Extubation in the OR can be safely performed in a select group of cardiac surgery patients without any increase in postoperative morbidity or mortality. The proposed mathematical model performed reasonably well in predicting a successful extubation in the OR