675 research outputs found

    Oliguria without serum creatinine increase after living donor liver transplantation is associated with adverse post-operative outcomes

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    Background: Acute kidney injury (AKI) is a common complication after liver transplantation and is associated with significant morbidity and mortality. Although clinical guidelines recommend defining AKI based on serum creatinine increase and oliguria, the validity and utility of the oliguric component of AKI definition remains largely unexplored. This study examined the incidence and the impact on clinical outcomes of oliguria meeting the urine output criterion of AKI in patients undergoing liver transplantation. The authors hypothesised that oliguria was an independent risk factor for adverse post-operative outcomes. Methods: This study retrospectively examined 320 patients who underwent living donor liver transplantation at our centre. AKI stages were allocated according to recent guidelines based on serum creatinine or urine output within 7 days of surgery. Results: The incidence of oliguria meeting the urine output criterion of AKI was 50.3%. Compared with creatinine criterion alone, incorporating oliguria into the diagnostic criteria dramatically increased the measured incidence of AKI from 39.7% to 62.2%. Compared with patients diagnosed without AKI using either criterion, oliguric patients without serum creatinine increase had significantly longer intensive care unit stays (median: 5 vs. 4 days, P = 0.016), longer hospital stays (median: 60 vs. 49 days, P = 0.014) and lower chronic kidney disease-free survival rate on post-operative day 90 (54.2% vs. 73.3%, P = 0.008). Conclusion: Oliguria is common after liver transplantation, and incorporating oliguria into the diagnostic criteria dramatically increases the measured incidence of AKI. Oliguria without serum creatinine increase was significantly associated with adverse post-operative outcomes

    Large Magnetic Susceptibility Anisotropy of Metallic Carbon Nanotubes

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    Through magnetic linear dichroism spectroscopy, the magnetic susceptibility anisotropy of metallic single-walled carbon nanotubes has been extracted and found to be 2-4 times greater than values for semiconducting single-walled carbon nanotubes. This large anisotropy is consistent with our calculations and can be understood in terms of large orbital paramagnetism of electrons in metallic nanotubes arising from the Aharonov-Bohm-phase-induced gap opening in a parallel field. We also compare our values with previous work for semiconducting nanotubes, which confirm a break from the prediction that the magnetic susceptibility anisotropy increases linearly with the diameter.Comment: 4 pages, 4 figure

    Electron cyclotron mass in undoped CdTe/CdMnTe quantum wells

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    Optically detected cyclotron resonance of two-dimensional electrons has been studied in nominally undoped CdTe/(Cd,Mn)Te quantum wells. The enhancement of carrier quantum confinement results in an increase of the electron cyclotron mass from 0.099m0m_0 to 0.112m0m_0 with well width decreasing from 30 down to 3.6 nm. Model calculations of the electron effective mass have been performed for this material system and good agreement with experimental data is achieved for an electron-phonon coupling constant α\alpha =0.32

    Thermal stability of amorphous sugar matrix, dried from methanol, as an amorphous solid dispersion carrier

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    [EN] Developing a technique to disperse hydrophobic ingredients homogeneously in a water-soluble solid matrix (solid dispersion) is one of the topics that have been extensively investigated in the pharmaceutical and food industries. Recently, we have devised a novel solid dispersion technique (surfactant-free solid dispersion), in which a preliminarily amorphized sugar was dissolved in an organic media containing hydrophobic component, without using any surface active substances, and then vacuum dried into the amorphous solid mixture [Food Chem., 197 (2016) 1136; Mol. Pharm., 14 (2017) 791]. In this study, the physicochemical properties, especially thermal stability of the surfactant-free amorphous solid dispersion, were investigated.Imamura, K.; Takeda, K.; Yamamoto, K.; Imanaka, H.; Ishida, N. (2018). Thermal stability of amorphous sugar matrix, dried from methanol, as an amorphous solid dispersion carrier. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 997-1004. https://doi.org/10.4995/IDS2018.2018.7716OCS997100

    DNA Nucleobase Synthesis at Titan Atmosphere Analog by Soft X-rays

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    Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of N2 and CH4 and includes traces of many simple organic compounds. This atmosphere also partly consists of haze and aerosol particles which during the last 4.5 gigayears have been processed by electric discharges, ions, and ionizing photons, being slowly deposited over the Titan surface. In this work, we investigate the possible effects produced by soft X-rays (and secondary electrons) on Titan aerosol analogs in an attempt to simulate some prebiotic photochemistry. The experiments have been performed inside a high vacuum chamber coupled to the soft X-ray spectroscopy beamline at the Brazilian Synchrotron Light Source, Campinas, Brazil. In-situ sample analyses were performed by a Fourier transform infrared spectrometer. The infrared spectra have presented several organic molecules, including nitriles and aromatic CN compounds. After the irradiation, the brownish-orange organic residue (tholin) was analyzed ex-situ by gas chromatographic (GC/MS) and nuclear magnetic resonance (1H NMR) techniques, revealing the presence of adenine (C5H5N5), one of the constituents of the DNA molecule. This confirms previous results which showed that the organic chemistry on the Titan surface can be very complex and extremely rich in prebiotic compounds. Molecules like these on the early Earth have found a place to allow life (as we know) to flourish.Comment: To appear in Journal of Physical Chemistry A.; Number of pages: 6; Number of Figures: 5; Number of Tables: 1; Number of references:49; Full paper at http://pubs.acs.org/doi/abs/10.1021/jp902824

    Carotid shunt provides cerebral protection during emergency coronary artery bypass grafting in a patient with bilateral high grade carotid stenosis: a case report

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    <p>Abstract</p> <p>Background</p> <p>Management of patients with co-existent coronary and carotid disease is a controversial and challenging issue. The risk for stroke after coronary artery bypass grafting (CABG) in patients with hemodynamically significant carotid stenosis is up to 30%. In these patients a common practice is to proceed first with the restoration of cerebral perfusion and then perform the coronary revascularization. The rationale is that this strategy will reduce perioperative neurological morbidity and mortality. However, what happens when the carotid procedure is acutely complicated by cardiac instability which necessitates the interruption of the carotid procedure?</p> <p>Case report</p> <p>We describe a case of a patient with unstable angina and high grade asymptomatic bilateral carotid stenosis who underwent emergency combined CABG and carotid endarterectomy (CEA). Due to hemodynamic instability, ST-T changes, hypotension and bradycardia, upon completion of endarterectomy we placed a carotid shunt and the patient was put on cardiopulmonary bypass through median sternotomy. After triple CABG (duration of 90 minutes) we concluded the interrupted CEA procedure with primary closure of the carotid arteriotomy with the shunt in place. The postoperative course was uneventful and the patient was discharged after a week. In extreme cases with bilateral severe carotid stenosis and coronary artery disease where the carotid procedure should be interrupted, we suggest the use of carotid shunt which can provide adequate cerebral perfusion giving time to cardiac surgeon to perform the life saving cardiac procedure first.</p

    Organic chemistry of NH<sub>3</sub> and HCN induced by an atmospheric abnormal glow discharge in N<sub>2</sub>-CH<sub>4</sub> mixtures

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    The formation of the chemical products produced in an atmospheric glow discharge fed by a N2-CH4 gas mixture has been studied using Fourier Transform InfraRed (FTIR) and Optical Emission Spectrometry (OES). The measurements were carried out in a flowing regime at ambient temperature and pressure with CH4 concentrations ranging from 0.5% to 2%. In the recorded emission spectra the lines of the second positive system CN system and the first negative system of N2 were found to be the most intensive but atomic Hα, Hβ, and C (247 nm) lines were also observed. FTIR-measurements revealed HCN and NH3 to be the major products of the plasma with traces of C2H2. These same molecules have been detected in Titan's atmosphere and the present experiments may provide some novel insights into the chemical and physical mechanisms prevalent in Titan's atmosphere with these smaller species believed to be the precursors of heavier organic species in Titan's atmosphere and on its surface
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