Terahertz-frequency optical pulses can resonantly drive selected vibrational modes in solids and deform their crystal structures. In complex oxides, this method has been used to melt electronic ...order, drive insulator-to-metal transitions and induce superconductivity. Strikingly, coherent interlayer transport strongly reminiscent of superconductivity can be transiently induced up to room temperature (300 kelvin) in YBa2Cu3O6+x (refs 9, 10). Here we report the crystal structure of this exotic non-equilibrium state, determined by femtosecond X-ray diffraction and ab initio density functional theory calculations. We find that nonlinear lattice excitation in normal-state YBa2Cu3O6+x at above the transition temperature of 52 kelvin causes a simultaneous increase and decrease in the Cu-O2 intra-bilayer and, respectively, inter-bilayer distances, accompanied by anisotropic changes in the in-plane O-Cu-O bond buckling. Density functional theory calculations indicate that these motions cause drastic changes in the electronic structure. Among these, the enhancement in the character of the in-plane electronic structure is likely to favour superconductivity.
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DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The phytochemical investigation of the lichen Parmotrema sancti‐angelii afforded three racemic compounds, sanctis A–C, which feature an original dibenzo‐2,8‐dioxabicyclo3.3.1nonane scaffold. These ...compounds were structurally characterized by extensive NMR spectroscopy analyses, comparison between experimental and theoretical NMR spectroscopic data, and X‐ray crystallography. These metabolites are similar to procyanidin A and display a methyl group instead of a pendant aromatic ring at C‐9, a so far unprecedented structural feature. A biosynthetic route to sanctis A–C is proposed.
Three racemic pairs of procyanidin analogues (sanctis A–C) are isolated from the lichen Parmotrema sancti‐angelii along with eight other known compounds. These new metabolites all display a new carbon skeleton.
For the first plasma diagnostics to be deployed at the Laser Megajoule (LMJ), the Commissariat à l'Energie Atomique (CEA) is developing ultrafast x-ray imaging cameras to analyze spatial and ...temporal evolution of laser-plasma interaction parameters. These cameras, which operate in the target chamber vacuum, are composed of a one-dimensional (1-D) streak or a two-dimensional (2-D) gated detector, power supply units, control electronic modules, and a charge-coupled device (CCD) readout system. In order to optimize their definition and to ensure easy maintenance, these cameras are packaged inside a hermetically sealed chamber comprised of a pressurized box (air box), which also enable the electronics to operate at atmospheric pressure and provide protection of the camera against the harsh operating environment induced by fluxes of neutrons, x-rays and gamma rays, and electromagnetic radiations. This paper introduces the work led by CEA concerning the development of the air box which integrates the x-ray streak and framing cameras for the first LMJ plasma diagnostics experiments, with regard to the integration and operational constraints of the facility.
In a randomized trial of patients with primary biliary cholangitis, bezafibrate and ursodeoxycholic acid resulted in a higher rate of complete biochemical response than ursodeoxycholic acid alone. ...Bezafibrate was associated with increases in creatinine and myalgias.
Summary Purpose: A phase II–III randomised study to compare safety and efficacy of an oxaliplatin/cyclophosphamide (OXAC) combination, vs. the reference combination of cisplatin/cyclophosphamide ...(CPC), in untreated advanced ovarian cancer patients. Patients and methods: 182 patients were enrolled, of whom 177 were treated; 86 with OXAC (130 mg/m2 oxaliplatin two-hour intravenous (i.v.) infusion, 1000 mg/m2 cyclophosphamide two-hour i.v. infusion), and 91 with CPC (100 mg/m2 cisplatin one-hour i.v. infusion, 1000 mg/m2 cyclophosphamide two-hour i.v. infusion). Treatment cycles were repeated every three weeks (maximum of six cycles). Results: The main toxicities, which were significantly less severe in the OXAC arm, were myelosuppression and vomiting, including (OXAC vs CPC, % patients): grade 3–4 leuko- penia (37% vs. 56%), and anaemia (7% vs. 32%), with blood transfusions in 8% vs. 21%. In the OXAC arm. 64% of surgically assessable patients and 33% of clinically assessable patients achieved an objective response. In the CPC arm. 67% patients achieved a surgical response and 42% achieved an objective clinical response. In the OXAC and CPC arms, median progression free-survival was 13.0 and 13.3 months, and overall survival was 36.0 and 25.1 months respectively, without statistically significant difference. Conclusion: The activity and time-related parameters of the OXAC and CPC combinations in advanced ovarian cancer patients, are comparable. Combined with the better safety profile of the oxaliplatin-containing regimen, this confirms the interest of oxaliplatin combined with active new agents in this indication.
Strongly correlated electron systems often exhibit very strong interactions between structural and electronic degrees of freedom that lead to complex and interesting phase diagrams. For technological ...applications of these materials it is important to learn how to drive transitions from one phase to another. A key question here is the ultimate speed of such phase transitions, and to understand how a phase transition evolves in the time domain. Here we apply time-resolved X-ray diffraction to directly measure the changes in long-range order during ultrafast melting of the charge and orbitally ordered phase in a perovskite manganite. We find that although the actual change in crystal symmetry associated with this transition occurs over different timescales characteristic of the many electronic and vibrational coordinates of the system, the dynamics of the phase transformation can be well described using a single time-dependent 'order parameter' that depends exclusively on the electronic excitation.
We use femtosecond time-resolved hard x-ray scattering to detect coherent acoustic phonons generated during ultrafast laser excitation of ferromagnetic bcc Fe films grown on MgO(001). We observe the ...coherent longitudinal-acoustic phonons as a function of wave vector through analysis of the temporal oscillations in the x-ray scattering signal. The width of the extracted strain wave front associated with this coherent motion is ~ 100 fs. An effective electronic Gruneisen parameter is extracted within a two-temperature model. However, ab initio calculations show that the phonons are nonthermal on the time scale of the experiment, which calls into question the validity of extracting physical constants by fitting such a two-temperature model.
Abstract Background There is growing evidence from animal models that intermittent hypoxemia (IH) may induce dyslipidemia. Altered lipid metabolism may contribute to the increased cardiovascular risk ...observed in obstructive sleep apnea (OSA). In this multisite, cross-sectional study, we tested the hypothesis that there is an independent association between nocturnal IH and dyslipidemia in OSA. Methods Fasting serum lipid levels were measured in 2,081 patients (638 women) undergoing nocturnal recording for clinical suspicion of OSA. Multivariate regression analyses were performed to evaluate the independent associations between oxygen desaturation index (ODI) and lipid profile after adjustment for potential confounders, including components of the metabolic syndrome (MS) or the MS itself. Adjusted OR for metabolic dyslipidemia (triglycerides TG ≥ 150 mg/dL and high-density lipoprotein cholesterol HDL-C ≤ 50 mg/dL for women and ≤ 40 mg/dL for men) according to quartiles of ODI were determined by logistic regression. Results Total cholesterol and low-density lipoprotein cholesterol were not associated with ODI. In contrast, nocturnal IH and OSA severity were associated with higher TG levels and lower HDL-C levels after adjustment for confounding factors. The association between ODI and TG and HDL-C levels was independent of the MS. Adjusted OR (95% CIs) for metabolic dyslipidemia were 1 (reference), 1.56 (1.24-1.96), 1.72 (1.29-2.29), and 1.93 (1.55-2.41) for ODI ≤ 7, > 7 to ≤ 18, > 18 to ≤ 38, and > 38, respectively ( P <.0001 for linear trend). Conclusions Nocturnal IH is independently associated with metabolic dyslipidemia, which may predispose patients with OSA to a higher risk of cardiovascular disease.
New racemic dispiranic polyketides, tsavoenones A (1), B (2) and C (3), having a novel 1,7-dioxadispiro4.0.4.4tetradecane scaffold were isolated from the foliose lichen Parmotrema tsavoense. These ...compounds were structurally elucidated by extensive NMR analyses, comparison between experimental and theoretical 13C NMR data and X-ray crystallography. A putative biosynthetic scenario for the formation of 1-3 from parmosidone D, a meta-depsidone previously isolated from the same lichen material, was proposed. Tested for its cytotoxicity, 1 displayed a moderate activity against human myelogenous leukemia K562 cell line with an IC50 value of 66 μg mL-1.
In this study, we compared the reliability of short-term resting heart rate (HR) variability (HRV) and postexercise parasympathetic reactivation (i.e., HR recovery (HRR) and HRV) indices following ...either submaximal or supramaximal exercise. On 4 different occasions, beat-to-beat HR was recorded in 15 healthy males (21.5 ± 1.4 yr) during 5 min of seated rest, followed by submaximal (Sub) and supramaximal (Supra) exercise bouts; both exercise bouts were followed by 5 min of seated recovery. Reliability of all HR-derived indices was assessed by the typical error of measurement expressed as a coefficient of variation (CV,%). CV for HRV indices ranged from 4 to 17%, 7 to 27% and 41 to 82% for time domain, spectral and ratio indices, respectively. The CV for HRR ranged from 15 to 32%. Spectral CVs for HRV were lower at rest compared with Supra (e.g., natural logarithm of the high frequency range (LnHF); 12.6 vs. 26.2%; P=0.02). HRR reliability was not different between Sub and Supra (25 vs. 14%; P=0.10). The present study found discrepancy in the CVs of vagal-related heart rate indices; a finding that should be appreciated when assessing changes in these variables. Further, Supra exercise was shown to worsen the reliability of HRV-spectral indices.
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