Liquid Structure of Tantalum under Internal Negative Pressure.

In situ femtosecond x-ray diffraction measurements and ab initio molecular dynamics simulations were performed to study the liquid structure of tantalum shock released from several hundred gigapascals (GPa) on the nanosecond timescale. The results show that the internal negative pressure applied to the liquid tantalum reached -5.6 (0.8) GPa, suggesting the existence of a liquid-gas mixing state due to cavitation. This is the first direct evidence to prove the classical nucleation theory which predicts that liquids with high surface tension can support GPa regime tensile stress.

Ultrafast time-resolved 2D imaging of laser-driven fast electron transport in solid density matter using an x-ray free electron laser.

High-power, short-pulse laser-driven fast electrons can rapidly heat and ionize a high-density target before it hydrodynamically expands. The transport of such electrons within a solid target has been studied using two-dimensional (2D) imaging of electron-induced Kα radiation. However, it is currently limited to no or picosecond scale temporal resolutions. Here, we demonstrate femtosecond time-resolved 2D imaging of fast electron transport in a solid copper foil using the SACLA x-ray free electron laser (XFEL). An unfocused collimated x-ray beam produced transmission images with sub-micron and ∼10 fs resolutions. The XFEL beam, tuned to its photon energy slightly above the Cu K-edge, enabled 2D imaging of transmission changes induced by electron isochoric heating. Time-resolved measurements obtained by varying the time delay between the x-ray probe and the optical laser show that the signature of the electron-heated region expands at ∼25% of the speed of light in a picosecond duration. Time-integrated Cu Kα images support the electron energy and propagation distance observed with the transmission imaging. The x-ray near-edge transmission imaging with a tunable XFEL beam could be broadly applicable for imaging isochorically heated targets by laser-driven relativistic electrons, energetic protons, or an intense x-ray beam.

Development of an experimental platform for the investigation of laser-plasma interaction in conditions relevant to shock ignition regime.

The shock ignition (SI) approach to inertial confinement fusion is a promising scheme for achieving energy production by nuclear fusion. SI relies on using a high intensity laser pulse (≈1016 W/cm2, with a duration of several hundred ps) at the end of the fuel compression stage. However, during laser-plasma interaction (LPI), several parametric instabilities, such as stimulated Raman scattering and two plasmon decay, nonlinearly generate hot electrons (HEs). The whole behavior of HE under SI conditions, including their generation, transport, and final absorption, is still unclear and needs further experimental investigation. This paper focuses on the development of an experimental platform for SI-related experiments, which simultaneously makes use of multiple diagnostics to characterize LPI and HE generation, transport, and energy deposition. Such diagnostics include optical spectrometers, streaked optical shadowgraph, an x-ray pinhole camera, a two-dimensional x-ray imager, a Cu Kα line spectrometer, two hot-electron spectrometers, a hard x-ray (bremsstrahlung) detector, and a streaked optical pyrometer. Diagnostics successfully operated simultaneously in single-shot mode, revealing the features of HEs under SI-relevant conditions.

Bremsstrahlung cannon design for shock ignition relevant regime.

We report on the optimization of a BremsStrahlung Cannon (BSC) design for the investigation of laser-driven fast electron populations in a shock ignition relevant experimental campaign at the Laser Megajoule-PETawatt Aquitaine Laser facility. In this regime with laser intensities of 1015 W/cm2-1016 W/cm2, fast electrons with energies ≤100 keV are expected to be generated through Stimulated Raman Scattering (SRS) and Two Plasmon Decay (TPD) instabilities. The main purpose of the BSC in our experiment is to identify the contribution to x-ray emission from bremsstrahlung of fast electrons originating from SRS and TPD, with expected temperatures of 40 keV and 95 keV, respectively. Data analysis and reconstruction of the distributions of x-ray photons incident on the BSC are described.

Determination of distances from tyrosine D to QA and chlorophyllZ in photosystem II studied by '2+1' pulsed EPR

A '2+1' pulse sequence electron spin echo (ESE) method was applied to measure the dipole interactions between the tyrosine YD+ and QA- in Photosystem II (PS II). In a CN--treated PS II, QA- EPR signal was observed at g=2.0045 position, because the non-heme Fe(II) was converted into a low-spin (S=0) state. The radical pair of YD+QA- was trapped by illumination for 8 min at 273 K, followed by dark adaptation for 3 min and freezing into 77 K. By using a proton matrix ENDOR, these trapped radicals were confirmed to be YD+ and QA-, respectively. The distance between the radical pair was estimated from the dipole interaction constant fitted to the observed '2+1' ESE time profile. The distance of YD+-QA- is determined to be 38.8+/-1.1 A. The magnetic dipole interaction between YD+ and ChlZ+ was determined in a Tris-treated PS II in which ChlZ+ was generated by illumination at 200 K for 10 min. The YD+-ChlZ+ distance was estimated to be 29.4+/-0.5 A. Copyright 1998 Elsevier Science B.V.

Leukotoxin (9, 10-epoxy-12-octadecenoate) impairs energy and redox state of isolated perfused rat lung.

We investigated the perturbation of energy balance and redox state in leukotoxin (9, 10-epoxy-12octadecenoate) (Lx)- and endothelin-1 (ET-1)-induced lung injury, using isolated perfused rat lungs. To examine any relationship between these parameters, intracellular levels of adenine nucleotides, pyridine coenzymes and glutathione were determined by reversed-phase high-performance liquid chromatography (HPLC) in the freeze-dried tissues of isolated rat lungs. The tissue samples were perfused with a physiological salt solution containing either Lx only, Lx plus NG-monomethyl-L-arginine (L-NMMA), Lx plus NG-monomethyl-D-arginine (D-NMMA), Lx plus superoxide dismutase (SOD) or ET-1 only. In isolated perfused lung tissue, 10 mol of Lx caused permeability-increased lung injury, and 10 nM of ET-1, which caused a comparable increase in wet lung weight, evoked pulmonary capillary hypertensive lung injury. Lx-injured lungs showed decreases in the contents of ATP, NADPH, NADH, reduced glutathione (GSH), (2ATP + ADP)/2(ATP + ADP + AMP) ratio (energy charge) and NADH/NAD+ ratio, and increased the contents of ADP and AMP compared with the vehicle control and ET-1-injured lungs. Such effects of Lx were significantly attenuated by pretreatment with 0.4 mM L-NMMA or 500 units/ml of SOD, but not with 0.4 mM D-NMMA. On the other hand, the ET-1-injured lung evidenced decreased tissue GSH. These findings indicate that Lx shifted the lung redox state toward oxidation and that Lx-induced lung injury was involved in the imbalance of the energy and redox state via production of nitric oxide and/or superoxide anion.

Pharmacological characterization of endothelin-induced rat pulmonary arterial dilatation.

1. The aim of study was to characterize endothelin (ET)-induced vasodilation in isolated extrapulmonary rat arteries (EPA) and in intrapulmonary arteries (IPA) preconstricted with 1 microM phenylephrine. 2. The ET-3 (1 nM-100 nM)- and ET-1 (10 nM-100 nM)-induced transient vasodilatations in EPA were more potent than those in IPA. The vasodilatation induced by ET-3 (100 nM) was larger than that induced by ET-1 (100 nM). 3. Both the ETB antagonist, BQ788 (3 microM) and or endothelium denudation, but not the ETA antagonist, BQ123 (3 microM), abolished the vasodilation induced by ET-1 or ET-3 (100 nM each) in EPA and in IPA. The ATP-sensitive K + channel blocker, glibenclamide (20 microM) and the nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (L-NMMA, 1 mM) suppressed the ET-induced vasodilatation in EPA and in IPA. 4. We conclude that the vasodilatation induced by endothelins is markedly reduced in rat isolated IPA, and suggest that the endothelial ETB-mediated vasodilatation varies depending on rat pulmonary arterial regions. Furthermore, ETB-mediated vasodilatation involves activation of ATP-sensitive K+ channels and of nitric oxide synthase in rat isolated EPA and IPA.

Feed-out of rear surface perturbation due to rarefaction wave in laser-irradiated targets

We report experimental results on hydrodynamic perturbation transfer from the rear to the front of laser-irradiated targets. Flat polystyrene foils with rear-surface perturbations were irradiated by partially coherent light. We observed phase inversion of the rear surface after the shock breakout at the rear surface. Perturbations on the laser-irradiated surface arose due to the rippled rarefaction wave. Experimental results were well reproduced by a simple model with unperturbed hydrodynamic quantities calculated from the one-dimensional simulation.

Endothelin-1 potentiates leukotoxin-induced edematous lung injury.

We tested the hypothesis that leukotoxin (Lx), a cytochrome P-450-dependent linoleate product of leukocytes, can stimulate the release of endothelin-1 (ET-1) from the lung and further that exogenous ET-1 synergizes with Lx to produce edematous lung injury. In isolated rat lungs perfused with Earle's balanced salt solution, Lx (10 mumol) alone caused lung edema and increased the perfusate and lung tissue ET-1 levels. The combination of ET-1 (5 nM) and Lx (5 mumol), at concentrations that by themselves did not increase wet lung weight, significantly increased wet lung weight, wet-to-dry lung weight ratio, as well as the lung effluent lactate dehydrogenase activity. Pretreatment with BQ-123 (5 x 10(-6) M), an endothelin A receptor antagonist that significantly attenuated the ET-1 (5 nM)-induced increase in pulmonary arterial pressure (Ppa) and pulmonary capillary pressure (Ppc), suppressed the edematous lung injury generated by the combination of ET-1 and Lx, suggesting that the edema-enhancing effect of ET-1 in Lx-treated lungs occurred through endothelin A receptor-dependent elevation of Ppa and Ppc. Elevation of the pulmonary venous pressure in Lx-treated lungs (13.5 cmH2O) mimicked the effect of ET-1 on Ppa and Ppc and produced a degree of lung edema that was comparable to that after combined ET-1 + Lx treatment but without increase in the perfusate lactate dehydrogenase. These data support the idea that ET-1 and Lx promote lung edema in a synergistic fashion.

Perturbation transfer from the front to rear surface of laser-irradiated targets.

We present experimental results on the perturbation transfer of laser irradiated planar foils. Perturbed polystyrene foils were irradiated directly by laser at intensity of 6 x 10(13) W/cm(2). We measured perturbations on the foils by side-on x-ray backlighting technique. Perturbations on the rear surface due to the rippled shock front were observed just after the shock breakout. We also observed feed-through of perturbations on the laser-irradiated surface that grows due to the Rayleigh-Taylor instability.

The relationship between low Km aldehyde dehydrogenase phenotype and drinking behavior in Japanese.

The relationship between the low Km aldehyde dehydrogenase (ALDH2) phenotype determined by the isoelectric focusing of hair root lysates, facial flushing and alcohol drinking patterns in Japanese (N = 282) was examined. Men who had inactive ALDH2 drank significantly less alcohol than those with active ALDH2. Although the effect was less noticeable, a similar relationship was detected in women. Two types of flushing responses were determined: one due to the inactive ALDH2, the other unrelated to this variant form of the isozyme. A striking difference between these flushing types, in terms of the inhibitory influence over drinking patterns, was noted. Nearly 86% of the subjects who reported always flushing in the face were shown to have inactive ALDH2, whereas infrequent flushing and absence of flushing were associated with active ALDH2. Thus, facial flushing may be used as an indicator of ALDH2 phenotype.

Sound velocity measurements by x-ray shadowgraph technique for melting phenomena at ultrahigh-pressure regime.

Developments in measuring sound velocity of matter under ultrahigh pressure are described. We employed a time-resolved x-ray shadowgraph technique to measure the sound velocity of shock-compressed diamond and iron foils at around melt. The sound velocity significantly dropped at melting, a behavior that has been difficult to clarify by conventional measurements by subtracting particle velocity from shock velocity (u(s) - u(p)). In addition to sound velocity, other important parameters were also obtained simultaneously.

Experimental evidence of impact ignition: 100-fold increase of neutron yield by impactor collision.

We performed integrated experiments on impact ignition, in which a portion of a deuterated polystyrene (CD) shell was accelerated to about 600 km/s and was collided with precompressed CD fuel. The kinetic energy of the impactor was efficiently converted into thermal energy generating a temperature of about 1.6 keV. We achieved a two-order-of-magnitude increase in the neutron yield by optimizing the timing of the impact collision, demonstrating the high potential of impact ignition for fusion energy production.

Streaked x-ray backlighting with twin-slit imager for study of density profile and trajectory of low-density foam target filled with deuterium liquid.

Low-density plastic foam filled with liquid deuterium is one of the candidates for inertial fusion target. Density profile and trajectory of 527 nm laser-irradiated planer foam-deuterium target in the acceleration phase were observed with streaked side-on x-ray backlighting. An x-ray imager employing twin slits coupled to an x-ray streak camera was used to simultaneously observe three images of the target: self-emission from the target, x-ray backlighter profile, and the backlit target. The experimentally obtained density profile and trajectory were in good agreement with predictions by one-dimensional hydrodynamic simulation code ILESTA-1D.

Comprehensive diagnosis of growth rates of the ablative Rayleigh-Taylor instability.

The growth rate of the ablative Rayleigh-Taylor instability is approximated by gamma = square root[kg/(1 + kL)] - beta km/rho(a), where k is the perturbation wave number, g the gravity, L the density scale length, m the mass ablation rate, and rho(a) the peak target density. The coefficient beta was evaluated for the first time by measuring all quantities of this formula except for L, which was taken from the simulation. Although the experimental value of beta = 1.2+/-0.7 at short perturbation wavelengths is in reasonably good agreement with the theoretical prediction of beta = 1.7, it is found to be larger than the prediction at long wavelengths.

Randomised controlled trial of swaddling versus massage in the management of excessive crying in infants with cerebral injuries.

BACKGROUND: Infants with neonatal cerebral insults are susceptible to excessive crying as a result of difficulties with self-regulation. AIMS: To compare the effectiveness of swaddling versus massage therapy in the management of excessive crying of infants with cerebral insults. METHODS: Randomised three-week parallel comparison of the efficacy of two intervention methods. Infants with symptoms of troublesome crying and their parents were randomly assigned to a swaddling intervention group (n = 13) or a massage intervention group (n = 12). RESULTS: The amount of total daily crying decreased significantly in the swaddling group, but did not decrease significantly in the massage group. Infant behavioural profiles and maternal anxiety levels improved significantly in the swaddling group post-intervention. Parents in the swaddling group were more satisfied with the effectiveness of the intervention in reducing crying than parents in the massage group. CONCLUSION: Results indicate that swaddling may be more effective than massage intervention in reducing crying in infants with cerebral injuries.

[Lung injury and pulmonary vascular endothelial cell injury].

Pulmonary vascular endothelial cells are an important barrier that helps keep lung tissue intact. These cells are exposed to potentially injurious cells and to harmful mediators that are produced in or released into the blood. The endothelial cells may then be stimulated and injured. Stimulated and injured pulmonary vascular endothelial cells can themselves produce and release injury-promoting mediators. Using isolated perfused rat lungs and cultured human pulmonary endothelial cells, we assessed the effect of neutrophil-derived injurious mediators, leukotoxin, and neutrophil elastase on the pulmonary endothelium. Both mediators caused high-permeability pulmonary edema in the isolated lungs and caused dose-dependent and time-dependent damage in the cell cultures. Injury due to leukotoxin was suppressed in the presence of LNMMA or superoxide dismutase and injury due to neutrophil elastase was suppressed by neutrophil elastase inhibitors. These data indicate that these mediators cause lung injury via different mechanisms and that they may synergistically evoke clinical lung injury.