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Using one of the world most powerful laser facility, we demonstrate for the first time that high-contrast multi-picosecond pulses are advantageous for proton acceleration. By extending the pulse duration from 1.5 to 6 ps with fixed laser intensity of 1018 W cm−2, the maximum proton energy is improved more than twice (from 13 to 33 MeV). At the same time, laser-energy conversion efficiency into the MeV protons is enhanced with an order of magnitude, achieving 5% for protons above 6 MeV with the 6 ps pulse duration. The proton energies observed are discussed using a plasma expansion model newly developed that takes the electron temperature evolution beyond the ponderomotive energy in the over picoseconds interaction into account. The present results are quite encouraging for realizing ion-driven fast ignition and novel ion beamlines.

To enhance the core heating efficiency in fast ignition laser fusion, the concept of relativistic electron beam guiding by external magnetic fields was evaluated by integrated simulations for FIREX class targets. For the cone-attached shell target case, the core heating performance is deteriorated by applying magnetic fields since the core is considerably deformed and the most of the fast electrons are reflected due to the magnetic mirror formed through the implosion. On the other hand, in the case of cone-attached solid ball target, the implosion is more stable under the kilo-tesla-class magnetic field. In addition, feasible magnetic field configuration is formed through the implosion. As the results, the core heating efficiency becomes double by magnetic guiding. The dependence of core heating properties on the heating pulse shot timing was also investigated for the solid ball target., Comment: 9pages, 12 figures, submitted to Plasma Physics and Controlled Fusion

Recent progress in the physics of fast ignition of fusion targets is reviewed here. Fundamental studies on hot electron energy transport show that the scheme looks promising if the heating pulse can be guided close enough to a compressed core. The idea of using cone-guided compression was first demonstrated experimentally under a Japan-UK collaboration. The use of the gold cone was extremely successful and showed a 10 3 neutron increase out of CD target implosion with a 300 J/0.5 ps enforced heating laser pulse. The heated temperature was close to 1 keV. In order to increase the temperature to 10 keV, a 10 kJ PW- laser system is necessary. Osaka University has started constructing such a laser system.

For enhancing the core heating efficiency in electron-driven fast ignition, we proposed the fast electron beam guiding using externally applied longitudinal magnetic fields. Based on the PIC simulations for the FIREX-class experiments, we demonstrated the sufficient beam guiding performance in the collisional dense plasma by kT-class external magnetic fields for the case with moderate mirror ratio (~, 11pages, 8figures

For enhancing the core heating efficiency in fast ignition laser fusion, we proposed the fast electron beam by externally-applied the kilo-tesla (kT) class longitudinal magnetic field. We evaluated the imploded core and the magnetic field profiles formed through the implosion dynamics by resistive MHD radiation hydro code. Using those profiles, the guiding effect was evaluated by fast electron transport simulations, which shows that in addition to the feasible field configuration (moderate mirror ratio), the kT-class magnetic field is required at the fast electron generation point. In this case, the significant enhancement in heating efficiency is expected.

The dependence of high-energy electron generation on the pulse duration of a high intensity LFEX laser was experimentally investigated. The LFEX laser (λ = 1.054 and intensity = 2.5 – 3 x 1018 W/cm2) pulses were focused on a 1 mm3 gold cubic block after reducing the intensities of the foot pulse and pedestal by using a plasma mirror. The full width at half maximum (FWHM) duration of the intense laser pulse could be set to either 1.2 ps or 4 ps by temporally stacking four beams of the LFEX laser, for which the slope temperature of the high-energy electron distribution was 0.7 MeV and 1.4 MeV, respectively. The slope temperature increment cannot be explained without considering pulse duration effects on fast electron generation.

Hot electrons which are generated from targets irradiated by a high-intense laser are measured by two electron spectrometers (ESMs). However, total electron energy observed by the ESM is only less than 1%. Hot electrons are confined by self-fields due to the huge current. When an external magnetic field of several hundred Tesla is applied during the laser irradiation on targets, the ESM signals always increase. In the simulation, the same result can be obtained. The reason is that the Alfven limit can be mitigated due to the external longitudinal magnetic field.

The traditional fast ignition scheme is that a compressed core created by an imploding laser is auxiliary heated and ignited by the hot electrons (produced by a short pulse laser guided through the cone and guided under-dense plasma). However sufficient heating has not be achieved because the hot electron energy is too high and dissipated in the cone, the angular divergence of the hot electron is too large, and the distance from the generation point to the core is too long. Here we clarify the problems of fast ignition by observation of the hot-electron spectra.

We proposed the new laser arrangement to implode a target, a 12-beam implosion, and tried it in a fast ignition integration experiments. The concept of the 12-beam implosion is as follows. The three laser beams near a cone are shifted not to irradiate a cone and a long gold cone is used to prevent the irradiation of those three laser beams with fundamental frequency. In experiments, time-resolved two-dimensional X-ray images of an imploded core plasma were obtained by an X-ray framing camera. It is found that the spherical symmetry of the imploded core plasma is improved and the motion of the imploded core plasma towards the cone is suppressed in half in the 12-beam implosion. We believe that the 12-beam implosion will become a useful concept in controlling the imploded core plasma.

The majority of human urinary stones are primarily composed of calcium salts. Although normal urine is frequently supersaturated with respect to calcium oxalate, most humans do not form stones. Inhibitors are among the multiple factors that may influence the complex process of urinary stone formation. We have isolated an inhibitor of calcium oxalate crystal growth from human urine by monoclonal antibody immunoaffinity chromatography. The N-terminal amino acid sequence and acidic amino acid content of this aspartic acid-rich protein, uropontin, are similar to those of other pontin proteins from bone, plasma, breast milk, and cells. The inhibitory effect of uropontin on calcium oxalate crystal growth in vitro supports the concept that pontins may have a regulatory role. This function would be analogous to that of other members of the aspartic acid-rich protein superfamily, which stereospecifically regulate the mineralization fronts of calcium-containing crystals.

The generation of a 1.052- mu m laser pulse of 3.5-ps duration and 28-J energy by fiber-grating chirped-pulse amplification in a large-aperture Nd-glass laser system is reported. A novel technique that significantly improves the contrast ratio was used, resulting in a pulse with 8-TW peak power and a contrast ratio of better than 900, limited by the dynamic range of the detection system. The high contrast ratio was obtained by selecting only only the central portion of the frequency-chirped pulse where the chirp is positive and linear. The high-intensity compressed pulse thus generated was frequency-upconverted to 526 nm with a 40% conversion efficiency. >

In view of the ability of calmodulin to bind vasoactive intestinal peptide (VIP) and growth-hormone-releasing factor (GRF) with high affinity [Stallwood, Brugger, Baggenstoss, Stemmer, Shiraga, Landers and Paul (1992) J. Biol. Chem. 267, 19617-19621], the effects of these neuropeptides on a model calmodulin-dependent enzyme, myosin light-chain kinase (MLCK), were studied. Both peptides were potent inhibitors of MLCK activity. The inhibition of enzyme activity by VIP and GRF was progressively overcome with increasing calmodulin concentrations, with no inhibition observed at a saturating calmodulin concentration. Nanomolar concentrations of MLCK blocked the formation of calmodulin-[125I-Tyr10]VIP complexes. These data provide support for a functional role of VIP and GRF binding by calmodulin.

The high energetic electron measurement is one of the most important issues to research the ignition mechanism in the Fast Ignition Realization EXperiment Project. It is also important for the energy spectra with angular distribution because the electron spread is different by the target design. Therefore we have been developed the compact Electron SpectroMeter so as to be installed on different angular potions. We have performed the calibration using L-band LINAC in the Institute of Scientific and Industrial Research, Osaka University. The analyzer has been tested to measure energetic electrons from the aluminum and gold plain targets irradiated by LFEX laser (maximum energy of 10 kJ) up to 800 J. The electron measurement has been performed at the integrated experiments using CD-shell with Au cone. The non-Maxwellian spectrum can be observed when the effective core heating by the electron is occurred.

A vasoactive intestinal peptide (VIP)-binding protein purified from guinea pig lung membranes (p18) was digested with trypsin, and the amino acid sequence of the peptide fragments was determined. The sequence of six tryptic fragments of p18 was identical with subsequences present in mammalian calmodulin. Authentic porcine brain calmodulin and p18 co-migrated on an sodium dodecyl sulfate-electrophoresis gel and displayed identical chromatographic behavior on a reverse phase high performance liquid chromatography column. The VIP-binding properties of p18 and calmodulin were indistinguishable. Both proteins displayed saturable and apparent high affinity binding of VIP, evidenced by potent inhibition of complexation with [Tyr10-125I]VIP by unlabeled VIP (IC50 = 6.0-8.1 nM). Rat growth hormone releasing factor and a C terminally extended form of VIP ([Leu17]VIP-GKR) also displayed potent inhibition of the binding (IC50 = 6.4 and 4 nM, respectively). These neuropeptides are potential modulators of calmodulin function.

In a Fast Ignition Realization Experiment (FIREX), measurement of the primary and the secondary neutron yield is one of the key diagnostics. However, gamma-ray background generated by an ultra-short pulse laser irradiation makes it difficult to measure the neutron yield in the fast ignition experiment. We adopted a bubble neutron detector as a promising gamma-insensitive detector to be developed and started to examine the feasibility of the detector using commercially available dosimeters provided from BTI inc. [1].

Soft X-ray laser experiments recently carried out using the Gekko MII glass laser facility at the Institute of Laser Engineering, Osaka University, are described. Hydrogenic and lithiumlike lasing schemes in recombining plasmas were investigated using foil targets exploded with line-focused 532 nm laser radiation of approximately 100 J energy. In a preliminary study, time-integrated emissions of Balmer- alpha transitions in C/sup 8+/ and O/sup 7+/ and 5-3 transitions in Al/sup 10+/ were found to increase nonlinearly with increasing target length, yielding gain coefficients of G=0.9 to 2.3 cm/sup -1/. In a subsequent, more refined study, which included time-resolved measurements, the authors obtained a gain of G=2 cm/sup -1/ and a gain-length product GL=3 for the Balmer- alpha transition in F/sup 8+/ at 80.9 AA. >

Single nephron filtration rate of albumin (SNGFRAlb) was measured in remnant nephrons of Munich-Wistar rats 4-6 wk after subtotal nephrectomy (NPX). Serial thin-section histological analysis was then conducted on the same glomeruli by light microscopy. SNGFRAlb ranged from 1 to 15 times normal. However, a direct relationship between abnormalities of structure and function was not seen, e.g. the glomeruli with the fewest structural abnormalities and marked hyperfiltration often had the highest SNGFRAlb. Moreover, the majority of glomeruli had minimal structural abnormalities. Normalization of the markedly elevated glomerular capillary pressure (PGC) in these glomeruli was accomplished by acute intravenous infusion of verapamil, which decreased SNGFRAlb by 9-83% without affecting the single nephron filtration rate of water (SNGFRH2O). 1-2 wk after subtotal NPX, all glomeruli were hyperfiltering and had elevated PGC. The fractional clearance of larger (greater than 36 A) dextrans was selectively increased in these glomeruli that lacked discernible damage by light microscopy. Verapamil normalized PGC, reduced proteinuria to 48 +/- 4% of baseline, and improved glomerular size selectivity without altering SNGFRH2O. Proteinuria after subtotal NPX thus originates largely from glomeruli with minimal structural abnormalities. The defect in size selectivity is largely attributed to the prevailing high PGC, producing large, nonselective channels on the glomerular capillary wall. The observations raise the possibility that in chronic renal diseases, the reduction in proteinuria often seen after therapeutic measures, including antihypertensive medication, may reflect their functional effect on the relatively intact glomeruli rather than their structure-sparing effect on severely damaged glomeruli, which contribute little to the proteinuria.