Electrostatic shock acceleration of ions in near-critical-density plasma driven by a femtosecond petawatt laser.

With the recent advances in ultrahigh intensity lasers, exotic astrophysical phenomena can be investigated in laboratory environments. Collisionless shock in a plasma, prevalent in astrophysical events, is produced when a strong electric or electromagnetic force induces a shock structure in a time scale shorter than the collision time of charged particles. A near-critical-density (NCD) plasma, generated with an intense femtosecond laser, can be utilized to excite a collisionless shock due to its efficient and rapid energy absorption.

Ground state in E ⊗ e Jahn-Teller and Renner-Teller systems: Account of nonadiabaticity.

The ground and lower excited states of an E⊗e Jahn-Teller system with linear and quadratic vibronic coupling are considered, taking nonadiabaticity into account. Our calculations confirm a common opinion that in the case of a weak quadratic coupling, the ground state is doubly degenerate and the first excited state is nondegenerate for any linear coupling. However, with increasing quadratic coupling for weak linear coupling, the nondegenerate state becomes the ground state.

Time-dependent Jahn-Teller problem: phonon-induced relaxation through conical intersection.

A theoretical study of time-dependent dynamical Jahn-Teller effect in an impurity center in a solid is presented. We are considering the relaxation of excited states in the E⊗e-problem through the conical intersection of the potential energy. A strict quantum-mechanical treatment of vibronic interactions with both the main Jahn-Teller active vibration and the nontotally symmetric phonons causing the energy loss is given.

Effective generation of the spread-out-Bragg peak from the laser accelerated proton beams using a carbon-proton mixed target.

Conventional laser accelerated proton beam has broad energy spectra. It is not suitable for clinical use directly, so it is necessary for employing energy selection system. However, in the conventional laser accelerated proton system, the intensity of the proton beams in the low energy regime is higher than that in the high energy regime.

Transition of proton energy scaling using an ultrathin target irradiated by linearly polarized femtosecond laser pulses.

Particle acceleration using ultraintense, ultrashort laser pulses is one of the most attractive topics in relativistic laser-plasma research. We report proton and/or ion acceleration in the intensity range of 5×10(19) to 3.3×10(20) W/cm2 by irradiating linearly polarized, 30-fs laser pulses on 10-to 100-nm-thick polymer targets.

Enhancement of electron energy to the multi-GeV regime by a dual-stage laser-wakefield accelerator pumped by petawatt laser pulses.

Laser-wakefield acceleration offers the promise of a compact electron accelerator for generating a multi-GeV electron beam using the huge field gradient induced by an intense laser pulse, compared to conventional rf accelerators. However, the energy and quality of the electron beam from the laser-wakefield accelerator have been limited by the power of the driving laser pulses and interaction properties in the target medium. Recent progress in laser technology has resulted in the realization of a petawatt (PW) femtosecond laser, which offers new capabilities for research on laser-wakefield acceleration.

Nonadiabaticity in a Jahn-Teller system probed by absorption and resonance Raman scattering.

A theory of absorption and resonance Raman scattering of impurity centers in crystals with E⊗e-type Jahn-Teller effect in the excited state is presented. The vibronic interaction with non-totally symmetric local or pseudolocal modes and with a continuum of bath modes (phonons) is considered. A number of specific quantum effects, such as the nonadiabaticity-induced enhancement of the Raman scattering at high-energy excitation, the size effect of the final state, the interference of different channels of scattering, the Fermi resonances in the conical intersection, and others, were shown to become apparent in the calculated spectra.

Relativistic frequency upshift to the extreme ultraviolet regime using self-induced oscillatory flying mirrors.

Coherent short-wavelength radiation from laser-plasma interactions is of increasing interest in disciplines including ultrafast biomolecular imaging and attosecond physics. Using solid targets instead of atomic gases could enable the generation of coherent extreme ultraviolet radiation with higher energy and more energetic photons. Here we present the generation of extreme ultraviolet radiation through coherent high-harmonic generation from self-induced oscillatory flying mirrors--a new-generation mechanism established in a long underdense plasma on a solid target.

Characteristics of relativistic electron mirrors generated by an ultrashort nonadiabatic laser pulse from a nanofilm.

For controllable generation of an isolated attosecond relativistic electron bunch [relativistic electron mirror (REM)] with nearly solid-state density, we proposed [V. V. Kulagin, Phys.

Ion spectrometer composed of time-of-flight and Thomson parabola spectrometers for simultaneous characterization of laser-driven ions.

An ion spectrometer, composed of a time-of-flight spectrometer (TOFS) and a Thomson parabola spectrometer (TPS), has been developed to measure energy spectra and to analyze species of laser-driven ions. Two spectrometers can be operated simultaneously, thereby facilitate to compare the independently measured data and to combine advantages of each spectrometer. Real-time and shot-to-shot characterizations have been possible with the TOFS, and species of ions can be analyzed with the TPS.

Tympanoplasty, with or without mastoidectomy, is highly effective for treatment of chronic otitis media in children.

Conclusion: The overall success rate of tympanoplasty, with or without mastoidectomy, in the treatment of chronic pediatric otitis media, was high and did not depend on patient age, the status of the contralateral ear, the inclusion or absence of surgical mastoidectomy, or the method of mastoidectomy (when this procedure was employed). Tympanoplasty may be expected to improve hearing in cases of chronic otitis media accompanied by perforation, but not in cases of cholesteatoma.

Objectives: This study analyzed the clinical features of pediatric patents with chronic otitis media undergoing tympanoplasty, with or without mastoidectomy.

[Short-term therapy with pegylated interferon plus ribavirin for the chronic hepatitis C genotype 2 patients].

Background/aims: The standard treatment for chronic hepatitis C patients infected with HCV genotype-2 is a combination of pegylated interferon alfa and ribavirin over a 24 week period. It is unclear if a shorter treatment duration is possible for patients showing a rapid virological response (RVR) without compromising the sustained virologic response (SVR) in Korea.

Methods: 42 patients chronically infected with the HCV genotype-2 were treated with peginterferon alfa-2a 180 mcg/wk plus ribavirin 800 mg/d for 24 weeks and followed up for 24 weeks.

2-[18F]-Fluoro-2-deoxy-D-glucose positron emission tomography as guidance for primary treatment in patients with advanced-stage resectable squamous cell carcinoma of the larynx and hypopharynx.

Background: High uptake of 2-[(18)F]-fluoro-2-deoxy-D-glucose (FDG) is associated with unfavorable results. Pretreatment FDG uptake was evaluated as a predictor of survival and guidance for primary surgery or radiotherapy (RT) in patients with squamous cell carcinoma (SCC) of the larynx and hypopharynx.

Materials And Methods: Seventy-nine consecutive patients with newly diagnosed advanced resectable SCC of the larynx and hypopharynx underwent FDG positron emission tomography (PET) before surgical resection plus RT and chemotherapy (surgery group, n=40) or RT with chemotherapy and surgical salvage (RT group, n=39).

Clinical manifestations and risk factors of children receiving triple ventilating tube insertions for treatment of recurrent otitis media with effusion.

Objective: Our goal was to determine risk factors for children receiving additional ventilating tube insertions after initial tube insertion and to determine the changes of clinical manifestations in children who have undergone 3 ventilating tube insertion procedures.

Study Design: We retrospectively analyzed medical and operation records of 423 young patients who had ventilating tube insertion because of chronic otitis media with effusion from January 1993 to December 1998. The single-operation group included patients who had 1 ventilating tube insertion only, and the triple-operation group included patients who received ventilating tube insertion 3 times because of recurring chronic otitis media with effusion.

Characterization of the 5'-flanking region of the human PTK6 gene.

PTK6 (also known as Brk) is a non-receptor protein tyrosine kinase, whose mRNA was expressed in the limited normal tissues such as colon and small intestine, and in breast carcinomas and breast cancer cell lines. The 813 bp region upstream from the translation initiation codon, which constitutes a functional promoter of the human PTK6 gene, was progressively deleted and fused to the luciferase reporter gene and transient expression of the resultant constructs was measured upon transfection into a breast carcinoma cell line, T-47D. Comparative analysis of luciferase activity revealed two major regions, -93 to -76 and -702 to -655, important for transcriptional regulation.

Chemistry of aminoiminomethanesulfinic and -sulfonic acids related to the toxicity of thioureas.

The reactions of aminoiminomethanesulfonic acid, phenylaminoiminomethanesulfonic acid, and N,N'-diphenylaminoiminomethanesulfonic acid in aqueous media at pH 7.4, 10, and 13-14 were investigated. At neutral pH hydrolysis to the corresponding urea was the major pathway for all three compounds.