Generation of strong optical field in soft X-ray region by using high-order harmonics

For further development of a variety of applications, one of the most important issues is the improvement of output harmonic energy and conversion efficiency. We review our work on the energy scaling of high-order harmonic generation based on phase-matching using a loosely focused beam. Our harmonic energy scaling method can be universally applied to harmonic generation in the neutral rare gas target. In addition, we demonstrate a new concept for spatial separation between the high-energy pump and harmonic beam to increase the available soft X-ray energy for the applications. This method is very simple and highly useful for not only high-order harmonic generation but also longitudinally pumped X-ray lasers. By combining the high-energy high harmonic source and new spatial separation method, we successfully demonstrate focusing of the soft X-ray beam with a peak intensity of 1/spl times/10/sup 14/ W/cm/sup 2/, which is to our knowledge the highest ever reported in the soft X-ray region.     

An eccentric‐K braced steel structure

This article from the Building Research Institute of the Japanese Ministry of Construction is based on a paper originally submitted as part of the US‐Japan co‐operative research programme. It discusses the results of inelastic tests on a steel frame six‐storey building at Tsukuba, where an eccentric‐K bracing system was tested after similar tests on concentric‐K bracing. The results validated the design philosophy of the eccentric‐K braced system, which was shown to have remarkable energy absorption capacity.     

Inhibition of malaria-infected erythrocytes by deoxyspergualin: effect on in vitro growth of malarial cultures

The aim of this study was to assess whether the psychobehavioral pattern alexithymia is related to coronary artery spasm. Alexithymia, deficient psychological awareness, was examined using the Minnesota Multiphasic Personality Inventory Alexithymia Scale in 100 patients with angina pectoris in whom coronary spasm, defined as > or = 99% coronary narrowing, was documented upon ergonovine provocation, and in 109 patients with chest pain syndrome who were shown to have almost normal coronaries without inducible coronary spasm on coronary angiogram (control group). Alexithymia was approximately twice as prevalent in the coronary spasm group (31%) as in the control group (14%) (p<0.01). Among various conventional risk factors including hyperlipidemia, obesity, diabetes mellitus, hypertension, hyperuricemia, or family history of ischemic heart disease, only male sex and smoking were more prevalent in the coronary spasm group than in the control group (p<0.001). The odds ratios of coronary spasm adjusted for all the other risk parameters including sex and age were 4.14 [95% confidence interval (CI) 1.81-9.47] for alexithymia and 2.38 (95, CI 1.18-4.82) for smoking. A psychobehavioral pattern, alexithymia, relates to coronary spasm. This relationship is independent of the conventional coronary risk factors.     

Apolipoprotein E Sendai (arginine 145-->proline): a new variant associated with lipoprotein glomerulopathy

Lipoprotein glomerulopathy (LPG) is a novel disease characterized by proteinuria, lipoprotein thrombi in the glomeruli, and increased concentration of plasma apolipoprotein (apo) E. It is believed that a genetic disorder of apo E may be present and associated with the disease. Three patients with LPG were examined in this study. The patients' DNA sequences were analyzed, and a nucleotide G to C point mutation in exon 4 of the apo E gene was confirmed in each patient. This missense mutation denotes amino acid substitution of the proline residue for arginine residue at position 145 of apo E. This variant (apo E Sendai) may cause a marked molecular conformational change of the apo E. These findings suggest that a novel variant is etiologically related to LPG.     

Left main coronary artery stenosis following aortic valve replacement using a solid coronary perfusion catheter: report of two cases

We experienced two cases of iatrogenic left main coronary artery stenosis (IOCS) following double (aortic and mitral) valve replacement (DVR). The solid coronary perfusion catheter may attribute IOCS, with grave consequence. There have been no IOCS since the time we exchanged a solid catheter for a soft one. One case, she was successfully treated percutaneous transluminal coronary angioplasty (PTCA), because she developed angina pectoris about 5 years after PTCA. But she developed angina pectoris again and angiographically left main coronary was severe stenotic. So she was undergone aorto coronary bypass grafting (CABG) to the left anterior descending. The other case, he developed angina pectoris about 3 months after DVR. He was treated with PTCA. Angiographically left mine coronary artery stenosis reduced 50% from 90%. Generally the treatment of IOCS is CABG, but we performed PTCA for 2 patients. Because we thought it was very hazardous for us to perform them open heart surgery. When it is very hazardous to perform patients open heart surgery, they need to be performed PTCA.     

Device performance of p-Ge MOSFETs at liquid nitrogen temperature

The device performance of p-channel Ge MOSFETs at liquid nitrogen temperature is reported and initial results of room temperature irradiation with 2-MeV electrons on the cryogenic device performance is described. It is shown that at 77 K an increase of the drain current and g_m is observed. This increase of the g_m can be explained by considering the balance between reduced phonon scattering on the one hand and increased Coulomb scattering by interface states, on the other. After irradiation, a slight negative shift of the threshold voltage and a decrease of the drain current for input and output characteristics have been observed together with a decrease of the transconductance (g_m).     

Oligomeric Structural Transition of HspB1 from Chinese Hamster

HspB1 is a mammalian sHsp that is ubiquitously expressed in almost all tissues and involved in regulating many vital functions. Although the recent crystal structure of human HspB1 showed that 24 monomers form the oligomeric complex of human HspB1 in a spherical configuration, the molecular architecture of HspB1 is still controversial. In this study, we examined the oligomeric structural change of CgHspB1 by sedimentation velocity analytical ultracentrifugation. At the low temperature of 4 °C, CgHspB1 exists as an 18-mer, probably a trimeric complex of hexamers. It is relatively unstable and partially dissociates into small oligomers, hexamers, and dodecamers. At elevated temperatures, the 24-mer was more stable than the 18-mer. The 24-mer is also in dynamic equilibrium with the dissociated oligomers in the hexameric unit. The hexamer further dissociates to dimers. The disulfide bond between conserved cysteine residues seems to be partly responsible for the stabilization of hexamers. The N-terminal domain is involved in the assembly of dimers and the interaction between hexamers. It is plausible that CgHspB1 expresses a chaperone function in the 24-mer structure.     

Spin-trapping reactions of a novel gauchetype radical trapper G-CYPMPO

Chemical reactions of a novel gauchetype spin trap, G-CYPMPO (sc-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphinan-2-yl)-5-methy-1-pyrroline N-oxide, O1-P1-C6-N1 torsion angle = 52.8°), with reactive oxygen species were examined by pulse radiolysis technique with 35 MeV electron beam and by electron spin resonance spectroscopy after (60)Co γ-ray irradiation. The spin-trapping reaction rate constants of G-CYPMPO toward the hydroxyl radical and the hydrated electron were estimated to be (4.2 ± 0.1) × 10(9) and (11.8 ± 0.2) × 10(9) M(-1)s(-1), respectively. Half-lives of the spin adducts, hydroxyl radical, and perhydroxyl radical adducted G-CYPMPO were estimated to be ～35 and ～90 min, respectively. A comparison of the results with earlier reports using different radical sources suggests that the purity of the solution and/or the radical generation technique may influence the stability of the spin adducts.     

Design of atomic mirror for silicon atoms

Abstract

Cook and Hill suggested that the gradient of an optical field can be used to reflect atoms. To reflect atoms, the repulsive dipole force is used, which comes from the interaction between the electric dipole moment of atoms and the evanescent field. The evanescent wave is generated when light is totally reflected internally at the interface of different refractive indices. Later, the way to enhance the evanescent wave with a thin dielectric waveguide has been reported. We designed the atomic mirror for silicon atoms, whose structure enhances the evanescent field that is used to repel silicon atoms. We also set up the equations of motion for silicon atoms and derive trajectories of the atoms reflected by the atomic mirror. Optical intensity, incident angle of the light, and effective detuning are described in terms of controlling the trajectory of the atom.     

Performance characteristics of external cavities to generate deep-ultraviolet coherent lights resonant to 3p3P14s3P0 cyclic transition of 28Si

Abstract

We developed a robust 252 nm single-mode coherent continuous-wave light source through two-stage highly efficient frequency conversion systems using external cavities. In the first stage, we obtained the second harmonics (SH) power of 630 mW from the LBO-installed external cavity by frequency doubling of a 746 nm Ti: sapphire laser with an efficiency of almost 50% [Y. Asakawa, H. Kumagai, K. Midorikawa, M. Obara, Opt. Commun. 217 (2003) 311.]. In the second stage, 252 nm light power was obtained by doubly resonant sum-frequency mixing of 373 nm light from the first-stage conversion system and 780 nm light from another Ti:sapphire laser. In the sum-frequency external cavity, the maximum 252 nm light power of over 150 mW is obtained, which is about three times larger than that obtained in our previous experiment.