Differential interference contrast microscopy for cells using hard x-ray holography.

We propose a differential interference contrast method for cells using hard x-ray Gabor holography and knife-edge filtering in the spatial frequency domain, without relying on beam shearing. A phase object is holographically recorded and reconstructed by computer. Interference between the wavefronts of zeroth order weighted by ejπ/2 in the positive frequency region produces a dark image. Similarly, interference between the wavefronts of the zeroth order weighted by ej3π/2 in the negative frequency region produces a bright image. By adding these two intensity distributions, good quality phase-contrast images of 8-µm-diameter polystyrene beads and human HeLa cells were obtained.

Fast Heating of Imploded Core with Counterbeam Configuration.

A tailored-pulse-imploded core with a diameter of 70 µm is flashed by counterirradiating 110 fs, 7 TW laser pulses. Photon emission (>40 eV) from the core exceeds the emission from the imploded core by 6 times, even though the heating pulse energies are only one seventh of the implosion energy. The coupling efficiency from the heating laser to the core using counterirradiation is 14% from the enhancement of photon emission. Neutrons are also produced by counterpropagating fast deuterons accelerated by the photon pressure of the heating pulses. A collisional two-dimensional particle-in-cell simulation reveals that the collisionless two counterpropagating fast-electron currents induce mega-Gauss magnetic filaments in the center of the core due to the Weibel instability. The counterpropagating fast-electron currents are absolutely unstable and independent of the core density and resistivity. Fast electrons with energy below a few MeV are trapped by these filaments in the core region, inducing an additional coupling. This might lead to the observed bright photon emissions.

Direct heating of a laser-imploded core by ultraintense laser-driven ions.

A novel direct core heating fusion process is introduced, in which a preimploded core is predominantly heated by energetic ions driven by LFEX, an extremely energetic ultrashort pulse laser. Consequently, we have observed the D(d,n)^{3}He-reacted neutrons (DD beam-fusion neutrons) with the yield of 5×10^{8} n/4π sr. Examination of the beam-fusion neutrons verified that the ions directly collide with the core plasma. While the hot electrons heat the whole core volume, the energetic ions deposit their energies locally in the core, forming hot spots for fuel ignition. As evidenced in the spectrum, the process simultaneously excited thermal neutrons with the yield of 6×10^{7} n/4π sr, raising the local core temperature from 0.8 to 1.8 keV. A one-dimensional hydrocode STAR 1D explains the shell implosion dynamics including the beam fusion and thermal fusion initiated by fast deuterons and carbon ions. A two-dimensional collisional particle-in-cell code predicts the core heating due to resistive processes driven by hot electrons, and also the generation of fast ions, which could be an additional heating source when they reach the core. Since the core density is limited to 2 g/cm^{3} in the current experiment, neither hot electrons nor fast ions can efficiently deposit their energy and the neutron yield remains low. In future work, we will achieve the higher core density (>10 g/cm^{3}); then hot electrons could contribute more to the core heating via drag heating. Together with hot electrons, the ion contribution to fast ignition is indispensable for realizing high-gain fusion. By virtue of its core heating and ignition, the proposed scheme can potentially achieve high gain fusion.

Fusion using fast heating of a compactly imploded CD core.

A compact fast core heating experiment is described. A 4-J 0.4-ns output of a laser-diode-pumped high-repetition laser HAMA is divided into four beams, two of which counterilluminate double-deuterated polystyrene foils separated by 100 µm for implosion. The remaining two beams, compressed to 110 fs for fast heating, illuminate the same paths. Hot electrons produced by the heating pulses heat the imploded core, emitting x-ray radiations >20 eV and yielding some 10(3) thermal neutrons.

Association of polymorphism in the promoter region of the apolipoprotein E gene with diastolic blood pressure in normotensive Japanese.

The epsilon4 allele of apolipoprotein E (APOE) is reported to be a genetic risk factor of atherosclerosis through hyperlipidemia and late-onset Alzheimer's dementia. A recent report showed that a genetic variant (A -491T) in the promoter region of the APOE gene increases the risk of Alzheimer's disease. In the present study, we examined whether these APOE polymorphisms were genetically involved in essential hypertension. Japanese hypertensives (n=180) with a family history of hypertension and normotensive controls (n=195, sex and age matched with hypertensives) were recruited from the outpatients of Osaka University Hospital, and an informed consent to participate in the study was obtained from each person. APOE polymorphisms were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The frequencies of the A -491 allele in hypertensives and normotensives were 0.98 and 0.97, respectively, and the TT/-491 genotype was not found in either group. No significant differences between hypertensives and normotensives were observed in allele frequencies in either APOE polymorphism; however, the mean diastolic blood pressure in normotensive subjects with AA/-491 was significantly higher than in the subjects with AT/-491 (p < 0.01). These results suggest that the presence of the APOE promoter polymorphism is not a major risk factor for hypertension but that it does have some minor effect on basal blood pressure variation.

A high expression of heme oxygenase-1 in the liver of LEC rats at the stage of hepatoma: the possible implication of induction in uninvolved tissue.

We have examined changes in the expression of heme oxygenase-1 (HO-1), an inducible isoform and HO-2, a constitutive isoform, in the liver of Long-Evans with a Cinnamon-like color (LEC) rat, a mutant strain which spontaneously develops acute hepatitis and hepatoma. HO-1 expression was highly enhanced in the LEC rat livers with jaundice, and then decreased slightly, but overall remained at a higher level than in the Long-Evans with Agouti color (LEA) control rats, as judged by Northern blotting analysis of the whole liver extract. The high expression of HO-1 in the LEC rat liver was, however, not due to the actual cancer lesion but, rather, due to the surrounding uninvolved tissues including hepatocytes. Immunohistochemical analysis also supported this conclusion. Among normal tissues, the expression of HO-1 but not HO-2 was high in only the spleen of both LEC and LEA rats. The high expression observed in the stage of acute hepatitis and hepatoma stages in the LEC rat is probably due to the oxidative stress caused by the accumulation of free copper and free iron levels which has been reported earlier by our group (Suzuki et al., Carcinogenesis, 1993, 14, 1881-1884 and Koizumi et al., Free Radical Research, in press) as well as by free heme levels. The inflammatory cytokines produced by the surrounding tissue at the hepatoma stage would also be expected to play a role in the induction mechanism. The physiological relevance of HO-1 induction might be an adaptive response to oxidative stress and vasodilatory effect of carbon monoxide on sinusoidal circulation.