Benchmark experiment of large-angle scattering reaction cross section of iron at 14 MeV using two shadow bars – Comparison of experimental results with ENDF/B-VIII –

ABSTRACT

It is important to perform neutron transport simulations with accurate nuclear data in the neutronics design of a fusion reactor. However, absolute values of large-angle scattering cross sections vary among nuclear data libraries even for well-examined nuclide of iron. Benchmark experiments focusing on large-angle scattering cross sections were thus performed to confirm the correctness of nuclear data libraries. The series benchmark experiments were performed at a DT neutron source facility, OKTAVIAN of Osaka University, Japan, by the unique experimental system established by the authors’ group, which can extract only the contribution of large-angle scattering reactions. This system consists of two shadow bars, target plate (iron), and neutron detector (niobium). Two types of shadow bars were used and four irradiations were conducted for one experiment, so that contribution of room-return neutrons was effectively removed and only large-angle scattering neutrons were extracted from the measured four Nb reaction rates. The obtained experimental results were compared with calculations for five nuclear data libraries including JENDL-4.0, JEFF.-3.3, FENDL-3.1, ENDF/B- VII, and recently released ENDF/B-VIII. It was found from the comparison that ENDF/B-VIII showed the best result, though ENDF/B-VII showed overestimation and others are in large underestimation at 14 MeV.     

Theoretical estimation of dielectric loss of oxide glasses using nonequilibrium molecular dynamics simulations

To theoretically explore amorphous materials with a sufficiently low dielectric loss, which are essential for next-generation communication devices, the applicability of a nonequilibrium molecular dynamics simulation employing an external alternating electric field was examined using alkaline silicate glass models. In this method, the dielectric loss is directly evaluated as the phase shift of the dipole moment from the applied electric field. This method enabled us to evaluate the dielectric loss in a wide frequency range from 1 GHz to 10 THz. It was observed that the dielectric loss reaches its maximum at a few THz. The simulation method was found to qualitatively reproduce the effects of alkaline content and alkaline type on the dielectric loss. Furthermore, it reasonably reproduced the effect of mixed alkalines on the dielectric loss, which was observed in our experiments on sodium and/or potassium silicate glasses. Alkaline mixing was thus found to reduce the dielectric loss.     

Direct Injection of CRISPR/Cas9-Related mRNA into Cytoplasm of Parthenogenetically Activated Porcine Oocytes Causes Frequent Mosaicism for Indel Mutations

Some reports demonstrated successful genome editing in pigs by one-step zygote microinjection of mRNA of CRISPR/Cas9-related components. Given the relatively long gestation periods and the high cost of housing, the establishment of a single blastocyst-based assay for rapid optimization of the above system is required. As a proof-of-concept, we attempted to disrupt a gene (GGTA1) encoding the α-1,3-galactosyltransferase that synthesizes the α-Gal epitope using parthenogenetically activated porcine oocytes. The lack of α-Gal epitope expression can be monitored by staining with fluorescently labeled isolectin BS-I-B₄ (IB4), which binds specifically to the α-Gal epitope. When oocytes were injected with guide RNA specific to GGTA1 together with enhanced green fluorescent protein (EGFP) and human Cas9 mRNAs, 65% (24/37) of the developing blastocysts exhibited green fluorescence, although almost all (96%, 23/24) showed a mosaic fluorescent pattern. Staining with IB4 revealed that the green fluorescent area often had a reduced binding activity to IB4. Of the 16 samples tested, six (five fluorescent and one non-fluorescent blastocysts) had indel mutations, suggesting a correlation between EGFP expression and mutation induction. Furthermore, it is suggested that zygote microinjection of mRNAs might lead to the production of piglets with cells harboring various mutation types.     

Photocatalytic Property and Electronic Structure of Lanthanide-based Oxysulfides

Lanthanide-based oxysulfides and sulfide, LnTaO_3.5S_0.5, Ln₁₀OS₁₄ (Ln = La, Pr, Nd, Sm) and La₄In₅S₁₃, were successively synthesized by sulfurization in a flowing H₂S. The sulfurization decreased the band-gap energies from >4 eV to <3eV, because of the formation of occupied S3p orbitals on the top of valence band. In accordance with the small band gap, the H₂ evolution from a 0.01 M Na₂S and 0.01 M Na₂SO₃ solution system was observed under irradiation of light up to >500 nm. The rate of H₂ evolution under light irradiation of >500 nm increased in the order of Ni/LaTaO_3.5S_0.5 < Ru/La₁₀OS₁₄ < Pt/La₄In₅S₁₃.     

The significance of urinary N-acetyl-beta-D-glucosaminidase for predicting early stage diabetic nephropathy

We studied urinary N-acetyl-beta-D-glucosaminidase (NAG) in the early stage of diabetic nephropathy in 27 non-insulin-dependent diabetes mellitus (NIDDM) patients with a microalbumin level below 20 mg on 24-hour urine sample. Microalbumin and NAG excretion were measured in 24-hour urine samples collected on three separate occasions within seven days of admission. Creatinine clearance was determined simultaneously. There was a significant negative correlation between the creatinine clearance and 24-hour urinary NAG (r = -0.38, p < 0.05). Elevation of urinary NAG may indicate decreased renal function during early stage NIDDM nephropathy.     

Formation and Characterization of Ce3ZrO8 Prepared by the Hydrazine Method

A compound denoted as (Ce_0.75Zr_0.25)O₂ (Ce, ZrO₈) is formed near room temperature from cerium and zirconium nitrates using hydrazine monohydrate. It has a cubic unit cell with a = 0.5342 nm. Characterization of powders heated to various temperatures at 10°C/min demonstrates that the specific surface area does not decrease below 20 mVg until >1000°C.     

BONDING OF CERAMICS TO METALS WITH ACTIVATED COATING LAYERS MADE BY PLASMA SPRAYING

Bonding of ceramics to metals was carried out by using thermal sprayed coatings as interlayer materials. This bonding method is referred as the thermal spray bonding. In the present study, Si₃N₄ and Al₂O₃ ceramics were bonded to SS41 mild steel using activated Ti-Cu multilayer coatings plasma-sprayed on the steel in a low pressure atmosphere. The bondability was estimated by SEM/EDX analysis and shear tests of the joints. The results were compared to those obtained using Ti-Cu multilayer foils as interlayers. When using Ti-Cu foils as interlayers, brittle Fe-Ti compound layers were formed in the joint area after long time heating at a bonding temperature of 900°C, which deteriorated the joint strength. In contrast with the activated interlayers made by plasma spraying, the Ti-Cu eutectic reaction took place uniformly at the joint immediately after heating to the bonding temperature. This improved the bondabilrty, and the resultant joints exhibited shear strengths of about 180 MPa.     

Comparative clinical study of adjuvant postoperative chemotherapy (5-FU, Tegafur, 5-FU + MMC) in curatively resected cases of gastric cancer. Study Group on 5-FU Oral Adjuvant Chemotherapy in Gastric Cancer

A multi-center collaborative study was conducted in curatively resected gastric cancer patients at Stages II and III to compare oral 5-FU (Group A), oral Tegafur (Group B) and i.v. MMC + oral 5-FU (Group C). From May 1982 to April 1985, 1,012 cases were enrolled at 55 institutions. Some 138 (13.8%) were excluded, and 874 were analyzable. In the analysis of background factors, Group B had more cases with tumor of large diameter and advanced Stage. Adverse effects were relatively mild in all groups, and there was no problem in drug tolerance. Five-year survival rate was 67.6%, 62.4% and 68.6% in Groups A, B and C, respectively, reflecting no significant difference among them. It was 85.0%, 83.0% and 81.1% in Stage II and 52.5%, 51.0% and 59.0% in Stage III of Groups A, B and C, respectively. No significant difference was found, but Stage III of Group C showed a slightly higher survival rate. Supportive clinical study will be required to assess the usefulness of MMC as an introduction therapy. We found no difference in efficacy between 5-FU and Tegafur as maintenance therapy. The life-prolongation effect of fluoropyrimidines in comparison with surgery alone should be studied separately.     

Crosslinking of amidated polybutadiene with resole. I

Various liquid polybutadiene derivatives were examined as modifiers to improve the brittleness of phenolic resins. Amidated polybutadienes obtained from a maleinated polybutadiene and ammonia had the highest curing tendency when they were reacted with resole under mild conditions. The cured resins were homogeneous and the brittleness of the phenolic resins was remarkably improved. Crosslinking efficiency was closely related to the succinamic acid group of the amidated polybutadiene. Thermal behavior of the succinamic acid group was also related to the effects of curing temperature and curing time on crosslinking. From these observations, cross-condensation between the succinamic acid group of an amidated polybutadiene and resole seemed to have occurred to a great extent than the self-condensation of resole itself and oxidative crosslinking of the amidated polybutadiene.     

Eight-channel flat spectral response arrayed-waveguide multiplexer with asymmetrical Mach-Zehnder filters

An eight-channel flat spectral response arrayed-waveguide grating (AWG) multiplexer with asymmetrical Mach-Zehnder filters has been fabricated on the planar lightwave circuit (PLC). The monotonic spectral loss characteristics of AWG have been canceled by the opposite spectral response in the asymmetric MZ filter. The 1.5 dB bandwidth of 141 GHz and 3 dB bandwidth of 159 GHz are obtained for the 200 GHz channel spacing. The 1.5 dB bandwidth becomes 1.8 times wider than that of the conventional AWG. Crosstalks to neighboring and all other channels are less than -24 dB and the on-chip insertion losses range from 7.0 to 7.4 dB, respectively.