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The nitrogen deficiency in steels measured by atom probe tomography (APT) is considered to arise from the obscurement of singly charged dimer nitrogen ions (N2+) by the iron-dominant peak (56Fe2+) at 28 Da. To verify this by quantifying the amount of N2+ ions, γ′-Fe4N consisting of the 15N isotope was prepared on iron substrates by plasma nitriding using a nitrogen isotopic gas (15N2). Although considerable amounts of 15N2+ were observed at 30 Da without overlap with any iron peak, the observed nitrogen concentrations of γ′-Fe4N were clearly lower than the stoichiometric composition (19–20 at%), using both pulsed voltage and pulsed laser atom probes. The origin of the missing nitrogen, excluding nitrogen obscured by other ion species, was predicted to be the occurrence of neutral nitrogen or nitrogen gas molecules in field evaporation. The generation rate of iron nitride ions (FeN2+) for 15N was significantly lower than that for 14N in γ′-Fe4N, which affected the amount of the missing nitrogen. The isotope effect suggests that the isotopic ratio cannot always be determined from only one ion species among the multiple species observed in the APT analysis. We discuss the mechanism of the isotope effect in FeN2+ formation by field evaporation.
The carbon (C) ratios, namely the atomic ratios of C/(C + M), in nano-sized coherent MC precipitates (M = Ti, Nb) with the NaCl-type (B1) structure in ferritic steels, which had been isothermally aged at 580 °C, were investigated using atom probe tomography (APT). Considering the influences of the trajectory aberration, detection loss, and peak overlap, we determined the C ratios to be ~0.40 and ~0.45 for an equivalent volume diameter of 1.5–5 nm and 1–5 nm for the TiC and NbC precipitates, respectively, suggesting that there is a considerable fraction of C vacancies in both nano-sized precipitates. The apparent C ratios show significant scatter with decreasing particle size, while the apparent mean C ratios of very fine TiC particles, smaller than 1.5 nm, decreased with decreasing particle size. With the use of one of the latest APT instruments with a high detection efficiency, the scattering in the apparent C ratios was reduced because the counting statistics were improved; however, the artificial enrichment of C atoms to particular crystallographic directions of ferrite hindered the determination of the C ratio for very fine TiC particles smaller than 1.5 nm.
The quantitative analysis performance of carbon and nitrogen was investigated using stoichiometric θ-Fe3C (25 at% C) and γ′-Fe4N (~20 at% N) precipitates in pulsed voltage and pulsed laser atom probes. The dependencies of specimen temperature, pulse fraction, and laser pulse energy on the apparent concentrations of carbon and nitrogen were measured. Good coincidence with 25 at% carbon concentration in θ-Fe3C was obtained for the pulsed voltage atom probe by considering the mean number of carbon atoms per ion at 24 Da and the detection loss of iron, while better coincidence was obtained for the pulsed laser atom probe by considering only the mean number of carbon at 24 Da. On the other hand, a lack of nitrogen concentration in γ′-Fe4N was observed for the two atom probes. In particular, the pulsed laser atom probe showed a significant lack of nitrogen concentration. This implies that a large amount of 14N2+ was obscured by the main iron peak of 56Fe2+ at 28 Da in the mass-to-charge spectrum. Regarding preferential evaporation or retention, carbon in θ-Fe3C exhibited little of either, but nitrogen in γ′-Fe4N exhibited definite preferential retention. This result can be explained by the large difference in ionization energy between carbon and nitrogen.
We quantified an absolute imbalance of the medical risks and the support needs for children at each disaster-based hospital in Kanagawa immediately following the occurrence of a large earthquake by using the risk resource ratio (RRR) and need for medical resources (NMR).
The RRR and NMR of 33 disaster-based hospitals were estimated through dividing the estimated number of pediatric victims by the number of critically patients. We calculated the ratio of the NMR of each hospital.
The total number of pediatric victims in Kanagawa was estimated at 8,391. The total number of vacant beds for pediatric victims was 352. The median RRR and NMR of the total number of pediatric victims were 27 and 224. The median RRR and NMR of the number of critically ill pediatric patients were 27 and 12.
The absolute imbalance of the RRR and NMR for children in Kanagawa was quantified. This suggests that we might embark on preparedness strategies for children in advance. (Disaster Med Public Health Preparedness. 2018;13:672–676)
Diabetes mellitus is a metabolic disease spreading worldwide that has been reported to worsen the development and progression of other diseases (cancer, vascular diseases and dementia). To establish functional rice lines with anti-postprandial hyperglycaemic effects, we developed mutant rice lines, which lack one or two gene(s) related to starch synthesis, and evaluated their effects. Powder of mutant rice lines or other grains was loaded to rats fasted overnight (oral grain powder loading test). Incremental area under time-concentration curves (iAUC) were calculated with monitored blood glucose levels. Rice lines with anti-postprandial hyperglycaemic effects were separated by cluster analysis with calculated iAUC. A double mutant rice #4019 (starch synthase IIIa (ss3a)/branching enzyme IIb (be2b)), one of the screened mutant rice lines, was fed to Goto-Kakizaki (GK) rats, an animal model for type 2 diabetes, for 5 weeks. Plasma levels of C-peptide, a marker of pancreatic insulin secretion, were measured with ELISA. For in vitro study, a rat pancreatic cell line was cultured with a medium containing rat serum which was sampled from rats fed #4019 diet for 2 d. After 24-h of incubation, an insulin secretion test was performed. Through the oral rice powder loading test, seven rice lines were identified as antidiabetic rice lines. The intake of #4019 diet increased plasma C-peptide levels of GK rats. This result was also observed in vitro. In rat serum added to cell medium, ornithine was significantly increased by the intake of #4019. In conclusion, the mutant rice #4019 promoted pancreatic insulin secretion via elevation of serum ornithine levels.
The 2011 Fukushima Daiichi nuclear accident was the worst nuclear disaster since Chernobyl. The Daiichi workers faced multiple stressors (workplace trauma, victim experiences, and public criticism deriving from their company’s post-disaster management). Literatures suggest the importance of workplace interpersonal support (WIS) in enhancing psychological health among disaster workers. We sought to elucidate the role of their demographics, disaster-related experiences, and post-traumatic stress symptoms on perceived WIS.
We analyzed self-report questionnaires of 885 workers 2-3 months post-disaster. We used sociodemographic and disaster exposure-related variables and post-traumatic stress symptoms (measured by the Impact of Event Scale-Revised) as independent variables. We asked whether WIS from colleagues, supervisors, or subordinates was perceived as helpful, and used yes or no responses as a dependent variable. Logistic regression analyses were performed to assess correlates of WIS.
Of the participants, one-third (34.7%) reported WIS. WIS was associated with younger age (20-28 years [vs 49-], adjusted odds ratio [aOR]: 3.25, 95% CI: 1.99-5.32), supervisory work status (aOR: 2.30, 95% CI: 1.35-3.92), and discrimination or slur experience (aOR: 1.65, 95% CI: 1.08-2.53).
Educational programs focusing on WIS might be beneficial to promote psychological well-being among nuclear disaster workers, especially younger workers, supervisors, and workers with discrimination experiences. (Disaster Med Public Health Preparedness. 2018;12:460–463)
The objective was to clarify the outcomes of cardiac surgery in trisomy 18 patients.
Patients and methods
We analysed 34 consecutive trisomy 18 patients, of whom 21 were males, with cardiac complications. They were divided into patients who underwent cardiac surgery and those who were conservatively treated. We compared rates of survival and discharge alive between two groups.
The surgery group included nine patients, with six males, who underwent cardiac surgery – intracardiac repair in three patients, pulmonary arterial banding in five patients, and ligation of the ductus in one patient – at median age of 2.2 months, ranging from 0.5 to 9.8, and with median weight of 2.6 kilograms, ranging from 1.5 to 3.2. Cardiac surgery and pre-operative assisted ventilation were hazardous factors leading to death. In the surgery group, cumulative survival rates at 1 month, 6 months, 12 months, and 24 months were 63%, 38%, 25%, and 22%, respectively, compared with 51%, 26%, 9%, and 9% in the conservative group. There was a significant difference (p = 0.002). The cumulative rates of discharge alive at 1 month, 3 months, and 6 months were 0%, 12%, and 65% in the surgery group, which did not differ from the conservative group (p = 0.80).
Cardiac surgery contributed to increased survival rate but not the rate of discharge alive in trisomy 18 patients. Cardiac surgery could not prevent all the trisomy 18 patients from death. The indication of cardiac surgery should be carefully individualised to improve the quality of life in trisomy 18 patients and concerned surrounding people.
A wide variety of organic compounds have been found in carbonaceous chondrites and comets, which suggests that extraterrestrial organic compounds could have been an important source of the first terrestrial biosphere. In the Greenberg model, these organic compounds in the small bodies were originally formed in interstellar dusts (ISD) in dense clouds by the action of cosmic rays and ultraviolet light. We irradiated a frozen mixture of methanol, ammonia and water with high-energy heavy ions from an accelerator (“HIMAC” in NIRS, Japan) to simulate the action of cosmic rays in dense clouds. Racemic mixtures of amino acids were detected after hydrolysis of the irradiation products. A mixture of carbon monoxide, ammonia and water also gave such complex amino acid precursors with large molecular weights. When such amino acid precursors were irradiated with circular polarized UV light from a synchrotron, enantiomeric excesses were detected. The yield of amino acids was not largely changed between, before, and after CPL-irradiation. The present results suggest that the seed of homochirality of terrestrial amino acids were originally formed in interstellar space.
The ordered alloy phase of Ti3Al shows a rather wide solid solution range in aluminum and also in vanadium. Several Ti-Al-V ternary alloys have been prepared to investigate the alloy composition effect upon microstructure, crystallography, and mechanical characteristics. The materials containing 75, 70, and 65 at.% titanium, and 0 or 5 at.% vanadium were prepared by arc melting. Metallographic observation has revealed that the binary Ti-Al alloys contained somewhat coarse grains with about 100 μm grain diameter. In contrast to this, ternary alloys containing 5 at.% vanadium showed smaller grained microstructures with grain diameters around 15 μm. The grain size could not be adjusted to a unified value in the present study. X-ray diffraction study and microanalysis showed that the alloys contained single phase α2. Not every possible diffraction peak of the D019 ordered structure has been observed in the XRD patterns. The lattice parameters, a and c, were observed to decrease as the aluminum content increased and also when vanadium was added. Compression tests have been performed at various temperature ranging from an ambient temperature up to 1300K on rectangular parallelepiped specimens with 2mm×2mm×3mm dimensions. Alloys containing more aluminum showed higher strength, and vanadium addition enhanced the strength of the alloys. In some alloys deformability and strength are both enhanced by vanadium addition in some alloys. Temperature dependence of strength showed a little variation upon chemical compositions.
Two cases of linear IgA bullous dermatosis initially presenting as ulcerative lesions in the larynx and pharynx are reported. It was difficult to diagnose and treat the lesions, but they were finally diagnosed from the histopathological findings of accompanying skin lesion specimens. One of the patients required a tracheostomy due to increased airway stenosis by a laryngeal lesion. Despite general corticosteroid administration this could not be completely resolved, although partial opening of the glottis was observed, and the patient died of accidental tracheostomy tube complications during home care. Although there are no reports of this disease in the otolaryngological field, these rare diseases involving the skin and entire body should be considered in the differential diagnosis of laryngeal and pharyngeal ulcerative lesions, including airway stenosis. Furthermore, simple and safe procedures for relieving airway stenosis should be selected for rare and difficult-to-diagnose airway disease, prior to the final diagnosis.
We propose a new three-dimensional photonic crystal structure or drilled alternating-layer photonic crystal (DALPC), which can be fabricated by a combination of the deposition of alternating layers of dielectric films and one-time dry etching. Our band calculation predicts that the DALPC has a photonic band gap (PBG) in all directions. We fabricated a Si/SiO2DALPC by electron beam lithography, bias sputtering, and fluoride-gas electron cyclotron resonance etching. We measured the light transmission of the DALPC sample in both the in-plane and vertical directions. We observed a transmission minimum around the 1.4-μm-wavelength for all measured directions and TE/TM polarizations, which demonstrated a potential of the DALPC as a three-dimensional PBG material.
We propose a new three-dimensional photonic crystal structure or drilled alternating-layer photonic crystal (DALPC), which can be fabricated by a combination of the deposition of alternating layers of dielectric films and one-time dry etching. Our band calculation predicts that the DALPC has a photonic band gap (PBG) in all directions. We fabricated a Si/SiO2 DALPC by electron beam lithography, bias sputtering, and fluoride-gas electron cyclotron resonance etching. We measured the light transmission of the DALPC sample in both the in-plane and vertical directions. We observed a transmission minimum around the 1.4-µm-wavelength for all measured directions and TE/TM polarizations, which demonstrated a potential of the DALPC as a three-dimensional PBG material.
Anisortopic Si dry etching is usually carried out with chlorinated gases for electronic devices such as Si-LSIs. We had another look at Si dry etching with fluorinated gases in order to obtain an ideal air hole for two-dimensional Si photonic crystal. We simulated vertical Si etching, and showed the possibility that single crystal Si can be etched vertically with high selectivity to the etching mask using fluorinated gases. We investigated ECR etching with an SF6-CF4 mixture, and vertical Si etching was achieved at room temperature. High Si/Ni selectivity above 100 was also obtained. Two-dimensional Si photonic crystal with a photonic band gap between 1.25 and 1.51 μm was produced using SF6-CF4 ECR plasma and a thin Ni mask.
The defect formation during sublimation bulk crystal growth of silicon carbide (SiC) is discussed. SiC bulk crystals are produced by seeded sublimation growth (modified-Lely method), where SiC source powder sublimes and is recrystallized on a slightly cooled seed crystal at uncommonly high temperatures (≥2000°C). The crystals contain structural defects such as micropipes (hollow core dislocations), subgrain boundaries, stacking faults and glide dislocations in the basal plane. The type and density of the defects largely depend on the crystal growth direction, and many aspects are different between the growth parallel and perpendicular to the <0001> c-axis. Micropipes are characteristic defects to the c-axis growth, while a large number of stacking faults are introduced during growth perpendicular to the c-axis. We discuss the cause and mechanism of the defect formation
We have carried out structural analyses of highly conductive polyacetylene in order to elucidate the relationship between stucture and electrical properties. Sharp X-ray diffraction lines were observed for the heavily iodine-doped polyacetylene showing high conductivity, in contrast with the diffused diffractions of the conventional one. SEM observation reveals that granular structure of the new polyacetylene is composed of densely packed micro-fibrils. The result from the resonance Raman analysis indicates that the new cis-polyacetylene contains more longer conjugated segments than conventional polyacetylene. The relationship between the structure and conductivity is discussed, basing on the crystal structure and morphology observed.
Photochemical etching of Si and SiO2 using synchrotron radiation (SR) is carried out. The etching rate of SiO2 is much higher than those of poly-Si and single crystal Si. The etching rate of poly-Si increases as dopant concentration decreases. These material selectivities are quite different from those for plasma- or laser-excited etching. These new phenomena in SR-stimulated etching can be explained by a reaction model that contains reaction centers that are produced by both core and binding electronic excitation of Si and fluorinated Si in the surface layers. These centers are quenched by majority carriers.
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