Chemical Vapor-Deposited Amorphous Silicon Nitride

Chemical vapor-deposited amorphous Si_3N_4 (CVD-amorphous Si_3N_4) up to 4.2mm in thickness has been prepared from a gaseous mixture of NH_3 and H_2-carried SiCl_4 under various deposition conditions. The formation of the CVD-amorphous Si_3N_4 depended strongly on the deposition temperature, total gas pressure and gas flow rate. The CVD-amorphous Si_3N_4 prepared at 1100-1300℃ does not crystallize by heating at each deposition temperature. Their density and deposition rate are markedly dependent on deposition conditions and have maximum values of 3.00g/cm^3 (94% of the theoretical density of α-Si_3N_4) and 0.36mm/hr, respectively. The Vickers microhardness of the CVD-amorphous Si_3N_4 at room temperature varies between 2200 and 3200kg/mm^2 according to its deposition conditions. The hardness at 1300℃ is 1200～1300 kg/mm^2. The thermal conductivity was 0.010cal/cm/sec/℃ at 20℃ and 0.012cal/cm/sec/℃ at 1300℃. The thermal expansion coefficient at 20～1200℃ is 2.99±0.05/℃. The formation mechanism and the effect of gas flow patterns on the deposition rate of the CVD-amorphous Si_3N_4 are also discussed

Initial Results for Science Instruments Onboard EQUULEUS During the Cruising Phase Toward the Earth Moon Lagrange Point

EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) is a spacecraft to explore the cis-lunar region including the Earth-Moon Lagrange point L2 (EML2). The spacecraft is being jointly developed by JAXA, the University of Tokyo, and several other universities in Japan. After being launched into a lunar transfer orbit by NASA\u27s SLS (Space Launch System) Artemis-1 on November 16, 2022, the spacecraft successfully performed a first Delta-V and a trajectory correction maneuver. This enabled a precise lunar flyby and successful insertion into the orbit toward EML2. Although the size of EQUULEUS is only 6U CubeSat, the spacecraft carries three different science instruments. The spacecraft can effectively demonstrate science missions during and after the flight to EML2 by using these instruments; the plasmasphere observation around the Earth by PHOENIX, the space dust flux detection in the cis-lunar region by CLOTH, and the lunar impact flash (LIF) observation at the far side of the moon by DELPHINUS. All instruments have already completed its checkout. During the cruising phase, PHOENIX conducted Earth observations and successfully identified the Earth\u27s plasmashere. CLOTH has started regular standby operations. DELPHINUS obtained impressive images such as the far side of the Moon at lunar closest approach and long-period comet, Comet ZTF. This poster presents the details of these scientific missions and the initial checkout and observation results of the science instruments

Identification of the Occipito-Pontine Tract Using Diffusion-Tensor Fiber Tracking in Adult-Onset Adrenoleukodystrophy with Topographic Disorientation

X-linked adrenoleukodystrophy is a severe and progressive neurodegenerative disease caused by the peroxisomal transporter ATP-binding cassette, subfamily D, member 1 gene mutations. The defect of this gene product results in accumulation of very-long-chain fatty acids in organs and serum, central demyelination, and peripheral axonopathy. Although there are different magnetic resonance (MR) findings which reflect various phenotypes in adrenoleukodystrophy, some cases present with specific symmetrical occipital white-matter lesions. We describe a patient with adult-onset X-linked adrenoleukodystrophy with topographic disorientation, whose brain MR images revealed T2-signal hyperintensity along the occipito-pontine tract and lateral lemnisci, but not in the cortico-spinal tract in the brainstem. The occipito-pontine tract and lateral lemnisci were clearly detected using diffusion-tensor fiber tracking, suggesting that the topographic disorientation of this patient might be related to the occipito-pontine tract. MR tractography can effectively identify the occipito-pontine tract and may help to localize the fibers associated with clinical symptoms

Aortic Dissection in a Patient with Human Immunodeficiency Virus Infection That was Diagnosed at Autopsy : A Case Report.

A 43-year-old homosexual man was referred to our hospital for chest pain and loss of consciousness. He was hypertensive, and had an uncontrolled viral load. Serum creatinine revealed acute renal failure, and he died 3 days later. On autopsy, aortic dissection (TypeB) was found. No obvious inflammatory change, granulation, bacterial or fungal infection, or medionecrosis were seen at the dissection site. To our knowledge, this was the first case with HIV in whom aortic dissection was diagnosed at autopsy. Aortic dissection is a potential differential diagnosis even in young patients presenting with hypertension and chest pain

High-pressure and high-temperature synthesis of rhenium carbide using rhenium and nanoscale amorphous two-dimensional carbon nitride

Abstract: Both Re 2 C and Re 2 N are ultra incompressible and have a bulk modulus of about 400 GPa. These materials are synthesized under high pressure and high temperature. The synthesis pressures are about 10 GPa or below for Re 2 C and 20-30 GPa for Re 2 N. If the synthesis pressure of Re 2 N was about 10 GPa or below, a large volume high-pressure cell like a multi-anvil apparatus can be used to synthesize Re 2 N. To realize this, a proper solid nitrogen source is needed instead of liquid or gas nitrogen. We used a precursor of a mixture of rhenium and home-made nanoscale amorphous two-dimensional carbon nitride as a solid nitrogen source. Consequently, the synthesis reaction produced Re 2 C but not Re 2 N. We characterized the synthesized Re 2 C by various techniques including high-pressure x-ray diffraction (XRD). The bulk modulus B 0 of the synthesized Re 2 C under hydrostatic conditions was estimated to be 385.7 ± 18.0 GPa. This value is a little smaller than the previous data. When the pressure medium became non-hydrostatic, the peculiar compression behaviour occurred; the rate of broadening of XRD lines increased and the compression became negligible in the range of a few GPa. The reason for this peculiar behaviour is not known

An international comparative study of end-of-life vehicle (ELV) recycling systems

End-of-life vehicles (ELV) have become a global concern as automobiles have become popular worldwide. An international workshop was held to gather data and to discuss 3R policies and ELV recycling systems, their background and present situation, outcomes of related policies and programs, the framework of recycling and waste management, and case studies on related topics in several countries and regions, as well as the essential points of the comparison. Legislative ELV recycling systems are established in the EU, Japan, Korea, and China, while in the US, ELV recycling is managed under existing laws on environmental protection. Since automobile shredding residue (ASR) has a high calorific value and ash content, and includes heavy metals as well as a mass of unclassified fine particles, recycling ASR is considered highly difficult. Countries with a legislative ELV system commonly set a target for recovery rates, with many aiming for more than 95 % recovery. In order to reach this target, higher efficiency in ASR recovery is needed, in addition to material recycling of collectable components and metals. Environmentally friendly design was considered necessary at the planning and manufacturing stages, and the development of recycling systems and techniques in line with these changes are required for sound ELV management

Solar System Exploration Sciences by EQUULEUS on SLS EM-1 and Science Instruments Development Status

EQUULEUS is a spacecraft to explore the cislunar region including the Earth-Moon Lagrange point L2 (EML2) and will be launched by NASA’s SLS EM-1 rocket. Although the size of EQUULEUS is only 6U, the spacecraft carries three different science instruments. By using these instruments, the spacecraft will demonstrate three missions for solar system exploration science during and after the flight to EML2; imaging of the plasmasphere around the earth, observation of space dust flux in the cislunar region, and observation of lunar impact flashes at the far side of the moon. The developments and verifications of the flight models of these science instruments were completed by the end of 2018, and we started flight model integration and testing. This paper introduces the details of the scientific objectives, design results and development statuses of the instruments. In addition, results of the integration and pre-flight tests are also described

体外式腹部超音波が診断に有用であった十二指腸巨大Brunner 腺過形成の一例

Brunner 腺過形成は十二指腸腫瘍性病変で，大きさが40mm を超えるものは10% 未満と稀である．医学中央雑誌で「腹部超音波」「Brunner 腺過形成」のキーワードで検索すると，関連した報告はない．体外式超音波検査（US）が診断に有用であったBrunner 腺過形成の一例を報告する．症例は50歳代，女性．食欲不振，心窩部痛とタール便を主訴に近医受診．貧血を認め，出血源検索目的に行った上部消化管内視鏡検査（EGD）で胃内に約 45 mm の腫瘤性病変を認め精査目的に当院紹介となった．血液生化学検査ではHb 9.1 g/dl，MCV 89.1 fl，MCH 30.0 pg と正球性正色素性貧血を認め，BUN/CRE 比は43.1と上昇していた．当院でのEGD では十二指腸球部に内腔をほぼ閉塞する45×40 mm の腫瘤性病変を認めた．腫瘤表面の異型性は目立たないが，oozing bleeding を伴ったびらん形成を認めた．粘膜下腫瘍を疑い生検も行われたが確定診断には至らなかった．単純造影CT では十二指腸球部に 45 mm 程度の腫瘤性病変を認め，辺縁は遷延性に造影された．内部は低吸収域が認められ，嚢胞変性や壊死が疑われた．周囲臓器への浸潤や転移を示唆する所見は認めず，粘膜下腫瘍が疑われたが癌は否定できなかった．US では十二指腸球部後壁の第２層から第３層に存在する約55 mm の粘膜下腫瘍が認められた．固有筋層は正常で，内部は大半が多房性嚢胞からなり，嚢胞間に充実成分がみられた．血流は比較的豊富であるが血管径や形状に明らかな不整は認めなかった．以上より十二指腸Brunner 腺過形成が疑われた．外科的切除の方針となり，開腹で十二指腸粘膜下層剥離術を行った．術材の組織診断はBrunner 腺過形成で超音波診断と矛盾しない所見であった．十二指腸粘膜下腫瘍の鑑別には超音波内視鏡が有用であるが，大きな病変では全体の描出が困難などの欠点もある．一方でUS は内視鏡侵襲なく，比較的大きな病変も描出可能で，特に本症例の様に前庭部付近は良好な観察が期待できるため，上部消化管の精査に応用できる．Brunner’s gland hyperplasia is a duodenal neoplastic lesion, and its lesions measuring >40 mm in diameter are rare, accounting for <10% of cases. A search of the Ichushi (Japana Centra Revuo Medicina) database using the keywords “abdominal ultrasound” and “Brunner’s gland hyperplasia” yielded no relevant articles. Here we report a case of Brunner’s gland hyperplasia in which transabdominal ultrasonography (US) was useful for diagnosis. A female in her 50s presented to a local hospital complaining of anorexia, epigastric pain and tarry stool. She had anemia and esophagogastroduodenoscopy (EGD), which was performed to identify the source of bleeding, revealed a mass lesion measuring approximately 45 mm in diameter in the stomach. She was referred to our hospital for further examination. Blood biochemistry showed a hemoglobin (Hb) level of 9.1 g/dL, mean corpuscular volume (MCV) of 89.1 fL and mean corpuscular hemoglobin (MCH) of 30.0 pg, indicating normocytic normochromic anemia. The blood urea nitrogen (BUN)/creatinine (CRE) ratio was as high as 43.1. In our hospital, EGD revealed a 45×40 mm mass lesion almost obstructing the lumen in the duodenal bulb. Atypia of the mass surface was not prominent, but erosion with oozing bleeding was observed. A submucosal tumor was suspected, and biopsy was performed but did not lead to a definitive diagnosis. Plain contrast-enhanced computed tomography (CT) revealed a mass lesion with prolonged peripheral enhancement measuring approximately 45 mm in diameter in the duodenal bulb. There was a low-density area inside the mass, raising the suspicion of cystic degeneration and necrosis. There were no findings suggesting infiltration or metastasis to the surrounding organs, raising the suspicion of a submucosal tumor, but cancer could not be ruled out. US revealed a submucosal tumor measuring approximately 55 mm in diameter in the second to third layer of the posterior wall of the duodenal bulb. The muscularis propria was normal and mostly composed of multilocular cysts with solid components in the space between the cysts. Blood flow was relatively abundant, but there were no obvious irregularities in the diameter or shape of blood vessels. The above findings raised the suspicion of duodenal Brunner’s gland hyperplasia. It was decided to perform surgical resection, and she underwent open duodenal submucosal dissection. Histology of the surgical specimen revealed Brunner’s gland hyperplasia, cons istent with the ultrasonographic findings. Endoscopic ultrasonography is useful in the differential diagnosis of duodenal submucosal tumors, but also has disadvantages such that it is difficult to visualize the entire lesion, when the lesion is large. On the other hand, US can be applied to the detailed examination of the upper gastrointestinal tract, because there are no invasive endoscopic procedures and US can visualize relatively large lesions and, in particular, can be expected to satisfactory observe around the vestibule, like in the present case

Distribution and Niche Separation of Planktonic Microbial Communities in the Water Columns from the Surface to the Hadal Waters of the Japan Trench under the Eutrophic Ocean

The Japan Trench is located under the eutrophic Northwestern Pacific while the Mariana Trench that harbors the unique hadal planktonic biosphere is located under the oligotrophic Pacific. Water samples from the sea surface to just above the seafloor at a total of 11 stations including a trench axis station, were investigated several months after the Tohoku Earthquake in March 2011. High turbidity zones in deep waters were observed at most of the sampling stations. The small subunit (SSU) rRNA gene community structures in the hadal waters (water depths below 6000 m) at the trench axis station were distinct from those in the overlying meso-, bathy and abyssopelagic waters (water depths between 200 and 1000 m, 1000 and 4000 m and 4000 and 6000 m, respectively), although the SSU rRNA gene sequences suggested that potential heterotrophic bacteria dominated in all of the waters. Potential niche separation of nitrifiers, including ammonia-oxidizing archaea (AOA), was revealed by quantitative PCR analyses. It seems likely that Nitrosopumilus-like AOAs respond to a high flux of electron donors and dominate in several zones of water columns including shallow and very deep waters. This study highlights the effects of suspended organic matter, as induced by seafloor deformation, on microbial communities in deep waters and confirm the occurrence of the distinctive hadal biosphere in global trench environments hypothesized in the previous study.http://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr11-03/ehttp://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk11-e03/ehttp://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk11-e04_leg2/