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A 79-year-old man presented with subacute onset of dementia. Brain magnetic resonance imaging revealed leukoencephalopathy in the posterior lobes with presence of microbleeds. Although clinical manifestation suggested a diagnosis of leukoencephalopathy associated with cerebral amyloid angiopathy (CAA), the patient died of sudden rupture of an aneurysm of the thoracic aorta two months after the onset of dementia. Autopsy revealed pathological features of advanced-stage Alzheimer's disease. Immunohistochemistry for amyloid-β revealed CAA mainly affecting arteries but not capillaries. Klüver-Barrera staining revealed white matter edema predominantly in the occipital lobes without ischemic changes. Perivascular cuffing was found to be sparse, but there was no evidence of angiitis. Pathological findings suggest that leukoencephalopathy was caused by the disruption of the blood-brain barrier rather than ischemia. Because the present patient died before immunotherapy, his neuropathological findings could reflect the pathomechanism of the acute stage of leukoencephalopathy with CAA.

A 73-year-old women visited emergency department because of sudden right hemiplegia. She had a history of duodenum papilla cancer terminal stage and multiple liver metastasis. On admission, diffusion weighted images revealed high intensity area at left middle cerebral artery territory. In addition, 3D-TOF MRA depicted proximal part of the left internal carotid artery. We performed endovascular thrombectomy because low platelet count met contraindication of intravenous recombinant tissue plasminogen activator therapy. Although we could get partial recanalization of middle cerebral artery occlusion after thrombectomy, the patient eventually died due to multiple organ failure. Autopsy findings showed white thrombus on mitral valve and also left middle cerebral artery occluded by similar white thrombus without infective findings. The patient was finally diagnosed with nonbacterial thrombotic endocarditis due to white thrombus on the mitral valve. We should select appropriate mechanical thrombectomy devices with a case of cerebral infarction due to nonbacterial thrombotic endocarditis because its thrombus is often white thrombus and would be hard.

Multiple system atrophy (MSA) is pathologically characterized by the presence of fibrillar α-synuclein-immunoreactive inclusions in oligodendrocytes. Although the myelinating process of oligodendrocytes can be observed in adult human brains, little is known regarding the presence of α-synuclein pathology in immature oligodendrocytes and how their maturation and myelination are affected in MSA brains. Recently, breast carcinoma amplified sequence 1 (BCAS1) has been found to be specifically expressed in immature oligodendrocytes undergoing maturation and myelination. Here, we analyzed the altered dynamics of oligodendroglial maturation in both MSA brains and primary oligodendroglial cell cultures which were incubated with α-synuclein pre-formed fibrils. The numbers of BCAS1-expressing oligodendrocytes that displayed a matured morphology negatively correlated with the density of pathological inclusions in MSA brains but not with that in Parkinson’s disease and diffuse Lewy body disease. In addition, a portion of the BCAS1-expressing oligodendrocyte population showed cytoplasmic inclusions, which were labeled with antibodies against phosphorylated α-synuclein and cleaved caspase-9. Further in vitro examination indicated that the α-synuclein pre-formed fibrils induced cytoplasmic inclusions in the majority of BCAS1-expressing oligodendrocytes. In contrast, the majority of BCAS1-non-expressing mature oligodendrocytes did not develop inclusions on day 4 after maturation induction. Furthermore, exposure of α-synuclein pre-formed fibrils in the BCAS1-positive phase caused a reduction in oligodendroglial cell viability. Our results indicated that oligodendroglial maturation and myelination are impaired in the BCAS1-positive phase of MSA brains, which may lead to the insufficient replacement of defective oligodendrocytes. In vitro, the high susceptibility of BCAS1-expressing primary oligodendrocytes to the extracellular α-synuclein pre-formed fibrils suggests the involvement of insufficient oligodendroglial maturation in MSA disease progression and support the hypothesis that the BCAS1-positive oligodendrocyte lineage cells are prone to take up aggregated α-synuclein in vivo.

A 40-year-old man visited our department because of chest and back pain. He had a history of diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) 20 years ago. He received immunosuppressive therapy and had no relapses after that. On Admission, MRI showed tuberous hypertrophy of the spinal roots, intercostal nerves, and brachial and lumbar plexuses. The genetic analysis showed no mutations in any of Charcot-Marie-Tooth related genes. He was finally diagnosed with CIDP and administration of high dose intravenous methylprednisolone relieved his chest and back pain within a few days. We present a rare case of CIDP in which showed marked enlarged spinal roots in long clinical course and have a relapse with radicular pain without sensorimotor symptoms.

De novo variants (DNVs) cause many genetic diseases. When DNVs are examined in the whole coding regions of genes in next-generation sequencing analyses, pathogenic DNVs often cluster in a specific region. One such region is the last exon and the last 50 bp of the penultimate exon, where truncating DNVs cause escape from nonsense-mediated mRNA decay [NMD(−) region]. Such variants can have dominant-negative or gain-of-function effects. Here, we first developed a resource of rates of truncating DNVs in NMD(−) regions under the null model of DNVs. Utilizing this resource, we performed enrichment analysis of truncating DNVs in NMD(−) regions in 346 developmental and epileptic encephalopathy (DEE) trios. We observed statistically significant enrichment of truncating DNVs in semaphorin 6B (SEMA6B) (p value: 2.8 × 10(−8); exome-wide threshold: 2.5 × 10(−6)). The initial analysis of the 346 individuals and additional screening of 1,406 and 4,293 independent individuals affected by DEE and developmental disorders collectively identified four truncating DNVs in the SEMA6B NMD(−) region in five individuals who came from unrelated families (p value: 1.9 × 10(−13)) and consistently showed progressive myoclonic epilepsy. RNA analysis of lymphoblastoid cells established from an affected individual showed that the mutant allele escaped NMD, indicating stable production of the truncated protein. Importantly, heterozygous truncating variants in the NMD(+) region of SEMA6B are observed in general populations, and SEMA6B is most likely loss-of-function tolerant. Zebrafish expressing truncating variants in the NMD(−) region of SEMA6B orthologs displayed defective development of brain neurons and enhanced pentylenetetrazole-induced seizure behavior. In summary, we show that truncating DNVs in the final exon of SEMA6B cause progressive myoclonic epilepsy.

The susceptibility to neurological and psychiatric disorders reveals sexual dimorphism in the structure and function of human brains. Recent evidence has also demonstrated the sex-related differences in cellular components of the brain, including neurons, microglia, astrocytes, and endothelial cells. Oligodendrocyte precursor cells (OPCs) regulate the neuronal system in various ways and play crucial roles in brain homeostasis beyond their well-known role as a reservoir for mature oligodendrocytes. Although recent studies have shown regional diversities and heterogeneities of OPCs, sex-related differences in OPCs are largely unknown. Here, we revealed transcriptomic differences in OPCs isolated from male and female neonatal rat brains. Furthermore, we demonstrated sex-dependent differences in OPCs regarding proliferation, migration, differentiation, tolerance against ischemic stress, energy metabolism, and the ability to regulate the blood-brain barrier integrity.

Background Oligodendrocyte precursor cells ( OPC s) regulate neuronal, glial, and vascular systems in diverse ways and display phenotypic heterogeneity beyond their established role as a reservoir for mature oligodendrocytes. However, the detailed phenotypic changes of OPC s after cerebral ischemia remain largely unknown. Here, we aimed to investigate the roles of reactive OPC s in the ischemic brain. Methods and Results The behavior of OPC s was evaluated in a mouse model of ischemic stroke produced by transient middle cerebral artery occlusion in vivo. For in vitro experiments, the phenotypic change of OPC s after oxygen glucose derivation was examined using a primary rat OPC culture. Furthermore, the therapeutic potential of hypoxic OPC s was evaluated in a mouse model of middle cerebral artery occlusion in vivo. Perivascular OPC s in the cerebral cortex were increased alongside poststroke angiogenesis in a mouse model of middle cerebral artery occlusion. In vitro RNA ‐seq analysis revealed that primary cultured OPC s increased the gene expression of numerous pro‐angiogenic factors after oxygen glucose derivation. Hypoxic OPC s secreted a greater amount of pro‐angiogenic factors, such as vascular endothelial growth factor and angiopoietin‐1, compared with normoxic OPC s. Hypoxic OPC ‐derived conditioned media increased the viability and tube formation of endothelial cells. In vivo studies also demonstrated that 5 consecutive daily treatments with hypoxic OPC ‐conditioned media, beginning 2 days after middle cerebral artery occlusion, facilitated poststroke angiogenesis, alleviated infarct volume, and improved functional disabilities. Conclusions Following cerebral ischemia, the phenotype of OPC s in the cerebral cortex shifts from the parenchymal subtype to the perivascular subtype, which can promote angiogenesis. The optimal use of hypoxic OPC s secretome would provide a novel therapeutic option for stroke.

Oligodendrocytes (OLGs) support neuronal system and have crucial roles for brain homeostasis. As the renewal and regeneration of OLGs derived from oligodendrocyte precursor cells (OPCs) are inhibited by various pathological conditions, the restoration of impaired oligodendrogenesis is a therapeutic strategy for OLG-related diseases such as subcortical ischemic vascular dementia (SIVD). Fingolimod (FTY720), a drug for multiple sclerosis, is reported to elicit a cytoprotective effect on OPCs in vitro. However, the effects of fingolimod against ischemia-induced suppression of OPC differentiation remain unknown. Hence, the purpose of this study was to investigate the effectiveness of fingolimod against ischemia-induced suppression of oligodendrogenesis. For the in vitro experiments, primary rat cultured OPCs were incubated with a non-lethal concentration of CoCl2 to induce chemical hypoxic conditions and were treated with or without fingolimod-phosphate. We found that low concentration fingolimod-phosphate directly rescued ischemia-induced suppression of OPC differentiation via the phosphoinositide 3-kinase-Akt pathway. For the in vivo experiments, we used a mouse model of SIVD generated by bilateral common carotid artery stenosis. On day 28 after surgery, fingolimod ameliorated ischemia-induced demyelination and promoted oligodendrogenesis under prolonged cerebral hypoperfusion. The present study demonstrates that fingolimod can promote oligodendrogenesis under ischemic conditions and may be a therapeutic candidate for SIVD.

Variable Refrigerant Flow Rate (VRF) System is used as air-conditioning systems in small and medium-sized buildings in Japan. Traditionally, the two most common types of VRF systems are electric motor driven VRF Systems (EHP) and gas engine driven VRF Systems (GHP). However, in recent years’ society is increasingly demanding energy saving and the best energy mix. This requires an air-conditioning system that has energy flexibly depending on the application and situation. As a result, a hybrid air- conditioning system (called Hybrid VRF System) that satisfies theses need has been developed. The developed system can operate according to energy price and usage situations by connecting GHP and EHP with one refrigerant cycle. In recent years, a Hybrid VRF Systems have been used for small to medium-sized buildings. In this paper, the author evaluated the performance of an integrated Hybrid VRF System based on the energy evaluation method prescribed by Japanese law.

A 61-year-old woman developed hearing difficulties and became thirsty after experiencing cold symptoms. A neurological examination revealed a loss of odor sensation, facial palsy, dysphasia, and dysarthria. Vocal cord palsy was observed during pharyngoscopy. Brain magnetic resonance imaging (MRI) showed a thickened pituitary stalk and swelling of the pituitary gland, but no high signal intensity regions were seen in the posterior portion of the pituitary gland. Gadolinium-enhanced MRI demonstrated a thickened dura mater over the anterior cranial fossa. A biopsy specimen of the thickened dura mater showed fibrosis, granulomatous inflammation, and necrotic foci. Blood tests detected myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA). The patient's urine osmolarity was low even though she exhibited hypernatremia. We diagnosed her with hypertrophic pachymeningitis associated with MPO-ANCA and diabetes insipidus. The patient received two courses of 5-day high-dose intravenous methylprednisolone (1.0 g/day), and was subsequently administered oral prednisolone, which gradually relieved her symptoms. However, the patient's symptoms recurred despite the high-dose prednisolone treatment. It was difficult to control the patient's symptoms in this case with oral prednisolone monotherapy, but combined treatment with cyclosporine resulted in sustained remission. It is considered that patients with MPO-ANCA-positive hypertrophic pachymeningitis require combination therapy with prednisolone and immunosuppressive agents at an early stage.

Diseases due to mutations of polymerase γ (POLG) usually present with progressive external ophthalmoplegia. However, a few studies have been reported on POLG1 mutations with the mitochondrial neurogastrointestinal encephalomyopathy (MNGIE)-like phenotype. All cases with POLG1 mutations mimicking MNGIE have never shown leukoencephalopathy on brain magnetic resonance imaging (MRI) or demyelinating polyneuropathy. We present a 26-year-old male with gait disturbance, recurrent bowel obstruction, peripheral neuropathy, ophthalmoplegia or ptosis, which represented MNGIE phenotype. Though he displayed demyelinating peripheral neuropathy or leukoencephalopathy on brain MRI, genetic analysis revealed heterozygous mutation in POLG1 gene. We report for the first time two newly characteristics in our patient with heterozygous POLG1 mutations with the MNGIE-like phenotype: leukoencephalopathy and demyelinating polyneuropathy.

Background and Aim A major reason impeding the growth of endoscopic ultrasound (EUS) in Asia is the lack of training availability. We aimed to prospectively evaluate the effectiveness of a short-term structured EUS training program in improving the knowledge and skill of EUS among trainees. Methods The study was conducted in six workshops in six countries including Sri Lanka, Pakistan, Thailand, Vietnam, Singapore and Philippines, within a year. Trainees were evaluated using written and skill tests before and after completion of the training. Results Pre- and post-workshop written tests from a total of 62 trainees were analyzed. Compared with pre-training, the trainees improved significantly in the overall mean (± SD) scores after the training (66.0 ± 0.3% to 77.5 ± 0.2%, P

Background: Large-scale clinical trials have analyzed risk factors for any ischemic stroke in patients with atrial fibrillation (AF). However, the risk factors for cardioembolic stroke (CES), specifically, have not been reported. To clarify the risk factors for CES and clinically significant cardioembolic infarction, we examined the incidence of CES and larger infarct volume (IV) (> 30 mL) CES, employing the Fushimi AF Registry, a community-based prospective cohort of AF patients in the Fushimi ward, Kyoto, Japan. Methods: A total of 4,182 Fushimi AF patients were enrolled from March 2011 to December 2014. The risk factors for CES were evaluated using multivariate analysis. Results: Of 4,182 patients enrolled, 3,749 patients were observed for ≥1 year. During the follow-up period (mean duration, 979 ± 7.7 days), 91/3,749 patients experienced a CES (2.43%). Significant risk factors associated with CES were older age (odds ratio [OR], 1.31; 95% confidence interval [CI], 1.01–1.72; p = 0.046), low body weight (OR, 1.30; 95% CI, 1.03–1.65; p = 0.033), sustained AF (OR, 1.67; 95% CI, 1.05–2.71; p = 0.034), and previous stroke or transient ischemic attack (TIA) (OR, 1.94; 95% CI, 1.22–3.06; p = 0.004). Predictors of a large IV were chronic kidney disease (CKD) (OR, 2.08; 95% CI, 1.09–4.05; p = 0.027) and previous stroke/TIA (OR, 2.27; 95% CI, 1.19–4.24; p = 0.011). Conclusions: In this population-based cohort of Japanese patients with AF, in addition to previous stroke/TIA and older age, sustained AF and low body weight emerged as risk factors for CES, as opposed to any stroke, which may have a different risk profile. Patients with CKD or previous stroke/TIA who developed cardioembolic infarction exhibited more advanced severity. There is a need for direct oral anticoagulants that can be used safely in patients with comorbid AF and CKD.

Variable Refrigerant Flow Rate (VRF) System is used as air-conditioning systems in small and medium-sized buildings in Japan. Traditionally, the two most common types of VRF systems are electric motor driven VRF Systems (EHP) and gas engine driven VRF Systems (GHP). However, in recent years’ society is increasingly demanding energy saving and the best energy mix. This requires an air-conditioning system that has energy flexibly depending on the application and situation. As a result, a hybrid airconditioning system (called Hybrid VRF System) that satisfies theses need has been developed. The developed system can operate according to energy price and usage situations by connecting GHP and EHP with one refrigerant cycle. In recent years, a Hybrid VRF Systems have been used for small to mediumsized buildings. In this paper, the author evaluated the performance of an integrated Hybrid VRF System based on the energy evaluation method prescribed by Japanese law.

A major reason impeding the growth of endoscopic ultrasound (EUS) in Asia is the lack of training availability. We aimed to prospectively evaluate the effectiveness of a short-term structured EUS training program in improving the knowledge and skill of EUS among trainees.The study was conducted in six workshops in six countries including Sri Lanka, Pakistan, Thailand, Vietnam, Singapore and Philippines, within a year. Trainees were evaluated using written and skill tests before and after completion of the training.Pre- and post-workshop written tests from a total of 62 trainees were analyzed. Compared with pre-training, the trainees improved significantly in the overall mean (± SD) scores after the training (66.0 ± 0.3% to 77.5 ± 0.2%, P0.0001). Thirty-one trainees were randomly selected to undergo a skill test before and after the course. Compared with pre-training, the proportions of trainees who succeeded in locating each structure post-training were: celiac axis (36-80.5%), pancreatic body (51.5-80.5%), pancreatic body and tail (42-77.5%), splenic vein and artery (48.5-84%), left kidney (60-83%), and spleen (47-83%). Overall, there was a significant improvement in the proportion of trainees' successful localization of structures post-training compared to before training (P0.0001).Following a structured training program, trainees' knowledge and skills in EUS improved significantly. Structured training courses appear to be an effective way of imparting EUS knowledge and skills to aspiring endosonographers in the Asian region.

埋め立て処分場の延命, 負荷低減さらには有害物の無害化に対する有効な手段として, 都市ごみ焼却灰の溶融固化が注目され, 現在種々の技術開発が行われている。本研究では, 黒鉛発熱体を炉内に積層することによって大きな溶融表面積を有することを特徴とする誘導加熱方式の溶融炉を提案し, 灰処理能力0.8ton/日の実験設備を用いて, 都市ごみ焼却灰の溶融特性を検討した。総溶融時間31時間では, 93.9%の高スラグ化率が得られた。黒鉛発熱体の追加投入により, 温度および出滓量が制御でき連続運転が可能になる。黒鉛発熱体の消耗低減には, 灰中の酸化鉄濃度を下げること, 灰溶融炉内の02分圧を下げかっ運転温度を灰溶流点に近づけることが有効である。発熱体消耗低減対策後, 黒鉛消耗量は灰1tonあたり8.9kgであった。スラグ固化体からの重金属類の溶出は埋立基準以下である。

Best practice dictates that the performance metrics of an explosives-detecting sensor should be baselined against calibrated test samples under controlled conditions before testing proceeds to a rugged environment. This allows test parameters to be intelligently chosen for field testing, where the range of meaningful parameters would otherwise be too broad to allow efficient use of valuable field time. In support of internal field testing, the US Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD) has developed a technique which allows rapid generation of surfaces suitably dosed with explosive residues. The technique employs a commercial air spray gun to dispense controlled doses of dissolved analyte, requiring only relatively minor modifications. This approach was chosen with the vision of developing a method that would require minimal expense and effort to build. This monograph describes the process followed, and is compiled to serve as general guidance to sensor developers who wish to consider a similar approach.

Liquid phase diffusion welding of Ni-base superalloy (IN738LC) was studied. In this study, the surface of IN738LC was cleaned by Ar ion bombardment and an alloyed layer (Ni-B alloy, Ni-Cr-Si-B alloy) was deposited on the bonding surface by sputtering.In this report, the effect of Ar ion bombardment on melting temperature of alloyed layer formed on base metal, penetration of alloyed layer into base metal and weldability, and the effect of composition of alloyed layer on melting temperature of alloyed layer, penetration of alloyed layer into base metal and weldability were investigated.The main results indicated that : (1) The penetration was increased by cleaning with Ar ion bombardment.(2) Penetration of Ni-Cr-Si-B alloyed layer was larger than penetration of Ni-B alloyed layer and melting temperature range of Ni-Cr-Si-B alloyed layer was larger than melting temperature range of Ni-B alloyed layer.(3) Pressure of welding used Ni-Cr-Si-B alloyed layer was lower than pressure of welding used Ni-B alloyed layer. (4) Weldability with cleaning was better than weldability without cleaning (5) Tensile strength of welded joint was the same as tensile strength of base metal, but elongation and reduction of area were lower than elongation and reduction of area of base metal. But mechanical property was improved by diffusion heat treatment.

The superplasticity of rapidly solidified cast-type Ni-base superalloy melt-spun ribbons which have columnar grains was investigated. Melt-spun ribbons, about 80μm in thickness, were made by a twin roll process. Superplasticity was investigated in terms of peak flow stress, elongation of specimens, and strain rate sensitivity "m" by tensile tests carried out various strain rates at 1000°C and 1100°C. The maximum m was found to be about 0.70 and its maximum elongation was larger than 360%. (360% is limit of tensile test machine used in this study.) The microstructure of specimen after high temperature tensile test was observed, and still composed of columnar structure. From these results, it was found that fine columnar structure materials exhibited superplasticity as well as equi-axial grain structure in special conditions.

Oxidation behavior of Nb3Al has been studied in the temperature range from room temperature to 1500°C. It was revealed in this study that the oxide scale that formed at elevated temperatures was not protective against the propagation of the oxidation front. The products of oxidized Nb3Al alloys melted below 1500 °C, even though the melting point of Nb3Al is 1960°C. We expected that the addition of third elements would improve oxidation resistance because atomic sizes smaller than Nb and Al might reduce the solubility and diffusivity of oxygen in the alloy. The elements V, Mn, Fe, Mo, Ta, W and Re were added as the third element for the examination of oxidation resistance. The oxidation resistance tests were carried out by measuring weight gain during temperature elevation and during isothermal heating in air. It was concluded that the addition of Re or Mo improved the oxidation resistance for Nb3Al alloys.

Nb-Al and Nb-Al-X(X is Cr,Ti or Zr) ternary alloys ribbons, with compositions around the A15 (Nb3Al) structure, a candidate intermetallic as an advanced high temperature material, were rapidly solidified by an arc melt spin process. The rapid solidification structure of these tri-niobium aluminide alloys and the relationship between formed phases and compositions of ribbons are investigated.

In order to study possibilities of application of rapid solidification ribbons to an insert metal for solid phase diffusion welding of Ni-base supearlloy, welding was carried out by changing the welding pressure, time, and temperature using Ni-base superalloy ribbons (IN738LC, TMP-3, Rene 80, and Ni-Al-X three compositional alloys) produced by twin-roll rapid solidification process. The ribbon has almost similar composition to the base metal (Rene 80) and superplastic potential, then it needs relatively small flow stress on deformation. In this report, the influence of ribbon usage as an insert metal and carbon content in the ribbon on the joint strength were studied. The results are as follows, (1) The joint strength increases by using the ribbon for an insert metal compared to that without ribbons.(2) Carbide and oxide are formed on the welded interface during welding, resulting in decrease in welding strength.(3) The joint strength is increased and fractured position changes from the welded interface to the base metal, as the carbon content in the ribbon is decreased.

1. M. Berezovsky who took part in the west China expedition under the command of G. N. Potanin, 1884-1887, observed colour change on plumage of Japanese Crested Ibis near Hoi-cyan, Gan-su province, west China, 1884-1885.2. M. Berezovsky and V. Bianki (1891) described the result of Berezovski's observations as following items. a) All Japanese Crested Ibises observed in December have white plumages. b) In the end of January some of the birds have faint grey tint on the head and neck. c) In February some greyish birds are seen more often. By the end of this month some white ibises are met as exceptions. d) It is confirmed that the colour change takes place on the same birds, and that Nipponia nippon, var, sinensis described by A. A. David and M. E. Oustalet (1877) because of its grey plumage is nothing but Nipponia nippon itself with summer apparel. e) Spots where formation of black pigment takes place are found in the skin of head and neck. These are observed at the external surface of the skin, but particularly pronounced on the internal side. f) The change of colour begins in the end of January and is over by March, but during the whole time interval the behaviour of ibises is without any sign that would indicate beginning of the breeding period. g) Its plumage is white only in autumn and winter; they are grey in spring and summer. This fact is agreed by almost all data from China, Ussury-area and Japan which have descriptions of plumage colour and the time of observation or hunting. h) Nothing is known in the autumn change of apparel or moulting of the birds.3. This description did not call any attention to every ornithologist except Karl Deditius (1897) who mentioned "Das mitgebrachte Material beweist vollkommen, daβ Ibis sinensis ein Sommerkleid von Nipponia nippon ist, " and Ernst Hartert (1936) who referred to Berezovski's pronouncement, but did not accepted it.4. The author is grateful to Dr. Irina A. Dubrovo, Palaeontological Institute of the Academy of Sciences, U. S. S. R., for searching for this description and sending it to him and to Miss Kimiko Koshikawa for her help in translating old Russian of this description into Japanese.

In Ni-base superalloy Rene80 ribbon produced by a twin-roll rapid solidification process, the secondary dendrite arm spacing (SDAS) becomes smaller at the center of the thickness direction and the interfaces are observed between the initial and final solidification areas. By simulation of the solidification process of ribbon by the finite difference method, it is pointed out that the process is composed of three stages in the light of heat transfer. The distribution of secondary dendrite arm spacing calculated is in good agreement with the one measured.

The pseudoquaternary phase diagram of the Ga-In-As-Sb quaternary system has been determined experimentally. The liquidus data were obtained by DTA, and the solidus data were determined by the liquid phase epitaxial method. This phase diagram and the study of composition variations in the epitaxial layers indicate that the Ga-In-As-Sb quaternary system can form the lattice-matched GaxIn1-xAs1-ySby solid solutions on the GaSb and/or InAs binary compounds in the composition range of 0 ⩾ x < 0.3 and 0.6 < x ⩾ 1.0.