In the past Koichi Matsumoto has collaborated on articles with Kazushige Tanaka and Masaki Matsui. One of their most recent publications is PaperThermodynamic analysis of magnetically active regenerator from 30 to 70 K with a Brayton-like cycle. Which was published in journal Cryogenics.

More information about Koichi Matsumoto research including statistics on their citations can be found on their Copernicus Academic profile page.

Koichi Matsumoto's Articles: (20)

PaperThermodynamic analysis of magnetically active regenerator from 30 to 70 K with a Brayton-like cycle

AbstractA magnetically active regenerator produces refrigeration without gas expansion because it makes use of the magnetocaloric effect. A magnetically active regenerator is equivalent to many cascading magnetic refrigerators. Analytical estimation of its performance is difficult owing to the complexity of the system. In the present paper, a model active regenerator with a Brayton-like operation cycle was analysed by numerical cycle simulation. DyAl2.2 sintered compound which has a Curie temperature of 50 K was adopted as the magnetic regenerator matrix in the temperature range below 70 K. From the analysis, the model active regenerator was shown to have the potential of attaining a lowest temperature of 30 K from 70 K. The optimum operating conditions giving maximum refrigeration capacity are discussed and thermal efficiency is estimated.

Regular paperEffect of thielocin A1β on bee venom phospholipase A2-induced edema in mouse paw

AbstractSeveral investigators have reported that inactivation of secretory phospholipase A2 purified from bee venom with p-bromophenacyl bromide, an irreversible inhibitor, before injection resulted in attenuation of the subsequent inflammatory reaction in the mouse paw edema model. Recently, thielocin A1β, a novel secretory phospholipase A2 inhibitor from fungi, was found to suppress histamine release from mast cells stimulated with secretory phospholipase A2. These observations led us to examine the effect of thielocin A1β against secetory phospholipase A2-induced paw edema. Thielocin A1β inhibited bee venom phospholipase A2 in a dose-dependent manner (IC50 = 1.4 μM). In addition, the inhibition of bee venom phospholipase A2 was noncompetitive (Ki = 0.57 μM) and reversible. Subplantar injection of bee venom phospholipase A2 produced a rapid but transient edematous response. Coinjection of thielocin A1β (1 μg/paw) with bee venom phospholipase A2 resulted in a 44.7 ± 4.6% reduction of edema formation. This anti-edema action was not enhanced by cyproheptadine (antihistamine/antiserotonin). These results suggest that thielocin A1β shows edema-reducing activity via inhibition of the phospholipase A2 activity which participates in histamine release by mast cells.

Letter to the editorCrystal growth of Eu-activated YVO4 phosphor by chemical transport method

AbstractSingle crystals of Eu-activated YVO4 phosphor were grown from powder by the chemical transport method. The transport was carried out from 1100°C (charge) to 950°C part in a silica ampoule using TeCl4 as a transporting agent. Fine crystals of 1.3 mm x 1.3 mm x 2.0 mm in dimensions, which were identified as YVO4 by EPMA and X-ray diffraction technique, were obtained after a one-week transport. They showed the red luminescence peculiar to Eu-activated YVO4 under excitation by UV.

Letter to the editorsChemical transport of SnS2 using sulfur as a transporting agent

AbstractThermodynamic evidence is presented for sulfur transport of SnS2 using SnO2 as a starting material.

Crystal growth of ZnO by vapor transport in a closed tube using Zn and ZnCl2 as transport agents

AbstractZinc oxide single crystals were grown by vapor transport in a closed tube. When only Zn or ZnCl2 was used as a transport agent, polycrystalline ZnO or small needle-like ZnO crystals were obtained. However, using both Zn and ZnCl2 as transport agents, prismatic and almost colorless single crystals of ZnO were obtained (e.g. 1.1 mm in diameter and 4.5 mm in length after a 100 h transport). Thermodynamic considerations of the system and evaluation of the transport rate suggested that a small amount of H2O adsorbed on the source material contributed to the transport reaction. Under UV excitation bright green luminescence was observed, where it was implied that for the ZnO crystals the deviation from stoichiometry was strongly related to the luminescence.

Crystal growth of ZnO by chemical transport using HgCl2 as a transport agent

AbstractCrystal growth of ZnO has been carried out by chemical transport in a closed tube using HgCl2 as a transport agent, and prismatic or needle-form crystals have been obtained. The transport rate has been discussed by comparing with theoretical calculations. The crystal grown were colorless and emitted no luminescence under UV excitation. The effect of excess Zn on these properties has also been discussed by comparing with the case of using NH4Cl as a transport agent.

Synthesis and characterization of 5-cyano-6-methyl-2,2'- bipyridine metal-complex dyes

AbstractNew 1:1 5-cyano-6-methyl-2,2'-bipyridine-metal (Co, Ni, Cu, and Zn) complex dyes have been synthesized in good yields. The metals do not significantly affect the wavelength of maximum absorption of the complexes; substituents at the 4-position showed remarkable bathochromic shifts in the following order: CHCHC6H4NMe2(p)>C6H4NMe2(p)>C6H5, ferrocenyl.

Association study: SLC6A18 gene and myocardial infarction

AbstractObjectiveSLC6A18 (solute carrier family 6, member 18) acts as a specific transporter for neurotransmitters, amino acids and osmolytes such as betaine, taurine and creatine. The aim of the present study was to investigate the relationship between the human SLC6A18 gene and myocardial infarction (MI) in a Japanese population.MethodsUsing 5 single nucleotide polymorphisms in the SLC6A18 gene (rs7728646, rs4975625, rs12522796, rs4975623 and rs7447815) we performed a case-control study based on each SNP and haplotype in 289 MI patients and 223 controls.ResultsLogistic regression analysis revealed that the frequency of the CC + CG genotype of rs7447815 was significantly higher in all patients and the male MI patients than in controls (P = 0.005, P = 0.036, respectively). The frequency of the T-C haplotype (rs7728646–rs7447815) was significantly higher for the MI patients when compared with controls (P = 0.037).ConclusionsThese results suggest that SLC6A18 or neighboring genes are associated with increased susceptibility to MI.

Numerical modeling on a reciprocating active magnetic regenerator refrigeration in room temperature

AbstractConsidering the unignorable factors in practice, a new time independent, 2-dimensional porous media model of room-temperature Active Magnetic Regenerative Refrigeration (AMRR) has been proposed. The 2-D model improved the existing 1-dimensional model by introducing the influence of heat transfer effect though the regenerator wall and conduction for y-axis inside the regenerator. This study compared the previous 1-D model with the 2-D model and concluded that the system can lose 22% of cooling capacity caused by air convection and the conduction loss in y can reach to 10% of cooling capacity. It is concluded that the new model will be useful to predict the performance of room AMRR for more practical conditions.

Quantitative nested real-time PCR assay for assessing the clinical course of tuberculous meningitis

AbstractAlthough the “gold standard” for diagnosis of tuberculous meningitis (TBM) is bacterial isolation of Mycobacterium tuberculosis (M. Tb), there are still several complex issues. Recently, in the diagnosis of TBM, the detection of M. Tb DNA in cerebrospinal fluid (CSF) samples using PCR has been widely performed as more rapid, sensitive, and specific diagnostic method. Based on Taq Man® PCR, the authors developed a novel technique of internally controlled quantitative nested real-time (QNRT) PCR assay that provided a prominent improvement in detection sensitivity and quantification. Total 43 CSF samples from 8 serial patients with suspected TBM were analyzed. The CSF samples were collected before and during standard anti-tuberculosis treatments (ATT). The QNRT-PCR assay revealed positive results for 24 out of 43 serial CSF samples (55.8%) collected during the treatment course of ATT. Moreover, the bacterial cell (BC) numbers of M. Tb analyzed by the QNRT-PCR assay decreased gradually, correlating with the improvements of the patient's clinical conditions. Since the QNRT-PCR assay provides the ability to calculate a numerical value for the initial BC numbers of M. Tb in CSF samples, this method is an extremely useful and advanced technique for use in assessing the clinical course of TBM.

Synthesis of β-mercuri ketones by the reaction of siloxycyclopropanes with mercuric acetate and their conversion to α-methylene ketones and γ-ketoesters☆

AbstractSiloxycyclopropanes were quantitatively converted to β-acetoxymercuri ketones by the reaction with mercuric acetate. Successive treatment with palladium chloride or palladium chloride/carbon monoxide gave α-methylene ketones or γ-ketoesters, respectively, in good yields.

Brief reportSerum interleukin-18 binding protein increases with behavior different from IL-18 in patients with diabetic nephropathy

AbstractWe investigated alterations between serum interleukin 18 (IL-18) and IL-18 binding protein (18BP) in T2DM patients. 18 BP began to increase after IL-18 increased and reached a threshold, in which case kidney dysfunction would have developed. These data indicate that 18BP might express glomerular dysfunction more closely than IL-18.

Magnetic entropy change of a rare earth garnet (Gd0.5Dy0.5)3(Ga0.875Fe0.125)5O12

AbstractThe working refrigerant in magnetic refrigerators has been Gd3Ga5O12 (GGG) in the temperature range from 1 to 15K. It has been shown that substitution of Ga for Fe in GGG can make entropy change large in high-temperature region. In order to increase the entropy change with small magnetic field, substitution of Gd for Dy is expected to be useful because of larger g-factor of Dy than Gd. The magnetization of (Gd0.5Dy0.5)3(Ga0.875Fe0.125)5O12 (GDGIG) was measured and the entropy change was calculated. This compound had larger entropy change with small magnetic field than that without Dy, though the absolute entropy change at low temperatures with large applied field was smaller due to the ground state doublet of Dy.

Magneto caloric effect in (DyxGd1−x)3Ga5O12 for adiabatic demagnetization refrigeration

AbstractGadolinium and dysprosium gallium garnet single crystals (DyxGd1−x)3Ga5O12(x=0,0.5 and 1) have been investigated for adiabatic demagnetization refrigeration used as magnetic materials between 0.5 and 5K. Specific heat measurement of (Dy0.5Gd0.5)3Ga5O12 showed a large and broad peak similar to that of Gd3Ga5O12 and it suggests that the geometrical frustration in Gd3Ga5O12 still remains in (Dy0.5Gd0.5)3Ga5O12. Magneto caloric effect of (Dy0.5Gd0.5)3Ga5O12 was about four times larger than that of Gd3Ga5O12 for the magnetic field of 1T between 0.5 and 5K. Therefore, the magnetic entropy change of Gd3Ga5O12 by the external magnetic fields could be enhanced by substituting Dy3+ ion for Gd3+ ion for the magnetic fields of <2T between 0.5 and 5K.

Density of liquid 3He in 8 T magnetic field

AbstractWe report a precise measurement of the density of liquid 3He in a 8 T field. Measurements performed at saturated vapour pressure between 30 and 300 mK show a field-induced increase of density. The relative change is about 1×10−5 in this temperature range. These results are in agreement with a calculation based on a Maxwell relation and the pressure dependence of the susceptibility.

Performance of absorption photometry microchip for blood hemoglobin measurement integrated with processing circuits and Si(1 1 0) 45° mirrors

AbstractIn this study, advantages of optical path extension in absorption photometry microchip for highly sensitive hemoglobin measurement have been demonstrated. Stability in repetitive measurement is evaluated with real blood samples. Long optical path (5 mm) is realized on the microchip for highly sensitive absorption photometry. Two 45° mirrors are fabricated in ‘Multi-layered smart-MEMS structure’ to form a long optical path. Different type of microchip with different optical path length (0.5 mm) without 45° mirrors was also fabricated for characteristic comparison. Both types of the microchip were evaluated with food color solution, and each characteristic were compared. As a result, effects of optical path extension are clearly shown as detectable lower limit improvement. Furthermore, no adverse effects due to utilization of 45° mirrors were observed. It has been demonstrated that optical path extension with 45° mirrors is very effective to realize highly sensitive measurement in the microchip. Stability in repetitive measurement of the microchip was evaluated with real blood sample for the first time. In repetitive blood sample measurement, slight degradation of photocurrent of photodiode, which corresponds to hemoglobin concentration in the microchip, was observed. It is considered that the degradation is caused by protein adhesion to the surface of the mirrors and the photodiode. However, influence of the degradation can be removed by measurement method of introducing reference solution and sample solution alternately into each channel. Furthermore, normal range of human hemoglobin has been covered with linear range of the microchip. A small coefficient of variation of 0.61% or less was obtained in the measured results. From these results, blood hemoglobin measurement with high sensitivity has been realized with stabilized characteristics in repetitive measurement.

Oral and Maxillofacial PathologyMucocele of the glands of Blandin-Nuhn: Clinical and histopathologic analysis of 26 cases*********

AbstractWe investigated the clinical and histopathologic features of 26 cases of mucocele of the glands of Blandin-Nuhn. There was a female predominance, and most patients were younger than 20 years. Fifteen patients first visited a medical doctor and 9 visited a dentist before being referred to our department. The average duration from the time the lesion was first noticed to the patient's visit was 3.6 months. All lesions were located on the ventral surface of the tongue. In 17 patients, mucoceles were seen at the tip of the tongue, whereas 9 lesions occurred more posteriorly. Lesions were situated at the midline in 19 patients and laterally in 7 patients. All lesions presented as an exophytic mass, often with a polypoid appearance. All mucoceles were histopathologically of the extravasation type, suggesting that trauma may represent a frequent initiating factor. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003;95:467-70)

Oral and Maxillofacial PathologyEpignathus combined with cleft palate, lobulated tongue, and lingual hamartoma: Report of a case

A case of epignathus combined with cleft palate, lobulated tongue, and lingual hamartoma is reported. A newborn female presented with a large skin-covered mass arising from the palate, cleft palate, and lobulated tongue with a soybean-sized lingual lesion. The palatal and lingual masses were removed on the 9th day after birth. A cystic lesion was also found on the nasal septum after removal of the palatal mass; this lesion was resected at its base. Glossoplasty was performed after excision of the lingual lesion. Histologically, the palatal mass was diagnosed as epignathus. The cystic lesion was suspected to be meningothelial tissues on the basis of hematoxylin-eosin (HE) and immunohistochemical staining: Vimentin and epithelial membrane antigen were positive, and factor VIII was negative. The mass of the tongue dorsum was diagnosed as hamartoma. No recurrence of epignathus or evidence of meningocele have been observed after 5 years of follow up.

Alimentary TractHigh-dose mesalazine treatment for ulcerative colitis patients who relapse under low-dose maintenance therapy

AbstractBackgroundMesalazine is often used to maintain remission in patients with ulcerative colitis.AimTo investigate if increasing the dose of mesalazine is safe and effective for patients with ulcerative colitis who relapse under low-dose maintenance therapy.MethodsNinety consecutive patients who relapsed during maintenance therapy with oral mesalazine at 1.5–2.25 g/day were included. All patients had mildly or moderately active ulcerative colitis at entry, and were treated with oral mesalazine at 4.0 g/day for the following 8 weeks. At entry and week 8, endoscopic examinations were carried out to assess the severity of endoscopic inflammation. The primary as well as the secondary endpoints were clinical and endoscopic improvements at week 8.ResultsNo patient experienced any serious side effect, and the treatment with 4.0 g/day mesalazine over the 8 week period was well tolerated by all patients. Fifty-nine patients (66%) achieved clinical improvement in stool frequency and/or rectal bleeding including 40 (44%) with clinical remission (normal stool frequency and no rectal bleeding). Forty-three patients (48%) showed endoscopic improvement including 25 (28%) with endoscopic remission.ConclusionsIncreasing the dose of mesalazine up to 4.0 g/day appeared to be safe and effective for patients who relapsed under low-dose, 1.5–2.25 g/day maintenance therapy.

Long-term clinical impact of early introduction of granulocyte and monocyte adsorptive apheresis in new onset, moderately active, extensive ulcerative colitis

AbstractBackground and aimsThe efficacy of granulocyte and monocyte adsorptive apheresis (GMA) for patients with a first episode of ulcerative colitis (UC) has been scarcely reported. This study was to see if the introduction of GMA at an early stage reduces corticosteroid administration and steroid dependency in the long term clinical course of UC.MethodsForty consecutive patients with moderately active symptoms as the first attack of UC were included. Twenty patients were treated with GMA, with or without corticosteroids (GMA group), and the other 20 were given corticosteroids without GMA (steroid group). All patients were monitored for 5 years. Relapses were treated in the same manner as the first attack in both groups. The total dose of steroid administered and the appearance of steroid-dependency were to be compared between the two groups.ResultsAll patients in both groups achieved clinical remission after the first attack. The mean number of relapses per patient was 2.8 in the GMA group and 2.9 in the steroid group (P = 0.86). During this study, 5 patients in the GMA group did not require corticosteroids. The mean dose of steroid administered during the 5 years was 2141 mg in the GMA group vs 5443 mg in the steroid group (P = 0.002). One patient in the GMA group and 7 in the steroid group were steroid-dependent at the end of the study (P = 0.048).ConclusionsIn patients with the first UC episode, GMA therapy at an early stage significantly reduces steroid administration and steroid-dependency in the long-term clinical course.

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