135 research outputs found

    Specific heat and magnetization of a ZrB12 single crystal: characterization of a type II/1 superconductor

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    We measured the specific heat, the magnetization, and the magnetoresistance of a single crystal of ZrB12, which is superconducting below Tc ~ 6 K. The specific heat in zero field shows a BCS-type superconducting transition. The normal- to superconducting-state transition changes from first order (with a latent heat) to second order (without latent heat) with increasing magnetic field, indicating that the pure compound is a low-kappa, type-II/1 superconductor in the classification of Auer and Ullmaier [J. Auer and H. Ullmaier, Phys. Rev.B 7, 136 (1973)]. This behavior is confirmed by magnetization measurements. The H-T phase diagram based on specific-heat and magnetization data yields Hc2(0) =550 G for the bulk upper critical field, whereas the critical field defined by vanishing resistance is a surface critical field Hc3(0) ~ 1000 G.Comment: 17 pages, 8 figures, submitted to PR

    Modulated-bath AC calorimetry using modified commercial Peltier-elements

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    We developed a new type of AC microcalorimeter based on a modulated-bath technique for measuring the specific heat of small microgram samples in the temperature range from 30-300 K, and tested it in magnetic fields up to 14 T. The device is built from a modified commercial Peltier element. The temperature of its top plate can be modulated periodically by Peltier effect, so that the oscillation is symmetrical about the temperature of the main bath. This avoids the problem of DC offsets which plagues conventional AC calorimeters. The sample is attached to a thin thermocouple cross, acting as a weak thermal link to a platform. The absence of a heater reduces the background heat capacity ('addenda') to a minimum. As an illustrative example of the performance of our device, the specific heat in fields up to 14 T of a small single crystal of the high-temperature superconductor Bi2.12Sr1.71Ca1.22Cu1.95Oy has been determined.Comment: revised version accepted for publication in Review of Scientific instrument

    Effect of temperature on achene germination in five Mutisieae understory herbaceous species(Asteraceae)

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    We measured the final germination rates of achenes, the number of days needed to accomplish 50% of the final germination(T50), and mortalities under various temperatures in the range 5 to 25℃for five understory peren-nial herbs(four species with large achenes of ca. 10 mg weight : Pertya robusta, P . triloba, P . rigidula and Ain-sliaea acerifolia var. subapoda, and one species with small achenes(1mg): A. apiculata)to investigate variation of these traits. Achenes were collected in Ogawa and Mito in Ibaraki Prefecture, and in Iwakuni in Fukui Prefec-ture. T50 ranged from 35 to 76 days at 5℃and became shorter with increasing temperature. The final germina-tion rates of most samples were over 95%. Ainsliaea acerifolia had the longest T50(76 days)and the lowest final germination rate(86.1%)at 5℃, showing a dormant ability to some extent. Moreover, A. apiculata possessing small achenes showed a lower final germination rate(83%)at 25℃, and dormancy at higher temperatures. Fun-gal attack was thought to cause the death of achenes during the germination period, and mortalities increased with increasing temperature. However, there were no significant differences in final germination rates and T50s between two populations of P . robusta from Ogawa and Mito, though the Ogawa population had a higher mor-tality than the Mito population(27% vs. 18% at 25℃). Mortalities were higher in P . triloba and P . rigidula than in the other species. There were intra- and interspecific variations of temperature dependency of achene mortal-ity during germination, and these variations may be one of the factors limiting the distribution of each species

    Influence of Hepatectomy on Body Temperature Change in Rats

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    Abdominal surgery, especially liver resection and transplantation, increases body temperature during and after surgery, but the precise mechanism (s) underlying this effect are not well understood. The present study thus sought to investigate this phenomenon using an experimental rat model. Specific pathogen-free male Sprague-Dawley rats, 5 weeks of age, underwent a two-thirds partial hepatectomy (PH), one-third splenectomy, or left kidney resection, and then rectal temperature was measured for 5 consecutive days after surgery. Rectal temperature increased in PH rats to a peak on day 4, but no change in temperature was detected after splenectomy and kidney resection. In the second part of the study, we examined the influence of gadolinium chloride and interleukin-1β monoclonal antibody (IL-1β mAb) on the increase in rectal temperature following PH. Treatment of rats with 20mg/kg gadolinium chrolide or 200µg IL-1β mAb inhibited the PH-induced increase in rectal temperature and decrease in IL-1β and prostaglandin E2, which act as pyrogens to change the thermoregulatory set point in the hypothalamus. These results suggest that abdominal surgery, especially liver resection, caused an increase in endogenous pyrogen production that results in increased body temperature

    Rice Mutants Lacking Starch Synthase I or Branching Enzyme IIb Activity Altered Starch Biosynthetic Protein Complexes

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    Amylopectin, the major component of starch, is synthesized by synergistic activity of multiple isozymes of starch synthases (SSs) and branching enzymes (BEs). The frequency and length of amylopectin branches determine the functionality of starch. In the rice endosperm, BEIIb generates short side chains of amylopectin and SSI elongates those branches, which can be further elongated by SSIIa. Absence of these enzymes greatly affects amylopectin structure. SSI, SSIIa, and BEIIb associate with each other and with other starch biosynthetic enzymes although SSIIa is low activity in japonica rice. The aim of the current study was to understand how the activity of starch biosynthetic enzyme complexes is compensated in the absence of SSI or BEIIb, and whether the compensatory effects are different in the absence of BEIIb or in the presence of inactive BEIIb. Interactions between starch biosynthetic enzymes were analyzed using one ss1 null mutant and two be2b japonica rice mutants (a mutant producing inactive BEIIb and a mutant that did not produce BEIIb). Soluble proteins extracted from the developing rice seeds were separated by gel filtration chromatography. In the absence of BEIIb activity, BEIIa was eluted in a broad molecular weight range (60–700 kDa). BEIIa in the wild-type was eluted with a mass below 300 kDa. Further, majority of inactive BEIIb co-eluted with SSI, SSIIa, and BEI, in a mass fraction over 700 kDa, whereas only small amounts of these isozymes were found in the wild-type. Compared with the be2b lines, the ss1 mutant showed subtle differences in protein profiles, but the amounts of SSIIa, SSIVb, and BEI in the over-700–kDa fraction were elevated. Immunoprecipitation revealed reduced association of SSIIa and BEIIb in the ss1 mutant, while the association of BEIIb with SSI, SSIIa, SSIVb, BEI, and BEIIa were more pronounced in the be2b mutant that produced inactive BEIIb enzyme. Mass spectrometry and western blotting revealed that SSI, SSIIa, SSIIIa, BEI, BEIIa, starch phosphorylase 1, and pullulanase were bound to the starch granules in the be2b mutants, but not in the wild-type and ss1 mutant. These results will aid the understanding of the mechanism of amylopectin biosynthesis

    Importance of feeding status evaluation in older patients undergoing hemodialysis

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    Older hospitalized patients undergoing hemodialysis are increasingly experiencing malnutrition caused by dysphagia. However, only a few studies have focused on this problem. We used the Kuchikara Taberu Balance Chart (KTBC) to evaluate the patients’ feeding status and examined its association with their nutritional status and prognosis. This study included elderly patients undergoing hemodialysis who were hospitalized at Nagasaki Renal Center for > 3 days between June 2021 and February 2022. In total, 82 inpatients were included [mean age, 73.4 ± 10.0 years; men, 57.3%; median dialysis vintage, 79.0 months (interquartile range, 37.3–164.8)]. We classified patients with lower than the median KTBC score (57 points) as being at risk for dysphagia; 37 patients (45.1%) were at risk for dysphagia. Spearman’s rank correlation coefficient (ρ) elucidated that the KTBC total score was significantly associated with each nutritional indicator [serum albumin level (ρ = 0.505, p < 0.001); geriatric nutritional risk index (ρ = 0.600, p < 0.001); and nutritional risk index (ρ = -0.566, p < 0.001)]. The KTBC score was also closely associated with the body mass index (ρ = 0.228, p = 0.04). Patients with a lower KTBC score showed poor prognosis (log-rank test: p = 0.001), and age- and sex-adjusted Cox proportional analysis showed that the KTBC score was associated with life prognosis (hazard ratio, 0.90; 95% confidential interval, 0.86–0.94; p < 0.001). Therefore, we concluded that the patients at risk of dysphagia, identified using the KTBC score, were malnourished and had a poor prognosis. Hence, the evaluation of dysphagia using the KTBC is encouraged to prevent malnutrition in vulnerable older patients undergoing hemodialysis

    Simultaneous Screening of Multiple Mutations by Invader Assay Improves Molecular Diagnosis of Hereditary Hearing Loss: A Multicenter Study

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    Although etiological studies have shown genetic disorders to be a common cause of congenital/early-onset sensorineural hearing loss, there have been no detailed multicenter studies based on genetic testing. In the present report, 264 Japanese patients with bilateral sensorineural hearing loss from 33 ENT departments nationwide participated. For these patients, we first applied the Invader assay for screening 47 known mutations of 13 known deafness genes, followed by direct sequencing as necessary. A total of 78 (29.5%) subjects had at least one deafness gene mutation. Mutations were more frequently found in the patients with congenital or early-onset hearing loss, i.e., in those with an awareness age of 0–6 years, mutations were significantly higher (41.8%) than in patients with an older age of awareness (16.0%). Among the 13 genes, mutations in GJB2 and SLC26A4 were mainly found in congenital or early-onset patients, in contrast with mitochondrial mutations (12S rRNA m.1555A>G, tRNA(Leu(UUR)) m.3243A>G), which were predominantly found in older-onset patients. The present method of simultaneous screening of multiple deafness mutations by Invader assay followed by direct sequencing will enable us to detect deafness mutations in an efficient and practical manner for clinical use

    Magmatic Products by Ocean Floor Spreading in MAR : Preliminary Analyses of Peridotites from IODP Exp.304/305 at Atlantis Massif, MAR 30°N

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    金沢大学大学院自然科学研究科4the International Symposium of the Kanazawa University 21st-Century COE Program, Promotion Envirnmental Research in Pan-Japan Sea Area -Young Researchers\u27 Network- , DATE:March 8-10,2006, PLACE: Kanazawa Excel Hotel Tokyu, Japan, Sponsors: Japan Sea Research Institute / UNU-IAS(United Nation University Institute of Advanced Studies), Ishikawa Prefectural Government, City of Kanazaw
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