149 research outputs found

    Analysis of Thermal Demagnetization Behavior of Nd–Fe–B Sintered Magnets Using Magnetic Domain Observation

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    We used magnetic domain observation to statistically observe the thermal demagnetization behavior of Nd–Fe–B sinteredmagnets at elevated temperatures up to 150 °C. Simultaneous magnetization reversal in a hundred adjacent grains occurred at 90 °C because of the magnetic interaction among the grains beyond grain boundaries in the Dysprosium (Dy)-free low-coercivity magnet. Conversely, simultaneous magnetization reversal in a hundred grains did not occur in the Dy-added high-coercivity magnets, and the demagnetizing ratio steadily increased with temperature. Furthermore, the addition of Dy induced high thermal stability by eliminating the simultaneous thermal demagnetization, which was caused by the magnetic interaction among the grains

    Analysis of Thermal Demagnetization Behavior of Nd–Fe–B Sintered Magnets Using Magnetic Domain Observation

    Get PDF
    We used magnetic domain observation to statistically observe the thermal demagnetization behavior of Nd–Fe–B sinteredmagnets at elevated temperatures up to 150 °C. Simultaneous magnetization reversal in a hundred adjacent grains occurred at 90 °C because of the magnetic interaction among the grains beyond grain boundaries in the Dysprosium (Dy)-free low-coercivity magnet. Conversely, simultaneous magnetization reversal in a hundred grains did not occur in the Dy-added high-coercivity magnets, and the demagnetizing ratio steadily increased with temperature. Furthermore, the addition of Dy induced high thermal stability by eliminating the simultaneous thermal demagnetization, which was caused by the magnetic interaction among the grains

    Advancements in Microscopic Observation Technology for Space Bio-Experiments

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    We are developing a unique one-chip microscopic observation device called Micro Imaging Device (MID) using semiconductor technology. MID does not require optical lenses, and directly detects the object of observation placed on a semiconductor sensor chip with densely arranged photodiodes. MID is a lightweight and compact digital control device, and has a high availability with lab automation for research that requires microscopic observation. This time, we have developed a Raspberry Pi-driven MID board specialized for use in lab automation. Raspberry Pi is a single-board computer used not only in electronics but also space missions, and the MID board we developed functions as a camera module for Raspberry Pi, making it possible to capture still images, videos, and time lapse according to the user\u27s needs. Furthermore, by using these as a core unit to control various electronic devices it has become possible to build a compact automated experimental unit. Currently, we are working on a space bio experiment service (Micro Bio Space LAB, MBS-LAB) to be installed on a satellite payload

    Artificial intelligence supported anemia control system (AISACS) to prevent anemia in maintenance hemodialysis patients

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    Anemia, for which erythropoiesis-stimulating agents (ESAs) and iron supplements (ISs) are used as preventive measures, presents important difficulties for hemodialysis patients. Nevertheless, the number of physicians able to manage such medications appropriately is not keeping pace with the rapid increase of hemodialysis patients. Moreover, the high cost of ESAs imposes heavy burdens on medical insurance systems. An artificial-intelligence-supported anemia control system (AISACS) trained using administration direction data from experienced physicians has been developed by the authors. For the system, appropriate data selection and rectification techniques play important roles. Decision making related to ESAs poses a multi-class classification problem for which a two-step classification technique is introduced. Several validations have demonstrated that AISACS exhibits high performance with correct classification rates of 72%-87% and clinically appropriate classification rates of 92%-98%

    Angiotensin II alters the expression of duodenal iron transporters, hepatic hepcidin, and body iron distribution in mice

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    Purpose: Angiotensin II (ANG II) has been shown to affect iron metabolism through alteration of iron transporters, leading to increased cellular and tissue iron contents. Serum ferritin, a marker of body iron storage, is elevated in various cardiovascular diseases, including hypertension. However, the associated changes in iron absorption and the mechanism underlying increased iron content in a hypertensive state remain unclear. Methods: C57BL6/J mice were treated with ANG II to generate a model of hypertension. Mice were divided into 3 groups: (1) control, (2) ANG II-treated, and (3) ANG II-treated and ANG II receptor blocker (ARB)-administered (ANG II-ARB) groups. Results: Mice treated with ANG II showed increased serum ferritin levels compared to vehicle-treated control mice. In ANG II-treated mice, duodenal divalent metal transporter-1 (DMT1) and ferroportin (FPN) expression levels were increased and hepatic hepcidin mRNA expression and serum hepcidin concentration were reduced. The mRNA expression of bone morphogenetic protein 6 (BMP6) and CCAAT/enhancer binding protein alpha (C/EBPα), which are regulators of hepcidin, was also down-regulated in the livers of ANG II-treated mice. In terms of tissue iron content, macrophage iron content and renal iron content were increased by ANG II treatment, and these increases were associated with reduced expression of transferrin receptor 1 and FPN and increased expression of ferritin. These changes induced by ANG II treatment were ameliorated by administration of an ARB. Conclusions: ANG II altered the expression of duodenal iron transporters and reduced hepcidin levels, contributing to the alteration of body iron distribution

    (-)-Pentazocine induces visceral chemical antinociception, but not thermal, mechanical, or somatic chemical antinociception, in μ-opioid receptor knockout mice

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    <p>Abstract</p> <p>Background</p> <p>(-)-Pentazocine has been hypothesized to induce analgesia via the κ-opioid (KOP) receptor, although the involvement of other opioid receptor subtypes in the effects of pentazocine remains unknown. In this study, we investigated the role of the μ-opioid (MOP) receptor in thermal, mechanical, and chemical antinociception induced by (-)-pentazocine using MOP receptor knockout (MOP-KO) mice.</p> <p>Results</p> <p>(-)-Pentazocine-induced thermal antinociception, assessed by the hot-plate and tail-flick tests, was significantly reduced in heterozygous and abolished in homozygous MOP-KO mice compared with wildtype mice. The results obtained from the (-)-pentazocine-induced mechanical and somatic chemical antinociception experiments, which used the hind-paw pressure and formalin tests, were similar to the results obtained from the thermal antinociception experiments in these mice. However, (-)-pentazocine retained its ability to induce significant visceral chemical antinociception, assessed by the writhing test, in homozygous MOP-KO mice, an effect that was completely blocked by pretreatment with nor-binaltorphimine, a KOP receptor antagonist. <it>In vitro </it>binding and cyclic adenosine monophosphate assays showed that (-)-pentazocine possessed higher affinity for KOP and MOP receptors than for δ-opioid receptors.</p> <p>Conclusions</p> <p>The present study demonstrated the abolition of the thermal, mechanical, and somatic chemical antinociceptive effects of (-)-pentazocine and retention of the visceral chemical antinociceptive effects of (-)-pentazocine in MOP-KO mice. These results suggest that the MOP receptor plays a pivotal role in thermal, mechanical, and somatic chemical antinociception induced by (-)-pentazocine, whereas the KOP receptor is involved in visceral chemical antinociception induced by (-)-pentazocine.</p

    Effect of Deferoxamine on Renal Fibrosis

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    Renal fibrosis plays an important role in the onset and progression of chronic kidney diseases (CKD). Although several mechanisms underlying renal fibrosis and candidate drugs for its treatment have been identified, the effect of iron chelator on renal fibrosis remains unclear. In the present study, we examined the effect of an iron chelator, deferoxamine (DFO), on renal fibrosis in mice with surgically induced unilateral ureter obstruction (UUO). Mice were divided into 4 groups: UUO with vehicle, UUO with DFO, sham with vehicle, and sham with DFO. One week after surgery, augmented renal tubulointerstitial fibrosis and the expression of collagen I, III, and IV increased in mice with UUO; these changes were suppressed by DFO treatment. Similarly, UUO-induced macrophage infiltration of renal interstitial tubules was reduced in UUO mice treated with DFO. UUO-induced expression of inflammatory cytokines and extracellular matrix proteins was abrogated by DFO treatment. DFO inhibited the activation of the transforming growth factor-β1 (TGF-β1)-Smad3 pathway in UUO mice. UUO-induced NADPH oxidase activity and p22phox expression were attenuated by DFO. In the kidneys of UUO mice, divalent metal transporter 1, ferroportin, and ferritin expression was higher and transferrin receptor expression was lower than in sham-operated mice. Increased renal iron content was observed in UUO mice, which was reduced by DFO treatment. These results suggest that iron reduction by DFO prevents renal tubulointerstitial fibrosis by regulating TGF-β-Smad signaling, oxidative stress, and inflammatory responses

    Transcatheter Arterial Chemoembolization to Reduce Size of Hepatocellular Carcinoma before Radiofrequency Ablation

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    Transcatheter arterial chemoembolization (TACE) is often performed before radiofrequency ablation (RFA) for the treatment of early-stage hepatocellular carcinoma (HCC). TACE prior to RFA can expand the ablated area and reduce the tumor size, facilitating complete ablation. However, the factors correlated with size reduction remain uncertain. The aim of this study was to identify the factors associated with size reduction by TACE and develop a formula to predict the reduction rate. A total of 100 HCC patients treated with TACE followed by RFA at least 20 days later were enrolled. The tumor size was measured at the time of TACE and RFA, and correlations between the reduction rate and 13 clinical factors were examined. A formula to predict the reduction rate was built using the factors obtained by the analysis. Reduction in the tumor size was observed in 69 nodules, and the median reduction rate was 16.2%. A multivariate regression analysis revealed that a large tumor size (p< 0.01) and a long interval between the therapies (p= 0.01) were factors for a high tumor reduction rate, with tumor size more strongly related to the degree of reduction. A size reduction of more than 10% can be expected by waiting 20 days after TACE when the size of the tumor at TACE is over 25 mm in diameter. The tumor siz

    Autophagy Plays an Essential Role in Mediating Regression of Hypertrophy during Unloading of the Heart

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    Autophagy is a bulk degradation mechanism for cytosolic proteins and organelles. The heart undergoes hypertrophy in response to mechanical load but hypertrophy can regress upon unloading. We hypothesize that autophagy plays an important role in mediating regression of cardiac hypertrophy during unloading. Mice were subjected to transverse aortic constriction (TAC) for 1 week, after which the constriction was removed (DeTAC). Regression of cardiac hypertrophy was observed after DeTAC, as indicated by reduction of LVW/BW and cardiomyocyte cross-sectional area. Indicators of autophagy, including LC3-II expression, p62 degradation and GFP-LC3 dots/cell, were significantly increased after DeTAC, suggesting that autophagy is induced. Stimulation of autophagy during DeTAC was accompanied by upregulation of FoxO1. Upregulation of FoxO1 and autophagy was also observed in vitro when cultured cardiomyocytes were subjected to mechanical stretch followed by incubation without stretch (de-stretch). Transgenic mice with cardiac-specific overexpression of FoxO1 exhibited smaller hearts and upregulation of autophagy. Overexpression of FoxO1 in cultured cardiomyocytes significantly reduced cell size, an effect which was attenuated when autophagy was inhibited. To further examine the role of autophagy and FoxO1 in mediating the regression of cardiac hypertrophy, beclin1+/2 mice and cultured cardiomyocytes transduced with adenoviruses harboring shRNA-beclin1 or shRNA-FoxO1 were subjected to TAC/ stretch followed by DeTAC/de-stretch. Regression of cardiac hypertrophy achieved after DeTAC/de-stretch was significantly attenuated when autophagy was suppressed through downregulation of beclin1 or FoxO1. These results suggest that autophagy and FoxO1 play an essential role in mediating regression of cardiac hypertrophy during mechanical unloading
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