632 research outputs found

    Vascular Sphincter and Microangioarchitecture in the Central Nervous System: Constriction of Intraparenchymal Blood Vessels Following a Treatment of Vasoconstrictive Neurotransmitter

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    The site of action of neuropeptide Y (NPY), a potent vasoconstrictive neurotransmitter, on the intraparenchymal blood vessels in the rat parietal cortex was demonstrated using a corrosion cast technique with scanning electron microscopy. Our observations were confined to the cortical area where the regional cerebral blood flow (rCBF) had been reduced significantly by in situ application of NPY. A striking finding in that area was the diffuse narrowing of the perforating arteries in the upper cortical layers. Ring-like compressions on the corrosion casts, presumably formed by active vascular sphincters along the arteries, capillaries and venules within the brain parenchyma, seemed to be more prominent in the perforating arteries of the NPY-treated cortex as compared with those of control cortex. We conclude that NPY-containing nerve fibers along the parenchymal blood vessels may take part in regulating the rCBF primarily by reducing the caliber of the proximal perforating arteries

    Rethinking Site Selection Approaches for Geological Disposal of High-Level Radioactive Waste from a Social Psychological Viewpoint

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    ABSTRACT With growing concern about global warming and the increasing demand for energy, the use of nuclear power is expected to increase in both developed and developing countries. However, the safe disposal of radioactive waste, especially high-level radioactive waste (HLW), generated by nuclear power plants, remains an urgent and challenging issue that may affect sustainable development and utilization of nuclear energy in the future. Many countries, including the USA, Germany, France, Canada, Switzerland, Belgium, Japan, Sweden, and Finland, have had radioactive waste management programs for many years, but the plans and schedules in many countries have changed or even been suspended. Only Finland and Sweden have recently decided on sites for final disposal of HLW. Here, we first present a brief overview of nuclear energy around the world, and introduce the situations related to energy, nuclear power, and management of HLW in Japan. Then, we discuss the processes and progress made related to waste management programs in several countries. Difficulties associated with geological disposal of HLW in Japan have been analyzed from a variety of aspects, including geological and hydrogeological conditions, historical, social, and cultural backgrounds. Discussion of the advantages and disadvantages of the two site selection approaches, i.e., the so-called "volunteer approach" and "invitation approach," are presented from a social psychological viewpoint. Some considerations for reaching agreements and public acceptance are provided

    Development of a field measurement system for the Bulk HTSC SAU

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    11th International Conference on Synchrotron Radiation Instrumentation (SRI 2012)To realize a short-period strong-field undulator, we proposed a high temperature superconducting bulk staggered array undulator (Bulk HTSC SAU) and proceeded proof of principle experiments and numerical studies. We have succeeded to generate periodic transverse magnetic fields whose strength was controlled by an external solenoid field. At the same time, we revealed a problem; at both ends of undulator, field distribution is substantially distorted. We proposed several approaches of field correction. To verify the effectiveness of these field correction methods, it is necessary to measure the magnetic field distribution precisely, not only inside of the undulator but also both ends. For this purpose, we developed a rotary measurement system to measure the magnetic field distribution at the end of the undulator. Multiple Hall sensors are placed on a circuit board at equal intervals from the centre of the board. By rotating and moving the board, the probe can measure axial field in 3D space on the undulator ends. In this paper, we deliver specifics of the system

    Design Study for Direction Variable Compton Scattering Gamma Ray

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    11th International Conference on Synchrotron Radiation Instrumentation (SRI 2012)A monochromatic gamma ray beam is attractive for isotope-specific material/medical imaging or non-destructive inspection. A laser Compton scattering (LCS) gamma ray source which is based on the backward Compton scattering of laser light on high-energy electrons can generate energy variable quasi-monochromatic gamma ray. Due to the principle of the LCS gamma ray, the direction of the gamma beam is limited to the direction of the high-energy electrons. Then the target object is placed on the beam axis, and is usually moved if spatial scanning is required. In this work, we proposed an electron beam transport system consisting of four bending magnets which can stick the collision point and control the electron beam direction, and a laser system consisting of a spheroidal mirror and a parabolic mirror which can also stick the collision point. Then the collision point can be placed on one focus of the spheroid. Thus gamma ray direction and collision angle between the electron beam and the laser beam can be easily controlled. As the results, travelling direction of the LCS gamma ray can be controlled under the limitation of the beam transport system, energy of the gamma ray can be controlled by controlling incident angle of the colliding beams, and energy spread can be controlled by changing the divergence of the laser beam

    Stress corrosion cracking in Al-Zn-Mg-Cu aluminum alloys in saline environments

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    Copyright 2013 ASM International. This paper was published in Metallurgical and Materials Transactions A, 44A(3), 1230 - 1253, and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 Β°C to 80 Β°C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack (β€œpop-in” vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies (E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 Β°C to 80 Β°C) for under-, peak-, and over-aged low-copper-containing alloys (~0.8 wt pct), they are typically ranging from 20 to 40 kJ/mol for under- and peak-aged alloys, and based on limited data, around 85 kJ/mol for over-aged tempers. This means that crack propagation in saline environments is most likely to occur by a hydrogen-related process for low-copper-containing Al-Zn-Mg-Cu alloys in under-, peak- and over-aged tempers, and for high-copper alloys in under- and peak-aged tempers. For over-aged high-copper-containing alloys, cracking is most probably under anodic dissolution control. Future stress corrosion studies should focus on understanding the factors that control crack initiation, and insuring that the next generation of higher performance Al-Zn-Mg-Cu alloys has similar longer crack initiation times and crack propagation rates to those of the incumbent alloys in an over-aged condition where crack rates are less than 1 mm/month at a high stress intensity factor

    Successful Treatment of Novel H1N1 Influenza related Fulminant Myocarditis with Extracorporeal Life Support

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    The prevalence of myocardial involvement in influenza infection ranges from 0% to 12%. The 2009 pH1N1 influenza virus, formerly known as swine flu, first appeared in Mexico and the United States of America in March and April 2009 and has swept the globe with unprecedented speed. We report a case of fulminant myocarditis associated with this virus treated successfully using extra-corporal membrane oxygenator

    Increased serum hepcidin-25 level and increased tumor expression of hepcidin mRNA are associated with metastasis of renal cell carcinoma

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    <p>Abstract</p> <p>Background</p> <p>Hepcidin has an important role in iron metabolism. We investigated whether hepcidin was involved in renal cell carcinoma (RCC).</p> <p>Methods</p> <p>We measured serum hepcidin-25 levels in 32 patients by liquid chromatograpy (LC)-mass spectrometry (MS)/MS, and assessed hepcidin mRNA expression in paired tumor and non-tumor tissue samples from the surgical specimens of 53 consecutive patients with RCC by real-time reverse transcription polymerase chain reaction.</p> <p>Results</p> <p>The serum hepcidin-25 level was higher in patients with metastatic RCC than nonmetastatic RCC (<it>P </it>< 0.0001), and was positively correlated with the serum interleukin-6 and C-reactive protein levels (<it>P </it>< 0.001). Expression of hepcidin mRNA was lower in tumor tissues than in non-tumor tissues (<it>P </it>< 0.0001). The serum hepcidin-25 level was not correlated with the expression of hepcidin mRNA in the corresponding tumor tissue specimens from 32 patients. Hepcidin mRNA expression in tumor tissue was correlated with metastatic potential, but not with histological differentiation or tumor stage. Kaplan-Meier analysis showed that over expression of hepcidin mRNA was related to shorter overall survival in RCC patients. Univariate analysis (Cox proportional hazards model) showed that the hepcidin mRNA level was an independent prognostic factor for overall survival.</p> <p>Conclusion</p> <p>Our findings suggest that a high serum hepcidin-25 level may indicate the progression of RCC, and that upregulation of hepcidin mRNA expression in tumor tissue may be related to increased metastatic potential.</p

    Intestine-Specific, Oral Delivery of Captopril/Montmorillonite: Formulation and Release Kinetics

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    The intercalation of captopril (CP) into the interlayers of montmorillonite (MMT) affords an intestine-selective drug delivery system that has a captopril-loading capacity of up to ca. 14 %w/w and which exhibits near-zero-order release kinetics

    Insulin resistance, adiponectin and adverse outcomes following elective cardiac surgery: a prospective follow-up study

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    <p>Abstract</p> <p>Background</p> <p>Insulin resistance and adiponectin are markers of cardio-metabolic disease and associated with adverse cardiovascular outcomes. The present study examined whether preoperative insulin resistance or adiponectin were associated with short- and long-term adverse outcomes in non-diabetic patients undergoing elective cardiac surgery.</p> <p>Methods</p> <p>In a prospective study, we assessed insulin resistance and adiponectin levels from preoperative fasting blood samples in 836 patients undergoing cardiac surgery. Population-based medical registries were used for postoperative follow-up. Outcomes included all-cause death, myocardial infarction or percutaneous coronary intervention, stroke, re-exploration, renal failure, and infections. The ability of insulin resistance and adiponectin to predict clinical adverse outcomes was examined using receiver operating characteristics.</p> <p>Results</p> <p>Neither insulin resistance nor adiponectin were statistically significantly associated with 30-day mortality, but adiponectin was associated with an increased 31-365-day mortality (adjusted odds ratio 2.9 [95% confidence interval 1.3-6.4]) comparing the upper quartile with the three lower quartiles. Insulin resistance was a poor predictor of adverse outcomes. In contrast, the predictive accuracy of adiponectin (area under curve 0.75 [95% confidence interval 0.65-0.85]) was similar to that of the EuroSCORE (area under curve 0.75 [95% confidence interval 0.67-0.83]) and a model including adiponectin and the EuroSCORE had an area under curve of 0.78 [95% confidence interval 0.68-0.88] concerning 31-365-day mortality.</p> <p>Conclusions</p> <p>Elevated adiponectin levels, but not insulin resistance, were associated with increased mortality and appear to be a strong predictor of long-term mortality. Additional studies are warranted to further clarify the possible clinical role of adiponectin assessment in cardiac surgery.</p> <p>Trial Registration</p> <p>The Danish Data Protection Agency; reference no. 2007-41-1514.</p

    Bone Marrow-Derived Progenitor Cells Augment Venous Remodeling in a Mouse Dorsal Skinfold Chamber Model

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    The delivery of bone marrow-derived cells (BMDCs) has been widely used to stimulate angiogenesis and arteriogenesis. We identified a progenitor-enriched subpopulation of BMDCs that is able to augment venular remodeling, a generally unexplored area in microvascular research. Two populations of BMDCs, whole bone marrow (WBM) and Linβˆ’/Sca-1+ progenitor cells, were encapsulated in sodium alginate and delivered to a mouse dorsal skinfold chamber model. Upon observation that encapsulated Sca-1+ progenitor cells enhance venular remodeling, the cells and tissue were analyzed on structural and molecular levels. Venule walls were thickened and contained more nuclei after Sca-1+ progenitor cell delivery. In addition, progenitors expressed mRNA transcript levels of chemokine (C-X-C motif) ligand 2 (CXCL2) and interferon gamma (IFNΞ³) that are over 5-fold higher compared to WBM. Tissues that received progenitors expressed significantly higher protein levels of vascular endothelial growth factor (VEGF), monocyte chemotactic protein-1 (MCP-1), and platelet derived growth factor-BB (PDGF-BB) compared to tissues that received an alginate control construct. Nine days following cell delivery, tissue from progenitor recipients contained 39% more CD45+ leukocytes, suggesting that these cells may enhance venular remodeling through the modulation of the local immune environment. Results show that different BMDC populations elicit different microvascular responses. In this model, Sca-1+ progenitor cell-derived CXCL2 and IFNΞ³ may mediate venule enlargement via modulation of the local inflammatory environment
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