463 research outputs found

    Unbundling of electricity transmission system operators in Germany: An experience report

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    The purpose of this research is to evaluate the impact of vertical unbundling on German electric utilities. Our research mainly relies on in-depth interviews with sector-experts from the German utilities. We will discuss both short-term changes and the long-term impact on competition in the electricity market as well as the impact on costs and security of supply. Overall, we have two main conclusions. First, the major step in the unbundling process is from "lean legal unbundling" to "fat legal unbundling"; additional steps beyond that are small, both in benefits and in costs. Second, the benefits of unbundling in terms of increased competition do not come for free: unbundling is costly and it is important to balance cost and benefits in the reform process

    Visualization of Stent Lumen in MR Imaging: Relationship with Stent Design and RF Direction

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    Magnetic resonance imaging (MRI) visualization of metallic stent lumens is possible if the stent structure counteracts eddy currents in the lumen induced by the radio frequency magnetic field, B1. To examine the effectiveness of various stent designs in counteracting eddy currents, we anchored eight copper stent models and 2 commercially available nickel-titanium alloy (Nitinol) stents in a gel phantom, perpendicular or parallel to the direction of B1. A mesh stent lumen showed hypointensity irrespective of its alignment relative to B1. A solenoid stent lumen showed hypointensity with the stent axis parallel to B1, but it had the same signal intensity as outside the lumen when perpendicular to B1. A Moebius stent lumen showed no signal reduction, irrespective of alignment relative to B1. Lumens of the commercially available stents showed hypointensity regardless of alignment relative to B1. Computer simulation revealed that the signal intensities of the stents corresponded to magnetic flux densities of B1 in the stents, which are modified by the structure of the stent. While in vivo MRI viewing of a Moebius stent lumen is likely possible regardless of axis alignment, inherent structural weakness may be problematic. As a more practical choice, the solenoid stent is easier to manufacture and generates no hypointensive signal when the axis is parallel to B0

    Seismic performance of group pile foundation with ground improvement during liquefaction

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    A pile foundation with ground improvement under the footing is a composite foundation with the objectives of enhancing the seismic performance and rationalizing the substructure by combining the pile foundation with ground improvement. Although the effectiveness of this method has been confirmed in previous studies for application to soft grounds, the applicability of this method to liquefiable grounds has yet to be fully investigated. In this study, therefore, centrifuge model tests and finite element analyses were conducted to clarify the effectiveness of this method and to ascertain the improvement in strength (stiffness) when the method is applied to a liquefiable ground. Firstly, in order to investigate the effect of an improved ground on the behavior of the pile foundation during liquefaction, dynamic centrifuge model tests were conducted for three cases with different strengths of the improved ground. Then, three-dimensional soil–water coupled finite element analyses of the centrifuge model experiments were performed to validate the applicability of the analytical method. After that, parametric studies, in which the strength of the improved ground and the input ground motion were changed, were conducted using the same analytical model. The results confirmed that the horizontal displacement of the pile heads was reduced by the improved ground even in the liquefiable ground, and that the effect of this reduction was more remarkable in cases of high stiffness of the improved ground. Furthermore, it was possible to reduce the bending moments at the pile heads by applying the ground improvement. However, since the bending moment at the boundary between the improved ground and the natural ground became the local maximum, there was an optimum stiffness of the ground improvement at which the maximum bending moment of the piles was reduced. This is because improving the ground around the pile heads has the same effect as extending the footing. It was thus concluded that the behavior of the pile foundation is similar to that of a composite foundation comprised of a caisson and group piles

    Enhanced visualization of the portal vein system in superior mesenteric arterial portography using prostaglandin E1.

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    The portal vein system was clearly visualized in superior mesenteric arterial portography using prostaglandin E1. Angiographic examination was performed in 68 patients with various liver diseases during the 2 year period from 1980 to 1981. Twenty microgram of prostaglandin E1 was injected into the superior mesenteric artery 30 seconds before injection of 60 ml of contrast medium. The main portal vein was visualized in all of 68 cases. A high rate of success for visualization of the intrahepatic portal vein system by prostaglandin E1 was achieved. The first branches of the intrahepatic portal vein were visualized in 100% of the cases, the second branches in 82%, the third branches in 44%, and the fourth branches in 4% in the right portal vein system. In the left portal vein system, the first branches were visualized in 87%, the second branches in 41%, and the third branches in 3% of the cases. The intrahepatic portal vein system was more clearly visualized in females than in males (P less than 0.05). This procedure is simple, safe and useful for clear visualization of the portal vein system.</p

    Load carrying behavior of concrete reinforced with bundled BFRP bars by using DIC

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    Recently, basalt fiber-reinforced polymer (BFRP) has gained attention in the construction industry because of its worldwide availability and eco-friendly nature. Different from conventional steel bars, BFRP bar do not corrode being an ideal reinforcing material in structures surrounding magnetic fields and marine environments, given its chemical stability. This study investigated the load carrying behavior of concrete beams reinforced with conventional deformed steel bars and seven-bundled BFRP bars through four-point flexural test. For each case, two beams were pre-pared; one beam was designed with a low reinforcement ratio and another with a high rein-forcement ratio in order to obtain a load carrying capacity of around 330-368 kN and 483-519 kN, respectively. Deflection, crack width evolution, and strain behavior of each beam were comparatively analyzed using a digital image correlation (DIC) based technique. The DIC analysis results showed that the neutral axis of bundled BFRP reinforced cases move to the upper end in an early loading stage, with larger cracks width, and the deflection is larger in BFRP cases than in those of steel-reinforced beams with the respective reinforcement ratio. However, the four-point flexural test results revealed that bundled BFRP bars can be used as an alternative to conventional steel bars. The load carrying capacities were obtained similarly to designed values, around 364 and 551 kN for low and high reinforcement ratio cases, respectively

    Rikkunshito Ameliorates Cancer Cachexia Partly through Elevation of Glucarate in Plasma

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    Cancer cachexia, which is characterized by decreased food intake, weight loss and systemic inflammation, increases patient’s morbidity and mortality. We previously showed that rikkunshito (RKT), a Japanese traditional herbal medicine (Kampo), ameliorated the symptoms of cancer cachexia through ghrelin signaling-dependent and independent pathways. To investigate other mechanisms of RKT action in cancer cachexia, we performed metabolome analysis of plasma in a rat model bearing the Yoshida AH-130 hepatoma. A total of 110 metabolites were detected in plasma and RKT treatment significantly altered levels of 23 of those metabolites in cachexia model rats. Among them, glucarate, which is known to have anticarcinogenic activity through detoxification of carcinogens via inhibition of β-glucuronidase, was increased in plasma following administration of RKT. In our AH-130 ascites-induced cachexia rat model, administration of glucarate delayed onset of weight loss, improved muscle atrophy, and reduced ascites content. Additionally, glucarate reduced levels of plasma interferon-γ (IFN-γ) in tumor-bearing rats and was also found to suppress LPS-induced IFN-γ expression in splenocytes in vitro. These results suggest that glucarate has anti-inflammatory activity via a direct effect on immune host cells and suggest that RKT may also ameliorate inflammation partly through the elevation of glucarate in plasma
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