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71.
Accurate measurements have been made to determine radiation transmission of concretes produced with barite, colemanite and normal aggregate by using beam transmission method for 0.663 MeV γ-rays energy of 137Cs radioactive isotopes by using NaI(Tl) scintillation detector. Linear and mass attenuation coefficients of thirteen heavy- and four normal-weight concretes were calculated. It was determined that the linear attenuation coefficient (μ, cm−1) decreased with colemanite concentration and increased with barite concentration in both type of the concretes. Mass attenuation coefficient values of our concretes were compared with the values proposed by the United States National Institute of Standards and Technology (NIST). 相似文献
72.
Philipp Kasper Jaco Selle Christina Vohlen Rebecca Wilke Celien Kuiper-Makris Oleksiy Klymenko Inga Bae-Gartz Charlotte Schmig Alexander Quaas Bjrn Schumacher Münevver Demir Martin Bürger Sonja Lang Anna Martin Hans-Michael Steffen Tobias Goeser Jrg Dtsch Miguel A. Alejandre Alcazar 《International journal of molecular sciences》2022,23(10)
Maternal obesity predisposes for hepato-metabolic disorders early in life. However, the underlying mechanisms causing early onset dysfunction of the liver and metabolism remain elusive. Since obesity is associated with subacute chronic inflammation and accelerated aging, we test the hypothesis whether maternal obesity induces aging processes in the developing liver and determines thereby hepatic growth. To this end, maternal obesity was induced with high-fat diet (HFD) in C57BL/6N mice and male offspring were studied at the end of the lactation [postnatal day 21 (P21)]. Maternal obesity induced an obese body composition with metabolic inflammation and a marked hepatic growth restriction in the male offspring at P21. Proteomic and molecular analyses revealed three interrelated mechanisms that might account for the impaired hepatic growth pattern, indicating prematurely induced aging processes: (1) Increased DNA damage response (γH2AX), (2) significant upregulation of hepatocellular senescence markers (Cdnk1a, Cdkn2a); and (3) inhibition of hepatic insulin/insulin-like growth factor (IGF)-1-AKT-p38-FoxO1 signaling with an insufficient proliferative growth response. In conclusion, our murine data demonstrate that perinatal obesity induces an obese body composition in male offspring with hepatic growth restriction through a possible premature hepatic aging that is indicated by a pathologic sequence of inflammation, DNA damage, senescence, and signs of a possibly insufficient regenerative capacity. 相似文献
73.
Biological and chemical removal of Cr(VI) from waste water: cost and benefit analysis 总被引:1,自引:0,他引:1
The objective of the present study is cost and benefit analysis of biological and chemical removal of hexavalent chromium [Cr(VI)] ions. Cost and benefit analysis were done with refer to two separate studies on removal of Cr(VI), one of heavy metals with a crucial role concerning increase in environmental pollution and disturbance of ecological balance, through biological adsorption and chemical ion-exchange. Methods of biological and chemical removal were compared with regard to their cost and percentage in chrome removal. According to the result of the comparison, cost per unit in chemical removal was calculated 0.24 euros and the ratio of chrome removal was 99.68%, whereas those of biological removal were 0.14 and 59.3% euros. Therefore, it was seen that cost per unit in chemical removal and chrome removal ratio were higher than those of biological removal method. In the current study where chrome removal is seen as immeasurable benefit in terms of human health and the environment, percentages of chrome removal were taken as measurable benefit and cost per unit of the chemicals as measurable cost. 相似文献
74.
75.
This study presents the potential of the burning and/or transmutation (B/T) of transuraniums (TRUs), discharged from the pressured water reactor PWR-UO2 spent fuel, in the modified PROMETHEUS-H fusion reactor. Two different design shapes (Models A and B) were considered. The transmutation zone (TZ), which contains the mixture of TRU nuclides (10%), was located in the modified blankets. The volume fraction of Pu in the mixture is raised from 0 to 40% stepped by 10% to determine its effect on the B/T. The fuel spheres were cladded with SiC (5%) and cooled with high-pressured helium gas (85%) for nuclear heat transfer. The calculations were performed for an operation period (OP) of up to 10 years by 75% plant factor (η) under a neutron wall load (P) of 4.7 MW/m2. The results bring out that: (1) the Model B transmutes the TRUs more rapidly than the Model A; (2) the effective half-lives decrease about 20 and 40% with the increase of Pu fraction in the cases of Models A and B, respectively; (3) the M values are quite high with respect to the M value of the original PROMETHEUS fusion reactor; (4) the blankets can produce substantial electricity in situ. 相似文献
76.
Injuries to the bowel and mesentery are found in approximately 5% of all patients undergoing laparotomy after blunt abdominal trauma. Bowel and mesenteric injuries are often subtle and difficult to diagnose, and a delay in the diagnosis is associated with increased mortality and morbidity. CT is the best imaging method for diagnosing injuries to the bowel and mesentery. With meticulous scanning techniques, most significant bowel and mesenteric injuries can be reliably identified with CT preoperatively, and associated injuries to other abdominal viscera can be confirmed. 相似文献
77.
UP Schmiedl C Yuan HV Nghiem TC Winter PC Freeny 《Canadian Metallurgical Quarterly》1996,17(4):404-411
MR angiography (MRA) for the evaluation of peripheral arterial occlusive disease is a rapidly evolving technique. Recent prospective clinical trials have indicated that MRA may play an important role in the evaluation of patients with peripheral arterial disease. This article discusses the pertinent technical aspects and limitations of peripheral MRA as well as some of the clinical data available. 相似文献
78.
79.
HV Forster LG Pan TF Lowry T Feroah WM Gershan AA Whaley MM Forster B Sprtel 《Canadian Metallurgical Quarterly》1998,84(1):129-140
Recent scientific studies have demonstrated the efficacy of various forms of immunotherapy for the treatment of allergic diseases. Traditional subcutaneous immunotherapy, sublingual, oral, and intranasal immunotherapy have been shown to significantly reduce symptoms and favorably modulate the immune response. Outcome studies that use patient response data from standardized surveys represent the next challenge to all practicing allergists. 相似文献
80.
For an antenna array, different feed structure topologies may yield the same radiation characteristics. However, different topologies may result in different efficiency and noise performance. In this paper, parallel arm antenna arrays are analyzed for efficiency and noise temperature using the noise equivalent line length method (NELL) with the number of antenna elements in a subarray as a parameter. It is shown that efficiency of an antenna array feed structure as well as its noise temperature can be calculated using the NELL method. The comparison of the two parameters, efficiency and noise temperature, yield the optimum number of antenna elements in a subarray of a parallel arm antenna array for the highest G/T ratio. 相似文献