Embrittlement mechanisms of nickel-base alloys in water

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1987.Bibliography: v. 2, leaves 498-511.by Il Soon Hwang.Ph.D

Electrolytic Recovery of High Purity Zr from Radioactively Contaminated Zr Alloys in Chloride Salts

It has been believed that high purity Zr metal is hard to be prepared from Zr alloys in LiCl-KCl salts since Zr has various redox reactions in LiCl-KCl including insoluble ZrCl formation and disproportionate reaction between Zr and Zr4+. We examined electrolytic Zr recovery from Zircaloy-4 by controlling anodic potential at five concentrations of ZrCl4 in LiCl-KCl salts. Anode potential of - 0.9 V (vs. Ag/AgCl) was applied to prevent the elements except Zr being dissolved from the anode into the electrolyte. Experimental results showed Zr with purity of over 99.9% was recovered and all alloying elements were analyzed below their detection limit in ICP-MS. In addition, at low ZrCl4 concentrations of 0.1 and 0.5 wt.%, the chemical form of the cathode deposits was Zr metal without ZrCl while only ZrCl without Zr metal was recovered at the high ZrCl4 concentration, 2.0 and 4.0 wt.%. At the ZrCl4 concentration of 1.0 wt.%, both Zr metal and ZrCl were recovered. Therefore, preparation of high purity Zr metal from Zr alloys is feasible in LiCl-KCl at low concentration of ZrCl4

Antidiabetic Effect of Fresh Nopal ( Opuntia ficus-indica

The objective of the present study was to evaluate α-glucosidase inhibitory and antidiabetic effects of Nopal water extract (NPWE) and Nopal dry power (NADP) in low-dose streptozotocin- (STZ-) induced diabetic rats fed a high-fat diet (HFD). The type 2 diabetic rat model was induced by HFD and low-dose STZ. The rats were divided into four groups as follows: (1) nondiabetic rats fed a regular diet (RD-Control); (2) low-dose STZ-induced diabetic rats fed HFD (HF-STZ-Control); (3) low-dose STZ-induced diabetic rats fed HFD and supplemented with NPWE (100 mg/kg body weight, HF-STZ-NPWE); and (4) low-dose STZ-induced diabetic rats fed HFD and supplemented with comparison medication (rosiglitazone, 10 mg/kg, body weight, HF-STZ-Rosiglitazone). In results, NPWE and NADP had IC50 values of 67.33 and 86.68 μg/mL, both of which exhibit inhibitory activities but lower than that of acarbose (38.05 μg/mL) while NPWE group significantly decreased blood glucose levels compared to control and NPDP group on glucose tolerance in the high-fat diet fed rats model (P<0.05). Also, the blood glucose levels of HR-STZ-NPWE group were significantly lower (P<0.05) than HR-STZ-Control group on low-dose STZ-induced diabetic rats fed HFD. Based on these findings, we suggested that NPWE could be considered for the prevention and/or treatment of blood glucose and a potential use as a dietary supplement

Upper Eyelid Retraction After Periorbital Trauma

We report four unusual cases of upper eyelid retraction following periorbital trauma. Four previously healthy patients were evaluated for unilateral upper eyelid retraction following periorbital trauma. A 31-year-old man (Case 1) and a 24-year-old man (Case 2) presented with left upper eyelid retraction which developed after blow-out fractures, a 44-year-old woman (Case 3) presented with left upper eyelid retraction secondary to a periorbital contusion that occurred one week prior, and a 56-year-old man (Case 4) presented with left upper eyelid retraction that developed 1 month after a lower canalicular laceration was sustained during a traffic accident. The authors performed a thyroid function test and orbital computed tomography (CT) in all cases. Thyroid function was normal in all patients, CT showed an adhesion of the superior rectus muscle and superior oblique muscle in the first case and diffuse thickening of the superior rectus muscle and levator complex in the third case. CT showed no specific findings in the second or fourth cases. Upper eyelid retraction due to superior complex adhesion can be considered one of the complications of periorbital trauma

Overexpression of Arabidopsis thaliana brassinosteroid-related acyltransferase 1 gene induces brassinosteroid-deficient phenotypes in creeping bentgrass

Brassinosteroids (BRs) are naturally occurring steroidal hormones that play diverse roles in various processes during plant growth and development. Thus, genetic manipulation of endogenous BR levels might offer a way of improving the agronomic traits of crops, including plant architecture and stress tolerance. In this study, we produced transgenic creeping bentgrass (Agrostis stolonifera L.) overexpressing a BR-inactivating enzyme, Arabidopsis thaliana BR-related acyltransferase 1 (AtBAT1), which is known to catalyze the conversion of BR intermediates to inactive acylated conjugates. After putative transgenic plants were selected using herbicide resistance assay, genomic integration of the AtBAT1 gene was confirmed by genomic PCR and Southern blot analysis, and transgene expression was validated by northern blot analysis. The transgenic creeping bentgrass plants exhibited BR-deficient phenotypes, including reduced plant height with shortened internodes (i.e., semi-dwarf), reduced leaf growth rates with short, wide, and thick architecture, high chlorophyll contents, decreased numbers of vascular bundles, and large lamina joint bending angles (i.e., erect leaves). Subsequent analyses showed that the transgenic plants had significantly reduced amounts of endogenous BR intermediates, including typhasterol, 6-deoxocastasterone, and castasterone. Moreover, the AtBAT1 transgenic plants displayed drought tolerance as well as delayed senescence. Therefore, the results of the present study demonstrate that overexpression of an Arabidopsis BR-inactivating enzyme can reduce the endogenous levels of BRs in creeping bentgrass resulting in BR-deficient phenotypes, indicating that the AtBAT1 gene from a dicot plant is also functional in the monocot crop.111Ysciescopu

High-Temperature Corrosion Behaviors of Structural Materials for Lead-Alloy-Cooled Fast Reactor Application

The corrosion of nuclear-grade steels in lead-bismuth eutectic (LBE) complicates the realization of high coolant temperatures. Corrosion tests of T91, HT9, and SS316L were performed in static cells at 600 degrees C for 2000 h at an oxygen level of 10(-6) wt.%. The obtained corrosion surfaces of post-processed samples were characterized by several microscopy methods. Up to 1000 h, all the alloys exhibited an evolution of duplex oxide layers, which were spalled until 2000 h due to their increased thickness and decreased integrity. Following the spallation, a thin internal Cr-rich oxide layer was formed above the Cr-depleted zone for T91 and HT9. SS316L was penetrated by LBE down to 300 mu m in severe cases. A comparison on the corrosion depths of the materials with regard to the parabolic oxidation law with abundant literature data suggests that it may lose its validity once the duplex layer is destroyed as it allows LBE to penetrate the metal substrate

Forage Rye Cultivars for Animal Feed in Korea

Rye (Secale cereal L.) is well known for its overwintering ability and has the highest tolerance to cold temperature of the small grain cereals such as wheat, barley, and oat. Rye is used as livestock pasture and as green manure in Korea, and its cultivation area for fodder is about 50,000 ha in 2014. Most rye is grown as a fall-sown annual crop, generally called “winter rye”. In Korea, rye cultivation for whole crop silage (WCS) in the winter-season rice field can be considered as a promising way to enhance feed supply. The WCS production can be an efficient way to use farm products as livestock feed, and it can also contribute to increasing farm income. Although rye is inferior in several ways to the predominant cereal crops (wheat, rice, and maize), it will continue to be an important crop for farmers in Korea because of its winter hardiness and early harvesting by rapid growing ability