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1.
The phase diagram for the system Bi2O3-B2O3 has been determined experimentally. The melting point of Bi2O3 has been redetermined as 825° C with an estimated overall uncertainty of about ±3°C, and the molal heat of fusion of Bi2O3, calculated from the slope of the liquidus curve, is 2050 cal per mole. The system contains a body-centered cubic phase of approximate composition 12Bi2O3·B2O3, which melts incongruently at 632°C. Four congruently melting compounds exist in the system: 2Bi2O3· B2O3·5B2O3, Bi2O3·3B2O3, and Bi2O3·4B2O3, with melting points, respectively, of 675°, 722°, 708°, and 715°C. The Bi2O3·4B2O3 compound exhibits a sluggish transformation at 696°C. Compositions containing up to 97.5 wt% (85 mole %) Bi2O3 can be partly or totally quenched to glass. Indices of the quenched glasses are greater than 1.74. A region of liquid immiscibility extends at 709°C from almost pure B2O3 to 19.0 mole % Bi2O3. The extent of immiscibility theoretically calculated agrees with the experimentally determined value when 1.20 A is used for the ionic radius of Bi3+. 相似文献
2.
ERNEST M. LEVIN CARL R. ROBBINS JON L. WARING 《Journal of the American Ceramic Society》1961,44(2):87-91
The phase equilibrium diagram for the system La2 O3 -B2 O3 has been determined experimentally. The compounds La2 O3 -3B2 O3 and La2 O3 -B2 O3 melt congruently at 1141°± 5°C. and 1660°± 15°C, respectively. At 1488°± 5°C, La2 O3 -B2 O3 inverts from the aragonite-type structure to a high-temperature form. Trilanthanum borate, 3La2 O3 B2 O3 , melts incongruently at 1386°± 5°C. to give liquid and La2 O3 . No solid solutions exist in the system. A region of liquid immiscibility exists in the system and extends at 1136°± 5°C. from almost pure B2 O3 to 21.5 mole % La2 O3 . The experimental value for the extent of immiscibility agrees with that calculated from theoretical considerations. A second method for estimating immiscibility in the system is demonstrated, which requires experimentally only the determination of the index of refraction of the modifier-rich liquid. Principles governing immiscibility are discussed. 相似文献
3.
ABSTRACT The purpose of this study was to determine the optimum concentration of blackstrap molasses required in conjunction with the use of several species of homofermentative lactic acid bacteria in the fermentation of hydrolyzed cod gurry. Blackstrap molasses at a concentration of 7.5% was found to be optimum for achieving a successful lactic acid fermentation of hydrolyzed cod gurry. Among the three homofermentative lactic acid bacteria studied (Lactobacillus plantarum, Pediococcus acidilactici and Streptococcus faecium) L. plantarum resulted in the most rapid fementation. S. faecium was the least desirable bacterium on the basis of fermentation rates and extent of pH decrease after 72 h of incubation. All three organisms failed to utilize significantly the sucrose derived from molasses, even though sucrose was the most abundant carbohydrate in the molasses. P. acidilactici was unable to utilize sucrose when present as a sole carbohydrate, while L. plantarum and S. faecium decreased the pH in broth cultures with sucrose as a sole carbohydrate. These results suggest that glucose in molasses functions as a repressor of invertase formation in L. plantarum and S. faecium, and that the use of derepressed mutants should allow a significant decrease in the amount of molasses required for a satisfactory fermentation. 相似文献
4.
This Paper presents an account of the concepts of local networkinterconnection and network component unbundling that will providepotential local exchange competitors with the knowledge of thetelecommunications market they need to assess their competitiveopportunities. It will also help policy-makers to achieve thecompetitive results that they desire. 相似文献
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SYNERGISM OF CRANBERRY PHENOLICS WITH ELLAGIC ACID AND ROSMARINIC ACID FOR ANTIMUTAGENIC AND DNA PROTECTION FUNCTIONS 总被引:2,自引:0,他引:2
Several studies have shown the antimutagenic DNA protective functions of some naturally occurring phenolic phytochemicals. Emerging research also indicates that synergistic functionality of these phytochemicals in whole foods benefits the management of many diseases. Here we have investigated the potential antimutagenic properties of cranberry phenolics, ellagic acid (EA), rosmarinic acid (RA) and their synergistic interactions on enhancing antimutagenic properties in Salmonella typhimurium tester system against mutagens sodium azide and N‐methyl‐N′‐nitro‐N‐nitrosoguanidine. Ability of these phytochemical treatments to protect oxidative damage to DNA was also investigated using the supercoiled DNA strand scission assay. Results showed that EA was most effective in inhibiting the mutations in S. typhimurium system, whereas RA and EA were equally effective in protecting the DNA from oxidative damage. Results also showed that the antimutagenic functionality of cranberry powder (CP) made from juice extracts was significantly enhanced when 30% (w/w) of phenolics in CP was substituted with RA and EA possibly because of synergistic redox modulation that can influence mutagen function. It is also suggested that the synergistic mixture of cranberry phenolics with RA could also be protecting the cell from mutations by modulating DNA repair systems. 相似文献
8.
Jochen RAIMANN Li LIU Sudhi TYAGI Nathan W. LEVIN Peter KOTANKO 《Hemodialysis international. International Symposium on Home Hemodialysis》2008,12(4):395-405
The concept of dry weight (DW) is central to dialysis therapy. The most commonly used definition of DW is the weight below which patients become hypotensive on dialysis. However, this definition is dependent on patient symptoms. A more rigorous definition of DW is the body weight at a physiological extracellular volume (ECV) state. Overhydration is an excess in ECV above that found in healthy subjects. In healthy subjects, within extremes of salt intake, ECV may vary between 280 and 340 mL/kg lean body mass. Sodium accumulation is one of the many consequences of renal failure; it results in increased water intake and an increase in ECV, and an accompanying rise in blood pressure with its clinical sequelae, most prominently cardiovascular and cerebrovascular diseases. Recently characterized endogenous digitalis‐like factors which are released in response to ECV expansion have extended this traditional picture. Efforts to reduce a positive sodium balance include dietary counseling and avoidance of iatrogenic intradialytic sodium loading, such as dialysate sodium exceeding serum levels, sodium profiling, and intravenous saline. Excess ECV is predominantly located in the interstitial compartment and must be removed during dialysis therapy by ultrafiltration. During this process, interstitial fluid redistributes to the intravascular space via uptake in the capillary bed. In addition to that mechanism, we propose that increased lymphatic flow into the venous system contributes to plasma refilling. Both clinical and technical means are used to assess the presence of DW. Continuous segmental calf bioimpedance is a promising new technology for intradialytic DW diagnosis. 相似文献
9.
ABSTRACT The purpose of this study was to determine the optimum concentrations of corn syrup required with the use of several species of homofermentative lactic acid bacteria and a commercial mixed culture inoculum in the fermentation of hydrolyzed cod gurry. Among the three homofermentative bacteria studied, Lactobacillus plantarum, Streptococcus faecium, and Pediococcus acidilactici, consistent results regarding the most rapid rate of pH reduction and the lowest final pH were obtained with L. plantarum. S. faecium was the least desirable organism on the basis of fermentation rates and the extent of pH reduction after 72 h of incubation. Corn syrup at a concentration of 4.0% (w/w) was found to be optimum for achieving a rapid and successful lactic acid fermentation of hydrolyzed cod gurry with Lactobacillus plantarum. Corn syrup at a concentration of 4.5% was found to be optimum for rapidly achieving a final pH of 4.0 with the commercial mixed inoculum Stabisil. The maltose content of corn syrup was utilized at a notably slower rate than glucose by all three microorganisms during the first 18 h of incubation. Throughout the fermentations, maltotriose was utilized significantly by only L. plantarum. 相似文献
10.
Feeding Tomatoes to Hamsters Reduces their Plasma Low-density Lipoprotein Cholesterol and Triglycerides 总被引:2,自引:0,他引:2
Hamsters were fed semipurified diets containing green or red freeze‐dried tomato powders. Compared to the control diet devoid of tomatoes, a 59% and 44% reduction low‐density lipoprotein (LDL) cholesterol was induced by both the green and red tomatoes, respectively. The corresponding reductions in very low‐density lipoproteins (VLDL) were 45% and 35% and in plasma triglyceride concentrations 47% and 31%, respectively. Plasma levels of high‐density lipoproteins (HDL) were unaffected. Fecal deoxycholic and lithocholic acid concentrations of hamsters on tomato diets were higher than those on control diets. Possible contributions of major components of green and red tomatoes to these beneficial effects are discussed. 相似文献