Studies on BiCoO3 and BiCo1−xFexO3

BiCoO₃ and BiCo_1?xFe_xO₃ (x ≤ 0.7) prepared at atmospheric pressure are found to possess a cubic structure probably involving the Bi₁₂O₃₆ network. BiCoO₃ is paramagnetic above 100 K, with a negative paramagnetic Curie temperature. BiCo_1?xFe_xO₃ (x = 0.5 or 0.7) is ferromagnetic with T_c ≈ 600K.     

Kinetics of Domain Growth in Ordered Ni4Mo

The kinetics of domain growth in Ni4Mo in the temperature range of 600 to 850 °C were investigated using transmission electron microscopy. It was found that domain growth in Ni₄Mo is analogous to metallurgical grain growth and can be described by the expressionD ⁿ =kt, whereD is the average domain size, t is the aging time, k is a constant, and the exponent n is the reciprocal of the slope of the log D vs log t plot. The value of n changed with temperature from 2.0 at 850 and 800 °C to 2.9 at 700 and 600 °C. This change was explained in terms of relative domain orientation effects. The activation energy for domain growth was obtained as 69 Kcal/mole (2.9 × 105 Joules/mole) in the temperature range of 800 to 850 °C and as 92 Kcal/mole (3.85 x 105 Joules/mole) in the temperature range of 600 to 700 °C, which on comparison with available diffusion data established that the growth process was interface-controlled at the higher temperatures and bulk diffusion-controlled at the lower temperatures.     

Psychophysical estimation of speed discrimination. II. Aging effects

We studied the effects of aging on a speed discrimination task using a pair of first-order drifting luminance gratings. Two reference speeds of 2 and 8 deg/s were presented at stimulus durations of 500 ms and 1000 ms. The choice of stimulus parameters, etc., was determined in preliminary experiments and described in Part I. Thresholds were estimated using a two-alternative-forced-choice staircase methodology. Data were collected from 16 younger subjects (mean age 24 years) and 17 older subjects (mean age 71 years). Results showed that thresholds for speed discrimination were higher for the older age group. This was especially true at stimulus duration of 500 ms for both slower and faster speeds. This could be attributed to differences in temporal integration of speed with age. Visual acuity and contrast sensitivity were not statistically observed to mediate age differences in the speed discrimination thresholds. Gender differences were observed in the older age group, with older women having higher thresholds.     

Antibacterial effect of caprylic acid and monocaprylin on major bacterial mastitis pathogens

Bovine mastitis is the most significant economic drain on the worldwide dairy industry. Concerns regarding poor cure rates, emergence of bacterial resistance, and residues in milk necessitate development of alternative therapeutic approaches to antibiotics for treatment of mastitis. A variety of free fatty acids and their monoglycerides have been reported to exert antimicrobial activity against a wide range of microorganisms. The objective of our study was to examine the efficacy of caprylic acid, a short-chain fatty acid, and its monoglyceride, monocaprylin, to inactivate common mastitis pathogens, including Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Staphylococcus aureus, and Escherichia coli. Milk samples containing 50 mM or 100 mM caprylic acid, and 25 mM or 50 mM monocaprylin were inoculated separately with a 3-isolate mixture of each of the 5 pathogens, and incubated at 39°C. Populations of surviving bacteria were determined at 0 min, 1 min, 6 h, 12 h, and 24 h of incubation. Both caprylic acid and monocaprylin reduced all 5 pathogens by >5.0 log cfu/mL after 6 h of incubation. Among the bacterial species tested, Strep. agalactiae, Strep. dysgalactiae, and Strep. uberis were most sensitive, and E. coli was most tolerant to caprylic acid and monocaprylin. Results of this study indicate that caprylic acid and monocaprylin should be evaluated as alternatives or adjuncts to antibiotics as intra-mammary infusion to treat bovine mastitis.     

Low-cycle fatigue studies on nuclear reactor Zircaloy-2 fuel tubes at room temperature, 300 and 350°C

Constant amplitude strain controlled fatigue tests were conducted on the Zircaloy-2 fuel tubes at room temperature, 300 and 350°C on the modified Moore type, four-point-loaded, deflection-controlled, rotating bending fatigue testing machine. The relationship between the plastic strain range, Δ?_p and the number of cyles to failure, N_f was found to be of a simple power law of the form N^β_f · Δ?_p = constant, at all the test temperatures. Strain-hardening coefficients were determined from monotonic tension tests at these temperatures and it was concluded that the material is more or less in a cyclically stable condition.     

Effect of External Viscous Load on Head Movement

Quantitative measurements of horizontal head rotation were obtained from normal human subjects intending to make "time optimal" trajectories between targets. By mounting large, lightweight vanes on the head, viscous damping B, up to 15 times normal could be added to the usual mechanical load of the head.     

Optimum diversity combiner based multiuser detection fortime-dispersive Rician fading CDMA channels

Multiuser detection for asynchronous code division multiple access (CDMA) data transmission over the time-dispersive two-path Rician fading channel is considered. The multiuser maximum likelihood sequence detector (MLSD) is derived, and an equivalence of the fading channel to an asynchronous Gaussian intersymbol interference (AGISI) CDMA channel is established. However, the MLSD is found to be implementationally infeasible and this motivates the derivation of the optimum linear detector with near/far resistance as the performance criterion. The optimally near/far resistant linear time-invariant K-user detector is shown to consist of a cascade of a 2 K input/K output linear multiuser diversity combining filter followed by a K input/K output decorrelator that is designed for the equivalent AGISI/CDMA channel. This detector solves the near/far problem and also supports significantly higher bandwidth efficiencies for CDMA communication over the fading channel than does the conventional near/far limited single-user diversity combiner. The performance penalties incurred by multiuser detectors designed for the Gaussian channel when used over the Rician fading channel are also analytically characterized. It is shown that these penalties can be significant, making the case for the use of multiuser detectors optimized for this fading channel, particularly the optimum linear detector due to its relative implementational simplicity     

Hypoglycaemic and Hypolipidaemic Effects of Withania somnifera Root and Leaf Extracts on Alloxan-Induced Diabetic Rats

Withania somnifera is an important medicinal plant, which is used in traditional medicine to cure many diseases. Flavonoids were determined in the extracts of W. somnifera root (WSREt) and leaf (WSLEt). The amounts of total flavonoids found in WSREt and WSLEt were 530 and 520 mg/100 g dry weight (DW), respectively. Hypoglycaemic and hypolipidaemic effects of WSREt and WSLEt were also investigated in alloxan-induced diabetic rats. WSREt and WSLEt and the standard drug glibenclamide were orally administered daily to diabetic rats for eight weeks. After the treatment period, urine sugar, blood glucose, haemoglobin (Hb), glycosylated haemoglobin (HbA1C), liver glycogen, serum and tissues lipids, serum and tissues proteins, liver glucose-6-phosphatase (G6P) and serum enzymes like aspartate transaminase (AST), alanine transaminase (ALT), acid phosphatase (ACP) and alkaline phosphatase (ALP) levels were determined. The levels of urine sugar, blood glucose, HbA1C, G6P, AST, ALT, ACP, ALP, serum lipids except high density lipoprotein-bound cholesterol (HDL-c) and tissues like liver, kidney and heart lipids were significantly (p < 0.05) increased, however Hb, total protein, albumin, albumin:globulin (A:G) ratio, tissues protein and glycogen were significantly (p < 0.05) decreased in alloxan-induced diabetic rats. Treatment of the diabetic rats with WSREt, WSLEt and glibenclamide restored the changes of the above parameters to their normal level after eight weeks of treatment, indicating that WSREt and WSLEt possess hypoglycaemic and hypolipidaemic activities in alloxan-induced diabetes mellitus (DM) rats.