A survey of Toeplitz and related matrices

Properties and definitions of Toeplitz and related matrices scattered throughout the literature are collected together, and presented in a unified form. Toeplitz, ortho-symmetric, Hankel, persymmetric, circulant and centrosymmetric matrices are covered. Inversion algorithms for general, special and block Toeplitz matrices are outlined. A considerable number of references is given     

Studies on Processing of an Alnico Scrap

Abstract

This paper presents the results of research and development work on processing of alnico scrap, a secondary resource of nickel and cobalt, generated during the manufacturing of alnico magnets. The scrap contains 8-10% nickel, 10-12% cobalt, 32-50% of iron, 8-10% aluminium, 2% copper and remaining silica. Various processes such as acid leaching, aqueous chlorine leaching, salt roasting and cupric chloride leaching were studied in detail. Of these cupric chloride leaching was found to be most effective with respect to recovery and purity. It has been possible to obtain pure nickel and cobalt salts by cupric chloride leaching of the scrap, solvent extraction and precipitation of the salts. The overall recovery by the above process was almost 99%.     

Effects of Gamma Irradiation Combined with Hot Dipping on Quality of "Kensington Pride" Mangoes

Market mature “Kensington pride” mangoes, dipped in a benomyl solution (500 ppm a.i.) or in hot water at 527deg;C for 5 min, were irradiated in air at intervals of up to 42 hr after dipping at doses up to 1000 Gray (Gy). Irradiation retarded skin coloration, with a proportion of those dosed at 600 Gy and 10000Gy not coloring normally, and some developing undesirable skin bronzing at 1000 Gy. Irradiation did not affect flesh softening. Hot dip treatments accelerated skin coloration and the longer the interval between dipping and irradiation the more this was evident. Irradiation delayed ripe fruit rot in mangoes. A hot benomyl dip in combination with irradiation between 75 Gy and 600 Gy preserved fruit quality with negligible adverse phytotoxic Effects.     

Effect of Manganese Ions on the Fermentative Activity of Frozen-Thawed Lactobacilli

The lactic acid fermentation of monoand disaccharides by frozenthawed Lactobacillus plantarum in modified All Purpose Tween (MAPT) broth was stimulated by manganese ions (Mn₂₊). Beaker sausage formulated with either dextrose or sucrose attained pH 5.0 faster with Mn₂₊. L. plantarum frozen stored for 2 wk was stimulated by Mn₂₊ more than the same culture frozen stored for 2 yr. The fermentation period of sucrose with Mn₂₊ was shorter than that of dextrose. CaC12 (as a substitute for NaCI) and Mn₂₊ reduced the fermentation period more than NaCI. The fermentation of dextrose by L. lactis was reduced the most by Mn₂₊, followed by L. casei subspecies casei, L. plantarum and L. casei subsp. alactosus. Calcium ions were not efficient in reducing the fermentation time of dextrose by lactobacilli in summer sausage.     

Sensory Characteristics of Sucralose and other High Intensity Sweeteners

The sensory characteristics of the high potency sweetener sucralose were studied relative to sucrose, aspartame, saccharin, and acesulfame-K in a simple aqueous system. Trained panelists provided sweetness intensity estimates for each sweetener at six concentration steps using magnitude estimation. Taste profiles were obtained using category scaling procedures. Results indicated that (a) sucralose, aspartame, and sucrose had similar taste properties, (b) the psychophysical sweetness function of sucralose was similar to the other sweeteners studied, and (c) sweetness potencies of all sweeteners were concentration dependent with sucralose having the highest potency values ranging from 400–700 times the sweetness of sucrose on a weight basis.     

PAMELA sub-detectors capability in identifying nuclei: Status of art and perspectives

After almost three years in orbit, the statistic collected by PAMELA detector for what concern nuclei events from cosmic rays is sufficiently relevant to allow a systematic study of such a component. For this scope charge reconstruction from Time-of-Flight system, calorimeter and magnetic spectrometer is used, with different combinations, in order to cover the widest range of inspection in energy and atomic number permitted by the characteristics of the detector. Some results for performances, goals and limits from the different sub-detectors will be presented.     

Isolation and biological characterization of a basic phospholipase A₂ from <i>Bothrops jararacussu</i> snake venom

A phospholipase A₂ has been isolated from Bothrops jararacussu venom from snakes that inhabit the northeast region of Argentina. The present study describes in vivo and in vitro biological activities of phospholipase A₂ from B. jararacussu as well as isolation details of its. Venom was obtained by milking of adult snakes which were housing in wood reptile cages of varying dimensions in heated (20–30ºC) rooms. Snakes received a weekly diet of mice and water was available ad libitum for drinking and soaking. The enzyme was purified by gel filtration on a Sephadex G-75 column followed by ion exchange chromatography on a SP-Sephadex C25 column. The major peak belonging to proteins was retained in the cation exchanger and then eluted using a concentration gradient of KCl that exhibited phospholipase activity.
This basic PLA₂ consists of a single polypeptide chain with a molecular mass of 15.6 kDa. It had a high indirect hemolytic activity and produced a significant paw edema reaction in mice. The enzyme showed a low lethality (LD₅₀ 148.6 µg) when was administered i.p. but exhibited elevated myotoxic effects in vivo by increasing plasma CK activity of injected mice, corroborated results by the histological observations of samples of gastrocnemius muscle. Myonecrosis is the result of intense destruction of muscular fibers that involves local infiltration of inflammatory cells and leads to the highest peak of CK level just after 1 hour mice injection. Moreover, the isolated enzyme showed anticoagulant activity, evaluated on sheep platelet-poor plasma which recalcification time was prolonged after incubation with the isolated phospholipase A₂ . These findings showed that this phospholipase, isolated by only two simple chromatographic steps, possesses high edematogenic and myotoxic activities. However, despite the low lethal activity, this enzyme would contribute markedly to the pathophysiology of the bothropic envenomation.