Influence of niobium on stacking-fault energy of all-austenite stainless steels

The effects of niobium addition on a completely austenitic stainless steel matrix consisting of Fe-15%Cr-15%Ni, with about 0, 0.5, 1 and 2% niobium, were studied by determination of stacking fault energies by means of X-ray diffraction analysis. A strong influence of niobium on stacking-fault energies was found, whose behaviour can be explained as being due to decrease in the electron/atom ratio and increase in the L. Pauling electron vacancy number of austenitic Fe-Cr-Ni matrix brought on by niobium.     

Monitoring the oxidative modification of lipoprotein(a) by capillary zone electrophoresis

Lipoprotein(a) [Lp(a)] is a recognized risk factor for atherosclerotic cardiovascular disease. It is made of a lipoprotein particle containing apoB100 linked by a single disulfide bridge to apolipoprotein(a), a glycosylated protein with a variable mass. Some authors suggest that oxidative modification could explain the contribution of Lp(a) in the development of atheromatous lesions in a comparable way to low‐density lipoproteins (LDL). Recently, the use of capillary electrophoresis to measure the variations in the relative electrophoretic mobility (REM) of LDL subjected to copper oxidation has been proposed. The aim of this work is to employ this method also to monitor the copper‐induced oxidative modification of Lp(a). Migration of Lp(a) was monitored by absorption at 200 nm in a 50 mmol/L tricine, 100 mmol/L methylglucamine, pH 9.7 run buffer. Contrary to the conventional slab gel methods, our procedure provides a rapid and reproducible means to measure the electrophoretic mobility of Lp(a) (migration time <10 min with a CV% <0.5).     

Preface

Literature on the health aspects of the presence of heavy metals in water and wastewaters is reviewed and quality standards, criteria and legislation promulgated by the World Health Organisation, European Economic Community, U.S. Environmental Protection Agency and Government of the U.S.S.R. are assessed and compared. It is evident from the literature that standards applied difer according to the projected water use and that although standards for potable water are generally based on human health criteria, other factors including available technology and economics may be limiting. Emphasis has been placed on the protection of raw water quality as a result of the limited ability of potable water treatment processes to remove certain heavy metals.It is apparent that limitations on heavy metals in discharges from the chlor-alkali and cadmium salts and pigments industries are more stringen in the United States than in the European Economic Community.It is concluded that the finite availability of unpolluted freshwater will result in greater water re-use and that appropriate standards are required to protect potable supply, raw water and agricultural land from contamination by heavy metals.     

Effects of cyanide on peanut lipoxygenase

Acidic and alkaline lipoxygenase isozymes were separated and assayed for activity while incubated in the presence of various concentrations of cyanide. Inhibition due to cyanide per se was not found. Instead, cyanide caused an increase in pH, which decreased the activity of the acidic isozyme to a rate corresponding to the same pH on the activity curve for the cyanide-free reaction.     

Mesoporous catalysts for the synthesis of clean diesel fuels by oligomerisation of olefins

Si/Al MCM-41 type mesoporous compounds, as such or containing small amounts of metal (Ni, Rh or Pt), were investigated in the synthesis of clean diesel fuels by oligomerisation of orphan olefin streams. Very good catalytic performances were obtained with C₄ and C₅ olefins, while almost no conversion occurred with ethylene. The activity increased with increasing reaction pressure, temperature and contact time, while high Si/Al ratios had a negative effect on both activity and catalyst stability. The presence of small amount of metal inside the mesoporous structure did not significantly modify the catalytic activity, although specific effects were detected for each element. Since the evaluation of the cetane number by H-NMR gave rise to values about 20% lower than the actual value, a new and more complex algorithm is proposed to calculate the cetane number. Using the proposed algorithm, a good correlation index was found between calculated and motor values for pure compounds. Further study is necessary to move from pure compounds to experimental mixtures.     

Cobalt-related asthma: clinical and immunological aspects

Several clinical and experimental findings point to cobalt as the only sensitizer and causal agent of hard metal asthma. The clinical features have been clearly defined by bronchial provocation tests, with a prevalence of late phase responses. Epidemiology is still insufficient to configure prevalence and incidence rates for cobalt asthma. IgE and IgG antibodies with cobalt specificity have been demonstrated, but T-lymphocytes and eosinophyls involvement seem to be important in the mechanism of an allergic inflammation in the airways. Such an immunological pathogenesis links cobalt asthma with other manifestation of hard metal disease.     

Interpolatory quadrature rules and error rate of digital communication systems

A simple numerical technique is proposed for the construction of the estimate of integrals which represent the average error probability of many digital communication systems. Since these integrals are expressed as the expectation of some function of a random variable, their evaluation can be based on the knowledge of a number of moments of the variable. This is investigated from the viewpoint of discussing an algorithm based on interpolatory quadrature formulas which have equally spaced nodes. An example shows the satisfactory performance of the proposed approach.     

Lipolysis in castor seeds: A reinvestigation of the neutral lipase

Attempts to study the neutral lipase reported in germinating castor seeds and to compare this enzyme to the acid lipase of dormant seeds were unsuccessful because of the inability to repeat the work described earlier (1). Activity of the proposed neutral lipase could not be detected, nor could appearance of the enzyme be hastened or affected by treating the germinating seeds with gibberellic acid or Actinomycin-D. Possible explanations for the discrepancy between these findings and the early report are presented. So. Utiliz. Res. Dev. Div., ARS, USDA.     

Audio-biofeedback for balance improvement: an accelerometry-based system

This paper introduces a prototype audio-biofeedback system for balance improvement through the sonification using trunk kinematic information. In tests of this system, normal healthy subjects performed several trials in which they stood quietly in three sensory conditions while wearing an accelerometric sensory unit and headphones. The audio-biofeedback system converted in real-time the two-dimensional horizontal trunk accelerations into a stereo sound by modulating its frequency, level, and left/right balance. Preliminary results showed that subjects improved balance using this audio-biofeedback system and that this improvement was greater the more that balance was challenged by absent or unreliable sensory cues. In addition, high correlations were found between the center of pressure displacement and trunk acceleration, suggesting accelerometers may be useful for quantifying standing balance.