Intracranial chondromas

Biochemical and hormonal effects of oral calcium supplementation in premature and asphyxiated neonates during the first few days of life are described. Eight pairs of infants were matched for gestational age and one-minute Apgar score. One member of each pair served as a control and the other was given supplemental oral calcium (75 mg/kg/24 hr) beginning at 12 and ending at 72 hours of age. The supplemental infants had significantly higher serum calcium values both during the time of supplementation and for 36 hours after supplementation was stopped. The oral calcium supplements had no significant effect on serum concentrations of phosphate, magnesium, 25-hydroxy-vitamin D3, or parathyroid hormone, The incidence of hypocalcemia after 12 hours of age was 0 in eight supplemented infants and three in eight control infants. In patients at risk for hypocalcemia, prospective use of oral calcium supplements during the period when there is inadequate calcium intake from feedings may prevent hypocalcemia, appears to be without deleterious effect on measurable chemical and hormonal factors important in calcium homeostasis, and results in maintenance of higher serum calcium levels after supplementation has been discontinued.     

Hemicellulose Removal from Hardwood Chips in the Pre-Hydrolysis Step of the Kraft-Based Dissolving Pulp Production Process

Abstract

A pre-hydrolysis step to remove hemicelluloses from mixed hardwood chips consisting of maple, aspen, and birch with a ratio of 7:2:1 has been carried out. The effects of parameters on the pre-hydrolysis such as time, temperature, acetic acid addition, and raw material species, were determined. Different sugars, acetic acid, and furfural formation in the pre-hydrolysis liquor were quantified. The results showed that the pre-hydrolysis is a dynamic process, in which the removal of hemicelluloses increased with time while the conversion of extracted hemicelluloses to monosaccharides due to acid hydrolysis increased and part of the xylose was converted to furfural. The maximum temperature was the most critical parameter for hemicelluloses extraction and conversion, and a temperature of 170°C was the optimum for hemicelluloses extraction with relatively low conversion of xylose to furfural. About 11% of the xylan (in both monomeric and oligomeric forms) was removed at 170°C. Due to the presence of a high amount of xylan, birch produced the highest amount of xylose, followed by maple, and then aspen.     

Role of Gasoline Specifications in the Control of Environmental Pollution

Abstract

Gasoline is a mixture of about 100 hydrocarbon compounds. Molecular carbon numbers range from C6–C12 and evaporating between ambient temperatures to about 220°C. Gasoline is used in spark ignition engines (cars and motorcycles). The grades and types of gasoline are usually defined in terms of octane numbers. The specifications of gasoline is based mainly on physical properties, which can be related to performance such as volatility and octane number. Chemical components such as oxygen, sulfur, lead, and benzene are also significant. The present trend is to incorporate generic fractions such as aromatics and olefinics in the specifications. How these parameters (specifications) relate to the various fuel requirements and subsequently affect the environment is described in this article.     

Agile practices and performance: Examining the role of psychological empowerment

This study draws on the literature on psychological empowerment to conceptualize agile practices as a source of intrinsic motivation that enables the agile teams to deliver innovative outcomes. Then, drawing on the resource based view of innovative projects, the innovative behaviour of agile teams is cast as a project capability that affects project performance. To test this original conceptualization, data was collected to find support for the hypothesized relationships between agile practices, psychological empowerment, innovative behaviour and project performance. The statistical results showed that the agile practices of team autonomy and agile communication contributed to psychological empowerment that led to the innovative behaviour of agile teams. The innovative behaviour also affected project performance. The empirical validation of agile practices as a source of empowerment and motivation for agile teams is a new finding in the literature which has strong implications for both the theory and practice.