Examinations of Dimethyl Sulfoxide-Phase Equilibrium Acidities of Selected Polycyclic Aromatic Compounds

Comparisons of dimethyl sulibxide (DMSO)-phase pK _a's (in parentheses) for 10-cyano-9-methoxymethy-lanthracene (17.35), 10-cyano-9-phenoxymethylanthracene (14.9), 9-cyanomethoxymethylanthracene (20.4), and (α-methoxy) phenylacetonitrile (23.0) with literature DMSO-phase pK _a's for 9-methylanth-racene, 9-methoxymethylanthracene, 9-phenoxymethylanthracene, 9-cyanomethylanthracene, 10-cyano-9-methylanthracene, and phenylacetonitrile (31.1, 30.6, 30.2, 19.7, 20.0, and 21.9, respectively), indicate that: (a) α-methoxy and α-phenoxy substituents acidify 10-cyano-9-methylanthracene; (b) an α-methoxy moiety deacidifies 9-cyanomethylanthracene and phenylacetonitrile; and (c) 10-cyano substituents acidify 9-methylanthracene, 9-methoxymethylanthracene, and 9-phenoxymethylanthracene by 11.1, 13.25, and 15.3 pK _a units, respectively. These data are indicative of steric inhibition of resonance, resonance saturation, and effects due to cross conjugation, in carbanions derived from variously substituted 9-methylanthracenes. DMSO-phase pK _a for phenalene (18.2) and benzanthrene (20.2) have also been determined. In DMSO, phenalene is therefore 4.4 pK units more acidic than its isomeric analogue fluorene (22.6), while benzanthrene is 0.5 pK units less acidic than its isomeric analogue 1,2-benzofluorene (19.7). Specific solvation of the allylic-like phenalenide anion is a likely reason for its enhanced acidity, relative to benzanthrene.     

Aluminum: Approaching the new millennium

During the past 100 years, aluminum has developed into a staple of the manufacturing industry. The industry has undergone successive revolutions in consumption, smelter location, and pricing. Now, it faces more change as products mature, new markets struggle to develop, and technology advances further.     

Anger as a predictor of aggression among incarcerated adolescents.

This study examined the validity of trait anger as a predictor of aggressive behavior among juvenile offenders. Two standard self-report anger scales were administered to 65 recently incarcerated male adolescents. These youths were followed prospectively for physical and verbal aggression during 3 months of subsequent incarceration. Anger scores were not correlated with participant history of violent offending or staff ratings of anger. However, anger scores from both instruments were predictive of subsequent physical and verbal aggression. For example, the Trait Anger scale successfully classified 66% of juvenile offenders into high and low aggressive groups; receiver operating characteristic analysis obtained an effect size of .72. These results support the predictive validity of self-reported anger in identifying juvenile offenders at risk for institutional aggression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Software Assumptions Lead to Preventable Errors

Undocumented assumptions are often the cause of serious software system failure. Thus, to reduce such failures, developers must become better at discovering and documenting their assumptions. In this article, we focus on common categories of assumptions in software, discuss methods for recognizing when developers are making them, and recommend techniques for documenting them.     

An air-stable biomimetic Langmuir–Blodgett bilayer

The long-chain amphiphiles in biomembranes have their hydrophilic headgroups oriented outwards towards the aqueous environment, and their long aliphatic chains innermost. In Langmuir–Blodgett (LB) films the hydrophobic chains are normally outermost. LB films of long-chain derivatives can be prepared under water with the headgroups outermost and are stable while kept there, but the act of removing them from the aqueous environment removes the top monolayer. We demonstrate an adaptation of the LB technique which is appropriate for the preparation of biocompatible surfaces. It produces essentially bilayer films of long-chain derivatives on standard substrates with a hydrophilic outer surface. The films are stable in air. The films show large contact angle hysteresis with water, but the receding angle is in most cases less than 10°. The films can be immersed and withdrawn from water many times before wettability or average thickness change significantly. Compared to previously reported air-stable surfaces with a structure mimicking biological membranes, the substrate for the present surface is experimentally more convenient.     

AN IMPROVED VOLUMENOMETER*

A volumcnometer of improved design has been developed for measuring the solid volumes of specimens varying in size up to that of standard refractory bricks. The chief feature of the new design is the use of a closed-cistern, altitude-type mercurial barometer to replace the simple manometer previously used. The barometer is de signed for use in a constant temperature room (21.1°C.) where the acceleration of gravity is 980.1 cm. per sec.². Under these conditions, pressure readings are auto matically corrected to standard conditions. A vernier permits rapid readings to 0.1 mm. of mercury.     

Smoking and Parkinson''s disease: a dose-response relationship

BACKGROUND: Previous studies questioned the link between early childhood anemia and detrimental child development. OBJECTIVE: A population-based study was conducted to examine the association between early childhood anemia and mild or moderate metal retardation at 10 y of age. DESIGN: The present study linked early childhood nutrition data collected by the Special Supplemental Program for Women, Infants, and Children (WIC) and school records. Hemoglobin values were used to determine the relation between anemia in early life and children's placement in special education classes for mild or moderate mental retardation. Subjects were all participants in the WIC program. A computer program was used to link data from birth, WIC, and school records. RESULTS: Logistic regression showed an increased likelihood of mild or moderate mental retardation associated with anemia, independent of birth weight, maternal education, sex, race-ethnicity, the mother's age, or the child's age at entry into the WIC program. CONCLUSION: These findings support the proposition that efforts to prevent mild and moderate mental retardation should include providing children with adequate nutrition during early childhood.     

Study of Morphological Defects on Dual-Band HgCdTe on CdZnTe

HgCdTe dual-band epitaxial layers on lattice-matched CdZnTe substrates often have morphological defects. These defects, unlike normal void and microvoid defects, do not contain a polycrystalline core and, therefore, do not offer a good contrast for observation using optical and electron microscopes. This paper reports a way of identifying these defects by using a Nomarski optical microscopy image overlay on focused ion beam microscopy images for preparation of thin cross-sectional foils of these defects. Transmission electron microscopy was used to study the defect cross-sections to identify the origin and evolution of the morphological defects and their effect on the epitaxial layer. This paper reports cross-sectional analysis of four morphological defects of different shape and size.