Superfecundation identified by HLA, protein, and VNTR DNA polymorphisms

Parentage analysis has revealed a high probability that a man accused of paternity is the biological father of a male child. The child in this study, however, was the twin of a female child who could not have been fathered by the accused man. The mother of the children subsequently accused a second, unrelated man, who was excluded from paternity of the boy, but was very probably the biological father of the girl.     

Processes underlying divergent thinking and problem solving.

A battery of problem-solving and divergent-thinking tasks was administered to 91 5th graders from a middle-class background. The purpose was to attempt identification of a factor that could be labeled "problem solving" and be distinct from divergent-thinking factors. In exploratory factor analyses, principal axis, alpha, and maximum-likelihood factor procedures with orthogonal and oblique rotations were computed. The 3-factor solutions across all factor methods and rotations were consistent. In addition to a major ideational fluency factor and a small school achievement factor, a factor consisting of tasks requiring Ss to analyze given problem conditions and sequence steps to achieve a stated goal was identified. This factor accounted for 20–30% of the total variance and was labeled a problem-solving factor. Results are discussed in terms of possible psychological processes underlying divergent thinking and problem solving. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design and construction of a hybrid immunoglobulin domain with properties of both heavy and light chain variable regions

The complementarity-determining regions (CDRs) of a human kappa light chain were replaced with CDRs from a murine gamma-1 heavy chain and, by use of molecular modeling, key heavy chain framework residues were identified and thus included to preserve the native conformation of the heavy chain CDRs. Co-expression of this hybrid human kappa chain (V[HB]C[L]) with a human kappa chain counterpart (V[L]C[L], engineered to contain murine light chain CDRs) resulted in the secretion of high levels of a heterodimeric protein (V[HB]C[L]::V[L]C[L]) termed 'kappabody'. This protein also had equivalent affinity for antigen as the Fab' of the parent murine IgG1. High-level secretion was also observed for the hybrid chain as homodimers (V[HB]C[L]::V[HB]C[L]), which is not observed for chimeric chains consisting of a heavy chain variable region and light chain constant region, i.e. V[H]C[L] homodimers or single chains are not secreted. This indicates that regions within the variable domain, required for secretion of light chains, reside outside of the hypervariable regions (CDRs) and that the heavy chain CDRs and supporting residues do not prevent secretion. These results demonstrate the possibility of designing small, single- domain molecules possessing a given binding activity which may be secreted at high levels from mammalian cells.      

Oxidative conversion as a means of detecting precursors to perfluoroalkyl acids in urban runoff

A new method was developed to quantify concentrations of difficult-to-measure and unidentified precursors of perfluoroalkyl carboxylic (PFCA) and sulfonic (PFSA) acids in urban runoff. Samples were exposed to hydroxyl radicals generated by thermolysis of persulfate under basic pH conditions and perfluoroalkyl acid (PFAA) precursors were transformed to PFCAs of related perfluorinated chain length. By comparing PFCA concentrations before and after oxidation, the concentrations of total PFAA precursors were inferred. Analysis of 33 urban runoff samples collected from locations around the San Francisco Bay, CA indicated that PFOS (2.6-26 ng/L), PFOA (2.1-16 ng/L), and PFHxA (0.9-9.7 ng/L) were the predominant perfluorinated compounds detected prior to sample treatment. Following oxidative treatment, the total concentrations of PFCAs with 5-12 membered perfluoroalkyl chains increased by a median of 69%, or between 2.8 and 56 ng/L. Precursors that produced PFHxA and PFPeA upon oxidation were more prevalent in runoff samples than those that produced PFOA, despite lower concentrations of their corresponding perfluorinated acids prior to oxidation. Direct measurements of several common precursors to PFOS and PFOA (e.g., perfluorooctanesulfonamide and 8:2 fluorotelomer sulfonate) accounted for less than 25% of the observed increase in PFOA, which increased by a median value of 37%. Exposure of urban runoff to sunlight, advanced oxidation processes, or microbes could result in modest, but measurable, increases in concentrations of PFCAs and PFSAs.     

Characterization of acetylene terminated sulfone (ATS) resin. II. Thermal analysis of the resin

The kinetics and thermodynamics of the cure and post-cure reactions of an acetylene terminated sulfone (ATS) resin mixture and pure fractions from that mixture were studied using differential scanning calorimetry. Thermal stabilities were measured by programmed thermogravimetry under helium, and oxidative stabilities using isothermal thermogravimetry in air. Microstructural changes accompanying the cure reaction were identified using infrared spectroscopy. Early products of thermal degradation were trapped for identification and quantitative analysis using the technique of sub-ambient thermal volatilization analysis. We found that glass transition temperatures increase with crosslink density in the resin, that oxygen is able to copolymerize or couple with the polyenes to produce peroxides or hydroperoxides (respectively) which subsequently decompose to form terminal alcohols on the polyene, that weight loss in air at 600°F is an oxidative process that is insensitive to resin crosslink density, and that sulfone functionality constitutes the thermal weak link in the ATS resin system.     

Microcellular foams from some high-performance composites

High-temperature composites were successfully prepared from aminated polysulfone, polyphenylsulfone, and a rod-like polymer polybenzimidazole (PBI). The single glass transition temperature T_g and the absence of evidence for phase separation in scanning electron microscopy suggested that these systems formed so-called ‘molecular composites’. The enhanced miscibility between the polymer pairs was probably due to hydrogen bonding interactions. Compared with the matrix polymers themselves, these composites have improved values of T_g and thermal stability due to a synergistic effect upon incorporation of polybenzimidazole into the polymer matrices. Microcellular foams were successfully prepared from these composites. The foaming behavior and morphologies of the resulting composite foams were much more complicated than those of the pure polymers. In particular, they had unusual bimodal cell size distributions, and some open or partially open-cell structures.