Unfair Treatment, Discrimination, and Ambulatory Blood Pressure in Black and White Adolescents.

The authors tested the hypotheses that unfair treatment and its attribution to race, physical appearance, and peer group were related to elevated ambulatory blood pressure (ABP). During 2 school days, 207 Black and White adolescents wore an ABP monitor and answered questions about mood, posture, location, and activity level at the time of the ABP assessment. At a separate session, in-clinic resting blood pressure and perceptions of unfair treatment were measured. Multilevel mixed models showed that unfair treatment and its attribution to race were not associated with ABP. However, adolescents who indicated that the primary reason for unfair treatment was their physical appearance had elevated ABP. Feeling unfairly treated because of physical appearance may impact blood pressure uniquely during the adolescent transition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scheduling Independent Multiprocessor Tasks

Abstract. We study the problem of scheduling a set of n independent multiprocessor tasks with prespecified processor allocations on a fixed number of processors. We propose a linear time algorithm that finds a schedule of minimum makespan in the preemptive model, and a linear time approximation algorithm that finds a schedule of makespan within a factor of (1+\eps) of optimal in the non-preemptive model. We extend our results by obtaining a polynomial time approximation scheme for the parallel processors variant of the multiprocessor task model.     

Purification and crystallization of benzoylformate decarboxylase

A new large-scale purification method for benzoylformate decarboxylase from Pseudomonas putida has allowed us to undertake an X-ray crystallographic study of the enzyme. The previously observed instability of the enzyme was overcome by addition of 100 microM thiamine pyrophosphate to buffers used in the purification. The final enzyme preparation was more than 97% pure, as determined by denaturing gel electrophoresis and densitometry. The mobility of the enzyme on a gel filtration column indicates that it is a tetramer of 57-kDa subunits. Large, single crystals of benzoylformate decarboxylase were grown from solutions of buffered polyethylene glycol 400, pH 8.5. The crystals diffract to beyond 1.6 A resolution and are stable for days to X-ray radiation. Analysis of X-ray data from the crystals, along with the newly determined quaternary structure, identifies the space group as I222. The unit cell dimensions are a = 82 A, b = 97 A, c = 138 A. An average Vm value for the crystals is consistent with one subunit per asymmetric unit. The subunits of the tetramer must be arranged with tetrahedral 222 symmetry.     

Maternal intervention in toddler peer conflict: The socialization of principles of justice.

The focus of this research was mothers' interventions in object conflicts between toddler peers. Maternal consistency in endorsing principles of ownership and possession was evaluated. 32 20- or 30-mo-old children were observed playing with same-aged, same-sex peers for 18 40-min sessions. Mothers of both children were present and free to respond to their children but were asked not to organize or direct the children's play. We found that mothers frequently intervened and that they overwhelmingly favored the other child; however, mothers of boys supported their own children more than mothers of girls. Additionally, mothers were not consistent in endorsing rights of either ownership or possession and thus did not provide coherent information for the children's acquisition of principles of entitlement. Rather, mothers' interventions appeared to be aimed at restoring harmony between the children by urging their own children to yield to their peers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanical relaxation processes in polyacrylonitrile polymers and copolymers

The dynamic mechanical properties of molded and cast polyacrylonitrile and copolymers have been measured by an automatic Rheovibron. The transitions are described for the amorphous, “paracrystalline,” and crystalline phases. Based upon a number of polymer theories of multiple phases in polymeric systems, the transitions have been assigned to specific polymer motions. Three transitions are defined for the alpha transition region. The mechanical response is compared to x-ray diffraction and infrared to ascertain the transition assignments in decreasing order beginning with the highest temperature transition as (1) the main transition for the amorphous phase (T₁), (2) dipole–dipole interaction which is related to the “paracrystalline phase” (T₂), and (3) secondary transition for the amorphous phase (T₃).     

Procainamide-induced agranulocytosis differs serologically and clinically from procainamide-induced lupus

Agranulocytosis is a well recognized but uncommon complication of procainamide (PA) therapy, whereas a lupus-like syndrome occurs in approximately 20% of patients treated chronically with PA. In order to gain insight into the immunopathogenic relationships among these conditions, we compared the humoral immune abnormalities in these patient groups as well as in asymptomatic PA-treated patients. A relatively uniform profile of IgM but not IgG autoantibody reactivity with a set of chromatin-related antigens was observed in eight elderly men who developed agranulocytosis after treatment with PA. In contrast PA-induced lupus patients had predominant reactivity with [(H2A-H2B)-DNA] in both IgM and IgG classes. Five of eight patients with agranulocytosis had elevated levels of neutrophil-reactive IgG which appeared to be due to immune complexes based on Fc gamma receptor blocking studies. However, 12 of 15 patients with PA-induced lupus, none of whom had neutropenia, had similar levels of neutrophil-reactive IgG, suggesting that this reactivity was not causally related to agranulocytosis. Agranulocytosis developed after less than 3 months treatment with PA in six of eight patients. This time course was similar to that seen in 77 PA-induced agranulocytosis patients reported in the literature plus 127 patients reported to the U.S. Food and Drug Administration in whom 90% developed agranulocytosis within 3 months of starting PA. In contrast, the mode duration of treatment with PA before lupus-like symptoms develop is 10-12 months. These findings, together with the different profiles of autoantibodies and clinical presentations, suggest that agranulocytosis arises from a different mechanism than that underlying PA-induced lupus.     

The Data Broadcast Problem with Non-Uniform Transmission Times

Abstract. The Data Broadcast Problem consists of finding an infinite schedule to broadcast a given set of messages so as to minimize a linear combination of the average service time to clients requesting messages, and of the cost of the broadcast. This problem also models the Maintenance Scheduling Problem and the Multi-Item Replenishment Problem. Previous work concentrated on a discrete-time restriction where all messages have transmission time equal to 1. Here, we study a generalization of the model to a setting of continuous time and messages of non-uniform transmission times. We prove that the Data Broadcast Problem is strongly NP -hard, even if the broadcast costs are all zero, and give 3 -approximation algorithms.     

Corneal manifestations of metabolic diseases

The extent to which sex differences in the behavioral effects of frontal injury in the adult rat can be attributed to differential exposure to testosterone (T) during development was investigated. The effects of these factors on brain weight and relative brain size were also examined. At birth, males were gonadectomized (GDX) or not and females were given T or oil injections. In adulthood, all animals were GDX or sham-operated and received either bilateral aspiration lesions of the medial frontal cortex or a sham operation. Rats were tested on the Morris water maze task, the radial arm maze (RAM), and the landmark water task. The effects of frontal injury on performance of the Morris water maze task were greater in rats not exposed to T at birth, there was no effect of neonatal T exposure on performance on the RAM, and on the landmark water task there was a complicated interaction of sex and neonatal T exposure in rats with frontal injury.     

Analysis of a Caenorhabditis elegans Twist homolog identifies conserved and divergent aspects of mesodermal patterning

Mesodermal development is a multistep process in which cells become increasingly specialized to form specific tissue types. In Drosophila and mammals, proper segregation and patterning of the mesoderm involves the bHLH factor Twist. We investigated the activity of a Twist-related factor, CeTwist, during Caenorhabditis elegans mesoderm development. Embryonic mesoderm in C. elegans derives from a number of distinct founder cells that are specified during the early lineages; in contrast, a single blast cell (M) is responsible for all nongonadal mesoderm formation during postembryonic development. Using immunofluorescence and reporter fusions, we determined the activity pattern of the gene encoding CeTwist. No activity was observed during specification of mesodermal lineages in the early embryo; instead, the gene was active within the M lineage and in a number of mesodermal cells with nonstriated muscle fates. A role for CeTwist in postembryonic mesodermal cell fate specification was indicated by ectopic expression and genetic interference assays. These experiments showed that CeTwist was responsible for activating two target genes normally expressed in specific subsets of nonstriated muscles derived from the M lineage. In vitro and in vivo assays suggested that CeTwist cooperates with the C. elegans E/Daughterless homolog in directly activating these targets. The two target genes that we have studied, ceh-24 and egl-15, encode an NK-2 class homeodomain and an FGF receptor (FGFR) homolog, respectively. Twist activates FGFR and NK-homeodomain target genes during mesodermal patterning of Drosophila and similar target interactions have been proposed to modulate mesenchymal growth during closure of the vertebrate skull. These results suggest the possibility that a conserved pathway may be used for diverse functions in mesodermal specification.