The influence of matrix microstructure and particle reinforcement on the creep behavior of 2219 aluminum

The influence of matrix microstructure and reinforcement with 15 vol pct of TiC particles on the creep behavior of 2219 aluminum has been examined in the temperature range of 150 ‡C to 250 ‡C. At 150 ‡C, reinforcement led to an improvement in creep resistance, while at 250 ‡C, both materials exhibited essentially identical creep behavior. Precipitate spacing in the matrix exerted the predominant influence on minimum creep rate in both the unreinforced and the reinforced materials over the temperature range studied. This behavior and the high-stress dependence of minimum creep rate are explained using existing constant structure models where, in the present study, precipitate spacing is identified as the pertinent substructure dimension. A modest microstructure-independent strengthening from particle reinforcement was observed at 150 ‡C and was accurately modeled by existing continuum mechanical models. The absence of reinforcement creep strengthening at 250 ‡C can be attributed to diffusional relaxation processes at the higher temperature.     

The FGF receptor-1 tyrosine kinase domain regulates myogenesis but is not sufficient to stimulate proliferation

STUDY OBJECTIVES: The aims of this study were: to evaluate the performance of a novel arterial biopsy catheter in obtaining pulmonary endovascular samples in hypertensive dogs; to compare the results of pulmonary endoarterial biopsy in hypertensive vs normotensive dogs; and to assess the histologic changes in the hypertensive model. DESIGN AND INTERVENTIONS: Thirty-four dogs (27 with normal pulmonary arterial pressures and seven with pulmonary hypertension) were catheterized through an external jugular vein to obtain endovascular biopsy samples from distal pulmonary arteries 2 to 3 mm in luminal diameter. To induce pulmonary hypertension, seven dogs were given repeated infusions of 0.6- to 0.9-mm ceramic microspheres into the superior vena cava. Endoarterial samples were obtained at pulmonary systolic arterial pressures ranging from 10 to 110 mm Hg. MEASUREMENTS AND RESULTS: Sixty-two biopsy catheterization procedures were performed in the 34 dogs. After 12 initial procedures of technique refinement, endoarterial samples were obtained in each of the last 50 procedures (21 in normotensive dogs and 29 in hypertensive dogs). The average number of endovascular biopsy samples retrieved was 7.1 (range, 2 to 12) from a mean of 8.6 (range, 2 to 15) biopsy attempts per catheterization (success rate=83%). The average biopsy piece measured 1.13 mm in length, 0.33 mm in depth, and up to 1.0 mm in width. The biopsy success rates and endoarterial sample sizes were similar in normotensive and hypertensive dogs. Smooth muscle cells and endothelial cells were grown from the biopsy samples. There were no significant procedural complications, except for one self-limited hemorrhage. Histologically, samples obtained from dogs with pulmonary hypertension showed characteristic changes when compared with biopsies from normotensive dogs. CONCLUSION: This new endoarterial biopsy catheter was safe and effective when used to obtain pulmonary endoarterial samples in dogs with normal and experimentally elevated pulmonary arterial pressures. The quality and quantity of the biopsy samples allowed identification of pathologic changes.     

Anatomy and histology of the A5 pulley

Sustained iontophoresis of NMDA potentiated visual responses for minutes after the application in 16 of 38 cells (42%), peaking 3 min after the end of the application and declining to control levels within 12 min. Potentiation was also seen after application of ACPD (36%, n = 14) and AMPA (29%, n = 14), but not after application of ACh (n = 20). ACh also excites dLGN cells, but does not interact with amino acid receptors, and ACh receptors are not directly involved in the transmission of visual information. We suggest that this modulation is a form of visually induced potentiation which permits dynamic modification of the strength of visual information to be relayed to the cortex depending upon the history of previous activity levels.     

Nonimmune fetal hydrops: diagnosis and obstetrical management

As the incidence of Rh-isoimmunization has been decreasing with the availability of Rh immune globulin, the proportion of cases of fetal hydrops from nonimmune causes has increased. Evaluation of the fetus with hydrops requires an integrated approach, beginning with targeted ultrasound evaluation and potentially including maternal and fetal blood testing and other invasive testing. Because the list of conditions that may cause hydrops is long and continues to grow, it is often difficult to make a precise diagnosis; however, through a systematic approach, one may frequently narrow the etiology to a category of disorders and determine whether any interventions are available that are likely to be helpful in improving the outlook for the fetus.     

Examining the alliance using the Psychotherapy Process Q-Set.

The alliance between therapist and patient was investigated using the Psychotherapy Process Q-Set (PQS), an instrument that quantitatively describes therapy sessions in a manner that captures the complexity of the therapy process. More specifically, the PQS was used to examine the treatment processes being assessed by observer ratings on the California Psychotherapy Alliance Scales (CALPAS). Using data from 30 brief psychodynamic psychotherapy treatments (patients aged 20–81 yrs), three PQS factors were found to be associated with alliance: Patient–Therapist Interaction, Patient Capacity/Commitment, and Therapist Countertransference. In multiple regression analyses with scales constructed from these three factors, Patient–Therapist Interaction was found to predict alliance ratings, while the other two aspects of the treatment process did not account for any significant additional variance in the alliance ratings. Results suggest that Patient–Therapist Interaction plays a defining role in the alliance construct, as assessed by the observer version of the CALPAS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Opinions of consultant obstetricians in the Northern Region regarding the provision of intrapartum care by GPs

Consultants with experience of GP intrapartum care believe it is safe for the low-risk woman. However, GPs are perceived as lacking enthusiasm and as having varying degrees of obstetric expertise. Consultants feel that women themselves are not requesting more intrapartum care from GPs.     

Epitope mapping using histidine-tagged protein fragments: application to Escherichia coli RNA polymerase sigma 70

The pathogenic Neisseria have exploited the processes of horizontal DNA transfer and genetic recombination as mechanisms for the generation of extensive protein variation and modulation of gene expression. Localized recombinations have been well documented in members of multigene families as have alterations in short repetitive sequences. Here we report an analysis of the chromosomal structure of a defined lineage of Neisseria gonorrhoeae strain MSl1 pilin variants. This study reveals the occurrence of large rearrangements, including the amplification of a 26 kb region and an inversion involving more than a third of the chromosome. Additionally, a restriction site polymorphism that correlates with pilin expression has been observed. These findings highlight the flexibility of the gonococcal genome.