Influence of free volume fraction,inter/intramolecular energy ratio,and chain segment density on the Gibbs-DiMarzio theory of the glass transition

Based upon computer analysis, the Gibbs-DiMarzio (G-DM) theory is evaluated for the case of (a) constant V₀ and (b) constant r where V₀ is the fractional free volume at T_g and r is the ratio of the hole (E₀) to the flex (ε) energy. For each respective case, results are presented in a reduced variables format that indicate the extent to which r and V₀ vary at the transition temperature as a function of the reciprocal degree of polymerization (P^?1). To further account for chemical differences that exist among polymers, an index (n) is introduced that ultimately incorporates the effective number average of chain atom segments (x?) per P?. Using these reduced variables plots, the effects of V₀, r, and n are compared with the T_g data for four well-documented polymers. Although the theory adequately describes the PMMA, PS, and PVC data, for PαMS the fit is doubtful. The analysis demonstrates that, in order to maintain V₀ within the range of 0.015–0.045, r must remain within approximately 1.0–1.1. Moreover, under conditions of either constant V₀ or r, other more flexible polymers require that $\text{n?10}$.     

Is a sense of inequity an ancestral primate trait? Testing social inequity in cotton top tamarins (Saguinus oedipus).

To address a controversy in the literature concerning whether monkeys show an aversion to inequity, individuals of a New World monkey species, cotton top tamarins (Saguinus oedipus) were tested in an offering task and in a bartering task. At issue was whether the monkeys rejected rewards because of a violation of expectancy of the preferred reward, or whether they rejected rewards because of a sensitivity to socially mediated inequity. The data from both tasks indicated that the subjects were more likely to reject when preferred rewards were presented, either because of another animal eating the reward (the social condition) or because of rewards being presented but inaccessible. The bartering task led to the only behavioral indication of aversion due specifically to social inequity, which was demonstrated when tamarins' sensitivity to the difference in rewards increased with exposure to other tamarins working to receive the preferred rewards. The results suggest that social inequity aversion will be assessed by tamarins, and possibly by other primates, only under conditions of limited resources and a requirement of work, which may make the situation a bit more competitive and thus drives attention toward both social and reward evaluation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimal levels of emotional arousal in experiential therapy of depression.

Objective: To determine the relationship between length of time spent expressing highly aroused emotion and therapeutic outcome. Method: Thirty-eight clients (14 male, 24 female) between the ages of 22 and 60 years (M = 39.5, SD = 9.71), treated for depression with experiential therapy, were rated on working alliance and expressed emotional arousal (with the Client Expressed Emotional Arousal Scale) in their three highest arousal sessions. Among the clients, 34 were of European ethnicity, 2 were of Asian ethnicity, 1 was of Latino ethnicity, and 1 was of Caribbean–Canadian ethnicity. Clients were administered the short form of the Working Alliance Inventory following their 4th therapy session and also completed, pre- and posttherapy, the Beck Depression Inventory (BDI), the Global Severity Index (GSI) of the Symptom Checklist–90–Revised (SCL-90-R), the Inventory of Interpersonal Problems, and the Rosenberg Self-Esteem Scale. Results: Hierarchical regressions showed that a nonlinear pattern of expressed emotional arousal predicted outcome significantly above the alliance. This combination predicted 30% of outcome variance on the BDI and 24% on the GSI (p     

Self-blocking of dislocations in intermetallic compound Ni<Subscript>3</Subscript>Ge: Cubic slip

Self-blocking of dislocations belonging to the cube plane has been detected in the intermetallic compound Ni₃Ge. The nature of cubic slip has been clarified. The experiments included deformation at a temperature above T _max (the temperature of the yield-stress peak) and subsequent heating without stress. In addition, changes in the dislocation structure upon slow cooling from the temperature of the preliminary deformation have been investigated; in doing so, self-blocking of dislocations has been revealed for the first time. Based on the totality of experimental data, a conclusion has been made on the two-valley potential relief for a dislocation motion in the cube plane. It is the difference in the depths between the Peierls valley (a diffuse core in the cube plane) and the deepest valley (a superpartial dislocation split in the octahedron plane) that provides for the driving force of self-blocking in the absence of an external stress. Different aspects of cubic slip have been considered: the disappearance of cubic slip at T < T _max and, correspondingly, the nonobservation of an anomalous behavior of the yield stress, as well as the disappearance of octahedral slip at T > T _max.     

Fusion-competent vaccines: broad neutralization of primary isolates of HIV

Current recombinant human immunodeficiency virus (HIV) gp120 protein vaccine candidates are unable to elicit antibodies capable of neutralizing infectivity of primary isolates from patients. Here, "fusion-competent" HIV vaccine immunogens were generated that capture the transient envelope-CD4-coreceptor structures that arise during HIV binding and fusion. In a transgenic mouse immunization model, these formaldehyde-fixed whole-cell vaccines elicited antibodies capable of neutralizing infectivity of 23 of 24 primary HIV isolates from diverse geographic locations and genetic clades A to E. Development of these fusion-dependent immunogens may lead to a broadly effective HIV vaccine.     

High-dose thiotepa and etoposide-based regimens with autologous hematopoietic support for high-risk or recurrent CNS tumors in children and adults

The prognosis in patients with primary brain tumors treated with surgery, radiotherapy and conventional chemotherapy remains poor. To improve outcome, combination high-dose chemotherapy (HDC) has been explored in children, but rarely in adults. This study was performed to determine the tolerability of three-drug combination high-dose thiotepa (T) and etoposide (E)-based regimens in pediatric and adult patients with high-risk or recurrent primary brain tumors. Thirty-one patients (13 children and 18 adults) with brain tumors were treated with high-dose chemotherapy: 19 with BCNU (B) and TE (BTE regimen), and 12 with carboplatin (C) and TE (CTE regimen). Patients received growth factors and hematopoietic support with marrow (n = 15), peripheral blood progenitor cells (PBPC) (n = 11) or both (n = 5). The 100 day toxic mortality rate was 3% (1/31). Grade III/IV toxicities included mucositis (58%), hepatitis (39%) and diarrhea (42%). Five patients had seizures and two had transient encephalopathy (23%). All patients had neutropenic fever and all pediatric patients required hyperalimentation. Median time to engraftment with absolute neutrophil count (ANC) >0.5 x 10(9)/l was 11 days (range 8-37 days). Time to ANC engraftment was significantly longer (P = 0.0001) in patients receiving marrow (median 14 days, range 10-37) than for PBPC (median 9.5 days, range 8-10). Platelet engraftment >50 x 10(9)/l was 24 days (range 14-53 days) in children. In adults, platelet engraftment >20 x 10(9)/l was 12 days (range 9-65 days). In 11 patients supported with PBPC, there was a significant inverse correlation between CD34+ dose and days to ANC (rho = -0.87, P = 0.009) and platelet engraftment (rho = -0.85, P = 0.005), with CD34+ dose predicting time to engraftment following HDC. Overall, 30% of evaluable patients (7/24) had a complete response (CR) (n = 3) or partial response (PR) (n = 4). Median time to tumor progression (TTP) was 7 months, with an overall median survival of 12 months. These TE-based BCNU or carboplatin three-drug combination HDC regimens are safe and tolerable with promising response rates in both children and older adults.     

The guideline interchange format: a model for representing guidelines

Carboxylate and sulfate groups were introduced at the surface of poly(ethylene) (PE) samples. This was accomplished by coating and immobilizing sodium 10-undecenoate (C11(:)) and 10-undecene sulfate (S11(:)) on the polymer by means of an argon plasma treatment. The composition of the coated surfactant layer was proportional to the composition of the coating solution. The thickness of the surfactant layer on the surface of PE samples, which were precoated from an aqueous solution with a total surfactant concentration of 0.30 M, was about 55 A. The presence of carboxylate and sulfate groups after plasma treatment of the precoated surfaces was confirmed by X-ray photoelectron spectroscopy (XPS). About 20% of the initial amount of functional groups of the coated surfactants was retained at the PE surface. The ratio of carboxylate/sulfate groups at the plasma treated surfaces was dependent on the composition of the precoated surfaces. The minimum surface density of these groups on the resulting samples was about one group per 40 A2.