Influence of the grade on the variability of the mechanical properties of polypropylene waste.

The prior properties of recycled polypropylene depend on the origin of waste deposits and its chemical constituents. To obtain specific properties with a predefine melt flow index of polypropylene, the suppliers of polymer introduce additives and fillers. However, the addition of additives and/or fillers can modify strongly the mechanical behaviour of recycled polypropylene.

Family, personality, and social risk factors impacting the retention rates of first-year Hispanic and Anglo college students.

This study investigated familial and behavioral differences between Hispanic and Anglo-American first-year college students. Analyses of variance and chi-square analyses were used to test for ethnic differences in (a) risk factors associated with family dysfunction, family addictions, personality factors, and social experiences, (b) student problem behaviors, namely alcohol use, drug use, and eating disorders, (c) a one-year follow-up of student retention, and (d) specific factors related to retention at the one-year follow-up. The Hispanic freshmen appeared to demonstrate resilience despite a lack of mentoring and greater paternal addiction.

Xestospongins: potent membrane permeable blockers of the inositol 1,4,5-trisphosphate receptor.

Xestospongins (Xe's) A, C, D, araguspongine B, and demethylxestospongin B, a group of macrocyclic bis-1-oxaquinolizidines isolated from the Australian sponge, Xestospongia species, are shown to be potent blockers of IP3-mediated Ca2+ release from endoplasmic reticulum vesicles of rabbit cerebellum. XeC blocks IP3-induced Ca2+ release (IC50 = 358 nM) without interacting with the IP3-binding site, suggesting a mechanism that is independent of the IP3 effector site. Analysis of Pheochromocytoma cells and primary astrocytes loaded with Ca2+-sensitive dye reveals that XeC selectively blocks bradykinin- and carbamylcholine-induced Ca2+ efflux from endoplasmic reticulum stores.

Coping with school stress: a comparison of adolescents with and without learning disabilities.

The experience of school-related stress during the transition to junior high school is compared in a sample of 59 students with learning disabilities (27 females, 32 males) and 402 students without learning disabilities (241 females, 161 males). Using a checklist of 11 stressful school events, the authors found that adolescents with learning disabilities were more likely to report that they had failed a class and less likely to report they had been chosen for a school activity than their non-learning disabled peers. However, the two groups of students did not differ in their perceived stressfulness of any of the pertinent school events.