Crystallization of a copolyester in microlayers and blends with polycarbonate

The crystallization behavior of coextruded microlayered sheets comprised of 657 alternating layers of polycarbonate (PC) and a miscible copolyester of mainly 1,4-cyclohexanedimethanol and terephthalic acid (KODAR) was investigated as a function of annealing time when the KODAR was crystallized isothermally from the glass at 195°C. Comparisons were made with crystallization of KODAR alone, and with crystallization of KODAR from melt blends with PC. The kinetics of crystallization and the morphology of the crystallized KODAR were characterized with differential scanning calorimetry, and by examination of thin sections microtomed from annealed specimens in the polarized light microscope and the transmission electron microscope. The growth rate of small, birefringent KODAR spherulites was non-linear, and was strongly affected by diffusion of PC into the KODAR layers. Diffusion of amorphous PC into the KODAR layers retarded nucleation and spherulite growth and decreased spherulite density. The effect became more pronounced as the KODAR layer thickness was reduced. Spherulities nucleated randomly throughout the KODAR layers in the PC/KODAR 20/80 (w/w) microlayer and grew rapidly to form a continuous layer of impinged spherulites. In contrast, spherulites in the PC/KODAR 40/60 and 60/40 microlayers nucleated and grew along the center of the KODAR layers where the KODAR concentration was highest.     

Exchangeable magnesium pool masses in healthy women: effects of magnesium supplementation.

BACKGROUND: Studying magnesium pools in the body with use of stable isotopes may be helpful for evaluating magnesium status. Data on the evaluation of magnesium pools in humans are scarce. OBJECTIVE: We undertook this study to evaluate the effects of a magnesium supplementation program on the size of the exchangeable body pools of magnesium and on classic indexes of magnesium status in healthy women with normal magnesium status. DESIGN: Ten healthy women participated in a kinetic study with magnesium stable isotopes before and after 8 wk of magnesium supplementation. Each woman received 3 supplements containing 5.08 mmol (122 mg) elemental Mg/d (366 mg/d). Before and at the end of the supplementation period, each woman received an intravenous injection of 1.67 mmol (40 mg) (25)Mg, and the plasma magnesium disappearance curve was followed for the next 7 d. Two methods were used to analyze the exchangeable pools of magnesium: 1) formal multicompartmental modeling and 2) a simplified estimation of the total mass of the rapidly exchangeable magnesium pool (EMgP). RESULTS: In these healthy women, exchangeable magnesium pools represented 11-12% of total body magnesium on the basis of multicompartmental analysis. The simplified estimation of EMgP overestimated the size of the exchangeable magnesium pools by approximately 45-50%. Eight weeks of magnesium supplementation did not significantly modify the size of the exchangeable magnesium pools, whereas urinary magnesium excretion was significantly higher after 8 wk of supplementation. CONCLUSION: Women with no clinical evidence of magnesium deficiency may not respond to short-term supplementation with increases in the mass of the exchangeable magnesium body pool or in magnesium turnover rates.     

Low doses of the 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH DPAT) increase ethanol intake

Previous work has reported that the 5-hydroxytryptamine (5-HT)_1A agonist, 8-hydroxy 2-(di-n-propylamino)tetralin (8-OH DPAT), reduces ethanol intake by rats. However, as 8-OH DPAT reduces 5-HT neurotransmission, these findings are inconsistent with the proposed inhibitory role of central 5-HT neurons on ethanol intake. We examined the effect of 8-OH DPAT on ethanol, water and food intake in rats maintained on a limited access schedule using a lower dose range (6–250 µg/kg) and by assessing concomitant changes in behaviour. Low doses of 8-OH DPAT enhanced ethanol intake even when food and water were offered as alternatives. Suppression in ethanol intake was observed at higher doses where elements of the 5-HT syndrome were apparent. Similar observations were made in both fluid and non-fluid deprived water drinking rats, suggesting the latter effect is non-selective. Therefore 8-OH DPAT may both increase or decrease ethanol consumption in the rat depending on the dose used.     

Impact of automatic orders to discontinue vancomycin therapy on vancomycin use in an antimicrobial stewardship program.

We examined the possible unintended consequences of a 72-hour automatic order to discontinue vancomycin therapy in an antimicrobial stewardship program (ASP). Of 120 patients, 11 had vancomycin therapy discontinued at 72 hours without a call to the ASP, and 7 experienced a treatment interruption of 6-36 hours. All discontinuation of therapy was considered appropriate, and the 7 treatment interruptions did not have clear clinical consequences. Only one-third of patients had ASP stickers that warned of impending discontinuation of vancomycin therapy placed appropriately in the medical record.     

Preeclampsia and Chlamydia pneumoniae: is there a link?

Several parallels exist between preeclampsia and atherosclerosis. Both are multifactorial diseases that share risk factors such as obesity, insulin resistance, lipid abnormalities, and elevated serum homocysteine. There are also similarities in the biochemical changes seen in both diseases, including elevated serum triglycerides, decreased HDL cholesterol and enhanced formation of small, dense LDL particles as well as vascular atherosclerotic lesions. Chronic infection with Chlamydia pneumoniae has been linked to coronary artery disease. This study evaluated a possible link between the incidence of preeclampsia and infection with C. pneumoniae by examining the rate of seropositivity in 81 women with preeclampsia, and 206 women with normal pregnancies. Although our data confirmed well-known risk factors for preeclampsia such as obesity, diabetes, and hypertension, we found no difference in the rate of seropositivity between preeclampsia and normal pregnancy. On the contrary, the presence of chlamydial antibodies was lower in preeclampsia. Multiparous women with preeclampsia showed a significantly lower rate of seropositivity than multiparous normal women and nulliparous preeclamptics. In addition, women with a history of preeclampsia who developed preeclampsia in the current pregnancy also had a significantly lower rate of seropositivity.     

Classroom seating for children with attention deficit hyperactivity disorder: therapy balls versus chairs.

OBJECTIVE: The purpose of this study was to investigate the effects of therapy balls as seating on in-seat behavior and legible word productivity of students with attention deficit hyperactivity disorder (ADHD). Additionally, social validity was assessed to evaluate teacher and student opinions regarding the intervention. METHOD: A single subject, A-B-A-B interrupted time series design was employed across 3 students (2 males, 1 female) with ADHD. The study was conducted in a 4th grade inclusive classroom during daily language arts. During phases 1 and 3, the 3 participants and all other class members sat on chairs (in-seat on chair); during phases 2 and 4, everyone sat on therapy balls (in-seat on ball). Dependent variables were in-seat behavior and legible word productivity. Data were graphed and visually analyzed for differences between phases. RESULTS: Results demonstrated increases in in-seat behavior and legible word productivity for the students with ADHD when seated on therapy balls. Social validity findings indicated that generally the teacher and students preferred therapy balls. CONCLUSION: This study provides evidence that use of therapy balls for students with ADHD may facilitate in-seat behavior and legible word productivity.