Cyclodextrins in Polymer Synthesis: Free Radical Polymerization of β‐Cyclodextrin Complexes of Photosensitive Mesoionic 6‐Oxo‐1,6‐dihydropyrimidin‐3‐ium‐4‐olates in Aqueous Medium

Solid mesoionic 2‐[2‐(isopropenylcarbonyloxy)ethylthio]‐1‐methyl‐6‐oxo‐3‐phenyl‐5‐propyl‐1,6‐dihydropyrimidin‐3‐ium‐4‐olate was complexed in water using β‐cyclodextrin (β‐CD) and randomly methylated β‐CD, which resulted in polymerizable complexes with 2:1 stoichiometry. The β‐CD complex was characterized using ¹H NMR, ROESY NMR and UV spectroscopy. Polymerization of the complex prepared from methylated β‐CD led to a photosensitive polymer, which precipitated during polymerization and was nearly free of CD. Polymerization was carried out with a water‐soluble redox initiator. In addition, a copolymer with methyl methacrylate was prepared from the complexes, which showed a different mass‐dependent distribution in the incorporation in comparison to a copolymer prepared without CD in organic solvents.

     

A Novel Macroinitiator for the Synthesis of Triblock Copolymers via Atom Transfer Radical Polymerization: Polystyrene‐block‐poly(bisphenol A carbonate)‐block‐polystyrene and Poly(methyl methacrylate)‐block‐poly(bisphenol A carbonate)‐block‐poly(methyl methacrylate)

Summary: Bis(hydroxy)telechelic bisphenol A polycarbonate (PC) was prepared via melt polycondensation of bisphenol A (BPA) and diphenyl carbonate (DPC) using lanthanum(III ) acetylacetonate as a catalyst for transesterification. Subsequently, the polycarbonate was converted to a bifunctional macroinitiator for atom transfer radical polymerization (ATRP) with the reagent, α‐chlorophenylacetyl chloride. The macroinitiator was used for the polymerization of styrene (S) and methyl methacrylate (MMA) to give PS‐block‐PC‐block‐PS and PMMA‐block‐PC‐block‐PMMA triblock copolymers. These block copolymers were characterized by NMR and GPC. When styrene and methyl methacrylate were used in large excess, significant shifts toward high molecular weights were observed with quantitative consumption of the macroinitiator. Several ligands were studied in combination with CuCl as the ATRP catalyst. Kinetic studies reveal the controlled nature of the polymerization reaction for all the ligands used.

Formation of a bifunctional ATRP macroinitiator by esterification of bis(hydroxy)telechelic PC with α‐chlorophenylacetyl chloride.     

Temperature dependence of M pilus formation as demonstrated by electron microscopy

The formation of IncM plasmid encoded pili is dependent on the incubation temperature of the corresponding host strains. By labelling the short, rigid M pili with the donor specific bacteriophage luminal diameter M, the presence of pili at 30 degrees C but not at 37 degrees C incubation temperature could be demonstrated for E. coli K12 substrains carrying different IncM group plasmids. In contrast, such a temperature dependence of M pilus formation is not observed in S. typhimurium substrains.     

A role for hyaluronan in macrophage accumulation and collagen deposition after bleomycin-induced lung injury

Elevated concentrations of hyaluronan (HA) are associated with the accumulation of macrophages in the lung after injury. We have investigated the role of HA in the inflammatory and fibrotic responses to lung injury using the intratracheal instillation of bleomycin in rats as a model. After bleomycin-induced lung injury, both HA content in bronchoalveolar lavage (BAL) and staining for HA in macrophages accumulating in injured areas of the lung were maximal at 4 d. Increased HA in BAL correlated with increased locomotion of isolated alveolar macrophages. HA-binding peptide was able to specifically block macrophage motility in vitro. Importantly, systemic administration of HA-binding peptide to rats before injury not only decreased alveolar macrophage motility and accumulation in the lung, but also reduced lung collagen alpha (I) messenger RNA and hydroxyproline contents. We propose a model in which HA plays a critical role in the inflammatory response and fibrotic consequences of acute lung injury.     

Dielectric properties of a combined main-chain/side-chain liquid-crystalline polymer

The dielectric relaxation properties of a combined main-chain/side-chain liquid-crystalline polymer were investigated. It was found that the rotation of the side chain about the main chain (δ-process) is not as strongly restricted as in side-chain liquid-crystalline polymers. This is attributed to the facts that the side chain is attached to the flexible spacer within the chain backbone and that the concentration of the side chains is comparatively small. Two low-temperature relaxation processes were observed to occur in the glassy smectic and the crystalline state. They are attributed to intramolecular motions with in the mesogenic groups.     

Differential vulnerability of male and female rats to the timing of various perinatal insults

The results of five experiments showed that exposure to diazepam, hypoxia and monosodium glutamate during the prenatal or early postnatal period of rapid brain development may result in different behavioral consequences depending on the timing of the exposure rather than the nature of the agent. Moreover, male and female offspring may be affected differently by the same agent at different periods of development. Prenatal insults of various kinds impair the later performance of males but not the females in a complex learning task, while postnatal insults seem to affect detrimentally this same behavior in both males and females. The effects of perinatal insults on maze learning and open field activity do not lend themselves to explanation by "feminization" or "masculinization" of behavior caused by interference with prenatal gonadal hormones.     

Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in cold-adapted rats

The toxicity of 60g/kg 2,3,7,8-tetrachlorodi-benzo-p-dioxin (TCDD) given IP in corn oil/5% acetone was examined in male Sprague-Dawley rats adapted to 25 °C or 4 °C ambient temperature. Cold exposure significantly reduced mean time to death and tended to increase mortality. Body weight at the time of death was reduced at both ambient temperatures to about the same extent. Thus, the rate of body weight loss was about twice as fast in nonsurvivors at 4°C than at 25 °C. There was a continuous decrease in feed intake of the non-survivors at 25 °C until death. However, no reduction in feed intake occurred in any of the rats at 4 °C ambient temperature. At 14 days after dosing all TCDD-dosed animals were hypothyroid in terms of T₄ but essentially euthyroid in terms of T₃. Oxygen consumption at 10 days after dosing was reduced to the same extent in all TCDD-dosed rats without regard to survival status. By day 20 after TCDD dosage, survivors increased their oxygen consumption at both ambient temperatures to nearly control levels whereas non-survivors were unable to do so. Body temperature of all animals remained within normal range except for the non-survivors, which showed reduced rectal temperature shortly before death. It is concluded (1) that cold adaptation aggravates the toxicity of TCDD, (2) that reduced feed intake alone cannot explain TCDD-induced wasting syndrome, (3) that reduced oxygen consumption in TCDD-treated rats may be due to reduced feed intake and/or altered thyroid hormone status, and (4) that TCDD is likely to activate metabolic pathways which represent a wasteful utilization of ingested and/or stored energy.     

Determinants of the Consumption of Regular Soda,Sport, and Energy Beverages in Spanish Adolescents

Increasing sugar-sweetened beverages (SSB) consumption and associated health impacts warrant health-policy action. We assessed associations of socioeconomic and lifestyle variables with adolescents’ consumption of regular soda (RSD), sport (SD), and energy (ED) drinks. Cross-sectional study of 3930 Spanish adolescents (2089 girls, 1841 boys) aged 13–18 years). We compared frequency of consuming each SSB type (European Food Safety Authority questionnaire) with sociodemographic and lifestyle variables (standardized questions). RSD, SD, and ED were consumed at least weekly by 72.7%, 32.3%, and 12.3% of participants, respectively, and more frequently (p < 0.001) by boys, compared to girls. Multivariate ordinal logistic regression showed inverse association between RSD, SD, and ED consumption and parental occupation-based socioeconomic status (p < 0.01). Daily smoking was associated (p < 0.001) with higher ED (OR 3.64, 95% CI 2.39–5.55) and RSD (OR 2.15, 95% CI 1.56–2.97) consumptions. SD intake was associated inversely with smoking (OR 0.60, 95% CI 0.40–0.89, p = 0.012) and directly with physical activity (OR 2.93, 95% CI 2.18–3.95, p < 0.001). School performance was lower among ED (OR 2.14, 95% CI, 1.37–3.35, p = 0.001) and RSD (OR 1.81, 95% CI 1.24–2.64, p = 0.002) consumers, compared to SD. Maleness and low socioeconomic status predicted SSB consumption. Smoking and low school performance were associated with higher ED and RSD intakes.