Enhancement of T-g of Poly(l-lactide) by Incorporation of Biobased Mandelic-Acid-Derived Phenyl Groups by Polymerization and Polymer Blending

A high-molecular-weight polyester of poly(mandelate-co-lactate) (PML) is prepared by ring-opening polymerization of stereo-configuration controlled cyclic diester monomers of methyl-6-phenyl-1,4-dioxane-2,5-dione (MPDD) and lactide. The attained PML shows excellent glassy properties, although the original stereo-configuration of MPDD is not preserved. The intrinsic high glass transition temperature (Tg) of PML is promising, and it is able to be further enhanced by thermal treatment to as high as 90 °C. Interestingly, the enhanced high Tg is attained by only 15 mol% of mandelate content in the polymer chain which is far lower than the ones suggested by theoretical calculation. The enhancement in Tg is also attained by polymer blending of PML and poly(l-lactide) (PLLA). The Tg of the polymer blend also reaches 90 °C which is almost 20 °C higher than the ones suggested by theoretical calculations. These results indicate that the rigid mandelate unit consisting of phenyl groups in PML chain effectively interact with PLLA chains in amorphous domain to restrict their chain mobility. The thermal and glassy properties are sufficient to explore new applications in engineering fields

The saw-tooth sign as a clinical clue for intrathoracic central airway obstruction

BACKGROUND: The saw-tooth sign was first described by Sanders et al in patients with obstructive sleep apnea syndrome as one cause of extrathoracic central airway obstruction. The mechanism of the saw-tooth sign has not been conclusively clarified. The sign has also been described in various extrathoracic central airway diseases, such as in burn victims with thermal injury to the upper airways, Parkinson’s disease, tracheobronchomalacia, laryngeal dyskinesia, and pedunculated tumors of the upper airway. CASE PRESENTATION: A 61-year-old man was referred to our hospital with a two-month history of persistent dry cough and dyspnea. He was diagnosed with lung cancer located in an intrathoracic central airway, which was accompanied by the saw-tooth sign on flow-volume loops. This peculiar sign repeatedly improved and deteriorated, in accordance with the waxing and waning of central airway stenosis by anti-cancer treatments. CONCLUSION: This report suggests that the so-called saw-tooth sign may be found even in intrathoracic central airway obstruction due to lung cancer

An Adult Case of Kawasaki Disease in a Pregnant Japanese Woman: A Case Report

Kawasaki disease is an acute febrile disease predominantly seen in young children. We report a case of Kawasaki disease in a 32-year-old pregnant woman. She developed a generalized erythematous skin rash accompanied by high fever. Bilateral conjunctival congestion, tender cervical lymphadenopathy, an edematous lower lip and peripheral edema followed by desquamation were observed. She was successfully treated with aspirin and intravenous gammaglobulin (1 g/kg/day). Her course was not complicated by coronary artery aneurysm and she delivered a healthy baby. To the best of our knowledge, this is the first case of Kawasaki disease in a pregnant woman. We suggest that Kawasaki disease should be included in the differential diagnosis of a generalized, erythematous skin rash accompanied by high fever in adults