RESUMO
Self-assembly of 3D interiors and iridescence properties of poly(ß-hydroxybutyric acid-co-ß-hydroxyvaleric acid) (PHBV) periodic crystals are examined using microcopy techniques and microbeam X-ray diffraction. Morphology of PHBV can be tailored by crystallizing in presence of poly(vinyl acetate) (PVAc) or poly(trimethylene adipate) (PTA) for displaying desired periodicity patterns. The regular alternate-layered lamellae of banded PHBV crystal aggregates, resembling the structures the natural mineral moonstone or nacre, are examined to elaborate the origin of light interference and formation mechanisms of periodic lamellar aggregation of PHBV spherulites. By using PHBV as a convenient model and the crystal diffraction data, this continuing work demonstrates unique methodology for effectively studying the periodic assembly in widely varying polymers with similar aggregates. Grating structures in periodically assembled polymer crystals can be tailored for microstructure with orderly periodicity.
RESUMO
Kashin-Beck disease (KBD) is an endemic degenerative osteoarthropathy of uncertain etiology. The aim of our study was to identify changes in C-telopeptide of type II collagen (CTX-II), pyridinoline (PYD), and deoxypyridinoline (DPD) among KBD patients. 54 KBD patients and 78 healthy controls were included this study. Urinary samples were collected and measured by ELISA. The median quantities of PYD, CTX-II, and DPD of KBD patients were 1107.73 ng/µmol.cre, 695.11 ng/µmol.cre, and 1342.34 pml/µmol.cre, while the median quantities of healthy controls were 805.59 ng/µmol.cre, 546.47 ng/µmol.cre, and 718.15 pml/µmol.cre, respectively. The differences between KBD patients and healthy controls were statistically significant (Z = 4.405, 3.653, and 3.724; P < 0.001). The higher levels of PYD, CTX-II, and DPD detected in KBD patients indicate that they could be used as biomarkers of KBD.
