Hydroxyapatite Mineralization on the Calcium Chloride Blended Polyurethane Nanofiber via Biomimetic Method

Polyurethane nanofibers containing calcium chloride (CaCl2) were prepared via an electrospinning technique for the biomedical applications. Polyurethane nanofibers with different concentration of CaCl2 were electrospun, and their bioactivity evaluation was conducted by incubating in biomimetic simulated body fluid (SBF) solution. The morphology, structure and thermal properties of the polyurethane/CaCl2 composite nanofibers were characterized by means of scanning electron microscopy (SEM), field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetry. SEM images revealed that the CaCl2 salt incorporated homogeneously to form well-oriented nanofibers with smooth surface and uniform diameters along their lengths. The SBF incubation test confirmed the formation of apatite-like materials, exhibiting enhanced bioactive behavior of the polyurethane/CaCl2 composite nanofibers. This study demonstrated that the electrospun polyurethane containing CaCl2 composite nanofibers enhanced the in vitro bioactivity and supports the growth of apatite-like materials

Socioeconomic disparities in behavioral risk factors and health outcomes by gender in the Republic of Korea

<p>Abstract</p> <p>Background</p> <p>Few studies have examined socioeconomic disparities in health and behavioral risk factors by gender in Asian countries and in South Korea, specifically. We investigated the relationship between socioeconomic position (education, income, and occupation) and subjective and acute and chronic health outcomes and behavioral risk factors by gender, and compared results from 1998 and 2005, in the Republic of Korea.</p> <p>Methods</p> <p>We examined data from a nationally representative stratified random sample of 4213 men and 4618 women from the 1998 Korea National Health and Nutrition Examination Survey, and 8289 men and 8827 women from the 2005 Korea National Health and Nutrition Examination Survey using General Linear Modeling and multiple logistic regression methods.</p> <p>Results</p> <p>Controlling for behavioral risk factors (smoking, drinking, obesity, exercise, and sleep), those in lower socioeconomic positions had poorer health outcomes in both self-reported acute and chronic disease and subjective measures; differences were especially pronounced among women. A socioeconomic gradient for education and income was found for both men and women for morbidity and self-reported health status, but the gradient was more pronounced in women. In 1998, the odds ratios (ORs) of higher morbidity for illiterate vs. college educated females was 5.4:1 and 1.9:1 for females in the lowest income quintile vs. the highest. The OR for education decreased in 2005 to 2.9:1 and that for income quintiles remained the same at 1.9:1. The OR of lower self-reported health status for illiterate vs. college educated females was 2.9:1 and 1.6:1 for females in the lowest income quintile vs. the highest in 1998, and 3.3:1 and 2.3:1 in 2005.</p> <p>Conclusions</p> <p>Among Korean adults, men and women in lower socioeconomic position, as denoted by education, income, and somewhat less by occupation, experience significantly higher levels of morbidity and lower self-reported health status, even after controlling for standard behavioral risk factors. Disparities were more pronounced for women than for men. Efforts to reduce health disparities in South Korea require attention to the root causes of socioeconomic inequality and gender differences in the impact of socioeconomic position on health.</p

Site-Specific Deposition of Au Nanoparticles in CNT Films by Chemical Bonding

There has been no attempt to date to specifically modify the nodes in carbon nanotube (CNT) networks. If the nodes can be modified in favorable ways, the electrical and/or thermal and/or mechanical properties of the CNT networks could be improved. In an attempt to influence the performance as a transparent conductive film, gold nanoparticles capped with the amino acid cysteine (Au-CysNP) have been selectively attached at the nodes of multiwalled carbon nanotubes (MWCNTs) networks. These nanoparticles have an average diameter of 5 nm as observed by TEM. FTIR and X,PS were used to characterize each step of the MWCNT chemical. functionalization process. The chemical process was designed to favor selective attachment at the nodes and not the segments in the CNT networks. The chemical processing was designed to direct formation of nodes where the gold nanoparticles are. The nanoparticles which were loosely held in the CNT network could be easily washed away by solvents, while those bound chemically remained. TEM results show that the Cys-AuNPs are preferentially located at the nodes of the CNT networks when compared to the segments. These nanoparticles at the nodes were also characterized by a novel technique called diffraction scanning transmission electron microscopy (D-STEM) confirming their identity. Four-probe measurements found that the sheet resistance of the modified CNT networks was half that of similarly transparent pristine multiwalled CNT networks

Head-to-tail dimerization and organogelating properties of click peptidomimetics

Click triazole-based oligopeptides 1-3 were found to self-dimerize (K dim ≈ 10-680 M -1) in a head-to-tail fashion based on 1H variable concentration, 2D, and H/D exchange NMR, VPO, CD, FT-IR studies and Gaussian 03 simulations. The dimerization constant K dim was shown to increase with increasing number of the amino acid units. Within the same oligomeric series, the K dim value is strongly affected by the size of the C-terminal end group. The tripeptides 2 are also excellent organogelators of aromatic solvents. © 2011 American Chemical Society.link_to_subscribed_fulltex