“A novel combined catalyst of fumed silica (SiO2) with Ni2O3 was demonstrated to be more efficient than SiO2 or Ni2O3 alone in enhancing the char yield of poly(lactic acid) (PLA) and improving its char layer structure, which greatly enhanced the flame retardancy of PLA. The results of field-emission scanning electron microscope, transmission electron microscope, X-ray diffraction, Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed that the residual chars mainly consisted of block-like carbon and carbon nanotubes with VX-680 ic50 some surface functional groups. The
flame retardancy of PLA and its composites was studied by cone calorimeter test. The heat release rate and total heat release of PLA composites containing both SiO2 and Ni2O3 decreased significantly in comparison with those of neat PLA. The investigation of the this website synergetic mechanism showed that in the presence of both SiO2 and Ni2O3, a large amount of chars were in situ formed from the catalytic carbonization of degradation products of PLA by Ni2O3 during combustion.
This not only reduced the release of flammable degradation products, but also acted as an insulating barrier to prohibit the oxygen and feedback of heat from reaching the underlying substrate. On the other hand, the formation of a percolated network structure of SiO2 and Ni2O3 particles in PLA matrix increased the melt viscosity of PLA and facilitated the formation of a more compacted protective layer, which promoted the flame retardancy of PLA. (C) 2014 Elsevier Ltd. All rights reserved.”
“PURPOSE. To determine how visual field loss as assessed by microperimetry is correlated with deficits in face recognition. METHODS. Twelve patients (age range, 26-70 years) with impaired visual sensitivity in the central visual field caused by a variety of pathologies and 12 normally sighted controls (control subject [CS] group; age range, 20-68 years) performed a face recognition LGX818 cell line task for blurred
and unblurred faces. For patients, we assessed central visual field loss using microperimetry, fixation stability, Pelli-Robson contrast sensitivity, and letter acuity. RESULTS. Patients were divided into two groups by microperimetry: a low vision (LV) group (n = had impaired sensitivity at the anatomical fovea and/or poor fixation stability, whereas a low vision that excluded the fovea (LV: F) group (n = 4) was characterized by at least some residual foveal sensitivity but insensitivity in other retinal regions. The LV group performed worse than the other groups at all blur levels, whereas the performance of the LV: F group was not credibly different from that of the CS group. The performance of the CS and LV: F groups deteriorated as blur increased, whereas the LV group showed consistently poor performance regardless of blur.