in this research, using pyrolysis of phenolic resin in the presence of silicon particles, the sic ceramic composite is formed. the samples were prepared by introducing 30, 35, 40, 45 and 50 wt% of si particles to the phenolic resin. the samples were cured at 180°c then carbonized at 1100°c. the final carbonized c/si composites are hot-pressed at 1500°c in inert atmosphere, which is more than th...

a new method was used to prepare abs/pa6 blends by in situ polymerization and compatibilization method. in this process, ε-caprolactam monomer was polymerized in presence of abs via activated anionic polymerization to produce pa6. the main ingredients of the reaction mixture included: monomer ()ε-caprolactam), catalyst na-caprolactamate), microactivator hdi)( and macro-activator sma)(. then, in...

UV radiation (UVR) and exposure to tobacco smoke, a source of polycyclic aromatic hydrocarbons (PAH), have been linked to skin carcinogenesis. UVR-mediated activation of the aryl hydrocarbon receptor (AhR) stimulates the transcription of CYP1A1 and CYP1B1, which encode proteins that convert PAH to genotoxic metabolites. We determined whether UVR exposure sensitized human keratinocytes to PAH-in...

background and objective: since the advent of mammography screening, ductal carcinoma in situ (dcis) of the breast has been diagnosed increasingly. in contrast to the situation in invasive breast carcinoma, there are only a few reports on androgen receptor (ar) status in dcis and few reports on estrogen (er) and progesterone (pr) receptors. materials and methods: ar expression was examined in 5...

purpose : this study was planned to evaluate the efficacy, safety and complication of photorefractive keratectomy (prk) as a retreatment of residual myopia after previous laser in situ keratomileusis (lasik). methods : in this descriptive study in ophthalmology ward, feiz hospital, isfahan university of medical sciences, iran, with the consideration of inclusion and exclusion criteria, 170 eyes...

A series of fluorine-containing amphiphilic ABC triblock copolymers comprising hydrophilic poly(ethylene glycol) (PEG) and poly(methacrylic acid) (PMAA), and hydrophobic poly(p-(2-(4-biphenyl)perfluorocyclobutoxy)phenyl methacrylate) (PBPFCBPMA) segments were synthesized by successive atom transfer radical polymerization (ATRP). First, PEG-Br macroinitiators bearing one terminal ATRP initiating...

We present a systematic methodology to functionalize magnetic nanoparticles through surface-initiated atom-transfer radical polymerization (ATRP). The magnetite nanoparticles are prepared according to the method proposed by Sun et al. (2004), which leads to a monodisperse population of ~ 6 nm particles stabilized by oleic acid. The functionalization of the nanoparticles has been performed by tr...

We previously studied a suitably 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCNs) that can be further functionalized with initiating sites and overcame the obstacle of performing atom transfer radical polymerization (ATRP) in the presence of neutral carboxylic acid sodium salt groups [1]. Herein, characterization of the modified TOCNs and of the products from ...

Here, we report on a new temperature responsive polymer brush system with a terminal ‘‘click’’ functionality. Bifunctionalized poly(N-isopropylacrylamide) (PNiPAAm) with distinct functional end groups was synthesized by atom transfer radical polymerization (ATRP) and grafted to a modified silicon substrate. The presence of the active terminal alkyne functionality is validated using an azidemodi...