2,4-Dichlorophenyl methacrylate (2,4-DMA) and vinyl acetate (VAc) were copolymerized with different feed ratios using dimethyl formamide (DMF) as a solvent and 2,2Ј-azobisisobutyronitrile (AIBN) as an initiator at 70°C. The copolymers were characterized by infrared (IR) spectroscopy. Copolymer compositions were determined by ultraviolet (UV) spectroscopy. The monomer reactivity ratios were evaluated by the Fineman-Ross method. Average molecular weight and polydispersity index were determined by gel permeation chromatography (GPC), and the intrinsic viscosities of polymers were also discussed. Thermogravimetric analyses of polymers were carried out under a nitrogen atmosphere. The homo-and copolymers were tested for their antimicrobial activity against selected microorganisms.

Low molecular weight poly(ether ketone)s were synthesized from phenol, 1,4-phenylenedioxy diacetylchloride, chloroacetylchloride, and dichloroalkanes [1,2dichloroethane and dichloromethane] by a Friedel-Crafts reaction with anhydrous aluminum chloride as a catalyst and carbon disulfide as a solvent. The conditions for the preparation of the poly(ether ketone)s and the chlorine contents obtained with the Carius method were examined, and a reaction scheme for each resin was established. The molecular weights and polydispersities of the resins were obtained by gel permeation chromatography. The polyketones were characterized by IR spectroscopy. The characteristic frequencies due to different functional groups were assigned. The thermal properties of the resins were studied with thermogravimetry and differential scanning calorimetry. The characteristic temperatures of thermal degradation for the poly(ether ketone)s were evaluated with thermogravimetric analysis. The kinetic parameters for the decomposition reactions of the resins were obtained with Broido and Doyle's method, and the heats of fusion were obtained from differential scanning calorimetry thermograms. The polyketones were thermally stable up to 200°C. All the polyketones were tested for their microbial properties against bacteria, fungi, and yeast. The effect of poly(ether ketone)s on the growth of these microorganisms was investigated, and the polyketones were found to inhibit the growth of the microorganisms to a considerable extent.

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Object. Intracranial atherosclerotic disease (ICAD) carries a high risk of stroke. Evaluation of ICAD has focused on assessing the absolute degree of stenosis, although plaque morphology has recently demonstrated increasing relevance. The authors provide the first report of the use of ultra-high-resolution C-arm cone-beam CT angiography (CBCT-A) in the evaluation of vessel stenosis as well as plaque morphology.Methods. Between August 2009 and July 2012, CBCT-A was used in all patients with ICAD who underwent catheter-based angiography at the authors' institution (n = 18). Lesions were evaluated for maximum degree of stenosis as well as plaque morphological characteristics (ulcerated, calcified, dissected, or spiculated) via digital subtraction angiography (DSA), 3D-rotational angiography (3DRA), and CBCT-A. The different imaging modalities were compared in their assessment of absolute stenosis as well as their ability to resolve different plaque morphologies.Results. Lesions were found to have similar degrees of stenosis when utilizing CBCT-A compared with 3DRA, but both 3DRA and CBCT-A differed from DSA in their assessment of the absolute degree of stenosis. CBCT-A provided the most detailed resolution of plaque morphology, identifying a new plaque characteristic in 61% of patients (n = 11) when compared with DSA and 50% (n = 9) when compared with 3DRA. CBCT-A identified all lesion characteristics visualized on DSA and 3DRA.Conclusions. CBCT-A provides detailed spatial resolution of plaque morphology and may add to DSA and 3DRA in the evaluation of ICAD. Further prospective study is warranted to determine any benefit CBCTA-A may provide in clinical decision making and risk stratification over existing conventional imaging modalities. This article contains some figures that are displayed in color on line but in black-and-white in the print edition. M. G. Safain et al. 442J Neurosurg / Volume 121 / August 2014 cranial stent placement during aneurysm treatment, 20,22 and delineate cerebral 15,16 and spinal arteriovenous malformations.1 Furthermore, CBCT-A has since been shown to have excellent spatial resolution of the intracranial vasculature, including the ability to resolve submillimeter objects such as stent struts measuring 50-70 µm. 13Despite these uses of CBCT-A in evaluation of intracranial vessels, its utility in determining stenosis and plaque morphology in ICAD has not been previously evaluated.Given the high spatial resolution provided by CBCT-A, we have, since August 2009, obtained imaging studies in all patients undergoing catheter-based angiography for ICAD using this modality, in addition to contemporaneous standard DSA and 3DRA. We sought here to compare and quantify the resolution of CBCT-A compared with 3DRA as well as DSA in the evaluation of ICAD. We present the initial report of additional plaque characteristics identified by CBCT-A in patients with ICAD. Methods Case SelectionDuring the study time period of August 2009 to July 2012, all patients undergoing catheter-based angiography for the ...

Copolymers of monomers 2,4-dichlorophenyl methacrylate (2,4-DMA) and methyl methacrylate (MMA) were synthesized with different monomer feed ratios using toluene as a solvent and 2,2Ј-azobisisobutyronitrile (AIBN) as an initiator at 70°C. The copolymers were characterized by IR-spectroscopy, and copolymer composition was determined with UV-spectroscopy. The linearization method of Fineman-Ross was employed to obtain the monomer reactivity ratios. The molecular weights and polydispersity indexes were determined by gel permeation chromatography (GPC). Thermogravimetric analyses of polymers were carried out in nitrogen atmosphere. The homoand copolymers were tested for their antimicrobial properties against selected microorganisms.