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As chest x rays involve risks of patients falling, radiologic technologists (technologists) commonly assist patients, and as the assistance takes place near the patients, the eye lenses of the technologists are exposed to radiation. The recommendations of the International Commission on Radiological Protection suggest that the risk of developing cataracts due to lens exposure is high, and this makes it necessary to reduce and minimize the exposure. The present study investigated the positions of technologists assisting patients that will minimize exposure of the eye lens to radiation. The results showed that it is possible to reduce the exposure by assisting from the following positions: 50% at the sides rather than diagonally behind, 10% at the right side of the patient rather than the left and 40% at 250 mm away from the patient. The maximum reduction with radiation protection glasses was 54% with 0.07 mmPb and 72% with 0.88 mmPb. [ABSTRACT FROM AUTHOR]

In coronary angiography (CAG) and percutaneous coronary intervention (PCI), it is important for radiological technologists to optimize the balance between radiation dose and image quality for physicians to be able to perform CAG and PCI most effectively. Evaluation of image processing is necessary to ensure that technologists can optimally adjust image quality for clinical use to the extent that physicians require. However, few phantoms are available for evaluating fluoroscopic image processing, and this makes it necessary to adjust image quality in clinical settings while utilizing the image processing according to the manufacturer's recommendations. In this study, we developed a dynamic phantom that mimics a pulsating coronary artery for use in image quality analysis of moving images. We also examined whether processed images (image lag) can be physically analyzed. Two issues require special attention in creating a new phantom: establishing the exact position of the simulated blood vessel in the phantom, and providing good reproducibility. The study used the rotational motion of a disk to generate images, with a circular simulated blood vessel on the rotating acrylic disk, with the center of the simulated blood vessel shifted from the center of the acrylic disk. This enabled the reproduction of translational motion of the simulated blood vessel. As a result, because this phantom has signals and afterimages at the same position (of a simulated blood vessel), a quantitative evaluation of the afterimages became possible. In the evaluation of the image processing with the angiograph, it was shown that evaluations of image lag which are typically performed in clinical settings can be performed with the dynamic blood vessel phantom. [ABSTRACT FROM AUTHOR]

The article focuses on a study which explores the impact of a metal artifact reduction (MAR) algorithm with the use of 1D linear interpolation on cone-beam CT (CBCT). It discusses the use of 1D linear interpolation in performing phantom and clinical qualitative studies with and without MAR application. Information about endovascular treatment (EVT) for cerebral aneurysms is presented.

Block copolymerization of plural types of monomers offers a new opportunity for the preparation of a variety of multifunctional polymers. Poly4diphenylaminostyrene PDASpoly9vinylanthracene PVAN binary block copolymer PDASPVAN was synthesized by living anionic polymerization using the benzyllithiumN,N,N′,N′tetramethylethylenediamine system. The photoluminescence emission of PDASPVAN was enhanced by the fluorescence resonance energy transfer from PDAS block to PVAN block in PDASPVAN. The hole drift mobility of the copolymer was controllable by the amount of triphenylamino groups in the polymer chain. The optical and electrical properties of PDASPVAN were adjustable through the polymer chain structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [ABSTRACT FROM AUTHOR]

Abstract  Hydrate effects on the conformations of ethylene oxide oligomers (EO-x, x = 1–8 mers) were examined using quantum chemical calculations (QCC). Conformational analyses were carried out by RHF/6-31G. The models were constructed by locating a water molecule to each ether–oxygen in the structures optimized for non-hydrate oligomers. Hydrate ratio, h (h = H2Omol/Omol in oligomer), was set from 0 to 1.0. The six type conformations with repeated units of O–C, C–C and C–O bonds were examined. Conformational energy, E c (HF), was calculated as difference between the energy of oligomer with water molecules and that of non-hydrogen and/or hydrogen bonding water molecules. Hydrate energies for each conformer, ∆μ h (kcal/m.u., based on E c in non-hydrate state), were negative and linearly decreased with the increase of h values, and such effects with the increase of h values were weaken with increasing x values. These results were consistent with our previous results calculated using the permittivity, ε (ε = 0–80.1), by QCC. In non-hydrate (h = 0), the (ttt) x conformers were the most stable independent of x. However, in hydrate states (h = 0.44–0.67), the (tg+t) x conformers were the most stable independent of x values, and in h = 1, the (tg+t)8 conformer (8-mer) was most stable [∆E c(g) = −1.3 kcal/m.u., ∆E c(g): energy difference between a given oligomer and the (ttt) x oligomer]. These results supported the experimental those based on NMR analyses using dimethoxyethane and triglyme solutions. Molecular lengths (l) of (tg+t) x , (tg+g−) x and (g+g+g+) x conformers having higher x values significantly decreased with increasing h values. Such contraction with hydration, however, was independent of ΔE c(g) values of each conformer. [ABSTRACT FROM AUTHOR]

Summary  Conformational analyses using quantum chemical calculations were carried out for 1- to 4-mers of ethylene oxide (EO) and ethylene imine (EI) oligomer models (EO-x and EI-x, x = 1 - 4) in the liquid phase using four solvents (permittivity: ε = 2.0 ~80.1). The results were compared against those obtained in the gaseous phase. The calculations involved either RHF/6-31+G(d,p) or B3LYP/6-31G(d) // SCRF/IPCM, based on the observed and calculated results for the energy difference between trans- and cis-dichloroethane. The conformations repeated for a unit of X-C, C-C and C-X bonds (X: O or N) were examined. For both oligomers, the energies of every conformer decreased with increasing ε values, and were linear against the Kirkwood function (Kf = (ε-1)/(2ε+1)). For the EO oligomers, the (ttt)x conformer was most stable in the gaseous phase. In liquid phases, however, the preference for the gauche-conformation (gauche preference) of the C-C bonds increased with higher values of ε. In the case of EO-3, the (tg+t)x conformer was most stable above an ε value of 8.9, which were in good agreement with those observed for triglyme solutions using NMR analysis. For the EI oligomers, the (tg+t)x conformer was most stable in either gaseous or liquid phase, and the gauche preference of the C-C bonds in both phases were comparable. These results were in good agreement with those observed for di-MEDA solutions using NMR analysis. It was estimated that such small solvent effects on gauche preferences of the EI oligomers result in weakening for hydrogen bonds (NH-N) of neighboring imino groups by solvents. [ABSTRACT FROM AUTHOR]

Polymers having 2,5‐diphenyl‐1,3,4‐oxadiazole (BCO) or anthracene (BCA) as an electron transport unit and N,N′‐diphenyl‐N,N′‐bis(4‐butylphenyl)‐benzidine (BTPD) as a hole transport unit were prepared by condensation polymerization using Friedel–Crafts reaction. It was found that BCO was less reactive than BCA. The low reactivity of the BCO monomer can be explained by the oxygen atom in the oxadiazole unit, which acts as a Lewis base and reduces the activity of the catalyst. The redox behavior measured by cyclic voltammetry showed for both BTPD‐BCO and BTPD‐BCA almost the same oxidation potential. In addition, the BTPD‐BCO also exhibited a reduction peak. Hole and electron drifts mobility of the polymers were measured by the time‐of‐flight method. The hole drift mobility of both BTPD‐BCO and BTPD‐BCA was 7.4 × 10−5 cm2 V−1 s−1. The electron drift mobilities of BTPD‐BCO and BTPD‐BCA were 6.5 × 10−5 cm2 V−1 s−1 and 5.2 × 10−6 cm2 V−1 s−1, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3083–3089, 2007 [ABSTRACT FROM AUTHOR]

The reactivity of three types of quinones (3,4,5,6?tetrachloro?1,2?(o?)?benzoquinone (TOQ), 2,3?dichloro?5,6?dicyano?1,4?benzoquinone (DDQ), and 2,3,5,6,?tetrachloro?1,4?(p?)?benzoquinone (TCQ)) was examined for the dehydrogenation of poly(1,3?cycohexadiene) (PCHD) composed of 1,2?cyclohexadiene and 1,4?cyclohexadiene units. The order of reactivity was TOQ > DDQ > TCQ. The steric hindrance of C=O groups in the quinones appeared to be an important factor in determining their reactivity. DDQ was found to be an appropriate dehydrogenation reagent for PCHD. The reactivity of TCQ was considerably low for PCHD containing 1,2?cyclohexadiene units. The reactivity of TOQ was too high and side reactions occurred, causing the formation of structural defects. Copyright © 2007 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Chemical composition and its distribution of styrene (St)-ethyl acrylate (EA) copolymers synthesized by emulsion copolymerization under different monomer ratios and polymerization conditions were examined by 1H-NMR and high-performance liquid chromatography (HPLC), respectively, and compared with those of bulk copolymers. It was newly found that the chemical composition of copolymer at early stage is affected by the concentration of emulsifier (SDS, sodium dodecyl sulfate) and monomer/water ratio, and is almost independent of the concentration of initiator or polymerization temperature. The EA fraction decreased with the increase of SDS concentration and converged to the value calculated using distribution factor (fd) when SDS concentration was extrapolated to zero. These results indicate that the EA fraction in micelle decreased compared to the expected value from fd due to the interaction of EA monomer with emulsifier. From HPLC, it was found that each copolymer showed a sharp single peak at an early stage of polymerization indicating that no homopolymer or copolymer with different composition was produced. [ABSTRACT FROM AUTHOR]