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Several detectors have been developed to measure radiation doses during radiotherapy. However, most detectors are not flexible. Consequently, the airgaps between the patient surface and detector could reduce the measurement accuracy. Thus, this study proposes a dose measurement system based on a flexible copper indium gallium selenide (CIGS) solar cell. Our system comprises a customized CIGS solar cell (with a size 10 × 10 cm2 and thickness 0.33 mm), voltage amplifier, data acquisition module, and laptop with in-house software. In the study, the dosimetric characteristics, such as dose linearity, dose rate independence, energy independence, and field size output, of the dose measurement system in therapeutic X-ray radiation were quantified. For dose linearity, the slope of the linear fitted curve and the R-square value were 1.00 and 0.9999, respectively. The differences in the measured signals according to changes in the dose rates and photon energies were <2% and <3%, respectively. The field size output measured using our system exhibited a substantial increase as the field size increased, contrary to that measured using the ion chamber/film. Our findings demonstrate that our system has good dosimetric characteristics as a flexible in vivo dosimeter. Furthermore, the size and shape of the solar cell can be easily customized, which is an advantage over other flexible dosimeters based on an a-Si solar cell. [ABSTRACT FROM AUTHOR]

This study introduces and evaluates respiratory-correlated four-dimensional (4D) inverse geometry computed tomography (IGCT). The projection data of the IGCT were acquired in a single gantry rotation over 120 s. Three virtual phantoms—static Defrise, 4D Shepp–Logan, and 4D extended cardiac-torso (XCAT)—were used to obtain projection data for the IGCT and cone-beam computed tomography (CBCT). The projection acquisition parameters were determined to eliminate vacancies in the Radon space for an accurate rebinning process. Phase-based sorting was conducted within 10 phase bins, and the sorted projection data were binned into a cone beam geometry. Finally, Feldkamp–Davis–Kress reconstruction was conducted independently at each phase. The reconstructed images were compared using the structural similarity index measure (SSIM) and root mean square error (RMSE). The vertical profile of the Defrise reconstruction image was uniform, and the cone beam artefact was reduced in the IGCT image. Under an ideal projection acquisition condition, the mean coronal plane SSIMs of the Shepp–Logan and 4D XCAT phantoms were 0.899 and 0.706, respectively, which were higher than those of the CBCT (0.784 and 0.623, respectively). Similarly, the mean RMSEs of the coronal plane IGCT (0.036 and 0.158) exhibited an improvement over those of the CBCT (0.165 and 0.261, respectively). The mean standard deviations of the SSIM and RMSE were lower for IGCT than for CBCT. In particular, the SSIM and RMSE of the sagittal and coronal planes of the Shepp–Logan IGCT images were stable in all phase bins; however, those of the CBCT changed depending on the phase bins. Poor image quality was observed for IGCT under inappropriate conditions. This was caused by a vacancy in the Radon space, owing to an inappropriate scan setting. Overall, the proposed 4D IGCT exhibited better image quality than conventional CBCT. [ABSTRACT FROM AUTHOR]

In the quest to synthesize compounds that are uniquely optimized for fighting each individual target disease, the importance of developing a new methodology for the bioconjugation of compounds with different functional groups or biological activities cannot be overemphasized. This study investigates two novel methods for click reaction: coupling a molecule with three functional compounds by repetitive copper(I) catalyzed azide/alkyne 1,3‐dipolar cycloadditions. Method A uses three copper(I) catalyzed azide/alkyne 1,3‐dipolar cycloadditions in series. Method B uses two copper(I) catalyzed azide/alkyne 1,3‐dipolar cycloadditions and one conjugation reaction of amine and isothiocyanate. [ABSTRACT FROM AUTHOR]

Purpose: Deformable lung phantoms have been proposed to investigate four‐dimensional (4D) imaging and radiotherapy delivery techniques. However, most phantoms mimic only the lung and tumor without pulmonary airways. The purpose of this study was to develop a reproducible, deformable lung phantom with three‐dimensional (3D)‐printed airways. Methods: The phantom consists of: (a) 3D‐printed flexible airways, (b) flexible polyurethane foam infused with iodinated contrast agents, and (c) a motion platform. The airways were simulated using publicly available breath‐hold computed tomography (CT) image datasets of a human lung through airway segmentation, computer‐aided design modeling, and 3D printing with a rubber‐like material. The lung was simulated by pouring liquid expanding foam into a mold with the 3D‐printed airways attached. Iodinated contrast agents were infused into the lung phantom to emulate the density of the human lung. The lung/airways phantom was integrated into our previously developed motion platform, which allows for compression and decompression of the phantom in the superior–inferior direction. We quantified the reproducibility of the density (lung), motion/deformation (lung and airways), and position (airways) using breath‐hold CT scans (with the phantom compressed and decompressed) repeated every two weeks over a 2‐month period as well as 4D CT scans (with the phantom continuously compressed and decompressed) repeated twice over four weeks. The density reproducibility was quantified with a difference image (created by subtracting the rigidly registered baseline and the repeated images) in each of the compressed and decompressed states. Reproducibility of the motion/deformation was evaluated by comparing the baseline displacement vector fields (DVFs) derived from deformable image registration (DIR) between the compressed and decompressed phantom CT images with those of repeated scans and calculating the difference in the displacement vectors. Reproducibility of the airway position was quantified based on DIR between the baseline and repeated images. Results: For the breath‐hold CT scans, the mean difference in lung density between baseline and week 8 was −1.3 (standard deviation 33.5) Hounsfield unit (HU) in the compressed state and 0.4 (36.8) HU in the decompressed state, while large local differences were observed around the high‐contrast structures (caused by small misalignments). By visual inspection, the DVFs (between the compressed and decompressed states) at baseline and last time point (week 8 for the breath‐hold CT scans) demonstrated a similar pattern. The mean lengths of displacement vector differences between baseline and week 8 were 0.5 (0.4) mm for the lung and 0.3 (0.2) mm for the airways. The mean airway displacements between baseline and week 8 were 0.6 (0.5) mm in the compressed state and 0.6 (0.4) mm in the decompressed state. We also observed similar results for the 4D CT scans (week 0 vs week 4) as well as for the breath‐hold CT scans at other time points (week 0 vs weeks 2, 4, and 6). Conclusions: We have developed a deformable lung phantom with 3D‐printed airways based on a human lung CT image. Our findings indicate reproducible density, motion/deformation, and position. This phantom is based on widely available materials and technology, which represents advantages over other deformable phantoms. [ABSTRACT FROM AUTHOR]

To establish the relation between optimum interlayer distance for hydrogen storage and electrical conductance, we measured the electrical conductance ( G ) of 3-dimensional graphene oxide (GOA) depending on high H 2 pressure, from vacuum to 20 bar. The GOA was synthesized using diaminoalkanes with two lengths of alkyl chains, and the interlayer distance of GOA was modulated by thermal annealing. A decrease in G was observed as the H 2 pressure increased. The maximum variation in G was observed at 7.0 Å of interlayer distance. When the interlayer distance-dependent H 2 uptake was considered, we confirmed that the maximum variation in G as well as optimum H 2 uptake occurred at the same interlayer distance, 7.0 Å. The variation in G due to H 2 exposure provides understanding about the behavior of hydrogen molecules on these materials and on the modulation of the electronic structure of the materials. [ABSTRACT FROM AUTHOR]

Divergent functionalized 8-methoxyquinaldines were synthesized via regioselective debromination, 1,3-bromine shift process, aromatization with treatment of a strong base, nucleophilic substitution reaction at the C7 position using amines and cyanide as a nucleophile in the absence of a metal source and a catalyst from an unusual electrophilic aromatic addition (Ad E Ar) reaction products 7 and 8 . In addition, quinaldine-7,8-dione was prepared by presence of CAN (ceric ammonium nitrate) in AcOH and H 2 O for 10 min at room temperature from N -(alkylamino)-8-methoxyquinalidines. During the Ad E Ar reaction, new stereoselective dearomatized addition products were generated via discriminative reaction routes depending on the methoxy and bromine occupancy position. The Ad E Ar reaction not only allowed for the functionalization of electron rich-fused heterocyclic arenes, but also provided a new synthetic route to an alternative mechanism for electrophilic aromatic substitution reactions. [ABSTRACT FROM AUTHOR]

Recently, we reported n -type graphene can be achieved simply using H 2 molecules. It was understood by the attachment of hydrogen atoms dissociated on the surface of graphene. However, the amount of attached hydrogen has not been yet investigated. Here, we show the possibility of the formation of C H bonds due to the H 2 exposure theoretically and the mass of the attached hydrogen atoms on graphene experimentally. The amount of the attached hydrogen atoms has been measured by a quartz crystal microbalance (QCM). After exposure of a multilayer graphene (MLG) to 20 bar of H 2 pressure at 353 K for 20 h, the resonance frequency (RF) of QCM decreased. It indicates that the mass of the MLG increases. On the basis of the RF variation, we concluded that the hydrogen atoms were bonded to 3.84% of carbon atoms in the MLG. In order to confirm the C H bonding of MLG, Raman spectroscopy was performed before and after exposure to H 2 pressure. On exposure, the D peak developed and the peak for 2-D graphite in 2D band increased. The experimental results and theoretical calculation demonstrate that the H 2 molecules on the surface of the graphene are dissociated and that some of dissociated H atoms are attached on graphene. [ABSTRACT FROM AUTHOR]

The article presents chemical equations for article "Versatile Functionalization of Electron Rich-Fused Heterocyclic Arenes via Electrophilic Aromatic Addition Reaction and Their Applications" by K. S. Jang and others, published in "Tetrahedron" in 2016.

Background: The present study aimed to propose a new foetal shielding device for pregnant cancer patients to reduce the foetal dose associated with treatment techniques using multiple gantry angles, such as intensity-modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT).Methods: Three shielding structures were designed to minimise the scattered and leaked radiation from various gantry angles and radiation scattering within the patient. The base-plate part that can be placed on the treatment couch was designed to reduce the scattered and leaked radiation generated at gantry angles located near 180°. A body shielding part that can cover the lower chest and abdomen was designed, and a neck-shielding structure was added to reduce the internal and external radiation scattering from the treatment area. Evaluation plans were generated to assess the foetal dose reduction by the foetal shielding device in terms of the shielding material thickness, distance from the field edge, and shielding component using the flattened 6 MV photon beam (6MV) and flattening filter-free 6 MV photon beam (6MV-FFF). In addition, the effectiveness of the foetal shielding device was evaluated in a pregnant brain tumour patient.Results: The shielding material consisting of three parts was placed on frames composed of four arch shapes with a vertical curved structure, connection bar at the top position, and base plate. Each shielding part resulted in reductions in the radiation dose according to the treatment technique, as the thickness of the shielding material increased and the foetal dose decreased. In addition, a foetal dose reduction of approximately 50% was confirmed at 50 cm from the field edge by using the designed shielding device in most delivery techniques. In patients, the newly designed shielding structures can effectively eliminate up to about 49% of the foetal dose generated from various gantry angles used in VMAT or IMRT.Conclusions: We designed a foetal shielding device consisting of three parts to effectively reduce the dose delivered to the foetus, and evaluated the device with various treatment techniques for a pregnant patient with brain tumour. The foetal shielding device shielded the scattered/leaked radiation from the treatment machine, and also effectively reduced internal scattering from the treatment area in the patient. [ABSTRACT FROM AUTHOR]

Abstract: A convenient and mild synthetic method of synthesizing benzofuran from various 2-(cyanomethyl)phenyl carbonyl compounds under reduced oxygen conditions is reported. Nine C-2 substituted benzofurans were synthesized at 52–89%. [Copyright &y& Elsevier]

Background: In intensity modulated radiation therapy (IMRT) quality assurance (QA), evaluation of QA result using a pass/non-pass strategy under an acceptance criterion often suffers from lack of information on how good the plan is in absolute manner. In this study, we suggested adding an index system, previously developed for dose painting technique, to current IMRT QA process for better understanding of QA result.Methods: The index system consists of three indices, index of achievement (IOA), index of hotness (IOH) and index of coldness (IOC). As indicated by its name, IOA does measure the level of agreement. IOH and IOC, on the other hand, measure the magnitude of overdose and underdose, respectively. A systematic analysis was performed with three 1-dimensional hypothetical dose distributions to investigate the characteristics of the index system. The feasibility of the system was also assessed with clinical volumetric modulated arc therapy (VMAT) QA cases from 8 head & neck and 5 prostate patients. In both simulation studies, certain amount of errors was intentionally induced to each dose distribution. Furthermore, we applied the proposed system to compare calculated with actual measured data for a total of 60 patients (30 head & neck and 30 prostate cases). QA analysis was made using both the index system and gamma method, and results were compared.Results: While the gamma evaluation showed limited sensitivity in evaluating QA result depending on the level of tolerance criteria used, the proposed indices tended to better distinguish plans in terms of the amount of errors. Hotness and coldness of prescribed dose in the plan could be evaluated quantitatively by the indices.Conclusions: The proposed index system provides information with which IMRT QA result would be better evaluated, especially when gamma pass rates are identical or similar among multiple plans. In addition, the independency of the index system on acceptance criteria would help making clear communications among readers of published articles and researchers in multi-institutional studies. [ABSTRACT FROM AUTHOR]

A convenient and mild in situ two-step method for the synthesis of the title compounds is reported from easily preparable starting materials. [ABSTRACT FROM AUTHOR]