Do-Youn Park

Catalytic degradation of polypropylene: effect of dealumination of clinoptilolite catalyst

The performance of several differently treated clinoptilolite zeolites in the degradation of polypropylene was investigated in this study. The composition of degradation products, especially liquid fractions resulted over studied catalysts, was compared to understand the role of catalysts. The degradation was carried out in a semi-batch reactor with a mixture of polypropylene and catalysts at 400 °C. The liquid products from the catalytic degradation of polypropylene are distributed in a narrower range of carbon numbers compared with those obtained by thermal degradation. With dealuminated clinoptilolite catalysts, the distribution of liquid products shifted to lower numbers of carbon atoms due to the increase of the portion of medium acid sites and micropore diameter. The increase of temperature accelerated the cracking of intermediately degraded fragments to lower hydrocarbons.

Suppression of distant pulmonary metastasis of MDA-MB 435 human breast carcinoma established in mammary fat pads of nude mice by retroviral-mediated TIMP-2 gene transfer.

Previous studies have shown that TIMP‐2 overexpression is a useful therapeutic tool for inhibiting tumor growth and invasion in animals. However, it has not been reported whether genetic manipulation for TIMP‐2 overexpression can induce an inhibitory effect on spontaneous metastasis from the primary tumor site to other organs such as lungs or lymph nodes in an animal model.

Comparison of level of NKG2D ligands between normal and tumor tissue using multiplex RT-PCR.

The abilities of NKG2D ligands to specifically mark stressed or transformed cells and activate NK cells suggest the possibility that the expression levels of NKG2D ligands in cancers may be helpful to predict the efficacy of NK cell-based cancer immunotherapy. Therefore, a multiplex RT-PCR was developed and used for rapid and simultaneous analysis of the expression level of NKG2D ligands in cancer cells and tissues. With total RNAs isolated from various cancer cell lines, the multiplex RT-PCR revealed various expression patterns of NKG2D ligands. With total tissue RNAs, the gastrointestinal tumors showed consistently increased NKG2D ligands, compared with adjacent normal tissues. However, NKG2D ligands were not always consistently increased in tumor tissues and expression patterns of NKG2D ligands were heterogeneous between patients, especially in breast and lung cancers. In addition, expression patterns of NKG2D ligands were very similar between various paired primary and their multidrug-resistant/metastatic cells, except MCF-7 sublines. These results demonstrated that the multiplex RT-PCR might be a useful diagnostics to detect the expression levels of NKG2D ligands in tissues as well as cells, and suggested that the gastrointestinal tumors might be good candidates for NK cell-based cancer immunotherapy, since it showed significantly higher levels of NKG2D ligands than adjacent normal tissues.

Synthesis and application of terpolymer bearing cyclic carbonate and cinnamoyl groups

Abstract We propose the syntheses of photopolymer with pendant cinnamic ester and cyclic carbonate groups by the addition reaction of poly(glycidyl methacrylate-co-styrene) with CO2 and then with cinnamoyl chloride. Quaternary ammonium salts showed good catalytic activity for this synthesis. Photochemical reaction experiments revealed that terpolymer having cinnamate and cyclic carbonate groups has good photosensitivity, even in the absence of sensitizer. In order to expand the application of the obtained terpolymer, polymer blends with poly(methyl methacrylate) were prepared. Differential scanning calorimetry and optical clarity tests showed that the blends were miscible over the whole composition ranges.

Highly active mesoporous chromium silicate catalysts in side-chain oxidation of alkylaromatics.

We approach a green method in the production of alkylaromatic ketones over hexagonally ordered mesoporous CrSBA-15 catalysts, which were used, in green routes, in the liquid-phase oxidation of alkylaromatics. A promising chemical treatment method was used with ammonium acetate solution to remove the toxic nature of non-framework chromium oxides deposited on the surface of calcined CrSBA-15(8), and the obtained green mesoporous CrSBA-15(8) catalyst was used to find its catalytic activity while the recyclability of mesoporous CrSBA-15 catalysts was also studied. Particularly, the mesoporous CrSBA-15 catalysts synthesized with a variety of chromium contents were extensively used in the production of acetophenone (AP=O) with various reaction parameters. On the basis of all catalytic results, the mesoporous CrSBA-15(8) catalyst produced a higher selectivity of alkylaromatic ketones (76-100%) as compared to other CrSBA-15 catalysts and was found to be a highly active, recyclable and promising heterogeneous catalyst for selective synthesis of alkylaromatic ketones.

Selective synthesis of 6,8-di-t-butylated flavan over Zn–Al containing mesoporous silica catalysts

We demonstrate a much green synthesis method for highly selective synthesis of 6,8-di-t-butylated flavan (6,8-DTBF) by liquid phase alkylation of 2,4-di-t-butylphenol (2,4-DTBP) with cinnamyl alcohol (Cin-OH) over mesoporous Zn-Al-MCM-41 catalysts synthesized under direct basic hydrothermal method. The main alkylated product, 6,8-DTBF is importantly used as an intermediate in the manufacture of biosynthetic organic compounds. The recyclable mesoporous Zn-Al-MCM-41 catalysts have also been reused in this reaction to study their catalytic activities. The influences of various reaction parameters such as temperature, time, ratios of reactant (2,4-DTBP-to-Cin-OH) have been extensively investigated for the synthesis of 6,8-DTBF. In addition, dimethyl sulfoxide (DMSO) has also been used as a solvent in this catalytic reaction. The mesoporous Zn-Al-MCM-41(75) gives excellent catalytic activity with 6,8-DTBF selectivity (86.0%) and 2,4-DTBP conversion (63.1%), and these catalytic results have also compared with that obtained using other mesoporous and microporous catalysts. On the basis of catalytic activity obtained by using the all catalysts, the Zn-Al-MCM-41(75) catalyst is found to be a highly active, recyclable and eco-friendly heterogeneous catalyst in the liquid-phase alkylation of 2,4-DTBP.

Adenocarcinoma with sarcomatous dedifferentiation arising from mature cystic teratoma of the anterior mediastinum

Mediastinal teratoma with malignant transformation (TMT) is a very rare condition. A 44-year-old man presented with a large cystic mass of the anterior mediastinum. The tumor was surgically removed. The cystic mass was well demarcated, with an irregularly thickened wall. Histologically, the cystic wall was mainly lined by non-ciliated columnar epithelium and focally by squamous epithelium. A nodular part of the cystic wall revealed well-differentiated adenocarcinoma composed of tubulopapillary structures. Deep in the nodular tissue, neoplastic glands merged into undifferentiated sarcomatous cells. Immunohistochemically, CK7, CK19, and smad-4 were strongly and diffusely positive in adenocarcinoma. CD10 was focally positive on the luminal surface of the glands, and MUC5AC was also focally positive. TTF-1, cdx-2, and CK20 were negative in the adenocarinoma. Sarcomatous area showed diffuse strong positivity for vimentin, but was negative for the aforementioned epithelial markers. About 10 months postoperatively, a left pleural effusion had developed with multiple pleural nodules on computed tomography scan of the chest. The cytologic diagnosis from pleural fluid was metastatic adenocarcinoma. To our knowledge, in the English literature, this is the first case of adenocarcinoma with sarcomatous transformation that has developed in a mature cystic teratoma of the mediastinum and shows pleural metastasis.

SU‐E‐I‐17: Comparison of Two Novel Algorithms for the Modulation Transfer Function of CT Using a Simple Cylindrical Phantom

PURPOSE To compare and analyze two novel algorithms for the assessment of modulation transfer functions (MTFs) of computed tomography (CT) systems using a simple acrylic cylindrical phantom METHOD AND MATERIALS: Images of the acrylic cylindrical phantom were acquired by a GE LightSpeed 16 RT (GE Healthcare, Milwaukee, WI) using 120 kVp, 330 mA, 2.5 mm slice thickness, 10 cm field-of view (FOV), four reconstruction kernels (e.g. standard, soft, detail, bone, and lung). Two different algorithms were used to analyze images for MTF assessment. First, Richard et al. suggested a task-based MTF assessment method through an edge spread function (ESF) which described pixel intensities as a function of distance from the center. The MTF was obtained as the absolute value of Fourier transform of the differentiated ESF. Second, Ohkubo et al. devised an effective method to determine the point spread function (PSF) of CT system accompanied with verification. The line spread function (LSF), which was the one-dimensional integration of the PSF, was used to obtain the MTF. We validated the reliability of two above-mentioned methods through the comparison with a conventional method using a thin tungsten wire phantom. RESULTS The measured MTFs by two methods were mostly similar each other for standard, soft, and detail kernels. In 0.6 lp/mm, the MTF difference between two methods were 0.012(standard), 0.004(soft), and 0.037(detail). They also coincided with the MTF by the conventional method well. However, there were considerable distinctions for bone and lung kernels containing edge enhancement that might cause undershoots near the peak of the LSF. CONCLUSIONS We compared two novel methods to assess task-based MTFs for clinical CT systems especially using a simple acrylic cylindrical phantom with high-convenience and low-cost, and validated them against a conventional method. This work can provide a practical solution to users for the quality assurance of CT.

Utility of the Equivalent Depth Concept for in-vivo Dosimetry With No Build-up on the Skin Using Glass Rod Dosimeter (GRD) : Preliminary Results

Therapeutic dose verification with in-vivo dosimetry is important in modern radiotherapy because of its high complexity and high precision. The conventional dosimeters, thermoluminescent dosimeter (TLD) or dosimetric films for examples, has been widely used. However, they require a great care because of their complicated calibration and readout procedures. Furthermore, use of build-up involves change of delivered dose distribution. We tried to use a radiophotoluminescent glass rod dosimeter (GRD) system with no build-up on the skin. The equivalent depth concept for each effective field size and each incident beam angle was introduced to perform effective in-vivo dosimetry on the skin. As a preliminary result, we successfully obtained a equivalent depth table using 20 GRDs. We performed in-vivo dosimetry to verify the usefulness of this table in three patients, and found that there are deviations less than 5.0%. Finally, we found the possibility to perform effective in-vivo dosimetry with no build-up on the skin. The obtaining of a more precise equivalent depth table and more clinical verification will be our further works.

SU‐E‐J‐179: The Accurate Electron Density Image Containing Metal Prosthesises Through the Hybrid Sinogram for Tomotherapy: A Phantom Study

Purpose: To obtain the hybrid CT images, which have both the high contrast of kV‐CT and very low metal artifact of MV‐CT, for tomotherapy patients with metal prosthesisesMethods: We used a standard cheese phantom containing four metal inserts (copper, silver, tin, tungsten) to acquire a kV‐sinogram by a CT simulator and a MV‐CT image by Tomotherapy. The MV‐sinogram was acquired by the forward projection of the MV‐CT image using the geometry of kV‐CT system. Both sinograms were normalized with their total length of x‐ray attenuation and then were converted to the mean electron densities using corresponding calibration curves. The metal data in the MV‐sinogram were segmented using a given density threshold and transplanted to the kV‐sinogram row by row to acquire the normalized hybrid sinogram. The misalignment between metal data of two sinograms was corrected by mutual information technique. The hybrid CT image was finally obtained through de‐normalization and back‐projection procedures. For the experimental verification, film measurements were performed and analyzed using three head and neck treatment plans. Results: We found that the hybrid CT image of the cheese phantom containing four metal inserts has similar contrast and very low metal artifact compared to the kV‐CT image. Moreover, the metal densities on the hybrid CT‐image were accurate with the mean deviation of 3.3%. As the Result of film measurements, the average gamma pass rate of kV‐CT plan and hybrid‐CT plan were 93.7% and 96.5% with the criteria of 2%/2mm, and 67.1% and 81.4% with the criteria of 1%/1mm. Conclusions: This work indicated that the hybrid CT image can improve the accuracy of tomotherapy treatment plan with metal prosthesises without additional imaging dose. Our further study is to acquire and evaluate hybrid CT images from clinical kV‐sinograms and MV‐CT images.