• Journal of Veterinary Clinics
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• v.37 no.6
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• pp.350-354
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• 2020

Feline chronic lymphocytic leukemia (CLL) is a rare disease. Its diagnosis is not simple because of the absence of clinical signs and the presence of mature lymphocytosis. An 11-year-old female spayed Russian Blue cat was referred to the veterinary medical teaching hospital for lethargy, diarrhea, weight loss, and inappetence. Marked lymphocytic leukocytosis and a significantly increased number of small-to-intermediate-sized lymphocytes in the peripheral blood were found on hematological examination. The results of the feline leukemia virus and immunodeficiency virus test were negative. Further, mild splenomegaly was detected. Bone marrow aspirate analysis revealed mature lymphocytosis and a clonally rearranged T cell receptor gene with the polymerase chain reaction (PCR) for antigen receptor rearrangement assay. Flow cytometric immunophenotyping showed a homogeneous population of CD5+/CD21-T-cells in the peripheral blood and bone marrow. According to the results of the aforementioned examinations, CLL was diagnosed. Treatment was not initiated at the time of diagnosis because the clinical signs were mild and did not affect the quality of life. This report describes the clinical findings and use of advanced diagnostic tools such as molecular clonality analysis and immunophenotyping for the diagnosis of feline CLL.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.159-164
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• 1998

Polycarbosilane(PCS) as a SiC precursor was synthesized from the rearrangement reaction of polydimethysilane(PDMS) in an autoclave, which prepared by dehalocoupling reaction of dichlorodimethylsilane. After fractional precipitation into three fractions in n-hexane-methanol mixture, they were characterized by FT-IR, NMR, GPC, TGA/DSC and XRD, and compared with the commercial product. We found that the molecular weight distributions of the PCS depended on the reaction pressures, temperatures and the reaction times, and affected thermal property and ceramic yield of the polymer. The monodispersed PCS containing less amount of oligomers and nonsoluble products was prepared by reaction of PDMS at $420^{\circ}C$ for 10 hrs, and it also gave the greatest amount of medium molecular weight($M_n=4,000$) fraction.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.149-153
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• 2016

Breast cancer is the most common cancer in Iran. In the recent years an upward trend has been observed in the Iranian population. Early detection by molecular approaches may reduce breast cancer morbidity and mortality. We provided consultation to 3,782 women diagnosed with early onset breast cancer during the past 15 years (1999-2014). To establish a data set for BRCA gene alterations of the Iranian families at risk, two hundred and fifty four women who met our criteria were analyzed. A total number of 46 alterations including 18 variants with unknown clinical significance (39.1%), 18 missense mutations (39.1%), 7 Indels (15.2%) and 3 large rearrangement sequences (6%) were identified. Further scanning of affected families revealed that 49% of healthy relatives harbor identical causative mutations. This is the first report of comprehensive BRCA analysis in Iranian women with early onset breast cancer. Our findings provide valuable molecular data to support physicians as well as patients for the best decision making on disease management.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1470-1474
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• 2009

Thermal and photochemistry of methyl iodide ($CH_3I)\;adsorbed\;on\;D_2O$ ice film on Cu(111) at 100 K were studied using temperature-programmed desorption (TPD) time-of-flight mass spectrometry (TOF-MS), X-ray and ultraviolet photoelectron spectroscopies. On the basis of TPD, multilayer and monolayer $CH_3I$ molecules desorb from $D_2O$ ice layer at 120 and 130 K, respectively. Photo-irradiation at 100 K exhibits dramatic changes in the TPD and I $3d_{5/2}\;XPS\;of\;CH_3I$ on ice film, due to a dramatic dissociation of $CH_3I$. The dissociation is likely activated by solvated electrons transferred from the metal substrate during photo-irradiation. No other photo-initiated reaction products were found within our instrumental detection limit. During photo-irradiation, the $CH_3I$, $CH_3$ and I could be trapped (or solvated) in ice film by rearrangement (and self-diffusion) of water molecules. A newly appeared parent molecular desorption peak at 145 K is attributed to trapped $CH_3I$. In addition, the $CH_3$ and I may diffuse through ice and chemisorb on Cu(111), indicated by TPD and I $d_{5/2}$ XPS taken with photo-irradiation time, respectively. No molecular ejection was found during photo-irradiation at 100 K. The work functions for $CH_3I/Cu(111),\;D_2O/Cu(111)\;and\;CH_3I/D_2$O/Cu(111) were all measured to be about 3.9 eV, 1.0 eV downward shift from that of clean Cu(111).

• Composites Research
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• v.35 no.1
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• pp.23-30
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• 2022

Polycarbosilane(PCS) is an important precursor for melt-spinning the silicon carbide(SiC) fibers and manufacturing ceramics. The PCS is a metal-organic polymer precursor capable of producing continuous SiC fibers having excellent performance such as high-temperature resistance and oxidation resistance. The SiC fibers are manufactured through melt-spinning, stabilization, and heat treatment processes using the PCS manufactured by synthesis, purification, and control of the molecular structure. In this paper, we analyzed the effect of purification of unreacted substances and low molecular weight through solvent treatment of PCS and the effect of heat treatment at various temperatures change the polymerization and network rearrangement of PCS. Especially, we investigated the complex viscosity and structural arrangement of PCS precursors according to solvent treatment and heat treatment through the rheological properties.

• The Journal of the Korean Society for Microbiology
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• v.34 no.6
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• pp.519-532
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• 1999

Helicobacter pylori is a causative agent of type B gastritis and plays a central role in the pathogenesis of gastroduodenal ulcer and gastric cancer. To elucidate the host-parasite relationship of the H. pylori infection on the basis of molecular biology, we tried to evaluate the genomic diversity of H. pylori. An ordered overlapping bacterial artificial chromosome (BAC) library of a Korean isolate, H. pylori 51 was constructed to set up a genomic map. A circular physical map was constructed by aligning ApaI, NotI and SfiI-digested chromosomal DNA. When the physical map of H. pylori 51 was compared to that of unrelated strain, H. pylori 26695, completely different restriction patterns were shown. Fifteen known genes were mapped on the chromosome of H. pylori 51 and the genetic map was compared with those of strain 26695 and J99, of which the entire genomic sequences were reported. There were some variability in the gene location as well as gene order among three strains. For further analysis on the genomic diversity of H. pylori, when comparing the genomic structure of 150 H. pylori Korean isolates with one another, genomic macrodiversity of H. pylori was characterized by several features: whether or not susceptible to restriction digestion of the chromsome, variation in chromosomal restriction fingerprint and/or high frequency of gene rearrangement. We also examined the extent of allelic variation in nucleotide or deduced amino acid sequences at the individual gene level. fucT, cagA and vacA were confirmed to carry regions of high variation in nucleotide sequence among strains. The plasticity zone and strain-specific genes of H. pylori 51 were analyzed and compared with the former two genomic sequences. It should be noted that the H. pylori 51-specific sequences were dispersed on the chromosome, not congregated in the plasticity zone unlike J99- or 26695-specific genes, suggesting the high frequency of gene rearrangement in H. pylori genome. The genome of H. pylori 51 shows differences in the overall genomic organization, gene order, and even in the nucleotide sequences among the H. pylori strains, which are far greater than the differences reported on the genomic diversity of H. pylori.

• IMMUNE NETWORK
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• v.1 no.2
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• pp.104-108
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• 2001

Aging is a senescence and defined as a normal physiologic and structural alterations in almost all organ systems with age. As Leonard Hayflick, one of the first gerontologists to propose a theory of biologic aging, indicated that a theory of aging or longevity satisfies the changes of above conditions to be universal, progressive, intrinsic and deleterious. Although a number of theories have been proposed, it is now clear that cell aging (cell senescence) is multifactorial. No single mechanism can account for the many varied manifestations of biological aging. Many theories have been proposed in attempt to understand and explain the process of aging. Aging is effected in individual by genetic factors, diet, social conditions, and the occurrence of age-related diseases as diabetes, hypertension, and arthritis. It involves an endogenous molecular program of cellular senescence as well as continuous exposure throughout life to adverse exogenous influences, leading to progressive infringement on the cell's survivability so called wear and tear. So we could say the basic mechanism of aging depends on the irreversible and universal processes at cellular and molecular level. The immediate cause of these changes is probably an interference in the function of cell's macromolecules-DNA, RNA, and cell proteins-and in the flow of information between these macromolecules. The crucial questions, unanswered at present, concerns what causes these changes in truth. Common theories of aging are able to classify as followings for the easy comprehension. 1. Biological, 1) molecular theories - a. error theory, b. programmed aging theory, c. somatic mutation theory, d. transcription theory, e. run-out-of program theory, 2) cellular theories - a. wear and tear theory, b. cross-link theory, c. clinker theory, d. free radical theory, e. waste product theory, 3) system level theory-a. immunologic/autoimmune theory, 4) others - a. telomere theory, b. rate of living theory, c. stress theory, etc. Prevention of aging is theoretically depending on the cause or theory of aging. However no single theory is available and no definite method of delaying the aging process is possible by this moment. The most popular action is anti-oxidant therapy using vitamin E and C, melatonin and DHEA, etc. Another proposal for the reverse of life-span is TCP-17 and IL-16 administration from the mouse bone marrow B cell line study for the immunoglobulin VDJ rearrangement with RAG-1 and RAG-2. Recently conclusional suggestion for the extending of maximum life-span thought to be the calory restriction.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.36.2-36.2
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• 2009

Low dielectric materials have been great attention in the semiconductor industry to develop high performance interlayer dielectrics with low k for Cu interconnect technology. In our study, the dielectric properties of SiOC /SiO2 thin film derived from polyphenylcarbosilane were investigated as a potential interlayer dielectrics for Cu interconnect technology. Polyphenylcarbosilane was synthesized from thermal rearrangement of polymethylphenylsilane around $350^{\circ}C{\sim}430^{\circ}C$. Characterization of synthesized polyphenylcarbosilane was performed with 29Si, 13C, 1H NMR, FT-IR, TG, XRD, GPC and GC analysis. From FT-IR data, the band at 1035 cm-1 is very strong and assigned to CH2 bending vibration in Si-CH2-Si group, indicating the formation of the polyphenylcarbosilane. Number average of molecular weight (Mn) of the polyphenylcarbosilane synthesized at $400^{\circ}C$ for 6hwas 2, 500 and is easily soluble in organic solvent. SiOC/SiO2 thin film was fabricated on ton-type silicon wafer by spin coating using 30wt % polyphenylcarbosilane incyclohexane. Curing of the film was performed in the air up to $400^{\circ}C$ for 2h. The thickness of the film is ranged from $1{\mu}m$ to $1.7{\mu}m$. The dielectric constant was determined from the capacitance data obtained from metal/polyphenylcarbosilane/conductive Si MIM capacitors and show a dielectric constant as low as 2.5 without added porosity. The SiOC /SiO2 thin film derived from polyphenylcarbosilane shows promising application as an interlayer dielectrics for Cu interconnect technology.

• The Korean Journal of Cytopathology
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• v.10 no.2
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• pp.157-162
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• 1999

Primary non-Hodgkin's lymphoma of the lung is rare among extranodal lymphomas. The most common form is low grade B-cell type originated from the mucosa-associated lymphoid tissue (MALT) of the lung and primary peripheral T cell lymphoma of the lung is extremely rare. We recently experienced a case of fine needle aspiration cytology of primary peripheral T cell lymphoma of the lung in a 39-year-old male patient. The cytologic smears revealed some sheets of reactive epithelial cells, epithelioid histiocytes, and numerous polymorphous population of lymphoid cells composed of small and intermediate sized lymphoid cells and mature lymphocytes. Lymphoid cells were slightly larger than normal mature lymphocytes and showed significant irregularity of nuclear membrane. The internal nuclear structure was marked by chromatin clumping, clear parachromatin areas, and inconspicuous nucleoli. Histopathologically, atypical small lymphocytes infiltrated in the interstitium and alveolar sac. By the immunohistochemical study and molecular biologic study of gene rearrangement, the T cell clonality of atypical lymphoid cells was confirmed.

• Molecular & Cellular Toxicology
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• v.3 no.2
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• pp.137-144
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• 2007

The mechanism of cytotoxicity of doxifluridine, a prodrug fluorouracil (5-FU), has been ascribed to the misincorporation of fluoropyrimidine into RNA and DNA and to the inhibition of the nucleotide synthetic enzyme thymidylate synthase. Increased understanding of the mechanism of 5-FU has led to the development of strategies that increases its anticancer activity or predicts its sensitivity to patients. Using GeneChip?? Rhesus Macaque Genome arrays, we analyzed gene expression profiles of doxifluridine after two weeks repeated administration in cynomolgus monkey. Kegg pathway analysis suggested that cytoskeletal rearrangement and cell adhesion remodeling were commonly occurred in colon, jejunum, and liver. However, expression of genes encoding extracellular matrix was distinguished colon from others. In colon, COL6A2, COL18A1, ELN, and LAMA5 were over-expressed. In contrast, genes included in same category were down-regulated in jejunum and liver. Interestingly, MMP7 and TIMP1, the key enzymes responsible for ECM regulation, were overexpressed in colon. Several studies were reported that both gene reduced cell sensitivity to chemotherapy-induced apoptosis. Therefore, we suggest they have potential as target for modulation of 5-FU action. In addition, the expression of genes which have been previously known to involve in 5-FU pathway, were examined in three organs. Particularly, there were more remarkable changes in colon than in others. In colon, ECGF1, DYPD, TYMS, DHFR, FPGS, DUT, BCL2, BAX, and BAK1 except CAD were expressed in the direction that was good response to doxifluridine. These results may provide that colon is a prominent target of doxifluridine and transcriptional profiling is useful to find new targets affecting the response to the drug.