• Tribology and Lubricants
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• v.23 no.1
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• pp.14-18
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• 2007

SCM415 alloy was implanted with nitrogen ions using plasma source ion implantation (PSII), at a dose range of $1{\times}10^{17}\;to\;6{\times}10^{17}N^{+}cm^{-2}$. Auger electron spectrometry (AES) was used to investigate the depth profile of the implanted layer. Friction and wear tests were carried out on a block-on-ring wear tester. Scanning electron microscopy (SEM) was used to observe the micro-morphology of the worn surface. The results revealed that after being implanted with nitrogen ions, the frictional coefficient of the surface layer decreased, and the wear resistance increased with the nitrogen dose. The tribological mechanism was mainly adhesive, and the adhesive wear tended to become weaker oxidative wear with the increase in the nitrogen dose. The effects were mainly attributed to the formation of a hard nitride precipitate and a supersaturated solid solution of nitrogen in the surface layer.

• Journal of the Korean Ceramic Society
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• v.34 no.5
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• pp.483-490
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• 1997

Al2O3/metal composites were fabricated by oxidation and reaction of molten Al-alloy into two types of commercial Al2O3-SiO2 fibrous insulation board. The growth rate, composition and microstructure of these materials were described. An AlZnMg(7075) alloy was selected as a parent alloy. Mixed polycrystalline fiber and glass phase fiber were used as a filler. The growth surface of an alloy was covered with and without SiO2. SiO2 powder was employed as a surface dopant to aid initial oxidation of Al-alloy. Al-alloy, SiO2, fiber block and growth inhibitor CaSiO3 were packed sequentially in a alumina crucible and oxidized in air at temperature range 90$0^{\circ}C$ to 120$0^{\circ}C$. The growth rate of composite layer was calculated by measuring the mass increasement(g) per unit surface($\textrm{cm}^2$). XRD and optical microscope were used to investigate the composition and phase of composites. The composite grown at 120$0^{\circ}C$ and with SiO2 dopant showed rapid growth rate. The growth behavior differed a little depending on the types of fiber used. The composites consist of $\alpha$-Al2O3, Al, Si and pore. The composite grown at 100$0^{\circ}C$ exhibited better microstructure compared to that grown at 120$0^{\circ}C$.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.5
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• pp.288-294
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• 2016

Chondrosarcoma is a malignant tumor that originates from cartilaginous cells and is characterized by cartilage formation. Only 5% to 10% of chondrosarcoma occurs in the head and neck area, and it is uncommon in the temporomandibular joint area. This report describes an unusual case with a rare, large chondrosarcoma in a 47-year-old woman who presented with painless swelling and trismus. Computed tomography showed a large mass approximately $8.5{\times}6.0$ cm in size arising adjacent to the lateral pterygoid plate and condyle. There were features suggestive of bone resorption. The tumor was resected in a single block with perilesional tissues, and a great auricular nerve graft was performed because of facial nerve sacrifice. Microscopic examination of sections stained with H&E revealed chondrocytes with irregular nuclei and heterogeneous hyper chromatic tumor cells embedded in the chondrocyte lacuna. The diagnosis was a grade I chondrosarcoma. There was no evidence of recurrence at the 8-month follow-up, and a reconstruction surgery with fibular osteocutaneous free flap was performed. We report this unusual entity and a review of the literature.

• BMB Reports
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• v.41 no.4
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• pp.278-286
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• 2008

Angiogenesis, the formation of blood vessels, is essential for preparing a closed circulatory system in the body, and for supplying oxygen and nutrition to tissues. Major diseases such as cancer, rheumatoid arthritis, and atherosclerosis include pathological angiogenesis in their malignant processes, suggesting anti-angiogenic therapy to be a new strategy for suppression of diseases. However, until the 1970s, the molecular basis of angiogenesis was largely unknown. In recent decades, extensive studies have revealed a variety of angiogenic factors and their receptors, including vascular endothelial growth factor (VEGF)-VEGFRs, Angiopoietin-Tie, Ephrin-EphRs and Delta-Notch to be the major regulators of angiogenesis in vertebrates. VEGF and its receptors play a central role in physiological as well as pathological angiogenesis, and functional inhibitors of VEGF and VEGFRs such as anti-VEGF neutralizing antibody and small molecules that block the tyrosine kinase activity of VEGFRs have recently been approved for use to treat patients with colorectal, lung, renal and liver cancers. These drugs have opened a novel field of cancer therapy, i.e. anti-angiogenesis therapy. However, as yet they cannot completely cure patients, and cancer cells could become resistant to these drugs. Thus, it is important to understand further the molecular mechanisms underlying not only VEGF-VEGFR signaling but also the VEGF-independent regulation of angiogenesis, and to learn how to improve anti-angiogenesis therapy.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.27.1-27.7
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• 2015

The aim of this study was to evaluate the clinical relevance of autogenous fresh demineralized tooth (Auto-FDT) prepared at chairside immediately after extraction for socket preservation. Teeth were processed to graft materials in block, chip, or powder types immediately after extraction. Extraction sockets were filled with these materials and dental implants were installed immediately or after a delay. A panoramic radiograph and a conebeam CT were taken. In two cases, tissue samples were taken for histologic examination. Vertical and horizontal maintenance of alveolar sockets showed some variance depending on the Auto-FDT and barrier membrane types used. Radiographs showed good bony healing. Histologic sections showed that it guided good new bone formation and resorption pattern of the Auto-FDT. This case series shows that Auto-FDT prepared at chairside could be a good material for the preservation of extraction sockets. This study will suggest the possibility of recycling autogenous tooth after immediate extraction.

• Rapid Communication in Photoscience
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• v.4 no.3
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• pp.70-72
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• 2015

Oligomers of p-phenylene vinylene and its derivatives have drawn much attention due to their unusual emission characteristics of showing increased emission when they form into nanoparticles. We have investigated the optical properties of the oligo-(p-phenylene vinylene) and its cyano-substituted derivatives in solution and in nanoaggregate media by femtosecond and picosecond time resolved fluorescence as well as stationary spectroscopies. All the spectroscopic data are consistent with the conclusion that the cyano substitution on the ${\beta}$-position of oligo-(p-phenylene vinylene) leads to breakage of the otherwise planar structure of cyano-unsubstituted molecules, which opens up an extremely efficient, as fast as 100 fs, non-radiative relaxation channel of the excited state. Formation of the nanoaggregates reverts the effect to make the molecules planar and to block the non-radiative relaxation channel. Therefore, concerning the applications in organic electroluminescent devices and organic light emitting diodes, substitution by the cyano group is not advantageous, although such modification should be useful in respect of controlling fluorescence intensity in different media.

• Korean Journal of Pharmacognosy
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• v.33 no.1 s.128
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• pp.13-17
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• 2002

Helicobacter pylori infection is associated with type B gastritis, peptic ulcer, and gastric cancer. The vacuolation of cells induced by H. pylori is thought to be essential for the initiation and maintenance of gastric infection. The roles of H. pylori cytotoxin, urease, and ammonia in the vacuolation of HeLa cells were determined. Ammonium chloride augmented the neutral red uptake induced by H. pylori toxin. Acetohydroxamic acid (AHA) failed to block the neutral red uptake induced by H. pylori toxin. Leweifang significantly prevented the vacuolation of HeLa cells induced by H. pylori toxin or H. pylori toxin and ammonium chloride. Further investigation is required to determine the mechanisms of Leweifang for the inhibition of vacuole formation of eukaryotic cells in response to the H. pylori toxin.

• Journal of Fashion Business
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• v.8 no.5
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• pp.75-84
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• 2004

Fashion Illustration has become a key method in expressing Fashion, and is being applied in various fields of the modern world, where changes are so rapid that prescribing trends are meaningless. Fashion Illustration was stimulated through progress of wood block printing and development of printing techniques, and grew with fashion magazines. Fashion Illustration advanced along with the appearance of newspapers and magazines that were emerged due to historical demands such as development of printing techniques, spacial spread of human life, obliteration of traditional societies, diffusion of education systems, progress in postal systems, and appearance of commercial broadcast. Fashion Illustration showed growth and decline along with the influence of mass media such as magazines and photography, and the general publics demand. In this study, the author reviews Le Nouvau Mercure Galant, the magazine that first dealt with Fashion Illustrations. The author analyses the magazine in six stages of formation, growth, revolution, golden-age, decline, and reconstruction, to develope a theoretical analysis of Fashion Illustration and to give direction of use of Fashion Illustration in the future.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.76-83
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• 2006

Each tire has a critical speed at which a standing wave phenomenon occurs along the circumferential direction. If the standing waves are formed, the tire temperature is rapidly increased and it leads to tire failure eventually. As the formation of the standing waves is closely related to the tire stiffness, the effect of the tread pattern needs to be studied numerically. The standing wave phenomenon of a tire model with tread pattern is predicted by an explicit finite element method. The critical speed of the tire with tread pattern is in a good agreement with the experiment and is $15{\sim}20\;km/h$ lower than that of the tire without tread pattern. The effects of the inflation pressure and the vertical load on the critical speed are also investigated by using the tire model with tread pattern.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.4
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• pp.47-50
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• 2006

SCM415 alloy was implanted with nitrogen ions using plasma source ion implantation (PSII), at a dose range of $1{\times}10^{17}\;to\;6{\times}10^{17}\;N^+cm^{-2}$ Auger electron spectrometry (AES) was used to investigate the depth profile of the implanted layer. Friction and wear tests were carried out on a block-on-ring wear tester. Scanning electron microscopy (SEM) was used to observe the micro-morphology of the worn surface. The results revealed that after being implanted with nitrogen ions, the frictional coefficient of the surface layer decreased, and the wear resistance increased with the nitrogen dose. The tribological mechanism was mainly adhesive, and the adhesive wear tended to become weaker oxidative wear with the increase in the nitrogen dose. The effects were mainly attributed to the formation of a hard nitride precipitate and a supersaturated solid solution of nitrogen in the surface layer.