Anionic Polymerization of Isocyanates with Optically Active Properties Shin, Yeong-Deuk; Ahn, Jun-Hwan; Lee, Jae-Suk
Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals,
10/1/2001, Letnik:
370, Številka:
1
Journal Article, Conference Proceeding
Random copolymers, an optically functionalized isocyanate containing disperse red 1 (DR1NCO) with a chiral isocyanate containing (s)-(-)-2-methylbutanol (MBI), were prepared by anionic polymerization ...in THF at -98°C with Na-Naph as a two-directional initiator. As the contents of MBI in the copolymer increased, the optical rotation of the polymer was also increased. To study about the optical activity change with initiator systems, homo polymer of MBI was synthesized with one-directional and two-directional initiator. The difference of optical activity in both systems was investigated using Circular Dichroism (CD) spectroscopy and optical rotation.
Typhoid fever is bacterial disease caused by Salmonella typhi. It is characterized by prolonged fever, abdominal pain, diarrhea, delirium, rose spot, and splenomgaly, and occasionally complicated ...with intestinal bleeding and perforation. We experienced a case of peculier type of typhoid fever associated with sphenoid sinusitis.
In Menetriers disease, the gastric mucasal hypertrophy is so great that the rugae looks like convolutions of the brain. Although this gross appearance is common to all cases of Menetriers disease, ...either the gastric glandular elements or the superficial epithelial elements may predominate; acid secretion may be high, normal, or low; and hypoproteinemia may or may not be present. There is no consensus about which of these features define the disease. The main abnormality is a remarkable hyperplasia of the mucous surface and foveolar cells, but its pathogenesis and pathophysiology are poorly understood. Menetrier's disease is rarely cited as a cause of hematemesis, although this complication is recognized and should be considered in any case of hematemesis in which rugal hypertrophy is found at gastrofiberscopy or upper gastrointestinal series (UGIS). Recently, we experienced a 37 year old man who presented with massive hematemesis and hypoproteinemia. Menetriers disease was suggested by laboratory findings, gastrofiberoscopy and UGIS. Massive UGI bleeding had repetitively occurred five times in spite of conservative management, so total gastrectomy was performed. The pathologic findings are consistent with those of Menetriess disease such as thickened hyperplastic mucosa of the gastric fundus with characteristic cystic dilatation of the deeper crypts. Thereafter, the patient have recovered in good general condition and UGI bleeding was stopped. We present a rare case of Menetries disease associated with masive UGI bleeding and a brief review of clinical and pathologic pictures and management.
익모초 물추출물이 흰쥐 대퇴동맥의 혈관경련에 미치는 영향 정용발; Yong Bal Jung; 김형환 ...
대한본초학회지(본초분과학회지),
06/2003, Letnik:
18, Številka:
2
Journal Article
Objective : In order to study the effect of water extract of Leonuri herba (ELS) on the subarachnoid hemorrhage animal model, the autologous whole blood was applied to the vicinity of the sprague ...dawley rat right femoral artery. Methods : Following periarterial application of autologous whole blood (PAB) and intraperitoneal injection of ELS (10, 100 and 300 mghg, P.o.), the vasomotor responses to ELS were identified and the histological changes, neovascularized blood vessel were observed. Results : Contractile response to ELS (10, 100 and 300 mg/kg, p.0.) was significantly decreased in the rat femoral arteries of PAB 5 and 7 days. In PAB 5 and 7 days, significantly increased vessel wall thickness and narrowed lumen were observed in comparison with the control group. In the arteries exposed to autologous whole blood for 5 and 7 days, a lot of newly generated capillaries in association with markedly curved blood vessel wall thickness, elastic lamina and irregularly oriented endothelial cells were observed in the periphery of the vessel wall. The number of neovascularized blood vessels were significantly decreased in the periphery of PAB with ELS (10, 100 and 300 mg/kg, p.0.) 5 and 7 days. In VEGF expression, Blood plus ELS (10, 100 and 300 mg/kg, p.0.)-exposed vessel were more weak expression than blood-exposed vessel to vein autologous whole blood for 5 and 7 days. Conclusions : From these results, we concluded that ELS inhibited posthemorrhagic chronic vasospasm and neovascularization in rat femoral artery model.
This paper describes a type of piezoelectric transformer with improved design principles. It consists of a thin rectangular piezoelectric ceramic plate having two input electrodes and one output ...electrode. The length of each input and output electrode is nearly one third of piezoelectric transformer itself. In the driving section, the ceramic plate is poled in the thickness direction reversely with each other, and has electrodes on both main faces. The electric input near its fundamental resonance frequency is applied to the driving section in parallel and the output voltage from the generating section is connected to the resistor load. Its equivalent circuit is derived from the Mason's model. The frequency characteristics near the resonance frequency under no load have been investigated. Moreover, using this piezoelectric transformer, we measured the LCD backlight characteristics.
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