• 제목/요약/키워드: Branched structure

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Sol의 물리화학적 변수들이 $Pb(Mg, Zn)_{1/3}Nb_{2/3}O_3$ 박막의 우선 배향성에 미치는 효과 (Effects of Physico-chemical Factors of Sol on the Degree of Preferred Orientation in $Pb(Mg, Zn)_{1/3}Nb_{2/3}O_3$ Thin Films)

  • 조문규;장현명;김광수
    • 한국세라믹학회지
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    • 제32권3호
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    • pp.305-312
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    • 1995
  • Thin films of Pb(Mg, Zn)1/3Nb2/3O3 were fabricated by spin coating the Pb-Mg-Zn-Nb-O complex alkoxide sols on(111) Pt-coated MgO (100) planes. It was observed that the content of H2O and the rheological characteristics of sol greatly influenced the orientation of perovskite grains after thin-film formation. A strong preferential orientation of (100)-type planes of the perovskite grains was obtained for the sol aged for 15 days with the molar ratio of H2O to total metal alkoxides=2. As small angle X-ray scattering experiment in the Porod region was performed to correlate the observed preferential orientation with the network structure of precursors at various stage of aging. It was shown that the degree of branching of the Pb-Mg-Zn-Nb-O precursor chain had a direct effect on the preferred oreintation, and weakly branched precursor systems led to highly oriented grains after thin-film formation.

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Evolution of a dextransucrase gene for constitutive and hyper-production and for synthesis of new structure dextran

  • 강희경;김도만;장석상
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2003년도 생물공학의 동향(XII)
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    • pp.545-549
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    • 2003
  • After irradiation of a cloned dextransucrase gene (dsrB742) with ultrasoft X-ray, an E. coli transformant (pDSRB742CK) was first developed for the expression of an extracellular dextransucrase, having increased activity and the synthesis of a highly branched dextran. Seven nucleotides of the parent gene (dsrB742) were changed in the nucleotide sequences of dsrB742ck. Among them, four nucleotides were changed at the ORF of dsrB742, resulting in a 30 amino acids deletion in the N-terminal of DSRB742 dextransucrase. The activity of DSRB742CK dextransucrase in culture supernatant was approximately 2.6 times higher (0.035 IU/ml) than that of the DSRB742 clone. The pDSRB742CK clone produced DSRB742CK dextransucrase when grown both on a sucrose medium (inducibly) and on a glucose medium (constitutively). The DSRB742 clone did not produce dextran constitutively on a glucose medium. DSRB742CK dextran had 15.6% branching and 2.7-times higher resistance to dextranase hydrolysis compared to DSRB742 dextran. $^{13}C-NMR$ showed that DSRB742CK dextran contained ${\alpha}-(1{\rightarrow}3)$ branch linkages that were not present in DSRB742 dextran.

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Structural Characteristics of Immunostimulating Polysaccharides from Lentinus edodes

  • Lee, Hee-Hwan;Lee, Jong-Seok;Cho, Jae-Yeol;Kim, Young-Eon;Hong, Eock-Kee
    • Journal of Microbiology and Biotechnology
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    • 제19권5호
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    • pp.455-461
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    • 2009
  • There is a significant amount of experimental evidence suggesting that polysaccharides from mushrooms enhance the host immune system by activating various mechanisms in immune cells, including macrophages. In this study, polysaccharides from Lentinus edodes were found to stimulate the functional activation of macrophages to secrete inflammatory mediators and cytokines and increase the phagocytotic uptake. The chemical properties of the stimulatory polysaccharides, CPFN-G-I, CPBN-G, and CPBA-G, were determined based on their monosaccharide composition, which mainly consisted of glucose and mannose. According to FT-IR and GC/MS, the structure of CPFN-G-I, purified from the fruiting body of L. edodes, was found to consist of a $\beta$-1,6-branched-$\beta$-1,4-glucan, whereas CPBN-G and CPBA-G, purified from the liquid culture broth, were found to be composed of a heteromannan. The configuration of the p-linkage and triple helical conformation of each polysaccharide were confirmed using a Fungi-Fluor kit and Congo red, respectively.

신고리원자력발전소 주변 해역 조간대의 해조상 및 군집구조 (Marine Algal Flora and Community Structure of the Intertidal Zone around Shingori Nuclear Power Plant, Korea)

  • 한수진;장재길;황용훈;손민호;최한길
    • 한국수산과학회지
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    • 제50권3호
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    • pp.319-325
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    • 2017
  • Marine algal flora and community structures were examined seasonally at three sites around the Shingori Nuclear Power Plant, Korea from February to November 2016. A total of 76 species were identified, including 9 green, 14 brown and 53 red algae. The greatest number of species occurred at Daesongri (51 species) followed by Sinamri (43 species) and at the discharge area (38 species) during the study period. Of the 76 seaweeds, 59 annuals and 17 warm tolerant species were recorded. Annual average biomass in dry weight varied from $168.02g/m^2$ at the discharge area to $222.53g/m^2$ at Sinamri. The coarsely branched form was the dominant functional form of seaweeds at the three sites. Seaweed community structures at the discharge site were distinguishable by decreasing species richness, biomass, species diversity index, richness index, and evenness index. The ratio of warm tolerance species and the dominance index values were remarkably higher at the discharge than those at the other sites.

Light and Electron Microscopic Observations on Erythrolobus coxiae gen.et sp.nov. (Porphyridiophyceae, Rhodophyta) from Texas U.S.A.

  • Scott , Joseph L.;Baca, Bart;Ott, Franklyn D.;West, John A.
    • ALGAE
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    • 제21권4호
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    • pp.407-416
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    • 2006
  • Low molecular weight carbohydrates, phycobilin pigments and cell structure using light and transmission electron microscopy were used to describe a new genus of unicellular red algae, Erythrolobus coxiae (Porphyridiales, Porphyrideophyceae, Rhodophyta). The nucleus of Erythrolobus is located at the cell periphery and the pyrenoid, enclosed by a cytoplasmic starch sheath, is in the cell center. The pyrenoid matrix contains branched tubular thylakoids and four or more chloroplast lobes extend from the pyrenoid along the cell periphery. A peripheral encircling thylakoid is absent. The Golgi apparatus faces outward at the cell periphery and is always associated with a mitochondrion. Porphyridium and Flintiella, the other members of the Porphyrideophyceae, also lack a peripheral encircling thylakoid and have an ER-mitochondria-Golgi association. The low molecular weight carbohydrates digeneaside and floridoside are present, unlike both Porphyridium and Flintiella, which have only floridoside. The phycobilin pigments B-phycoerythrin, R-phycocyanin and allophycocyanin are present, similar to Porphyridium purpureum. The cells have a slow gliding motility without changing shape and do not require substrate contact. The ultrastructural features are unique to members of the Porphyrideophyceae and recent molecular analyses clearly establish the validity of this new red algal class and the genus Erythrolobus.

Aberrant Hypoplastic Lung Tissue 에서 발생한 Bronchogenic Cyst (Bronchogenic Cyst in Aberrant Hypoplastic Lung Tissue)

  • 김종원;조광현;김의윤
    • Journal of Chest Surgery
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    • 제8권1호
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    • pp.13-18
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    • 1975
  • Developmental pulmonary abnormalities are known as rare condition. diagnosis was made at autopsy in the early cases reported, however, as diagnostic aids such as X-ray, bronchography, bronchoscopy and exploratory thoracotomy have come into use, the condition is being discovered more often recently in living persons, and it appears to occur with sufficient frequency to merit consideration in the differential diagnosis of certain chest conditions. According to Schneider and Boyden there are three main types of this abnormality: [1] Agenesis, in which there is complete absence of one or both lungs; there is no trace of bronchial or vascular supply or of parenchymal tissue. [2] Aplasia, in which there is suppression of all but a rudimentary bronchus which ends in a blind pouch; there are no vessels or parenchyma. [3] Hypoplasia, in which the bronchus is fully formed but is reduced in size and ends in a _ flesh structure which usually lies within the mediastinum. Rudimentary pulmonary parenchyma may be present around the bronchial stump and often is the site of cystic malformation. We experienced one case of hypoplastic lung with cystic malformation which was originated from a small aberrant rudimentary bronchus, and the rudimentary bronchus was branched from the right side of tracheal end. The diagnosis was finally confirmed by the histopathological finding. Now, we report this case with a brief review of literatures.

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부산시 오륙도 주변 해역의 해조 군집 (Marine Algal Communities around Oryukdo, Busan, Korea)

  • 최정화;최창근
    • 한국수산과학회지
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    • 제47권6호
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    • pp.960-972
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    • 2014
  • Marine algal flora and community structure were seasonally investigated at Oryukdo, on the southeast coast of Korea, from March 2011 to February 2014. A Total of 66 seaweed species including 6 green, 7 brown and 53 red algae were identified and 23 species were found throughout the survey period. Seaweed biomass was maximal during summer in 2012 (2276.2 g wet weight $m^{-2}$) and minimal in winter in 2012 (9.1 g wet weight $m^{-2}$). The dominant species in term of biomass were Undaria pinnatifida, Dictyopteris prolifera, Dictyota dichotoma, Sargassum horneri, Rhodymenia intricata, Acrosorium polyneurum, and Polyneura japonica during the suvery period. The flora could be classified into six functional groups: coarsely branched form (30.3%), filamentous form (24.2%), thick leather form (19.7%), sheet form (15.2%), jointed calcareous form (7.6%), and crustose form (3.0%). The numbers of marine algal species in the Oryukdo area were markedly reduced when compared with previous studies at Dongbaekseom in 1971. These results suggest possible future changes in the algal vegetation, considering the physical and chemical pollution loadings in the coastal marine environment of this area.

솔-젤법에 의한 강유전성 PZT 박막의 제조;(II) 치밀화 및 결정화에 미치는 촉매의 영향 (Preparation of Ferroelectric PZT Thin Film by Sol-Gel Processing; (II) Effect of Catalysts on Densification and Crystallization)

  • 김병호;박성호;김병호
    • 한국세라믹학회지
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    • 제32권7호
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    • pp.783-792
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    • 1995
  • Sol-Gel derived ferroelectric PZT thin films were fabricated on ITO/Glass and Si/SiO2 substrates. In order to investigate the effect of catalysts on the densification and crystallization of PZT thin films, a nitric acid or ammonium hydroxide was added to the PZT stock solution at the state of partial hydrolysis reaction. The measured pH for a stable PZT sol was 5.2~9.3. In case of an acid-catalyzed PZT sol, a highly condensed particulate PZT sol was formed by accelerating the hydrolysis reaction. But weakly branched polymeric PZT sol was formed with a base-catalyzed condition. The difference in densification behavior was not found in the pH range of added catalyst, but the refractive index of PZT thin film was increased rapidly as the annealing temperature increased. The PZT thin film annealed at 54$0^{\circ}C$ for 10 min was fully densified and its refractive index was above 2.4. When the annealing temperature increased, the transition from the pyrochlore phase to perovskite appeared at 54$0^{\circ}C$. The base-catalyzed PZT thin film suppressed to form the pyrochlore phase and proceeded effectively to convert the perovskite phase. This was due to the formation of polymeric molecular structure by controlling the hydrolysis and condensation reaction through the additiion of the ammonium hydroxide.

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동해안 울산 주변의 해조 군집 (Marine Algal Community of Ulsan, on the Eastern Coast of Korea)

  • 최창근;노현수
    • 한국수산과학회지
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    • 제43권3호
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    • pp.246-253
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    • 2010
  • The marine algal flora and community structure were investigated at three sites in Ulsan on the southeast coast of Korea between August 2005 and July 2006. Ninety-one benthic algae species were identified, including 14 Chlorophyta, 21 Phaeophyta, and 56 Rhodophyta species. Of the 91 seaweeds, 19 species were found throughout the survey period. The wet weight biomass ranged from 310.8 to 2,960.4 g $m^{-2}$ during the study period. The maximum biomass was recorded at Sinri, and the minimum was recorded at Daesong. The R/P, C/P and (R+C)/P values reflecting flora characteristics were 2.67, 0.67, and 3.33, respectively. The flora investigated could be classified into six functional groups: coarsely branched (46.2%), thick leathery (22.0%), filamentous (16.5%), Sheet (7.7%), jointed calcareous (4.4%), and crustose (3.3%) forms. A cluster analysis produced two groups that differed meaningfully: one included the site Sinri-summer and the other included the sites Daesong and Jinha.

Spinning Apparatus for the Dragline Silk in the Funnel-web Spider Agelena limbata(Araneae: Agelenidae)

  • Park, Jong-Gu;Moon, Myung-Jin
    • Animal cells and systems
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    • 제12권2호
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    • pp.109-116
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    • 2008
  • Among the four kinds of silk glands in the funnel-web spider Agelena limbata, the ampullate gland for dragline silk production is the most predominate one in both sexes, and is composed of three functional parts-excretory duct, storage ampulla and convoluted tail regions. Two pairs of major ampullate glands send secretory ductules to the anterior spinnerets, and another two pairs of minor ampullate glands supply the middle spinnerets. There are no apparent differences between the major and minor ampullate glands not only the external spigots but also their internal silk glands. However, the microstructure is very unique in this spider, because each gland has spherical shaped storage sac with twig-like branched tails. Nevertheless, the wall of the secretory region is similarly composed of a single layer of epithelial cells. The mature secretory silks in glandular epithelium are closely packed and accumulated as electron-opaque vesicles. Most of the secretory products which originated from the rough endoplasmic reticula(rER) are grown up by fusion with the surrounding small vesicles however, the Golgi complex does not seem to play an important role in this process of secretion.