• Title, Summary, Keyword: Morphology Control

Search Result 1,045, Processing Time 0.047 seconds

Magnesium Thin Films Possessing New Corrosion Resistance by RF Magnetron Sputtering Method

  • Lee, M.H.;Yun, Y.S.;Kim, K.J.;Moon, K.M.;Bae, I.Y.
    • Corrosion Science and Technology
    • /
    • v.3 no.4
    • /
    • pp.148-153
    • /
    • 2004
  • Magnesium thin flims were prepared on cold-rolled steel substrates by RF magnetron sputtering technique. The influence of argon gas pressure and substrate bias voltage on their crystal orientation and morphology of the coated films were investigated by scanning electron microscopy (SEM) and X-ray diffraction, respectively. And the effect of crystal orientation and morphology of magnesium films on corrosion behaviors was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. From the experimental results, all the sputtered magnesium films showed obviously good corrosion resistance to compare with 99.99% magnesium target of the sputter-evaporation metal. Finally it was shown that the Corrosion-resistance of magnesium films can be improved greatly by controlling the crystal orientation and morphology with effective use of the plasma sputtering technique.

Shape Control of Gold Nanocrystal: Synthesis of Faceted Gold Nanoparticles and Construction of Morphology Diagram

  • Ahn, Hyo-Yong;Lee, Hye-Eun;Nam, Ki Tae
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • /
    • pp.281.1-281.1
    • /
    • 2013
  • Shape control of gold nanocrystal is still one of the most important challenges remaining to achieve geometry dependent properties. Thus far, several strategies have been developed to control the shape of nanoparticles, such as adding capping agents and diverse additives or adjusting the temperature and pH. Here, we used an already established seed-mediated method that allowed us to focus on controlling the growth stage. Cetyltrimethylammonium bromide (CTAB) and ascorbic acid (AA) were used as the ligand and the reducing agent, respectively, without using any additional additives during the growth stage. We investigated how the relative ratio of CTAB and AA concentrations could be a major determinant of nanoparticle shape over a wide concentration range of CTAB and AA. As a result, a morphology diagram was constructed experimentally that covered the growth conditions of rods, cuboctahedra, cubes, and rhombic dodecahedra. The trends in the morphology diagram emphasize the importance of the interplay between CTAB and AA. Furthermore, high-index faceted gold nanocrystal was obtained by two step seeded growth. Already synthesized cubic particles developed into hexoctahedral nanocrystal consisting of 48 identical {321} facets, which indicates that the growth of gold nanocrystal is affected by initial morphology of seed particles. The hexoctahedral gold nanoparticles can be used in catalysis and optical applications which exploiting their unique geometry. Our research can provide useful guidelines for designing various facetted geometries.

  • PDF

Sea Tangle Supplementation Alters Intestinal Morphology in Streptozotocin-induced Diabetic Rats and Lowers Glucose Absorption

  • Lee, Kyeung-Soon;Seo, Jung-Sook;Choi, Young-Sun
    • Food Science and Biotechnology
    • /
    • v.16 no.6
    • /
    • pp.879-883
    • /
    • 2007
  • This study examined whether dietary supplementation with sea tangle alters the intestinal morphology of streptozotocin-induced diabetic rats and affects the glucose absorption rate. Forty male Sprague-Dawley rats were divided into 2 groups and fed either a control (AIN76-based) diet or a sea tangle-supplemented diet. After 3 weeks, 10 rats in each group received an intramuscular injection of streptozotocin (45 mg/kg BW), and feeding was continued for 3 additional weeks. Dietary supplementation with sea tangle resulted in a lower fasting plasma glucose level compared with the control diet in diabetic rats. Scanning electron micrographs revealed serious damage to the jejunal villi of diabetic rats fed the control diet, whereas supplementation with sea tangle alleviated the damage. In a separate experiment, 20 male Sprague-Dawley rats were divided into 2 groups and fed either a control diet or a sea tangle-supplemented diet for 5 weeks, and fasted rats were subjected to in situ single-pass perfusion. The glucose absorption rate determined in the absence of digesta was decreased by 34% in the jejunum of rats fed a sea tangle diet compared with those fed a control diet. In conclusion, sea tangle supplementation lowered glucose absorption rate, altered intestinal morphology, and appeared to protect villi from damage caused by diabetes mellitus.

Nanotube Morphology Control of Ti-30Nb-xTa Alloys by Applied Voltages

  • Kim, Eun-Sil;Choe, Han-Cheol
    • Proceedings of the Korean Institute of Surface Engineering Conference
    • /
    • /
    • pp.78-78
    • /
    • 2013
  • This study has investigated the nanotube morphology control of Ti-30Nb-xTa alloys by applied voltages. The morphology changed from small diameter to large diameter with increasing applied voltage, whereas, changed from large diameter to small diameter with decreasing applied voltage.

  • PDF

EFFECT OF DIFFERENT STERILIZATION METHODS ON THE SURFACE MORPHOLOGY OF PPDO-hybrid-PLGA NANOFIBER SCAFFOLD AND ATTACHMENTS OF PC12 CELL (다양한 소독방법이 PPDO-hybrid-PLGA nanofiber scaffold의 형태와 세포부착에 미치는 영향에 관한 연구)

  • Lee, Ju-Hyon;Min, Hyun-Gi;Jung, Ju-Young;Kang, Na-Ra
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
    • /
    • v.34 no.6
    • /
    • pp.635-639
    • /
    • 2008
  • Objectives : the effect of different sterilization methods on the surface morphology of PPDO-hybrid-PLGA nanofiber scaffold and attachments of PC12 cell were investigated. Methods : Poly (p-dioxone)-hybrid-Poly (lactide-glycolide) (PPDO-hybrid-PLGA) nanofiber scaffold, fabricated in a tube form with 1.5 mm internal diameter, 0.2 mm thickness and 5 mm length, was prepared using electrospinning method. To study the surface morphology using SEM, The study group and control group in respective were; Control:Non-sterilized scaffold, Group I:scaffold sterilized with 70% Alcohol, Group II: scaffold sterilized with Ethylene Oxide at $65^{\circ}C$, and Group III: scaffold sterilized with Ethylene Oxide at $37^{\circ}C$. To investigate viability of the PC12 cell on the scaffold, The study group and control group in respective were; Control: sterilized with 70% Alcohol, Group I: sterilized with Ethylene Oxide at $65^{\circ}C$, and Group II: sterilized with Ethylene Oxide at $37^{\circ}C$. Results : 1. The surface morphology was slightly changed in Group I, II and Group III, compared with control. 2. The attachment of PC12 cells in Group I, II was not higher than in control Discussion : The attachment of PC12 cell is not influenced by different sterilization methods.

Effects of Lactitol and Tributyrin on Growth Performance, Small Intestinal Morphology and Enzyme Activity in Weaned Pigs

  • Hou, Y.Q.;Liu, Y.L.;Hu, J.;Shen, W.H.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.19 no.10
    • /
    • pp.1470-1477
    • /
    • 2006
  • One hundred and sixty crossbred pigs ($6.62{\pm}0.36kg$) weaned at day $18{\pm}1$ were used to investigate the effects of lactitol and tributyrin on performance, small intestinal morphology and enzyme activity. The pigs were assigned to one of five dietary groups (4 pens/diet with 8 pigs/pen) and were fed the negative control diet or the negative control diet supplemented with 10 g/kg glutamine (as a positive control), or 3 g/kg lactitol (${\beta}$-D-galactopyranosyl-($1{\rightarrow}4$)-D-sorbitol), or 5 g/kg tributyrin (butanoic acid 1,2,3-propanetriyl ester), or 3 g/kg lactitol+5 g/kg tributyrin. Body weight and feed intake were measured weekly during the 4-week study. On day 7, four pigs per dietary treatment were sacrificed to examine small intestinal morphology and enzyme activity. The results showed that: (1) Compared with the negative control diet, the positive control diet improved weight gain and feed efficiency during weeks 1-2 and over the entire study (p<0.05), and also decreased duodenal and ileal crypt depth (p<0.05), but did not alter intestinal enzyme activity (p>0.05). Lactitol improved feed efficiency during weeks 3-4 and over the entire study (p<0.05), but did not improve weight gain and feed intake, intestinal morphology or enzyme activity (p>0.05). Tributyrin improved weight gain and reduced feed/gain during weeks 3-4 and over the entire study. Tributyrin significantly decreased crypt depth in the duodenum and ileum, and increased duodenal lactase and ileal maltase activity (p<0.05). Lactitol+tributyrin increased weight gain during weeks 3-4 and over the entire study, and improved feed efficiency during weeks 1-2 and 3-4 and over the entire study (p<0.05). Lactitol+tributyrin increased the jejunal villus height, and decreased the duodenal and ileal crypt depth (p<0.05). Lactitol+tributyrin also increased jejunal lactase and sucrase activity (p<0.05). (2) Compared with the positive control, tributyrin improved weight gain and reduced feed/gain during weeks 3-4 (p<0.05), decreased the ileal crypt depth, and improved the duodenal lactase and sucrase activity (p<0.05). Lactitol+ tributyrin improved weight gain during weeks 3-4, improved feed efficiency during weeks 3-4 and over the entire study, increased the ileal villus height, and increased jejunal lactase, sucrase and maltase activity (p<0.05). These results showed that tributyrin improved performance, intestinal morphology and enzyme activity, while the effect of lactitol was very limited. These results also showed that, compared with glutamine, tributyrin was more effective in improving intestinal morphology and enzyme activity, and tributyrin exerted a superior effect in improving performance as weaning progressed. These observations suggest that, as a chemical for repairing intestinal atrophy, glutamine and tributyrin should be used in the first and second periods of the starter phase, respectively.

Morphology control of inkjet-printed small-molecule organic thin-film transistors with bank structures

  • Kim, Yong-Hoon;Park, Sung-Kyu
    • Journal of Information Display
    • /
    • v.12 no.4
    • /
    • pp.199-203
    • /
    • 2011
  • Reported herein is the film morphology control of inkjet-printed 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) organic thin-film transistors for the improvement of their performance and of the device-to-device uniformity. The morphology of the inkjetted TIPS-pentacene films was significantly influenced by the bank geometry such as the bank shapes and confinement area for the channel region. A specific confinement size led to the formation of uniform TIPS-pentacene channel layers and better electrical properties, which suggests that the ink volume and the solid concentration of the organic-semiconductor solutions should be considered in designing the bank geometry.

Evaluation of the effects of a low dose of Asiasari radix on stem cell morphology and proliferation

  • Park, Jun-Beom;Lee, Ji-Eun;Jin, Seong-Ho;Ko, Youngkyung;Jeong, Su-Hyeon
    • The Journal of Korean Medicine
    • /
    • v.37 no.2
    • /
    • pp.85-92
    • /
    • 2016
  • Objectives: Asiasari radix (A. radix) is a traditional herb medicine that has been used as an analgesic, antitussive, or anti-allergic remedy. This study was performed to evaluate the effects of low concentration of the Asiasarum heterotropoides extract on the morphology and proliferation of the human mesenchymal stem cells derived from periodontal tissue. Methods: Stem cells derived from gingiva were grown in the presence of A. radix at final concentrations that ranged from 0.001 to $0.01{\mu}g/mL$. The morphology of the cells was viewed under an inverted microscope and the analysis of cell proliferation was performed by using Cell Counting Kit-8 (CCK-8) on days 1 and 3. Results: The control group showed fibroblast morphology. The shapes of the cells in 0.001 and $0.01{\mu}g/mL$ of A. radix were similar to that of the untreated control group. The cultures growing in the presence of A. radix at day 1 showed an increase in the CCK-8 value. The relative values of CCK-8 assays of 0.001 and $0.01{\mu}g/mL$ of A. radix are $130.6%{\pm}1.8%$ and $129.3%{\pm}1.5%$, respectively, when the CCK-8 result of the untreated control group at day 1 is considered 100% (P = 0.051). Conclusions: Within the limits of this study, low concentrations of A. radix seemed to increase the proliferation of the stem cells that were derived from the gingiva and did not have adverse effects on the morphology of the cells.

A STUDY ON THE CRANIOFACIAL MORPHOLOGY OF OPERATED CONGENITAL CLEFT LIP & PALATE (외과적 수술을 받은 선천성 구순 구개열자의 두개 안면 형태에 관한 연구)

  • To, Song-Hee;Sohn, Byung-Wha
    • The korean journal of orthodontics
    • /
    • v.23 no.4
    • /
    • pp.543-564
    • /
    • 1993
  • A cephalometric study was undertaken to reveal significant differences of craniofacial morphology of operated congenital cleft lip and palate subjects and control subjects. The material for this study consisted of 73 subjects with operated congenital cleft lip and palate subjects(53 males, 20 females) and 110 control subjects (7 males, 34 females) ranging from 3 to 14 years old. Each group was divided into four age groups (3-5, 6-8, 9-11, 12-14 year) and analyzed by Cohen's method and Burstone's method. The following conclusions were obtained ; 1. In Wit's appraisal, there was no difference the cleft lip and palate subjects and the control subjects. 2. In the cleft lip and palate subjects, they had smaller and more retrusive maxilla than the control subjects in both sexes. 3. In the cleft lip and palate subjects, they had more retrusive mandible than the control subjects in both sexes. 4. In the cleft lip and palate subjects, they had more concave profile than the control subjects.

  • PDF

Expression and Morphology of Crystal Proteins in Bacillus thuringiensis subsp. kurstaki Cry-B

  • Park, Hyeon-U;Kim, Ho-San;Kim, Yeong-Hun;Jin, Byeong-Rae;Gang, Seok-Gwon
    • Journal of Sericultural and Entomological Science
    • /
    • v.36 no.2
    • /
    • pp.157-161
    • /
    • 1994
  • To investigate the morphology of Bacillus thuringiensis crystal proteins, two type crystal protein genes, cryIA(c) gene under the control of cryIA(b) gene promoter and cryIIA gene under the control of its own promoter, were transformed in B. thuringiensis acrystalliferous mutant strain and the transformants were characterized by SDS-PAGE and scanning electron microscopy. The expression and formation of crystal proteins in B. thuringiensis subsp. kurstaki Cry-B revealed that crystal proteins appear to have same molecular weight and morphology to those of wild type strain's, suggesting that the expression and formation of crystal proteins affected not by host cell or recombination of cryIA(e) gene under the control of cryIA(b) gene promoter but by only structural fragment of protoxin.

  • PDF