• Title/Summary/Keyword: biomaterials

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Inhibitory Effect of Camp Antagonist and Pka Inhibitors, and Stimulatory Effect of Adenylate Cyclase Agonist on Cathepsin K Processing in Cultured Mouse Osteoclasts (cAMP 길항제와 PKA 억제제 및 Adenylate Cyclase 촉진제의 백서 파골세포에서 Cathepsin K 생성에 대한 효과)

  • Shim, Youn-Soo
    • Journal of dental hygiene science
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    • v.6 no.1
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    • pp.1-9
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    • 2006
  • Cathepsin K (cat K) is the major cysteine protease expressed in osteoclasts and was thought to play a key role in matrix degradation during bone resorption. It was shown that the intracellular maturation of cat K was prevented by the cAMP antagonist, Rp-cAMP, and the protein kinase A (PKA) inhibitors of KT5720 and H89. In contrast, forskolin, a adenylate cyclase agonist, rather induced Cat K processing and maturation in osteoclasts. Furthermore, to determine whether cat K processing and maturation signaling involves protein kinase C (PKC), mouse total bone cells were treated with calphostin C, a specific inhibitor of PKC, however, no effect was observed, indicating that calphostin C did not affect to osteoclast-mediated cat K processing and maturation. Thus, it is indicated that the cAMP-PKA signaling pathway regulates cat K maturation in osteoclasts. Since secreted proenzymes have the potential to reenter the cell via M6P receptor, to prevent this possibility, it was tested cAMP antagonist Rp-cAMP and the PKA inhibitors KT5720 and H89 in the absence or presence of M6P. Inhibition of cat K processing by Rp-cAMP, KT5720, or H89 was observed in a dose-dependent manner. Furthermore, the addition of M6P resulted in enhanced potency of Rp-cAMP, KT5720 and H89. These dose-dependently inhibited in vitro bone resorption with a potency similar to that observed for inhibition of cat K processing.

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Tensile bond strength of chairside reline resin to denture bases fabricated by subtractive and additive manufacturing (적층가공과 절삭가공으로 제작한 의치상과 직접 첨상용 레진 간의 인장결합강도 비교)

  • Kim, Hyo-Seong;Jung, Ji-Hye;Bae, Ji-Myung;Kim, Jeong-Mi;Kim, Yu-Lee
    • The Journal of Korean Academy of Prosthodontics
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    • v.58 no.3
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    • pp.177-184
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    • 2020
  • Purpose: The purpose of this study was to compare and evaluate the tensile bond strength of chairside reline resin to denture base resin fabricated by different methods (subtractive manufacturing, additive manufacturing, and conventional heat-curing). Materials and methods: Denture base specimens were fabricated as cuboid specimens with a width of 25 mm × length 25 mm × height 3 mm by subtractive manufacturing (VITA VIONIC BASE), additive manufacturing (NextDent Base) and conventional heat-curing (Lucitone 199). After storing the specimens in distilled water at 37℃ for 30 days and drying them, they were relined with polyethyl methacrylate (PEMA) chairside reline resin (REBASE II Normal). The subtractive and additive manufacturing groups were set as the experimental group, and the heat-curing group was set as the control group. Ten specimens were prepared for each group. After storing all bound specimens in distilled water at 37℃ for 24 hours, the tensile bond strength between denture bases and chairside reline resin was measured by a universal testing machine at a crosshead speed of 10 mm/min. The fracture pattern of each specimen was analyzed and classified into adhesive failure, cohesive failure, and mixed failure. Tensile bond strength, according to the fabrication method, was analyzed by 1-way ANOVA and Bonferroni's method (α=.05). Results: Mean tensile bond strength of the heat-curing group (2.45 ± 0.39 MPa) and subtractive manufacturing group (2.33 ± 0.39 MPa) had no significant difference (P>.999). The additive manufacturing group showed significantly lower tensile bond strength (1.23 ± 0.36 MPa) compared to the other groups (P<.001). Most specimens of heat-curing and subtractive manufacturing groups had mixed failure, but mixed failure and adhesive failure showed the same frequency in additive manufacturing group. Conclusion: The mean tensile bond strength of the subtractive manufacturing group was not significantly different from the heat-curing group. The additive manufacturing group showed significantly lower mean tensile bond strength than the other two groups.

Chemical Constituents and Flavonoids in Citrus Pressed Cake (감귤착즙박의 화학성분과 플라보노이드)

  • Yang, Young-Taek;Kim, Mi-Sil;Hyun, Kwan-Hee;Kim, Yong-Chol;Koh, Jeong-Sam
    • Korean Journal of Food Preservation
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    • v.15 no.1
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    • pp.94-98
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    • 2008
  • To search functional biomaterials of citrus pressed cake, the chemical constituents were analyzed Moisture content of citrus pressed cake varied slightly with sampling time. Moisture, non-nitrogen compounds, crude protein, crude fat, and ash of citrus pressed cake were 82.23% 16.94% 1.27% 2.5%, 0.58% (all w/w) on average, respectively. The chemical composition of citrus pressed cake was more similar to the peel than to the flesh of Citrus unshiu var: miyakawa. The pH, acid content, and pectin content were 3.57, 0.43% (w/w) and 1.49% (w/w), respectively. The vitamin C content of peel of Citrus unshiu var. miyakawa was 87.1mg/100g, and was higher than the 46.4mg/100g of citrus pressed cake. Total carotenoids of citrus pressed cake, and the peel and flesh of Citrus unshiu var. miyakawa, were 512.2mg/kg, 2,649.5mg/kg, and 199.4mg/kg, respectively. Therefore, citrus pressed cake may be utilized as a natural source of pectin, flavonoids and carotenoids. The major inorganic elements of citrus pressed cake were 201.3mg/100g of K, 47.9mg/100g of Ca, 19.4/100g of P, and 17.8/100g of Mg. The major free sugar contents of citrus pressed cake were 3.05% (w/w) fructose, 2.91% (w/w) glucose, and 4.94%(w/w) sucrose. Total free sugar was 9.91% (w/w), corresponding to 58.5% of 1be non-nitrogen compounds. The main flavonoids of Citrus unshiuwere narirutin, hesperidin, and rutin. Neohesperidin and hesperetin were also detected in trace amounts. Themajor flavonoids of citrus pressed cake were hesperidin and narirutin, and the content of hesperidin was 194.6mg/100g.

Quality Characteristics of Sikhe Prepared with the Roots Powder of Doraji (Platycodon grandiflorum A. DE. Candolle) (도라지 분말을 첨가한 식혜의 품질 특성)

  • Jeong, Seung-Il;Yu, Hyeon Hee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.5
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    • pp.759-765
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    • 2013
  • In this study, we investigated the quality characteristics of Sikhye, a traditional Korean drink, made with various amounts (0.5, 1, 2, and 3%) of powder from the roots of Doraji (RPD), for different storage periods (1, 3, 5, 7, 10, 13, or 15 days). The pH and Hunter's L value of Sikhye decreased with higher amounts of added RPD, while saccharinity as well as "a" and b values increased. During storage, pH and Hunter's L value of Sikhye tended to decrease while "a" and b values increased. The saccharinity of Sikhye with 0.5% and 1% RPD reached its maximum values on the tenth storage day and continuously decreased during the storage period. In contrast, the saccharinity of Sikhye with 2% and 3% RPD increased during the storage period, and had its maximum saccharinity on the fifteenth storage day. During the storage of Sikhye the total microbial cell count, typically $3.19{\sim}0.35{\times}10^2$ CFU/mL on the third storage day, was undetected in Sikhye with 3% RPD. The total microbial cell count of Sikhye without RPD increased to $1.91{\times}10^9$ CFU/mL by the fifteenth storage day, while Sikhye with 0.5, 1, 2, and 3% RPD added contained $8.43{\times}10^8$, $9.77{\times}10^7$, $2.10{\times}10^7$, and $7.21{\times}10^6$ CFU/mL, respectively. Thus, the total cell count was lower with higher additions of RPD. In sensory tests, the Sikhye control, or with 0.5% and 1% RPD added, didn't show significant differences in the texture of rice granules, plumpness of rice granules, floating of rice granules, taste, flavor, and sweetness values. The overall preference was highest (5.38) for Sikhye with 0.5% RPD, followed by the control, 1% RPD, 2% RPD and 3% RPD. In conclusion, according to preference tests, we recommended the addition of 0.5% or 1% RPD in Sikhye.

Immune Enhancement of Polysaccharide from Submerged Culture with Phellinus linteus in the Medium Supplemented with Ginseng Extract (수삼추출물 첨가 혼합배지에서 조제된 상황 균사체 심부배양물 다당획분의 면역활성 증진)

  • Kim, Hoon;Song, Ki-Yun;Jeong, Jae-Hyun;Jeong, Heon-Sang;Lee, Hyeon-Yong;Yu, Kwang-Won
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.1
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    • pp.20-28
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    • 2011
  • Crude polysaccharide (CP) was fractionated from the submerged culture (containing both mycelia and culture broth, SC) with Phellinus linteus (PL) in mushroom complete medium (MCM) supplemented with ginseng extract ($65^{\circ}$Bx, GE) to enhance the immune activity. PL-GE-15-CP from SC cultivated in MCM supplemented with GE-15% (v/v, a ratio of MCM volume to GE) showed significantly higher macrophage stimulation (1.45 fold of the saline control at $100{\mu}g$/mL) than PL-GE-5 and 10-CP with GE-5 and 10%, or PL-CP from SC without GE. The potent intestinal immune system modulating activity through Peyer's patch was also obtained by PL-GE-15-CP (1.46 fold). When PL-GE-15-CP further fractionated on DEAE-Sepharose CL-6B (Cl- form), PL-GE-15-CP-II was the significantly higher than others from PL-GE-15-CP or PL-CP on macrophage stimulation, interleukin (IL)-12 production and intestinal immune system modulation (1.54, 3.96 and 1.56 fold, respectively). PL-GE-15-CP-II also had higher anti-metastatic activity against colon 26-M3.1 carcinoma cell (57.3% inhibition of tumor control, $200{\mu}g$/mouse) rather than PL-CP-II. This active fraction (PL-GE-15-CP-II) mainly contained neutral sugar (82.45%) and uronic acid (12.99%), and component sugar analysis showed that PL-GE-15-CP-II consisted mainly of uronic acid, Ara, Man, Gal and Glc (molar ratio of 0.52:0.97:0.63:1.00:0.54). Furthermore, the activity of GE culture was higher compared with culture without GE, indicating that GE helped to enhance the immune activity of P. linteus; also, it is assumed that the polysaccharide plays an important role in immune enhancement.

Effect of cavity shape, bond quality and volume on dentin bond strength (와동의 형태, 접착층의 성숙도, 및 와동의 부피가 상아질 접착력에 미치는 영향)

  • Lee, Hyo-Jin;Kim, Jong-Soon;Lee, Shin-Jae;Lim, Bum-Soon;Baek, Seung-Ho;Cho, Byeong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.30 no.6
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    • pp.450-460
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    • 2005
  • The aim of this study was to evaluate the effect of cavity shape, bond quality of bonding agent and volume of resin composite on shrinkage stress developed at the cavity floor. This was done by measuring the shear bond strength with respect to iris materials (cavity shape , adhesive-coated dentin as a high C-factor and Teflon-coated metal as a low C-factor), bonding agents (bond quality: $Scotchbond^{TM}$ Multi-purpose and Xeno III) and iris hole diameters (volume; 1mm or 3mm in $diameter{\times}1.5mm$ in thickness). Ninety-six molars were randomly divided into 8 groups ($2{\times}2{\times}2$ experimental setup). In order to simulate a Class I cavity, shear bond strength was measured on the flat occlusal dentin surface with irises. The iris hole was filled with Z250 restorative resin composite in a bulk-filling manner. The data was analyzed using three-way ANOVA and the Tukey test. Fracture mode analysis was also done When the cavity had high C-factor, good bond quality and large volume, the bond strength decreased significantly The volume of resin composite restricted within the well-bonded cavity walls is also be suggested to be included in the concept of C-factor, as well as the cavity shape and bond quality. Since the bond quality and volume can exaggerate the effect of cavity shape on the shrinkage stress developed at the resin-dentin bond, resin composites must be filled in a method, which minimizes the volume that can increase the C-factor.

Changes of Furfural and Levulinic Acid Yield from Small-diameter Quercus mongolica Depending on Dilute Acid Pretreatment Conditions (약산 전처리 조건에 따른 소경 신갈나무 유래 푸르푸랄 및 레불린산의 함량 변화)

  • Jang, Soo-Kyeong;Jeong, Han-Seob;Hong, Chang-Young;Kim, Ho-Yong;Ryu, Ga-Hee;Yeo, Hwanmyeong;Choi, Joon Won;Choi, In-Gyu
    • Journal of the Korean Wood Science and Technology
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    • v.43 no.6
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    • pp.838-850
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    • 2015
  • In this study, dilute acid pretreatment was operated using small-diameter Quercus mongolica for evaluating the yield change of furfural and levulinic acid depending on pretreatment factors. The dilute acid pretreatment was conducted depending on reaction temperature ($140-180^{\circ}C$), reaction time (10-30 min), and sulfuric acid concentration (0-2%, w/w). Then, glucose, XMG (xylose + mannose + galactose), furfural, and levulinic acid contents in the liquid hydrolyzate were measured and analyzed after pretreatment. Glucose content increased to 16.02% as reaction temperature, reaction time, and sulfuric acid concentration increased, but it decreased at the sulfuric acid concentration of 2% (reaction temperature: > $170^{\circ}C$, reaction time: > 20 min). On the other hand, reaction temperature had a strong influenced on XMG content, and XMG content decreased to 1.63% through increasing of reaction temperature and sulfuric acid concentration, but XMG content was less affected by changes of reaction time. Furfural content increased with the increase of reaction temperature, reaction time, and sulfuric acid concentration, and maximum furfural content was 7.61% (reaction temperature: $180^{\circ}C$, reaction time: 20 min, sulfuric acid concentration: 1%) based on a weight of raw material, while furfural content was dropped in more severe condition than in maximum furfural content condition. Levulinic acid content also increased with higher reaction temperature, reaction time, and sulfuric acid concentration. Especially, the sharp increase of levulinic acid content was observed above $170^{\circ}C$, and maximum levulinic acid content was 10.98% (reaction temperature: $180^{\circ}C$, reaction time: 30 min, sulfuric acid concentration: 2%). However, less than 1% of furfural and levulinic acid content was obtained in non-acidic catalyst condition that in whole conditions of reaction temperature and reaction time.

Enzymatic Hydrolysis of Rice Straw, a Lignocellulosic Biomass, by Extracellular Enzymes from Fomitopsis palustris (Fomitopsis palustris의 균체 외 효소에 의한 볏짚 당화에 관한 연구)

  • Kim, Yoon-Hee;Cho, Moon-Jung;Shin, Keum;Kim, Tae-Jong;Kim, Nam-Hun;Kim, Yeong-Suk
    • Journal of the Korean Wood Science and Technology
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    • v.38 no.3
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    • pp.262-273
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    • 2010
  • In the enzymatic hydrolysis of rice straw and wood meals using extra-cellular enzymes from Fomitopsis palustris, key factors which enhanced the sugar conversion yield were investigated in this work, such as enzyme production and enzyme reaction conditions, surfactant effects, and the surface structure of substrates. F. palustris cultured with softwood mixture produced 12.0 U/$m{\ell}$ for endo-${\beta}$-1,4-gulcanase (EG), 116.68 U/$m{\ell}$ for ${\beta}$-glucosidase (BGL), 18.82 U/$m{\ell}$ for cellobiohydrolase (CBH), and 13.33 U/$m{\ell}$ for ${\beta}$-xylosidase (BXL). These levels of BGL, CBH, and BXL activities were two to four folds more than enzyme activities of F. palustris cultured with rice straw. The optimum reaction conditions of cellulase-RS which produced by F. palustris with rice straw and cellulase-SW which produced by F. palustris with softwood mixture were pH 5.0 at $45^{\circ}C$ and pH 5.0 at $50^{\circ}C$, respectively. The sugar conversion yield of cellulase-SW had the highest value of $40.6{\pm}0.6%$ within 72 h when rice straw was used as substrate. By adding 0.1% Tween 20 (w/w-substrate), the sugar conversion yield of rice straw was increased to 44%, which was about four fifths sugar conversion yield of commercial enzyme, Celluclast 1.5L (Novozyme A/S). A low crystallinity and an intensive fibril surface observed by the scanning electron microscope may explain the high sugar conversion yield of rice straw.

Fabrication and Characterization of Transparent Conductive Film based on Bacterial Cellulose (Bacterial cellulose를 기반으로 하는 투명전도성막의 제조 및 특성평가)

  • Yim, Eun-Chae;Kim, Seong-Jun;Kee, Chang-Doo
    • Korean Chemical Engineering Research
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    • v.51 no.6
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    • pp.766-773
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    • 2013
  • A transparent film was fabricated based on bacterial cellulose (BC), BC has excellent physical strength and stability at high temperature and it is an environmental friendly flexible material. In order to improve the conductivity, silver nanowire (AgNW) and/or graphene were introduced to the BC membrane. The aspect ratio of the AgNW synthesized in this study was 214, with a length of $15{\mu}m$ and width of 70 nm. The higher aspect ratio improved the conductivity by reducing the contact resistance. The thermal and electrical properties of 7 types of films prepared were investigated. Each film was fabricated with rectangular shape ($2mm{\times}2mm{\times}50{\mu}m$). The films were scored with a net shape by a knife, and filled with AgNW and graphene to bestow conductivity. The film filled with AgNW showed favorable electrical characteristics with a thickness of $350{\mu}m$, electron concentration of $1.53{\times}10^{19}$, electron mobility of $6.63{\times}10^5$, and resistivity of 0.28. The film filled with graphene had a thickness of $360{\mu}m$, electron concentration of $7.74{\times}10^{17}$, electron mobility of 0.17, and resistivity of 4.78. The transmittances at 550 nm were 98.1% and 80.9%, respectively. All the films were able to light LEDs bulbs although their brightness differed. A thermal stability test of the BC and PET films at $150{\pm}5^{\circ}C$ showed that the BC film was more stable, whereas the PET film was quickly banded. From these results, it was confirmed that there it is possible to fabricate new transparent conductivity films based on BC.

The Effects of RGDS Tetrapeptide on the Calcification of the Bovine Pericardium Transplanted Subcutaneously in Rats (흰쥐에서 RGDS tetrapeptide가 소 심낭 이식절편의 피하이식 후 석회화에 미치는 영향)

  • Jin, Ung;Lee, Ju-Hyeon;Kim, Chi-Kyung;Lee, Sun-Hee
    • Journal of Chest Surgery
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    • v.35 no.2
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    • pp.94-101
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    • 2002
  • All kinds of tissue valves must be pretreated for the inactivation of immunologic properties and the strengthening of tissue before implantation. However, the tissue valves are gradually denatured with the calcification process and they eventually lose their functions. Recent reports have shown the existence of specific calcium binding non collagenous proteins in the calcified area of implanted biomaterials. This experiment was intended to confirm the effect of pretreatment with RGDS(Arg-Gly-Asp-Ser) tetrapeptide on the calcification of subcutaneously implanted bovine pericardium in rats. RGDS tetrapeptide has the same amino acid sequence of attachment site of specific calcium binding non collagenous proteins. Material and Method: All bovine pericardial pieces were fixed with 0.6% glutaraldehyde. The pretreatments were done using 5 different methods, groupI, with normal saline for 60 minutes, groupII, with 0.5% GRSD(Gly-Arg-Scr-Asp) tetrapeptide solution for 60 minutes, group III : with 0.5% RGDS(Arg-Gly-Asp-Ser) tctrapeptide for 30 minutes, group IV ; with 0.5% RGDS for 60 minutes, and group V : with 0.5% RGDS for 120 minutes. The pretreated bovine pericardial pieces were implanted subcutaneously at the abdominal sites of rats. 30 days after the implantation, the implanted bovine pericardial tissue were examined radiologically, biochemically, and histologically to measure the severity of calcification. Result: On the radiological examination, group I ; 68.42$\pm$3.06, group II , 64.25$\pm$5.58 showed significant difference with group III: 48.00$\pm$3.57, group IV; 43.67$\pm$2.31, and group V ; 2.58$\pm$2.47(p<0.05). There was no difference between group I and II(p=0.105). On the biochemical examination, the amount of calcium in group I was , 33.09$\pm$6.59 mg, in group II ; 28.12$\pm$5.50mg, in group III ; 25.42$\pm$7.67mg, in group Ⅵ ; 20.51$\pm$5.11mg, and in group V : 15.43$\pm$4.25mg.