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Effects of Thermal and Mechanical Fatigue Stress on Bond Strength in Bracket Base Configurations (열적, 기계적 피로응력이 교정용 브라켓의 결합강도에 미치는 영향)

  • Kim, Jong-Ghee;Kim, Sang-Cheol
    • The korean journal of orthodontics
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    • v.30 no.5 s.82
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    • pp.625-642
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    • 2000
  • The purpose of this study is to evaluate the effects of mechanical and thermal fatigue stress on the shear, tensile and shear-tensile combined bond strengths(SBS, TBS, CBS) in various orthodontic brackets bonded to human premolars with chemically cured adhesive(Ortho-one, Bisco, USA). Five types of commercially available metal brackets with various bracket base configurations of Photoetched base(Tomy, Japan), Non-Etched Foil Mesh base(Dentaurum, Germany), Micro-Etched Foil Mesh base(Ortho Organizers, USA), Chessboard base(Daesung, Korea), and Integral base(3M Unitek, USA) were used. Samples were divided into 3 groups, the first group was acted with shear-tensile combined loads($45^{\circ}$) of 200g for 4 weeks(mechanical fatigue stress), the second group was subjected to the 5,000 thermocycles of 15 second dwell time each in $5^{\circ}C\;and\;55^{\circ}C$ baths(thermal fatigue stress), and the third group was the control. Bond strengths were measured at the crosshead speed of 0.5mm/min. The cross-section of bracket base/adhesive interface and the fracture surface were examined with the stereoscope and the scanning electron microscope. The resin remnant on bracket base surface was assessed by ART(Adhesive Remnant Index). The obtained results were summarized as follows, 1. In static bond strength, Photoetched base bracket showed the maximum bond strength and Integral base bracket showed the minimum bond strength(p<0.05). In all brackets, shear bond strength(SBS) was in the greatest value and shear-tensile combined strength(CBS) was in the least value(p<0.05). 2. After mechanical fatigue test, Photoetched base bracket showed the maximum bond strength and Integral base bracket showed the minimum bond strength(p<0.05). In Photoetched base bracket and Micro-Etched Foil Mesh base bracket, shear bond strength(SBS), tensile bond strength(TBS) and shear-tensile combined strength(CBS) were decreased after mechanical fatigue test(p

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Environmental Characteristics of Seawater and Sediment in Mariculture Management Area in Ongjin-gun, Korea (옹진군 어장관리해역의 수질 및 퇴적물 환경 특성)

  • Kim, Sun-Young;Kim, Hyung-Chul;Lee, Won-Chan;Hwang, Dong-Woon;Hong, Sok-Jin;Kim, Jeong-Bae;Cho, Yoon-Sik;Kim, Chung-Sook
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.19 no.6
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    • pp.570-581
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    • 2013
  • To improve productivity of aquaculture animals with management of culturing grounds, survey of mariculture management area in Ongjin-gun about water quality and sedimentary environment had been conducted on June, August and November in 2011. Water temperature in surface and bottom waters ranged from 9.49 to $24.14^{\circ}C$. Salinity and dissolved oxygen concentrations were in the range of 23.19~31.49 and 5.48~9.36 mg/L, respectively, depending on the variation of water temperature. The average concentration of COD was 1.57 mg/L and the concentrations of DIN and DIP showed entirely low level. As the result of grain size analysis, sand(56.66 %) and silt(34.60 %) were predominated. The Mz of sediment showed a variation of 2.59 to $6.62{\O}$ and sorting appeared to be poorly sorted. The concentrations of COD and IL in surface sediment ranged from 1.00 to $11.03mg/g{\cdot}dry$ and 0.72 to 5.29 %, respectively, which showed relatively good positive correlations. On the environmental assessment of trace metals in surface sediment, geoaccumulation index ($I_{geo}$) class indicated that sediments were not contaminated by most of metallic elements except Cr and As. Our result implies that this study area showed good water quality and sediments were not polluted by organic matters and metallic elements.

THE ANTICANCER EFFECT OF PACLITAXEL($Taxol^{(R)}$) IN ORAL SQUAMOUS CELL CARCINOMA XENOGRAFT (이종 이식된 구강편평세포 암종에서 Paclitaxel ($Taxol^{(R)}$)의 항암 효과)

  • Kim, Ki-Hwan;Kim, Chul-Hwan;Han, Se-Jin;Lee, Jae-Hoon
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.28 no.2
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    • pp.95-110
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    • 2006
  • The treatment for oral and maxillofacial carcinoma with chemotherapeutic agents is evaluated by many effective methods to reduce the tumor mass and cancer cell proliferation. However these chemotherapy have many serious side effects, such as bone marrow suppression, renal toxicity, G-I troubles. Therefore a possible approach to develop a clinically applicable chemotherapeutic agent is to screen anticancer activity of Taxol which is known to have very little side effect and have been used to breast cancer and ovarian carcinoma. Taxol is a new anti-microtubular anti-cancer agent extracted from the bark of the Pacific yew, Taxus brevifolia. Paclitaxel(Taxol) acts by promoting tubulin polymerization and over stabilizing microtubules agianst depolymerization. Despite the constant improvements of methods of the cancer treatment especially chemotherapy, the rate of cancer metastasis and recurrent are not decreased. Thus the investigation of new drug which have very little side effect and a possible clinically application continues to be a high priority. Considering that the Taxol have shown very effective chemotherapeutic agent with relatively low toxicity in many solid tumors, it deserves to evaluate its efficacy in oral squamous cell carcinoma. In this study, to investigate the in-vivo and in-vitro anti-cancer efficacy of Taxol in oral squamous cell carcinoma and lastly, the potency of Paclitaxel in the clinical application for oral cancer was evaluated. In vivo study, after HN22 cell line were xenografted in nude mice, the growth of tumor mass was observed, 3 mg/Kg taxol was injected intraperitoneally into nude mice containing tumor mass. The methods of these study were measurement of total volume of tumor mass, histopathologic study, immunohistochemical study, drug resistance assay, growth curve, MTT assay, flow cytometry, cDNA microarray in vivo and in vitro. The results were obtained as following. 1. The visual inspection of the experimental group showed that the volume of the tumor mass was slightly decreased but no significant difference with control group. 2. Ki-67 index was decreased at weeks 4 in experimental group. 3. Microscopic view of the xenografted tumor mass showed well differentiated squamous cell carcinoma and after Taxol injection, some necrotic tissue was seen weeks 4. 4. The growth curve of the tumor cells were decreased after 1day Taxol treatment. 5. According to the MTT assay, HN22 cell line showed relative drug resistancy above $5\;{\mu}g/ml$ concentrations of Taxol. 6. In drug resistance assay, the decrease of cell counts was seen relatively according to concentration. 7. In Flow cytometry, G2M phase cell arrests were seen in low concentration of the Taxol, while S phase cell arrests were seen in high concentration of the Taxol. 8. Using cDNA microarray technique, variable gene expression of ANGPTL4, TXNRD1, FAS, RRAGA, CTGF, CYCLINEA, P19, DUSP5, CEBPG, BTG1 were detacted in the oral squamous cell carcinoma cell after taxol treatment. In this study paclitaxel is effective against oral squamous cell carcinoma cell lines in vitro, but week effect was observed in vivo. So we need continuous study about anticancer effect of taxol in vivo in oral squamous cell carcinoma.

Hatching Rate of Eggs, and Growth of Larvae and Juveniles from Selected Olive Flounder, Paralichthys olivaceus (선발 육종된 넙치, Paralichthys olivaceus의 부화율 및 자치어 성장)

  • Min, Byung-Hwa;Lee, Jeong-Ho;Noh, Jae-Koo;Kim, Hyun-Chul;Park, Choul-Ji;Choi, Sang-Jun;Myeong, Jeong-In
    • Development and Reproduction
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    • v.13 no.4
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    • pp.239-247
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    • 2009
  • Hatching rate, larval deformation and growth rate of selected olive flounder (Paralichthys olivaceus) for rapid growth were compared to those of the unselected fish. Fish were spawned on the same day and cultured under the similar conditions. The selected fish had a significantly higher eggs hatching rate, and lower larval deformation. The selected fish grew significantly faster, and at the end of the experiment (8 weeks after hatching) averaged 50.49${\pm}$2.67 mm in total length, 16.30${\pm}$0.08 mm in body height, and 1.036${\pm}$0.118 g in weight, compared to 40.55${\pm}$3.13 mm, 13.50${\pm}$0.96 mm, and 0.557${\pm}$0.073 g for unselected fish, respectively. The selected fish had a significantly higher body shape index, however lower condition factor than the unselected fish. The results of the present study demonstrate that the selected fish of the olive flounder for rapid growth had superior growth and improved body shape.

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Length-Weight Relations and Condition Factor (K) of Zacco platypus Along Trophic Gradients in Reservoir Ecosystems (인공호의 부영양화에 따른 피라미(Zacco platypus) 개체군의 전장-체중 관계 및 비만도 지수)

  • Ko, Dae-Geun;Han, Jeong-Ho;An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.45 no.2
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    • pp.174-189
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    • 2012
  • The objective of this study was to determine the weight-length relations and condition factor (K) of Zacco platypus, along the trophic gradients from oligotrophic to eutrophic state in six reservoir ecosystems ($B_aR$, $Y_yR$, $J_yR$, $G_pR$, $Y_dR$, and $M_sR$), during 2008~2010. The species was selected as a sentinel species for the study, due to its wide distribution and wide trophic gradient. The analysis of trophic state index (TSI), based on total phosphorus (TP) and chlorophyll-a (Chl-a), indicated that reservoirs of $Y_yR$ and $B_aR$ were classified as to be in an oligotrophic state (30~40), the $J_yR$ and $G_pR$ as mesotrophic (40~50), and the $Y_dR$ and $M_sR$ as eutrophic state (50~70). Total 47 species and 26,226 individuals were sampled from 6 reservoirs and sensitive species dominated in the oligotrophic reservoirs ($Y_yR$ and $B_aR$). In the mean time, the tolerant speciesdominated the community in the mesotrophic ($J_yR$ and $G_pR$) and eutrophic ($Y_dR$ and $M_sR$) reservoirs. Regression analysis of body weight, against the total length, indicated that the regression coefficient (b value) was lower in the oligotrophic reservoir (2.77~2.79) than the mesotrophic (3.07~3.17) and eutrophic reservoirs (3.15~ 3.21). This result suggests that the population growth rate Zacco platypus reflected the trophic gradients of the reservoirs. The analysis of condition factor (K) against the total length showed positive slopes (b>3.0) in mesotrophic and eutrophic reservoirs, and a negative slope (b<3.0) in oligotrophic reservoir. The variation of the regression slope of "b" in Z. platypus was accounted for 79.7% [$b=0.012{\times}TSI(TP)+2.395$, p=0.017] by the variation of TSI (TP) and 82.2% [$b=0.013{\times}TSI(Chl-a)+2.36$, p=0.013] by the variation of TSI (Chl-a). The proportion of DELT abnormality increased as the trophic state increases in the reservoirs. The overall data suggest that the growth of the fish populations, based on the length-weight relations and condition factor, reflected the trophic state of nutrient and phytoplankton biomass of the reservoir waters. Thus, in spite of the tolerant characteristics of Z. platypus, hypertrophic states might negatively affect the health of the population.

Bioavailability and Digestibility of Organic Calcium Sources by Bone Health Index (뼈건강 지표를 이용한 유기태 칼슘 급원의 생체이용성 및 소화율)

  • Han, Jeong-Ho;Kim, Eun-Mi;Cheong, Man-Ki;Chee, Sung-Kew;Chee, Kew-Mahn
    • Journal of Nutrition and Health
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    • v.43 no.1
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    • pp.12-25
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    • 2010
  • This study was carried out to evaluate the bioavailabilities and the digestibilities of oligopeptide chelated (peptide-Ca), anchovy bone (anchovy-Ca) and methionine hydroxyl analogue (MHA-Ca) calcium compared to those of calcium carbonate in rats. In exp1, $CaCO_3$, were added to the basal diet at level of 0, 30 and 60% calcium of the AIN-93G diet. In test groups, peptide-Ca, anchovy-Ca and MHA-Ca, were added to the basal diet to provide calcium at the level of 40% of AIN-93G. In exp1, the bioavailabilities were evaluated from the regression equation of the ratios of theological/ actual calcium intakes of each dietary treatment. In exp2, urine and feces was to evaluate the true- and apparent digestibility and apparent retention. In exp1, Ca-60% group had higher bone mineral density (BMD), bone mineral content (BMC) and bone breaking strength (BBS) than those of the other standard groups. The bone weight and ash content of the peptide-Ca and anchovy-Ca groups were significantly higher than those of the MHA-Ca. Bone calcium content were not significantly different from the test group. The bioavailability of the MHA-Ca group was shown higher BMD (71%), BS (38%) and BBS (27%) compared to another control group. But the regression coefficient for BMD, BS and BBS were lower compare with that of bone ash and BMC. In exp2, the true- and apparent digestibility of test groups were shown to over 90%. Peptide-Ca was not significantly different from other test group, but digestibility and retention were higher compare to other test groups. In conclusion, peptide-Ca, anchovy-Ca and MHA-Ca improved Ca bioavailability in the rats. The compounds were higher Ca digestibility compared with those of $CaCO_3$. It is assumed that difference of digestibility for test groups may be correlated to the bioavailability of test groups in BMD, BMC, BS, BBS and bone ash respectively.

LONG TERM GINSENG EFFECTS ON HYPERLIPIDEMIA IN MAN WITH FURTHER STUDY OF ITS ACTIONS ON ATHEROGENESIS AND FATTY LIVER IN RATS (사람의 과지혈증과 동맥경화 및 흰쥐 지방간에 미치는 인삼의 장기복용 효과 연구)

  • Yamamoto Masahiro;Kumagai Akira
    • Proceedings of the Ginseng society Conference
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    • 1984.09a
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    • pp.13-19
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    • 1984
  • In the previous symposium, authors reported about anti-atherogenic action of Panax ginseng, saying that red-ginseng powder increased serum HDL-cholesterol, decreased total cholesterol, TG, NEFA, in addition, decreased platelet adhesiveness. Later, Toyama group including me. reported that ginsenosides esp. $Rb_2$ enhanced HDL and decreased LDL. Also Matsuyama group and Kinki Univ. group reported that ginsenosides $Rg_1,\;Rb_2,$ etc. inhibited platelet aggregation. This paper will be divided into two parts: Experimental and clinical Experimental study; Using a highcholesterol-cholic acid-fed rats, effects of red ginseng extract and several ginsenosides on serum apoprotein-lipoproteins in relation to prostaglandins. Rats received $2\%$ cholesterol 1-1$\%$ cholic acid diet, ginseng extract or ginsenosides 2.5mg/100g/day for 9 days. Red ginseng extract, ginsenosides $Rb_2,\;Rc,\;Rb_1,\;and\;Rg_1,\;esp.\;Rb_2,$ increased HDL, apo-AI, Aii and $PGI_2,$ while they decreased LDL, apo-B and $TXA_2$. Clinical study: Effect of red ginseng powder on hyperlipidemia was observed. Long term administration of red ginseng powder manufactured by Office of Monopoly, Republic of Korea and offered by Japan-Korea Korean Ginseng Co., Kobe, at the dose of 2.7 g/day, was performed in patients with hyperlipidemia up to 4 years. The significant increase in serum HDL-cholesterol and also the significant decrease in total cholesterol, atherogenic index, TG, NEFA and lipoperoxide was observed with 3-48 month administration of red ginseng. Conclusions: Red ginseng and ginsenosides improved hyperlipidemia in rats and in man, with the improvement of blood apoproteins, lipoproteins and prostaglandins in experimental hyperlipidemic animals.

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SCIATIC NERVE REGENERATION USING CALCIUM PHOSPHATE COATED CONDUIT AND BRAIN-DERIVED NEUROTROPHIC FACTOR GENE-TRANSFECTED SCHWANN CELL IN RAT (인회석 박막 피복 도관과 Brain-derived neurotrophic factor(BDNF) 유전자 이입 슈반세포를 이용한 백서 좌골신경 재생에 관한 연구)

  • Choi, Won-Jae;Ahn, Kang-Min;Hwang, Soon-Jeong;Choung, Pill-Hoon;Kim, Myung-Jin;Kim, Nam-Yeol;Yoo, Sang-Bae;Jahng, Jeong-Won;Kim, Hyun-Man;Kim, Joong-Soo;Kim, Yun-Hee;Kim, Soung-Min;Lee, Jong-Ho
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.31 no.3
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    • pp.199-218
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    • 2005
  • Purpose of Study: Peripheral nerve regeneration depends on neurotrophism of distal nerve stump, recovery potential of neuron, supporting cell like Schwann cell and neurotrophic factors such as BDNF. Peripheral nerve regeneration can be enhanced by the conduit which connects the both sides of transected nerve. The conduit maintains the effects of neurotrophism and BDNF produced by Schwann cells which can be made by gene therapy. In this study, we tried to enhance the peripheral nerve regeneration by using calcium phosphate coated porous conduit and BDNF-Adenovirus infected Schwann cells in sciatic nerve of rats. Materials and Methods: Microporous filter which permits the tissue fluid essential for nerve regeneration and does not permit infiltration of fibroblasts, was made into 2mm diameter and 17mm length conduit. Then it was coated with calcium phosphate to improve the Schwann cell adhesion and survival. The coated filter was evaluated by SEM examination and MTT assay. For effective allogenic Schwann cell culture, dorsal root ganglia of 1-day old rat were extracted and treated with enzyme and antimitotic Ara-C. Human BDNF cDNA was obtained from cDNA library and amplified using PCR. BDNF gene was inserted into adenovirus shuttle vector pAACCMVpARS in which E1 was deleted. We infected the BDNF-Ad into 293 human mammary kidney cell-line and obtained the virus plaque 2 days later. RT-PCR was performed to evaluate the secretion of BDNF in infected Schwann cells. To determine the most optimal m.o.i of BDNF-Ad, we infected the Schwann cells with LacZ adenovirus in 1, 20, 50, 75, 100, 250 m.o.i for 2 hours and stained with ${\beta}$-galactosidase. Rats(n=24) weighing around 300g were used. Total 14mm sciatic nerve defect was made and connected with calcium phosphate coated conduits. Schwann cells$(1{\times}10^6)$ or BDNF-Ad infected Schwann cells$(1{\times}10^6)$ were injected in conduit and only media(MEM) was injected in control group. Twelve weeks after surgery, degree of nerve regeneration was evaluated with gait analysis, electrophysiologic measurements and histomorphometric analysis. Results: 1. Microporous Millipore filter was effective conduit which permitted the adhesion of Schwann cells and inhibited the adhesion of fibroblast. We could enhance the Schwann cell adhesion and survival by coating Millipore filter with calcium phosphate. 2. Schwann cell culture technique using repeated treatment of Ara-C and GDNF was established. The mean number of Schwann cells obtained 1 and 2 weeks after the culture were $1.54{\pm}4.0{\times}10^6$ and $9.66{\pm}9.6{\times}10^6$. 3. The mRNA of BDNF in BDNF-Ad infected Schwann cells was detected using RT-PCR. In Schwann cell $0.69\;{\mu}g/{\mu}l$ of DNA was detected and in BDNF-Adenovirus transfected Schwann cell $0.795\;{\mu}g/{\mu}l$ of DNA was detected. The most effective infection concentration was determined by LacZ Adenovirus and 75 m.o.i was found the most optimal. Conclusion: BDNF-Ad transfected Schwann cells successfully regenerated the 14mm nerve gap which was connected with calcium phosphate coated Millipore filter. The BDNF-Ad group showed better results compared with Schwann cells only group and control group in aspect to sciatic function index, electrophysiologic measurements and histomorphometric analysis.

Changes in Quality of Boiled Neverita didyma as a Function of Autoclaving Conditions (큰구슬 우렁이 (Neverita didyma) 보일드 통조림의 가열살균(加熱殺菌) 조건(條件)에 따른 품질변화(品質變化))

  • Lee, Keun-Woo;Ryu, Hong-Soo;Joo, Hyen-Kyu
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.13 no.3
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    • pp.231-237
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    • 1984
  • Changes in available lysine and water soluble proteins were checked to obtain the desirable condition of processing for boiled Neverita didyma under the various autoclaving temperatures and times. It was also carried out to assess the affect of heat treatments upon the solubility of coagulable substances in boiled products. In order to evaluate the nutritional quality of processed Neverita didyma under the highest available lysine retention and without bacteria, it was studied the value of pepsin-pancreatin digest residue index in comparison with unprocessed (raw) material. The crude protein content of raw material was higher than that of the other mollusks, while the content of crude fat was showing lower value. It was noticed that the higher contents of coagulable substances and water soluble proteins in processed Neverita didyma were obtained under the conditions, retort temperature at $120^{\circ}C$ above, and 40-60 min. sterilization. After the pannel test, the coagulable substances were not found below the level of $0.40{\pm}0.03$ gram nitrogen/ml of juice. The remarkable retention of available lysine (FDNB-reactive lysine) was resulted in the conditions of autoclaving at $115^{\circ}C$ for 40 minutes in boiled Neverita didyma products, and that processing condition was coincide with the condition of commercial sterilization for boiled top shell. It was revealed that the boiled meat of Neverita didyma showed the higher PPDRI(65.85) than that of raw material (63.16).

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Isolation and Characterization of mas1+ of Schizosaccharomyces pombe, a Homologue of Human CIP29/Hcc-1 Involved in the Regulation of Cell Division (세포분열에 관여하는 인간의 CIP29/Hcc1 유전자와 상동성을 가지는 분열형 효모의 새로운 유전자 mas1+의 특성분석)

  • Cha, Jae-Young;Shin, Sang-Min;Ha, Se-Eun;Lee, Jung-Sup;Park, Jong-Kun
    • Journal of Life Science
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    • v.21 no.12
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    • pp.1666-1677
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    • 2011
  • The regulation of gene expression plays an important role in cell cycle controls. In this study, a novel gene, the $mas1^+$($\underline{mi}$tosis $\underline{as}$sociated protein) gene, a homolog of human CIP29/Hcc1, was isolated and characterized from fission yeast Schizosaccharomyces pombe (S. pombe) using a gene-specific polymerase chain reaction. The isolated gene contained a complete open reading frame capable of encoding 245 amino acid residues with a typical promoter, as judged by nucleotide sequence analysis. It was also found that a PCB ($\underline{p}$ombe cell $\underline{c}$ycle $\underline{b}$ox) is located in the promoter region, which controls M-$G_1$ specific transcription in S. pombe. The quantitative analysis of the $mas1^+$ transcript against $adh1^+$ showed that the pattern of expression is similar to that of the septation index. Cytokinesis of mas1 mutant was greatly delayed at $25^{\circ}C$ and $36^{\circ}C$, and a large number of multi-septate cells were produced. The mas1 mutant had 2C, 4C and 6C DNA contents, as determined by FACS analysis. In addition, the number of multi-septate cells significantly increased. When cells were cultured in nitrogen starvation medium to increase proliferation, the abnormal phenotypes of mas1 mutant dramatically increased. These phenotypes could be rescued by an overexpression of the $mas1^+$ gene. The mas1 protein localized in the nuclei of S. pombe and human HeLa cells, as evidenced by Mas1-EGFP signals. The abnormal growth pattern and the morphology of mas1 mutant were complemented by a plasmid carrying human CIP29/Hcc-1cDNA. In addition, CIP29 /Hcc-1 transcript level increased in active cell proliferation stages in the developing mouse embryos. These results indicate that the $mas1^+$ ishomologous to the human CIP29/Hcc1 gene and is involved in cytokinesis and cell shape control.