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Ti-6Al-4V 합금의 표면개질에 의한 calcium phosphate의 형성
박은진,김도균,김교한,고 융부,김형일,정용수 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.1
The purpose of this study os to investigate the formation of calcium phosphate on Ti-6Al-4V surface on aqueous solutions containing phosphate and calcium ions. The surface of Ti-6Al-4V specimens were treated in phosphate buffered solutions for 3 days followed by immersion in calcium phosphate buffered solutions for 10 days. These solutions have different concentration and pH(pH 5.8, 7.0, 8.0) one another. Then, the specimens treated with P and Ca ions and control group without surface treatment were immersed in Hanks' balanced solution for 30 days to make sure the effectiveness of this surface treatment. All specimens were characterized using scanning electron microscopy(SEM), X-ray diffractometry(XRD) and Fourier transform infrared spectrophotometry(FT-IR). The amount of crystallized particles formed on the specimens by surface treatment was significantly increased in all experimental conditions as compared with that immersed only in Hanks' solution. Dense granular shaped precipitates were observed on the surface and these particles were recognized as calcium phosphate similar to HA(hydroxyapatite) or TCP(tri-calcium phosphate).
박종진,박정원,박성호,박주명,권태경,김성교 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.2
The aim of this study was to investigate the effect of light irradiation modes on polymerization shrinkage, degree of cure and microleakage of a composite resin. VIP^™ (Bisco Dental Products, Schaumburg, IL, USA) and Optilux 501^™(demetron/ Kerr, Danbury, CT, USA) were used for curing Filtek^™ Z-250(3M Dental Products, St. Paul., MN, USA) composite resin using following irradiation modes: VIP^™ (Bisco) 200mW/cm^2 (V2), 400mW/cm^2 (V4), 600mW/cm^2 (V6), Pulse-delay (200 mW/cm^2 3 seconds, 5 minutes wait, 600mW/cm^2 30seconds, VPD) and Optilux 501^™ (Demetron/Kerr) C-mode (OC), R-mode (OR). Linear polymerization shrinkage of the composite specimens were measured using Linometer (R&B, Daejeon, Korea) for 90 seconds for V2, V4, V6, OC, OR groups and for up to 363 seconds for VPD group (n=10, each). Degree of conversion was measured using FTIR spectrometer (IFS 120 HR, Bruker Karlsruhe, Germany) at the bottom surface of 2 mm thick composite specimens. V2, V4, V6, OC groups were measured separately at five irradiation times (5, 10, 20, 40, 60 seconds) and Or, VPD groups were measured in the above mentioned irradiation modes (n=5, each). Microhardness was measured using Digital microhardness tester (FM7, Future-Tech Co., Tokyo, Japan) at the top and bottom surfaces of 2mm thick composite specimens after exposure to the same irradiation modes as the test of degree of conversion(n=3, each). For the microleakage test, class V cavities were prepared on the distal surface of the ninety extracted human third molars. The cavities were restored with one of the following irradiation modes: V2/60 seconds. V4/40 seconds, V6/30 seconds, VPD, OC and OR. Microleakage was asessed by dye penetration along enamel and dentin marigns of cavities. Mean polymerization shrinkage, mean degree of conversion and mean microhardness values for all groups at each time were analyzed using one-way ANOVA and Duncan's multiple range test, and using chisquare test for microleakage values. The results were as follows: ·Polymerization shrinkage was increased with higher light intensity in groups using VIP^™(Bisco) : the highset with 600mW/cm^2, followed by Pulse-delay, 400mW/cm^2 and 200mW/cm^2 groups. The degree of polymerization shrinkage was higher with Continuous mode than with Ramp mode in groups using Optilux 501^™ (Demetron/Kerr). ·Degree of conversion and microhardness values were higher with higher light intensity. The final degree of conversion was in the range of 44.7 to 54.98% and the final microhardness value in the range of 34.10 to 56.340. ·Microleakage was greater in dentin margin than in enamel margin. Higher light intensity showed more microleakage in dentin margin in groups using VIP^™ (Bisco). The microleakage was the lowest with Continuous mode in enamel margin and with Ramp mode in dentin margin when Optilux 501^™ (Demetron/Kerr) was used.
Jeong, Jae-Kyo,Lee, You-Jin,Jeong, Seung Yol,Jeong, Sooyeon,Lee, Geon-Woong,Park, Sang-Youel DOVE MEDICAL PRESS 2017 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.12 No.-
<P>Graphene oxide (GO) is a nanomaterial with newly developing biological applications. Autophagy is an intracellular degradation system that has been associated with the progression of neurodegenerative disorders. Although induction of autophagic flux by GO has been reported, the underlying signaling pathway in neurodegenerative disorders and how this is involved in neuroprotection remain obscure. We show that GO itself activates autophagic flux in neuronal cells and confers a neuroprotective effect against prion protein (PrP) (106–126)-mediated neurotoxicity. GO can be detected in SK-N-SH neuronal cells, where it triggers autophagic flux signaling. GO-induced autophagic flux prevented PrP (106–126)-induced neurotoxicity in SK-N-SH cells. Moreover, inactivation of autophagic flux blocked GO-induced neuroprotection against prion-mediated mitochondrial neurotoxicity. This is the first study to demonstrate that GO regulates autophagic flux in neuronal cells, and that activation of autophagic flux signals, induced by GO, plays a neuroprotective role against prion-mediated mitochondrial neurotoxicity. These results suggest that the nanomaterial GO may be used to activate autophagic flux and could be used in neuroprotective strategies for treatment of neurodegenerative disorders, including prion diseases.</P>
CASE REPORT : Primary Pulmonary Malignant Melanoma: An Unexpected Tumor
( Kyo Bum Hwang ),( Ki Eun Hwang ),( Jae Wan Jung ),( Su Jin Oh ),( Mi Jeong Park ),( Young Hoon Jeong ),( Keum Ha Choi ),( Eun Taik Jeong ),( Hak Ryul Kim ) 대한결핵 및 호흡기학회 2015 Tuberculosis and Respiratory Diseases Vol.78 No.3
Malignant melanoma occurs most frequently on the skin. However, it can also arise in other organs and tissues of the body. Primary pulmonary malignant melanoma is a very rare non-epithelial neoplasm accounting for 0.01% of all primary pulmonary tumors. The treatment of choice is surgical resection of the tumor with an oncologically adequate margin as in lobectomy or pneumonectomy. The prognosis of this condition is rather poor. Based on previous data, its 5-year survival is at least 10%. Here, we report a case of an 82-year-old woman whose primary pulmonary melanoma was detected incidentally.
Jeong, Jun-Kyo,Yun, Ho-Jin,Yang, Seung-Dong,Eom, Ki-Yun,Chea, Seong-Won,Park, Jeong-Hyun,Lee, Hi-Deok,Lee, Ga-Won Elsevier S.A. 2017 Thin Solid Films Vol.638 No.-
<P><B>Abstract</B></P> <P>In this study, Al-doped zinc oxide (AZO) thin films with different Al concentrations fabricated by atomic layer deposition are investigated to determine the Al doping effect for AZO/ZnO double-stacked active layer thin-film transistor (TFT) applications. The AZO films are analyzed by X-ray diffraction, photoluminescence, and X-ray photoelectron spectroscopy, which show that the Al dopants affect the crystallinity, including the crystal direction and grain size, and reduce the deep trap sites such as oxygen vacancies (V<SUB>O</SUB>). The optimized Al doping concentration is about 2%. TFTs with an AZO (2%)/ZnO double-stacked active layer are fabricated and shown to exhibit a lower threshold voltage (V<SUB>th</SUB>), subthreshold slope, and V<SUB>th</SUB> shift under a positive gate-bias stress compared to ZnO single-layer devices. In the case of the on-current, however, the AZO stacked devices exhibit a smaller value. These electrical characteristics can be explained by V<SUB>O</SUB> suppression and altered crystal properties due to Al doping. For the field-effect mobility, the temperature dependence also reveals that the main transport mechanisms are thermionic and thermal field emission over the grain boundary in the AZO stacked devices. These results indicate that the AZO film properties depend strongly on the Al concentration and hence the ZnO-based devices can be optimized for specific application by Al doping.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AZO thin films with different Al doping concentration were analyzed. </LI> <LI> Through physical analysis, 2% AZO showed the best characteristics. </LI> <LI> The use of AZO showed improved stability through gate bias stress measurement. </LI> <LI> The main transport mechanism was analyzed through temperature dependence of mobility. </LI> <LI> The main transport mechanism is thermionic and thermal field emission. </LI> </UL> </P>
Jeong, Hyeon Jin,Yoo, Ran Ji,Kim, Jin Kwan,Kim, Min Hwan,Park, Su Hong,Kim, Haebin,Lim, Jae Wook,Do, Sun Hee,Lee, Kyo Chul,Lee, Yong Jin,Kim, Dong Wook Elsevier 2019 Biomaterials Vol.199 No.-
<P><B>Abstract</B></P> <P>We introduce an efficient cell tracking imaging protocol using positron emission tomography (PET). Since macrophages are known to home and accumulate in tumor tissues and atherosclerotic plaque, we design a PET imaging protocol for macrophage cell tracking using aza-dibenzocyclooctyne-tethered PEGylated mesoporous silica nanoparticles (DBCO-MSNs) with the short half-life F-18-labeled azide-radiotracer via an in vivo strain-promoted alkyne azide cycloaddition (SPAAC) covalent labeling reaction inside macrophage cells in vivo. This PET imaging protocol for in vivo cell tracking successfully visualizes the migration of macrophage cells into the tumor site by the bioorthogonal SPAAC reaction of DBCO-MSNs with [<SUP>18</SUP>F]fluoropentaethylene glycolic azide ([<SUP>18</SUP>F]<B>2</B>) to form <SUP>18</SUP>F-labeled aza-dibenzocycloocta-triazolic MSNs (<SUP>18</SUP>F-DBCOT-MSNs) inside RAW 264.7 cells. The tissue radioactivity distribution results were consistent with PET imaging findings. In addition, PET images of atherosclerosis in ApoE<SUP>−/-</SUP> mice fed a western diet for 30 weeks were obtained using the devised macrophage cell-tracking protocol.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>