• Applied Chemistry for Engineering
• /
• v.27 no.6
• /
• pp.599-605
• /
• 2016

Recently, photodynamic and photothermal therapies have received increasing attention as an effective cancer treatment. In this study, a gold nanorod (AuNR) colloidal solution was synthesized as a hyperthermia agent for photothermal therapy and also modified with photosensitizer (PS) for photodynamic therapy. PEG (polyethylene glycol) and FA (folic acid) ligand were also introduced into AuNR for the long circulation in human body and efficient targeting of cancer cells, respectively and AuNRs were modified with FA-PEG and poly-${\beta}$-benzyl-L-aspartate (PBLA) block copolymers through a 3,4-dihydroxy hydrocinnamic acid (HCA) linker. A series of AuNRs with various aspect ratios were synthesized by controlling the feeding ratio of $AgNO_3$. The physicochemical property and morphology of synthesized AuNR100 and FA-PEG-$P(Asp)_{50}$-HCA-AuNR100 were analyzed by UV-visible spectrophotometer, $^1H$ NMR, XPS measurements, TEM. The surface modified AuNR carrier with biocompatibility could be applied for the effective diagnosis as well tumor phototherapy.

• Journal of Periodontal and Implant Science
• /
• v.39 no.2
• /
• pp.119-128
• /
• 2009

Purpose: The aim of this study was to evaluate the stemness of cells from canine dental tissues and bone marrow. Methods: Canine periodontal ligament stem cells (PDLSC), alveolar bone stem cells (ABSC) and bone marrow stem cells(BMSC) were isolated and cultured. Cell differentiations (osteogenic, adipogenic and chondrogenic) and surface antigens (CD146, STRO-1, CD44, CD90, CD45, CD34) were evaluated in vitro. The cells were transplanted into the subcutaneous space of nude mice to assess capacity for ectopic bone formation at 8 weeks after implantation. Results: PDLSC, ABSC and BMSC differentiated into osteoblasts, adipocytes and chondrocytes under defined condition. The cells expressed the mesenchymal stem cell markers differently. When transplanted into athymic nude mice, these three kinds of cells with hydroxyapatite /${\beta}$- tricalcium phosphate (HA/TCP) carrier showed ectopic bone formation. Conclusions: This study demonstrated that canine dental stem cells have stemness like bone marrow stem cells. Transplantation of these cells might be used as a therapeutic approach for dental stem cell-mediated periodontal tissue regeneration.

• KSBB Journal
• /
• v.22 no.6
• /
• pp.409-413
• /
• 2007

Polydiacetylene(PDA)-based sensors possess a number of properties that can be successfully applied for label-free detection system. PDA is one of the most attractive color-generating materials, with growing applications as sensors. Here we introduce various PDA-based devices, used as biosensor, chemosensor, thermosensor, and optoelectronics sensor. In general, PDA liposomes and films are closely packed and properly designed for polymerization via 1,4-addition reaction to form an ene-yne alternating polymer chain. PDA-based two/three dimensional structures have been used for colorimetric or fluorescent devices, sensing biological as well as chemical components. This color-generating material also present a very high charge carrier mobility, allowing its application as field-effect transistor (FET). The immobilized PDA structures or films have distinct advantages for the detection of low concentration target molecules over the aqueous solution-based detection systems. In the present review, reported detection methods by using various PDA structures are summarized with updated references.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.2
• /
• pp.430-439
• /
• 2004

This paper describes a design of 8192/2048-point FFT/IFFT processor (CFFT8k2k), which performs multi-carrier modulation/demodulation in OFDM-based DVB-T receiver. Since a large size FFT requires a large buffer memory, two design techniques are considered to achieve memory-efficient implementation of 8192-point FFT/IFFT. A hybrid structure, which is composed of radix-4 single-path delay feedback (R4SDF) and radix-4 single-path delay commutator (R4SDC), reduces its memory by 20% compared to R4SDC structure. In addition, a memory reduction of about 24% is achieved by a novel two-step convergent block floating-point scaling. As a result, it requires only 57% of memory used in conventional design, reducing chip area and power consumption. The CFFT8k2k core is designed in Verilog-HDL, and has about 102,000 Bates, RAM of 292k bits, and ROM of 39k bits. Using gate-level netlist with SDF which is synthesized using a $0.25-{\um}m$ CMOS library, timing simulation show that it can safely operate with 50-MHz clock at 2.5-V supply, resulting that a 8192-point FFT/IFFT can be computed every 164-${\mu}\textrm{s}$. The functionality of the core is fully verified by FPGA implementation, and the average SQNR of 60-㏈ is achieved.

• Journal of Adhesion and Interface
• /
• v.22 no.2
• /
• pp.57-62
• /
• 2021

Recently, the atomically thin two-dimensional transition-metal dichalcogenides (TMDs) have received considerable attention for the application to next-generation semiconducting devices, owing to their remarkable properties including high carrier mobility. However, while a technique for growing graphene is well matured enough to achieve a wafer-scale single crystalline monolayer film, the large-area growth of high quality TMD monolayer is still a challenging issue for industrial application. In order to enlarge the size of single crystalline MoS₂ monolayer, here, we systematically investigated the effect of process parameters in molten-salt-assisted chemical vapor deposition method. As a result, with optimized process parameters, we found that single crystalline monolayer MoS₂ can be grown as large as 420 ㎛.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.1
• /
• pp.28-36
• /
• 2011

Diblock copolymers composed of poly(${\varepsilon}$-caprolactone) (PCL) and poly(N,N-dimethylamino-2-ethyl methacrylate) (PDMAEMA), or methoxy polyethylene glycol(PEG), were synthesized via a combination of ring-opening polymerization and atom-transfer radical polymerization in order to prepare polymeric nanoparticles as an antifungal drug carrier. Amphotericin B (AmB), a natural antibiotic, was incorporated into the polymeric nanoparticles. The physical properties of AmB-incorporated polymeric nanoparticles with PCL-b-PDMAEMA and PCL-b-PEG were studied in relation to morphology and particle size. In the aggregation state study, AmB-incorporated PCL-b- PDMAEMA nanoparticles exhibited a monomeric state pattern of free AmB, whereas AmB-incorporated PCL-b- PEG nanoparticles displayed an aggregated pattern. In in vitro hemolysis tests with human red blood cells, AmBincorporated PCL-b-PDMAEMA nanoparticles were seen to be 10 times less cytotoxic than free AmB (5 ${\mu}g$/ml). In addition, an improved antifungal activity of AmBincorporated polymeric nanoparticles was observed through antifungal activity tests using Candida albicans, whereas polymeric nanoparticles themselves were seen not to affect activity. Finally, in vitro AmB release studies were conducted, proving the potential of AmB-incorporated PCL-b-PDMAEMA nanoparticles as a new formulation candidate for AmB.

• Journal of Korean Society for Atmospheric Environment
• /
• v.34 no.3
• /
• pp.393-405
• /
• 2018

Volatile organic compounds (VOCs) are representative air pollutants due to their detrimental effects on human health and their role in formation of secondary organic aerosols. Assessments and monitoring programs of VOCs using periodic grab sampling like Tedlar bags, canisters, and sorbent traps provide limited information, often with delay times of days or weeks. Selected ion flow tube mass spectrometry (SIFT-MS) is an emerging analytical technique for the real-time quantification of VOCs in air. It relies on chemical ionization of the VOCs molecules in air introduced into helium carrier gas using $H_3O^+$, $NO^+$, and $O_2{^+}$ precursor ions. Real-time monitoring method of 60 VOCs in the ambient air was developed using TO-15 standard gas mixture. Calibration curves, method detection limit, and quantitation reproducibility of the target compounds were tested. Dynamic dilution system was used to dilute standard gas from 0.174 ppbv to 100 ppbv, where calibration curves showed good linearity with $r^2$> 0.95 in all target analytes. Limit of detection (LOD) all compounds were sub ppbv, and some halogenated compounds showed pptv levels. Seven consecutive analyses of target compounds showed good repeatability with relative standard deviation of less than 10%. One day monitoring of VOCs in ambient air was conducted in Geoje. Average concentration of target VOCs in Geoje were relatively lower than other regions, among which formaldehyde showed the highest concentration ($15.4{\pm}5.78ppbv$). SIFT-MS provided good temporal resolution data (1 data per 3.2 minute), which can be used for identifying ephemeral short-term event. It is expected that SIFT-MS will be a versatile monitoring platform for VOCs in ambient air.

• Journal of Korean Ophthalmic Optics Society
• /
• v.15 no.4
• /
• pp.319-328
• /
• 2010

Purpose: To understand the status and actual condition of clinical practice in ophthalmic optics and offer a effective operation plan and improvement of quality of clinical practice. Methods: The school survey were investigated from 30 ophthalmic optics school and student survey were investigated from 161 students among these 4 schools. Results: 'No specific program for clinical practice' were 60.7%. Most schools apply clinical practice to credit (96.4%) but naming of subject and credit were varied in each school. 'Communication skill' was most difficult task and 'cleaning and arrangement of frame and stuff' were major task to students during clinical practice. Best benefits through clinical practice was 'knowing real status of optical business'. Comparison in carrier preference, optical shop and spectacles/contact lens company were decreased and eye hospital and norelation work were increased after clinical practice. Conclusions: Wide study on effective operation plan for clinical practice in ophthalmic optics and on the improvement of students' satisfaction and close cooperation and interest were needed between schools and clinical practice places.

• The Korean Journal of Nuclear Medicine
• /
• v.36 no.2
• /
• pp.102-109
• /
• 2002

Purpose : In gene therapy, tumor cells expressing the herpes simplex virus thymidine kinase are sensitive to prodrugs. Potential prodrugs IVDU and IVFRU were synthesized and radiolabeled with radioiodine for noninvasive imaging of herpes simplex virus type 1 gene expression. Material and Methods : 5-(2-trimethysilyl) vinyl-2'-deoxyuridine and 5-(2-trimethylsilyl)vinyl-2'-fluoro-2'-deoxyuridine, precursors of 5-(2--iodo)viny l-2'-deoxy uridine(IVDU) and 5-(2-iodo)-2'-vinyl-2'-deoxy-2'-fluororibofuranosyl uracil(IVFRU), were synthesized from reaction of trans-1-trimethylsillyl-2-tri-n-butylstannylethylene with 5-iodo-2'-deoxyuridine and 5-iodo-2'-fluoro-2'-deoxyuridine, respectively, on the condition of Pd catalyst. These precursors were separated from reaction mixture by silica gel column chromatography method. Each precursor was radioiodinated with radioiodine by mixing with ICI oxidizing agent. These radioiodinated compounds were purified with HPLC. Radiohalogen exchange has been shown to be effective for the synthesis of products with lower specific activity. Similarly, carrier-added and high specific activity products have been isolated in respectable radiochemical yields using ICI method. Results : Synthetic yield of precursors, IVDU and IVFRU were 43% and 18%, respectively. Radiochemical purity of both compunds was over 98%. Conclusion : We synthesized precursors of IVDU and IVFRU for monitoring of HSV1-tk gene expression. Radiotracers were radioiodinated with high radiolabeling yield by ICI method.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.3 no.2
• /
• pp.125-130
• /
• 1993

We has made 2-zone vertical electric furnace and has been grown CdS single crystal by sublimation method in crystal growth tube with tail tube without seed crystal for growth. While it has been growing, temperature difference ${\Delta}T$ of source and growth part has nearly agreed with theoritical value $14.7^{\circ}C$and experimental value $15^{\circ}C$ Then, crystal of best quality has been grown, when temperature of tail tube has been $110^{\circ}C$, in spite of quickly pulling up crystal growth tube a degree O.38mm per hour. The grown crystal have had hexagonal structure and single crystal with c-axis to length of crystal growth tube from X- ray diffraction pattern of powder method and Laue pattern of back reflection Laue method. Also, the mobility and carrier density from Hall effect measurement have been $316cm^2/V{\cdot}sec$ and $2.90{\times}10^{16}cm^{-3}$ at the room temperature, respectively.