N-doped ZnS nanoparticles with wurtzite phase was synthesized at 150 °C, derived from an inorganic−organic complex, ZnS·(piperazine)0.5. The metastable ZnS·(piperazine)0.5 nanohybrid materials could ...be described as the layered structure where wurtzite ZnS layers are connected to each other through the bondings of nitrogen atoms in piperazine. It was found that with the progress of the synthetic reaction, the interlayer piperazine molecules were moved out of the layers and the phase was transformed into wurtzite ZnS. Interestingly, nitrogen atoms in piperazine could be doped into ZnS in the extraction of the interlayer molecules. Phase transition was studied by using various techniques, including powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and high-resolution scanning transmission electron microscopy (HR-STEM). The N-doping was characterized with UV−vis spectroscopy, and experimental and theoretical analyses of X-ray absorption structure (XANES). The N-doped ZnS was applied to the photocatalytic degradation of dye under visible light irradiation.
Matrix metalloproteinases (MMPs) play an important role in tissue remodeling during normal physiological situations and pathological implications such as tumor invasion and metastasis. MMP inhibitors ...were screened from extracts of medicinal herbs by an enzymatic assay using the MMP-14 catalytic domain. Among samples tested, a methanol extract of the root of Dalbergia odorifera T. CHEN (Leguminosae) showed the strongest inhibitory activity. The inhibitory component was purified through fractionation methods and identified as fisetin, abundant in many fruits and vegetables. In addition to inhibition of MMP-14, fisetin inhibits MMP-1, MMP-3, MMP-7, and MMP-9, more efficiently than a naturally occurring MMP inhibitor tetracycline. Fisetin dose-dependently inhibits proliferation of fibrosarcoma HT-1080 cells and human umbilical vascular endothelial cells (HUVECs), MMP-14-mediated activation of proMMP-2 in HT-1080 cells, invasiveness of HT-1080 cells, and in vitro tube formation of HUVECs. Therefore, fisetin could be valuable as a chemopreventive agent against cancer and a lead compound for development of therapeutic MMP inhibitors.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
The applicable scope of adhesives in the current society is broad and currently, several types of PVAc resin are sold in the market for adhesives. PVAc resin is primarily used for wood works and ...paper adhesion. However, the PVAc resin itself has the disadvantages that its viscosity is highly temperature- dependent and the work condition and viscosity get worse at the low temperature in the winter seasons. Although phthalate-based plasticizer is used to complement these disadvantages, adhesion strength and heat-resistance are weakened by adding the phthalate-based plasticizer and in the winter period, the amount of quantity should be increased. Also in a high-density product, it worsens the work condition by causing a rise of viscosity and delays curing and in a low-density product, it worsens the storage stability by causing separate precipitation. In addition to these, the phthalate-based plasticizer as a material of causing environmental hormones is currently restricted in the advanced countries for its amount of use and also in the domestic market, it is necessary to prepare for the situation. This study has not only eliminated the disadvantages of PVAc resin emulsion without adding a phthalate-based plasticizer of causing these problems, but also synthesized the PVAc resin for timber adhesion that is excellent in woodwork, thermal-resistance, water-resistance, storage stability, and adhesion performance. As the result, it has proven an excellent performance in thermal resistance, water resistance, storage stability, and minimum film forming temperature.
Highly efficient tree branch-shaped CuO photocathodes are fabricated using the hybrid microwave annealing process with a silicon susceptor within 10 minutes. The unique hierarchical, one-dimensional ...structure provides more facile charge transport, larger surface areas, and increased crystallinity and crystal ordering with less defects compared to irregular-shaped CuO prepared by conventional thermal annealing. As a result, the photocathode fabricated with the tree branch-shaped CuO produces an unprecedently high photocurrent density of −4.4 mA cm
−2
at 0 V
RHE
under AM 1.5 G simulated sunlight compared to −1.44 mA cm
−2
observed for a photocathode fabricated by thermal annealing. It is also confirmed that stoichiometric hydrogen and oxygen are produced from photoelectrochemical water splitting on the tree branch-shaped CuO photocathode and a platinum anode.
The tree branch-shaped CuO, fabricated using the hybrid microwave annealing (HMA) process with a silicon susceptor shows excellent photoelectrochemical water reduction activity.
Three dopants, HNO sub(3), AuCl sub(3), and RhCl sub(3) have been employed to fabricate p-type graphene layers with varying doping concentration and subsequently compare their structural, optical, ...and electrical properties. By RhCl sub(3) doping, the sheet resistance is most stable as time elapses and the Raman frequency/work function (thus Dirac point) are most doping-sensitive without big degradation of transmittance and hole mobility. The C=C/C-C bonds intensity ratio (I sub(c=c)/I sub(c-c)) in the C 1s X-ray photoelectron spectra increases in all doped samples with the change being largest by RhCl sub(3) doping, another evidence for the p-type doping by electron transfer from graphene sheets to the adsorbates. The largest I sub(c=c)/I sub(c-c) ratio may indicate the C atoms are most fully double-bonded even though a lot of electrons are leaked out from graphene, thereby making the graphene layer least defective, consistent with the minimized reduction of the transmittance and the hole mobility by RhCl sub(3) doping.
We have developed the high‐resolution auto‐stereoscopic 3D display for the first time in the world. For this, we suggested time division(TD) parallax barrier method. For the time division ...multiplexing image separation, we have adapted 2.2″ AMOLED panel for Imager and we have fabricated fast driving circuit, which operated in more than 240Hz frame rate. Also we have designed and fabricated OCB mode LC barrier shutter for fast responses. We can see 3‐D image at 300mm viewing distance with 3‐D resolution that is same as 2‐D resolution.
The aim of this research was to prepare microparticulate systems based on poly (lactide-co-glycolide)(PLGA) for the local release of ipriflavone in order to reduce bone loss. We developed the IP ...loaded PLGA microspheres using relatively simple oil-in-water(O/W) solvent evaporation method. HPLC was used to perform the in vitro release test of IP and morphology of cell attached on the micro-spheres was investigated using SEM. Cytotoxicity was assayed by cell counting kit-8 (CCK-8) test. Osteogenic differential cells were analyzed by ALP activity. Through RT-PCR analysis, we observed osteocalcin, ALP, and Type I collagen mRNA expression. The release of IP in vitro was more prolonged over 42 days and IP/PLGA microspheres showed the improvement on the cell proliferation, ALP activity and RT-PCR comparing with control (only PLGA). This initial research will be used to direct future work involved in developing this composite injectable bone tissue engineering system. 골 결손 치료를 위해 생분해성 고분자인 PLGA에 골다공증 치료제인 이프리플라본(IP)을 함유한 미립구를 O/W 유화 용매 증발법으로 제조하였으며, 생체외 방출실험에서 IP 방출량은 HPLC로 분석하였다. SEM을 이용하여 미립구에 부착된 세포의 거동을 확인하였으며, IP가 세포에 미치는 독성평가는 CCK-8 분석방법을 이용하여 측정하였다. 골 형성 지표인 ALP 활성도를 측정하였으며, 배양된 BMSCS의 골세포로의 표현형을 확인하기 위하여 RT-PCR을 수행하였다. 방출결과에서 IP 방출은 거의 40일 이상으로 지속적이었으며, IP를 함유한 미립구에서의 세포의 부착, 성장 등이 잘 이루어짐을 확인하였고, ALP 활성도 및 RT-PCR 분석결과에서도 단독의 PLGA 미립구보다 IP를 함유한 미립구에서의 값이 더 높은 것을 확인할 수 있었다. 본 실험결과를 바탕으로 향후 서방성 제제화에 있어서 IP/PLGA 미립구를 응용하게 되면 국소지향성 골분화 주사용 지지체로서 중요한 역할을 할 것으로 보인다.
Alginate/PLGA 미립구에 대한 인간디스크 세포 부착 효과 이준희(Jun Hee Lee); 장지욱(Ji Wook Jang); 소정원(Jeong Won So) ...
Porrimer (Seṅur),
2009, 2009-01, Letnik:
33, Številka:
1
Journal Article
Recenzirano
Odprti dostop
PLGA microspheres have been known as an injectable system for tissue engineering. The purpose of this study was to investigate the condition of emulsion formation and cell adhesion on the microsphere ...surface. BSA-loaded PLGA microsphere was fabricated by oil-in-water (O/W) and water-in-oil-in-water (W/O/W) solvent evaporation method. Sodium alginate was dissolved in water phase to control initial burst release and to improve lag time by PLGA bulk degradation. In addition, the morphology of cells attached on the micro spheres was studied using a scanning electron microscopy (SEM). Cellular proliferation behavior of human disc cells cultivated on PLGA micro spheres was analyzed using a MTT assay. MTT assay revealed that the cells can attach and proliferate on PLGA microspheres. According to these results, we concluded that BSA -loaded alginate/PLGA microspheres can be used as an injectable system for tissue engineering application. PLGA미립구는 주사제형과 같은 형태로 조직공학적 응용에 이용할 수 있다. 본 연구에서는 미립구 제조시 에밀젼 형성조건에 대한 영향과 미립구 표면에 세포를 부착시키는 방법에 대하여 연구하였다. BSA를 함유하는 PLGA미립구는 수중유형(O/W)과 수중유중수형(W/O/W) 용매증발법을 이용하여 제조하였다. 미립구의 초기방출효과제어와 PLGA분해의 과정에서 발생되는 지연시간을 개선시키기 위하며 알긴산나트륨을 수상에 용해시켜 사용하였다. 미립구에 부착된 세포의 형태를 전자주사현미경(SEM)을 이용하여 분석하였고 PLGA미립구에 배양된 인간디스크세포의 증식은 MTT분석을 이용하였으며 이를 통하여 PLGA미립구 표면에 세포가 부착되었음을 확인하였다. 본 연구는 BSA가 함유된 알긴산/PLGA미립구를 이용하여 조직공학적 응용이 가능한 주사제형으로서의 가능성을 제안하였다.
탈미네랄화된 골분을 이용한 스폰지의 제조 및 특성 분석 장지욱(Ji Wook Jang); 백미옥(Mi Ock Baek); 김순희(Soon Hee Kim) ...
Porrimer (Seṅur),
2009, Letnik:
33, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Demineralized boneparticle (DBP) has been widely used as and a powerful promoter of new bone growth. In this study, DBP sponges were chemically crosslinked and characterized for the potential ...application of tissue engineered scaffolds. The DBP sponges prepared by crosslinking with EDC. 0.1, 0.2 or 0.3% pepsin was applied to DBP dissolved in 3% (v/v) acetic acid aqueous solution for 48 hrs. The prepared sponges were crosslinked by 1, 5, 10, 50 or 100 mM of EDC solution concentration and then were lyophilized. The DBP sponges were characterized by SEM, FT-IR and DSC and analyzed in terms of their porosity and water absorption ability. The cellular viability and proliferation were assayed by MTT assay. Our investigation revealed that 0.2$\sim$0.3% of pepsin and 50$\sim$100 mM of EDC produced DBP sponges with good physical characteristics. In conclusion, DBP sponge prepared under these conditions is potentially useful for the applications of tissue construction. 탈미네랄화된 골분(DBP)은 생체활성 천연재료로서 골을 형성시키는 유도인자로 널리 사용되고 있다. 본 연구에서는 DBP 스폰지를 펩신의 농도와 가교제의 농도에 따라 그 특성을 분석함으로써 조직공학적 지지체로의 응용 가능성을 확인하였다. DBP를 3% 아세트산 용액에 48시간동안 용해시킬 시 0.1, 0.2 및 0.3% 펩신을 첨가하였고, 가교시 1, 5, 10, 50 및 100 mM의 EDC를 적용하였다. 이를 전자주사현미경, 시차주사열량계, 적외선 분광기, 다공도 및 흡수성 실험을 통해 특성분석하였으며 세포의 증식률은 MTT 분석으로 확인하였다. 이러한 결과를 통해 펩신의 농도로는 0.2$\sim$0.3%가, 가교제의 농도는 50$\sim$100 mM에서 물리화학적 특성이 우수한 것으로 판단되었고, 이러한 조건으로 제조된 DBP 스폰지는 조직 공학적 지지체로 유용하게 응용될 수 있을 것이다.
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