• Asian Pacific Journal of Cancer Prevention
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• 제15권1호
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• pp.49-54
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• 2014

Background: Hydrogels are a class of polymers that can absorb water or biological fluids and swell to several times their dry volume, dependent on changes in the external environment. In recent years, hydrogels and hydrogel nanocomposites have found a variety of biomedical applications, including drug delivery and cancer treatment. The incorporation of nanoparticulates into a hydrogel matrix can result in unique material characteristics such as enhanced mechanical properties, swelling response, and capability of remote controlled actuation. Materials and Methods: In this work, synthesis of hydrogel nanocomposites containing magnetic nanoparticles are studied. At first, magnetic nanoparticles ($Fe_3O_4$) with an average size 10 nm were prepared. At second approach, thermo and pH-sensitive poly (N-isopropylacrylamide -co-methacrylic acid-co-vinyl pyrrolidone) (NIPAAm-MAA-VP) were prepared. Swelling behavior of co-polymer was studied in buffer solutions with different pH values (pH=5.8, pH=7.4) at $37^{\circ}C$. Magnetic iron oxide nanoparticles ($Fe_3O_4$) and doxorubicin were incorporated into copolymer and drug loading was studied. The release of drug, carried out at different pH and temperatures. Finally, chemical composition, magnetic properties and morphology of doxorubicin-loaded magnetic hydrogel nanocomposites were analyzed by FT- IR, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM). Results: The results indicated that drug loading efficiency was increased by increasing the drug ratio to polymer. Doxorubicin was released more at $40^{\circ}C$ and in acidic pH compared to that $37^{\circ}C$ and basic pH. Conclusions: This study suggested that the poly (NIPAAm-MAA-VP) magnetic hydrogel nanocomposite could be an effective carrier for targeting drug delivery systems of anti-cancer drugs due to its temperature sensitive properties.

• 대한한방종양학회지
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• 제4권1호
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• pp.71-87
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• 1998

Even though appropriate immune response is necessary for the survival of the individual, excessive or insufficient immune Response might cause autoimmune or allergic disease. So the immune response must be controlled to the degree that is beneficial for the well being of the individual. This study was undertaken to know the effects of Gunleetang Gagambang on the immune system of the mouse. Gunleetang Gagambang has been used for cure of tumor as a traditional medicine without any experimental evidence to support the rational basis for its clinical use. This study was carried out to evaluate the possible therapeutic or antitumoral effects of Gunleetang Gagambang extract against tumor, and to carry out some mechanisms responsible for its effect. Some kinds of tumor were induced by the typical application of 3-methylcholanthrene(MCA) or by the implantation(s.c) of malignant tumor cells such as leukemia cells(3LL cells) or sarcoma cells(S180 cells). Treatment of the Gunleetang Gagambang on water-extract(dailly 1mg/mouse, i. p.) was continued for 7 days prior to tumor induction and after that the treatment was lasted for 20 days. Against squamous cell carcinoma induced by MCA, Gunleetang Gagambang decreased not only the frequency of tumor production but also the number and the weight of tumors per tumor bearing mice(TBM). Gunleetang Gagambang on also significantly suppressed the development of 3LL cell and S180 cell-implanted tumors in occurrence-frequency and their size. and some developed tumors were regressed by the continuous treatment of Gunleetang Gagambang extract into TBM. In vitro, treatment of Gunleetang Gagambang extract had no effect on the growth of some kinds of cell line such as FsaII, A431 strain but significantly inhibited the proliferation of 3LL, S180 cells and augmented the DNA synthesis of mitogen-activated lymphocytes. Gunleetang Gagambang also stimulated the migrative ability of leukocyte, the MIF and IL-2 production of T lymphocytes, but not IL 6 production of B cells. Gunleetang Gagambang administration to mice enhanced NK cells activities. These results demonstrated that Gunleetang Gagambang extract exhibited a significant prophylactic benefits against tumors and its antitumor activity was manifested depending on the type of tumor cells. And these results also suggested that effect of Gunleetang Gagambang might be chiefly due to nonspecitie enhancement of NK cell activities and cell-mediated immune responses.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.8.1-8.1
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• 2011

Nanocrystalline titanium dioxide ($TiO_2$) materials have been widely used as an electron collector in DSSC. This is required to have an extremely high porosity and surface area such that the dye can be sufficiently adsorbed and be electronically interconnected, resulting in the generation of a high photocurrent within cells. In particular, their geometrical structures and crystalline phase have been extensively investigated as important issues in improving its photovoltaic efficiency. In this study, we present a new strategy to fabricate a photoelectrode having a periodic structured $TiO_2$ film templated from 1D or 3D polystyrene (PS) microspheres array. Monodisperse PS spheres of various radiuses were used for colloidal array on FTO glasses and two types of photoelectrode structures with different $TiO_2$ materials were investigated respectively. One is the igloo-shaped electrode prepared by $TiO_2$ deposition by RF-sputtering onto 2D microsphere-templated substrates. At the interface between the film and substrate, there are voids formed by the decomposition of PS microspheres during the calcination step. These holes might be expected to play the predominant roles as scattering spherical voids to promote a light harvesting effect, a spacious structure for electrolytes with higher viscosity and effective paths for electron transfer. Additionally the nanocrystalline $TiO_2$ phase prepared by the RF-sputtering method was previously reported to improve the electron drift mobility within $TiO_2$ electrodes. This yields solar cells with a cell efficiency of 2.45% or more at AM 1.5 illumination, which is a very remarkable result, considering its $TiO_2$ electrode thickness (<2 ${\mu}m$). This study can be expanded to obtain higher cell efficiency by higher dye loading through the increase of surface area or multi-layered stacking. The other is the inverse opal photonic crystal electrode prepared by titania particles infusion within 3D colloidal arrays. To obtain the enlargement of ordered area and high quality of crystallinity, the synthesis of titania particles coated with a organic thin layer were applied instead of sol-gel process using the $TiO_2$ precursors. They were dispersed so well in most solvents without aggregates and infused successfully within colloidal array structures. This ordered mesoporous structure provides the large surface area leading to the enough adsorption of dye molecules and have an light harvesting effect due to the photonic band gap properties (back-and-forth reflection effects within structures). A major advantage of this colloidal array template method is that the pore size and its distribution within $TiO_2$ photoelectrodes are determined by those of latex beads, which can be controlled easily. These materials may have promising potentials for future applications of membrane, sensor and so on as well as solar cells.

• 한국결정성장학회지
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• 제23권1호
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• pp.31-36
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• 2013

친수성과 소수성을 동시에 갖는 아세틸화 셀룰로스 에테르(ACE)를 합성하여 유기용매 용해도 및 거동 평가와 물에 대한 젖음성을 평가하였다. 친수성 고분자인 셀룰로스 에테르에 에스테르화 반응을 통해 아세틸기를 치환시켰으며, FT-IR 분석결과 수산화기의 감소와 카르복실산의 증가를 통해 아세틸화 반응을 확인하였다. 열분해 거동 분석결과 $800^{\circ}C$까지 셀룰로스와 셀룰로스 에테르와 유사한 분해거동을 보여 셀룰로스 주사슬의 구조변화 없이 치환 반응이 일어난 것을 확인하였다. 18.5~26.4의 solubility parameter의 값을 예상할 수 있는 ACE는 유기용매의 solubility parameter 값에 의해 탁도와 점도가 결정되었다. 합성한 ACE의 접촉각은 셀룰로스 에테르 보다 높은 값을 보였으나 시간에 따른 접촉각 변화는 유사한 경향을 보였다. 이는 치환된 아세틸기에 의한 소수성, 무수 글루코스 단위체 내의 반응하지 않고 잔존하는 수산화기에 의해 친수성을 동시에 가지는 것을 알 수 있었다.

• 한국환경성돌연변이발암원학회지
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• 제25권2호
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• pp.60-65
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• 2005

The human solute carrier, SLC41Al, is a $Mg^{2}+$ transporter that is regulated by extracellular magnesium. Although intracellular magnesium plays a fundamental role in cellular metabolism, little is known about how $Mg^{2}+$ is taken up and controlled by cells. Magnesium plays a fundamental role in cellular metabolism so that its control within the body is critical. Magnesium homeostasis is principally a balance between intestinal absorption of dietary magnesium and renal excretion of urinary magnesium. The kidney, mainly the distal convoluted tubule, controls magnesium reabsorption. Although renal reabsorption is under the influence of many hormones, selective regulation of magnesium transport is due to intrinsic control involving transcriptional processes and synthesis of transport proteins. Using microarray analysis, identification of the genetic elements involved with this transcriptional control has been begun. SLC41A1(GenBank Accession No. AJ514402), comprises 10 putative transmembrane domains, two of which are highly homologous to the integral membrane part of the prokaryote transports $Mg^{2}+$ and other divalent cations $Sr^2+,\;Zn^2+,\;Cu^2+,\;Fe^2+,\;Co^2+,\;Ba^2+,\;and\;Cd^2+,\;but\;not\;Ca^2+,\;Mn^2+,\;and\;Ni^2+.$ Transport of $Mg^{2}+$ by SLC41Al is rheogenic, voltage dependent, and not coupled to Na or Cl. Expressed SLC41Al transports a range of other divalent cations: $Mg^{2+},\;Sr^{2+},\;Zn^{2+},\;Cu^{2+},\;Fe^{2+},\;Co^{2+},\;Ba^{2+},\;and\;Cd^{2+}$. The divalent cations $Ca^{2+},\;Mn^{2+},\;and\;Ni^{2+}$and the trivalent ion $Gd^{3+}$ did not induce currents nor did they inhibit $Mg^{2+}$ transport. The nonselective cation $La^{3+}$ abolishes $Mg^{2+}$ uptake. Computer analysis of the SLC41Al protein structure reveals that it belongs to MgtE protein family & suggested that the human solute carrier, SLC41Al, might be a eukaryotic $Mg^{2+}$ transporter closely related $(60-70\%)$ protein encoded by SLC41A2 is a $Mg^{2}+$ transporter that might be involved in magnesium homeostasis in epithelial cells also transports a range of other divalent cations: $Ba^2,\;Ni^2,\;CO^2,\;Fe^2,\;or\;Mn^2,\;but\;not\;Ca^2,\;Zn^2,\;or\;Cu^{2+}$ that may have related functional properties.

• Korean Chemical Engineering Research
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• 제53권1호
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• pp.1-5
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• 2015

Lactic acid(젖산)는 가장 널리 사용되는 Hydroxy-carboxylic acid로서 일반적으로 식품, 화장품, 의약품 및 화학산업의 원료로 사용된다. 하지만 다양한 분야의 적용과 대량생산의 광범위한 잠재력에도 불구하고 원재료의 높은 가격으로 인하여 Lactic acid 생산의 주된 문제가 된다. Lactic acid는 발효 또는 화학적 합성에 의하여 얻어진다. 최근, 자연적으로 생산되는 Lactic acid의 시장 수요가 증가하여 미생물 발효 방법에 의한 Lactic acid 생산을 일반적으로 사용한다. 일반적으로 Lactic acid 생산의 원재료는 순수한 전분 또는 글루코오스를 이용한다. 이의 경제적인 원재료의 대안으로, 지구상에서 가장 풍부한 재생가능 자원인 바이오매스를 가수분해물로 전환하여 이용한다. 본 연구에서는 Lactobacillus rhamnosus ATCC 10863을 이용하여 전처리 된 가수분해물로부터 발효 방법에 의해 L(+)-Lactic acid를 생산하였다. 전처리 된 가수분해물은 암모니아 침출 공정(AP) 후 효소 당화에 의하여 얻었다. 효과적으로 Lactic acid 생산 수율과 전환율을 높이기 위하여 순수 글루코오스 조건에서 배지, 온도, 글루코오스 농도를 조절하여 수행하였다. 발효 최적조건에서 순수 글루코오스와 가수분해물의 Lactic acid 생산을 비교하였다.

• Korean Chemical Engineering Research
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• 제54권6호
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• pp.786-791
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• 2016

친환경 환원제인 글루코스를 사용하여 액상 반응으로 그래핀 산화물을 환원시킨 후 에어로졸 분무건조 공정을 통하여 구형의 그래핀 볼(Graphene Ball, GB)을 제조하였다. 제조된 입자는 FE-SEM 분석을 통하여 구형임을 관찰하였고, XRD 분석으로 구형 입자들의 결정형이 그래핀임을 확인하였다. GB의 구형도는 온도, 글루코스의 양, 암모니아수($NH_4OH$)의 주입에 따라 조절할 수 있었다. 제조된 GB 중, 암모니아수 주입 하에 온도가 높은 조건에서 제조된 GB가 높은 구형도를 보였다. 암모니아수 주입하에 진행된 액상반응에 주입된 글루코스의 양이 증가할수록 구형도가 높은 GB가 생성되었다. 가장 높은 구형도를 가지는 GB의 구형도는 1.1이었다. 상대적으로 높은 구형도를 가지는 GB가 낮은 구형도를 가지는 GB보다 응집성이 감소됨을 확인할 수 있었다. 추가적으로 GB의 전기화학 분석 결과를 통해 GB가 커패시터의 전극 재료로서의 가능성을 보여주었다.

• Toxicological Research
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• 제21권4호
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• pp.347-353
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• 2005

Eukaryotic initiation factor 4E (elF4E) is a key element for cap-dependent protein translation controlled by affinity between elF4E and 4E-binding protein 1 (4E-BP1). Rapamycin can also affect protein translation by regulating 4E-BP1 phosphorylation. Tobacco-specific nitrosamine, 4(N-methyl-N-nitrosamino )-1-(3-pyridyl)-1-butanone (NNK) is a strong lung carcinogen, but its precise lung cancer induction mechanism remains unknown. Relative roles of cap-dependent and -independent protein translation in terms of NNK-induced lung carcinogenesis were elucidated using normal human bronchial epithelial cells. NNK concentrations applied in this study did not decrease cell viability. Addition of NNK restored rapamycin-induced decrease of protein synthesis and rapamycin-induced phosphorylation of 4E-BP1, and increased expression levels of mTOR, ERK1/2, p70S6K, and Raf-1 in a concentration-dependent manner. NNK also caused perturbation of normal cell cycle progression. Taken together, NNK might cause toxicity through the combination of restoration of 4E-BP1 phosphorylation and increase of elF4E as well as mTOR protein expression, interruption of Raf1/ERK as well as the cyclin G-associated p53 network. Our data could be applied towards elucidation of the molecular basis for lung cancer treatment.

• 공업화학
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• 제29권1호
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• pp.62-66
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• 2018

Styrenated phenol alkoxylate (SP-A)는 일반적으로 균일계 염기 촉매 하에서 styrenated phenol (SP)과 ethylene oxide (EO)로부터 제조되어진다. 그러나, 취급이 용이하지 않은 EO를 사용하려면 고압반응장치를 이용한 반응공정 제어가 필요하다. 또한, 균일계 염기 촉매를 사용하면 반응종결 후에 잔존하는 염기를 제거하기 위한 중화공정이 필요하고, 촉매와 생성물의 분리가 어렵다는 문제점이 있다. 따라서, 본 연구에서는 균일계 염기 촉매를 사용하지 않고 불균일계염기 촉매를 사용하여 SP와 ethylene carbonate (EC)의 반응으로부터 제조된 SP-A에 대하여 보고하고자 한다. SP-A의 제조에 사용된 불균일계 염기 촉매는 KOH를 $La_2O_3$에 담지시킨 후, 소성하여 얻었다. 또한, EO 대신 EC를 사용함으로써 고압반응이 아닌 상압반응 조건에서 SP-A제조가 가능하였다. 합성된 SP-A의 평균 분자량 크기는 반응조건에 따라서 매우 다양하게 나타났다. $KOH/La_2O_3$촉매 하에서 제조된 SP-A의 평균 분자량 크기는 반응온도, 촉매의 첨가량 및 EC의 첨가량을 조절함으로써 임의로 조절이 가능하였다.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2342-2348
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• 2014

Poly(lactic-co-glycolic acid) (PLGA) were grafted to both ends of Pluronic$^{(R)}$ F68 ($(EO)_{75}(PO)_{30}(EO)_{75}$) triblock copolymer to produce poly{(lactic acid)$_m$-co-(glycolic acid)$_n$}-b-poly(ethylene oxide)$_{75}$-b-poly(propylene oxide)$_{30}$-b-poly(ethylene oxide)$_{75}$-b-poly{(lactic acid)$_m$-co-(glycolic acid)$_n$} (PLGA-F68-PLGA) pentablock copolymers. Molecular weights of PLGA blocks were controlled and five kinds of pentablock copolymers with different PLGA block lengths were synthesized using in-situ ring-opening polymerization of D,L-lactide and glycolide with tin(II) 2-ethylhexanoate ($Sn(Oct)_2$) catalyst. PLGA-F68-PLGA pentablock copolymers were characterized by $^1H$- and $^{13}C$-NMR, GPC, and TGA. The numbers (2m, 2n) of repeating units for lactic acid and glycolic acid inside PLGA segments were obtained as (48, 17), (90, 23), (125, 40), (180, 59), and (246, 64), with $^1H$-NMR measurement. From NMR data, the resultant molecular weights were determined in the range of 12,700-29,700, which were similar to those obtained from GPC. Polydispersity index was increased in the range of 1.32-1.91 as the content of PLGA blocks increased. TG and DTG thermograms showed discrete degradation traces for PLGA and F68 blocks, which indicate the weight fractions of PLGA blocks in pentablock copolymers can be calculated by TG profile and it is possible to remove PLGA block selectively. Hydrodynamic radius and radius of gyration of pentablock copolymer micelle were obtained in the range of 46-68 nm and 31-49 nm, respectively, in very dilute (i.e. 0.005 wt %) aqueous solution of THF:$H_2O$ = 10:90 by volume at $25^{\circ}C$.