• Membrane Journal
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• v.32 no.2
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• pp.150-162
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• 2022

In the field of water treatment and pharmaceutical bio an alumina hollow fiber membrane used for mixture separation. However, due to the lack of strengths it is very brittle to handle and apply. Therefore, it is necessary to study and improve the bending strength of the membrane to 100 MPa or more. In this study, as the mixing ratio of the nano-particles increased to 0, 1, 3, and 5 wt%, the viscosity of the fluid mixture increased. The pore structure of the hollow membrane produced by interrupting the diffusion exchange rate of the solvent and non-solvent during the spinning process suppresses the formation of the finger-like structure and gradually increases the ratio of the sponge-like structure to improve the membrane mechanical strength to more than 100 MPa. As a result, an interparticle space was ensured to improve the porosity of the sponge-like structure with high permeability, and it showed excellent N2 permeability of about 100000 GPU and high water permeability of 3000 L/m² h. Therefore, it can be concluded, that the addition of γ-Al₂O₃ nanoparticles as sintering aid is an important method to enhance the mechanical strength of the α-alumina hollow fiber membrane to maintain high permeability.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1800-1808
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• 2013

Dual-responsive amphiphilic block copolymers were synthesized by combining enzymatic ring-opening polymerization (eROP) of ${\varepsilon}$-caprolactone (CL) and ATRP of N,N-dimethylamino-2-ethyl methacrylate (DMAEMA). The obtained block copolymers were characterized by gel permeation chromatography (GPC), $^1H$ NMR and FTIR-IR. The critical micelle concentration (CMC) of copolymer was determined by fluorescence spectra, it can be found that with hydrophilic block (PDMAEMA) increasing, CMC value of the polymer sample increased accordingly, and the CMC value was 0.012 mg/mL, 0.025 mg/mL and 0.037 mg/mL for $PCL_{50}$-b-$PDMAEMA_{68}$, $PCL_{50}$-b-$PDMAEMA_{89}$, $PCL_{50}$-b-$PDMAEMA_{112}$, $PCL_{50}$-b-$PDMAEMA_{89}$ was chosen as drug carrier to study in vitro release profile of anti-cancer drug (taxol). The temperature and pH dependence of the values of hydrodynamic diameter (Dh) of micelles, and self-assembly of the resulting block copolymers in water were evaluated by dynamic light scattering (DLS). The result showed that with the temperature increasing and pH decreasing, the Dh decreased. Drug-loaded nanoparticles were fabricated using paclitaxel as model. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) had been explored to study the morphology of the hollow micelles and the nanoparticles, revealing well-dispersed spheres with the average diameters both around 80 nm. In vitro release kinetics of paclitaxel from the nanoparticles was also investigated in different conditions (pH and temperature, etc.), revealing that the drug release was triggered by temperature changes upon the lower critical solution temperature (LCST) at pH 7.4, and at $37^{\circ}C$ by an increase of pH.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.429-436
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• 2018

Targeted intracellular delivery of therapeutic agents is one of the great challenges for cancer treatment. Aptamers that bind to a variety of biological targets have emerged as new targeting moieties with high specificity for targeted cancer therapy. In this study, near-infrared (NIR) light-absorbing hollow gold nanocages (AuNCs) were synthesized and conjugated with AS1411 aptamer to achieve cancer-targeted photothermal therapy. AuNC functionalized with PEG and AS1411 (AS1411-PEG-AuNC) exhibited selective cellular uptake in breast cancer cells due to selective binding of AS1411 to nucleolin, a protein that is over-expressed in cancer cells over normal cells. As a result, AS1411-PEG-AuNC showed cancer-targeted photothermal activity. This study demonstrates that aptamer-conjugated AuNCs are effective tumor-targeting photothermal agents.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.847-853
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• 2008

Although combustion is essential in most energy generation processes, it is one of the major causes of air pollution. Circle fin exhaust pipes were designed to study the effect of cooling the recirculated exhaust gases (EGR) of Diesel engines on the chemical composition of the exhaust gases and the reduction in the percentages of pollutant emissions. The designs adopted in this study were exhaust pipes with solid and hollow fins around them direct surface force measurement in water using a nano size colloidal probe Technique The direct force measurement between colloidal surfaces has been an essential topic in both theories and applications of surface chemistry. As particle size is decreased from micron size down to true Carbon nano Colloid size (<10nm), surface forces are increasingly important. Nanoparticles at close proximity or high solids loading are expected to show a different behavior than what can be estimated from continuum and mean field theories. This paper use Water and CNC fluid at normal cooling system of EGR. Experimental result showed all good agreement at Re=$2.54{\times}10^{4}$.

• Membrane Journal
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• v.30 no.5
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• pp.293-306
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• 2020

Increasing harmful effects of climate change, such as its effect on water scarcity, has led to a focus on developing effective water purification methods to obtain pure water. Additionally, rising levels of water pollution is increasing levels of environmental degradation, calling for sources of water treatment to remove contaminants. To purify water, osmotic processes across a semipermeable membrane can take place, and recent studies are showing that incorporating nanoparticles, including carbon quantum dots (CQDs), graphene carbon dots (GQDs), and graphene oxide quantum dots (GOQDs) are making thin film composite (TFC) membranes more effective by increasing water flux while maintaining similar levels of salt rejection, increasing the hydrophilicity of the membrane surface, showing bactericidal properties, exhibiting antifouling properties to prevent accumulation of bacteria or other microorganisms from reducing the effectiveness of the membrane, and more. In the review, the synthesis process, applications, functionality, properties, and the role of several types of quantum dots are discussed in the composite membrane for water purification.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.288-288
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• 2013

Lithium-ion battery (LIB) is one of the most important rechargeable battery and portable energy storage for the electric digital devices. In particular, study about the higher energy capacity and longer cycle life is intensively studied because of applications in mobile electronics and electric vehicles. Generally, the LIB's capacity can be improved by replacing anode materials with high capacitance. The graphite, common anode materials, has a good cyclability but shows limitations of capacity (~374 mAh/g). On the contrary, silicon (Si) and germanium(Ge), which is same group elements, are promising candidate for high-performance LIB electrodes because it has a higher theoretical specific capacity. (Si:4200 mAh/g, Ge:1600 mAh/g) However, it is well known that Si volume change by 400% upon full lithiation (lithium insertion into Si), which result in a mechanical pulverization and poor capacity retention during cycling. Therefore, variety of nanostructure group IV elements, including nanoparticles, nanowires, and hollow nanospheres, can be promising solution about the critical issues associated with the large volume change. However, the fundamental research about correlation between the composition and structure for LIB anode is not studied yet. Herein, we successfully synthesized various structure of nanowire such as Si-Ge, Ge-Carbon and Si-graphene core-shell types and analyzed the properties of LIB. Nanowires (NWs) were grown on stainless steel substrates using Au catalyst via VLS (Vapor Liquid Solid) mechanism. And, core-shell NWs were grown by VS (Vapor-Solid) process on the surface of NWs. In order to characterize it, we used FE-SEM, HR-TEM, and Raman spectroscopy. We measured battery property of various nanostructures for checking the capacity and cyclability by cell-tester.

• Nano
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• v.13 no.12
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• pp.1850144.1-1850144.13
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• 2018

A nano-$MoS_2$/montmorillonite K-10 (K10) composite was prepared and characterized. The composite contains two types of 2H-$MoS_2$ nanoparticles. One is the hollow spherical $MoS_2$ with a size range of 75 nm, and the other is the spherical nano cluster of $MoS_2$ with a size range of 30 nm. The two kinds of nano-$MoS_2$ were formed via assembly of numerous $MoS_2$ nano-platelets with a size of ~10 nm. A tribological comparison was then made among nano-$MoS_2$/K10, K10, nano-$MoS_2$ and a mechanical mixture of K10 and nano-$MoS_2$. K10 reduced the wear but slightly increased the friction. Nano-$MoS_2$ remarkably reduced both friction and wear. The mechanical mixture demonstrated better wear resistance than nano-$MoS_2$, indicating a synergistic anti-wear effect of nano-$MoS_2$ and K10. The synergistic effect was reinforced using nano-$MoS_2$/K10 instead of the mechanical mixture. A part of the $MoS_2$ in the contact region always lubricated the friction pair, and the rest formed a tribofilm. K10 segregated the friction pair to alleviate the ablation wear but magnified the abrasive wear. S-$MoS_2$ protects K10 and they together function as both a lubricant and an isolating agent to reduce the ablation and abrasive wear.

• BMB Reports
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• v.55 no.4
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• pp.175-180
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• 2022

Peptides are gaining substantial attention as therapeutics for human diseases. However, they have limitations such as low bioavailability and poor pharmacokinetics. Periostin, a matricellular protein, can stimulate the repair of ischemic tissues by promoting angiogenesis. We have previously reported that a novel angiogenic peptide (amino acids 142-151) is responsible for the pro-angiogenic activity of periostin. To improve the in vivo delivery efficiency of periostin peptide (PP), we used proteins self-assembled into a hollow cage-like structure as a drug delivery nanoplatform in the present study. The periostin peptide was genetically inserted into lumazine synthase (isolated from Aquifex aeolicus) consisting of 60 identical subunits with an icosahedral capsid architecture. The periostin peptide-bearing lumazine synthase protein cage nanoparticle with 60 periostin peptides multivalently displayed was expressed in Escherichia coli and purified to homogeneity. Next, we examined angiogenic activities of this periostin peptide-bearing lumazine synthase protein cage nanoparticle. AaLS-periostin peptide (AaLS-PP), but not AaLS, promoted migration, proliferation, and tube formation of human endothelial colony-forming cells in vitro. Intramuscular injection of PP and AaLS-PP increased blood perfusion and attenuated severe limb loss in the ischemic hindlimb. However, AaLS did not increase blood perfusion or alleviate tissue necrosis. Moreover, in vivo administration of AaLS-PP, but not AaLS, stimulated angiogenesis in the ischemic hindlimb. These results suggest that AaLS is a highly useful nanoplatform for delivering pro-angiogenic peptides such as PP.