Biography:

In the past Kun Han has collaborated on articles with Bong Gyu Yu and Minjie Li. One of their most recent publications is Development of a local antibiotic delivery system using fibrin glue. Which was published in journal Journal of Controlled Release.

More information about Kun Han research including statistics on their citations can be found on their Copernicus Academic profile page.

Kun Han's Articles: (16)

Development of a local antibiotic delivery system using fibrin glue

AbstractFibrin glue (FG) has been successfully used in a wide range of surgical fields such as skin graft fixation, nerve repair, cartilage reattachment and microvascular anastomoses. The sustained release of antibiotics from FG for a longer period is desirable to avoid bacterial infection after application. Ampicillin sodium (AMP-Na) was selected as a model antibiotic and incorporated into FG. The incorporation of AMP-Na was attempted in two different ways. One was incorporation of AMP-Na in a dispersed state with the modification of the preparation method of FG. The other was incorporation of bovine serum albumin microspheres (BSA-MS) containing AMP-Na. The in vitro release of AMP-Na from various FGs and BSA MS was examined. The modifications of FG were found not to be appropriate methods to achieve sustained release of AMP-Na. The incorporation of crosslinked BSA-MS containing AMP-Na into FG was found to reduce the initial rapid release of AMP-Na and retarded release of AMP-Na.

Easy preparation and characterization of highly fluorescent polymer composite microspheres from aqueous CdTe nanocrystals

AbstractFluorescent microspheres were easily fabricated from aqueous CdTe nanocrystals (NCs). The NCs, which had negative charges on the surface, were first extracted to chloroform by cationic surfactant octadecyl-p-vinyl-benzyldimethylammonium chloride (OVDAC) and then swollen into performed polystyrene (PS) microspheres. Through this method, strong photoluminescence (PL) of aqueous NCs was inherited in the resultant composite microspheres. Moreover, the NCs were firmly stabilized in the microspheres, withstanding not only polar solvents but also nonpolar solvents. UV–vis spectrum, PL spectrum, TEM, and confocal fluorescence microscopy were used to characterize the product.

Two-dimensional chemically tunable patterns with cellular structures fabricated via thermal pressing method

AbstractA novel and versatile soft lithography method, i.e. thermal pressing method has been established to create colloid arrays by using multilevel inks. Patterned poly(dimethylsiloxane) stamp containing silicone dioxide microparticles was pressed into a polycaprolactone (PCL) film at the temperature around the Tm of PCL. Subsequent removal of the colloids left cavity arrays. By initially incorporating chitosan, albumin or CdTe quantum dots into the silicone dioxide microparticles, removal of the ordered SiO2 microspheres would then release these substances which were stably embedded into the PCL matrices or suspended in the interiors of the cellular structures. By coating the SiO2 microspheres with multilayers previously, thin covers on the cellular structures could be obtained after removal of the templates.

Controllable synthesis of submicrometer-sized copper crystallites with different morphologies

AbstractPure submicrometer-sized copper crystallites with hexagonal, star-shaped and snowflake-shaped structures have been successfully synthesized via solvothermal treatment of CuSO4 ∙ 5H2O in ethylenediamine (EDA) at 190 °C for 12–18 h. X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) were employed to characterize the crystalline structure, size and morphology of the as-synthesized copper crystallites. It is found that reaction temperature, reaction time and reaction solvents all play important roles in the composition and morphology of the products. The possible reaction mechanism was discussed by Fourier transform infrared spectroscopy (FT-IR). Here, ethylenediamine can be used as a reducing agent as well as a coordination ligand.

Preparation and evaluation of poly(l-lactic acid) microspheres containing rhEGF for chronic gastric ulcer healing

AbstractBiodegradable microspheres containing recombinant human epidermal growth factor (rhEGF) were prepared using poly(l-lactic acid) by a solvent evaporation method based on multiple w/o/w emulsion. Encapsulation efficiency and initial release were influenced by the amount of polymer, inner water phase volume and osmotic pressure difference between inner water phase and outer water phase. The effect of osmotic pressure difference between inner water phase and outer water phase in w/o/w emulsion on particle size, porosity and in vitro release of rhEGF from microspheres were also studied. Microspheres prepared with the optimized osmotic pressure, polymer amount and inner water volume produced 21% initial release on the first day with 92% encapsulation efficiency. The blood concentration of rhEGF was maintained at constant levels for 9–11 days after a single subcutaneous (s.c.) administration of rhEGF microspheres. The gastric ulcer healing effect of a single s.c. administration of rhEGF microspheres was increased 1.44-fold compared with twice a day s.c. administration of rhEGF saline solution after 11 days. The enhanced curative ratio of rhEGF loaded microspheres may be due to the optimized osmotic pressure, high encapsulation efficiency and sustained release pattern.

Enhanced luminescence of GdTaO4:Eu3+ thin-film phosphors by K doping

AbstractThe effect of K+ ions on GdTaO4:Eu3+ thin-film phosphors was investigated in order to improve their luminescent properties. The GdTaO4:Eu0.1, Kx thin films were synthesized by sol–gel process, and characterized through measuring their microstructure and luminescence. The results indicated that photoluminescence (PL) intensity of GdTaO4:Eu3+ film was improved remarkably by K doping. There were two maxima in the curve of PL intensity against K+ dopant concentration, where one was improved up to 2.1 times at x = 0.001 and the other was enhanced up to 2.7 times at x = 0.05. The first maximum was regarded as the alteration of the local environment surrounding the Eu3+ activator by incorporation of K+ ions, and the second maximum was due to the flux effect. Additionally, the luminescence increased with the increase of firing temperature from 800 °C to 1200 °C.

Optical properties of GdTaO4:Eu3+ thick films prepared from a PVP-containing solution

AbstractTransparent GdTaO4:Eu3+ thick films were prepared from the inorganic salt and 2-methoxyethanol solution containing polyvinylpyrrolidone (PVP) via sol–gel technique. The critical thickness of the film, i.e. the maximum thickness achievable without crack formation via non-repetitive deposition, was 0.8 μm. The effect of PVP on the morphology, crystallization behavior and optical property of the GdTaO4:Eu3+ thick film was investigated. The results indicated that PVP could play an important role in the formation of transparent GdTaO4:Eu3+ thick films, suppressing the stress evolution, adjusting the sol viscosity, ameliorating the crystallinity, and strengthening the covalency of Eu–O bonds. The GdTaO4:Eu3+ thick films prepared with PVP exhibited a superior photoluminescence and X-ray exited luminescence, which implies that it will have promising applications in high-spatial-resolution X-ray imaging and flat panel display devices.

Antioxidative or prooxidative effect of 4-hydroxyquinoline derivatives on free-radical-initiated hemolysis of erythrocytes is due to its distributive status

Abstract7-Chloro-4-hydroxyquinoline (CQ) is an antitumor drug but its efficiency is not very satisfactory. This fact motivates us to study the relationship between the structure of 4-hydroxyquinoline with various substituent and its antioxidant effect against free-radical-initiated peroxidation: the hemolysis of human erythrocyte initiated thermally by water-soluble initiator, 2,2′-azobis (2-amidinopropane hydrochloride) (AAPH), acts as an experimental system. 7-Fluoro-4-hydroxyquinoline (FQ) and CQ can be synthesized by decarboxylation of 7-fluoro-4-hydroxyquinoline-3-carboxylic acid (FQCA) and 7-chloro-4-hydroxyquinoline-3-carboxylic acid (CQCA), respectively, and FQCA and CQCA are prepared by hydrolysis of ethyl 7-fluoro-4-hydroxyquinoline-3-carboxylate (FQCE) and ethyl 7-chloro-4-hydroxyquinoline-3-carboxylate (CQCE), respectively. The inhibitory concentration of 50% inhibition (IC50) of AAPH-induced hemolysis of the erythrocyte has been studied and found that all these chemicals dissolved in dimethyl sulfoxide (DMSO) can inhibit the free-radical-induced peroxidation. To clarify the relationship between the distributive status of the chemicals and their antioxidant effect, the chemical has been dissolved in the vesicle of dipalmitoyl phosphatidylcholine (DPPC) by sonication and suspended in the reaction system. It is found that FQCE, CQCE, FQCA and CQCA act as prooxidants either used alone or used in combination with α-tocopherol (TOH), demonstrating that FQCE, CQCE, FQCA and CQCA play a prooxidative role when they are packaged in the DPPC vesicle. This can be understood that the electron-attracting group, i.e. -COOC2H5, -COOH, at the ortho position to the hydroxy group of quinoline makes the phenoxy radical of quinoline derivatives active by attracting negative charge from the electron-deficient radical site. These unstable free radicals preserved in DPPC vesicle can initiate additional propagation of lipid peroxidation and cause hemolysis. However, FQ and CQ without electron-attracting group are antioxidants even in DPPC vesicle either used alone, or mixed with TOH. Moreover, the antioxidative activity of FQ is much better than CQ either used alone or in combination with TOH, indicating that FQ has the potential to replace CQ to be an antioxidant drug. Therefore, the antioxidant/prooxidant effect is not only correlated with the molecular structure but also the distributive status in the reaction system.

Polyethylene glycol-coated liposomes for oral delivery of recombinant human epidermal growth factor

AbstractThe present study was to investigate the feasibility of oral delivery of recombinant human epidermal growth factor (rhEGF). Polyethylene glycol (PEG)-coated liposomes containing rhEGF was prepared and evaluated for their stability and permeability in Caco-2 cells. In the animal study, we also determined plasma concentration and gastric ulcer healing effect after oral administration of rhEGF liposomes or the solution. Encapsulation of rhEGF into liposomes, suppressed the degradation in Caco-2 cell homogenate compared with the solution. The flux of rhEGF from dipalmitoylphosphatidylcholine (DPPC) liposome across Caco-2 cell monolayer from the apical to basolateral side was three times greater than that from phosphatidylcholine (PC) liposome or the solution. After oral administration of rhEGF liposomes or the solution in rats, the area under the concentration–time curve (AUC) of rhEGF increased 1.7- and 2.5-fold for PC and DPPC liposomes, respectively. The gastric ulcer healing effect was significantly increased in DPPC liposome compared with PC liposome and the solution. The enhanced curative ratio of rhEGF encapsulated into DPPC liposome may be due to the resistance to enzyme degradation, higher permeability and increased plasma AUC. Therefore, PEG-coated liposomes containing rhEGF could be used as an oral delivery formulation with enhanced encapsulation efficiency.

Nanoassembly of photoluminescent films containing rare earth complex nanoparticles on planar and microspherical supports

AbstractIn this paper, we describe the fabrication of photoluminescent films containing rare earth complex nanoparticles on both planar and spherical supports by using the layer-by-layer (LBL) self-assembly technique. The rare earth complex nanoparticles are synthesized in aqueous solution, with trivalent europium as the metal center ion, dibenzoylmethane (DBM) as the ligand and poly(ethylenimine) (PEI) as the stabilizing agent. The particle size is about 2 nm as revealed by transmission electron microscopy (TEM) images. During the formation of Eu(DBM)3 nanoparticles, PEI stabilize the nanoparticles and confer a well-defined positive surface, thus preventing the nanoparticles from aggregation and affording stable dispersion. These nanoparticles can be assembled to form ultrathin films by alternate deposition with poly(sodium 4-styrene sulfonate) (PSS) on planar supports. The resulting films show the same UV and fluorescence characteristics as the corresponding aqueous nanoparticle dispersion, which indicates that the deposition process is successful. In addition, atomic force microscopy (AFM) and TEM have been used to characterize the surface morphology of these films. Aggregations in the size range of 30–70 nm are found in the composite films. A strong and narrow emission peak at 612 nm can be found in the photoluminescence (PL) spectra of the LBL films, which is the characteristic emission of Eu3+. We have also extended the substrate of LBL assembly to microspherical surface, and obtained composite fluorescent shells on silica microspheres.

Short communicationHighly sensitive, label-free colorimetric assay of trypsin using silver nanoparticles

Highlights•Rapid and sensitive detection of trypsin using silver nanoparticles is achieved.•The peptide is designed as the stabilizer of AgNPs and the substrate of trypsin.•Determination of trypsin in human serum and urine samples is studied.•The sensing strategy provides a promising approach for clinical applications.

Strong enhancement of methylene blue removal from binary wastewater by in-situ ferrite process

AbstractDye wastewater containing heavy metal ions is a common industrial effluent with complex physicochemical properties. The treatment of metal–dye binary wastewater is difficult. In this work, a novel in-situ ferrite process (IFP) was applied to treat Methylene Blue (MB)–Cu(II) binary wastewater, and the operational parameters were optimized for MB removal. Results showed that the optimum operating conditions were OH/M of 1.72, Cu2 +/Fe2 + ratio of 1/2.5, reaction time of 90 min, aeration intensity of 320 mL/min, and reaction temperature of 40°C. Moreover, the presence of Ca2 + and Mg2 + moderately influenced the MB removal. Physical characterization results indicated that the precipitates yielded in IFP presented high surface area (232.50 m2/g) and a multi-porous structure. Based on the Langmuir model, the maximum adsorption capacity toward MB was 347.82 mg/g for the precipitates produced in IFP, which outperformed most other adsorbents. Furthermore, IFP rapidly sequestered MB with removal efficiency 5 to 10 times greater than that by general ferrite adsorption, which suggested a strong enhancement of MB removal by IFP. The MB removal process by IFP showed two different high removal stages, each with a corresponding removal mechanism. In the first brief stage (< 5 min), the initial high MB removal (~ 95%) was achieved by predominantly electrostatic interactions. Then the sweep effect and encapsulation were dominant in the second longer stage.

Korea red ginseng water extract increases nitric oxide concentrations in exhaled breath

AbstractPanax ginseng is well known to enhance the release of nitric oxide (NO) from endothelial cells of the rat aorta and to reduce blood pressure in animals. In this study, we investigated the effects of water extract of Korea red ginseng (KRG) on NO concentration levels in the exhaled breath, blood pressure, and heart rate of human volunteers. We also are interested in whether NO levels in exhaled breath are increased by KRG extract, and correlated with blood pressure and heart rate. Twelve healthy, non-smoking male volunteers were recruited for this study. A single administration of KRG water extract (500 mg/50 kg) increased NO levels in exhaled breath, and concomitantly decreased mean blood pressure and heart rate. The correlation value between NO levels and heart rate (r = 0.94), and the correlation value between NO levels and heart rate (r = 0.84) are significant (P < 0.01). Linear regression analysis shows the clear conversed correlation between NO levels and blood pressure as well as heart rate. Therefore, present data suggest that KRG may be useful for the treatment of hypertension and pulmonary vascular obstruction.

Hydrological Monitoring System Design and Implementation Based on IOT

AbstractIn this article, an embedded system development platform based on GSM communication is proposed. Through its application in hydrology monitoring management, the author makes discussion about communication reliability and lightning protection, suggests detail solutions, and also analyzes design and realization of upper computer software. Finally, communication program is given. Hydrology monitoring system from wireless communication network is a typical practical application of embedded system, which has realized intelligence, modernization, high-efficiency and networking of hydrology monitoring management.

ArticleRACK1 Promotes Autophagy by Enhancing the Atg14L-Beclin 1-Vps34-Vps15 Complex Formation upon Phosphorylation by AMPK

Highlights•Hepatocyte-specific RACK1 deficiency leads to lipid accumulation in the liver•RACK1 deficiency results in defective autophagy onset•RACK1 participates in the formation of autophagosome biogenesis complex•RACK1 promotes autophagy upon its phosphorylation by AMPK

High-throughput fabrication of 3D N-doped graphenic framework coupled with Fe3[email protected] graphite carbon for ultrastable potassium ion storage

AbstractGraphenic materials are deemed to be a promising anode material for potassium-ion battery (KIBs) due to its exceptional electronic conductivity, high surface area, light weight nature and chemical stability, while the high cost and low reversible capacity limit its practical application. Herein, we design a three-dimensional (3D) N-doped graphenic framework coupled with Fe3[email protected] graphite carbon core-shell structures (Fe3[email protected]) by a cheap and high-throughput chemical blowing strategy. This 3D graphenic framework spatially sustained by the graphitic struts has the capability to retain its integral structure during charge/discharge process. It should be emphasized that the Fe3C acts as an efficient catalyst in two stages: the formation of PGC wrapped around Fe3C during the synthetic process and the reversible formation/dissolution of solid electrolyte interface (SEI) film during cycling. More importantly, the PGC can confine the active Fe3C during K+ intercalation/deintercalation to avoid its pulverization and simultaneously increase the electronic conductivity. Thus, the Fe3[email protected] electrode exhibits an exceptional cycle performance of 10,000 cycles with high capacity retention of 155 mA h g−1 at 1000 mA g−1 and high initial Coulombic efficiency of 73% in KIBs.

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