• Korean Journal of Microbiology
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• v.28 no.1
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• pp.47-54
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• 1990

In order to investigate physiological characteristics of fusants by interspecific protoplast fusion of the genus Cellulomonas, protoplasts of Cellulomonas flavigena NCIB 12901 and Cellulomonas bibula NCIB 8142 were fused and cell wall regenerated. To give gene maker, C. bibula was treated with 500 ug/ml NTG for 1 hr and arginine requiring auxotrophic mutants were isolated. Protoplasts of the genus Cellulomonas were obtained by treatment with $600{\mu}{\textrm{g}}$/ml lysozyme, and 0.5M sorbitol was optimal for osmotic stabilizer on protoplast fromation. Protoplast fusion was enhanced by 40% PEG)M.W.6,000) containing 25 mM $CaCl_{2}$ at $30^{\circ}C$ for 30 min and fusion frequency between C. bibula and C. flavigena was $5\times 10^{-4}$. Processes of protoplast formation, cell wall regeneration and protoplast fusion were obsdrved by scanning electron microscope. By comparing enzyme activities of cellulase, exocellobiohydrolase, .betha.-glucosidase of the parent strains of Cellulomonas with those of thier mutants and fusants, fusants with increased enzyme activity were obtained. By the studies on nutritional requirement, antibiotic resistance, cellulolytic enzyme activities, type of peptidoglycan and motility of two mutants and fusants, fusants were proved to be recombinant of both mutant strains.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.5
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• pp.545-551
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• 2012

We investigated the diffusive transport of bupivacaine HCl through the microchannels of microfluidic drug delivery devices. In the biodegradable microfluidic drug delivery devices developed in this research, the drug release rate can be controlled by simply modulating the geometrical parameters of the microchannels, such as the length, number, and cross-sectional area of the microchannels, when the microchannels are used as paths for drug release. However, the hydrophobic nature of a biodegradable polymer, 85/15 poly(lactic-co-glycolic acid), hinders the infiltration of a release medium (phosphate-buffered saline) through the microchannels into the reservoir of a device that contains bupivacaine HCl, at the early stage of drug release. This can have an adverse effect on the early stage release of local analgesic compounds from the device. In this study, microfluidic channels were surface-treated with surfactants such as PEG600 and Tween80, and the effects of the surfactants on the release performance are presented and analyzed.

• KSBB Journal
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• v.16 no.3
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• pp.253-258
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• 2001

Recently, there were many studies not only to enhance drug delivery effect but to reduce side effect. Drug delivery system(DDS) is able to improve efficiency with decreasing side effect of drug dosage. Among these application fields, DDS is often used as the method of drug dosage into the epidermic skin. We investigated characters of transdermal therapeutic system(TTS) and the skin permeability of that with applying DDS. We investigated the permeation of xanthan gum containing drug in rat skin using borizontal membrane cell model. Permeation properties of materials were investigated for water-soluble drug with oxiniacic acid and also for lipophilic drug with clofibrate. The permeation rate of lipophilic drug was found to be faster than that of water-soluble drug in vitro. The rate differences of both water-soluble drug and lipophilic drug according to drug content were negligible. We used glycerin, PEG 600 and oleic acid as enhancers. These results showed that skin permeation rate of each drug across the composite was mainly dependent on the property of base and chemical property of drug etc.. Proper selection of the polymeric materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate. This result suggests a possible use of natural polymer base as a transdermal delivery system of antihyperlipoproteinemic agent.

• Fibers and Polymers
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• v.5 no.2
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• pp.95-104
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• 2004

A series of superabsorbents based on acrylic acid (AA), sodium acrylate, 2-acrylamido-2-methylpropane sulphonic acid, N,N'-methylene bis-acrylamide (MBA) were prepared by inverse suspension polymerization. These hydrogels were further crosslinked on the surface with polyethylene glycol-600 (PEG-600). The water absorbency or swelling behaviors for these xerogels in water and 0.9% saline solutions, both under free condition and under load were investigated. Absorption characteristics of these hydrogels were found to depend on nature and concentration of crosslinker in the system. It was also found that the saline absorption was significantly improved as the incorporation of AMPS in the polymer was increased. The surface crosslinking introduced in the polymers was found to improve the absorption under load characteristics without lowering the free water absorption capacities of the polymer to a considerable extent.

• Polymer(Korea)
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• v.25 no.6
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• pp.759-764
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• 2001

In order to obtain PEO with reduced crystallinity, novel PEO derivatives containing carbonate linkages in the main chain have been synthesized by the reaction of various molecular weight poly (ethylene glycol)s (PEGs) with dimethyl carbonate (DMC) in the presence of $H_2SO_4$ to yield methyl carbonate terminated PEGs, followed by condensation reaction under vacuum in the presence of titanium isopropoxide (TiP) catalyst. The number average molecular weight of PEGs used was in the range of 200 and 600 g/mol. The structure and compositions of the resulting polymers were characterized by $^1$H-NMR and $^{13}C-NMR$. Their thermal behavior and molecular weight were characterized by DSC/TGA and GPC, respectively.

• Membrane Journal
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• v.18 no.1
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• pp.94-102
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• 2008

For the treatment of the dye wastewater, a polyamide nano-composite membrane and reverse osmosis (RO) membranes were prepared using interfacial polymerization technique, in which piperazine, meta-phenylene diamine, and trimesoyl chloride were used as monomers, Their permselective properties were characterized with aqueous solutions of PEG 600, $Na_2SO_4$, and NaCl, and their performance was compared with that of Osmonics Co, They were found to be a typical nano-composite membrane and a low pressure RO membrane. Using them, a real dye wastewater supplied from the Kyungin Corporation, one of the domestic dye producer, was treated, studying the separation performances of the membranes, Also, during the wastewater treatment, cleaning in place (CIP) of the membranes was carried out regularly to recover the flux of the membranes. Three different chemical cleaners were employed for the CIP process and their performance were compared in this study.

• Membrane and Water Treatment
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• v.5 no.2
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• pp.109-122
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• 2014

Polyvinylidene fluoride (PVDF) hollow fiber membrane is widely used for water treatment. However, the weak mechanical strength of PVDF limits its application. To enhance its tensile strength, a double-layer composite hollow fiber membrane, with PVDF and polyetherimide as the external and inner layers, respectively, was successfully prepared through phase inversion technique. The effects of additive content, air gap distance, N,N-dimethyl-acetamide content in the inner core liquid, and the temperature of external coagulation bath on the membrane structure, permeation flux, rejection, tensile strength, and porosity were determined. Experimental results showed that the optimum preparation conditions for the double-layer composite hollow fiber membrane were as follows: PEG-400 and PEG-600, 5 wt%; air gap distance, 10 cm; inner core liquid and the external coagulation bath should be water; and temperature of the external coagulation bath, 40 C. A single layer PVDF hollow fiber membrane (without PEI layer) was also prepared under optimum conditions. The double-layer composite membrane remarkably improved the tensile strength compared with the single-layer PVDF hollow fiber membrane. The permeation flux, rejection, and porosity were also slightly enhanced. High-tensile strength hollow fiber PVDF ultrafiltration membrane can be fabricated using the proposed technique.

• Journal of Conservation Science
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• v.5 no.2 s.6
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• pp.51-56
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• 1996

This paper deals with the restoration of ancient wooden bridge foundation which excavated in Seta river Shiga Prefecture, Japan. Shiga Archeological Research started a marine archeological investigation of the bridge foundation in 1987. The bridge foundation stricture excavated and have since then recovered about a lots of woods and another materials. The bridge foundation structure constructed log, timbers and stones. The species of those waterlogged wood were identified as two types, hardwood and softwood. Hardwood(log : Cyclobalanopsis) was used for below foundation and softwood (timber' Chamaecyparis obtusa Endl. Cupreessaceae) was used for base structure. One of those timber sample dated by dendrochronology, we asked Dr. Misutani*. The softwood gave a felling date of 567 A.D. In result, the ancient Seta bridge foundation structure had constructed between Asuka and Nara period. We healed the news that ancient bridge foundation excavated at Woljyongyo site in Kyongju, Korea 1987. The bridge foundation Setakarahashi is similar in plane and structure to Woljyongyo structures. The Woljyongyo site report had be of value for reference. We had planning to restore those woods. Hardwood log was got serious damage. The water content varies from 400 to $600\%$. The other timbers water content varies about $200\%$. In the Shiga Center for Archaeological Operations and the Azuchi Castle Archaeological Museum, we set up the PEG impregnation tank. Those wooden objects treated by PEG method. PEG with a molecular weight of 4000. The treatment results may be considered satisfactory. The ancient wooden Seta bridge was reconstructed in Biwako Museum which established in Oct. 1996. We must take care of indoor exhibition environments. (*Nara National Cultual Properties Research Institute).

• Journal of Nutrition and Health
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• v.29 no.2
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• pp.153-158
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• 1996

Polyethylene glycols(PEGs)are hydrophilic molecules that have been used to characterize intestinal permeability via the paracellular pathway. Using a mixture of PEGs(400, 600 and 1000), containing oligomers in the molecular weight range 330 to 1122 D, the molecular weight permeability dependence in the jejunum of the rat small intestine was examined, employing an in situ recirculation perfusion technique. Individual oligomers were determined by HPLC with refractive detection. In the range studied, a distinct molecular weight cut-off was not apparent. Corrected for the length of jejunum used in the study, over the molecular weight range 330 to 1122D, the apparent permeability(Papp) of PEG ranged from 4.92$\pm$0.02$\times$10-5cm/sec(mean$\pm$SEM, n=5) to 0.28$\times$10-5cm/sec. Also, it was observed that the apparent permeability was inversely proportional to approximately MW2. The results in this study suggest that molecular weight is an important factor in determining the intestinal permeability.

• Korean Membrane Journal
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• v.1 no.1
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• pp.86-92
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• 1999

The nanofiltration (NF) membranes based on poly(vinyl alcohol) (PVA) and sodium alginate (SA) were prespared. Homogeneous PVA/SA blend membranes were prepared by casting a PVA/SA (95/5 in wi%) mixture solution on an acryl plate followed by drying at a room temperature and by cros-slinking with glutaraldehyde (GA) for 20 minutes PVA/SA blend composite membranes were also prepared by coating a PVA/SA (95/5 in wi%) mixture solution on microporous polysulfone(PSF) supports. The PVA/SA active layer of the composite membrane was crosslinked at room temperature by using an membranes were characterized with a scanning electron microscopy (SEM) a fourier transform infrared spectroscopy (FTIR) and permeation tests. The permeation properties of the composite membrane were as follows: 1.3{{{{ {m }^{2 } }}}}/{{{{ {m }^{2 } }}}}day of flux and >95% of rejection at 200 psi for a 1000 ppm PEG600 solution.