• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.115-122
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• 1983

The author surveyed 2,082 schoolchildren (Male: 1,078, Female: 1,004) from 7 to 12 years old in "N" primary school in kwang Ju City, and studied on 304 schoolchildren (Male: 176, Female: 128) having maxillary median diastema. The results were as follows: 1. The prevalence of maxillary median diastema was 14.6%, and it showed the greater rate at the boys than at the girls and the highest rate at 8 years old in the both sexes. 2. The maxillary median diastema showed decreasing tendency with ageing. 3. The frenum distance in children without local factors showed no change and the divergent degree of maxillary median diastema showed decreasing tendency after the eruption of maxillary lateral incisors. 4. The rate of maxillary median diastema associated with local factors was 37.8% and it showed increasing tendency with ageing. 5. The prevalence of median diastema according to etiology was as follows; rotated tooth; 12.2%, supernumerary teeth; 10.9%, abnormal frenum; 9.5%, peg lateralis; 7.2%, open bite; 2.6%, abnormal pattern of interseptal alveolar bone; 2.6%, missing lateral incisor; 0.7%, tooth size discrepancy; 0.3%.

• The Korean Journal of Food And Nutrition
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• v.13 no.5
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• pp.477-482
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• 2000

For the purpose of explaining the dewatering phenomena of potato slice soaked in concentrated solution three models were proposed. Earlier model cannot explain the dewatering phenomena of potato slice in concentrated solution because of limiting its condition which is necessary to build a model. Therefore other three models were suggested and a model based on Fick\`s second law of mass transport at infinite plate conditions and numerical analysis was test model for explaining dewatering phenomena of potato soaked in concentrated solution. Apparent diffusion coefficient of water could be readily estimated from model III, and it could explain adequately the difference of the dewatering phenomena of various soaking conditions.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.295-298
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• 2008

Creatine kinase (CK; E.C. 2.7.3.2) is an important enzyme that catalyzes the reversible transfer of a phosphoryl group from ATP to creatine in energy homeostasis. The brain-type cytosolic isoform of creatine kinase (BB-CK), which is found mainly in the brain and retina, is a key enzyme in brain energy metabolism, because high-energy phosphates are transfered through the creatine kinase/phosphocreatine shuttle system. The recombinant human BB-CK protein was overexpressed as a soluble form in Escherichia coli and crystallized at $22^{\circ}C$ using PEG 4000 as a precipitant. Native X-ray diffraction data were collected to $2.2{\AA}$ resolution using synchrotron radiation. The crystals belonged to the tetragonal space group $P4_32_12$, with cell parameters of a=b=97.963, $c=164.312{\AA},\;and\;{\alpha}={\beta}={\gamma}=90^{\circ}$. The asymmetric unit contained two molecules of CK, giving a crystal volume per protein mass $(V_m)$ of $1.80{\AA}^3\;Da^{-1}$ and a solvent content of 31.6%.

• 한국균학회소식:학술대회논문집
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• 2009.10a
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• pp.14-16
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• 2009

Poria cocos is an importantant medical macrofungus,the sclerotium of Poria cocos has specific value as the drug material. There are few papers about its breeding and spawn rejuvenation. In this project, the protoplasts of cultivated strain T and wild strain L were prepared and treated separately by ultraviolet and heating, then fused with the PEG6000. The tural fusants were selected and identified by the affinity and ISSR analysis. 71 incompatibility strains between parents and reg regenerations were obtained from 118 regenerations by the affinity analysis. Five incompatibility strains were amplified with different primers, the results were showed that they had specific bands of both parents in the profile amplified with 3 primers, which proved these 5 strains were fusants by means of molecular biology marker. On the other hand, 25 strain were selected from 168 protoplast regenerations of cultivated strain T for cultivation experiment. The fresh sclerotium weight of these protoplast regenerations were better than the original strain.significantil 3 strains (T-1, T-4, T-7) increased respectively 118%, 73% and 73% than original strain. This method could be the effective in the rejuvenation Poria cocos.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.74-77
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• 1999

The object of this study is to determine the effect of priming on the germination ability and seedling emergence of aged soybean seeds in lab and field conditions. Artificial or natural procedure for seed aging was applied in this study. One seed lot was artificially aged for 3 to 5 days at 42$^{\circ}C$ with high relative humidity (nearly RH 100%), and the other one was stored at room temperature for 17 months. Aged seeds were osmoconditioned in -1.1 MPa polyethylene glycol 8000 (PEG) solution for 3 days at $25^{\circ}C$ and air-dried. When Danyeobkong was aged for 4 days average germination was 61.5%, however, this improved to 98.5% after the priming treatment. Improvement of seed germination by priming the aged seed was consistent with large seed sized Jangyeobkong cultivar, indicating that the priming was effective in enhancing seed germinability regardless of seed size. Priming aged seeds also resulted in good stand establishment in the field trials. Germination of aged seeds of Danyeobkong without priming was 17.0%, whereas that of primed ones was 66.4%.

• Korean Journal of Microbiology
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• v.28 no.4
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• pp.311-317
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• 1990

Intraspecific and interspecific protoplast fusions in/between C. thermocellum and C. thermohydrosulfuricum were studied. Protoplast fusions were well induced in 30-40% PEG solution, however, their fusion frequencies were low level of 1.2*10$^{-7}$ for intraspecific fusion of C. thermocellum, $6.7*10^{-7}$ for C. thermohydrosulfuricum, and 4.2*10$^{-7}$ for interspecific fusion between above two Clostridia, respectively. Most fusants were unstable and segregated after 3 subcultures. Relatively stable intraspecific C. thermocellum fusant FTT17, intraspecific C. thermohydrosulfurecum fusant FSS22 and interspecific fusant FTS3, which were stable after several subcultures, were selected and properties of fusants were further investigated, Phenotypes of the fusants were similar with wild types mostly in cellular morphology, carbon source assimilation and enzyme activities. However they were differed in assimilation of pyruvic acid and sorbitol as carbon source. The DNA contents of fusants were slightly increased compared with wild types. Ethanol production by intraspecific and/or interspecific fusants was not increased, however, acetic acid production as byproduct was decreased or not detected, which indicates that industrial thermophilic anaerobes can be improved by means of protoplast fusion of two strains.

• Korean Journal of Microbiology
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• v.22 no.3
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• pp.175-181
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• 1984

In order to develope a protoplast fusion system for industrial coryneform bacteria, the optimum conditions for the formation and regeneration of progoplast were examined for Brevibacterium flavum and Corynebacterium glutamicum and the protoplast fusion was performed. For the formation of the protoplast of B. flavum and C. glutamicum, the optimum time for penicillin G. treatment to obtain protoplast was mid-exponential growth phase ($O.D_{580}=0.6-0.8,\;8.0{\times}10^7-1.0{\times}10^8cell/ml$). At the optimum conditions (0.3units/ml penicillin G and $400{\mu}g/ml$ lysoyme for treatement), frequencies of protoplast formation and protoplast regeneration were 99% and 25%, respectively. Protoplast regeneration frequency was highest under the optimum conditions for the protoplast formation. Addition of 25mM $Mg^{2+}\;and\;50mM\;Ca^{2+}$ to the regeneration medium further increased the regeneration frequencies. The protoplast fusion frequencies of B. flavum and C. glutamicum in intraspecies fusion were $1.0{\times}10^{-8}\;and\;7.8{\times}10^{-4}$, of the regenerated protoplast respectively, when 33% of PEG (polythylene glycol) 6,000 was used as the fusing agent.

• Mass Spectrometry Letters
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• v.7 no.3
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• pp.79-83
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• 2016

We prepared solid dispersion formulations of quercetin to enhance its solubility and dissolution rate. Various quercetin-loaded solid dispersion were tested with quercetin, poloxamer 407, and carrier such as hydroxypropyl methyl cellulose (HPMC), polyethylene glycol 8000 (PEG 8000), and polyvinylpyrrolidone K40 (PVP K40) using solvent evaporation and freeze drying methods in terms of both the aqueous solubility and the dissolution rates of quercetin. The solubility of quercetin as its solid dispersion formulations was markedly improved compared with that of quercetin powder. Especially, highest solubility of quercetin was observed when HPMC was used as a carrier. The cumulative dissolution of quercetin within 360 min from solid dispersion composed of quercetin, poloxamer 407, and HPMC was 8.8-fold higher than the dissolution of pure quercetin. The results of powder X-ray diffraction (XRD) and scanning electron microscope (SEM) indicated that quercetin transformed from a crystalline to an amorphous form through the solid dispersion formulation process. These results suggest that the solid dispersion formulation of quercetin with poloxamer 407 and HPMC could be a promising option for enhancing the solubility and dissolution rate of quercetin.

• Membrane and Water Treatment
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• v.6 no.3
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• pp.173-187
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• 2015

The goal of present work is the preparation of a novel positively charged nanofiltration (NF) membrane and its development for the cation removal of aqueous solutions. This NF membrane was fabricated by the surface modification of polysulfone (PSf) ultrafiltration support. The active top-layer was formed by interfacial cross-linking polymerization of poly(ethyleneimine) (PEI) with p-xylylene dichloride (XDC) and then quaternized with methyl iodide to form a perpetually positively charged layer. In order to improve the efficiency of nanofiltration membrane, the concentration of PEI, XDC and methyl iodide solutions, PEI coating and cross-linking time have been optimized. As a result, a high water flux and high $CaCl_2$ rejection (1,000 ppm) was obtained for the composite membrane with values of $18.29L/m^2.h$ and 93.62% at 4 bar and $25^{\circ}C$, respectively. The rejections of NF membrane for different salt solutions followed the order of $Na_2SO_4$ < $MgSO_4$ < NaCl < $CaCl_2$. Molecular weight of cut off (MWCO) was calculated via retaining of PEG solutions with different molecular weights that finally, it revealed the Stokes and hydrodynamic radius of 1.457 and 2.507 nm on the membrane selective layer, respectively. The most efficient positively charged nanofiltration membrane exhibited a $Ni^{2+}$ rejection of 96.26% for industrial wastewater from Shamse Hadaf Co. (Kashan, Iran).

• Membrane and Water Treatment
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• v.3 no.1
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• pp.35-49
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• 2012

In membrane processes, various agents are used to enhance, protect, and recover membrane performance. Applying these agents in membrane modification could potentially be considered as a simple method to improve membrane performance without additional process. Citric acid (CI) and sodium bisulfite (SB) are two chemicals that are widely used in membrane feed water pretreatment and cleaning processes. In this work, preadsorptions of CI and SB were developed as simple methods for polysulfone ultrafiltration membrane modification. It was found that hydrogen bonding and Van Der Waals attraction could be responsible for the adsorptions of CI and SB onto membranes, respectively. After modification with CI or SB, the membrane surfaces became more hydrophilic. Membrane permeability improved when modified by SB while decreased a little when modified by CI. The modified membranes had an increase in PEG and BSA rejections and better antifouling properties with higher flux recovery ratios during filtration of a complex pharmaceutical wastewater. Moreover, membrane chlorine tolerance was elevated after modification with either agent, as shown by the mechanical property measurements.