• Biotechnology and Bioprocess Engineering:BBE
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• v.1 no.1
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• pp.18-21
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• 1996

A continuous production of fructooligosaccharides from sucrose was investigated by fructosyltransferase immobilized on a high porous resin, Diaion HPA25. The optimum pH(5.5) and temperature(55$^{\circ}C$) of the enzyme for activity was unaltered by immobilization, and the immobilized enzyme became less sensitive to the pH change. The optimal operation conditions of the immobilized enzyme column for maximizing the productivity were as follows: 600g/L of sucrose feed concentration, flow rate of superficial space velocity 2.7h-1. When the enzyme column was run at 50$^{\circ}C$, about 8% loss of the initial activity of immobilized enzyme was observed after 30 days of continuous operation, during which high productivity of 1174g/L$.$h was achieved. The kinds of products obtained using the immobilized enzyme were almost the same as those using soluble enzymes or free cells.

• Transactions on Electrical and Electronic Materials
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• v.9 no.6
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• pp.231-236
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• 2008

B, P, and Cs ions were implanted with various parameters into silicon nitride layers prepared by LPCVD. In order to get the maximum impurity concentration at the silicon nitride surface, a high temperature oxide (HTO) buffer layers was deposited prior to the implantation. Alkali ion and pH sensing properties of the layers were investigated with an electrolyte-insulator-silicon (EIS) structure using high frequency capacitance-voltage (HF-CV) measurements. The ion sensing properties of implanted silicon nitrides were compared to those of as-deposited silicon nitride. Band Cs co-implanted silicon nitrides showed a pronounced difference in pH and alkali ion sensing properties compared to those of as-deposited silicon nitride. B or P implanted silicon nitrides in contrast showed similar ion sensitivities like those of as-deposited silicon nitride.

• Applied Biological Chemistry
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• v.37 no.5
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• pp.414-420
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• 1994

Birnessite, pyrolusite and hausmannite were synthesized and tested for the ability to oxidize Cr(III) to Cr(VI). These oxides differed in zero point of charge, surface area, and crystallinity. The kinetic study showed that Cr(III) oxidation on the Mn-oxide surface is a first-order reaction. The reaction rate was various for different oxide at different conditions. Generally the reaction by hausmannite, containing Mn(III), was faster than the others, and oxidation by pyrolusite was much slower. Solution pH and initial Cr(III) concentration had a significant effect on the reaction. Inhibited oxidation at higher pH and initial Cr(III) concentration could be due to the chance of Cr(III) precipitation or complexing on the oxide surface. Oxidations by birnessite and hausmannite were faster at lower pH, but pyrolusite exhibited increased oxidation capacity at higher pH in the range between 3.0 and 5.0. Reactions were also temperature sensitive. Although calculated activation energies for the oxidation reactions at pH 3.0 were higher than the general activation energy for diffusion, there is no experimental evidence to suggest which reaction is the rate limiting step.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.4
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• pp.449-457
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• 2012

The program/erase (P/E) cyclic endurances including bias temperature instability (BTI) behaviors of Metal-$Al_2O_3$-Nitride-Oxide-Semiconductor (MANOS) memories are investigated in comparison with those of Semiconductor-Oxide-Nitride-Oxide-Semiconductor (SONOS) memories. In terms of BTI behaviors, the SONOS power-law exponent n is ~0.3 independent of the P/E cycle and the temperature in the case of programmed cell, and 0.36~0.66 sensitive to the temperature in case of erased cell. Physical mechanisms are observed with thermally activated $h^*$ diffusion-induced Si/$SiO_2$ interface trap ($N_{IT}$) curing and Poole-Frenkel emission of holes trapped in border trap in the bottom oxide ($N_{OT}$). In terms of the BTI behavior in MANOS memory cells, the power-law exponent is n=0.4~0.9 in the programmed cell and n=0.65~1.2 in the erased cell, which means that the power law is strong function of the number of P/E cycles, not of the temperature. Related mechanism is can be explained by the competition between the cycle-induced degradation of P/E efficiency and the temperature-controlled $h^*$ diffusion followed by $N_{IT}$ passivation.

• Journal of Microbiology
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• v.33 no.3
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• pp.244-251
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• 1995

An extracellular protease of Salmonella schottmulleri was purified from culture filtrate by using 0-75% ammonium sulfate precipitation, DEAE Sepharose Fast Flow ion exchange chromatography, Ultrogel HA chromatography and Sephacryl S-200 HR molecular sieve chromatography. To measure enzyme activity, synthetic dipeptide substrate (CBZ-arg-arg-AFC) with low molecular weight was employed as substrate. The molecular weight of the purified enzyme was approximately 80 kDa when determined by gel filtration on Sephacryl S-200 HR and 73 kDa when estimated by SDS-PAGE. The isoelectric point was 5.45. The activity of the purified enzyme was inhibited by metal chelating agesnts such as EDTA and 1.10-phenanthroline. The divalent cations, such as Ca$\^$2+/, Zn$\^$2+/, Fe$\^$2+/, Mg$\^$2+/ enhanced its activity. These results suggested that it was a metalloprotease. It had a narrow pH optimum of 6.5-7.5 with a maximum at pH 7.0 and a temperature optimum of 40.deg.C. It was stable at least for 1 week at 40.deg.C and maintained its activity for 24 hours at 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium 50.deg.C, but it was rapidly inactivated at 65.deg.C. This protease was shown to be sensitive to sodium dodecyl sulfate (SDS) and was inactivated in a dose-dependent manner. However, it was resistant to Triton X-100 and the activity was enhanced to 32.3% with treatment of 0.025% Triton X-100.

• Journal of Life Science
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• v.14 no.4
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• pp.582-588
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• 2004

Eighty one bacterial strains of parathion degrading bacteria were isolated from soil samples that were contaminated with pesticide in Daejeon area. Among them, one bacterial strain was finally selected in media containing parathion as the sole source of carbon and energy, and this strain was identified as Pseudomonas rhodesiae H5 through physiological and biochemical tests, and analysis of its 16S rRNA sequence. Pseudomonas rhodesiae H5 was able to utilize various carbohydrates but did not utilize sorbose as sole carbon source. Pseudomonas rhodesiae H5 was resistance to ampicillin, spectinomycin, and mitomycin C but sensitive to kanamycin and chloramphenicol. And this strain showed high resistance up to several milligrams of heavy metals such as $BaCl_2$, LiCl, and $MnSO_4$. Optimal growth condition for temperature and pH of P. rhodesiae H5 was 3$0^{\circ}C$, and pH 7.0, respectively. It can be presumed that P. rhodesiae H5 hydrolyzed an organophosphate bond of parathion, forming p-nitrophenol, and then metabolized via ortho-ring cleavage mechanism.

• Journal of Sericultural and Entomological Science
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• v.31 no.2
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• pp.121-126
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• 1989

Two kinds of solution for the measurement of solubilities of Sericin are prepared as followings at temperature 90 deg. C. One has the total carbonate concentration as 0, 50, 100mg CO2/l prepared with non-carbonate distilled water, sodium hydrogen carbonate and 0.1N HCI and NaOH, the other has total hardness, that is, calcium hardness or magnesium hardness as 0, 20, 50, 100mg CaCO2/l respectively prepared with non-carbonate distilled water, calcium carbonate and magnesium oxide. Solubilities of Cocoon layer Sericin at above solution gives following results ; 1. pH shows little effect on the solubility of Sericin at the non-carbonate solution but at the carbonate solution pH shows a sensitive effect on the solubility of Sericin. These means that pH controls the concentration of H2CO3, HCO3-and CO32- which prevent and promote the solution of Sericin. 2. After the cocoon layer treatment at the solution, the initial pH of 4.0, 7.0, 9.0 of the solution changed to 6.0-6.5 at the lower total carbonate solution. However in the higher total carbonate solution pH did not changed very much. This may be explained by the buffer action of carbonate. 3. The effect of the hardness on the solubility of Sericin was not found in the non-carbonate solution with the standard hardness after treatment of cocoon layer.

• Journal of Microbiology
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• v.40 no.1
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• pp.20-25
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• 2002

An extracellular PHB depolymerase was purified from P. simplicissimum LAR13 cultural medium by Sepharose CL-6B chromatography. When the fungus was grown in a basal salt medium with poly(3-hydroxybutyrate) (PHB) as the sole carbon source, PHB depolymerase production reached maximum at its stationary phase. The mycelial growth rate was higher at 37$^{\circ}C$ than at 30$^{\circ}C$ and even higher than at 25$^{\circ}C$, However, the enzyme production was lower at 37$^{\circ}C$ than 30$^{\circ}C$ or 25$^{\circ}C$. The isolated enzyme is composed of a single polypeptide chain with a molecular mass of about 36 kDa as determined by SDS-PAGE. The optimum conditions for the enzyme activity are pH 5.0 and 45$^{\circ}C$. The enzyme was stable for 30 min at a temperature lower than 50$^{\circ}C$, and stable at pH higher than 2.0 but it was unstable at pH 1.0.1 mM Fe$\^$2+/ reduced the enzyme activity by 56% and the enzyme was inhibited almost completely by 4 mM Fe$\^$2+/ . The enzyme was partially inhibited by phenylmethylsulfonyl fluoride and was very sensitive to diazo-DL-norleucine methyl esters dithiothreitol and mercuric ion. However, N-p - tosyl - L - Iysinechloromethyl ketone, p -hydroxymercuricbenzoate and N- acetylimidazole had no influence upon its activity.

• Microbiology and Biotechnology Letters
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• v.17 no.1
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• pp.69-73
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• 1989

Cellular autolytic enzyme was isolated from the supernatant fluid of exponentially growing cuiture of Cl. butyricum ID-113. The autolysin was partially pruified by ammonium sulfate fractionation, chromatography on DEAE-Sephadex A-50 and gel filtration through Sephadex G-200. This autolytic enzyme lysed SDS-treated cell wall fractions of Cl. butyricum ID, but not whole cells at all. Its optimum pH and temperature were 5.0 and 37$^{\circ}C$, respectively. This enzyme was relatively stable at neutral pH, but sensitive to heat treatment. Enzyme activity was not influenced by the addition of various divalent cation, but inhibited by Cu$^{++}$.

• Applied Chemistry for Engineering
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• v.20 no.4
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• pp.370-374
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• 2009

A double-layer optical sensing membrane has been fabricated to measure the concentration of dissolved oxygen (DO) and pH value simultaneously. (tris(4,7-diphenyl-1,10-phenanthroline (Rudpp) ruthenium(II)) as a DO sensitive dye has been mixed in the methyl trimethoxy silane (MTMS) sol-gel solution and coated onto one well in a 24-well microtiter plate. On the DO-sensing layer the GA (3-glycidoxypropyl trimethoxy silane (GPTMS), 3-aminopropyl trimethoxy silane (APTMS)) sol-gel solution mixed with 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) has been coated and used to measure pH values. The double-layer sensing membrane was affected by ionic strength and temperature. The double-layer sensing membrane for DO and pH has been applied to online monitor in microorganism cultivation processes and showed a good performance.