• Ocean and Polar Research
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• v.44 no.3
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• pp.209-220
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• 2022

Carbonic anhydrase (CA) is a key controller of the carbon concentrating mechanism (CCM), and is known to be affected by ambient pH and CO₂ compositions. Herein, we characterized three novel CAs genes (PmCA1, 2, and 3) from the marine dinoflagellate Prorocentrum minimum, and evaluated the relative expressions of the PmCAs and photosynthetic genes PmatpB and PmrbcL under different pH conditions. Each PmCA was predicted to have amino acid residues constituting the zinc binding site. With signal peptide, PmCA1 and PmCA2 were predicted to be intracellular CAs located in the cytoplasm and chloroplast membrane, respectively. On the other hand, PmCA3 was predicted to be extracellular CA located in the plasma membrane. Also, PmCA1 was classified into the beta family, and PmCA2 and PmCA3 were classified into the alpha family via phylogenic analysis. The photosynthesis efficiency of P. minimum was similar at pH 7 to 9, and decreased significantly at pH 6 and pH 10. Overall, relative gene expression levels of the three PmCAs decreased at low pH, and increased as pH increased. Photosynthesis related genes, PmatpB and PmrbcL, showed similar expression patterns to those of PmCAs. These results suggest that changes in seawater pH may affect photosynthesis and CO₂ metabolism in marine dinoflagellates.

• Steel and Composite Structures
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• v.31 no.1
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• pp.85-98
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• 2019

Nonlinear seismic performances of code designed Perforated Steel Plate Shear Walls (P-SPSW) were studied. Three multi-storey (4-, 8-, and 12-storey) P-SPSWs were designed according to Canadian seismic provisions and their performance was evaluated using time history analysis for ground motions compatible with Vancouver response spectrum. The selected code designed P-SPSWs exhibited excellent seismic performance with high ductility and strength. The current code equation was found to provide a good estimation of the shear strength of the perforated infill plate, especially when the infill plate is yielded. The applicability of the strip model, originally proposed for solid infill plate, was also evaluated for P-SPSW and two different strip models were studied. It was observed that the strip model with strip widths equal to center to center diagonal distance between each perforation line could reasonably predict the inelastic behavior of unstiffened P-SPSWs. The strip model slightly underestimated the initial stiffness; however, the ultimate strength was predicted well. Furthermore, applicability of simple shear-flexure beam model for determination of fundamental periods of P-SPSWs was studied.

• Membrane Journal
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• v.23 no.4
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• pp.290-296
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• 2013

Poly(vinylidenefluoride-co-chlorotrifluoroethylene) P(VDF-co-CTFE) polymer was attached to methacrylic acid (MAA) in the presence of 1,8-diazabicyclo[5,4,0]undec-7-ene(DBU) catalyst to prepare P(VDF-co-CTFE)-MAA copolymer. The modified P(VDF-co-CTFE)-MAA was polymerized with 2-sulfoethyl methacrylate (SEMA) monomer in the presence of 4',4'-azobis(4-cyanovaleric acid(ACVA) initiator by free radical polymerization to form the proton conducting membrane. The ratio of the SEMA was increased in the membrane to increase the presence of the acidic group. The maximum IEC value that was observed at 50% SEMA was around 0.82 meq/g, which is consistent with the water uptake value. The highest proton conductivity achieved by P(VDF-co-CTFE)-MAA/SEMA membrane with 50% SEMA was approximately 0.041 S/cm. This indicates that the available ionic group for the proton conduction increases with the increase in the SEMA in the membrane.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.752-757
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• 2011

The effects of reaction temperature, reactant concentration, pH of solution and mixing order of reactants on the particle shape and size distribution of zinc oxide were investigated in the preparation of zinc oxide from ammonium hydroxide and zinc acetate by the method of aqueous hydrothermal precipitation method, and the photocatalytic ability of zinc oxide synthesized was measured from the degradation of tartrazine under UV irradiation. The average particle size was increased with pH of solution but decreased with zinc acetate concentration and reaction temperature. The optimum condition for the synthesis of minimum sized zinc oxide was pH 11.2, concentration of zinc acetate 0.6 M and reaction temperature $90^{\circ}C$, and its average particle size was 3.133 ${\mu}$m. 97% of tartrazine was degraded by zinc oxide in sixty minutes.

• The Plant Pathology Journal
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• v.24 no.1
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• pp.74-79
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• 2008

This research was conducted to evaluate fungal and bacterial populations in unhulled and brown rice under indoor storage conditions, and to examine the relationship between microbial populations and environmental conditions such as temperature and relative humidity. The temperature and relative humidity of the storage room ranged from $22.6^{\circ}C\;to\;27.0^{\circ}C$ and 23.3% to 44.2%, respectively. Total fungal and bacterial populations remained relatively stable over the storage period. Predominant fungi included Aspergillus candidus, A. flavus, A. fumigatus, and Penicillium spp.; the predominant bacteria were Bacillus, Microbacterium, Sphingomonas, and Methylobacterium spp. Total fungi and bacteria were not significantly correlated with either unhulled (r=0.448, P=0.372) or brown (r=0.466, P=0.351) rice. In unhulled rice, total fungi showed positive correlations with total Aspergillus (r=0.994, P<0.001) and total Penicillium (r=0.906, P<0.05); A. flavus was positively correlated with total Aspergillus (r=0.913, P<0.05) and total fungi (r=0.868, P<0.05). In brown rice, Bacillus spp. was also positively correlated with total bacteria (r=0.998, P<0.001). Mean temperature was negatively correlated with A. candidus (r=-0.852, P<0.05) and total fungi (r=-0.961, P<0.01), and mean relative humidity was positively correlated with total Penicillium spp.(r=0.884, P<0.05) in brown rice. Hence these results could provide basic information on the fungal and bacterial populations in unhulled and brown rice stored under room conditions, and on the effect of environmental conditions on the populations of fungi and bacteria, especially Aspergillus and Penicillium spp.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.431-439
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• 2014

We report the construction of two Bacillus subtilis expression vectors, pBNS1/pBNS2. Both vectors are based on the strong promoter P43 and the ampicillin resistance gene expression cassette. Additionally, a fragment with the Shine-Dalgarno sequence and a multiple cloning site (BamHI, SalI, SacI, XhoI, PstI, SphI) were inserted. The coding region for the amyQ (encoding an amylase) signal peptide was fused to the promoter P43 of pBNS1 to construct the secreted expression vector pBNS2. The applicability of vectors was tested by first generating the expression vectors pBNS1-GFP/pBNS2-GFP and then detecting for green fluorescent protein gene expression. Next, the mannanase gene from B. pumilus Nsic-2 was fused to vector pBNS2 and we measured the mannanase activity in the supernatant. The mannanase total enzyme activity was 8.65 U/ml, which was 6 times higher than that of the parent strain. Our work provides a feasible way to achieve an effective transformation system for gene expression in B. subtilis and is the first report to achieve B. pumilus mannanase secretory expression in B. subtilis.

• Journal of Microbiology and Biotechnology
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• v.7 no.6
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• pp.391-396
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• 1997

Two series of carbon sources, linear primary $C_1$~$C_9$ alcohols and linear $C_2$~$C_{10}$ monocarboxylic acids were tested for PHA synthesis in Paracoccus denitrificans. The results showed that the growth-associated synthesis of PHA could be referred only to the carbon sources with odd number of carbon except methanol. For all carbon sources with even number of carbon, nitrogen limitation was required to induce PHA synthesis in P. denitrificans. Poly(3-hydroxyvalerate)[P(3HV)] homopolymer was synthesized from $C_5$, $C_7$, and $C_9$ while growing in the presence of nitrogen, but the nitrogen depletion in the later growth period incorporated 3-hydroxybutyrate(3HB) unit into the polymer chain. The optimum C/N ratio for P(3HV) homopolymer production was found to be 10 when the strain was grown on 10 ml/l of valeric acid for 96 h. P. denitrificans synthesized P(3HB-co-3HV) copolymers from n-hexanoic and n-octanoic acid. The microstructural characterics of the P(3HB-co-3HV) copolymer from n-propanol was investigated using $^13C$-nuclear magnetic resonance spectroscopy, showing a structural heterogeneity.

• Journal of the Korean Applied Science and Technology
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• v.14 no.1
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• pp.27-32
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• 1997

Furfurylidene acetophenone derivatives were synthesis, it was measured that nucleophilic addition made use of UV at a wide pH 1.0${\sim}$13.0 range in 30% dioxane-$H_2O$ solution, 25$^{\circ}C$. On the basis of general base catalysis, substitutent effect, confirmation of nucleophilic addition products, it was measured the reaction rate of furfurylidene acetophenone derivatives for the pH change. It may be concluded that a part was unrelated to pH and another part was in proportion to concentration of hydroxide ion: Above pH 10.0. sulfide anion adds to the double bond (Michael type addition), a part having no concern with pH, addition reaction to double bond is initiated by addition of neutral thiourea molecule. From the result of measurement the reaction rate, nucleophilic addition of furfurylidene acetophenone derivatives confirmed to the irreversible first order. Through measurement the substituent effect. It found that reaction rate was accelerated by electron attracting group. On the basis of these findings, nucleophilic addition of thiourea for the furfurylidene acetophenone derivative was proposed a fitting mechanisms.

• Journal of the Korean Applied Science and Technology
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• v.12 no.2
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• pp.107-113
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• 1995

Benzoyl styrene derivatives were synthesized by Claisen-Schmidt condensation. It was measured that nucleophilic addition of thiourea for benzoyl styrene made use of ultraviolet spectrophotometery at a wide pH $1.0{\sim}13.0$ range in 5% $dioxane-H_2O$ at $40^{\circ}C$. On the basis of general base catalysis, substitutent effect, and confirmation of addtion reaction product, the nucleophilic addtion kinetics of thiourea for benzoylstyrene derivatives were measured by pH change. It maybe concluded that a part was unrelated to pH and another part was in proportion to concentration of hydroxide ion : Above pH 10.0. It was in propotion to concentration of hydroxide ion, a part having no concern with pH was added to the neutral thiourea molecule. From the results of measurement the reaction rate and there findings, nucleophilic addition of thiourea to benzoylstyrene derivative was proposed a fitting mechanism.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.301-311
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• 2018

In this study, the ion-gelation method was applied to fabricate novel Fe-carbon-bentonite-alginate beads ($Fe^0$/C-BABs). $Fe^0$/C-BABs could effectively control Fe release during persulfate (PS) activation in N-acetyl-p-aminophenol (APAP) oxidation. A novel two-stage approach that combined $Fe^0$/C-BABs and an oyster-shell-filled bed (OSFB) column was developed to address the low pH and high Fe concentration of the effluent of the traditional PS process. The application of the $Fe^0$/C-BABs and OSFB column regulated pH levels and Fe release during the advanced oxidation of APAP. The characteristics of $Fe^0$/C-BABs were also investigated through scanning electron microscopy, energy dispersive spectrometry, and Fourier transform infrared spectroscopy. The long-term operation performance of $Fe^0$/C-BABs in a continuous fixed-bed reactor under simultaneous PS and APAP feeding was also evaluated. The effects of initial PS concentration, pH, fixed-bed weight, in-flow rate, and dissolved oxygen (DO) were investigated. Under selected conditions, 86.3% efficiency was achieved during the first stage of APAP degradation (effluent pH of 3.05, Fe contents: $106.25mgL^{-1}$). Water quality improved after the effluent was passed through the OSFB column (effluent pH of 6.32, Fe contents: $21.43mgL^{-1}$). Moreover, this study analyzed the free radicals and intermediates produced during APAP degradation to identify the possible routes of APAP degradation.