• KSBB Journal
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• v.30 no.6
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• pp.319-325
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• 2015

Arthrospira platensis (A. platensis) is one of the most explored cyanobacteria and has been studied for proteins, vitamins, pigment (chlorophyll and carotenoids) and fatty acid. In this study, we tested the effect of $NaHCO_3$ and $NaNO_3$ on the microalgae growth under photoautothrophic culture in A. platensis. As a result, cell growth and dry cell weight were increased in proportion to the $NaHCO_3$ and $NaNO_3$ concentration. Pigment (chlorophyll and carotenoids) contents of A. platensis were increased with proportion to $NaHCO_3$ concentration. But, the content of pigment (chlorophyll and carotenoids) in 100% $NaNO_3$ medium of A. platensis was the highest, 40%, 140% and 200% $NaNO_3$ medium with pigment content of A. platensis was reduced. In conditions of $NaHCO_3$ (50%) or $NaNO_3$ (40%) limitation, A. platensis could accumulate lipids to high as 1.7-fold and 1.3-fold.

• The Journal of Korean Medicine
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• v.16 no.1 s.29
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• pp.281-294
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• 1995

The effect of Sam Hwa San on the Na-K-ATPase activity was evaluated in microsomal fraction prepared from rabbit cerebral cortex to determine whether Sam Hwa San affects Na-K-ATPase activity of nervous system. Sam Hwa San markedly inhibited the Na-K-ATPase activity in a dose-dependent manner with an estimated $I_{50}$ of 0.12%. Optimal pH for the Na-K-ATPase activity was at 7.5 in the presence or absence of Sam Hwa San. The degree of inhibition by the drug more increased at acidic and alkalic pHs than neutral pH. Kinetic studies of substrate and cationic activation of the enzyme indicate classic noncompetitive inhibition fashion for ATP, Na and K, showing significant reduction in Vmax without a change in Km. Dithiothreitol, a sulfhydryl reducing reagent, partially protects the inhibition of Na-K-ATPase activity by Sam Hwa San. Combination of Sam Hwa San and ouabain showed higher inhibition than cumulative inhibition. These results suggest that Sam Hwa San inhibits Na-K-ATPase activity in central nervous system by reacting with, at least a part, sulfhydryl group and ouabain binding site of the enzyme protein, but with different binding site from those of ATP, Na and K.

• Journal of Magnetics
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• v.20 no.4
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• pp.342-346
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• 2015

The nuclear magnetic resonance of the $^{23}Na$ nucleus in a $NaBrO_3$ single crystal was investigated at the temperature range of 200 K~410 K. The tendencies of temperature dependence of the nuclear quadrupole coupling for the two magnetically inequivalent Na(I) and Na(II) centers are found to be opposite to each other. The nuclear spin-lattice relaxation mechanism of $^{23}Na$ in the $NaBrO_3$ crystal is investigated, and the result revealed that the Raman process is dominant in the temperature range investigated. The relaxation process of the $^{23}Na$ nuclear spins was well described by a single exponential function in time. The $T_1$ values of the $^{23}Na$ nuclei in the $NaBrO_3$ single crystal decreased with increasing temperature. The calculated activation energy for the $^{23}Na$ is $0.032{\pm}0.002eV$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.271-278
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• 2004

This study was conducted to obtain basic information of growth, chlorophyll, and $Na^+\;and\;K^+$ content of rice (Oryza sativa L.) seedlings after transplanting in different NaCl conditions. Plants grown in pots for 8 days after germination were grown for 10 days after transplanting in 50 and 100 mM NaCl concentrations. At higher NaCl concentration, plant height, root length, dry weight and chlorophyll content were reduced with NaCl stress. Among rice cultivars, the shoot dry weight of Gancheokbyeo, Janganbyeo and Hwasungbyeo, and the root dry weight of Janganbyeo, Gancheokbyeo and Juanbyeo showed relatively low reduction compared to the other rice cultivars at 100 mM NaCl stress. The $Na^+$ content in seedling rapidly increased with the increase of NaCl concentration but $K^+$ contents decreased. There was a significant relationship between $Na^+$ content and shoot and root dry weight after transplanting rice seedlings to saline conditions. The shoot and root dry weight showed highly negative relationship with the $Na^+/K^+$ ratio in saline conditions.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.322-326
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• 2010

Stability of sodium borohydride solution during storage was studied. In order to enhance the $NaBH_4$ stability, NaOH and KOH were added to the $NaBH_4$ solution. The effect of concentration of the borohydride and alkaline solution, temperature and materials of storage vessels on the rate of borohydride hydrolysis was investigated. The rate of hydrogen evolution decreased as the concentration of alkaline increased due to increase of $NaBH_4$ stability in the solution. The stability of $NaBH_4$ solution decreased when the borohydride concentration raised from 10 to 15 wt% and then increased when the $NaBH_4$ concentration increased above 15 wt% due to increase in the pH of the concentrated solution. The activity coefficient of hydrolysis of $NaBH_4$ solution(NaOH 3.0 wt%, $NaBH_4$ 25 wt%) was 115.1 kJ/mol and this value was 1.5~4.0 times higher than that of hydrolysis of $NaBH_4$ solution with catalyst. The borohydride solutions in glass and stainless-steel vessel were more stable than the solution in plastic(PE) vessel.

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.232-237
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• 2005

This study was conducted to elucidate the effects of NaOH fusion treatment on Na-P1 zeolite synthesis from fly ash and to evaluate its optimal condition. NaOH fusion treatment of fly ash led to Na-P1 zeolite with shorter reaction time and higher quality compared that of simple hydrothermal method. Mixed zeolite phases of Na-P1 and hydroxy sodalite were formed by the fusion treatment below $450^{\circ}C$, whereas only Na-P1 zeolite was formed above $550^{\circ}C$. Ratio of NaOH/fly ash, reaction times, fusion temperature and solid/liquid ratio strongly affected the kind and crystallinity of the zeolite formed. The CEC of Na-P1 zeolite formed at the optimum reaction conditions of NaOH/fly ash ratio 0.9 and solid/liquid ratio $1/5.0{\sim}1/7.5$ after NaOH fusion treatment at $550^{\circ}C$ for 2 hours was about $398cmol^+kg^{-1}$ which was 40% higher than those of control products. Therefore, it is clear that NaOH fusion treatment of fly ash in open system could lead to Na-P1 zeolite with high purity.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.342-347
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• 2001

The experiment was carried out to examine the effect of culture media and seawater on growth and mineral concentrations in Glasswort (Salicornia herbacea). Glassworts were grown in a greenhouse with 0, 10, 30 and 90% seawater and with or without nutrient media. The salinity tolerance affected on shoot height and Na, K and Ca concentrations significantly. The shoot height was increased with 10 and 30% seawater concentrations. At the higher seawater concentrations, more Na accumulated in a shoot was obserbed. The application of seawater concentration was effective on increasing Na, Mg, and Fe, concentrations and green leaf area rate and on decreasing K concentration. K/Na ratio of shoot was decreased at high seawater concentration, whereas Na concentrations was lowered at a low seawater concentrations. The mineral concentrations were changed according to the growing season. Na, K and Mg were high in June and Ca and P in September, respectively.

• The Korean Journal of Physiology
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• v.7 no.1
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• pp.41-47
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• 1973

$Na^{+}$ balance was studied in Rana temporaria, which hibenates in fresh water in the winter time. $Na^{+}$ uptake rate, skin $Na^{+}$ loss rate, urinary $Na^{+}$ loss rate and $Na^{+}-K^{+}$ adenosine triphosphatase(ATPase) were measured at two different temperatures $1{\sim}2^{\circ}C\;and\;20{\sim}24^{\circ}C$ respectively. The results obtained were as follows: 1. $Na^{+}$ uptake rates in the frog in an artificial Pond water (APW) were found to be $8.28{\pm}0.73\;and\;2.19{\pm}0.37\;{\mu}Eq/g/day\;at\;20{\sim}24^{\circ}C\;and\;1.0{\sim}2.5^{\circ}$ respectively. 2. $Na^{+}$ loss rate through the frog skin to APW were found to be $4.26{\pm}0.72\;and\;0.93{\pm}0.21\;{\mu}Eq/g/day$ at the same temperatures. 3. Mean rates of urinary $Na^{+}$ loss at $20{\sim}24^{\circ}C\;and\;3{\sim}4^{\circ}C$ were found to be $3.02{\pm}0.73\;and\;0.78{\pm}0.13\;{\mu}Eq/g/day$ respectively. 4. The activities of $Na^{+}-K^{+}$ activated ATPase of frog skin fragments were found to be $258{\pm}39.4\;and\;49.6{\pm}7.1\;{\mu}M\;Pi/g$ protein/hr at $24^{\circ}C\;and\;2^{\circ}C$ respectively. From the above results, it may be concluded that frogs can take up enough $Na^{+}$ through the skin from APW exceeding skin loss Plus urinary loss at $1{\sim}2^{\circ}C$. It is suggested that $Na^{+}$ transport across frog skin is closely related with $Na^+-K^+$ ATPase since $Q_{10}\;of\;Na^{+}$ uptake is much similar to that of the activities of $Na^{+}-K^{+}$ ATPase.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.689-694
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• 2009

Layer-structured $Na_xCo_2O_4$ was synthesized from $Na_2CO_3\;and\;Co_3O_4$ powders. The chemical concentrations of Na and additive were controlled to enhance the thermoelectric properties over the temperature range from 400 K to 1,150 K. As a result, we obtained the maximum thermoelectric properties at a single phase region with Na content of x=1.5. When Na content was smaller than x=1.5, the thermoelectric properties was low due to formation of second phases of CoO and other oxides. Additionally, Mn was doped to improve thermoelectric properties by means of decreasing thermal conductivity. The results showed that the concentrations of both Na and Mn are all governing factors to determine the thermoelectric properties of $Na_xCo_2O_4$ system.

• Carbon letters
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• v.16 no.2
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• pp.116-120
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• 2015

We investigated the adsorption of Na on graphene and graphene oxide, which are used as anode materials in sodium ion batteries, using density functional theory. The adsorption energy for Na on graphene was -0.507 eV at the hollow sites, implying that adsorption was favorable. In the case of graphene oxide, Na atoms were separately adsorbed on the epoxide and hydroxyl functional groups. The adsorption of Na on graphene oxide-epoxide (adsorption energy of -1.024 eV) was found to be stronger than the adsorption of Na on pristine graphene. However, the adsorption of Na on graphene oxide-hydroxyl resulted in the generation of NaOH as a by-product. Using density of states (DOS) calculations, we found that the DOS of the Na-adsorbed graphene was shifted down more than that of the Na-adsorbed graphene oxide-epoxide. In addition, the intensity of the DOS around the Fermi level for the Na-adsorbed graphene was higher than that for the Na-adsorbed graphene oxide-epoxide.