• Journal of the Korea Organic Resources Recycling Association
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• v.5 no.1
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• pp.63-69
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• 1997

The role of L-glutamic acid, a precursor of $C_5$ ALA biosynthetic pathway, on the production of 5-aminolevulinic acid (ALA) has been described in cells of Rhodospirillum rubrum N-1. To the Lascelles basal medium the addition of both 30 mM L-glutamicacid and 20 mM levulinic acid (LA) provided to increase the extracellular ALA yield up to 40 fold (76 mg/l). By the addition of both 60 mM glycine and succinic acid, precursorsof $C_4$ ALA biosynthetic pathway, at middle log phase of cell growth ALA yield was increased 27 fold (52 mg/l) although the celt growth was inhibited to a certain extent.

• Korean Journal of Food Science and Technology
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• v.15 no.1
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• pp.56-61
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• 1983

Direct production of biomass from starch using amylolytic yeast, Sporobolomyces holsaticus FRI Y-5 was studied with varying the ratios between carbon and other nutrient sources in the medium. It was investigated under condition of constant C/P and C/S ratio to influence the initial concentration of starch $(S_o)$ and C/N ratio on its growth which is described as the specific growth rate $({\mu})$, cell yield (Y), the maximum concentration of cell $(X_m)$, and productivity (P). They were very dependent on both $S_o$ and C/N ratio. The form of the relationship between and ${\mu}$ and $S_o$ was observed to be similar to saturation kinetics at C/N = 100 but presented substrate inhibition at other C/N ratios. As $S_o$ was changed from 22.5 to 90 g/l, Y was observed to vary with C/N ratios but seemed to decrease as a wholes. $X_m$ was linearly related to $S_o$ at more than C/N = 50 but at less than C/N = 10 substrate inhibition was presented. P increased suddenly to $S_o$ = 45 g/l and then changed decreasingly at less than C/N = 50, but at more than C/N = 100 it changed increasingly. The effect of C/P ratio and C/S ratio on the yeast growth was also investigated at constant $S_o$ and C/N ratio. ${\mu}$ was dependent on C/P and C/S ratios, but Y, independent on them. But $X_m$ was reliant upon C/P ratio but not upon C/S ratio.

• Journal of Environmental Science International
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• v.25 no.11
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• pp.1493-1498
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• 2016

The efficiencies of Gang-Byeon sewage treatment facilities, which are based on GPS-X modelling, were analysed and used to design recycle water treatment processes. The effluent of an aeration tank contained total kjeldahl nitrogen (TKN) of 1.8 mg/L with both C-1 and C-2 conditions, confirming that most ammonia nitrogen ($NH_3{^+}-N$) was converted to nitrate nitrogen ($NO_3{^-}-N$). The concentrations of $NH_3{^+}-N$ and $NO_3{^-}-N$ were found to be 222.5 and 227.2 mg/L, respectively, with C-1 conditions and 212.2 and 80.4 mg/L with C-2 conditions. Although C-2 conditions with higher organic matter yielded a slightly higher nitrogen removal efficiency, sufficient denitrification was not observed to meet the discharge standards. For the total nitrogen (T-N) removal efficiency, the final effluent concentrations of T-N were 293.8 mg/L with biochemical oxygen demand (BOD) of 2,500 mg/L, being about 1.5 times lower than that (445.3 mg/L) with BOD of 2,000 mg/L. Therefore, an external carbon source to increase the C/N ratio was required to get sufficient denitrification. During the winter period with temperature less than $10^{\circ}C$, the denitrification efficiency was dropped rapidly even with a high TKN concentration (1,500 mg/L). This indicates that unit reactors (anoxic/aerobic tanks) for winter need to be installed to increase the hydraulic retention time. Thus, to enhance nitrification and denitrification efficiencies, flexible operations with seasons are recommended for nitrification/anoxic/denitrification tanks.

• Communications of the Korean Mathematical Society
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• v.32 no.4
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• pp.959-970
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• 2017

In this paper, we investigate the transcendental meromorphic solutions with finite order of two different types of difference equations $${\sum\limits_{j=1}^{n}}a_jf(z+c_j)={\frac{P(z,f)}{Q(z,f)}}={\frac{{\sum_{k=0}^{p}}b_kf^k}{{\sum_{l=0}^{q}}d_lf^l}}$$ and $${\prod\limits_{j=1}^{n}}f(z+c_j)={\frac{P(z,f)}{Q(z,f)}={\frac{{\sum_{k=0}^{p}}b_kf^k}{{\sum_{l=0}^{q}}d_lf^l}}$$ that share three distinct values with another meromorphic function. Here $a_j$, $b_k$, $d_l$ are small functions of f and $a_j{\not{\equiv}}(j=1,2,{\ldots},n)$, $b_p{\not{\equiv}}0$, $d_q{\not{\equiv}}0$. $c_j{\neq}0$ are pairwise distinct constants. p, q, n are non-negative integers. P(z, f) and Q(z, f) are two mutually prime polynomials in f.

• Korean Journal of Pharmacognosy
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• v.44 no.4
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• pp.336-343
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• 2013

In a continuation of investigation on Cordyceps militaris, thirteen compounds were isolated from the $CH_2Cl_2$ and n-BuOH-soluble fraction of C. militaris. They were identified as twelve diketopiperazines such as cyclo($\small{L}$-Gly-$\small{L}$-Pro) (1), cyclo($\small{L}$-Ala-$\small{L}$-Pro) (2), cyclo($\small{L}$-Ser-$\small{L}$-Pro) (3), cyclo($\small{L}$-Val-$\small{L}$-Pro) (4), cyclo($\small{L}$-Thr-$\small{L}$-Pro) (5), cyclo($\small{L}$-Pro-$\small{L}$-Pro) (6), cyclo($\small{L}$-Thr-$\small{L}$-Leu) (7), cyclo($\small{L}$-Tyr-$\small{L}$-Ala) (8), cyclo($\small{L}$-Phe-$\small{L}$-Ser) (9), cyclo($\small{L}$-Phe-$\small{L}$-Pro) (10), cyclo($\small{L}$-Tyr-$\small{L}$-Pro) (11) and brevianamide F (13), and an amino acid, tryptophan (12). Their structures were identified on the basis of chemical evidences and spectroscopic analysis including 1D-NMR ($^1H$, $^{13}C$), 2D-NMR (HSQC, HMBC) and MS spectral data. Among the isolated compounds, compounds 1, 2, 6-11 are first reported from C. militaris.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.571-586
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• 2014

Moderate Resolution Imaging Spectroradiometer (MODIS) provides air temperature (Tair) and dew point temperature (Tdew) profiles at a spatial resolution of 5 km. New Collection 6 (C006) MODIS07_L2 atmospheric profile product has been produced since 2012. The Collection 6 algorithm has several modifications from the previous Collection 5 (C005) algorithm. This study evaluated reliabilities of two alternative datasets of surface-level Tair and Tdew derived from C005 and C006 Aqua MODIS07_L2 (MYD07_L2) products using ground measured temperatures from 77 National Weather Stations (NWS). Saturated and actual vapor pressures were calculated using MYD07_L2 Tair and Tdew. The C006 Tair showed lower mean error (ME, -0.76 K) and root mean square error (RMSE, 3.34 K) than the C005 Tair (ME = -1.89 K, RMSE = 4.06 K). In contrasts, ME and RMSE of C006 Tdew were higher than those (ME = -0.39 K, RMSE = 5.65 K) of C005 product. Application of ambient lapse rate for Tair showed appreciable improvements of estimation accuracy for both of C005 and C006, though this modification slightly increased errors in C006 Tdew. The C006 products provided better estimation of vapor pressure datasets than the C005-derived vapor pressure. Our results indicate that, except for Tdew, C006 MYD07_L2 product showed better reliability for the region of South Korea than the C005 products.

• Journal of Ecology and Environment
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• v.38 no.2
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• pp.195-211
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• 2015

The objectives of this research were to determine mean and maximum tolerance ranges of Carassius auratus ($C_a$) and Cyprinus carpio ($C_c$) populations on various physico-chemical parameters and ecological indicator metrics. Little is known about chemical tolerance ranges of the two species, even though these species are widely distributed species in aquatic ecosystems. Maximum tolerance ranges of $C_a$-population to total nitrogen (TN) and total phosphorus (TP) were $20.3mgL^{-1}$ and $2.0mgL^{-1}$, respectively. Optimal ranges of TN and TP in the $C_a$-population were $1.7-5.0mgL^{-1}$ and $0.06-0.30mgL^{-1}$, respectively. Such nutrient regimes of the $C_a$-population were evaluated as hypereutrophy, indicating high tolerance limits. The $C_c$-population had similar ecological characteristics to $C_a$-population, but the mean tolerance ranges of TN, TP, BOD, and COD were significantly (p < 0.05) greater than the $C_a$-population. Ecological patterns of trophic composition and tolerance guilds in the $C_a$-population were similar to those of the $C_c$-population. The model value of Index of Biological Integrity (IBI) of the habitat where C. auratus and C. carpio co-occurred averaged $15.0{\pm}4.3$ and $12.9{\pm}3.6$, respectively. Based on the modified criteria of the United States Environmental Protection Agency (Klemm et al. 1993), it indicated poor ecological health of both species. These results suggest that both species are highly tolerant to chemical and physical habitat conditions of waterbodies, and that the chemical tolerance range of $C_c$-population was higher than $C_a$-population.

• Food Science and Preservation
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• v.18 no.3
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• pp.374-382
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• 2011

Aflatoxin ($AFB_1$) is a potent hepatotoxic and hepatocarcinogenic mycotoxin in humans. It is also well-known to be accumulated in animal tissues via various metabolic pathways. This study was conducted to determine the effects of vitamin C on the residual $AFB_1$ in rat sera that were treated with radiation and $AFB_1$. Six week-old male Sprague-Dawley rats were randomly divided into five groups: a control group, $AFB_1$-treated group, the group treated with $AFB_1$ and vitamin C, the group treated with X-ray and AFB1, and the group treated with X-ray and $AFB_1$ with vitamin C. On the first day of the experiment, only one dose of X-rays was exposed to the entire liver at 1,500 cGy. Next, vitamin C was injected at 10 mg/kg body weight via intraperitoneal injection, followed 1 hr later by the administration of 0.4 mg/kg of $AFB_1$ via intraperitoneal injection. These treatments were then administered every three days over a period of 15 days. On the 16th day of treatments, the animals were sacrificed. The contents of $AFB_1$ in rat sera were determined via indirect competitive ELISA and HPLC method. In the quantitative analysis of $AFB_1$ in rat sera via ELISA, $5.17{\pm}0.34$ ng/mL of $AFB_1$ was detected in the $AFB_1$-treated groups, but the amount more significantly decreased to $3.23{\pm}0.76$ ng/mL in the groups treated with $AFB_1$ and vitamin C (p<0.01) than in the $AFB_1$-treated groups. The $AFB_1$ contents of the rat sera of the groups treated with X-ray and $AFB_1$ did not significantly decreased with the administration of vitamin C. The $AFB_1$ content of the rat sera that was analyzed via HPLC showed a tendency similar to that of the content that was analyzed via ELISA. With regard to these data, vitamin C was very effective in reducing $AFB_1$ residue in rat sera.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.3
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• pp.383-393
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• 2020

The corrosion behavior of Hastelloy C-276 was investigated to identify its applicability for carbon-anode-based oxide reduction (OR), in which Cl₂ and O₂ are simultaneously evolved at the anode. Under a 30 mL·min^-1 Cl₂ + 170 mL·min^-1 Ar flow, the corrosion rate was less than 1 g·m^-2·h^-1 up to 500℃, whereas the rate increased exponentially from 500 to 700℃. The effects of the Cl₂-O₂ composition on the corrosion rate at flow rates of 30 mL·min^-1 Cl₂, 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂, and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂ with a constant 170 mL·min^-1 Ar flow rate at 600℃ was analyzed. Based on the data from an 8 h reaction, the fastest corrosion rate was observed for the 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂ case, followed by 30 mL·min^-1 Cl₂ and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂. The effects of the chlorine flow rate on the corrosion rate were negligible within the 5-30 mL·min^-1 range. A surface morphology analysis revealed the formation of vertical scratches in specimens that reacted under the Cl₂-O₂ mixed gas condition.

• Journal of Environmental Science International
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• v.30 no.11
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• pp.979-982
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• 2021

This study was conducted to investigate the effects of adding Tenebrio molitor L Powder to broiler feed on fatty acid profiles in broiler breast meat. In total, 180 broiler chicks (1-day old Arbor Acres) were included. The birds were randomly divided into control and treatment groups, with 3 replicate subgroups each(30 birds per subgroup), and fed a diet for 35 days without (control) or with 1% Tenebrio molitor L powder (treatment). Among individual fatty acids, addition of Tenebrio molitor L. powder resulted in slightly higher C18:1n-9, C20:3n-3 and C20:3n-6 contents, and lower C18:2n-6 content compared withcontrols (p<0.05). No remarkable differences in total SFA and total USFA contents were found between groups. In conclusion, inclusion of Tenebrio molitor L. in broiler diets did not improve overall fatty acid profiles.