• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.1-5
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• 2015

Lactic acid, the most widely occurring hydroxy-carboxylic acid, has traditionally been used as food, cosmetic, pharmaceutical, and chemical industries. Even though it has tremendous potential for large scale production and use in a wide variety of applications, high cost lactic acid materials are primarily problems. Lactic acid can be obtained on either by fermentation or chemical synthesis. In recent years, the fermentation approach has become more successful because of the increasing market demand for naturally produced lactic acid. Generally, lactic acid was produced from pure starch or from glucose. As an alternative, biomass which is the most abundant renewable resources on earth have been considered for conversion to readily utilizable hydrolysate. In this study, we conducted the fermentation method to produce L(+)-lactic acid production from pretreated hydrolysate was investigated by Lactobacillus rhamnosus ATCC 10863. The hydrolysate was obtained from pretreatment process of biomass using Ammonia percolation process (AP) followed by enzymatic hydrolysis. In order to effectively enhance lactic acid conversion and product yield, controlled medium, temperature, glucose concentration was conducted under pure glucose conditions. The optimum conditions of lactic acid production was investigated and compared with those of hydrolysate.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.121-126
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• 2015

The objective of this study is to evaluate the catalytic potential of the porous material prepared from water treatment sludge. The textural properties of the catalyst were studied using $N_2$ adsorption and desorption isotherms, scanning electron microscope, and X-ray diffraction. The pellet-type catalyst prepared using water treatment sludge is determined to be a material that contains mesopores as well as micropores. The specific surface area of the catalyst is $157m^2/g$. Acidic characteristics of the catalyst are analyzed by temperature-programmed desorption of ammonia and infrared spectroscopy of adsorbed pyridine. 2-Butanol dehydration reaction was carried out in a fixed bed catalytic reactor. Yields of 1-butene, trans-2-butene, and cis-2-butene at $350^{\circ}C$ were 25.6 wt%, 19.2 wt%, and 29.9 wt%, respectively. This catalytic activity of the catalyst based on water treatment sludge in 2-butanol dehydration is due to the acid sites composed of Bronsted acid sites and Lewis acid sites. It was confirmed that the catalyst based on water treatment sludge can be utilized to produce $C_4$ olefin through butanol dehydration.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.3
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• pp.357-364
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• 2014

The study evaluated replacement of Egyptian berseem clover (BC, Trifolium alexandrinum) with spent rice straw (SRS) of Pleurotus ostreatus basidiomycete in diets of lactating Baladi goats. Nine lactating homo-parity Baladi goats (average BW $23.8{\pm}0.4$ kg) at 7 d postpartum were used in a triplicate $3{\times}3$ Latin square design with 30 d experimental periods. Goats were fed a basal diet containing 0 (Control), 0.25 (SRS25) and 0.45 (SRS45) (w/w, DM basis) of SRS. The Control diet was berseem clover and concentrate mixture (1:1 DM basis). The SRS45 had lowered total feed intake and forages intake compared to Control. The SRS25 and SRS45 rations had the highest digestibilities of DM (p = 0.0241) and hemicellulose (p = 0.0021) compared to Control which had higher (p<0.01) digestibilities of OM (p = 0.0002) and CP (p = 0.0005) than SRS25 and SRS45. Ruminal pH and microbial protein synthesis were higher (p<0.0001) for SRS25 and SRS45 than Control, which also had the highest (p<0.0001) concentration of TVFA, total proteins, non-protein N, and ammonia-N. All values of serum constituents were within normal ranges. The Control ration had higher serum globulin (p = 0.0148), creatinine (p = 0.0150), glucose (p = 0.0002) and cholesterol (p = 0.0016). Both Control and SRS25 groups had the highest (p<0.05) milk (p = 0.0330) and energy corrected milk (p = 0.0290) yields. Fat content was higher (p = 0.0373) with SRS45 and SRS25 groups compared with Control. Replacement of BC with SRS in goat rations increased milk levels of conjugated linoleic acid and unsaturated fatty acids compared with Control. It was concluded that replacing 50% of Egyptian berseem clover with SRS in goat rations improved their productive performance without marked effects on metabolic indicators health.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.4
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• pp.494-501
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• 2015

A digestibility study was conducted to evaluate the effects of supplementing mulberry foliage and urea rice-bran as a source of fermentable energy and protein to 12 sheep fed diets based on urea-treated rice straw (TRS). The three dietary treatments were: T1, TRS with mulberry; T2, TRS with 50% mulberry replaced with rice bran and urea; and T3, TRS with rice bran and urea. The study was arranged in a completely randomized design with four replications for each treatment. The sheep were fed one of the three diets and the supplements were offered at 1.2% of the body weight (BW) and the TRS was provided ad libitum. There were no differences (p>0.05) among the three treatment groups with respect to dry matter (DM) intake ($76.8{\pm}4.2g/kg\;BW^{0.75}$) and DM, organic matter (OM), and crude protein (CP) digestibility ($55.3{\pm}1.22$; $69.9{\pm}0.85$; $46.3{\pm}1.65%$ respectively for DM, OM, and CP). The digestibility of fiber (neutral detergent fiber [NDF] and acid detergent fiber) was significantly lower (p<0.05) for T3 (46.2 and 46.6 respectively) compared to T1 (55.8 and 53.7 respectively) and T2 (54.1 and 52.8 respectively). Nitrogen (N) intake by sheep on diet T3 was significantly (p<0.05) higher than sheep fed diet T1. However, N balance did not differ among the three diets ($3.0{\pm}0.32g/d$). In contrast, the rumen ammonia ($NH_3-N$) concentrations in sheep fed T2 and T3 were significantly (p<0.05) higher than in sheep fed T1. The $NH_3-N$ concentrations for all three diets were above the critical value required for optimum rumen microbial growth and synthesis. Total volatile fatty acid concentrations were highest (p<0.05) in T1 (120.3 mM), whilst the molar proportion of propionic acid was highest in T3 (36.9%). However, the microbial N supply in sheep fed T1 and T3 was similar but was significantly (p<0.05) higher than for sheep fed T2. It was concluded that mulberry foliage is a potential supplement of fermentable energy and protein for sheep fed TRS based diet. The suggested level of supplementation is 1.2% of BW or 32% of the total diet since it resulted in similar effects on the intake of DM, OM, and NDF, digestibility of DM, OM, and CP, N utilization and microbial supply when compared to rice bran and urea supplementation.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.12
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• pp.1710-1718
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• 2016

The objective of this study was to evaluate the effects of supplements with different crude protein (CP) contents on grazing cattle intake, digestibility, ruminal fermentation pattern, and nitrogen (N) metabolism characteristics during the rainy season. Five ruminal and abomasal cannulated Holstein${\times}$Zebu steers (296 kg body weight, BW) were used in a $5{\times}5$ Latin square design. The animals grazed five signal grass paddocks (0.34 ha). The five treatments evaluated were: Control (no supplement) and 1.0 g of supplement/kg BW with 0, 330, 660, and 1,000 g of CP/kg as-fed. The supplement was composed of starch, soybean meal, urea, and ammonium sulphate. There was a positive linear effect ($p{\leq}0.033$) of the CP content in the supplements on the organic matter (OM), CP, and digested OM intakes. The provision of supplements did not increase ($p{\geq}0.158$), on average, total and ruminal digestibilities of OM and CP. However, the increase in CP content in the supplements caused a positive linear effect ($p{\leq}0.018$) on ruminal digestibilities of OM and CP. Additionally, a quadratic effect of the CP contents of the supplements were observed (p = 0.041) for the ruminal digestibility of neutral detergent fiber corrected for ash and protein, with the highest estimate obtained with the CP content of 670 g/kg. The supply of supplements increased (p<0.001) the ruminal ammonia N concentration, which also changed linearly and positively (p<0.001) according to increase in CP content in the supplements. The apparent N balance and relative N balance (g/g N intake) were not, on average, changed ($p{\geq}0.164$) by the supplements supply. However, both showed a tendency of a linear increase ($p{\leq}0.099$) with increasing supplement CP content. The supplements increased (p = 0.007) microbial N production in the rumen, which also changed linearly and positively (p = 0.016) with increasing supplement CP content. In conclusion, protein supplementation in grazing cattle during the rainy season, while stimulating voluntary forage intake, results in higher efficiency of N utilization when compared to energy supplementation. This is a possible response to increased microbial protein synthesis in the rumen and improved N status in the animal body.

• Polymer(Korea)
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• v.27 no.5
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• pp.470-476
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• 2003

In order to obtain high refractive plastic materials, 1,2 -ethylenedisulfanylbis(2-mercaptomethyl-1-ethanthiol) (ESTT) was newly prepared in good yield by the reaction of 1,2-ethylenedisulfanylbis(2-bromomethyl-1-ethanthiol) (ESTB) with thiourea followed by hydrolysis using an aqueous ammonia solution and characterized by $^1$H-NMR (-SH at 1.7 ppm), $\^$13/C-NMR(-CH$_2$SH at 28.4 ppm) and FT-IR (-SH at 2540 cm$\^$-1/) spectroscopy, etc. Polythiourethanes (PTU) were obtained from the combinations of ESTT with each of 4,4＇-methylenebis(phenylisocyanate) (MDI), tolyene 2,4-diisocyanate (TDI), isophorone diisocyanate (IPDI), mxylene diisocyanate (XDI), and 1,6-diisocyanatohexane (HMDI) in the presence of dibutyltin dilaurylate as a catalyst, in a casting mold, and characterized by FT-IR (existence of N=C=O) spectroscopy and elemental analyzer (sulfur content). Accordingly, their thermal, mechanical and optical properties were investigated by using DSC, TGA, hardness tester and refractometer: both the melting point on DSC and crystallinity on X -ray diffraction (XRD) for specimens of PTUs were not observed. PTUs with T$\_$g/s above 110 $^{\circ}C$ showed good hardness (Shore D) in the range of 86 to 89. Thermal stabilities of PTUs obtained by using ESTT and each of diisocyanates containing aromatic rings were especially good. Also, the optical transmittances of amorphous PTUs through UV-visible source in the range of 400 to 600 nm were good. PTUs showed refractive indexes above 1.60, and their refractive indexes gradually increased with increase of sulfur contents.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.587-598
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• 2000

Urea in the oral cavity is hydrolyzed mainly by bacterial ureases to ammonia, which in turn, raises pH of the oral environment, maintaining oral pH homeostasis, thereby inhibiting dental caries. Streptococcus salivarius has been shown to be a major contribution to oral ureolysis. Synthesis of urease by S. salivarius appears to be constitutive, but can be greatly enhanced in the acidic environment. It has been presumed that ureolytic activity of S. salivarius strains isolated from caries-active site is greater than that of strains from caries-free site. However, no in vivo study has supported the presumption. The present study was performed to observe the ureolytic activity of S. salivarius strains isolated from different environments in the same individual, finding out whether the ureolytic activity is related to dental caries. For the purpose, S. salivarius strains were isolated from caries-active site (>C2), a caries-free site of the tooth, and the dorsum of the tongue of each of 50 patients having decayed teeth. The strains isolated from the patients who harbored S. salivarius in more than two sites were selected and then their ureolytic activities were measured. In order to examine clonal diversity of the strains, their ureC genes were amplified by polymerase chain reaction (PCR) and then restricted with EcoRV, and the protein profiles of the strains were compared by SDS-PAGE. The results were as follows: 1. Of 50 patients, 13 patients harbored S. salivarius in more than two sites; a total of 61 S. salivarius strain were isolated from the patients and selected for the study. 2. Of 17 isolates from the caries-active site of 9 patients harboring S. salivarius in more than two sites including carious lesion, 10 (58.8%) showed a high ureolytic activity (> 200 ${\mu}mol/min/mg$). While, 19 out of 44 isolates (43.2%) from the caries-free site of the teeth and the dorsum of the tongues of 13 patients were the strains with a high ureolytic activity. 3. Of 9 patients harboring S. salivarius in more than two sites including caries-active site. 6 patients were found to have the strains in the caries-active site showing a lower ureolytic activity than the strains in the other sites. 4. Of 34 isolates with ureolytic activity higher than 40 ${\mu}mol/min/mg$, 32 isolates produced 0.54-Kbp PCR products regardless of the sites of bacterial collection. In contrast, of 27 isolates with ureolytic activity lower than 40${\mu}mol/min/mg$, 26 isolates yielded 1.3-Kbp PCR products or none regardless of the sites. 5. Different clonal types of S. salivarius with relatively higher and lower ureolytic activities were found in the same individuals and even in the same sites. 6. None of strains showing different ureolytic activity appeared to be the same clonal type. The overall results suggest that ureolytic activity of the isolates does not appear to be related to differences of the environments but related to their own genetic traits.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.543-553
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• 1996

Oxygen reduction in an alkaline fuel cell was studied by using perovskite type oxides as an oxygen electrode catalyst. The high surface area catalysts were prepared by malic acid method and had a formula of $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$(x=0.00, 0.01, 0.10, 0.20, 0.35 and 0.50). From the result of XRD pattern and specific surface area due to the amount of Fe substitution and the consumption of ammonia-water, the complex formation of Fe ion with $NH_3$ was the main factor for both the phase stability of perovskite and the increase of specific surface area. Multi-step calcination was necessary to give a single phase of perovskite in catalyst precursor. The crystal structure of the catalysts was simple cubic perovskite, which was verified from the XRD patterns of the catalysts. The activity of oxygen reduction was monitored by the techniques of cyclic voltammetry, static voltage-current method, and current interruption method. The activity(current density) of oxygen reduction showed its minimum at x=0.01 and its maximum between 0.20 and 0.35 of x-value in $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$. This tendency was independent of the change of surface area.

• KSBB Journal
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• v.29 no.1
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• pp.58-66
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• 2014

Demand for in vitro pharmacological evaluation and toxicity test using human hepatocytes has been increasing. In USA and Europe, human hepatocytes obtained from donated whole liver unsuitable for transplantation were distributed to researchers and deposited in cell bank facility as cryopreserved vial. In Korea, however, incidence of transplantation- inappropriate whole liver has been quite low and the whole livers almost have so severe liver disease such as fatty or fibrotic liver that cannot meet the demand. In this study we aimed to isolate human hepatocytes from liver resection surgery-originated partial liver, and assure the isolated human hepatocytes and its cryopreserved hepatocytes to be qualified for the in vitro pharmacological evaluation and drug toxicity tests. We compared those with commercially available human hepatocyte, BD $GenTest^{TM}$ by cell morphology, hepatic gene expression, urea synthesis, albumin secretion, ammonia removal, and cytochrome P450 induction activities. Changes in hepatotoxic gene expression after cryopreservation are evaluated with a typical hepatotoxic drug, acetaminophen. Consequently, the fresh hepatocytes from the partial liver and its cryopreserved hepatocytes expressed their intrinsic hepatic functions well and showed equal hepatotoxicity gene expression trend regardless to cryopreservation. Therefore, liver resection surgery-originated partial liver can be used as a useful source of human hepatocytes for various pharmacological and hepatotoxicity test.

• Clean Technology
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• v.14 no.3
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• pp.204-210
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• 2008

A series of $V_{2}O_{5}-TiO_2$ xerogel catalysts were prepared by nonhydrolytic sol-gel method and analysed by various characterization techniques. These catalysts showed much higher surface areas and total pore volumes than conventional V$V_{2}O_{5}-TiO_2$ xerogel and impregnated $V_{2}O_{5}/TiO_2$ catalysts. It was found that the textural property of $V_{2}O_{5}-TiO_2$ material varies with the method and conditions of synthesis. Surface vanadates and $TiO_2$ anatase phase are the crucial factors to obtain high catalytic activities. The selective oxidation of hydrogen sulfide in the presence of excess water and ammonia was studied over these catalysts. Xerogel catalysts prepared by non-hydrolytic sol-gel method showed very high conversion of $H_{2}S$ without harmful emission of $SO_2$. The highest catalytic activity shown by these $V_{2}O_{5}-TiO_2$ catalysts may be due to their high surface area and good dispersion of vanadia species in the titania matrix.