• Asian-Australasian Journal of Animal Sciences
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• 제18권9호
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• pp.1273-1278
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• 2005

This study is to evaluate the effect of different levels of ensiling density on the fermentation quality of guineagrass silages during the early stage of ensiling. Guineagrass at the milky ripe stage was chopped and ensiled into a small-scale laboratory silo at two ensiling density levels (high density at 95 g/silo and low density at 75 g/silo). Three silos per level were opened after six ensiling periods (0.5, 1, 1.5, 2, 3 and 7 days of ensiling) and the fermentation qualities were analyzed. Within the initial 1.5 days of ensiling there were not significant (p>0.05) differences in the fermentation qualities between two density levels silages, and an almost constant pH and no or only small amounts of lactic acid, acetic acid and total volatile fatty acids were detected. However, the high density silage significantly (p<0.05) increased the rate and extent of fermentation after 1.5 days of ensiling, which was well reflected in significantly (p<0.05) faster and larger pH decline and lactic acid production at each elapsed time as compared with the low density silage. This resulted in significantly (p<0.05) lower finial pH and significantly (p<0.05) higher lactic acid content at the end of the experiment. Moreover, there was higher AA content relative to LA in both the H-D and L-D silages during the full fermentation course, and resulted in the AA-type silage. There were generally somewhat or significantly (p<0.05) higher acetic acid, volatile fatty acids and ammonia-N/total nitrogen in the high density silage than in the low density silage during the initial 3 days of ensiling. However, there were higher (p>0.05) ammonia-N/total nitrogen and significantly (p<0.05) higher butyric acid content in the low density silage at day 7 of ensiling. The silages of two density levels showed an initial increase in glucose between 0.5 and 1 day for the high density silage and between 1 and 1.5 days for the low density silage, respectively, thereafter showed a large decrease until the end of the experiment. There were not large differences (p>0.05) in ethanol content between the low density and high density silages that showed small amounts within initial 3 days of ensiling. However, the low density silage had a significantly (p<0.05) higher ethanol content than the high density silage at the end of experiment. From the above results it was suggested that the increase in ensiling density was an effective method to improve the fermentation quality, especially for tropical grasses.

• 한국수산과학회지
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• 제31권1호
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• pp.127-131
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• 1998

추출용매비 및 추출시간을 각각 50배 (w/v), 3시간으로 일정하게 하고 추출온도 ($60\~100^{\circ}C$)와 pH($2.0\~13.5$)를 달리하면서 crude porphyran을 제조하여 수율과 화학조성 을 조사하였다. Crude porphyran의 화학조성은 추출온도와 pH에 따라 크게 달라져서 산성영역에서 추출한 crude porphyran은 중성영역에서 추출한 것에 비해 수율 및 황산기 함량은 더 많으면서 단백질을 더 적게 함유하나 분자량도 작아지는 것으로 나타났고, 알칼리 영역에서 추출하는 경우는 황산기가 떨어져 나가고 단백질의 혼입량이 많아지는 것으로 나타났다. 따라서 실험목적에 따라 추출조건이 달라져야 함을 알 수 있었는데 수율의 증가 및 저분자화를 위해서는 pH $3\~4$의 조건이, 그리고 시료내 존재하는 porphyran을 분자량의 변화 없이 추출하기 위해서는 중성 영역에서 추출하는 것이 적절할 것으로 사료된다.

• Journal of Animal Science and Technology
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• 제47권1호
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• pp.11-18
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• 2005

The objective of this study was to estimate the effects of daily milk yield, somatic cell count(SCC), days in milk(DIM), and parity on the compositions of milk and blood in high or low producing dairy cows. To divide the high or low producing group, there were some restrictions in this study. 235 Holstein dairy cows had a average daily milk yield of 23.2 $\pm$ 6.8 kg were grouped into two classes with low producing(average daily milk 17kg) or high producing(average daily milk 29 kg). The other restrictions were two parities(first and second parity), two SCC groups(under $l{\times}10^5$cells/ml, and $l{\times}10^5$ to $7{\times}10^5$ celis/ml), and three DIM groups(under 80, 81 to 180, and 181 to 305DIM). The blood urea nitrogen(BUN), milk urea nitrogen(MUN) and glucose between two group with high and low somatic cell count were not affected by parity, DIM and SCC. But there were significantly different on BUN and glucose between high and low milk producing(p< 0.01), also was different on glucose between parities(p < 0.05). White blood cell(WBC) and lymphocyte were affected(p< 0.05) by SCC level, protein percent was also affected by DIM(p< 0.01). The least square means of protein in second parity was a 1.3 times higher than that in first parity(p < 0.05), and it showed a higher level in the low producing group than the high producing group(p < 0.0l). WBC and lymphocyte were lower in the $1{\sim}7{\times}10^5$ celis/ml than those under $1{\times}10^5$ celis/ml(p< 0.05). Neutrophil was a higher level in first parity than that in second parity(p < 0.05). Only protein and total solid were affected by parity, the other compositions were not affected by parity, DIM, SCC and milk yields. The results suggested that significant differences were in the blood components such as glucose, WBC, lymphocyte and neutrophil between high and low producing cows. The results also show that more studies are required to clarify the factors and markers related to milk yield, quality and mastitis.

• Applied Biological Chemistry
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• 제20권3호
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• pp.300-309
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• 1977

The information related to the heavy metal pollution in the environment was obtained from studies on the effects of pH, phosphate and soil properties on the adsorption of metal ions (Cd, Cu, Ni, and Zn) by soils. Three soil materials; soil 1 with low CEC (8.2 me/100g) and low organic carbon content (0.34%); soil 2 with high CEC (36.4 me/100g) and low organic carbon content (1.8%) and soil 3 with high CEC (49.9 me/100g) and high organic carbon content (14.7%) were used. Soils were adjusted to several pH's and equilibrated with metal ion mixtures of 4 different concentrations, each having equal equivalents of each metal ion (0.63, 1.88, 3.12 and 4.38 micromoles per one gram soil with and without 10 micromoles of phosphate per one gram soil). Reported here are the results of the equilibrium study on soil I. The rest of the results on soil 2 and soil 3 will be repoted subsequeutly. Generally higher metal ion concentration solution resulted in higher final metal ion concentrations in the equilibrated solution and phosphate had minimal effect except it tended to enhance removal of cadmium and zinc from equilibrated solutions while it tended to decrease the removal of copper and nickel. In soil 1, percentages of added metal ions removed at pH 5.10 were; Cu 97, Ni 69, Cd 63, and Zn 55, while increasing pH to 6.40, they were increased to Cu 90.9, Zn 99, Ni 96, and Cd 92 per As initial metal ion concentration increased, final metal ion concentrations in the equilibrated solution showed a relationship with pH of the system as they fit to the equation $p[M^{++}]=a$ pH+b where $p[M^{++}]=-log$[metal ion concentration in Mol/liter]. The magnitude of pH and soil effects were reflected in slope (a) of the equation, and were different among metal ions and soils. Slopes (a) for metal ions in the aqueous system are all 2. In soil 1 they were; Zn 1.23, Cu 0.99, Ni 0.69 and Cd 0.59 at highest concentration. The adsorption of Cd, Ni, and Zn in soil 1 could be represented by the Iangmuir isotherm. However, construction of the Iangmuir isotherm required the correction for pH differences.

• 한국초지조사료학회지
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• 제37권1호
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• pp.1-9
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• 2017

This research was conducted to investigate the effects of feeding high and low forage diets with different forage sources on rumen fermentation characteristics and blood parameters of Holstein cows during the dry period. Eight Holstein cows were completely randomized assigned to two groups and repeated measurement was utilized in the analysis. Cows in two treatments were fed with diets with high (F:C = 70:30, 70F; forage source: mixed-sowing whole crop barley and Italian ryegrass silage, BIRG) and low (F:C = 55:45, 55F; forage source: tall fescue hay, TF) forage level. Rumen fluid pH was higher in 70F group. Levels of acetic acid, propionic acid, and butyric acid showed a similar pattern: from the lowest value at 07:30 h to the highest at 10:30 h and then decreased in both groups. The ratio of acetic acid to propionic acid was significantly higher (p < 0.05) in 55F group at 09:30 and 10:30 h. Rumen fluid $NH_3-N$ concentrations were significantly higher (p < 0.05) in 70F group at 09:30 and 10:30 h. Blood urea nitrogen was significantly higher (p < 0.05) in 70F group. It was concluded that BIRG based diet with a high forage level had no adverse effects on rumen fermentation, some blood chemical parameters, and immune system in dry Holstein cows and could be used as a forage source instead of imported TF.

• Advances in concrete construction
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• 제11권5호
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• pp.419-428
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• 2021

The pH of cement-based materials (CBMs) is an important factor for their durability, sustainability, and long service life. Currently, the use of supplementary cementitious materials (SCMs) is becoming mandatory due to economic, environmental, and sustainable issues. There is a decreasing trend in pH of CBMs due to incorporation of SCMs. The determination of numerical values of pH is very important for various low and high volume SCMs blended cement mortars for the better understanding of different defects and durability issues during their service life. In addition, the effect of cement hydration and pozzolanic reaction of SCMs on the pH should be determined at initial and later ages. In this study, the effect of low and high-volume fly ash (FA) and ground granulated ballast furnace slag (GGBFS) cement mortars in different curing conditions on their pH values has been determined. Thermal gravimetric analysis (TGA) was carried out to support the findings from pH measurements. In addition, thermal conductivity (k-value) and strength activity indices of these cement mortars were discussed. The results showed that pH values of all blended cement mortars were less than ordinary Portland cement (OPC) mortar in all curing conditions used. There was a decreasing tendency in pH of all mortars with passage of time. In addition, the pH of cement mortars was not only dependent on the quantity of Ca(OH)₂. The effect of adding SCMs on the pH value of cement mortar should be monitored and measured for both short and long terms.

• Korea-Australia Rheology Journal
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• 제16권4호
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• pp.175-182
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• 2004

Colloidal coating solution was prepared to enhance the hydrophilic property of the film surface. Water and ethanol were used as the dispersion media and (glycidoxypropyl) trimethoxysilane (GPS) as a binder in the colloidal silica coatings. Ethylene diamine was added to the colloidal silica solution as the curing agent. The colloidal silica solution was regarded as a hard-sphere suspension model with low volume fraction of the silica particles. Rheological properties of the silica suspensions modified with GPS have been investigated as a function of pH and concentration. The acidic solution showed high viscosity change by fast hydrolysis reaction and adsorption of the organic binders on the surface of silica particles. However, the hydrolysis was slow at the basic condition and the binders combined with themselves by condensation. The viscosity change was smallest at pH 7. The viscosity increased with the curing time after adding ethylenediamine, and the increase of viscosity at low pH was higher than that at high pH. The hydrophilic properties of the coating film were investigated by the contact angle of water and film surface. The smallest contact angle was shown under the strong acidic condition of pH 2.

• 한국가금학회지
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• 제34권3호
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• pp.217-222
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• 2007

본 연구는 육계 사료 내 조단백질 수준에 따른 갯벌 미생물 유래 단백질 분해효소제를 첨가하였을 때 생산성, 영양소 소화율 및 혈액 내 total protein과 BUN 함량에 미치는 영향을 알아보기 위해 실시하였다. 사양 시험은 2일령 Arbor Acres 육계(male) 480수를 공시하여 5주간 실시하였다. 시험 설계는 기초 사료 내 조단백질 함량과 효소제의 첨가 유무에 따라 high crude protein diet 처리구, high crude protein diet에 단백질 분해 효소제를 첨가한 처리구(high crude protein diet+0.1% protease), low crude protein diet 처리구 및 low crude protein diet에 단백질 분해 효소제를 첨가한 처리구(low crude protein diet+0.1% protease)로 4처리($2{\times}2$ factorial)를 하여 처리당 6반복, 반복당 20수씩 완전 임의 배치하였다. 전체 사양 시험 기간 동안, 증체량은 high crude protein diet 처리구들과 low crude protein diet에 단백질 분해 효소제를 첨가한 처리구가 low crude protein diet 처리구와 비교하여 유의적으로 높게 나타났다(P<0.05). 사료 섭취량에서는 처리구간에 유의적인 차이를 보이지 않았다. 사료 요구율에서는 high crude protein diet 처리구들과 low crude protein diet에 단백질 분해 효소제를 첨가한 처리구가 low crude protein diet 처리구와 비교하여 유의적으로 낮게 나타났다(P<0.05). 또한, 건물 소화율은 high crude protein diet 처리구들과 low crude protein diet에 단백질 분해효소제를 첨가한 처리구가 low crude protein diet 처리구와 비교하여 유의적으로 높게 나타났고(P<0.05), 질소 소화율에서는 high crude protein diet에 단백질 분해 효소제를 첨가한 처리구가 low crude protein diet 처리구와 비교하여 유의적으로 증가하였다(P<0.05). 혈액 내 total protein 함량은 high crude protein diet 처리구가 다른 처리구들과 비교하여 유의적으로 증가하였고(P<0.05), BUN 함량은 처리구들 간에 유의적인 차이를 보이지 않았다. 결론적으로, 육계 사료 내 조단백질 수준에 따른 갯벌 미생물 유래 단백질 분해효소제의 첨가는 증체량, 사료 요구율, 영양소 소화율을 개선시켰고, 혈액 내 total protein 함량에 영향을 미쳤다.

• BMB Reports
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• 제41권8호
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• pp.609-614
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• 2008

The concentrations and catalytic activities of enzymes control metabolic rates. Previous studies have focused on enzyme concentrations because there are no genome-wide techniques used for the measurement of enzyme activity. We propose a method for evaluating the significance of enzyme activity by integrating metabolic network topologies and genome-wide microarray gene expression profiles. We quantified the enzymatic activity of reactions and report the 388 significant reactions in five perturbation datasets. For the 388 enzymatic reactions, we identified 70 that were significantly regulated (P-value < 0.001). Thirty-one of these reactions were part of anaerobic metabolism, 23 were part of low-pH aerobic metabolism, 8 were part of high-pH anaerobic metabolism, 3 were part of low-pH aerobic reactions, and 5 were part of high-pH anaerobic metabolism.

• Asian-Australasian Journal of Animal Sciences
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• 제20권2호
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• pp.200-207
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• 2007

In vitro rumen incubation studies were conducted to determine effects of initial pH on bacterial attachment and fiber digestion. Ruminal fluid pH was adjusted to 5.7, 6.2 and 6.7, and three major fibrolytic bacteria attached to rice straw in the mixed culture were quantified with real-time PCR. The numbers of attached and unattached Fibrobacter succinogenes, Ruminococcus flavefaciens and Ruminocococcus albus were lower (p<0.05) at initial pH of 5.7 without significant difference between those at higher initial pH. Lowering incubation media pH to 5.7 also increased bacterial numbers detached from substrate regardless of bacterial species. Dry matter digestibility, gas accumulation and total VFA production were pH-dependent. Unlike bacterial attachment, maintaining an initial pH of 6.7 increased digestion over initial pH of 6.2. After 48 h in vitro rumen fermentation, average increases in DM digestion, gas accumulation, and total VFA production at initial pH of 6.2 and 6.7 were 2.8 and 4.4, 2.0 and 3.0, and 1.2 and 1.6 times those at initial pH of 5.7, respectively. The lag time to reach above 2% DM digestibility at low initial pH was taken more times (8 h) than at high and middle initial pH (4 h). Current data clearly indicate that ruminal pH is one of the important determinants of fiber digestion, which is modulated via the effect on bacterial attachment to fiber substrates.