• Macromolecular Research
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• v.11 no.3
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• pp.189-193
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• 2003

pH- and temperature-sensitive bifunctional hydrogels composed of N-isopropylacrylamide (NiPAAm) and a sulfadimethoxine monomer (SDM) derived from sulfadimethoxine were prepared. These hydrogels exhibit simultaneous pH- and temperature-induced volume-phase transitions. The pH-induced volume-phase transition behavior is produced by the ionization/deionization of SDM and is very sharp. In the high pH region, the ionization of SDM induces swelling of the hydrogels. In the low pH region, the deionization of SDM induces deswelling of the hydrogels. The temperature-induced volume-phase transition behavior of the bifunctional hydrogels exhibits negative thermosensitivity because of the NiPAAm component. The hydrogels swell even at low pH as the temperature decreases. The hydrogels swell at low temperature and high pH, and deswell at high temperature and low pH. The volume of the hydrogels dependl on the balance of the swelling and deswelling produced by the two competing stimuli, pH and temperature.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.3
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• pp.131-137
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• 2020

The present study investigated effects of antifungal and carboxylesterase inoculant on rumen fermentation with different rumen pH. Corn silage was treated without inoculant (CON) and with a mixed Lactobacillus brevis 5M2 and L. buchneri 6M1 (MIX). Rumen fluid was collected from two cannulated Hanwoo heifers before morning feeding (high rumen pH at 6.70) and 3 h after feeding (low rumen pH at 6.20). Dried corn silage was incubated in the rumen buffer (rumen fluid + anaerobic culture medium at 1:2 ratio) for 48 h at 39℃. Eight replications for each treatment were used along with two blanks. Both in a high and a low rumen pH, MIX silages presented higher (p<0.05) the immediately degradable fraction, the potentially degradable fraction, total degradable fraction, and total volatile fatty acid (VFA) than those of CON silages. Incubated corn silages in a low rumen pH presented lower (p<0.05) total degradable fraction, ammonia-N, total VFA (p=0.061), and other VFA profiles except acetate and propionate, than those in a high rumen pH. The present study concluded that application of antifungal and carboxylesterase inoculant on corn silage could improve degradation kinetics and fermentation indices in the rumen with high and low pH conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.12
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• pp.1751-1755
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• 2017

Objective: An experiment was conducted to study the blood haematology, muscle pH, and serum cortisol changes in pigs with different levels of drip loss. Methods: Two groups (low and high) of 20 animals were selected from 100 pigs based on drip loss. All [$Duroc{\times}(Large\;White{\times}Landrace)$] pigs were slaughtered according to standard slaughtering procedures. At exsanguinations, blood samples were taken for the haematological parameters and serum cortisol analysis. The muscle samples were taken from longissimus dorsi muscle to evaluate the muscle pH and drip loss. Results: Haematological parameters of low drip loss group showed higher content of white blood cells and monocytes than high drip loss group (p<0.05). The low drip loss group had higher muscle pH at 45 min (p<0.05) and 24 h (p<0.001) post-mortem than the high drip loss group. However, there was no significant difference in serum cortisol levels (p>0.05). Conclusion: Drip loss is mainly affected by the muscle pH decline after slaughter and also might be affected by white blood cells and monocytes.

• Journal of the Korean Applied Science and Technology
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• v.32 no.2
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• pp.202-214
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• 2015

Stimuli-responsive biomaterials that alter their function through sensing local molecular cues may enable technological advances in the fields of drug delivery, gene delivery, actuators, biosensors, and tissue engineering. In this research, pH-responsive hydrogel which is comprised of dimethylaminoethyl methacylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) was synthesized for the effective delivery of doxorubicin (Dox) to breast cancer cells. Cancer and tumor tissues show a lower extracellular pH than normal tissues. DMAEMA/HEMA hydrogels showed significant sensitivity by small pH changes and each formulation of hydrogels was examined by scanning electron microscopy, mechanical test, equilibrium mass swelling, controlled Dox release, and cytotoxicity. High swelling ratios and Dox release were obtained at low pH buffer condition, low cross-linker concentration, and high content of DMAEMA. Dox release was accelerated to 67.3% at pH 5.5 for 6-h incubation at $37^{\circ}C$, while it was limited to 13.8% at pH7.4 at the same time and temperature. Cell toxicity results to breast cancer cells indicate that pH-responsive DMAEMA/HEMA hydrogels may be used as an efficient matrix for anti-cancer drug delivery with various transporting manners. Also, pH-responsive DMAEMA/HEMA hydrogels may be useful in therapeutic treatment which is required a triggered release at low pH range such as gene delivery, ischemia, and diabetic ketoacidosis.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.152-157
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• 1991

Growth status, plant nutrition and soil chemical properties were investigated for lettuce, spring onion and red pepper grown under vinyl house near Yesan. Low Ca and Mg with high K in soil resulted in Ca deficiency with slight Mg insufficiency in Korean lettuce. In this soil pH was low and EC was extremely low. Spring onion(Allium wakegi) can not emerge or showed poor growth(50%) due to high EC(above 0.5m mho/cm) and low pH (below 6.2). Red pepper plant showed wilt disease probably due to low soil pH.

• Nuclear Engineering and Technology
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• v.43 no.5
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• pp.459-468
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• 2011

The current solution to the problem of using cementitious material for sealing purposes in a final radioactive waste repository is to develop a low-pH cement grout. In this study, the material properties of a low-pH cement grout based on a recipe used at ONKALO are investigated by considering such factors as pH variation, compressive strength, dynamic modulus, and hydraulic conductivity by using silica fume and micro-cement. From the pH measurements of the hardened cement grout, the required pH (< pH 11) is obtained after 130 days of curing. Although the engineering properties of the low-pH cement grout used in this study are inferior to those of conventional high-pH cement grout, the utilization of silica fume and micro-cement effectively meets the long-term environmental and durability requirements for cement grout in a radioactive waste repository.

• Korean Journal of Food Science and Technology
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• v.23 no.3
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• pp.286-290
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• 1991

Phytic acid known as an antinutritional facfor was studied for its effect on the solubility and digestibility of high-phytate and low-phytate soy protein isolates (SPI) obtained by two different methods of pH adjustment. Phytic acid content was 2.48% in high-phytate SPI and 0.72% in low-phytate SPI. Solubility of soy proteins was higher in low-phytate SPI than in high-phytate SPI at all pH values tested and it was lowered by adding more phytic acid to result in precipitation of the proteins. The inhibitory effect of phytic acid toward pepsin digestion of SPI increased by the increasing amount of phytic acid added and its effect was slightly higher in high-phytate SPI than in low-phytate SPI.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.539-556
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• 1995

Periodontal therapeutic modalities should be re-establishing and regenerating the periodontal tissue previously lost to the disease. To achieve periodontal regeneration, periodontal ligament cells must selective migrate to the deneded root surface, attached and proliferated it. Local pH concentration is one of the most factors that periodontal regeneration. The aims of this study were to examine on biological effects of pH to the human periodontal ligament cells in vitro, especially on the cell morphology, attachment, activity, vitality and viability. Human periodontal ligament cells were cultured from extracted tooth for non-periodontal reason. Immediately after extraction, any soft tissue adhering to the cervical parts of the roots was carefully removed with a sterile curette. To produce different pH levels in the media, Eagle's MEM was adjusted from pH 6.6 to 8.2 in 0.2 intervals with 1 M NaOH and 1 N HCl. After cultivation, Then, Periodontal ligament cells were cultured at pH ranging from 6.6-8.2. attachment assay was done at 1, 2 day incubation and activity assay was done at 1, 2, 3 day incubation. The experiments were evaluated by scaning electron microscopic techniques (HITACHIX-650 Scaning Electron Microanalyzer, Tokyo, Japan), MTT assay, and the cultured periodontal ligament cells were fixed in neutral formalin for 24 hours and immunohistochemically processed by PCNA for proliferating ability. The surviving cells in the medium showed slightly increased volume and widening intercellular distances at low concentration of pH than control group (pH 7.4), and apparently shrinkage at high concentration of pH than control group (pH 7.4). The results of the statistical analysis from the experiment on attachment, vitality and viability were as follows. Attachment of periodontal ligament cells at 1st and 2nd day, similar attachment rate of low concentration pH compared with control value (pH 7.4). But above pH 8.0, attachment rate were statistically significant decrease from control value(P<0.05). Periodontal ligament cell's activities were maximum at pH 7.6 by MTT assay. Similar with control value at low concentration of pH. But, the activities were statistically significant decrease at high concentraration of pH(P<0.05). Cellular proliferating rate (PCNA index) were statistically significant decrease from control value at low and high concentration of pH(p<0.05). This results suggested that hjgh concentration pH, in other words, alkali pH was cytotoxic effects on human periodontal ligament cells in vitro.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.7
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• pp.1038-1044
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• 2012

In the present study, the impact of Salmonella Typhimurium on cell-mediated immunity (CMI) was investigated in 5 week-old immuno divergent broiler lines selected for the high and low response to phytohemagglutinin-P. The immune response was assessed in peripheral-blood mononuclear cells (PBMCs) induced with Salmonella Typhimurium at different time intervals (0 h, 0.5 h, 2 h, 4 h, 6 h, 12 h and 24 h). The differential mRNA expression patterns of IFN-${\gamma}$, IL-2 and iNOS were evaluated by quantitative real time PCR. In-vitro production of nitric oxide (NO) was also estimated in the culture supernatant and correlated with iNOS mRNA expression. Present study showed higher production of NO in the high cell-mediated line (HCMI) as compared to the low cell-mediated line (LCMI) upon stimulation with Salmonella Typhimurium. Correspondingly, higher mRNA expression of iNOS and IFN-${\gamma}$ were observed in high response birds (HCMI); but IL-2 was down regulated in this line compared to the low response birds (LCMI). Significantly (p<0.05) higher expression of iNOS, IFN-${\gamma}$ and higher production of NO in high line indicated that the selection for PHA-P response might be employed for increasing the immune competence against Salmonella Typhimurium in chicken flocks.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.929-935
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• 2015

This study was carried out to investigate pH, EC, solutes concentration and ANC characteristics in coniferous forest experiment watershed in Gyeonggi-do, Korea from 2005 to 2007. The average pH value was 6.87 and low at spring season due to deposition in crown. The average EC was $58.4{\mu}S/cm$ and was high at spring season due to high concentration of solutes. The cation and anion concentration was high at spring and fall season with low rainfall. When stream water quality was compared to different watershed, EC was relatively low due to high rainfall and $NO_3{^-}$ was high due to deposition and forest practice. pH and ANC was relatively constant at stream water