• KSBB Journal
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• v.13 no.5
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• pp.585-592
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• 1998

The effect of intracellular Ca2+ level on the hybridoma cell growth and monoclonal antibody(MAb) production was examined. For the manipulation of intracellular Ca2+ concentration, the cells were treated with A23187, ryanodine, and thapsigargin at about 1x106 cells/mL. The treated cells were recultivated by using the Iscove's Modified Dulbecco's Medium(MDM) containing 1.49mM CaCl2. The ryanodine-treated cells showed better cell growth, MAb concentration, and specific MAb productivity than others. In comparison with control, the maximum cell concentration, MAb concentration, and specific MAb productivity were increased by 40.6%, 48.1% and 83.3%, respectively. Confocal microscopic images of Fura-2/AM loaded cells indicate that the increase in intracellular Ca2+ level can enhance the MAb productivity by allowing the calcium influx into the endoplasmic reticulumn.

• Journal of Nutrition and Health
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• v.28 no.9
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• pp.817-824
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• 1995

This study was performed to evaluate the effect of dietary protein level on Ca efficiency in bone mineral density in growing male rats. Twenty male rate were divided into two groups. The rats in one group were fed on casein 20% diet as control group and the others were fed on casein 40% diet as protein group. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. The total body, spine and femur bone mineral density and bone mineral content were measured using dual energy-x ray absorptiometry. Urinary calcium, phosphate, pyridinoline and creatinine, serum calcium, phosphate, total protein, albumin, alkaline phosphatase(ALP) and osteocalcin were measured. Urinary Ca excretion, pyridinoline and crosslinks value and serum ALP content seem to be increased in high protein group. It appears that the growing rats in high protein group had a higher bone resprption and bone formation than those in control group. Animal fad a high protein diet had a siginficantly higher Ca efficiency in BMD, BMC of total body, spine and femur. The results of this show that increasing of dietary protein level (40%) is beneficial of improvement of Ca efficiency during growing period.

• Biomedical Science Letters
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• v.12 no.1
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• pp.9-16
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• 2006

We investigated the effects of 835-MHz electromagnetic field (EMF), one of the most popular communication frequency band in Korean code-division multiple-access (CDMA) mobile phone system, on cellular signal transduction. For this, we examined the change of intracellular calcium $([Ca^{2+}]_i)$, reactive oxygen species (ROS) and F-actin polymerization after exposure to 835-MHz EMF followed by the treatment of agonists in Rat-2 fibroblast cells. Culture cells were pretreated with serum-tree medium and concomitantly exposed to 835-MHz at specific absorption rate (SAR) of 4.0 W/kg for 24 hr in a specialized designed apparatus based on Transverse Electro Magnetics (TEM) wave theory. Intracellular $Ca^{2+}$ responses to lysophosphatidic acid (LPA) and epidermal growth factor (EGF) in Rat-2 fibroblast after exposure to 835-MHz EMF were shown to be similar pattern as observed in normal cultured cells. However, the LPA-induced calcium spiking was slightly delayed to 7 sec and sustained thereafter to a little higher ground level under 835-MHz EMF radiation compared to unexposed cells. ROS production level by LPA in the exposed cells was not different from that in control. Furthermore, LPA induced the production of stress fibers with no significant difference in the exposed and unexposed cells. These results suggest that mobile phone radiation (835-MHz, SAR 4.0 W/kg) may not be directly related to signal transduction in Rat-2 fibroblasts except the slight effect of calcium spiking in LPA-induced cells but remain to be further elucidated for possible indirect intervention.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.1
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• pp.7-12
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• 1997

This study was intended to investigate the proper shape and size of calcium carbonate for the improvement of paper properties and its end use performance. We loaded calcium carbonate of various shapes and size in the handsheet and measured their physical and optical properties. Results obtained from the study are summarized as follows : 1. Due to different particle shapes and sizes, precipitated calcium carbonate (PCC) contributed greater to bulk improvement than ground calcium carbonate (GCC). Scalenohedral form of PCC produced the bulkiest sheet, GCC made the sheet bulkier as average particle size increases. 2. Tensile strength increased as average particle size was increasing. GCC kept tensile strength more effectively than PCC. The effect of particle size on tensile strength was much more pronounced as filler addition level was increasing. 3. Over the average particle size of 6.99$\mu$m, GCC gave much higher burst strength and internal bond than PCC did. In the filler levels of 20% and 30%, GCC by using bigger size fillers showed 50~100% improvement in some cases than PCC at the same filler content. 4. Tear strength increased as average particle size was increasing. At the filler level of 30%, PCC decreased tear greatly. 5. Over the average particle size of 13.56$\mu$m, GCC kept bending stiffness greater than PCC. Due to its shape, Scalenohedral form of PCC showed higher stiffness than others at the same particle size. 6. Cubic and acicular form of PCC improved light scattering coefficient very effectively. Light scattering coefficient of GCC decreased as average particle size increased. 7. Both of particle shape and size of filler were important factor in developing optical properties and bending stiffness. Particle size was the only important factor in developing other strength properties

• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.120-130
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• 1994

The purpose of the present investigation was to compare the effectiveness of porous hydroxyapatite (PHA) and coralline based porous calcium carbonate(PCC) as implant materials in human periodontal osseous defects. 10 adult patients having periodontitis and 2 similar angular osseous defects ${\ge}$5mm as verified by radiographic analysis and clinical probing depth ${\ge}$4mm were selected. The measurements were recorded just before surgery and after 6 month. Clinical parameters used in this study included gingival recession, pocket depth, probing attachment level, Sulcus Bleeding Index, Plaque Index, tooth mobility and bone defect depth measurements. After initial therapy, patients were treated with mucoperiosteal flap surgery. The contralateral bony defects in each patient randomly assigned to either bone graft material, one with PHA(Interpore 200) and the other with coralline based calcium carbonate(Biocoral). After 6 month both groups showed statistically significant reduction of pocket depth, Sulcus Bleeding Index, Plaque Index and significant improvement in probing attachment level. No statistically significant differences were found between the groups. There were 3.0mm or 68% of bone repair with PHA and 3.1mm, 61% with PCC. These values were likewise not significantly different. The data and clinical impression strongly suggest that both PHA and PCC are alloplastic implants with clinically apparent acceptance by the soft and hard tissue and that they can be used as bone graft materials successfully.

• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.41.1-41.17
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• 2023

Objectives: This scientometric and bibliometric analysis explored scientific publications related to hydraulic calcium silicate-based (HCSB) sealers used in endodontology, aiming to describe basic bibliometric indicators and analyze current research trends. Materials and Methods: A comprehensive search was conducted in Web of Science and Scopus using specific HCSB sealer and general endodontic-related terms. Basic research parameters were collected, including publication year, authorship, countries, institutions, journals, level of evidence, study design and topic of interest, title terms, author keywords, citation counts, and density. Results: In total, 498 articles published in 136 journals were retrieved for the period 2008-2023. Brazil was the leading country, and the universities of Bologna in Italy and Sao Paolo in Brazil were represented equally as leading institutions. The most frequently occurring keywords were "calcium silicate," "root canal sealer MTA-Fillapex," and "biocompatibility," while title terms such as "calcium," "sealers," "root," "canal," "silicate based," and "endodontic" occurred most often. According to the thematic map analysis, "solubility" appeared as a basic theme of concentrated research interest, and "single-cone technique" was identified as an emerging, inadequately developed theme. The co-occurrence analysis revealed 4 major clusters centered on sealers' biological and physicochemical properties, obturation techniques, retreatability, and adhesion. Conclusions: This analysis presents bibliographic features and outlines changing trends in HCSB sealer research. The research output is dominated by basic science articles scrutinizing the biological and specific physicochemical properties of commonly used HCSB sealers. Future research needs to be guided by studies with a high level of evidence that utilize innovative, sophisticated technologies.

• Toxicological Research
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• v.20 no.3
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• pp.241-250
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• 2004

We previously found that bisphenol A (BPA) caused neurotoxic behavioral alteration. Since disturbance of calcium homeostasis is an implicated contributor in the neurotoxic mechanism of environmental toxicants, we investigated whether BPA alters calcium homeostasis. Unlike other neurotoxic agents which cause increase of intracellular calcium level, BPA decreased $[Ca^{2+}]_i$ dose-dependently in PC12 cells and cortical neuronal cells regardless of the calcium existence in buffer. BPA at greater concentrations than 100 $\mu\textrm{M}$ reduced cell viability significantly in both types of cells. BPA also suppressed L-glutamate (L-type channel activator, 30 mM) and trifluoperazine (calmodulin antagonist, 30 $\mu\textrm{M}$)-induced increase of $[Ca^{2+}]_i$. BPA further lowered caffeine (RYR activator, 100 $\mu\textrm{M}$)-decreased $[Ca^{2+}]_i$, but did not alter dantrolene (RYR inhibitor, 100 $\mu\textrm{M}$), heparin (IP3 inhibitor, 200 units/ml) and xestospongin C (IP3 inhibitor, 5 $\mu\textrm{M}$)-decreased $[Ca^{2+}]_i$. Cell viability was not directly related to intracellular calcium change by bisphenol A that alternation of intracellular calcium may not be a direct causal factor of BPA-induced neuronal cell death.

• Korean Journal of Community Nutrition
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• v.11 no.4
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• pp.534-540
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• 2006

Recent studies have shown that environmental, biochemical, nutritional or genetic factors affect bone mineral density (BMD). The purpose of the present study was to investigate the effect of vitamin D receptor (VDR) gentotype and nutritional status on BMD of elderly women living in a rural area. Three hundred thirty five elderly women over 65 years in Asan participated the study. Data for demographic and nutrient intakes were obtained by survey with a two day 24 hr recall method. BMD was measured by broadband ultrasound attenuation (BUA) using quantitative ultrasound (QUS). VDR genotypes of the subjects analyzed with Bsm I restriction enzyme were bb (92%), Bb (7%) and BB (1%). No differences were found between genotypes bb and Bb/BB in age, menopausal age, body mass index and body fat. BUA of bb genotype was higher (62.5 $\pm$ 15.6 dB/MHz) than Bb/BB genotype (56.1 $\pm$ 17.6 dB/MHz) by Student's t-tests. Correlation analyses showed strong negative correlation of BMD and age, but positive correlation with BMI, energy and calcium intake. When subgroup analyses were conducted after stratification by the median calcium intake level (412.9 mg/d), the above median calcium intake group showed significant difference in BUA by VDR genotype while the lower median calcium intake group did not show significant difference. The current study confirmed interaction of calcium intake and VDR genotype in association with BMD. Further nutritional intervention will be needed to improve calcium status of the elderly women living in rural areas.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.159-163
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• 1999

Model experiments were conducted to investigate the effect of different fillers on the removal of toner ink. Combinations of different papers (commercial photocopy paper and filler-free paper), fillers (calcium carbonate, kaolin clay, and talc), and chemicals(1-octadecanol, stearic acid, oleic acid, and TOFA) and stearic acid were found to be effective in detachment and agglomeration of toner ink. Furthermore, pH had little effect on toner detachment and agglomeration, indicating both protonated fatty acids and their anions are equally effective. In the presence of either kaolin clay or talc, all these agglomerating agents are equally effective, although a slightly higher dosage(1% for clay and 2% for talc as compared with control) is required, presumably due to the adsorption of chemical by the filler. Calcium carbonate filler, on the other hand, has a significant and adverse effect on the fatty acids used but has little effect on 1-octadecanol with the exception of possible adsorption. While stearic acid is not effective, a much higher level of oleic acid or TOFA is needed when calcium carbonate fillers are present as compared to the filler-free case. Fatty acids react with calcium carbonate to form calcium salts. The availability of fatty acid anion for toner detachment and agglomeration is determined by the solubility of calcium salt of a given fatty acid. Calcium oleate is 10 times more soluble in water than calcium stearate.

• Proceedings of the Zoological Society Korea Conference
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• 1998.04a
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• pp.46.1-46
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• 1998

No Abstract, See Full Text