• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.623-630
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• 1999

Decreased cardiac contractility occurs in endotoxicosis, but little is known about the ionic mechanism responsible for myocardial dysfunction. In this study, we examined the changes in $Ca{2+}$ and $K^+$ currents in cardiac myocytes from endotoxin-treated rat. Ventricular myocytes were isolated from normal and endotoxemic rats (ex vivo), that were treated for 10 hours with Salmonella enteritidis lipopolysaccharides (LPS; 1.5 mg/kg) intravenously. Normal cardiac myocytes were also incubated for 6 hours with 200 ng/ml LPS (in vitro). L-type $Ca{2+}$ current $(I_{Ca,L})$ and transient outward $K^+$ current $(I_{to})$ were measured using whole cell patch clamp techniques. Peak $I_{Ca,L}$ was reduced in endotoxemic myocytes (ex vivo; 6.00.4 pA/pF, P＜0.01) compared to normal myocytes (control; 10.90.6 pA/pF). Exposure to endotoxin in vitro also attenuated $I_{Ca,L}$ (8.40.4 pA/pF, P＜0.01). The amplitude of $(I_{to})$ on depolarization to 60 mV was reduced in endotoxin treated myocytes (16.51.5 pA/pF, P＜0.01, ex vivo; 20.00.9 pA/pF, P＜0.01 , in vitro) compared to normal myocytes (control; 24.71.0 pA/pF). There was no voltage shift in steady-state inactivation of $I_{Ca,L}$ and $(I_{to})$ between groups. These results suggest that endotoxin reduces $Ca{2+}$ and $K^+$ currents of rat cardiac myocytes, which may lead to cardiac dysfunction.

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.337-340
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• 1999

Luminescence of bismuth activated CaS, CaS:Bi, prepared in sodium polysulfide is studied. Excitation spectrum of CaS:Bi shows a band at 350 nm due to the recombination process between holes in Na+Ca2+ and electrons in conduction bands, in addition to bands at 260 nm from band gap of CaS, and at 320 nm (1S0→1P1) and at 420 nm (1S0→3P1) from electronic energy transitions of Bi. Emission band at 450 nm is from 3P1→1S0 transition of Bi3+, bands at 500 nm and 580 nm correspond to recombinations of electron donors (Bi3+Ca2+ and VS2-) with acceptors (VCa2+ and Na+Ca2+). Emission band of 3P1→1S0 transition is shifted to longer wavelength from CaS:Bi to BaS:Bi, due to the increase of the Stokes shift by the decrease of the crystal field parameter from CaS:Bi to BaS:Bi.

• Journal of Nutrition and Health
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• v.26 no.2
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• pp.145-155
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• 1993

A factorial experiment was conducted to determine the influence of phytate(0 or 10g/kg diet) and calcium (Ca)(3 or 10g/kg diet) intakes on Ca, P and Zn metabolism by growing female rats. Food intake and weight were similar for the all groups, however, phytate ingestion for six weeks depressed femur growth. The low Ca plus phytate group showed the lowest Ca content of total femur and this was related to a significant decrease of Ca retention. Phytate intake depressed zinc(Zn) absorption in the first metabolic collection. This inhibitory effect of phytate on Zn absorption was improved in the low Ca plus phytate group after several weeks. Impared Zn absorption however remained in the high Ca plus phytate group which was reflected in the lowest Zn content of femur, phytate intake with high Ca also depressed phosphorous(P) absorption and serum and urinary P. These adverse effects of phytate on Zn and P absorption when the dietary Ca was high could explain reduced femur weight despite the highest concentration of femur Ca(mg/g ash) in this group. Results suggest that phytate can adversely affect not only Ca metabolism but Zn and P utilization. Thus, for the normal bone growth when phytate intake is high, the ingesion of Ca, P, Zn and other minerals should be enhanced.

• Journal of Nutrition and Health
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• v.31 no.1
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• pp.36-45
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• 1998

Dietary and other factors affecting bone density of 32 Korean healthy college women aged 19-23 years were assessed. Data for food and nutrient intake was obtained by a semiquantitiative food frequency questionnaire. Serum samples were anlayzed for total Ca, P, Ca++, PTH, calcitonin and 25-hydroxycholecalciferol , (25-OH-Vit D3) and BMDs of lumbar spine(L2-L4), femoral neck(FN), ward's triangle (WT) and trochanter(TR) were measured by an XR-series X-ray bone densitometer. Relationships between the factors and BMDs were analyzed by stepwise multiple regression analysis and Pearson's correlation coefficient(r). The results are summarized as follows. Mean daily intake of energy(86.1%), Ca(74.3%), vitamin A (53.75), Fe(49.75) and vitamin B$_2$(86.6%) were lower while other notrients incuding P(126%) were higher than the Korean RDA. The BMDs of lumbar spines and femurs ranged from 0.73g/$\textrm{cm}^2$ to 1.23g/$\textrm{cm}^2$and 0.48g/$\textrm{cm}^2$ to 1.04g/$\textrm{cm}^2$, respectively. Both protein and P intakes were inversely associated with serum total Ca. Furthermore, Ca intake as well as Ca/P ratio (Ca/P) were inversely associated with serum ionized Ca(Ca++) concentration. The intakes of protein P and Ca , however, were not significantly associated with the BMDs measured in this study. There were little association between BMDs and alcoholic beverage or caffeine consumption. The only significant association detected was a positive relationship between caffeine consumption and BMD of WT. It seemed to be noticeable that BMDs of L2-L$_4$, FN and WT were significantly inversely associated with serum P concentration. However, there was no significant association between BMDs and the levels of total Ca to Ca++ in serum. Body weight was positively associated with BMD of lumbar spine and BMI was also positively associated with BMDs of FN and WT. The subjects who had an early menarche appeared to have higher BMDs than those who had had a late mearche. According to stepwise multiple regression analysis. Menarche and BMI were stronger determinants of BMDs in the young women than was diet. P intake appeared to be a more potent dietary determinant than Ca intake. The three factors, menarche, BMI , and P intake , additionally accounted for 24% and 378% of the variance in BMDs of FN and L$_2$-L$_4$, respectively. Further investigation is necessary to determine the factors needed to increase serum P level which negatively affects. BMD in young Korean college women.

• Journal of the Korean Ceramic Society
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• v.26 no.1
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• pp.123-131
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• 1989

Hydroxyapatite powders were syntehsized by the reaction of Ca(NO3)2.4H2O and (NH4)2HPO4 in aqueous solution. The effect of the Ca/P mole ratio in the starting solution on the sintering of the powders and its microstructure was studied. When the Ca/P mole ratio in the starting solution was 1.69, the relative density of the sintered bodies was more than 95%. The sinterability was decreased as the Ca/P mole ratio in the starting solution was increased (Ca/P mole ratio >1.67). Hydroxyapatite sintered bodies obtained from the Ca/P mole ratio=1.69 had very excellent bending strength. The best bending strength was obtained at 110$0^{\circ}C$ and its value was 1220kg/$\textrm{cm}^2$. The average grain size was 0.277${\mu}{\textrm}{m}$. Most of sintered bodies were almost shown 100% hydroxyapatite phase. However, in case of the Ca/P mole ratio=1.64 hydroxyapatite was decomposed to $\alpha$-whitlockite above 120$0^{\circ}C$.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.923-928
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• 2012

Optimizing a water-phase suspending system is very important to manufacture high-quality suspension polymerized toners. Therefore, in this study, the effects of the molar ratio of calcium hydroxide ($CaOH_2$)/phosphoric acid ($H_3PO_4$)(Ca/P), which were used as inorganic suspending agents, and pH of the water-phase on the characteristics of styrene-based suspension polymerized toners were mainly investigated. At first, the water-phase was fixed to neutral condition (pH=7.5) and Ca/P molar ratio was changed from 1.5:1 to 1.76:1. As a result, an ideal calcium phosphate (hydroxyapatite) was prepared at the Ca/P molar ratio of 1.73:1 and polymerized toners prepared at this condition showed good particle size distribution, circularity and charging characteristic. Based on this result, Ca/P molar ratio was fixed to 1.73:1 and pH of the water-phase was changed to weak acidic (pH=5.5) and weak basic (pH=9.5) conditions. As a result, polymerized toners prepared under the weak acidic condition showed very good particle size distribution, circularity and charging characteristic along with excellent printing quality. High-quality suspension polymerized toners could be prepared via optimizing Ca/P molar ratio and pH of the water-phase.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.2
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• pp.93-100
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• 2010

The calcium to phosphate ratio (Ca/P) in biphasic calcium phosphates powders using X-ray diffraction analysis (XRD) was characterized. The BCP powders with various stoichiometric Ca/P molar ratio were synthesized with coprecipitation process and calcination. Compositions of the powders with Ca/P molar ratio between 1.5 and 1.67 were subjected to starting Ca/P molar ratio, pH = 10, and thermal treatment up to $900^{\circ}C$. The structural, morphological and chemical characterizations for BCP powders with stoichiometric Ca/P ratio were carried out with scanning electron microscope (SEM) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) and a phase quantification was investigated by XRD. The solubility of HAp, $\beta$-TCP, and BCP powders was tested in the phosphate buffer solution (PBS) at $36.5^{\circ}C$ and pH = 7.4.

• KSBB Journal
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• v.13 no.4
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• pp.399-403
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• 1998

This study was carried out to optimize the concentration of Ca2+ and pH of fusion medium which affected electrofusion frequency of protoplasts isolated from Nicotiana tabacum L. (cv. BY4) mesophyll cells and callus. The protoplasts were electrofused in the fusion media containing two different Ca2+ concentrations and three different pH regions. Fusion frequency was lower in the fusion medium containing only 13% mannitol as osmotic stabilizer. However, higher degree of fusion frequency (47.3%) was observed in the fusion medium containing 50mM CaCl2 at pH 10.5 than any other conditions. Cell viability was decreased by Ca2+ and high pH treatment in the fusion media, while fusion frequency was increased. It is concluded that Ca2+ is involved in electrofusion of protoplasts.

• The Korean Journal of Pain
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• v.36 no.1
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• pp.137-246
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• 2023

Background: To investigate the relationship between cutaneous allodynia (CA) and kinesiophobia, gastrointestinal system (GIS) symptom severity, physical activity, and disability, and to determine whether CA, pain, and disability were influencing factors for kinesiophobia, GIS symptoms, and physical activity in individuals with migraine. Methods: The study included 144 individuals with migraine. CA, kinesiophobia, GIS symptoms, physical activity level, and migraine-related disability were evaluated with the Allodynia Symptom Checklist, the Tampa Kinesiophobia Scale (TKS), the Gastrointestinal Symptom Rating Scale (GSRS), the International Physical Activity Questionnaire-7, and the Migraine Disability Assessment Scale (MIDAS), respectively. Results: The CA severity was only associated with TKS (r = 0.515; P < 0.001), GSRS-total (r = 0.336; P < 0.001), GSRS-abdominal pain (r = 0.323; P < 0.001), GSRS-indigestion (r = 0.257; P = 0.002), GSRS-constipation (r = 0.371; P < 0.001), and MIDAS scores (r = 0.178; P = 0.033). Attack frequency (P = 0.015), attack duration (P = 0.035) and presence of CA (P < 0.001) were risk factors for kinesiophobia. Attack frequency (P = 0.027) and presence of CA (P = 0.004) were risk factors for GIS symptoms. Conclusions: There was a relationship between the CA and kinesiophobia, GIS symptoms, and disability. CA and attack frequency were found to be risk factors for kinesiophobia and GIS symptoms. Migraine patients with CA should be assessed in terms of kinesiophobia, GIS, and disability. Lifestyle changes such as exercise and dietary changes and/or pharmacological treatment options for CA may increase success in migraine management.

• Journal of environmental and Sanitary engineering
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• v.5 no.1
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• pp.28-33
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• 1990

The turnover rates of nitrogen(N), phosphorus(P), calcium(Ca), potassium(K), and sodium(Na) during the decomposition of litter were studied in the Pinus koraiensis forest in Choon Chun and in the Pinus rigida forest in Mt. Gwanak, Seoul. The turnover rates of N, P, K, Ca, and Na were 0.064, 0.068, 0.040, 0.417, and 0.058 for the P. korai ensis litter and 0.049, 0.049, 0.023, 0.346, and 0.058 for the P. rigida litter respectively. The loss of elements follows the order Ca>P>N>Na>K in the P. koraiensis litter and the order Ca>Na>N=P>K in the P. rigida litter. Generally the turnover rates of cations were greater than those of anions.