• Title, Summary, Keyword: $CaCO_3$ preparation

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Preparation of Borosilicate Foamed Glass Body with Sound Absorption Characteristics by the Recycling Waste Liquid Crystal Display Glass (폐 LCD 유리를 이용한 흡음특성을 갖는 붕규산유리발포체 제조)

  • Lee, Chul-Tae
    • Applied Chemistry for Engineering
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    • v.27 no.6
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    • pp.612-619
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    • 2016
  • In this research, an alumino-borosilicate foamed glass with sound absorption property was prepared using the waste borosilicate glass obtained from the recycling process of waste liquid crystal display (LCD) panel. A 100 g of pulverized waste borosilicate glass with the particle size of under 325 mesh, was mixed with 0.3 g (wt/wt) of graphite, each 1.5 g (wt/wt) of $Na_2CO_3$, $Na_2SO_4$ and $CaCO_3$ as a foaming agent, and 6.0 g (wt/wt) of $H_3BO_3$ and 3.0 g (wt/wt) of $Al_2O_3$ as a pore control agent. Following mixture was under the foaming process for 20 minutes at a foaming temperature of $950^{\circ}C$. The result yielded the foaming agent with 45% of the opened porosity and 0.5-0.7 of the sound absorbing coefficient. This alumino-borosilicate foamed glass with the sound absorption property showed excellent physical and mechanical properties such as density of $0.21g/cm^3$, bending strength of $55N/cm^2$ and compression strength of $298N/cm^2$ which can be ideally used as sound absorption materials with heat-resisting and chemical-resisting property.

Effects of Adenosine on the Action Potentials of Rabbit SA Nodal Cells (동방결절 활동전압에 대한 아데노신 효과)

  • Kim, Ki-Whan;Ho, Won-Kyung
    • The Korean journal of physiology & pharmacology
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    • v.18 no.1
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    • pp.19-35
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    • 1984
  • Since the first report of Drury and $Szent-Gy{\ddot{o}}rgyi$ in 1929, the inhibitory influences of adenosine on the heart have repeatedly been described by many investigators. These studies have shown that adenosine and adenine nucleotides have overall depressant effects, similar to those of acetylcholine. Heart beats become slow and weak. It is also well known that adenosine is a potent endogenous coronary vasodilator. Many investigations on the working mechanisms of adenosine have been focused mainly on the effects of the coronary blood flow. However, the cellular mechanisms underlying the inhibitory action of adenosine on sinus node are not well understood yet. Thus, this study was undertaken to examine the behavior of rabbit SA node under influence of adenosine. In these series of experiments three kinds of preparations were used: whole atrial pair, left atrial strip, and isolated SA node preparations. The electrical activity of SA node was recorded with conventional glass microelectrodes 30 to 50 $M{\Omega}$. The preparations were superfused with bicarbonate-buffered Tyrode solution of pH 7.35 and aerated with a gas mixture of $3%\;CO_2-97%\;O_2$ at $35^{\circ}C$. In whole atrial pair, adenosine suppressed sinoatrial rhythm in a dose-dependent manner. Effect of adenosine on atrial rate appeared at the concentration of $10^{-5}M$ and was enhanced in parallel with the increase in adenosine concentration. Inhibitory action of adenosine on pacemaker activity was more prominent in the preparation pretreated with norepinephrine, which can steepen the slope of pacemaker potential by increasing permeability of $Ca^{+2}$. Calcium ions in perfusate slowly produced a marked change in sinoatrial rhythm. Elevation of the calcium concentration from 0.3 to 8 mM increased the atrial rate from 132 to 174 beats/min, but over 10 mM $Ca^{+2}$ decreased. The inhibitory effect of adenosine on sinoatrial rhythm developed very rapidly. Atrial rate was recovered promptly from the adenosine-induced suppression by the addition of norepinephrine, but extra $Ca^{+2}$ was less suitable to restore the suppression of atrial rate. Adenosine suppressed also atrial contractility in the same dosage range that restricted pacemaker activity, even in the reserpinized preparation. In isolated SA node preparation, spontaneous firing rate of SA node at $35^{\circ}C$(mean{\pm}SEM, n=16) was $154{\pm}3.3\;beats/min. The parameters of action potentials were: maximum diastolic potential(MDP), $-73{\pm}1.7\;mV: overshoot(OS), $9{\pm}1.4\;mV: slope of pacemaker potential(SPP), $94{\pm}3.0\;mV/sec. Adenosine suppressed the firing rate of SA node in a dose-dependent manner. This inhibitory effect appeared at the concentration of $10^{-6}M$ and was in parallel with the increase in adenosine concentration. Changes in action potential by adenosine were dose-dependent increase of MDP and decrease of SPP until $10^{-4}M$. Above this concentration, however, the amplitude of action potential decreased markedly due to the simultaneous decrease of both MDP and OS. All these effects of adenosine were not affected by pretreatment of atropine and propranolol. Lowering extra $Ca^{2+}$ irom 2 mM to 0.3 mM resulted in a marked decrease of OS and SPP, but almost no change of MDP. However, increase of perfusate $Ca^{2+}$ from 2 mM to 6 or 8 mM produced a prominent decrease of MDP and a slight increase of OS and SPP. Dipyridamole(DPM), which is known to block the adenosine transport across the cell membrane, definately potentiated the action of adenosine. The results of this experiment suggest that adenosine suppressed pacemaker activity and atrial contractility simultaneously and directly, by decreasing $Ca^{2+}-permeability$ of nodal and atrial cell membranes.

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The Effects of Low Calorie Meal and Weight Control Preparation on the Reduction of Body Weight and Visceral Fat in Obese Females (비만여성에서 저열량식사와 체중감량제 섭취에 의한 체중 및 체지방 감소 효과)

  • Park, Sun-Mi;Han, Dae-Seok;Kim, Dong-Woo;Lee, Sun-Yung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.9
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    • pp.1492-1500
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    • 2004
  • The purpose of this study was to evaluate the effects of low calorie meal substitute and weight control preparation containing dietary fibers, ${\alpha}$-amylase inhibitor and hydroxycitrate on the reduction of body weight and visceral fat in obese women. Sixteen pre-menoposal healthy women (age: 20∼50 y, body mass index >25) who were living in the Daejeon area participated in this study. We replaced one meal of the subject with low calorie meal substitute and fed the weight control preparation twice a day for 9 weeks. Anthropometric indices, body composition, dietary intake and stool movements were investigated every 3 weeks during the dietary intervention. The blood was collected before and after the dietary intervention. Results are as follows: 1) The subjects' body weight, body fat, BMI, waist, hip and abdominal adipose tissue decreased gradually and significantly between 3rd and 9th week after intervention. 2) The levels of fasting blood glucose, triglyceride and cholesterol, the indicators of liver dysfunction such as activities of ALT, AST and ALP, and bilirubin level were within a normal range and not affected significantly by dietary intervention. 3) Hemoglobin levels increased significantly and blood urea nitrogen level decreased. 4) Their stool movement was improved 5) Compared with the baseline values, calorie intake decreased by 17.5∼21.9% and the intakes of vitamin A, vitamin B2, folate, Ca, Fe, and Zn were below 80% of Korean RDA. In conclusion, the intake of low calorie meal substitute and weight control preparation could be effective in reduction of body weight and fat mass, improving the stool movement and the general physical symptoms.

Preparation of Self-repairing Polymer-modified Waterproofing Asphalt-montmorillonite Composite: 1. Silylation Characteristics of Montmorillonite (K-10) Using 3-aminopropyltriethoxysilane and its Optimal Condition According to a Criterion by XRD Analysis (자가치유성을 갖는 고분자개질 방수아스팔트-몬모릴로나이트 composite 제조: 1. 3-aminopropyltriethoxysilane에 의한 몬모릴로나이트(K-10)의 실란화 특성 및 XRD 분석의 기준에 따른 최적화)

  • Lee, Eun Ju;Lee, Jong Hoon;Park, You Jin;Yoon, Yong Keun;Lim, Kwang-Hee
    • Korean Chemical Engineering Research
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    • v.55 no.3
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    • pp.401-408
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    • 2017
  • In preparation of self-repairing polymer-modified waterproofing asphalt-montmorillonite (MMT) composite, silylation-modification characteristics of cation ($Na^+$) exchanged K-10 (Na-MMT-K) using 3-aminopropyltriethoxysilane (APS) were studied and the optimal conditions of its silylation-modification process were proposed by use of the results of XRD analysis on silylation-modified Na-MMT-K (S-Na-MMT-K) under various conditions. According to XRD results, it was confirmed that peaks of Na-MMT-K were simultaneously consistent with those of K-10 and natural or Ca-MMT modified Na-MMT. Similarly, S-Na-MMT-K was observed to have two basal spacings ($d_{001}$), among which the area-ratio of a secondary (001) peak ($2{\theta}=3.9{\sim}4.2^{\circ}$) to a primary (001) peak ($2{\theta}{\sim}8.838^{\circ}$) was suggested to be a criterion to represent a degree of APS silylation-modification. Then, the optimal conditions on APS-stirring period prior to APS-MMT reaction, APS-MMT reaction period, APS concentration and reaction temperature at the highest area-ratio were turned out to be 20 min, 2~3 hr, 7.5 w/v% and $50^{\circ}C$, respectively.

Relation of Ethanol and Calcium to Contractile and Electrical Activity of Cat Stomach (고양이 위(胃)의 수축 및 전기활동에 대한 에탄올과 칼슘의 관계)

  • Kim, Myung-Suk;Sim, Sang-Soo;Yoon, Shin-Hee;Han, Sang-Jun;Kim, Chung-Chin;Choi, Hyun
    • The Korean journal of physiology & pharmacology
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    • v.21 no.2
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    • pp.259-272
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    • 1987
  • This was study carried out to investigate the effect of calcium on spontaneous contraction and electrical activity induced by ethanol in gastric smooth muscle. After peeling off the mucous membrane from the isolated whole stomach of 102 cats, two kinds of small muscle preparations $(2.0{\times}0.2\;cm)$, one longitudinal and the other circular, were excised from the fundus, the corpus and the antrum portion of each whole stomach specimen. The isometric contraction of the small muscle preparation was measured in a cylinder-shaped chamber filled with Krebs-Ringer-dextrose solution (pH 7.4, temperature $36{\pm}0.5^{\circ}C$) bubbling with 5% $CO_2$ in $O_2$. A large muscle preparation $(5.0{\times}1.2\;cm)$ was excised from the anterior wall of the corpus-antrum portion of the same specimen in 72 of 102 cats. The gastric electrical activity (slow wave and spike potential) was monopolarly recorded by four capillary electrodes (Ag-AgCl), of which two were placed on the corpus and two on the antrum, in a muscle chamber filled with the same solution as described above. Changes in the amplitude of the contraction, frequency of the gastric slow wave and the production of the spike potential were observed after adding ethanol and/or under the treatments with verapamil, $CaCl_2$ and Ca-free Krebs-Ringer-dextrose solution. The results were as follows: 1) After adding ethanol, the spontaneous phasic contraction of the corpus was reduced dose-dependently (0.125-2.0%), which was totally abolished by higher concentrations (2.0-8.0%) of ethanol. 2) The corporal phasic contraction was also completely abolished by verapamil $(3{\times}10^{-5}\;M)$ or Ca-free Krebs-Ringer-dextrose solution. The contraction was increased by $CaCl_2\;(1.8{\times}10^{-3}\;M)$, but the inhibitory effect of ethanol on the contraction persisted even under the treatment with $CaCl_2$. 3) At higher concentrations, ethanol caused tonic contraction of both preparations from the fundus, the corpus and the antrum in a dose-dependent manner. The tonic contraction of the fundus produced by ethanol was not influenced by $CaCl_2$ or verapamil, whereas the tonic contraction was not produced by ethanol in tile Ca-free solution. 4) Frequency of gastric slow wave was decreased dose-dependently by the addition of ethanol (0.25-1.0%), and tile slow wave was not produced by higher concentration of ethanol (2.0%). 5) The frequency of slow wave was significantly reduced by verapamil only and the inhibitory influence of ethanol on the slow wave frequency was reinforced by verapamil. 6) The treatment of $CaCl_2$ increased significantly the slow wave frequency, and attenuated the inhibitory effect of ethanol on the frequency. It is therefore suggested that ethanol regulates the phasic contraction and the production of slow wave by interfering with the transport of calcium in the stomach muscle of the cat.

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Preparation and Characterization of Homogeneous Hydroxyapatite Sphere (균일한 Hydroxyapatite Sphere 제조 및 특성분석)

  • Lee, Kang Huk;Shin, Dong Geun;Kwon, Woo Teck;Kim, Hyungsun;Kim, Hee Rae;Kim, Younghee;Kim, Soo Ryong
    • Journal of the Korean Ceramic Society
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    • v.51 no.3
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    • pp.145-149
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    • 2014
  • A hydroxyapatite microsphere was prepared using a spray-drying method. The change in the shape as a function of the slurry concentration and the change in the degree of shrinkage according to the heat-treatment temperatures were observed. To obtain biomaterials with improved bio-stability, $CaHPO_4{\cdot}2H_2O$ and $Ca(OH)_2$ were mixed at a ratio of 6 : 4 and then ball-milled to synthesize hydroxyapatite. The hydroxyapatite microsphere was prepared using 30 wt% ~ 80 wt% hydroxyapatite slurry by a spray-drying method. For concentrations lower than 50 wt% or higher than 80 wt%, doughnut-shaped microspheres were produced. However, perfect microspheres were produced when using slurry concentrations of 50 wt% ~ 70 wt%. A dense microstructure was observed after a heat treatment at temperatures higher than $1100^{\circ}C$ and the size was reduced by 24.3% at these temperatures.

Preparation of Pure CO2 Standard Gas from Calcium Carbonate for Stable Isotope Analysis (탄산칼슘을 이용한 이산화탄소 안정동위원소 표준시료 제작에 대한 연구)

  • Park, Mi-Kyung;Park, Sunyoung;Kang, Dong-Jin;Li, Shanlan;Kim, Jae-Yeon;Jo, Chun Ok;Kim, Jooil;Kim, Kyung-Ryul
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.18 no.1
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    • pp.40-46
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    • 2013
  • The isotope ratios of $^{13}C/^{12}C$ and $^{18}O/^{16}O$ for a sample in a mass spectrometer are measured relative to those of a pure $CO_2$ reference gas (i.e., laboratory working standard). Thus, the calibration of a laboratory working standard gas to the international isotope scales (Pee Dee Belemnite (PDB) for ${\delta}^{13}C$ and Vienna Standard Mean Ocean Water (V-SMOW) for ${\delta}^{18}O$) is essential for comparisons between data sets obtained by other groups on other mass spectrometers. However, one often finds difficulties in getting well-calibrated standard gases, because of their production time and high price. Additional difficulty is that fractionation processes can occur inside the gas cylinder most likely due to pressure drop in long-term use. Therefore, studies on laboratory production of pure $CO_2$ isotope standard gas from stable solid calcium carbonate standard materials, have been performed. For this study, we propose a method to extract pure $CO_2$ gas without isotope fractionation from a solid calcium carbonate material. The method is similar to that suggested by Coplen et al., (1983), but is better optimized particularly to make a large amount of pure $CO_2$ gas from calcium carbonate material. The $CaCO_3$ releases $CO_2$ in reaction with 100% pure phosphoric acid at $25^{\circ}C$ in a custom designed, evacuated reaction vessel. Here we introduce optimal procedure, reaction conditions, and samples/reactants size for calcium carbonate-phosphoric acid reaction and also provide the details for extracting, purifying and collecting $CO_2$ gas out of the reaction vessel. The measurements for ${\delta}^{18}O$ and ${\delta}^{13}C$ of $CO_2$ were performed at Seoul National University using a stable isotope ratio mass spectrometer (VG Isotech, SIRA Series II) operated in dual-inlet mode. The entire analysis precisions for ${\delta}^{18}O$ and ${\delta}^{13}C$ were evaluated based on the standard deviations of multiple measurements on 15 separate samples of purified $CO_2$. The pure $CO_2$ samples were taken from 100-mg aliquots of a solid calcium carbonate (Solenhofen-ori $CaCO_3$) during 8-day experimental period. The multiple measurements yielded the $1{\sigma}$ precisions of ${\pm}0.01$‰ for ${\delta}^{13}C$ and ${\pm}0.05$‰ for ${\delta}^{18}O$, comparable to the internal instrumental precisions of SIRA. Therefore, we conclude the method proposed in this study can serve as a way to produce an accurate secondary and/or laboratory $CO_2$ standard gas. We hope this study helps resolve difficulties in placing a laboratory working standard onto the international isotope scales and does make accurate comparisons with other data sets from other groups.

The Preparation and Properties of Petroleum Sulfonate Dispersant (열분해 잔유를 원료로 한 분산제의 제조 및 특성)

  • Choi, Sang-Won;Kim, Eun-Young;Chang, Woo-Seok;Kim, Viktor;Moon, Jang-Soo
    • Applied Chemistry for Engineering
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    • v.18 no.5
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    • pp.490-494
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    • 2007
  • Dispersants were prepared from petroleum pyrolysis residual oil (PPRO) through sulfonation. Without employing a conventional polynaphthalene sulfonate formaldehyde condensate (PNS) process, the dispersants (NPS) were synthesized by a simpler process only in 2 h. The chemical structure of new dispersant, which has various naphthalene derivative groups, was similar to PNS conformed by UV-visible spectroscopy curves. The new dispersants demonstrated high dispersing ability in inorganic suspension ; cement, $Fe_2O_3$, and $CaCO_3$.

Preparation of Functional Textiles by Multilayer Structure - Cotton Fabrics Treated with Chitosan and Alginate Skin - (다층 코팅 처리에 의한 기능성 섬유의 제조 - 키토산과 알지네이트로 피복된 면 -)

  • Son, Tae-Won;Lee, Ju-Hyun;Lee, Min-Gyeong;Cho, Jin-Won
    • Textile Coloration and Finishing
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    • v.23 no.3
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    • pp.201-209
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    • 2011
  • With a new method of applying chitosan and alginate onto cellulose, multi-coated cotton fabrics with chitosan and alginate were prepared and characterized. To coat cotton with chitosan, raw cotton was dipped in chitosan solution, mangled of 1kgf/$cm^2$, neutralized in 2 wt% NaOH soluton, washed, and dried at $60^{\circ}C$ oven. The chitosan-coated fiber was dipped in sodium alginate solution, 1kgf/$cm^2$ mangled, neutralized in 2 wt% $CaCl_2$ solution, washed, and dried at $60^{\circ}C$ oven, resulting in CCAC(coated cotton with chitosan and calcium alginate skin) fiber characteristics. Excellent absorbancy of distilled water and saline solution was observed by the absorption test on cotton fabric treated with CCAC(0.5 wt% calcium alginate) and 0.5 wt% calcium alginate respectively. The SEM photograph confirmed the uniform coating on the cotton fabric surface.

The Suppressive Effect of Pueraria lobata Root Extract and Its Biotransformed Preparation against Skin Wrinkle Formation

  • Koo, Hyun Jung;Lee, SungRyul;Kang, Se Chan;Kwon, Jung Eun;Lee, Da Eun;Choung, Eui-Su;Lee, Jong-Sub;Lee, Jin Woo;Park, Yuna;Sim, Dong Soo;Sohn, Eun-Hwa
    • Korean Journal of Plant Resources
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    • v.30 no.3
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    • pp.272-279
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    • 2017
  • EP was obtained through 20% ethanol extraction of Pueraria lobata root, and the fermented form of EP, FEP, was prepared from the EP after incubating with Lactobacillus rhamnosus vitaP1. There was no significant toxicity by EP and FEP up to $1000{\mu}g/ml$ in NIH-3T3, HaCaT, and B16F10 cells. In addition to antioxidant potentials of EP and FEP determined by DPPH and ABST assays, we confirmed increase of procollagen type I and elastin synthesis by supplementation of the EP and FEP at the concentration of $50{\mu}g/ml$ using ELISA kits. The protein expression levels of matrix metalloprotease (MMP)-1, -3, and -9, those are involved in the degradation of collagen or other skin matrix proteins, were remarkably suppressed while their inhibitory protein metallopeptidase inhibitor 1 (TIMP-1) was greatly up-regulated by supplementation of the EP and FEP at a concentration of $50{\mu}g/ml$. Taken together, both EP and FEP supplementation could be involved in the suppression of the skin wrinkle formation through inhibiting degradation of collagen and stimulating the synthesis of collagen and elastin. The results showed that the anti-wrinkle potential of the EP and FEP will be a promising candidate for developing cosmeceutical compounds or products.