• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.6
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• pp.329-337
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• 2019

We synthesized potassium titanates having splinter and plate shape and evaluated frictional and wear properties of brake pad using them as reinforcements in friction materials. For splinter-shaped potassium titanates, potassium tetratitanate (K₂O·4TiO₂, PT4) with plate shape was prepared, then K ion of the titanate was leached by acid to make potassium hexatitanate (K₂O·6TiO₂, PT6), which was transformed to splinter-shaped PT6 by thermal treatment at 800℃. Plate-shaped potassium magnesium titanate (K_0.8Mg_0.4Ti_1.6O₄, PMT) was prepared by adding Mg in the potassium titanate using KCl as a flux. Using PT6 and PMT as reinforcements in friction materials of brake pad, we evaluated frictional and wear properties using 1/5-scale dynamometer. According to dynamometer test results, both reinforcements shows similar friction coefficient and fade & recovery behavior to conventional material and plate-shaped PMT exhibits higher wear resistance than splinter-shaped PT6.

• The Korean Journal of Blood Transfusion
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• v.23 no.2
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• pp.162-168
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• 2012

Background: Potassium, the most common cation in the intracellular space, plays a critical role in our physiology. Potassium imbalance may cause life-threatening problems, ranging from general weakness to cardiac arrest due to ventricular fibrillation. For emergency physicians, detection of such derangement within a short period of time is of critical importance. In this study, we wanted to determine whether analysis of whole blood samples can be used as a screening tool for potassium imbalance by comparative analysis of whole blood and serum samples. Methods: Two samples were drawn from 227 patients. The whole blood sample was taken from the radial artery and contained in a commercially available arterial blood collection syringe with a lithium-heparin coating. The serum sample was contained in a commercially available vacuum bottle in a non-additive silicone coated tube and transported to the laboratory. The study population was divided into three groups, patients with normal whole blood potassium, patients with decreased whole blood potassium, and patients with elevated whole blood potassium. Potassium levels for each group were coupled with serum potassium levels and compared. Results: No significant difference in potassium values was observed between whole blood and serum samples (P<0.05). Strong associations were observed among the three groups (normal range, hypokalemia, and hyperkalemia group). Compared to the normal group (r=0.851), the hyperkalemia group showed a stronger association between variables (r=0.897), and the hypokalemia group showed a weaker association (r=0.760). Their correlation coefficients were highly significant (P<0.05). Conclusion: Our study illustrates that point-of-care testing using whole blood with whole blood can be a reliable screening tool when treating patients with suspicious potassium abnormality, especially in hyperkalemia patients.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.3
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• pp.129-136
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• 1990

In the present report, two experiments were carried out with the purposes of knowing the differences of response among forage species to growing period and potassium level in culture solution, and investigating possible relation of the responses with occurence of grass tetany on grazing pasture. The results were as follows; (1) At 25 days after germination, fresh weight of top part as well as the sum of top and root parts of the forages increased rapidly. (2) Italian ryegrass was the highest in potassium (K) content but the lowest in magnesiurn(Mg) content among the three gramineous forages, while tall fescue showed the opposite result to it. And orchardgrass was intermediate of the two forage species (Experiment 1). (3) The K contents of forages generally increased, while Mg content became lower with the increase of K level in culture solution. The highest K contents of Italian ryegrass and orchardgrass were more than 3 times of the lowest values. The K contents of alfalfa and tall fescue increased in the narrower range. The decreases of Mg content of Italian ryegrass and orchardgrass were significant in the ranges of 5ppm to 25 or 50ppm KzO, while the content of the leguminous forages and tall fescue decreased up to 1000 level. (4) Fresh yield, water content and K content of the forages were significantly increased with the increase of K20 application levels up to 25 or 50ppm. (5) The K concentration of forage on a tissue water basis was higher at 50ppm than that at 5ppm $K_20$ level, especially for Italian ryegrass and orchardgrass with the value of 2.6times and 2.5times, respectively. However, the K concentration (tissue water) of leguminous forages increased gradually up to the level of lOOOppm (Experiment 2). It is suggested from the results that rapid changes of water content, Mg content and K concentration (tissue water) may occur to forage on a grazing pasture, when both growing period and K level in the soil affect the changes simultaneously. Under such conditions, plant water especially in Italian reyegrass and orchardgrass can function as toxic material to grazing ruminants.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.190-194
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• 2011

Potassium (K) is one of the essential nutrients for plants but is not a constituent of any plant compound. K is substances for activation of many enzymes and influences the process that the enzymes are involved in catalyzing. Although experimental results associated with the K effects with both benefits and no effects on turfgrass growth were reported, the limited research results of K effects on turfgrass among K sources are available in Korea. The objectives of the study was conducted to evaluate responses of Kentucky bluegrass (Poa pratensis L.) treated by fertilizer treatments with six K sources. There were six fertilizer treatments as K sources applied to Kentucky bluegrass which were potassium nitrate (13-0-44, PN), potassium chloride (0-0-60, PC), potassium sulfate (0-0-50, PS), polymer-coated potassium sulfate (0-0-45, PPS), potassium thiosulfate (0-0-25, PT), and potassium sulfate granulated with methylene urea (20-0-25, PSU). Potassium of $8g\;m^{-2}$ and N of $5g\;m^{-2}$ was applied 4 times giving a total 20 and $30g\;m^{-2}$, respectively. Although significant differences were found for turfgrass color, quality, chlorophyll index, and clipping dry weight, no consistent results among K sources were found during the one year study. Overall, K treatments didn't affect turfgrass growth in this study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1248-1252
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• 2012

Potassium added with bamboo salt showed better antioxidative effects than bamboo salt, solar salt, or purified salt. It also showed inhibitory effects on the mutagenicity of MNNG (N-methyl-N-nitro-N-nitrosoguanidine) in a Salmonella Typhimurium TA100 tester strain. At concentrations of 1.25 and 2.5 mg/plate, potassium bamboo salt and bamboo salt showed weaker co-mutagenicity effects than either purified salt or solar salt, respectively. Anticancer effects of salts were evaluated using MTT assay in HCT-116 human colon carcinoma cells. At a 1% salt concentration, the growth inhibitory rate of potassium bamboo salt was 54%, higher than that of 1 time baked bamboo salt (36%). However, purified salt and solar salt showed relatively lower inhibitory effects of 19% and 23%, respectively. To determine the inhibitory mechanisms of potassium bamboo salt, the expression levels of Bax and Bcl-2 genes in HCT-116 cells were determined by RT-PCR. Potassium bamboo salt significantly increased Bax and decreased Bcl-2 expression levels unlike bamboo salt, purified salt, and solar salt (p<0.05). Therefore, addition of potassium to salt decreased co-mutagenicity and increased in vitro antioxidative and anticancer effects.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.1
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• pp.1-10
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• 1996

뇌졸중이라고 진단된 입원 환자 26명을 대상으로 3일동안 섭취한 식이와 24시간 뇨와 혈액을 수집하고 혈압을 측정하여 나트륨, 칼륨, 캄슘, 마그네슘의섭취 수준에 다른 뇨중 배설량과 혈중 수준을 관찰하고 이들과 혈압과의 관계를 알아봄으로써 뇌졸중 환자를 포함한 고혈압 관리의 치료식이를 제공하는데 기초자료로 사용하고자 실시간 연구결과를 요약하면 다음과 같다. 1. 대상자들의 평균 연령은 남녀 각각 52.6세, 58.5세였으며 평균 BMU는 남녀 각각 21.6, 22.4였다. 입원 당시 평균 혈압은 남녀 각각 147.3/90.9mmHg, 162.7/102.0mmHg였고, 실험 종료일의 평균 혈압은 남자의 경운 124.6/80.8mmHg 였고 여자 대상자는 137.7/91.3mmHg 였다. 2. 1일 평균 나트륨, 칼륨, 칼슘, 마그네슘의 섭취 향은 96.7$\pm$30.7mEq,64.8$\pm$19.0mEq, 431.3$\pm$227.1mg, 333.9$\pm$145.9mg이었다. 3. 1일 평균 뇨중 나트륨, 칼륨, 칼슘, 마그네슘의 배설량은 76.7$\pm$28.2mEq, 33.9$\pm$16.6mEq, 65.6$\pm$34.0mg, 96.5$\pm$58.0mg이었다. 4. 평균 혈청내 나트륨, 칼륨, 칼슘, 마그네슘의 함량은 137.8$\pm$4.3mEq/l, 3.7$\pm$0.5mEq/l, 7.6$\pm$0.8mg/dl, 2.2$\pm$0.2mg/dl로써 칼슘 농도가 정상수준에 비해 비교적 낮은 것으로 나타났다. 5. 혈압과 무기질과의 관계에서 수축시 혈압의 증가시 뇨중 칼륨 배설이 증가함으로써 수축기 혈압과 뇨중 칼륨 배설량 사이에 유의적인 부의 상관관계가 나타났다. (p<0.05). 이상과 같은 입원중인 뇌졸중 환자의 뇨중 나트륨과 칼륨의 배설률 및 혈청과 뇨중 칼슘 배설수준이 정상인 보다 낮은 수준이었으며, 칼륨은 뇌졸중 환자의 혈압관리에 효과적이 무기질로 작용할 가능성이 보여지므로 고혈압관리를 위한 식사 처방시 이들 무기질에 대한 고려가 있어야 할 것으로 사료된다.

• Journal of the Korean Chemical Society
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• v.17 no.5
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• pp.378-384
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• 1973

To investigate the mechanism of the reaction of electrolytic oxidation of iodide to iodate ions, polarization curves are determined in various kinds of solution using electrodeposited lead peroxide and platinum anodes. It was observed from the polarization curves that the limiting current is exists at concentration 1.5 M of potassium iodide, and these limiting current disappeared as potassium hydroxide was added up to concentration of 0.1 M. while in case of platinum anode, limiting current did not appear in dilute potassium iodide solution. These results are owing to the chemical reaction, $PbO_2+2I^{-}+2H^+{\to}PbO+I_2+H_{2}O$ ocurring at the surface of lead peroxide anode. Also, we studied to obtain the optimum conditions of electrolytic preparation of iodate from iodide solution using a cell without the diaphragm. The results are that; (a) addition of potassium dichromate at the anti-reducing agent is proper in concentration of 0.1 g/l, (b) electrolytic temperature is not so much effective in raising the current efficiency, (c) current efficiency is increased with current density, and (d) electrolysis is the most effective in weak alkaline solutions.

• Resources Recycling
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• v.25 no.3
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• pp.43-48
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• 2016

Cement manufacturing plant uses various kinds of industrial/municipal waste. The waste contains considerable amount of potassium, chlorine and small amount of heavy metal. Many researches were performed to fabricate valuable resources from the waste. In this study, various methods, which dissolves and crystallizes potassium/chlorine to extract potassium chloride, were experimented. Especially amount of water, slurry temperature, and stirring time were controlled. Then kind of heavy metal and content of potassium chloride were analyzed. The yield of potassium chloride increased, as the amount of water for slurry increased but it increased slightly, when the water content was over 200%. The yield tended to increase, when the temperature of slurry was over a certain point. The yield did not increase in case of over 10 minutes stirring time. The kind and content of heavy metal in potassium chloride were various according to stirring time. The main heavy metals were Pb, Cu, and $Cr^{6+}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1303-1317
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• 2013

The purpose of this study was to determine the sodium (Na) and potassium (K) content of school meals served in elementary and junior high school in Korea. In this study, 872 kinds of school meal dishes were collected from twelve elementary and twelve junior high schools located in four different cities in Korea (Daegu, Masan, Gwangju, and Jeju). The dishes were classified into three main categories; staple dish, subsidiary dish, and dessert. Each main category was further sub-classified into 4 kinds of staple dishes, 15 kinds of subsidiary dishes, and 5 kinds of dessert dishes. The Na and K content of dishes were then analyzed by atomic absorption spectroscopy. The Na content of individual dishes showed considerable differences, ranging from 9 to 2,717 mg/100 g. Among the staple dishes, cooked rice contained relatively less Na, but other staple dishes such as a la carte, noodle, and rice-gruel contained considerably high amounts of Na. Regarding the subsidiary dishes, the Na content of salad was low, but those of Jangachi, stir-fried dishes, and kimchi were considerably high. Among the dessert dishes, beverages, fruit, and milk/dairy products contained relatively low amount of Na, while rice cakes and baked goods, and snacks contained noticeably high amounts of Na. Unlike the Na content, the K content between the dishes did not show much variability. Cooked rice and rice cakes contained relatively low amounts of K, similar to other dishes, and ranged from 104 to 220 mg/100 g. The Na/K ratio was especially high in rice cakes and Jangachi, while of the ratio in beverages, milk/dairy products, salad, and fruit were pretty low. The total content of Na and K and the Na/K ratio of elementary school meals were 974 mg, 378 mg and 2.7, respectively, and those in junior high school meals was 1,466 mg, 528 mg and 3.0. The results show that most school meals provide a significant amount of Na but significantly small amounts of K, as suggested by the Dietary Reference Intakes for Koreans.

• Childhood Kidney Diseases
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• v.11 no.1
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• pp.9-15
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• 2007

Purpose : Edema is one of the cardinal features of nephrotic syndrome. Although the pathogenesis of edema is not entirely understood, it is caused by hypovolemia or hypervolemia by different mechanisms. Accordingly it is important to evaluate the volume status of patients in order to treat the edema, but it is difficult to evaluate the patient's volume status only by clinical parameters. The quotient of urine sodium and potassium excretion $U_K/(U_{Na}+U_K)$ is introduced as a more useful way to evaluate volume status. In this study we will propose the usefulness of $U_K/(U_{Na}+U_K)$ in evaluating the volume status of children with nephrotic syndrome. Methods : Primary nephrotic syndrome patients at Yeungnam University Hospital since January 1995 to June 2005, were included in the study. We analyzed clinical parameters such as tachycardia, cardiomegaly, pleural effusion, blood chemistry and urinalysis prospectively. We defined hypovolemia when $U_K/(U_{Na}+U_K)$ exceeded 60%. Intravenous albumin and diuretics were administered to hypovolemic edematous patients. On the other hand, hypervolemic edematous patients were treated only with diuretics. Results : There were 50 cases of primary nephrotic syndrome patients(hypervolemia: 29 vs hypovolemia: 21). There were no significant differences in clinical symptoms and laboratory findings except for FeNa While $F_eNa$ and $U_K/(U_{Na}+U_K)$ had a significant negative correlation, BUN and $U_K/(U_{Na}+U_K)$ had a significant positive correlation. Urine output after edema treatment was effective and there were no treatment-related side effects in both groups. Conclusion : FeNa, BUN and $U_K/(U_{Na}+U_K)$ are a useful parameters for evaluating volume status of edematous nephrotic syndrome patients. We could suggest a therapeutic option for using albumin and/or diuretics according to volemic status by means of measured $U_K/(U_{Na}+UK)$.