• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.944-950
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• 1999

Hexavalent chromium (CrVI) was fed to one day old chicks of Gallus domesticus in the form of different concentrations (250 and 500 mg/kg feed) of potassium dichromate mixed with the feed, ad libitum, for 32 weeks. After 20 weeks of feeding, the total body weight was higher in the low dose (260 mg/kg (feed) group and lower in the high dose (500 mg/kg feed) group, as compared with the control chicks. After 32 weeks of feeding, however, the total body weight was significantly decreased in both the treated groups. Egg laying was enhanced. Fertility remained unaffected, whereas hatchability was considerably decreased after CrVI-treatment. The egg shell thickness increased significantly (13%). Cr was deposited in a dose dependent manner in the liver and lungs. Some structural derangements in liver were also noted in treated chicks. The results of this study i.e., rapid ageing, excessive Cr deposition, decreased hatchability and hepatotoxicity indicate toxic effects of CrVI.

• Journal of the Korean Society of Costume
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• v.27
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• pp.121-132
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• 1996

This study showed the proper pigment extract in the Phe. Dyeing which is the basic dye of the natural plants dyeing,. Also it compared and examined the K/S the promotion of the color fastness and the effect of color difference change were attended by mordants and method of mordanting. 1. The most absorbance of Phellodendron. sol-ution is 330nm berberine is 430nm. 2. The best and proper temperature to extrat Phe,. was 80 and dyeing solution for 24 hours. 3. The pH effect was stable in the absorbances and color differences change. 4. Mordanted group increased the absorbances compared to non-mordanted sample. In case depth the most absorbance of Al. Sn. K. Cu and C. A solution were in 3% Fe and Cr were in 5%. In the color difference change they became dark reduced greenish and increased yellowish when their absorbances were in 3% 5. K./S was recoginzed by tainnin and fe, K/S was more increased pre-mordants than post-mordants. 6. Fe is the unchangable mordant in the color difference change and pre-mordants is more stable than post-mordants in the difference color. 7. Generally light C. F indicated more than grade 2 and light C. F, was much improved in post-mordanted by alumium potassium potass-ium dichromate. Washing C.F was improved in mordanted by tainnin and ferrous suulfate mordanted group was better than non-mordanted sample. Perspir-ation C,F was more stable in acid than alkali. Dry cleaning C.F indicated more than grade. 4.

• Journal of Environmental Science International
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• v.23 no.2
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• pp.181-192
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• 2014

In Korea, the chemical oxygen demand($COD_{sed}$) in freshwater sediments has been measured by the potassium permanganate method used for marine sediment because of the absence of authorized analytical method. However, this method has not been fully verified for the freshwater sediment. Therefore, the use or modification of the potassium permanganate method or the development of the new $COD_{sed}$ analytical method may be necessary. In this study, two modified $COD_{sed}$ analytical methods such as the modified potassium permanganate method for $COD_{Mn}$ and the modified closed reflux method using potassium dichromate for $COD_{Cr}$ were compared. In the preliminary experiment to estimate the capability of the two oxidants for glucose oxidation, $COD_{Mn}$ and $COD_{Cr}$ were about 70% and 100% of theoretical oxygen demand(ThOD), respectively, indicating that $COD_{Cr}$ was very close to the ThOD. The effective titration ranges in $COD_{Mn}$ and $COD_{Cr}$ were 3.2 to 7.5 mL and 1.0 to 5.0 mL for glucose, 4.3 to 7.5 mL and 1.4 to 4.3 mL for lake sediment, and 2.5 to 5.8 mL and 3.6 to 4.5 mL for river sediment, respectively, within 10% errors. For estimating $COD_{sed}$ recovery(%) in glucose-spiked sediment after aging for 1 day, the mass balances of the $COD_{Mn}$ and $COD_{Cr}$ among glucose, sediments and glucose-spiked sediments were compared. The recoveries of $COD_{Mn}$ and $COD_{Cr}$ were 78% and 78% in glucose-spiked river sediments, 91% and 86% in glucose-spiked lake sediments, 97% and 104% in glucose-spiked sand, and 134% and 107% in glucose-spiked clay, respectively. In conclusion, both methods have high confidence levels in terms of analytical methodology but show significant different $COD_{sed}$ concentrations due to difference in the oxidation powers of the oxidants.

• Journal of Oral Medicine and Pain
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• v.25 no.4
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• pp.355-364
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• 2000

This study was to find dental materials causing hypersensitivity reactions by carrying out patch tests in the patients with oral mucosal lesions to investigate the possibility of hypersensitivity reactions in etiology of oral mucosal lesions. 31 patients (female 26, male 5, age range 24-72 years) with oral mucosal lesions were classified as patient group, and 41 volunteers (female 24, male 17, age range 23-40 years) without oral mucosal lesion, systemic disease and history of allergy as control group. The obtained results were as follows: 1. There were various dental restorations in most of patient group and control group, 29(94%) in 31 patient group, 35(85%) in 41 control group. 2. Among sites of oral mucosal lesions, buccal mucosa was the most common site with 60%, followed by gingiva with 24%, tongue with 16%. Lesions in contact with restorations were highly 90% in tongue and 89% in buccal mucosa, but comparatively lower 53% in gingiva. 3. The ratio of positive reactions to the patch test in patient group was significantly higher than the control group (p<0.05). 4. Dental materials causing positive reactions to the patch test were mainly mercury(19%), potassium dichromate(16%), cobalt chloride(16%) in patient group, cobalt chloride(17%) in control group. 5. In 20 patients with lichen planus, 8 patients(40%) showed positive reactions to the patch test.

• The Journal of the Korean dental association
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• v.52 no.2
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• pp.96-104
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• 2014

The aim of this study was to investigate the frequency of positive patch test reaction to dental materials in patients with oral mucosal diseases. Epicutaneous patch test was performed in 110 patients with oral mucosal diseases; 41 patients with oral lichen planus(OLP), 44 patients with burning mouth syndrome(BMS), 25 patients with other oral mucosal diseases including recurrent aphthous ulcer and mucous membrane pemphigoid. The obtained results were as follows: Oral gold restorations were most common in patents with oral mucosal diseases and porcelain fused metal crown, implant appeared in the order. 33 of 110 patients did not appear skin reactions (negative, 30%) and 77 patients (positive, 70%) had skin reactions including redness, rash, blisters. Dental materials causing positive reaction to patch test were mainly as gold-sodium-thiosulfate (26.7%), nickel sulfate(Ni) (22.7%), cobalt chloride(Co) (14.7%), palladium chloride(Pd) (11.9%), potassium dichromate (10.7%) in order, respectively. In conclusion, old metal restorations could be the cause of oral mucosal diseases and epicutaneous patch test could be used as a tool to improve the oral conditions.

• Safety and Health at Work
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• v.11 no.4
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• pp.500-508
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• 2020

Background: Research on the status of many chemicals used in the semiconductor industry is needed. The purpose of this study was to describe the overall status of chemical use in the semiconductor industry in Korea and to examine it from a health perspective. Methods: Data on the status of chemical use and safety data sheets at 11 of 12 major semiconductor workplaces in Korea were collected. The number of chemical products and chemical constituents, quantities of chemicals, and trade secret ingredients used, as well as the health hazards were examined. Results: On average, 210 chemical products and 135 chemical constituents were used at the surveyed workplaces. Among all chemical products, 33% (range: 16-56%) contained at least one trade secret ingredient. Most of the trade secret ingredients were used in the photolithography process. Several carcinogens, including sulfuric acid, chromic acid, ethylene oxide, crystalline silica, potassium dichromate, and formaldehyde were also used. Only 29% (39 of 135) of the chemical constituents had occupational exposure limits, and more than 60% had no National Fire Protection Association health, safety, and reactivity ratings. Based on the aforementioned results, this study revealed the following. First, many chemical products and constituents are being used in the semiconductor industry and many products contained trade secret ingredients. Second, many products contained significant amounts of carcinogenic, mutagenic, and reproductive toxicant materials. Conclusion: We conclude that protecting workers in the semiconductor industry against harm from chemical substances will be difficult, due to widespread use of trade secret ingredients and a lack of hazard information. The findings of the status of chemical use and the health and safety risks in semiconductor industry will contribute to epidemiological studies, safe workplace, and worker health protection.

• Parasites, Hosts and Diseases
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• v.32 no.1
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• pp.7-12
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• 1994

A calf and 50 mice were infected with Cryptosporidium parvum and their fecal materials were collected and treated 10 ether extraction (EE), followed by discontinuous sucrose gradients (DSG) method. EE method was to remove some of fat or lipid from feces. Sediments were washed by centrifugation ($1,500{\;}{\times}{\;}g$ for 10 min., 3 times) In phosphate-buffered saline and then these washed sediments were sleeved sequentially through stainless steel screens with a final mesh of 250 ($61{\;}{\mu\textrm{m}}$ porosity) to remove other debris. After sieving, the materials were suspended in 2.5% potassium dlchromate solution. Oocysts were counted by using a hemocytometer and the recovery rate of pure oocysts was calculated on the basis of the count. Following centrifugation ($1,500{\;}{\times}{\;}g$ for 30 min.) by DSG method, most oocysts were recovered at the interface between a gravity of 1.103 and 1.064. The recovery rates of pure oocysts from the fecal suspension of the calf ($3.8{\;}{\times}{\;}10^7/ml$) and the mouse ($3.2{\;}{\times}{\;}10^6/ml$) treated with EE method were 81.6% and 51.6%, respectively. It is suggested that the recovery rate was dependent on the number of oocysts In each suspension treated with EE method. To get the 50% recovery rate, there must be more than $2{\;}{\times}{\;}10^6$ oocysts per ml of the fecal suspension treated with EE method. By the combination of the two methods it was possible to isolate C. parvum oocysts from normal feces of the calf and mouse as well as from dlarrhelc feces.

• Journal of Internet of Things and Convergence
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• v.6 no.4
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• pp.33-38
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• 2020

It was reported that a mobile application was designed to easily provide natural dyeing information such as natural dye related resources, colors and dyed fabrics in 2007. Since studies on the linkage, application, etc. between natural dye dyeing and IoT are still lacking, diversity of information on the change of dyeing pattern by natural dye dyeing is required. In this study, it was to construct dyeing information by natural dyes, e.g., Lithospermum erythrorhizon, on silk, which has been traditionally used as many fibers in Korea. The extraction of the dye from L. erythrorhizon was carried out under pH4. The dried root of L. erythrorhizon showed dark brownish purple. Silk fabric by a without a mordant typically showed a purple dyed pattern. In the staining by sodium tartrate plus citric acid, silk fabric was stained clear brown. Interestingly, the mordant of iron (II) sulfate, the silk fabric was dyed in a light gray color rather than black. When the mordant of aluminum potassium sulfate was treated with L. erythrorhizon-extracted dye, the results were almost the same as when the mordant was not treated. When the degree of dyeing was evaluated numerically, the treatment of the mordant of potassium dichromate was about 50% darker, and the dyeing by iron (II) sulfate was about 75% darker. These results will be helpful in the study of applying various dye colors using L. erythrorhizon, and it will provide information on dyeing controller and database system construction by dyeing parameters such as dyeing degree, pH concentration, and chromaticity change.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.4
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• pp.370-376
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• 1997

Experiments were conducted to investigate the effects of chromium application level, soil pH change, soil topping, application of some metals and application of organic matter on the absorption of chromium by radish and its growth. The results of experiments are summarized as following. Application of chromium as potassium dichromate up to 50 mg/kg did not affect the germination of radish seed. Application of chromium above this level affected the germination abversely. The dry matter yield of and absorption of chromium by radish was not affected by the application of chromium up to 100 mg/kg. Increased in soil pH decreased the uptake of chromium by radish under all range of chromium application rates. Under acidic condition (pH 5-6), the increase in the application of chromium resulted in the increase in the uptake of chromium by radish and lowering of dry matter production of radish. However, under alkaline condition (pH 7-8), increased application of chromium did not affect the uptake of chromium and the dry matter yield of radish. The application of Zn, Fe and Cu, up to 100 mg/kg did not affect not affect the uptake of chromium and dry matter yield of radish. The topping of soil with untreated soil after application of chromium up to five cm, did not affect the chromium uptake of radish, the same treatments tended to increase the dry matter yield of radish. The application of organic fertilizer(obtained from local market) up to the amount equivalent to 3000 kg/ha, although increased the dry matter yield of radish, did not affect the uptake of chromium by radish significantly. All the treatments tested in this study did not affect the translocation of chromium between root and shoot of radish.

• Journal of Preventive Medicine and Public Health
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• v.37 no.2
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• pp.157-165
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• 2004

Objectives : This study aimed to investigate the toxic effects of chromium (VI) on the placental function and reproduction in rats. For the study, the placental prolactin-growth hormone (PRL-GH) gene expression, placental trophoblast cell differentiation and reproductive data were analyzed. Methods : The pregnancies of F344 Fisher rats were checked by the presence of a copulatory plug or sperm in the vaginal smear, which was defined as day 0 of the pregnancy. Pregnant rats were divided into the three groups. The control group was given tap water (chromium level < 0.001 ppm) and the remaining groups were given 250 or 750 ppm of chromium (VI) [as potassium dichromate], from day 7 to 19 of the pregnancy. Rats were sacrificed at days 11 and 20 of pregnancy. The mRNA levels of PRL-GH and Pit-1a and b isotype genes were analyzed by Northern blot hybridization and reverse transcription-polymerase chain reaction (RT-PCR). The hormonal concentration was analyzed by radioimmunoassay, and the differentiation of placental trophoblast cells were observed by histochemical studies. Reproductive data, such as placental and fetal weights, pregnancy period, and litter size, were surveyed at day 20 of pregnancy and after birth. A statistical analysis was carried out using the SAS program (version 8.1). Results : The mRNA levels of the prolactin-growth hormone (PRL-GH) family of genes were dose dependently reduced by chromium exposure. The mRNA levels of Pit-1a and b isotype genes that induce the expression of the PRL-GH family of genes were also reduced by chromium exposure. The PRL-GH hormonal concentration in the rat placenta, fetus and maternal blood were decreased by chromium exposure. In the middle stage of pregnancy (day 11), a high dose of chromium suppressed the differentiation of spongiotrophoblast cells that secret the PRLGH hormones. In the last stage of pregnancy (day 20), a high dose of chromium induced apoptosis of placental cells. Reproductive data, such as placental and fetal weights, litter size, were reduced, but the pregnancy period was extended in the group exposed to chromium compared with the controls. Conclusion : Chromium (VI) disrupts the ordered functions of the placenta, which leads to reproductive disorders in rats.