• Title, Summary, Keyword: Copper

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Oxidative Modification of Neurofilament-L by Copper-catalyzed Reaction

  • Kim, Nam-Hoon;Kang, Jung-Hoon
    • BMB Reports
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    • v.36 no.5
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    • pp.488-492
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    • 2003
  • Neurofilament-L (NF-L) is a major element of neuronal cytoskeletons and known to be important for neuronal survival in vivo. Since oxidative stress might play a critical role in the pathogenesis of neurodegenerative diseases, we investigated the role of copper and peroxide in the modification of NF-L. When disassembled NF-L was incubated with copper ion and hydrogen peroxide, then the aggregation of protein was proportional to copper and hydrogen peroxide concentrations. Dityrosine crosslink formation was obtained in copper-mediated NF-L aggregates. The copper-mediated modification of NF-L was significantly inhibited by thiol antioxidants, N-acetylcysteine, glutathione, and thiourea. A thioflavin-T binding assay was performed to determine whether the copper/$H_2O_2$ system-induced in vitro aggregation of NF-L displays amyloid-like characteristics. The aggregate of NF-L displayed thioflavin T reactivity, which was reminiscent of amyloid. This study suggests that copper-mediated NF-L modification might be closely related to oxidative reactions which may play a critical role in neurodegenerative diseases.

Copper Electrode Material using Copper Formate-Bicarbonate Complex for Printed Electronics

  • Hwang, Jaeeun;Kim, Sinhee;Ayag, Kevin Ray;Kim, Hongdoo
    • Bulletin of the Korean Chemical Society
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    • v.35 no.1
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    • pp.147-150
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    • 2014
  • Copper ink has been prepared by mixing copper(II) formate and 2-ethyl-1-hexylammonium bicarbonate (EHABC) to overcome some weak points such as aggregation and degradation of copper nano-type ink. Ink was coated on glass substrate and calcined at $110^{\circ}C$ to $150^{\circ}C$ to generate electrically conductive copper film under two different atmospheres such as nitrogen gas and gaseous mixture of formic acid and methanol. The lowest resistivity of $1.88{\mu}{\Omega}{\cdot}cm$ of copper film was obtained at $150^{\circ}C$ in gaseous formic acid condition. The long-term resistivity shows to increase from $1.88{\mu}{\Omega}{\cdot}cm$ to $2.61{\mu}{\Omega}{\cdot}cm$ after one month.

Review of Copper Trihydroxychloride, a Green Pigment Composed of Copper and Chlorine (구리와 염소 주성분 녹색 안료 코퍼 트리하이드록시클로라이드(Copper Trihydroxychloride)에 대한 고찰)

  • Oh, Joonsuk;Lee, Saerom;Hwang, Minyoung
    • MUNHWAJAE Korean Journal of Cultural Heritage Studies
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    • v.53 no.2
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    • pp.64-87
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    • 2020
  • Copper trihydroxychloride (atacamite, botallackite, paratacamite, etc.), the first green pigment used in Mogao Grotto's mural paintings of China, has been known as "copper green", "green salt", and "salt green", etc. and has been used as an important green pigment with malachite. At first, the natural mineral atacamite was employed, but after the Five Dynasties (907~960 CE), synthetic copper trihydroxychloride was primarily used. In Chinese literature, copper green, green salt, and salt green are recorded as being made via reaction with copper powder, Gwangmyeongyeom (natural sodium chloride), and Yosa (natural ammonium chloride), and the prepared material was analyzed to be copper trihydroxychloride. Copper trihydroxychloride pigment was not found in paintings prior to the Joseon Dynasty (1392~1910 CE) in Korea. In analysis of the green pigments used in paintings and the architectural paintworks in the Joseon Dynasty, copper trihydroxychloride was also shown to have been used as an important green pigment with malachite (Seokrok). In particular, the proportion of copper trihydroxychloride use was high in Buddhist paintings, shamanic paintings, and dancheongs (decorative coloring on wooden buildings). Some of these turned out to be synthetic copper trihydroxychloride, but it is unclear whether the rest of them are synthetic or natural pigments due to a lack of analyzed data. From literature and painting analyses, the pigment name of copper trihydroxychloride in the Joseon Dynasty turns out to be Hayeob, a dark green pigment. It is believed to have first been prepared by learning from China in the early Joseon period (early 15th century) and its use continued until the late 19th century with imported Chinese pigment. Round or oval particles with a dark core of copper trihydroxychloride which were used in Chinese literature were similar to the synthetic copper trihydroxychloride pigments used in the Joseon Dynasty and Chinese paintings. Therefore, the synthetic copper trihydroxychloride pigments of Korea and China are believed to have been prepared in a similar way.

Aggregation of Thin Copper Wire by Ball Milling Treatment (볼밀처리에 의한 구리세선의 응집)

  • Hwang, Jisu;Cho, Seong Su;Seong, Chang Jun;Yoo, Kyoungkeun
    • Resources Recycling
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    • v.29 no.4
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    • pp.67-72
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    • 2020
  • Recycling processes of spent copper wires cosisnt of several steps of cutting and chopping processes for peeling covering materials followed by gravity separation processes, where copper is recovered. Because copper thin wires could be lost during further recycling processes, the wire may need to be further treated. In the present study, the copper thin wire was treated with ball milling to prevent the loss. Since the aggregation of the copper wire could be formed by bending and entangling the copper wire each other, the degree of flexion of the copper wire was measured after ball milling. When the 0.5 cm and 3 cm copper wires were used, the 0.5 cm copper wire was not bent and the 3 cm copper wires were aggregated regardless of the ball addition. When the 1 cm and 2 cm copper wires were used, the degree of flexion was remarkable when the balls were added. In the tests using 2 cm copper wires, the aggregation ratio of the copper wire gradually increased with the amount of the 20 mm alumina ball, and when 200 ml of 30 mm alumina ball was used, the aggregation ratio increased to 89.29 %, but after increasing the ball amount further, the aggregation ratio decreased. Thus, it is expected that the loss of the copper wire could be reducedif when the copper thin wire is treated with ball milling by the aggregation of copper thin wires.

A Regional Study for Developments of Kyeongnam Copper Metallogenic Province (경남지구(慶南地區) 동광상(銅鑛床)의 종합개발(綜合開發)에 관(關)한 조사연구(調査硏究))

  • Kim, Sun Uk
    • Economic and Environmental Geology
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    • v.6 no.3
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    • pp.133-170
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    • 1973
  • The metamorphosed belt on cherty and andesitic rocks of the Gyeongnam province area has been well known as the most important copper matallogenetic province in Korea and locally has been investigated by several geologists. This report is summarized about geology, occurrence of ore deposits, the study of the present status of mine developments and exploitations and the suggestions of future proposed of copper mine developments and harmoniously and reseonably planning of demands and supply of copper ore. For convenience of study the writer divided the survey region as 4 areas, according to the conditions of mine location. They are (1) Goseong copper area (2) Gunbuk-Haman copper area (3) Masan-Changwon copper area (4) Tongrae-Ilgwang copper area. The geology of the above 4 areas consits of Cretaceous Gyongsang System, which is divided into Silla series, Nakdong Series and Bulguksa Series. The former has intrusive and extrusive andesite and sedimentary formation, and the latter has dioritic and hornblende granite. Ore deposits which is mostly vein types are confined mostly in the andesite and cherty rocks of Silla and Nakdong Series. It is observed slight hydrothermal alteration, i. e. propylitization, chloritization, saussuritization and silicification. It seems that the ore was formed by hydrothermal solution and secondary enrichement. The ore minerals are mainly chalcopyrite and pyrite, with small amounts of malachite, azurite, chalcocite, cuprite, galena, and sphalerite, magnetite, tetrahedrite and etc.. The efficient plan of copper mine developments in surveyed region are as following; (a) Gyeongnam Copper districts are divided in 4 area as mentioned above. (b) Each area would be likely developed as group-working as one unit. For the sufficiently supplying a demand of electric copper, the importations of high grade copper ore in foreign country are invitable at present status of copper mine developments and exploitations.

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Effect of Copper on the Growth and Methanol Dehydrogenase Activity of Methylobacillus sp. Strain SK1 DSM 8269

  • Kim, Si W.;Kim, Young M.
    • Journal of Microbiology
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    • v.34 no.2
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    • pp.172-178
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    • 1996
  • Methylobacillus sp. strain SK1, which grows only on methanol, was found to grow in the absence of added copper. The doubling time (t$_{d}$ = 1.3 h) of the bacterium growing at the exponential growth phase at 30.deg.C in the absence of copper was the same as that of the cell growing in the presence of copper. The bacterium growing after the exponential phase in the absence of copper, however, grew faster than the cell growing in the presence of copper. Cells harvested after thee arly stationary phase in the presence of copper were found to exhibit no methanol dehydrogenase (MDH) activity, but the amount and subunit structure of the enzyme in the cells were almost the same as that in cells harboring active MDH. Pellets of the cells harvested after the early stationary phase in the presence of copper were pale green. Cell-free extracts prepared from cells harvested at the early stationary phase in the presence of copper were pink and exhibited MDH activity, but it turned dark-green rapidly from the surface under air. The green-colored portions of the extracts showed no MDH activity and contained c-type cytochromes that were oxidized completely. The inactive MDH activity and contained c-type cytochromes that were oxidized completely. The inactive MDH proteins in the green portions were found to have antigenic sites identical to those of the active one as the inactive MDHs in cells grown in the presence of copper. The bacterium was found to accumulate copper actively during the exponential growth phase. MDH prepared from cells grown in the presence or absence of copper was found to be more stable under nitrogen gas than under air. Methanol at 10 mM was found to enhance the stability of the MDH under air.r.

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Hematological and serum biochemical studies in fresh water fish exposed to acute and chronic copper and mercury toxicity

  • H.A., Sawsan;H.M., Amira;M.B., Mostafa;AM.M., Nashaat
    • Journal of fish pathology
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    • v.30 no.1
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    • pp.25-39
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    • 2017
  • A total number of 668 apparently healthy fish were obtained from farm to study the effect of two heavy metals in a form of (Copper sulfate and Mercuric chloride) on some hematological and biochemical parameters of blood. The $LC_{50}$ /96 hr. of Cu and Hg were estimated and fish exposed to $\text\tiny{^1/_2}$ $LC_{50}$ for 7 days and for $1/_{10}$ $LC_{50}$ for 8 weeks from each product separately. Results showed decrease in RBCs count, PCV% and Hb in acute and chronic mercury while a significant increase was shown in acute and chronic copper toxicity, total leucocytic count showed decrease in acute mercury toxicity and increase in the chronic case, while in copper toxicity non-significant decrease in acute and significant decrease in chronic toxicity was noticed. Elevated serum urea and creatinine in both acute and chronic mercury and copper toxicity was detected. No changes in total bilirubin in the acute mercury and chronic copper toxicity while significant increase in chronic mercury and acute copper. Elevation of serum AST and ALT in some days of acute toxicity of mercury and copper while in chronic mercury toxicity a significant elevation of both serums AST and ALT were detected .while in chronic copper toxicity serum AST was fluctuated and ALT showed no significant changes. CK study revealed significant decrease in acute mercury with fluctuation in the chronic toxicity while in copper toxicity it showed fluctuation in acute and significant decrease in chronic toxicity. Glucose value decreased in acute and chronic mercury toxicity while in copper toxicity it showed significant increase in the acute and increase followed by significant decrease in the chronic copper toxicity.

Biocides Effect on the Microbiologically Influenced Corrosion of Pure Copper by Desulfovibrio sp.

  • Onan, Mert;Ilhan-Sungur, Esra;Gungor, Nihal Dogruoz;Cansever, Nurhan
    • Journal of Electrochemical Science and Technology
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    • v.9 no.1
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    • pp.44-50
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    • 2018
  • The aims of this study were to determine the corrosion behavior of pure copper in the presence of Desulfovibrio sp. and also to investigate the effects of glutaraldehyde (GD) and isothiazolinone (ISO) on the corrosion behavior of pure copper in the presence of this sulfate-reducing bacteria (SRB) strain by using electrochemical techniques. Electrochemical measurements of pure copper were carried out at specified time intervals (0, 8, 24, 48, and 96 hr) over a period of exposure. Corrosion rates of pure copper from anodic and cathodic Tafel slopes and corrosion potential ($E_{corr}$) were determined. Biofilm and corrosion products on the copper surfaces were observed by Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-Ray Spectrometry (EDS) analyses. The effects of solution types (PC (Postgate's C medium) and SRB (Desulfovibrio sp.)) and exposure times of copper and biocides (ISO or GD) on the corrosion rates of pure copper were evaluated by statistical analyses. As a result of the FESEM analysis, biofilm formation was observed on the surfaces of pure copper exposed to the Desulfovibrio sp. cultures both with and without the biocides. The results show that the pure copper was corroded by Desulfovibrio sp. However, the addition of GD or ISO to the Desulfovibrio sp. culture resulted in a decrease in the corrosion rate of the pure copper. It was also observed that both of the biocides showed a similar effect on pure copper's corrosion rate caused by Desulfovibrio sp.

Application of Copper Slag as Sand Substitute in SCP Pilot tests (SCP 현장시험시공을 통한 동슬래그의 모래대체재로서의 적용성 연구)

  • 천병식;정헌철;김경민
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.613-620
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    • 2002
  • Sand Compaction Pile(SCP) is a soil improvement method that a sand charge is introduced into the pipe, and the pipe is withdrawn part away while the sand pile is compacted and its diameter is enlarged. The sand used in this method should be of good quality. In Korea, crushed stone and washed sea sand are used frequently in SCP. However, use of these materials is restricted because of environmental problem and deficiency of supply. In the copper smelting process, about 0.7 million tons of copper slag are produced in Korea. The range of particle size distribution of copper slag is from 0.15mm to 5mm, so it can be a substitute for sand, and the relatively high specific gravity compared with the sand, is its characteristic. Copper slag is hyaline and so stable environmentally that in foreign country, such as Japan, Germany etc., it is widely used in harbor, revetment and offshore structure construction works. Therefore, in this study, the several laboratory tests were peformed to evaluate the applicability of copper slag as a substitute for sand of SCP. From the mechanical property test, the characteristics of sand and copper slag were compared and analyzed, and from laboratory model test, the strength of composite ground was compared and analyzed by monitoring the stress and ground settlement of clay, SCP and copper slag compaction pile. Specially, this study focused on the application of copper slag as sand substitute in SCP pilot tests based on laboratory tests results.

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A comparative study of the quantitative assessment on the panoramic and intraoral radiographs (파노라마 방사선사진과 구내 방사선사진에서 골조직 정량평가의 비교연구)

  • Kim Jae-Duk
    • Imaging Science in Dentistry
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    • v.31 no.3
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    • pp.129-133
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    • 2001
  • Purpose: To compare the copper equivalent values measured at premolar and molar areas in the copper equivalent images of panoramic and intraoral radiographs and to evaluate the possibility of the copper equivalent images of panorama for the assessment the bone density. Materials and Methods : Intraoral radiograms at mandibular premolar and molar area and panoramas of 6 human dry skulls were taken with copper-step wedge by Heliodent MD (Siemens Co., Germany) and by Planmeca (PM 2002 CC, Planmeca, Helsinki, Finland) were used for experiment. The copper equivalent values measured at premolar and molar areas in the copper equivalent im ages of panorama and intraoral film were compared. Results: The copper equivalent values were ranged 0.20 mmCu-0.44 mmCu at the molar areas, 0.05 mmCu-0.31 mmCu at the premolar areas on panoramic images. There were no significant differences (p>0.5) between the copper equivalent values on intraoral images and those on panoramic images measured at premolar areas and molar areas respectively. The correlation coefficient between the copper equivalent values on intraoral images and those on panoramic images was respectively 0.8495 at molar areas and 0.6184 at premolar areas. Conclusions : The copper equivalent images of panorama for the assessment the bone density appeared to be significant at molar area compared with the one of intraoral radiograph.

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