Articles de revues : « Copper exclusion »

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Xie, Xiao Yan, Li Li Xu et Dong Mei Gao. « Effect of CuO Nanoparticles on the Cell Membrane Permeability of A549 and its Exclusion ». Advanced Materials Research 343-344 (septembre 2011) : 77–80. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.77.

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This study was conducted to explore the effect of CuO nanoparticles (NPs) on the cell membrane permeability and its exclusion from cells. Human A549 lung cells were exposed to 5mg/L and 15mg/L CuO NPs. Cell membrane permeability was evaluated in 2h and 4h. After 4 hours exposure, the membrane was damaged. Exclusion of copper from cells after 24h exposure with 5mg/L and 15 mg/L CuO NPs are time and dose dependent. And the cell viability was resumed gradually. It is concluded that CuO NPs could induce cytotoxicity, and destroy the membrane integrity. One detoxify mechanism was the exclusion of excessive copper from cells themselves.

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Aznar, J. C., M. Richer-Laflèche, C. Bégin et Y. Bégin. « Lead Exclusion and Copper Translocation in Black Spruce Needles ». Water, Air, and Soil Pollution 203, n^o 1-4 (11 février 2009) : 139–45. http://dx.doi.org/10.1007/s11270-009-9997-8.

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Piscicchia, Kristian, Aidin Amirkhani, Sergio Bartalucci, Sergio Bertolucci, Massimiliano Bazzi, Mario Bragadireanu, Michael Cargnelli et al. « High Precision Test of the Pauli Exclusion Principle for Electrons ». Condensed Matter 4, n^o 2 (2 mai 2019) : 45. http://dx.doi.org/10.3390/condmat4020045.

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The VIP-2 experiment aims to perform high precision tests of the Pauli Exclusion Principle for electrons. The method consists in circulating a continuous current in a copper strip, searching for the X radiation emission due to a prohibited transition (from the 2p level to the 1s level of copper when this is already occupied by two electrons). VIP already set the best limit on the PEP violation probability for electrons 1 2 β 2 < 4.7 × 10 − 29 , the goal of the upgraded VIP-2 (VIolation of the Pauli Exclusion Principle-2) experiment is to improve this result of two orders of magnitude at least. The experimental apparatus and the results of the analysis of a first set of collected data will be presented.

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Bunton, Tracie E. « Exclusion of Copper from Altered Hepatocytes in White Perch (Morone americana) with Hepatic Copper Storage ». Journal of Wildlife Diseases 31, n^o 1 (janvier 1995) : 99–103. http://dx.doi.org/10.7589/0090-3558-31.1.99.

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Piscicchia, Kristian, Johann Marton, Sergio Bartalucci, Massimiliano Bazzi, Sergio Bertolucci, Mario Bragadireanu, Michael Cargnelli et al. « VIP-2 —High-Sensitivity Tests on the Pauli Exclusion Principle for Electrons ». Entropy 22, n^o 11 (22 octobre 2020) : 1195. http://dx.doi.org/10.3390/e22111195.

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The VIP collaboration is performing high sensitivity tests of the Pauli Exclusion Principle for electrons in the extremely low cosmic background environment of the underground Gran Sasso National Laboratory INFN (Italy). In particular, the VIP-2 Open Systems experiment was conceived to put strong constraints on those Pauli Exclusion Principle violation models which respect the so-called Messiah–Greenberg superselection rule. The experimental technique consists of introducing a direct current in a copper conductor, and searching for the X-rays emission coming from a forbidden atomic transition from the L shell to the K shell of copper when the K shell is already occupied by two electrons. The analysis of the first three months of collected data (in 2018) is presented. The obtained result represents the best bound on the Pauli Exclusion Principle violation probability which fulfills the Messiah–Greenberg rule.

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Chromiński, Mikołaj, Anna Zieleniewska, Maksymilian Karczewski et Dorota Gryko. « Porphyrins as substrates in CuAAC — exclusion of unwanted copper insertion into the macrocyclic core ». Journal of Porphyrins and Phthalocyanines 18, n^o 04 (avril 2014) : 267–81. http://dx.doi.org/10.1142/s1088424613501216.

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Unwanted copper insertion into a free base porphyrin starting material during Cu -catalyzed [1,3] azide-alkyne dipolar cycloaddition ( CuAAC ) is not observed when using (1,10-phenanthroline)-bis(triphenylphosphine)copper(I) nitrate as a catalyst. Reactions give 1,4-disubstituted 1,2,3-triazoles in good yields for a broad range of porphyrins. 1,5-Disubstituted 1,2,3-triazole cycloadducts can be generated in the presence of Cp*RuCl ( COD ).

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Celis-Plá, Paula S. M., Fernanda Rodríguez-Rojas, Lorena Méndez, Fabiola Moenne, Pamela T. Muñoz, M. Gabriela Lobos, Patricia Díaz et al. « MAPK Pathway under Chronic Copper Excess in Green Macroalgae (Chlorophyta) : Influence on Metal Exclusion/Extrusion Mechanisms and Photosynthesis ». International Journal of Molecular Sciences 20, n^o 18 (13 septembre 2019) : 4547. http://dx.doi.org/10.3390/ijms20184547.

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There is currently no information regarding the role that whole mitogen activated protein kinase (MAPK) pathways play in counteracting environmental stress in photosynthetic organisms. To address this gap, we exposed Ulva compressa to chronic levels of copper (10 µM) specific inhibitors of Extracellular Signal Regulated Kinases (ERK), c-Jun N-terminal Kinases (JNK), and Cytokinin Specific Binding Protein (p38) MAPKs alone or in combination. Intracellular copper accumulation and photosynthetic activity (in vivo chlorophyll a fluorescence) were measured after 6 h, 24 h, 48 h, and 6 days of exposure. By day 6, when one (except JNK) or more of the MAPK pathways were inhibited under copper stress, there was a decrease in copper accumulation compared with algae exposed to copper alone. When at least two MAPKs were blocked, there was a decrease in photosynthetic activity expressed in lower productivity (ETRmax), efficiency (αETR), and saturation of irradiance (EkETR), accompanied by higher non-photochemical quenching (NPQmax), compared to both the control and copper-only treatments. In terms of accumulation, once the MAPK pathways were partially or completely blocked under copper, there was crosstalk between these and other signaling mechanisms to enhance metal extrusion/exclusion from cells. Crosstalk occurred among MAPK pathways to maintain photosynthesis homeostasis, demonstrating the importance of the signaling pathways for physiological performance. This study is complemented by a parallel/complementary article Rodríguez-Rojas et al. on the role of MAPKs in copper-detoxification.

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Fu, Lei, Chen Chen, Bin Wang, Xishi Zhou, Shuhuan Li, Pan Guo, Zhenguo Shen, Guiping Wang et Yahua Chen. « Differences in Copper Absorption and Accumulation between Copper-Exclusion and Copper-Enrichment Plants : A Comparison of Structure and Physiological Responses ». PLOS ONE 10, n^o 7 (24 juillet 2015) : e0133424. http://dx.doi.org/10.1371/journal.pone.0133424.

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Veronika, Tangke, Bohari Yusuf et Rahmat Gunawan. « DECREASED LEVEL OF METAL IONS OF COPPER (CU) IN THE ELECTROPLATING INDUSTRY WASTE WATER USING ELECTRODEPOSITION METHOD ». JURNAL KIMIA MULAWARMAN 16, n^o 1 (29 novembre 2018) : 60. http://dx.doi.org/10.30872/jkm.v16i1.415.

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The reduction of copper concentration in the electroplating industry wastewater by electrodeposition method by means of Atomic Absorption Spectrophotometer (AAS). The result of research showed that degradation and is big of elimination percent of copper metal have with the effect of time contact and voltage at optimum hence in getting results of final concentration of iron (Fe) successive plate 4,02 ppm and 2,84 ppm of concentration early 35,86 ppm and elimination percent of exclusion at optimum parameter in getting result successive 88,403 % and 92,069 %. While the results of the final concentration of Aluminium (Al) successive plate 2,38 ppm dan 2,22 ppm of concentration early 35,86 ppm and elimination percent of exclusion at optimum parameter in getting result successive 93,363 % dan 93,814%.

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Nguyen, Trang Q., Joshua E. Kim, Hayley N. Brawley et Paul A. Lindahl. « Chromatographic detection of low-molecular-mass metal complexes in the cytosol of Saccharomyces cerevisiae ». Metallomics 12, n^o 7 (2020) : 1094–105. http://dx.doi.org/10.1039/c9mt00312f.

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Vandenbergh, Joke, Gunter Reekmans, Peter Adriaensens et Thomas Junkers. « Synthesis of sequence-defined acrylate oligomers via photo-induced copper-mediated radical monomer insertions ». Chemical Science 6, n^o 10 (2015) : 5753–61. http://dx.doi.org/10.1039/c5sc02035b.

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Photo-induced copper-mediated radical polymerization is used to synthesize monodisperse sequence defined acrylate oligomers via consecutive single unit monomer insertion reactions and intermediate purification of the compounds by column or preparative recycling size exclusion chromatography.

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Areshina, N. S., А. G. Kasikov, I. E. Malts et Т. R. Zenkevich. « Recycling of Gas Cleaning Off-test Products when Producing Copper at "Kolskaya GMK" JSC ». Ecology and Industry of Russia 22, n^o 12 (4 décembre 2018) : 4–9. http://dx.doi.org/10.18412/1816-0395-2018-12-4-9.

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The procedures aimed to recycle off-test products of the dust-and-gas phase when producing copper at the industrial complex “Severonikel” of “Kolskaya GMK” JSC have been developed. Introduction of the proposed procedures into production will allow substantial reducing the environmental impact from cathode copper manufacture thanks to decrease of the gas phase dust content and exclusion of off-test products from the technological cycle. The advantages of the proposed procedures are low capital expenditures during implementation, increase in complexity of raw material usage, and fitness of the recycling procedures to the main technology of cathode copper manufacture.

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Colzi, Ilaria, Sara Pignattelli, Elisabetta Giorni, Alessio Papini et Cristina Gonnelli. « Linking root traits to copper exclusion mechanisms in Silene paradoxa L. (Caryophyllaceae) ». Plant and Soil 390, n^o 1-2 (5 janvier 2015) : 1–15. http://dx.doi.org/10.1007/s11104-014-2375-3.

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Wright, Gareth S. A., S. Samar Hasnain et J. Günter Grossmann. « The structural plasticity of the human copper chaperone for SOD1 : insights from combined size-exclusion chromatographic and solution X-ray scattering studies ». Biochemical Journal 439, n^o 1 (14 septembre 2011) : 39–44. http://dx.doi.org/10.1042/bj20110948.

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The incorporation of copper into biological macromolecules such as SOD1 (Cu,Zn superoxide dismutase) is essential for the viability of most organisms. However, copper is toxic and therefore the intracellular free copper concentration is kept to an absolute minimum. Several proteins, termed metallochaperones, are charged with the responsibility of delivering copper from membrane transporters to its intracellular destination. The CCS (copper chaperone for SOD1) is the major pathway for SOD1 copper loading. We have determined the first solution structure of hCCS (human CCS) by SAXS (small-angle X-ray scattering) in conjunction with SEC (size-exclusion chromatography). The findings of the present study highlight the importance of this combined on-line chromatographic technology with SAXS, which has allowed us to unambiguously separate the hCCS dimer from other oligomeric and non-physiological aggregated states that would otherwise adversely effect measurements performed on bulk solutions. The present study exposes the dynamic molecular conformation of this multi-domain chaperone in solution. The metal-binding domains known to be responsible for the conveyance of copper to SOD1 can be found in positions that would expedite this movement. Domains I and III of a single hCCS monomer are able to interact and can also move into positions that would facilitate initial copper binding and ultimately transfer to SOD1. Conversely, the interpretation of our solution studies is not compatible with an interaction between these domains and their counterparts in an hCCS dimer. Overall, the results of the present study reveal the plasticity of this multi-domain chaperone in solution and are consistent with an indispensable flexibility necessary for executing its dual functions of metal binding and transfer.

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Shi, H., S. Bartalucci, M. Bazzi, S. Bertolucci, A. M. Bragadireanu, M. Cargnelli, A. Clozza et al. « Search for the violation of Pauli Exclusion Principle at LNGS ». EPJ Web of Conferences 182 (2018) : 02118. http://dx.doi.org/10.1051/epjconf/201818202118.

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In the VIP (VIolation of Pauli exclusion principle) and its follow-up VIP- 2 experiments at the Laboratori Nazionali del Gran Sasso, we test the validity of the Pauli Exclusion Principle, by searching for x-rays from copper atomic transitions from a 2p orbit electron to the ground state which is already occupied by two electrons. Such transitions are prohibited by the Pauli Exclusion Principle. The physics run of the VIP-2 experiment started in late 2016 and will collect data for three years. From the first data taking period of two months we have obtained a new limit better than the VIP result from three years of running. In this article we present the published first physics result from the VIP-2 experiment and discuss about the future perspectives.

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BARTALUCCI, S., S. BERTOLUCCI, M. BRAGADIREANU, M. CARGNELLI, M. CATITTI, C. CURCEANU (PETRASCU), S. DI MATTEO et al. « THE VIP (VIOLATION OF THE PAULI EXCLUSION PRINCIPLE) EXPERIMENT ». International Journal of Quantum Information 05, n^o 01n02 (février 2007) : 299–304. http://dx.doi.org/10.1142/s0219749907002785.

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The Pauli Exclusion Principle (PEP) represents one of the fundamental principles of the modern physics and our comprehension of the surrounding matter is based on it. Even if today there are no compelling reasons to doubt its validity, it still spurs a lively debate on its limits, as testified by the abundant contributions found in the literature and in topical conferences. We present a method of searching for possible small violations of PEP for electrons, through the search for "anomalous" X-ray transitions in copper atoms, produced by "fresh" electrons which can decay in a Pauli-forbidden transition to the 1s level, already occupied by two electrons. The VIP Experiment has the scientific goal to improve by four orders of magnitude the present limit on the probability of PEP violation for electrons, bringing it into the 10-30–10-31 region. Preliminary results, together with future plans, are presented.

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Mandell, Jonathan B., Feiqi Lu, Matthew Fisch, Jan H. Beumer, Jianxia Guo, Rebecca J. Watters et Kurt R. Weiss. « Combination Therapy with Disulfiram, Copper, and Doxorubicin for Osteosarcoma : In Vitro Support for a Novel Drug Repurposing Strategy ». Sarcoma 2019 (11 juillet 2019) : 1–9. http://dx.doi.org/10.1155/2019/1320201.

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Although many cancer cells have significantly higher copper concentrations compared with normal cells and tissues, the role of copper in cancer biology and metastatic disease remains poorly understood. Here, we study the importance of copper in osteosarcoma, which frequently metastasizes to the lungs and is often chemoresistant. K12 and K7M2 are murine OS cells with differing metastatic phenotypes: K7M2 is highly metastatic, whereas K12 is much less so. Intracellular copper levels were determined using atomic absorption. Copper transporters were quantified by qPCR. Cytotoxicity of doxorubicin, disulfiram, and copper(II) chloride was assessed with a cell viability fluorescence stain. Additionally, K7M2 viable cell counts were determined by trypan blue exclusion staining after 72 hours of treatment. Copper levels were found to be significantly higher in K12 OS cells than in K7M2 cells. qPCR showed that K12 cells upregulate the copper influx pump CTR1 and downregulate the copper efflux pump ATP7A compared to K7M2 OS cells. Combination treatment of copper chloride (50 nM) with disulfiram (80 nM) was only cytotoxic to K12 cells. Triple treatment with doxorubicin, disulfiram, and copper displayed potent and durable cytotoxicity of highly metastatic K7M2 cells. We demonstrate here that murine OS cell lines differing in metastatic potential also vary in endogenous copper levels and regulation. Additionally, these differences in copper regulation may contribute to selective cytotoxicity of K12 cells by extremely low doses of copper-potentiated disulfiram. The combination of doxorubicin, disulfiram, and copper should be explored as a therapeutic strategy against OS metastases.

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Yogesh, Chendake, Mahajan-Tatpate Pallavi, Dhume Supriya et Chavan Sachin. « Acid-Modified ZnO Nanoparticles Embedded Polysulfone Membranes for Separation of Copper from Industrial Wastewater ». International Journal of Membrane Science and Technology 9 (9 octobre 2022) : 67–76. http://dx.doi.org/10.15379/2410-1869.2022.07.

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Copper is one of the crucial materials for the biological activity of human beings and is known for antimicrobial properties during wound management. Hence its presence in the effluent is overlooked although it is reported to be detrimental at higher concentrations. Its effect on humans varies from simple dizziness, diarrhea to liver/kidney damage, etc. Various techniques are reported for separation of these toxic pollutants from effluent. This article focuses on development of polysulfone-based membranes with use of additives: polyethylene glycol (PEG) and ZnO nanoparticles (NPs) (nascent and modified with HCl) for separation of copper from effluent by Donnan Exclusion principle. The incorporation of acid treated ZnO NPs in membrane matrix provides surface charge to membrane. This results in repulsive interaction with copper salts from process which retained in retentate as per Donnan exclusion principle. The membrane formed with 40% PSF- 0.8% ZnO NPs shows the rejection of copper up to 40%, which raises to 61% when instead of nascent NPs, HCl treated NPs were used. The rejection efficiency of the membrane raises up to 90% when PEG was used along with PSF and ZnO NPs (acid treated). The use of modified NPs in membrane matrix has strong impact on membrane morphology and rejection efficiency. The modification of surface charge properties and morphological distribution of NPs is supported by FTIR and EDX. Further the separation works upon physical distribution of NPs, which would help to maintain the stability properties of PSF based membrane enhancing its applicability in actual process conditions.

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Rudolph, Tobias, Sarah Crotty, Ulrich S. Schubert et Felix H. Schacher. « Star-shaped poly(2-ethyl-2-oxazoline) featuring a porphyrin core : synthesis and metal complexation ». e-Polymers 15, n^o 4 (1 juillet 2015) : 227–35. http://dx.doi.org/10.1515/epoly-2015-0041.

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AbstractWe demonstrate the synthesis of star-shaped poly(2-ethyl-2-oxazoline) featuring a porphyrin core starting from alkyne-functionalized porphyrin ([TPP-TB]4) and azide-functionalized poly(2-ethyl-2-oxazoline) (PEtOx-N3) via copper-catalyzed azide-alkyne cycloaddition (CuAAC). The porphyrin core was further utilized for the complexation of either copper or iron within the central cavity. The obtained materials were investigated using a combination of nuclear magnetic resonance spectroscopy, fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, size-exclusion chromatography, and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. In the case of copper, the inclusion of the metal ion was achieved in a one-pot reaction during the CuAAC reaction for attaching the PEtOx-N3 arms.

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PIETREANU, D., S. BARTALUCCI, S. BERTOLUCCI, M. BRAGADIREANU, M. CARGNELLI, M. CATITTI, C. CURCEANU PETRASCU et al. « VIP EXPERIMENT : NEW EXPERIMENTAL LIMIT ON PAULI EXCLUSION PRINCIPLE VIOLATION BY ELECTRONS ». International Journal of Modern Physics A 24, n^o 02n03 (30 janvier 2009) : 506–10. http://dx.doi.org/10.1142/s0217751x0904395x.

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The VIP (Violation of the Pauli Exclusion Principle) experiment is investigating one of the basic principles of modern physics, searching for anomalous X-rays emitted by copper atoms in a conductor: any detection of these anomalous X-rays would mark a Pauli forbidden transition. VIP is currently taking data at the Gran Sasso underground laboratories, and its scientific goal is to improve by three-four orders of magnitude the previous limit on the probability of Pauli violating transitions, bringing it into the 10-29÷-30 region. The new experimental results, together with future plans, are presented.

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CHAN, MINH-TIEN, et N. M. PLAKIDA. « ELECTRON–PHONON MECHANISM OF SUPERCONDUCTIVITY IN THE TWO-BAND EMERY MODEL ». Modern Physics Letters B 06, n^o 21 (10 septembre 1992) : 1309–18. http://dx.doi.org/10.1142/s0217984992001009.

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The electron–phonon mechanism of superconducting pairing in the two-band Emery model on a square lattice is considered. On the basis of the equation of motion the self-consistent system of equations for the matrix electron Green function is obtained. The dependence of the superconducting transition temperature T c on the concentration of holes is calculated. It is shown that due to the exclusion of double occupancy of copper sites the maximum T c occurs at the concentrations of holes n ≈ 0.8 and n ≈ 2.3, which correspond to the Van Hove singularities in copper and oxygen band, respectively.

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Napolitano, Fabrizio, Sergio Bartalucci, Sergio Bertolucci, Massimiliano Bazzi, Mario Bragadireanu, Cesidio Capoccia, Michael Cargnelli et al. « Testing the Pauli Exclusion Principle with the VIP-2 Experiment ». Symmetry 14, n^o 5 (27 avril 2022) : 893. http://dx.doi.org/10.3390/sym14050893.

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Violations of the Pauli Exclusion Principle (PEP), albeit small, could be motivated by physics beyond the Standard Model, ranging from violation of Lorentz invariance to extra space dimensions. This scenario can be experimentally constrained through dedicated, state-of-the-art X-ray spectroscopy, searching for a forbidden atomic transition from the L shell to the K shell already occupied by two electrons. The VIP-2 Experiment located at the underground Gran Sasso National Laboratories of INFN (Italy) tests PEP violations by introducing new electrons via a direct current in a copper conductor, measuring the X-ray energies through a silicon drift detector. Bayesian and frequentist analyses of approximately six months of data taken with the fully operational setup is presented, setting the strongest limit to date on the PEP violation shown by the VIP collaboration. The upper bound on PEP violation are placed at 90% CL β2/2≤6.8×10−42 with the Bayesian approach, and β2/2≤7.1×10−42 with the frequentist CLs technique.

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Twiss, M. R., P. M. Welbourn et E. Schwärtzel. « Laboratory selection for copper tolerance in Scenedesmus acutus (Chlorophyceae) ». Canadian Journal of Botany 71, n^o 2 (1 février 1993) : 333–38. http://dx.doi.org/10.1139/b93-035.

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Through repeated subculturing of a Cu-sensitive population (X72) of the microalga Scenedesmus acutus f. alternans Hortobagyi (Chlorophyceae) in sublethal concentrations of copper (2.4 μM), a Cu-tolerant population (XCu) was derived. Tolerance to copper, measured as yield over 10 days in batch culture with 0.79 μM Cu, was constitutive. Adsorbed copper as a percentage of total copper was 77, 63, and 40% for a Cu-tolerant field isolate (B-4), XCu, and X72, respectively, during 16 h exposure to 10 μM Cu. These percentages were positively correlated with the level of copper tolerance displayed by the algal strains, i.e., B-4 > XCu > X72. Cells of XCu adsorbed twice as much copper per unit surface area in comparison with the parent strain (X72 = 13.1 amol∙μm−2; XCu = 26.0 amol∙μm−2). Exclusion of copper from the cell interior due to the high Cu-adsorptive capacity of the cell surface is suggested as the primary tolerance mechanism for the XCu strain. No metal cotolerance was demonstrated by XCu when assayed at 0.85 μM Co or Ni. Smaller cell size of the XCu but similar growth rate in comparison with the parent population X72 suggests that selection of a cell type from the original population may have occurred as a result of the copper challenge. Key words: algae, copper, metal tolerance, selection, toxicity.

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Larner, Fiona, Catriona A. McLean, Alex N. Halliday et Blaine R. Roberts. « Copper Isotope Compositions of Superoxide Dismutase and Metallothionein from Post-Mortem Human Frontal Cortex ». Inorganics 7, n^o 7 (7 juillet 2019) : 86. http://dx.doi.org/10.3390/inorganics7070086.

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The natural copper isotopic compositions of superoxide dismutase and metallothionein from six post-mortem human frontal cortices were determined using a combination of size exclusion protein liquid chromatography, followed by anion exchange chromatography and multiple collector inductively-coupled plasma mass spectrometry. Superoxide dismutase was enriched in the heavier 65Cu relative to the metallothionein fraction in all specimen pairs. The isotopic compositions were independent of copper content. This finding provides evidence that nitrogen ligands in protein copper binding sites will be enriched in heavy metal isotopes, and sulphur ligands will preferentially incorporate lighter isotopes in vivo. This in turn has implications for understanding isotopic distributions within different components in the body and the dominant ligands in different tissues. Differences in Cu isotope distributions between the two proteins were seen between Alzheimer’s disease and healthy control samples, when normalised for sex.

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Karzov, I., O. Shornikova, S. Filimonov, A. Malakho et V. Avdeev. « Cu-Expanded Graphite Composite Material Preparation and Thermal Properties ». Eurasian Chemico-Technological Journal 19, n^o 3 (30 septembre 2017) : 273. http://dx.doi.org/10.18321/ectj671.

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A composite material based on expanded graphite (EG) and copper compounds was obtained by natural graphite oxidation with 95% nitric acid, copper (II) nitrate and granular carbamide addition with further rapid heat treatment at three different exfoliation temperatures: 800, 1000 and 1200 °С. It was found that the composition of copper containing graphite material depends on the temperature and the atmosphere of thermal expansion. The formation of copper oxides can be eliminated if rapid heat treatment is conducted in nitrogen at 1200 °С. Thermal conductive properties: thermal diffusivity and specific heat capacity of obtained Cu-expanded graphite samples were measured. It was revealed that the dependence of thermal conductivity (TC) of Cu-graphite material has non-linear character in the studied range of copper content. The incorporation of 3% copper into expanded graphite allows to increase its thermal conductivity by 20% while the further Cu content growth leads to the TC decrease from 6 to 4.5 W/(m∙K). The specific heat capacity is constant at ω(Cu)<3% and reduces in the range (3‒8)% Cu. The advantage of proposed technique of Cu-expanded graphite materials preparation is exclusion graphite intercalation compounds hydrolysis step with further drying because of carbamide addition.

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Lee, M. R., et J. A. Correa. « Copper mine tailings disposal : consequences for the interstitial polychaete Saccocirrus sonomacus (Canalipalpata : Protodrilida) ». Journal of the Marine Biological Association of the United Kingdom 84, n^o 3 (24 mai 2004) : 603–6. http://dx.doi.org/10.1017/s0025315404009610h.

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The hypothesis investigated in this paper is that the interstitial polychaete Saccocirrus sonomacus is excluded from beaches impacted by tailing disposal as a result of the blocking of the interstitial space and not by a response to the toxicity of elevated copper concentrations. Field evidence suggested that abundances of S. sonomacus on beaches where they would be expected to occur under natural conditions are lower when a beach has received a significant amount of tailings. In choice experiments, S. sonomacus always preferred an open coarse sand matrix to one where the interstitial spaces had been blocked by fine sand (a tailings substitute). Using invitro bioassays, we found that the LC50 for S. sonomacus with copper was 44 μg Cu l−1, this being higher than the values of interstitial labile copper measured on the beaches investigated in this study. We therefore accept the hypothesis of a physically mediated exclusion rather than a toxically mediated one.

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Lockitch, G., A. C. Halstead, L. Wadsworth, G. Quigley, L. Reston et B. Jacobson. « Age- and sex-specific pediatric reference intervals and correlations for zinc, copper, selenium, iron, vitamins A and E, and related proteins. » Clinical Chemistry 34, n^o 8 (1 août 1988) : 1625–28. http://dx.doi.org/10.1093/clinchem/34.8.1625.

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Abstract Age- and sex-specific reference intervals based on the 0.025 and 0.975 fractiles of data derived from a healthy pediatric population are presented for zinc, copper, selenium, iron, ferritin, retinol, alpha-tocopherol, and related analytes in serum. Age was an important covariate for copper, selenium, retinol, and tocopherol, and ferritin in boys. Strong correlations were found between retinol and retinol-binding protein, prealbumin (transthyretin), alpha-tocopherol, and selenium. Tocopherol was highly correlated with both cholesterol and triglycerides. We found no relationship between serum zinc and either retinol or retinol-binding protein. Despite exclusion of children in whom anemia, microcytosis, or variant hemoglobins were found, the 0.025 fractile for iron in several age groups was even less than the concentration considered to indicate poor iron nutritional status.

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Zhang, Hao, Yang Liu, Fenglian Sun, Gaofang Ban et Jiajie Fan. « Effects of nano-copper particles on the properties of Sn58Bi composite solder pastes ». Microelectronics International 34, n^o 1 (3 janvier 2017) : 40–44. http://dx.doi.org/10.1108/mi-02-2016-0013.

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Purpose This paper aimed to investigate the effects of nano-copper particles on the melting behaviors, wettability and defect formation mechanism of the Sn58Bi composite solder pastes. Design/methodology/approach In this paper, the mechanical stirring method was used to get the nano-composite solder pastes. Findings Experimental results indicated that the addition of 3 wt.% (weight percentage) 50 nm copper particles showed limited effects on the melting behaviors of the Sn58Bi composite solder paste. The spreading rate of the Sn58Bi composite solder paste showed a decreasing trend with the increase of the weight percentage of 50 nm copper particles from 0 to 3 wt.%. With the addition of copper particles of diameters 50 nm, 500 nm or 6.5 μm into the Sn58Bi solder paste, the porosities of the three types of solder pastes showed a similar trend. The porosity increased with the increase of the weight percentage of copper particles. Based on the experimental results, a model of the void formation mechanism was proposed. During reflow, the copper particles reacted with Sn in the matrix and formed intermetallic compounds, which gathered around the voids produced by the volatilization of flux. The exclusion of the voids was suppressed and eventually led to the formation of defects. Originality/value This study provides an optimized material for the second and third level packaging. A model of the void formation mechanism was proposed.

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Armer, Jane, et Christian De Goede. « How to use tests for disorders of copper metabolism ». Archives of disease in childhood - Education & ; practice edition 102, n^o 6 (27 juillet 2017) : 319–27. http://dx.doi.org/10.1136/archdischild-2016-310960.

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In paediatrics, one of our main aims in the diagnostic process is to identify any treatable conditions. The copper metabolism disorder Wilson’s disease (WD) is one such condition that is caused by mutations in the ATP7B gene. Delay in treatment could result in irreversible disability or even death. Although liver disease is the most common presenting feature in children, some children may initially present with a subtle neurological presentation only. In patients presenting with dystonia, tremor, dysarthria or with a deterioration in school performance, there should be a high index of suspicion for WD. However, the differential of these clinical presentations is wide and exclusion of WD is difficult. No single diagnostic test can exclude WD and each of the biochemical tests has limitations. In this article, we discuss copper metabolism disorders including WD and Menke’s disease. We then discuss the available diagnostic tests and how to investigate children for these rare disorders.

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Téllez, Carlos M., Kristen P. Gaus, David W. Graham, Robert G. Arnold et Roberto Z. Guzman. « Isolation of Copper Biochelates fromMethylosinus trichosporium OB3b and Soluble Methane Monooxygenase Mutants ». Applied and Environmental Microbiology 64, n^o 3 (1 mars 1998) : 1115–22. http://dx.doi.org/10.1128/aem.64.3.1115-1122.1998.

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ABSTRACT Methylosinus trichosporium OB3b produces an extracellular copper-binding ligand (CBL) with high affinity for copper. Wild-type cells and mutants that express soluble methane monooxygenase (sMMO) in the presence and absence of copper (sMMOc) were used to obtain cell exudates that were separated and analyzed by size exclusion high-performance liquid chromatography. A single chromatographic peak, when present, contained most of the aqueous-phase Cu(II) present in the culture medium. In mutant cultures that were unable to acquire copper, extracellular CBL accumulated to high levels both in the presence and in the absence of copper. Conversely, in wild-type cultures containing 5 μM Cu(II), extracellular CBL was maintained at a low, steady level during exponential growth, after which the external ligand was rapidly consumed. When Cu(II) was omitted from the growth medium, the wild-type organism produced the CBL at a rate that was proportional to cell density. After copper was added to this previously Cu-deprived culture, the CBL and copper concentrations in the medium decreased at approximately the same rate. Apparently, the extracellular CBL was produced throughout the period of cell growth, in the presence and absence of Cu(II), by both the mutant and wild-type cultures and was reinternalized or otherwise utilized by the wild-type cultures when it was bound to copper. CBL produced by the mutant strain facilitated copper uptake by wild-type cells, indicating that the extracellular CBLs produced by the mutant and wild-type organisms are functionally indistinguishable. CBL from the wild-type strain did not promote copper uptake by the mutant. The molecular weight of the CBL was estimated to be 500, and its association constant with copper was 1.4 × 1016 M−1. CBL exhibited a preference for copper, even in the presence of 20-fold higher concentrations of nickel. External complexation may play a role in normal copper acquisition by M. trichosporium OB3b. The sMMOcphenotype is probably related to the mutant’s inability to take up CBL-complexed copper, not to a defective CBL structure.

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Hung, Ya Hui, Meredith J. Layton, Ilia Voskoboinik, Julian F. B. Mercer et James Camakaris. « Purification and membrane reconstitution of catalytically active Menkes copper-transporting P-type ATPase (MNK ; ATP7A) ». Biochemical Journal 401, n^o 2 (21 décembre 2006) : 569–79. http://dx.doi.org/10.1042/bj20060924.

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The MNK (Menkes disease protein; ATP7A) is a major copper- transporting P-type ATPase involved in the delivery of copper to cuproenzymes in the secretory pathway and the efflux of excess copper from extrahepatic tissues. Mutations in the MNK (ATP7A) gene result in Menkes disease, a fatal neurodegenerative copper deficiency disorder. Currently, detailed biochemical and biophysical analyses of MNK to better understand its mechanisms of copper transport are not possible due to the lack of purified MNK in an active form. To address this issue, we expressed human MNK with an N-terminal Glu-Glu tag in Sf9 [Spodoptera frugiperda (fall armyworm) 9] insect cells and purified it by antibody affinity chromatography followed by size-exclusion chromatography in the presence of the non-ionic detergent DDM (n-dodecyl β-D-maltopyranoside). Formation of the classical vanadate-sensitive phosphoenzyme by purified MNK was activated by Cu(I) [EC50=0.7 μM; h (Hill coefficient) was 4.6]. Furthermore, we report the first measurement of Cu(I)-dependent ATPase activity of MNK (K0.5=0.6 μM; h=5.0). The purified MNK demonstrated active ATP-dependent vectorial 64Cu transport when reconstituted into soya-bean asolectin liposomes. Together, these data demonstrated that Cu(I) interacts with MNK in a co-operative manner and with high affinity in the sub-micromolar range. The present study provides the first biochemical characterization of a purified full-length mammalian copper-transporting P-type ATPase associated with a human disease.

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Gray, Lawrence W., Theodros Z. Kidane, Anh Nguyen, Sheryl Akagi, Kristina Petrasek, Yu-Ling Chu, Anthony Cabrera, Katherine Kantardjieff, Andrew Z. Mason et Maria C. Linder. « Copper proteins and ferroxidases in human plasma and that of wild-type and ceruloplasmin knockout mice ». Biochemical Journal 419, n^o 1 (13 mars 2009) : 237–45. http://dx.doi.org/10.1042/bj20081983.

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In the blood plasma of humans and rats, ceruloplasmin is the major copper-binding protein and ferroxidase, accounting for 70% of the copper present in the plasma, with the rest binding primarily to albumin and a macroglobulin. Systematic studies with fresh plasma were carried out to compare what occurs in the mouse. C57BL6 mice had half as much copper and pPD (p-phenylene diamine) oxidase activity as humans and rats, 20–40% as much ferroxidase activity as humans (determined using three different assays) and less inhibition by azide. Plasma from ceruloplasmin knockout mice had no pPD oxidase activity, but retained >50% ferroxidase activity (which was not as affected by azide). Modelling of mouse ceruloplasmin against the known X-ray structure of human ceruloplasmin indicated subtle but potentially significant changes in the pPD- and azide-binding sites. Purification and in-gel assays after native PAGE confirmed that mouse ceruloplasmin had ferroxidase activity but revealed an additional ferroxidase in ceruloplasmin knockout mouse plasma, which is also seen in size-exclusion chromatography. In the wild-type mouse, the ‘ceruloplasmin’ peak contained ∼55% of the total copper, but ceruloplasmin knockout plasma exposed a major additional peak (180 kDa) which co-eluted with ferroxidase activity. Two other ferroxidases (700 and 2000 Da) were also detected in mouse and human plasma. Mammalian blood thus contains copper components and ferroxidases not reported previously.

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Nielsen, Hanne D., Colin Brownlee, Susana M. Coelho et Murray T. Brown. « Inter-population differences in inherited copper tolerance involve photosynthetic adaptation and exclusion mechanisms in Fucus serratus ». New Phytologist 160, n^o 1 (22 août 2003) : 157–65. http://dx.doi.org/10.1046/j.1469-8137.2003.00864.x.

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Reza, Tia, Ariadi Ariadi et Yusrawati Yusrawati. « COMPARISON OF COPPER LEVELS IN NORMAL PREGNANCY WOMEN AND SEVERE PREECLAMPSIA ». Jurnal Kesehatan Saintika Meditory 5, n^o 1 (10 mai 2022) : 140. http://dx.doi.org/10.30633/jsm.v5i1.1565.

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Hypertension in pregnancy is one of the obstetric complications that cause a lot of morbidity and mortality in the field obstetrics, in addition to bleeding and infection. The incidence of severe preeclampsia is only 5-10% of all pregnancies but is a major cause of maternal and fetal death and is a major contributor to preterm labor. It is currently estimated that severe preeclampsia accounts for 50,000 deaths annually worldwide, in addition to the presence of this disease will increase the need for intensive neonatal care. The purpose of this research is to determine the difference in copper concentration in normal pregnant women with pregnant women with severe preeclampsia. This research is a diagnostic research with approach used is cross sectional study in maternity hospital room of Obstetrics and Gynecology Department of Faculty of Medicine Universitas Baiturrahmah since September 2016-March 2017. Obtained sample of 60 people who meet inclusion and exclusion criteria. The calculation is done by taking blood samples of patients and examined the level of copper. Data analysis was done univariant and bivariate by using T dependent test. there were significant differences in copper levels in patients with severe preeclampsia and normal pregnancy, where the p value <0.05, and the mean test with 95% confidence level was between 0.767-1.023 at 0.895. This means there is a significant difference in copper levels in severe preeclampsia and normal pregnancy. There were significant differences in copper levels in patients with severe preeclampsia and normal pregnancy.Keywords: Copper, Preeclampsia.

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Herberg, Yu et Kuckling. « End Group Stability of Atom Transfer Radical Polymerization (ATRP)-Synthesized Poly(N-isopropylacrylamide) : Perspectives for Diblock Copolymer Synthesis ». Polymers 11, n^o 4 (13 avril 2019) : 678. http://dx.doi.org/10.3390/polym11040678.

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Studies on the end group stability of poly(N-isopropylacrylamide) during the atom transfer radical polymerization (ATRP) process are presented. Polymerization of N-isopropylacrylamide was conducted in different solvents using a copper(I) chloride/Me6Tren catalyst complex. The influence of the ATRP solvent as well as the polymer purification process on the end group stability was investigated. For the first time, mass spectrometry results clearly underline the loss of ω end groups via an intramolecular cyclization reaction. Furthermore, an ATRP system based on a copper(I) bromide/Me6Tren catalyst complex was introduced, that showed not only good control over the polymerization process, but also provided the opportunity of block copolymerization of N-isopropylacrylamide with acrylates and other N-substituted acrylamides. The polymers were characterized using 1H-NMR spectroscopy and size exclusion chromatography. Polymer end groups were determined via ESI-TOF mass spectrometry enhanced by ion mobility separation (IMS).

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Ando, Yuko, Shinji Nagata, Schuichi Yanagisawa et Tadakatsu Yoneyama. « Copper in xylem and phloem saps from rice (Oryza sativa) : the effect of moderate copper concentrations in the growth medium on the accumulation of five essential metals and a speciation analysis of copper-containing compounds ». Functional Plant Biology 40, n^o 1 (2013) : 89. http://dx.doi.org/10.1071/fp12158.

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Copper (Cu) is an essential element for cereals, playing important roles as a cofactor of several enzymes. Copper and four other metals (Fe, Mn, Zn and Mo) taken up by roots are efficiently delivered to the shoots via xylem and phloem. Here we investigated the concentrations of Cu, Fe, Mn, Zn and Mo in the xylem and phloem saps as well as in tissues of rice (Oryza sativa L.) seedlings when they were grown under different Cu levels in culture solution. Although the Cu concentrations in the roots and the Mn concentrations in the mature shoot tissues were increased with the increase of the Cu level in the culture solution, the concentrations of Cu and the other four metals in the xylem and phloem saps and the Cu contents in the shoot tissues were only slightly affected by moderate increases in the Cu medium level. The results of our analyses using membrane filtration, size-exclusion chromatography and electrospray ionisation time-of-flight mass spectrometry indicate that Cu in the xylem sap is dominantly complexed by 2′-deoxymugineic acid, whereas Cu in the phloem sap is bound to several compounds, i.e. nicotianamine, histidine and other >3-kDa compounds.

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Castilho, P. Del, J. W. Dalenberg, K. Brunt et A. P. Bruins. « Dissolved Organic Matter, Cadmium, Copper and Zinc in Pig Slurry- and Soil Solution- Size Exclusion Chromatography Fractions ». International Journal of Environmental Analytical Chemistry 50, n^o 2 (avril 1993) : 91–107. http://dx.doi.org/10.1080/03067319308027588.

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Sadžak, Anja, Ignacija Vlašić, Zoran Kiralj, Marijana Batarelo, Nada Oršolić, Maja Jazvinšćak Jembrek, Ines Kušen et Suzana Šegota. « Neurotoxic Effect of Flavonol Myricetin in the Presence of Excess Copper ». Molecules 26, n^o 4 (5 février 2021) : 845. http://dx.doi.org/10.3390/molecules26040845.

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Oxidative stress (OS) induced by the disturbed homeostasis of metal ions is one of the pivotal factors contributing to neurodegeneration. The aim of the present study was to investigate the effects of flavonoid myricetin on copper-induced toxicity in neuroblastoma SH-SY5Y cells. As determined by the MTT method, trypan blue exclusion assay and measurement of ATP production, myricetin heightened the toxic effects of copper and exacerbated cell death. It also increased copper-induced generation of reactive oxygen species, indicating the prooxidative nature of its action. Furthermore, myricetin provoked chromatin condensation and loss of membrane integrity without caspase-3 activation, suggesting the activation of both caspase-independent programmed cell death and necrosis. At the protein level, myricetin-induced upregulation of PARP-1 and decreased expression of Bcl-2, whereas copper-induced changes in the expression of p53, p73, Bax and NME1 were not further affected by myricetin. Inhibitors of ERK1/2 and JNK kinases, protein kinase A and L-type calcium channels exacerbated the toxic effects of myricetin, indicating the involvement of intracellular signaling pathways in cell death. We also employed atomic force microscopy (AFM) to evaluate the morphological and mechanical properties of SH-SY5Y cells at the nanoscale. Consistent with the cellular and molecular methods, this biophysical approach also revealed a myricetin-induced increase in cell surface roughness and reduced elasticity. Taken together, we demonstrated the adverse effects of myricetin, pointing out that caution is required when considering powerful antioxidants for adjuvant therapy in copper-related neurodegeneration.

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Baral, Nilima, Rezwana Haque et Farzana Akonjee Mishu. « Evaluation Serum Copper Levels in Preeclampsia and Healthy Pregnant Women ». BIRDEM Medical Journal 9, n^o 1 (11 janvier 2019) : 18–22. http://dx.doi.org/10.3329/birdem.v9i1.39715.

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Background: Preeclampsia is a fatal medical disorder of pregnancy. It has been associated with adverse course and outcome of the pregnancy resulting in increased maternal and infant mortality and morbidity. As the pathogenesis of preeclampsia is not completely understood, prevention remains a complex issue. In recent times, there has been an increasing prevalence in the incidence of preeclampsia globally. The aim of this study is to determine the states of the copper in pregnant women with preeclampsia. Methods: This case-control study was carried out in the Department of Biochemistry, Mymensingh Medical College, Mymensingh, from July 2013 to June 2014. The subjects were selected on the basis of inclusion and exclusion criteria by purposive method. This study included 73 patients with preeclampsia as case (Gr.I) classified into two subgroups according to the gestational age: Gr.I(a); preeclampsia in the second trimester (n = 35), and Gr.I(b); preeclampsia in the third trimester (n = 38). Copper levels were analyzed and results were compared with 73 apparently healthy pregnant control (Gr.II), and the corresponding gestational age subgroups [Gr.II(a); normal pregnancy of second trimester (n = 35) and Gr.II(b), normal pregnancy of third trimester (n = 38)]. Results: The mean serum copper level was significantly (p<0.001) lower in case group than that of control group. Similar extent of reduction was observed in serum copper level at different gestational age groups of preeclamptic women when compared with corresponding control groups. Conclusion: Estimation of serum copper level should be incorporated in pre eclamptic patients for prevention of complications. Birdem Med J 2019; 9(1): 18-22

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Curceanu, Catalina, Sergio Bartalucci, Angelo Bassi, Sergio Bertolucci, Carolina Berucci, Alexandru Mario Bragadireanu, Michael Cargnelli et al. « Hunting the "impossible atoms" Pauli exclusion principle violation and spontaneous collapse of the wave function at test ». International Journal of Quantum Information 12, n^o 07n08 (novembre 2014) : 1560012. http://dx.doi.org/10.1142/s0219749915600126.

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The Pauli exclusion principle (PEP) and, more generally, the spin-statistics connection, are at the very basis of our understanding of matter, life and Universe. The PEP spurs, presently, a lively debate on its possible limits, deeply rooted in the very foundations of Quantum Mechanics. It is, therefore, extremely important to test the limits of its validity. The Violation of the PEP (VIP) experiment established the best limit on the probability that PEP is violated by electrons, using the method of searching for PEP forbidden atomic transitions in copper. We describe the experimental method, the obtained results, and plans to go beyond the actual limit by upgrading the experimental apparatus. We discuss the possibility of using a similar experimental technique to search for X-rays as a signature of the spontaneous collapse of the wave function predicted by continuous spontaneous localization (CSL) theories.

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Facey, Jordan A., Jake P. Violi, Josh J. King, Chowdhury Sarowar, Simon C. Apte et Simon M. Mitrovic. « The Influence of Micronutrient Trace Metals on Microcystis aeruginosa Growth and Toxin Production ». Toxins 14, n^o 11 (21 novembre 2022) : 812. http://dx.doi.org/10.3390/toxins14110812.

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Microcystis aeruginosa is a widespread cyanobacteria capable of producing hepatotoxic microcystins. Understanding the environmental factors that influence its growth and toxin production is essential to managing the negative effects on freshwater systems. Some micronutrients are important cofactors in cyanobacterial proteins and can influence cyanobacterial growth when availability is limited. However, micronutrient requirements are often species specific, and can be influenced by substitution between metals or by luxury uptake. In this study, M. aeruginosa was grown in modified growth media that individually excluded some micronutrients (cobalt, copper, iron, manganese, molybdenum) to assess the effect on growth, toxin production, cell morphology and iron accumulation. M. aeruginosa growth was limited when iron, cobalt and manganese were excluded from the growth media, whereas the exclusion of copper and molybdenum had no effect on growth. Intracellular microcystin-LR concentrations were variable and were at times elevated in treatments undergoing growth limitation by cobalt. Intracellular iron was notably higher in treatments grown in cobalt-deplete media compared to other treatments possibly due to inhibition or competition for transporters, or due to irons role in detoxifying reactive oxygen species (ROS).

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CURCEANU (PETRASCU), C., S. BARTALUCCI, M. BRAGADIREANU, C. GUARALDO, M. ILIESCU, T. PIETREANU, T. PONTA et al. « EXPERIMENTAL TESTS OF QUANTUM MECHANICS PAULI EXCLUSION PRINCIPLE VIOLATION (THE VIP EXPERIMENT) AND FUTURE PERSPECTIVES ». International Journal of Quantum Information 09, supp01 (janvier 2011) : 145–54. http://dx.doi.org/10.1142/s0219749911007162.

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The Pauli exclusion principle (PEP) is one of the basic principles of modern physics. Being at the very basis of our understanding of matter, as many other fundamental principles it spurs, presently, a lively debate on its possible limits, deeply rooted in the very foundations of Quantum Field Theory. Therefore, it is extremely important to test the limits of its validity. Quon theory provides a suitable mathematical framework of possible violation of PEP, where the violation parameter q translates into a probability of violating PEP. Experimentally, setting a bound on PEP violation means confining the violation parameter to a value very close to either 1 (for bosons) or -1 (for fermions). The VIP (VIolation of the Pauli exclusion principle) experiment established a limit on the probability that PEP is violated by electrons, using the method of searching for PEP forbidden atomic transitions in copper. We describe the experimental method, the obtained results, both in terms of the q-parameter from quon theory and as probability of PEP violation, we briefly discuss them and present future plans to go beyond the actual limit by upgrading the experimental technique using vetoed new spectroscopical fast Silicon Drift Detectors. We also shortly mention the possibility of using a similar experimental technique to search for eventual X-rays, generated in the spontaneous collapse models.

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Roncarati, Francesca, Claudio A. Sáez, Maria Greco, Martha Gledhill, Maria B. Bitonti et Murray T. Brown. « Response differences between Ectocarpus siliculosus populations to copper stress involve cellular exclusion and induction of the phytochelatin biosynthetic pathway ». Aquatic Toxicology 159 (février 2015) : 167–75. http://dx.doi.org/10.1016/j.aquatox.2014.12.009.

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Radaelli, Marta, Elisa Scalabrin, Giuseppa Toscano et Gabriele Capodaglio. « High Performance Size Exclusion Chromatography-Inductively Coupled Plasma-Mass Spectrometry to Study the Copper and Cadmium Complexation with Humic Acids ». Molecules 24, n^o 17 (3 septembre 2019) : 3201. http://dx.doi.org/10.3390/molecules24173201.

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Dissolved organic matter (DOM) plays an important role in the environment by influencing the transport and distribution of organic and inorganic components through different processes: the retention, mobilization, and bio-availability of potentially toxic elements (PTEs). The aim of the present study is to examine the dimensional characterization of humic acids (HA) extracted from soil matrix, as well as to analyze the metal distribution among different ligand classes. The molecular size distribution of the HA extract from soil showed three dimensional classes: 52 KDa, 4.5 KDa, and 900 Da. HPSEC-ICP-MS measurements demonstrated that the dimensional classes, relative to first two fractions, bind the largest part of metals. The complexing capacity of HA was evaluated to assess the pollutants mobility in the environmental system. In particular, cadmium (Cd) and copper (Cu) complexation was investigated due to the great concern regarding their bio-availability and toxicity in natural waters. The complexing capacity of HA solution (20 mg/L) was measured by titration using a high-performance size exclusion chromatography (HP-SEC) coupled to an inductively coupled mass spectrometry (ICP-MS). Results obtained by this technique are compared with those obtained by anodic stripping voltammetry (ASV) to investigate the effects of kinetic lability of complexes on measurements carried by HPSEC-ICP-MS. In this study, results of ligand concentrations and stability constants obtained via the two techniques are assessed considering the detection window associated to the applied analytical methodology. Results obtained using the two analytical techniques showed that Cd is complexed by two classes of ligands. However, the ligand concentration values obtained using the two techniques are different, because the detection window associated to the two methodologies; the complexing capacity, which was obtained as sum of the two classes of ligands, were 33 nmol/L and 9 nmol/L for ASV and HPSEC-ICP-MS, respectively. The copper complexing capacities determined by the two methodologies are comparable: 166 and 139 nmol/L for ASV and HPSEC-ICP-MS, respectively. However, the results of Cu titration differ for the two techniques, highlighting only one class of ligands when ASV was used, and two classes when HPSEC-ICP-MS was employed. Differences on results obtained by the two techniques are explained considering the kinetic lability of complexes; the results show that, differently from previous studies, also Cu complexes can be kinetically labile, if one technique with high reaction time is used, as well some cadmium complexes are sufficient stable to be determined by HPSEC-ICP-MS.

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Jerabek, Andrea S., Kara R. Wall et Christopher D. Stallings. « A practical application of reduced-copper antifouling paint in marine biological research ». PeerJ 4 (14 juillet 2016) : e2213. http://dx.doi.org/10.7717/peerj.2213.

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Biofouling of experimental cages and other field apparatuses can be problematic for scientists and has traditionally been addressed using frequent manual removal (e.g., scraping, scrubbing). Recent environmental restrictions and legislative changes have driven the development of less hazardous antifouling products, making antifouling paint a potential alternative option to manual removal. Consequently, the viability of using these newly developed products as a replacement for the manual cleaning of exclusion cages was experimentally investigated. There were six treatments tested, comprising three with settlement tiles in experimental cages coated with antifouling paint, two with settlement tiles in unpainted experimental cages, and one cage-free suspended tile. The three antifouling treatments comprised two reduced-copper paints (21% Cu2O and 40% Cu2O) and one copper-free, Econea™-based paint (labeled “ecofriendly”). Antifouling paints were assessed for performance of preventing fouling of the cages and whether they elicited local effects on settlement tiles contained within them. All three paints performed well to reduce fouling of the cages during the initial six weeks of the experiment, but the efficacy of “ecofriendly” paint began to decrease during an extended deployment that lasted 14 weeks. The macro-community composition, biomass, and percent cover of settled organism on tiles within cages treated with copper-based paints (21% and 40% concentrations) were indistinguishable from tiles within the manually scrubbed cages. In contrast, settlement to tiles from the “ecofriendly” treatment was different in composition of macro-community and lower in biomass, suggesting the presence of local effects and therefore rendering it unsuitable for use in settlement experiments. The results of this study suggest that reduced-copper paints have the potential to serve as an alternative to manual maintenance, which may be useful for deployments in locations that are difficult to access on a frequent schedule.

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Desmiwarti, Desmiwarti, et Hafni Bachtiar. « EVALUASI KOMPETENSI BIDAN DALAM PEMASANGAN ALAT KONTRASEPSI DALAM RAHIM COPPER T 380A BERDASARKAN UMUR, PENDIDIKAN, PENGALAMAN PEMASANGAN DAN LAMA PRAKTIK DI KOTA PADANG ». JOURNAL OBGIN EMAS 3, n^o 1 (10 janvier 2019) : 37–45. http://dx.doi.org/10.25077/aoj.3.1.37-45.2019.

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Midwives are health providers influential in helping families to choose appropriate contraception for patients. Midwives must have competence in providing midwifery services in particular IUD insertion. This study’s aim was to evaluate the competency of midwives in the insertion of an intrauterine device Copper T 380A based on their age, education, experience of insertion and duration of practice in Padang City. This study was done in puskesmas and private midwivery practice in Padang from September to December 2014 using cross-sectional method on 24 samples who met the inclusion criteria and not exclusion criteria. We conducted interviews and observed how the respondents perform IUD insertion by using a check- list. From this study, there was no significant association between age (p: 0.540, p> 0.05), education (p: 0.439, p> 0.05), experience of insertion (p: 0.472, p> 0.05) and duration of practice (p: 0.505, p> 0.05) with competency of IUD insertion. Most respondents have a good competence in IUD insertion. Part of the checklist the respondents frequently missed out were conseling to the patients and prevention of infection.Keywords: Midwives Competency, IUD insertion, Copper T-380a

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Mathew, Janey Mary, Varughese Philip et Jesty Thomas. « Synthesis, Spectroscopic Characterization, Antibacterial and Short Term in vitro Cytotoxicity Studies of Copper(II) Complexes of Novel Tridentate N,N,S Donor Ligand 2-Benzoylpyridine-N(4),N(4)-(N,N-diethyl-N-methylamine-2,2'-diyl)thiosemicarbazone ». Asian Journal of Chemistry 31, n^o 10 (30 août 2019) : 2269–74. http://dx.doi.org/10.14233/ajchem.2019.22138.

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A tridentate N,N,S-donor ligand, 2-benzoylpyridine-N(4),N(4)-(N,N-diethyl-N-methylamine-2,2'-diyl)thiosemicarbazone (Hbptsc) has been synthesized and characterized by elemental CHN analysis, UV-visible, FT-IR and 1H NMR spectroscopy. Copper(II) complexes of the ligand, Hbptsc synthesized have been characterized by elemental analysis, UV-visible spectra, FTIR spectra and EPR spectroscopic simulation. The complexes hold the stoichiometry of the type [CuLX] where X= Cl (1), NO3 (2), SO4 (3), N3 (4), SCN (5) confirmed by the molar conductivity studies of 10-3 M solutions in DMF at room temperature. The EPR spectra of the complexes recorded in DMF at 77 K shows an axial type spectra with two distinct g-values, g|| and g⊥ indicating a four coordinated planar geometry. The antimicrobial studies of the copper(II) complexes shows an appreciable activity against both gram positive and gram negative bacteria using streptomycin as positive control. The short term in vitro cytotoxicity studies following trypan blue dye exclusion method exhibits pronounced activity against the Dalton’s Lymphoma Ascites tumour cells extruded from the peritoneal cavity of mice.

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Zhang, Zhi-Fan, Richard A. Kennish, Blohowiak Kay A. Youngdahl, Martin L. Hoppe et Richard M. Laine. « Superconducting fibers from organometallic precursors : Part III. Pyrolytic processing of precursor fibers ». Journal of Materials Research 8, n^o 8 (août 1993) : 1777–90. http://dx.doi.org/10.1557/jmr.1993.1777.

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Sixty−70 μm diameter preceramic fibers, extruded from THF solutions containing 1:2:3 stoichiometric mixtures of yttrium, barium, and copper carboxylates, were pyrolytically transformed into ceramic fibers using controlled heating schedules and reactive atmospheres. The objectives of the work reported here were to identify appropriate processing conditions such that during pyrolysis the preceramic fibers would (1) eliminate the organic ligands without pore or void formation, (2) reach full density with a controlled grain size, and (3) form orthorhombic phase, 123 fibers with reasonable mechanical properties. The mechanisms of organic ligand decomposition and loss were examined using mass spectral fragmentation and TGA. Microstructural and phase evolution were correlated with heating schedules and atmospheres, using XRD, DTA, SEM, and limited flux exclusion studies. The mechanisms of decomposition of the spinnable mixtures suggest intermolecular rather than intramolecular decomposition pathways. Different pyrolysis atmospheres were also examined to explore methods of controlling the degradation process. Slow pyrolysis in air followed by oxygen anneals appears to give superior fibers in terms of controlled grain size and phase. The pyrolyzed fibers exhibit the appropriate orthorhombic phase according to x-ray powder diffractometry. Preliminary flux exclusion measurements demonstrate that the fibers are superconducting although the measured δTc is not exceptional.

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EGASHIRA, Naoyoshi, Tetsuya ANAMI et Kazuya OHGA. « Electrochemical detection of aquatic humic substances based on anodic dissolution of a copper electrode in high-performance size-exclusion chromatography. » Analytical Sciences 7, n^o 1 (1991) : 165–67. http://dx.doi.org/10.2116/analsci.7.165.

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Gold, Bronislaw K., Peter W. Alexander, Paul R. Haddad et Zu L. Chen. « Potentiometric detection using a metallic copper electrode in reversed-phase and ion-exclusion chromatography with eluents containing ion-interaction reagents ». Journal of Chromatography A 699, n^o 1-2 (mai 1995) : 31–37. http://dx.doi.org/10.1016/0021-9673(95)00046-p.

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