Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: Cu2+; ATPase; CPx; CopB. Includes bibliographical references (p. 36-42).

No description available.

Thesis (M.S.)--University of Toledo, 2009. / Typescript. " As partial fulfillment of the requirements for the Master of Science in Physics." "A thesis entitled"--at head of title. Bibliography: leaves 21-22.

Copper ions are widely reported to have pro-angiogenic properties and can be incorporated into bone substitute bioceramics as bio-instructive cues to stimulate infiltration of blood vessels into the material after implantation. By this, the viability of bone forming cells within the scaffold (which decreases rapidly with increasing depth from the surface) could be enhanced, and the healing process (resorption and replacement of the scaffold with new, natural bone) hastened. Pure-phase copper-doped hydroxyapatite (CuHA) materials with x = 0 - 1 in the nominal formula Ca10(PO4)6CuxOy(H)z were prepared by solid state synthesis at 1100 °C. Attempted preparation of compositions with y = 0.1 and 0.5 in the nominal formula Ca10−yCuy(PO4)6(OH)2 by an aqueous precipitation method led to formation of biphasic products containing considerable amounts of β-tricalcium phosphate. Dissolution tests in TRIS buffer, cell culture medium and citric acid buffer indicated that copper ions are released from CuHA materials at concentrations that increase with copper content in the materials and soaking time, and are in a physiologically-relevant range. This offers the potential to tune copper ion release by controlling the copper content of CuHA materials. In vitro in cultures of human osteoblast-like cells and human mesenchymal stem cells (hMSCs), copper ions released from CuHA downregulated ALP expression in both cell types and (particularly for hMSCs) upregulated VEGF expression. In vivo, the prepared copper-containing materials had pro-angiogenic and possible inflammatory effects in the chick embryo yolk sac membrane and chorioallantoic membrane angiogenesis assays. Copper ions released from beads grafted into the developing chick limb affected the integrity of developing blood vessels in the graft vicinity, causing haemorrhaging. The results suggest that the coupling of angiogenesis and osteogenesis, perhaps through the hypoxia and NO pathways, are important for copper's biological effects, and with further investigation and careful control of dose and timing these effects may be better understood and controlled.

In this work we present the first characterization of a Cu2+-transporting ATPase. The thermophilic bacteria Archaeoglobus fulgidus contains two genes, CopA and CopB, encoding for CPx-ATPases. CopB belongs to the subgroup IB-4 of the CPX-ATPases. These enzymes are characterized by a CPH motif in the 6th transmembrane domain and a His-rich N-terminus metal binding domain (MBD). CopB was heterologously expressed in E. coli. Membranes were prepared and used to measure activity. CopB was active at high temperature (75º C), high ionic strength and pH 5.7. The enzyme was activated by Cu2+, and in to a lesser extent by Ag+ and Cu+. CopB showed a Vmax = 5 µmol/mg/h and a high apparent affinity (K1/2 = 0.28 ± 0.09 μM) for Cu2+. Uptake of 64Cu2+ into everted vesicles was also measured in order to show that Cu2+ is not only activating the enzyme but being transported. Compared with CopB-WT, CopB-T (lacking the N-terminus MBD) did not show any difference in its activation by the different metal ions, demonstrating that the cytoplasmic MBD has no role in the metal selectivity. CopB-T also showed a 40 % decrease in the ATPase activity. CopB-WT and CopB-T presented similar levels of phosphorylation. However, CopB-T exhibited a reduced rate of dephosphorylation (slower transition from the E2P to the E2 conformation). These observations suggest a regulatory role for the cytoplasmic MBD.

Thesis (M.S.) -- Worcester Polytechnic Institute. / Keywords: metal transport; Cu+; Cys; PIB-type ATPase; CopA. Includes bibliographical references (p. 39-45).

Thesis (Ph. D.), Memorial University of Newfoundland, 1998. / Bibliography: leaves 314-331.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1972. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

M. Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / This work investigates the possible use of chitosan beads and polyaniline grafted chitosan beads (PGCB) for the adsorption of copper ions from copper contaminated water. For this purpose chitosan flakes were converted to chitosan beads. However, a variable from a number of reaction variables (aniline concentration, chitosan concentration, temperature, acid concentration, reaction time and initiator concentration) was varied while others was kept constant, in an attempt to determine the best conditions for grafting of polyaniline onto chitosan beads. Percentage (%) grafting and % efficiency were key parameters used to determine such conditions. The chitosan beads and PGCB were characterized using physical techniques such as Fourier transformed infra red (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM). The beads were used as an adsorbent for copper ions removal. The effect of pH on the removal rate of copper (II) by PGCB was investigated on by varying the pH values from pH 3 to 8 at an initial concentration of 40 mg/l. The effect of contact time, initial concentration and temperature was also investigated. The Langmuir and Freundlich model were used to describe adsorption isotherms for chitosan beads and PGCB, with correlation coefficient (R2) as the determining factor of best fit model. The thermodynamics of adsorption of copper (II) onto PGCB was described by parameters such as standard Gibb’s free energy change (ΔGo), standard enthalpy change (ΔHo), and standard entropy change (ΔSo) while the pseudo first-order and pseudo second-order kinetic model was used to describe kinetic data for the PGCB, with R2 and chi- square test (  2) as the determinant factor of best fit model. From the desorption studies, the effect of eluants (HCl and HNO3) and contact time on percentage desorption of PGCB loaded copper (II) ion was investigated upon. In determining the reusability of the PGCB loaded copper (II) ion, three cycles of adsorption/desorption studies was carried out. The results obtained from determining the best conditions for grafting polyaniline onto chitosan beads revealed the following grafting conditions; [Aniline] 0.1 g/l, [temperature] 35oC, [chitosan] 0.45 g/l, [HCl] 0.4 g/l, [(NH4)2S2O8] 0.35 g/l, and [time] 1 h. These conditions were applied in the grafting of polyaniline onto chitosan beads. FTIR analysis showed increase intensity in the grafted beads which provided evidence of grafting, XRD measurement showed a decrease in crystallinity in the PGCB as against the partial crystalline nature of chitosan. In SEM analysis, evidence of grafting was revealed by the closed gap between the polysaccharide particles in the PGCB. From the investigation carried out on the effect of pH on the percentage removal of Cu(II) ions by PGCB, the optimal pH value was found to be pH 5 with a percentage removal of 100% and this value was used for all adsorption experiment. Also from the investigation performed on the effect of contact time and initial concentration, it was observed that there was a sharp increase in the amount of Cu(II) ions adsorbed by PGCB up until contact time of 30 min and thereafter, it increases gradually. From the experiment carried out on the effect of temperature on adsorption capacity, there was an increase in adsorption capacity with increase in temperature. Moreover, at temperatures of 25oC, 35 oC and 45oC the Langmuir model gave the best fit for the chitosan beads having R2 values that are equal and greater than 0.942 in contrast to Freundlich having R2 values that is equal and greater than 0.932. The maximum adsorption capacity (Qm) from Langmuir model at these temperatures were 30.3 mg/g, 47.6 mg/g and 52.6 mg/g respectively. Also, the Langmuir model gave the best fit for the PGCB having R2 values that are equal and greater than 0.956 in contrast to Freundlich model with R2 values that is equal and greater than 0.935. The Qm from Langmuir model at these temperatures were 80.3 mg/g, 90.9 mg/g and 100 mg/g respectively. The values of Qm for PGCB appears to be significantly higher when compared to that of chitosan beads and this makes PGCB a better adsorbent than chitosan beads. From the thermodynamic studies carried out on PGCB, the values of ΔGo were negative and this denotes that the adsorption of copper ions onto PGCB is favorable and spontaneous, the positive value of ΔHo shows the adsorption process is endothermic and the positive value of ΔSo illustrate increased randomness at the solid-liquid interface during the adsorption process. Also, from the kinetic studies carried out on the PGCB, the pseudo second-order kinetic model best described the kinetic data having R2 values that are equal and greater than 0.994 in contrast to the pseudo first-order kinetic model with R2 values that is equal and greater than 0.913. The  2 values for the pseudo first-order and pseudo second-order kinetic model were similar; however, there was a large difference for qe between the calculated (qeCal) values of the first-order kinetic model and experimental (qeExp) values. In the case of the pseudo second-order model, the calculated qe values agree very well with the experimental data. Desorption of the metal ions from PGCB was efficient. 0.5 M HCl was successfully used in desorbing the beads loaded with copper ions and a percentage desorption of 97.1% was achieved at contact time of 180 min. PGCB were successfully re-used for adsorption/desorption studies were a Qm of 83.3 mg/g, 83.3 mg/g and 76.9 mg/g was achieved in the first, second and third cycle respectively.

O efeito bactericida de íons cobre é bem conhecido; no entanto a atividade inibitória depende diretamente da concentração desses íons no material base. Contudo, essa concentração deve ser controlada, pois o excesso destes íons pode ser tóxico e além disso, a implantação de cobre pode comprometer a resistência a corrosão do substrato metálico. A propriedade bactericida é desejável para aplicação em ligas metálicas empregadas em diversos setores, na assepsia de materiais que tenham contato direto com subprodutos que necessitam alta pureza e com baixíssimos índices de contaminação. O aço inoxidável austenítico AISI 304 é amplamente utilizado devido às suas propriedades mecânicas e de resistência à corrosão. Considerando isso, o aço AISI 304 é o foco do presente estudo, mesclando as características anticorrosivas naturais com a assepsia oligodinâmica proveniente da dopagem com íons de cobre. Nesse sentido, avaliou a resistência à corrosão do aço inoxidável AISI 304 com diferentes doses de cobre implantado (1015 íons.cm-2 e 1016 íons.cm-2) por monitoramento do potencial de circuito aberto e voltametria cíclica em uma solução eletrolítica de NaCl 3,5 % em peso. Através de simulações computacionais, previu-se que nos parâmetros escolhidos, a profundidade de implantação dos íons no substrato atingiu até 40 nm da superfície, com uma concentração de pico, maior teor de cobre, na profundidade de 12 nm. As amostras com doses de 1015 íons.cm-2 de cobre apresentaram o potencial de pites semelhante ao aço inoxidável austenítico AISI 304 sem implantação de Cu. Na análise de EDS observou-se que as áreas que não sofreram corrosão, apresentaram melhor distribuição dos elementos de liga e do cobre implantado em comparação com as regiões com maior incidência de pites. A maior intensidade de pites foi encontrada para a amostra com maior dose de cobre implantado (1016 íons.cm-2 de cobre). / The bactericidal effect of copper ions is well known; however, the inhibitory activity depends directly on the concentration of these ions in the base material. However, this concentration should be controlled because the excess of these ions can be toxic and the implantation of copper may compromise the corrosion resistance of the metal substrate. The bactericidal property is desirable for application in metal alloys used in the several sectors, in the asepsis of materials that have direct contact with by-products that require high purity and with very low contamination rates. The AISI 304 austenitic stainless steel is widely used because of its mechanical properties and corrosion resistance. Considering this, the AISI 304 is the focus of the present study, mixing the natural anticorrosive characteristics with the oligodynamic aseptic from the copper ions doping. The corrosion resistance of AISI 304 stainless steel with different doses of implanted copper (1015 ions.cm-2 and 1016 ions.cm-2) was evaluated by monitoring the open circuit potential and cyclic voltammetry in an electrolytic solution of NaCl 3,5% by weight. Through computational simulations, it was predicted that in the chosen parameters, the implantation depth of the ions in the substrate reached up to 40 nm from the surface, with a peak concentration, higher copper content, at the depth of 12 nm. The samples with doses of 1015 ions.cm-2 of copper had the pit potential similar to the austenitic stainless steel AISI 304 without implantation of Cu. In EDS analysis, it was observed that the areas that did not undergo corrosion had better distribution of the alloying elements and of the implanted copper compared to the regions with a higher incidence of pitting. The highest pitting intensity was found for the sample with the highest dose of implanted copper (1016 ions.cm-2 copper).