Application of MnOx – based electrodes into the industriel production of electric boilers

We have developed composite MnOx coated electrodes on metal oxidized substrate. Simple carbon steel was used as the substrate. The MnOx film was deposited electrochemically from an electrolyte containing monobasic carboxylic acids. Mixed electroneutral complexes [Mn(L)2(H2O)4] formation ensured the deposition of MnOx-based composite at low potentials. The corrosion resistance of the obtained composite films was very high. The industrial tests of the developed Fe, FeOy/MnOx electrodes showed their ability to work for at least 10000 hours. The developed electrodes were introduced into the industrial production of electric boilers "Energy" with direct heat carrier heating of various capacities, which are used in residential premises and other facilities. Their long-term operation confirmed their high performance characteristics

The mechanism of electrooxidation of Mn2+ ions

In this work the mechanisms of electrooxidation of Mn2+ to MnO2 were investigated in perchlorate, sulphate and acetate solutions. Density functional theory (DFT), as a quantum modeling method, was used for identification of red-ox potentials of one-electron oxidation of the aquacomplexes [Mn2+(H2O)6], [Mn2+(H2O)5(SO4 2-)]. The calculated values were significantly higher than the measured potentials of the initial stages of complexes oxidation on Pt electrode. The thermodynamical possibilities of formation of oxocomplexes and the kinetic measurements were analyzed. Based on this data it has been found that in perchlorate and sulphate solutions (pH 4) Mn2+-iones were oxidized due to the interaction with adsorbed •OH-radicals, produced by the water-splitting reaction. For strongly acid sulphate solutions (pH 1) it was observed the convergence of values of the potential of water-splitting reaction (1,2 V) and the potential of oxidation of [Mn2+(H2O)5(НSO4 -)] complex (1,13V). This points to simultaneous implementation of two reaction paths: the direct electrooxidation of Mn2+-iones and the oxidation due to the interaction with •OH-radicals. The calculated value of potential of electrooxidation of monoacetate aquacomplex of Mn2+-iones is notably low (0,66 V). This poin to the only electrooxidation path of the reaction. The calculated data have been confirmed by the kinetic measurements. The particles [Mn3+(H2O)5(Ас-)] rapidly disproportionate to MnO2 and [Mn2+(H2O)5(Ас-)] due to the features of carboxyl group. Квантово-хімічний аналіз реакцій окиснення гексааквакомплексов Mn2+ і їх деяких монозаміщених форм показав, що стандартні окислювально-відновні потенціали одноелектронного окиснення [Mn2+(H2O)6], [Mn2+(H2O)5(SO4 2–)] істотно перевищують зареєстровані потенціали початку анодного окиснення цих комплексів на платиновому електроді. Тому в перхлоратних і сульфатних розчинах при рН 4 окиснення Mn2+ здійснюється хімічно продуктами електроокиснення води, переважно •ОН-радикалами, що підтверджено кинетичними вимірами. У кислих сульфатних розчинах (рН 1) з огляду на зближення потенціалів електроокиснення води (1,2 В) і комплексу [Mn2+(H2O)5(НSO4 –)] (1,13 В) анодная реакція включає два маршрути: пряме електроокиснення Mn2+ -іонів і їх окиснення •ОН-радикалами. На відміну від цього, моноацетатні аквакомплекси Mn2+, маючи аномально низький окислювально-відновний потенціал (φ0 = 0,66 В), окислюються тільки електрохімічним шляхом при φ = 0,8 ÷ 1,0 В, (до початку розкладання води). Утворені частки [Mn4+(H2O)5(Ас–)] швидко диспропорционують до MnO2 завдяки мостикову зв'язуванню біядерного комплексу ацетат-іоном. Квантово-химический анализ реакций окисления гексааквакомплексов Mn2+ и их некоторых монозамещенных форм показал, что стандартные окислительно-восстановительные потенциалы одноэлектронного окисления [Mn2+(H2O)6], [Mn2+(H2O)5(SO4 2–)] существенно превышают регистрируемые потенциалы начала анодного окисления этих комплексов на платиновом электроде. Поэтому в перхлоратных и сульфатных растворах при рН 4 окисление Mn2+ осуществляется химически продуктами электроокисления воды, преимущественно •ОНрадикалами, что подтверждено кинетическими измерениями. В кислых сульфатных растворах (рН 1) ввиду сближения потенциалов электроокисления воды (1,2 В) и комплекса [Mn2+(H2O)5(НSO4 –)] (1,13 В) анодная реакция включает два маршрута: прямое электроокисление Mn2+-ионов и их окисление •ОН-радикалами. В отличие от этого, моноацетатные аквакомплексы Mn2+, обладая аномально низким окислительновосстановительным потенциалом (φ0 = 0,66 В), окисляются только электрохимически при φ = 0,8÷1,0 В, (до начала разложения воды). Образующиеся частицы [Mn4+(H2O)5(Ас–)] быстро диспропорционируют до MnO2 благодаря мостиковому связыванию биядерного комплекса ацетат-ионом

Cxcr4-ccr7 heterodimerization is a driver of breast cancer progression

Metastatic breast cancer has one of the highest mortality rates among women in western society. Chemokine receptors CXCR4 and CCR7 have been shown to be linked to the metastatic spread of breast cancer, however, their precise function and underlying molecular pathways leading to the acquisition of the pro-metastatic properties remain poorly understood. We demonstrate here that the CXCR4 and CCR7 receptor ligands, CXCL12 and CCL19, cooperatively bind and selectively elicit synergistic signalling responses in invasive breast cancer cell lines as well as primary mammary human tumour cells. Furthermore, for the first time, we have documented the presence of CXCR4-CCR7 heterodimers in advanced primary mammary mouse and human tumours where number of CXCR4-CCR7 complexes directly correlate with the severity of the disease. The functional significance of the CXCR4-CCR7 association was also demonstrated when their forced heterodimerization led to the acquisition of invasive phenotype in non-metastatic breast cancer cells. Taken together, our data establish the CXCR4-CCR7 receptor complex as a new functional unit, which is responsible for the acquisition of breast cancer cell metastatic phenotype and which may serve as a novel biomarker for invasive mammary tumours.Valentina Poltavets, Jessica W. Faulkner, Deepak Dhatrak, Robert J. Whitfield, Shaun R. McColl and Marina Kochetkov

The chemokine receptor CCR7 promotes mammary tumorigenesis through amplification of stem-like cells

The chemokine receptor CCR7 is widely implicated in breast cancer pathobiology. Although recent reports correlated high CCR7 levels with more advanced tumor grade and poor prognosis, limited in vivo data are available regarding its specific function in mammary gland neoplasia and the underlying mechanisms involved. To address these questions we generated a bigenic mouse model of breast cancer combined with CCR7 deletion, which revealed that CCR7 ablation results in a considerable delay in tumor onset as well as significantly reduced tumor burden. Importantly, CCR7 was found to exert its function by regulating mammary cancer stem-like cells in both murine and human tumors. In vivo experiments showed that loss of CCR7 activity either through deletion or pharmacological antagonism significantly decreased functional pools of stem-like cells in mouse primary mammary tumors, providing a mechanistic explanation for the tumor-promoting role of this chemokine receptor. These data characterize the oncogenic properties of CCR7 in mammary epithelial neoplasia and point to a new route for therapeutic intervention to target evasive cancer stem cells.ST Boyle, WV Ingman, V Poltavets, JW Faulkner, RJ Whitfield, SR McColl, and M Kochetkov

The principal properties of molibdenum-phosphate heteropolianions and their application as catalysts

Polyoxometallates (POMs) are increasingly used as electrocatalysts for the determination of several types of species. Dawson and Keggin-type heteropoly anions are preferentially used in industry as catalysts. Properties of Dawson-type molybdophosphate heteropoly anions are discussed in the present review. Electrochemical behavior of Keggin- and Dawsontype molybdophosphate heteropoly anions has been reviewed. The oxidation-reduction potentials of electron reductions of the [P2Mo18O62] 6– anion in solutions with various pH and in different media are cited. Special focus is made on methods of designing of electrodes modified by POMs. The most common deposition techniques of POMs include chemisorption, electrodeposition, encapsulation in polymers or sol–gels, and formation of hybrid POM–organic species. Advantages and disadvantages of various techniques are discussed. Modified electrodes are characterized by electrochemical stability, shifting of characteristic peaks and sensitivity to pH change. Проаналізовано результати досліджень електрохімічних властивостей і стабільності молібдофосфорних гетерополікомплексiв структури Кеггіна і Доусона. Визначено характерні потенціали електронних переходів 18-МФА та їх залежність від рН у водних розчинах. Розглянуто основні методи формування електродів, модифікованих ГПК, та порівнюються їх каталітичні властивості iз вихідними речовинами. Проанализированы результаты исследований электрохимических свойств и стабильности молибдофосфорных гетерополикомплексов структуры Кеггина и Доусона. Определены характерные потенциалы электронных переходов 18-МФА и их зависимость от рН в водных растворах. Рассмотрены основные методы формирования электродов, модифицированных ГПК, и сравниваются их каталитические свойства с исходными вещеставами