The electrochemical investigation of inclusion complexes of nifedipine and amlodipine with ß-cyclodextrin and (2-hydroxypropyl)-ß-cyclodextrin

The electrochemical behavior of inclusion complexes of nifedipine (Nif) and amlodipine (Aml), a long-acting calcium channel blockers dihydropyridine (DHP) class, with ß-cyclodextrin (ßCD) and (2-hydroxypropyl)-ß-cyclodextrin (HPßCD), is examined using cyclic and square wave voltammetry in 0.05 M NaHCO3 and phosphate buffer (pH=11) on a gold electrode. The voltammograms show a single irreversible anodic wave with the current controlled by adsorption. It was found that phosphate buffer favorites the electrochemical activity of both complexes of Nif with the linear dependency of the oxidative currents on their concentrations. In phosphate buffer, only HPßCD-Aml complex showed linear dependency of the oxidative currents on the concentration. In 0.05 M NaHCO3 as electrolyte only HPßCD-Nif exhibited apparent activity. The initial potential of the anodic reaction as well as the value of the potential for anodic currents maximum of all the examined complexes in both electrolytes were shifted to the positive direction compared to their standards. In addition, the value of anodic currents decreased

The electrochemical investigation of inclusion complexes of nifedipine and amlodipine with ß-cyclodextrin and (2-hydroxypropyl)-ß-cyclodextrin

The electrochemical behavior of inclusion complexes of nifedipine (Nif) and amlodipine (Aml), a long-acting calcium channel blockers dihydropyridine (DHP) class, with ß-cyclodextrin (ßCD) and (2-hydroxypropyl)-ß-cyclodextrin (HPßCD), is examined using cyclic and square wave voltammetry in 0.05 M NaHCO3 and phosphate buffer (pH=11) on a gold electrode. The voltammograms show a single irreversible anodic wave with the current controlled by adsorption. It was found that phosphate buffer favorites the electrochemical activity of both complexes of Nif with the linear dependency of the oxidative currents on their concentrations. In phosphate buffer, only HPßCD-Aml complex showed linear dependency of the oxidative currents on the concentration. In 0.05 M NaHCO3 as electrolyte only HPßCD-Nif exhibited apparent activity. The initial potential of the anodic reaction as well as the value of the potential for anodic currents maximum of all the examined complexes in both electrolytes were shifted to the positive direction compared to their standards. In addition, the value of anodic currents decreased

Determination of critical conditions for the formation of electrodeposited copper structures suitable for electrodes in electrochemical devices

Electrodeposition of copper from acid sulfate solutions at overpotentials on the plateau of the limiting diffusion current density and at higher overpotentials was examined. The average current efficiencies for hydrogen evolution reaction are determined by a measurement of the quantity of evolved hydrogen and the overall electrodeposition current as a function of electrodeposition time, while morphologies of copper deposits are examined by the use of the scanning electron microscopy (SEM) technique. It is found that the open and porous structures of copper deposits (denoted and as honeycomb - like copper structures), suitable for electrodes in electrochemical devices such as fuel cells and chemical sensors, were reached by electrodeposition processes from solutions with the lower concentrations of Cu (II) ions (0.15 M CuSO 4 and less in 0.50 M H2SO4) at overpotentials outside the plateau of the limiting diffusion current density at which the quantity of evolved hydrogen was enough to change hydrodynamic conditions in the near - electrode layer. The main characteristics of these copper structures were craters or holes formed primarily due to the attachment hydrogen bubbles with agglomerates of copper grains between them

The mutual relation of decisive characteristics of electrolytic copper powder and effect of deposition conditions on them

The papers dealing with the effects of electrodeposition conditions on the decisive characteristics of electrolytic copper powder and their mutual relations are reviewed, and a semiquantitative theory based on them is presented. Also, the method for the estimation of the surface energy of disperse deposit formation based on the estimation of a surface area of deposits at different overpotentials is proposed. Then, the values of the surface energy of disperse deposit formation estimated in this way are used for the correlation of the specific surface of a powder to the electrodeposition conditions. The good agreement between the values of the specific surface of a powder determined in this way and those found in the literature is obtained. The apparent density of a powder as one of the decisive characteristics of metal powders is also correlated to the specific surface, and hence, to the electrodeposition conditions. In this chapter, the size of representative powder particle having the same specific surface as a powder is defined and the shape of the particle size distribution curve is analyzed. The problems concerning the effect of the particle shape and structure on the flowability of electrolytically formed copper powder are also discussed.© 2009 by Nova Science Publishers, Inc. All rights reserved

Aetiology of shame and its association with adolescent depression and anxiety: results from a prospective twin and sibling study

Background Shame is considered a maladaptive self-conscious emotion that commonly co-occurs alongside depression and anxiety. Little is known, however, about the aetiology of shame and its associations with depression and anxiety. We estimated, for the first time, genetic and environmental influences on shame and on its associations with depression and anxiety in adolescence. Methods The sample was twin and sibling pairs from the Genesis 1219 Study (Time 1, N = 2,685; males 42.8%, Mage = 14.95, SD = 1.67, age range: 12–21; Time 2, N = 1618; males 39.7%, Mage = 16.97, SD = 1.64, age range: 14–23). Participants completed validated questionnaires to measure shame (at Time 1), depression and anxiety (at Times 1 and 2). Results Shame was moderately to strongly associated with concurrent depression and anxiety. Prospectively, shame was significantly associated with an increase in depression, but not anxiety. Genetic analyses revealed that shame was moderately heritable with substantial nonshared environmental influence. The associations between shame and concurrent depression and anxiety were primarily accounted for by overlapping genetic influences. Prospectively, the association between shame and later depression was primarily accounted for by genetic and nonshared environmental influences shared with earlier depression. The unique association between shame and later depression was mostly explained by common nonshared environmental influences. Conclusions The findings offer novel evidence regarding aetiology of shame—although moderately heritable, shame in adolescents may also result from nonshared environmental factors. Genetic and nonshared environmental influences contribute to the co-occurrence of shame with depression and anxiety

Aetiology of shame and its association with adolescent depression and anxiety: results from a prospective twin and sibling study

Background Shame is considered a maladaptive self-conscious emotion that commonly co-occurs alongside depression and anxiety. Little is known, however, about the aetiology of shame and its associations with depression and anxiety. We estimated, for the first time, genetic and environmental influences on shame and on its associations with depression and anxiety in adolescence. Methods The sample was twin and sibling pairs from the Genesis 1219 Study (Time 1, N = 2,685; males 42.8%, Mage = 14.95, SD = 1.67, age range: 12–21; Time 2, N = 1618; males 39.7%, Mage = 16.97, SD = 1.64, age range: 14–23). Participants completed validated questionnaires to measure shame (at Time 1), depression and anxiety (at Times 1 and 2). Results Shame was moderately to strongly associated with concurrent depression and anxiety. Prospectively, shame was significantly associated with an increase in depression, but not anxiety. Genetic analyses revealed that shame was moderately heritable with substantial nonshared environmental influence. The associations between shame and concurrent depression and anxiety were primarily accounted for by overlapping genetic influences. Prospectively, the association between shame and later depression was primarily accounted for by genetic and nonshared environmental influences shared with earlier depression. The unique association between shame and later depression was mostly explained by common nonshared environmental influences. Conclusions The findings offer novel evidence regarding aetiology of shame—although moderately heritable, shame in adolescents may also result from nonshared environmental factors. Genetic and nonshared environmental influences contribute to the co-occurrence of shame with depression and anxiety

The mutual relation of decisive characteristics of electrolytic copper powder and effect of deposition conditions on them

The papers dealing with the effects of electrodeposition conditions on the decisive characteristics of electrolytic copper powder and their mutual relations are reviewed, and a semiquantitative theory based on them is presented. Also, the method for the estimation of the surface energy of disperse deposit formation based on the estimation of a surface area of deposits at different overpotentials is proposed. Then, the values of the surface energy of disperse deposit formation estimated in this way are used for the correlation of the specific surface of a powder to the electrodeposition conditions. The good agreement between the values of the specific surface of a powder determined in this way and those found in the literature is obtained. The apparent density of a powder as one of the decisive characteristics of metal powders is also correlated to the specific surface, and hence, to the electrodeposition conditions. In this chapter, the size of representative powder particle having the same specific surface as a powder is defined and the shape of the particle size distribution curve is analyzed. The problems concerning the effect of the particle shape and structure on the flowability of electrolytically formed copper powder are also discussed.© 2009 by Nova Science Publishers, Inc. All rights reserved

The mutual relation of decisive characteristics of electrolytic copper powder and effect of deposition conditions on them

The papers dealing with the effects of electrodeposition conditions on the decisive characteristics of electrolytic copper powder and their mutual relations are reviewed, and a semiquantitative theory based on them is presented. Also, the method for the estimation of the surface energy of disperse deposit formation based on the estimation of a surface area of deposits at different overpotentials is proposed. Then, the values of the surface energy of disperse deposit formation estimated in this way are used for the correlation of the specific surface of a powder to the electrodeposition conditions. The good agreement between the values of the specific surface of a powder determined in this way and those found in the literature is obtained. The apparent density of a powder as one of the decisive characteristics of metal powders is also correlated to the specific surface, and hence, to the electrodeposition conditions. In this chapter, the size of representative powder particle having the same specific surface as a powder is defined and the shape of the particle size distribution curve is analyzed. The problems concerning the effect of the particle shape and structure on the flowability of electrolytically formed copper powder are also discussed.© 2009 by Nova Science Publishers, Inc. All rights reserved