Pencil it in: pencil drawn electrochemical sensing platforms

Inspired by recent reports concerning the utilisation of hand drawn pencil macroelectrodes (PDEs), we report the fabrication, characterisation (physicochemical and electrochemical) and implementation (electrochemical sensing) of various PDEs drawn upon a flexible polyester substrate. Electrochemical characterisation reveals that there are no quantifiable electrochemical responses upon utilising these PDEs with an electroactive analyte that requires an electrochemical oxidation step first, therefore the PDEs have been examined towards the electroactive redox probes hexaammineruthenium(III) chloride, potassium ferricyanide and ammonium iron(II) sulfate. For the first time, characterisation of the number of drawn pencil layers and the grade of pencil are examined; these parameters are commonly overlooked when utilising PDEs. It is demonstrated that a PDE drawn ten times with a 6B pencil presented the most advantageous electrochemical platform, in terms of electrochemical reversibility and peak height/analytical signal. In consideration of the aforementioned limitation, analytes requiring an electrochemical reduction as the first process were solely analysed. We demonstrate the beneficial electroanalytical capabilities of these PDEs towards p-benzoquinone and the simultaneous detection of heavy metals, namely lead(II) and cadmium(II), all of which are explored for the first time utilising PDEs. Initially, the detection limits of this system were higher than desired for electroanalytical platforms, however upon implementation of the PDEs in a back-to-back configuration (in which two PDEs are placed back-to-back sharing a single connection to the potentiostat), the detection limits for lead(II) and cadmium(II) correspond to 10 μg L−1 and 98 μg L−1 respectively within model aqueous (0.1 M HCl) solutions.

Dokumente zur geschichte des europäischen krieges, 1914/15 mit besonderer berücksichtigung von Österrreich-Ungarn und Deutschland, gesammelt und chronologisch

Issued in parts.

Recueil des planches du Dictionnaire de chimie et de métallurgie : faisant partie del'Encyclopédie Méthodique par ordre de matières ...

"Premier partie. Chimie" ; "Seconde partie. Métallurgie "

Der fall des hauses Stuart und die succession des hauses Hannover in Gross-Britannien und Irland, im zusammenhange der europäischen angelegenheiten von 1660-1714.

1. bd. Die zeit Carls II. von England von 1660-1674.--2. bd. Die zeit Carls II. von England von 1675-1685.--3. bd. Die zeit Jacobs II. von England vom februar 1685 bis zum märz 1688.--4. bd. Die katastrophe Jacobs II., die neue thronfolge und die allianz von 1689.--5. bd. Der grosse krieg von 1689 an bis zum aufbruche Wilhelms III. nach Irland, die kriegesjahre 1690 und 1691.--6. bd. Die kriegesjahre 1692, 1693 und 1694.--7. bd. Die kriegesjahre 1695, 1696, 1697, und der friede von Ryswyck.--8. bd. Die zeit der beiden theilungsverträge über die spanische monarchie bis zum tode Carls II., november 1700.--9. bd. Die zeit der vorbereitung und des abschlusses der grossen allianz von 7. september 1701 und die europäische lage der dinge bis zum tode Wilhelms III., 8./19. märz 1702.--10. bd. Die kriegsjahre 1702 und 1703.--11. bd. Die kriegsjahre 1704 und 1705.--12. bd. Die kriegsjahre 1706 und 1707.--13. bd. Die kriegsjahre 1708, 1709 und 1710.--14. bd. Die jahre 1711 bis 1714.

Actensammlung aus der Zeit der Helvetischen Republik (1798-1803)

Added t.-p.: Amtliche Sammlung der Acten aus der Zeit der Helvetischen Republik (1798-1803) im Anschluss an die Sammlung der ältern eidg. Abschiede. Hrsg. auf Anordnung der Bundesbehörden...

Die streifkorps im deutschen befreiungskriege 1813 nach kriegsarchivarischen quellen,

atb.I. Bis zum waffenstillstande.--abt.II. Die ereignisse vom waffenstillstande bis zum rückzug Napoleons hinter den Rhein.

Der Fall des Hauses Stuart und die Succession des Hauses Hannover in Gross-Britannien und Irland, im zusammenhangen der europäischen angelegenheiten von 1660-1714.

1. bd. Die Zeit Carls II. von England von 1660-1674.--2. bd. Die Zeit Carls II. von England von 1675-1685.--3 bd. Die Zeit Jacobs II. von England vom februar 1685 bis zum märz 1688.--4. bd. Die katastrophe Jacobs II., die neue thronfolge und die grosse allianz von 1689.--5. bd. Der grosse krieg von 1689 an bis zum aufbruche Wilhelms III. nach Irland, die kriegesjahre 1690 und 1691.--6. bd. Die kriegesjahre 1692, 1693 und 1694.--7. bd. Die kriegesjahre 1695, 1696, 1697, und der friede von Ryswyck.--8. bd. Die Zeit der beiden theilungsverträge über die spanische monarchie bis zum tode Carls II., november 1700.--9. bd. Die Zeit der vorbereitung und des abschlusse der grossen allianz vom 7. september 1701 und die europäische lage der dinge bis zum tode Wilhelms III., 8/19. märz 1702.--10. bd. Die kriegsjahre 1702 und 1703.--11. bd. Die kriegsjahre 1704 und 1705.--12. bd. Die kriegsjahre 1706 und 1707.--13. bd. Die kriegsjahre 1708, 1709 und 1710.--14. bd. Die jahre 1711 bis 1714.

Novel monoclonal antibody recognition of oxidative DNA damage adduct, deoxycytidine-glyoxal

Glyoxal, a reactive aldehyde, is a decomposition product of lipid hydroperoxides, oxidative deoxyribose breakdown, or autoxidation of sugars, such as glucose. It readily forms DNA adducts, generating potential carcinogens such as glyoxalated deoxycytidine (gdC). A major drawback in assessing gdC formation in cellular DNA has been methodologic sensitivity. We have developed an mAb that specifically recognizes gdC. Balb/c mice were immunized with DNA, oxidatively modified by UVC/hydrogen peroxide in the presence of endogenous metal ions. Although UVC is not normally considered an oxidizing agent, a UVC/hydrogen peroxide combination may lead to glyoxalated bases arising from hydroxyl radical damage to deoxyribose. This damaging system was used to induce numerous oxidative lesions including glyoxal DNA modifications, from which resulted a number of clones. Clone F3/9/H2/G5 showed increased reactivity toward glyoxal-modified DNA greater than that of the immunizing antigen. ELISA unequivocally showed Ab recognition toward gdC, which was confirmed by gas chromatography-mass spectrometry of the derivatized adduct after formic acid hydrolysis to the modified base. Binding of Ab F3/9 with glyoxalated and untreated oligomers containing deoxycytidine, deoxyguanosine, thymidine, and deoxyadenosine assessed by ELISA produced significant recognition (p 0.0001) of glyoxal-modified deoxycytidine greater than that of untreated oligomer. Additionally, inhibition ELISA studies using the glyoxalated and native deoxycytidine oligomer showed increased recognition for gdC with more than a 5-fold difference in IC50 values. DNA modified with increasing levels of iron (II)/EDTA produced a dose-dependent increase in Ab F3/9 binding. This was reduced in the presence of catalase or aminoguanidine. We have validated the potential of gdC as a marker of oxidative DNA damage and showed negligible cross-reactivity with 8-oxo-2'-deoxyguanosine or malondialdehyde-modified DNA as well as its utility in immunocytochemistry. Formation of the gdC adduct may involve intermediate structures; however, our results strongly suggest Ab F3/9 has major specificity for the predominant product, 5-hydroxyacetyl-dC.

The chemistry of ceramic glazes

The development of ideas and theories concerning the structure of glazes, as one of the glassy materials, are reviewed in the general introduction. The raw materials and the manufacturing process for glazes are described (Chapter One). A number of new vanadyl(IV) dipyridylamine and tripyrldylamine complexes have been prepared, various spectroscopic techniques are used in the investigation of the vanadyl ion in a weak ligand field, the situation of those found in a glaze environment (Chapter Three). In glaze recipes containing silica, potash feldspar, china clay, MO(M= Ca, Sr, Sa, Ti and Zn) and NiO, the ligand field theory is used in the elucidation of the effect of M (in MO) on the absorption spectra and coordination behaviour of Ni(II) in glazes. The magnetic and visible spectral results are reviewed in terms of Dietzel's idea of field strength of M and also in terms of Shteinberg's theory of glaze structure. X-ray diffraction is used for the identification of various species that formed after the firing process of glazes (Chapter Four). In Chapter Five, [] Mossbauer spectroscopy, supplemented by E.S.R., X-ray and visible spectral measurements are used in the investigation of iron in a glaze composition similar to that used in Chapter Four. The Mossbauer results are used in following the influence of; M in MO (M= Sr, Ca and Ba), oxides of titanium(IV) and vanadium(V ), and firing conditions on the chemistry of iron. Generally the iron(II) and iron(III) in the fired glazes are in octahedral sites although there are a range of similar, though not identical environments. A quite noticable influence of M (in MO) on the resonance line width is seen. In one case evidence is found for iron(IV) in an iron/vanadium glaze. E.S.R. of vanadium containing glazes indicate that vanadium is present as V02+ in a highly distorted tetragonal environment .

Sulphide ore minerals:surface chemical properties

The surfaces of iron-containing sulphide minerals were oxidised by a range of inorganic oxidants, and the resultant surface alteration products studied using various spectroscopic techniques. The characterisation of surface oxidation is relevant to the alteration of ores in nature and their behaviour during flotation and leaching, of importance to the metallurgical industry. The sulphides investigated included pyrite (FeS2), hexagonal pyrrhotine (Fe9S10), monoclinic pyrrhotine (Fe7Se), violarite (FeNi2S4), pentlandite ((FeiNi)9Se), chalcopyrite (CuFeS2) and arsenopyrite (FeAsS). The surfaces were oxidised by various methods including acid (sulphuric), alkali (ammonium hydroxide), hydrogen peroxide, steam, electrochemical and air/oxygen (in a low-temperature (150ºC) furnace), The surfaces were examined using surface sensitive chemical spectroscopic methods including x-ray photoelectron spectroscopy (ms), Auger electron spectroscopy (LES) and conversion electron Mössbauer spectroscopy (CEKS). Physical characterisation of the surfaces was undertaken using scanning electron microscopy (SM), spectral reflectance measurements and optical microscopy. Bulk characterisation of the sulphide minerals was undertaken using x-ray diffraction and electron microprobe techniques. Observed phases suggested to form in most of the sulphide surfaces include Fe204, Fe1-x0, Fe202, Fe00H, Fe(OH)3, with iron II & III oxy-sulphates. The iron sulphides show variable extents of oxidation, indicating pyrite to be the most stable. Violarite shows stability to oxidation, suggested to result from both its stable spinel crystal structure, and from the rapid formation of sulphur at the surface protecting the sub-surface from further oxidation. The phenomenon of sub-surface enrichment (in metals), forming secondary sulphides, is exhibited by pentlandite and chalcopyrite, forming violarite and copper sulphides respectively. The consequences of this enrichment with regard to processing and leaching are discussed. Arsenopyrite, often a hindrance in ore processing, exhibits the formation of arsenic compounds at the surface, the dissolution of which is discussed in view of the possible environmental hazard caused by the local pollution of water systems. The results obtained allow a characterisation of the sulphides in terms of their relative stability to oxidation, and an order of stability of the sulphide surfaces is proposed. Models were constructed to explain the chemical compositions of the surfaces, and the inter-relationships between the phases determined at the surface and in the sub-surface. These were compared to the thermo-chemically predicted phases shown in Eh/pH and partial pressure diagrams! The results are discussed, both in terms of the mineralogy and geochemistry of natural ores, and the implications for extraction and processing of these ore minerals.