Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Peroxynitrite oxidation of sulfhydryls. The cytotoxic potential of superoxide and nitric oxide.

Peroxynitrite-mediated tyrosine nitration catalyzed by superoxide dismutase

Hexagonal sodium yttrium fluoride, NaYF4, is the most efficient host material to date for green (Yb3+/Er3+ doped) and blue (Yb3+/Tm3+ doped) upconversion (UC) phosphors, i.e., phosphors which emit visible light upon infrared (IR) excitation. The structure of the hexagonal phase gives rise to controversy about the cation sites and distribution. The X-ray diffraction patterns of our phosphors do not fit well with the crystal structure reported for NaNdF4 (space group P6, Z = 1.5). The Na:M ratio (M = Y, Nd, Er, Tm, Yb) of the hexagonal phase deviates significantly from 1:1, and it depends on M and the preparation temperature. It is proposed that the hexagonal phase is isostructural to the chlorides Na3xM2-xCl6 with M = La−Sm. This structure (space group P63/m, Z = 1) contains only one M3+ site which is partially occupied by Na+, and the formula Na3xM2-xF6 (x ≈ 0.45) accounts for the nonstoichiometry. The model was derived from powder X-ray diffraction on the green and blue phosphor materials as well as the...

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Hexagonal Sodium Yttrium Fluoride Based Green and Blue Emitting Upconversion Phosphors

Publisher Summary Nitric oxide (.NO) is an important and largely unrecognized mediator of oxygen radical injury because it contains an unpaired electron that readily combines with many free radicals. Endothelium and neurons produce nitric oxide as an intercellular messenger, which has important roles in vasoregulation and synaptic plasticity. Nitric oxide reacts rapidly with superoxide to form the strong oxidant, peroxynitrite anion (ONOO - ). Activated macrophages and neutrophils can produce nitric oxide and superoxide at similar rates. This chapter presents that essentially all of the nitric oxide produced by rat alveolar macrophages activated with phorbol ester is converted to peroxynitrite. Peroxynitrite is not a free radical because the unpaired electrons on nitric oxide and superoxide have combined to form a new N–O bond in peroxynitrite. Peroxynitrite anion can be stored for weeks in alkaline solution or even entrapped in solid forms. During its decomposition at physiological pH, peroxynitrite can produce some of the strongest oxidants known in a biological system, initiating reactions characteristic of hydroxyl radical, nitronium ion, and nitrogen dioxide. The unusual stability of peroxynitrite as an anion contributes to its toxicity by allowing it to diffuse far from its site of formation while being selectively reactive with cellular targets.

Oxidative chemistry of peroxynitrite.

Manganese-based octahedral molecular sieves of the type K-OMS-2 (cryptomelane structure) with different morphologies and specific surface areas in the range of 20–135 m2 g−1 were prepared via synproportionation of KMnO4 and Mn2+ salts, either in acidic aqueous suspension (reflux method) or by a solid-state reaction, and via oxidation of MnSO4 either by K2Cr2O7 or by molecular oxygen in aqueous solution. For the reflux method, the influence of K+ cations for the formation of the OMS-2 structure was proven. When KMnO4 is replaced by Ba(MnO4)2, the anion in the Mn2+ salt exerts a strong influence on the synthesis product. All materials were characterized by elemental analysis (ICP-OES), XRD, nitrogen sorption, scanning electron microscopy and TGA. For the oxidation of benzyl alcohol with molecular oxygen in liquid toluene at 110 °C, the catalytic activity of the K-OMS-2 materials is directly correlated to their specific surface area ABET. Since ABET increases with decreasing average crystallite diameter, the catalytic conversion presumably occurs at the outer crystallite surface. These relations are independent of morphology or synthesis procedure. The K-OMS-2 materials are more active than crystalline manganese oxides (MnO, Mn2O3, Mn3O4, β-MnO2), but less active than amorphous MnO2. Regeneration of deactivated K-OMS-2 catalysts can be achieved by calcining at 300 °C in air, partly due to the reversible desorption of water.

Octahedral molecular sieves of the type K-OMS-2 with different particle sizes and morphologies: Impact on the catalytic properties in the aerobic partial oxidation of benzyl alcohol

Optical spectroscopic and structural properties of V3+ -doped fluoride, chloride, and bromide elpasolite lattices

Three-Spin System with a Twist: A Bis(semiquinonato)copper Complex with a Nonplanar Configuration at the Copper(II) Center†

Etude des reactions des halogenures de NH 4 avec: les sesquioxydes de terres rares, les metaux, les sulfures, seleniures, phosphures, carbures. Elles peuvent etre divisees en 2 groupes: les reactions redox et les reactions acide-base

Versatility and low-temperature synthetic potential of ammonium halides

The action of alkali metals ( A  Li - Cs ) on rare earth trihalides MX 3 results in the formation of binary and ternary reduced halides and, additionally and frequently, alkali halides AX. When oxygen is present, as a contamination of the reaction container, as oxyhalide MOX or as sesquioxide M 2 O 3 , crystallization of oxyhalides ( e.g . Sm 4 OCl 6 , NdOCl) or even of the sesquioxides themselves is observed upon cooling of these strongly reducing melts. The crystal structures of Sm 2 O 3 (B type, C 2/ m , a = 1419.75(9), b = 362.73(3), c = 885.61(5) pm, β = 99.986(5) °, R = 0.037, R w = 0.028), Yb 2 O 3 and Sc 2 O 3 (both C type, Ia 3, a = 1043.42(4) and 984.46(4) pm, R = 0.065, R w = 0.058 and R = 0.055, R w = 0.045 respectively) have been refined from single-crystal diffractometer data.

Thomas Schleid

Papers

Octahedral molecular sieves of the type K-OMS-2 with different particle sizes and morphologies: Impact on the catalytic properties in the aerobic partial oxidation of benzyl alcohol

Optical spectroscopic and structural properties of V3+ -doped fluoride, chloride, and bromide elpasolite lattices

Three-Spin System with a Twist: A Bis(semiquinonato)copper Complex with a Nonplanar Configuration at the Copper(II) Center†

Versatility and low-temperature synthetic potential of ammonium halides

Single crystals of rare earth oxides from reducing halide melts