ALBERT

Description: Stylolites and the interfaces to the host limestone have been investigated by means of a multidisciplinary analytical approach (thin section microscopy, FIB-TEM, organic geochemistry and petrography). Carbonate dissolution assuming different boundary conditions was simulated applying a generic hydrogeochemical modelling approach. It is the conceptual approach to characterize and quantify traceable organic-inorganic interactions in stylolites dependent on organic matter type and its thermal maturity, and to follow stylolite formation in carbonates as result of organic matter reactivity rather than pressure solution as a main control. The investigated stylolite samples are of Upper Permian (Lopingian, Zechstein), Middle Triassic (Muschelkalk), and Late Cretaceous (Maastrichtian) age, and always contain marine organic matter. The thermal maturity of the organic matter ranges from the pre-oil generation zone (0.4-0.5 % R r ) to the stage of dry gas generation (〉 1.3 % R r ). The results of the generic hydrogeochemical modelling indicate a sharp increase of calcite dissolution and the beginning of stylolite formation at approximately 40 °C, which is equivalent to a depth of less than 800 m under hydrostatic conditions considering a geothermal gradient of 30 °C and a surface mean temperature of 20 °C). This temperature corresponds to the pre-oil window when kerogens release an aqueous fluid enriched in carbon dioxide and organic acids. This aqueous fluid may change the existing pore water pH or alkalinity, causes dissolution of carbonate, feldspar and quartz, and clay mineral precipitation along the stylolite. Dissolution of limestone and dolostone leads to re-precipitation of calcite or dolomite opposite of the dissolution side, which indicates only localized mass re-distribution. All these integrated hydrogeochemical processes are coupled to the generation of water during organic matter maturation. In all of the calculated hydrogeochemical scenarios H 2 O is a reaction product and its formation supports the suggested hypothesis. This article is protected by copyright. All rights reserved.

Description: Functional loss of SMN1 causes proximal spinal muscular atrophy (SMA), the most common genetic condition accounting for infant lethality. Hence, the hypomorphic copy gene SMN2 is the only resource of functional SMN protein in SMA patients and influences SMA severity in a dose-dependent manner. Consequently, current therapeutic approaches focus on SMN2 . Histone deacetylase inhibitors (HDACi), such as the short chain fatty acid VPA (valproic acid), ameliorate the SMA phenotype by activating the SMN2 expression. By analyzing blood SMN2 expression in 16 VPA-treated SMA patients, about one-third of individuals were identified as positive responders presenting increased SMN2 transcript levels. In 66% of enrolled patients, a concordant response was detected in the respective fibroblasts. Most importantly, by taking the detour of reprograming SMA patients' fibroblasts, we showed that the VPA response was maintained even in GABAergic neurons derived from induced pluripotent stem cells (iPS) cells. Differential expression microarray analysis revealed a complete lack of response to VPA in non-responders, which was associated with an increased expression of the fatty acid translocase CD36. The pivotal role of CD36 as the cause of non-responsiveness was proven in various in vitro approaches. Most importantly, knockdown of CD36 in SMA fibroblasts converted non- into pos-responders. In summary, the concordant response from blood to the central nervous system (CNS) to VPA may allow selection of pos-responders prior to therapy. Increased CD36 expression accounts for VPA non-responsiveness. These findings may be essential not only for SMA but also for other diseases such as epilepsy or migraine frequently treated with VPA.

Description: : This paper describes polycrystalline diamond from the Erzgebirge ultra-high pressure metamorphic (UHPM) terrane of the Bohemian massif related to the Variscan (340Ma) continent-continent collision. The foils polycrystalline diamond included in zircon were prepared with focused ion beam (FIB) and studied with transmission electron microscopy (TEM). Each domain of the polycrystalline diamond consisted of a series of diamond monocrystals (from 1-4 up to 15) containing numerous nanometric fluid and crystalline inclusions of SiO 2 , CaCO 3 , KCl and KAlSi 3 O 8 . The integrated chemistry of the nanoinclusions suggests that the polycrystalline diamond was crystallized from a mixture of two-end members, which includes a carbon-rich hydrous-silicic fluid containing Si, Al, K and a hydrous-saline fluid rich in Cl, K, Na. Traces of carbonate, sulphate and phosphate coupled with the presence of metallic cations such as Fe, Mg, Ti, Cr, Co, Zn, Zr, Pb, As and Hg found in the diamond are coherent with the local geochemical diversity of the host metasedimentary rocks. The oxidation state of the diamond-forming fluid was close to C-CO buffer, e.g f O 2 = -6 log units, which is at the upper limit of the diamond stability region. The presence of dislocation arrays indicating low-angle grain boundaries together with “zig-zag” features or kinks at diamond grain boundaries reflect rapid crystallization of the polycrystalline diamond. Triangular fluid pockets with steps at the surface related to {110} and {111} planes of diamond could promote the formation of C-H and C-OH bonds that probably could facilitate the process of diamond graphitization. The microstructural features of polycrystalline diamond from the Erzgebirge UHPM terrane as well as their undisputed formation from crustal/organic carbon can be used for better understanding of the origin of any polycrystalline diamond formation from both kimberlitic and alluvial sources, including enigmatic polycrystalline black diamond – commonly called carbonado. © 2012 Blackwell Publishing Ltd

Description: The mineralogy of manganese nodules from the German license area in the eastern Clarion and Clipperton Zone (CCZ) of the central Pacific Ocean was studied using X-ray diffraction. Their individual nanometer to micrometer thick genetically different (hydrogenetic/diagenetic) layer growth structures were investigated using high-resolution transmission electron microscopy. Relationships between the mineral phases and metal content (e.g., Ni+Cu) were assessed with electron microprobe analyzer. The main manganese phase detected in nodules of this study was vernadite, a nanocrystalline and turbostratic phyllomanganate with hexagonal layer symmetry. In layer growth structures of hydrogenetic origin, Fe-vernadite dominates. Layer growth structures of suboxic-diagenetic origin contain three vernadite forms, which are the main Ni and Cu carriers. These Mn-phases were identified on the basis of their structural layer-to-layer distances (7 and 10 Å) and on their capacity to retain these distances when heated. The first form is 7 Å vernadite, which is minor component of the nodules. The second is a thermally unstable ~ 10 Å vernadite collapsing between room temperature and 100 °C, and the third is a thermally stable ~ 10 Å vernadite collapsing between 100 and 300 °C. Todorokite was neither detected in bulk nodules nor in any of the individual suboxic-diagenetic growth structures. Because the mineralogical composition of the nodule is quite homogeneous (only different vernadite-types), it is suggested that the content of Ni and Cu in the individual growth structures is controlled by their availability in the environment during individual growth phases. A profile through a CCZ nodule revealed that the thermal stability of the vernadites change from younger (thermally unstable vernadites, collapsing 〈100 °C) to older growth structures (thermally stable 10 Å vernadites, collapsing 〉100 °C) of the nodule accompanied with changes in type and amount of interlayer cations (e.g., Mg, Na, Ca, K). The stability of the vernadites is probably due to re-organization and incorporation of metals within the interlayer of the crystal structure.

Description: Introduction The world’s biodiversity is in crisis (e.g. Terborgh, 1999; Ceballos et al ., 2010; Cardinale et al ., 2012). Of biodiversity’s various levels, species hold a special place in the imagination of conservationists and the public alike: people equate to them more readily than to elements such as genes and ecosystems. The IUCN Red List of Threatened Species categorises species’ extinction risk (Vié et al ., 2009). Recent comprehensive Red List assessments show high threat levels for amphibians (30% of 6,347 species considered globally threatened), birds (12% of 9,990), mammals (21% of 5,488), cycads (52% of 289), conifers (28% of 620) and freshwater crabs (17% of 1,281 species; but a further 49% of them were listed as Data Deficient) (Cumberlidge et al ., 2009; Hilton-Taylor et al ., 2009). Recent losses far exceed typical ‘background’ extinction rates, those before people dominated the earth (e.g. Baillie et al ., 2004; McCullum, 2007; Ceballos et al ., 2010). Moreover, the Red Li...

Description: 〈p〉Concept cells in the human hippocampus encode the meaning conveyed by stimuli over their perceptual aspects. Here we investigate whether analogous cells in the macaque can form conceptual schemas of spatial environments. Each day, monkeys were presented with a familiar and a novel virtual maze, sharing a common schema but differing by surface features (landmarks). In both environments, animals searched for a hidden reward goal only defined in relation to landmarks. With learning, many neurons developed a firing map integrating goal-centered and task-related information of the novel maze that matched that for the familiar maze. Thus, these hippocampal cells abstract the spatial concepts from the superficial details of the environment and encode space into a schema-like representation.〈/p〉

Description: Introduction The world’s biodiversity is in crisis (e.g. Terborgh, 1999; Ceballos et al ., 2010; Cardinale et al ., 2012). Of biodiversity’s various levels, species hold a special place in the imagination of conservationists and the public alike: people equate to them more readily than to elements such as genes and ecosystems. The IUCN Red List of Threatened Species categorises species’ extinction risk (Vié et al ., 2009). Recent comprehensive Red List assessments show high threat levels for amphibians (30% of 6,347 species considered globally threatened), birds (12% of 9,990), mammals (21% of 5,488), cycads (52% of 289), conifers (28% of 620) and freshwater crabs (17% of 1,281 species; but a further 49% of them were listed as Data Deficient) (Cumberlidge et al ., 2009; Hilton-Taylor et al ., 2009). Recent losses far exceed typical ‘background’ extinction rates, those before people dominated the earth (e.g. Baillie et al ., 2004; McCullum, 2007; Ceballos et al ., 2010). Moreover, the Red Li...

Description: The bacterial flagellar apparatus, which involves ∼40 different proteins, has been a model system for understanding motility and chemotaxis. The bacterial flagellar filament, largely composed of a single protein, flagellin, has been a model for understanding protein assembly. This system has no homology to the eukaryotic flagellum, in which the...

Description: Cordierite–quartz and plagioclase–quartz intergrowths in a paragneiss from northern Labrador (the Tasiuyak Gneiss) were studied using SEM, STEM and TEM. The gneiss experienced granulite-facies conditions and partial melting during both regional and, subsequently, during contact metamorphism. The microstructures examined all result from the contact metamorphism. Cordierite–quartz intergrowths occur on coarse and fine scales. The former sometimes exist as a ‘geometric’ intergrowth in which the interface between cordierite and quartz appears planar at the resolution of the optical microscope and SEM. The latter exist in several microstructural variants. Plagioclase is present as a minor component of the intergrowth in some examples of both the coarse and fine intergrowth. Grain boundaries in cordierite–quartz intergrowths are occupied by amorphous material or a mixture of amorphous material and chlorite. Cordierite and quartz are terminated by crystal faces in contact with amorphous material. Chlorite is sometimes found on cordierite surfaces and penetrating into cordierite grains along defects. Quartz contains (former) fluid inclusions 10 to 20 nanometres in maximum dimension. The presence of planar interfaces between cordierite and the amorphous phase is reminiscent of those between crystals and glass in volcanic rocks but in the absence of compelling evidence that the amorphous material represents former melt, it is interpreted as a reaction product of cordierite. Plagioclase–quartz intergrowths occur in a number of microstructural variants and are commonly associated with cordierite–quartz intergrowths. The plagioclase–quartz intergrowths display simple, non-planar interfaces between plagioclase and quartz. Quartz contains (former) fluid inclusions of dimensions similar to those observed in cordierite–quartz intergrowths. The boundary between quartz and enclosing K-feldspar is cuspate, with quartz cusps penetrating a few tens of nanometres into K-feldspar, commonly along defects in K-feldspar and sometimes with very low dihedral angles at their tips. This cuspate microstructure is interpreted as melt pseudomorphs. The plagioclase–quartz intergrowths share some features with myrmekite but differ in some respects: the composition of the plagioclase (An 37 Ab 62 Or 1 –An 38 Ab 61 Or 1 ); the association with cordierite–quartz intergrowths; and microstructures that are atypical of myrmekite (e.g. quartz vermicules shared with cordierite–quartz intergrowths). It is inferred that the plagioclase–quartz intergrowths may have formed from, or in the presence of, melt. Inferred melt-related microstructures preserved on the nanometre scale suggest that melt on grain boundaries was more pervasive than is evident from light optical and SEM observations. This article is protected by copyright. All rights reserved.