Description: The title compound, [K(C 14 H 23 )(C 4 H 8 O)] n , comprises zigzag chains of alternating bridging 2,3,4,5-tetramethyl-1- n -pentylcyclopentadienyl ligands and potassium ions, with an ancillary tetrahydrofuran ligand in the coordination environment of potassium. The coordination polymer strands so formed extend by 2 1 screw symmetry in the b -axis direction. The chemically modified cyclopentadienyl ligand, with a tethered n -pentyl group, was synthesized from 2,3,4,5-tetramethylcyclopent-2-enone by a Grignard reaction.

Description: Cobbles and boulders on the seafloor are of high ecological value in their function as habitats for a variety of benthic species, contributing to biodiversity and productivity in marine environments. We investigate the origin, physical shape, and structure of habitat-forming cobbles and boulders and reflect on their dynamics in coastal environments of the southwestern Baltic Sea. Stone habitats are not limited to lag deposits and cannot be sufficiently described as static environments, as different dynamic processes lead to changes within the physical habitat structure and create new habitats in spatially disparate areas. Dynamic processes such as (a) ongoing exposure of cobbles and boulders from glacial till, (b) continuous overturning of cobbles, and (c) the migration of cobbles need to be considered. A distinction between allochthonous and autochthonous habitats is suggested. The genesis of sediment types indicates that stone habitats are restricted to their source (glacial till), but hydrodynamic processes induce a redistribution of individual cobbles, leading to the development of new coastal habitats. Thus, coastal stone habitats need to be regarded as dynamic and are changing on a large bandwidth of timescales. In general, wave-induced processes changing the physical structure of these habitats do not occur separately but rather act simultaneously, leading to a dynamic type of habitat.

Description: Subterranean estuaries are connective zones between inland aquifers and the open sea where terrestrial freshwater and circulating seawater mix and undergo major biogeochemical changes. They are biogeochemical reactors that modify groundwater chemistry prior to discharge into the sea. We propose that subterranean estuaries of high-energy beaches are particularly dynamic environments, where the effect of the dynamic boundary conditions propagates tens of meters into the subsurface, leading to strong spatio-temporal variability of geochemical conditions. We hypothesize that they form a unique habitat with an adapted microbial community unlike other typically more stable subsurface environments. So far, however, studies concerning subterranean estuaries of high-energy beaches have been rare and therefore their functioning, and their importance for coastal ecosystems, as well as for carbon, nutrient and trace element cycling, is little understood. We are addressing this knowledge gap within the interdisciplinary research project DynaDeep by studying the combined effect of surface (hydro- and morphodynamics) on subsurface processes (groundwater flow and transport, biogeochemical reactions, microbiology). A unique subterranean estuary observatory was established on the northern beach of the island of Spiekeroog facing the North Sea, serving as an exemplary high-energy research site and model system. It consists of fixed and permanent infrastructure such as a pole with measuring devices, multi-level groundwater wells and an electrode chain. This forms the base for autonomous measurements, regular repeated sampling, interdisciplinary field campaigns and experimental work, all of which are integrated via mathematical modelling to understand and quantify the functioning of the biogeochemical reactor. First results show that the DynaDeep observatory is collecting the intended spatially and temporally resolved morphological, sedimentological and biogeochemical data. Samples and data are further processed ex-situ and combined with experiments and modelling. Ultimately, DynaDeep aims at elucidating the global relevance of these common but overlooked environments.

Description: During mitosis, histone deacetylase 2 (HDAC2) becomes highly phosphorylated through the action of CK2, and HDAC1 and 2 are displaced from mitotic chromosomes. HDAC1 and 2 are components of corepressor complexes, which function with lysine acetyltransferases to catalyze dynamic protein acetylation and regulate gene expression. In this study, we show that HDAC1 and 2 associate with F-actin in mitotic cells. Inhibition of Aurora B or protein kinase CK2 did not prevent the displacement of HDAC1 and 2 from mitotic chromosomes in HeLa cells. Further, proteins of the HDAC1 and 2 corepressor complexes and transcription factors recruiting these corepressors to chromatin were dissociated from mitotic chromosomes independent of Aurora B activity. HDAC1 and 2 returned to the nuclei of daughter cells during lamin A/C reassembly and before Sp1, Sp3 and RNA polymerase II. Our results show that HDAC1 and 2 corepressor complexes are removed from the mitotic chromosomes and are available early in the events leading to the re-establishment of the gene expression program in daughter cells. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.

Description: The ternary Zintl phase EuMgGe was synthesized from the elements, and its structure solved by single-crystal X-ray diffraction. Chemical bonding is discussed, by means of electronic structure calculations at the DFT level and its physical properties characterized with respect to electronic conductivity, magnetic susceptibility, specific heat capacity, and magnetoresistivity. The compound may be interpreted according to the Zintl-Klemm concept as (Eu 2+ )(Mg 2+ )(Ge 4– ) with isolated germanium anions. Resistivity measurements reveal a semimetallic character, which is consistent with the vanishing energy gap obtained from our calculations. The magnetic susceptibility and the specific heat indicate that two consecutive transitions take place, at 9 and 16 K, and they show evidence of magnetic frustration. A possible physical scenario for this magnetic behavior is discussed based on known models of partially frustrated magnets.

Description: Dehydrohedione (DHH) 1 may be obtained in 20% overall yield by a Reformatsky reaction with enone methyl ether 3b , followed by acidic workup of the crude reaction mixture. Alternatively, epoxidation (3-chloroperbenzoic acid, CH 2 Cl 2 , 84% yield) of the tertiary allyl alcohol derivative 4 affords a 1 : 2 mixture of 8a and 8b . The latter epoxy ester 8b may also be obtained stereoselectively either from 4 ( t BuO 2 H, [Mo(CO) 6 ], 1,2-dichloroethane, 70°, 62% yield; or t BuO 2 H, [VO(acac) 2 ], decane, 20°, 92% yield), or from 5 (AcOMe, LiN(SiMe 3 ) 2 , THF, −78°, 84–87%). BF 3 ⋅Et 2 O-Catalyzed cascade rearrangement and OH elimination of 8a afford selectively DHH 1 in 88% yield. The cis disposition of the side chains of the weakly odoriferous hedione-like analogues 2b and 2c was maintained by means of either an epoxy or a cyclopropane moiety.