Function,expression and localization of annexin A7 in platelets and red blood cells: Insights derived from an annexin A7 mutant mouse

Background  

Annexin A7 is a Ca²⁺- and phospholipid-binding protein expressed as a 47 and 51 kDa isoform, which is thought to be involved in membrane fusion processes. Recently the 47 kDa isoform has been identified in erythrocytes where it was proposed to be a key component in the process of the Ca²⁺-dependent vesicle release, a process with which red blood cells might protect themselves against an attack by for example complement components.     

A traditional synthetic method, and a new structural motif, for molybdenum-gold clusters: synthesis and solid-state structure of Au8{Mo(CO)5}4(PPh3)4

The neutral cluster [Au8Mo4(CO)20(PPh3)4] was synthesized in low yield from [AuCl(PPh3)] and [Mo2(CO)10]2- in acetonitrile at room temperature. The cluster was characterized by X-ray analysis, IR, and 31P NMR spectroscopy. Its solid-state structure consists of four Au(3)Mo tetrahedral units, fused by four Au atoms in a ring. The average bond lengths are Au-Au 2.77 Angstrom and Mo-Au 2.93 Angstrom. The internal angles of the planar square ring are very close to 90 degrees.     

Mixed Ruthenium–Iridium Carbonyl Cluster Complexes. Synthesis of the Anions [Ru3Ir2(CO)14]2− and [Ru3Ir2(CO)14H]− and Crystal Structures of Their [tetraphenylphosphonium]+ Salts

The reaction of Ru₃(CO)₁₂ and [Ir(CO)₄]^- (as [PPh₄]⁺ or [N(PPh₃)₂]⁺ salts) yields the anion [Ru₃Ir₂(CO)₁₄]^2- (1) which has been found to derive from the intermediate [Ru₃Ir(CO)₁₃]^- anion. Treatment of (1) with acids gives the conjugated hydrido species [Ru₃Ir₂(CO)₁₄H]^- (2). The two anions were characterized by single-crystal X-ray diffraction of their [PPh₄]⁺ salts. [PPh₄]₂[Ru₃Ir₂(CO)₁₄]: space group C2/c, Z=4, a=22.121(5) Å, b=10.546(5) Å, c=25.931(5) Å, =103.870(5)°, R=0.052 and R_w=0.130 for 3128 independent reflections with I>2(I ). [PPh₄][Ru₃Ir₂(CO)₁₄H]: space group P2₁/c, Z=8, a=22.833(5) Å, b=13.893(5) Å, c=25.810(5) Å, =92.650(5)°, R=0.070 and R_w=0.150 for 12141 independent reflections with I>2(I). Both anions 1 and 2 have a trigonal bipyramidal metal frame. There are two independent anions in the asymmetric unit of 2 differing in their ligand stereochemistry.     

Surface Dynamics of A Vanadyl Pyrophosphate Catalyst for n‐Butane Oxidation to Maleic Anhydride: An In Situ Raman and Reactivity Study of the Effect of the P/V Atomic Ratio

This work focused on investigating the effect of the P/V atomic ratio in vanadyl pyrophosphate, catalyst for n‐butane oxidation to maleic anhydride, on the nature of the catalytically active phase. Structural transformations occurring on the catalyst surface were investigated by means of in situ Raman spectroscopy in a non‐reactive atmosphere, as well as by means of steady‐state and non‐steady‐state reactivity tests, in response to changes in the reaction temperature. It was found that the nature of the catalyst surface is affected by the P/V atomic ratio even in the case of small changes in this parameter. With the catalyst having P/V equal to the stoichiometric value, a surface layer made of α_I‐VOPO₄ developed in the temperature interval 340–400 °C in the presence of air; this catalyst gave a very low selectivity to maleic anhydride in the intermediate T range (340–400 °C). However, at 400–440 °C δ‐VOPO₄ overlayers formed; at these conditions, the catalyst was moderately active but selective to maleic anhydride. With the catalyst containing a slight excess of P, the ratio offering the optimal catalytic performance, δ‐VOPO₄ was the prevailing species over the entire temperature range investigated (340–440 °C). Analogies and differences between the two samples were also confirmed by reactivity tests carried out after in situ removal and reintegration of P. These facts explain why the industrial catalyst for n‐butane oxidation holds a slight excess of P; they also explain discrepancies registered in the literature about the nature of the active layer in vanadyl pyrophosphate.     

Neutral substituted carbonyl clusters of iridium. Synthesis and X-ray characterization of tri-μ3-carbonyl-μ-carbonylheptacarbonylpentakis(trimethylphosphite)-octahedro-hexairidium

The reaction of Ir₆(CO)₁₆ with P(OMe)₃ in toluene yields Ir₆(CO)₁₁ [P(OMe)₃]₅ which has been shown by X-ray diffraction to contain an octahedral cluster of iridium atoms bearing five terminal trimethylphosphite ligands, three face-bridging, one edge-bridging and seven terminal carbonyl groups.     

Synthesis of mesoporous carbons and reduced graphene oxide and their influence on the cycling performance of rechargeable Li-O<Subscript>2</Subscript> batteries

In the lithium-oxygen (Li-O₂) cell, the porous structure of the cathode is an important issue as well as challenge for its task of accommodating discharge products and providing free paths for oxygen. Clogging of pores and degradation of materials at the cathode affect the discharge rates and cycling performance of Li-O₂ cell. Based on the study of five synthesized nanostructured porous carbons, namely, 2-D ordered mesoporous carbon C-15, 3-D ordered mesoporous carbons C-16 and C-16B with larger pores, hollow core mesoporous shell carbon (HCMSC), and reduced graphene oxide (rGO), we found that the type and pore structure of the carbon significantly affect the electrochemical performance of the cell. Both C-15 and rGO cathodes demonstrate good cell cycleability, while the HCMSC, with its interesting bimodal pore system, is not favorable for further improving cycling performance. The C-16B has similar morphology and electrolyte wettability of C-16. However, the former possesses larger pores, and such porosity significantly improves the cell cycleability up to 44 cycles, corresponding to an extended operation life of 850 h.

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Strongly stable bases for adaptively refined multilevel spline spaces

The problem of constructing a normalized hierarchical basis for adaptively refined spline spaces is addressed. Multilevel representations are defined in terms of a hierarchy of basis functions, reflecting different levels of refinement. When the hierarchical model is constructed by considering an underlying sequence of bases $\{\Gamma ^{\ell }\}_{\ell =0,\ldots ,N-1}$ with properties analogous to classical tensor-product B-splines, we can define a set of locally supported basis functions that form a partition of unity and possess the property of coefficient preservation, i.e., they preserve the coefficients of functions represented with respect to one of the bases $\Gamma ^{\ell }$ . Our construction relies on a certain truncation procedure, which eliminates the contributions of functions from finer levels in the hierarchy to coarser level ones. Consequently, the support of the original basis functions defined on coarse grids is possibly reduced according to finer levels in the hierarchy. This truncation mechanism not only decreases the overlapping of basis supports, but it also guarantees strong stability of the construction. In addition to presenting the theory for the general framework, we apply it to hierarchically refined tensor-product spline spaces, under certain reasonable assumptions on the given knot configuration.     

New highlights on degradation process of verdigris from easel paintings

Verdigris is a green copper organometallic pigment, widely used in paintings during the fifteenth and sixteenth centuries. With ageing, chromatic modifications like browning or darkening can be observed on those green painted layers. An original but crucial approach has been developed based on the characterization of a reference neutral verdigris pigment—anhydrous copper acetate—and model samples, made of verdigris and linseed oil. Samples have undergone artificial ageing (temperature, light) to reproduce the color change effect. They were analysed before and after accelerated ageing tests by a complementary set of classical techniques: colorimetry, electron paramagnetic resonance, X-ray absorption spectroscopy, and UV–visible absorption. Our experiments revealed that the incorporation of the verdigris pigment in linseed oil induces a transformation of the copper acetate bimetallic structure, with the formation of monomeric species. These monomers, however, are not directly responsible for the darkening. The chromatic alteration seems instead linked to the transient formation of Cu(I) in the copper complexes of the pigment/oil system. This formation could be initiated by ambient light absorption through ligand-to-metal charge transfer, which favors the decarboxylation of the copper complexes leading to the reduction of Cu(II) into Cu(I). Moreover, dioxygen can react with partially decarboxylated dimers to form peroxy-Cu dimer complexes that can be responsible for the darkening.