1,658 research outputs found
Tetrakis(acetonitrile-κN)lithium hexafluoridophosphate acetonitrile monosolvate
In the title compound, [Li(CH3CN)4]PF6·CH3CN, the asymmetric unit consists of three independent tetrahedral [Li(CH3CN)4]+ cations, three uncoordinated PF6
− anions and three uncoordinated CH3CN solvent molecules. The three anions are disordered over two sites through a rotation along one of the F—P—F axes. The relative occupancies of the two sites for the F atoms are 0.643 (16):0.357 (16), 0.677 (10):0.323 (10) and 0.723 (13):0.277 (13). The crystal used was a racemic twin, with approximately equal twin components
Lithium bis(2-methyllactato)borate monohydrate
The title compound {systematic name: poly[[aqualithium]-μ-3,3,8,8-tetramethyl-1,4,6,9-tetraoxa-5λ4-borataspiro[4.4]nonane-2,7-dione]}, [Li(C8H12BO6)(H2O)]n (LiBMLB), forms a 12-membered macrocycle, which lies across a crystallographic inversion center. The lithium cations are pseudo-tetrahedrally coordinated by three methyllactate ligands and a water molecule. The asymmetric units couple across crystallographic inversion centers, forming the 12-membered macrocycles. These macrocycles, in turn, cross-link through the Li+ cations, forming an infinite polymeric structure in two dimensions parallel to (101)
Poly[[(acetonitrile)lithium(I)]-μ3-tetrafluoridoborato]
The structure of the title compound, [Li(BF4)(CH3CN)]n, consists of a layered arrangement parallel to (100) in which the Li+ cations are coordinated by three F atoms from three tetrafluoridoborate (BF4
−) anions and an N atom from an acetonitrile molecule. The BF4
− anion is coordinated to three different Li+ cations though three F atoms. The structure can be described as being built from vertex-shared BF4 and LiF3(NCCH3) tetrahedra. These tetrahedra reside around a crystallographic inversion center and form 8-membered rings
Poly[bis(acetonitrile-κN)bis[μ3-bis(trifluoromethanesulfonyl)imido-κ4 O,O′:O′′:O′′′]dilithium]
In the title compound, [Li2(CF3SO2NSO2CF3)2(CH3CN)2]n, two Li+ cations reside on crystallographic inversion centers, each coordinated by six O atoms from bis(trifluoromethanesulfonyl)imide (TFSI−) anions. The third Li+ cation on a general position is four-coordinated by two anion O atoms and two N atoms from acetonitrile molecules in a tetrahedral geometry
Poly[diacetonitrile[μ3-difluoro(oxalato)borato]sodium]
The title compound, [Na(C2BF2O4)(CH3CN)2]n, forms infinite two-dimensional layers running parallel to (010). The layers lie across crystallographic mirror planes at y = 1/4 and 3/4. The Na, B and two F atoms reside on these mirror planes. The Na+ cations are six-coordinate. Two equatorial coordination positions are occupied by acetonitrile molecules. The other two equatorial coordination sites are occupied by the chelating O atoms from the difluoro(oxalato)borate anion (DFOB−). The axial coordination sites are occupied by two F atoms from two different DFOB− anions
Lithium difluoro(oxalato)borate tetramethylene sulfone disolvate
The title compound, Li+·C2BF2O4
−·2C4H8O2S, is a dimeric species, which resides across a crystallographic inversion center. The dimers form eight-membered rings containing two Li+ cations, which are joined by O2S sulfone linkages. The Li+ cations are ligated by four O atoms from the anions and solvent molecules, forming a pseudo-tetrahedral geometry. The exocyclic coordination sites are occupied by O atoms from the oxalate group of the difluoro(oxalato)borate anion and an additional tetramethylene sulfone ligand
The Impact of Li Grain Size on Coulombic Efficiency in Li Batteries
One of the most promising means to increase the energy density of state-of-the-art lithium Li-ion batteries is to replace the graphite anode with a Li metal anode. While the direct use of Li metal may be highly advantageous, at present its practical application is limited by issues related to dendrite growth and low Coulombic efficiency, CE. Here operando electrochemical scanning transmission electron microscopy (STEM) is used to directly image the deposition/stripping of Li at the anode-electrolyte interface in a Li-based battery. A non-aqueous electrolyte containing small amounts of H2O as an additive results in remarkably different deposition/stripping properties as compared to the “dry” electrolyte when operated under identical electrochemical conditions. The electrolyte with the additive deposits more Li during the first cycle, with the grain sizes of the Li deposits being significantly larger and more variable. The stripping of the Li upon discharge is also more complete, i.e., there is a higher cycling CE. This suggests that larger grain sizes are indicative of better performance by leading to more uniform Li deposition and an overall decrease in the formation of Li dendrites and side reactions with electrolyte components, thus potentially paving the way for the direct use of Li metal in battery technologies
Structure and function of the bacterial heterodimeric ABC transporter CydDC: stimulation of ATPase activity by thiol and heme compounds.
In Escherichia coli, the biogenesis of both cytochrome bd-type quinol oxidases and periplasmic cytochromes requires the ATP-binding cassette-type cysteine/GSH transporter, CydDC. Recombinant CydDC was purified as a heterodimer and found to be an active ATPase both in soluble form with detergent and when reconstituted into a lipid environment. Two-dimensional crystals of CydDC were analyzed by electron cryomicroscopy, and the protein was shown to be made up of two non-identical domains corresponding to the putative CydD and CydC subunits, with dimensions characteristic of other ATP-binding cassette transporters. CydDC binds heme b. Detergent-solubilized CydDC appears to adopt at least two structural states, each associated with a characteristic level of bound heme. The purified protein in detergent showed a weak basal ATPase activity (approximately 100 nmol Pi/min/mg) that was stimulated ∼3-fold by various thiol compounds, suggesting that CydDC could act as a thiol transporter. The presence of heme (either intrinsic or added in the form of hemin) led to a further enhancement of thiol-stimulated ATPase activity, although a large excess of heme inhibited activity. Similar responses of the ATPase activity were observed with CydDC reconstituted into E. coli lipids. These results suggest that heme may have a regulatory role in CydDC-mediated transmembrane thiol transport
Dark Matter Time Projection Chamber : Recent R&D Results
The Dark Matter Time Projection Chamber collaboration recently reported a dark matter limit obtained with a 10 liter time projection chamber filled with CF[subscript 4] gas. The 10 liter detector was capable of 2D tracking (perpendicular to the drift direction) and 2D fiducialization, and only used information from two CCD cameras when identifying tracks and rejecting backgrounds. Since that time, the collaboration has explored the potential benefits of photomultiplier tube and electronic charge readout to achieve 3D tracking, and particle identification for background rejection. The latest results of this effort is described here
Human SNP links differential outcomes in inflammatory and infectious disease to a FOXO3-regulated pathway
The clinical course and eventual outcome, or prognosis, of complex diseases varies enormously between affected individuals. This variability critically determines the impact a disease has on a patient’s life but is very poorly understood. Here, we exploit existing genome-wide association study data to gain insight into the role of genetics in prognosis. We identify a noncoding polymorphism in FOXO3A (rs12212067: T > G) at which the minor (G) allele, despite not being associated with disease susceptibility, is associated with a milder course of Crohn’s disease and rheumatoid arthritis and with increased risk of severe malaria. Minor allele carriage is shown to limit inflammatory responses in monocytes via a FOXO3-driven pathway, which through TGFβ1 reduces production of proinflammatory cytokines, including TNFα, and increases production of anti-inflammatory cytokines, including IL-10. Thus, we uncover a shared genetic contribution to prognosis in distinct diseases that operates via a FOXO3-driven pathway modulating inflammatory responses. PAPERCLIP
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