High-resolution photoemission has been used to study the electronic structure of the charge density wave and superconducting dichalcogenide, 2H-NbSe2. From the extracted self-energies, important components of the quasiparticle interactions have been identified. In contrast to previously studied TaSe2, the CDW transition does not affect the electronic properties significantly. The electronphonon coupling is identified as a dominant contribution to the QP self-energy and is shown to be very anisotropic (k-dependent) and much stronger than in TaSe2.

Abstract. We have explored the dynamics of intermediate filament assembly and subunit exchange using fluorescently labeled neurofilament proteins and a fluorescence resonance energy transfer assay. Neurofilaments (NFs) are assembled from three highly phosphorylated proteins with molecular masses of 180 (NF-H), 130 (NF-M), and 66 kD (NF-L) of which NF-L forms the structural core. The core component, NF-L, was stoichiometrically labeled at cysteine 321 with fluorescein, coumarin, or biotin-maleimide to produce assembly-competent fluorescent or biotinylated derivatives, respectively. Using coumarinlabeled NF-L as fluorescence donor and fluoresceinlabeled NF-L as the fluorescence acceptor, assembly of NF filaments was induced by rapidly raising the NaCI concentration to 170 mM, and the kinetics was followed by the decrease in the donor fluorescence. Assembly of NF-L subunits into filaments does not require nucleotide binding or hydrolysis but is strongly dependent on ionic strength, pH, and temperature. The critical concentration of NF-L, that concentration that remains unassembled at equilibrium with fully formed filaments, is 38/zg/ml or 0.6/~M. Under physiological salt conditions NF-L filaments also undergo extensive subunit exchange. Kinetic analysis and evaluation of several possible mechanisms indicate that subunit exchange is preceded by dissociation of subunits from the filament and generation of a kinetically active pool of soluble subunits. Given the concentration of NF-L found in nerve cells and the possibility of regulating this pool, these results provide the first information that intermediate filaments are dynamic structures and that NF-L within the NF complex is in dynamic equilibrium with a small but kinetically active pool of unassembled NF-L units.

For any given level of overall adiposity, individuals vary considerably in fat distribution. The inherited basis of fat distribution in the general population is not fully understood. Here, we study up to 38,965 UK Biobank participants with MRI-derived visceral (VAT), abdominal subcutaneous (ASAT), and gluteofemoral (GFAT) adipose tissue volumes. Because these fat depot volumes are highly correlated with BMI, we additionally study six local adiposity traits: VAT adjusted for BMI and height (VATadj), ASATadj, GFATadj, VAT/ASAT, VAT/GFAT, and ASAT/GFAT. We identify 250 independent common variants (39 newly-identified) associated with at least one trait, with many associations more pronounced in female participants. Rare variant association studies extend prior evidence for PDE3B as an important modulator of fat distribution. Local adiposity traits (1) highlight depot-specific genetic architecture and (2) enable construction of depot-specific polygenic scores that have divergent associations with type 2 diabetes and coronary artery disease. These results – using MRI-derived, BMI-independent measures of local adiposity – confirm fat distribution as a highly heritable trait with important implications for cardiometabolic health outcomes.

6-Carboxyfluorescein was employed to examine the effect of alcohol-induced lipid interdigitation on proton permeability in L-alpha-dipalmitoylphosphatidylcholine (DPPC) large unilamellar vesicles. Proton permeability was measured by monitoring the decrease of 6-carboxyfluorescein fluorescence after a pH gradient from 3.5 (outside the vesicle) to 8.0 (inside the vesicle) was established. At 20 degrees C and below 1.2 M ethanol, the fluorescence decrease is best described by a single exponential function. Above 1.2 M ethanol, the intensity decrease is better described by a two-exponential decay law. Using the fitted rate constants and the vesicle radii determined from light-scattering measurements, the proton permeability coefficient, P, in DPPC vesicles was calculated as a function of ethanol concentration. At 20 degrees C, P increases monotonically with increasing ethanol content up to 1.0 M, followed by an abrupt increase at 1.2 M. The vesicle size also exhibits a sudden increase at around 1.2 M ethanol, which has been shown to result from vesicle aggregation rather than vesicle fusion. The abrupt increases in P and in vesicle size occur at the concentration region close to the critical ethanol concentration for the formation of the fully interdigitated gel state of DPPC. At 14 degrees C, the abrupt change in P shifts to 1.9-2.0 M ethanol, completely in accordance with the ethanol-temperature phase diagram of interdigitated DPPC. Effects of methanol and benzyl alcohol on lipid interdigitation have also been examined. At 20 degrees C, DPPC large unilamellar vesicles exhibit a dramatic change in P at 3 M methanol and at 40 mM benzyl alcohol. These concentrations come close to the critical methanol and benzyl alcohol concentrations for the formation of fully interdigitated DPPC structures determined previously by others. It can be concluded that proton permeability increases dramatically as DPPC is transformed from the noninterdigitated gel to the fully interdigitated gel state by high concentrations of alcohol. This marked increase in proton permeability can be attributed to the combined effect of the changes in membrane thickness and surface charge density, due to the ethanol-induced lipid interdigitation. The possible effects of the increased proton permeability caused by ingested ethanol on gastric mucosal membranes are discussed.

Both in vivo and in vitro, neuroframents (NFs) are among the most highly phosphorylated proteins known. The majority of the NF phosphorylation sites reside on the carboxyl-terminal tails of the proteins. We have isolated and characterized an effector-independent neurofflamentspecific protein kinase from bovine spinal cord that is associated with the NF complex and exhibits a marked substrate specificity for NF-H, the largest subunit of the NF triplet. This kinase activity emerges from a NF-conjugated affmity column coincident with a 67-kDa doublet on NaDodSO4/polyacrylamide gels and has a purity of >90%. The purified enzyme exclusively phosphorylates NF-H tails and is dependent on prior phosphorylation of this molecule. The enzyme is also not autophosphorylated. While the molecular properties and substrate specificities of the NF kinase distinguish it from cAMPdependent protein kinase, protein kinase C, Ca2+/calmodulin kinase, and casein kinases I and II, it exhibits certain properties similar to, but different from, the growth-associated histone HI kinase. The molecular properties and specific sequence requirements ofthe NF kinase suggest that this enzyme could play a pivotal role in the phosphorylation of NFs in normal and pathological states such as Alzheimer disease, where NFs are hvnernhnenharv Atd.Nerve cell intermediate filaments, or neurofilaments (NFs), are composed of three proteins of low (66 kDa; NF-L), medium (130 kDa; NF-M), and high (180 kDa; NF-H) molecular masses (1, 2). While the three NF subunits share a highly conserved a-helical rod region with other intermediate filament proteins, NF-H and NF-M differ in that they each possess a highly acidic carboxyl-terminal tail domain. NF-M and NF-H MATERIALS AND METHODS Chemicals. The following protease inhibitors at 1 pug/ml were included in all preparative buffers: pepstatin, leupeptin, N2-(p-tosyl)-L-lysine chloromethyl ketone, and L-1-tosylamido-2-phenylethyl chloromethyl ketone; and 0.2 mM phenylmethylsulfonyl fluoride was also added.Neurorflaments and Purified Subunits. NF-enriched fractions and purified subunits (NF-H, NF-M, and NF-L) were prepared from fresh bovine spinal cord as described (2).NF-enriched cytoskeletal proteins and resolved NF subunits were dephosphorylated by incubation with 2-20 units of Escherichia coli alkaline phosphatase per mg of NF protein for various times ranging from 5 min to 18 hr (6). Dephosphorylated subunits were brought to 50 mM EDTA, boiled, and dialyzed against 50 mM 2-(N-morpholino)ethanesulfonic acid (Mes; pH 6.5) prior to assay.Phosphorylated NF-H was digested with chymotrypsin at an enzyme/NF-H ratio of 1:400 (wt/wt) for 15 min at 220C (9).Under these conditions NF-H is cleaved into two fragments, a 40-kDa rod and a 160-kDa tail. Microtubules (MT) and microtubule-associated proteins (MAPs) were prepared by using temperature-dependent cycles of assembly/disassembly (10 During the purification, the specific activity of the enzyme was monitored by assaying 1 ,ug of purified NF-H under the same condit...

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A Comment on the Letter by D. Pacilé et al., Phys. Rev. Lett. 101, 066806 (2008)10.1103/PhysRevLett.101.066806. The authors of the Letter offer a Reply.

PACS 74.72.-h-Cuprate superconductors (high-Tc and insulating parent compounds) PACS 71.10.Li-Excited states and pairing interactions in model systems PACS 71.20.-b-Electron density of states and band structure of crystalline solids Abstract-Multiple Zhang-Rice type spectral features have been observed in resonant inelastic X-ray scattering (RIXS) from the quasi-one-dimensional cuprate charge transfer insulator Li2CuO2. The first feature appears at constant emission energy, and is associated with a Zhang-Rice singlet final state. The second is an interplaquette charge transfer excitation that results in a novel triplet Zhang-Rice-type final state. It is accompanied by the presence of a O 2p nonbonding to upper Hubbard band excitation at an energy close to that of a calculated triplet charge transfer Zhang-Rice-type excitation. The site selectivity and polarization rules associated with RIXS allows these two excitations to be distinguished.