Biological maturation and β-adrenergic effectors: development of β-adrenergic receptors in rabbit heart

The β-adrenergic receptor, transduction processes and catalytic activity of the adenylate cyclase enzyme complex have been investigated in rabbit heart at different stages of biological maturation. The binding of [ 3 H]-dihydroalprenolol to a washed membrane preparation isolated from rabbit ventricular muscle was used to characterize β-adrenergic receptors. Significant age-related differences were noted in β-receptor affinity (K d ) and density (RD) of neonatal and adult animals; the adult K d was 3.7-fold greater and the RD 2-fold higher than the neonates. No significant differences in these parameters were detected among the 27-day old fetus and the 1- and 7-day old neonates. Age-dependent differences in agonist isoproterenol affinity for the receptor were not observed in contrast to the significant changes in antagonist (DHA) affinity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45349/1/11010_2004_Article_BF00240617.pd

Comprehensive study of the CuF<inf>2</inf> conversion reaction mechanism in a lithium ion battery

Conversion materials for lithium ion batteries have recently attracted considerable attention due to their exceptional specific capacities. Some metal fluorides, such as CuF2, are promising candidates for cathode materials owing to their high operating potential, which stems from the high electronegativity of fluorine. However, the high ionicity of the metal–fluorine bond leads to a large band gap that renders these materials poor electronic conductors. Nanosizing the active material and embedding it within a conductive matrix such as carbon can greatly improve its electrochemical performance. In contrast to other fluorides, such as FeF2 and NiF2, good capacity retention has not, however, been achieved for CuF2. The reaction mechanisms that occur in the first and subsequent cycles and the reasons for the poor charge performance of CuF2 are studied in this paper via a variety of characterization methods. In situ pair distribution function analysis clearly shows CuF2 conversion in the first discharge. However, few structural changes are seen in the following charge and subsequent cycles. Cyclic voltammetry results, in combination with in situ X-ray absorption near edge structure and ex situ nuclear magnetic resonance spectroscopy, indicate that Cu dissolution is associated with the consumption of the LiF phase, which occurs during the first charge via the formation of a Cu1+ intermediate. The dissolution process consequently prevents Cu and LiF from transforming back to CuF2. Such side reactions result in negligible capacity in subsequent cycles and make this material challenging to use in a rechargeable battery.We acknowledge the funding from the U.S. DOE BES via funding to the EFRC NECCES, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001294 (support for Rosa Robert and Lin-Shu Du) and EPSRC via the “nanoionics” programme grant (support for Xiao Hua). Use of the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory (BNL), was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.This is the final published version of the article. It first appeared at http://pubs.acs.org/doi/abs/10.1021/jp503902z and is posted here under the terms of ACS's Editors' Choice scheme (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html)

Characterization of Ni/C Multilayers with Fluorescence XAFS Experiments at Fixed Standing Wave Field Positions

A ninefold Ni/C multilayer is characterized by X-ray reflectometry and fluorescence XAFS (X-ray absorption fine structure) combined in one experiment. Synchrotron radiation and a standing wave field which occurs for reflection at the first Bragg reflection order of the multilayer are used. A defined shift of the standing wave field position leads to different weights of absorption and hence fluorescence contributions of the atoms within the layers. Thus it is possible to investigate the neighbourhood of the Ni atoms in dependence on their depth position within the Ni layer

Pulsed laser deposition of x-Ray optical layer stacks with atomically flat interfaces

Pulsed laser deposition is described as a technique for the synthesis of multilayer showing X-ray optical quality. The state of the art is characterized by results that demonstrate a development of the instrumental basis superior to that of conventional PLD systems. Multilayers of the Ni/C-, Mo/Si- and W/C-types prove the versatility of the method and the output of layer stack characterization by HREM SPM, XD, AES, XPS, ellipsometry and image processing ensures a high quality with regard to stack regularity, layer homogeneity and interface smoothness

Fluorinated (Nano)Carbons: CF x Electrodes and CF x ‐Based Batteries

International audienceFluorine‐based chemistry is widely used in commercial battery technology, from primary batteries consisting of Li/CFx to binders for electrodes in secondary lithium‐ion batteries. Fluorine‐based compounds are also formed during operation for both battery configurations as discharge products such as LiF or as components of the solid electrolyte interface (SEI) layers on electrodes. Herein, the fluorinated carbons or CFx detailing the commercialization of the first Li/CFx cells are discussed‐ the understanding of how performance is correlated to composition or x, the various methods to synthesize CFx compounds, the correlation between the nature of the C-F bonds and electrochemical performance, the role of theoretical studies in such endeavors, the use of CFx in alternative battery chemistries and the wide range of techniques available to probe either CFx compounds individually or CFx compounds in devices under electrochemical conditions. A picture of the field from which future directions can be derived is provided