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Zeng X, Li X, Xu J, Wang X, Deng S, He L, Sun J, Kuang X, Xing X. Structure, electrical properties, and conduction mechanism of new germanate mixed Zn-doped In 2Ge 2O 7 conductors. Inorg Chem Front 2022. [DOI: 10.1039/d2qi00740a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new germanate mixed electronic and oxide ionic conductor In1.8Zn0.2Ge2O6.9 was developed, which exhibits two-dimensional anisotropic transport nature by oxygen exchange between adjacent Ge2O7 units, with a conductivity of 1.62 × 10–2 S cm−1 at 1000 °C.
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Affiliation(s)
- Xiaoling Zeng
- MOE Key Laboratory of New Processing Technology for Nonferrous Metal and Materials, Guangxi Key Laboratory of Optical and Electronic Materials and Devices, Guangxi Universities Key Laboratory of Nonferrous Metal Oxide Electronic Functional Materials and Devices, College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, People's Republic of China
| | - Xiaohui Li
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
- Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, People's Republic of China
- College of Chemistry and Molecular Engineering, Peking University, Beijing National Laboratory for Molecular Science (BNLMS), Beijing 100871, People's Republic of China
| | - Jungu Xu
- MOE Key Laboratory of New Processing Technology for Nonferrous Metal and Materials, Guangxi Key Laboratory of Optical and Electronic Materials and Devices, Guangxi Universities Key Laboratory of Nonferrous Metal Oxide Electronic Functional Materials and Devices, College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, People's Republic of China
| | - Xiaoge Wang
- College of Chemistry and Molecular Engineering, Peking University, Beijing National Laboratory for Molecular Science (BNLMS), Beijing 100871, People's Republic of China
| | - Sihao Deng
- Spallation Neutron Source Science Center, Dongguan 523803, People's Republic of China
| | - Lunhua He
- Spallation Neutron Source Science Center, Dongguan 523803, People's Republic of China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan 523808, People's Republic of China
| | - Junliang Sun
- College of Chemistry and Molecular Engineering, Peking University, Beijing National Laboratory for Molecular Science (BNLMS), Beijing 100871, People's Republic of China
| | - Xiaojun Kuang
- MOE Key Laboratory of New Processing Technology for Nonferrous Metal and Materials, Guangxi Key Laboratory of Optical and Electronic Materials and Devices, Guangxi Universities Key Laboratory of Nonferrous Metal Oxide Electronic Functional Materials and Devices, College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, People's Republic of China
- Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, People's Republic of China
| | - Xianran Xing
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
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Abstract
The thermodynamic behavior of films of hydrated purple membranes from Halobacterium salinarum and the water confined in it was studied by Fourier transform infrared spectroscopy in the 180-280 K range. Unlike bulk water, water in the thin layers sandwiched between the biological membranes does not freeze at 273 K but will be supercooled to approximately 256 K. The melting point is unaffected, leading to hysteresis between 250 and 273 K. In its heating branch, a gradually increasing light-scattering by ice is observed with rate-limiting kinetics of tens of minutes. Infrared (IR) spectra decomposition provided extinction coefficients for the confined water vibrational bands and their changes upon freezing. Because of the hysteresis, at any given temperature in the 255-270 K range, the interbilayer water could be either liquid or frozen, depending on thermal history. We find that this difference affects the dynamics of the bacteriorhodopsin photocycle in the hysteresis range: the decay of the M and N states and the redistribution between them are different depending on whether or not the water was initially precooled to below the freezing point. However, freezing of interbilayer water does block the M to N transition. Unlike the water, the purple membrane lipids do not undergo any IR-detectable phase transition in the 180-280 K range.
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Affiliation(s)
- Andrei K Dioumaev
- Department of Physiology and Biophysics, University of California Irvine, Irvine, CA, USA.
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Holland GP, Alam TM. Multi-dimensional 1H-13C HETCOR and FSLG-HETCOR NMR study of sphingomyelin bilayers containing cholesterol in the gel and liquid crystalline states. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 181:316-26. [PMID: 16798032 DOI: 10.1016/j.jmr.2006.05.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 05/23/2006] [Accepted: 05/31/2006] [Indexed: 05/10/2023]
Abstract
(13)C cross polarization magic angle spinning (CP-MAS) and (1)H MAS NMR spectra were collected on egg sphingomyelin (SM) bilayers containing cholesterol above and below the liquid crystalline phase transition temperature (T(m)). Two-dimensional (2D) dipolar heteronuclear correlation (HETCOR) spectra were obtained on SM bilayers in the liquid crystalline (L(alpha)) state for the first time and display improved resolution and chemical shift dispersion compared to the individual (1)H and (13)C spectra and significantly aid in spectral assignment. In the gel (L(beta)) state, the (1)H dimension suffers from line broadening due to the (1)H-(1)H homonuclear dipolar coupling that is not completely averaged by the combination of lipid mobility and MAS. This line broadening is significantly suppressed by implementing frequency switched Lee-Goldburg (FSLG) homonuclear (1)H decoupling during the evolution period. In the liquid crystalline (L(alpha)) phase, no improvement in line width is observed when FSLG is employed. All of the observed resonances are assignable to cholesterol and SM environments. This study demonstrates the ability to obtain 2D heteronuclear correlation experiments in the gel state for biomembranes, expands on previous SM assignments, and presents a comprehensive (1)H/(13)C NMR assignment of SM bilayers containing cholesterol. Comparisons are made to a previous report on cholesterol chemical shifts in dimyristoylphosphatidylcholine (DMPC) bilayers. A number of similarities and some differences are observed and discussed.
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Affiliation(s)
- Gregory P Holland
- Department of Electronic and Nanostructured Materials, Sandia National Laboratories, Albuquerque, NM 87185-0886, USA
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Mannock DA, McIntosh TJ, Jiang X, Covey DF, McElhaney RN. Effects of natural and enantiomeric cholesterol on the thermotropic phase behavior and structure of egg sphingomyelin bilayer membranes. Biophys J 2003; 84:1038-46. [PMID: 12547785 PMCID: PMC1302681 DOI: 10.1016/s0006-3495(03)74920-0] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phospholipids, sphingolipids, and sterols are the major lipid components of the plasma membranes of eukaryotic cells. Because these three lipid classes occur naturally as enantiomerically pure compounds, enantiospecific lipid-lipid and lipid-sterol interactions could in principle occur in the lipid bilayers of eukaryotic plasma membranes. Although previous biophysical studies of phospholipid and phospholipid-sterol model membrane systems have consistently failed to observe such enantiomerically selective interactions, a recent monolayer study of the interactions of natural and enantiomeric cholesterol with egg sphingomyelin has apparently revealed the existence of enantiospecific sterol-sphingolipid interactions. To determine whether enantiospecific sterol-sphingolipid interactions also occur in more biologically relevant lipid-bilayer systems, differential scanning calorimetric, x-ray diffraction, and neutral buoyant-density measurements were utilized to study the effects of natural and enantiomeric cholesterol on the thermotropic phase behavior and structure of egg sphingomyelin bilayers. The calorimetry experiments show that the natural and enantiomeric cholesterol have essentially identical effects on the temperature, enthalpy, and cooperativity of the gel/liquid-crystalline phase transition of egg sphingomyelin bilayers within the limits of experimental error. As well, the x-ray diffraction and neutral buoyancy experiments indicate that bilayers formed from mixtures of natural or enantiomeric cholesterol and egg sphingomyelin have, within experimental uncertainty, the same structure and mass density. We thus conclude that significant enantioselective cholesterol-sphingolipid interactions do not occur in this lipid-bilayer model membrane system.
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Affiliation(s)
- David A Mannock
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2H7 Canada
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Koynova R, Caffrey M. Phases and phase transitions of the phosphatidylcholines. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1376:91-145. [PMID: 9666088 DOI: 10.1016/s0304-4157(98)00006-9] [Citation(s) in RCA: 786] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
LIPIDAT (http://www.lipidat.chemistry.ohio-state.edu) is an Internet accessible, computerized relational database providing access to the wealth of information scattered throughout the literature concerning synthetic and biologically derived polar lipid polymorphic and mesomorphic phase behavior and molecular structures. Here, a review of the data subset referring to phosphatidylcholines is presented together with an analysis of these data. This subset represents ca. 60% of all LIPIDAT records. It includes data collected over a 43-year period and consists of 12,208 records obtained from 1573 articles in 106 different journals. An analysis of the data in the subset identifies trends in phosphatidylcholine phase behavior reflecting changes in lipid chain length, unsaturation (number, isomeric type and position of double bonds), asymmetry and branching, type of chain-glycerol linkage (ester, ether, amide), position of chain attachment to the glycerol backbone (1,2- vs. 1,3-) and head group modification. Also included is a summary of the data concerning the effect of pressure, pH, stereochemical purity, and different additives such as salts, saccharides, amino acids and alcohols, on phosphatidylcholine phase behavior. Information on the phase behavior of biologically derived phosphatidylcholines is also presented. This review includes 651 references.
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Affiliation(s)
- R Koynova
- Institute of Biophysics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Koynova R, Caffrey M. Phases and phase transitions of the sphingolipids. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1255:213-36. [PMID: 7734437 DOI: 10.1016/0005-2760(94)00202-a] [Citation(s) in RCA: 141] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
LIPIDAT is a computerized database providing access to the wealth of information scattered throughout the literature concerning synthetic and biologically derived polar lipid polymorphic and mesomorphic phase behavior. Herein, we present a review of the LIPIDAT data subset referring to sphingolipids together with an analysis of these data. It includes data collected over a 40-year period and consists of 867 records obtained from 112 articles in 25 different journals. An analysis of these data has allowed us to identify trends in hydrated sphingolipid phase behavior reflecting differences in fatty acyl chain length, saturation and hydroxylation, head group type, and sphingoid base identity. Information on the mesomorphism of biologically-derived and dry sphingolipids is also presented. This review includes 161 references.
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Affiliation(s)
- R Koynova
- Department of Chemistry, Ohio State University, Columbus, 43210-1173, USA
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