The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Hideo Hosono - One of the best experts on this subject based on the ideXlab platform.
-
two dome structure in electron Doped iron arsenide superconductors
Nature Communications, 2012Co-Authors: Soshi Iimura, Satoru Matsuishi, Hikaru Sato, Taku Hanna, Yoshinori Muraba, Masaki Takata, Hideo HosonoAbstract:The iron pnictides are a class of superconductors that have received widespread interest in recent years. By doping the prototypical material LaFeAsO with hydrogen, this study reveals the existence of a second superconducting dome at higher doping ranges, which arises due to orbital fluctuations.
-
two dome structure in electron Doped iron arsenide superconductors
Nature Communications, 2012Co-Authors: Soshi Iimura, Satoru Matsuishi, Hikaru Sato, Taku Hanna, Yoshinori Muraba, Masaki Takata, Sung Wng Kim, Jungeun Kim, Hideo HosonoAbstract:Iron arsenide superconductors based on the material LaFeAsO(1-x)F(x) are characterized by a two-dimensional Fermi surface (FS) consisting of hole and electron pockets yielding structural and antiferromagnetic transitions at x=0. Electron doping by substituting O(2-) with F(-) suppresses these transitions and gives rise to superconductivity with a maximum T(c) of 26 K at x=0.1. However, the over-Doped region cannot be accessed due to the poor solubility of F(-) above x=0.2. Here we overcome this problem by doping LaFeAsO with hydrogen. We report the phase diagram of LaFeAsO(1-x)H(x) (x<0.53) and, in addition to the conventional superconducting dome seen in LaFeAsO(1-x)F(x), we find a second dome in the range 0.21
Soshi Iimura - One of the best experts on this subject based on the ideXlab platform.
-
two dome structure in electron Doped iron arsenide superconductors
Nature Communications, 2012Co-Authors: Soshi Iimura, Satoru Matsuishi, Hikaru Sato, Taku Hanna, Yoshinori Muraba, Masaki Takata, Hideo HosonoAbstract:The iron pnictides are a class of superconductors that have received widespread interest in recent years. By doping the prototypical material LaFeAsO with hydrogen, this study reveals the existence of a second superconducting dome at higher doping ranges, which arises due to orbital fluctuations.
-
two dome structure in electron Doped iron arsenide superconductors
Nature Communications, 2012Co-Authors: Soshi Iimura, Satoru Matsuishi, Hikaru Sato, Taku Hanna, Yoshinori Muraba, Masaki Takata, Sung Wng Kim, Jungeun Kim, Hideo HosonoAbstract:Iron arsenide superconductors based on the material LaFeAsO(1-x)F(x) are characterized by a two-dimensional Fermi surface (FS) consisting of hole and electron pockets yielding structural and antiferromagnetic transitions at x=0. Electron doping by substituting O(2-) with F(-) suppresses these transitions and gives rise to superconductivity with a maximum T(c) of 26 K at x=0.1. However, the over-Doped region cannot be accessed due to the poor solubility of F(-) above x=0.2. Here we overcome this problem by doping LaFeAsO with hydrogen. We report the phase diagram of LaFeAsO(1-x)H(x) (x<0.53) and, in addition to the conventional superconducting dome seen in LaFeAsO(1-x)F(x), we find a second dome in the range 0.21
Abhijit Chakrabarti - One of the best experts on this subject based on the ideXlab platform.
-
Effects of GM1 on brain spectrin-aminophospholipid interactions.
Biochimica et Biophysica Acta, 2018Co-Authors: Sauvik Sarkar, Dipayan Bose, Rajendra P. Giri, Mrinmay K. Mukhopadhyay, Abhijit ChakrabartiAbstract:Abstract Spectrin, a major component of the membrane skeletal meshwork of metazoan cells, is implicated to associate with membrane domains and is known to act as a scaffold for stabilization and activation of different signalling modules. We have studied the effect of GM1 (monosialotetrahexosyl ganglioside), a well-known model ganglioside and a signalling moiety, on the interaction of non-erythroid brain spectrin with both saturated and unsaturated aminophospholipids by spectroscopic methods. We observe that GM1 modulates brain spectrin-aminophospholipid interaction to the greatest degree whereas its effect on erythroid spectrin is not as pronounced. Fluorescence quenching studies show that brain spectrin interacts with DMPC/DMPE-based vesicles with a 10-fold increased affinity in presence of very low amounts of 2% and 5% GM1, and the extent of quenching decreases progressively in presence of increasing amounts of GM1. Interaction of brain spectrin with unsaturated membrane systems of DOPC/Dope weakens in presence GM1. Increase in the mean lifetime of the Trp residues of brain spectrin in presence of GM1 indicates change in the microenvironment of spectrin, without affecting the secondary structure of the protein significantly. Studies on pressure – area isotherm of Langmuir-Blodgett monolayer and Brewster's angle microscopy show that GM1 has an expanding effect on the aminophospholipid monolayers, and ordered regions in DMPC/DMPE mixed monolayers are formed and are stabilized at higher pressure. GM1-induced fluidization of the phospholipid membranes and probable physical contact between bulky sugar head group of GM1 and spectrin, may explain the modulatory role of GM1 on aminophospholipid interactions with nonerythroid brain spectrin.
-
fluorescence study of the effect of cholesterol on spectrin aminophospholipid interactions
European Biophysics Journal, 2015Co-Authors: Madhurima Mitra, Malay Patra, Abhijit ChakrabartiAbstract:The ability of the membrane skeletal protein spectrin to interact with phospholipids, and aminophospholipids in particular, in both natural and model membranes, is well documented. The present study involves phospholipid-induced quenching of tryptophan fluorescence to probe spectrin–membrane interactions in the presence and absence of cholesterol. We performed the experiments on small unilamellar vesicles of phospholipids made of DMPC and DMPC/DMPE and of DOPC and DOPC/Dope with and without cholesterol at two different temperatures, one below at 15 °C and another above, at 50 °C, the main phase transition temperature (T m) of the bulk phospholipid. Results indicate that erythroid and brain spectrin binds DMPC/DMPE membranes by tenfold and 40-fold stronger, respectively, in the presence of 20 % cholesterol, up to which both gel (Lβ) and liquid crystalline (Lα) phases coexists, at 15 °C particularly in DMPC-based membranes containing saturated fatty acyl chains and not in DOPC-based membranes with appreciably lower T m. Time-resolved fluorescence and circular dichroism spectroscopic studies indicated no significant change in the mean lifetime of the tryptophan residues in spectrin and in the secondary structures of the proteins upon binding to the phospholipid SUVs.
Mitsuru Hashida - One of the best experts on this subject based on the ideXlab platform.
-
the role of dioleoylphosphatidylethanolamine Dope in targeted gene delivery with mannosylated cationic liposomes via intravenous route
Journal of Controlled Release, 2005Co-Authors: Yoshiyuki Hattori, Shigeru Kawakami, Fumiyoshi Yamashita, Sachiko Suzuki, Mitsuru HashidaAbstract:We have previously reported that mannosylated cationic liposome consisting with the mannosylated cationic cholesterol derivative Man-C4-Chol (Man) and dioleoylphosphatidylethanolamine (Dope) (Man/Dope) could deliver DNA to the liver by intravenous administration via mannose receptor-mediated endocytosis, however, rapid degradation in lysosomes might be a rate-limiting step in its gene transfection. In this study, we tried to evaluate the role of Dope in in vivo gene transfer by comparing its transfection efficacy with mannosylated liposomes composed of Man and dioleoylphosphatidylcholine (DOPC) (Man/DOPC). In vitro studies showed that the cellular association of both liposome/pCMV-Luc complexes was almost the same, although Man/Dope complex showed about 10-fold higher transfection activity than Man/DOPC complex. After intraportal administration into mice, Man/Dope complex showed higher gene expression than Man/DOPC complex, suggesting that Dope improves intracellular trafficking in target cells under in vivo conditions. An intravenous administration study demonstrated that Man/Dope complex was accumulated in the liver more efficiently and achieved a higher gene expression in the liver than Man/DOPC complex. Thus, we conclude that the property of Dope in mannosylated liposomes contributes to the efficient gene expression in the target site through enhanced distribution to the target site and intracellular sorting in the target cells under in vivo conditions.
-
asialoglycoprotein receptor mediated gene transfer using novel galactosylated cationic liposomes
Biochemical and Biophysical Research Communications, 1998Co-Authors: Shigeru Kawakami, Fumiyoshi Yamashita, Makiya Nishikawa, Yoshinobu Takakura, Mitsuru HashidaAbstract:We synthesized three novel galactosylated cholesterol derivatives, cholesten-5-yloxy-N-(4-((1-imino-c-beta-D-thiogalactosyl+ ++-ethyl)amino) butyl)formamide (Gal-C4-Chol) and its ethyl formamide and hexyl formamide analogues (Gal-C2-Chol, Gal-C6-Chol), to prepare liposomal gene carriers possessing the cationic charge necessary for plasmid DNA binding and galactose residues as a targetable ligand for liver parenchymal cells. Liposome/DNA complexes prepared with these lipids showed low cytotoxicity in human hepatoma HepG2 cells. Gal-C4-Chol/DC-Chol/Dope(3:3:4) liposomes, consisting of 3:3:4 mixtures of Gal-C4-Chol, 3beta[N',N', N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol), and dioleoylphosphatidylethanolamine (Dope), showed higher transfection activity and [32P]DNA uptake than DC-Chol/Dope(6:4) liposomes. The presence of 20 mM galactose significantly inhibited both transfection efficiency and uptake of DNA of Gal-C4-Chol/DC-Chol/Dope(3:3:4) and Gal-C4-Chol/Dope(6:4) liposomes, but not those of DC-Chol/Dope(6:4) liposomes. These results indicate that the liposome/DNA complexes prepared using novel galactosylated cholesterol derivatives are efficiently recognized by asialoglycoprotein receptors and internalized and lead to gene expression. In addition, we found that the galactosylated cholesterol derivative with a longer spacer showed higher transfection activity.
Sung Wng Kim - One of the best experts on this subject based on the ideXlab platform.
-
two dome structure in electron Doped iron arsenide superconductors
Nature Communications, 2012Co-Authors: Soshi Iimura, Satoru Matsuishi, Hikaru Sato, Taku Hanna, Yoshinori Muraba, Masaki Takata, Sung Wng Kim, Jungeun Kim, Hideo HosonoAbstract:Iron arsenide superconductors based on the material LaFeAsO(1-x)F(x) are characterized by a two-dimensional Fermi surface (FS) consisting of hole and electron pockets yielding structural and antiferromagnetic transitions at x=0. Electron doping by substituting O(2-) with F(-) suppresses these transitions and gives rise to superconductivity with a maximum T(c) of 26 K at x=0.1. However, the over-Doped region cannot be accessed due to the poor solubility of F(-) above x=0.2. Here we overcome this problem by doping LaFeAsO with hydrogen. We report the phase diagram of LaFeAsO(1-x)H(x) (x<0.53) and, in addition to the conventional superconducting dome seen in LaFeAsO(1-x)F(x), we find a second dome in the range 0.21