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crystal structure transporter

Alireza Faghaninia, Guodong Yu, Umut Aydemir, Max Wood, Wei Chen, Gian-Marco Rignanese, G Jeffrey Snyder, Geoffroy Hautier, Anubhav Jain
Bournonite (CuPbSbS3) is an earth-abundant mineral with potential thermoelectric applications. This material has a complex crystal structure (space group Pmn21 #31) and has previously been measured to exhibit a very low thermal conductivity (κ < 1 W m(-1) K(-1) at T ≥ 300 K). In this study, we employ high-throughput density functional theory calculations to investigate how the properties of the bournonite crystal structure change with elemental substitutions. Specifically, we compute the stability and electronic properties of 320 structures generated via substitutions {Na-K-Cu-Ag}{Si-Ge-Sn-Pb}{N-P-As-Sb-Bi}{O-S-Se-Te} in the ABCD3 formula...
February 17, 2017: Physical Chemistry Chemical Physics: PCCP
Kazuhiro Kirihara, Masakazu Mukaida, Yoshiki Shimizu
The electrical transport and thermoelectric property of boron carbide nanowires synthesized by a carbothermal method are reported. It is demonstrated that the nanowires achieve a higher Seebeck coefficient and power factor than those of the bulk samples. The conduction mechanism of the nanowires at low temperatures below 300 K is different from that of the sintered-polycrystalline and single-crystal bulk samples. In a temperature range of 200 to 450 K, there is a crossover between electrical conduction by variable-range hopping and phonon-assisted hopping...
February 16, 2017: Nanotechnology
Daniel E Bugaris, Christos D Malliakas, Fei Han, Nicholas P Calta, Mihai Sturza, Matthew Krogstad, Raymond Osborn, Stephan Rosenkranz, Jacob P C Ruff, Giancarlo Trimarchi, Sergey L Bud'ko, Mahalingam Balasubramanian, Duck Young Chung, Mercouri G Kanatzidis
A new polymorph of the RE2Ru3Ge5 (RE = Pr, Sm, Dy) compounds has been grown as single crystals via an indium flux. These compounds crystallize in tetragonal space group P4/mnc with the Sc2Fe3Si5-type structure, having lattice parameters a = 11.020(2) Å and c = 5.853(1) Å for RE = Pr, a = 10.982(2) Å and c = 5.777(1) Å for RE = Sm, and a = 10.927(2) Å and c = 5.697(1) Å for RE = Dy. These materials exhibit a structural transition at low temperature that occurs due to the charge density wave (CDW). Both the high-temperature average crystal structure and the low-temperature incommensurately modulated crystal structure (for Sm2Ru3Ge5 as a representative) have been solved...
February 16, 2017: Journal of the American Chemical Society
Olivier-Mohamad Soueidan, Thomas W Scully, Jatinder Kaur, Rashmi Panigrahi, Alexandr Belovodskiy, Victor Do, Carson D Matier, M Joanne Lemieux, Frank Wuest, Chris Cheeseman, F G West
The specificity characteristics of transporters can be exploited for the development of novel diagnostic therapeutic probes. The facilitated hexose transporter family (GLUTs) has a distinct set of preferences for monosaccharide substrates, and while some are expressed ubiquitously (e.g., GLUT1), others are quite tissue specific (e.g., GLUT5, which is overexpressed in some breast cancer tissues). While these differences have enabled the development of new molecular probes based upon hexose- and tissue-selective uptake, substrate design for compounds targeting these GLUT transporters has been encumbered by a limited understanding of the molecular interactions at play in hexose binding and transport...
February 16, 2017: ACS Chemical Biology
Takashi Tsukamoto, Susumu Yoshizawa, Takashi Kikukawa, Makoto Demura, Yuki Sudo
Several new retinal-based photoreceptor proteins that act as light-driven electrogenic halide ion pumps have recently been discovered. Some of them, called "NTQ" rhodopsins, contain a conserved Asn-Thr-Gln motif in the 3(rd) or C-helix. In this study, we investigated the photochemical characteristics of a NTQ rhodopsin, Nonlabens marinus rhodopsin 3 (NM-R3), which was discovered in the N. marinus S1-08(T) strain, using static and time-resolved spectroscopic techniques. We demonstrate that NM-R3 binds a Cl(-) in the vicinity of the retinal chromophore accompanied by a spectral blue shift from 568 nm in the absence of Cl(-) to 534 nm in the presence of Cl(-)...
February 14, 2017: Journal of Physical Chemistry. B
Michael Küpers, Philipp M Konze, Stefan Maintz, Simon Steinberg, Antonio M Mio, Oana Cojocaru-Mirédin, Min Zhu, Merlin Müller, Martina Luysberg, Joachim Mayer, Matthias Wuttig, Richard Dronskowski
A hexagonal phase in the ternary Ge-Se-Te system with an approximate composition of GeSe0.75 Te0.25 has been known since the 1960s but its structure has remained unknown. We have succeeded in growing single crystals by chemical transport as a prerequisite to solve and refine the Ge4 Se3 Te structure. It consists of layers that are held together by van der Waals type weak chalcogenide-chalcogenide interactions but also display unexpected Ge-Ge contacts, as confirmed by electron microscopy analysis. The nature of the electronic structure of Ge4 Se3 Te was characterized by chemical bonding analysis, in particular by the newly introduced density of energy (DOE) function...
February 14, 2017: Angewandte Chemie
Xing Zhao, Hui-Seon Kim, Ja-Young Seo, Nam-Gyu Park
Thermal stability of CH3NH3PbI3 (MAPbI3)-based perovskite solar cells was investigated for the normal structure including mesoporous TiO2 layer and spiro-MeOTAD and the invert structure with PCBM and NiO. MAPbI3 was found to be intrinsically stable from 85 oC up to 120 oC in the absence of moisture. However, fast degradation was observed for the encapsulated device including spiro-MeOTAD upon thermal stress at 85 oC. Photoluminescence (PL) intensity and time constant for charge separation increased with thermal exposure time, which is indicative of inhibition of charge separation from MAPbI3 into spiro-MeOTAD...
February 10, 2017: ACS Applied Materials & Interfaces
J C Prestigiacomo, A Nath, M S Osofsky, S C Hernández, V D Wheeler, S G Walton, D K Gaskill
Since its discovery, graphene has held great promise as a two-dimensional (2D) metal with massless carriers and, thus, extremely high-mobility that is due to the character of the band structure that results in the so-called Dirac cone for the ideal, perfectly ordered crystal structure. This promise has led to only limited electronic device applications due to the lack of an energy gap which prevents the formation of conventional device geometries. Thus, several schemes for inducing a semiconductor band gap in graphene have been explored...
February 9, 2017: Scientific Reports
R Wu, R Wilton, M Cuff, M Endres, G Babnigg, J N Edirisinghe, C S Henry, A Joachimiak, M Schiffer, And P R Pokkuluri
We report the structural and biochemical characterization of a novel periplasmic ligand-binding protein, Dret_0059, from Desulfohalobium retbaense DSM 5692, an organism isolated from the Salt Lake Retba in Senegal. The structure of the protein consists of a unique combination of a periplasmic solute binding protein (SBP) domain at the N-terminal and a tandem PAS-like sensor domain at the C-terminal region. SBP domains are found ubiquitously and their best known function is in solute transport across membranes...
February 7, 2017: Protein Science: a Publication of the Protein Society
Chad A Brautigam, Ranjit K Deka, Wei Z Liu, Diana R Tomchick, Michael V Norgard
The spirochete Treponema pallidum is the causative agent of syphilis, a sexually transmitted infection of major global importance. Other closely related subspecies of Treponema also are the etiological agents of the endemic treponematoses, such as yaws, pinta, and bejel. The inability of T. pallidum and its close relatives to be cultured in vitro has prompted efforts to characterize T. pallidum's proteins structurally and biophysically, particularly those potentially relevant to treponemal membrane biology, with the goal of possibly revealing the functions of those proteins...
February 7, 2017: Protein Science: a Publication of the Protein Society
Takahide Okuyama, Ryosuke Yamagishi, Jiro Shimada, Masaaki Ikeda, Yayoi Maruoka, Hiroki Kaneko
Oct4 is a master regulator of the induction and maintenance of cellular pluripotency, and has crucial roles in early stages of differentiation. It is the only factor that cannot be substituted by other members of the same protein family to induce pluripotency. However, although Oct4 nuclear transport and delivery to target DNA are critical events for reprogramming to pluripotency, little is known about the molecular mechanism. Oct4 is imported to the nucleus by the classical nuclear transport mechanism, which requires importin α as an adaptor to bind the nuclear localization signal (NLS)...
February 6, 2017: Journal of Biomolecular Structure & Dynamics
André L F Cauduro, Roberto Dos Reis, Gong Chen, Andreas K Schmid, Christophe Méthivier, Horst-Günter Rubahn, Léo Bossard-Giannesini, Hervé Cruguel, Nadine Witkowski, Morten Madsen
The ability to control the interfacial properties in metal-oxide thin films through surface defect engineering is vital to fine-tune their optoelectronic properties and thus their integration in novel optoelectronic devices. This is exemplified in photovoltaic devices based on organic, inorganic or hybrid technologies, where precise control of the charge transport properties through the interfacial layer is highly important for improving device performance. In this work, we study the effects of in situ annealing in nearly stoichiometric MoOx (x ∼ 3...
February 13, 2017: ACS Applied Materials & Interfaces
Qi Yang, Xiaxia Song, Wendou Zhang, Lei Hou, Qibing Gong, Gang Xie, Qing Wei, Sanping Chen, Shengli Gao
Three new energetic complexes, [Pb(bta)(H2O)]n (1), [PbCu(bta)2(H2O)5]·2H2O (2) and PbCu(bta)2 (3) (H2bta = N,N-bis(1H-tetrazole-5-yl)-amine), have been synthesized and characterised. In particular, 3 was readily synthesized by dehydration of 2 at 190 °C. Single crystal X-ray diffraction revealed that 1 has a 3D framework structure and 2 presents a 3D supermolecular architecture. Thermoanalyses demonstrated that the main frames of 1 and 2 have good thermostabilities up to 314 °C for 1 and 231 °C for 2. Non-isothermal kinetic and thermodynamic parameters of exothermic decomposition processes of 1 and 2 were obtained by Kissinger's and Ozawa's methods...
February 6, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Yazan Haddad, Zbyněk Heger, Vojtech Adam
Targeted therapy is a promising approach for treatment of neuroblastoma as evident from the large number of targeting agents employed in clinical practice today. In the absence of known crystal structures, researchers rely on homology modeling to construct template-based theoretical structures for drug design and testing. Here, we discuss three candidate cell surface proteins that are suitable for homology modeling: human norepinephrine transporter (hNET), anaplastic lymphoma kinase (ALK), and neurotrophic tyrosine kinase receptor 2 (NTRK2 or TrkB)...
2017: Frontiers in Molecular Neuroscience
Jian Chen, Zhen Wang, Shiyi Zheng, Chunmu Feng, Jianhui Dai, Zhu'an Xu
A new ternary platinum phosphide CePt3P was synthesized and characterized by means of magnetic, thermodynamic and transport measurements. The compound crystallizes in an antiperovskite tetragonal structure similar to that in the canonical family of platinum-based superconductors APt3P (A = Sr, Ca, La) and closely related to the noncentrosymmetric heavy fermion superconductor CePt3Si. In contrast to all the superconducting counterparts, however, no superconductivity is observed in CePt3P down to 0.5 K...
February 3, 2017: Scientific Reports
Kinlin L Chao, Liudmila Kulakova, Osnat Herzberg
The exact function of human gasdermin-B (GSDMB), which regulates differentiation and growth of epithelial cells, is yet to be elucidated. In human epidermal growth factor receptor 2 (HER2)-positive breast cancer, GSDMB gene amplification and protein overexpression indicate a poor response to HER2-targeted therapy. Genome-wide association studies revealed a correlation between GSDMB SNPs and an increased susceptibility to Crohn's disease, ulcerative colitis, and asthma. The N- and C-terminal domains of all gasdermins possess lipid-binding and regulatory activities, respectively...
February 1, 2017: Proceedings of the National Academy of Sciences of the United States of America
Adiv A Johnson, Karina E Guziewicz, C Justin Lee, Ravi C Kalathur, Jose S Pulido, Lihua Y Marmorstein, Alan D Marmorstein
Mutations in the gene BEST1 are causally associated with as many as five clinically distinct retinal degenerative diseases, which are collectively referred to as the "bestrophinopathies". These five associated diseases are: Best vitelliform macular dystrophy, autosomal recessive bestrophinopathy, adult-onset vitelliform macular dystrophy, autosomal dominant vitreoretinochoroidopathy, and retinitis pigmentosa. The most common of these is Best vitelliform macular dystrophy. Bestrophin 1 (Best1), the protein encoded by the gene BEST1, has been the subject of a great deal of research since it was first identified nearly two decades ago...
January 30, 2017: Progress in Retinal and Eye Research
Ferdinand M Huber, André Hoelz
Eukaryotic ribosome biogenesis requires the nuclear import of ∼80 nascent ribosomal proteins and the elimination of excess amounts by the cellular degradation machinery. Assembly chaperones recognize nascent unassembled ribosomal proteins and transport them together with karyopherins to their nuclear destination. We report the crystal structure of ribosomal protein L4 (RpL4) bound to its dedicated assembly chaperone of L4 (Acl4), revealing extensive interactions sequestering 70 exposed residues of the extended RpL4 loop...
February 2, 2017: Nature Communications
Daniel Rhodes, Daniel A Chenet, Blanka E Janicek, Clara Nyby, Yi Lin, Wencan Jin, Drew Edelberg, Ehren M Mannebach, Nathan Finney, Abhinandan Antony, Theanne Schiros, Tyler Klarr, Alex Mazzoni, Matthew L Chin, Yu-Che Chiu, WenKai Zheng, Qiu Run Zhang, Friederike Ernst, Jerry I Dadap, Xiao Tong, Junzhang Ma, Rui Lou, Shancai Wang, Tian Qian, Hong Ding, Richard M Osgood, Daniel W Paley, Aaron M Lindenberg, Pinshane Y Huang, Abhay N Pasupathy, Madan Dubey, James C Hone, Luis Balicas
MoTe2 is an exfoliable transition metal dichalcogenide (TMD) which crystallizes in three symmetries; the semiconducting trigonal-prismatic 2H- or α-phase, the semimetallic and monoclinic 1T'- or β-phase, and the semimetallic orthorhombic γ structure. The 2H-phase displays a band gap of ∼ 1 eV making it appealing for flexible and transparent optoelectronics. The γ-phase is predicted to possess unique topological properties which might lead to topologically protected non-dissipative transport channels. Recently, it was argued that it is possible to locally induce phase-transformations in TMDs, through chemical doping, local heating, or electric-field to achieve ohmic contacts or to induce useful functionalities such as electronic phase-change memory elements...
February 1, 2017: Nano Letters
Aaron Mailman, Alicea A Leitch, Wenjun Yong, Eden Steven, Stephen M Winter, Robert C M Claridge, Abdeljalil Assoud, John S Tse, Serge Desgreniers, Richard A Secco, Richard T Oakley
Benzoquino-bis-1,2,3-dithiazole 5 is a closed shell, antiaromatic 16π-electron zwitterion with a small HOMO-LUMO gap. Its crystal structure consists of planar ribbon-like molecular arrays packed into offset layers to generate a "brick-wall" motif with strong 2D interlayer electronic interactions. The spread of the valence and conduction bands, coupled with the narrow HOMO-LUMO gap, affords a small band gap semiconductor with σRT = 1 × 10(-3) S cm(-1) and Eact = 0.14 eV for transport within the brick-wall arrays...
January 31, 2017: Journal of the American Chemical Society
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