bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Pyrrolo-, Thienopyrrolo-, Benzothienopyrroloquinolines as well as Triazoloindole Derivatives
Authors: El-Desoky S. I. , Kandeel E. M. , Abd el-Rahmn A. H. , Shmidt R. R.
Published: February 2015

Substituted pyrroloquinoline, thienopyrroloquinoline, benzothieno-pyrroloquinoline and triazoloindole derivatives have been synthesized starting from 6-amino-2,3-diphenylindole. The structures of the newly synthesized compounds and MS data.
On the Metalation of 2,6-Dimethyl-4-tert-butyl-thiophenol
Authors: Kersting Berthold , Steinfeld Gunther
Published: February 2015

Metalation of 2,6-Dimethyl-4-tert-butyl-thiophenol (6) with n-BuLi/TMEDA in THF occurs regioselectively at the benzylic positions to produce lithium 2,6-di(lithiomethyl)-4-tert-butyl-benzenethiolate (7). Treatment of compound 7 with elem ental sulfur followed by iodine-oxidation affords an oxidation product 9a of bis(sulfanylmethyl)- 4-tert-butyl-thiophenol (5).
Solventothermal Synthesis and Structure of the Polymerie Thioarsenates(III) (Et4N)2As6S10 and (Et4N)2As8S13
Authors: Vater Viola , Sheldrick William S.
Published: February 2015

Reaction of (Et4N)Cl with AS2S3 and Na2S in acetonitrile at 110°C affords the polymeric thioarsenate(III) (Et4N)2As6S10 in which the cyclic [As3S6]3- and chainlike [As3S7]5- trinuclear molecular building units are linked together through common sulphur atoms into infinite double chains. In contrast, reaction of the same starting materials at higher temperatures (180°C) in water leads to formation of a markedly denser phase (Et4N)2As8S13, whose thioarsenate(III) 1
∞ [As8S13
2-] anions exhibit a higher condensation grade. These likewise double chains are composed of cyclic [AS3S6]3- and dinuclear [As2Ss]4- units with shared ѱ-AsS3 tetrahedra corners. Analogous treatment of (Et4N)Cl with As2Se3 and Na2Se in acetonitrile (T =110°C) yields (Et4N)[SeAsSe7].
Synthesis and Molecular Structure of a Superbulky Tertiary Phosphine: Bis[2-phenyl-1,2-dicarba-closo-dodecaboran-1-yl(12)]phenylphosphine
Authors: Balema Viktor P. , Blaurock Steffen , Hey-Hawkins Evamarie
Published: February 2015

Bis[2-phenyl-,2-dicarba-closo-dodecaboran-1-yl(12)]phenylphosphine (2) was obtained in 91% yield from phenyldichlorophosphine and two equivalents of 1-lithium-2-phenyl-1 ,2- dicarba-closo-dodecaborane(12) in ether and characterized by spectroscopy (31P, 11B, 1H, 13C NMR; IR) and by X-ray structure determination.
Darstellung, Kristallstruktur, Schwingungsspektren und Normalkoordinatenanalyse von trans-[OsO2(N2H2C2O2)2]2- / Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of trans-[OsO2(N2H2C202)2]2-
Authors: Strueß A. , Preetz W.
Published: February 2015

The treatment of K2[OsO2(OH)4] with oxamide in aqueous solution yields [OsO2(N2H2C2O2)2]2-. The crystal structure of trans-(Ph4P)2[ OsO2(N2H2C2O2)2]·CH2Cl2 (triclinic, space group P1̅, a = 10.447(1), b = 14.102(4), c = 16.962(2) Å, a = 90.037(1), β = 90.633(7), γ = 98.812(2)°, Z = 2) has been determined by single crystal X-ray diffraction analysis. The IR and Raman spectra were measured at room temperature. Based on the molecular parameters of the X-ray determination a normal coordinate analysis has been performed and the vibrations are assigned. The valence force constants are fd(Os=O) = 6.7, fd(Os-N) = 2.4, fd(C-N) = 4.9, fd(C=0) = 11.15 and fd(C-C) = 4.7 mdyn/Å.
Untersuchungen zum thermischen Verhalten der Osmiumoxide / Investigation of the Thermochemical Behaviour of Osmium Oxides
Authors: Oppermann H. , Marklein B.
Published: February 2015

The heterogeneous reactions:

OsO4,s =OsO4,g, 2OsO2,s = Oss + OsO4,g, Oss + 3OsO4,g = 4OsO3,g, OsO2,s + OsO4,g = 2OsO3,g and the homogeneous reaction OsO4,g = OsO3,g + 1/2 O2,g were determined by total pressure measurements. From this and from chemical transport reactions of OsO2 and Os with Osmium tetroxide, the enthalpy of formation of gaseous OsO3 was computed to ΔH°B(OsO3,g,298) = -40,0 ± 3 kcal/mol.
Metal Complexes of Biologically Important Ligands, CVII [1], Formation of Tris(pentamethylcyclopentadienyl-μ-L-prolinato-iridium) Tris(trifluoromethanesulfonate) with Chiral Self Recognition
Authors: Sünkel Karlheinz , Hoffmüller Winfried , Beck Wolfgang
Published: February 2015

The structure of the title complex consists of [Ir3(C5Me5)3(L-prolinate)3]3+ complex cations and CF3SO3
- anions. Each iridium atom is coordinated in a distorted tetrahedral manner by one cyclopentadienyl group, two carboxylate O atoms and the prolinate N atom. The iridium atoms are bridged by the carboxylate groups. Each of the three stereogenic iridium atoms has the same (S) configuration, i. e. the trimerization of the [Ir(C5Me5)(L-prolinate)]+ fragment occurs with chiral self recognition.
Wechselwirkungen in Molekülkristallen, 147 [1, 2]. Isostrukturelle Wirt/Gast-Einschluß-Verbindungen von N,N'-Ditosyl- p-phenylendiamin mit Aceton, Cyclopentanon, Cyclopent-2-en-l-on, 1,3-Dioxolan, Tetrahydrofuran und 2,5-Dihydrofuran / Interactions in Molecular Crystals, 147 [1, 2], Isostructural Host/Guest-Inclusion Compounds of N,N'-Ditosyl-p-phenylenediamine with Acetone, Cyclopentanone, Cyclopent-2-ene-l-one, 1,3-Dioxolane, Tetrahydrofurane, and 2,5-D ihydrofurane
Authors: Bock Hans , Nagel Norbert , Näther Christian
Published: February 2015

Six isostructural inclusion compounds of various ketone and ether guest molecules into the hydrogen-bonded host-matrix of N,N’-ditosyl-p-phenylenediamine are presented. Crystal growth, structure determinations as well as the arrangement within the clathrates formed is reported and discussed in detail. Packing coefficients and especially the volume ratios between the guest-containig channels and the unit cells allow to estimate the size-limit of guest molecules, which can cocrystallize. Additional crystal growth experiments yield information concerning other types of guest molecules, inclusion from solvent mixtures and guest removal as well as guest exchange processes observed for the N,N′-ditosyl-p-phenylenediamine host matrix.
Four Novel N3O4 Donor Macrocycles and their Lanthanide(III) Complexes
Authors: Bértolo Emilia , Bastida Rufina , Blas Andrés de , Fenton David E. , Macías Alejandro , Rodríguez Adolfo , Rodríguez-Blas Teresa , Villar Ana
Published: February 2015

A new series of lanthanide(III) complexes with two novel Schiff-base macrocycles, L1 and L2, containing a N3O4 donor set have been prepared by cyclocondensation of 2,6-bis(2-formylphen-oxymethyl)pyridine and l,2-bis(2-aminophenoxy)ethane or 1,3-bis(2-aminophenoxy)propane, respectively, in the presence of the appropriate metal salt as a template agent. In the absence of the metal salt the macrocycles are not formed. The diamine macrocycles L3 and L4 are also formed by reaction of the corresponding diamine and dicarbonyl precursors followed by an in situ reduction with NaBH4. Their complexation potential towards Ln(III) ions were also investigated.
Reaktionen des donorfreien (CF3)2Cd mit Phosphor(V)halogeniden: Difluorcarben-Einschiebungen und Direktsynthese von (CF3)3PF2 / Reactions of Donor-Free (CF3)2Cd with Phosphorus(V) Halides: Insertion of Difluorocarbene and Direct Synthesis of (CF3)3PF2
Authors: Eujen Reint , Haiges Ralf
Published: February 2015

Difluorocarbene which is quantitatively eliminated from donor-free bis(trifluoromethyl)- cadmium below 0 °C inserts smoothly into the P-F bonds of PF5 to form (CF3)3 PF2 in high yield. Due to the fast conversion of P-Cl bonds into P-F bonds by cadmium fluoride, PCl5 forms (CF3)3PF2 as well, and a direct synthesis of (CF3)3PF2 with ca. 70 % yield starting from CdEt2, CF3I and PCl5 is reported. Whereas no insertion of CF2 into the axial bonds of (CF3)3PF2 has been detected, reaction of (CF3)2Cd with (CF3)3 PCl2 gives the new tetrakis( haloalkyl)fluorophosphoranes (CF)3 (CF2C1)PF, (CF3)3 (CFCl2 )PF, (CF3)2 (CF2Cl)2PF and (CF3)3 (CCl3)PF. The NMR spectra of these and related compounds and of their hydrolysis products (CF3)3(CF3-nCln)PO are reported. The formation of the higher chlorinated phosphoranes is discussed in terms of an isomerization mechanism presumably involving carbene elimination-reinsertion processes.
Metallkomplexe mit biologisch wichtigen Liganden, CIX [1]. Metallorganische Verbindungen von Platin(II), Ruthenium(II), Rhodium (III) und Iridium (III) mit Oxocarbonyl-N-geschützten a-Am inosäuren und L-Methionylglycinat / Metal Complexes with Biologically Important Ligands, CIX [1]. Organometallic Compounds of Platinum(II), Ruthenium(II), Rhodium(III), and Iridium(III) with Oxocarbonyl-N-protected a-Amino Acids and L-Methionylglycinate
Authors: Prem Markus , Polbom Kurt , Beck Wolfgang
Published: February 2015

The reaction of cis-(Ph3P)2PtCl2 with BOC-N-glycine and FMOC-N-alanine gives the carboxylate coordinated complexes cis-(Ph3P)2 Pt(Cl)(O2CCH2NHBOC) (1) and cis- (Ph3 P)2Pt(Cl)(O2CC(H)(Me)NHFMOC (2). Chloride and proton abstraction from 1 affords the N,O-chelate complex (Ph3P)2Pt(O2CCH2NBOC) (3). From the chloro-bridged compounds [Cp*MCl2]2 (M = Rh, Ir), [(p-cymene)RuCl2]2 and BOC-N-L-MetGlyOH (L) the compounds Cp*M(Cl)2L (4, 5) and (p-cymene)Ru(Cl)2L (6 ) with the mono-dentate dipeptide are obtained which in the presence of NaOMe form O,N,S-bis(chelate) complexes 7 - 9 . The X-ray diffraction analysis of the iridium O,N,S chelate complex 8 shows a five membered and a seven membered chelate ring.
Phosphenium-Komplexe, XXIX [1]. [4+2]-Cycloadditionen von Phospheniumkomplexen des Typs Cp(OC)2W = PR2(R = Alkyl, Aryl) mit 2,3-Dimethylbutadien / Phosphenium Complexes, XXIX [1], [4+2]-Cycloaddition of Phosphenium Complexes of the Type Cp(OC)2W=PR2 (R = Alkyl, Aryl) with 2,3-Dimethylbutadiene
Authors: Malisch Wolfgang , Grün Klaus , Fried Alexander , Reich Wolfgang , Schmeußer Martin , Weis Udo , Baky Christa Abd El , Krüger Carl
Published: February 2015

The phosphenium complexes Cp(OC)2W=PR2 [R = Ph, o-Tol, Me, t-Bu, (2a -d)] react with 2,3-dimethyl-1,3-butadiene (3) via [4+2]-cycloaddition to form the phosphametallacyclohexe­ nes Cp(OC)2W-PR2-CH2-CMe=CMe-CH2 (4a -d). The structure of 4a has been determined by X-ray diffraction.
Synthesis of the Stereoisomers of β-Hydroxyhistidine and their Analytical Identification in Hydrolysates of Bacterial Peptides
Authors: Taraz K. , Weber M. , Budzikiewicz H.
Published: February 2015

The synthesis of the four stereoisomers of β-hydroxyhistidine and their analytical identifi­ cation is reported.
Benzylgallium-Verbindungen. Die Kristallstrukturen von [Mg3Br2,4Cl1,6(OEt2)6][Ga(CH2Ph)4]2 · 0,5 Toluol und [(3,5-Me2C6H3CH2)2GaBr]2 / Benzylgallium Compounds. The Crystal Structures of [Mg3Br2,4Cl1,6(OEt2)6][Ga(CH2Ph)4]2 · 0.5 Toluene and [(3,5-Me2C6H3CH2)2GaBr]2
Authors: Kopp Mike R. , Neumüller Bernhard
Published: February 2015

[Mg3Br2.4Cl1.6(OEt2)6][Ga(CH2Ph)4]2 · 0.5 toluene (1) can be obtained by the reaction of one equivalent of GaCl3 with four equivalents of PhCH2MgBr in Et2O. Recrystallization of the crude product from toluene at 60°C gives colorless crystals of 1. Treatment of GaCl3 with two equivalents 3,5-Me2C6H3CH2MgBr in Et2O gives after recrystallization from toluene the diorganogallium bromide [(3,5-Me2C6H3CH2)2GaBr]2 (2). 1 and 2 were characterized by NMR, IR and MS techniques as well as by X-ray structure analyses. 1 consists in the dication [Mg3Br2.4C1.6(OEt2)6]2+, two gallate units [Ga(CH2Ph)4]- and a toluene molecule, disordered around a center of inversion. 2 forms centrosymmetric dimers [(3,5-Me2C6H3CH2)2GaBr]2.
Die Kristallstruktur von [Me3PN(H)PMe3]4l28, einem Polyiodid mit I3--, l82-- und I14
4--Ionen Crystal / Structure of [Me3PN(H)PMe3]4I28, a Polyiodide with I3-, I8
2- , and I 14
4- Ions
Authors: Gröb Thorsten , Weller Frank , Dehnicke Kurt
Published: February 2015

Black-red single crystals of [Me3PN(H)PMe3]4I28 have been prepared by the reaction of [Me3PNPMe3]I with iodine in dichloromethane solution in the presence of Me3SiI and traces of water. The polyiodide crystallizes triclinically in the space group P1̄ with two formula units per unit cell with the lattice dimensions a = 831.2(1), b = 1661.2(3), c = 1739.0(3) pm, α = 87.26(1)°, β = 79.48(1)°, γ = 78.17(1)°. The structure consists of [Me3PN(H)PMe3]2+ ions, linear I3- ions, z-shaped I82- ions, and zig-zag chains of I14
4- ions, the terminal iodine atoms of which form I···H-N hydrogen bridges to the cations.
The First Hydrogen Containing (Polyfluorocycloalken-l-yl)xenon(II) Salts
Authors: Frohn H.-J. , Bardin V. V.
Published: February 2015

(2-H-Hexafluoro-1,4-cyclohexadien-1-yl)xenon(II) and (2-H-octafluorocyclohexen-1-yl)xenon(II) hexafluoroarsenates and tetrafluoroborates were obtained together with their perfluorinated analogues on reacting the corresponding (2,3,4,5-tetrafluorophenyl)xenon(II) salts with XeF2 in anhydrous HF (aHF). The fluorinated (cyclohexen-1-yl)xenon(II) cations react with bromide and iodide anions in MeCN and aHF under alkenylation of the halide anions.
Tetrakis(sulfurdiimido)silane, -germane and -stannane
Authors: Herberhold Max , Gerstmann Silke , Wrackmeyer Bernd
Published: February 2015

Two tetrakis(sulfurdiimido)silanes [Si(NSNR)4 (R = tBu 1a, SiMe3 1b)], two germanes [Ge(NSNR)4 (R = tBu 2a, SiMe3 2b)] and one stannane [Sn(NSNtBu)4Sn 3a] were prepared and characterised by 1H, 13C, 15N, 29Si and 119Sn NMR spectroscopy in solution, and 3a was also studied in the solid state by 119Sn CP/MAS NMR. Whereas 1a,b and 2a,b are monomeric in solution, the 119Sn NMR data suggest that 3a is associated both in solution and in the solid state, and that the tin atoms are hexa-coordinated. The attempted stepwise synthesis of 1a by using one, two, three or four equivalents of K[(NSN)tBu] led to mixtures of 1a with Cl3Si(NSNtBu) 4a, Cl2Si(NSNtBu)2 5a, and ClSi(NSNtBu)3 6a. Only one sulfurdiimido ligand of the silane 1a reacted with hexachlorodisilane by oxidative addition and cleavage of the Si-Si bond to give the new heterobicyclic derivative 7a which is held together by two different coordinative N-Si bonds.
Synthese und Charakterisierung von kronenetherstabilisierten Platin(IV)- Komplexen mit Aminosäureliganden / Synthesis and Characterization of Amino Acid Complexes of Platinum(IV) Stabilized by Crown Ethers
Authors: Steinborn Dirk , Gravenhorst Olaf , Junicke Henrik , Heinemann Frank W.
Published: February 2015

Crown ether complexed pentachloro(aqua)platinic acid, (H3O)[PtCl5(H2O)]·2(18-cr-6)·6H2O (1) reacts with glycine, L-alanine, and DL-2-aminobutyric acid to give cis-[PtCl4(O-glyH)(H2O)]·(18-cr-6)·H2O (4a)1 and cis-[PtCl4(O-amacH)(H2O)]·(18-cr-6) (amacH = alaH 4b, abuH 4c), respectively, as well as (amacH2)2[PtCl6]·2(18-cr-6) (amacH = glyH 5a, alaH 5b, abuH 5c). The crown ether complexed hexachloroplatinic acid, (H3O) 2[PtCl6]·2(18-cr-6) (2), reacts with glycine to afford (glyH2)[PtCl4(N,O-gly)]·2(18-cr-6)·1.25H2O (6).

The structures of 4b and 6 were determined by X-ray diffraction. The alanine ligand in 4b is a zwitterion that is coordinated to platinum by one oxygen atom of the carboxylate group only. The other oxygen atom is engaged in a strong hydrogen bond to the ds-coordinated aqua ligand. The glycinato ligand in 6 is N, O-coordinated at platinum forming an anion [PtCl4(N,O-gly)]- . The other oxygen atom of the carboxylate group is involved in a strong hydrogen bridge to the cation (glyH2)+. In both complexes hydrogen bridges are formed between the -N+H3 and -NH2 groups of the amino acid ligands and the oxygen atoms of the crown ether molecules.
Onio-assistierte SN2-Reaktionen: Allgemeiner Zugang zu symmetrischen und unsymmetrischen geminal bisoniosubstituierten Methanderivaten / Onio-Assisted SN2-Reactions: General Access to Symmetrical and Unsymmetrical Geminally Bisonio Substituted Methane Derivatives
Authors: Weiss Robert , Handke Matthias , Reichel Silvia , Hampel Frank
Published: February 2015

The arsonium salt [Ph3As-CH2-OTf]+ OTf- 11a contains a 1,1-biselectrophilic Csp3 center which permits to synthesize a wide range of symmetrical and unsymmetrical geminally bisonio-substituted methane derivatives. With neutral nucleophiles INu under mild condi- tions a series of 1.1-bisonium salts [Ph3As-CH2-Nu]2+ 2OTf- 12-23 is obtained in good yields. Under more stringent conditions the triphenylarsonio function in these salts can also be mobilized as a nucleofuge in a subsequent SN-reaction with a second nucleophile | Nu’, yielding a series of novel unsymmetrical 1,1-bisonium salts [Nu-CH2-Nu’]2+ 2OTf- 24-27. Structures 18, 23 and 26b were confirmed by X-ray analysis. For certain nucleophiles a discrete stepwise substitution of both nucleofuges in 11a cannot be realized and the corresponding symmetrical 1,1-bisonium salts (e.g. 28 and 30-32) are obtained directly. The experimental material can be rationalized on the basis of a simple MO model. The conclusion is that stabilization of a hypervalent SN2 transition state by an equatorial oniosubstituent parallels the stability of the underlying ylids. This is corroborated by model calculations. The geminal bisonium salts reported are potential precursors to mono- and 1,1-bisylids and, in special cases, to functional nucleophilic carbenes.
Anodic Methoxylation of Isatin
Authors: Niedźwiecka-Kornaś Anna , Bojarska Elżbieta , Kamiński Jarosław , Kazimierczuk Zygmunt
Published: February 2015

Anodic metoxylation of isatin was investigated. The product formed contained a unique 3a.7a-dihydroindole ring system. 3a,7a-Dihydro-(Z)-3a,7a-dimetoxyisatin was isolated and characterized with a variety of spectroscopic methods.
Fe[B2P2O7(OH)5]: Ein neues Boro-phosphat mit unverzweigten Vierer-Einfach Tetraederketten / Fe[B2P2O7(OH)5]: A New Borophosphate Containing Non-Branched Tetrahedral Vierer-Einfach Chains
Authors: Boy Insan , Hauf Cornelia , Kniep Rüdiger
Published: February 2015

Single crystals of Fe[B2P2O7(OH)5] were grown under hydrothermal conditions at 170 °C. The crystal structure (monoclinic, C 2/c (Nr. 15), a = 1774.7(5), b = 672.0(2), c = 705.9(2) pm, β = 109.01(2)°, Z = 4, Dx= 2.808 g/cm3) contains vierereinfach tetrahedral chains 1
∞[B2P2O7(OH)5]3-, which are formed by alternating borate and phosphate groups connected via common corners: 1
∞[BO2/2(OH)(OH0.5)-PO2/2O(OH)-BO2/2(OH)-(OH0.5)-PO2/2O(OH)]. Fe3+ is in an octahedral coordination (Fe(O)2(OH)4).
Polysulfonylamine, CIII [1] Ein Hydroxylamin mit bemerkenswert kurzer O-N-B Bindung: Kristall- und Molekülstruktur von MeO-N(SO2Me)2 / Polysulfonylamines, C III [1] A Hydroxylamine with a Remarkably Short O-N Bond: Crystal and Molecular Structure of MeO-N(SO2Me)2
Authors: Näveke Martina , Blaschette Armand , Jones Peter G.
Published: February 2015

The crystal structure of the known title compound was determined by low-temperature X-ray diffraction (orthorhombic, space group Pbcn, Z = 4). The molecule displays an unusually short O-N bond, a relatively long C-O bond and a moderately pyramidal O-NS2 skeleton (O-N 133.1, C-O 148.5 pm, sum of bond angles at N: 347.4°).
Modeling of Grout Propagation in Transparent Replica of Rock Fractures
Authors: Sui Wanghua , Qu Hao , Gao Yue
Published: February 2015

This paper presents an experimental investigation on the injection of chemicals into rock fractures by using a transparent replica to visualize grout propagation. The fractured rock mass is simulated by using fused silica blocks, fused silica grains and mineral oils. Fused silica blocks in a cubic form are used to form rock mass and the fused silica grains are used to fill the space between these blocks to simulate fractures with a certain aperture. In addition, a mixed mineral oil that has the same refractive index as that of the fused silica blocks and grains is used to simulate fluid and groundwater. The experimental setup consists of a Plexiglas container, loading frame, grout injection system, and three black and white charge-coupled device (CCD) cameras. A modified urea-formaldehyde resin and an acid solution are mixed together as the grout. The point source of the grouting is simulated by using an injection needle inserted into the model. As the silica blocks are impermeable, the grout instead propagates into the fractures that are filled with silica sand. Propagation images during the grouting are captured by using the CCD cameras. Digital image processing is then applied to analyze the grayscale pictures to detect the edge of the grout front and calculate the grout penetration length at different times. The shape of the boundary of the grout–groundwater interface is found to be spherical when the fractures are filled with porous transparent materials. The results indicate that the flow velocity calculated by using a modified cubic law is in good agreement with the measured penetration length in the images. The results also verify the possibility of the use of a transparent replica to visualize grout propagation inside a fractured rock mass so as to understand grout propagation during grouting.
Effect of Bushing Miniaturization on the Static Friction Coefficient
Authors: Olvera-Tapia Omar , Kussul Ernst , Rodríguez-Lelis José M. , Baidyk Tatiana , Sanchez José
Published: February 2015

As machines become smaller, friction plays an increasingly important role in their performance. Although friction is a well-studied phenomenon, few studies have been performed on bushings and shafts with loads of a few tens of mN and dimensions of a few mm. In this work, the static friction coefficient is investigated for a miniature steel shaft rotating in bronze SAE 40 bushings. A new approach is presented to measure the static friction coefficient of a miniature bushing. The coefficient was evaluated without lubrication. It shows a linear dependence at loads higher than 152 mN and a nonlinear dependence at loads smaller than 152 mN.
Memory Retrieval Requires Ongoing Protein Synthesis and NMDA Receptor Activity-Mediated AMPA Receptor Trafficking
Authors: Lopez Joëlle , Gamache Karine , Schneider Rilla , Nader Karim
Published: February 2015

Whereas consolidation and reconsolidation are considered dynamic processes requiring protein synthesis, memory retrieval has long been considered a passive readout of previously established plasticity. However, previous findings suggest that memory retrieval may be more dynamic than previously thought. This study therefore aimed at investigating the molecular mechanisms underlying memory retrieval in the rat. Infusion of protein synthesis inhibitors (rapamycin or anisomycin) in the amygdala 10 min before memory retrieval transiently impaired auditory fear memory expression, suggesting ongoing protein synthesis is required to enable memory retrieval. We then investigated the role of protein synthesis in NMDA receptor activity-mediated AMPA receptor trafficking. Coinfusion of an NMDA receptor antagonist (ifenprodil) or infusion of an AMPA receptor endocytosis inhibitor (GluA23Y) before rapamycin prevented this memory impairment. Furthermore, rapamycin transiently decreased GluA1 levels at the postsynaptic density (PSD), but did not affect extrasynaptic sites. This effect at the PSD was prevented by an infusion of GluA23Ybefore rapamycin. Together, these data show that ongoing protein synthesis is required before memory retrieval is engaged, and suggest that this protein synthesis may be involved in the NMDAR activity-mediated trafficking of AMPA receptors that takes place during memory retrieval.
G-Protein-Coupled Estrogen Receptor 1 Is Anatomically Positioned to Modulate Synaptic Plasticity in the Mouse Hippocampus
Authors: Waters Elizabeth M. , Thompson Louisa I. , Patel Parth , Gonzales Andreina D. , Ye Hector (Zhiyu) , Filardo Edward J. , Clegg Deborah J. , Gorecka Jolanta , Akama Keith T. , McEwen Bruce S. , Milner Teresa A.
Published: February 2015

Both estrous cycle and sex affect the numbers and types of neuronal and glial profiles containing the classical estrogen receptors α and β, and synaptic levels in the rodent dorsal hippocampus. Here, we examined whether the membrane estrogen receptor, G-protein-coupled estrogen receptor 1 (GPER1), is anatomically positioned in the dorsal hippocampus of mice to regulate synaptic plasticity. By light microscopy, GPER1-immunoreactivity (IR) was most noticeable in the pyramidal cell layer and interspersed interneurons, especially those in the hilus of the dentate gyrus. Diffuse GPER1-IR was found in all lamina but was most dense in stratum lucidum of CA3. Ultrastructural analysis revealed discrete extranuclear GPER1-IR affiliated with the plasma membrane and endoplasmic reticulum of neuronal perikarya and dendritic shafts, synaptic specializations in dendritic spines, and clusters of vesicles in axon terminals. Moreover, GPER1-IR was found in unmyelinated axons and glial profiles. Overall, the types and amounts of GPER1-labeled profiles were similar between males and females; however, in females elevated estrogen levels generally increased axonal labeling. Some estradiol-induced changes observed in previous studies were replicated by the GPER agonist G1: G1 increased PSD95-IR in strata oriens, lucidum, and radiatum of CA3 in ovariectomized mice 6 h after administration. In contrast, estradiol but not G1 increased Akt phosphorylation levels. Instead, GPER1 actions in the synapse may be due to interactions with synaptic scaffolding proteins, such as SAP97. These results suggest that although estrogen's actions via GPER1 may converge on the same synaptic elements, different pathways are used to achieve these actions.
Characteristic Patterns of Dendritic Remodeling in Early-Stage Glaucoma: Evidence from Genetically Identified Retinal Ganglion Cell Types
Authors: El-Danaf Rana N. , Huberman Andrew D.
Published: February 2015

Retinal ganglion cell (RGC) loss is a hallmark of glaucoma and the second leading cause of blindness worldwide. The type and timing of cellular changes leading to RGC loss in glaucoma remain incompletely understood, including whether specific RGC subtypes are preferentially impacted at early stages of this disease. Here we applied the microbead occlusion model of glaucoma to different transgenic mouse lines, each expressing green fluorescent protein in 1–2 specific RGC subtypes. Targeted filling, reconstruction, and subsequent comparison of the genetically identified RGCs in control and bead-injected eyes revealed that some subtypes undergo significant dendritic rearrangements as early as 7 d following induction of elevated intraocular pressure (IOP). By comparing specific On-type, On-Off-type and Off-type RGCs, we found that RGCs that target the majority of their dendritic arbors to the scleral half or “Off” sublamina of the inner plexiform layer (IPL) undergo the greatest changes, whereas RGCs with the majority of their dendrites in the On sublamina did not alter their structure at this time point. Moreover, M1 intrinsically photosensitive RGCs, which functionally are On RGCs but structurally stratify their dendrites in the Off sublamina of the IPL, also underwent significant changes in dendritic structure 1 week after elevated IOP. Thus, our findings reveal that certain RGC subtypes manifest significant changes in dendritic structure after very brief exposure to elevated IOP. The observation that RGCs stratifying most of their dendrites in the Off sublamina are first to alter their structure may inform the development of new strategies to detect, monitor, and treat glaucoma in humans.
Reversal Learning and Dopamine: A Bayesian Perspective
Authors: Costa Vincent D. , Tran Valery L. , Turchi Janita , Averbeck Bruno B.
Published: February 2015

Reversal learning has been studied as the process of learning to inhibit previously rewarded actions. Deficits in reversal learning have been seen after manipulations of dopamine and lesions of the orbitofrontal cortex. However, reversal learning is often studied in animals that have limited experience with reversals. As such, the animals are learning that reversals occur during data collection. We have examined a task regime in which monkeys have extensive experience with reversals and stable behavioral performance on a probabilistic two-arm bandit reversal learning task. We developed a Bayesian analysis approach to examine the effects of manipulations of dopamine on reversal performance in this regime. We find that the analysis can clarify the strategy of the animal. Specifically, at reversal, the monkeys switch quickly from choosing one stimulus to choosing the other, as opposed to gradually transitioning, which might be expected if they were using a naive reinforcement learning (RL) update of value. Furthermore, we found that administration of haloperidol affects the way the animals integrate prior knowledge into their choice behavior. Animals had a stronger prior on where reversals would occur on haloperidol than on levodopa (l-DOPA) or placebo. This strong prior was appropriate, because the animals had extensive experience with reversals occurring in the middle of the block. Overall, we find that Bayesian dissection of the behavior clarifies the strategy of the animals and reveals an effect of haloperidol on integration of prior information with evidence in favor of a choice reversal.
Trip6 Promotes Dendritic Morphogenesis through Dephosphorylated GRIP1-Dependent Myosin VI and F-Actin Organization
Authors: Lv Kaosheng , Chen Liang , Li Yuanjun , Li Zenglong , Zheng Pengli , Liu Yingying , Chen Jianguo , Teng Junlin
Published: February 2015

Thyroid receptor-interacting protein 6 (Trip6), a multifunctional protein belonging to the zyxin family of LIM proteins, is involved in various physiological and pathological processes, including cell migration and tumorigenesis. However, the role of Trip6 in neurons remains unknown. Here, we show that Trip6 is expressed in mouse hippocampal neurons and promotes dendritic morphogenesis. Through interaction with the glutamate receptor-interacting protein 1 (GRIP1) and myosin VI, Trip6 is crucial for the total dendritic length and the number of primary dendrites in cultured hippocampal neurons. Trip6 depletion reduces F-actin content and impairs dendritic morphology, and this phenocopies GRIP1 or myosin VI knockdown. Furthermore, phosphorylation of GRIP1956Tby AKT1 inhibits the interaction between GRIP1 and myosin VI, but facilitates GRIP1 binding to 14-3-3 protein, which is required for regulating F-actin organization and dendritic morphogenesis. Thus, the Trip6–GRIP1–myosin VI interaction and its regulation on F-actin network play a significant role in dendritic morphogenesis.
Circadian Modulation of Dopamine Levels and Dopaminergic Neuron Development Contributes to Attention Deficiency and Hyperactive Behavior
Authors: Huang Jian , Zhong Zhaomin , Wang Mingyong , Chen Xifeng , Tan Yicheng , Zhang Shuqing , He Wei , He Xiong , Huang Guodong , Lu Haiping , Wu Ping , Che Yi , Yan Yi-Lin , Postlethwait John H. , Chen Wenbiao , Wang Han
Published: February 2015

Attention-deficit/hyperactivity disorder (ADHD) is one of the most prevalent psychiatric disorders in children and adults. While ADHD patients often display circadian abnormalities, the underlying mechanisms are unclear. Here we found that the zebrafish mutant for the circadian geneperiod1b(per1b) displays hyperactive, impulsive-like, and attention deficit-like behaviors and low levels of dopamine, reminiscent of human ADHD patients. We found that the circadian clock directly regulates dopamine-related genesmonoamine oxidaseanddopamineβhydroxylase, and acts via genes important for the development or maintenance of dopaminergic neurons to regulate their number and organization in the ventral diencephalic posterior tuberculum. We then found thatPer1knock-out mice also display ADHD-like symptoms and reduced levels of dopamine, thereby showing highly conserved roles of the circadian clock in ADHD. Our studies demonstrate that disruption of a circadian clock gene elicits ADHD-like syndrome. The circadian model for attention deficiency and hyperactive behavior sheds light on ADHD pathogenesis and opens avenues for exploring novel targets for diagnosis and therapy for this common psychiatric disorder.
Basal Ganglia Outputs Map Instantaneous Position Coordinates during Behavior
Authors: Barter Joseph W. , Li Suellen , Sukharnikova Tatyana , Rossi Mark A. , Bartholomew Ryan A. , Yin Henry H.
Published: February 2015

The basal ganglia (BG) are implicated in many movement disorders, yet how they contribute to movement remains unclear. Using wirelessin vivorecording, we measured BG output from the substantia nigra pars reticulata (SNr) in mice while monitoring their movements with video tracking. The firing rate of most nigral neurons reflected Cartesian coordinates (eitherx- ory-coordinates) of the animal's head position during movement. The firing rates of SNr neurons are either positively or negatively correlated with the coordinates. Using an egocentric reference frame, four types of neurons can be classified: each type increases firing during movement in a particular direction (left, right, up, down), and decreases firing during movement in the opposite direction. Given the high correlation between the firing rate and thexandycomponents of the position vector, the movement trajectory can be reconstructed from neural activity. Our results therefore demonstrate a quantitative and continuous relationship between BG output and behavior. Thus, a steady BG output signal from the SNr (i.e., constant firing rate) is associated with the lack of overt movement, when a stable posture is maintained by structures downstream of the BG. Any change in SNr firing rate is associated with a change in position (i.e., movement). We hypothesize that the SNr output quantitatively determines the direction, velocity, and amplitude of voluntary movements. By changing the reference signals to downstream position control systems, the BG can produce transitions in body configurations and initiate actions.
Modulation of Microglial Process Convergence Toward Neuronal Dendrites by Extracellular Calcium
Authors: Eyo Ukpong B. , Gu Nan , De Srijisnu , Dong Hailong , Richardson Jason R. , Wu Long-Jun
Published: February 2015

Extracellular calcium concentrations in the brain fluctuate during neuronal activities and may affect the behavior of brain cells. Microglia are highly dynamic immune cells of the brain. However, the effects of extracellular calcium concentrations on microglial dynamics have not been investigated. Here, we addressed this question in mouse brain slices andin vivousing two-photon microscopy. We serendipitously found that extracellular calcium reduction induced microglial processes to converge at distinct sites, a phenomenon we termed microglial process convergence (MPCs). Our studies revealed that MPCs target neuronal dendrites independent of neuronal action potential firing and is mediated by ATP release and microglial P2Y12 receptors. These results indicate that microglia monitor and interact with neurons during conditions of cerebral calcium reduction in the normal and diseased brain.
Behavioral Relevance Helps Untangle Natural Vocal Categories in a Specific Subset of Core Auditory Cortical Pyramidal Neurons
Authors: Shepard Kathryn N. , Lin Frank G. , Zhao Charles L. , Chong Kelly K. , Liu Robert C.
Published: February 2015

Sound categorization is essential for auditory behaviors like acoustic communication, but its genesis within the auditory pathway is not well understood—especially for learned natural categories like vocalizations, which often share overlapping acoustic features that must be distinguished (e.g., speech). We use electrophysiological mapping and single-unit recordings in mice to investigate how representations of natural vocal categories within core auditory cortex are modulated when one category acquires enhanced behavioral relevance. Taking advantage of a maternal mouse model of acoustic communication, we found no long-term auditory cortical map expansion to represent a behaviorally relevant pup vocalization category—contrary to expectations from the cortical plasticity literature on conditioning with pure tones. Instead, we observed plasticity that improved the separation between acoustically similar pup and adult vocalization categories among a physiologically defined subset of late-onset, putative pyramidal neurons, but not among putative interneurons. Additionally, a larger proportion of these putative pyramidal neurons in maternal animals compared with nonmaternal animals responded to the individual pup call exemplars having combinations of acoustic features most typical of that category. Together, these data suggest that higher-order representations of acoustic categories arise from a subset of core auditory cortical pyramidal neurons that become biased toward the combination of acoustic features statistically predictive of membership to a behaviorally relevant sound category.
Behavioral Oscillation in Priming: Competing Perceptual Predictions Conveyed in Alternating Theta-Band Rhythms
Authors: Huang Yan , Chen Lin , Luo Huan
Published: February 2015

The brain constantly creates perceptual predictions about forthcoming stimuli to guide perception efficiently. Abundant studies have demonstrated that perceptual predictions modulate sensory activities depending on whether the actual inputs are consistent with one particular prediction. In real-life contexts, however, multiple and even conflicting predictions might concurrently exist to be tested, requiring a multiprediction coordination process. It remains largely unknown how multiple hypotheses are conveyed and harmonized to guide moment-by-moment perception. Based on recent findings revealing that multiple locations are sampled alternatively in various phase of attentional rhythms, we hypothesize that this oscillation-based temporal organization mechanism may also underlie the multiprediction coordination process. To address the issue, we used well established priming paradigms in combination with a time-resolved behavioral approach to investigate the fine temporal dynamics of the multiprediction harmonization course in human subjects. We first replicate classical priming effects in slowly developing trends of priming time courses. Second, after removing the typical priming patterns, we reveal a new theta-band (∼4 Hz) oscillatory component in the priming behavioral data regardless of whether the prime was masked. Third, we show that these theta-band priming oscillations triggered by congruent and incongruent primes are in an out-of-phase relationship. These findings suggest that perceptual predictions return to low-sensory areas not continuously but recurrently in a theta-band rhythm (every 200–300 ms) and that multiple predictions are dynamically coordinated in time by being conveyed in different phases of the theta-band oscillations to achieve dissociated but temporally organized neural representations.
Regulation of P21 during diabetes-associated stress of the endoplasmic reticulum
Authors: Mihailidou Chrysovalantou , Chatzistamou Ioulia , Papavassiliou Athanasios G , Kiaris Hippokratis
Published: February 2015

Endoplasmic reticulum (ER) stress plays a major role in the pathogenesis of diabetes by inducing β-cell apoptosis in the islets of Langerhans. In this study, we show that the transcription factor CHOP, which is instrumental for the induction of ER-stress-associated apoptosis and the pancreatic dysfunction in diabetes, regulates the expression of P21 (WAF1), a cell cycle regulator with anti-apoptotic activity that promotes cell survival. Deficiency of P21 sensitizes pancreatic β-cells to glucotoxicity, while in mice genetic ablation of P21 accelerates experimental diet-induced diabetes, results indicative of a protective role for P21 in the development of the disease. Conversely, pharmacological stimulation of P21 expression by nutlin-3a, an inhibitor of P53–MDM2 interaction, restores pancreatic function and facilitates glucose homeostasis. These findings indicate that P21 acts as an inhibitor of ER-stress-associated tissue damage and that stimulation of P21 activity can be beneficial for the management of diabetes and probably of other conditions in which ER-stress-associated death is undesirable.
First records of Landoltia punctata (G.Mey.) Les & D.J.Crawford (Araceae, Lemnoideae) in Santa Catarina, southern Brazil
Authors: Hassemer Gustavo , Mohedano Rodrigo De Almeida , Ferreira João Paulo Ramos , Pott Vali Joana , Trevisan Rafael
Published: February 2015

Landoltia punctata (G.Mey.) Les & D.J. Crawford is a cosmopolite duckweed species of significant economic and technological interest, which in the Americas had its southernmost occurrence recorded in Pontal do Paraná, Paraná state, southern Brazil. This work extends its distribution southwards to Santa Catarina state, representing a range extension of ca. 300 km.
Functionalized Rosette Nanotubes as Novel Electron Donor Materials for Solution-Processed Organic Photovoltaics
Authors: Shuai Liang , Parthasarathy Venkatakrishnan , Cho Jae-Young , Yamazaki Takeshi , Beingessner Rachel L. , Fenniri Hicham
Published: February 2015

Two self-assembling twin guanine-cytosine (G∧C) hybrid molecules featuring porphyrin (TPPO-(G∧C)2) and oligothiophene groups (6T-(G∧C)2) were synthesized. In organic solution, these molecules self-assemble into one-dimensional rosette nanotubes (RNTs) featuring the porphyrin or oligiothiophene groups on the outer surface. Using a combination of imaging and spectroscopic techniques we established the structure of the TPPO-(G∧C)2 and 6T-(G∧C)2 RNTs and compared the HOMO and LUMO energy levels with PC61BM, a well-known electron acceptor material. These studies, in combination with solid-state photoluminescence data of PC61BM-TPPO-(G∧C)2 RNT blended thin films, indicates that these self-assembled nanomaterials have great potential as electron donor materials for solution-processed organic photovoltaics.
Diffusion Wavelet Decomposition for Coarse-Graining of Polymer Chains
Authors: Rinderspacher B. Christopher , Bardhan Jaydeep P. , Ismail Ahmed E.
Published: February 2015

Here we present an alternative approach to coarse graining, based on the multiresolution diffusion-wavelet approach to operator compression, which does not require explicit atomistic-to-coarse-grained mappings. Our diffusion-wavelet method takes as input the topology and sparsity of the molecular bonding structure of a system, and returns as output a hierarchical set of degrees of freedom (DoFs) of system-specific coarse-grained variables. Importantly, the hierarchical compression provides a clear framework for modeling at many model scales (levels), beyond the common two-level CG representation. Our results show that the resulting hierarchy separates localized modes, such as a single C-C vibrational mode, from larger-scale motions, e.g., long-range concerted backbone vibrational modes. Our approach correctly captures small-scale chemical features, such as cellulose ring structures, and alkane side chains or CH2 units, as well as large-scale features of the backbone. In particular, the new method’s finest-scale modes describe DoFs similar to united atom models and other chemically-defined CG models. Modes at coarser levels describe increasingly large connected portions of the target polymers. For polyethylene and polystyrene, spatial coordinates and their associated forces were compressed by up to two orders of magnitude. The compression in forces is of particular interest as this allows larger timesteps as well as reducing the number of DoFs.
Lithium-ion Diffusion in Solid Electrolyte Interface (SEI) Predicted by Phase Field Model
Authors: Guan Pengjian , Liu Lin
Published: February 2015

Solid electrolyte interface (SEI) layer plays a key role in lithium-ion batteries’ degradation research. However, SEI layer microstructure prediction still needs further investigation, especially the lithium-ion diffusion in SEI layer considering its morphology evolution during the growth of SEI. Due to the unique advantage of avoiding explicitly tracking the interfaces with sharp composition gradients, a phase field model is developed to simulate the SEI formation and its morphology evolution that is regarded as a solidification process. Fick’s law and mass balance are applied to investigate lithium-ion concentration distribution and diffusion coefficients of different SEI layers (i.e., compact and porous SEI layers) predicted by the developed phase field model. The simulation results show lithium-ion diffusion coefficients between 298K and 318K are 1.34-1.87(10-16) m2/s and 1.73-2.18(10-12) m2/s for compact SEI and porous SEI layer, respectively. The developed model has great potential to be extended to three dimensional spaces for SEI layer spatial growth investigation and other interfaces with complex morphology evolution.
Role of hydration forces in the properties of electrolyte solutions in the bulk and at interfaces
Authors: Sushko Maria L. , Rosso Kevin M.
Published: February 2015

We present a theoretical approach for modeling electrolyte solutions at interfaces that reaches into the mesoscale while retaining molecular detail. The total Hamiltonian of the system includes interactions arising from density and charge density (ion correlation) fluctuations, direct Coulomb interactions between ions, and at interfaces the image interactions, ion-solid and ion-water dispersion interactions. The model was validated against its ability to reproduce ion activity in 1:1 and 2:1 electrolyte solutions in the 0-2 M concentration range, its ability to capture the ion-specific effect in 1:1 electrolytes at the air-water interface, and solvent structure in a confined environment between hydrophobic surfaces, revealing the central role of ion hydration interactions in specific ion thermodynamic properties in the bulk solutions and at interfaces. The model is readily extensible to treat electrolyte interactions and forces across charged solid-water interfaces.
Effects of Atmospheric Air Plasma Irradiation to Seeds of Radish Sprouts on Chlorophyll and Carotenoids Concentrations in their Leaves
Authors: Sarinont Thapanut , Amano Takaaki , Koga Kazunori , Shiratani Masaharu , Hayashi Nobuya
Published: February 2015

We studied effects of atmospheric air dielectric barrier discharge plasma irradiation to seeds of radish sprouts on chlorophyll and carotenoid concentrations in their leaves. Plasma irradiation increases chlorophyll concentration under some irradiation conditions, whereas the irradiation has little effects on carotenoid concentration. These results show that plasma irradiation to seeds has influence on cell activities in a selective way.
Growth Mechanism of Single-Walled Carbon Nanotubes from Pt Catalysts by Alcohol Catalytic CVD
Authors: Maruyama Takahiro , Kondo Hiroki , Kozawa Akinari , Saida Takahiro , Naritsuka Shigeya , Iijima Sumio
Published: February 2015

Single-walled carbon nanotube (SWCNT) growth from Pt catalysts by an alcohol gas source method, a type of cold-wall chemical vapor deposition (CVD), was investigated. Raman results showed that the diameters of SWCNTs grown from Pt were below 1.2 nm, while transmission electron microscopy (TEM) showed that the diameters of most Pt catalyst particles were above 1.2 nm. This suggests that SWCNT diameters were smaller than Pt catalysts particles. X-ray photoelectron spectroscopy measurements showed that reduction of Pt particles occurred during the SWCNT growth. Based on these experimental data, growth mechanism of SWCNTs was discussed.