bluuebunny/crossref_metadata_2025 huggingface dataset:
Geometric preferences of crosslinked protein‐derived cofactors reveal a high propensity for near‐sequence pairs
Authors: Swain Marla D. , Benson David E.
Published: February 2005

Protein‐derived cofactors that are composed of covalently crosslinked amino acid side chains are of increasing importance in protein science. These crosslinked protein‐derived cofactors (CPDC) are formed either through direct oxidation by metal/O2‐derived intermediates or through outer sphere oxidation by highly oxidizing cofactors. CPDCs that are formed by outer sphere oxidation do not require side‐chain precursors to be coordinated by a metal center, and therefore are more difficult to identify than those formed by direct oxidation. To better understand the propensity for CPDC formation by outer sphere oxidation, the geometrical preferences of CPDCs were examined. The Dezymer algorithm has been used to identify all putative CPDC‐forming mutations in 500 proteins. Geometrically, although chemically unrelated, these CPDCs were found to be similar to disulfide‐bonded cysteine pairs. Additionally, the percentage of near‐sequence pairs (i and i +1 to i and i + 5) increased as the average Cα‐Cα distance between the amino acid pairs increased. This survey also examined the protein databank for proteins with pre‐attack conformations for CPDCs, using non‐bonded contacts reported by Procheck. A total of 323 unique proteins was identified, with 55 being near‐sequence amino acid pairs. The high geometric propensity of near‐sequence amino acid pairs for forming CPDCs is significant due to difficulties associated with detection by structural or mass spectrometric methods. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Overview of the development of Ion Pumps
Authors: Bonmassar Luca
Published: February 2005

The paper reviews the development of ion pumps, their operating principles and describes particular designs. The performance of ion pumps when used for various gases, their range of operation and fields of application are discussed.
Transport of Substances Through Polymeric and Inorganic Layers
Authors: Langowski Horst‐Christian
Published: February 2005

Materialien auf Polymerbasis werden in einer steigenden Zahl von Anwendungen eingesetzt. In vielen Bereichen sind jedoch ihre hohen Durchlässigkeiten für Substanzen wie Gase und Wasserdampf problematisch. Seit langem werden daher zusätzliche Schichten als Permeationsbarriere auf Polymersubstrate aufgetragen, also als Barriere gegen den Stofftransport. Polymere Schichten werden meist aus der Lösung unter Atmosphärendruck aufgetragen, anorganische Schichten durch Vakuumverfahren. Höchste Barriereeigenschaften werden erreicht durch Multischicht‐Systeme aus anorganischen und polymeren Schichten. Der Artikel behandelt die Grundlagen der Stoffpermeation durch solche Schichtsysteme, die Unterschiede beim Stofftransport durch polymere Materialien und dünne anorganische Schichten und die Konsequenzen für die Herstellung von Materialien mit hohen und ultra‐hohen Barriereeigenschaften auf der Basis polymerer Träger.
Struktur‐Eigenschaftsbeziehungen in Perowskitoxiden mit Phasenbreite
Authors: Ullmann Helmut , Vashook Vladimir V. , Al Daroukh Mahmoud , Teske Klaus , Guth Ullrich
Published: February 2005

Der Zusammenhang zwischen Sauerstoff/Metall(O/M)‐Verhältnis und physikalischen Eigenschaften im Bereich der festen Lösung wird anhand von Mischoxiden mit Perowskitstruktur bis 1000 °C und Sauerstoff‐Gleichgewichtsdrücken bis 1 Pa untersucht. Das O/M‐Verhältnis wird mit Hilfe von Festelektrolytzellen bestimmt. Die Oxidionenleitfähigkeit folgt aus Sauerstoff‐Permeationsmessungen. Die elektronische Leitfähigkeit wird nach der Gleichstrom(DC)‐Vierpunktmethode gemessen. Volumen der Einheitszelle, thermische Ausdehnung und Oxidionentransport verändern sich reversibel mit der Konzentration an Sauerstoffleerstellen im Gitter. Die thermische Ausdehnung erhöht sich in Oxiden mit hoher Defektkonzentration um einen isothermen Anteil, der als chemische Ausdehnung bezeichnet werden kann. Durch Messung der elektronischen Leitfähigkeit unter isostöchiometrischen Bedingungen (unverändertes O/M‐Verhältnis) konnte gezeigt werden, dass im gesamten Temperaturbereich ein positiver Temperaturkoeffizient vorherrscht.
Synthesis, Crystal Structure and Electronic Structure of Modulated Pd7‐δSnTe2
Authors: Savilov S. V. , Kuznetsov A. N. , Popovkin B. A. , Khrustalev V. N. , Simon P. , Getzschmann J. , Doert Th. , Ruck M.
Published: February 2005

Pd7‐δSnTe2 was synthesized starting from the elements either by direct reaction at 970 K or by reaction in a tin flux at 1170 K. Depending on the reaction route and starting composition, single crystals of Pd7‐δSnTe2 with slightly different compositions were found: 0.3 ≤ δ ≤ 0.8. The average structure of Pd7‐δSnTe2 (space group I4/mmm, No. 139, a = 4.001(2) Å, c = 20.929(3) Å, Z = 2) is isotypic to those of the respective nickel compounds Ni7‐δSnQ2 (Q = S, Se, Te) and consists of Cu3Au‐like Sn/Pd blocks and NaCl‐like Pd/Te slabs. Additional satellite reflections that occur in the diffraction image of Pd7‐δSnTe2 can be assigned to the modulation vectors q1 = (0, ‐0.4, 0) and q2 = (0.4, 0, 0). The modulated structure was refined in the (3+2) dimensional superspace group I4/mmm(0‐β0, α00)0.ss.mm to an agreement factor of wR2 = 0.070 for 49 parameters and 483 reflections. The origin of the modulation can mainly be attributed to a variation of the occupancy of the Pd sites in the Pn/Te double slabs. Band structure calculations on the stoichiometric phase Pd7SnTe2 suggest metallic behavior for this compound.
Reduced Lanthanum Halides with Ge as Interstitials: La2I2Ge, La2I2Ge2, La3Cl2Ge3, La3Br2Ge3, La3I3Ge, La6I5Ge3 and La7+xI12Ge
Authors: Mattausch Hansjürgen , Zheng Chong , Ryazanov Mikhail , Simon Arndt
Published: February 2005

The title compounds were synthesized from La, LaX3 (X = Cl, Br and I) and Ge under Ar atmosphere at temperatures 860‐1200 °C. Their structures are characterized by Ge‐centered La6 octahedra or trigonal prisms. Ge atoms form planar zigzag [ttctct]∞ (t = trans, c = cis) chains in La3Br2Ge3 and La3Cl2Ge3, graphite‐like hexagon nets in La2I2Ge2, but otherwise are not bonded to each other in La2I2Ge, La2I2Ge2, La3I3Ge, La6I5Ge3 and La7+xI12Ge (x ≈ 0.7). Computational analysis of the electronic structures of these compounds was carried out.
Synthesis and Characterization of Cs2Mo6X14 (X = Br or I) Hexamolybdenum Cluster Halides: Efficient Mo6 Cluster Precursors for Solution Chemistry Syntheses
Authors: Kirakci Kaplan , Cordier Stéphane , Perrin Christiane
Published: February 2005

Cs2Mo6Br14 (1) and Cs2Mo6I14 (2) have been synthesized by solid state chemistry techniques and structurally characterized by single crystal X‐ray diffraction. They crystallize in the P3¯1c space group (Nr. 163) with the following lattice parameters: a = 10.1925(1) Å, c = 15.0690(3) Å, Z = 2 for 1; a = 10.804(5) Å, c = 16.258(5) Å, Z = 2 for 2. These clusters halides, whose structures are related to that of Cs2Mo6Cl8Br6, are built up from discrete [(Mo6Xi8)Xa6]2‐ anionic units (X = Br, I) stacked according to an hexagonal close‐packing arrangement. In the present work, the influence of the halogen on the cesium sites will be evidenced and discussed. Furthermore, a simple high yield preparation method of (TBA)2Mo6Xi8Xa6 will be proposed starting from Cs2Mo6X14.
Synthese, Kristallstruktur und magnetisches Verhalten von [NH3CH3][Gd(Cl2HCCOO)4]
Authors: Rohde Alexander , Urland Werner
Published: February 2005

Einkristalle von [NH3CH3][Gd(Cl2HCCOO)4] wurden durch Reaktion von Gd2O3 mit NH3CH3Cl in einer wässrigen Lösung von Cl2HCCOOH erhalten. Die Verbindung kristallisiert triklin in der Raumgruppe P 1¯ (Nr. 2, Z = 2, a = 811, 5 pm, b = 1228, 4 pm, c = 1228, 9 pm, α = 62, 43°, β = 87, 67°, γ = 84, 48°). Die Gd3+‐Ionen sind durch Carboxylatgruppen zu Ketten verknüpft. Diese kann man sich aus dimeren Einheiten aufgebaut denken, da zwei unterschiedliche Gd3+‐Gd3+‐Abstände auftreten. Das magnetische Verhalten der Verbindung wurde im Temperaturbereich von 1, 77 bis 300 K untersucht. Die magnetischen Daten weisen auf eine intramolekulare ferromagnetische Wechselwirkung in der dimeren Einheit hin (Jintra = +0, 023 cm‐1), die von einer intermolekularen antiferromagnetischen Wechselwirkung überlagert wird (Jinter = ‐0, 007 cm‐1).
Fused Stars and Nano‐Stripes in the Rare Earth Halide La7Sb11Br4
Authors: Zheng Chong , Mattausch Hansjürgen , Li Shoujian
Published: February 2005

The title compound was synthesized from La, LaBr3 and Sb under Ar atmosphere at 950 °C. It crystallizes in the space group Pnma (No. 62) with lattice parameters a = 30.949(6), b = 4.3042(9), c = 19.675(4) Å and Z = 4. Its structure consists of reduced rare earth halide and intermetallic components. These partial structures are the [La8Br8]∞ elongated octagon stars, Sb‐centered [La3Sb]∞ trigonal prismatic columns and stripes of Sb square meshes up to 2.9 nm wide. Computational analysis shows that title compound has one framework electron per formula in the La metal trigonal prisms but otherwise is electron‐deficient in the intermetallic part. Susceptibility measurement revealed temperature‐independent Pauli paramagnetism.
Ba6Pr3I19: Linear [Pr3I16] Trimers with Two Excess Electrons in a Three‐Centre ‐ Two‐Electron Bond
Authors: Gerlitzki Niels , Mudring Anja‐Verena , Meyer Gerd
Published: February 2005

Black single crystals of Ba6Pr3I19 are obtained during the reduction of praseodymium triiodide, PrI3, with barium metal (molar ratio 2:1, maximum temperature 780 °C, tantalum container). The crystal structure (monoclinic, C2/c, Z = 4, a = 1606.2(2), b = 1257.1(2), c = 2263.2(3) pm, β = 95.09(1)°, R1 for 2028 reflections with I0 > 2σ(I0): 0.0747) consists of [Pr3I16] trimers that are built of three square antiprisms sharing two common faces. These trimers share one empty cube thereby forming rows that are arranged in a tetragonal close‐packed fashion and held together by Ba2+ cations; with additional iodide the formula needs to be written as Ba6I3[Pr3I16]. The Pr‐Pr distances within the trimers are only 356.4(2) pm attesting for a rather strong linear (open) three‐centre‐two‐electron bond.
Cis/trans‐Isomerie von [RuCl2(S‐dmso)(tpy)] Komplexen, tpy = Terpyridin‐Ligand
Authors: Knödler Axel , Kaim Wolfgang
Published: February 2005

Die Molekülstruktur der Vorläuferverbindung trans‐[RuCl2(dmso)(terpy)] für [Ru(terpy)]2+‐enthaltende Komplexe wurde für das Trihydrat bestimmt (terpy = 2, 2′:6′, 2″‐Terpyridin). Im Molekül liegen über S koordiniertes DMSO mit der S=O‐Bindung in der Ru(η3‐terpy)‐Ebene sowie axial angeordnete Chloridliganden vor. Elektrochemische Untersuchungen am cis/trans‐Reaktionsproduktgemisch in Dichlormethan zeigen zwei um etwa 0.2 V separierte Oxidationsprozesse für reversible RuII/III‐Übergänge sowie eine irreversible Reduktion. Für das verwandte [RuCl2(dmso)(mtpy)] (mtpy = 4′‐(4‐Methylphenyl)‐2, 2′:6′, 2″‐terpyridin) wurde nur ein Produktisomer isoliert, welches laut Oxidationspotential, 1H‐NMR chemischer Verschiebung und S=O‐Streckschwingungsfrequenz als trans‐Isomer identifiziert werden kann.
Pr4N2S3 und Pr4N2Se3: Zwei nicht‐isotype Praseodym(III)‐Nitridchalkogenide
Authors: Lissner Falk , Schleid Thomas
Published: February 2005

Die nicht‐isotypen Nitridchalkogenide des Praseodyms, Pr4N2S3 und Pr4N2Se3, bilden sich durch Umsetzung von Praseodym‐Metall mit Natriumazid (NaN3), Praseodym‐Trihalogenid (PrX3; X = Cl, Br, I) und dem entsprechenden Chalkogen (Schwefel bzw. Selen) nach sieben Tagen bei 900 °C in evakuierten Kieselglasampullen. Sie kristallisieren beide monoklin in der Raumgruppe C2/c (Pr4N2S3: a = 1788, 57(9), b = 986, 04(5), c = 1266, 49(6) pm, β = 134, 546(7)°, Z = 8; Pr4N2Se3: a = 1311, 76(7), b = 1017, 03(5), c = 650, 42(3) pm, β = 90, 114(6)°, Z = 4). Die Kristallstrukturen beider Verbindungen zeigen jeweils einen schichtartigen Aufbau, bei dem N3‐‐zentrierte (Pr3+)4‐Tetraeder, die über eine gemeinsame Kante verknüpft zunächst Tetraederdoppel bilden, die strukturelle Basis darstellen. Die weitere Verknüpfung dieser [N2Pr6]12+‐Einheiten über die verbleibenden vier freien Ecken zu Schichten gemäß {[N(Pr)(Pr')]3+} führt jedoch zu unterschiedlichen Tetraedernetzen, die für Pr4N2S3 als Schichten mit „Vierer‐ und Achterringen”︁, für Pr4N2Se3 dagegen als Schichten mit „Sechserringen”︁ aufgefaßt werden können. Während in der Kristallstruktur von Pr4N2S3 vier kristallographisch unterschiedliche Pr3+‐Kationen mit Koordinationszahlen von sechs (2×) und sieben (2×) von Seiten der Anionen N3‐ und S2‐ vorkommen, reduziert sich die Anzahl der Kationen im formelgleichen Nitridselenid (Pr4N2Se3) um die Hälfte (auf Pr1 und Pr2), ebenfalls mit den Koordinationszahlen sechs und sieben. Weitere Verknüpfungsmotive von [NM4]9+‐Tetraedern in Kristallstrukturen von Nitridchalkogeniden und Nitridhalogeniden der Selten‐Erd‐Elemente mit der Zusammensetzung N : M = 1 : 2 werden vorgestellt und vergleichend diskutiert.
Kristall‐ und Realstrukturuntersuchungen zur wiederkehrenden Supraleitung in “La5B2C6”
Authors: Simon Arndt , Babizhetskyy V. , Oeckler O. , Mattausch Hj. , Bauer J. , Kremer R. K.
Published: February 2005

Die Phase “La5B2C6” wird in der Literatur als bei 6.9 K supraleitend, aber auch bis zu 2 K als normalleitend beschrieben. Orientierende Versuche zeigen, dass ein Wechsel durch entsprechende thermische Vorbehandlung hervorgerufen werden kann. In umfangreichen präparativen, analytischen und röntgenografischen Untersuchungen werden die Zusammensetzungen für das Auftreten und Verschwinden von Supraleitung in ein und derselben Probe ermittelt. Metallografische Untersuchungen in Verbindung mit Messungen des magnetischen Verhaltens und der spezifischen Wärme belegen eindeutig, dass Supraleitung keine intrinsische Eigenschaft der Phase “La5B2C6” ist, sondern durch Ausscheidungen von B‐haltigem “La2C3‐δ” im C‐reichen und α‐ bzw. β‐La‐Ausscheidungen im metallreichen Gebiet hervorgerufen wird. Die komplette Umhüllung der Boridcarbid‐Kristalle mit La kann trotz dessen geringen Anteils zu vollständiger magnetischer Abschirmung der Proben führen.
[Sm(NH3)9][Sm(Pyr)6], ein komplexes Salz mit zwei homoleptischen Ionen aus der Synthese in flüssigem Ammoniak
Authors: Quitmann Catharina C. , Müller‐Buschbaum Klaus
Published: February 2005

Intensiv gelbe, transparente Kristalle von [Sm(NH3)9][Sm(Pyr)6] (Pyr‐ = Pyrrolat‐Anion, C4H4N‐) wurden aus den Folgereaktionen von Samarium‐Metall mit Pyrrol (C4H4NH) unter solvothermalen Bedingungen bei 185 °C, der anschließenden Umsetzung des Produktgemenges mit flüssigem Ammoniak sowie Tempern des Reaktionsgemenges in überschüssigem Pyrrol bei 150 °C erhalten. [Sm(NH3)9][Sm(Pyr)6] besteht aus zwei homoleptischen, monomeren Baueinheiten und ist sowohl der erste charakterisierte, einkristalline Vertreter eines homoleptischen Selten‐Erd‐Pyrrolats als auch eines homoleptischen Samarium‐Amminkomplexes. Da Samarium bei Normaldruck nicht in flüssigem Ammoniak löslich ist, vermeidet der gewählte Reaktionsweg die sonst nötige Hochdrucksynthese.
Zur Raumchemie des Wasserstoffs in binären und ternären Metallhydriden
Authors: Bronger Welf , Kniep Rüdiger , Kohout Miroslav
Published: February 2005

Die aus den Strukturen binärer und ternärer Metallhydride ermittelten Rauminkremente der Hydridionen nach W. Biltz sowie die auf quantenmechanischer Grundlage berechneten Volumina nach R. F. W. Bader und nach der ELF‐Methode erlauben im gegenseitigen Vergleich Einblicke in die Bindungsverhältnisse. Es ergibt sich eine deutliche Abhängigkeit des Volumens des stark polarisierbaren Hydridions von den Bindungspartnern. In den salzartigen Verbindungen findet man die höchsten Volumenwerte, in den metallischen Systemen die niedrigsten. Beim Einbau von Wasserstoff in metallische Stoffe wie LaH2 oder Pd ist über ELF‐Rechnungen eine Abhängigkeit der Struktur und Zusammensetzung der Einlagerungsverbindung von der Bindungsstruktur des Wirtsgitters zu erkennen.
On the Chemical Bonding in LaPdIn2, LaNiMg2, and LaNiCd2 ‐ Intermetallic Compounds with a Filled Distorted Variant of the CaIn2 Type
Authors: Doğan Ahmet , Johrendt Dirk , Pöttgen Rainer
Published: February 2005

The new intermetallic compound LaNiCd2 was prepared by induction melting of the elements in a sealed tantalum tube in a water‐cooled sample chamber. LaNiCd2 was characterized by X‐ray powder and single crystal data: MgCuAl2 type, Cmcm, a = 427.2(2), b = 994.8(4), c = 816.5(4) pm, wR2 = 0.0429, 302 F2 values, 17 parameters. Refinement of the occupancy parameters revealed small nickel defects resulting in the composition LaNi0.958(6)Cd2 for the investigated crystal. The structure may be described as a nickel filled LaCd2 substructure with distorted CaIn2 related arrangement. The cadmium substructure (304‐324 pm Cd‐Cd) resembles the lonsdaleite type. Together the nickel and cadmium atoms build up a three‐dimensional [NiCd2] network (277 and 278 pm Ni‐Cd) in which the lanthanum atoms fill distorted pentagonal channels. The COHP analysis reveals a Cd‐Cd ICOHP bonding energy comparable with cadmium metal. We show by comparison of Cd‐Cd bonds in LaNiCd2 with those in LaCd2 and hypothetical La□Cd2 that Cd‐Cd bonding is significantly weakened by the formation of the strong Ni‐Cd bonds. Higher electron counts, as in LaPdIn2, lead to stronger Pd‐In bonds at the expense of the In‐In bonding.
Chemischer Transport fester Lösungen. 16 [1] Der Chemische Transport von Mischphasen im System GaAs/GaP
Authors: Rose C. , Locmelis S. , Milke E. , Binnewies M.
Published: February 2005

Mithilfe chemischer Transportreaktionen (Transportmittel Iod, 1000 → 900 °C) konnten im System GaAs/GaP Mischphasen GaAs1‐xPx (x = 0…︁1) durch chemischen Transport erhalten werden. Der Transport erfolgt kongruent. Die Bildung von GaI (g) ist für den Transport verantwortlich.
Synthesis and Crystal Structure of Potassium Osmate(VIII), K2OsO5
Authors: Mogare Kailash M. , Klein Wilhelm , Jansen Martin
Published: February 2005

K2OsO5 was obtained from reaction of osmium powder and KO2 under elevated oxygen pressures. The compound crystallizes in the hexagonal space group P6¯ (a = 10.7730(15), c = 8.1453(16) Å, Z = 6, 1342 independent reflections, R1 = 1.91 %, wR2 = 4.59 %). Osmium is coordinated by five oxygen atoms which are forming a trigonal bipyramid. These polyhedra are arranged in a hexagonal close packing, potassium is occupying the octahedral voids and the centre of two face sharing tetrahedral voids. The compound exhibits a partial disorder of the OsO5 groups, where in each second layer of the hexagonal close packing the bipyramids are observed in two possible orientations. Magnetic measurements show diamagnetic behaviour confirming the presence of osmium in the oxidation state of + 8.
The Co2Al9 Structure Type Revisited
Authors: Boström Magnus , Rosner Helge , Prots Yurii , Burkhardt Ulrich , Grin Yuri
Published: February 2005

The centrosymmetric structure of Co2Al9 (space group P21/c, Pearson symbol mP22), the isotypic structures of Rh2Al9 and Ir2Al9 and the slightly distorted acentric structures of Rh2Ga9 and Ir2Ga9 (space group Pc) were reinvestigated from single crystal X‐ray diffraction data. The structure of Rh2Ga9 represents a new structure type. The difference between the aluminides and the gallides originates in the details of atomic interactions investigated by the electron localization function and band structure calculations.
Production of Ultrafine Single‐Crystal Copper Wires through Electron Beam Irradiation of Cu‐containing Zeolite X
Authors: Anderson Paul A. , Edmondson Michael J. , Edwards Peter P. , Gameson Ian , Meadows P. Jill , Johnson Simon R. , Zhou Wuzong
Published: February 2005

We report the controlled synthesis of bare, single‐crystal copper nanowires, of high aspect ratio, through electron beam irradiation of copper‐containing zeolite X. The precursor material was specially prepared from as‐synthesized sodium zeolite X in a two stage process designed to maximize the number of copper ions bound within the zeolite. A high degree of experimental control over the copper wire length, its original location on the host crystallite and the crystal morphology has been achieved through judicious manipulation of the electron beam. Our results confirm that this promising new fabrication technique is not confined to silver but is applicable to other metals, which have previously been difficult to produce by other routes.
Structural and Magnetic Properties of Mn2GeSe4
Authors: Deiseroth Hans‐Jörg , Aleksandrov Krasimir , Kremer Reinhard K.
Published: February 2005

Mn2GeSe4 is one of the rare ternary transition metal selenides which crystallizes in the olivine structure‐type (space group Pnma no. 62, Z = 4) with the room‐temperature lattice parameters a = 13.350(3) Å, b = 7.765(2) Å, c = 6.307(1) Å. The crystal structure is based on a hexagonal close packing of Se2‐ with Mn2+ ions in octahedral and Ge4+ ions in tetrahedral coordination. Between 350 K and 150 K the magnetic susceptibility of Mn2GeSe4 is characterized by a Curie‐Weiss‐behaviour with an effective moment of 5.90(3) μBohr indicative for Mn2+ ions with a 3d5 configuration (S = 5/2) and a paramagnetic Curie temperature of ‐240(5) K indicating predominant antiferromagnetic coupling between the Mn2+ ions with a significant deviation from linear behaviour of 1/χ towards lower temperatures. At 66 K a sudden drop of 1/χ is observed which we ascribe to the onset of long‐range magnetic ordering.
Synthesis and Crystal Structure of (Sb2Te2)[AlCl4], a Compound Containing a Heteroatomic Polymeric Cation (Sb2Te2+)n
Authors: Beck Johannes , Schlüter Stefan
Published: February 2005

The reaction of tellurium, antimony, antimony trichloride, sodium chloride, and an excess of aluminium trichloride in a closed evacuated glass ampoule yields dark red crystals of (Sb2Te2)[AlCl4]. During the reaction a melt is formed from which needle shaped crystals of the title compound grow on sublimating off the volatile AlCl3 at 130 °C. Energy dispersive X‐ray emission analysis showed the 1:1 ratio of Sb:Te. The crystal structure analysis (triclinic, P1¯, a = 949.30(2), b = 1348.24(3), c = 1804.97(5) pm, α = 78.983(2), β = 88.060(1), γ = 88.444(1)°, V = 2239.65(9)·106 pm3, Z = 8) shows that the structure is built of almost regular tetrahedral [AlCl4]‐ anions and of one‐dimensional polymeric (Sb2Te2+)ncations. The assignment of Sb and Te atoms to the respective atom positions of the cations was performed by an analysis of the occupation factors, a reasonable electron and charge distribution, and by the analysis of the cation‐anion interactions. The unit cell contains two symmetrically independent but almost isostructural cations which form strands made up of four‐membered stacked Sb2Te2 rings. These rings are connected with their neighboured rings alternatingly via two, three, and four covalent bonds. Predominantly Sb‐Te bonds are present, in smaller degree Sb‐Sb bonds, while Te‐Te bonds are not observed. The cationic strands can be interpreted by the Zintl concept in the connectivity of the different atom types and the resulting charges.
Divalent Titanium: The Halides ATiX3 (A = K, Rb, Cs; X = Cl, Br, I)
Authors: Jongen Liesbet , Gloger Thomas , Beekhuizen Jan , Meyer Gerd
Published: February 2005

Within the 3×3 library of ternary alkali halides of titanium(II), ATiX3 (A = K, Rb, Cs; X = Cl, Br, I), five compounds were synthesized by conproportionation reactions. Single crystals were grown and the structures determined by single‐crystal X‐ray techniques. The halides ATiX3 crystallize either with the so‐called hexagonal perovskite type structure (CsNiCl3, 2H), or with the so‐called KNiCl3‐type of structure. This latter type allows two structural degrees of freedom. First, a shift of the colums of face‐sharing [TiCl6] octahedra against each other and, secondly, a rotation of these colums relative to each other. With these degrees of freedom, individual coordination spheres are designed for the alkali‐metal cations A+.
Subcellular localization of iodinated thyroid tubulin
Authors: Hargreaves Alan J. , Lamas Luis , Santisteban Pilar , Avila Jesus
Published: February 2005

Subcellular fractions enriched in mitochondria, plasma membranes, microsomes and Golgi apparatus were obtained from thyroid glands of rats injected with I125. Autoradiography of SDS-polyacrylamide gels revealed the presence of a number of radiolabelled proteins in each membrane fraction. One polypeptide, with the same electrophoretic mobility as brain tubulin, was found in all fractions except the plasma membranes and was immunoprecipitated with commercial anti-tubulin monoclonal antibodies. Hydrolysis of Asp-Pro linkages of I125 labelled tubulin with formic acid indicated that there were iodination sites in both the carboxy terminal one third and the amino terminal two thirds of the molecule. These results, together with the absence of iodinated tubulin from the cytosolic fraction, are consistent with the idea that a population of thyroid membrane tubulin is iodinated at multiple sites either just before or after insertion into intracellular membranes where it may act as an anchorage point for microtubule-membrane interactions.
Amino acid sequence of rabbit ventricular myosin light chain-2: Identity with the slow skeletal muscle isoform
Authors: Collins John H. , Theibert Janet L. , Libera Luciano Dalla
Published: February 2005

Many studies have established a correlation of differences in the activities of various muscle types with differences in the expression of myosin isoforms. In this paper we report the sequence determination of myosin light chain-2 from rabbit slow skeletal (LC2s) and ventricular (LC2v) nmscles. We sequenced tryptic peptides from LC2v which account for all except a few terminal amino acid residues. The major part (87 residues) of the rabbit LC2s sequence, obtained from tryptic and cyanogen bromide (CNBr) peptides, was found to be identical to rabbit LC2v. Our results provide the first sequence information on LC2s from any species, and lend strong support to the hypothesis that LC2s and LC2v are identical. Comparisons of rabbit LC2v and LC2s with rabbit LC2f (from fast skeletal muscle), and also with chicken LC2f and LC2v, show clearly that LC2s and LC2v from mammalian and avian species are more closely related to each other than they are to LC2f isoforms from the same species.
Viroid RNA is accepted as a template for in vitro transcription by DNA-dependent DNA polymerase I and RNA polymerase from Escherichia coli
Authors: Rohde Wolfgang , Rackwitz Hans-Richard , Boege Frank , Sänger Heinz L.
Published: February 2005

The RNA genome of potato spindle tuber viroid (PSTV) is transcribed in vitro into complementary DNA and RNA by DNA-dependent DNA polymerase I and RNA polymerase, respectively, from Escherichia coli. In vitro synthesis of complementary RNA produces distinct transcripts larger than unit length thus reflecting the in vivo mechanism of viroid replication. The influence of varying experimental conditions on the transcription process is studied; actinomycin D is found to drastically reduce complementary RNA synthesis from the PSTV RNA template by RNA polymerase.
A severe and a mild potato spindle tuber viroid isolate differ in three nucleotide exchanges only
Authors: Gross Hans J. , Liebl Ursula , Alberty Heidemarie , Krupp Guido , Domdey Horst , Ramm Karla , Sänger Heinz L.
Published: February 2005

Fingerprint analyses of two potato spindle tuber viroid (PSTV) isolates causing severe and mild symptoms~ respectively, in tomato exhibited defined differences in the RNase T1 and RNase A fingerprints. The complete sequencing of the mild isolate and the comparison of its primary structure with the previously established one of the pathogenic type strain revealed that oligonucleotides CAAAAAAG, CUUUUUCUCUAUCUUACUUG, and AAAAAAGGAC in the ‘severe’ strain are replaced by CAAUAAG, CUUUUUCUCUAUCUUUCUUUG, AAU, and AAGGAC in the 'mild' strain. Thus, three nucleotide exchanges at different sites of the molecule may change a pathogenic viroid to a practically non-pathogenic isolate. The possible correlation between the secondary structure in a defined region of the PSTV molecule and its pathogenicity for tomato is discussed.
A method for sequencing single-stranded cloned DNA in both directions
Authors: Hong G. F.
Published: February 2005

A DNA sequencing method has been developed whereby DNA that has been cloned in a single-stranded bacteriophage vector can be sequenced from both ends. The method involves first making a minus-strand sense template from a single-stranded insert in the vector MJ3mp2 using a flanking primer, and then sequencing the synthesized template using the dideoxynucleotide termination method (Sanger et al., 1977, 1980) with a second primer. Special conditions are described under which the first primer is easily removed after making the templat% and sequencing in the opposite direction can be done in the normal way (Sanger et al., 1980) without separating the double strands. This method renders it possible to read up to twice the amount of sequence data from a long insert and also to check short inserts by producing complementary sequence patterns.
Characterization of the somatostatin-like immunoreactivity extracted from an adrenal medullary tumour
Authors: Corder R. , Sykes J. E. C. , Lowry P. J.
Published: February 2005

Significant amounts of somatostatin-like immunor reactivity (SLI) were detected in the extract of a human catecholamine-secreting adrenal medullary tumour. After salt fractionation and reconstitution the major portion of SLI was purified by gel filtration and two HPLC steps; in all three systems it eluted in the position of somatostatin-14. The purified somatostatin-like peptide inhibited, in a dose-related manner, growth hormone release from stimulated perfused rat anterior pituitary ceils in vitro. Amino acid analysis showed the purified peptide to have an identical composition to somatostatin found in other species.
Evidence for the transcription of physiologically inactive rat-liver nucleolar chromatin by Escherichia coli RNA polymerase
Authors: Yu Fu-Li , Barrett Annabella
Published: February 2005

Rat-liver nucleoli (10–15 pg DNA) were digested with either 0.6 or 3 units of DNase I for various times (up to 1 h). RNA synthesis was then measured in the absence or presence ol 3 units of Escherichia coli RNA polymerase. It was found that the nucleolar chromatin supporting the endogenous engaged RNA polymerase I transcription was compl-etely destroyed in 3 min with either concentration of DNase I. The nucleolar chromatin template transcribed by E. coli RNA polymerase retained 50% of its original capacity even 60 min alter 3 units of DNase I digestion. When hybridization experiments were conducted, it was found that the DNAs derived from both levels of DNase-Idigested nucleoli were incapable of forming hybrids with the labelled nucleolar RNA synthesized by the engaged RNA polymerase I from the untreated nucleoli. Since the engaged RNA polymerase I transcribes only the physiologically active genes of the nucleolar chromatin, and the RNA transcripts represent active gene product, these data suggest that DNase I digestion has completely destroyed the active genes of the nucleolar chromatin, and E. coli RNA polymerase is able to transcribe the inactive nucleolar chromatin template.
Lipolytic and adenyl-cyclase-stimulating activity of Nα-trinitrophenyl glucagon: Comparison with other glucagon derivatives modifed at the amino terminus
Authors: Jean-Baptiste Emile , Rizack Martin A. , Epand Richard M.
Published: February 2005

The trinitrophenyl (TNP) derivative of glucagon has less [ipolytic activity and potency than the carbamyl derivative. The Nα,∊-acetyl derivative has slightly less activity than the TNP derivative. In contrast to liver, where the TNP derivative fails to stimulate adenyi cyciase, all the derivatives stimulate this enzyme in the adipocyte.
Direct evidence for opposite effects of D-glucose and D-glyceraldehyde on cytoplasmic pH of mouse pancreatic β-cells
Authors: Arkhammar Per , Berggren Per-Olof , Rorsman Patrik
Published: February 2005

The effects of D-glucose, D-glyceraldehyde, glibenclamide, D-600, NH4+ and high concentrations of K+ on cytoplasmic pH (pHi) were investigated in dispersed and cultured pancreatic β-cells from ob/ob mice. The cytoplasmic pH was measured with the fluorescent H+-indicator quene 1. The average pHi value in resting β-cells was 6.71. Addition of 20 m M of the physiological stimulus D-glucose increased pHi with 0.05 units. Both glibenclamide and high concentrations of K+ decreased pHi. The latter effects were completely reversed by D-600, supporting the notion that free cytoplasmic Ca2+ can be involved in the regulation of pHi. In contrast to D-glucose, 10m M of D-glyceraldehyde decreased pHi by 0.09 units, an effect persisting even in the presence of D-600. From the present study it is evident that D-glyceraldehyde and D-glucose have opposite effects on pHi in pancreatic β-cells.
DNA cytosine methylation and heat-induced deamination
Authors: Ehrlich Melanie , Norris Kyle F. , Wang Richard Y. , Kuo Kenneth C. , Gehrke Charles W.
Published: February 2005

The heat-induced conversion of 5-methylcytosine (m5C) residues to thymine residues and of cytosine to uracil residues in single-stranded DNA was studied. The calculated rates for deamination at 37°C and pH 7.4 were ∼9.5×10−10 and 2.1×10−10 sec−1, respectively. N4-Methyldeoxycytidine, which is in the DNA of certain thermophilic bacteria, was more heat-resistant than was deoxycytidine and much more than was 5-methyldeoxycytidine. Thermophilic bacteria which contain N4-methylcytosine rather than m5C in their genomes may thereby largely avoid heat-induced mutation due to deamination, which is incurred by the many organisms that contain m5C in their DNA.
Suppression of liver uptake of orally fed liposomes by injection (I.P.) of dextran sulfate 500
Authors: Das Nirmalendu , Basu Mukul Kumar , Das Manoj Kumar
Published: February 2005

125Iodine labelled human immunoglobulin-G encapsulated liposomes were administered orally to rats. Distribution of radioactivity was checked in various tissues and in portal blood. The effect of dextran sulfate (DS 500,000 m. wt., liver blockade agent) injection (i.p.) on the liver uptake of liposomes and on the amount of liposomes appearing in the portal blood from the gastrointestinal tract have been studied. An increased amount of radioactivity was observed in the portal blood and the amount of radioactivity in the liver decreased appreciably after injection of dextran sulfate. In both the cases the action of dextran sulfate started 2 hours after injection and reached maximum at 12 hour, falling slightly at 24 hour.
The adenylate cyclase response to parathyroid hormone in fetal lung fibroblasts is enhanced by cortisol
Authors: Lowe Carolyn , Barling Peter M. , Skinner Stephen J. M.
Published: February 2005

Parathyroid hormone (PTH, <10−8 M) stimulated adenylate cyclase in fibroblasts, but not epithelial cells, isolated from fetal rat lung. In contrast to osteosarcoma cells (UMR 106), the response of fibroblasts to PTH was increased by pretreatment with cortisol (< 10−8-10−7 M).
New Roles of a Neuropeptide Cortistatin in the Immune System and Cancer
Authors: Li Min , Yan Shaoyu , Fisher William E. , Chen Changyi , Yao Qizhi
Published: February 2005

Cortistatin (CST) is a neuropeptide that strongly resembles somatostatin (SS) structurally and functionally. CST binds to all five SS receptors (SSTR1‐SSTR5) with high affinity and exerts its function mainly through SSTRs. Despite many similar functions between these two neuropeptides, they are products of different genes. Recently, some distinct functions and receptor usage of CST have been reported. Some of the interesting functions of CST were not found with SS. Therefore CST could have potential new roles in an ex‐neuronal system that regulates immune responses as well as other cellular functions in the body. In this review, we discuss the new functions of CST in the immune system, cancer pathogenesis, and possible CST‐specific receptors.
Roles of Neuropilins in Neuronal Development, Angiogenesis, and Cancers
Authors: Chen Changyi , Li Min , Chai Hong , Yang Hui , Fisher William E. , Yao Qizhi
Published: February 2005

Neuropilin‐1 (NRP1) and neuropilin‐2 (NRP2) are transmembrane glycoproteins that have been characterized as receptors for both semaphorins for neuronal guidance and vascular endothelial growth factor (VEGF) for angiogenesis. Biologic properties of NRPs have been linked to their unique domain structures. However, molecular interaction among NRPs, VEGF, and VEGF receptors is still not clear. Although several types of cancer cells can express NRPs, the role of NRPs in tumor pathogenesis is largely unknown. Thus, future investigations should include determining the effects and mechanisms of NRPs on proliferation, apoptosis, and migration of neuronal, endothelial, and cancer cells. Study of protein‐protein interaction, signal transduction pathways, and NRP‐mediated gene expression is particularly important to understand NRPs functions, which may have significant clinical applications in the treatment of neurological disorders, cardiovascular diseases, and certain cancers.
Lexicography on an epic scale: Robert Burchfield, 1923–2004
Authors: McARTHUR TOM
Published: February 2005

THE WORLD-RENOWNED Oxford lexicographer Robert William Burchfield is a hero of mine who, to my great good fortune, became first a colleague then a friend, as he also was to ET.
Failures of intercultural communication caused by translating from Chinese into English
Authors: DONG NAITING
Published: February 2005

In recent years, there has been a heated discussion as to the quality of English education in mainland China. The central argument has been that, although children begin to learn English at the age of ten, and continue the study throughout their education, when they communicate with English native speakers they have difficulties both in understanding and in making themselves understood. English native speakers may also have difficulty understanding them, for reasons that include direct translation from Chinese into English, especially as regards everyday Chinese administrative and technical terms. This paper analyses this problem in terms of both vocabulary acquisition and translation.
The American sitcom in a Brazilian setting
Authors: REES DILYS KAREN
Published: February 2005

Sameness and difference across two nations and languages. In order to begin the discussion regarding a sitcom from American television used in a Brazilian classroom, I believe it is necessary to discuss the situation of the world as we know it at the beginning of the 21st century. Using the theories of the Brazilian sociologist Renato Ortiz (1994) as the basis for this discussion, it is possible to differentiate between the terms global and world-systemic (or mundial). In this view, global refers to the economic and technological processes at work in the modern day world, while world-systemic refers to the domain of culture. The category world is linked to the global, but signifies a world-view, a symbolic universe which is specific to the historic moment in which we live.
Poetry from the heart
Authors: YEH AIDEN
Published: February 2005

Task-based classroom work in Taiwan that uses a mix of traditional teaching, multimedia, and online video. In this paper, I discuss how poetry can be used as a topic of discussion and the basis for a task-based project for university students who have had little exposure to American poetry. The use of multimedia and online video as tools in the course of this project is also discussed and attention is likewise given to student feedback on a questionnaire administered online. Students' critical reflections and subjective analyses of their performances and their feelings toward the project reveal positive results, allowing me to conclude that the integration of poetry into language-teaching work, if delivered effectively, can hone students' thinking, reading, listening, writing, speaking and analytical skills. It is not only the amount of hard work that matters, but how far the imagination is stretched.
On some uses of singular collective nouns
Authors: AREMO W. B.
Published: February 2005

This paper draws attention to some uses of the singular collective nouns congress, council, government, management, parliament, and senate in contemporary English. In particular, it demonstrates how in such uses, the singular collective nouns – like members of the main class of proper nouns – have unique reference, occur without any determiner, take singular pronoun substitutes, and as subject in the sentence have singular concord with the verb. It concludes by providing from contemporary English texts some examples illustrating the uses of the six singular collective nouns discussed.
Cysteamine, glutathione and ionomycin treatments improve in vitro fertilization of prepubertal goat oocytes
Authors: Urdaneta Aixa , Jiménez Ana Raquel , Paramio María-Teresa , Izquierdo Dolors
Published: February 2005

The aim of this study was to improve in vitro embryo development of prepubertal goat oocytes by studying the effect of adding cysteamine to in vitro maturation medium, glutathione (GSH) to in vitro fertilization medium and ionomycin to the sperm capacitation medium. In experiment 1, we analysed the effect of 1 mM GSH added to fertilization medium of oocytes matured with 400 μM cysteamine. The control group were oocytes without cysteamine and GSH. In experiment 2, oocytes matured and fertilized in the presence of 400 μM cysteamine and 1 mM GSH, respectively, were inseminated with spermatozoa treated with ionomycin or heparin. In experiment 1, the percentages of total and normal fertilized oocytes were significantly higher for oocytes supplemented with cysteamine and GSH (40.26% and 30.20%, respectively) than for oocytes from the control group (16.66%, and 10.61%, respectively). The percentage of total embryos obtained after 7 days of culture was significantly higher in the group supplemented with cysteamine and GSH (30.62%) than in the control group (8.09%) . In experiment 2, percentages of total and normal fertilized oocytes were significantly higher for the group of spermatozoa capacitated with ionomycin (52.21% and 37.17%, respectively) than with heparin (38.62% and 28.35%, respectively). After 7 days of culture, total embryo rate was significantly higher in the group of sperm capacitated with ionomycin (44.91%) than with heparin (38.69%) . However, the percentage of embryos developed to the blastocyst stage was not affected by any of the treatments studied.
Detection of rare Leydig cell hypoplasia in somatic cell cloned male piglets
Authors: Park Mi-Rung , Cho Seong-Keun , Park Jong-Yi , Lee So-Young , Choi Yun-Jung , Kwon Deug-Nam , Son Woo-Jin , Seo Han-Geuk , Kim Jin-Hoi
Published: February 2005

In this investigation, 22 cloned male piglets were obtained by male fetal fibroblast-cell-derived nuclear transfer. Eighteen of the cloned animals died. The two cell lines did not differ significantly with regard to efficiency of live piglet production. The gross anatomy of the testes of male piglets that died was normal. However, one piglet displayed Leydig cell hypoplasia (LCH). No anatomical defects were detected in the testes of other cloned male piglets. TUNEL analysis of the testis with LCH revealed significant apoptosis in the Leydig cells, while apoptosis was rarely detected in Sertoli cells and spermatogonia. In contrast, testes from the remaining 17 piglets that died appeared normal in size, and their Sertoli and Leydig cell numbers were comparable to those in control piglet testes. Although cloned piglets were derived from fibroblasts obtained from the same fetus, phenotypic instability between cells used for the production of somatic cell cloned piglets suggests that abnormalities in male cloned piglets are caused not by technical problems and/or reprogramming effects, but rather by epigenetically and/or genetically damaged cell-specific effects.
Is there a germ plasm in mouse oocytes?
Authors: Reunov Arkadiy
Published: February 2005

It was found that in the Graafian oocytes of laboratory mice Mus musculus the population of electron-dense bodies contains two patterns of structures. One of these, designated as cortical granules, originated from the Golgi complex and was surrounded by a membrane. The other was discovered as cristae-containing mitochondrial derivatives lacked an outer membrane. It was found that the mitochondrial derivatives underwent progressive condensation and transformed into electron-dense bodies similar to germinal bodies of metazoan animals. Based on examination of Graafian follicle oocytes from 5 female individuals, about 15% of electron-dense bodies were cortical granules. However, about 85% of electron-dense bodies were condensing mitochondrial derivatives transforming into electron-dense bodies.
The effects of chemical enucleation combined with whole cell intracytoplasmic injection on panda–rabbit interspecies nuclear transfer
Authors: Jiang Man-Xi , Yang Cai-Xia , Zhang Li-Sheng , Zheng Yue-Liang , Liu Shu-Zhen , Sun Qing-Yuan , Chen Da-Yuan
Published: February 2005

Conventional methods of somatic cell nuclear transfer either by electrofusion or direct nucleus injection have very low efficiency in animal cloning, especially interspecies cloning. To increase the efficiency of interspecies somatic cell nuclear transfer, in the present study we introduced a method of whole cell intracytoplasmic injection (WCICI) combined with chemical enucleation into panda–rabbit nuclear transfer and assessed the effects of this method on the enucleation rate of rabbit oocytes and the in vitro development and spindle structures of giant panda–rabbit reconstructed embryos. Our results demonstrated that chemical enucleation can be used in rabbit oocytes and the optimal enucleation result can be obtained. When we compared the rates of cleavage and blastocyst formation of subzonal injection (SUZI) and WCICI using chemically enucleated rabbit oocytes as cytoplasm recipients, the rates in the WCICI group were higher than those in the SUZI group, but there was no statistically siginificant difference (p>0.05) between the two methods. The microtubule structures of rabbit oocytes enucleated by chemicals and giant panda–rabbit embryos reconstructed by WCICI combined with chemical enucleation were normal. Therefore the present study suggests that WCICI combined with chemical enucleation can provide an efficient and less labor-intensive protocol of interspecies somatic cell nuclear transfer for producing giant panda cloned embryos.
A novel method for isolating spermatid nuclei from cytoplasm prior to ROSI in the mouse
Authors: Kishigami Satoshi , Van Thuan Nguyen , Wakayama Sayaka , Hikichi Takafusa , Wakayama Teruhiko
Published: February 2005

In the current widely used round spermatid injection (ROSI) protocol for the mouse, the spermatid nucleus is separated from most of the cytoplasm before ROSI by drawing a spermatid in and out of a pipette. This results in the highest rate of normal fertilization. However, this separation method is not always consistent and can be time-consuming. An alternative separation method that cuts away the cytoplasm using the tip of an injection pipette was developed. After removing the cytoplasm, ROSI was performed following both post- and pre-activation protocols and development in vitro and in vivo were examined. The new method consistently removed the bulk of the cytoplasm, as shown by quantifying mitochondria. ROSI without the cytoplasm resulted in significantly higher rates of fertilization than ROSI with the cytoplasm into either post- or pre-activated oocytes. Furthermore, the offspring production rates of ROSI without the cytoplasm were also high (50% and 49% for the post- and pre-activation protocols, respectively). This new method for separating the cytoplasm is an alternative way of producing offspring using ROSI.