bluuebunny/crossref_metadata_2025 huggingface dataset:
Steel bridges
Authors: Kuhlmann U
Published: December 2005

With recent developments, structural engineers are realizing that the quality of their structures is not only bound by economics, function and feasibility, but also aesthetics. The special quality of steel to allow high forces in very slender members is able to meet these new aesthetic requirements.

Tough economic competition between the concrete and steel industries has led to a decrease in the number of small and medium‐size steel bridges compared with concrete bridges. The bridges which have been built recently as steel structures, in spite of economic competition, are typically those which span a very long distance with an especially light structure. Examples are the Akashi‐Kaikyo Bridge in Japan, the Storebaelt East Bridge in Denmark and the Normandy Bridge in France. Other recently built steel bridges have been those which have to carry especially high loads over a long span since steel structures combine relatively light weight with high stiffness.

Steel bridges worldwide have been growing old. Deciding whether to replace or repair them, mainly depends on their physical condition, especially the degree of fatigue and their state of corrosion. Increasing traffic demands are the main reason for modifications and extensions to existing steel bridges. Seismic evaluation studies recommend the retrofitting of bridges that are at risk. Besides these functional considerations, some bridges are repaired because of their historical and architectural significance; this is a sign of a new perception of bridges as part of our cultural environment.
Seismic‐resistant steel moment connections: developments since the 1994 Northridge earthquake
Authors: Engelhardt Michael D , Sabol Thomas A
Published: December 2005

Since the 1994 Northridge earthquake, major changes have occurred in US design and construction practice for seismic‐resistant steel moment connections. These changes, motivated by the widespread failure of welded moment‐resisting beam‐to‐column connections in the Northridge earthquake, hold the promise of significantly better connection performance in future strong earthquakes. While the debate and discussion on these connection failures continues, intensive research and testing efforts have led to major advances in diagnosing the causes of the failures, and in developing improved connections. This paper presents a summary of key US developments in seismic‐resistant steel moment connections since the Northridge earthquake. A description of the typical moment connection detail in use prior to the earthquake is provided first, together with a description of damage observed at these connections after the earthquake. This is followed by a discussion of some of the major causes of the failures. Finally, some of the approaches currently being used in the US for the design and construction of improved moment connections are presented.
Seismic damage indices for RC buildings: evaluation of concepts and procedures
Authors: Kappos A J
Published: December 2005

This review clarifies the basic concepts involved in defining seismic damage indices for reinforced concrete buildings, and critically reviews the different schemes for classifying these indices. Typical examples are given for each class of indices, with emphasis on more recent studies. The available analytical procedures for the determination of damage indices are evaluated and the associated problems discussed. A brief reference is also made to empirical procedures for damage assessment. The most commonly used damage indices are evaluated in quantitative terms, using data from very recent comparative studies. Finally, conclusions are drawn, focusing on the practical use of these indices, and some directions for future research efforts are identified.
Seismic design of masonry structures
Authors: Tomaževič Miha
Published: December 2005

As a result of experimental and analytical research in seismic behaviour of masonry structures in the last few decades, new methods for seismic resistance analysis and design, as well as new, seismic resistant technologies and construction systems have been developed. After many centuries of traditional use, and decades of allowable stresses verification, clear concepts for limit states verification of seismic resistance of masonry structures have been introduced in the seismic codes. In this review, some basic aspects of seismic resistance verification of masonry walls and buildings are discussed, and some suggestions for future research are given.
Fatigue of tubular joints and fatigue improvement methods
Authors: Haagensen P J
Published: December 2005

This paper reviews important parameters and conditions that determine the life of welded joints, and summarizes recent research developments in the fatigue design of welded structures, with an emphasis on offshore tubular structures. Two of the factors that strongly affect fatigue life, the environment and plate thickness, have been the subject of several large research programs in recent years. With the increasing use of higher strength steels much interest has also been taken in various methods for improving the fatigue life of welded joints. Developments in these areas of research are reviewed. Examples of approaches to fatigue life prediction in design codes are given. Recent changes to design codes are evaluated, and examples of significant changes in design codes are given. Progress in the implementation of techniques for fatigue life improvement and life extension of fatigue‐damaged structures are discussed.
Fractures in seismically loaded bridges
Authors: Miki Chitoshi
Published: December 2005

During the Hanshin‐Awaji earthquake near Kobe, Japan, in January 1995, many civil structures suffered various kinds of damage which had never before been seen. Subsequently, many research programs have been undertaken which are related to the Hanshin‐Awaji earthquake and the associated damage. This paper reviews the currently conceived causes of the damage, particularly the fracture of steel bridge members. Related matters which should be given consideration in the future are also reviewed.
Creep and shrinkage analysis of composite beams
Authors: Dezi L , Leoni G , Tarantino A M
Published: December 2005

The principal aspects concerning long‐term behaviour of steel–concrete composite beams are illustrated by analysing separately the effects of static and geometrical actions, shrinkage and prestressing of the concrete slab. After having qualitatively described the time‐dependent phenomena which occur in composite beams, the most important methods of creep analysis are discussed. An accurate numerical solution can be obtained by means of the step‐by‐step procedure of the general method, that must necessarily be computer processed. Alternatively, single‐step solutions can be found by using approximated algebraic methods. The effectiveness of these simplified methods is subsequently estimated with reference to each single action. Finally, some practical design rules are provided in order to perform simplified creep analyses by means of pseudo‐elastic analyses.
Seismic isolation of civil buildings in Europe
Authors: Martelli A , Forni M
Published: December 2005

This review outlines the present state of applications of seismic isolation to civil buildings in Europe (with particular reference to Italy), including the countries formerly belonging to the USSR. Some information is also given on the use of other passive innovative antiseismic devices, like energy dissipators and shock transmitters, as well as on applications to bridges, viaducts and industrial plants. The adopted innovative antiseismic systems are described. Research projects, mainly in the framework of Programmes funded by the European Commission, which have been completed recently or are in progress, are briefly outlined. The available or proposed design rules and guidelines and statistics of applications (based on the outcome of recent international seminars) are included. Some examples of applications are briefly illustrated. Finally, the perspectives for future applications are discussed, highlighting the issues which have so far restrained a wider use of innovative antiseismic techniques in Europe.
Structural health monitoring of civil engineering structures
Authors: Culshaw B
Published: December 2005

Continuous monitoring to highlight the performance of major civil engineering structures is a process which to date has received relatively little attention. However, emerging legislation, the farreaching economic consequences of decay in the civil infrastructure, increasing social pressures and the changes in the contractual relationships between builder and user, all highlight the potential benefits which may accrue from the use of appropriate instrumentation. This article briefly examines the type of measurements which may be useful in civil engineering monitoring and some of the means whereby these measurements may be realized using the current and emerging instrumentation packages. The need for measurement functions over large areas, at very large numbers of sampling points, highlights the necessity for new instrumentation approaches, and of these, the global positioning system (GPS) and optical fibre sensor technology appear to offer particular promise. Signal processing and event recognition are also critical to the success of a monitoring system so this article provides a very basic introduction to the implicit requirements for data analysis.
Buckling analysis of thin‐walled structures: Analytical developments and applications
Authors: Rasmussen Kim J R , Hancock Gregory J
Published: December 2005

This article is the first part of a review of recent research in buckling analysis of thin‐walled structures. It covers fundamental developments in new methods of analysis and their applications. The second part of the review will be published in April 1999 and will focus on numerical developments based mainly on the finite element and finite strip methods, and applied research on specific types of thin‐walled structures, including stiffened panels, girders, shear panels and coldformed structural members.
Implementing advanced analysis for steel frame design
Authors: Chen W F
Published: December 2005

The recent development of a practical advanced analysis method for direct steel frame design is summarized. Since the method has been calibrated against the AISC/LRFD specification, it will produce almost identical member sizes to those of the LRFD method, without the tedious calculations of the effective length factor as well as the time‐consuming member‐by‐member capacity checks required by the Code. The aim is to provide a smooth transition from the current indirect LRFD analysis and design practice to the direct advanced analysis method suitable for use in engineering practice; the proposed practical theory and analysis procedures only require simple modifications of an existing inhouse elastic program that is widely available in current engineering practice.
Loads on bridges
Authors: Calgaro J‐A
Published: December 2005

Part 3 of Eurocode 1, published by the Comité Européen de Normalisation (CEN) in 1995 as ENV 1991‐3, defines traffic load models to be used for the design of road bridges, footbridges and railway bridges. These models have been selected and calibrated to cover the most common traffic effects with an appropriate margin of reliability. Scientific studies have been performed, based on real traffic data as far as such data were available and on various theoretical developments. ENV 1991‐3 is probably the most refined code in existence compared with similar national standards. Its content is systematically described in this review and some aspects of the background studies on road traffic loads are outlined.
Mixed singlet‐triplet superconducting state in doped antiferromagnets
Authors: Maci¸ag A. , Wróbel P.
Published: December 2005

We analyze symmetry mixing in the superconducting (SC) order parameter of planar cuprates. The behavior of thermal conductivity observed in some systems doped with magnetic impurities or in some systems exposed to external magnetic field seems to indicate that such symmetry mixing takes place. We discuss this phenomenon in the framework of the spin polaron model (SPM). We assume that antiferromagnetic (AF) correlations, which are at least of short range, tend to confine motion of holes which have been created in the AF spin background. The nature of the propagation of quasiparticles which are hole‐like and the nature of the interaction between quasiparticles is determined by a tendency to restore the local AF order. It is known that two holes in the t –J model (tJ M) form bound states with dx 2–y 2 or p‐wave symmetry. The d‐wave bound state has lower energy and is the ground state. The mixing of d‐wave symmetry with p‐wave symmetry takes place in the SC order parameter at some range of finite values of the doping parameter. That range lies at the applicability verge of the SPM, where AF correlation are already very short. On the other hand, these correlations may be strengthened by above mentioned external factors, which seems to explain why symmetry mixing is observed in this case. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The role of space‐charge‐induced electric field on transient photocurrent response in organic semiconductors
Authors: Pavlica E. , Bratina G.
Published: December 2005

The hopping model of charge‐carrier transport coupled to the Monte Carlo simulations was used to predict the time evolution of the photoinduced charge‐carrier current,I(t), through a layer of an organic semiconductor. Two electric‐field configurations inside the layer were considered: a uniform electric field and the electric field due to the injected space charge. A method to extract charge‐carrier mobility without a precise knowledge of the spatial dependence of the electric field is proposed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermodynamic properties of the Ising and Heisenberg S = 1 ferromagnet with biquadratic exchange and uniaxial anisotropy
Authors: Manojlović M. , Pantić M. , Škrinjar M. , Kapor D. , Stojanović S. , Pavkov M.
Published: December 2005

We study the thermodynamic properties of S = 1 Ising and Heisenberg ferromagnets with both bilinear and biquadratic exchange and/or uniaxial anisotropy of both easy axis/plane character. Using the mean‐field (MF) approximation we evaluated the free energy enabling us to study in detail the behavior of the order parameters and the dependence of the critical point on the anisotropy. We show that in the presence of biquadratic interaction, there is a difference in the behavior between the Ising and the Heisenberg model even in the MF approximation, which is not the case for the bilinear interaction. Combining the equations of motion for Green's functions with identities particular to S = 1, we managed to perform the random phase approximation without the decoupling of the operators at the same site, avoiding the peculiarities of the Callen–Anderson decoupling. This allowed us to improve the phase diagram for the Heisenberg model. The important result is the demonstration of the effect of anisotropy to nonvanishing of the quadrupolar order parameter at the Curie point. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homes relation in the attractive Hubbard model in d = ∞
Authors: Bak M.
Published: December 2005

Lack of the recognized theory of high‐temperature superconductivity (HTS) has led to an intense experimental and theoretical search for some universal relationships, which might unravel the physics behind the HTS. One of the most known is so called Uemura relation, ρ s(0) ∝ T c, where ρ s is superfluid density and T c is the superconducting transition temperature. Recently Homes et al. [Nature 430, 539 (2004)] reported a new universal scaling relation, ρ s ∝ σ dc(T c) · T c, where σ dc(T ) is dc conductivity. In the present paper Homes relation is investigated theoretically in the limit of infinite dimensions in the second order perturbation theory. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Zweifach und dreifach intramolekular verbrückte p‐tert‐Butylcalix[8]aren‐triphosphate – Synthese, Struktur und Stereochemie
Authors: Gloede Jörg , Ozegowski Sigrid , Keitel Iris , Buttke Klaus , Gruner Margit , Costisella Burkhard , Pritzkow Wolfgang , Stephan Holger , Bartoschek Michael
Published: December 2005

Two‐ and Threefold Intramolecular Brigdging p‐tert‐Butylcalix[8]arene Triphosphates – Synthesis, Structure and Stereochemistry [1]

The phosphorylation of p‐tert‐butylcalix[8]arene (1) with phosphorus pentachloride and hydrolysis gives intramolecular bridging tert‐butylcalix[8]arene triphosphates. The reactivity (esterification, dehydratisation, complexation), the structure (nmr and x‐ray), and the stereochemical behaviour of the phosphates will be discussed.
Quecksilber(II)‐chlorid‐ und ‐iodid‐Komplexe von Dithia‐ und Tetrathiakronenethern
Authors: Holdt Hans‐Jürgen , Müller Holger , Kelling Alexandra , Drexler Hans‐Joachim , Müller Thomas , Schwarze Thomas , Schilde Uwe , Starke Ines
Published: December 2005

Mercury(II) Chloride and Iodide Complexes of Dithia‐ and Tetrathiacrown Ethers

The complexes [(HgCl2)2((ch)230S4O6)] (1), [HgCl2(mn21S2O5)] (2), [HgCl2(ch18S2O4)] (3) and [HgI(meb12S2O2)]2[Hg2I6] (4) have been synthesized, characterized and their crystal structures were determined. In [(HgCl2)2((ch)230S4O6)] two HgCl2 units are discretely bonded within the ligand cavity of the 30‐membered dichinoxaline‐tetrathia‐30‐crown‐10 ((ch)230S4O6) forming a binuclear complex. HgCl2 forms 1 : 1 “in‐cavity” complexes with the 21‐membered maleonitrile‐dithia‐21‐crown‐7 (mn21S2O5) ligand and the 18‐membered chinoxaline‐dithia‐18‐crown‐6 (ch18S2O4) ligand, respectively. The 12‐membered 4‐methyl‐benzo‐dithia‐12‐crown‐4 (meb12S2O2) ligand gave with two equivalents HgI2 the compound [HgI(meb12S2O2)]2[Hg2I6]. In the cation [HgI(meb12S2O2)]+ meb12S2O2 forms with the cation HgI+ a half‐sandwich complex.
New Aquapentachlorochromate(III) Compounds: K2[CrCl5(H2O)] and (NH4)2[CrCl5(H2O)]
Authors: Casari Barbara M. , Eriksson Annika K. , Langer Vratislav
Published: December 2005

Synthesis and crystal structures of two new compounds, K2[CrCl5(H2O)] (I) and (NH4)2[CrCl5(H2O)] (II) are reported. Both compounds were prepared from chromium(VI) salts by two different methods and reaction pathways of these syntheses are suggested. The crystal structures of these two aquapentachlorochromates(III) have been determined from three dimensional X‐ray data collected at low temperature, 173 K. The two structures are isomorphous and their unit cell dimensions are quite similar. They are orthorhombic, space groups Pnma, with Z = 4. Both structures are composed of [CrCl5(H2O)]2− units held together by the counterion framework. The coordination around the chromium ion deviates from a regular octahedron due to the shorter equatorial chromium‐oxygen bond.
Novel Complexes of Gallium(III), Indium(III), and Thallium(III) with Pyridine‐Containing Proton Transfer Ion Pairs Obtained from Dipicolinic Acid – Synthesis, Characterization and X‐ray Crystal Structure
Authors: Aghabozorg Hossein , Ramezanipour Farshid , Kheirollahi Parvaneh D. , Saei Ali A. , Shokrollahi Ardeshir , Shamsipur Mojtaba , Manteghi Faranak , Soleimannejad Janet , Sharif Mahboubeh A.
Published: December 2005

Three new complexes of group thirteen metals, gallium(III), indium(III), and thallium(III) with proton transfer compounds, obtained from 2,6‐pyridinedicarboxylic acid (dipicolinic acid), were synthesized and characterized using elemental analysis, IR, 1H and 13C NMR spectroscopy and single crystal X‐ray diffraction. The gallium(III) and indium(III) complexes were prepared using (pydaH2)(pydc) (pyda = 2,6‐pyridinediamine, pydcH2 = dipicolinic acid) and thallium(III) complex was obtained from (creatH)(pydcH) (creat = creatinine). The chemical formulae and space groups of the complexes are (pydaH)[Ga(pydc)2] · 3.25H2O · CH3OH, $P{\bar 1}$ (1), [In(pydc)(pydcH)(H2O)2] · 5H2O, Pna21 (2) and [Tl2(pydcH)3(pydc)(H2O)2], $P{\bar 1}$ (3). Non‐covalent interactions such as ion‐pairing, hydrogen bonding and π‐π stacking are discussed. The complexation reactions of pyda, pydc, and pyda + pydc with In3+ and Ga3+ ions in aqueous solution were investigated by potentiometric pH titrations, and the equilibrium constants for all major complexes formed are described.
A New Family of Binary Layered Compounds of Platinum with Alkali Metals (A = K, Rb, Cs)
Authors: Karpov Andrey , Jansen Martin
Published: December 2005

By reacting platinum with alkali metals (A = K, Rb, Cs) a new family of binary alkali metal platinides has been synthesized and characterized by chemical analysis, X‐ray powder diffraction, thermal analysis (DTA and DSC), and magnetic measurements. All three compounds exhibit similar XRD‐patterns with strong reflections that can be indexed on the basis of a rhombohedral crystal system (KxPt: a = 2.6462(1), c = 17.123(1); RbxPt: a = 2.6415(1) Å, c = 17.871(1) Å; CsxPt: a = 2.6505(1) Å, c = 18.536(1) Å; x < ½. The a lattice constant is independent on the alkali metal used and of value close to the Pt–Pt distance in NaPt2 (2.645Å). The c parameter increases monotonically with the growing atomic radius of the alkali metal. The average structure of the alloys consists of cubic close packed layers of platinum atoms with layers of disordered alkali metals in between. For all compounds besides the strong reflections small satellites are observed which cannot be indexed together with the rhombohedral peaks in any rational 3‐dimensional lattice. However, these satellites can be indexed as incommensurate modulations within the ab plane (found propagation vectors k = (0.1011, 0.2506, 0) for CsxPt, and k = (0.0168, 0.2785, 0) for RbxPt).
The Molecular Structure of the 1:1 Adduct of Silver Cyanide with Tri(1‐cyclohepta‐2,4,6‐trienyl)phosphane, Ag(CN)[P(C7H7)3]
Authors: Herberhold Max , Milius Wolfgang , Akkus Nilgün
Published: December 2005

The complex Ag(CN)[P(C7H7)3] is the first (and so far only) mononuclear 1:1 derivative of AgCN with a tertiary phosphane ligand.
Ortho‐Chalcogenotetrelate Anions as Chelating Ligands: Syntheses and Characterization of [K6(MeOH)9][Sn2Se6][Cr(en)2(SnSe4)]2, [Na(H2O)4][Cr(en)3]2[GeS3OH]2[Cr(en)2(GeS4)], and [Ba(H2O)10][{Cr(en)}2(GeSe4)2]
Authors: Melullis Maike , Brandmayer Michael K. , Dehnen Stefanie
Published: December 2005

Reactions of K4[SnSe4], Na4[GeS4] or Ba2[GeSe4] with different 1,2‐diaminoethane (= en) coordinated complexes of CrCl3 ([Cr(en)2Cl2]Cl or [Cr(en)3]Cl3) in MeOH or aqueous solution yielded three novel compounds that contain complexes of Cr3+ with ortho‐chalcogenotetrelate anions [E′E4]4− (E′ = Ge, Sn; E = S; Se): the crystal structures of [K6(MeOH)9][Sn2Se6][Cr(en)2(SnSe4)]2 (1), [Na(H2O)4][Cr(en)3]2[GeS3OH]2[Cr(en)2(GeS4)] (2), and [Ba(H2O)10][{Cr(en)}2(GeSe4)2] (4) have been determined by means of single crystal X‐ray diffraction (1: triclinic space group $P{\bar 1}$; lattice dimensions at 203 K: a = 1175.7(2), b = 1315.3(3), c = 1326.7(3) pm, α = 61.99(3)°, β = 64.05(3)°, γ = 83.57(3)°, V = 1617.4(6)·106 pm3; R1 [I > 2σ(I)] = 0.0788; wR2 = 0.1306; 2: monoclinic space group C2/c; lattice dimensions at 203 K: a = 2445.3(5), b = 1442.5(3), c = 1579.3(3) pm, β = 94.61(3)°, V = 5552.9(19)·106 pm3; R1 [I > 2σ(I)] = 0.0801; wR2 = 0.2046; 4: triclinic space group $P{\bar 1}$; lattice dimension at 203 K: a = 1198.4(2), b = 1236.8(3), c = 1297.5(3) pm, α = 65.69(3)°, β = 63.35(3)°, γ = 81.21(3)°, V = 1565.2(5)·106 pm3; R1 [I > 2σ(I)] = 0.0732; wR2 = 0.1855). 1 and 2 show the yet unprecedented complexation of transition metal ions by non‐bridging, single chalcogenotetrelate ligands to produce dinuclear, heterobimetallic complexes. Compound 2 contains the first structurally characterized complex with an ortho‐thiogermanate ligand. The formation of these compounds, and of a by‐product of 2, [Cr(en)3][GeS3OH]·6H2O (3: monoclinic space group C2/c; lattice dimensions at 203 K: a = 2396.8(5), b = 1463.4(3), c = 1740.1(4) pm, β = 132.99(3)°, V = 4463.8(15)·106 pm3; R1 [I > 2σ(I)] = 0.0462; wR2 = 0.1058), provides some insight in fundamental differences between the reaction behavior of [SnE4]4− anions one the one hand and [GeE4]4− anions on the other hand. The crucial role of the counterion charge becomes evident when comparing the structure motifs of the ternary anions in 1 and 2 with that observed in the Ba2+ compound 4.
High‐Pressure Synthesis and Physical Properties of the Europium‐Substituted Barium Clathrate Ba8−xEuxGe43□3 (x ≤ 0.6)
Authors: Demchyna R. , Köhler U. , Prots Yu. , Schnelle W. , Baenitz M. , Burkhardt U. , Paschen S. , Schwarz Ulrich
Published: December 2005

The new clathrate Ba8–xEuxGe43□3 (x = 0.6) was synthesized at a pressure of 1 GPa and temperatures of up to 1220 K by means of a multi‐anvil device (Walker module) and a hydraulic 1000 ton press. X‐ray powder diffraction data indicate that the crystal structure of Ba8–xEuxGe43□3 (x = 0.6, space group $Ia{\bar 3}d$, a = 21.2588(3) Å) corresponds to that of Ba8Ge43□3. Measurements of the magnetic susceptibility of Ba8–xEuxGe43□3 reveal Curie‐paramagnetic behaviour and prove that the electronic state of europium corresponds to 4f7, i.e., Eu2+. Electrical resistivity shows a metal‐like temperature dependence and ρ(300) ≈ 2mΩ cm for x = 0.6. Heat capacity measurements reveal an upturn of cp/T(T) below 7 K that is attributed to magnetic interaction of the europium ions.
The Helical Coordination Polymer Ag(Nic)2(NO3)
Authors: Meyer Gerd , Berners Alexandra , Pantenburg Ingo
Published: December 2005

Single crystals of Ag(Nic)2(NO3) were obtained from an aqueous solution of silver nitrate and nicotine as plate‐like colourless crystals. The crystal structure (monoclinic, P21, Z = 2, a = 933.3(2), b = 1136.8(2), c = 1024.3(2) pm, β = 94.49(2)°) consists of helical chains in which one nicotine molecule bridges with both the pyridine‐N and the pyrrol‐N coordinating and with a second nicotine molecule terminally coordinating with the pyridine‐N. A monodentate nitrate‐O is completing the coordination sphere of Ag+ to a distorted tetrahedron. Ag–N distances (229‐240 pm) attest for a rather strong attraction of the nicotine molecules to Ag(I) and thereby constitute essentially a one‐dimensional, helical coordination polymer according to the formulation Ag(Nic1)2/2(Nic2)1/1(NO3)1/1.
The Role of Substitutional Defects in Order/Disorder Phenomena of OH− Ions in Hydroxyapatite
Authors: Zahn Dirk , Hochrein Oliver
Published: December 2005

We report on density functional quantum mechanical calculations of hydroxyapatite. The central focus is dedicated to the local arrangement of hydroxide ions in proximity of defects originating from substituting OH− by F− or O2− ions. At ambient conditions the preferred structure of bulk hydroxyapatite exhibits an ordering of OH− ions oriented in rows along the [001] direction. From zero Kelvin geometry optimizations the orientation inversion of a hydroxide ion was found to be disfavored by 0.165 eV. This picture changes dramatically when replacing one of the OH− ions by a fluoride ion. The preferred hydroxide ion arrangement next to the F− defect was identified as an OH−··F−··HO− constellation, which implies the orientation inversion of one of the neighboring hydroxide ions. An analogous phenomenon was observed for O2− defects.
Lou Harrison and the Aesthetics of Revision, Alteration, and Self-Borrowing
Authors: MILLER LETA E.
Published: December 2005

Lou Harrison seems always to have been re-examining his older works, revising or updating them, reworking them into movements of longer compositions, or creating alternative versions. This article examines Harrison’s revisions, alterations, and self-borrowings in terms of both technique and aesthetic objectives. Harrison’s first reworking of a set of short pieces into an extended composition, the Suite for Symphonic Strings of 1960, resulted in a poly-stylistic work he found so attractive that he not only used the self-borrowing technique in later works (such as the Third Symphony) but also incorporated similar contrasts in most of his long works, whether or not they were based on recycled materials. Thus the process of revision and self-borrowing in itself helped Harrison develop a distinctive personal style – one marked by its own eclecticism.
On Musical Mediation: Ontology, Technology and Creativity
Authors: BORN GEORGINA
Published: December 2005

This article develops a theoretical analysis of music and mediation, building on the work of Theodor Adorno, Tia DeNora and Antoine Hennion. It begins by suggesting that Lydia Goehr’s account of the work concept requires such a perspective. Drawing on Alfred Gell’s anthropology of art, the article outlines an approach to mediation that incorporates understandings of music’s social, technological and temporal dimensions. It suggests that music’s mediations have taken a number of historical forms, which cohere into assemblages, and that we should be alert to shifts in the dominant forms of musical assemblage. In the latter part of the article, these tools are used to conceptualize changing forms of musical creativity that emerged over the twentieth century. A comparison is made between the work concept and jazz and improvised electronic musics. Three contemporary digital music experiments are discussed in detail, demonstrating the concepts of the provisional work and of social, distributed and relayed creativity. Throughout, key motifs are mediation, creativity, and the negotiation of difference.
Editorial
Authors: Adlington Robert , Fuller Sophie
Published: December 2005

Nottingham, 1 May 2004: the Kamkars, a group of Kurdish musicians from Iran, close a concert with a flamboyant instrumental encore based upon a song performed earlier in the evening.
Learning with solar activity influence on Portugal's rainfall: A stochastic overview
Authors: Lucio Paulo S.
Published: December 2005

The major goal of this manuscript is the improvement of a methodology to predict rainfall as a function of time; how far the solar activities and other components of the climate system are alternatives. For this purpose one makes use of computer simulation environment with neural network and stochastic analyses. The possible statistically significant correlation between sunspot numbers and regional precipitation was investigated, considering thirteen (13) meteorological stations over Portugal mainland in the period of 1951–2004. The data analysis shows signs that the relationship between the solar activity and the climate of Portugal is in any way exceptional. Possibly, the Portuguese climate system (primarily considering rainfall) is more sensitive to sensible variations in solar activity than generally believed! The conclusion highlight the use of solar activity response as potential climate or rainfall predictor, even though the relative importance of sunspot numbers compared to established meteorological factors responsible for rainfall is probably hard to quantify.
Emission of dimethylsulfide from Weddell Sea leads
Authors: Zemmelink H. J. , Houghton L. , Dacey J. W. H. , Worby A. P. , Liss P. S.
Published: December 2005

The distribution of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) was examined in lead water in pack ice of the Weddell Sea. Samples were taken by pulling water into a syringe from a series of depths from 0.002 m to 4 m and deeper. Concentrations of DMS, DMSP and DMSO remained low throughout the water column relative to surface water, which was highly enriched. Concentrations of the major sulfur compounds increased by over an order of magnitude during periods with smooth surface water conditions. This increase coincided with a profound stratification of the water column, caused by a decrease in salinity of near surface water. We estimate that the DMS emission from leads and open water in Antarctic sea ice could contribute significantly to the yearly DMS flux from the Southern Ocean.
Direct thermal radiative forcing of tropospheric aerosol in the Arctic measured by ground based infrared spectrometry
Authors: Ritter Christoph , Notholt Justus , Fischer Jürgen , Rathke Carsten
Published: December 2005

We present, to our knowledge for the first time in the high Arctic, atmospheric thermal emission spectra recorded by ground‐based FTIR spectrometry revealing an excess emission contribution, which can only be attributed to the presence of tropospheric aerosols. Consideration of direct thermal forcing in climatological sensitive and remote regions as the Arctic seems to be important for more realistic modelling. According to our measurements, the aerosols can alter the flux density of downward longwave radiation by up to +2.99 to +4.66 W m−2, and the flux density of outgoing longwave radiation by −0.23 to +1.17 W m−2.
Morphometric analysis of Martian valley network basins using a circularity function
Authors: Luo Wei , Howard Alan D.
Published: December 2005

This paper employs a circularity function to quantify the internal morphology of Martian watershed basins in Margaritifer Sinus region and to infer the primary erosional processes that led to their current geomorphologic characteristics and possible climatic conditions under which these processes operated. The circularity function describes the elongation of a watershed basin at different elevations. We have used the circularity functions of terrestrial basins that were interpreted as having been modified by (1) erosion related to primarily groundwater sapping and (2) erosion related to primarily rainfall and surface run‐off, as well as the circularity functions of cratering basins on the Moon, in order to formulate discriminant functions that are able to separate the three types of landforms. The spatial pattern of the classification of Martian basins based on discriminant functions shows that basins that look morphologically similar to terrestrial fluvial basins are mostly clustered near the mainstream at low elevation, while those that look morphologically similar to terrestrial basins interpreted as groundwater sapping origin are located near the tributaries and at higher elevation. There are more of the latter than the former. This spatial distribution is inconsistent with a continuous Earth‐like warm and wet climate for early Mars. Instead, it is more aligned with an overall early dry climate punctuated with episodic wet periods. Alternatively, the concentrated erosion in the mainstream could also be caused by a change of water source from rainfall to snowfall or erosion cut through a duricrust layer.
First observation of a dihydrogen bond involving the Si–H group in phenol-diethylmethylsilane clusters by infrared-ultraviolet double-resonance spectroscopy
Authors: Ishikawa Haruki , Saito Akira , Sugiyama Masuyuki , Mikami Naohiko
Published: December 2005

We have experimentally identified a dihydrogen bond involving the Si–H group in phenol-diethylmethylsilane (DEMS) clusters for the first time by IR-UV double-resonance spectroscopy. Vibrational shifts to lower frequency of 21–29cm−1 were found for the OH stretching vibration of three isomers of the phenol-DEMS clusters. Spectral simulations based on the MP2 calculations also support our observation. In addition to these clusters, dihydrogen bonds were also observed in the phenol-H2O-DEMS and (phenol)2-DEMS clusters, which exhibited much stronger interactions than the phenol-DEMS clusters.
Gyro center invariant and associated diamagnetic current
Authors: Ågren O. , Moiseenko V. , Johansson C. , Savenko N.
Published: December 2005

The gyro center radial Clebsch coordinate r¯0 is an exact invariant in confining fields where the gyro center is restricted to move on a magnetic flux surface, and r¯0 could also be expected to be a useful approximating invariant in other confining magnetic fields. A radial drift invariant Ir generalizes the invariance of r¯0 if there are oscillatory gyro center radial displacements off the magnetic surface. Expressions for r¯0(x,v) and Ir(x,v) are obtained for gyrating particles in the drift ordering. An exact energy integral is proven to exist for the first-order drift motion of the gyro center. The gyro center parallel motion is periodic with respect to a certain curve parameter τ¯‖ (the “proper time” for the parallel motion) that deviates slightly, due to the slow perpendicular drift, from the ordinary time. A modification of the parallel invariant J‖ is derived which leads to an exact (not only adiabatic) invariant to first order. By using r¯0 in solutions of the Vlasov equation, it is demonstrated that the approximating gyro center invariant r¯0 determines the perpendicular plasma diamagnetic current. It is also shown that a fourth stationary motional invariant is required to calculate the parallel plasma current. Several systems with four time independent invariants are identified, and the general solution for straight cylindrical Vlasov equilibria with adiabatic particle motion is determined. A set (ε,μ,I‖,Ir) of four invariants is proposed for adiabatic equilibria in general geometry, including systems where single valued flux surfaces may not exist.
Modulation instability of laser pulse in magnetized plasma
Authors: Jha Pallavi , Kumar Punit , Raj Gaurav , Upadhyaya Ajay K.
Published: December 2005

Modulation instability of a laser pulse propagating through transversely magnetized underdense plasma is studied. It is observed that interaction of laser radiation with plasma in the presence of uniform magnetic field results in an additional perturbed transverse plasma current density along with the relativistic and ponderomotive nonlinear current densities, thus affecting the modulational interaction. In the plane wave limit it is observed that modulational interaction is more stable for magnetized plasma as compared to the unmagnetized case. The analysis shows that there is a significant reduction in the growth rate of modulation instability over a given range of unstable wave numbers due to magnetization of plasma.
Synthesis and Luminescent Properties of Mercury(II) Polyynes Containing Derivatized Benzene in the Backbone
Authors: Liu Li , Li Ming-Xuan , Wong Wai-Yeung
Published: December 2005

Group 12 mercury(ii) polyyne polymers containing derivatized benzene spacers were prepared in good yields using Hagihara’s dehydrohalogenation reaction of HgCl2 with HC≡C(C6H2R)2C≡CH (R = 4,5-dioctyloxy, 2,5-dihexadecyloxy) at room temperature in a basic medium. The structures of these polymers were confirmed by standard spectroscopic methods and their luminescent properties were examined. Our investigations indicate that two polymers exhibit different luminescence properties due to different position of the substituents on the benzene spacer.
The X-Ray Molecular Structure of 1-(2′,4′-Dinitrophenyl)-1,2,3-triazole and the Problem of the Orthogonal Interaction Between a 'Pyridine-Like' Nitrogen and a Nitro Group
Authors: Yap Glenn P. A. , Jové Fernando A. , Claramunt Rosa M. , Sanz Dionisia , Alkorta Ibon , Elguero José
Published: December 2005

The structure of the title compound serves for a discussion about the topic of orthogonal interactions. This interaction, although weak, is important due to its peculiar geometry. Other examples from the Cambridge Crystallographic Database, together with theoretical calculations are reported.
Driving the Localized-to-Delocalized Transition in Unsymmetrical Dinuclear Ruthenium Mixed-Valence Complexes
Authors: D'Alessandro Deanna M. , Keene F. Richard
Published: December 2005

The degree of delocalization in the symmetrical complexes [{Ru(bpy)2}2(μ-dpb′)]5+ and [{Ru(bpy)2}2(μ-dpb)]5+ (dpb = 2,3-bis(2-pyridyl)-1,4-benzoquinoxaline; dpb′ = dipyrido(2,3-a;3′,2′-c)benzophenazine; bpy = 2,2′-bipyridine) is diminished by the substitution of the terminal bpy ligands at one end of the complex. The results of a classical analysis for the diastereoisomeric forms of the series of complexes [{Ru(bpy)2}(μ-BL){Ru(pp)2}]5+ (pp = bpy, Me2bpy (4,4′-dimethyl-2,2′-bipyridine), Me4bpy (4,4′,5,5′-tetramethyl-2,2′-bipyridine)) indicate that a greater degree of ground-state delocalization exists in the complexes incorporating the bridging ligand dpb′ compared with the dpb analogue. A two-state analysis in which ΔE 0 (the redox asymmetry) is varied at constant H ab (the electronic coupling) and λ (the reorganizational energy) does not adequately describe the properties of the systems due to the importance of a third electronic state corresponding to the bridging ligand.
Depletion of minichromosome maintenance protein 5 in the zebrafish retina causes cell-cycle defect and apoptosis
Authors: Ryu Soojin , Holzschuh Jochen , Erhardt Simone , Ettl Anne-Kathrin , Driever Wolfgang
Published: December 2005

In multicellular organisms, the control of genome duplication and cell division must be tightly coordinated. Essential roles of the minichromosome maintenance (MCM) proteins for genome duplication have been well established. However, no genetic model has been available to address the function of MCM proteins in the context of vertebrate organogenesis. Here, we present positional cloning of a zebrafish
mcm5
mutation and characterization of its retina phenotype. In the retina,
mcm5
expression correlates closely with the pattern of cell proliferation. By the third day of development,
mcm5
is down-regulated in differentiated cells but is maintained in regions containing retinal stem cells. We demonstrate that a gradual depletion of maternally derived MCM5 protein leads to a prolonged S phase, cell-cycle-exit failure, apoptosis, and reduction in cell number in

mcm5
m850

mutant embryos. Interestingly, by the third day of development, increased apoptosis is detectable only in the retina, tectum, and hindbrain but not in other late-proliferating tissues, suggesting that different tissues may employ distinct cellular programs in responding to the depletion of MCM5.
Recombinant human nerve growth factor with a marked activityin vitroandin vivo
Authors: Colangelo Anna M. , Finotti Nicoletta , Ceriani Michela , Alberghina Lilia , Martegani Enzo , Aloe Luigi , Lenzi Laura , Levi-Montalcini Rita
Published: December 2005

Recombinant human nerve growth factor (rhNGF) is regarded as the most promising therapy for neurodegeneration of the central and peripheral nervous systems as well as for several other pathological conditions involving the immune system. However, rhNGF is not commercially available as a drug. In this work, we provide data about the production on a laboratory scale of large amounts of a rhNGF that was shown to possessin vivobiochemical, morphological, and pharmacological effects that are comparable with the murine NGF (mNGF), with no apparent side effects, such as allodynia. Our rhNGF was produced by using conventional recombinant DNA technologies combined with a biotechnological approach for high-density culture of mammalian cells, which yielded a production of ≈21.5 ± 2.9 mg/liter recombinant protein. The rhNGF-producing cells were thoroughly characterized, and the purified rhNGF was shown to possess a specific activity comparable with that of the 2.5S mNGF by means of biochemical, immunological, and morphologicalin vitrostudies. This work describes the production on a laboratory scale of high levels of a rhNGF within vitroand, more important,in vivobiological activity equivalent to the native murine protein.
The oncogenic properties of mutant p110α and p110β phosphatidylinositol 3-kinases in human mammary epithelial cells
Authors: Zhao Jean J. , Liu Zhenning , Wang Li , Shin Eyoung , Loda Massimo F. , Roberts Thomas M.
Published: December 2005

The
PIK3CA
gene encoding the p110α subunit of Class IA phosphatidylinositol 3-kinases (PI3Ks) is frequently mutated in human tumors. Mutations in the
PIK3CB
gene encoding p110β, the only other widely expressed Class IA PI3K, have not been reported. We compared the biochemical activity and transforming potential of mutant forms of p110α and p110β in a human mammary epithelial cell system. The two most common tumor-derived alleles of p110α,
H1047R
and
E545K
, potently activated PI3K signaling. Human mammary epithelial cells expressing these alleles grew efficiently in soft agar and as orthotopic tumors in nude mice. We also examined a third class of mutations in p110α, those in the p85-binding domain. A representative tumor-derived p85-binding-domain mutant R38H showed modestly reduced p85 binding and weakly activated PI3K/Akt signaling. In contrast, a deletion mutant lacking the entire p85-binding domain efficiently activated PI3K signaling. When we constructed in p110β a mutation homologous to the
E545K
allele of p110α, the resulting p110β mutant was only weakly activated and allowed minimal soft-agar growth. However, a gene fusion of p110β with the membrane anchor from c-Src was highly active and transforming in both soft-agar and orthotopic nude mouse assays. Thus, although introduction of activating mutations from p110α at the corresponding sites in p110β failed to render the enzyme oncogenic in human cells, the possibility remains that other mutations might activate the β isoform.
Poxvirus multiprotein entry–fusion complex
Authors: Senkevich Tatiana G. , Ojeda Suany , Townsley Alan , Nelson Gretchen E. , Moss Bernard
Published: December 2005

Poxviruses have evolved elaborate mechanisms for cell entry, assembly, and exocytosis. Recently, four vaccinia virus membrane proteins, namely A21, A28, H2 and L5, were reported to be necessary for cell entry and virus-induced cell–cell fusion but not for virion morphogenesis or attachment of virus particles to cells. Using immunoaffinity purification followed by mass spectrometry, we now show that these four proteins as well as four additional previously uncharacterized putative membrane proteins (A16, G3, G9, and J5) form a stable complex. These proteins fall into two groups: A21, A28, G3, H2, and L5 have an N-terminal transmembrane domain, 0–2 intramolecular disulfide bonds, and no sequence similarity, whereas A16, G9, and J5 have a C-terminal transmembrane domain and 4–10 predicted disulfide bonds and are homologous. Studies with conditional-lethal null mutants indicated that the viral membrane was crucial for assembly of the complex and that the absence of individual polypeptide components profoundly decreased complex formation or stability, suggesting a complicated interaction network. Analysis of purified virions, however, demonstrated that the polypeptides of the complex trafficked independently to the viral membrane even under conditions in which the complex itself could not be isolated. All eight proteins comprising the entry–fusion complex are conserved in all poxviruses, suggesting that they have nonredundant functions and that the basic entry mechanism evolved before the division between vertebrate and invertebrate poxvirus species.
Survival prediction of diffuse large-B-cell lymphoma based on both clinical and gene expression information
Authors: Li Lexin
Published: December 2005

Motivation: It is important to predict the outcome of patients with diffuse large-B-cell lymphoma after chemotherapy, since the survival rate after treatment of this common lymphoma disease is <50%. Both clinically based outcome predictors and the gene expression-based molecular factors have been proposed independently in disease prognosis. However combining the high-dimensional genomic data and the clinically relevant information to predict disease outcome is challenging.

Results: We describe an integrated clinicogenomic modeling approach that combines gene expression profiles and the clinically based International Prognostic Index (IPI) for personalized prediction in disease outcome. Dimension reduction methods are proposed to produce linear combinations of gene expressions, while taking into account clinical IPI information. The extracted summary measures capture all the regression information of the censored survival phenotype given both genomic and clinical data, and are employed as covariates in the subsequent survival model formulation. A case study of diffuse large-B-cell lymphoma data, as well as Monte Carlo simulations, both demonstrate that the proposed integrative modeling improves the prediction accuracy, delivering predictions more accurate than those achieved by using either clinical data or molecular predictors alone.

Availability: R programs are available at

Contact:  li@stat.ncsu.edu

Supplementary information: Supplementary data are available at