bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rigid, Conjugated, Fluoresceinated Thymidine Triphosphates: Syntheses and Polymerase Mediated Incorporation into DNA Analogues
Authors: Thoresen Lars H. , Jiao Guan‐Sheng , Haaland Wade C. , Metzker Michael L. , Burgess Kevin 
Published: October 2003

AbstractSyntheses of a unique set of energy transfer dye labeled nucleoside triphosphates, compounds 1–3, are described. Attempts to prepare these compounds were only successful if the triphosphorylation reaction was performed before coupling the dye to the nucleobase, and not the other way around. Compounds were prepared as both the 2′‐deoxy (a) and 2′,3′‐dideoxy‐ (b) forms. They feature progressively longer rigid conjugated linkers connecting the nucleobase and the hydroxyxanthone moiety. UV spectra of the parent nucleosides 12–14 show that as the length of the linker increases so does the absorption of the donor in the 320–330 nm region, but with relatively little red‐shift of the maxima. Fluorescence spectra of the same compounds show that radiation in the 320–330 nm region results in predominant emission from the fluorescein. When the linker is irradiated at 320 nm, the only significant emission observed corresponds to the hydroxyxanthone part of the molecules at 520 nm; this corresponds to an effective Stokes' shift of 200 nm. As the absorption at 320–330 nm by the linker increases with length, so does the intensity of the fluorescein emission. A gel assay was used to gauge relative incorporation efficiencies of compounds 1–3, dTTP, ddTTP, and 6‐TAMRA‐ddTTP. Throughout, the thermostable polymerase TaqFS was used, as it is the one most widely applied in high throughput DNA sequencing. This assay showed that only compounds 3 were incorporated efficiently; these have the longest linkers. Of these, the 2′‐deoxy nucleoside 3 a was incorporated and did not prevent the polymerase from extending the chain further. The 2′,3′‐dideoxy nucleoside 3 b was incorporated only about 430 times less efficiently than ddTTP under the same conditions, and caused chain termination. The implications of these studies on modified sequencing protocols are discussed.
Bonding of Multiple Noble‐Gas Atoms to CUO in Solid Neon: CUO(Ng)n (Ng=Ar, Kr, Xe; n=1, 2, 3, 4) Complexes and the Singlet–Triplet Crossover Point
Authors: Liang Binyong , Andrews Lester , Li Jun , Bursten Bruce E. 
Published: October 2003

AbstractLaser‐ablated U atoms co‐deposited with CO in excess neon produce the novel CUO molecule, which forms distinct Ng complexes (Ng=Ar, Kr, Xe) with the heavier noble gases. The CUO(Ng) complexes are identified through CO isotopic and Ng reagent substitution and comparison to results of DFT frequency calculations. The U–C and U–O stretching frequencies of CUO(Ng) complexes are slightly red‐shifted from neon matrix 1Σ+ CUO values, which indicates a 1A′ ground state for the CUO(Ng) complexes. The CUO(Ng)2 complexes in excess neon are likewise singlet molecules. However, the CUO(Ng)3 and CUO(Ng)4 complexes exhibit very different stretching frequencies and isotopic behaviors that are similar to those of CUO(Ar)n in a pure argon matrix, which has a 3A″ ground state based on DFT vibrational frequency calculations. This work suggests a coordination sphere model in which CUO in solid neon is initially solvated by four or more Ne atoms. Up to four heavier Ng atoms successively displace the Ne atoms leading ultimately to CUO(Ng)4 complexes. The major changes in the CUO stretching frequencies from CUO(Ng)2 to CUO(Ng)3 provides evidence for the crossover from a singlet ground state to a triplet ground state.
Reaction of Alkyn‐1‐yl(diorganyl)silanes with 1‐Boraadamantane: Si‐H‐B Bridges Confirmed by the Molecular Structure in the Solid State and in Solution
Authors: Wrackmeyer Bernd , Milius Wolfgang , Tok Oleg L. 
Published: October 2003

Abstract1‐Boraadamantane 1 was treated with alkyn‐1‐ylsilanes 2 containing one or two SiH functions. Under mild conditions, the reaction gave 4‐methylene‐3‐borahomoadamantane derivatives 4 quantitatively and selectively by 1,1‐organoboration. An electron deficient Si‐H‐B bridge was present in the product. The analogous reaction of 1 with an alkyn‐1‐yl‐disilane 3 gave the corresponding alkene derivative 5, however, without the Si‐H‐B bridge. Evidence for the Si‐H‐B bridge in 4 was given by IR data, an extensive set of NMR spectroscopical data (1H, 11B, 13C, 29Si NMR) including various unusual isotope effects on chemical shifts and coupling constants, as well as from the molecular structure of one example, 4 e, in the solid state. The precursor of 4 e, alkyne 2 e, Ph2Si(H)CCSi(H)Ph2, was also studied by X‐ray analysis.
Synthesis and Characterization of New Biphenolate and Binaphtholate Rare‐Earth‐Metal Amido Complexes: Catalysts for Asymmetric Olefin Hydroamination/Cyclization
Authors: Gribkov Denis V. , Hultzsch Kai C. , Hampel Frank 
Published: October 2003

AbstractMonomeric diolate amido yttrium complexes [Y{diolate}{N(SiHMe2)2}(thf)2] can be prepared in good yield by treating [Y{N(SiHMe2)2}3(thf)2] with either 3,3′‐di‐tert‐butyl‐5,5′,6,6′‐tetramethyl‐1,1′‐biphenyl‐2,2′‐diol (H2(Biphen)), 3,3′‐bis(2,4,6‐triisopropylphenyl)‐2,2′‐dihydroxy‐1,1′‐dinaphthyl (H2(Trip2BINO)) or 3,3′‐bis(2,6‐diisopropylphenyl)‐2,2′‐dihydroxy‐1,1′‐dinaphthyl (H2(Dip2BINO)) in racemic and enantiopure form. The racemic complex [Y(biphen){N(SiHMe2)2}(thf)2] dimerizes upon heating to give the heterochiral complex (R,S)‐[Y(biphen){N(SiHMe2)2}(thf)]2. The corresponding dimeric heterochiral lanthanum complex was the sole product in the reaction of H2(Biphen) with [La{N(SiHMe2)2}3(thf)2]. Single‐crystal X‐ray diffraction of both dimeric complexes revealed that the two Ln(biphen){N(SiHMe2)2}(thf) fragments are connected through bridging phenolate groups of the biphenolate ligands. The two different phenolate groups undergo an intramolecular exchange process in solution leading to their equivalence on the NMR timescale. All complexes were active catalysts for the hydroamination/cyclization of aminoalkynes and aminoalkenes at elevated temperature, with [Y((R)‐dip2bino){N(SiHMe2)2}(thf)2] being the most active one giving enantioselectivities of up to 57 % ee. Kinetic resolution of 2‐aminohex‐5‐ene proceeded with this catalyst with 6.4:1 trans selectivity to give 2,5‐dimethylpyrrolidine with a krel of 2.6.
Molecular Energy and Electron Transfer Assemblies Made of Self‐Organized Lipid‐Porphyrin Bilayer Vesicles
Authors: Komatsu Teruyuki , Moritake Miho , Tsuchida Eishun 
Published: October 2003

AbstractNovel molecular energy and electron transfer assemblies in vesicular form, which are made of self‐organized amphiphilic porphyrins bearing phospholipid‐like substituents (lipid‐porphyrins), have been photochemically characterized. Tetraphenylporphyrin (TPP) derivatives with four dialkylphosphocholine groups [free‐base (1 a), Zn2+ complex (1 b), and Fe3+ complex (1 c)] are spontaneously associated in water to form spherical unilamellar vesicles with a diameter of 100–150 nm. Exciton calculations based on the bilayered sheet model of 1 b, which has a porphyrin packing similar to that seen in the triclinic unit cell of the Zn2+TPP crystals, reproduced the Soret band bathochromic shift appearing in the aqueous solution of 1 b well. The UV/Vis absorption spectrum of the 1 a/1 b hybrid vesicles (molar ratio: 1/1) showed no electronic interaction between the two porphyrin chromophores in the ground state, but efficient intermolecular singlet–singlet energy transfer took place from the excited 1 b donors to the 1 a acceptor within the vesicle. Near‐field scanning optical microspectroscopy of the 1 a/1 b vesicles on a graphite surface also showed only free‐base porphyrin fluorescence. The efficiency of the energy transfer was 0.81 and the rate constant was 3.1×109 s−1. On the other hand, protoporphyrin IX bearing two alkylphosphocholine propionates (2) was incorporated into the 1 a or 1 c bilayer vesicles (ca. 100 nm ϕ, molar ratio: 1 a/2 or 1 c/2=10). The UV/Vis absorption spectrum showed that 2 was successfully anchored into the fluid alkylene region of the membrane without stacking. Photoirradiation (λex: 390 nm) of the 1 c/2 vesicles in the presence of triethanolamine led a vectorial electron transfer from the outer aqueous phase to the membrane center, which allowed reduction of the ferric ion of the Fe3+TPP platform.
The First Structural Characterisation of a Group 2 Metal Alkylperoxide Complex: Comments on the Cleavage of Dioxygen by Magnesium Alkyl Complexes
Authors: Bailey Philip J. , Coxall Robert A. , Dick Caroline M. , Fabre Sylvie , Henderson Louise C. , Herber Christian , Liddle Stephen T. , Loroño‐González Daniel , Parkin Andrew , Parsons Simon 
Published: October 2003

AbstractA new high‐yield synthesis of [(PhCH2)2Mg(thf)2] and [{(PhCH2)CH3Mg(thf)}2] via benzylpotassium has allowed a simple entry into benzylmagnesium coordination chemistry. The syntheses and X‐ray crystal structures of both [(η2‐Me2NCH2CH2NMe2)Mg(CH2Ph)2] and [η2‐HC{C(CH3)NAr′}2Mg(CH2Ph)(thf)] (Ar′=2,6‐diisopropylphenyl) are reported. The latter β‐diketiminate complex reacts with dioxygen to provide a 1:2 mixture of dimeric benzylperoxo and benzyloxo complexes. The benzylperoxo complex [{η2‐HC{C(CH3)NAr′}2Mg(μ‐η2:η1‐OOCH2Ph)}2] is the first example of a structurally characterised Group 2 metal–alkylperoxo complex and contains the benzylperoxo ligands in an unusual μ‐η2:η1‐coordination mode, linking the two five‐coordinate magnesium centres. The OO separation in the benzylperoxo ligands is 1.44(2) Å. Reaction of the benzylperoxo/benzyloxo complex mixture with further [η2‐HC{C(CH3)NAr′}2Mg(CH2Ph)(thf)] results in complete conversion of the benzylperoxo species into the benzyloxo complex. This reaction, therefore, establishes the cleavage of dioxygen by this system as a two‐step process that involves initial oxygen insertion into the MgCH2Ph bond followed by OO/MgC σ‐bond metathesis of the resulting benzylperoxo ligand with a second MgCH2Ph bond. The formation of a 1:2 mixture of the benzylperoxo and benzyloxo species indicates that the rate of the insertion is faster than that of the metathesis, and this is shown to be consistent with a radical mechanism for the insertion process.
Complementary Nucleobase Interaction Enhances Peptide–Peptide Recognition and Self‐Replicating Catalysis
Authors: Matsumura Sachiko , Takahashi Tsuyoshi , Ueno Akihiko , Mihara Hisakazu 
Published: October 2003

AbstractThe availability of the complementary interaction of nucleobases for influencing the formation of peptide architectures was explored. Nucleobases were incorporated as additional recognition elements in coiled‐coil peptides by employing nucleobase amino acids (NBAs), which are artificialL‐α‐aminoγ‐nucleobase‐butyric acids. The effect of the base‐pair interaction on intermolecular recognition between peptides was evaluated through a self‐replication reaction. The self‐replication reactions of the peptides with complementary base pairs such as thymine–adenine or guanine–cytosine at theg–g′ heptad positions were accelerated in comparison with those of the peptides with mismatched base pairs or without nucleobases. However, thymine–adenine pairs at thee–e′ positions did not enhance the self‐replication. In the presence of a denaturant, the enhancement effects of complementary base pairs on the reaction disappeared. Thermal denaturation studies showed that the thymine–adenine pairs contributed to stabilization of the coiled‐coil structure and that the pairs at theg–g′ positions were more effective than those at thee–e′ positions. The peptide–peptide interaction was reinforced by complementary nucleobase interactions appropriately arranged in the peptide structure; these led to acceleration of the self‐replication reactions.
Wasser, Wäsche, Umwelt: Alles sauber?
Authors: Glathe Stefanie , Schermer Detlef 
Published: October 2003

AbstractDie zeit‐ und kräfteraubende große Wäsche am Fluss hat sich heute in Waschmaschinen mit Mikrochip‐Prozessoren zu einem hochtechnisierten Vorgang entwickelt. Trotzdem sind die beteiligten Faktoren Zeit, Chemie, Mechanik und Temperatur dieselben geblieben, allein ihre Gewichtung hat sich verschoben. Die Optimierung der Wirksamkeit der Waschmittel und des Waschprozesses muss möglichen Gewässer‐ und anderen Umweltbelastungen gegenübergestellt werden. Der Artikel beleuchtet Lösungsansätze für die Balance zwischen Produktleistung und Ökologie des Waschens am Beispiel der wichtigsten Waschmittelinhaltsstoffe.
Apoptose als Therapie
Authors: Feil Sylvia 
Published: October 2003

AbstractWird eine Pigment bildende Zelle durch einen Sonnenbrand geschädigt, kann sich daraus über eine Spanne von mehreren Jahrzehnten ein Tumor entwickeln. Dabei entzieht sich das Melanom — der schwarze Hautkrebs — sehr nachhaltig der Immunabwehr, deren wichtiges Werkzeug die Apoptose ist. Hier wollen Dermatologen und Molekularbiologen von der Freien Universität Berlin ansetzen.
Roaming times of multi‐wireless systems for software defined radio
Authors: Wei YingRao , Elhakeem A. K. 
Published: October 2003

AbstractIn this paper, we evaluate the roaming time performance for a reconfigurable multi‐mode mobile station (MS) that experiences possible transition from one kind of wireless system standard to another. In future software defined radio systems (SDR) (IEEE Commun Mag 2000; 138–143, IEE 1998; 1–6, IEEE 1999; 1212–1216, IEEE Commun Mag 1995; 33), reconfigurability of the MS is achieved by downloading the system configuration software code over the wireless channel. For evaluation of the roaming times, a generalized state diagram of the multi‐mode MS is presented. We focus on evaluating the times for sensing the universal pilot channel, classic base station pilot channel, association and connection establishment signaling are included. We investigate the effects of packet successful transmission probability over the wireless channel. We also consider the effects of the system resource blocking probability, MS resource blocking probability, and signaling bit rate over the universal base station channel for different cases and design scenarios. Such evaluations are important for prior design of SDR mobile terminal and universal base station in global roaming situations. We include some analysis results from many obtained. These show the feasibility of wireless software download, and switching between different wireless standard as the mobile station roams. Copyright © 2003 John Wiley & Sons, Ltd.
Analysis of resequencing in downloads
Authors: Nebat Yoav , Sidi Moshe 
Published: October 2003

AbstractRecent studies indicate that out‐of‐order arrival of data packets during downloads of resources is not pathological network behaviour (ACM/IEEE Trans. Networking 1999; 7(6):789). Though this situation is most intuitive when packets of the same resource arrive in parallel from several sources, it turns out that this phenomenon may also occur in the single source scenario. Knowledge regarding the expected reordering needed is important both for being able to decide on the size of the resequencing buffer needed, and to estimate the burstiness in arrival of data to the application. In this study we present a method to calculate the resequencing buffer occupancy probabilities for the single source scenario, and a study of the resequencing buffer occupancy for the two source scenario, where arrival from each of the sources is in order. Copyright © 2003 John Wiley & Sons, Ltd.
An adaptive quality of service channel borrowing algorithm for cellular networks
Authors: Habib Ibrahim , Sherif Mahmoud , Naghshineh Mahmoud , Kermani Parviz 
Published: October 2003

AbstractA multimedia call consists of three main sub‐streams (i.e. video, audio and data) each with its own distinct quality of service (QoS) requirements (e.g. packet loss rate, delay tolerance, and jitter). These requirements constitute a specific fixed QoS level. In contrast to static approaches, we propose an adaptive QoS platform in which each sub‐stream declares a preset range of acceptable QoS levels (e.g. maximum, acceptable, minimum) instead of just a single level. This range of QoS levels is pre‐defined in a user‐defined profile (UDP). In this paper, we propose a channel borrowing algorithm based on such adaptive QoS platform. In our proposed algorithm, an acceptor cell that has used all its channels can borrow from any neighbouring (donor) cell as long as this donor cell has some channels available after satisfying a minimum QoS (minQ) level defined in the UDP. A donor cell that is assigning QoS levels (to calls under its coverage) higher than the minQ levels will declare those channels as available for borrowing by other acceptor cells. The criteria for choosing the free channel include not only the number of free channels, but also the QoS levels in the donor cell. The criteria are also extended to include the effect of channel locking on the number of free channels, and the QoS levels on the locked cells. The algorithm is not triggered unless it does not cause any call dropping in either the donor cell, or the cells affected by call blocking. In the meantime, the call blocking rate is significantly decreased while the offered load increases. Copyright © 2003 John Wiley & Sons, Ltd.
(Alkyl)(monocyclopentadienyl)niobium and ‐tantalum Complexes in Insertion Processes
Authors: Gómez Manuel 
Published: October 2003

AbstractAlkyl high‐valent early transition metal compounds are important organometallic species, particularly because their reactions with unsaturated molecules, such as carbon monoxide and organic isocyanides, are relevant to several industrial stoichiometric and catalytic processes. Recently, we have reported several studies concerning (alkyl)(monocyclopentadienyl) derivatives of group‐5 metals, including both synthetic aspects and chemical behaviour in insertion reactions. This Microreview is an account of this work, covering syntheses, structure, spectroscopic, and reactivity details that have been reported by us together with the most significant contributions from other authors. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
PdII, ZnII and AgI Complexes of Tetrakis(N‐7‐azaindolyl)benzene: Variation of Bonding Modes, Extended Structures and Luminescence
Authors: Song Datong , Wang Suning 
Published: October 2003

AbstractPdII, AgI and ZnII complexes of tetrakis(7‐azaindolyl)benzene (ttab), [(PdCl2)2(ttab)] (1), [(ZnCl2)2(ttab)] (2), [Ag(NO3)]2(ttab) (3a) and [Ag(NO3)(DMSO)]2(ttab) (3b) were synthesized and fully characterized by NMR spectroscopy, single‐crystal X‐ray diffraction and elemental analyses. The ttab ligand in these complexes displays two different bonding modes. In the PdII and ZnII complexes, the ttab ligand chelates to the metal center via two ortho 7‐azaindolyl groups (the ortho mode). In contrast, in the AgI complex, it chelates to the AgI ion via two meta 7‐azaindolyl groups (the meta mode). In the solid state, molecules of 1 and 2 form grid‐like extended structures that host solvent molecules such as DMSO and CH2Cl2. Compound 3a appears to be a coordination polymer and can be converted into compound 3b when dissolved in DMSO. A hydrogen bonded complex [Zn(O2CCF3)2(H2O)2](ttab) (4), which displays an unusual hydrogen bonded helical chain structure in the solid state, was also characterized. Except for compound 1, these new compounds all emit blue light when irradiated by UV radiation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A Room‐Temperature Route to Bismuth Nanotube Arrays
Authors: Yang Baojun , Li Cun , Hu Hanmei , Yang Xiaogang , Li Qiaowei , Qian Yitai 
Published: October 2003

AbstractA room‐temperature aqueous‐chemical route has been developed to synthesize a high proportion (above 80%) of bamboo‐raft‐like bismuth nanotube arrays using bismuth chloride and metallic zinc powder as reagents. The prepared Bi nanotubes have uniform diameters of approximately 3−5 nm and lengths from several hundred nanometers to several micrometers. HRTEM observations show that the axial direction of the prepared nanotubes is along the normal direction of the (012) lattice planes of the rhombohedral bismuth. The possible formation mechanism is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Oxosulfido Complexes of Platinum — (Ph3P)2Pt(S2O) and (Ph3P)4Pt2(μ‐S)(μ‐SO) — Their Formation and Properties
Authors: Ishii Akihiko , Murata Masami , Oshida Hideaki , Matsumoto Kimiyo , Nakayama Juzo 
Published: October 2003

AbstractThe platinum S2O complex [(Ph3P)2Pt(S2O)] (10) was obtained by S2O transfer reactions from tetrathiolane 2‐oxide (8), tetrathiolane 2,3‐dioxide (5), and pentathiane 3‐oxide (6) to [(C2H4)Pt(PPh3)2] (4). The S2O complex 10 further reacts with 4 to give a novel binuclear platinum complex 16, which is found to be a source of several platinum SnOm complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
2D Chiral Uranyl(VI) Coordination Polymers with Second‐Harmonic Generation Response and Ferroelectric Properties
Authors: Xie Yong‐Rong , Zhao Hong , Wang Xi‐Sen , Qu Zhi‐Rong , Xiong Ren‐Gen , Xue Xiang , Xue Ziling , You Xiao‐Zeng 
Published: October 2003

AbstractThe in situ hydrothermal reactions of UO2(NO3)2 with 1‐oxo‐4‐cyanopyridine (ocpy) and ethyl (S)‐lactate (e‐la) afforded two unprecedented chiral 2D neutral luminescent square grids, uranyl‐bis(1‐oxo‐4‐pyridylcarboxylate) UO2(opyca)2 (1) and homochiral uranyl‐bis[(S)‐lactate] (2). Their solid‐state structures, preliminary optical and photoluminescent properties are reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The outcomes of psychotherapy with adolescents: A practitioner‐friendly research review
Authors: Roberts Michael C. , Lazicki‐Puddy Tammy A. , Puddy Richard W. , Johnson Rebecca J. 
Published: October 2003

AbstractThis article summarizes the outcome findings of psychotherapy with adolescents through an examination of the research literature. In this problem‐focused review of the research literature, we consider adolescent treatment of anxiety disorders, depression, eating disorders, disruptive behavior disorders, multiple problems of adolescence, and health risk behaviors. The evidence base for the effectiveness of various psychotherapies for adolescents is mixed. Psychotherapy in general has been a ripe field in which unsupported approaches have grown, and this is certainly true for psychotherapeutic interventions with adolescents. Nonetheless, there is a growing body of evidence to support various types of interventions as effective for different presenting problems. Researchers and clinicians need to recognize the complexity of the diverse characteristics of adolescents, including variations of culture, race, ethnicity, gender, class, physical disability, family definitions and constellation, and sexual orientation. These require sensitivity, responsiveness, and competence by the therapist, but clinical research has not fully examined these considerations. © 2003 Wiley Periodicals, Inc. J Clin Psychol/In Session.
Transforming psychotherapy in order to succeed with adolescent boys: Male‐friendly practices
Authors: Kiselica Mark S. 
Published: October 2003

AbstractThe purpose of this article is to describe a “male‐friendly” therapeutic process with troubled adolescent boys. A male‐friendly process is one in which the therapist employs a wide variety of strategies and activities that are likely to appeal to male youth and that facilitate the establishment and maintenance of rapport. The nuances of practicing a male‐friendly approach are highlighted and then applied in a case study of psychotherapy with a depressed adolescent boy. The implications of this approach for redefining professional conceptions about boundaries in the client–therapist relationship and reexamining inaccurate stereotypes about the emotional lives of boys are discussed. © 2003 Wiley Periodicals, Inc. J Clin Psychol/In Session.