bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling stylized features in default rates
Authors: Taufer Emanuele
Published: August 2006

We propose a stochastic model for the probability of default based on diffusions with given marginal distribution and autocorrelation function. The model tries to capture stylized features observed in historical default rates and is analytically tractable. Estimation procedures and expressions for analysis and prediction are provided. Copyright © 2006 John Wiley & Sons, Ltd.
Structural and spectroscopic analysis of hydrogensquarates of glycine‐containing tripeptides
Authors: Koleva Bojidarka B. , Kolev Tsonko M. , Spiteller Michael
Published: August 2006

The hydrogensquarates of glycine‐containing tripeptides glycylglycylglycine (H‐Gly‐Gly‐Gly‐OH), glycylglycylmethionine (H‐Gly‐Gly‐Met‐OH), and methionylglycylglycine (H‐Met‐Gly‐Gly‐OH) have been characterized structurally. Quantum chemical ab initio calculations, solid‐state linear‐dichroic infrared (IR–LD) spectroscopy, 1H and 13C NMR data, ESI‐MS, HPLC‐MS/MS, TGV, and DSC methods were employed. The structures consist in a positively charged peptide moiety and a negative hydrogensquarate anion (HSq−), stabilized by strong intermolecular hydrogen bonds. © 2006 Wiley Periodicals, Inc. Biopolymers 83: 498–507, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
The chemical synthesis of the GstI protein by NCL on a X‐Met site
Authors: Saporito Angela , Marasco Daniela , Chambery Angela , Botti Paolo , Monti Simona M. , Pedone Carlo , Ruvo Menotti
Published: August 2006

The small GstI protein (63 amino acids) of Rhizobium leguminosarum is the endogenous inhibitor of the glnII (glutamine synthetase II) gene expression. It has been suggested that GstI has a predominantly β‐structure and mediates the block of translation and stabilization of glnII mRNA through direct binding to its 5′ untranslated region. Because of the unavailability of adequate amounts of purified recombinant protein, the mechanism as well as the protein tridimensional structure remain very poorly understood. To obtain the full‐length protein, we have undertaken the chemical synthesis of the protein by different approaches. In a first attempt, the stepwise synthesis was unsuccessful, with strong aggregation experienced on the N‐terminal side, after residue 44 from the C‐terminus. In a second approach, we set up the conditions to carry out a native chemical ligation (NCL). Albeit the protein contains two Cysteine residues, located at positions 40 and 47, to minimize the size of the N‐terminal segment to be synthesized, we have devised an alternative strategy of ligation on Met32, utilizing homoCys as the ligating moiety and then alkylating the resulting polypeptide with methyl iodide. New conditions to quantitatively methylate thiol groups in complex polypeptides have been conceived, obtaining the protein in very good yields and purity. A CD spectroscopy investigation has revealed that the protein does not adopt canonical secondary structures but is very rich in β‐structure (∼ 60%), in agreement with a previous study carried out on samples obtained by recombinant methods. © 2006 Wiley Periodicals, Inc. Biopolymers 83: 508–518, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
The interplay of sequence and stereochemistry in defining conformation in proteins and polypeptides
Authors: Ranbhor Ranjit , Ramakrishnan Vibin , Kumar Anil , Durani Susheel
Published: August 2006

Sequential specification of conformation in proteins and polypeptides is a triangular interplay involving the system of linked peptides, the sequences in side chains, and water as solvent. Stereochemistry in side chain linkages is obviously important in the interaction between all of the players, but no specification of its explicit role, if any, in linking sequence with conformation has been made. Flory and coworkers made a puzzling observation in 1967 that, when mutated from poly‐L to alternating‐L,D stereochemical structure, polypeptides will suffer a reduction in overall dimension or characteristic ratio by an astonishing factor of 10 and to a value even lower than that predicted for free rotation (Miller, W. G.; Brant, D. A.; Flory, P. J. J Mol Biol 1967, 23, 67–80). Enquiring into this longstanding puzzle, Durani and coworkers found that the stereochemical modification will also abolish conformational sensitivity in polypeptide structure to solvent, because electrostatic interactions in the system of linked peptides are transformed from a condition of mutual conflict to one of harmony (Ramakrishnan, V.; Ranbhor, R.; Kumar, A.; Durani, S. J Phys Chem B 2006, 110, 9314–9323). Thus, poly‐L stereochemistry could be the fulcrum linking sequences with ϕ,ψs in protein and polypeptide structures, via dielectric arbitrations in a conflicting type of interpeptide electrostatics, in agreement with the electrostatic screening model of Avbelj and Moult (Avbelj, F.; Moult, J. Biochemistry 1995, 34, 755–764). © 2006 Wiley Periodicals, Inc. Biopolymers 83: 537–545, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Syntheses, Photophysical Properties, and Application of Through‐Bond Energy‐Transfer Cassettes for Biotechnology
Authors: Jiao Guan‐Sheng , Thoresen Lars H. , Kim Taeg Gyum , Haaland Wade C. , Gao Feng , Topp Michael R. , Hochstrasser Robin M. , Metzker Michael L. , Burgess Kevin
Published: August 2006

We have designed fluorescent “through‐bond energy‐transfer cassettes” that can harvest energy of a relatively short wavelength (e.g., 490 nm), and emit it at appreciably longer wavelengths without significant loss of intensity. Probes of this type could be particularly useful in biotechnology for multiplexing experiments in which several different outputs are to be observed from a single excitation source. Cassettes 1–4 were designed, prepared, and studied as model systems to achieve this end. They were synthesized through convergent routes that feature coupling of specially prepared fluorescein‐ and rhodamine‐derived fragments. The four cassettes were shown to emit strongly, with highly efficient energy transfer. Their emission maxima cover a broad range of wavelengths (broader than the four dye cassettes currently used for most high‐throughput DNA sequencing), and they exhibit faster energy‐transfer rates than a similar through‐space energy‐transfer cassette. Specifically, energy‐transfer rates in these cassettes is around 6–7 ps, in contrast to a similar through‐space energy‐transfer system shown to have a decay time of around 35 ps. Moreover, the cassettes are considerably more stable to photobleaching than fluorescein, even though they each contain fluorescein‐derived donors. This was confirmed by bulk fluorescent measurements, and in single‐molecule‐detection studies. Modification of a commercial automated DNA‐sequencing apparatus to detect the emissions of these four energy‐transfer cassettes enabled single‐color dye–primer sequencing.
Fest/Flüssig‐Trennung mit synthetischen und natürlichen Polymeren
Authors: Schwarz S. , Jaeger W. , Petzold G. , Bratskaya S. , Heinze T. , Liebert T. , Krentz O. , Kulicke W.‐M. , Paulke B.‐R.
Published: August 2006

Fest/Flüssig‐Trennprozesse sind sowohl in der Abwasserbehandlung als auch bei zahlreichen technischen Verfahren von wesentlicher Bedeutung. Die rationelle Durchführung von Koagulations‐, Flockungs‐ und Retentionsprozessen erfordert meist den Einsatz von Flockungsmitteln als Hilfsmittel. In diesem Beitrag wird über Flockungsergebnisse mit sowohl hydrophoben synthetischen Polyelektrolyten als auch neuen kationischen Stärkederivaten berichtet. Die gewählten Untersuchungsbedingungen ermöglichen dabei eine sehr gute Vergleichbarkeit der Resultate.
Neue Aspekte der Modellierung bei der Fluiddynamik von Packungskolonnen
Authors: Maćkowiak J.
Published: August 2006

In Anlehnung an das modifizierte Kanalmodell mit teils offener Umwandung und auf der Grundlage des Tropfen‐Schwebebettmodells (TSB‐Modell) wird eine neue Beziehung zur Bestimmung des Druckverlustes von unberieselten Schüttungen und Packungen bei der Einphasenströmung vorgestellt. An Beispielen wird gezeigt, dass es für geometrisch einfache Füllkörperformen möglich ist, ein allgemein gültiges Widerstandsgesetz für alle Füllkörperformen aufzustellen. Mit der neuen Gleichung kann man den die Form eines Füllkörpers kennzeichnenden Formfaktor ohne Experimente für eine ganze Reihe von bekannten Füllkörpern lediglich aus der Füllkörpergeometrie vorausberechnen, ohne Versuchsdaten auswerten zu müssen. Für komplizierte Füllkörperformen müssen jedoch zwecks Absicherung der Aussagen einige wenige Versuchsdaten zur Einphasenströmung an luftdurchströmten Füllkörperschüttungen oder Packungen vorliegen.
Dispergierscheiben, die bessere Alternative zum Hochdruck beim Emulgieren?
Authors: Urban K. , Wagner G. , Schaffner D. , Ulrich J.
Published: August 2006

Heutzutage finden Emulsionen eine breite Anwendung in der Industrie und im täglichen Leben. Neben Hochdruckemulgiersystemen stellen Dispergier‐/Dissolverscheiben eine einfache Möglichkeit dar, insbesondere hochviskose Emulsionen mit sehr langsamen Emulgatoren mit mittleren Tropfengrößen bis ca. 130 nm und engen Verteilungsbreiten zu erzeugen. Dabei sind sie vor allem kostengünstiger und bereiten weniger Probleme beim Scale up.
Verkokung und Koksabbrand in heterogenen Katalysatoren
Authors: Kern C. , Jess A.
Published: August 2006

Bei heterogen‐katalysierten Reaktionen mit organischen Einsatzstoffen kommt es häufig zu einer Deaktivierung der Katalysatoren durch die Bildung von Koksablagerungen. In der Praxis werden die verkokten Katalysatoren durch den Abbrand des Kokses mit Sauerstoff regeneriert und so die Aktivität der Katalysatoren wiederhergestellt. Auf dem Gebiet der Verkokung und des Koksabbrands ist in der Literatur eine Vielzahl von Forschungsarbeiten zu finden, die sich aber vornehmlich aus Sicht der Grundlagenforschung qualitativ mit dem Thema beschäftigen, also etwa mit Fragen der chemischen Struktur der Koksablagerungen. Der vorliegende Beitrag soll neben einem Überblick über diese Ergebnisse in erster Linie die Katalysatorregeneration durch den Koksabbrand sowohl im Einzelkorn als auch in einem Festbettreaktor näher beleuchten, da dieser Prozess bisher nur wenig Beachtung gefunden hat.
Isoperibole Kalorimetrie in der sicherheitstechnischen Praxis
Authors: Winkler S. , Lade M. , Vogel H.
Published: August 2006

In den Betrieben der chemischen Industrie werden zur Produktherstellung Stoffumwandlungen durchgeführt, die in den meisten Fällen unter Freisetzung von Wärme verlaufen. Somit nimmt die sicherheitstechnische Beurteilung von Reaktionen mit Hilfe der Kalorimetrie eine wichtige Rolle ein. Da während der Verfahrensentwicklung häufig nur geringe Probenmengen vorhanden sind, wird in diesem Beitrag ein isoperiboles Kalorimeter mit kleinem Reaktorvolumen und dessen Anwendung für unterschiedliche Reaktionstypen vorgestellt.
Einsatz und Potenzial der integrierten Miniplant‐Technologie für die Enzymkatalyse
Authors: Berendsen W. R. , Samorski M.
Published: August 2006

Die Kombination aus Miniplant‐Technik, Modellierung und Simulation, die auch als integrierte Miniplant‐Technologie bezeichnet wird, ist Stand der Technik in der chemischen Verfahrenstechnik. Sie bietet auch für die Verfahrensentwicklung enzymkatalysierter Reaktionen enorme Verbesserungspotenziale. Neben einer Übersicht über die Anwendungsgebiete der integrierten Miniplant‐Technologie wird der Nutzen für die enzymatische Reaktionstechnik anhand zweier Beispiele aus der aktuellen Forschung vorgestellt. Im ersten Beispiel werden die Erkenntnisse aus dieser Technologie zur Nachhaltigkeitsbewertung von Verfahrensalternativen genutzt. Das zweite Beispiel verdeutlicht, wie durch eine Rückkopplung von Miniplant‐Ergebnissen und ‐Simulationen sowohl eine Verbesserung des Biokatalysators als auch des Verfahrens erreicht werden kann.
Instationäre Betriebsweise zur Leistungssteigerung technischer Rieselbettreaktoren
Authors: Schubert M. , Bauer T. , Lange R.
Published: August 2006

Die Leistung und die Wirtschaftlichkeit stationär betriebener Rieselbettreaktoren werden hauptsächlich durch die Katalysatoreffektivität, den Druckverlust sowie die Gas/Flüssig‐Verteilung in der Katalysatorschüttung begrenzt. Zur Leistungssteigerung der Rieselbettreaktoren hat sich die instationäre Betriebsweise als eine geeignete Strategie herausgestellt. Diese Leistungssteigerung umfasst die Erhöhung von Umsatz, Selektivität und Produktivität. Zusätzlich kann die Reaktorsicherheit durch die gezielte Vermeidung von Hot Spots erhöht werden. Der Beitrag diskutiert den Stand der Technik einer instationären Betriebsweise und die Anwendungsmöglichkeiten bei technischen Rieselbettreaktoren.
Determination of the Bound Conformation of a Competitive Nanomolar Inhibitor of Mycobacterium tuberculosis Type II Dehydroquinase by NMR Spectroscopy
Authors: Prazeres Verónica F. V. , Sánchez‐Sixto Cristina , Castedo Luis , Canales Ángeles , Cañada Francisco Javier , Jiménez‐Barbero Jesús , Lamb Heather , Hawkins Alastair R. , González‐Bello Concepción
Published: August 2006

The synergy between tuberculosis and the AIDS epidemic, along with the surge of multidrug‐resistant isolates of M. tuberculosis, has reaffirmed tuberculosis as a primary public health threat. It is therefore necessary to discover new, safe, and more efficient antibiotics against this disease. On the other hand, mapping the dynamic interactions of inhibitors of a target protein can provide information for the development of more potent inhibitors and consequently, more potent potential drugs. In this context, the conformational binding of our previously reported nanomolar inhibitor of M. tuberculosis type II dehydroquinase, the 3‐nitrophenyl derivative 1, was studied using saturation transfer difference (STD) and transferred NOESY experiments. These studies have shown that in the bound state, one conformation of those present in solution of the competitive nanomolar inhibitor 3‐nitrophenyl derivative 1 is selected. In the bound conformation, the aromatic ring is slightly shifted from coplanarity, with the double bond and the nitro group of 1 oriented towards the double bond side.
Cover Picture: Automated Protein–Ligand Crystallography for Structure‐Based Drug Design (ChemMedChem 8/2006)
Authors: Mooij Wijnand T. M. , Hartshorn Michael J. , Tickle Ian J. , Sharff Andrew J. , Verdonk Marcel L. , Jhoti Harren
Published: August 2006

The cover picture shows a compound bound to thrombin, as determined by automated protein–ligand crystallography. The picture illustrates how a diffraction pattern can be automatically analysed to reveal the binding mode of a compound given a 2D chemical structure and a known 3D structure for the protein. The compound shown was developed by means of fragment‐based drug discovery, in which the binding of small, low‐affinity molecules is determined by crystallography. This approach to drug discovery is enabled by the automation of protein–ligand crystallography. For details, see the full paper by W. T. M. Mooij et al. on p. 827 ff.
Vinorelbine, doxorubicin, and prednisone in androgen‐independent prostate cancer
Authors: Borden Lester S. , Clark Peter E. , Lovato James , Hall M. Craig , Stindt Diana , Harmon Michele , M. Mohler Randi , Torti Frank M.
Published: August 2006

BACKGROUND.

Ultimately, patients with metastatic prostate cancer progress on androgen ablation therapy. The investigation of new chemotherapeutic regimens for the treatment of androgen‐independent prostate cancer (AIPC) is essential. The authors conducted a Phase II trial with vinorelbine, doxorubicin, and daily prednisone (NAP) to investigate the antitumor activity and palliative response of this regimen in patients with AIPC.

METHODS.

Forty‐six patients entered this Phase II combination chemotherapy trial. Patients were treated with both vinorelbine and doxorubicin at doses of 20 mg/m2 on Days 1, 8, and 15 every 28 days and prednisone 5 mg twice daily. Endpoints included prostate‐specific antigen (PSA) response and palliation, as measured by the Functional Assessment of Cancer Therapy‐Prostate (FACT‐P) instrument, the Brief Pain Inventory Scale, and a narcotic analgesic log.

RESULTS.

The median follow‐up for all 46 patients was 13.4 months. Fifty‐two percent of patients had impaired performance status at baseline. One responding patient remained on NAP and was progression‐free at 11.5 months. Thirty‐nine patients progressed, 3 patients died prior to response assessment, and 3 patients refused therapy. The median overall survival was 57 weeks (95% confidence interval [95% CI], 36–76 weeks), and the median time to disease progression was 17 weeks (range, 11–24 weeks). The PSA response among the 36 patients who completed 3 cycles of NAP was 42% (95% CI, 26–59%). There was a statistically significant improvement in quality of life measured both by the FACT‐General instrument (P = .03) and the FACT‐P instrument (P = .0006) over the 3 months compared with baseline measurements. Pain medicine use also improved: The median morphine equivalents among patients who were taking pain medications at the time of study enrollment showed a substantial decline after 1 cycle of treatment that was maintained. Pain (as assessed by the Brief Pain Inventory) improved compared with baseline pain at the 2nd‐month assessment (worst pain, P = .08; least pain, P = .02; and average pain, P = .003). Overall, the regimen was tolerated well. The most common side effects were mild fatigue and gastrointestinal complaints (all of which were Grade 1 or 2 [according to Version 2.0 of the Expanded Common Toxicity Criteria]). Seventeen patients (37%) experienced Grade 3 or 4 neutropenia. Five patients (11%) developed a cardiac ejection fraction of <50% during treatment and had doxorubicin discontinued. No patients developed clinical congestive heart failure.

CONCLUSIONS.

The NAP combination produced substantive palliation and a moderate response rate in men with AIPC. Cancer 2006. © American Cancer Society.
Theoretical Dynamic Studies on the Reaction of CH3C(O)CH3−nFn with the Hydroxyl Radical and the Chlorine Atom
Authors: Ji Yue‐Meng , Wang Li , Li Ze‐sheng , Liu Jing‐yao , Sun Chia‐chung
Published: August 2006

The mechanisms of the reactions: CH3C(O)CH2F+OH/Cl→products (R1/R2) and CH3C(O)CF3+OH/Cl→products (R3/R4) are studied over a wide temperature range (200–2000 K) by means of the dual‐level direct dynamics method. The optimized geometries and frequencies of the stationary points are calculated at the MP2/cc‐pVDZ and B3LYP/6‐311G(d,p) levels. The energy profiles of the reactions are then refined with the interpolated single‐point‐energy method (ISPE) at the BMC‐CCSD level. The canonical variational transition‐state theory (CVT) with the small‐curvature‐tunneling (SCT) correction method is used to calculate the rate constants. Using group‐balanced isodesmic reactions as working chemical reactions, the standard enthalpies of formation for CH3C(O)CH2F, CH3C(O)CF3, CH3C(O)CHF, CH2C(O)CH2F, and CH2C(O)CF3 are evaluated at the CCSD(T)/6‐311+G(2d,p)//MP2/cc‐pVDZ level of theory. The results indicate that the hydrogen abstraction is dominated by removal from the fluoromethyl position rather than from the methyl position.
A Theoretical Study of the Mechanism and Kinetics of F+N3 Reactions
Authors: Ma Haitao , Liu Xiaojun , Bian Wensheng , Meng Lingpeng , Zheng Shijun
Published: August 2006

Both the singlet(1A′) and triplet(3A′′) potential energy surfaces (PESs) of F+N3 reactions are investigated using the complete‐active‐space self‐consistent field (CASSCF) and the multireference configuration interaction (MRCI) methods with a proper active space. The minimum energy crossing point (MECP) at the intersection seam between the 1A′ and 3A′′ PESs is located and used to clarify the reaction mechanisms. Two triplet transition states are found, with one in the cis form and the other one in the trans form. Further kinetic calculations are performed with the canonical unified statistical (CUS) theory on the singlet PES and the improved canonical variational transition‐state (ICVT) method on the triplet PES. The rate constants are also reported. At 298 K, the calculated rate constant is in reasonably good agreement with experimental values, and spin–orbit coupling effects lower it by 28 %. The spectroscopic constants derived from the fitted potential‐energy curves for the singlet and triplet states of NF are in very good agreement with experimental values. Our calculations indicate that the adiabatic reaction on the singlet PES leading to NF(a1Δ)+N2 is the major channel, whereas the nonadiabatic reaction through the MECP, which leads to NF(X3Σ−)+N2, is a minor channel.
Cover Picture: Glass Bead Probes of Local Structural and Mechanical Properties of Fluid, Supported Membranes (ChemPhysChem 8/2006)
Authors: Dixit Sanhita S. , Szmodis Alan , Parikh Atul N.
Published: August 2006

The cover picture shows a spatial pattern of morphology‐dependent elastic response of supported membranes to gravitationally settled microscopic glass beads. Beads differentiate lipid monolayers (red regions) from fluid bilayers (yellow regions) by inducing a qualitatively different elastic response, characterized by nondeformed binding for lipid monolayers (uncoated beads) and a wetting or membrane wrapping for bilayers (membrane wrap enveloping the beads). These results presented by Parikh et al. on page 1678 indicate the importance of interleaflet coupling and bilayer fluidity in determining elastic response of supported membranes. They also suggest a new, simple technique to probe mechanical properties of substrate‐supported fluid membranes. The art work was designed by James Evans.
Exact elliptic compactons in generalized Korteweg–De Vries equations
Authors: Cooper Fred , Khare Avinash , Saxena Avadh
Published: August 2006

Using the action principle, and assuming a solitary wave of the generic form u(x,t) = AZ(β(x + q(t)), we derive a general theorem relating the energy, momentum, and velocity of any solitary wave solution of the generalized Korteweg‐De Vries equation K*(l,p). Specifically we find that
${\dot q}=r(l,p)H/P$, where l,p are nonlinearity parameters. We also relate the amplitude, width, and momentum to the velocity of these solutions. We obtain the general condition for linear and Lyapunov stability. We then obtain a two‐parameter family of exact solutions to these equations, which include elliptic and hyper‐elliptic compacton solutions. For this general family we explicitly verify both the theorem and the stability criteria. © 2006 Wiley Periodicals, Inc. Complexity 11: 30–34, 2006
Co‐existence of Poisson and non‐Poisson processes in ordered parallel multilane pedestrian traffic
Authors: Bantang Johnrob , Saloma Caesar
Published: August 2006

We show that non‐Poisson and Poisson processes can coexist in ordered parallel multilane pedestrian traffic, in the presence of lane switching which asymmetrically benefits the switchers and nonswitchers. Pedestrians join at the tail end of a queue and transact at the opposite front end. Their aim is to complete a transaction within the shortest possible time, and they can transfer to a shorter queue with probability ps. Traffic is described by the utilization parameter U = λ〈ts〉/N, where λ is the average rate of pedestrians entering the system, 〈ts〉 is the average transaction time, and N is the number of lanes. Using an agent‐based model, we investigate the dependence of the average completion time 〈tc〉 with variable K = 1 + (1 − U)−1 for different N and 〈ts〉 values. In the absence of switching (ps = 0), we found that 〈tc〉 ∝ Kτ, where τ ≈ 1 regardless of N and 〈ts〉. Lane switching (ps = 1) reduces 〈tc〉 for a given K, but its characteristic dependence with K differs for nonswitchers and switchers in the same traffic system. For the nonswitchers, 〈tc〉 ∝ Kτ, where τ < 1. At low K values, switchers have a larger 〈tc〉 that also increases more rapidly with K. At large K, the increase rates become equal for both. For nonswitchers, the possible tc values obey an exponentially decaying probability density function p(tc). The switchers on the other hand, are described by a fat‐tailed p(tc) implying that a few are penalized with tc values that are considerably longer than any of those experienced by nonswitchers. © 2006 Wiley Periodicals, Inc. Complexity 11: 35–42, 2006
Social percolation in relations between activists and supporters
Authors: Takahashi Kazuyuki Ikko , Murai Ryousuke
Published: August 2006

This article is a study of the relations between activists with a strong belief and their passive supporters. In order to achieve a fuller understanding of these relations the authors make use of bond percolation theory. The theories hold that when the size of a group's communication in a given society exceeds a critical threshold; that is, when the size of the cluster of supporters' bonds becomes practically infinite within the society by virtue of the work of activists, subsequently supporters and activists come to hold key positions in society. A graph is generated indicating the probability of activists' bonds with respect to the probability of supporters' bonds within a lattice, when the biggest cluster of supporters' bonds becomes infinite. Simulations have been undertaken, and when a case is found in which infinite clusters emerge, this value of the probability of both supporters' and activists' bonds is isolated. A graph can then be generated a graph on which to plot these values as points. After that, these results can be discussed at length and some conclusions are derived from them. © 2006 Wiley Periodicals, Inc. Complexity 11: 51–56, 2006
Quantitative assessment of right and left reaching movements in infants: A longitudinal study from 6 to 36 months
Authors: Rönnqvist Louise , Domellöf Erik
Published: August 2006

This longitudinal study aimed to explore the early presence and developmental pattern of laterality in reaching kinematics and its relationship to side use. In order to do so, 3‐D kinematic measurements as well as 2‐D video recordings of right‐left reaching movements were successively carried out for 17 infants at the ages of 6, 9, 12, and 36 months. Additional investigations of hand preference were made at 36 months. As four infants were prematurely born, their outcomes were compared to those of the fullterm participants. While most of the infants in the early ages showed a rather inconsistent preference in terms of frequency and distributions of right‐left side use, the analyses of reaching kinematics revealed a more consistent pattern of fewer movements units (MUs) and straighter right‐sided reaching for the majority of infants at all tested ages. However, reaching kinematics from the preterm infants were generally more variable and less side consistent. It is proposed that the development of human handedness originates from an early right arm rather than hand preference in that representations of asymmetry in bilateral projections (involved in arm movements) developmentally precede contralateral projections (involved in refined hand/finger movements). © 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 444–459, 2006.
Agenesis of the corpus callosum and the establishment of handedness
Authors: Sacco Silvia , Moutard Marie‐Laure , Fagard Jacqueline
Published: August 2006

The goal of this study was to check whether an isolated agenesis of the corpus callosum, detected in utero with ultrasound recording, would impair the early development of unimanual and bimanual handedness. Twelve infants with isolated agenesis of the corpus callosum, either total (TACC) or partial (PACC) were tested for handedness at the end of their first year, and were compared to infants with typical development (TD), matched for age and sex. A majority of infants showed right‐handedness at the unimanual grasping tasks, with no significant difference between the TD and ACC groups. When the object was presented to the left, the TACC infants were more likely to grasp the object with their right hand (with or without the left hand) than both the TD and the PACC infants who used mostly the ipsilateral left hand. The only significant difference between TD and ACC infants concerned bimanual coordination, as less ACC infants (especially TACC) succeeded at the bimanual task, compared with TD infants. In addition, the strategy of the former tended to be less right‐handed than that of the latter. Our results confirm the role of the CC in bimanual coordination, indicating that the early emergence of bimanual coordination and, if confirmed, bimanual handedness, are likely to be delayed in the absence of corpus callosum, especially if agenesis is total. They do not support the idea that the CC is necessary for the early onset of handedness. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 472–481, 2006.
Laterality in persons with intellectual disability II. Hand, foot, ear, and eye laterality in persons with Trisomy 21 and Williams‐Beuren syndrome
Authors: Gérard‐Desplanches Aude , Deruelle Christine , Stefanini Silvia , Ayoun Catherine , Volterra Virginia , Vicari Stefano , Fisch Gene , Carlier Michèle
Published: August 2006

Laterality (hand, foot, ear, and eye) was assessed in participants with Trisomy 21 (62) and Williams–Beuren syndrome (WBS) (39). Handedness was also assessed in a card reaching task. The comparison group included 184 typically developing persons. Two independent age sub‐groups were formed: 7 to 10 years old and 11 to 34 years old. We confirmed previous data: individuals with T21 were more frequently left‐ or mixed‐handed than typically developing persons; individuals with WBS had intermediate scores. The two groups with genetic disorders had less right foot preference. Manual and foot inconsistencies characterized both groups with genetic disorders. Cross hand–foot preference was lower in the typically developing group. Differences in IQ levels did not correlate with differences in laterality scores. Overall laterality profiles were not the same in the two groups with genetic disorders: the greatest differences were observed between typically developing persons and persons with Trisomy 21. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 482–491, 2006.
Parental and perinatal factors influencing the development of handedness in captive chimpanzees
Authors: Hopkins William D. , Wesley Michael J. , Russell Jamie L. , Schapiro Steven J.
Published: August 2006

It has been proposed that human right handedness is determined by genetic factors associated with the emergence of language, whereas non‐human primate handedness is determined by random, non‐genetic factors. These different mechanisms account for differences in the distribution of handedness between human and non‐human primates. Here we report evidence that genetic factors play a role in the determination of handedness in chimpanzees. We further report that differential rearing has no influence on the expression of handedness in related individuals. Contrary to many theories of the origin of handedness, these results indicate that genetic factors have a significant influence on handedness in chimpanzees. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 428–435, 2006.
Dyslexia at a behavioural and a cognitive level
Authors: Helland Turid
Published: August 2006

The aim of this study was to see whether patterns of neuro‐cognitive assets and deficits seen in dyslexia also would lead to different patterns of reading and writing. A group of dyslexic children was subgrouped by language comprehension and mathematics skills in accordance with the definition of the British Dyslexia Association of 1998. This yielded three subgroups that showed three distinct neuro‐cognitive profiles depicted within the Multi‐Component Model of Working Memory. The participants were tested with single word reading and spelling tasks. The scores varied only to a minor degree between the subgroups. The results were discussed in view of developmental phases into literacy. Only one subgroup could be defined within the orthographic phase, while the other two were within the alphabetic phase. Thus, patterns at the neuro‐cognitive level seen in the subgroups were to a limited degree reflected at the behavioural level. The results were also discussed in view of different orthographies. Since using information from phonological testing only, as currently appears to be common practice in many contexts, may result in intervention with little effect for some dyslexics, it was concluded that assessing neuro‐cognitive assets and deficits targeting dyslexia is essential to intervention and the understanding of dyslexia. Copyright © 2006 John Wiley & Sons, Ltd.
Language‐related differences between discrepancy‐defined and non‐discrepancy‐defined poor readers: a longitudinal study of dyslexia in New Zealand
Authors: Tunmer William E. , Chapman James W.
Published: August 2006

Language‐related differences between discrepancy‐defined and non‐discrepancy‐defined poor readers were examined in a three‐year longitudinal study that began at school entry. The discrepancy‐defined (dyslexic) poor readers (n = 19) were identified in terms of poor reading comprehension and average or above average listening comprehension performance, and the non‐discrepancy‐defined (non‐dyslexic) poor readers (n = 19) in terms of both poor reading and listening comprehension performance. The two poor reader groups and a group of normally developing readers (n = 55) were given several oral language, phonological processing, and reading performance measures at six testing occasions. Results indicated that in addition to expected differences on the oral language measures, the non‐discrepancy‐defined poor readers also showed greater phonological processing deficits than the dyslexic poor readers. The results are discussed in terms of the lack of official recognition of dyslexia in New Zealand, the whole language orientation of classroom reading instruction, and the inadequacy of Reading Recovery for minimizing reading problems. Copyright © 2006 John Wiley & Sons, Ltd.
La17Si9Al4N32–xOx (x ≤ 1): A Nitridoaluminosilicate with Isolated Si/Al‐N/O Clusters
Authors: Pilet Guillaume , Grins Jekabs , Edén Mattias , Esmaeilzadeh Saeid
Published: August 2006

A nitrogen‐rich aluminosilicate with nominal composition La17Si9Al4N33 has been synthesised at 1500–1650 °C under a N2 atmosphere by reaction of La metal, AlN and Si3N4. Its crystal structure was solved and refined in space group F3m, with a = 15.4279(6) Å and Z = 4, to Rf = 1.9 %. The structure contains two novel types of discrete tetrahedral aluminosilicate clusters, with respective nominal compositions Al4Si4N17 and Si5N16, with La atoms in between. Bulk samples were also investigated by powder X‐ray and electron diffraction. The 29Si and 27Al solid‐state NMR results indicate that the phase contains minor amounts of oxygen and has a narrow compositional range with probable end limits La17Si9Al4N33 and La16.67Si9Al4N32O.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Electroluminescence Properties of fac‐Tris(2‐phenylpyridine)iridium Derivatives Containing Hole‐Trapping Moieties
Authors: Ono Katsuhiko , Joho Michitoshi , Saito Katsuhiro , Tomura Masaaki , Matsushita Yosuke , Naka Shigeki , Okada Hiroyuki , Onnagawa Hiroyoshi
Published: August 2006

In order to investigate an effective method for carrier injection into the phosphor of organic electroluminescent (EL)devices, we synthesized fac‐tris(2‐phenylpyridine)iridium [Ir(ppy)3] derivatives containing hole‐trapping moieties, such as diphenylamine, carbazole, and phenoxazine. Their photoluminescent maxima were observed around the maximum of Ir(ppy)3. These values were slightly shifted depending on the hole‐trapping moieties: redshifted due to diphenylamine and blueshifted due to carbazole and phenoxazine. Further, these moieties affected the oxidation potentials of Ir complexes in cyclic voltammetry. EL devices using an Ir complex with diphenylamine exhibited high EL performance because 1,1‐bis[4‐(di‐p‐tolylamino)phenyl]cyclohexane (TAPC) was employed as a hole‐transporting layer. The maximum external quantum efficiency (ηext) was recorded as 12.2 %. This value is comparable to that observed in a device using Ir(ppy)3. These results indicate that the diphenylamino substituent is favorable to serve as a hole‐trapping moiety of Ir(ppy)3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Galactose Oxidase Models: Creation and Modification of Proton Transfer Coupled to Copper(II) Coordination Processes in Pro‐Phenoxyl Ligands
Authors: Michel Fabien , Thomas Fabrice , Hamman Sylvain , Philouze Christian , Saint‐Aman Eric , Pierre Jean‐Louis
Published: August 2006

Two tripodal ligands containing two pyridyl and one 4‐(benzimidazol‐2‐yl)‐2‐tert‐butylphenol (HLH) and one 2‐tert‐butyl‐4‐(N‐methylbenzimidazol‐2‐yl)phenol (HLMe) unit have been synthesized. They possess a N3O donor set that is known to stabilize phenoxyl radicals more efficiently than the corresponding N2O2 donor unit. Reaction of one molar equiv. of Cu(ClO4)2·6H2O with HLH or HLMe affords the zwitterionic benzimidazolium phenolate complexes [CuII(HLH)]2+ and [CuII(HLMe)]2+ via a proton transfer reaction coupled to copper(II) coordination. Addition of HClO4 to [CuII(HLH)]2+ and [CuII(HLMe)]2+ results in the formation of the benzimidazolium phenol complexes [CuII(H2LH)]3+ and [CuII(H2LMe)]2+, while addition of NEt3 affords the benzimidazol‐phenolate complexes [CuII(LH)]2+ and [CuII(LMe)]2+, respectively. The phenol’s pKa is remarkably low due to the strong withdrawing effect of the benzimidazolium substituent. X‐ray crystallographic analysis of the copper(II) complexes shows that deprotonation of the axial phenol forces the metal to move out of the square plane towards the oxygen atom, and one (or two) Cu–Npyridine equatorial bond length increases. The copper(II) phenoxyl species [CuII(HLH)]·3+ and [CuII(HLMe)]·3+ were prepared electrochemically, or by addition of two molar equiv. of copper(II) to HLH or HLMe. Under these conditions, radical formation has never been observed for tripodal ligands containing two pyridyl and one 2,4‐di‐tert‐butylphenol group. This difference is explained in terms of the proton transfer mechanism and redox potentials. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Ferrocenes Bearing Sulfinylamino Groups
Authors: Wrackmeyer Bernd , Klimkina Elena V. , Milius Wolfgang , Siebenbürger Miriam , Tok Oleg L. , Herberhold Max
Published: August 2006

1,1′‐Diaminoferrocene (2) and 1,1′‐bis(trimethylsilylamino)ferrocene (3) have been converted into sulfinylamines by treatment with thionyl chloride in the presence of triethylamine. In the case of 2 the 1:2 reaction affords 1,1′‐bis(sulfinylamino)ferrocene (5) and the 1:1 reaction gives 6‐amino‐1‐sulfinylaminoferrocene (6). Bis(trimethylsilylamino)ferrocene reacts with thionyl chloride in a 1:1 molar ratio to give 1‐sulfinylamino‐6‐(trimethylsilylamino)ferrocene (8). In contrast, the reaction of N,N′‐dilithiobis(trimethylsilylamino)ferrocene (4) with thionyl chloride gives the [3]ferrocenophane 9, which contains an N–S(O)–N bridge, rather than sulfinylamines or a sulfur diimide. The molecular structures of 5 and 8 were determined by X‐ray analysis. The 57Fe NMR chemical shift (δ = +2597.0 ppm) for 5 indicates the strong π‐acceptor properties of the NSO groups. Dynamic 1H and 13C NMR spectra prove the hindered rotation of the NSO group about the C–N bonds in 5, 6 and 8. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
CoIII Complexes with Square‐Planar N2S2‐ and N2(SO2)2‐Type Ligands as An Active Site Structural Model for Nitrile Hydratase – Biological Implications of an Amidate Coordination
Authors: Yano Takuma , Arii Hidekazu , Yamaguchi Syuhei , Funahashi Yasuhiro , Jitsukawa Koichiro , Ozawa Tomohiro , Masuda Hideki
Published: August 2006

In an attempt to understand the unique active site structure of nitrile hydratase, four CoIII complexes with square‐planar N2S2‐ or N2(SO2)2‐type donor sets, Na[CoIII(L:N2S2)] (1‐Na), PPh4[CoIII(L:N2S2)] (1‐PPh4), PPh4[CoIII(L:N2S2)(tBuNC)2] (2), and PPh4[CoIII{L:N2(SO2)2}(tBuNC)2] (3) were synthesized and characterized on the basis of electronic absorption spectroscopy, IR spectroscopy, cyclic voltammetry, and X‐ray structural analysis. Both of the crystal structures of complexes 1‐Na and 1‐PPh4 revealed a square planar structure with N2S2 donating atoms, and 2 exhibited an octahedral structure coordinated with two tert‐butylisocyanide (tBuNC) molecules at the axial sites of complex 1‐PPh4. Complex 3, which showed an octahedral structure with sulfinate sulfur atoms equatorially coordinated to the center, was synthesized by the treatment of 2 with a suitable oxidant. The reduction potential values from CoIII to CoII for complex 3 in solution demonstrated a larger positive shift when compared with those of complexes 1‐PPh4 and 2, which indicates that the oxygenation of the sulfur atoms increased the Lewis acidity of the CoIII center. Interestingly, the coordination equilibrium, the C=O stretching frequency, and the redox potential for 1‐PPh4 were all closely related to the acceptor number (AN) of the solvents. Furthermore, the coordination of monodentate tBuNC to the axial position of 1‐PPh4 was dependent on the solvents used. These findings indicate that an electrophilic interaction between the carbonyl oxygen atoms and the solvent molecules control the Lewis acidity of the metal ion. On the other hand, such a solvent dependence was not detected in the S=O stretching frequency of sulfinates 3. We have concluded that the increase in the redox potential/Lewis acidity of the metal center is a result of the oxygenation of sulfur, and that this increase is controlled by the interaction of the amidate carbonyl oxygen with the secondary coordination sphere. As demonstrated in previous mutation studies, this study suggests that the interaction of the nitrile hydratase active site with the functional groups from the peptide backbone is essential for the catalytic activity of the complex. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Quantitative Removal of Mercury(II) from Water Through Bulk Liquid Membranes by Lipophilic Polyamines
Authors: Spreti Nicoletta , Brinchi Lucia , Germani Raimondo , Vincenza Mancini Maria , Savelli Gianfranco
Published: August 2006

Transport of mercury(II) and copper(II) ions through bulk liquid membranes has been studied, the former because of its toxicity and wide distribution in the environment, the latter for comparative purposes. The abilities of two carriers, the known N,N′‐bis[2‐(hexadecylamino)ethyl]‐N,N′‐bis(hydroxyethyl)ethylenediamine (bis‐HE16ED) and the new N,N′‐bis(p‐octyloxybenzyl)‐3,6‐dioxaoctane‐1,8‐diamine (bis‐pODODA), to complex and transport the selected metal ions are reported. Bis‐HE16ED is a good carrier for Cu2+ ions, but the high stability of the carrier/Hg2+ ion complex in the membrane results in a lack of its transport. On the other hand, the new carrier displays a very high efficiency in Hg2+ ion transport, effecting quantitative transfer of the metal ion into the receiving phase within 24 h, despite its chelating region being only slightly different from that in bis‐HE16ED. The ability of bis‐pODODA to transport 100 % of Hg2+ efficiently in consecutive cycles is also reported. This result provides a basis for future development of a decontamination process based on a carrier‐mediated transport system. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Asymmetric Ring‐Opening of Epoxides and Aziridines with Carbon Nucleophiles
Authors: Pineschi Mauro
Published: August 2006

Three‐membered heterocyclic rings offer a powerful combination of reactivity, stability, availability, and atom economy. While heteroatom‐based nucleophiles have been successfully employed, the use of carbon‐centered nucleophiles is much less developed, yet represents a significant advance since it builds the basic carbon framework. In fact, the asymmetric ring‐opening of epoxides and aziridines with carbon‐based nucleophiles, as will be discussed in this Microreview, offers the possibility of generating valuable, chiral, nonracemic building blocks in a very simple, stereodefined manner. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Conformational Properties of Partially Alkylated Methylene‐Bridged Resorc[4]arenes – Study of the “Flip‐Flop” Inversion
Authors: Dvořáková Hana , Štursa Jan , Čajan Michal , Moravcová Jitka
Published: August 2006

The deprotection of resorc[4]arene octaisopropyl ether 5 by boron trichloride in dichloromethane has been found to give a parent resorc[4]arene, 1, as well as a mixture of partially alkylated derivatives, 6, 7, 8 and 9, the ratio of which depended on the conditions used. The conformational behaviour of the prepared alkyl ethers was studied with temperature‐dependent 1H NMR spectroscopy and quantum chemical calculations. It was found that the compounds 6, 7 and 8 interconvert between two possible identical crown conformations (flip‐flop inversion). The activation free energy ΔG‡ values for this process, obtained by NMR, strongly depends on the number of hydroxy groups in the molecule; an increase in their number generally increases the values of ΔG‡. The flip‐flop inversion was not observed in the cases of fully deprotected 1 and monoisopropyl resorc[4]arenes 9, which are soluble only in polar solvents, inconvenient for the formation of a hydrogen bonding system. Molecular modelling studies revealed that the flip‐flop inversion proceeds via the consecutive rotation of two adjacent rings, leading to a transition state with deformed chair geometry. Subsequent rotation of the remaining two units leads to the formation of the second crown conformer. The calculated heights of the energy barriers correspond well with those obtained by NMR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Life cycle impact assessment of various treatment scenarios for sulfur hexafluoride (SF6) used as an insulating gas
Authors: Shiojiri K. , Yamasaki A. , Fujii M. , Kiyono F. , Yanagisawa Y.
Published: August 2006

A life cycle environmental impact assessment was conducted for sulfur hexafluoride (SF6) used as an insulating gas in electrical devices. Eight scenarios with a variety of SF6 treatment processes were considered. For each scenario, the life cycle power consumption was determined and an inventory analysis of pollutants and toxic materials was conducted. The scenarios were compared in terms of their life cycle environmental impacts, such as power consumption, global warming, acidification, eutrophication, generation of photochemical oxidants, and generation of substances toxic to human health. The power consumption is significantly reduced by the use of a gaseous mixture of SF6 and nitrogen in comparison to when pure SF6 is used, because the power consumption required for producing SF6, which is the major power consumption process, can be reduced according to the amount of SF6 replaced by nitrogen. On the other hand, larger amounts of the pollutants associated with the transportation process will be generated for the scenarios using gaseous mixtures with smaller SF6 contents in the insulating gas. The reuse of spent SF6 after purification can also reduce the power consumption. The calculated environmental impacts were unified with two types of environmental indexes using Eco‐Indicator 99 and LIME (Life‐cycle Impact assessment Method based on Endpoint modeling), and the scenarios were evaluated and compared. © 2006 American Institute of Chemical Engineers Environ Prog, 2006