bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly Crystalline Polyaniline Nanostructures Doped with Dicarboxylic Acids
Authors: Zhang Z. , Wan M. , Wei Y.
Published: April 2006

Highly crystalline polyaniline (PANI) nanotubes and nanofibers ca. 80–170 nm in diameter are successfully prepared by a “micelle soft‐template” method in the presence of dicarboxylic acids dopants with different numbers (n) of –CH2– groups (n = 0–4). It is found that the diameter of the nanostructures increases on increasing the number of –CH2– groups in the dicarboxylic acids. The conductivity of the nanostructures increases as their diameters decrease, showing that size has an effect on conductivity. A narrow peak at 2θ = 6.50° is observed in the X‐ray diffraction pattern, indicating that the distance in the direction perpendicular to the polymer chain increases as the number of –CH2– groups increases.
Thermal decomposition of carbon dioxide coupled with POM in a membrane reactor
Authors: Jin Wanqin , Zhang Chun , Zhang Peng , Fan Yiqun , Xu Nanping
Published: April 2006

In this study, we proposed coupling the thermal decomposition of carbon dioxide (CO2 → CO + 1/2O2) with the partial oxidation of methane (POM) to syngas (CH4 + 1/2O2 → CO + 2H2) in a dense mixed‐conducting membrane reactor, in which the reaction of CO2 decomposition took place in one side of the membrane and the POM reaction occurred in the other side of the membrane simultaneously (or methane reacted with oxygen that was permeated through the membrane from the CO2 decomposition, to produce H2 and CO over supported transition metal catalysts). A perovskite‐type oxygen‐permeable membrane of SrCo0.4Fe0.5Zr0.1O3‐δ (SCFZ) was used for the membrane reactor. The effects of temperature and the feed flow rates of CO2 and CH4 on the reaction performance of the SCFZ membrane reactor were investigated. It was found that the CO2 conversion increased with increasing the temperature and decreased with increasing the feed flow rates of CO2 or with decreasing the feed flow rates of CH4. At 1173 K, the CO2 conversion reached about 11.1%, and the CH4 conversion, CO selectivity, and the ratio of H2/CO were 84.5%, 93%, and 1.8, respectively. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Ontogeny of facial dimorphism and patterns of individual development within one human population
Authors: Bulygina E. , Mitteroecker P. , Aiello L.
Published: April 2006

Based on a longitudinal study of radiographs of the Denver Growth Study, we investigated the morphological development of individual and gender differences in the anterior neurocranium, face, and basicranium. In total, 500 X‐rays of 14 males and 14 females, each with 18 landmarks and semilandmarks, were digitized and analyzed using geometric morphometric methods. Sexual dimorphism in shape and form is already present at the earliest age stage included in the analysis. However, the nature of dimorphism changes with age. Four factors apper to contribute to cranial sexual dimorphism in human postnatal development: 1) initial, possibly prenatal, differences in shape; 2) differences in the association of size and shape; 3) male hypermorphosis; and 4) some degree of difference in the direction of male and female growth trajectories. Studying changes in individuals, we find a low correlation between newborn and adult morphology, while 3‐year‐olds already show a high correlation with their adult form. We conclude that the adult pattern of interindividual difference in facial form in a single human population is established within the first few years of life. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.
Continuity of interpersonal violence between Nubian communities
Authors: Judd Margaret A.
Published: April 2006

Modern communities affiliated with the same culture have been shown to experience comparable levels of interpersonal violence, no matter what their size. It was hypothesized that a similar relationship would exist among ancient rural and urban people, but that accident‐related trauma may be more prominent among rural dwellers due to their activity base. Through an analysis of antemortem trauma, this investigation contrasted the injury profile of Nubian adult villagers (N = 55) from the Kerma period (2500–1750 BC) to that of their urban neighbors (N = 223) at Kerma (2050–1500 BC). The injury pattern associated with interpersonal violence (cranial injury, direct‐force ulna fractures, and multiple injuries) was similar between the two samples, as hypothesized. The rural group sustained significantly more nonviolence‐related injuries that suggested occupational or environmental influences. The more severe cranial injuries observed among urban people are attributed to a preference for more lethal hand‐wielded objects that may have accompanied increasing local tensions and incursions into Egypt during the 17th Dynasty. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.
Brief communication: Identification of the authentic ancient DNA sequence in a human bone contaminated with modern DNA
Authors: Bouwman Abigail S. , Chilvers Elizabeth R. , Brown Keri A. , Brown Terence A.
Published: April 2006

We present a method to distinguish authentic ancient DNA from contaminating DNA in a human bone. This is achieved by taking account of the spatial distribution of the various sequence families within the bone and the extent of degradation of the template DNAs, as revealed by the error content of the sequences. To demonstrate the veracity of the method, we handled two ancient human tibiae in order to contaminate them with modern DNA, and then subjected segments of the bones to various decontaminating treatments, including removal of the outer 1–2 mm, before extracting DNA, cloning, and obtaining a total of 107 mitochondrial DNA sequences. Sequences resulting from the deliberate contamination were located exclusively in the outer 1–2 mm of the bones, and only one of these 27 sequences contained an error that could be ascribed to DNA degradation. A second, much smaller set of relatively error‐free sequences, which we ascribe to contamination during excavation or curation, was also located exclusively in the outer 1–2 mm. In contrast, a family of 72 sequences, displaying extensive degradation products but identifiable as haplogroup U5a1a, was distributed throughout one of the bones and represents the authentic ancient DNA content of this specimen. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.
Tetracyanethylen: die charakteristischen Geometrien und Schwingungsabsorptionen seiner zahlreichen Strukturen
Authors: Miller Joel S.
Published: April 2006

Tetracyanethylen, TCNE, geht zahlreiche chemische Reaktionen ein, und in der Literatur werden für diese Verbindung viele Strukturmotive beschrieben, deren Identifizierung oft schwierig ist. Die Zahl der $\tilde \nu $CN‐Absorptionen und die dazugehörigen Wellenzahlen geben einen Einblick in die jeweilige Struktur und Ladung des TCNE‐Fragments. Besonders die Mittelwerte der Wellenzahlen der fundamentalen νCN‐Schwingungen und die Länge der zentralen C‐C‐Bindung liefern wichtige Informationen. In diesem Aufsatz diskutieren wir die Bestimmung von Struktur und Formalladung von TCNE‐Fragmenten. Wir diskutieren Unstimmigkeiten, die sich bei Überprüfung älterer Strukturzuordnungen ergeben, und liefern eine Grundlage für zukünftige Untersuchungen der Struktur‐Eigenschafts‐Beziehungen von TCNE. Viele Komplexe mit verbrückendem [TCNE]z zeigen gemischte Valenz und ausgeprägte Delokalisierung. Der Mangel an geeigneten Modellverbindungen, besonders solchen mit M‐Rückbindung zu den CN‐Gruppen, hat bisher eine detaillierte Beschreibung dieser gemischtvalenten Verbindungen verhindert. Hierfür werden neue, gut charakterisierte mehrkernige Verbindungen benötigt.
Titelbild: Synthesis and Characterization of a Multicomponent Rhenium(I) Complex for Application as an OLED Dopant (Angew. Chem. 16/2006)
Authors: Lundin Natasha J. , Blackman Allan G. , Gordon Keith C. , Officer David L.
Published: April 2006

Modulare Moleküle als effiziente Dotierungen für organische Leuchtdioden (OLEDs) erleichtern den gerichteten Transport von Elektronen und Löchern, der zu deren Rekombination im emittierenden Zentrum führt. K. C. Gordon et al. stellen in ihrer Zuschrift auf S. 2644 ff. einen phosphoreszierenden Farbstoff vor, in dem das emittierende Zentrum auf einer Seite an eine Elektronentransportgruppe und auf der anderen an eine Lochtransportgruppe gebunden ist (siehe Titelbild).
Experimentelle Bestimmung der hygrischen Sorptionsisotherme und des Feuchtetransportes unter instationären Bedingungen
Authors: Plagge Rudolf , Funk Max , Scheffler Gregor , Grunewald John
Published: April 2006

Mit der vorgestellten Augenblicksprofil‐Methode (APM) werden sowohl die relative Luftfeuchte und die Temperatur, als auch der volumetrische Wassergehalt in bestimmten Positionen in einem porösen Material bestimmt. Die Messungen werden kontinuierlich unter instationären Bedingungen durchgeführt. Damit erlaubt die APM eine dynamische und gleichzeitige Messung der hygroskopischen Sorptionsisotherme und der hygrischen Feuchteleitfähigkeit für einzelne Kompartimente innerhalb der Materialprobe. Die Feuchteleitfähigkeit wird aus den sich zeitlich ändernden Potentialgradienten und den dazugehörigen Feuchteverteilungen für die jeweiligen Kompartimente berechnet.

Die Anwendung nicht konstanter Randbedingungen in der APM erlaubt die Untersuchung des hygrodynamischen Verhaltes von porösen Materialien. In der vorliegenden Studie werden die zeit‐ und prozeßabhängige Feuchtespeicherung und der Feuchtetransport bestimmt.

Die vorgestellten Adsorptions‐ und Desorptionsexperimente wurden an dem kapillar‐ aktiven Wärmedämmstoff Calciumsilikat durchgeführt. Die Ergebnisse geben das Hystereseverhalten und den Einfluß der Dynamik der Prozesse wider. In Positionen mit schnellen Feuchteänderungen wird die Feuchtespeicherfunktion im Vergleich mit Regionen langsamer Feuchteänderung nach oben verschoben. Die Feuchteleitfähigkeit als Funktion der relativen Luftfeuchte zeigt eine bedeutende Hysterese. Hingegen ist die Feuchteleitfähigkeit in Relation zum Wassergehalt nicht hysteretisch. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rechnerische Bewertung von Trocknungsverfahren für hochwassergeschädigtes Mauerwerk
Authors: Grunewald John , Plagge Rudolf
Published: April 2006

Überschwemmungen sind ein globales Phänomen, was durch die jüngsten Ereignisse in Zentral‐ und Nordeuropa wieder bestätigt wurde. Die Fluten hinterlassen beträchtliche Schäden an Gebäuden und beeinträchtigen das menschliche Zusammenleben. Sind Schäden an Einrichtungen zu verzeichnen, stehen staatliche Institutionen, Versicherungsunternehmen und Reparaturdienstleister in der Verantwortung, die Eigentümer bei der Instandsetzung zu unterstützen. Eine Voraussetzung zur Kostenminimierung ist dabei eine auf die lokalen Gegebenheiten zugeschnittene Trocknungsstrategie, die sowohl die örtlichen klimatischen Bedingungen als auch die verwendeten Baumaterialien einbezieht.

Der Beitrag stellt eine Methode zur Bewertung von Trocknungsmaßnahmen hochwassergeschädigter Gebäude aus Ziegelmauerwerk vor. Die Verwendung von Simulationsrechnungen zur Vorhersage des Erfolges verschiedener Trocknungsverfahren wird anhand von unterschiedlichen historischen Mauerwerksarten gezeigt. Es lassen sich Aussagen über die Feuchteabgabe nach innen, über Anzahl und Dauer des Einsatzes von Luftentfeuchtungsgeräten, über den Verlauf der Trocknung, Gesamtdauer und Kosten der Maßnahmen treffen. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lichttechnisches und energetisches Verhalten von Fassaden moderner Verwaltungsbauten – Teil 2: Energetisches Verhalten
Authors: de Boer Jan
Published: April 2006

Im Teil 1 dieses Beitrages wurde auf die Auswirkung unterschiedlicher fassadentechnischer Lösungen auf die Raumbeleuchtungsverhältnisse und den Kunstlichteinsatz mittels einer Variation signifikanter Raum‐, Umgebungs‐ und Klimaparameter für eine Auswahl von zehn Fassadensystemen eingegangen. Im Teil 2 der Darstellung wird das energetische Zusammenspiel zwischen den von der Fassadenausführung abhängigen internen Wärmegewinnen für Beleuchtung und den solaren Wärmeeinträgen untersucht. Die Zusammenhänge werden anhand von vier als repräsentativ betrachteten Systemen dargestellt. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ThermoShield – ein Beitrag zur Wärmedämmung?
Authors: Fouad Nabil A. , Dorow Catrin , Richter Torsten
Published: April 2006

Seit einiger Zeit sind so genannte Thermobeschichtungen auf dem Markt, bei denen beworben wird, daß sie den Heizenergiebedarf bei Gebäuden erheblich reduzieren. Dabei handelt es sich um Fassadenfarben, z. B. das Produkt “ThermoShield”, denen mikroskopisch kleine, silanisierte, keramische Hohlkügelchen (Ceramic Bubbles) zugesetzt sind. In den Produktunterlagen zur genannten Beschichtung wird angegeben, daß die Energieeinsparungen bzw. die an einigen Stellen auch als Heizkostenersparnis bezeichneten Vorteile bis zu 30% betragen und herstellerseitig den verschiedenen Wirkanteilen von “ThermoShield” zugeschrieben werden können. Zur Überprüfung der vielversprechenden Produkteigenschaften wurden die thermischen Eigenschaften von Probekörpern, die mit “ThermoShield – Exterieur” beschichtet worden sind, im Rahmen einer an der Universität Hannover angefertigten Arbeit untersucht. Die Auswertung der Meßergebnisse zeigte, daß die mit “ThermoShield” beschichteten Probenkörper nicht die Eigenschaften aufwiesen, die bei einer wärmedämmenden Wirkung der Beschichtung zu erwarten wären. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Neue Erkenntnisse zur Wärmebrückenproblematik Sockelanschluß‐Schiene aus Aluminium
Authors: Lude Gerhard
Published: April 2006

Die bauübliche Konstruktion eines Sockelanschlusses bei Wärmedämmverbundsystemen mit Aluminiumschiene stellt eine gravierende Wärmebrücke dar. Die Auswirkungen auf den Wärmeschutz kleiner Gebäude sind erheblich. Sockelanschlüsse mit Aluminiumschiene sind nicht konform mit DIN 4108 Beiblatt 2. Daher muß nach Energieneinsparverordnung ein Wärmebrückenzuschlag von ΔU = 0,1 W/(m2K) auf die thermische Hülle berücksichtigt oder ein genauer Nachweis geführt werden. Bauphysikalisch stellt die Aluminiumschiene unter erhöhten Anforderungen ein vermeidbares Risiko der Tauwasser‐ und Schimmelbildung dar. Wärmbrückenfreie Lösungen sind industriell verfügbar. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of endothelialized tube in collagen gel as starting point for self‐developing capillary‐like network to construct three‐dimensional organs in vitro
Authors: Takei Takayuki , Sakai Shinji , Ono Tsutomu , Ijima Hiroyuki , Kawakami Koei
Published: April 2006

A possible strategy for creating three‐dimensional (3D) tissue‐engineered organs in vitro with similar volumes to the primary organs is to develop a capillary network throughout the constructs to provide sufficient oxygenation and nutrition to the cells composing them. Here, we propose a novel approach for the creation of a capillary‐like network in vitro, based on the spontaneous tube‐forming activity of vascular endothelial cells (ECs) in collagen gel. We fabricated a linear tube of 500 µm in diameter, the inner surface of which was filled with bovine carotid artery vascular endothelial cells (BECs), in type I collagen gel as a starting point for the formation of a capillary‐like network. The BECs exposed to a medium containing vascular endothelial growth factor (VEGF) migrated into the ambient gel around the tube. After 2 weeks of VEGF exposure, the distance of the migration into the ambient gel in the radial direction of the tube reached approximately 800 µm. Cross‐sections of capillary‐like structures composed of the migrating BECs, with a lumen‐like interior space, were observed in slices of the gel around the tube stained with hematoxylin–eosin (H&E). These results demonstrate that this approach using a pre‐established tube, which is composed of ECs, as a starting point for a self‐developing capillary‐like network is potentially useful for constructing 3D organs in vitro. © 2006 Wiley Periodicals, Inc.
Population dynamics and in situ kinetics of nitrifying bacteria in autotrophic nitrifying biofilms as determined by real‐time quantitative PCR
Authors: Kindaichi Tomonori , Kawano Yoshiko , Ito Tsukasa , Satoh Hisashi , Okabe Satoshi
Published: April 2006

Population dynamics of ammonia‐oxidizing bacteria (AOB) and uncultured Nitrospira‐like nitrite‐oxidizing bacteria (NOB) dominated in autotrophic nitrifying biofilms were determined by using real‐time quantitative polymerase chain reaction (RTQ‐PCR) and fluorescence in situ hybridization (FISH). Although two quantitative techniques gave the comparable results, the RTQ‐PCR assay was easier and faster than the FISH technique for quantification of both nitrifying bacteria in dense microcolony‐forming nitrifying biofilms. Using this RTQ‐PCR assay, we could successfully determine the maximum specific growth rate (µ = 0.021/h) of uncultured Nitrospira‐like NOB in the suspended enrichment culture. The population dynamics of nitrifying bacteria in the biofilm revealed that once they formed the biofilm, the both nitrifying bacteria grew slower than in planktonic cultures. We also calculated the spatial distributions of average specific growth rates of both nitrifying bacteria in the biofilm based on the concentration profiles of NH, NO, and O2, which were determined by microelectrodes, and the double‐Monod model. This simple model estimation could explain the stratified spatial distribution of AOB and Nitrospira‐like NOB in the biofilm. The combination of culture‐independent molecular techniques and microelectrode measurements is a very powerful approach to analyze the in situ kinetics and ecophysiology of nitrifying bacteria including uncultured Nitrospira‐like NOB in complex biofilm communities. © 2006 Wiley Periodicals, Inc.
Effect of the plant peptide regulator, phytosulfokine‐α, on the growth and Taxol production from Taxus sp. suspension cultures
Authors: Kim Beum Jun , Gibson Donna M. , Shuler Michael L.
Published: April 2006

Phytosulfokine‐α (PSK‐α) is a small plant peptide (5 amino acids) that displays characteristics typically associated with animal peptide hormones. PSK‐α was originally isolated based on its mitogenic activity with plant cultures; it has been reported to increase production of tropane alkaloids from Atropa belladonna, although its general influence on secondary metabolite production is unknown. The studies reported in this article were initiated to evaluate the effects of PSK‐α supplementation on production of Taxol™ (paclitaxel) from plant cell cultures of Taxus sp. particularly when methyl jasmonate (MeJA) is added as an elicitor of secondary metabolism. The response to PSK‐α supplementation was cell line dependent. Taxus cuspidata P93AF showed no statistically significant response to PSK‐α supplementation while Taxus canadensis C93AD and T. cuspidata PO93X displayed a concentration‐dependent response (up to 100 nM PSK‐α added in first 24 h of culture) with a decrease in initial growth rate, an increase in cell density (dry weight/fresh weight), and increased Taxol production. More remarkably with T. canadensis (C93AD), a very strong synergistic response of PSK‐α (100 nM) and methyl jasmonate (MeJA, 100 µM) elicitation was observed, resulting in Taxol level of 35.3 ± 2.1 mg/L or 1.83 ± 0.02 mg Taxol/g dry cell weight achieved at day 21, a level of approximately 10‐fold higher than for either treatment by itself. Although the level of Taxol production achieved is not remarkable, this synergistic treatment was able to partially revive taxane production in cultures that have lost productivity due to extended time (over 10 years) in continuous subculture. © 2006 Wiley Periodicals, Inc.
Analysis of cell growth and diffusion in a scaffold for cartilage tissue engineering
Authors: Chung C.A. , Yang C.W. , Chen C.W.
Published: April 2006

Developments in tissue engineering over the past decade have offered promising future for the repair and reconstruction of damaged tissues. To regenerate three dimensional and weight‐bearing implants, advances in biomaterials and manufacturing technologies prompted cell cultivations with natural or artificial scaffolds, in which cells are allowed to proliferate, migrate, and differentiate in vitro. In this article, we develop a mathematical model for cell growth in a porous scaffold. By treating the cell‐scaffold construct as a porous medium, a continuum model is set up based on basic principles of mass conservation. In addition to cell growth kinetics, we incorporate cell diffusion in the model to describe the effects of cell random walks. Computational results are compared to experimental data found in the literature. With this model, we are able to investigate cell motility, heterogeneous cell distributions, and non‐uniform seeding for tissue engineering applications. Results show that random walks tend to enhance uniform cell spreads in space, which in turn increases the probabilities for cells to acquire nutrients; therefore random walks are likely to be a positive contribution to the overall cell growth on scaffolds. © 2006 Wiley Periodicals, Inc.
Expression of viral capsid protein antigen against Epstein‐Barr virus in plastids of Nicotiana tabacum cv. SR1
Authors: Lee Maggie Y.T. , Zhou Yuanxiang , Lung Raymond W.M. , Chye Mee‐Len , Yip Wing‐Kin , Zee Sze‐Yong , Lam Eric
Published: April 2006

Epstein‐Barr virus (EBV) infects nearly 90% of adults worldwide and is the pathogenic source of a broad spectrum of malignancies originating from lymphoid and epithelial cells. Currently, no vaccine has been developed to immunologically inactivate this virus. In infected patients, anti‐EBV viral capsid antigen (VCA) immunoglobins represent some of the useful diagnostic markers for carcinoma development. To demonstrate that the EBV VCA antigen can be produced in plants, the plastid genome of tobacco (Nicotiana tabacum cv. SR1) was transformed with a VCA‐expressing cassette. The EBV VCA mRNA was actively transcribed in the transplastomic plants and antigen production was detected. This study indicates that plastid transformation could be a promising strategy in EBV VCA antigen production. © 2006 Wiley Periodicals, Inc.
pKa Switching Induced by the Change in the π‐Conjugated System Based on Photochromism
Authors: Odo Yuka , Matsuda Kenji , Irie Masahiro
Published: April 2006

Two diarylethene derivatives 1 a and 2 a containing a 2,5‐diaryl‐3‐thienyl group have been designed and synthesized. The pKa values of these compounds change upon photoirradiation. They have a phenol group as a proton source and a pyridinium group as an acceptor unit at each end of the π‐conjugated chain. The cyclization/cycloreversion reactions can be used to control the length of the π‐conjugated chain between the proton source and the acceptor. The change in the π‐conjugated chain length caused the pKa‐switching.
Microwave‐Assisted Suzuki Coupling Reactions with an Encapsulated Palladium Catalyst for Batch and Continuous‐Flow Transformations
Authors: Baxendale Ian R. , Griffiths‐Jones Charlotte M. , Ley Steven V. , Tranmer Geoffrey K.
Published: April 2006

This article describes the design, optimisation and development of a Suzuki cross‐coupling protocol mediated by an efficient palladium‐encapsulated catalyst (Pd EnCatTM) under microwave irradiation. The methodology has been used in both batch mode for classical library preparation and in continuous‐flow applications furnishing multigram quantities of material. Described is a method that uses direct focused microwave heating whilst applying an external cooling source. This enables a lower than normal bulk temperature to be maintained throughout the reaction period leading to significant improvements in the overall yield and purity of the reaction products. Additional aspects of this novel heating protocol are discussed in relation to the prolonged lifetime and enhanced reactivity of the immobilised catalyst system.
Bicyclic glutamic acid derivatives
Authors: Meyer Udo , Bisel Philippe , Weckert Edgar , Frahm August Wilhelm
Published: April 2006

For the second‐generation asymmetric synthesis of the trans‐tris(homoglutamic) acids via Strecker reaction of chiral ketimines, the cyanide addition as the key stereodifferentiating step produces mixtures of diastereomeric α‐amino nitrile esters the composition of which is independent of the reaction temperature and the type of the solvent, respectively. The subsequent hydrolysis is exclusively achieved with concentrated H2SO4 yielding diastereomeric mixtures of three secondary α‐amino α‐carbamoyl‐γ‐esters and two diastereomeric cis‐fused angular α‐carbamoyl γ‐lactams as bicyclic glutamic acid derivatives, gained from in situ stereomer differentiating cyclisation of the secondary cis‐α‐amino α‐carbamoyl‐γ‐esters. Separation was achieved by CC. The pure secondary trans‐α‐amino α‐carbamoyl‐γ‐esters cyclise on heating and treatment with concentrated H2SO4, respectively, to diastereomeric cis‐fused angular secondary α‐amino imides. Their hydrogenolysis led to the enantiomeric cis‐fused angular primary α‐amino imides. The configuration of all compounds was completely established by NMR methods, CD‐spectra, and by X‐ray analyses of the (αR,1R,5R)‐1‐carbamoyl‐2‐(1‐phenylethyl)‐2‐azabicyclo[3.3.0]octan‐3‐one and of the trans‐αS,1S,2R‐2‐ethoxycarbonylmethyl‐1‐(1‐phenylethylamino)cyclopentanecarboxamide. Chirality, 2006. © 2006 Wiley‐Liss, Inc.
“Jäder nor einen wönzigen Schlock”. Angewandte Biokatalyse
Authors: Roth Klaus
Published: April 2006

In den Vierziger Jahren des letzten Jahrhunderts entwickelte der bedeutende Chemiedidaktiker K.W. Crey für die Oberstufe eine Lehreinheit “Alkoholische Gärung”. Erst durch die im Stadtarchiv Goslar jüngst entdeckten Originalmanuskripte ist es möglich, dieses chemiedidaktische Meisterwerk kritisch zu würdigen. Der Aufbau der Lehreinheit wird dargestellt und seine aus heutiger Sicht fachlichen Mängel identifiziert. Dennoch erfüllt der Aufbau der Lehreinheit und das dahinter steckende didaktische Grundkonzept alle an den modernen Chemieunterricht gestellten Bedingung, insbesondere des Alltagsbezugs. Der Höhepunkt der Unterrichtseinheit, ein gemeinsames Schüler‐Lehrer‐Experiment, dürfte auch heute noch ein Höhepunkt im Chemieunterricht sein.
Strategien gegen Kälte
Authors: Hille‐Rehfeld Annette
Published: April 2006

Wechselwarme Tiere, deren Körpertemperatur sich der Umgebung angleicht, aber auch Pflanzen, müssen sich vor Frostschäden schützen. Bilden sich Eiskristalle im Organismus, so wird den Körperflüssigkeiten Wasser entzogen. Infolgedessen schrumpfen zelluläre Strukturen oder werden sogar zerstört.
RNA katalysiert Aldol‐Reaktion
Authors: Feil Sylvia
Published: April 2006

Für die Evolution einer hypothetischen RNA‐Welt dienen im Labor in vitro‐Versuche als Modell. Man geht davon aus, dass beim Entstehen der ersten Biomoleküle noch keine enzymatischen Proteine existierten. Vermutet wird, dass stattdessen RNA‐Moleküle die Aufgaben übernommen haben, die in der modernen Welt des Lebens von Protein‐Enzymen wahrgenommen werden.
Des Gold‐Katalysators glänzende Zukunft
Authors: Jaenicke Lothar
Published: April 2006

Sauerstoff‐funktionelle Erdöl‐bürtige Aliphate und Cycloaliphate wie Epoxide, Alkohole, Aldehyde, Ketone, Säuren sind Ausgangsmaterialien für “Plaste und Elaste”, Lacke und Detergentien, Kosmetika und Emulgatoren. Sie werden heutzutage mehrstufig und sehr wenige “grün” aus den Kohlenwasserstoffen hergestellt, entweder verhältnismäßig billig aber unverantwortlich umweltschädlich durch Chlorierung oder energieverschwendend, dadurch teuer, durch Peroxidierung. Im ersten Fall fallen nicht nur große Mengen Chlorid‐Abfall an, sondern auch toxische chlorierte Nebenprodukte; im anderen Nebenprodukte, für die es (noch?) keinen Markt gibt.
Metallfreie Katalyse
Authors: Feil Sylvia
Published: April 2006

Die Idee, organische Moleküle als Katalysatoren zu verwenden, wurde schon zu Beginn des letzten Jahrhunderts entwickelt. Aber erst in den letzten Jahren konnte gezeigt werden, dass dieses Prinzip vergleichbar effizient ist wie die herkömmliche Metallkatalyse.
Enzyme Isoselective Inhibitors: A Tool for Binding‐Trend Analysis
Authors: Ozeri Rachel , Khazanov Netaly , Perlman Nurit , Shokhen Michael , Albeck Amnon
Published: April 2006

A transition‐state analogue inhibitor that covalently reversibly binds to an enzyme formally consists of two parts: the chemical site, CS and the recognition site, RS. We have experimentally and theoretically demonstrated that the trend of binding affinity in a series of isoselective inhibitors (with identical RS and different CS fragments) depends mainly on their CS fragments. Isoselective inhibitors have the same affinity trend toward different enzymes of the same family with a common catalytic mechanism. Thus, very good correlation between experimentally determined and theoretically calculated Ki values was demonstrated. A practical outcome is the application of the described method as a tool for an expert analysis in virtual screening of inhibitor libraries and in the design of new enzyme inhibitors.
Anthropometry and the risk of epithelial ovarian cancer
Authors: Greer Julia B. , Modugno Francesmary , Ness Roberta B. , Allen Glenn O.
Published: April 2006

BACKGROUND

The association between anthropometric factors and ovarian cancer risk was investigated using data from 762 cases and 1348 controls participating in a population‐based case‐control study in the Delaware Valley from 1994–1998. Because factors such as oral contraceptive (OC), hormone therapy (HT), and parity may affect weight and hormone levels, the associations were examined in women with and without these characteristics.

METHODS

Unconditional logistic regression was used to calculate odds ratios and 95% confidence intervals while controlling for age, race, parity, family history of ovarian cancer, tubal ligation, and OC use.

RESULTS

Compared with controls, cases were taller and heavier in recent years and at age 18. Results did not differ by OC or HT use. However, anthropometric associations differed significantly based on parity, as increasing anthropometric measures were associated with increased ovarian cancer risk among nulliparous women only. Adjusted OR for recent body mass index (BMI) quartile 4 compared with quartile 1 for nulliparous women was 2.53 (95% confidence interval [CI]: 1.39, 4.61) compared with 0.96 (95% CI: 0.70, 1.31) for parous women. Additionally, adult weight gain was significant only for nulliparous women. Adjusted OR for weight change (recent to age 18) quartile 4 compared with quartile 1 for nulliparous women was 3.73 (95% CI: 1.88, 7.42) versus 1.09 (95% CI: 0.78, 1.51) for parous women.

CONCLUSIONS

BMI and weight in women's adult lifetime may be positively associated with ovarian cancer risk. Observations were most apparent for nulliparous women, possibly reflecting an interaction between local inflammation caused by incessant ovulation and increased estrogen exposure on ovarian epithelium. Cancer 2006. © 2006 American Cancer Society.
Impact of estrogen receptor expression and other clinicopathologic features on tamoxifen use in ductal carcinoma in situ
Authors: Hird R. Barry , Chang Alfred , Cimmino Vincent , Diehl Kathleen , Sabel Michael , Kleer Celina , Helvie Mark , Schott Anne , Young Jennifer , Hayes Daniel , Newman Lisa
Published: April 2006

BACKGROUND

Recent data have demonstrated that benefit from adjuvant tamoxifen therapy for patients with ductal carcinoma in situ (DCIS) is limited to estrogen receptor (ER)‐positive lesions. The objective of the current study was to correlate clinicopathologic features of DCIS with ER expression and the impact of this information on tamoxifen counseling.

METHODS

Women with DCIS who were treated from 2001 to 2004 were evaluated. Routine ER staining was initiated in January 2003.

RESULTS

Ninety‐four women (mean age, 57.6 years) were analyzed. The mean DCIS size was 0.98 cm. ER‐staining was performed in 55 lesions, and 76% were ER‐positive. All Grade 1 and 2 DCIS lesions were ER‐positive, compared with 54% of high‐grade lesions (P<.001); no other clinicopathologic feature significantly predicted ER status. Overall, 58 patients (62%) were offered tamoxifen, and the rates were similar for the pre‐ER and post‐ER staining periods. In the pre‐ER staining period, surgical treatment and grade were associated with offering tamoxifen (75% of patients who underwent breast conservation vs. 40% of patients who underwent mastectomy; P = .03; 78% of patients with Grade 1 or 2 lesions vs. 45% of patients with Grade 3 lesions; P = .04). In the post‐ER staining period, however, only ER status was correlated significantly with offering tamoxifen (71% of patients with ER‐positive lesions vs. 31% of patients with ER‐negative lesions; P = .01). Approximately 66% of patients who were offered tamoxifen agreed to treatment (approximately 33% of the total DCIS study sample). No clinicopathologic features predicted for tamoxifen acceptance by patients in either the pre‐ER or post‐ER staining periods.

CONCLUSIONS

Seventy‐five percent of DCIS lesions were ER‐positive. ER staining significantly influenced the likelihood that clinicians would offer tamoxifen to patients with DCIS, but it had no impact on whether patients accepted treatment. Cancer 2006. © 2006 American Cancer Society.
Particle embolization of recurrent hepatocellular carcinoma after hepatectomy
Authors: Covey Anne M. , Maluccio Mary A. , Schubert Johanna , BenPorat Leah , Brody Lynn A. , Sofocleous Constantinos T. , Getrajdman George I. , Fong Yuman , Brown Karen T.
Published: April 2006

BACKGROUND

Complete surgical resection is the mainstay of treatment for patients with hepatocellular carcinoma (HCC). Unfortunately, most patients ultimately develop disease recurrence and the median survival from the time of recurrence is <1 year. The purpose of the current study was to review the authors' experience using bland hepatic arterial embolization to treat recurrent HCC after definitive surgical resection.

METHODS

The authors reviewed their single‐center hepatic embolization database from 1995 through 2004 to identify patients who underwent bland hepatic arterial embolization for disease recurrence. Data analyzed included patient demographics, Okuda stage and Child score, imaging findings, and embolization variables. Recurrence‐free survival (from surgery to disease recurrence) and survival time (from recurrence to last follow‐up) were calculated using the Kaplan‐Meier method.

RESULTS

The authors identified 45 patients treated with bland embolization for recurrent HCC after resection. Six patients also underwent ablative therapy after embolization. Of the 45 patients, 42 (93.3%) patients had Okuda Stage 1 disease. The median time to recurrence was 13 months. The median survival after embolization was 46 months, and actuarial survival rates at 1 year, 2 years, and 5 years after recurrence were 86%, 74%, and 47%, respectively, with a median follow‐up of 31 months. Patients who developed disease recurrence with a solitary lesion had a significantly improved survival (P = .03) At the time of last follow‐up, 3 patients (6.6%) were alive with no evidence of viable disease.

CONCLUSIONS

Bland arterial embolization was found to be an effective method of salvage therapy for patients with good liver function with recurrent HCC after prior surgical resection. Patients whose disease recurred with a solitary lesion appear to have a significantly increased survival compared with patients who develop disease recurrence with multiple tumors. A small proportion of patients can be rendered without evidence of viable disease. Cancer 2006. © 2006 American Cancer Society.
The “y” symbol: An important classification tool for neoadjuvant cancer treatment
Authors: Brierley James D. , Greene Frederick L. , Sobin Leslie H. , Wittekind Christian
Published: April 2006

The use of preoperative adjuvant therapy is becoming increasingly frequent for a number of tumors. Therefore, the pathologic classification after preoperative therapy may not reflect the true anatomic extent of disease before treatment. To indicate that the clinical or pathologic classification has been determined after preoperative therapy, the TNM classification of the International Union Against Cancer and American Joint Committee on Cancer includes a prefix “y,” with yc used for clinical and yp for pathologic classifications.
The “Non‐Reaction” of Ground‐State Triplet Carbon Atoms with Water Revisited
Authors: Schreiner Peter R. , Reisenauer H. Peter
Published: April 2006

We introduce a novel experimental setup for the generation of carbon atoms by means of pulsed laser ablation with a pulse rate optimized to avoid warming of the matrix. The combination of this technique with annealing of the matrix, recooling, and spectral recording (e.g. IR) allowed us to differentiate between the reactivity of triplet and singlet carbon atoms towards water under matrix‐isolation conditions. Our experimental procedure assures the relaxation of all unreacted carbon atoms to their triplet ground state in the 10 K matrix before spectral recording. In agreement with CCSD(T)/cc‐pVTZ+ZPVE computational data and earlier lower level results, we find that triplet carbon atoms indeed do not react with water, despite their high initial energy. Intersystem crossing of the triplet to singlet states of hydroxy carbene are less important, as the barriers for rearrangement of the initial complex of triplet carbon atoms and water to covalently bound species are too high, and dissociation is more likely. We found no evidence for a direct OH bond‐insertion path for triplet carbon atoms. Self‐condensation reactions of triplet carbon atoms are clearly favored and yield carbon clusters that show reactivity of their own. The proposed formation of aldoses in extraterrestrial environments can therefore only derive from “hot” carbon atoms or through photoreactions.
Fingerprints of Damped Quantum Rotation Observed in Solid‐State Proton NMR Spectra
Authors: Gutsche Peter , Schmitt Heike , Haeberlen Ulrich , Ratajczyk Tomasz , Szymanski Slawomir
Published: April 2006

1H NMR spectra of the methyl group in an oriented crystal sample of methylmalonic acid with all three non‐methyl protons replaced by deuterons are interpreted in terms of the damped quantum rotation (DQR) theory of NMR line shapes. The DQR approach offers a perfect theoretical reproduction of the observed spectra while the conventional Alexander‐Binsch line‐shape model shows evident defects in the present case. The temperature trends of the quantities characterizing the coherent and incoherent dynamics of the methyl group in the DQR approach (the effective tunnelling frequency and two coherence‐damping rates) derived from the spectra are fairly reproduced using a model reported previously. The present findings provide further evidence of limitations to the validity of the common belief that molecular rate processes in condensed phases are necessarily classical.
Alternative Low‐Energy Mechanisms for Isotopic Exchange in Gas‐Phase D2O–H+(H2O)n Reactions
Authors: Mella Massimo , Ponti Alessandro
Published: April 2006

Molecular‐dynamics (MD) trajectories and high‐level ab initio methods have been used to study the low‐energy mechanism for D2O–H+(H2O)n reactions. At low collisional energies, MD simulations show that the collisional complexes are long‐lived and undergo fast monomolecular isomerization, converting between different isomers within 50–500 ps. Such processes, primarily involving water‐molecule shifts along a water chain, require the surmounting of very‐low‐energy barriers and present sizable non‐ Rice–Ramsperger–Kassel–Marcus (RRKM) effects, which are interpreted as a lack of randomization of the internal kinetic energy. Interestingly, the rate of water shifts was found to increase upon increasing the size of the cluster. Based on these findings, we propose to incorporate the following steps into the mechanism for low‐energy isotopic scrambling these D2O–H+(H2O)n reactions: a) formation of the collisional complex [H+(H2O)nD2O]* in a vibro‐rotational excited state; b) incorporation of the heavy‐water molecule in the cluster core as HD2O+ by means of isomerization involving molecular shifts; c) displacement of solvation molecules from the first shell of HD2O+ inducing de‐deuteration (shift of a D+ to a neighbor water molecule); d) reorganization of the clusters and/or expulsion of one of the isotopic variants of water (H2O, HDO or D2O) from the periphery of the complex.
Recent Progress in Ultrafast X‐ray Diffraction
Authors: Bargheer M. , Zhavoronkov N. , Woerner M. , Elsaesser T.
Published: April 2006

X‐ray diffraction with femtosecond time‐resolution represents a direct probe of ultrafast structural changes in condensed matter. The generation of ultrashort X‐ray pulses in laser‐driven plasma and/or accelerator‐based sources has made substantial progress, and has allowed for studies of transient structures with an unprecedented accuracy. Herein, recent work on transient crystalline structures is reviewed, with the focus on laser‐based experiments.
Linked Crystallites in the Conducting Topmost Layer of Polymer Bilayer Films Controlled by Temperature: From Micro‐ to Nanocrystallites
Authors: Laukhina Elena , Tkacheva Vladislava , Khasanov Salavat , Zorina Leokadia , Gómez‐Segura Jordi , Pérez del Pino Angel , Veciana Jaume , Laukhin Vladimir , Rovira Concepció
Published: April 2006

Temperature has great impact on the structure and size of the linked crystallites of the conducting topmost layer formed at the surface of a polycarbonate film via the reaction BEDT‐TTF+IBr [BEDT‐TTF=bis(ethylenedithio)tetrathiafulvalene]. We show that fine temperature control permits formation of a semiconducting topmost layer of α′‐(BEDT‐TTF)2(IxBr1−x)3 crystallites with either micro‐ or nanometre size, a result that opens a route to miniaturized conducting plastic materials.
Managing conflict during an organizational acquisition
Authors: Cohen Cynthia F. , Birkin Stanley J. , Cohen Murray E. , Garfield Monica J. , Webb Harold W.
Published: April 2006

Conflict frequently arises during an organizational acquisition, and how a company manages that conflict has an impact on the success of the acquisition. Software developers, testers, and managers of a recently acquired organization reported profound changes in organizational culture and numerous potential sources of conflict. Conflict was generally well managed by effectively handling economic rewards, the balancing of power, cultural changes, and emotional reactions to the acquisition.
A Systematic Exploration of Nickel(II)/Acetate/Di‐2‐pyridyl Ketone Chemistry: Neutral and Cationic Tetranuclear Clusters, and a Novel Mononuclear Complex
Authors: Efthymiou Constantinos G. , Raptopoulou Catherine P. , Terzis Aris , Boča Roman , Korabic Maria , Mrozinski Jerzy , Perlepes Spyros P. , Bakalbassis Evangelos G.
Published: April 2006

The further use of di‐2‐pyridyl ketone [(2‐py)2CO] innickel(II) acetate chemistry has been investigated. Various synthetic procedures have led to the synthesis ofcomplexes [Ni4(O2CMe)2{(2‐py)2C(OH)O}4(H2O)2](ClO4)2 (1), [Ni(O2CMe){(2‐py)2C(OH)2}{(2‐py)2CO}](ClO4)·H2O (2·H2O), [Ni4(O2CMe)3{(2‐py)2C(OH)O}4](ClO4)·2H2O·2EtOH (3·2H2O·2EtOH), [Ni4(O2CMe)4{(2‐py)2C(OH)O}4]·2MeCN (4·2MeCN), and [Ni4(O2CMe)3{(2‐py)2C(OH)O}4](O2CMe)·6H2O·MeCN (5·6H2O·MeCN). The NiII‐mediated hydrolysis of (2‐py)2CO to give the coordinated molecule (2‐py)2C(OH)2 or the monoanion (2‐py)2C(OH)O– involves nucleophilic attack by H2O on the carbonyl group. The NiII ion in 2·H2O is coordinated by one monodentate acetate, one N,N′,O‐tridentate chelating (2‐py)2C(OH)2 molecule, and one N,N′‐bidentate chelating (2‐py)2CO ligand. The tetranuclear cluster cation of 1 has a cubane {Ni4(μ3‐OR)4}4+ core with NiII ions and deprotonated oxygen atoms occupying alternate vertices. The [Ni4(O2CMe)3{(2‐py)2C(OH)O}4]+ cations present in the complexes 3·2H2O·2EtOH and 5·6H2O·MeCN have almost identical cubane structures that are different from the structure of the cation of 1. The four metal ions in the centrosymmetric molecules of 4·2MeCN are located at four vertices of a defect dicubane (with two missing vertices) and are bridged by six oxygen atoms. Characteristic IR bands are discussed in terms of the known structures of 1–5. The magnetic data for the NiII cubane 1 has been modeled with two Jvalues, and shows that the coupling consists of two ferromagnetically coupled pairs that are antiferromagnetically coupled to give a diamagnetic ground state. The magneticproperties of 4 have been modeled with three J values, andreveal competing antiferromagnetic and ferromagneticcoupling between the four NiII ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
(Diphosphane monosulfide)platinum(II) Complexes for Hydroformylation Reactions: Their Catalytic Activity and a High‐Pressure NMR Mechanistic Study
Authors: Lofù Antonio , Mastrorilli Piero , Nobile Cosimo F. , Suranna Gian P. , Frediani Piero , Iggo Jonathan
Published: April 2006

The neutral complexes of formula [κ2P,S‐(dppmS)Pt(CH3)(Cl)] (1), [κ2P,S‐(dppeS)Pt(CH3)(Cl)] (2) and [κ2P,S‐(dpppS)Pt(CH3)(Cl)] (3) [dppmS = Ph2PCH2P(S)Ph2; dppeS = Ph2P(CH2)2P(S)Ph2; dpppS = Ph2P(CH2)3P(S)Ph2] are active catalyst precursors for the hydroformylation of 1‐octene in methyl isobutyl ketone. The order of reactivity found is3 > 2 > 1. Surprisingly, the cationic complexes [κ2P,S‐(dppeS)Pt(CH3)(CH3CN)]BF4 (4a) and [{κP,μ‐κS‐(dppeS)Pt(CH3)}2][BF4]2 (5) are less active than the analogous neutral complex 2. High‐pressure NMR studies revealed that, at 20 °C under 1 to 50 bar of syngas, and in the presence of SnCl2, both 2 and 4a react immediately to form the same acetyl complex (8). However, in the absence of SnCl2, the methyl carbonyl complex [κ2P,S‐(dppeS)Pt(CH3)(CO)]+ (9), which is formed from 4a and CO, does not undergo insertion to give the acetyl complex, even under 50 bar of syngas. Thus, the role of SnCl2 is not only to create a vacant site for CO coordination and to lower the energy barrier for the hydrogenolysis, but also to assist migration of the alkyl group in the CO insertion step. High‐pressure NMR studies of the working reaction solution, under steady‐state conditions, found no evidence for intermediates in which the phosphane sulfide group shows hemilabile behaviour during catalysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
The “Building‐Block” Assembly of a [Ni12Mn6] Aggregate
Authors: Wu Gang , Clérac Rodolphe , Wernsdorfer Wolfgang , Qiu Shilun , Anson Christopher E. , Hewitt Ian J. , Powell Annie K.
Published: April 2006

Reaction of MnII(bdoa)(H2O)3 with Ni(CH3COO)2·3H2O in methanol gives a heterometallic cluster, [Ni12Mn6(bdoa)6(O2CMe)12(μ3‐OMe)12(MeOH)12]·21MeOH, which was structurally characterised by single‐crystal X‐ray diffraction and possesses three self‐assembled tetranuclear nickel cubes connected by a MnII6(bdoa)6(CH3COO)3 subunit. The magnetic properties were studied in detail and indicate that the compound possesses a high density of spin states with small energy gaps between them. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Asymmetric Synthesis of Antithrombotic Agent M55529: The First Enantioselective Cyclic N,O‐Acetal Formation
Authors: Saitoh Fumihiko , Nishida Hidemitsu , Mukaihira Takafumi , Aikawa Kohsuke , Mikami Koichi
Published: April 2006

The first asymmetric synthesis of antithrombotic agent M55529 is reported, wherein the first enantioselective cyclic N,O‐acetal formation is clarified. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)