bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semicarbazide‐Functionalized Silicate Nanoparticles for Peptide Ligation
Authors: Doussineau Tristan , Durand Jean‐Olivier , El‐Mahdi Ouafâa , Maillet Céline , Melnyk Oleg , Olivier Christophe , Smaïhi Monique 
Published: May 2006

AbstractMonodisperse silicate nanoparticles have been used for the development of a site‐specific ligation method that enables the control of the biomolecule orientation at the solid–liquid interface. Two types of zeolite nanoparticles were studied: zeolite β, which possesses a Si/Al ratio of 25, and silicalite‐1, which is a fully silicic material. Zeolite‐type materials are microporous silicate with pores of a well‐defined size ranging from 2 to 20 Å. Semicarbazide‐functionalized silicate colloids have been prepared for the site‐specific ligation of COCHO‐modified polypeptides. The obtained colloidal suspensions have been characterized by complementary techniques providing information on the size distribution, morphology, and porosity of the particles and chemical nature of the grafting. The specificity of the particles’ surface for the semicarbazide group has been studied by fluorescence spectroscopy with two peptides labeled with rhodamine. A first peptide bares a COCHO functionality, which should bind covalently with the semicarbazide surface. The second peptide bares an amine end‐group, which should interact by nonspecific adsorption with the surface. The results demonstrated that the peptide/colloids’ reactivity is dramatically influenced by the chemical composition of the particles’ surface. Indeed, while zeolite β (aluminosilicate) particles react indifferently with the two peptides, silicalite particles (pure silicate) anchor exclusively the peptide bearing the COCHO functionality. This particular physisorption phenomenon of zeolite β is attributed to the aluminum atoms present at the particles’ surface, which have a specific affinity for peptides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Design of Cyano‐Bridged Coordination Polymers Based on Tetrahedral Rhenium Cluster Cyanide Complexes and 3d Transition Metals
Authors: Efremova Olga A. , Mironov Yuri V. , Fedorov Vladimir E. 
Published: May 2006

AbstractThis microreview surveys some novel possibilities in the design of coordination polymers using the tetrahedral rhenium cluster chalcocyanide complexes [Re4Q4(CN)12]4– (Q = S, Se, Te) and 3d transition metals. The large number of cyano groups in the cluster complexes [Re4Q4(CN)12]4–, their ambidentate character and their strong ability to form cyano‐bridged structures lead to the formation of a wide variety of coordination polymers with different architectures that depend on the reaction conditions. The diversity of the coordination environment of the transition metals has been used as one of the most important factors to control the dimensionality of the crystal structures of the target compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
First Example of Dendrons as Topological Amplifiers
Authors: Turrin Cédric‐Olivier , Maraval Alexandrine , Magro Germinal , Maraval Valérie , Caminade Anne‐Marie , Majoral Jean‐Pierre 
Published: May 2006

AbstractA phosphorus‐containing dendron was synthesized and grafted to a tetraphosphorus macrocycle. The presence of such bulky substituents allowed for the first time the amplification of topological differences in the macrocycle. These differences become detectable by 31P NMR spectroscopy, with the appearance of several signals for the phosphorus atoms included in the macrocycle. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Reactions of Aminobis(phenolate)‐Supported Dioxidotungsten(VI) and Dioxidomolybdenum(VI) Complexes
Authors: Lehtonen Ari , Sillanpää Reijo 
Published: May 2006

AbstractThe dioxidotungsten(VI) and ‐molybdenum(VI) complexes [WO2(O2NOMe)] (1), [MoO2(O2NOMe)] (2) and [{MoO2(O2NMe)}2] (3) [O2NOMe methoxyethylamino‐N,N‐bis(2‐methylene‐4,6‐dimethylphenolate) dianion, O2NMe = methylamino‐N,N‐bis(2‐methylene‐4,6‐dimethylphenolate) dianion] can react with chloride sources (Me3SiCl, SOCl2) to form resultant monooxido dichloro compounds [WOCl2(O2NOMe)] (4), [MoOCl2(O2NOMe)] (5) and [MoOCl2(O2NMe)] (6), respectively. The reaction of tungsten complex yields of the mixture of cis‐4 and trans‐4, which can be separated and characterized. The reactions of analogous molybdenum complexes with Me3SiCl yield trans isomers of 5 and 6 as individual products. Reaction of dioxidotungsten complex 1 with isopropyl isocyanate was found to produce a tungsten(VI) complex [W(O2NOMe)(N‐iPr)(L)] (7) (L = N,N′‐diisopropylureate) with a terminal imido group and a bidentate ureate ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Reactivity of β‐Bromo‐β‐Substituted Dehydroalanines
Authors: Ferreira Paula M. T. , Monteiro Luís S. 
Published: May 2006

AbstractThe methyl ester of N‐tert‐butoxycarbonyl‐(Z)‐β‐bromo‐β‐(1,2,4‐triazol‐1‐yl)dehydroalanine was prepared by treatment of the methyl ester of N‐tert‐butoxycarbonyl‐(E)‐β‐(1,2,4‐triazol‐1‐yl)dehydroalanine with N‐bromosuccinimide (NBS), followed by Et3N. The reactivities of this compound and of our previously synthesized methyl ester of N‐tert‐butoxycarbonyl‐β,β‐dibromodehydroalanine towards several nucleophiles were studied, and it was found that these compounds react with oxygen nucleophiles to give the corresponding α‐alkoxy‐β,β‐disubstituted alanines. Addition to the α‐carbon atom also occurred when the β,β‐dibromodehydroalanine derivative was treated with primary amines, giving α‐amino‐β,β‐dibromoalanines. Treatment of the β‐bromo‐β‐(1,2,4‐triazol‐1‐yl)dehydroalanine derivative with amines gave α‐(alkylamino)‐β‐(alkylimino)alanines in high yields. These iminoalanines afforded α‐aminoglycines when treated with silica in dichloromethane. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
An Efficient and Diastereoselective Intramolecular 1,3‐Dipolar Cycloaddition of Cyclic Azomethine Ylides and Nitrones
Authors: Pedrosa Rafael , Andrés Celia , Nieto Javier , Pérez‐Cuadrado Cristóbal , San Francisco Iván 
Published: May 2006

AbstractNitrones and azomethine ylides formed by condensation of chiral 2‐formyl‐perhydro benzoxazines and N‐substituted hydroxylamines or cyclic α‐amino acids cyclize intramolecularly yielding polycyclic isoxazolidine or pyrrolidine derivatives, respectively, with total diastereoselectivity. On the contrary, stabilized azomethine ylides derived from methyl prolinate undergo the cyclization products in very low yields.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis of N‐(3‐Phenylpropyl)‐Substituted Tricyclic ABE Ring Analogues of the Alkaloid Methyllycaconitine
Authors: Lehmann Anna , Brocke Constanze , Barker David , Brimble Margaret A. 
Published: May 2006

AbstractThe synthesis of several ABE tricyclic analogues 5, 31 and 32 of the alkaloid methyllycaconitine (1) is reported. The analogues contain two key pharmacophores: a tertiary N‐(3‐phenylpropyl) substituent attached to a 3‐azabicyclo[3.3.1]nonane ring system and a 2‐(3‐methyl‐2,5‐dioxopyrrolidin‐1‐yl)benzoate ester. Double Mannich reaction of the cyclic β‐keto esters 6 and 17 with the bis(aminol) ether 7 using methyltrichlorosilane as an activating agent provided an efficient method for the construction of the 3‐azabicyclo[3.3.1]nonanes 8 and 18. Ring‐closing metathesis of the derived dienes 11, 19, and 20 afforded the tricyclic ethers 12, 21, and 22, respectively, the C‐8 ester of which was reduced to a hydroxymethyl group to form the ABE tricyclic analogues 13, 23, and 24. Conversion of the alcohol 13 to the anthranilate ester 14 using N‐(trifluoroacetyl)anthranilic acid followed by fusion with methylsuccinic anhydride afforded the analogue 5 containing the key N‐(methylsuccinimido)anthranilate pharmacophore. In the case of the alcohols 23 and 24 the 2‐(3‐methyl‐2,5‐dioxopyrrolidin‐1‐yl)benzoate ester pharmacophore was appended by direct esterification with unsaturated acid 28 followed by hydrogenation to the ABE tricyclic compounds 33 and 34. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Pyriporphyrin – A Porphyrin Homologue Containing A Built‐in Pyridine Moiety
Authors: Myśliborski Radomir , Latos‐Grażyński Lechosław , Szterenberg Ludmiła 
Published: May 2006

AbstractPyriporphyrin 1 (6,11,16,21‐tetraaryl‐22‐aza‐m‐benziporphyrin), the simplest homologue of 5,10,15,20‐tetraarylporphyrin can be constructed by replacement of one of the pyrrole rings of 5,10,15,20‐tetraarylporphyrin with a pyridine moiety, linked to the macrocycle through α,α′‐carbon atoms. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Retracted:It's all in the timing: measuring emotional reactions to stereotype threat before and after taking a test
Authors: Marx David M. , Stapel Diederik A. 
Published: May 2006

AbstractStereotype threat is often described as resulting from increased anxiety over confirming a negative stereotype about one's group (Steele, 1997). However, variations in the type of emotional reactions targets experience as a function of stereotype threat has never been examined systematically before and after taking a test, thus it is unclear whether targets experience different emotions at different points in the testing session. The present study investigated this issue of emotional specificity. Results demonstrate that targets of a negative stereotype, but not non‐targets, experienced heightened anxiety prior to taking a test under stereotype threat conditions and heightened frustration once the test was concluded. No effects were found in the non‐stereotype threat conditions. These findings, therefore, highlight the specific affective states that targets and non‐targets experience in threat and non‐threat conditions, as well as how these affective states can be assessed using self‐report measures. Copyright © 2006 John Wiley & Sons, Ltd.
A comparison of SRTM and high‐resolution digital elevation models and their use in catchment geomorphology and hydrology: Australian examples
Authors: Hancock G. R. , Martinez C. , Evans K. G. , Moliere D. R. 
Published: May 2006

AbstractThe recently released Shuttle Radar Topography Mission (SRTM) 3‐arc second digital elevation data set provides a complete global coverage of the Earth's land surface. In this paper we examine the SRTM data for three catchments in Australia over a range of climates, geology and resultant geomorphology. To test this new data set the SRTM data are compared with high resolution digital elevation models. We use basic hydrological and geomorphological statistics and descriptors such as the area–slope relationship, cumulative area distribution and hypsometric curve, along with Strahler and networking statistics. The above measures describe the surface morphology of a catchment, therefore integrating catchment geology, climate and vegetation. The SRTM data were also assessed as input into the SIBERIA landscape evolution and soil erosion model as were runoff properties, using a wetness index. The results demonstrate that the 90 m SRTM data provide a poor catchment representation. Hillslopes appear as a linked set of facets and display little of the complex curvature that is observed in high resolution data. While catchment area–slope and area–elevation (hypsometry) properties are largely correct, catchment area, relief and shape (as measured by the width function) are poorly captured by the SRTM data. Catchment networking statistics are also variable. The large grid size of the SRTM data also results in incorrect drainage network patterns and different runoff properties. Consequently, care must be used for quantitative assessment of catchment hydrology and geomorphology, as in all cases SRTM‐derived catchment area is incorrect and smaller digital elevation grid sizes are required for accurate catchment‐wide assessment. While only a limited number of catchments have been examined, we believe our findings are applicable to other areas. © Crown Copyright 2006. Reproduced with the permission of the Controller of HMSO. Published by John Wiley & Sons, Ltd.
Flame‐retardant action of red phosphorus/magnesium oxide and red phosphorus/iron oxide compositions in recycled PET
Authors: Laoutid F. , Ferry L. , Lopez‐Cuesta J. M. , Crespy A. 
Published: May 2006

AbstractRed phosphorus was combined with metallic oxides Fe2O3 and MgO to improve the fire properties of recycled PET. Both Fe2O3 and MgO act as co‐synergist agents at a total loading of 5 wt%. The analysis by diffraction X of the char formed during combustion shows that transformation of Fe2O3 to Fe3O4 occurs. Fe2O3 favours the oxidation and improves the effectiveness of red phosphorus. It is suggested that MgO interacts with acidic end groups of PET and forms a thermal stable residue. The thermal decomposition of recycled PET containing red phosphorus combined with Fe and Mg oxides was studied by thermal analysis and leads to an increase in char formation. While the incorporation of Fe2O3 in this ternary blend maintains the mechanical properties of PET, the reactivity of MgO leads to a brittle material. The use of reinforcements (talc and glass fibres) to mechanically stabilize the char formed during combustion of ternary blend with Fe2O3 entails a further decrease in heat release rate, nevertheless impact resistance of the material decreases dramatically. Copyright © 2005 John Wiley & Sons, Ltd.
The identity of Paeonia corsica Sieber ex Tausch (Paeoniaceae), with special reference to its relationship with P. mascula (L.) Mill.
Authors: De‐Yuan Hong , Xiao‐Quan Wang 
Published: May 2006

AbstractThe taxonomy of the genus Paeonia in central Mediterranean islands has been controversial, with number of recognized taxa changing greatly from one species without infraspecific division to three species or five infraspecific taxa in one species, and with the number of synonyms as great as 30. In the present work, the taxonomic history is thoroughly reviewed and a taxonomic revision is made based on extensive field work, chromosome observation, population sampling, examination of a large amount of herbarium specimens, and subsequent statistic analysis. As a result of the studies P. corsica Sieber ex Tausch, an ignored specific name, is restored at specific rank, and the species is found distinct from all the three subspecies of P. mascula in this region in having mostly nine (vs ≥ 10) leaflets/segments, shorter hairs (1.5 mm vs 3 mm long) on carpels, rather densely holosericeous (vs glabrous or very sparsely hirsute) on the lower surface of leaves. It is a diploid, confined to Corsica France), Sardinia (Italy), Ionian Islands and Akarnania Province of Greece, whereas P. mascula is a tetraploid, widely distributed from Spain to Turkey and Iraq, but not in Corsica, Sardinia and W Greece. In addition, type specimens of four taxa are designated, and 29 botanic names are listed as synonyms of P. corsica in this paper. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Studien über oligozäne Populus ‐Arten aus der Weißelstersenke südlich von Leipzig, Sachsen (Deutschland)
Authors: Reuschel Ch. , Walther H. 
Published: May 2006

AbstractAus dem höheren Paläogen der Weißelstersenke (Weißelsterbecken) südlich von Leipzig (Sachsen, Deutschland) werden von mehreren Fundorten zwei fossile Populus ‐Arten [P. germanica (Menzel) Walther und P. zaddachii Heer] nach Merkmalskomplexen der Blattmorphologie und Epidermisstruktur an mehr als 500 Belegen aus paläogenen (Unteroligozän bis Oligo‐/Miozän) Sedimenten unterschiedlicher Fazies untersucht. Eingehende Vergleiche mit rezenten Populus ‐Arten der Sektionen Leucoides Spach, Leuce Duby und Tacamahaca Spach ergeben bestimmte Analogien zur fossilen Formart Populus zaddachii. Vor allem mit den heute in China (1300–3500 m Höhe) verbreiteten P. lasiocarpa Oliv. und P. wilsonii Schneider bestehen sowohl in der Blattmorphologie als auch in der Epidermisstruktur große Übereinstimmungen. Die in der Blattmorphologie äußerst variable Morphospezies Populus germanica ist eine sehr ursprüngliche Pappel‐Art, deren Blätter als archaisches Merkmal eine Subpeltation aufweisen können. Zu P. germanica konnte bisher keine analoge rezente Pappel‐Art gefunden werden.Populus germanica ist als dominantes Florenelement der azonalen Waldvegetationen (flussbegleitende Auenwälder) aus dem tiefen Unteroligozän, Oberoligozän und Oligo/Miozän von Mitteldeutschland bekannt.Populus zaddachii kommt im Oligozän Mitteleuropas (z. B. Sachsen) und im Umfeld von Kaliningrad (Russland) in den alttertiären „Baltischen Floren“ vor. In den meeresnahen Oligozän‐Floren (z. B. Florenkomplex Thierbach) kann diese Art prädominant gemeinsam mit P. germanica als Auenwaldelement auftreten. In den tief unteroligozänen vulkanischen Floren des Böhmischen Mittelgebirges (Tschechische Republik) und der Südlausitz (Deutschland) ist sie nur ein akzessorisches Element des Mixed Mesophytic Forest (Kundratice, Bechlejovice/Tschechische Republik; Seifhennersdorf, Südostoberlausitz /Deutschland). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bomarea edulis (Tussac) Herb. a nearly forgotten pre‐Columbian cultivated plant and its closest relatives (Alstroemeriaceae)
Authors: Hofreiter A. 
Published: May 2006

AbstractThe morphological variability, distribution, tuber anatomy, use and taxonomy of Bomarea edulis are discussed. Bomarea edulis is distributed from Mexico to Argentina. Its wide distribution may be caused by the fact that the root tubers have been used as food. A well developed plant can bear more than 20 root tubers with 5 cm in diameter. The tubers are named with a number of local names, best known as “white Jerusalem artichoke” or in German as “Bomarie”, respectively. Bomarea edulis is morphologically variable, this and the wide distribution have caused 23 synonyms, the very similar and also edible B. ovata has seven synonyms. Bomarea edulis is compared to its closest similar species and a key is given to determine them. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Species diversity and species composition of epiphytic bryophytes and lichens – a comparison of managed and unmanaged beech forests in NE Germany
Authors: Friedel A. , v.Oheimb G. , Dengler J. , Härdtle W. 
Published: May 2006

AbstractThe impact of forest management on the species diversity and species composition of epiphytic bryophytes and lichens in beech forests (Fagus sylvatica) of NE Germany was analysed. The investigations were carried out in one unmanaged and in one managed forest, with 45 sample plots of 400 m2each. In the sample plots, the presence of the epiphytes on 2–4 randomly chosen trees (100 trees per forest) and seven environmental variables were recorded. The total number of species and the mean lichen density per mantle area was higher in the unmanaged forest than in the managed forest. Regression analyses and DCA revealed the diameter at breast height (dbh) as the most important factor affecting the species diversity and species composition in both forest types. The dbh was positively correlated with the number of growth anomalies and with the bark roughness of the phorophytes and thus a good indicator for the habitat quality. Moreover, the light conditions had a significant impact on the species composition in both forests types and on the species diversity in the managed forest. In particular, epiphytes demanding shady conditions and a consistent humidity may suffer from the abrupt exposition to radiation and the lower humidity after logging. Species typical for the unmanaged forest and most rare species must be considered as stenoecious as they demand the shady and humid conditions of the forest interior and grow on old, large trees. With the aim of sustaining the diversity of epiphytic bryophytes and lichens, forest management should ensure the continuous occurrence of big trees above the target diameter. In addition, a single tree selection felling method should be applied to minimise strong changes in the microclimate. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Variability of male cones in Chamaecyparis as an example for Cupressaceae male cones
Authors: Schulz C. , Stützel Th. 
Published: May 2006

AbstractIn contrast to flowers of other seed plants, male cones in Cupressaceae show a high intraspecific variability regarding the number of scales per cone and the number of pollen sacs per scale. This is the first time a qualitative and quantitative analysis of this variability is given. The variability is shown in distinct patterns. A typical pattern or diagram can be gathered from the analyses of 30 cones, which illustrate the “normal” situation and the most frequent variability (average cone diagram). However, the overlapping intersections in the cone diagrams between the species do however not allow identifications based on single male cones. A detailed study of all five species of Chamaecyparis shows that all of them can be distinguished on the basis of their average male cone diagram. A principal component analysis shows that these five Chamaecyparis species form distinct clusters. Sample cones from different positions of the tree reveal no effect within the variability of the cone diagrams. In contrast, comparison between the species and its cultivars reveals a higher variability in cultivars. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Are population sizes of Campanula glomerata on the decline following the abandonment of traditional land‐use practices?
Authors: Bachmann U. , Hensen I. 
Published: May 2006

AbstractIn Central Germany, many species are known to decline due to the abandonment of traditional land use practices, among them Campanula glomerata . Within the scope of a population viability analysis for this species we monitored the development of several population size parameters such as total number of stems, number of flowering stems, population density and the area occupied by a population, all in landscapes defined by traditional land use practices as well as in landscapes where land use has been halted. However, over a time span of three years we did not detect any constant tendency for decreasing sizes of populations of C. glomerata on disused land compared to those on traditionally used land. Populations in used and abandoned landscapes were characterized by a high variability and fluctuation of size, and did not differ in any of the size parameters we determined. Further studies should include the monitoring of the age state structure of populations as important to facilitate a meaningful comparison of C. glomerata populations in abandoned and traditionally used landscapes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Taxonomic studies of the species of Turbinaria (Fucales, Phaeophyta) from South India
Authors: Sophiammal Nettar P. , Panikkar M. V. N. 
Published: May 2006

AbstractThe taxonomic studies of seven taxa of Turbinaria , collected from different parts of South India are presented. The taxa include three species [T. conoides (J. Agardh) Kützing, T. decurrens Bory, and T. ornata (Turner) J.Agardh] and four forms [T. conoides f. laticuspidata W.R.Taylor, T. ornata f. evesiculosa (Barton) W.R.Taylor, T. ornata f. hainanensis W.R.Taylor and T. ornata f. krishnamurthii f. nova Sophiammal & Panikkar]. Out of these seven taxa, T. ornata (Turner) J.Agardh f. hainanensis W.R.Taylor is a new report to India and T. ornata (Turner) J.Agardh f. krishnamurthii is a new addition to Indian marine flora. All the collected taxa were screened for their morphological characters and the identification was based on the general shape, branching pattern, shape, size and arrangement of the laterals (‘leaves’), size of the vesicles and the occurrence and orientation of the spines. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)