bluuebunny/crossref_metadata_2025_split huggingface dataset:
Living in forest fragments reduces group cohesion in diademed sifakas (Propithecus diadema) in eastern Madagascar by reducing food patch size
Authors: Irwin Mitchell T. 
Published: December 2006

AbstractForest fragmentation is thought to threaten primate populations, yet the mechanisms by which this occurs remain largely unknown. However, fragmentation is known to cause dietary shifts in several primate species, and links between food resource distribution and within‐group spatial dynamics are well documented. Thus, fragmentation has the potential to indirectly affect spatial dynamics, and these changes may present additional stresses to fragmented populations. I present the results from a 12‐month study of Propithecus diadema at Tsinjoarivo, eastern Madagascar, including two groups in fragments and two in continuous forest. Instantaneous data on activity and spatial position were collected during all‐day focal animal follows. Fragment groups had much lower cohesion, being more likely to have no neighbor within 5 and 10 m. For continuous forest groups, cohesion was highest in the rainy season (when food patches are large) and lowest in winter (when the animals rely on small‐crowned mistletoes), and the chance of having no neighbor within 5 m was positively correlated with mistletoe consumption. Thus their decreased cohesion in fragment groups is inferred to result from their increased reliance on mistletoes and other small resources, which causes them to spread out among multiple patches. This scenario is consistent with the reduced body mass of subordinate individuals (males and immatures) in fragments, and suggests the occurrence of steeper within‐group fitness gradients. Further research is necessary to determine whether these patterns apply to other primates; however, since fragmentation tends to cause the loss of the largest trees, many primates in fragments may lose their largest food resources and undergo similar behavioral shifts. Am. J. Primatol. 69:1–14, 2007. © 2006 Wiley‐Liss, Inc.
Photoluminescence and Conductivity of Self‐Assembled π–π Stacks of Perylene Bisimide Dyes
Authors: Chen Zhijian , Stepanenko Vladimir , Dehm Volker , Prins Paulette , Siebbeles Laurens D. A. , Seibt Joachim , Marquetand Philipp , Engel Volker , Würthner Frank 
Published: December 2006

AbstractThe self‐assembly of a new, highly fluorescent perylene bisimide dye 2 into π stacks, both in solution and condensed phase, has been studied in detail by NMR spectroscopy, vapor pressure osmometry (VPO), UV/Vis and fluorescence spectroscopy, differential scanning calorimetry (DSC), optical polarizing microscopy (OPM) and X‐ray diffraction. The NMR and VPO measurements revealed the formation of extended π–π stacks of the dye molecules in solution. The aggregate size determined from VPO and DOSY NMR measurements agree well with that obtained from the concentration and temperature‐dependent UV/Vis spectral data by employing the isodesmic model (equal K model). In the condensed state, dye 2 possesses a hexagonal columnar liquid crystalline (LC) phase as confirmed by X‐ray diffraction analysis. The columnar stacking of this dye has been further explored by atomic force microscopy (AFM). Well‐resolved columnar nanostructures of the compound are observed on graphite surface. A color‐tunable luminescence from green to red has been observed upon aggregation which is accompanied by an increase of the fluorescence lifetime and depolarization. The observed absorption properties can be explained in terms of molecular exciton theory. The charge transport properties of dye 2 have been investigated by pulse radiolysis‐time resolved microwave conductivity measurements and a 1D charge carrier mobility up to 0.42 cm2 V−1 s−1 is obtained. Considering the promising self‐assembly, semiconducting, and luminescence properties of this dye, it might serve as a useful functional material for nano(opto)electronics.
Importance of Interfacial Adsorption in the Biphasic Hydroformylation of Higher Olefins Promoted by Cyclodextrins: A Molecular Dynamics Study at the Decene/Water Interface
Authors: Sieffert Nicolas , Wipff Georges 
Published: December 2006

AbstractWe report herein a molecular dynamics study of the main species involved in the hydroformylation of higher olefins promoted by cyclodextrins in 1‐decene/water biphasic systems at a temperature of 350 K. The two liquids form a well‐defined sharp interface of approximately 7 Å width in the absence of solute; the decene molecules are generally oriented “parallel” to the interface where they display transient contacts with water. We first focused on rhodium complexes bearing water‐soluble TPPTS3− ligands (where TPPTS3− represents tris(m‐sulfonatophenyl)phosphine) involved in the early steps of the reaction. The most important finding concerned the surface activity of the “active” form of the catalyst [RhH(CO)(TPPTS)2]6−, the [RhH(CO)2(TPPTS)2]6− complex, and the key reaction intermediate [RhH(CO)(TPPTS)2(decene)]6− (with the olefin π‐coordinated to the metal center) which are adsorbed at the water side of the interface in spite of their −6 charge. The free TPPTS3− ligands themselves are also surface‐active, whereas the −9 charged catalyst precursor [RhH(CO)(TPPTS)3]9− prefers to be solubilized in water. The role of cyclodextrins was then investigated by performing simulations on 2,6‐dimethyl‐β‐cyclodextrin (“CD”) and its inclusion complexes with the reactant (1‐decene), a reaction product (undecanal), and the corresponding key reaction intermediate [RhH(CO)(TPPTS)2(decene)]6− as guests; they were all shown to be surface‐active and prefer the interface over the bulk aqueous phase. These results suggest that the biphasic hydroformylation of higher olefins takes place “right” at the interface and that the CDs promote the “meeting” of the olefin and the catalyst in this peculiar region of the solution by forming inclusion complexes “preorganized” for the reaction. Our results thus point to the importance of adsorption at the liquid/liquid interface in this important phase‐transfer‐catalyzed reaction.
Host‐Guest Interactions between N,N′‐Bis(ferrocenylmethylene)‐Diaminobutane and Benzenetetracarboxylic Dianhydride Bridged Bis(β‐cyclodextrin)s
Authors: Chen Xi , Liu Jing , Yan Jun‐Lin , Fang Yu 
Published: December 2006

AbstractA novel water soluble ditopic guest, the quaternary ammonium salt of N,N′‐bis(ferrocenylmethylene)‐diami‐ nobutane (1), and a known water soluble ditopic host, benzenetetracarboxylic dianhydride bridged bis(β‐cyclo‐dextrin)s (2), have been synthesized and characterized. 1H NMR spectra and cyclic voltammogram (CV) studies revealed the host‐guest interactions between them in aqueous solution. The supramolecular interaction also exists in solid state as confirmed by the studies of the solid samples, which were obtained by frozen‐drying the solution samples, using FTIR spectroscopy and differential scanning calorimetry (DSC) techniques. TEM measurement demonstrated that wire‐shaped supramolecular aggregates exist in the aqueous solution of the two compounds. The lengths of the aggregates could reach micrometers.
Alkylation of Hydroquinone with tert‐Butyl Alcohol over Bis[(perfluoroalkyl)sulfonyl]imides Supported on MCM‐41
Authors: Yuan Yu‐Bin , Nie Jin , Zhang Zheng‐Bo , Zhou San‐Yi 
Published: December 2006

AbstractBis[(perfluoroalkyl)sulfonyl]imides [HN(SO2Rf)2, and Rf represents the perfluorinated alkyl group] supported on MCM‐41 were synthesized and characterized by XRD, FTIR, SEM, TGA and N2‐adsorption techniques. The supported catalysts, HN(SO2Rf)2/MCM‐41, were used as the catalysts for the tert‐butylation of hydroquinone (HQ) with tert‐butyl alcohol (TBA) in the liquid phase. A high yield (52.0%) of 2‐tert‐butyl hydroquinone (TBHQ) could be obtained in the presence of 5 mol% HN(SO2C4F9)2/MCM‐41 under the optimized reaction conditions and the heterogeneous catalyst could be recycled at least 6 times without substantial loss of activity.
Construction of a Novel 2D Polymer [Co(dmpzm)(dca)2]∞ from Reaction of a Mononuclear Complex [Co(dmpzm)Cl2] with Sodium Dicyanamide (dca) [dmpzm=bis(3,5‐dimethylpyrazolyl)methane]
Authors: Li Qiao‐Yun , Zhang Wen‐Hua , Li Hong‐Xi , Tang Xiao‐Yan , Lang Jian‐Ping , Zhang Yong , Wang Xin‐Yi , Gao Song 
Published: December 2006

AbstractReaction of CoCl2·6H2O with equimolar bis(3,5‐dimethylpyrazolyl)methane (dmpzm) produced a mononuclear adduct [Co(dmpzm)Cl2] (1). Treatment of 1 with sodium dicyanamide (dca) afforded a polymeric complex [Co(dmpzm)(μ‐dca)2]∞ (2). 1 and 2 were characterized by elemental analysis, IR spectra, thermogravimetric analysis and single‐crystal X‐ray diffraction. The cobalt atom in 1 adopts a distorted tetrahedral coordination geometry, bound to two N atoms of one dmpzm and two Cl atoms. Complex 2 has a 2D brick‐wall network (extended along the bc plane) in which the {[Co(dmpzm)(μ‐dca)]2}2n+n chains are interconnected by pairs of μ‐dca anions along the c axis. The magnetic properties of 1 and 2 were also investigated.
Synthesis and Crystal Structure of Two iso‐closo 11‐Vertex p‐Bromobenzoate Ruthenoborane Clusters: [(PPh3)(p‐BrC6H4CO2)2RuB10H8] and [(PPh3)2Ru(p‐BrC6H4CO2)‐(PPh3)RuB10H9]
Authors: Guo Qing‐Liang , Dou Jian‐Min , Wu Li‐Bin , Li Da‐Cheng , Wang Da‐Qi 
Published: December 2006

AbstractThe title clusters [(PPh3)(p‐BrC6H4CO2)2RuB10H8] (1) and [(PPh3)2Ru(PPh3)(p‐BrC6H4CO2)RuB10H9] (2) have been prepared and characterized by elemental analysis, FT‐IR, 1H, 13C NMR spectra and single‐crystal X‐ray diffraction analysis. The clusters crystallize in monoclinic system, space group C2/c, with a=2.569(4) nm, b=1.546(2) nm, c=1.927(3) nm, β=95.11(2)°, Z=8, V=7.622(21) nm3, Dc=1.533 Mg/m3, F(000)=3472, S=1.009, R=0.0418, wR=0.0775 and triclinic system, space group P‐1, with a=1.3142(3) nm, b=1.3761(3) nm, c=1.8503(4) nm, α=90.445(4)°, β=105.950(4)°, (=108.980(4)°, Z=2, V=3.0251(12) nm3, Dc=1.434 Mg/m3, F(000)=1316, S=1.007, R=0.0464, wR=0.1175, respectively for 1 and 2. In the structures, both of the clusters are based on a closo‐type C2v 1:2:4:2:2 RuB10 stack with the metal occupying the unique six‐connected apical position. In cluster 1, the metal center has three exo‐polyhedral ligands:one triphenylphosphine and two dative oxygen atoms of p‐bromobenzoates. The other oxygen atoms of two p‐bromobenzoate are additionally bonded to B(2) and B(3) atoms respectively, resulting in two exo‐cyclic five‐membered Ru‐O‐C‐O‐B rings and engendering a symmetrical conformation. The cluster 2 is a bimetallic species in which the second ruthenium is bound to the {RuB10} center via one Ru–Ru bond and two {RuHµB} bridges resulting in one closo distorted exo‐polyhedral Ru(1)‐ Ru(2)‐B(3)‐B(6) tetrahedron.
Comparison of 2D Fingerprint Methods for Multiple‐Template Similarity Searching on Compound Activity Classes of Increasing Structural Diversity
Authors: Tovar Andrea , Eckert Hanna , Bajorath Jürgen 
Published: December 2006

AbstractWe studied the similarity search performance of differently designed molecular fingerprints using multiple reference structures and different search strategies. For this purpose, nine compound activity classes were assembled that exclusively consisted of molecules with different core structures and that represented different levels of intra‐class structural diversity. Thus, there was a strict one‐to‐one correspondence between test compounds and core structures. Analysis of unique core structures was found to be a better measure of class diversity than distributions of simplified scaffolds. On increasingly diverse classes, a trainable fingerprint using a unique search strategy performed better than others tested herein. Overall, clear preferences were detected for nearest‐neighbor search strategies over fingerprint‐averaging techniques. Nearest‐neighbor searching that relied on selecting database compounds most similar to one of the reference structures often improved compound recovery over other averaging methods, but at the cost of decreasing the ability to detect hits that were structurally distinct from reference molecules.
The impact of factors beyond Breslow depth on predicting sentinel lymph node positivity in melanoma
Authors: Paek Sandra C. , Griffith Kent A. , Johnson Timothy M. , Sondak Vernon K. , Wong Sandra L. , Chang Alfred E. , Cimmino Vincent M. , Lowe Lori , Bradford Carol R. , Rees Riley S. , Sabel Michael S. 
Published: December 2006

AbstractBACKGROUND.In addition to Breslow depth, the authors previously described how increasing mitotic rate and decreasing age predicted sentinel lymph node (SLN) metastases in patients with melanoma. The objectives of the current study were to verify those previous results and to create a prediction model for the better selection of which patients with melanoma should undergo SLN biopsy.METHODS.The authors reviewed 1130 consecutive patients with melanoma in a prospective database who underwent successful SLN biopsy. After eliminating patients aged <16 years and patients who had melanomas that measured <1 mm, 910 remaining patients were reviewed for clinical and pathologic features and positive SLN status. Univariate association of patient and tumor characteristics with positive SLN status was explored by using standard logistic regression techniques, and the best multivariate model that predicted lymph node metastases was constructed by using a backward stepwise‐elimination technique.RESULTS.The characteristics that were associated significantly with lymph node metastasis were angiolymphatic invasion, the absence of regression, increasing mitotic rate, satellitosis, ulceration, increasing Breslow depth, decreasing age, and location (trunk or lower extremity compared with upper extremity or head/neck). Previously reported interactions between mitotic rate and age and between Breslow depth and age were confirmed. The best multivariate model included patient age (linear), angiolymphatic invasion, the number of mitoses (linear), the interaction between patient age and the number of mitoses, Breslow depth (linear), the interaction between patient age and Breslow depth, and primary tumor location.CONCLUSIONS.Younger age, increasing mitotic rate (especially in younger patients), increasing Breslow depth (especially in older patients), angiolymphatic invasion, and trunk or lower extremity location of the primary tumor were associated with a greater likelihood of positive SLN status. The current results support the use of factors beyond Breslow depth to determine the risk of positive SLN status in patients with cutaneous melanoma. Cancer 2007. © 2006 American Cancer Society
Myoblast fusion in Drosophila melanogaster is mediated through a fusion‐restricted myogenic‐adhesive structure (FuRMAS)
Authors: Kesper Dörthe Andrea , Stute Christiana , Buttgereit Detlev , Kreisköther Nina , Vishnu Smitha , Fischbach Karl‐Friedrich , Renkawitz‐Pohl Renate 
Published: December 2006

AbstractDuring myogenesis in Drosophila embryos, a prominent adhesive structure is formed between precursor cells and fusion‐competent myoblasts (fcms). Here, we show that Duf/Kirre and its interaction partners Rols7 (found in founder myoblasts and growing myotubes) and Sns (found in fcms) are organized in a ring‐structure at the contact points of fcms with precursor cells, while cytoskeletal components like F‐actin and Titin are centered in this ring in both cell types. The cytoplasmic protein Blow colocalizes with the actin plugs in fcms after cell adhesion. Furthermore, the requirement of additional as yet unidentified components was demonstrated by using mammalian C2C12 myoblasts. In this study, we propose that the fusion‐restricted myogenic‐adhesive structure (FuRMAS) is pivotal in linking cell adhesion as well as local F‐actin assembly and dynamics to downstream events that ultimately lead to plasma membrane fusion. Moreover, we suggest that the FuRMAS may restrict the area of membrane breakdown. Developmental Dynamics 236:404–415, 2007. © 2006 Wiley‐Liss, Inc.
Syntheses, Characterization and Reactivity of Iron(II), Nickel(II), Copper(II) and Zinc(II) Complexes of the Ligand N,N,N′,N′‐Tetrakis(2‐pyridylmethyl)benzene‐1,3‐diamine (1,3‐tpbd) and Its Phenol Derivative 2,6‐Bis[bis(2‐pyridylmethyl)amino]‐p‐cresol (2,6‐tpcd)
Authors: Foxon Simon , Xu Jing‐Yuan , Turba Sabrina , Leibold Michael , Hampel Frank , Heinemann Frank W. , Walter Olaf , Würtele Christian , Holthausen Max , Schindler Siegfried 
Published: December 2006

AbstractN,N,N′,N′‐Tetrakis(2‐pyridylmethyl)benzene‐1,3‐diamine (1,3‐tpbd), a bis(tridentate) ligand, its protonated derivative, [1,3‐tpbdH2]2+, and a series of new dinuclear complexes [Fe2(1,3‐tpbd)(CH3CN)6](ClO4)4·(CH3CN)2·(H2O)0.5 (1), [Fe2(1,3‐tpbd)(DMF)6](ClO4)4 (2), [Ni2(1,3‐tpbd)(DMF)6](ClO4)4 (3), [Zn2(1,3‐tpbd)(CH3CN)2(SO3CF3)2(H2O)](SO3CF3)2 (4), [Zn2(1,3‐tpbd)Cl4]·H2O (5), [CuZn(1,3‐tpbd)Cl4] (7) and the tetranuclear copper(II) complex [Cu2(1,3‐tpbd)2(H2O)2](ClO4)4·2H2O (8) have been prepared and structurally characterized. Complex 8, a so called “dimetallocyclophane”, interestingly only formed in the presence of zinc ions and not when copper(II) ions were mixed stoichiometrically (1:1 mixtures) under aerobic conditions. Theoretical calculations provide evidence for the formation of a side‐on dinuclear peroxido copper complex during the oxidation of the (1,3‐tpbd)copper(I) complex. A possible reaction product, the dinuclear copper complex [Cu2(2,6‐tpcd)(H2O)(Cl)](ClO4)2·2H2O (9) of a phenolate derivative of 1,3‐tpbd was synthesized and structurally characterized independently from oxidation reactions from copper(II) perchlorate and the ligand 2,6‐bis[bis(2‐pyridylmethyl)amino]‐p‐cresol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Hippocampal gene expression analysis using the ORESTES methodology shows that homer 1a mRNA is upregulated in the acute period of the pilocarpine epilepsy model
Authors: Avedissian Marcelo , Longo Beatriz M. , Jaqueta Carolina B. , Schnabel Beatriz , Paiva Paulo B. , Mello Luiz Eugênio A.M. , Briones Marcelo R.S. 
Published: December 2006

AbstractIn the study of temporal lobe epilepsy (TLE) the characterization of genes expressed in the hippocampus is of central importance for understanding their roles in epileptogenic mechanisms. Although several large‐scale studies on TLE gene expression have been reported, precise assignment of individual genes associated with this syndrome is still debatable. Here we investigated differentially expressed genes by comparison of mRNAs from normal and epileptic rat hippocampus in the pilocarpine model of epilepsy. For this we used a powerful EST sequencing methodology, ORESTES (Open Reading frame Expressed Sequence Tags), which generates sequence datasets enriched for mRNAs open reading frames (ORFs) rather than simple 5′ and 3′ ends of mRNAs. Analysis of our sequences shows that ORESTES readily enables the identification of epilepsy associated ORFs. PFAM analysis of protein motifs present in our ORESTES epilepsy database revealed diverse important protein family domains, such as cytoskeletal, cell signaling and protein kinase domains, which could be involved in processes underlying epileptogenesis. More importantly, we show that the expression of homer 1a, known to be coupled to mGluR and NMDA synaptic transmission, is associated with pilocarpine induced status epilepticus (SE). The combined use of the pilocarpine model of epilepsy with the ORESTES technique can significantly contribute to the identification of specific genes and proteins related to TLE. This is the first study applying a large‐scale method for rapid shotgun sequencing directed to ORFs in epilepsy research. © 2006 Wiley‐Liss, Inc.
The homology and phylogeny of chondrichthyan tooth enameloid
Authors: Gillis J. Andrew , Donoghue Philip C.J. 
Published: December 2006

AbstractA systematic SEM survey of tooth microstructure in (primarily) fossil taxa spanning chondrichthyan phylogeny demonstrates the presence of a superficial cap of single crystallite enameloid (SCE) on the teeth of several basal elasmobranchs, as well as on the tooth plates of Helodus (a basal holocephalan). This suggests that the epithelial–mesenchymal interactions required for the development of enameloid during odontogenesis are plesiomorphic in chondrichthyans, and most likely in toothed gnathostomes, and provides phylogenetic support for the homology of chondrichthyan and actinopterygian enameloid. Along the neoselachian stem, we see a crownward progression, possibly modulated by heterochrony, from a monolayer of SCE lacking microstructural differentiation to the complex triple‐layered tooth enameloid fabric of neoselachians. Finally, the occurrence of fully‐differentiated neoselachian enameloid microstructure (including compression‐resistant tangle fibered enameloid and bending‐resistant parallel fibered enameloid) in Chlamydoselachus anguineus, a basal Squalean with teeth that are functionally “cladodont,” is evidence that triple‐layered enameloid microstructure was a preadaption to the cutting and gouging function of many neoselachian teeth, and thus may have played an integral role in the Mesozoic radiation of the neoselachian crown group. J. Morphol, 2006. © 2006 Wiley‐Liss, Inc.
Stability of fused versus nonfused THA Femoral impaction grafts
Authors: Heiner Anneliese D. , Callaghan John J. , Brown Thomas D. 
Published: December 2006

AbstractImpaction grafting for THA involves compacting morselized cancellous bone (MCB) into a cavitary defect to build up bone stock. Ideally, the MCB subsequently remodels into a new contiguous cancellous lattice. A recent laboratory model of MCB fusion allows simulating an impaction graft construct in this ideal eventual clinical state. The purpose of the present study was to determine the relative stability of femoral impaction graft constructs in which the MCB has fused versus that for MCB in the freshly impacted nonfused condition. Cemented femoral impaction graft constructs were created in composite femurs. For fused constructs, the MCB was mixed with an amine epoxy that causes the MCB to set up into a contiguous structure biomechanically comparable to intact cancellous bone in compression. The constructs were loaded with 500,000 physiologic gait cycles. Three‐dimensional motion was measured between the femur and the stem. The fused femoral impaction grafts were much more stable than the nonfused grafts at the proximal stem location, but MCB fusion had only a modest effect on distal stem stability. These results indicate that most of the opportunity to reduce femoral stem micromotion and migration lies proximal, and that steps to enhance impaction graft remodeling and fusion are most effectively focused proximally. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 2007