bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential polymorphism in cutaneous glands of archaic Leiopelma species
Authors: Melzer Sabine , Clerens Stefan , Bishop Phillip J. 
Published: June 2011

AbstractEndemic New Zealand frogs of the genus Leiopelma are from a basal lineage of extant anurans that release defensive secretions onto their skin when disturbed. Here, we characterize the gross anatomy and microscopic structure of the skin of L. archeyi, L. hochstetteri, and L. pakeka using stereoscopic, light and transmission electron microscopy. The terrestrial L. archeyi and L. pakeka possess dimorphic granular glands, categorized as type I and II, based on their frequency and morphological traits, whereas the semi‐aquatic L. hochstetteri lacks type I glands. This is the first report of differential dimorphism in anurans of the same genus. This dimorphism could be interpreted as an adaptation to different physiological or ecological needs of these species. However, species within this ancient genus share similar general gland morphology with other anurans, namely, a secretory unit containing storage granules ensheathed by myoepithelial cells. Type I glands are ellipsoid, large and contain a homogeneous mass of electron‐dense granules (1.8 ± 0.08 μm in diameter). Type II glands are round and contain larger heterogeneous granules (4.06 ± 0.16 μm) of varying densities. Exposure to noradrenaline causes the contraction of myoepithelial cells, resulting in bulk discharge of type I glands through the epidermal duct onto the skin surface. Differential release of secretions from dimorphic glands may be indicative of their functional specialisation in antipredatory or regulative roles. Mass spectrometric techniques were used to de novo sequence peptides present in the skin secretions of Leiopelma species. A total of 30 previously undescribed peptides from Leiopelma species were fully or partially sequenced. These peptides exhibited no similarity to any known compounds. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Characterization of the adhesive areas in Sepia tuberculata (Mollusca, Cephalopoda)
Authors: von Byern Janek , Scott Robyn , Griffiths Charles , Micossi Andrea , Grunwald Ingo , Cyran Norbert 
Published: June 2011

AbstractAdhesion in cephalopods is either mechanical, involving a reduced‐pressure system of the arm and tentacle suckers, or is chemically mediated by special adhesive gland structures (as proposed for Euprymna, Idiosepius, and Nautilus). Four species of Sepia (S. typica, S. papillata, S. pulchra, and S. tuberculata) possess grooved structures on the ventral mantle surface and on the fourth arm pair, which are used to attach mechanically to the substratum. Because these areas are often partly covered with sand or debris, it has been hypothesized that chemical substances were involved in this attachment process. This study provides a histochemical and ultrastructural description of the glandular epithelium in the adhesive area of Sepia tuberculata. Two specific glandular cells (Type 1 and Type 2) are present in the epithelium, which differ clearly in their granule size and cellular structure. The aggregation of both cell types and their simultaneous secretion suggest that the secretions of both cell types work synergistically providing a two‐component adhesive system which supports the primarily mechanical sucker adhesion by making the arm surface sticky. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Sexual, habitat‐constrained and parasite‐induced dimorphism in the shell of a freshwater mussel (Anodonta anatina, Unionidae)
Authors: Zieritz Alexandra , Aldridge David C. 
Published: June 2011

AbstractIntraspecific trends in freshwater mussel (unionoid) shells that are consistently associated with differences in the mussels' sex and/or parasitic infestation can potentially be used to reconstruct sex ratios or parasitic levels of modern and ancient unionoid populations. In contrast to morphological patterns within mammal species, such dimorphic trends within unionoid species are, however, poorly understood. This study investigates, for the first time, to what extent sex, trematode infection and indirect habitat effects determine shell morphology in the freshwater mussel Anodonta anatina. Three of the five study populations displayed significant sexual shell width dimorphism. Here, shells of females were significantly wider than males, probably as a result of altered shell growth to accommodate marsupial gills. In two of these populations, female shells were additionally significantly thinner than those of males, which could be a result of resource depletion by offspring production. Two other A. anatina populations showed no significant dimorphic patterns, and our results indicate that this interpopulational difference in the degree of sexual dimorphism may reflect the overarching effect of habitat on morphology. Thus, populations in the most favourable habitats exhibit faster growth rates, attain larger maximum sizes and produce more offspring, which results in more swollen gills and consequently more inflated shells of gravid females compared to less fecund populations. None of the populations showed any evidence for sexual dimorphism in overall size, growth rate, sagittal shape and density of shells. In addition to sexual dimorphisms, infestation by bucephalid trematode parasites (Rhipidocotyle sp.) significantly altered sagittal and lateral shell shape of A. anatina in one of the populations, with infected specimens growing wider and more elongated. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Slit‐Robo signals regulate pioneer axon pathfinding of the tract of the postoptic commissure in the mammalian forebrain
Authors: Ricaño‐Cornejo Itzel , Altick Amy L. , García‐Peña Claudia M. , Nural Hikmet Feyza , Echevarría Diego , Miquelajáuregui Amaya , Mastick Grant S. , Varela‐Echavarría Alfredo 
Published: June 2011

AbstractDuring early vertebrate forebrain development, pioneer axons establish a symmetrical scaffold descending longitudinally through the rostral forebrain, thus forming the tract of the postoptic commissure (TPOC). In mouse embryos, this tract begins to appear at embryonic day 9.5 (E9.5) as a bundle of axons tightly constrained at a specific dorsoventral level. We have characterized the participation of the Slit chemorepellants and their Robo receptors in the control of TPOC axon projection. In E9.5–E11.5 mouse embryos, Robo1 and Robo2 are expressed in the nucleus origin of the TPOC (nTPOC), and Slit expression domains flank the TPOC trajectory. These findings suggested that these proteins are important factors in the dorsoventral positioning of the TPOC axons. Consistently with this role, Slit2 inhibited TPOC axon growth in collagen gel cultures, and interfering with Robo function in cultured embryos induced projection errors in TPOC axons. Moreover, absence of both Slit1 and Slit2 or Robo1 and Robo2 in mutant mouse embryos revealed aberrant TPOC trajectories, resulting in abnormal spreading of the tract and misprojections into both ventral and dorsal tissues. These results reveal that Slit‐Robo signaling regulates the dorsoventral position of this pioneer tract in the developing forebrain. © 2011 Wiley‐Liss, Inc.
Alterations of overused supraspinatus tendon: A possible role of glycosaminoglycans and HARP/pleiotrophin in early tendon pathology
Authors: Attia Mohamed , Scott Alexander , Duchesnay Arlette , Carpentier Gilles , Soslowsky Louis J. , Huynh Minh Bao , Van Kuppevelt Toin H. , Gossard Camille , Courty José , Tassoni Marie‐Claude , Martelly Isabelle 
Published: June 2011

AbstractSupraspinatus tendon overuse injuries lead to significant pain and disability in athletes and workers. Despite the prevalence and high social cost of these injuries, the early pathological events are not well known. We analyzed the potential relation between glycosaminoglycan (GAG) composition and phenotypic cellular alteration using a rat model of rotator cuff overuse. Total sulfated GAGs increased after 4 weeks of overuse and remained elevated up to 16 weeks. GAG accumulation was preceded by up‐regulation of decorin, versican, and aggrecan proteoglycans (PGs) mRNAs and proteins and biglycan PG mRNA after 2 weeks. At 2 weeks, collagen 1 transcript decreased whereas mRNAs for collagen 2, collagen 3, collagen 6, and the transcription factor Sox9 were increased. Protein levels of heparin affine regulatory peptide (HARP)/pleiotrophin, a cytokine known to regulate developmental chondrocyte formation, were enhanced especially at 4 weeks, without up‐regulation of HARP/pleiotrophin mRNA. Further results suggest that the increased GAGs present in early lesions may sequester HARP/pleiotrophin, which could contribute to a loss of tenocyte's phenotype. All these modifications are characteristic of a shift towards the chondrocyte phenotype. Identification of these early changes in the extra‐cellular matrix may help to prevent the progression of the pathology to more disabling, degenerative alterations. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:61–71, 2012
Intercalation of Mono‐ and Difunctional Azobenzenes as Photoresponsible Guest Molecules into Poly(muconic acid) Host Crystals
Authors: Shimogaki Tomoyo , Oshita Shinya , Matsumoto Akikazu 
Published: June 2011

AbstractAn intercalation system consisting of layered PMA crystals as the host material and amino‐functionalized azobenzene derivatives as the guests is studied. The intercalation of difunctional guest molecules yields low conversions compared to the intercalation results using the corresponding monofunctional guests. Investigation of thecis–transphotoisomerization of the intercalated azo compounds reveals that the isomerization rate depends on the packing structure and the mobility of the azobenzene moieties in the host crystals. The monofunctional azobenzene moieties with a longer alkyl spacer undergo fast and reversible photoisomerization. XRD and UV results reveal the arrangement of the guest molecules present in the interlayer space of the host PMA crystals.magnified image
Novel Synthesis of Polycarbazole–Gold Nanocomposite
Authors: Gupta Bhavana , Joshi Leela , Prakash Rajiv 
Published: June 2011

AbstractA polycarbazole–gold nanocomposite is synthesized based on two polymerization techniques, i.e., emulsion and interfacial using aqueous gold chloride and non‐aqueous carbazole monomer solutions. Use of gold chloride as an oxidant for carbazole not only provides a new chemical synthesis for polycarbazole conducting polymer but also allows the formation of conducting nanocomposite in one simple step. Polymerization of carbazole and further growth of the polymer along with gold nanoparticles are governed by the redox reaction between carbazole and Au cations. Two different morphologies of polymers and two different sizes (with narrow size distribution) of gold nanoparticles are obtained depending on the polymerization routes. Structural and thermal properties of the nanocomposites are studied using SEM/TEM, FT‐IR, XRD, and TGA. XRD of nanocomposites depicts the amorphous nature of the polymer and the highly phase selective crystalline nature of gold. Nanocomposites with improved properties show better dispersion in common organic solvents and potential for various technological applications. magnified image
Investigation of Hydrogen Bonded Interpolymer Complexes Based on Poly (n‐butyl methacrylate–co‐methacrylic acid) and Poly (n‐butyl methacrylate ‐co‐4‐vinyl pyridine). Temperature Effect
Authors: Metref Farid , Djadoun Said 
Published: June 2011

AbstractSummary: Two kinds of interpolymer complexes as soluble or precipitate of different structures were obtained in both THF and butan‐2‐one as common solvents by monitoring the hydrogen‐bonding density within homoblends of poly(n‐butyl methacrylate‐co‐4‐vinylpyridine) (BM4VP) and poly(n‐butyl methacrylate‐co‐methacrylic acid) (BMMA). A viscometry study confirmed such differences between these two types of interpolymer complexes from the behavior of the reduced viscosity of their blend solutions with feed blend composition. Qualitative and quantitative analyses of the interactions that occurred between these copolymers of relatively bulky side chain length containing various amounts of methacrylic acid and 4‐vinylpyridine were carried out by FTIR. The fraction of associated pyridine groups to the carboxylic groups of the BMMA increases as the content of these latter increases in the BMMA/BM4VP blends. The obtained results also showed that the fractions of associated pyridine within the BMMA25/BM4VP26 blends are higher than those within BMMA18/BM4VP19 or BMMA8/BM4VP10. The FTIR analysis of a selected BMMA18/BM4VP19 1:1 ratio, carried out from 80 °C to 160 °C, above the glass transition temperatures of the two constituents of the blend, confirms the presence of strong hydrogen bonding interactions between the pyridine and the carboxylic groups within these blends even at 160 °C. A LCST is expected to occur at higher temperature as shown from the progressive decrease of the fraction of the associated pyridine.
Sorption of Pollutant Traces by Nanoporous Crystalline Aerogels: Visualization by a Dye
Authors: Daniel Christophe , Bernardo Fabio 
Published: June 2011

AbstractSummary: The influence of the crystalline structure on the pollutant sorption properties of high porosity syndiotactic polystyrene (sPS) aerogels has been made visible by using azulene, a blue dye, capable to form a clathrate phase with sPS. The bluish coloration observed for aerogels with the nanoporous δ‐form and the absence of coloration for aerogels with the densely‐packed γ‐form clearly establish that the crystalline nanopores play a key role for the removal of pollutant traces from water or air.
Polymer Complexes with Congruent and Incongruent Fusion by Spin Coating
Authors: Richard‐Lacroix Marie , Pellerin Christian 
Published: June 2011

AbstractSummary: We demonstrate that spin coating is an efficient method for preparing pure complexes between polymers and small molecules. Samples of the α and β complexes between poly(ethylene oxide) and urea were prepared as proof‐of‐concept examples since they show congruent and incongruent fusion, respectively. Infrared spectroscopy showed that pure complex of both types could be obtained by spin coating from solutions in various solvents. The ultrafast solvent evaporation appears to be the key factor in preventing the crystallization of the small molecule. These results suggest that this simple method could be generally applicable to a wide range of systems.
Supramolecular Complex of Poly(styrene)‐b‐Poly(4‐vinylpyridine) and 1‐Pyrenebutyric Acid in Thin Film
Authors: Kuila Biplab K. , Stamm Manfred 
Published: June 2011

AbstractSummary:Here, we have described a novel supramolecular complex (SMC) between poly(styrene)‐b‐poly(4‐vinylpyridine) (PS‐b‐P4VP) and 1‐pyrenebutyric acid (PBA) and studied of its self assembly in thin film. PBA will make supramolecular complex with the P4VP block due to strong hydrogen bonding between the carboxylic group of 1‐pyrenebutyric acid and pyridine ring of P4VP. The formation of supramolecular complex between PS‐P4VP and PBA through hydrogen bonding is investigated through FTIR study. The supramolecular complex of PS‐b‐P4VP and 1‐pyrenebutyric acid changed the block copolymer morphology from cylindrical to lamella in thin film due to the increase of the volume fraction of P4VP (PBA). In both cases (parent block copolymer and SMC), the microdomains are oriented normal to the substrate after annealing in a selective solvent. Pure block copolymer shows cylindrical morphology with a periodicity of ∼26 nm, whereas the SMC shows lamellar morphology with a periodicity of ∼ 29 nm. After fabricating the thin film from SMC, 1‐pyrenebutyric acid can be easily removed by dissolving the thin film in ethanol to transform the block copolymer thin film into nanotemplate or membrane.
Equilibrium Phase Diagrams of Interpenetrating Polymer Networks and Liquid Crystals
Authors: Boudraa Kamel , Bouchaour Tewfik , Maschke Ulrich 
Published: June 2011

AbstractSummary: Swelling and deswelling of photochemically crosslinked interpenetrating polymer networks in anisotropic solvents were examined. Phase diagrams were established in terms of composition and temperature using two low‐molecular‐weight nematic liquid crystals, 4‐cyano‐4‐n'‐pentylbiphenyl and an eutectic mixture of cyanoparaphenylenes. Networks were formed by ultraviolet curing in the presence of a difunctional monomer and a photoinitiator. Immersion in excess of solvent allowed us to measure the solvent uptake by weight and to determine the size increase by optical microscopy in terms of temperature. We calculated weight and diameter ratios considering the swollen‐to‐dry network states of the samples.
Optical and Calorimetrical Studies of Liquid Crystalline Materials Doped with Nanoparticles
Authors: Elouali Malika , Beyens Christophe , Elouali Fatima Zohra , Yaroshchuk Oleg , Abbar Boucif , Maschke Ulrich 
Published: June 2011

AbstractSummary: Electro‐optical properties of Polymer Dispersed Liquid Crystal (PDLC) films doped with different nanoparticles (NPs), as well as optical and morphological properties of liquid crystal/NP mixtures have been investigated. PDLC films were prepared by UV irradiation of thiol‐ene monomers and liquid crystal E7 in the presence of a small amount (0.5 and 1 wt.%) of nanoparticles. The presence of NP strongly influence the properties of liquid crystal/NP mixtures. In particular, adding nanoparticles results in a decrease of the glass and nematic‐isotropic transition temperatures of the LC, suggesting that strong interactions occur between LC and nanoparticles.
Characterization and subcellular localization of Tektin 3 in rat spermatozoa
Authors: Takiguchi Hiroe , Murayama Emi , Kaneko Takane , Kurio Hitoshi , Toshimori Kiyotaka , Iida Hiroshi 
Published: June 2011

AbstractMammalian sperm flagella have filament‐forming Tektin proteins (Tektin 1–5) reported to be involved in the stability and structural complexity of flagella. Male mice null for Tektin3 produce spermatozoa with reduced forward progression and increased flagellar structural bending defects. The subcellular localization of Tektin3 (TEKT3) in spermatozoa, however, has not been clarified at the ultrastructural level. To elucidate the molecular localization of TEKT3 in flagella of rat spermatozoa, we performed extraction studies followed by immunoblot analysis, immunofluorescence microscopy, and immunogold electron microscopy. Extraction of sperm flagella from the cauda epididymis resulted in complete removal of axonemal tubulins, while TEKT3 was resistant to extraction with the same S‐EDTA (1% SDS, 75 mM NaCl, 24 mM EDTA, pH 7.6) solution, suggesting that TEKT3 might be present in the peri‐axonemal component and not directly associated with axonemal tubulins. Resistance to S‐EDTA extraction might be due to disulfide bond formation during epididymal maturation since concentrations of DTT greater than 5 mM drastically promoted release of TEKT3 from flagella. Immunofluorescence microscopy and pre‐embedding immunoelectron microscopy revealed that TEKT3 was predominantly associated with the surface of mitochondria and outer dense fibers in the middle piece. In addition, TEKT3 was found to be present at the equatorial segment region of the acrosome membrane in sperm heads. TEKT3 might not only work as a flagellar constituent required for flagellar stability and sperm motility but also may be involved in acrosome‐related events, such as the acrosome reaction or sperm–egg fusion. Mol. Reprod. Dev. 78:611–620, 2011. © 2011 Wiley‐Liss, Inc.
Fast CPMG‐based Bloch‐Siegert B1+ mapping
Authors: Basse‐Lüsebrink T. C. , Sturm V. J. F. , Kampf T. , Stoll G. , Jakob P. M. 
Published: June 2011

AbstractA novel method for B mapping based on the Bloch‐Siegert (BS) shift was recently presented. This method applies off‐resonant pulses before signal acquisition to encode B1 information into the signal phase. BS‐based methods possess significant advantages in measurement time and accuracy compared to magnitude‐based B methods. This study extends the idea of BS B mapping to Carr, Purcell, Meiboom, Gill (CPMG)‐based multi‐spin‐echo (BS‐CPMG‐MSE) and turbo‐spin‐echo (BS‐CPMG‐TSE) imaging. Compared to BS‐based spin echo imaging (BS‐SE), faster acquisition of the B information was possible using the BS‐CPMG‐TSE sequence. Furthermore, signal loss by T2* effects could be minimized using these spin echo‐based techniques. These effects are critical for gradient echo‐based BS methods at high field strengths. However, multi‐spin‐echo‐based BS B1 methods inherently possess high specific absorption rates. Thus, the relative specific absorption rate of BS‐CPMG‐TSE sequences was estimated and compared with the specific absorption rate produced by BS‐SE sequences. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Efficient sample density estimation by combining gridding and an optimized kernel
Authors: Zwart Nicholas R. , Johnson Kenneth O. , Pipe James G. 
Published: June 2011

AbstractThe reconstruction of non‐Cartesian k‐space trajectories often requires the estimation of nonuniform sampling density. Particularly for 3D, this calculation can be computationally expensive. The method proposed in this work combines an iterative algorithm previously proposed by Pipe and Menon (Magn Reson Med 1999;41:179–186) with the optimal kernel design previously proposed by Johnson and Pipe (Magn Reson Med 2009;61:439–447). The proposed method shows substantial time reductions in estimating the densities of center‐out trajectories, when compared with that of Johnson. It is demonstrated that, depending on the trajectory, the proposed method can provide reductions in execution time by factors of 12 to 85. The method is also shown to be robust in areas of high trajectory overlap, when compared with two analytical density estimation methods, producing a 10‐fold increase in accuracy in one case. Initial conditions allow the proposed method to converge in fewer iterations and are shown to be flexible in terms of the accuracy of information supplied. The proposed method is not only one of the fastest and most accurate algorithms, it is also completely generic, allowing any arbitrary trajectory to be density compensated extemporaneously. The proposed method is also simple and can be implemented on parallel computing platforms in a straightforward manner. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.