bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructure of the spermatozoon of the American Alligator, Alligator mississippiensis (Reptilia: Alligatoridae)
Authors: Gribbins Kevin M. , Touzinsky Katherine F. , Siegel Dustin S. , Venable Katherine J. , Hester Georgia L , Elsey Ruth M. 
Published: June 2011

AbstractThis study details the ultrastructure of the spermatozoa of the American Alligator, Alligator mississippiensis. American Alligator spermatozoa are filiform and slightly curved. The acrosome is tapered at its anterior end and surrounded by the acrosome vesicle and an underlying subacrosomal cone, which rests just cephalic to the nuclear rostrum. One endonuclear canal extends from the subacrosomal cone through the rostral nucleus and deep into the nuclear body. The neck region separates the nucleus and midpiece and houses the proximal centriole and pericentriolar material. The distal centriole extends through the midpiece and has 9 × 3 sets of peripheral microtubules with a central doublet pair within the axoneme that is surrounded by a dense sheath. The midpiece is composed of seven to nine rings of mitochondria, which have combinations of concentrically and septate cristae. The principal piece has a dense fibrous sheath that surrounds an axoneme with a 9 + 2 microtubule arrangement. The sheath becomes significantly reduced in size caudally within the principal piece and is completely missing from the endpiece. Dense peripheral fibers, especially those associated with microtubule doublets 3 and 8, penetrate into the anterior portion of the principal piece axoneme. The data reported here hypothesize that sperm morphology is highly conserved in Crocodylia; however, specific morphological differences can exist between species. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
The vascular morphology and in vivo muscle temperatures of thresher sharks (Alopiidae)
Authors: Patterson James C. , Sepulveda, Chugey A. , Bernal Diego 
Published: June 2011

AbstractThe thresher sharks comprise a single family (Alopiidae) of pelagic sharks most easily recognized by the elongate dorsal lobe of their caudal fin. Despite morphological similarities among the alopiids, the common thresher (Alopias vulpinus) is unique in that its red, aerobic myotomal muscle (RM) is medially positioned (i.e., closer to the vertebrae), its systemic blood is supplied through a lateral circulation which give rise to counter‐current heat exchanging retia, and it is capable of regional RM endothermy. Despite this information, it remains unknown if the other two alopiid species (bigeye thresher, Alopias superciliosus and pelagic thresher, Alopias pelagicus) also possess some or all of the characteristics related to regional RM endothermy. Thus, this study aimed to 1) document the presence of vascular specializations necessary for heat retention and RM endothermy and 2) measure the in vivo muscle temperatures of all three alopiid species. Laboratory dissections of the thresher species showed that only A. vulpinus possesses the lateral branching of the dorsal aorta giving rise to a lateral subcutaneous circulation and retial system, and that RM temperatures are elevated relative to ambient temperature. By contrast, both A. pelagicus and A. superciliosus have a similar systemic blood circulation pathway, in which the dorsal aorta and postcardinal vein form the basis for the central circulation and in vivo RM temperature measurements closely matched those of the ambient temperature at which the sharks were captured. Collectively, the vascular anatomy and in vivo temperature data suggest that only one species of thresher shark (A. vulpinus) possesses the requisite vascular specializations (i.e., lateral subcutaneous vessels and retia mirabilia) that facilitate RM endothermy. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
P‐selectin/ligand unbinding force measured with atomic force microscopy: comparison of two chemical protocols for the tethering of single molecules
Authors: Tsapikouni Theodora , Missirlis Yannis F. 
Published: June 2011

AbstractLeukocytes, as an indispensable arm of the immune system, need to be recruited from the flowing blood and transferred to the sites of infection. Their extravasation is feasible due to their ability to tether and roll over the activated endothelium, which is much dependent on the association of their selectin molecules with ligands on the activated endothelial cells. In view of the importance of this interaction for the physiological immune functions as well as for autoimmune diseases, specifying the affinity of selectins to their ligands at the single molecule level appears a challenging task to gain insight into the mechanisms that control leukocyte–endothelial avidity. To this end we functionalized substrates with P‐selectin and cantilever probes with its major ligand, the P‐selectin glycoprotein ligand‐1, and used atomic force microscopy to measure their unbinding force. Two different chemical protocols were used for the tethering of the molecules on the substrates, one based on a homobifunctional poly(ethylene glycol) linker and the other on the use of antibody‐specific binding. The unbinding forces measured with the two methods were 312 ± 149 and 230 ± 57 pN, respectively. Measurements on activated endothelials, declaratory of single molecule interactions, gave comparable results. Copyright © 2011 John Wiley & Sons, Ltd.
Mechanism and thermodynamics of ligand binding to auxin amidohydrolase
Authors: Simunovic Mijo , Zagrovic Bojan , Tomić Sanja 
Published: June 2011

AbstractBrILL2 is catalytically the most efficient auxin amidohydrolase from Brassica rapa, playing a key role in auxin metabolism by catalyzing its release from amino acid conjugates. Auxins, with the most abundant representative indole‐acetic acid ([1H‐indol‐3‐yl]‐acetic acid, IAA), are a group of plant hormones that in very small concentrations regulate ubiquitin‐mediated degradation of transcription regulators. Kinetic studies on BrILL2 showed that it hydrolyzes alanine conjugates of IAA and of its larger analogues, indole‐propionic acid (3‐[1H‐indol‐3‐yl]‐propionic acid, IPA) and indole‐butyric acid (4‐[1H‐indol‐3‐yl]‐butyric acid, IBA). Structurally, BrILL2 belongs to the largest known family of metallopeptidases (M20) that share a recognizable 3D structure, characterized by two perpendicular domains. Its members have been implicated in numerous biochemical processes and have been found across all species sequenced to date. Here, molecular dynamics simulations were carried out to study structural and thermodynamic properties of ligand binding to BrILL2. A conformational change was captured in multiple copies of 10 ns long simulations, described by a rigid body movement of the two domains, and its associated key interactions between residues were examined. For the three substrates, complexes in two possible binding modes were recreated, along with a single binding mode for the putative substrate tryptophanyl–alanine (Trp–Ala), which were subsequently simulated in multiple copies of 10 ns long simulations. Thermodynamic calculations were used to assess their binding affinities and explain the selectivity toward the longer ligands. Based on the results, a possible route for the reaction is proposed. Copyright © 2011 John Wiley & Sons, Ltd.
A deregulated integrated stress response promotes interferon‐γ‐induced medulloblastoma
Authors: Lin Wensheng , Lin Yifeng , Li Jin , Harding Heather P. , Ron David , Jamison Stephanie 
Published: June 2011

AbstractEndoplasmic reticulum (ER) stress activates pancreatic ER kinase (PERK), which coordinates an adaptive program known as the integrated stress response (ISR) by phosphorylating translation initiation factor 2α (eIF2α). There is evidence that the ISR is involved in tumor development. Recent studies also show that the ISR stimulates the expression of vascular endothelial growth factor A (VEGF‐A), a master regulator of angiogenesis. Our previous studies have demonstrated that enforced expression of interferon‐γ (IFNγ) in the central nervous system during development induces sonic hedgehog expression and leads to cerebellar dysplasia or medulloblastoma. Here we report that PERK was activated in cerebellar dysplasia and medulloblastoma in IFNγ‐expressing mice. We found that inactivation of the growth arrest and DNA damage 34 (GADD34) gene, encoding the stress‐inducible regulatory subunit of a phosphatase complex that dephosphorylates eIF2α, enhanced ISR signaling and facilitated medulloblastoma formation in IFNγ‐expressing mice. Moreover, we found that the induction of VEGF‐A and enhanced angiogenesis were associated with medulloblastoma formation in IFNγ‐expressing mice on the GADD34 mutation background. Thus, our data provide genetic evidence that the ISR facilitates modulloblastoma development. © 2011 Wiley‐Liss, Inc.
Modulation of dopamine‐dependent behaviors by the Caenorhabditis elegans Olig homolog HLH‐17
Authors: Felton Chaquettea M. , Johnson Casonya M. 
Published: June 2011

AbstractIn vertebrates and invertebrates, dopamine signaling modulates a wide variety of physical and behavioral functions and exerts these effects through heterotrimeric G proteins. The soil nematode Caenorhabditis elegans has been used to model dopamine signaling and reacts reproducibly to alterations in dopamine levels through eight well‐characterized dopaminergic neurons located in the head. In C. elegans, the basic helix–loop–helix transcription factor HLH‐17 is strongly and constitutively expressed in the glia cells that ensheath four of the dopaminergic neurons, yet it is not required for specification or development of either the glia or the neurons. In this study, we sought to determine whether HLH‐17 functions in dopamine signaling. We found that, unlike wild‐type animals, hlh‐17 animals are resistant to the effects of exogenous dopamine on egg laying and mobility. hlh‐17 animals are also defective in the basal slowing and gustatory plasticity behaviors that require functional dopamine signaling. We also found that the expression of the dopamine receptor genes dop‐1, dop‐2, and dop‐3 and the RGS protein gene egl‐10 is significantly reduced in hlh‐17 animals. Together these results point to a role for HLH‐17 in dopamine signaling in C. elegans. © 2011 Wiley‐Liss, Inc.
Human L1CAM carrying the missense mutations of the fibronectin‐like type III domains is localized in the endoplasmic reticulum and degraded by polyubiquitylation
Authors: Itoh Kouichi , Fujisaki Kanako , Watanabe Masatomo 
Published: June 2011

AbstractAny mutations in the human neural cell adhesion molecule L1 (hL1CAM) gene might cause various types of serious neurological syndromes in humans, characterized by increased mortality, mental retardation, and various malformations of the nervous system. Such missense mutations often cause severe abnormalities or even fatalities, and the reason for this may be a disruption of the adhesive function of L1CAM resulting from a misdirection of the degradative pathway. Transfection studies using neuroblastoma N2a cells demonstrated that hL1CAM carrying the missense mutations in the fibronectin‐like type III (FnIII) domains most likely is located within the endoplasmic reticulum (ER), but it is less well expressed on the cell surface. One mutant, L935P, in the fourth FnIII domain, was chosen from six mutants (K655 and G698 at Fn1, L935P and P941 at Fn4, W1036 and Y1070 at Fn5) in the FnIII domains to study in detail the functions of hL1CAM200kDa, such as the intracellular traffic and degradation, because only a single band at 200 kDa was detected in the hL1CAML935P‐transfected cells. hL1CAM200kDa is expressed predominantly in the ER but not on the cell surface. In addition, this missense mutated hL1CAM200kDa is polyubiquitylated at some sites in the extracellular domain and thus becomes degraded by proteasomes via the ER‐associated degradation pathway. These observations demonstrate that the missense mutations of hL1CAM in the FnIII domain may cause the resultant pathogenesis because of a loss of expression on the cell surface resulting from misrouting to the degradative pathway. © 2011 Wiley‐Liss, Inc.
Impacts of tropical Indian Ocean SST on the meridional displacement of East Asian jet in boreal summer
Authors: Qu Xia , Huang Gang 
Published: June 2011

AbstractThe meridional displacement of East Asia jet (EAJ) is characterized by the leading mode of upper tropospheric zonal wind variability over East Asia in boreal summer, and is closely related to the East Asia summer monsoon and downstream climate. Present study reveals that the meridional displacement of EAJ is associated with tropical Indian Ocean (TIO) SST anomalies. When the TIO SST is higher than normal, the overlying tropospheric air warms up through the modulation of the TIO SST on tropical convection. The anomalous convection forces a Kelvin wave wedge penetrating into the equatorial western Pacific, leading to a decrease in precipitation near the Philippines. Combined with the climatological easterly shear over the subtropical western North Pacific, the Pacific‐Japan/East Asia‐Pacific (PJ/EAP) teleconnection is induced along the East Asia coast. The PJ/EAP‐related upper‐level anomalous cyclone accelerates westerly in the south flank of EAJ and decelerates westerly in the north flank. Thus, EAJ shifts southward. In contrast, the EAJ shifts northward when the TIO SST is lower than normal. Copyright © 2011 Royal Meteorological Society
BMP‐2 mediates PGE2‐induced reduction of proliferation and osteogenic differentiation of human tendon stem cells
Authors: Zhang Jianying , Wang James H‐C. 
Published: June 2011

AbstractTendon stem cells (TSCs) have been proposed to play a major role in the development of tendinopathy, which refers to pathological changes, such as calcification, in affected tendons. Using a human TSC (hTSC) culture model, this study investigated the effects of PGE2, an inflammatory mediator present in injured tendons, on hTSC proliferation and differentiation as well as the molecular mediator for such PGE2‐induced effects. We found that PGE2 treatment of hTSCs decreased cell proliferation and caused osteogenic differentiation of hTSCs in a dose‐dependent manner. Also, PGE2 treatment of hTSCs induced dose‐dependent BMP‐2 production in culture, and moreover, addition of BMP‐2 to hTSC culture decreased cell proliferation and induced hTSC differentiation into osteoblasts. Finally, addition of BMP‐2 antibodies to hTSC culture treated with PGE2 nearly abolished PGE2 effects on both cell proliferation and osteogenic differentiation. Taken together, the findings of this study showed that BMP‐2 mediates PGE2‐induced reduction of proliferation and osteogenic differentiation of hTSCs. We suggest that such a mechanism may be partially responsible for the formation of calcified tissues in tendinopathic tendons seen in clinical settings. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:47–52, 2012
Low intensity pulsed ultrasound enhances fracture healing in both ovariectomy‐induced osteoporotic and age‐matched normal bones
Authors: Cheung Wing‐Hoi , Chin Wai‐Ching , Qin Ling , Leung Kwok‐Sui 
Published: June 2011

AbstractLow intensity pulsed ultrasound (LIPUS) was proven to enhance fracture healing effectively. Similar effect of LIPUS on accelerating the osteoporotic fracture healing was therefore hypothesized. The normal and osteoporotic fracture healings under this non‐invasive biophysical intervention of LIPUS were compared and investigated. Closed femoral fracture procedures were performed on 120 Sprague–Dawley rats, in which 60 of them were ovariectomized (OVX). The rats were randomly assigned into four groups: sham OVX with treatment (Sham‐T), sham OVX control (Sham‐C), OVX with treatment (OVX‐T) and OXV control (OVX‐C). LIPUS treatment was 20 min a day, 5 days a week for durations of 2, 4, or 8 weeks. Results from weekly radiography, histomorphometry, micro‐computed tomography and mechanical test showed both the treatment groups were with better healing responses than their control groups. Moreover, between the normal and the osteoporotic treatment groups, a significantly higher (p = 0.015) callus width (week 4), higher ratio of increment in bone volume to tissue volume ratio value (7.4% more), faster response of endochondral ossification and a higher stiffness measurement were observed in the osteoporotic treatment group. These comparable results on healing responses imply that LIPUS can be applied clinically to enhance both normal and osteoporotic fracture healing. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:129–136, 2012
Dynamics of the CH3 + OH reaction
Authors: Ree J. , Kim Y. H. , Shin H. K. 
Published: June 2011

AbstractWe study dynamics of the CH3 + OH reaction over the temperature range of 300–2500 K using a quasiclassical method for the potential energy composed of explicit forms of short‐range and long‐range interactions. The explicit potential energy used in the study gives minimum energy paths on potential energy surfaces showing barrier heights, channel energies, and van der Waals well, which are consistent with ab initio calculations. Approximately, 20% of CH3 + OH collisions undergo OH dissociation in a direct‐mode mechanism on a subpicosecond scale (<50 fs) with the rate coefficient as high as ∼10−10 cm3 molecule−1 s−1. Less than 10% leads to the formation of excited intermediates CH3OH† with excess vibrational energies in CO and OH bonds. CH3OH† stabilizes to CH3OH, redissociates back to reactants, or forms one of various products after intramolecular energy redistribution via bond dissociation and formation on the time scale of 50–200 fs. The principal product is 1CH2 (k being ∼10−11), whereas ks for CH2OH, CH2O, and CH3O are ∼10−12. The minor products are HCOH and CH4 (k∼10−13). The total rate coefficient for CH3 + OH → CH3OH† → products is ∼10−11 and is weakly dependent on temperature. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 455–466, 2011
Biologically Inspired Hierarchical Design of Nanocomposites Based on Poly(ethylene oxide) and Cellulose Nanofibers
Authors: Changsarn Sutheerat , Mendez James D. , Shanmuganathan Kadhiravan , Foster E. Johan , Weder Christoph , Supaphol Pitt 
Published: June 2011

AbstractAttempts to create hierarchically structured, uniaxially oriented nanocomposites comprising cellulose nanowhiskers (CNWs), which promise anisotropic mechanical properties, are exceedingly rare. We report here the fabrication of uniaxially‐oriented arrays of microfibers based on poly(ethylene oxide) (PEO) and CNWs by electrospinning. Compared with the neat PEO fibers, the incorporation of CNWs within the fibers increased the storage modulus (E′) of arrays along the fiber axis of the PEO/CNW nanocomposite fibers. Successful incorporation of the CNWs within each of the as‐spun PEO/CNW nanocomposite fibers in the direction parallel to the fiber axis was verified by both scanning and transmission electron microscopy. magnified image
Helical Conformation in Crystalline Inclusion Complexes of V‐Amylose: A Historical Perspective
Authors: Putaux Jean‐Luc , Nishiyama Yoshiharu , Mazeau Karim , Morin Morgane , Cardoso Mateus B. , Chanzy Henri 
Published: June 2011

AbstractSummary: Amylose forms V‐type crystalline inclusion complexes with a large variety of small molecules. Several authors have proposed models for these complexes based on amylose single helices with 6, 7 and 8 glucosyl units per turn. However, so far, only a small number of crystal structures have been solved and several models are still hypothetical. We have recently shown that in the unit cell of such complex with isopropanol, the amylose molecules were organized in 7‐fold left‐handed helices, with isopropanol and water molecules located as guests both within and between the helices.
Phase Behavior of Poly(n‐butyl acrylate) and Poly(2‐ethylhexyl acrylate) in Nematic Liquid Crystal E7
Authors: Youcef Boumédiène Dali , Bouchaour Tewfik , Maschke Ulrich 
Published: June 2011

AbstractSummary: This paper reports on the phase behavior of photochemically crosslinked poly(n‐butyl acrylate) (PABu) and poly(2‐ethylhexyl acrylate) (PEHA) networks in a nematic liquid crystal (LC) solvent. The swelling properties of these networks were studied as a function of temperature using a low molecular weight LC (LMWLC), which is an eutectic mixture of cyanoparaphenylenes named E7. To obtain different polymer network densities, the ratio of the reactive monomers ABu (or EHA) to the crosslinking agent hexanedioldiacrylate (HDDA) was varied prior to polymerization/crosslinking reactions. Immersion of these networks in an excess of LC solvent allowed for the measurement of size increase by polarizing optical microscopy in terms of temperature. Diameter ratios were calculated considering swollen to dry network states of the samples. The uptake of LMWLC inside the network preferentially takes place around the nematic to isotropic transition temperature of the solvent. Phase diagrams in the concentration‐temperature framework were given and discussed as a function of crosslinking degree of the polymer network and temperature and phase behavior of the solvent.
Stimuli‐Responsive Polymers in Solution Investigated by NMR and Infrared Spectroscopy
Authors: Spěváček Jiří , Dybal Jiří 
Published: June 2011

AbstractSummary: Temperature‐induced and solvent composition‐induced phase separation in solutions of poly(N‐isopropylmethacrylamide) (PIPMAm) and other thermoresponsive polymers as studied by NMR and infrared (IR) spectroscopy is discussed. The fraction p of phase‐separated units (units with significantly reduced mobility) and subsequently, e.g., thermodynamic parameters characterizing the coil‐globule phase transition induced by temperature, were determined from reduced integrated intensities in high‐resolution 1H NMR spectra. This approach can be especially useful in investigations of phase separation in solutions of binary polymer systems. Information on behaviour of water during temperature‐induced phase transition was obtained from measurements of 1H NMR relaxation times of HDO molecules. NMR and IR spectroscopy were used to investigate PIPMAm solutions in water/ethanol (D2O/EtOH) mixtures where the phase separation can be induced by solvent composition (cononsolvency). Some differences in globular‐like structures induced by temperature and solvent composition were revealed by these methods.
Syndiotactic Polystyrene / Fullerene Composites: Elucidation of Structural Aspect
Authors: Chakraborty Chanchal , Malik Sudip , Guenet Jean‐Michel 
Published: June 2011

AbstractSummary: Syndiotactic polystyrene (sPS), an attractive polymer due to its wide range of application, forms polymer‐solvent intercalates with a large variety of solvent molecules ranging from liquids to solids. Recently, it has been realized that sPS intercalate prepared from SPS/naphthalene gel is more promising of making mesoporous materials. Here, the composite of sPS/fullerene have been prepared by taking advantage of sublimation of naphthalene. The different techniques as like XRD, SEM, HRTEM, FT‐IR, DSC, TGA etc have been employed to characterized sPS/fullerene composite. XRD investigation shows the presence of δ form sPS in the composite. SEM and HRTEM reveal the fibrillar network with fringe like structure in presence of fullerene only and the average diameter of fibril has increased as compared to pure sPS fibrils. The conductivities of these fibrils have been increased with increasing amount of fullerene.