bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cycloaddition Reactions of 7‐Benzylidenecycloocta‐1,3,5‐triene with Ethenetetracarbonitrile and 4‐Phenyl‐3H‐1,2,4‐triazole‐3,5(4H)‐dione
Authors: Clements Philip , Gream George E. , Kirkbride Paul K. , Pyke Simon M. 
Published: July 2005

AbstractAn (E)/(Z) mixture (3 : 2) of 7‐benzylidenecycloocta‐1,3,5‐triene (5) is obtained when 1‐benzylcycloocta‐1,3,5,7‐tetraene (7), prepared by an improved procedure, is treated with t‐BuOK in THF. Alternatively, a ca. 9 : 1 mixture (E)/(Z)‐5 can be prepared in a Wittig reaction involving benzaldehyde and cycloocta‐2,4,6‐trien‐1‐ylidenetriphenylphoshorane (9). Treatment of (E)/(Z)‐5 88 : 12 with ethenetetracarbonitrile (TCNE) gave a complex mixture of products, from which seven mono‐adducts and two bis‐adducts were isolated (Sect. 2.2.1). Of the mono‐adducts, four are π4+π2 adducts: two ((E)‐ and (Z)‐isomers) are derived from valence tautomers of the two isomers of (E)/(Z)‐5, while it is tentatively suggested that the other two (again (E)‐ and (Z)‐isomers) are formed from the intermediacy of a pentadienyl zwitterion (Sect. 2.3). The remaining three mono‐adducts, two of which are epimers, are π8+π2 adducts. It is suggested that they are derived from the intermediacy of homotropylium zwitterions (Sect. 2.3). For the two bis‐adducts, it is postulated that they are derived from an initial π2+π2 cycloaddition involving the homotropylium zwitterions followed by π4+π2 cycloaddition to the valence tautomer of each of the π2+π2 cycloadducts. With 4‐phenyl‐3H‐1,2,4‐triazole‐3,5(4H)‐dione (6), (E)/(Z)‐5 91 : 9 yielded two π4+π2 cycloadducts ((E)‐ and (Z)‐isomers) as well as two epimeric π8+π2 cycloadducts (Sect. 2.2.2). The intermediacy of pentadienyl (tentative suggestion) and homotropylium zwitterions accounts for the formation of the products (Sect. 2.3).
Culture of human umbilical vein endothelial cells on immobilized vascular endothelial growth factor
Authors: Ito Yoshihiro , Hasuda Hirokazu , Terai Hiroshi , Kitajima Takashi 
Published: July 2005

AbstractVascular endothelial growth factor (VEGF) was immobilized on substrata in photoreactive gelatin to control the adhesion and growth of vascular endothelial cells. The gelatin and VEGF were mixed in water and cast on a polystyrene dish or a silane‐coated glass plate. The surface was then photoirradiated in the presence or absence of a photomask and washed. Toughness of the immobilized material was confirmed by ethanol treatment. Human umbilical vein endothelial cells (HUVECs) grew on the immobilized VEGF but not on a nontreated surface. Growth of HUVEC increased significantly with an increase in the amount of immobilized VEGF, and the effects were inhibited by treatment with anti‐VEGF antibody. Thus, immobilized VEGF specifically interacted with HUVECs to permit growth in culture. Micropatterning of HUVEC cultures was also achieved using micropattern‐immobilized VEGF. This patterning technique may be useful for the formation of blood vessel networks in vitro. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Bone defect healing with an osteogenic protein‐1 device combined with carboxymethylcellulose
Authors: Cook Stephen D. , Salkeld Samantha L. , Patron Laura P. 
Published: July 2005

AbstractOne consideration for the practical use and application of osteogenic proteins is an effective method of delivery. This study evaluated a putty‐type collagen carrier with recombinant human osteogenic protein‐1 (rhOP‐1) ability to heal canine critical sized (2.5 cm) ulna segmental defects compared to rhOP‐1 with a particulate collagen carrier (OP device). The addition of carboxymethylcellulose (CMC) to the particulate collagen carrier (OPCMC device) to form the putty consistency was evaluated in two doses (3.5 and 1.75 mg rhOP‐1/g carrier). The CMC greatly improved the intraoperative handling and site containment of the device. For the one‐half dose and full‐dose sites there were no statistically significant differences in the radiographic grading of defect healing when treated with the particulate OP‐1 device and the device with CMC added. However, there was a dose effect with greater and earlier new bone formation observed with increased rhOP‐1. Mechanically, there were no differences between particulate and putty formulations, although again, a significant effect was observed for treatment dose with the full‐dose OPCMC device restoring 94% of the strength of the intact ulna compared to only 65% for the identical one‐half dose implant. Regardless of rhOP‐1 dose, the quality of union grading and total histologic score appearance were improved with the addition of CMC, although differences in histologic scoring were not statistically significant. Overall, the radiographic, mechanical, and histologic bone‐healing characteristics with the one‐half dose OPCMC device were similar to sites treated with the full‐dose OP device. The observed improvement in healing may allow for lesser amounts of the device or a device with less rhOP‐1 to be used. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Micromechanics of shelf‐aged and retrieved UHMWPE tibial inserts: Indentation testing, oxidative profiling, and thickness effects
Authors: Wernlé James D. , Gilbert Jeremy L. 
Published: July 2005

AbstractUnderstanding the surface micromechanical properties of ultra‐high‐molecular‐weight polyethylene (UHMWPE) may allow for improvement in its wear characteristics. Microtomed sections of two UHMWPE tibial bearings, one that had been irradiation sterilized and shelf‐aged, and the other irradiation sterilized and used in a patient, were subjected to depth sensing indentation testing. The microtomed sections exhibited a white band in the subsurface region that is characteristic of oxidation, and the indentation testing, followed by FTIR analysis at the same testing locations, was performed across this region and into the bulk of the material. Indentation testing yielded data leading to hardness, modulus, and energy dissipation factor (EDF). FTIR profiling generated information about oxidation; oxidation indices were calculated by taking a ratio of peak heights at 1716 cm−1 (ketone) to 2022 cm−1 (methylene). The mechanical properties showed a strong linear correlation with oxidation index above a minimum thickness. Modulus, hardness, and EDF all increased with increasing oxidation. The appropriate thickness‐to‐indentation‐depth ratio was determined by two methods and was found to be approximately 20:1. The mechanical properties through the oxidized region were seen to vary with depth into the sample in a profile similar to the oxidation profile. The differing aging environments of the tibial bearings are hypothesized to have had an effect on both the mechanical and oxidation profiles. The retrieved bearing exhibited a narrower oxidation profile with peaks closer to the surface, and oxidation indices of lower magnitude. The mechanical properties proved similar, with less intense and narrower readings for the retrieved sample. This research is consistent with much of the literature. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Fluoride coatings on orthodontic wire for controlled release of fluorine ion
Authors: Lee Su‐Hee , Kim Hae‐Won , Kong Young‐Min , Kim Hyoun‐Ee , Lee Sung‐Ho , Chang Young‐Il 
Published: July 2005

AbstractThe purpose of this study was to develop a new method of releasing fluorine in a controlled manner for applications in the field of orthodontic Ti‐based wire, namely the coating of fluorides on Ti. Thin films of two fluoride compounds, CaF2 and MgF2, were coated on Ti via the electron‐beam evaporation method. The fluorine was released rapidly from the as‐deposited MgF2 coating within a short period, and then the release rate slowed down. When the MgF2 coating was heat treated, this initial burst effect was decreased, but a significant amount of cracks were generated. On the other hand, in the case of the as‐deposited CaF2 coating, fluorine was released linearly for the entire period, without an initial burst. In the heat‐treated CaF2 coatings the trend was similarly observed. The linear fluorine release from the CaF2 coatings, even in the as‐deposited state, was attributed to the high degree of crystallinity of the coatings. A preliminary cell test showed favorable cell viability on both the fluoride coatings. Given their sustained and controlled fluorine release, these fluoride coatings, particularly CaF2, are suggested to be potentially useful in the field of orthodontic Ti‐based wire. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Apatite formed on/in agarose gel as a bone‐grafting material in the treatment of periodontal infrabony defect
Authors: Tabata Masashi , Shimoda Toru , Sugihara Kazumasa , Ogomi Daisuke , Ohgushi Hajime , Akashi Mitsuru 
Published: July 2005

AbstractThe present study was designed to evaluate the effects of a hydroxyapatite/agarose (HA/agarose) composite gel formed by a novel alternate soaking process for the treatment of periodontal infrabony defects in three dogs. After creating two‐wall infrabony periodontal defects on the medial aspect of the maxillary and mandibular second and forth premolars, the defects were implanted with temporary dental filling material (stopping) to induce inflammatory periodontal disease. Two months later, the mucoperiosteal flaps were raised, and after debridement, the infrabony defects were filled with one of the following three materials: (a) HA/agarose, (b) Bone ject (True‐Bone Ceramic‐collagen combined bone graft material, Koken, Japan), or (c) no material implantation (negative control). The animals were then randomly scheduled for sacrifice at 1, 2, and 6 months, and samples were taken for histological examination. In the HA/agarose gels, the 2‐month postoperative cavities exhibited regeneration to new attachments with the apposition of a new cementum and well‐oriented fibers. The neocementum was narrow and acellular, and the new bone apposition was limited. Six months postoperatively, newly formed bone was predominantly observed. The neocementum was wider and cellular. In the negative control, the 2‐month postoperative cavities exhibited no regeneration of the cementum, nor any formation of periodontal pockets. The six‐month postoperative cavities were nearly the same as the 2‐month cavities. The Bone ject, 2‐month postoperative cavities exhibited no regeneration of the periodontal tissue, nor any formation of periodontal pockets. Six months postoperatively, inflammatory granulation tissue was observed around the particles. The present study suggests that HA/agarose gels may play an important role in the regeneration of lost periodontal tissue. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Recovery of carboxylic acids C1C3 with organophosphine oxide solvating extractants
Authors: Wisniewski Maciej , Pierzchalska Magdalena 
Published: July 2005

AbstractThis study was aimed at examining the use of the organophosphine oxides Cyanex®921 and Cyanex®923 for the extraction of formic, acetic and propionic acids from aqueous solutions. The stripping of monocarboxylic acids with water from the loaded extractants was also examined. The studies were aimed at determining the equilibrium conditions for extraction and stripping. Overall, the effect of the kind of extractant was not significant although Cyanex®921 extracted carboxylic acids slightly better than Cyanex®923 with 1:1 complexes being formed by both extractants with the acids during extraction. The efficiency of extraction depended on temperature, acid concentration and solvent, with toluene a better diluent for the extractants than octane or Exxsol®D 220/230. Extraction efficiency increased as the concentration of acid in the feed decreased and, also, as the temperature increased, the amount of acid extracted decreased. The extraction and stripping isotherms were determined. The apparent enthalpy and entropy of the extraction reaction were determined. Distribution data for the transfer of carboxylic acids from aqueous (NaCl) solutions to organic solvents in the presence of trialkylphosphine oxide were determined at 293 K with the distribution ratios increasing as the concentration of NaCl increased. Copyright © 2005 Society of Chemical Industry
Optimisation of a serine protease coupling to Eudragit S‐100 by experimental design techniques
Authors: Silva Carla JSM , Gübitz Georg , Cavaco‐Paulo Artur 
Published: July 2005

AbstractA full factorial design was used to study the influence of four different variables, namely polymer concentration, carbodiimide concentration, time of reaction and blocking agent concentration, on the coupling of a serine protease into a soluble–insoluble polymer (Eudragit S‐100). All of the four factors studied have played a critical role in the protease coupling. Response surface methodology was used as an optimisation strategy to attain a conjugate with high activity yield and operational stability at 60 °C. Under optimised conditions (Eudragit, 2.5% w/v, carbodiimide, 0.2% w/v, coupling time, 1 h and blocking agent concentration, 0.05%), the conjugate activity yield was about 45% and its operational stability at 60 °C was increased by 1.7 times. After reusing the conjugate for five cycles, the remaining activity was still 72% of the initial value when compared with the native enzyme. Several tests confirmed that the enzyme was covalently crosslinked to Eudragit, which represents an improvement in the carbodiimide coupling of proteases into soluble–insoluble polymers. Copyright © 2005 Society of Chemical Industry
Chronic BDNF deficiency permanently modifies excitatory synapses in the piriform cortex
Authors: Nanobashvili Avtandil , Jakubs Katherine , Kokaia Merab 
Published: July 2005

AbstractBrain‐derived neurotrophic factor (BDNF), aside from its classic neurotrophic role in development and survival of neurons, has been shown to be involved in modification and plasticity of central synapses. In mice with BDNF gene deletion (BDNF+/−), deficits in synaptic transmission are often observed but are reversed readily by administration of BDNF, suggesting its acute effect. In support, blockade of BDNF signaling in wild‐type hippocampal slices by TrkB‐IgG closely reproduces synaptic alterations observed in BDNF+/− mice. We demonstrate that in BDNF+/− mice, lateral olfactory tract (LOT) synapses exhibit decreased release probability of glutamate, suggested by increased paired‐pulse facilitation (PPF) of field excitatory postsynaptic potentials (fEPSPs), as well as by slower blocking rate of N‐methyl‐D‐aspartate (NMDA) receptor‐mediated excitatory postsynaptic currents (EPSCs) by MK‐801 in the pyramidal neurons of the piriform cortex. The changes in PPF were not mimicked in wild‐type mice by acute blockade of BDNF signaling by TkrB‐IgG. These data imply that BDNF deficit during development might lead to chronic changes of excitatory transmission in LOT synapses. Modification of the LOT synapses in BDNF+/− mice was associated with altered inhibitory drive onto the mitral cells from the granule and glomerular neurons, which in turn exhibited decreased renewal rate compared to that in wild‐type mice. Taken together, these data suggest that BDNF deficiency can have both acute and more permanent effects on synaptic function, particularly when BDNF signaling is compromised during the early stages of brain development. In the latter case, altered synaptic properties in BDNF+/− mice could be secondary to other complex changes in the brain, e.g., cell survival/proliferation. © 2005 Wiley‐Liss, Inc.
Role of Mayven, a kelch‐related protein in oligodendrocyte process formation
Authors: Williams Sarah K. , Spence Heather J. , Rodgers Ryan R. , Ozanne Bradford W. , FitzGerald Una , Barnett Susan C. 
Published: July 2005

AbstractOligodendrocyte function is central to the maintenance of the normal nervous system in health and disease. In particular, process formation and the generation of large sheets of myelin are important components of their biological properties. We have investigated the role of Mayven, a recently identified member of the kelch family of proteins, in process extension in oligodendrocyte‐lineage cells. The kelch superfamily consists of a large number of structurally diverse proteins characterized by the presence of a kelch‐repeat domain. Other members of this family associate with the actin cytoskeleton and regulate process length. Mayven is expressed predominantly in the CNS, has six kelch repeats, and is an actin‐binding protein, associating with actin through its kelch‐repeat domain. We have cloned rat Mayven and examined its role in the oligodendrocyte lineage by using RT‐PCR, RNA interference, and a truncated, dominant‐negative myc‐tagged Mayven. Oligodendrocyte precursors treated with siRNA directed to Mayven have reduced process length, but there was no change in migration or expression of differentiation markers. Immunocytochemistry demonstrated that Mayven associated with F‐actin at cell tips. Finally, overexpression of truncated Mayven lacking the SH3 ligand binding domain in oligodendrocyte‐lineage cells resulted in shorter process formation, which was augmented when the cells were plated on laminin and fibronectin. These data suggest a role for Mayven in oligodendrocyte precursor cell process formation. © 2005 Wiley‐Liss, Inc.
Functional mechanisms of apoptosis‐related proteins in neonatal rat cerebellum are differentially influenced by ethanol at postnatal days 4 and 7
Authors: Siler‐Marsiglio Kendra I. , Paiva Michael , Madorsky Irina , Pan Qun , Shaw Gerry , Heaton Marieta B. 
Published: July 2005

AbstractExposure of the developing nervous system to ethanol (EtOH) produces neurological aberrations associated with fetal alcohol syndrome. During a well‐defined period, cerebellar neurons are highly susceptible to EtOH‐induced death, primarily through apoptosis. Neonatal rodent cerebellum is exquisitely sensitive to EtOH on postnatal days 4–6 (P4–6); however, at slightly later developmental ages (P7 and later), EtOH effects are minimal. We have previously shown that EtOH differentially influences expression of apoptosis‐related proteins of the Bcl‐2 survival‐regulatory gene family in P4 and P7 cerebellum. In the present study, the effects of EtOH on multiple functional mechanisms of Bcl‐2, Bcl‐xL, and Bax were investigated to characterize further the processes underlying these disparate EtOH sensitivities. For these analyses, we addressed the following questions, by using P4 and P7 cerebellar tissue following in vivo exposure: 1) Are there differential patterns of expression of antiapoptotic Bcl‐2 or proapoptotic Bax in EtOH‐vulnerable Purkinje cells that could contribute to the different degrees of temporal EtOH vulnerability? 2) How does EtOH affect intracellular localization of apoptosis‐related proteins? 3) Does cleavage of Bax contribute to EtOH sensitivity? 4) Does EtOH differentially modulate cerebellar protein–protein interactions of Bcl‐2, Bcl‐xL, and Bax at the vulnerable vs. the resistant ages? Overall, we show that, at P4, the EtOH‐mediated effects on Bcl‐2, Bcl‐xL, and Bax favor a prodeath response, whereas most of the intracellular responses to EtOH exposure at P7 promote survival. Such differential responsiveness likely plays a major role in the disparate ethanol vulnerability at these two postnatal ages. © 2005 Wiley‐Liss, Inc.
Amorphous Polyethylene by Tandem Action of Cobalt and Titanium Single‐Site Catalysts
Authors: Bianchini Claudio , Frediani Marco , Giambastiani Giuliano , Kaminsky Walter , Meli Andrea , Passaglia Elisa 
Published: July 2005

AbstractSummary: A variety of branched polyethylenes, spanning from semicrystalline LLDPE to completely amorphous, rubbery PE, was obtained from ethylene by homogeneous tandem catalysis using combinations of CoCl2(N) (1) (N = [1‐(6‐benzo[b]thiophen‐2‐yl‐pyridin‐2‐yl)‐ethylidlene)‐(2,6‐diisopropyl‐phenyl)‐amine) and [(η5‐C5Me4)SiMe2(tBuN)]TiCl2 (2) in the presence of MAO at 30 °C. The productivity reached a maximum of 4 570 kg PE (mol Ti · h)−1 at χCo = 0.50, yielding a rubbery material with d25 = 0.868 g · cm−3 and Tg = −55 °C.Conversion of ethylene into branched polyethylene using CoII iminopyridyl complex CoCl2(N) (1) and TiCl2[(η5‐C5Me4)SiMe2(tBuN)] (2).magnified imageConversion of ethylene into branched polyethylene using CoII iminopyridyl complex CoCl2(N) (1) and TiCl2[(η5‐C5Me4)SiMe2(tBuN)] (2).
Wettability of Polyhedral Oligomeric Silsesquioxane Nanostructured Polymer Surfaces
Authors: Turri Stefano , Levi Marinella 
Published: July 2005

AbstractSummary: Some model structures of waterborne polyurethane anionomers containing various amounts (ca. 3–20%) of a diol functionalized polyhedral oligomeric silsesquioxane (POSS) nanofiller were prepared. X‐ray diffraction showed the formation of a nanocrystalline structure in all copolymers considered. Static contact angle measurements indicated a significant enhancement of surface hydrophobicity as well as reduction in surface tension components even at the least POSS level (3%). Dynamic contact angle cycles allowed the evaluation of the hysteresis, which was found to be large and kinetically increasing in POSS‐modified samples. Film topography was analyzed by AFM, showing a more pronounced roughness in the nanostructured surface.The AFM image showing a moderate roughness increase.magnified imageThe AFM image showing a moderate roughness increase.
Specific aspartate residues in FET3 control high‐affinity iron transport in Saccharomyces cerevisiae
Authors: Bonaccorsi di Patti Maria Carmela , Felice Maria Rosa , De Domenico Ivana , Lania Amalia , Alaleona Flaminia , Musci Giovanni 
Published: July 2005

AbstractSite‐directed mutagenesis was performed on a set of six aspartate residues of Fet3, the multicopper ferroxidase involved in high‐affinity iron transport in Saccharomyces cerevisiae, in order to comprehend the molecular determinants of the protein function. Asp312, Asp315, Asp319 and Asp320 were predicted by homology modelling to be located in a negatively charged surface‐exposed loop of the protein. Other two aspartate residues (Asp278 and Asp279) are placed close to the type 1 copper‐ and iron‐binding sites, possibly linking these sites to the negatively charged region. In vivo results showed that mutation of Asp319 and Asp320 to yield D319N and D320N derivatives strongly impairs the ability of the yeast to grow under iron‐limiting conditions. In particular, substitution of Asp320 with asparagine essentially abolished the Fet3‐dependent iron transport activity. All other mutants (D278Q, D279N, D312N and D315I) behaved essentially as the wild‐type protein. The electron paramagnetic resonance spectrum of the soluble forms of D319N and D320N showed significant changes of the copper sites' geometry in D319N but not in D320N. At variance with the membrane‐bound forms, soluble D319N and D320N derivatives were highly susceptible to proteolytic degradation, suggesting that replacement of Asp319 or Asp320 locally modifies the structure of Fet3, making the protein sensitive to proteolysis when it is not protected by the membrane environment. In turn, this might be evidence of a shielding role of the permease Ftr1, which could interact with Fet3 at the level of the aspartate‐rich negatively charged region. Copyright © 2005 John Wiley & Sons, Ltd.