bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermoreversible hydrogel scaffolds for articular cartilage engineering
Authors: Fisher John P. , Jo Seongbong , Mikos Antonios G. , Reddi A. Hari 
Published: September 2004

AbstractArticular cartilage has limited potential for repair. Current clinical treatments for articular cartilage damage often result in fibrocartilage and are associated with joint pain and stiffness. To address these concerns, researchers have turned to the engineering of cartilage grafts. Tissue engineering, an emerging field for the functional restoration of articular cartilage and other tissues, is based on the utilization of morphogens, scaffolds, and responding progenitor/stem cells. Because articular cartilage is a water‐laden tissue and contains within its matrix hydrophilic proteoglycans, an engineered cartilage graft may be based on synthetic hydrogels to mimic these properties. To this end, we have developed a polymer system based on the hydrophilic copolymer poly(propylene fumarate‐co‐ethylene glycol) [P(PF‐co‐EG)]. Solutions of this polymer are liquid below 25°C and gel above 35°C, allowing an aqueous solution containing cells at room temperature to form a hydrogel with encapsulated cells at physiological body temperature. The objective of this work was to determine the effects of the hydrogel components on the phenotype of encapsulated chondrocytes. Bovine articular chondrocytes were used as an experimental model. Results demonstrated that the components required for hydrogel fabrication did not significantly reduce the proteoglycan synthesis of chondrocytes, a phenotypic marker of chondrocyte function. In addition, chondrocyte viability, proteoglycan synthesis, and type II collagen synthesis within P(PF‐co‐EG) hydrogels were investigated. The addition of bone morphogenetic protein‐7 increased chondrocyte proliferation with the P(PF‐co‐EG) hydrogels, but did not increase proteoglycan synthesis by the chondrocytes. These results indicate that the temperature‐responsive P(PF‐co‐EG) hydrogels are suitable for chondrocyte delivery for articular cartilage repair. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 268–274, 2004
Theoretical study on reaction mechanism of the fluoromethylene radical with nitrogen dioxide
Authors: Zhang Jia‐Xu , Liu Jing‐Yao , Li Ze‐Sheng , Sun Chia‐Chung 
Published: September 2004

AbstractThe complex doublet potential energy surface for the reaction of 1CHF with NO2, including 14 minimum isomers and 30 transition states, is explored theoretically at the B3LYP/6‐311G(d,p) and CCSD(T)/6‐311G(d,p) (single‐point) levels of theory. The initial association between 1CHF and NO2 is found to be the carbon‐to‐middle‐nitrogen attack forming an energy‐rich adduct a (HFCNO2) with no barrier, followed by concerted O‐shift and CN bond rupture leading to product P2 (NO + HFCO), which is the most abundant. In addition, a can take a 1,3‐H‐shift to isomer b (FCN(O)OH) followed by the dissociation to form the second feasible product P4 (OH + FCNO). The least favorable pathway is that b undergoes a concerted OH‐shift to form d (HO(F)CNO), which will dissociate to product P5 (HF+OCNO) via side HF‐elimination. The secondary dissociation of P5 may form product P7 (HF+NO+CO) easily. Furthermore, the 1CHF attack at the end‐O of NO2 is a barrier‐consumed process, and thus may only be of significance at high temperatures. The comparison with the analogous reactions 1CHCl + NO2 is discussed. The present study may be helpful for probing the mechanism of the title reaction and understanding the halogenated carbine chemistry. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1888–1894, 2004
Noah Porter's problem and the origins of American psychology
Authors: Richards Graham 
Published: September 2004

AbstractThe twin problems facing nineteenth‐century American “mental and moral philosophy” of the nature of psychological language and the constraints that religious beliefs placed on possibilities of innovation in a “scientific Psychology” are both highly visible in the work of Noah Porter, who was unable to resolve them. They are also more covertly identifiable in the works of James McCosh and others in this school. It is suggested that the transition to the “New Psychology” of the 1880s and 1890s needs to be rethought in light of this in three respects: (a) ironically, it entailed repressing insights into the psychological language problem, (b) the legacy of the religious factor profoundly affected U.S. Psychology and played a less unambiguously negative role in its fortunes than customarily portrayed, and (c) the transition was itself a more complex and protracted process than is portrayed in traditional “revolutionary” accounts. © 2004 Wiley Periodicals, Inc.
Riding natural scientists' coattails onto the endless frontier: The SSRC and the quest for scientific legitimacy
Authors: Solovey Mark 
Published: September 2004

AbstractThis article proposes that the postwar National Science Foundation (NSF) debate constituted a critical, transitional episode in American social science and partisan politics. I show that by responding to powerful conservative critics in the scientific and political communities, the Social Science Research Council's (SSRC's) leading scholars (re)asserted a contested scientistic strategy—to advance the social sciences by following the natural sciences. Further, I reconstruct a wider and longer framework of analysis in order to recover central challenges to the scientistic strategy raised by prominent liberal scholars who rejected the associated commitments to value neutrality and disinterested professionalism. In developing this framework for understanding the contrasting fortunes of each strategy, this article argues that the NSF debate has a deep historical significance—for the social sciences, for American liberalism, and for the nation. © 2004 Wiley Periodicals, Inc.
Stereocontrolled synthesis of (7E,9Z)‐[9,10‐2H]‐conjugated linoleic acid
Authors: Broustal Garance , Loreau Olivier 
Published: September 2004

AbstractTo study the metabolism of minor conjugated linoleic acid isomers (CLAs), (7E,9Z)‐[9,10‐2H] CLA was prepared in three steps from a conjugated enyne precursor. In the labelling step, deuterium atoms were introduced by partial reduction of the triple bond using deuterated disiamylborane and acetic acid‐d4. Deuterated (7E,9Z) CLA was obtained with high isotopic enrichment (>99%) and purity greater than 95%. Copyright © 2004 John Wiley & Sons, Ltd.
Microwave‐enhanced, solvent‐free synthesis of singly and doubly 13C‐labelled trans‐cinnamic acid at the α‐ and β‐carbon positions
Authors: Ma Guibin , Hayes Sophia E. 
Published: September 2004

Abstract13C‐labelled trans‐cinnamic acid (3‐phenyl‐2‐propenoic acid) has been synthesized in one step using benzaldehyde‐carbonyl‐13C and malonic acid‐2‐13C in the presence of ammonium acetate under microwave irradiation and solvent‐free conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Direct transdifferentiation gives rise to the earliest new hair cells in regenerating avian auditory epithelium
Authors: Roberson David W. , Alosi Julie A. , Cotanche Douglas A. 
Published: September 2004

AbstractThe avian auditory epithelium is capable of complete regeneration after hair cell (HC) loss. Most new HCs arise via cell division, but approximately one‐third of new HCs arise via direct transdifferentiation (DT), in which supporting cells (SCs) alter their phenotype without dividing. In this study, we used synchronous, gentamicin‐induced near‐total HC loss in the basal end of the epithelium and continuous infusion of the cell division marker bromodeoxyuridine (BrdU) to identify the origin of each individual regenerating HC. Early new HCs were identified by immunolabeling for the HC‐specific marker myosin‐VIIa, and mitotic cells with BrdU immunolabeling. The first new HCs arising via DT appear 72–96 hr after gentamicin, 24–48 hr earlier than the first new mitotic HCs. After Day 6, however, most new HCs are mitotic. The “intermediate” morphology that has been suggested to be characteristic of DT is seen in HCs arising via both pathways. These findings suggest that DT is a simpler, more rapid process that produces the first new HCs, and that mitotic regeneration is somewhat slower but ultimately produces most new HCs. The identical morphology of regenerating HCs from both pathways suggests that once HC fate is established, all new HCs follow similar cellular processes during differentiation and reorganization into the regenerated epithelium. © 2004 Wiley‐Liss, Inc.
Finding yourself: How social identity affects leadership
Authors: Ruderman Marian N. , Ernst Christopher 
Published: September 2004

AbstractIn today's increasingly volatile and complex organizational environment, it's as important as ever for leaders to understand themselves. But it's no longer enough for them to be aware of their capabilities, motivations, styles, and values. Leaders now must also gain knowledge of their social identities—their membership in certain social groups defined by categories such as gender, race, and religion and the implications of belonging to these groups.
Investigation of the Interpolymer Complex between Hydroxypropyl Cellulose and Maleic Acid‐Styrene Copolymer, 1
Authors: Bumbu Gina‐Gabriela , Vasile Cornelia , Eckelt John , Wolf Bernhard A. 
Published: September 2004

AbstractSummary: The hydrogen bonding‐interpolymer association of hydroxypropyl cellulose (HPC) with maleic acid‐styrene (MAc‐S) copolymer has been investigated in dilute aqueous solution by viscometry, turbidimetry and potentiometry. At a mixing ratio between MAc‐S and HPC of 10:90, the solution exhibits a phase separation upon heating, while for other mixing ratio no phase separation could be detected. The stability of the interpolymer complex (IPC) increases as the temperature rises. The stoichiometry of the IPC, in mole units, was estimated as being MAc‐S:HPC = 5:2. The thermodynamic functions (enthalpy and entropy) of the complexation process have been determined.Dependence of IPC concentration in H2O/MAc‐S/HPC system on the mole fraction of MAc‐S in polymer mixture at different temperatures.magnified imageDependence of IPC concentration in H2O/MAc‐S/HPC system on the mole fraction of MAc‐S in polymer mixture at different temperatures.
Cover Picture: Macromol. Chem. Phys. 14/2004
Authors: Yoo Youngjae , Choi Kil‐Yeong , Lee Jae Heung 
Published: September 2004

Cover: The picture on the cover shows a schematic representation of the procedure for formation of polycarbonate/MMT nanocomposites via microwave‐aided solid state polymerization.Further details can be found in the Full Paper by Y. Yoo, K.‐Y. Choi, and J. H. Lee* on page 1863.
A Physical Method of Fabricating Hollow Polymer Spheres Directly from Oil/Water Emulsions of Solutions of Polymers
Authors: Kim Young Baek , Yoon Kyung‐Sup 
Published: September 2004

AbstractSummary: A new physical method of fabricating hollow spheres from different polymers has been developed. In this method, emulsions were prepared by mixing organic solutions of polystyrene, poly(D,L‐lactide‐co‐glycolide) (PLGA), and bacterial poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), water, and surfactants. The evaporation of solvents at room temperature caused a phase separation that eventually yielded hollow spheres. Molecular weights, concentrations of polymers, and the natures of surfactant and solvent were important aspects of hollow sphere formation and structure. A mechanism for the formation of hollow spheres is proposed based on observations made using an optical microscope equipped with a digital camcorder and using scanning electron microscopy images of hollow spheres obtained under different conditions.A scanning electron microscopy image of a broken smaller hollow sphere prepared using a 7 wt.‐% polystyrene solution (diameter of the sphere ∼10 micrometers).magnified imageA scanning electron microscopy image of a broken smaller hollow sphere prepared using a 7 wt.‐% polystyrene solution (diameter of the sphere ∼10 micrometers).
Mapping Acid‐Catalyzed Deprotection in Thin Polymer Films: Fluorescence Imaging Using Prefluorescent 7‐Hydroxycoumarin Probes
Authors: Frenette Mathieu , Coenjarts Chris , Scaiano J. C. 
Published: September 2004

AbstractSummary: Fluorescent images that illustrate acid‐catalyzed tert‐butoxycarbonyl (tBoc) deprotection patterns in polymer films were obtained using fluorescent sensors based on 7‐hydroxycoumarin dyes. Three commercial 7‐hydroxycoumarins, which are highly fluorescent, become practically nonemissive upon protection of the 7‐hydroxyl position with tBoc. In thin polymer films, the protected “prefluorescent” probes can return to their deprotected, fluorescent states by reaction with catalytic amounts of photogenerated acid and mild heating.Protected probes become highly fluorescent after acid‐induced deprotection.magnified imageProtected probes become highly fluorescent after acid‐induced deprotection.
1H and 13C assignments of two new triterpenes from Cladocolea grahami
Authors: Rios María Yolanda , Aguilar‐Guadarrama A. Berenice 
Published: September 2004

AbstractThe structure elucidation and 1H and 13C assignments of the new triterpenes 3β‐palmitoxy‐7β‐hydroxyolean‐12‐ene (1) and its hydrolysis product 3β,7β‐dihydroxyolean‐12‐ene (2) and 3β‐sn‐glyceroyl‐(1″‐palmitoxy)urs‐12‐ene (3), isolated from the aerial parts of Cladocolea grahami (Loranthaceae), are reported. Copyright © 2004 John Wiley & Sons, Ltd.
A 3D finite element simulation model for TBM tunnelling in soft ground
Authors: Kasper Thomas , Meschke Günther 
Published: September 2004

AbstractA three‐dimensional finite element simulation model for shield‐driven tunnel excavation is presented. The model takes into account all relevant components of the construction process (the soil and the ground water, the tunnel boring machine with frictional contact to the soil, the hydraulic jacks, the tunnel lining and the tail void grouting). The paper gives a detailed description of the model components and the stepwise procedure to simulate the construction process. The soil and the grout material are modelled as saturated porous media using a two‐field finite element formulation. This allows to take into account the groundwater, the grouting pressure and the fluid interaction between the soil and slurry at the cutting face and between the soil and grout around the tail void. A Cam‐Clay plasticity model is used to describe the material behaviour of cohesive soils. The cementitious grouting material in the tail void is modelled as an ageing elastic material with time‐dependent stiffness and permeability. To allow for an automated computation of arbitrarily long and also curvilinear driving paths with suitable finite element meshes, the simulation procedure has been fully automated. The simulation of a tunnel advance in soft cohesive soil below the ground water table is presented and the results are compared with measurements taken from the literature. Copyright © 2004 John Wiley & Sons, Ltd.
Modification of polystyrene properties through grafting with N‐vinylcarboxamido‐2‐methylpropane sulfonic acid monomer
Authors: Aggour Y A 
Published: September 2004

AbstractPolystyrene (PS) possesses good mechanical properties, but its surface is relatively inert and hydrophobic. Grafting of N‐vinylcarboxamido‐2‐methylpropane sulfonic acid (VCMP) is useful to hydrophilize the PS surface. Grafting was performed using benzoyl peroxide (BPO) as an initiator in toluene:methanol solvent mixture (3:1 volume ratio). The influence of the main factors on grafting, such as temperature, time, concentrations of initiator, PS and VCMP, has been studied. The results show that the initial rate of polymerization and percentage of grafting are enhanced by increased temperature. Furthermore, the specific rate constants of the first order reaction/are determined, and the activation energy of the grafting reaction is estimated. The grafting parameters are established and a suitable mechanism of the reaction is proposed. The grafted PS is to characterized through infrared spectra, intrinsic viscosity, thermogravimetric analysis (TGA) and differential gravimetric analysis (DTG). The kinetics of thermal degradation and the order of the thermal stabilities are given. Also the decomposition activation energies of the thermal degradation are determined, and confirm the thermal stabilities of the polymers used.© 2004 Society of Chemical Industry
Solvatochromism of dyes. Part IV—Energetic characteristics of merocyanine derivatives of 1‐phenyl‐2‐[2‐(3‐X‐4‐hydroxy‐5‐R‐phenyl)ethenyl]‐3,3‐dimethyl‐3H‐indolium cation
Authors: Wróblewska Elwira K. , Soroka Jacek A. , Soroka Krystyna B. , Ga̧siorowska Monika 
Published: September 2004

AbstractThe fundamental energetic parameters (intercepts and slopes of straight lines approximating energetic levels) of solvatochromic betaines generated by deprotonation of 2‐(4‐hydroxystyryl)‐3H‐indolium salts were determined from solvatochromic data in one‐component solvents. It was demonstrated that the solvatochromism of the investigated dyes can be described by the VBHB (vinylogous amide–betaine–hydrogen‐bonded betaine) physical model. In comparison with similar dyes, the ability to form hydrogen‐bonded solvates is weaker owing to the higher acidity of the dye precursor used. The type of observed solvatochromism was determined. Copyright © 2004 John Wiley & Sons, Ltd.
Angiopoietin 2 expression is related to histological grade, vascular density, metastases, and outcome in prostate cancer
Authors: J:son Lind Anna , Wikström Pernilla , Granfors Torvald , Egevad Lars , Stattin Pär , Bergh Anders 
Published: September 2004

AbstractBACKGROUNDIn several malignant tissues, the angiopoietins are principal regulators of vascular growth and regression, but in normal prostate and prostate tumors the role of the angiopoietins is unknown.METHODSAngiopoietin (ang) 1 and 2 were immunolocalized in TUR‐diagnosed prostate tumors with long follow‐up and the expression was related to vascular density and clinopathological variables.RESULTSAng 1 was strongly expressed in the basal epithelial cell layer in non‐malignant tissue, whereas tumors had lower levels localized to the epithelial cells. A weak ang 2 immu‐noreaction was observed in non‐malignant tissue and in low to intermediate Gleason score (GS) tumors, with a similar expression pattern. However, most high GS tumors showed an intense ang 2 staining. Ang 2 was significantly correlated to GS, density of endoglin stained blood vessels, metastases, and to cancer specific survival.CONCLUSIONSWe conclude that ang 2 probably is an important regulator of angiogenesis in prostate cancer. © 2004 Wiley‐Liss, Inc.
11th International Conference on Phonon Scattering in Condensed Matter (Phonons 2004), St. Petersburg, Russia, 25–30 July 2004
Authors: Kent A. J. 
Published: September 2004

AbstractConference Reports are meant to offer an authoritative view on a recently held scientific meeting rather than a comprehensive list of the conference presentations. Authors are invited to describe what they feel were the most interesting contributions.The full Proceedings of the 11th International Conference on Phonon Scattering in Condensed Matter (Phonons 2004) will be published in phys. stat. sol. (c) in early 2005.
Training ACD/LogP with Experimental Data
Authors: Walker Matthew J. 
Published: September 2004

AbstractThe commercial physical property calculation software, ACD/Labs Physico‐Chemical Laboratory, has the capability to accept experimental data for logP and pKa values which it can use to “train” its model to better predict un‐represented structural classes. An attempt was made to produce a training set, called a “user database” by the software, based on Merck in‐house data, which could be used to train the ACD/LogP model in order to achieve better predictivity on molecules of interest to Merck researchers. A user database consisting of a randomly selected 10% subset of the available Shake‐Flask measured logP data was constructed and used to predict itself as well as the remaining 90% data set. The training produced a modest increase in accuracy of the model, with the R2 value of the prediction improving in the test set from 0.316 to 0.527. Narrowing the selection to a project‐based, targeted subset of the in‐house data in hopes of decreasing the diversity of the set, enhanced the coverage of the model but only produced an improvement in the R2 value from 0.350 to 0.537. Finally, training on a single, small representative of a structural class produced a sizable reduction in the bias of the prediction in a congeneric series of compounds, essentially confirming the original claim of the software developers. These improvements came with an increase in time and machine load to perform the calculation relative to the size of the training set.
Feeding fish with diets of different ratios of C3‐ and C4‐plant‐derived ingredients: a laboratory analysis with implications for the back‐calculation of diet from stable isotope data
Authors: Focken Ulfert 
Published: September 2004

AbstractBack‐calculation of the diet is one of the most frequent applications of stable isotope techniques in animal ecology. These calculations are often based on two assumptions: a constant trophic shift for all dietary items and a linear response of the isotopic ratios to different mixtures of two isotopically distinct feeds. In a laboratory experiment, fish (Nile tilapia, Oreochromis niloticus) were fed semi‐synthetic diets prepared either from wheat or corn ingredients, or from three blended diets (25, 50, 75% wheat components). Isotopic analysis of the lipid‐free and lipid fraction of the fish after the experiment revealed that the trophic shift was not constant for wheat‐ and corn‐based diets. The isotopic response to the mixed diets was not linear, leading to a statistically significant over‐estimation of the corn component in the back‐calculation. Both effects are in agreement with published data on the isotopic effects of C3‐ and C4‐plant materials in the diet. Copyright © 2004 John Wiley & Sons, Ltd.