bluuebunny/crossref_metadata_2025_split huggingface dataset:
High hydrostatic pressure extraction of flavonoids from propolis
Authors: Shouqin Zhang , Jun Xi , Changzheng Wang 
Published: September 2004

AbstractA high hydrostatic pressure extraction (HHPE) method is presented for the extraction of flavonoids from propolis. Various experimental conditions of the HHPE process, such as solvents, ethanol concentration (35–95%, v/v), HHPE pressure (100–600 MPa), HHPE time (1–10 min) and solid/liquid ratio (1:5–1:45 g cm−3), were investigated to optimize the extraction process. The extraction yield with HHPE for 1 min was higher than those using extraction at room temperature for 7 days and heat reflux extraction for 4 h respectively. From the viewpoints of extraction time, the extraction efficiency and the extraction yield of flavonoids, HHPE was more effective than the conventional extraction methods studied. Copyright © 2004 Society of Chemical Industry
Why are we still arguing about globalization?
Authors: Sumner Andrew 
Published: September 2004

AbstractThis paper addresses the following question: why are we still arguing about globalization? Focus is placed on the conceptual point of departure, ‘globalization’ and its quantification. Differentiation is made between two perspectives on global economic integration: globalization as liberalization versus globalization as internationalism. The former, a policy input, a process of ‘opening’, leading to the latter. The latter, a policy outcome or the end outcome of ‘openness’, possible with or without the former. Selected literature on globalization and growth is discussed using the above criteria, categorizing ‘proponents’ and ‘sceptics’. The question is posed: to what extent differing approaches to conceptualizing globalization are responsible for generating different research findings. Copyright © 2004 John Wiley & Sons, Ltd.
HIV/AIDs and development concern us all
Authors: Barnett Tony 
Published: September 2004

AbstractDevelopment studies have increasingly lost sight of engagement with long term issues as short term, often consultancy funding, has been available for ever shorter and more ‘practical’ projects. This has meant that one of the most important developmental events—the HIV/AIDs epidemic—has been largely neglected by the development studies community. This article outlines the major developmental implications of the epidemic together with basic information about the disease and the epidemic. Copyright © 2004 John Wiley & Sons, Ltd.
NGDOs' role in building poor people's capacity to benefit from globalization
Authors: Tembo Fletcher 
Published: September 2004

AbstractThere has been a growing recognition of the role of Non‐Governmental Development Organizations (NGDOs) in strengthening civil society as an effective strategy for poverty eradication. This approach includes broad‐based development ownership and empowerment of the poor. The paper argues that in the context of globalization NGDOs need to focus on expanding space for poor people to engage with emerging forms of states and markets for their livelihood advantage. This implies creating space where the poor can effectively negotiate the global discourses and frameworks of development from their particular experiences and images of reality. In this position, the poor will find room for manoeuvre within which to influence the local, national and global processes and structures for their benefit. Copyright © 2004 John Wiley & Sons, Ltd.
Economic development in a changing globalized economy
Authors: Huq Mozammel , Tribe Michael 
Published: September 2004

AbstractThis introductory article provides an overview of the Development Studies Association's 2003 annual conference, the theme of which was Globalization and Development. A brief summary of the articles that have been based on three plenary addresses follows the overview, together with outlines of the contents of the seven other articles included in this special issue of the Journal of International Development. Opposing views about the role of globalization in international development, particularly as it relates to developing countries, are then summarized within in a broad historical context. Some of the published evidence concerning the economic impact of globalization is then presented, continuing the adversarial standpoints of opposing ‘camps’. The introduction is concluded with some discussion about future prospects for a ‘globalized’ world. Copyright © 2004 John Wiley & Sons, Ltd.
Quaternary ecological and geomorphic changes associated with rainfall events in presently semi‐arid northeastern Brazil
Authors: Auler Augusto S. , Wang Xianfeng , Edwards R. Lawrence , Cheng Hai , Cristalli Patrícia S. , Smart Peter L. , Richards David A. 
Published: September 2004

AbstractSeveral geomorphic features and palaeobiotic remains in now semi‐arid northeastern Brazil indicate major palaeoenvironmental changes during past periods of increased rainfall. 230Th mass spectrometric ages of speleothems and travertines have allowed the determination of the timing and duration of wetter than present conditions. The data demonstrate that wet events have occurred throughout much of the Pleistocene, present dry conditions having been established at the end of the Younger Dryas. A markedly different fauna comprising megafaunal elements not adapted to the present low arboreal scrubland caatinga vegetation existed in the area. Palaeobotanical remains embedded in travertine indicate forested vegetation at these wetter intervals, suggesting that the caatinga was then replaced or mixed with a semi‐deciduous forest. Due to the abundance of travertine sites containing fossil botanical remains in northeastern Brazil, it is believed that forest expansion occurred over large areas of the now semi‐arid zone, showing that the long hypothesised forested links between biodiversity‐rich Amazon and Atlantic rainforests may indeed have existed during these moister phases. Copyright © 2004 John Wiley & Sons, Ltd.
Colombian vegetation at the Last Glacial Maximum: a comparison of model‐ and pollen‐based biome reconstructions
Authors: Marchant Robert , Boom Arnoud , Behling Hermann , Hooghiemstra Henry , Melief Bert , Geel Bas Van , Hammen Thomas Van der , Wille Michael 
Published: September 2004

AbstractColombian vegetation, at the ecological level of the biome, is reconstructed at the Last Glacial Maximum (LGM) using two methods. A reconstruction of modern biomes shows that, for the majority of the sites, the pollen data accurately reflect the potential vegetation, even though much of the original vegetation has been transformed by agricultural practices. At 18 000 14C yr BP a generally cool and dry environment is reflected in biome assignments of cold mixed forests, cool evergreen forests and cool grassland/shrub, the latter extending to lower altitudes than presently recorded. Differential responses of the vegetation to climatic shifts are related to changes in moisture sources and the importance of edaphic control on the vegetation. Secondly, biomes at the LGM are also investigated by applying a vegetation model (BIOME‐3) set to operate at CO2 levels of 200 ppmV and with climatic data from 12 meteorological stations that encompass a range of environments within Colombia. At lower altitudes it is apparent that moisture is the dominant control on driving vegetation change whereas temperature becomes more important at higher altitudes. The combined reconstruction of biome‐scale vegetation dynamics in Colombia allows an understanding of the environmental controls on these to be developed that demonstrates the need to invoke different factors to explain the vegetation change rather than a uniform reduction in temperature or moisture. Copyright © 2004 John Wiley & Sons, Ltd.
Observations on Late Pleistocene cooling and precipitation in the lowland Neotropics
Authors: Bush Mark B. , Silman Miles R. 
Published: September 2004

AbstractAlthough accurate reconstructions of Amazonian palaeoclimates are central to understanding the distribution and history of Neotropical biodiversity, current reconstructions based on proxy data are discordant and subject to intense debate. We review some current thinking in Amazonian climatology and incorporate some new ideas in an attempt to explain the apparently contradictory records of palaeoprecipitation from across the Amazon Basin. We suggest that palaeoecologists need to recognise that organised convective radiation, the process that induces most wet season rainfall in Amazonia, should be treated as a phenomenon related to, but separate from, the passage of the inter‐tropical convergence zone (ITCZ). Decoupling ITCZ migration from larger convective activity provides a mechanism to account for observed palaeoclimatic heterogeneity. Patterns of observed precipitation change are consistent with the long‐term persistence of closed forest across much of Amazonia, indicating that the greatest changes in precipitation during the last glacial maximum came during the wet season, which would have little negative impact on forest extent. Neotropical cooling at the last glacial maximum (LGM) is widely accepted, although the estimates of that cooling range between 1°C and > 5°C. In answering the basic question ‘What is meant by cooling?’ we observe that interhemispheric ice mass asymmetry may have caused cooling to be manifested differently according to location. A terrestrial cooling of ca. 5°C, as well as radiative cooling and event‐based cooling combined to induce vegetation change. Probably, both absolute temperature and mean monthly minima were reduced by polar air incursions in the northern Neotropics. However, in the southern Neotropics, mean monthly minima were reduced by more frequent incursions of Patagonian air masses, but absolute minima may have been largely unchanged. Copyright © 2004 John Wiley & Sons, Ltd.
Assessment of the Neotropical dry forest refugia hypothesis in the light of palaeoecological data and vegetation model simulations
Authors: Mayle Francis E. 
Published: September 2004

AbstractSeasonally dry tropical forests exhibit a markedly discontinuous, disjunct distribution pattern across South America. Previous botanical inventories have revealed that these dry forest areas exhibit close floristic links with one another, which has led to the hypothesis that they constitute modern‐day refugia, resulting from vicariance (i.e. fragmentation) of a formerly more widespread, continuous distribution during more arid climatic conditions associated with the Last Glacial Maximum (LGM). This paper examines the validity of this ‘dry forest refugia’ hypothesis in the light of previously published fossil pollen data and vegetation model simulations. The model simulations suggest that major dry forest areas, such as the Bolivian Chiquitano Dry Forest, are not Pleistocene refugia, but instead developed during the Holocene by population expansions from parts of southern Amazonia presently covered by evergreen rainforest. The limited pollen data available indicate that glacial‐age seasonally dry tropical forests, irrespective of their distribution, were floristically quite different from those of today, with key dry forest species, such as Anadenanthera, only appearing in the Holocene. I suggest that a more parsimonious explanation for the current biogeographic pattern of these South American dry forests is population migration (perhaps by long‐distance dispersal) since the LGM, rather than vicariance. Copyright © 2004 John Wiley & Sons, Ltd.
Vibrational spectral studies of (β‐alanine) β‐alaninium nitrate
Authors: Jinnah M. Mohamed Ali , Umadevi M. , Ramakrishnan V. 
Published: September 2004

AbstractLaser Raman and infrared spectra of (β‐alanine) β‐alaninium nitrate were recorded and analyzed at room temperature. The proposed assignment of normal modes is based on group theoretical analysis. The hydrogen atom is shared by two amino acids, leading to switching of roles of the cation and zwitterion. The two alanine groups share one proton and become monoprotonated. The presence of an ionized carboxylic group and carbonyl was identified. The extensive hydrogen bonding in the crystal is responsible for the changes in the position and intensity of several bands. The nitrate anion fundamentals, however, continue to be degenerate. Copyright © 2004 John Wiley & Sons, Ltd.
Thermochemical properties from G3MP2B3 calculations, Set‐2: Free radicals with special consideration of CH2CHC•CH2, cyclo−•C5H5, •CH2OOH, HO•CO, and HC(O)O•
Authors: Janoschek R. , Rossi M. J. 
Published: September 2004

AbstractAfter a set of 32 free radicals was presented (Int J Chem Kin 34, 550–560, 2002), an additional 60 free radicals (Set‐2) were studied and characterized by energy minimum structures, harmonic vibrational wave numbers ωe, moments of inertia IA, IB, and IC, heat capacities Cop(T), standard entropies So(T), thermal energy contents Ho(T) − Ho(0), and standard enthalpies of formation ΔfHo(T) at the G3MP2B3 level of theory. Thermodynamic functions at T = 298.15 K are presented and compared with recent experimental values where these are available. The mean absolute deviation between calculated and experimental ΔfHo(298.15) values by the previous set of 32 radicals is 3.91 kJ mol−1. For the sake of comparison, only 49 species out of the 60 radicals of Set‐2 are characterized by experimental enthalpies of formation, and the corresponding mean absolute deviation between calculated and experimental ΔfHo(298.15) values is 8.96 kJ mol−1. This situation is cause for demand of more and also more accurate experimental values. In addition to the above properties, parent molecules of a large set of the respective radicals are calculated to obtain bond dissociation energies Do(298.15). Radical stabilization owing to resonance is discussed using the complete sets of total atomic spin densities ρ as a support. In particular, a short review about recent developments of the first‐order Jahn–Teller radical c‐C5H5• is presented. In addition, radicals with negative bond energies are described, such as •CH2OOH where the reaction path to CH2O + HO• has been calculated, as well as radicals which have two different parent molecules, for example CNO•. For the reaction HO• + CO → H• + CO2, two reaction paths are characterized by a total of 14 stationary points where the intermediate radicals HO•CO and HC(O)O• are involved. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 661–686, 2004
UV‐Curable Organic‐Inorganic Hybrid Film Coatings Based on Epoxidized Cyclohexene Derivatized Linseed Oil
Authors: Zou Kunrong , Soucek Mark D. 
Published: September 2004

AbstractSummary: Organic‐inorganic hybrid films based on epoxidized cyclohexene derivatized linseed oil (ECLO) and tetraethylorthosilicate (TEOS) oligomers were prepared via a UV‐curing process. The kinetics of the hybrid materials were studied by photo‐differential scanning calorimetry (DSC). In addition to the kinetics, the tensile properties, pencil hardness, pull‐off adhesion, reverse impact resistance, solvent resistance and abrasion resistance of the hybrid coatings were evaluated. Both dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA) were used to investigate the viscoelastic and thermal properties of the hybrid films. The morphology of the hybrid film was characterized by atomic force microscopy (AFM). Based on the results from the aforementioned evaluation of the coatings, the hybrid films exhibited higher pencil hardness, tensile strength, tensile modulus, fracture toughness, abrasion resistance, cross‐link density and thermal stability compared to the ECLO organic film. The Photo‐DSC data showed that the photo‐curing speed of the hybrid materials increased with TEOS oligomers content. It was postulated that the TEOS oligomers were reactive diluents.Structure of ECLO.magnified imageStructure of ECLO.
Studies on Molecular Composites of Polyamide 6/Polyamide 66
Authors: Li Yulin , Yang Guisheng 
Published: September 2004

AbstractSummary: A series of molecular composites of PA 6/PA 66 was synthesized via in situ polymerization. The impact resistance of PA 6 was improved dramatically by incorporating a minor amount of PA 66 (2–10 wt.‐%), without decreasing the tensile strength. Inserting PA 66 macromolecules at a molecular level into a PA 6 matrix may interfere with the arrangement of the hydrogen bonds of PA 6, in turn changing the crystalline structure and impeding the crystallization of PA 6.SEM micrograph of the fractured surface of a PA 6/PA 66 composite containing 10 wt.‐% PA 66.imageSEM micrograph of the fractured surface of a PA 6/PA 66 composite containing 10 wt.‐% PA 66.
Simple Preparation of Sulfate Anion‐Doped Polyaniline‐Clay Nanocomposites by an Environmentally Friendly Mechanochemical Synthesis Route
Authors: Yoshimoto Shoji , Ohashi Fumihiko , Kameyama Tetsuya 
Published: September 2004

AbstractSummary: Conducting polyaniline (PANI) and montmorillonite (MMT) nanocomposites were prepared from aniline sulfate and MMT by a mechanochemical synthesis route. X‐Ray diffraction analysis confirmed that, by controlling the aniline sulfate content, mechanochemical synthesis led to two types of different formations. After polymerization, the mechanochemical route synthesized much more PANI between the clay layers compared to a solution method. The electrical conductivities of the synthesized PANI‐MMT nanocomposites in pressed pellets ranged in the order of between 10−4 and 10−3 S · cm−1.X‐ray powder diffraction patterns of the intercalation products prepared by grinding montmorillonite with various amounts of Ani‐SO4 in a mortar.imageX‐ray powder diffraction patterns of the intercalation products prepared by grinding montmorillonite with various amounts of Ani‐SO4 in a mortar.
Electron Transfer Reactions of Radical Anions with TEMPO: A Versatile Route for Transformation of Living Anionic Polymerization into Stable Radical‐Mediated Polymerization
Authors: Cianga Ioan , Senyo Takamichi , Ito Koichi , Yagci Yusuf 
Published: September 2004

AbstractSummary: The possibility of transforming a living anionic polymerization into a stable radical‐mediated radical polymerization (SFRP) was demonstrated. For this purpose, 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) alcoholate, formed by a one‐electron redox reaction between potassium naphthalene and TEMPO, was used to initiate the living anionic polymerization of ethylene oxide (EO). Poly(ethylene oxide) obtained in this way possessed TEMPO terminal units and was subsequently used as an initiator for the SFRP of styrene to give block copolymers.A one‐electron redox reaction gives rise to TEMPO alcoholate, which is able to initiate the living anionic polymerization of ethylene oxide (EO).imageA one‐electron redox reaction gives rise to TEMPO alcoholate, which is able to initiate the living anionic polymerization of ethylene oxide (EO).
(Star PS)‐block‐(Linear PI)‐block‐(Star PS) Triblock Copolymers – Thermoplastic Elastomers with Complex Branched Architectures
Authors: Huang Tianzi , Knauss Daniel M. 
Published: September 2004

AbstractPolystyrene‐block‐polyisoprene‐block‐polystyrene triblock copolymers were synthesized with star‐shaped branching in the polystyrene phase. The block copolymers were formed through sequential anionic polymerization by first synthesizing linear polystyrene, followed by star coupling using 4‐(chlorodimethylsilyl)styrene, then the polymerization of isoprene, followed by difunctional coupling with dichlorodimethylsilane. The polymerization was followed by gel permeation chromatography and the resulting copolymers were characterized by 1H NMR spectroscopy to examine the polyisoprene microstructure.
Synthesis of Poly(1,3‐cyclohexadiene) Containing Star‐Shaped Elastomers
Authors: Williamson D.T. , Long T.E. 
Published: September 2004

AbstractThe synthesis of high molecular weight star‐shaped polymers comprising poly(1,3‐cyclohexadiene‐block‐isoprene) diblock arms coupled to a divinyl benzene (DVB) core is reported. The number average molecular weights of the diblock arms were varied from 30000 to 50000 and the ratio of DVB to n‐butyllithium (nBuLi) was systematically varied from 3:1 to 12:1. Size exclusion chromatography coupled with light scattering detection was utilized to detect the formation of star‐shaped polymers and the presence of star‐star coupling. The molecular weight distribution (<Mw>/<Mn>) of the star polymers ranged from 1.25 to 1.50. The effect of poly(1,3‐cyclohexadiene) content on the mechanical properties of these novel elastomers is reported. The elastic modulus, elongation at break, and tensile strength of these elastomers were all found to be a function of the percentage of poly(1,3‐cyclohexadiene). The glass transition temperatures were determined using both differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Atomic force microscopy was performed in the tapping mode (TMAFM) to verify the presence of microphase separation.
Triblock and Radial Star‐Block Copolymers Comprised of Poly(ethoxyethyl glycidyl ether), Polyglycidol, Poly(propylene oxide) and Polystyrene Obtained by Anionic Polymerization Initiated by Cs Initiators
Authors: Dimitrov Ph. , Rangelov St. , Dworak A. , Haraguchi N. , Hirao A. , Tsvetanov Ch.B. 
Published: September 2004

AbstractThe anionic polymerization of ethoxyethyl glycidyl ether (EEGE) initiated by cesium alkoxide was studied. The ring‐opening polymerization of EEGE in the presence of cesium alkoxide of 1‐methoxy‐2‐ethanol does not involve any side reactions. The presence of an additional alcohol leads to a significant increase of the initiator efficiency.Aqueous solutions of poly (ethoxyethyl glycidyl ether) (PEEGE) exhibit lower critical solution temperature (LCST), and the polymer solubility in water is extremely sensitive to its MW. Two novel types of block copolymers based on PEEGE were synthesized: triblock‐copolymers of ABA (A′:BA′) structure, where A is the PEEGE block, A′ polyglycidol (PG) and B the polypropylene oxide (PPO) block, and A2S (A′2S) and A4S (A′4S) heteroarm stars, where S is the polystyrene block.The synthesis of the ABA block was performed by polymerization of EEGE initiated by bi‐functional PPO/Cesium alkoxide macroinitiator. The PEEGE blocks were converted into PG blocks by successful cleavage of the ethoxyethyl group.Polystyrene/PEEGE and polystyrene/PG three‐ and five‐ heteroarm star copolymers were synthesized by a coupling reaction between well‐defined chain‐end‐functionalized polystyrenes carying dendritic benzyl bromide moieties with living anionic polymers of PEEGE with one cesium alkoxide terminal group. The coupling reaction proceeds quantitatively without any side reactions, and thus series of star‐branched polymers can be systematically synthesized. Polystyrenes with two or four PG arms have been obtained after the cleavage of the protecting group. The compact structure of these multi‐arm star polymers and their amphiphilic character leads to the formation of nanoparticles in aqueous solution with rather uniform size distribution and a mean diameter of 15 nm.
Telechelic Polyisobutenes with Asymmetrical Reactivity
Authors: Lange Arno , Rath Hans‐Peter , Lang Gabriele 
Published: September 2004

Abstract3‐Chlorocyclopentene‐(1) has been used as initiator in the quasiliving cationic polymerization of isobutene. Polyisobutenes in the molecular weight range Mw = 300 ‐ 60000 Dalton with a molecular weight distribution MWD between 1.17 and 1.34 have been synthesized. The linear polymer was selectively hydrosilated on one or both ends. With a furan coupling agent, the PIB (polyisobutene) was dimerized, yielding polymers with a cyclopentene head‐ and tail group.