bluuebunny/crossref_metadata_2025 huggingface dataset:
Stable and Sensitive Electrochemical Detection of Phenolic Compounds at Carbon Nanotube Modified Glassy Carbon Electrodes
Authors: Wang Joseph , Deo Randhir P. , Musameh Mustafa
Published: December 2003

Carbon‐nanotube modified glassy‐carbon electrodes are used for enhancing the stability and sensitivity of voltammetric and amperometric measurements of phenolic compounds. Cyclic voltammetric experiments indicate that the redox process involves the formation of a surface‐confined layer that promotes (rather than inhibits) the phenol oxidation. The amperometric response of the coated electrodes is highly stable, with 85% of the initial activity remaining after 30 min stirring of a 2×10−4 M phenol solution (compared to complete inhibition of the redox process within 6 min at the bare surface). Similar stability improvements were observed for different phenolic compounds and different concentrations of such compounds. The modified electrodes display greatly enhanced current signals in cyclic voltammetric and amperometric experiments.
A computational Lagrangian–Eulerian advection remap for free surface flows
Authors: Ashgriz Nasser , Barbat Tiberiu , Wang Gang
Published: December 2003

A VOF‐based algorithm for advecting free surfaces and interfaces across a 2‐D unstructured grid is presented. This algorithm is based on a combination of a Computational Lagrangian–Eulerian Advection Remap and the Volume of the Fluid method (CLEAR‐VOF). A set of geometric tools are used to remap the advected shape of the volume fraction from one cell onto the Eulerian fixed unstructured grid. The geometric remapping is used to compute the fluxes onto a group of neighbouring cells of the mesh. These fluxes are then redistributed and corrected to satisfy the conservation of mass. Here, we present methods for developing identification algorithms for surface cells and incorporating them with CLEAR‐VOF. The CLEAR‐VOF algorithm is then tested for translation of several geometries. It is also incorporated in a finite element based flow solver and tested in a laminar flow over a broad‐crested weir and a turbulent flow over a semi‐circular obstacle. Copyright © 2004 John Wiley & Sons, Ltd.
Stability analysis of abnormal multiplication of plankton using parameter identification technique
Authors: Ohno G. , Kawahara M.
Published: December 2003

This paper presents the mathematical approach for the abnormal multiplication of plankton. An abnormal multiplication can be expressed as an unstable problem and the stability of the system is investigated by introducing eigenvalues of a mathematical equation. The stability of the system can be judged by an eigenvalue based on the Lyapunov's stability theory. In this paper, the Arnoldi‐QR method is used to obtain eigenvalues and eigenvectors of the system. The mode superposition method is employed to create spatial distribution needed to analyse the stability. To obtain the objective eigenvalue, the parameter identification technique is employed. The finite element method is used for the discretization in space. Lake Kasumigaura, which is located in Ibaraki Prefecture in Japan, is selected and actual data in 1975, 1976, 1991 and 2000 are used in order to investigate the stability of the specified lake in Japan. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of [18F]3‐[1‐(3‐fluoropropyl)‐(S)‐pyrrolidin‐2‐ylmethoxy]pyridine ([18F]NicFP): a potential α4β2 nicotinic acetylcholine receptor radioligand for PET
Authors: Dumont Filip , Sultana Abida , Balter Andrew , Waterhouse Rikki N.
Published: December 2003

Nicotinic acetylcholine receptors are widely distributed throughout the human brain and are believed to play a role in several neurological and psychiatric disorders. In order to identify an effective PET radioligand for in vivo assessment of the α4β2 subtype of nicotinic receptor, we synthesized [18F]3‐[1‐(3‐fluoropropyl)‐(S)‐pyrrolidin‐2‐ylmethoxy]pyridine (NicFP). The in vitro KD of NicFP was determined to be 1.1 nM, and the log P value obtained by HPLC analysis of the unlabelled standard was found to be 2.2. The radiosynthesis of [18F]NicFP was carried out by a nucleophilic substitution reaction of anhydrous [18F]fluoride and the corresponding mesylate precursor. After purification by HPLC, the radiochemical yield was determined to be 11.3±2.1% and the specific activity was 0.47±0.18 Ci/μmol (EOS, n = 3). The time of synthesis and purification was 99±2 min. The final product was prepared as a sterile saline solution suitable for in vivo use. Copyright © 2003 John Wiley & Sons, Ltd.
Holocene seasonal sea‐surface temperature variations in the southern Adriatic Sea inferred from a multiproxy approach
Authors: Sangiorgi Francesca , Capotondi Lucilla , Combourieu Nebout Nathalie , Vigliotti Luigi , Brinkhuis Henk , Giunta Simona , Lotter Andrè F. , Morigi Caterina , Negri Alessandra , Reichart Gert‐Jan
Published: December 2003

Holocene cooling events have been reconstructed for the southern Adriatic Sea (central Mediterranean) by means of analyses of organic walled dinoflagellate cysts, planktonic foraminifera, oxygen isotopes, calcareous nanoplankton, alkenones and pollen from a sediment core. Two cooling events have been detected, during which sea‐surface temperatures (SSTs) were ca. 2°C lower. Unravelling the SST signal into dominant seasonal components suggests maximum winter cooling of 2°C at around 6.0 ka, whereas the cooling at ca. 3.0 ka might be the result of a spring temperature cooling of 2–3°C. The events, lasting several hundred years, are apparently synchronous with those in the Aegean Sea, where they have been related to known cooling events from the Greenland ice‐core record. A distinct interruption in Adriatic Sea sapropel S1 is not clearly accompanied by a local drop in winter temperatures, but seems to be forced by ventilation, which probably occurred earlier in the Aegean Sea and was subsequently transmitted to the Adriatic Sea. Copyright © 2003 John Wiley & Sons, Ltd.
Quaternary palaeoceanographic changes in the northern South China Sea (ODP Site 1146): radiolarian evidence
Authors: Wang Rujian , Clemens Steven , Huang Baoqi , Chen Muhong
Published: December 2003

The abundance and accumulation rates of siliceous microfossils in the northern South China Sea, including radiolarians, diatoms and sponge spicules, increased during most glacial intervals within the past 1100 kyr. Similar trends are observed in the index of thermocline surface radiolarians (TSR), diatom accumulation rates (DAR), charcoal accumulation rates (CAR) and the abundance of radiolarian species Cycladophora davisiana davisiana. Decreasing sea‐surface temperature accompanied by increased seasonality since 900 ka is indicated by a decline in the tropical radiolarian assemblage, including Tetrapyle octacantha and Octopyle stenozona, and by an increase in the subtropical assemblage, including Pterocorys zancleus, Peromelissa phalacra and Ommatartuts tetrathalamus tetrathalamus. Rapid increases at about 800 to 700 ka of siliceous microfossils, charcoal, subsurface and intermediate radiolarians, as well as the TSR index and the DAR, imply a fundamental shift in climate and a shoaling thermocline. Although these fundamental changes in the silicious fauna and flora of the South China Sea take place within the context of a developing 100‐kyr cycle, they do not change in step with changing sea‐level as indicated by marine δ18O. This is most clearly illustrated by the step‐like increase in silica accumulation (radiolaria, diatoms and sponge spicules) at 680 ka. Rather, these fundamental changes probably reflect intensified surface productivity associated with enhanced East Asian winter‐monsoon circulation. Copyright © 2003 John Wiley & Sons, Ltd.
Geological and archaeological evidence of active faulting on the Martana Fault (Umbria–Marche Apennines, Italy) and its geodynamic implications
Authors: Bonini Marco , Tanini Chiara , Moratti Giovanna , Piccardi Luigi , Sani Federico
Published: December 2003

This paper examines the morphotectonic and structural–geological characteristics of the Quaternary Martana Fault in the Umbria–Marche Apennines fold‐and‐thrust belt. This structure is more than 30 km long and comprises two segments: a N–NNW‐trending longer segment and a 100°N‐trending segment. After developing as a normal fault in Early Pleistocene times, the N–NNW Martana Fault segment experienced a phase of dextral faulting extending from the Early to Middle Pleistocene boundary until around 0.39 Ma, the absolute age of volcanics erupted in correspondence to releasing bends. The establishment of a stress field with a NE–ENE‐trending σ3 axis and NW–NNW σ1 axis in Late Pleistocene to Holocene times resulted in a strong component of sinistral faulting along N–NNW‐trending fault segments and almost pure normal faulting on newly formed NW–SE faults. Fresh fault scarps, the interaction of faulting with drainage systems and displacement of alluvial fan apexes provide evidence of the ongoing activity of this fault. The active left‐lateral kinematic along N–NNW‐trending fault segments is also revealed by the 1.8 m horizontal offset of the E–W‐trending Decumanus road, at the Roman town of Carsulae. We interpret the present‐day kinematics of the Martana Fault as consistent with a model connecting surface structures to the inferred north‐northwest trending lithospheric shear zone marking the western boundary of the Adria Plate. Copyright © 2003 John Wiley & Sons, Ltd.
Geomorphological markers of faulting and neotectonic activity along the western Andean margin, northern Chile
Authors: Audin Laurence , Herail Gérard , Riquelme Rodrigo , Darrozes José , Martinod Joseph , Font Eric
Published: December 2003

In the Atacama Desert, northern Chile, some ephemeral channels are developed in the Plio‐Quaternary alluvial sequence that caps the Neogene Atacama Gravels Formation. Geomorphological studies and high‐resolution digital elevation data (GPS) along a structural transect in the Central Depression are used to document modern growth history of subtle folding and faulting in the fore‐arc region. Outcrop data of the most recent deposits are combined with observations of warped and faulted late Quaternary pediments, alluvial fans and terrace surfaces to propose unsuspected neotectonic processes on the western flank of the Domeyko Cordillera. Neotectonic process recognition is here based largely upon the interpretation of alluvial landforms, drainage organisation and evolution as the intermittent river network shows systematic patterns of course deflections, successive incisions or deposition processes as it encounters the fault scarps or folds in the superficial deposits. This area presents both N–S‐trending active vertical faults in the topographically higher pampas, and N–S‐trending active folding in the lower pampas. These faults seem to accommodate E–W extension and compression that could be related to uplift of the western Andean margin within a compressive context. Uplift may have taken place unevenly over the past few million years after the deposition of the superficial alluvial surfaces that cap the Neogene Atacama Gravels. Copyright © 2003 John Wiley & Sons, Ltd.
Geomorphological palaeoenvironments of the Sneeuberg Range, Great Karoo, South Africa
Authors: Holmes P. J. , Boardman J. , Parsons A. J. , Marker M. E.
Published: December 2003

Sedimentary sequences within headwater valleys on the landward side of the Great Escarpment of South Africa are elucidated and their significance as indicators of environmental change is assessed. This study focuses on the Sneeuberg Range, the most prominent mountain range in the semi‐arid central Great Karoo. Valley fills of a hitherto unrecognised complexity and of a greater age than any previously recorded in the central Great Karoo are reported. Three phases of deposition spanning the Late Pleistocene up to the present are documented from sites where gully erosion has incised the valley fills. The earliest depositional phase is represented by deeply weathered, calcretised gravel deposits, which probably were emplaced by debris flow and fluvial processes in the form of a fan. These deposits subsequently were buried by finer grained, largely unconsolidated sediment, with much of this emplacement occurring during the Holocene. There is evidence for phases of landscape stability and instability within this facies. Finally, sheetwash has removed fine‐grained sediments from valley flanks and has deposited it either on valley bottoms, or in presently active gullies. This process appears to be ongoing, and is the subject of current investigation. The sedimentary deposits are interpreted as representing a wide range of palaeoenvironmental conditions that have prevailed within the central Great Karoo since the penultimate glaciation. Copyright © 2003 John Wiley & Sons, Ltd.
Abrupt vegetation changes during the last glacial to Holocene transition in mid‐latitude South America
Authors: Moreno Patricio I. , León Ana L.
Published: December 2003

A pollen record from the Huelmo site (ca. 41°30′S) shows that vegetation and climate changed at millennial time‐scales during the last glacial to Holocene transition in the mid‐latitude region of western South America. The record shows that a Nothofagus parkland dominated the landscape between 16 400 and 14 600 14C yr BP, along with Magellanic Moorland and cupressaceous conifers. Evergreen North Patagonian rainforest taxa expanded in pulses at 14 200 and 13 000 14C yr BP, following a prominent rise in Nothofagus at 14 600 14C yr BP. Highly diverse, closed canopy rainforests dominated the lowlands between 13 000 and 12 500 14C yr BP, followed by the expansion of cold‐resistant podocarps and Nothofagus at ca. 12 500 and 11 500 14C yr BP. Local disturbance by fire favoured the expansion of shade‐intolerant opportunistic taxa between 10 900 and 10 200 14C yr BP. Subsequent warming pulses at 10 200 and 9100 14C yr BP led to the expansion of thermophilous, summer‐drought resistant Valdivian rainforest trees until 6900 14C yr BP.

Our results suggest that cold and hyperhumid conditions characterised the final phase of the Last Glacial Maximum (LGM), between 16 400 and 14 600 14C yr BP. The last ice age Termination commenced with a prominent warming event that led to a rapid expansion of North Patagonian trees and the abrupt withdrawal of Andean ice lobes from their LGM positon at ca. 147 000 14C yr BP. Hyperhumid conditions prevailed between 16 400 and 13 000 14C yr BP, what we term the ‘extreme glacial mode’ of westerly activity. This condition was brought about by a northward shift and/or intensification of the southern westerlies. The warmest/driest conditions of the last glacial–interglacial transition occurred between 9100 and 6900 14C yr BP. During this period, the westerlies shifted to an ‘extreme interglacial mode’ of activity, via a poleward migration of stormtracks. Our results indicate that a highly variable climatic interval lasting 5500 14C years separate the opposite extremes of vegetation and climate during the last glacial‐interglacial cycle, i.e. the end of the LGM and the onset of the early Holocene warm and dry period. Copyright © 2003 John Wiley & Sons, Ltd.
Southwest Scandinavia, 40–15 kyr BP: palaeogeography and environmental change
Authors: Houmark‐Nielsen Michael , Henrik Kjær Kurt
Published: December 2003

Twelve palaeogeographical reconstructions illustrate environmental changes at the southwest rim of the Scandinavian Ice Sheet 40–15 kyr BP. Synchronised land, sea and glacier configurations are based on the lithostratigraphy of tills and intertill sediments. Dating is provided by optically stimulated luminescence and calibrated accelerator mass spectrometry radiocarbon.

An interstadial sequence ca. 40–30 kyr BP with boreo‐arctic proglacial fjords and subarctic flora and occasional glaciation in the Baltic was succeeded by a Last Glacial Maximum sequence ca. 30–20 kyr BP, with the closure of fjords and subsequent ice streams in glacial lake basins in Kattegat and the Baltic. Steadily flowing ice from Sweden bordered the Norwegian Channel Ice Stream. A deglaciation sequence ca. 20–15 kyr BP indicates the transgression of arctic waters, retreat of the Swedish ice and advance of Baltic ice streams succeeded by a return to interstadial conditions.

When ameliorated ice‐free conditions prevailed in maritime regions, glaciers advanced through the Baltic and when interstadial regimes dominated the Baltic, glaciers expanded off the Norwegian coast. The largest glacier extent was reached in the North Sea around 29 kyr BP, about 22 kyr BP in Denmark and ca. 18 kyr BP in the Baltic. Our model provides new data for future numerical and qualitative landform‐based models. Copyright © 2003 John Wiley & Sons, Ltd.
Femtosecond optical harmonic generation as a non‐linear spectroscopic probe for carbon nanotubes
Authors: Konorov S. O. , Akimov D. A. , Ivanov A. A. , Alfimov M. V. , Botti S. , Ciardi R. , De Dominicis L. , Asilyan L. S. , Podshivalov A. A. , Sidorov‐Biryukov D. A. , Fantoni R. , Zheltikov A. M.
Published: December 2003

Second‐ and third‐harmonic generation in single‐wall carbon nanotube layers produced by low‐velocity spraying was studied experimentally with the use of amplified 75 fs pulses of Cr:forsterite laser radiation within the range of pump pulse intensities up to the breakdown threshold. Harmonic‐generation processes are shown to be ideally suited for the non‐linear spectroscopy and structure analysis of carbon nanotubes, in many ways supplementary to Raman spectroscopy. The second‐ and third‐harmonic yields scale as quadratic and cubic functions, respectively, of the pump pulse energy up to pump intensities of 1012 W cm−2, indicating the perturbative regime of non‐linear‐optical interactions and suggesting a convenient calibration for the second and third harmonics employed as spectroscopic probes. Comparison of harmonic‐generation data with absorption spectra of carbon‐nanotube layers reveals an important role of quantum confinement effects in the non‐linear coherent scattering of light from carbon nanotubes. Femtosecond pulses of Cr:forsterite laser radiation also generate the fifth optical harmonic at 251 nm in the glass substrate of carbon‐nanotube samples, which can be employed for UV spectroscopy and subwavelength‐resolution non‐linear microscopy of carbon nanotubes. Copyright © 2003 John Wiley & Sons, Ltd.
Stimulated emission pumping by two‐color resonant four‐wave mixing: rotational characterization of vibrationally excited HCO (X̃2A′)
Authors: Radi P. P. , Tulej M. , Knopp G. , Beaud P. , Gerber T.
Published: December 2003

Stimulated emission pumping by applying two‐color resonant four‐wave mixing was used to measure rotationally resolved spectra of the HCO (0,0,0) B̃2A′–(0, 3, 1)X̃2A′ transition. The formyl radical is produced by photodissociation of formaldehyde at 31710.8 cm−1 under thermalized conditions in a low‐pressure cell. In contrast to the highly congested one‐color spectrum of HCO at room temperature, the double‐resonance method yields well isolated transitions which are assigned unambiguously owing to intermediate level labeling. Eighty‐nine rotational transitions were assigned and yield accurate rotational constants for the vibrationally excited (0,3,1) band of the electronic ground state X̃2A′ of HCO. The determined rotational constant A = 25.84 ± 0.01 cm−1 is considerably higher than that for the vibrationless ground state and reflects the structural change due to excitation of the bending mode of the formyl radical. Copyright © 2003 John Wiley & Sons, Ltd.
DFWM: a proposed method to measure χ(3) on carbon nanotubes on the nanosecond time‐scale
Authors: Botti S. , Ciardi R. , De Dominicis L. , Fantoni R. , Asilyan L. S. , Fiori A. , Appolloni R.
Published: December 2003

We have investigated the third order nonlinear optical properties of carbon nanotubes thick films. Nanosecond Degenerate Four Wave Mixing (DFWM) measurements have been performed at 532 and 355 nm yielding effective χ(3) values of the order of 10−11 esu. and indicating the resonant nature of the excitation involved. The determination of the CNTs sample density by means of Scanning Electronic Microscope technique allowed to relate sample bulk properties like χ(3) to the single CNT second order polarizability coefficient. Copyright © 2003 John Wiley & Sons, Ltd.
Advanced instrumentation for non‐linear Raman microscopy
Authors: Yakovlev V. V.
Published: December 2003

Over the past several years, there was a renaissance of non‐linear Raman microscopy based on coherent anti‐Stokes Raman spectroscopy. We propose and experimentally implement a novel approach to construct an apparatus for non‐linear Raman imaging. The complete set‐up can be constructed for <$50 000 and can be used for a large variety of spectroscopic applications including CARS microscopy and non‐linear optical sensing. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of theortho‐/paradeuterium concentration ratio with femtosecond CARS
Authors: Knopp G. , Kirch K. , Beaud P. , Mishima K. , Spitzer H. , Radi P. , Tulej M. , Gerber T.
Published: December 2003

The time‐resolved femtosecond coherent anti‐Stokes Raman scattering (CARS) method was used for the determination ofpara‐ andortho‐states in gaseous deuterium (D2). The present investigations at the SINQ (‘Spallations Neutronen Quelle’) spallation neutron source at the Paul Scherer Institute (PSI) were performed for the development of an effective ultra‐cold neutron (UCN) source. High concentrations ofortho‐D2in UCN sources are mandatory and therefore flexible applications for the measurement ofortho‐D2concentrations are of interest. Hence the non‐equilibriumortho‐D2concentration in gas samples, taken from the liquid D2cold moderator of the SINQ, was measured with fs‐CARS. It is shown that the sensitivity of fs‐CARS due to the nuclear spin degeneracy is high, and that the method is an ideal tool for D2para‐ andortho‐state investigations. At a sample temperature of 298 K theortho‐D2concentration for thermalized D2was measured as 66.664(16)% of the total D2concentration, whereas the fraction ofortho‐D2molecules in a specific sample from the spallation source was found to be 70.68(33)%. Copyright © 2003 John Wiley & Sons, Ltd.
High‐pressure pure rotational CARS: comparison of temperature measurements with O2, N2 and synthetic air
Authors: Seeger T. , Beyrau F. , Bräuer A. , Leipertz A.
Published: December 2003

The accuracy of pure rotational coherent anti‐Stokes Raman spectroscopy (CARS) temperature measurements was investigated using O2, N2 and synthetic air for comparison. These measurements were performed in a high‐pressure cell for pressures between 0.1 and 15 MPa. The cell temperature was varied between 300 to 700 K. The temperature values deduced from the pure rotational CARS S‐branch of O2 are in good agreement with the reference thermocouple reading. For the temperature and pressure range investigated, the accuracy for O2 measurements was better than that obtained for N2 and synthetic air. Copyright © 2003 John Wiley & Sons, Ltd.
Linewidths and shifts of carbon dioxide CARS spectra near the critical point
Authors: Arakcheev V. G. , Bagratashvili V. N. , Valeev A. A. , Gordiyenko V. M. , Kireev V. V. , Morozov V. B. , Olenin A. N. , Popov V. K. , Tunkin V. G. , Yakovlev D. V.
Published: December 2003

Transformation of the Q‐branch in CARS spectra of the low‐wavenumber Fermi dyad 2ν2/ν1 component was studied in CO2 near the critical point (Tc = 31.03 °C, Pc = 72.8 atm). CARS spectra were collected along several isotherms in the temperature and pressure ranges 25.6–36.1 °C and 48–118 atm, respectively. The dependence of linewidth on pressure has an extremum at temperatures >31 °C with a maximum linewidth ∼50% greater than in liquid CO2. The position of the maximum was shifted from the critical to higher pressure with temperature increase. Interpretation of this inhomogeneous broadening is given in terms of cluster microstructure of the supercritical fluid. Copyright © 2003 John Wiley & Sons, Ltd.
Saturation effects in molecular spectroscopy using degenerate four‐wave mixing
Authors: Bultitude K. , Bratfalean R. , Ewart P.
Published: December 2003

Lineshapes of degenerate four‐wave mixing signals induced by both monochromatic and non‐monochromatic lasers are compared with predictions of the non‐perturbative model of Bratfalean, Lloyd and Ewart (BLE model) for the interaction of pump and probe beams of arbitrary intensity. Spectral lineshapes of isolated lines in DFWM spectra of OH in a methane–oxygen flame were recorded using a novel single‐mode tunable laser as a function of laser power. Power broadening of the lineshapes was found, in this case of an essentially monochromatic laser, to be well described by the BLE model. DFWM lineshapes of more complex molecular spectra were recorded in C2 in an oxy–acetylene flame using a standard, non‐monochromatic, dye laser. Lineshapes of closely spaced molecular resonances were found to be appreciably affected by saturation or power broadening effects. These effects were reasonably well approximated by the non‐perturbative BLE model when adapted to take account of the finite laser bandwidth. In contrast, the experimental lineshapes of the C2 spectra for saturating fields could not be modeled using the standard perturbative model of Abrams and Lind Copyright © 2003 John Wiley & Sons, Ltd.
Precision of single‐shot dual‐broadband rotational CARS thermometry with single‐mode and multi‐mode Nd:YAG lasers
Authors: Afzelius M. , Bengtsson P.‐E.
Published: December 2003

The precision of single‐shot coherent anti‐Stokes Raman spectroscopy (CARS) thermometry is an important characteristic for the application of CARS in various combustion devices such as internal combustion engines. It is generally assumed that the precision of CARS is directly related to the spectral noise of the interacting laser fields, and previous studies have presented a theoretical model describing the behaviour of the noise as a function of various experimental parameters. In this work, the aim was to test the results predicted by the previously developed model for dual‐broadband rotational CARS. We studied the precision of evaluated temperatures in pure nitrogen under different experimental conditions, namely the dependence of precision on the gas pressure and on the linewidth of the narrowband laser (the Nd:YAG laser). It was demonstrated that our experiments reproduce the main features of the model, and that a single‐mode Nd:YAG laser leads to better precision than a multi‐mode Nd:YAG laser for dual‐broadband rotational CARS thermometry. Copyright © 2003 John Wiley & Sons, Ltd.
Note on utilisation of peanut seed testa
Authors: Sobolev Victor S , Cole Richard J
Published: December 2003

Peanut testae (skins, seed coats) are an extremely low value by‐product of peanut‐blanching operations. Their commercial value is $12–20 per ton and their limited use is only as a minor component of cattle feed. Based on world in‐shell peanut production of 29.1 million tons in 1999/2000 and an average skin content of 2.6%, world production of peanut skins can be estimated at over 750 000 tons annually. Research performed to find new uses for peanut skins demonstrated that up to 35% of the oil in the skins can be recovered. In some cases the oil can be a new potential source of behenic and lignoceric acids, which are used in body‐building formulations and as ingredients in shampoos. After removal of the oil the skins were useful for making brandy, liqueur and tea. Peanut skin oil extraction followed by tannin extraction also produces a protein‐enriched product that could find application in mixed feeds for cattle consumption at higher concentrations relative to existing practice. A simple technique was also offered to use the skins in finishing decorative panels. Published in 2003 for SCI by John Wiley & Sons, Ltd.
Changes in chemical quality indices during long‐term storage of palm‐olein oil under heated storage and transport‐type conditions
Authors: van der Merwe Gretel H , du Plessis Lourens M , Taylor John RN
Published: December 2003

Six quality indices, namely free fatty acids (FFA), peroxide value (PV), anisidine value (AV), oxidative stability index (OSI), total tocopherols and headspace volatiles (hexanal, t‐2‐hexenal and t,t‐2,4‐decadienal), were evaluated in a long‐term storage trial of 52 weeks at 50 °C of palm‐olein, a monounsaturated oil. Three concentrations of copper (0.035, 0.17 and 0.69 mg kg−1) were added. FFA values for all the sample treatments increased slightly over the storage period but remained within acceptable limits. PV of the copper‐containing samples declined initially and then remained stable up to week 40, after which it increased slightly for the 0.035 and 0.17 mg kg−1 samples. However, PV of the control (no added copper) increased steadily to above the acceptable limit. AV of the copper‐containing samples increased much more than that of the control. OSI and total tocopherol values of the copper‐containing samples were markedly lower than those of the control. t‐2‐Hexenal did not increase during the storage period, whereas hexanal increased in the copper‐containing samples but at a slower rate than in the control. Conversely, the copper‐containing samples had high levels of t,t‐2,4‐decadienal but the control had none. AV, OSI and total tocopherols are the most valuable quality indices for assessing monounsaturated oil quality, whereas FFA, PV and headspace volatiles can be misleading. Copyright © 2003 Society of Chemical Industry
Structural and physical properties of dried Anaheim chilli peppers modified by low‐temperature blanching
Authors: Heredia‐Léon JC , Talamás‐Abbud R , Mendoza‐Guzmán V , Solís‐Martinez F , Jimenez‐Castro J , Barnard J , Quintero‐Ramos A
Published: December 2003

The effect of low‐temperature blanching and drying processes on the ultrastructural and physical properties of Anaheim chilli pepper was studied and optimum conditions to provide a final product with maximum firmness were determined. Lots of Anaheim pepper were blanched in water for 4 min at 48, 55, 65, 75 and 82 °C and maintained for hold times of 35, 45, 60, 75 and 85 min, blanched again for 4 min at 96 °C and dehydrated at 53, 60, 70, 80 and 87 °C. After treatment the samples were rehydrated in water at 30 °C. Rehydration ratio, texture and structural changes were evaluated. Optimisation used a second‐order rotatable central composite design. Texture and rehydration ratio were affected by blanching temperature and the interaction of blanching temperature with hold time (p ≤ 0.05); drying temperature did not show a significant effect. The best results, ie those which gave greatest firmness, were obtained by blanching at 64 °C for 4 min, holding for 55 min after blanching, followed by a second blanching at 96 °C for 4 min and then drying at 70 °C. Evaluation of the rehydrated dried pepper by microscopy showed that low‐temperature blanching close to the optimum conditions provided a protective effect in maintaining cell wall integrity. The results of processing increased firmness in the rehydrated product by a factor of 1.97. Copyright © 2003 Society of Chemical Industry
Processing of soybean hulls to enhance the distribution and extraction of value‐added proteins
Authors: Sessa David J
Published: December 2003

Soybean hulls contain peroxidase (SBP) and Bowman–Birk type protease inhibitor (BBI). SBP is used in the European bread‐baking industry, and BBI isolated from dehulled, defatted soy flour possesses cancer‐preventive and anticarcinogenic properties. Because hulls possess a low percentage of nitrogen, with fibre and other carbohydrates being the major components, our objective was to determine whether air classification of milled hulls could be used to fractionate and enrich these value‐added proteins. Hulls were pin milled three times at 18 000 rpm, followed by air classification to yield fractions with particle size distributions ranging from <15 to >30 µm. The finely ground fractions with particle sizes ranging from <15 to 18 µm were enriched with nitrogen and lipid when compared with the more coarsely ground fractions. Yields of extractable nitrogenous components from aqueous extracts were quantified at a variety of pHs, homogenisation speeds and times. BBI and SBP were confirmed by polyacrylamide gel electrophoresis with known standards. Based on assays for SBP and BBI activities, BBI, though concentrated in the finer fractions, also appeared in the highest‐mass, coarsest fraction, whereas SBP resided mainly in the coarsest fraction. Dry milling and air classification of soybean hulls proved beneficial to distribute SBP into a product stream that facilitates its isolation and purification. Published in 2003 for SCI by John Wiley & Sons, Ltd.
Effect of high‐pressure processing on myofibrillar protein structure
Authors: Chapleau Nicolas , Mangavel Cécile , Compoint Jean‐Pierre , de Lamballerie‐Anton Marie
Published: December 2003

Modification of myofibrillar proteins induced by high‐pressure processing has been investigated at pressures ranging from 50 to 600 MPa for 10 min at 20 °C. Analysis by spectroscopic methods and circular dichroism of myofibrillar proteins in phosphate buffer pH 6.0 containing 0.6 M KCl showed no changes in the secondary structure of proteins. However, study of protein conformation by quasielastic light scattering and gel filtration chromatography proved the emergence of aggregation after treatment at pressures higher than 300 MPa. This aggregation was accompanied by enhanced binding of anilino‐1‐naphthalene‐8‐sulphonic acid, which indicated an increase in hydrophobic bonding of myofibrillar proteins. Modification of the tertiary and quaternary structures of proteins may induce a molten globule state. Copyright © 2003 Society of Chemical Industry
Solubilisation of proteins from rayfish residues by endogenous and commercial enzymes
Authors: Pastoriza Laura , Sampedro Gabriel , Cabo Marta L , Herrera Juan JR , Bernárdez Marta
Published: December 2003

The aim of the present study was to design methods for the digestion of fish proteins from processing wastes, leading to new possibilities for little‐used species or those generating a significant volume of residues. Residues of rayfish (Raja clavata) were used for the solubilisation of protein by hydrolysis treatment. The kinetics of hydrolysis was studied using rayfish enzymes, either by autolysis of the protein in a triturate of the raw material or by application of a multi‐enzyme preparation previously extracted from the viscera of the species. Their effectiveness was compared with that of two commercial enzymes, papain and pepsin. Optimum conditions of hydrolysis and enzymatic activity for digestion with rayfish enzymes were ascertained. The yield of material and the efficiency of digestion in each of the hydrolysis processes are reported. Copyright © 2003 Society of Chemical Industry
Nutritional quality of red shrimp, Aristeus antennatus (Risso), pink shrimp, Parapenaeus longirostris (Lucas), and Norway lobster, Nephrops norvegicus (Linnaeus)
Authors: Rosa Rui , Nunes Maria L
Published: December 2003

The proximate composition, amino acid and fatty acid profiles, lipid classes and cholesterol and glycogen contents were determined in the edible part of red shrimp, Aristeus antennatus (Risso), pink shrimp, Parapenaeus longirostris (Lucas), and Norway lobster, Nephrops norvegicus (Linnaeus), in two distinct periods of the year. The proximate composition did not vary significantly between species or between periods of sampling. Significant differences in glycogen content were obtained between winter and summer; the lowest values were attained in winter (1.2, 1.1 and 1.0% wet weight for red shrimp, pink shrimp and Norway lobster respectively). With the exception of Norway lobster, an opposite trend was obtained for cholesterol content, ie lower values in summer (60.8 and 57.8 mg per 100 g wet weight for red shrimp and pink shrimp respectively). The major essential amino acids (EAA) were arginine, lysine and leucine and the limiting amino acid was methionine in all three crustacean species. The most important non‐essential amino acids (NEAA) were glutamic acid, aspartic acid, proline and glycine. In respect to lipid classes, phospholipids and free cholesterol predominated. The major fatty acids were 16:0, 18:1n‐9, 20:5n‐3 and 22:6n‐3. The polyunsaturated fraction was dominant (42.1–48.4%), followed by the monounsaturated (26.3–34.6%) and saturated (22.9–27.4%) fatty acids. In conclusion, the nutritional quality of these shellfish species is similar, they are valuable protein and lipid sources for the human diet and are adequate elements of the traditional Portuguese diet. Copyright © 2003 Society of Chemical Industry
Fungal metabolism of butter and shea oils by Penicillium roquefortii in solid state cultures
Authors: Liu Qin‐Tao
Published: December 2003

Monoacylglycerols (monoglycerides, MAGs) were produced from butter oil and shea stearin fraction (shea oil) by two strains of Penicillium roquefortii, FRR 2456 (isolated from a spoilt melon) and Wisbey PJ (a commercial dairy strain), at pH 7.0 at 10 and 25 °C. The system was designed as a model of cheese using modified Czapek medium in solid state cultures. Shea oil with its unique fatty acid profile (stearic, oleic and palmitic acids) was used for comparison with butter oil. Yields of MAGs, which ranged from 3 to 14 g kg−1 oil, were higher with butter than with shea oil and higher when the spoilage strain FRR 2456 was used. Monoacylglycerols produced by mycelium‐bound lipases from both fungal strains were mainly sn‐1(3) or α isomers (60–70 mol%). Monopalmitin was the major MAG produced from both butter and shea oils. The production and use of MAGs alone or in combination with free fatty acids (FFAs) as food preservatives are discussed. It is implied that sn‐1(3) MAGs together with free fatty acids may be part of a natural antimicrobial system in relatively high‐pH foods such as blue mould‐ripened cheese where growth of foodborne pathogens such as Listeria monocytogenes can be a problem. Copyright © 2003 Society of Chemical Industry
Studies on the Synthesis and Properties of Temperature Responsive and Biodegradable Hydrogels
Authors: Sun Li‐Fang , Zhuo Ren‐Xi , Liu Zhi‐Lan
Published: December 2003

Novel linear poly(NIPA‐co‐CL) copolymers have been synthesized by radical copolymerization of N‐isopropylacrylamide (NIPA) and 2‐methylene‐1,3‐dioxepane (MDO). The structure of copolymers was confirmed by 1H NMR and IR spectroscopy. Cross‐linked poly(NIPA‐co‐CL) hydrogels have also been prepared in toluene using N,N′‐methylenebisacrylamide as cross‐linking agent. The hydrogels thus obtained exhibit good temperature response and are biodegradable in the presence of proteinase K.

Temperature influence on the enzymatic degradation by proteinase K of poly(NIPA‐co‐CL) hydrogel (G‐60).

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Temperature influence on the enzymatic degradation by proteinase K of poly(NIPA‐co‐CL) hydrogel (G‐60).
A Novel Gelatin–Carbon Nanotubes Hybrid Hydrogel
Authors: Li He , Wang Di Qiang , Chen Hua Lin , Liu Bai Ling , Gao Li Zhen
Published: December 2003

This letter focuses on the first result of the preparation and the swelling behavior of a novel hybrid gelatin hydrogel with carbon nanotubes. A novel hybrid gelatin hydrogel with carbon nanotubes was synthesized by a physical mixing method. The structure of the novel hydrogel obtained was characterized by SEM. Besides, the swelling behavior of the synthesized hydrogel was measured at two different temperatures. The results indicate that carbon nanotubes added could maintain the stability of the hybrid hydrogel without cross‐linking at 37 °C. This suggests that the hybrid gelatin hydrogel with carbon nanotubes could be used in biomedical field. Besides, its application in protein separation is discussed.

SEM image of the gelatin‐MWNTs hybrid gel at 10 000 × magnification.

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SEM image of the gelatin‐MWNTs hybrid gel at 10 000 × magnification.
A Wide‐Bandgap Semiconducting Polymer for Ultraviolet and Blue Light Emitting Diodes
Authors: Lu Ping , Zhang Haiquan , Shen Fangzhong , Yang Bing , Li Di , Ma Yuguang , Chen Xinfang , Li Jinghong , Tamai Naoto
Published: December 2003

A novel wide‐bandgap conjugated polymer (PDHFSCHD) consisting of alternating dihexylfluorene and rigidly twisted biphenyl units has been synthesized. The new fluorene‐based copolymer composed of rigid twisting segments in the main‐chain exhibits an optical bandgap of as high as 3.26 eV, and a highly efficient ultraviolet emission with peaks at 368 nm and 386 nm. An electroluminescence device from PDHFSCHD neat film as an active layer shows UV emission which peaks at 395 nm with a turn on voltage below 8 V. By optimizing the device conditions, a peak EL quantum efficiency of 0.054% and brightness of 10 cd · m−2 was obtained. Furthermore, blending a poly(dihexylfluorene) in the PDHFSCHD host gave pure blue emission peaking at 417 nm and 440 nm without long wavelength emission from aggregated species. Efficient energy transfer from PDHFSCHD to PDHF was demonstrated in these blended systems. Depressed chain‐aggregation of PDHF in the PDHFSCHD host can correspond to pure blue emission behaviors.

The structure of the copolymer PDHFSCHD.

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The structure of the copolymer PDHFSCHD.
Synthesis of Diene‐Functionalized Macromonomers via Functionalization with Hexa‐1,3,5‐triene
Authors: Quirk Roderic P. , Gomochak Deanna L. , Bhatia Rajeev S. , Wesdemiotis Chrys , Arnould Mark A. , Wollyung Kathleen
Published: December 2003

The reaction of poly(styryl)lithium (PSLi) with hexa‐1,3,5‐triene (HXT) was studied as a route to diene‐functionalized macromonomers. When PSLi was reacted with 1.5 molar equivalents of HXT for 2.5 h at −10 °C in toluene, it was found that the diene‐functionalized macromonomer was obtained in high yield; however, oligomerization of the HXT was observed by matrix‐assisted laser absorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Oligomerization was eliminated by running the reaction with only 1.2 molar equivalents of HXT to PSLi and allowing the reaction to run for 15 min at −10 °C in toluene. The resulting polymer exhibited high diene chain‐end functionality and no oligomerization was observed by MALDI‐TOF MS. 13C NMR spectroscopy and the attached‐proton test (APT), along with calculated chemical shifts, showed the presence of both the 1,2‐ and 1,4‐addition chain‐end structures. Further analysis by the reaction of the functional polymer with maleic anhydride indicated that 18 wt.‐% of the product was unreactive, either because of a 1,4‐addition chain‐end structure or a nonfunctional polymer. The structure of the maleic anhydride‐modified polymer was determined by MALDI‐TOF MS and 13C NMR spectroscopy. Preliminary work on the reactivity of the diene‐functionalized macromonomers was performed by the addition of a large excess of PSLi to a solution of macromonomer followed by characterization by size‐exclusion chromatography (SEC).

The formation of hexa‐1,3,5‐triene‐functionalized polystyrenes and their reaction with maleic anhydride.

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The formation of hexa‐1,3,5‐triene‐functionalized polystyrenes and their reaction with maleic anhydride.
Pyrromethene 567 Dye as Visible Light Photoinitiator for Free Radical Polymerization
Authors: García O. , Costela A. , García‐Moreno I. , Sastre R.
Published: December 2003

In the present work we report on the photochemistry and photopolymerization activity of a new bimolecular photoinitiator system, which exhibits maximum sensitivity at 518 nm, consists of a sensitizer dye, pyrromethene 567 (PM567), and a radical generating reagent 3,3′,4,4′‐tetra(tert‐butylperoxycarbonyl)benzophenone (BTTB). The photosensitization of BTTB through the excitation of PM567 induces high polymerization rates, while different experiences have revealed that PM567 or BTTB, separately, are unable of initiating the polymerization of 2‐hydroxyethyl methacrylate (HEMA) over extensive periods of time at 40 °C, either in the dark or under irradiation. The polymerization efficiency of this photoinitiator system, PM567/BTTB, was analyzed following the bulk polymerization kinetics of monomer HEMA by differential scanning photo‐calorimetry. Photopolymerization rates and quantum yields were observed under isothermal conditions (40 °C) for continuous illumination polymerizations (at 518 nm) at different incident light intensities and different BTTB concentrations.

Scheme of the photosensitization process of the bimolecular photoinitiator system of PM567/BTTB.

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Scheme of the photosensitization process of the bimolecular photoinitiator system of PM567/BTTB.
Preparation of Monodisperse Crosslinked Organic‐Inorganic Hybrid Copolymer Particles by Dispersion Polymerization
Authors: Jun Jung‐Bae , Hong Jae‐Keun , Park Jin‐Gyu , Suh Kyung‐Do
Published: December 2003

This study presents a new method for producing monodisperse crosslinked organic‐inorganic hybrid polymer particles in micron‐size by using simple dispersion polymerization. Firstly, highly monodisperse hybrid copolymer particles were prepared by conventional dispersion polymerization of styrene and 3‐(trimethoxysilyl)propyl methacrylate (TMSPM) in a methanol/water medium. It was very interesting to find that slightly crosslinked hybrid polymer particles were formed by this simple dispersion polymerization due to a partial condensation reaction between the adjacent silanol groups of the TMSPM during the polymerization. Secondly, for the hydrolytic condensation of the remaining trimethoxysilyl groups, post treatment by sol‐gel process was carried out to form an inorganic siloxane network, which provides the particle with high crosslinking density. In the proper conditions, monodisperse crosslinked particles could be produced in high TMSPM concentrations, up to 20 wt.‐%. In addition, the size monodispersity of the hybrid polymer particles was maintained after the sol‐gel process. Crosslinking with inorganic networks formed by the sol‐gel process was confirmed by a thermal analysis and a 29Si NMR spectroscopy.

Synthesis of crosslinked organic‐inorganic hybrid polymer particles by dispersion copolymerization and post sol‐gel process.

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Synthesis of crosslinked organic‐inorganic hybrid polymer particles by dispersion copolymerization and post sol‐gel process.
Combustion Behaviour of Epoxide Based Nanocomposites with Ammonium and Phosphonium Bentonites
Authors: Hartwig Andreas , Pütz Dirk , Schartel Bernhard , Bartholmai Matthias , Wendschuh‐Josties Michael
Published: December 2003

The influence of different organobentonites on the decomposition and the combustion behaviour of an epoxy resin were examined. The epoxy resin is a cationically polymerised cycloaliphatic epoxy resin flexibilised with poly(tetrahydrofuran) (PTHF), with hydroxyl endgroups. The bentonite was modified with either an ammonium or a phosphonium salt. The thermal decomposition of the PTHF induced by the initiator, used for the cationic polymerisation, did neither take place for the nanocomposite based on the ammonium bentonite nor for that based on the phosphonium bentonite. This improved decomposition characteristic lead to a larger time to ignition for both kinds of nanocomposites compared to the not modified polymer, which is not the case for other polymer/clay nanocomposites described in the literature. The fire behaviour was investigated using limiting oxygen index (LOI), a horizontal burner test and a cone calorimeter. The forced flaming conditions in the cone calorimeter were varied using different external heat fluxes between 30 and 70 kW · m−2. The fire behaviour of the nanocomposites was improved in comparison to the polymer, and phosphonium bentonite was superior to ammonium bentonite. The main mechanism is a barrier formation resulting in a reduction of the fire growth rate, which was more pronounced in the case of high external heat fluxes.

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