bluuebunny/crossref_metadata_2025 huggingface dataset:
Electroencephalography (EEG): Inverse Problems
Authors: He Bin , Hori Junichi , Babiloni Fabio
Published: April 2006

In this chapter, we review the principles and state‐of‐the‐art of EEG inverse problems and source imaging. Both the basics and the concepts of the inverse problem and the latest development in EEG inverse are covered.
Multimodal Presentation of Biomedical Data
Authors: Obrenović Željko , Starčević Dušan , Jovanov Emil
Published: April 2006

Insights into multidimensional phenomena, characteristic for biomedical applications, necessitates human‐computer interfaces beyond standard graphical user interfaces (GUIs). Information overload in one sense, such as multiple dynamically changing windows in GUIs, may cause fatigue and reduced attention. Multimodal presentations use different sensory modalities in addition to visual presentation, such as audio and tactile feedback, to further engage human perceptual and cognitive skills. Multimodal presentation is a promising new direction toward increased perceptual bandwidth of human‐computer interaction. Moreover, multimodal communication is natural feature of human communication. Therefore, most users prefer multimodal computer interaction. However, design of multimodal systems is a complex issue, and system designers must keep in mind that the nature of human perception and sensory interactions could also create false perceptions. In this chapter, we present a survey of the main presentation modalities and their characteristics, outline system design using available tools and platforms, and introduce examples of multimodal biomedical applications.
Scalable production of adeno‐associated virus type 2 vectors via suspension transfection
Authors: Park Joon Young , Lim Byung‐Pil , Lee Kyuhyun , Kim Young‐Gun , Jo Eui‐Cheol
Published: April 2006

Vectors derived from adeno‐associated virus type 2 (AAV2) are promising gene delivery vehicles, but it is still challenging to get the large number of recombinant adeno‐associated virus (rAAV) particles required for large animal and clinical studies. Current transfection technology requires adherent cultures of HEK 293 cells that can only be expanded by preparing multiple culture plates. A single large‐scale suspension culture could replace these multiple culture preparations, but there is currently no effective co‐transfection scheme for generating rAAV from cells in suspension culture. Here, we weaned HEK 293 cells to suspension culture using hydrogel‐coated six‐well culture plates and established an efficient transfection strategy suitable for these cells. Then the cultures were gradually scaled up. We used linear polyethylenimine (PEI) to mediate transfection and obtained high transfection efficiencies ranging from 54% to 99%, thereby allowing efficient generation of rAAV vectors. Up to 1013 rAAV particles and, more importantly, up to 1011 infectious particles were generated from a 2‐L bioreactor culture. The suspension‐transfection strategy of this study facilitates the homogeneous preparation of rAAV at a large scale, and holds further potential as the basis for establishing a manufacturing process in a larger bioreactor. © 2006 Wiley Periodicals, Inc.
‘Pre‐discursive’ racism
Authors: Hook Derek
Published: April 2006

This paper makes the case that discourse analytic approaches in social psychology are not adequate to the task of apprehending racism in its bodily, affective and pre‐symbolic dimensions. We are hence faced with a dilemma: if discursive psychology is inadequate when it comes to theorizing ‘pre‐discursive’ forms of racism, then any attempts to develop an anti‐racist strategy from such a basis will presumably exhibit the same limitations. Suggesting a rapprochement of discursive and psychoanalytic modes of analysis, I argue that Kristeva's theory of abjection provides a means of understanding racism as both historically/socially constructed and as existing at powerfully embodied, visceral and subliminal dimensions of subjectivity. Kristeva's theory of abjection provides us with an account of a ‘pre‐discursive’ (that is, a bodily, affective, pre‐symbolic) racism, a form of racism that ‘comes before words’, and that is routed through the logics of the body and its anxieties of distinction, separation and survival. This theory enables us, moreover, to join together the expulsive reactions of a racism of the body to both the personal racism of the ego and the broader discursive racisms of the prevailing social order. Moreover, it directs our attention to the fact that discourses of racism are always locked into a relationship with ‘pre‐discursive’ processes which condition and augment every discursive action, which escape the codifications of discourse and which drive the urgency of its attempts at containment. Copyright © 2006 John Wiley & Sons, Ltd.
‘How can we help when she won't tell us what's wrong?’ Professionals working with South Asian women who have experienced sexual abuse
Authors: Reavey Paula , Ahmed Bipasha , Majumdar Anamika
Published: April 2006

In this paper, we explore some of the issues facing professionals in the UK currently involved in providing services for South Asian women who have experienced sexual abuse. The study describes part of a wider Economic and Social Research Council funded project, based upon interviews and focus groups with both professionals and women survivors of sexual abuse. Drawing on semi‐structured interviews and two focus groups with 37 professionals including psychological therapists, refuge and project workers, from a range of organisations, our aim in this paper is to provide a discursive analysis of some of the key dilemmas faced by professionals working with sexual abuse in South Asian communities by exploring two central interpretive repertoires: ‘culture not self’ and ‘symptom talk as solution’. The analysis indicates that professionals face a series of dilemmas when working with South Asian women survivors. They highlight the tension between individualised models of personhood in many psychological therapies and the challenge to these by South Asian communities who hold a more relational view of the person. One of the strategies used by professionals to work with the tensions between ‘culture’ and the ‘reality’ of the survivor's pain was the translation of women's distress into symptoms of mental disorder. However, the consequences of this intervention raised some serious issues, including further pathologisation and stigma. The implications of these findings will be discussed in terms of how to understand the experiences of South Asian women from a more socially grounded perspective and to explore the issues they face in accessing and receiving appropriate services to deal with the aftermath of sexually abusive experiences. Copyright © 2006 John Wiley & Sons, Ltd.
Adaptive and Predictive Control of Liquid‐Liquid Extractors Using Neural‐Based Instantaneous Linearization Technique
Authors: Mjalli F. S.
Published: April 2006

Nonlinearity of the extraction process is addressed via the application of instantaneous linearization to control the extract and raffinate concentrations. Two feed‐forward neural networks with delayed inputs and outputs were trained and validated to capture the dynamics of the extraction process. These nonlinear models were then adopted in an instantaneous linearization algorithm into two control algorithms. The self‐tuning adaptive control strategy was compared to an approximate model predictive control in terms of set point tracking capability, efficiency and stability. For the case of large, abrupt set point changes, the performance of the self‐tuning algorithm was poor, especially for the raffinate control. The approximate model predictive control strategy was superior to the self‐tuning control in terms of its ability to force the output to following the set point trajectory efficiently with smooth controller moves.
Comparison of Energy Efficiency of Various Ultrasonic Devices in Aquasonochemical Reactions
Authors: Wu Z.‐L. , Lifka J. , Ondruschka B.
Published: April 2006

For economic reasons, reaction rate and energy efficiency of ultrasonic devices need to be higher. In this investigation, it was found that the 850 kHz ultrasonic device achieves a higher energy efficiency and a higher sonochemical reaction rate than the 24 or 30 kHz device during the oxidation of KI or the degradation of benzene in aqueous solutions. Moreover, lower power intensity or higher power density is generally favorable to the oxidation of KI. For benzene degradation, however, energy efficiency is enhanced with the increase in power intensity and density at lower input power and decreases with the increase in power intensity and density at higher input power. In addition, energy efficiency can also be diminished by changing fluid motion, for example, shortening the distance between the tip of the ultrasonic horn and the reactor bottom, and stirring during sonication.
An Electrochemical Model of a Solid Oxide Steam Electrolyzer for Hydrogen Production
Authors: Ni M. , Leung M. K. H. , Leung D. Y. C.
Published: April 2006

An electrochemical model was developed to simulate the J–V characteristics of a solid oxide steam electrolyzer (SOSE) used for hydrogen production. Activation, concentration, and ohmic overpotentials were considered as the main factors for voltage loss. The Butler‐Volmer equation, Fick's model, and Ohm's law were applied to determine the overpotentials of a SOSE cell. The simulation results were compared with experimental data from the literature and good agreement was obtained. Additionally, parametric modeling analyses were conducted to study how the operating temperature and gas composition affected the electrical characteristics. It was found that the voltage loss could be reduced by increasing the operating temperature and steam molar fraction. It was also observed that an anode‐supported SOSE cell exhibited a higher hydrogen production efficiency than electrolyte‐supported and cathode‐supported cells. The electrochemical model can be used to perform further analysis in order to further understand the principles of SOSE hydrogen production, and to optimize SOSE cell and system designs.
Study of Single Phase Flow Heat Transfer and Friction Pressure Drop in a Spiral Internally Ribbed Tube
Authors: Cheng L. , Chen T.
Published: April 2006

The experimental results of single‐phase flow heat transfer and pressure drop experiments in the turbulent flow regime in a spirally ribbed tube and a smooth tube are presented in this paper. The ribbed tube has an outside diameter of 22 mm and an inside diameter of 11 mm (an equivalent inside diameter of 11.6 mm) and the smooth tube has an outside diameter of 19 mm and an inside diameter of 15 mm. Both tubes were uniformly heated by passing an electrical current along the tubes with a heated length of 2500 mm. The working fluids are water and kerosene, respectively. The experimental Reynolds number is in the range of 104–5 · 104 for water and is in the range of 104–2.2 · 104 for kerosene. The experimental results of the ribbed tube are compared with those of the smooth tube. The heat transfer coefficients of the ribbed tube are 1.2–1.6 fold greater than those in the smooth tube and the pressure drop in the ribbed tube is also increased by a factor of 1.4–1.7 as compared with those in the smooth tube for water. The corresponding values for kerosene are 2–2.7 and 1.5–2, respectively. The heat‐transfer enhancement characteristics of the ribbed tube are assessed. This tube is especially suitable for augmenting single‐phase flow heat transfer of kerosene. Correlations for the heat transfer and the pressure drop for the spirally ribbed tube are proposed, according to the experimental data.
A Direct Electrochemical Route from Ilmenite to Hydrogen‐Storage Ferrotitanium Alloys
Authors: Ma Meng , Wang Dihua , Hu Xiaohong , Jin Xianbo , Chen George Z.
Published: April 2006

An unrecognised but predictable need for a hydrogen‐supported society is tens or even hundreds of million tonnes of hydrogen‐storage materials, and thus challenges existing technologies in terms of resource and economical realities. Ilmenite is an abundant mineral, and ferrotitanium alloys are among the earliest known hydrogen‐storage materials. At present, industrial production of ferrotitanium alloys goes through separate extraction of individual metals, followed by a multistep arc‐melting process. In particular, the extraction of titanium from ilmenite is highly energy intensive and tedious, accounting for titanium's high market price and restricted uses. This article reports the electrochemical synthesis of various ferrotitanium alloy powders directly from solid ilmenite in molten calcium chloride. More importantly, it demonstrates, for the first time, that such produced alloy powders can be used without further treatment for hydrogen storage and perform comparably with or better than similar products by means of other methods, but cost just a fraction.
Bis(2‐amino alcohol‐κN)dicarboxylatoplatinum(II) Complexes – Elegant Synthesis via Ring‐Opening of Bis(2‐amino alcoholato‐κ2N,O)platinum(II) Species with Dicarboxylic Acids
Authors: Meelich Kristof , Galanski Mathea Sophia , Arion Vladimir B. , Keppler Bernhard K.
Published: April 2006

Synthesis and purification of bis(2‐amino alcohol‐κN)dicarboxylatoplatinum(II) complexes is problematic because of the use of light‐sensitive silver(I) salts and the competing ring‐closing side‐reactions, especially after release of the chloro‐ or iodo ligands of the dihalogeno starting platinum(II) species. A novel synthetic procedure, namely selective synthesis of doubly ring‐closed bis(2‐amino alcoholato‐κ2N,O)platinum(II) compounds as the purification step and subsequent coordination of dicarboxylates in the absence of silver(I) via a ring‐opening reaction, yielded a series of new complexes, which were characterized by elemental analysis, NMR spectroscopy, and X‐ray crystallography. Exemplarily, the ring‐opening of bis(2‐aminoethanolato‐κ2N,O)platinum(II) was performed in the NMR tube by means of oxalic acid and investigated by 1H and 195Pt NMR spectroscopy. The reaction was found to be highly efficient: within 3 h complete transformation to the dicarboxylatoplatinum(II) complex was observed. Contrary, when sodium oxalate was used, no reaction could be detected at all during a period of one day.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Management of environmental crop conditions to produce useful sunflower oil components
Authors: Roche Jane , Bouniols Andrée , Mouloungui Zéphirin , Barranco Thomas , Cerny Muriel
Published: April 2006

The objective of this study was to investigate the impact of water availability and temperature after flowering on oil, major fatty acid and sterol contents in seeds of standard and oleic sunflower genotypes, under managed and controlled field conditions. When water deficit was effective from the beginning to the end of anthesis, it modified the fatty acid composition of standard hybrids. When water was supplied, a major enhancement of oleic acid content was associated with a concomitant reduction of linoleic acid content and a decrease in saturated fatty acid contents. Higher temperatures increased the oleic acid content in seeds of standard hybrids. Oil content was enhanced under colder temperature and irrigation. The content of minor oil components, phytosterols, was also enhanced when seed development occurred under high temperature and severe water stress. As a whole, the data showed that combining water management, sowing date and choice of genotype may orientate the biosynthesis of seed components and thus generate seed composition variability suitable for industrial purposes.
Sodium Bis(trimethylsilyl)amide in the Oxidative Conversion of Aldehydes to Nitriles
Authors: Ru Hwu Jih , Fuh Wong Fung
Published: April 2006

The feasibility of the Me3Si species acting as a nucleofuge was investigated in compounds containing the NSiMe3 moiety. Treatment of various aromatic aldehydes with 2.2 equiv. of NaN(SiMe3)2 at 185 °C in a sealed tube produced the corresponding nitriles in high yields (81–98 %). In these reactions, NaN(SiMe3)2 acted as an oxidizing agent. Results from control experiments indicate that the Me3Si unit can depart efficiently from the NSiMe3 moiety of N‐silylimine intermediates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Design considerations for low antenna correlation and mutual coupling reduction in multi antenna terminals
Authors: Thaysen Jesper , Jakobsen Kaj B.
Published: April 2006

The influence of mutual coupling on the envelope correlation between two identical planar inverted F‐antennas (PIFA) are investigated. The capacity of a multiple‐input multiple‐output (MIMO) antenna system strongly depends on the correlation between the antennas. By placing two antennas in a fixed area, it is found that the envelope correlation could be halved simply by proper mutual orientation. The set‐ups that maximise the distances between the open ends of the PIFAs yield the lowest mutual coupling as well as the lowest envelope correlations. It is found that the envelope correlation is 0.8 when the PIFAs are oriented in parallel. The envelope correlation can be decreased to 0.4 by rotating one of the PIFAs by 180 degrees. Copyright © 2006 AEIT
Acquisition performance for NDA symbol‐timing recovery with simple adaptive first‐order loops
Authors: Gappmair Wilfried , Flohberger Markus , Koudelka Otto
Published: April 2006

Powerful feedforward estimators for symbol‐timing recovery are more or less mandatory for efficient acquisition in time‐division multiple access (TDMA) modems. However, in many cases, feedback solutions are much less complex from the computational point of view. The latter can be an attractive alternative for continuous transmission of data like DVB, where rapid acquisition is not so important as with TDMA. In order to describe analytically the acquisition performance of first‐order loops with Gardner detectors, it is shown that the related analog model can be successfully applied. In the sequel, this approach is used to demonstrate that the acquisition process may be accelerated significantly via simple adaptive loop filters. Copyright © 2006 AEIT
A small monetary system for the euro area based on German data
Authors: Brüggemann Ralf , Lütkepohl Helmut
Published: April 2006

Previous euro area money demand studies have used aggregated national time series data from the countries participating in the European Monetary Union (EMU). However, aggregation may be problematic because macroeconomic convergence processes have taken place in the countries of interest. Therefore, in this study, quarterly German data until 1998 are combined with data from the euro area from 1999 until 2002 and these series are used for fitting a small vector error correction model for the monetary sector of the EMU. A stable long‐run money demand relation is found for the full sample period. Moreover, impulse responses do not change much when the sample period is extended by the EMU period provided the break in the extended data series is captured by a simple dummy variable. Copyright © 2006 John Wiley & Sons, Ltd.
Long‐term cryopreservation of dental pulp stem cells (SBP‐DPSCs) and their differentiated osteoblasts: A cell source for tissue repair
Authors: Papaccio Gianpaolo , Graziano Antonio , d'Aquino Riccardo , Graziano Maria Francesca , Pirozzi Giuseppe , Menditti Dardo , De Rosa Alfredo , Carinci Francesco , Laino Gregorio
Published: April 2006

It is not known whether cells derived from stem cells retain their differentiation and morpho‐functional properties after long‐term cryopreservation. This information is of importance to evaluate their potential for long‐term storage with a view to subsequent use in therapy. Here, we describe the morpho‐functional properties of dental pulp stem cells (SBP‐DPSCs), and of their differentiated osteoblasts, recovered after long‐term cryopreservation. After storage for 2 years, we found that stem cells are still capable of differentiation, and that their differentiated cytotypes proliferate and produce woven bone tissue. In addition, cells still express all their respective surface antigens, confirming cellular integrity. In particular, SBP‐DPSCs differentiated into pre‐osteoblasts, showing diffuse positivity for ALP, BAP, RUNX‐2, and calcein. Recovered osteoblasts expressed bone‐specific markers and were easily recognizable ultrastructurally, with no alterations observed at this level. In addition, after in vivo transplantation, woven bone converted into a 3D lamellar bone type. Therefore, dental pulp stem cells and their osteoblast‐derived cells can be long‐term cryopreserved and may prove to be attractive for clinical applications. J. Cell. Physiol. 208: 319–325, 2006. © 2006 Wiley‐Liss, Inc.
Unimolecular Amphiphilic Nanocontainers Based on Dendronized Linear Polymers
Authors: Zhang Zhong‐Biao , Teng Yu‐Han , Freas William , Mohanty Dillip K.
Published: April 2006

Summary: Linear polymeric core, polyethylenimine (PEI), is successfully dendronized divergently using different‐generation polyamidoamine (PAMAM)‐type dendrons. The formed dendronized polymers are further end‐capped using long alkyl acrylate, hexyl acrylate, to give macromolecular amphiphiles, which perform as unimolecular nanocontainers, capable of encapsulating water‐soluble dye in their interiors. The encapsulation properties are found to be generation‐dependent, in which, at higher generations of nanocontainers, the cavity becomes more localized, due to dense packing of the dendrons at their termini.

Dendronization of a linear polymeric core followed by capping with hydrophobic arms.

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Dendronization of a linear polymeric core followed by capping with hydrophobic arms.
Salt‐Induced Depression of Lower Critical Solution Temperature in a Surface‐Grafted Neutral Thermoresponsive Polymer
Authors: Jhon Young K. , Bhat Rajendra R. , Jeong Changwoo , Rojas Orlando J. , Szleifer Igal , Genzer Jan
Published: April 2006

Summary: Quartz crystal microbalance with dissipation monitoring (QCM‐D) is employed to determine the effect of salt on the volume phase transition of thermoresponsive polymer brushes. Changes in mass and viscoelasticity of poly(N‐isopropylacrylamide) (PNIPAM) layers grafted from a QCM‐D crystal are measured as a function of temperature, upon contact with aqueous solutions of varying salt concentrations. The phase‐transition temperature of PNIPAM brushes, TC,graft, quantified from the QCM‐D measurements is found to decrease as the concentration of salt is increased. This phenomenon is explained by the tendency of salt ions to affect the structure of water molecules (Hofmeister effect). However, in contrast to the linear decrease in phase‐transition temperature upon increasing salt concentration observed for free PNIPAM, the trend in TC,graft for PNIPAM brushes is distinctively non‐linear.

Schematic representation of the effect of salt concentration on the phase transition behavior of thermoresponsive polymer brushes.

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Schematic representation of the effect of salt concentration on the phase transition behavior of thermoresponsive polymer brushes.
Novel Water‐Soluble Poly(m‐benzamide)s: Precision Synthesis and Thermosensitivity in Aqueous Solution
Authors: Sugi Ryuji , Ohishi Tomoyuki , Yokoyama Akihiro , Yokozawa Tsutomu
Published: April 2006

Summary: Chain‐growth polycondensations of 3‐aminobenzoic acid methyl esters 1a and 1b, bearing a tri‐ or tetra(ethylene glycol) methyl ether unit on the amino group, respectively, were carried out with lithium hexamethyldisilazide (LiHMDS) as a base and phenyl 4‐methylbenzoate (2) as an initiator in THF at 0 °C. The poly(m‐benzamide)s obtained in the presence of N,N,N′,N′‐tetramethylethylenediamine (TMEDA) possessed narrow molecular weight distributions ($\overline M _{\rm w} /\overline M _{\rm n}$ < 1.2) with molecular weights that were determined by the feed ratios of [1]0/[2]0. Poly1a and poly1b were each soluble in water and exhibited a lower critical solution temperature (LCST) in water. Furthermore, the phase separation in water depended on the length of the oligo(ethylene glycol) side chain and on the molecular weight and molecular weight distribution of poly1.

Thermally sensitive water‐soluble poly(m‐benzamide)s.

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Thermally sensitive water‐soluble poly(m‐benzamide)s.
High Pressure Induced Coil‐Globule Transitions of Smart Polymers
Authors: Kirpach A. , Adolf D.
Published: April 2006

Summary: In current work time‐resolved optical spectroscopy (TROS) has been used to study coil‐globule transitions monitored by the local segmental dynamics of anthracene labeled poly (N‐isopropymethacrylamide), PNIPMAM as a function of pressure (0.1 MPa–200 MPa) over a temperature range of 283 K to 333 K. The positions of temperature‐induced transition were observed to be independent on molecular weight of polymer at low pressures. The positions of pressure‐induced transition were observed to be dependent on molecular weight of polymer at temperatures below LCST at atmospheric pressure. Double globule‐coil‐globule transition was observed to occur with pressure increasing at temperatures nearly above LCST. All these results along with values of intrinsic viscosity evaluated from values of correlation times measured for globules formed at different pressure/temperature conditions suggest the different mechanisms of compactisation governed by pressure and temperature and, correspondently, the different types of final structures. At low pressures with temperature increasing the compact, well‐packed globules are forming via initial interactions between neighboring parts of polymer chain and further collapse. Relatively loosened particles are forming with pressurizing at low temperatures. Interaction between remote along the chain units takes part from the first stage of globule formation. And finally, rather solvated and irregularly twisted particles are forming at high pressure and high temperatures, i.e. at conditions, when both processes are involved.
Characterization of EO‐PO Block Copolymers by Liquid Chromatography Under Critical Conditions
Authors: Trathnigg Bernd , Gorbunov Alexei
Published: April 2006

Summary:Block copolymers of ethylene oxide (EO) and propylene oxide (PO) are characterized by liquid chromatography under critical conditions (LCCC) for EO. At the critical adsorption point (CAP) for one structural unit, the non‐critical block can elute in size exclusion (SEC) or adsorption (LAC) mode. Depending on the molar mass and architecture of the polymers, different strategies are applied. For samples with a higher molar mass, the SEC separation is the method of choice, while lower molar masses also allow a LAC separation. Examples for both situations are given, which show, that these approaches yield different information. In the SEC mode, homopolymers and diblocks can be separated from the triblocks. In LAC mode, a baseline resolution of individual oligomers can be achieved, in which homopolymers, diblocks and triblocks with the same number of repeat units of the non‐critical block have the same elution volume.
The Swelling Behavior of Charged Hydrogels
Authors: Mann Bernward A. , Kremer Kurt , Holm Christian
Published: April 2006

Summary:We describe recent advances obtained in understanding the microscopic interplay of a charged hydrogel with its confined mobile counterions. Results of extensive computer simulations are compared to simple scaling descriptions for various solvent conditions. We will briefly discuss our simulation package ESPResSo which was used to perform the simulations. We demonstrate why simple scaling theories suffice to adequately describe the swelling behavior of these systems despite their enormous complexity. We will conclude with a presentation of ongoing results for polyelectrolyte networks under poor solvent conditions.
Projectile Attack of Surface Scattered Munitions: Prompt Shock Finite Element Models and Live Trials
Authors: Almond Robert J. , Murray Stephen G.
Published: April 2006

This paper reports on continued research addressing remote neutralization of surface scattered explosive ordnance (principally anti‐tank mines). A clearance method has been proposed using a low cost vehicle mounted gun system, capable of rapid remote neutralization to a range of 100 m. Explicit non‐linear dynamic finite element models have been produced using a Lee‐Tarver representation of the explosive fill. This paper verifies these models against previous experimental data and closed form theory. Initial work on the use of explosive and hypergolic payloads is discussed.
Detonation Velocities and Pressures, and their Relationships with Electric Spark Sensitivities for Nitramines
Authors: Wang Gui‐Xiang , Xiao He‐Ming , Xu Xiao‐Juan , Ju Xue‐Hai
Published: April 2006

The DFT‐B3LYP method, with basis set 6–31G*, is employed to optimize molecular geometries and electronic structures of eighteen nitramines. The averaged molar volume (V) and theoretical density (ρ) are estimated using the Monte‐Carlo method based on 0.001 electrons/bohr3 density space. Subsequently, the detonation velocity (D) and pressure (P) of the explosives are estimated by using the Kamlet‐Jacobs equation on the basis of the theoretical density and heat of formation (ΔfH), which is calculated using the PM3 method. The reliability of this theoretical method and results are tested by comparing the theoretical values of ρ and D with the experimental or referenced values. The theoretical values of D and P are compared with the experimental values of electric spark sensitivity (EES). It is found that for the compounds with metylenenitramine units (CH2N(NO2)) in their molecules (such as ORDX, AcAn and HMX) or with the better symmetrical cyclic nitramines but excluding metylenenitramine units (such as DNDC and TNAD), there is a excellent linear relationship between the square of detonation velocity (D2) or the logarithm of detonation pressure (lg P) and electric spark sensitivity (EES). This suggests that in the molecular design of energetic materials, such a theoretical approach can be used to predict their EES values, which have been proven to be difficult to predict quantitatively or to synthesize.
Investigation of an N‐Butyl‐N‐(2‐Nitroxyethyl)Nitramine (BuNENA) Process: Identification of Process Intermediates, By‐Products and Reaction Pathways
Authors: Sitzmann Michael E. , Trivedi Nirupam J. , Skahan Patrick B. , Kenar James A. , Nock Lori A. , Stern Alfred G.
Published: April 2006

A process for N‐butyl‐N‐(2‐nitroxyethyl)nitramine (BuNENA) was investigated: Step 1 involves N‐butyl‐ethanolamine addition to 98% HNO3 to form a salt mixture; Step 2 is addition of acetic anhydride/acetyl chloride catalyst to the salt mixture. A number of potential intermediates, by‐products, and decomposition products from this process were identified/synthesized for use as analytical standards. BuNENA process reaction pathways/mechanisms were elucidated, including the nature of the amine salt solution formed in Step 1. In addition, potential pathways that could account for by‐product formation were elaborated. A study of the consumption of acetyl nitrate in Step 2 was undertaken to prevent its build‐up.
Si‐oxide/Si and Si‐oxynitride/Si interfaces analysed by ultra‐low energy SIMS
Authors: Ćwil M. , Konarski P. , Bieniek T. , Beck R. B.
Published: April 2006

Depth profile analyses of silicon oxides and oxynitrides are compared using SIMS (Secondary Ion Mass Spectrometry) technique with ultra low energy of primary Ar+ ion beam. SiO2 (5–80 nm thick) layers on p‐Si 〈100〉 were formed by thermal heating of silicon wafers in oxygen flow. SiOx Ny (2–4 nm thick) layers on p‐Si 〈100〉 were obtained by nitrogen implantation followed by plasma oxidation process. The nitrogen implantation was performed with NH3 and N2 plasma sources in 350 °C. The influence of r.f. power, used during implantation on the oxynitride layer properties, was studied.

SIMS measurements were done using ultra‐low energy 880 eV Ar+ beam and quadrupole mass spectrometer. Quantitative atomic concentrations of nitrogen and oxygen were calculated basing on Si2N+, Si2O+ and Si2+ secondary ion currents. The obtained layers were also characterised by X‐ray Photoelectron Spectroscopy, ellipsometry and electrical tests. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Second harmonic generation in a molecular magnetic chain
Authors: Cavigli L. , Sessoli R. , Gurioli M. , Bogani L.
Published: April 2006

A setup for the determination of all the components of the second harmonic generation tensor in molecular materials is presented. It allows overcoming depletion problems, which one can expect to be common in molecular systems. A preliminary characterization of the nonlinear properties of the single chain magnet CoPhOMe is carried out. We observe a high second harmonic signal, comparable to that of urea, and show that the bulk contributions are dominant over the surface ones. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation of iron oxide nanoparticles from FeCl3 solid powder using microemulsions
Authors: Nassar Nashaat , Husein Maen
Published: April 2006

Nanoparticles of iron oxide were prepared by subjecting iron chloride powder to (w/o) microemulsions consisting of sodium bis(2‐ethylhexyl) sulfosuccinate (AOT), isooctane and water. FeCl3 was first dissolved in the water pools of the microemulsion, and then reacted with NaOH added as an aqueous solution to form iron oxide. The amount of NaOH solution was limited so that single microemulsion phase is obtained. This technique serves as an in‐situ nanoparticle preparation technique aimed at minimizing particle aggregation associated with particle transportation to required sites. In this study, the effects of AOT concentration and water to AOT mole ratio on the nanoparticle size were investigated. UV/Vis spectrophotometry and transmission electron microscopy (TEM) were used to measure the particle size distribution. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and characterization of polymer‐stabilized metal nanoparticles for sensor applications
Authors: Macanás J. , Farre M. , Muñoz M. , Alegret S. , Muraviev D. N.
Published: April 2006

Nanomaterial‐based sensing devices attract great attention of scientist and technologists due to the special properties of nano‐objects, such as for example, Metal Nanoclusters (MNC), which differ from those of the bulk materials. The further development of these devices requires novel approaches to stabilize MNC and therefore, to save their unique properties. The Solid‐Phase‐Incorporated‐Reagents (SPHINER) technique was used for in situ synthesis of Polymer‐Stabilized Metal Nanoclusters (PSMNC), which were used in the construction of new composite electrodes. The size of Pt‐PSMNC synthesized in polyvinyl chloride (PVC) and polysulfone stabilizing matrices was determined by Transmission Electron Microscopy (TEM) technique and appeared to be in majority of cases of 6–20 nm. The electrochemical characterization of PSMNC‐based amperometric sensors has demonstrated that inclusion of Pt‐MNC increases the electrical conductivity of the membrane and that the electrode performance strongly depends on both the type of polymeric matrix and the membrane preparation technique. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silica nanoparticle addition to control the calcium‐leaching in cement‐based materials
Authors: Gaitero J. J. , Sáez de Ibarra Y. , Erkizia E. , Campillo I.
Published: April 2006

The calcium leaching of the cement hydrated matrix is of vital importance for constructions like water containers, dams, bridges, etc which have to be in contact with water during their lifetime. The aim of this work is the study of the reduction of such a negative phenomenon by the addition of silica nanoparticles. Several characterisation techniques such as 29Si MAS NMR, X‐ray diffraction, mercury intrusion porosimetry and EDX‐microanalysis have been used to evaluate the effect of the nanoparticles in the cement matrix nanostructure and in their impact on the evolution of the Ca leaching throughout time. Subsequent analysis of the results indicates that silica nanoparticles can reduce the Ca‐leaching both decreasing the amount of portlandite in the matrix and controlling the degradation rate of the C–S–H gel. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and characterization of perylene nanoparticles
Authors: Latterini L. , Roscini C. , Carlotti B. , Aloisi G. G. , Elisei F.
Published: April 2006

Nanoparticles were prepared in different experimental conditions by a re‐precipitation method by use of perylene and polyvinylalcohol as active material and stabilizer, respectively. The excitation and emission spectral properties of dispersions in aqueous solutions of the various samples were recorded together with the fluorescence quantum yields and lifetimes (where detectable). The experimental results are consistent with the formation of excimer‐like states, responsible of the emission properties, in the nanoparticles. Confocal fluorescence and atomic force (AFM) microscopies were able to give information on the fluorescence properties and size distribution (most probable size of 3–5 nm) of the nanoparticles. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Composition and antibacterial activity of Abies balsamea essential oil
Authors: Pichette André , Larouche Pierre‐Luc , Lebrun Maxime , Legault Jean
Published: April 2006

The antibacterial activity of the essential oil of Abies balsamea (balsam fir) was evaluated against Escherichia coli and Staphylococcus aureus. The essential oil of A. balsamea was found to be inactive against E. coli (>100 µg/mL) and active against S. aureus, with an MIC of 56 µg/mL. The oil composition was analysed by GC‐MS and the antibacterial activity of each oil constituent was determined. The essential oil of A. balsamea is essentially constituted of monoterpenes (>96%) and some sesquiterpenes. β‐pinene (29.9%), δ‐3‐carene (19.6%) and α‐pinene (14.6%) were the major components. β‐pinene and δ‐3‐carene were found inactive against both bacteria strains. However, three constituents of the essential oil were active against S. aureus: α‐pinene, β‐caryophyllene (0.4%) and α‐humulene (0.2%) with MIC values of 13.6 µg/mL, 5.1 µg/mL and 2.6 µg/mL, respectively. Copyright © 2006 John Wiley & Sons, Ltd.
Plants and animals utilized as medicines in the Jaú National Park (JNP), Brazilian Amazon
Authors: Rodrigues Eliana
Published: April 2006

This article examines the therapeutic practices of the inhabitants of Jaú National Park (JNP), state of Amazonas, the most important feature of this region being its rich biodiversity associated with isolation in regard to conventional medical services. Seven months of field work were guided by methods of anthropology and botany. A total of 120 plants and 29 animals were utilized in 519 recorded uses comprising 81 therapeutic purposes. These were grouped under 15 categories of use, including: gastrointestinal disturbances, inflammatory processes, genitourinary disturbances, fever, mishaps with animals, dermatological problems, pain, osteomuscular problems and tropical diseases. Those who administer these medicines are local residents specializing in household remedies and other groups of healers such as rezadores – prayer‐maker; curadores – healers; parteiras – midwives; desmintidores – masseurs and médiuns – mediums. At least 10 of the 120 plants species cited in this study are also utilized by other inhabitants of the Amazon region and for the same uses; some of these plants had already been studied from a pharmacological point of view. Furthermore, another six plants cited by the JNP caboclos belonging to the categories pain and inflammatory processes, are under investigation by groups of researchers in two Brazilian federal universities. Copyright © 2006 John Wiley & Sons, Ltd.
In Vivo radioprotective effect of Panax ginseng C.A. Meyer and identification of active ginsenosides
Authors: Lee Hae June , Kim Se Ra , Kim Jong Choon , Kang Chang Mo , Lee Yun Sil , Jo Sung Kee , Kim Tae Hwan , Jang Jong Sik , Nah Seung Yeol , Kim Sung Ho
Published: April 2006

This study evaluated the effect of water extracts of Panax ginseng C.A. Meyer (PG), panaxadiol (PD), panaxatriol (PT), ginsenoside Rb1, Rb2, Rc, Rd, Re and Rg1 on jejunal crypt survival, endogenous spleen colony formation and apoptosis in jejunal crypt cells in gamma‐irradiated mice. Jejunal crypts were protected by pretreatment with PG, Rc and Rd. Administration of PG, PD, Rd and Re prior to irradiation resulted in an increase in the formation of endogenous spleen colonies. The frequency of radiation‐induced apoptosis in intestinal crypt cells was also reduced by pretreatment with PG, PD, Rb2, Rc, Rd, Re and Rg1. In experiments on the effects of the individual ginsenosides, the rank order of activity was Rc > Rd > Rg1 > Rb2 > Re > Rb1 on intestinal crypt survival assay, Re > Rb2 > Rd > Rg1 > Rb1 > Rc on the spleen colony formation assay, and Rg1 > Re > Rd > Rc > Rb2 > Rb1 on inhibiting the death of cells caused by apoptosis. The results indicated that Rc, Rd and Re may have a major radioprotective effect in mice irradiated with high and low doses of radiation. When the same experiments were performed using PD and PT, it was observed that most of the inhibitory effects came from PD rather than PT. Copyright © 2006 John Wiley & Sons, Ltd.
Antimicrobial activity of saponins from Medicago sp.: structure‐activity relationship
Authors: Avato Pinarosa , Bucci Rossella , Tava Aldo , Vitali Cesare , Rosato Antonio , Bialy Zbigniew , Jurzysta Marian
Published: April 2006

The antimicrobial activity of saponins from Medicago sativa, M. arborea and M. arabica against a selection of medically important yeasts, Gram‐positive and ‐negative bacteria was investigated. Structure‐activity growth inhibitory effects of related prosapogenins and sapogenins are also described. Increasing antibiotic activity was observed going from the saponin extracts to the sapogenin samples, suggesting that the sugar moiety is not important for the antimicrobial efficacy. Activity was especially high against Gram‐positive bacteria (Bacillus cereus, B. subtilis, Staphylococcus aureus and Enterococcus faecalis) with M. arabica being the species showing a broader spectrum of action. Discrete antifungal activity was also observed, mainly against Saccharomyces cerevisiae. The observed antimicrobial properties of M. sativa and M. arborea were related to the content of medicagenic acid, while hederagenin seems to contribute to the bioactivity of M. arabica total sapogenins. Copyright © 2006 John Wiley & Sons, Ltd.
Studies on hepatoprotective, antispasmodic and calcium antagonist activities of the aqueous‐methanol extract of Achillea millefolium
Authors: Yaeesh Sheikh , Jamal Qamar , Khan Arif‐ullah , Gilani Anwarul Hassan
Published: April 2006

The crude extract of Achillea millefolium (Am.Cr) was studied for its possible hepatoprotective effect against d‐galactosamine (d‐GalN) and lipopolysaccharide (LPS) induced hepatitis in mice and antispasmodic effect in isolated gut preparations to rationalize some of the folklore uses. Co‐administration of d‐GalN (700 mg/kg) and LPS (25 µg/kg) produced 100% mortality in mice. Pre‐treatment of animals with Am.Cr (300 mg/kg) reduced the mortality to 40%. Co‐administration of d‐GalN (700 mg/kg) and LPS (1 µg/kg) significantly raised the plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels compared with values in the control group (p < 0.05). Pre‐treatment of mice with Am.Cr (150–600 mg/kg) significantly prevented the toxins induced rise in plasma ALT and AST (p < 0.05). The hepatoprotective effect of Am.Cr was further verified by histopathology of the liver, which showed improved architecture, absence of parenchymal congestion, decreased cellular swelling and apoptotic cells, compared with the toxin group of animals. In isolated rabbit jejunum preparations, Am.Cr caused a concentration‐dependent (0.3–10 mg/mL) relaxation of both spontaneous and K+‐induced contractions as well as shifting the Ca++ concentration‐response curves (CRCs) to the right, similar to that caused by verapamil. These results indicate that the crude extract of Achillea millefolium exhibits a hepatoprotective effect, which may be partly attributed to its observed calcium channel blocking activity. Copyright © 2006 John Wiley & Sons, Ltd.
Tumor cell‐selective antiproliferative effect of the extract from Morinda citrifolia fruits
Authors: Arpornsuwan Teerakul , Punjanon Tadsanee
Published: April 2006

The methanol extract from Morinda citrifolia fruits was tested for cytotoxicity activity on the MTT assay. The appearance of cytotoxic changes after exposure to the extract was in a concentration dependent manner. The median lethal concentrations (LC50) of the extract in baby hamster kidney (BHK) cells, African green monkey kidney (Vero) cells and human laryngeal carcinoma (Hep2) cells were found to be 2.5, 3 and 5 mg/mL, respectively. A concentration of 0.1 mg/mL of crude extract exhibited cytotoxic activity against breast cancer (MCF7) and neuroblastoma (LAN5) cell lines at 29% and 36%, respectively. The same concentration of extract showed no toxicity to Vero and very little toxicity to BHK (6%) and Hep2 (13%) cells. Copyright © 2006 John Wiley & Sons, Ltd.
Immunomodulatory effects of methoxylated flavonoids from two Chromolaena species: structure‐activity relationships
Authors: Taleb‐Contini S. H. , Kanashiro A. , Kabeya L. M. , Polizello A. C. M. , Lucisano‐Valim Y. M. , Oliveira D. C. R.
Published: April 2006

Excessive generation of reactive oxygen species (ROS) by polymorphonuclear leukocytes (PMNL) is involved in the pathology of many inflammatory diseases. Compounds isolated from natural sources with antioxidant activity can be helpful to inhibit and/or modulate the oxidative damage associated with PMNL‐derived ROS. The present study investigated the relationship between the chemical structure of five methoxylated flavonoids, isolated from Chromolaena hirsuta and Chromolaena squalida, and their inhibitory activity on ROS generation by opsonized zymosan‐stimulated PMNL. The antioxidant efficacy of the studied flavonoids, assessed by luminol‐dependent chemiluminescence, was dependent on the position and number of methoxy and hydroxy groups. Copyright © 2006 John Wiley & Sons, Ltd.
Antioxidant activity of wild plants collected in valsesia, an alpine region of Northern Italy
Authors: Vitalini S. , Grande S. , Visioli F. , Agradi E. , Fico G. , Tome F.
Published: April 2006

A selection of wild plants collected in Valsesia (Northwest Italy) was screened for their in vitro antioxidant activity. Aerial parts of selected plants were dried at room temperature and powdered. Then, four sequential extractions were performed with increasing polarity solvents, i.e. n‐hexane, chloroform, chloroform–methanol (9:1, v/v) and methanol. By employing different assays, it was shown that all the methanol extracts of the samples collected were endowed with antioxidant activity, though, as expected, their potency varied according to the different tests. In particular, plants of the Thymus and Achillea genus displayed the highest activity. Given that a diet rich in wild plants is associated with a reduced incidence of degenerative diseases, such as atherosclerosis and cancer, this study suggests that some Valsesia plants could be pharmaceutically exploited. Copyright © 2006 John Wiley & Sons, Ltd.