bluuebunny/crossref_metadata_2025 huggingface dataset:
Neue Technologie zur Herstellung von Wolframschmelzkarbid
Authors: Linke P. , Weiss K. ‐ H. , Nutsch G.
Published: June 2003

Eine vielversprechende Anwendung der ICP Technologie ist die Sphäroidisierung und Verfestigung von porösen, agglomerierten Partikeln. Die agglomerierten Partikel werden durch ein Sprühtrocknungsprozess hergestellt. Das Ausgangsmaterial besteht aus WC/W2C mit einer Korngröße von 90 – 120 μm und einer Kohlenstoffkonzentration von 4,8 Gew. %. Das Ziel des Projektes war, dichte und sphäroidisierte Partikel, mit einer definierten Kohlenstoffkonzentration, im Bereich von 3,8 – 4,3 Gew.%, herzustellen.
Nanokristalline Werkstoffe hergestellt mit dem Thermischen HF‐Plasma
Authors: Blum J. , Herrmann A. , Schwenk A. , Weiss K.‐H. , Nutsch G.
Published: June 2003

Das induktiv gekoppelte Plasma (ICP) eignet sich unter atmosphärischen Bedingungen besonders für das Aufschmelzen und Verdampfen von Werkstoffen. Das elektrodenlose ICP kann ohne Ausnahme mit beliebigen Gasgemischen betrieben werden. Mit der Verwendung eines Argon‐Sauerstoff Hüllgasgemisches des ICP werden Reaktion metall‐organischer, flüssiger Precursoren, die in den heißen Plasmakern injiziert werden, nanokristalline Schichten erzeugt. Für den Beschichtungsprozess wir ein Überschallplasmastrahl eingesetzt. Durch den Aufprall der Partikel auf dem Substrat, das direkt am Düsenausgang des Plasmatrons positioniert ist, werden dünne Schichten hoher Dichte mit Kristallitgrössen von 30‐40 nm erzeugt. Die Struktur und Korngrössen der abgeschiedenen Schichten werden mittels XRD analysiert.
Nanokomposite für die Herstellung oxidischer Matrices keramischer Faserverbundwerkstoffe
Authors: Georgi C. , Schindler U. , Krüger H.‐G. , Kern H.
Published: June 2003

Keramische Suspensionen für die Herstellung oxidischer Faserverbundwerkstoffe werden in der Regel aus Submikropulvern hergestellt. Am Beispiel der elektrophoretischen Infiltration von Nextel™ 720‐ und Nextel™ 650‐ Geweben wird gezeigt, daß auch die Verwendung von Nanopulvern bzw. Nanokompositen für den Matrixaufbau von Vorteil sein kann. So gestattet die Koinfiltration des α‐Aluminiumoxid‐Submikropulvers und einer zweiten, nanoskaligen Phase (Zirkonoxid) den Aufbau einer (α‐Aluminiumoxid + Zirkonoxid)‐ Matrix als strukturelles Komposit. Funktionelle Nanokomposite aus Aluminiumoxid und Siliziumoxid ermöglichen die Mullitbildung und ‐verdichtung bei für die Fasern unschädlichen Temperaturen.
Eigenschaften von nanoskaligen Aluminiumoxid‐ und Titandioxid‐Partikeln in Nickelelektrolyten
Authors: Oberseider M. , Erler F. , Jakob C. , Lampke T. , Steinhäuser S. , Wielage B.
Published: June 2003

Die Untersuchung des Agglomerationsverhaltens von nanoskaligen Partikeln in Abhängigkeit der Konzentration der Einzelbestandteile eines Watts‐Nickelelektrolyten und der mechanischen Konvektion ist Gegenstand dieses Artikels. Ausgehend von der Beschreibung der Messprinzipien werden die Ergebnisse der Zetapotentialmessungen und Bestimmung der Agglomeratgrößen dargestellt, wobei ebenfalls auf die auftretenden Schwierigkeiten bei den Messungen eingegangen wird. Nickelsulfat zeigte die größte Wirkung zur Bildung großer Agglomerate während die Borsäure darauf keinen Einfluss aufwies.
Ergebnisse von Sol‐Gel‐Beschichtungen auf austenitischem CrNi‐Stahl
Authors: Schwarz J. , Svoboda St. , Oertel B.
Published: June 2003

Dünne Al2O3 – Hartstoffschichten wurden mittels Sol‐Gel‐Verfahren auf austenitischem CrNi‐Stahl präpariert und untersucht.

Das Umwandlungsverhalten und die Messungen der Schichteigenspannungen wurden durch Röntgenbeugungsverfahren ermittelt. Ergänzt wurden die Untersuchungen durch Verscheißmessungen.
Nutzung von Werkstoffstrukturgrößen als Messnormale
Authors: Spieß L. , Knedlik Ch.
Published: June 2003

Messen von Längen ist ein Vergleichen/Bewerten von erhaltenen Messsignalen mit einem Standard/Kalibriermassstab. Die Nanotechnik erfordert Messgenauigkeiten vom Submeter bis zum Nanometerbereich, d. h. ein Überstreichen von 9 Größenordnungen. Messmarken und mögliche Messnormale werden nach ihren Erfordernissen klassifiziert und auf Anforderungen, Genauigkeit, Stabilität, Datenmengen und Machbarkeit analysiert. Für eine Nanopositionier‐ und –messmaschine werden Vorschläge für eine Realisierbarkeit zusammengefasst.
Characterization of Indium‐Tin‐Oxide Thin Film Microelectrodes for Biomedical Use
Authors: Jakubec A. , Tvarozek V. , Novotny I. , Rehacek V. , Breternitz V. , Knedlik Ch. , Spiess L.
Published: June 2003

Selected properties of indium‐tin‐oxide (ITO) films prepared by r.f. diode sputtering have been investigated in consideration of surface morphology, optical properties, crystal structure and phase formation, electrical resistivity and chemical resistance. The ITO films showed low electrical resistivity (6·10‐5Ωm), high optical transmittance (> 80 %) and suitable chemical resistance against selected chemicals during 1 hour.
Einfluss von UV‐Laserparametern auf die geometrische Strukturierung von fotosensitivem Glas
Authors: Brokmann U. , Harnisch A. , Hülsenberg D.
Published: June 2003

Der Werkstoff Glas ist zunehmend ein interessanter Konstruktionswerkstoff für die Mikrotechnik. Zur Mikrobearbeitung von fotostrukturierbaren Gläsern wird die Eigenschaft Fotosensibilität im UV‐Bereich ausgenutzt. Als „fotosensibel”︁ gilt ein Glas u. a. dann, wenn es unter Einfluss räumlich begrenzter energiereicher UV‐Strahlung und anschließender thermischer Behandlung nur in den belichteten Bereichen kristallisiert. Die Mikrostrukturierung erfolgt durch anschließendes nasschemisches Ätzen der kristallisierten Bereiche.

Die Belichtung fotosensitiver Gläser mittels konventioneller Maskaligner ist gegenwärtig Stand der Technik. Ein alternatives Verfahren dazu stellt die Belichtung mittels UV‐Laserstrahlung dar.

Es werden Zusammenhänge zwischen Laserparametern und erzeugten Strukturgeometrien diskutiert.
Transluzente oxidfaserverstärkte Glasmatrix‐Verbundwerkstoffe
Authors: Fehling P. , Hülsenberg D. , Raab D. , Mache Th. , Winkler V. , Kern H. , Stöckel S. , Weise, K. , Marx G.
Published: June 2003

Das Ziel der Untersuchungen ist die Entwicklung von transparenten Glasmatrix‐Kompositen. Neben den mechanischen müssen dazu auch die optischen Eigenschaften der Komponenten aneinander angepaßt werden. Der Einfluß unterschiedlicher Faserbeschichtungen (Bornitrid‐, Titandioxid‐Einzelbeschichtung oder Bornitrid/Titandioxid‐Doppelbeschichtung) auf die mechanischen und optischen Eigenschaften von Nextel 440‐Faser verstärktem Glas wird untersucht. Mikromechanische Untersuchungen (push‐in Tests) und 3‐Punktbiegeversuche erbrachten die größte Verbesserung der Bruchzähigkeit für die Verbunde mit Bornitrid/Titandioxid‐doppelbeschichteten Fasern. Die Verbunde mit Bornitrid bzw. Titandioxid Einzelschichten wurden durch Transmissionsmessungen im sichtbaren Spektralbereich charakterisiert.
Magnetische Mikrokomponenten für die Mikroreaktionstechnik
Authors: Halbedel B. , Albrecht A. , Frank Th. , Henkel Th. , Kunze U. , Mayer G. , Schober A. , Wurmus H.
Published: June 2003

Miniaturisierung und Parallelität chemischer und molekularbiologischer Prozessen erfordern die Entwicklung neuer μ‐Scale‐Lösungen. Reaktionskammerarrays mit weniger als 1 μl sind bereits verfügbar, jedoch das größere technische Problem, das verbleibt , ist das Handling, vornehmlich der Transfer der Substanzen im nl‐Bereich zwischen den Kammern. Dafür wurde ein neuartiger Lösungsansatz mit magnetischen Funktionskugeln, die Festphasenreaktionen ermöglichen, entwickelt und ein neues Handlingssystem mit magnetischen Transferplatten konzipiert, das einen parallelen und selektiven Substanztransfer auch zwischen miniaturisierten Reaktionskammerarrays mit mehreren tausend Kammern gestattet.
Oberflächenspannungsmesstechnik für den Prozesseinsatz
Authors: Haberland R. , Krause W.
Published: June 2003

Bei der Reinigung von Oberflächen ist das Einhalten der optimalen Tensidkonzentration für die Prozesssicherheit entscheidend. Die Konzentration der freien Tenside ist messbar, indem die Oberflächenspannung erfasst wird. Die SITA Messtechnik GmbH hat einen neuartigen Sensor auf der Basis der Blasendifferenzdruckmethode entwickelt, der eine kontinuierliche Messung der Oberflächenspannung bei hoher Standzeit ermöglicht. Mit dessen Anwendung zum Überwachen von Reinigungsbädern ergeben sich Einsparpotentiale hinsichtlich Rohstoffeinsatz, Entsorgung und Fehlerfolgekosten.
The Dynamic Indentation Method in Diagnostics of the Mechanical Properties of Coatings
Authors: Minchenia V. V.
Published: June 2003

The application of the dynamic indentation method for estimation of the hardness of coated structures has been investigated.
Simultaneous tridiagonalization of two symmetric matrices
Authors: Garvey Seamus D. , Tisseur Françoise , Friswell Michael I. , Penny John E. T. , Prells Uwe
Published: June 2003

We show how to simultaneously reduce a pair of symmetric matrices to tridiagonal form by congruence transformations. No assumptions are made on the non‐singularity or definiteness of the two matrices. The reduction follows a strategy similar to the one used for the tridiagonalization of a single symmetric matrix via Householder reflectors. Two algorithms are proposed, one using non‐orthogonal rank‐one modifications of the identity matrix and the other, more costly but more stable, using a combination of Householder reflectors and non‐orthogonal rank‐one modifications of the identity matrix with minimal condition numbers. Each of these tridiagonalization processes requires O(n3) arithmetic operations and respects the symmetry of the problem. We illustrate and compare the two algorithms with some numerical experiments. Copyright © 2003 John Wiley & Sons, Ltd.
Symmetric Galerkin BEM for shear deformable plates
Authors: Perez‐Gavilan J. J. , Aliabadi M. H.
Published: June 2003

A symmetric Galerkin boundary element formulation is developed for shear deformable plates. A mixed strategy is used for the integration process, i.e. partial regularization using simple solutions followed by a singularity subtraction technique. For the shear equation, full regularization is achieved using new kernel relationships found through a constant shear mode of deformation. Some of the strong singular integrals are avoided altogether by using a modified traction obtained through a very simple variable change; appropriate boundary conditions are defined. Details of the implementation are given and several example problems solved to verify the accuracy of the proposed formulation. Copyright © 2003 John Wiley & Sons, Ltd.
A novel 3D mixed finite‐element model for statics of angle‐ply laminates
Authors: Desai Y. M. , Ramtekkar G. S. , Shah A. H.
Published: June 2003

Analysis of angle‐ply laminates becomes critical and computationally involved because of the presence of extension–shear coupling. A refined three‐dimensional, mixed, 18‐node finite element (FE) model has been developed to analyse angle‐ply laminates under static loading. The minimum potential energy principle has been used for the development of the mixed FE model, where the transverse stress components (τxz, τyz and σz, where z is the thickness direction) have been incorporated as the nodal degrees of freedom, in addition to the three displacement fields. Further, continuity of transverse stress fields through the thickness of the plate and layerwise continuity of displacement fields have been enforced in the formulation. Because all the constitutive and the compatibility conditions have been ensured within the continuum, the present formulation is unique amongst the family of mixed FE models. Results have been obtained for various angle‐ply laminates and compared with analytical and finite‐element solutions, which have been found to be in good agreement with them. Some new results on angle‐ply with clamped–clamped support condition have also been presented to serve as benchmark results. Copyright © 2003 John Wiley & Sons, Ltd.
Checkerboard‐free topology optimization using non‐conforming finite elements
Authors: Jang Gang‐Won , Jeong Je Hyun , Kim Yoon Young , Sheen Dongwoo , Park Chunjae , Kim Myoung‐Nyoun
Published: June 2003

The objective of the present study is to show that the numerical instability characterized by checkerboard patterns can be completely controlled when non‐conforming four‐node finite elements are employed. Since the convergence of the non‐conforming finite element is independent of the Lamé parameters, the stiffness of the non‐conforming element exhibits correct limiting behaviour, which is desirable in prohibiting the unwanted formation of checkerboards in topology optimization. We employ the homogenization method to show the checkerboard‐free property of the non‐conforming element in topology optimization problems and verify it with three typical optimization examples. Copyright © 2003 John Wiley & Sons, Ltd.
A discontinuous Galerkin finite element method for dynamic and wave propagation problems in non‐linear solids and saturated porous media
Authors: Li Xikui , Yao Dongmei , Lewis R. W.
Published: June 2003

A time‐discontinuous Galerkin finite element method (DGFEM) for dynamics and wave propagation in non‐linear solids and saturated porous media is presented. The main distinct characteristic of the proposed DGFEM is that the specific P3–P1 interpolation approximation, which uses piecewise cubic (Hermite's polynomial) and linear interpolations for both displacements and velocities, in the time domain is particularly proposed. Consequently, continuity of the displacement vector at each discrete time instant is exactly ensured, whereas discontinuity of the velocity vector at the discrete time levels still remains. The computational cost is then obviously saved, particularly in the materially non‐linear problems, as compared with that required for the existing DGFEM. Both the implicit and explicit algorithms are developed to solve the derived formulations for linear and materially non‐linear problems. Numerical results illustrate good performance of the present method in eliminating spurious numerical oscillations and in providing much more accurate solutions over the traditional Galerkin finite element method using the Newmark algorithm in the time domain. Copyright © 2003 John Wiley & Sons, Ltd.
A gradientless technique for optimal distribution of piezoelectric material for structural control
Authors: Mukherjee A. , Joshi S. P.
Published: June 2003

Application of smart piezoelectric materials in structural control is gaining momentum. Optimum placement and actuation of the smart material is an aspect of paramount importance in such structures. In this paper, we present an iterative technique to optimize the shape of piezoelectric actuators in order to achieve the desired shape of the structure. A C0‐continuous eight‐node plate finite element with five degrees of freedom is employed. A gradientless shape design procedure based on the residual voltages is developed. It aims at minimizing the quadratic measure of the global displacement residual error between the desired and the current structural configuration. The actuators gradually adapt to a shape that is most efficient in resisting the external excitation. The present technique can be well suited for any static and time‐varying excitation. In vibration control it is often necessary to create modal sensors and actuators in order to observe or excite some specific modes. Such modal sensors and actuators alleviate spillover problems and thus they avoid exhaustive signal processing. Several numerical examples for static as well as dynamic cases are presented to demonstrate the efficacy of the present technique. Copyright © 2003 John Wiley & Sons, Ltd.
Numerical simulation of convective heat and mass transfer in banks of tubes
Authors: Comini G. , Croce G.
Published: June 2003

This paper studies convective heat and mass transfer in laminar flows of humid air through banks of tubes. The flow structure on the airside is spatially periodic, with fully developed conditions prevailing after a short distance from the inlet section. In numerical simulations, periodicities in the velocity, temperature and mass concentration fields are taken into account to reduce the computational domain, both in the entrance region and in the fully developed region. The approach followed is completely general, even if the finite element method is used in the discretization process. In the application section, velocity, temperature and mass concentration fields are computed for a bank of tubes in a staggered arrangement. Quantitative results are also obtained for apparent friction factors, Nusselt numbers, Sherwood numbers and ratios between Colburn factors for heat and mass transfer. Copyright © 2003 John Wiley & Sons, Ltd.
A medieval bladder stone from Norwich, Norfolk
Authors: Anderson T.
Published: June 2003

A fragmented bladder stone was recovered from the pelvic cavity of a medieval mature male buried in the Franciscan cemetery of St Faith's, Norwich. A review of other British archaeologically derived bladder stones is also included. Copyright © 2003 John Wiley & Sons, Ltd.
Marked occupational dental abrasion from medieval Kent
Authors: Turner Graham , Anderson Trevor
Published: June 2003

A medieval male skeleton displays marked dental abrasion which is considered to be occupational, possible related to carpentry. Copyright © 2003 John Wiley & Sons, Ltd.
Evidence of interpersonal violence at the Chalcolithic village of Shiqmim (Israel)
Authors: Dawson L. , Levy T. E. , Smith P.
Published: June 2003

Three circumscribed depressed fractures were found on the skull of an adolescent boy recovered from a primary intramural burial at the Chalcolithic site of Shiqmim, northern Negev, Israel dated to (∼4500–3200 BCE). The fractures were located on the left side and back of the skull. They are circular in outline and have sharp margins containing numerous small bone fragments. These indicate that the skull was fractured when the bone was still fresh and were the probable cause of death. The location of the fractured areas is typical of blows inflicted by a right‐handed individual in face‐to‐face conflict. The size and shape of the fractures, suggests that they were inflicted by a blunt instrument, possibly a mace head. The absence of any signs of healing or infection indicates that all fractures occurred within a short space of time and resulted in death. Neither biological characteristics nor burial pattern show any unique features that distinguish this individual from others recovered at this site. Copyright © 2003 John Wiley & Sons, Ltd.
The application of ancient DNA analysis to identify neolithic caprinae: a case study from the site of Hatoula, Israel
Authors: Kahila Bar‐Gal Gila , Ducos Pierre , Kolska Horwitz Liora
Published: June 2003

The evidence for wild sheep (Ovis orientalis) in archaeological sites from the southern Levant is examined through the application of ancient DNA analysis to specimens from the Pre‐Pottery Neolithic A (8300–7500 uncal. BC) site of Hatoula, Israel. The results indicate that at least one of the bones from this site, previously identified as sheep, is in fact goat. To date this is the earliest faunal sample to have yielded DNA in the region. This study highlights the problems in applying morphological criteria to distinguish between caprine species, and illustrates how ancient DNA analysis can serve as a powerful tool in resolving questions of species attribution. Copyright © 2003 John Wiley & Sons, Ltd.
Congenital absence of the patella in an Anglo‐Saxon skeleton
Authors: Patrick P. , Waldron T.
Published: June 2003

A skeleton of a young Anglo‐Saxon woman aged about 25 years at the time of death is described. The distal femoral articulation was in two distinct parts separated by a deep groove in which the tendon of quadriceps femoris would have lain. The medial condyle of the femur was smaller than normal and there was no patellar surface on the anterior part of the articulation. The woman was of normal stature (1.53 ± 0.04 m) and no other abnormalities were found in the skeleton. It was considered that these findings were consistent with a diagnosis of congenital absence of the patella. This is the earliest recorded case of this condition. Copyright © 2003 John Wiley & Sons, Ltd.
Chemical Kinetics and Heat Transfer Issues for a Safe Bench Scale Production of Partially Triazole Substituted Glycidyl Azide Polymer (GAP)
Authors: Dubois Charles , Désilets Sylvain , Nadeau Gaston , Gagnon Nicole
Published: June 2003

The reaction of azido polymers with double and triple bonds of light olefins can lead to triazole and aziridine cycles formation on the azide bearing sites of the polymer. An experimental investigation of the burning behaviour of these modified polymers has shown that triazole substituted GAPs exhibit a higher burning rate at low pressure, which may be a desirable characteristic for ducted rocket applications. However, the chemical reaction of interest is highly exothermic and as such, it represents a significant safety risk when conducted in bulk. In order to reduce this risk, we have assessed the chemical kinetics of triazole formation by NMR spectroscopy and linked this information with DSC measurements to produce a safe procedure for the synthesis of GAP‐triazole polymer in a chemical reactor.
Hazard Characterization of Aluminum Nanopowder Compositions
Authors: Jones David E. G. , Turcotte Richard , Fouchard Robert C. , Kwok Queenie S. M. , Turcotte Anne‐Marie , Abdel‐Qader Zainab
Published: June 2003

The thermal behaviour in air of two Al nanopowders, Alss and Alsstef, a Teflon coated version of Alss, was determined using DSC, TG‐DTA and accelerating rate calorimetry (ARC). Compared to two larger Al nanopowders, for which hazards results have been reported, Alss and Alsstef are less reactive in air, possibly due to the nature of the passivating and coating layers. The stability of Alss and Alsstef in a wet environment was also investigated using ARC. Alss is very reactive with water, which could lead to a problem of aging in a humid atmosphere. The ”coating” of Alsstef significantly reduces the reactivity of Alss with water. Outgassing behaviour of mixtures of ADN, GAP and various Al powders was investigated using TG‐DTA‐FTIR‐MS. No chemical interactions were observed between ADN/Al, GAP/Al and ADN/GAP. The effect of the addition of Al nanopowders on the thermal decomposition of ADN and GAP was studied using ARC. Al nanopowders had a minor effect on the thermal stability of ADN, while the addition of Alss and Alsstef lowered the onset temperature of GAP. The electrostatic discharge (ESD), impact and friction sensitivities of Al nanopowders and their mixtures with ADN and GAP were also determined. Al nanopowders appear to sensitize ADN to ESD, impact and friction.
A Simple Method for the Purification of Crude Hexanitrohexaazaisowurtzitane (HNIW or CL20)
Authors: Bellamy Anthony J.
Published: June 2003

A simple method for purifying crude hexanitrohexaazaisowurtzitane (HNIW or CL20) to analytical purity is described. This involves filtering a solution of HNIW in heptane / ethyl acetate through a column of Darco activated carbon type G‐60 (∼20 g carbon/g HNIW). The method works extremely well for HNIW derived from 4,10‐diformyl‐2,6,8,12‐tetraacetylhexaazaisowurtzitane (final purity>99.95%, ∼90% recovery), and reasonably well for HNIW derived from 4,10‐dibenzyl‐2,6,8,12‐tetraacetylhexaazaisowurtzitane.
Structure and Bonding in 2‐Diazo‐4,6‐Dinitrophenol (DDNP)
Authors: Holl Gerhard , Klapötke Thomas M. , Polborn Kurt , Rienäcker Claudia
Published: June 2003

The structure and bonding in 2‐diazo‐4,6‐dinitrophenol (DDNP) is discussed on the basis of quantitative molecular orbital (MO) calculations at the density functional theory (DFT) level using the natural bond orbital analysis (NBO). Qualitative valence bond theory (VB) was used to generate an increased VB structure for DDNP. The increased‐valence structure is better in accordance with the computed and observed (X‐ray) geometry than is the NBO analysis.
The Use of theTrifluoroacetyl Protecting Group in the Synthesis of Mono‐ (4) and Di‐Amines (4,10) in the Polynitrohexaazaisowurtzitane Series
Authors: Bellamy Anthony J. , MacCuish Alistair , Golding Peter
Published: June 2003

The first rational synthesis of the mono‐amine 2,6,8,10,12‐pentanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane (II) and the di‐amine 2,6,8,12‐tetranitro‐2,4,6,8,10,12‐hexaazaisowurtzitane (III) is described. Both syntheses exploit the selectivity, under nitrolysis conditions, between an N‐acetyl group and an N‐trifluoroacetyl group, and the ease with which an N‐trifluoroacetyl group can be hydrolytically removed.
Peptide related drug research
Authors: Bajusz Sándor
Published: June 2003

Drug discovery directed peptide research has been pursued at the IVAX Drug Research Institute (formerly Institute for Drug Research) (IDR) since the mid 1950s. Outlined are the main projects and the most significant results, which include the first synthesis of human ACTH, the discovery of GYKI‐14 166, the prototype of peptide inhibitors of thrombin, a stable anticoagulant, efegatran GYKI‐14 766, and their dual acting analogues. The identification of an agonist analogue of LHRH leading to Cetrorelix, an LHRH antagonist now in clinical use, is also presented. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Synthetic formyl tripeptide chemoattractants: a Cα, α‐dialkylated, amphiphilic glycyl residue at position 1
Authors: Witkowska Renata , Zabrocki Janusz , Spisani Susanna , Sofia Falzarano Maria , Toniolo Claudio , Formaggio Fernando
Published: June 2003

The two diastereomeric tripeptides f‐(S)‐HmMet‐Leu‐Phe‐OMe and f‐(R)‐HmMet‐Leu‐Phe‐OMe, analogues of the prototypical chemoattractant f‐Met‐Leu‐Phe‐OH, were synthesized in solution by classical methods and fully characterized. A conformational study was performed in solution by 1H‐NMR. Concomitantly, the two peptides were tested for their ability to induce chemotaxis, superoxide anion production and lysozyme secretion from human neutrophils. The conformational and biological data are discussed with regard to the proposed model of the chemotactic receptor on neutrophils. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Mass spectrometric analysis of combinatorial peptide libraries derived from the tandem repeat unit of MUC2 mucin
Authors: Schlosser Gitta , Takáts Zoltán , Vékey Károly , Pócsfalvi Gabriella , Malorni Antonio , Windberg Emöke , Kiss Andrea , Hudecz Ferenc
Published: June 2003

Four 19‐member synthetic peptide libraries, based on the TX1TX2T epitope motif of the mucin‐2 gastrointestinal glycoprotein (MUC2) and ranging in peptide length from dipeptides to 15‐mers (XT, TXT, TQTXT and KVTPTPTPTGTQTXT), were synthesized by combinatorial solid phase peptide synthesis using the portioning‐mixing combinatorial approach, and analysed by electrospray ionization mass spectrometry at different (1000–10 000) resolutions. Most of the components of the individual libraries could be easily identified in a single‐stage molecular mass screening experiment. The resolving power of the instrument becomes an important factor above 800–1000 Da molecular mass, when predominantly multiply charged molecular ions are formed. Approaches to the identification of isobars (glutamine/lysine), isomers (leucine/isoleucine) and sequence variations by tandem mass spectrometry, and/or by high‐performance liquid chromatography‐mass spectrometry are outlined. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Nascent helix in the multiphosphorylated peptide αS2‐casein(2–20)
Authors: Huq N. Laila , Cross Keith J. , Reynolds Eric C.
Published: June 2003

Sequence‐specific nuclear magnetic resonance (NMR) assignments have been determined for the peptide αS2‐CN(2–20) containing the multiphosphorylated motif‐8Ser(P)‐Ser(P)‐Ser(P)‐Glu‐Glu12‐ in the presence of molar excess Ca2+. The secondary structure of the peptide was characterized by sequential (i,i + 1), medium‐range (i,i + 2/3/4) nOes and Hα chemical shifts. Molecular modelling of the peptide based on these constraints suggests a nascent helix for residues Ser(P)9 to Glu12. The spectral data for αS2‐CN(2–20) were compared with those of other casein phosphopeptides β‐CN(1–25) and αS1‐CN(59–79) that also contain the multiphosphorylated motif. This comparison revealed a similar pattern of secondary amide chemical shifts in the multiphosphorylated motif. However, the patterns of medium‐range nOe connectivities in the three peptides suggests they have distinctly different conformations in the presence of Ca2+ despite having a high degree of sequential similarity. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
The number needed to treat: a useful clinical measure or a case of the Emperor's new clothes?
Authors: Grieve Andrew P.
Published: June 2003

The number needed to treat (NNT) was introduced into the medical literature as an easily understood and useful measure of treatment effect for clinical trials in which the main outcome variable is binary. It has been argued that it is more easily understood by practising physicians than more statistically based measures. In this paper we review the claims made for the NNT and question whether it is truly understandable to physicians, and look at issues around determining a confidence interval, or a Bayesian interval, for the NNT. Copyright © 2003 John Wiley & Sons, Ltd.
Negative binomial control limits for count data with extra‐Poisson variation
Authors: Hoffman David
Published: June 2003

Traditional techniques for calculating control limits for processes with discrete responses are based on the Poisson distribution. However, for many processes, the assumption of a Poisson distribution is violated. In such cases, use of traditional Poisson control limits may result in an inflated risk of Type I error. The negative binomial distribution is a natural extension of the Poisson distribution and allows for over‐dispersion relative to the Poisson distribution. A simple approach to calculating exact and approximate control limits for count data based on the negative binomial distribution is described. The approach is illustrated by application to water bacteria count data taken from a water purification system. Copyright © 2003 John Wiley & Sons, Ltd.
Antibacterial activity of medicinal plant extracts against periodontopathic bacteria
Authors: Iauk L. , Lo Bue A. M. , Milazzo I. , Rapisarda A. , Blandino G.
Published: June 2003

This study was performed to evaluate the antibacterial activity of Althaea ofﬁcinalis L. roots, Arnica montana L. ﬂowers, Calendula ofﬁcinalis L. ﬂowers, Hamamelis virginiana L. leaves, Illicium verum Hook. fruits and Melissa ofﬁcinalis L. leaves, against anaerobic and facultative aerobic periodontal bacteria: Porphyromonas gingivalis, Prevotella spp., Fusobacterium nucleatum, Capnocytophaga gingivalis, Veilonella parvula, Eikenella corrodens, Peptostreptococcus micros and Actinomyces odontolyticus. The methanol extracts of H. virginiana and A. montana and, to a lesser extent, A. ofﬁcinalis were shown to possess an inhibiting activity (MIC ≤ 2048 mg/L) against many of the species tested. In comparison, M. ofﬁcinalis and C. ofﬁcinalis extracts had a lower inhibiting activity (MIC ≥ 2048 mg/L) against all the tested species with the exception of Prevotella sp. Illicium verum methanol extract was not very active though it had a particular good activity against E. corrodens. The results suggest the use of the alcohol extracts of H. virginiana, A. montana and A. ofﬁcinalis for topical medications in periodontal prophylactics. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of Coccinia indica leaf extract on plasma antioxidants in streptozotocin‐ induced experimental diabetes in rats
Authors: Venkateswaran S. , Pari L.
Published: June 2003

The present study was carried out to investigate the antioxidant effect of an ethanolic extract of Coccinia indica leaves, an indigenous plant used in Ayurvedic Medicine in India, in Streptozotocin‐diabetic rats. Oral administration of Coccinia indica leaf extract (CLEt) (200 mg/kg body weight) for 45 days resulted in a signiﬁcant reduction in plasma thiobarbituric acid reactive substances, hydroperoxides, vitamin E and ceruloplasmin. The extract also caused a signiﬁcant increase in plasma vitamin C and reduced glutathione, which clearly shows the antioxidant property of CLEt. The effect of CLEt at 200 mg/kg body weight was more effective than glibenclamide. Copyright © 2003 John Wiley & Sons, Ltd.
The cytotoxicity of methyl protoneogracillin (NSC‐698793) and gracillin (NSC‐698787), two steroidal saponins from the rhizomes of Dioscorea collettii var. hypoglauca, against human cancer cells in vitro
Authors: Hu Ke , Yao Xinsheng
Published: June 2003

In our continuous studies of anticancer activity of steroidal saponins from the rhizomes of Dioscorea collettii var. hypoglauca (Dioscoreaceae), methyl protoneogracillin (NSC‐698793) and gracillin (NSC‐698787) were tested for cytotoxicity against human cancer cell lines from leukemia and eight solid tumor diseases. As a result, methyl protoneogracillin was cytotoxic against all the test cell lines with GI50 < 100 µM, especially selectively against two leukemia lines (CCRF‐CEM and RPMT‐8226), one colon cancer line (KM12), two central nervous system (CNS) cancer lines (SF‐539 and U251), one melanoma line (M14), one renal cancer line (786‐0), one prostate cancer line (DU‐145), and one breast cancer line (MDA‐MB‐435), with GI50 ≤ 2.0 µM. Leukemia, CNS cancer, and prostate cancer were the most sensitive subpanels, while ovarian cancer was the least sensitive subpanels. The preliminary toxicity studies showed that the maximum tolerant dose was 600 mg/kg for methyl protoneogracillin to mice. Gracillin was cytotoxic against most cell lines with GI50, TGI and LC50 at micromolar levels, but no activity against EKVX (non‐small cell lung cancer), HT29 (colon cancer), OVCAR‐5 (ovarian cancer), and SN12C (renal cancer). Based on structure‐activity relationship, C‐25 R/S conﬁguration was critical for leukemia selectivity between methyl protoneogracillin and methyl protogracillin. F‐ring was critical to selectivity between furostanol (methyl protoneogracillin and methyl protogracillin) and spirostanol (gracillin) saponins in this study. By an analysis of COMPARE software, no compounds in the NCI's database had similar mean graphs to those of methyl protoneogracillin and gracillin, respectively, indicating potential novel mechanism(s) of action involved. Put all in together, methyl protoneogracillin has been selected as a potential anticancer candidate for hollow ﬁber assay to nude mice, but gracillin will not be pursued due to lack of selectivity against human cancer diseases. Copyright © 2003 John Wiley & Sons, Ltd.
Effects of soybean ethanol extract on the cell survival and oxidative stress in osteoblastic cells
Authors: Choi Eun Mi , Koo Sung Ja
Published: June 2003

Recent evidence suggests that high concentrations of tumor necrosis factor‐α (TNF‐α) and nitric oxide (NO) are thought to increase the apoptosis in osteoblasts and bone resorption and may have important roles in the regulation of osteoblast and osteoclast metabolism, especially in rheumatoid arthritis. The present study was performed to investigate the effect of soybean ethanol extract on the scavenging properties using DPPH and the TNF‐α and NO production of osteoblastic MC3T3‐E1 cells. The soy extract and its fractions according to polarity displayed a strong free radical scavenger activity at 0.01∼0.1g/L, except for aquous fraction which had no signiﬁcant effect on the function of MC3T3‐E1 cells (p < 0.05). TNF‐α secretion by MC3T3‐E1 cells was reduced signiﬁcantly when stimulated with soy extract (0.05 g/L). Nitrite accumulation in culture medium and apoptosis of MC3T3‐E1 cells were induced by the addition of 10−10 M TNF‐α, and inhibited by the simultaneous addition of soy extract (0.05g/L). Copyright © 2003 John Wiley & Sons, Ltd.
Relaxant effect of essential oil and hydro‐alcoholic extract of Pycnocycla spinosa Decne. exBoiss. on ileum contractions
Authors: Sadraei H. , Asghari G. , Naddafi A.
Published: June 2003

Pycnocycla spinosa is an essential oil from a wild plant growing in central Iran. However, so far its pharmacological effects have not been studied. The aim of this study was to look for relaxant effects of the essential oil and hydro‐alcoholic extract of P. spinosa on rat isolated ileum contractions induced by KCl and acetylcholine (ACh). P. spinosa essential oil (PSEO) and the hydro‐alcoholic extract inhibited the response to 80 mM KCl in a concentration‐dependent manner and attenuated the maximum attainable response of ACh concentration‐response curve. Furthermore, in caster oil induced diarrhoea, the hydro‐alcoholic extract had a dose‐dependent anti‐diarrhoeal effect. This study showed that P. spinosa essential oil and its hydro‐alcoholic extract act as a relaxant of rat isolated ileum. As the inhibition of contractile over‐activity of the ileum is the basis for the treatment of gastro‐intestinal disorders such as diarrhoea, P. spinosa may have clinical beneﬁts for treatment of this condition. Copyright © 2003 John Wiley & Sons, Ltd.
Different responses of three rodent Plasmodia species, Plasmodium yoelii 17XL, P. berghei NK65 and P. chabaudi AS on treatment with febrifugine and isofebrifugine mixture from Hydrangea macrophylla var. Otaksa leaf in ICR mice
Authors: Ishih Akira , Miyase Toshio , Ohori Kaneo , Terada Mamoru
Published: June 2003

The antimalarial activity of Hydrangea macrophylla var. Otaksa alkaloids was evaluated against Plasmodium yoelii 17XL, P. berghei NK65 and P. chabaudi AS in ICR mice. For trials in P. yoelii 17XL or P. chabaudi AS infections, mice were infected intraperitoneally with 105, 106 and 107 parasitized erythrocytes, respectively, and in P. berghei NK65 infections, mice were infected intraperitoneally with 103, 104 and 105 parasitized erythrocytes, respectively. Three days after injection, mice were orally given febrifugine and isofebrifugine mixture at 1 mg/kg in the treated group and 0.5% cremophor EL solution in the untreated, infected one, respectively, twice a day for 5 consecutive days. In P. yoelii 17XL infections, mice in all the non‐treated controls died from 5 to 9 dpi with a gradual body weight loss and increasing parasitemias. In the treated groups, the mouse body weight gradually decreased after the end of administration but turned to increase in several days, and except one mouse in the group given 106 parasitized erythrocytes, other mice survived during the experiment. Mice given orally the mixture showed low parasitemia levels during administration. Following a transient recrudescence of malaria parasites in the bloodstream of treated mice, no parasites could be detected by a microscopic examination. In P. berghei NK65 infections, mice in all the non‐treated controls died from 7 to 12 dpi with a gradual body weight loss and increasing parasitemias. In the treated groups, the body weight gradually decreased from 11 dpi and all mice died from 12 to 30 dpi. During a mixture administration all mice showed slight suppression of multiplication of malaria parasites. After the end of administration, however, malaria parasites increased in the bloodstream of the treated mice and all mice died. In P. chabaudi AS infections, there were two different patterns in the course of infection; lethal infection or recovery in both the non‐treated control and treated groups. In the non‐treated and treated groups, mice showed a gradual body weight loss. But the body weights of survivals in both groups turned to increase in several days. Mice in control and treated groups showed as the same profile in the changes of parasitemia. In the non‐treated controls, after a transient peak parasitemia malaria parasites in the bloodstream of survivals could not be detected by a microscopic examination. During a mixture administration, all mice showed suppression of multiplication of malaria parasites. After the end of medication, some mice died with increasing parasitemia. After a transient recrudescence, however, malaria parasites in the bloodstream of survivals could not be detected by a microscopic examination. Copyright © 2003 John Wiley &Sons, Ltd.
HPLC fingerprinting and estimation of the bioactive components of Clutia richardiana L. as a potential hypoglycemic herbal tea
Authors: Abourashed Ehab A. , Ganzera Markus , Khan Ikhlas A. , Khan Shabana , Mossa Jaber S. , El‐Feraly Farouk S.
Published: June 2003

Clutia richardiana L. is a traditional medicinal herb with demonstrated hypoglycemic effects. An HPLC method (Luna® C18 column, gradient elution, UV detection at 220 nm) has been utilized to determine the levels of the major diterpenes of C. richardiana in extracts obtained by using three different solvents. Extraction with the organic solvents methanol and acetonitrile was more efficient than aqueous extraction with hot water, but nine markers could be detected equally in all extracts. The aqueous extract was non‐toxic against a number of human cell lines, which is a promising indication for its use as a safe and effective antidiabetic herbal preparation. Copyright © 2003 John Wiley & Sons, Ltd.
Anti‐inflammatory and immunomodulatory activities of polysaccharide from Chlorella stigmatophora and Phaeodactylum tricornutum
Authors: Guzmán S. , Gato A. , Lamela M. , Freire‐Garabal M. , Calleja J. M.
Published: June 2003

Crude polysaccharide extracts were obtained from aqueous extracts of the microalgae Chlorella stigmatophora and Phaeodactylum tricornutum. The crude extracts were fractionated by ion‐exchange chromatography on DEAE‐cellulose columns. The molecular weights of the polysaccharides in each fraction were estimated by gel filtration on Sephacryl columns. The crude polysaccharide extracts of both microalgae showed anti‐inflammatory activity in the carrageenan‐induced paw edema test. In assays of effects on the delayed hyper‐sensitivity response, and on phagocytic activity assayed in vivo and in vitro, the C. stigmatophora extract showed immunosuppressant effects, while the P. tricornutum extract showed immunostimulatory effects. Copyright © 2003 John Wiley & Sons, Ltd.
Plants for male fertility regulation
Authors: Kamal Raka , Gupta R. S. , Lohiya N. K.
Published: June 2003

The importance of drugs of plant origin in the pursuit of fertility regulating agents for the male from natural products has long been recognized. This review includes 80 plants with 205 references, up to year 2002. The type of extract, dose, animal model and pharmacological activity of these materials have been reviewed in this paper to add impetus to further research and collaboration to resolve the problem of population explosion. Copyright © 2003 John Wiley & Sons, Ltd.
Pycnogenol® prevents haemolytic injury in G6PD deficient human erythrocytes
Authors: Sharma S. C. , Sharma S. , Gulati O. P.
Published: June 2003

Glucose6 phosphate dehydrogenase (G6PD) deficiency is the most common X‐linked disorder of human erythrocytes where cells have inadequate capacity to destroy peroxides and high susceptibility towards haemolytic changes. Pycnogenol® is a proprietary dry extract of the French Maritime pine (Pinus pinaster) bark with high ability to scavenge free radicals. In the present study we have investigated if Pycnogenol® can protect G6PD deficient erythrocytes against haemolytic cell damage. Venous blood samples were obtained from six subject of Mediterranean origin with known G6PD deficiency which was also confirmed with standard techniques. Erythrocyte haemolysis in the presence and absence of Pycnogenol® was induced either with tert‐butylhydroperoxide (t‐BHP) or quinine and the haemoglobin release in the supernatant was determined by recording the optical density at 540 nm in a Shimadzu spectrophotometer. Our results have shown that Pycnogenol® has protective action against a Xenobiotic chemical induced haemolysis in G6PD deficient human erythrocytes. Copyright © 2003 John Wiley & Sons, Ltd.
Antiplasmodial activity of extracts and quassinoids isolated from seedlings of Ailanthus altissima (Simaroubaceae)
Authors: Okunade Adewole L. , Bikoff Rachel E. , Casper Steven J. , Oksman Anna , Goldberg Daniel E. , Lewis Walter H.
Published: June 2003

Extracts and isolated compounds from seedlings of Ailanthus altissima, were assessed for antiplasmodial activity in vitro. Two quassinoids, ailanthone and 6α‐tigloyloxychaparrinone, isolated from the active extracts showed activity against both chloroquine‐resistant and chloroquine‐sensitive strains of Plasmodium falciparum in vitro. Only ailanthone demonstrated low toxicity against the Vero cell line (kidney cells from the African green monkey). This is the first report of the isolation and antiplasmodial activity of 6α‐tigloyloxychaparrinone from this species. Copyright © 2003 John Wiley & Sons, Ltd.
Dimension related distance and its application in QSAR/QSPR model error estimation
Authors: Xu Yong‐jin , Gao Hua
Published: June 2003

In this paper, the concept of dimension related distance (DRD) is introduced to measure the position of a test compound in the descriptor space of training set compounds in a QSAR/QSPR model. DRD can be used to perform similarity comparison between one compound and a group of compounds. In a QSAR/QSPR model, we find that prediction error is related to the similarity between a test compound and the model training set compounds. DRD seems able to capture this similarity and make it possible to estimate prediction error range of a test compound from calculated DRD.
Comparison of Principal Analysis and the Tucker3 Model
Authors: Morais Helena , Ramos Cristina , Forgács Esther , Jakab Annamaria , Cserháti Tibor , Oliviera José , Illés Tibor , Illés Zoltán
Published: June 2003

A three‐ways array data matrix consisting of the activity data of laccase enzyme has been evaluated by both principal component analyses (PCA) and Tucker3 model. Activity data have been determined in 28 culture media, at 6 sampling times and by four strains of Lentinus edodes. PCA has been carried out three times one of the factors being always the variables and the other two factors being the observations. The dimensionality of the matrices of loadings calculated by PCAs and those of component matrices of Tucker3 model has been reduced to two by the nonlinear mapping technique. It has been found that the dimensionality of component matrices for Tucker3 model can be predicted from the results of PCAs. Linear regression analyses indicated that the distribution of the original data points on the two‐dimensional nonlinear maps considerably depends on the fact that the data have been calculated by PCA or by Tucker3 model.