bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous and Sensitive HPLC Determination of Mono‐ and Disaccharides, Uronic Acids, and Amino Sugars after Derivatization by Reductive Amination
Authors: Fischer Klaus , Wacht Marion , Meyer Axel
Published: October 2003

The reductive amination of low‐molecular‐weight saccharides, uronic acids, and amino sugars, followed by a separation of the derivates by means of ion‐pair chromatography or RP‐HPLC, offers an interesting alternative to HPAEC‐PAD for the environmental analysis of these compounds. Under this aspect various potential amination reagents, i.e., p‐amino‐benzoic acid (p‐AMBA), p‐AMBA propyl ester, 1‐aminopyrene, 2‐(2‐aminophenyl)indole, and 4‐aminoazobenzene, were tested with regard to the formation of derivates and to the chromatographic properties of the formed derivates.

p‐AMBA, p‐AMBA propyl ester and 4‐aminoazobenzene proved to be especially suited, because they facilitate the amination of all carbohydrate reference components together with a complete separation and sensible detection (detection limits < 0.5 mg/L) of the derivates. Mainly the following elution sequence was ascertained: amino sugars (hexosamines) / disaccharide(s) / monosaccharides (hexoses) / hexuronic acid(s) / N‐acetyl‐D‐glucosamine. Detection limits down to 0.1 μmol/L were realized using p‐AMBA as reagent, facilitating the determination of the target compounds in landfill leachates and lysimeter percolates. Applying the p‐AMBA propyl ester for derivatization, chromatographic interferences with weakly retained derivates and the coelution of the reagent with its galactosamine derivate can be avoided, since the ester elutes after its derivates unlike p‐AMBA itself.
Schwefel und Selen: Bedeutung der Oxidationsstufe für Struktur und Funktion von Proteinen
Authors: Jacob Claus , Giles Gregory I. , Giles Niroshini M. , Sies Helmut
Published: October 2003

Schwefel und Selen kommen in Proteinen als Bestandteile der Aminosäuren Cystein, Methionin, Selenocystein und Selenomethionin vor, deren Ausnahmestellung in neueren Arbeiten unterstrichen wird. Ihre Redoxeigenschaften unter physiologischen Bedingungen ermöglichen eine erstaunliche Vielfalt posttranslationaler Proteinmodifikationen, metallfreier Redoxreaktionen und ungewöhnlicher Chalkogenredoxzustände. Wie keine andere Aminosäure kann das “Redox‐Chamäleon” Cystein an so unterschiedlichen Redoxreaktionen wie Atom‐, Elektronen‐ und Hydridtransfer sowie Radikal‐ und Austauschreaktionen beteiligt sein. Es kommt im menschlichen Körper in zahlreichen Oxidationsstufen vor, von denen jede mit charakteristischen chemischen (z. B. Redox‐ und Metallbindungs‐) und biologischen Eigenschaften verknüpft ist. Durch die Position des Selens im Periodensystem der Elemente zwischen Metallen und Nichtmetallen werden Selenoproteine zu idealen Katalysatoren einer Vielzahl biologischer Redoxumwandlungen, sodass die chalkogenhaltigen Aminosäuren Cystein, Methionin, Selenocystein und Selenomethionin und ihre einzigartige Biochemie Gegenstand eines vielversprechenden Forschungsgebietes sind.
Recent Advances in the Activation of Boron and Silicon Reagents for Stereocontrolled Allylation Reactions
Authors: Kennedy Jason W. J. , Hall Dennis G.
Published: October 2003

Despite the popularity of boron and silicon allylation reagents in stereocontrolled synthesis, they suffer from a number of inherent limitations that have slowed down their development as synthetic tools for nucleophilic additions to carbonyl compounds and imine derivatives. These limitations are the low reactivity and diastereoselectivity of allyl trialkylsilane reagents, and the lack of catalytic systems for the activation and substoichiometric control of enantioselectivity in the additions of allyl boron reagents. To develop more efficient and general methods for the control of absolute stereochemistry in the resulting homoallylic alcohols, new approaches aimed at solving the problem of activation of allylic boron and silicon reagents are needed. This Minireview describes a number of recent approaches that have been devised to address this problem.
Chronic upper extremity pain and co‐occurring symptoms in a general population
Authors: Gummesson Christina , Atroshi Isam , Ekdahl Charlotte , Johnsson Ragnar , Ornstein Ewald
Published: October 2003

Objective

To estimate the prevalence of self reported chronic upper extremity pain associated with physical impairment in a general population, and its co‐occurrence with chronic upper extremity numbness or tingling and chronic pain at other locations.

Methods

A general health questionnaire was mailed to 3,000 persons (age 25–74 years) who were randomly selected from a general population register.

Results

The response rate was 83%. The prevalence of chronic upper extremity pain associated with physical impairment was 20.8% (95% confidence interval [95% CI] 19.2–22.5), and that of co‐occurring numbness or tingling was 6.7% (95% CI 5.7–7.7). Among the responders with chronic upper extremity pain associated with physical impairment, 84% reported more than 1 painful area.

Conclusion

Chronic upper extremity pain associated with physical impairment and co‐occurring chronic upper extremity numbness or tingling were common in the general population. The presence of more than 1 location for pain in the upper extremity as well as in other parts of the body was frequent.
Leadership Blues
Authors: March James G. , Weiner Stephen S.
Published: October 2003

All leaders will face difficult circumstances. These will frequently have little or nothing to do with anything the leader created or can influence. Administrators of community colleges, particularly presidents, are commonly neither prepared nor trained to face a tougher, and perhaps meaner, job than in earlier years; those who would lead should understand and be prepared.
Role of Universities in Leadership Development
Authors: Duvall Betty
Published: October 2003

University doctoral programs play a significant role in preparing community college leaders. Criteria of successful programs are discussed, along with how they should relate to community college professionals entering the program.
Administration 101: Evaluation of a Professional Development Program
Authors: Chiriboga Cristina
Published: October 2003

In this formative evaluation, the author examines a leadership development program provided by a professional association and includes implications for other programs.
Mass Transfer in a Flat Gas/Liquid Interface using non‐Newtonian Media
Authors: Gómez‐Díaz D. , Navaza J.M.
Published: October 2003

Gas/liquid mass transfer has been investigated using a stirred vessel gas/liquid contactor using non‐Newtonian media and carbon dioxide as absorbent and gas phase, respectively. The volumetric mass transfer coefficients at different operational variables have been determined. Non‐Newtonian media (liquid phase) were prepared as aqueous solutions of sodium carboxymethyl cellulose salt. The influence of the rheological properties, polymer concentration, stirring rate, and gas flow rate on mass transfer was studied for these liquid phases. Kinematic viscosity and density experimental data were used to calculate the average molecular weight corresponding to the polymer employed. The Ostwald model has been used to fit the rheological behavior of aqueous solutions of the polymer employed as absorbent phase. Reasonably good agreement was found between the predictions of the proposed models and the experimental data of mass transfer coefficients.
Determination of Local Gas Hold‐up and Volumetric Mass Transfer Co‐efficient in a Bubble Column by Means of an Ultrasonic Method and Neural Network
Authors: Supardan M.D. , Maezawa A. , Uchida S.
Published: October 2003

Previous work has proven the capability of ultrasonic and neural network methods to predict the hydrodynamic behavior of a bubble column. There is still a problem in applying this method to the case where the mass and the heat transfer occur in a bubble column. We present the implementation of a novel technique based on an ultrasonic and neural network, to simultaneously determine ϵG and kLa, in a 2‐D bubble column. Preliminary results showing the capability of the proposed method will be presented.
Flow Tube with Mobile Sampling Orifice: Compact Reaction System for Toxic and Corrosive Gases and Aerosols
Authors: Letzel T. , Schauer C. , Niessner R. , Pöschl U.
Published: October 2003

For aerosol process studies, different kinds of reaction vessels and measurement techniques are required depending on the types of gases, particles and interactions to be examined. In this work, a compact flow tube system for investigating the interaction of highly toxic and corrosive gases and aerosol particles under well‐defined and controlled conditions is presented. It allows to perform experiments with minimum space requirements under a fume hood, without the risk of exposing the operator to the investigated hazardous substances.
Synthesis and Supramolecular Properties of Trimethylene‐Bridged Clips
Authors: Klärner Frank‐Gerrit , Lobert Matthias , Naatz Ulf , Bandmann Heinz , Boese Roland
Published: October 2003

The novel trimethylene‐bridged clips 3 and 4 have been synthesized by using repetitive stereoselective Diels–Alder reactions of the benzo‐ and naphthobismethylenenorbornenes 8 and 19 as dienes and norbornadiene 9 as bisdienophile, and subsequent dehydrogenation of the primary cyclobisadducts 10 and 20 by using 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ). Clips 3 and 4 serve as receptors for a variety of electron‐deficient neutral and cationic aromatic substrates, comparable to the molecular tweezers 1 and 2. The thermodynamic parameters of the complex formation, Ka and ΔG, were determined by 1H NMR titration experiments and, in the case of the highly stable complex TCNB 32@4, by the use of isothermal titration microcalorimetry. The finding that clip 4 forms more stable complexes than 3 can be explained by the larger van der Waals contact surfaces of the naphthalene sidewalls in 4 compared to the corresponding benzene systems in 3. In the complexes with 4 as receptor, the plane of each aromatic substrate molecule is calculated to be oriented almost parallel to the naphthalene sidewalls. However, in the complexes of tweezers 2, the substrate is usually oriented parallel to the central naphthalene spacer unit. Due to the more open topology of 4, most complexes were calculated to consist of two or more equilibrating noncovalent conformers.
The Open‐Chain Trioxide CF3OC(O)OOOC(O)OCF3
Authors: von Ahsen Stefan , García Plácido , Willner Helge , Burgos Paci Maximiliano , Argüello Gustavo A.
Published: October 2003

The open‐chain trioxide CF3OC(O)OOOC(O)OCF3 is synthesised by a photochemical reaction of CF3C(O)OC(O)CF3, CO and O2 under a low‐pressure mercury lamp at −40 °C. The isolated trioxide is a colourless solid at −40 °C and is characterised by IR, Raman, UV and NMR spectroscopy. The compound is thermally stable up to −30 °C and decomposes with a half‐life of 1 min at room temperature. Between −15 and +14 °C the activation energy for the dissociation is 86.5 kJ mol−1 (20.7 kcal mol−1). Quantum chemical calculations have been performed to support the vibrational assignment and to discuss the existence of rotamers.
Photochromism of Diarylethenes Linked by Hydrogen Bonds in the Single‐Crystalline Phase
Authors: Yamamoto Satoshi , Matsuda Kenji , Irie Masahiro
Published: October 2003

Photochromic diarylethenes, which bear carboxyl groups at the ortho, meta, or para positions of both terminal phenyl groups, have been synthesized. The diarylethenes adopt linear chain structures as a result of hydrogen bonding in the crystalline phase, and the crystals exhibit photochromic properties. The absorption maximum of the photogenerated closed‐ring isomer of the para‐substituted derivative shows an 80 nm bathochromic shift in comparison with that of the ortho‐substituted derivative. The maximum of the closed‐ring isomer of the meta‐substituted derivative is located in between those of the para‐ and ortho‐substituted derivatives. The shifts can be attributed to the differences in conformation among the derivatives, arising from the restrictions imposed by the hydrogen‐bonded chains.
Synthetic and Structural Studies of Cobalt–Pivalate Complexes
Authors: Aromí Guillem , Batsanov Andrei S. , Christian Paul , Helliwell Madeleine , Parkin Andrew , Parsons Simon , Smith Andrew A. , Timco Grigore A. , Winpenny Richard E. P.
Published: October 2003

The synthesis and characterisation of a range of cobalt pivalate cage complexes are reported. The cages include: a dinuclear CoII complex; an oxo‐centred CoIII triangle; tetranuclear CoII heterocubanes and butterflies; tetranuclear heterovalent cobalt butterflies and hexanuclear edge‐sharing bitetrahedra; heterovalent penta‐, hexa‐ and hepta‐nuclear cages based on {M4O4} heterocubane cores; and a tetradecanuclear cage based on heterocubanes sharing edges and vertices. Spectroscopic studies suggest that some of these cores are retained in solution, but that only in the CoIII triangle is the structure including ligands retained. A scheme is proposed to account for the many structures observed, which may be applicable to other polymetallic cage complexes.
Modulating Charge‐Transfer Interactions in Topologically Different Porphyrin–C60 Dyads
Authors: Guldi Dirk M. , Hirsch Andreas , Scheloske Michael , Dietel Elke , Troisi Alessandro , Zerbetto Francesco , Prato Maurizio
Published: October 2003

Control over the interchromophore separation, their angular relationship, and the spatial overlap of their electronic clouds in several ZnP–C60 dyads (ZnP=zinc porphyrin) is used to modulate the rates of intramolecular electron transfer. For the first time, a detailed analysis of the charge transfer absorption and emission spectra, time‐dependent spectroscopic measurements, and molecular dynamics simulations prove quantitatively that the same two moieties can produce widely different electron‐transfer regimes. This investigation also shows that the combination of ZnP and C60 consistently produces charge recombination in the inverted Marcus region, with reorganization energies that are remarkably low, regardless of the solvent polarity. The time constants of electron transfer range from the μs to the ps regime, the electronic couplings from a few tens to several hundreds of cm−1, and the reorganization energies remain below 0.54 eV and can be as low as 0.16 eV.
Remarkable Reactions of Cyclooctatetraene Diiron‐Bridging Carbyne Complexes with Amino and Amido Compounds: Nucleophilic Addition to and Breaking of the Cyclooctatetraene Ring
Authors: Zhang Shu , Xu Qiang , Sun Jie , Chen Jiabi
Published: October 2003

The reactions of the cationic, diiron‐bridging carbyne complexes [Fe2(μ‐CAr)(CO)4(η8‐C8H8)]BF4 (1, Ar=C6H5; 2, Ar=p‐CH3C6H4; 3, Ar=p‐CF3C6H4) with LiN(C6H5)2 in THF at low temperature gave novel N‐nucleophilic‐addition products, namely, the neutral, diiron‐bridging carbyne complexes [Fe2(μ‐CAr)(CO)4(η7‐C8H8N(C6H5)2)] (4, Ar=C6H5; 5, Ar=p‐CH3C6H4; 6, Ar=p‐CF3C6H4)). Cationic bridging carbyne complexes 1–3 react with (C2H5)2NH, (iC3H7)2NH, and (C6H11)2NH under the same conditions with ring cleavage of the COT ligand to produce the novel diiron‐bridging carbene inner salts [Fe2{μ‐C(Ar)C8H8NR2}(CO)4] (7, Ar=C6H5, R=C2H5; 8, Ar=p‐CH3C6H4, R=C2H5; 9, Ar=p‐CF3C6H4, R=C2H5; 10, Ar=C6H5, R=iC3H7; 11, Ar=p‐CH3C6H4, R=iC3H7; 12, Ar=p‐CF3C6H4, R=iC3H7; 13, Ar=C6H5, R=C6H11; 14, Ar=p‐CH3C6H4, R=C6H11, 15, Ar=p‐CF3C6H4, R=C6H11). Piperidine reacts similarly with cationic carbyne complex 3 to afford the corresponding bridging carbene inner salt [Fe2{μ‐C(Ar)C8H8N(CH2)5}(CO)4] (16). Compound 9 was transformed into a new diiron‐bridging carbene inner salt 17, the trans isomer of 9, by heating in benzene. Unexpectedly, the reaction of C6H5NH2 with 2 gave a novel COT iron–carbene complex [Fe2{C(C6H4CH3‐p)NHC6H5}(μ‐CO)(CO)3(η8‐C8H8)] (18). However, the analogous reactions of 2‐naphthylamine with 2 and of p‐CF3C6H4NH2 with 3 produce novel chelated iron–carbene complexes [Fe2{C(C6H4CH3‐p)NC10H7}(CO)4(η2:η3:η2‐C8H9)] (19) and [Fe2{C(C6H4CF3‐p)NC6H4CF3‐p}(CO)4(η2:η3:η2‐C8H9)] (20), respectively. Compound 18 can also be transformed into the analogous chelated iron–carbene complex [Fe2{C(C6H4CH3‐p)NC6H5}(CO)4(η2:η3:η2‐C8H9)] (21). The structures of complexes 6, 9, 15, 17, 18, and 21 have been established by X‐ray diffraction studies.
Unexpected Reaction Pathways in the Reaction of Alkoxyalkynylchromium(0) Carbenes with Aromatic Dinucleophiles
Authors: Sierra Miguel A. , Mancheño María J. , del Amo Juan C. , Fernández Israel , Gómez‐Gallego Mar
Published: October 2003

Thermal‐ or SiO2‐induced reactions of the Michael adducts of 1,2‐aromatic dinucleophiles and alkynylchromium(0) carbene complexes, compounds 7–10, form different products in good yields depending on the nature of the aromatic dinucleophile used. Thus, 1,2‐diaminobenzene derivatives 7 and 8 rearrange to pentacarbonylchromium(0) isocyanide complexes 11, 12, 14, and 15 in a process that occurs through bicyclic intermediates 24. Adducts 9 derived from o‐aminophenol give 2,3‐dihydro‐1,5‐benzoxazepine derivatives 17 by intramolecular 1,2‐addition, followed by protonation at the chromium center and reductive elimination. In contrast, base‐promoted addition of the phenolic hydroxy group in compound 9 a affords 3‐ethoxy‐5‐phenyl‐5,6‐dihydro‐2H‐1,6‐benzoxazocin‐2‐one (18), together with the expected adduct 17 a. Compound 18 is formed by a nucleophilic addition to a CO ligand in a preformed carbene complex. This is a new example of the rare attack of a nucleophile on a CO ligand in a Fischer carbene complex. Adducts 10 form seven‐membered‐ring carbene complexes 19 and 20 by intramolecular aminolysis. In contrast, reaction of alkynyl carbene complexes with 1,8‐diaminonaphthalene under very mild conditions leads to 2‐substituted perimidines 33 together with the corresponding ethoxymethylmetal carbene complex 32 through an unprecedented fragmentation process in a formal retro‐Aumann reaction.
Systematic Construction of a Monotetrahydrofuran‐Ring Library in Annonaceous Acetogenins by Asymmetric Alkynylation and Stereodivergent Tetrahydrofuran‐Ring Formation
Authors: Kojima Naoto , Maezaki Naoyoshi , Tominaga Hiroaki , Asai Mikito , Yanai Minori , Tanaka Tetsuaki
Published: October 2003

All eight diastereoisomers of the monotetrahydrofuran‐ring cores of annonaceous acetogenins have been synthesized through utilization of asymmetric alkynylation and stereodivergent one‐pot tetrahydrofuran‐ring formation. In all cases, the asymmetric alkynylation proceeded with very high diastereoselectivity to give eight kinds of optically pure tetrahydrofuran core from a common α‐oxyaldehyde. We also describe a comparison of the 1H NMR, 13C NMR, and CD spectral data of the eight isomers and give full details of the tetrahydrofuran‐ring construction including a model study of asymmetric alkynylation.
Cover Picture: Aromaticity and Electron Affinity of Carbok‐[3]radialenes, k=0, 1, 2 (Chem. Eur. J. 20/2003)
Authors: Lepetit Christine , Brøndsted Nielsen Mogens , Diederich François , Chauvin Remi
Published: October 2003

The cover picture shows the doubly charged (q=−2) buta‐1,3‐diynediyl expanded [3]radialene. The question whether aromaticity enhancement a possible driving force for the facile reduction of some expanded [3]radialenes has been explored. The theoretical study on a series of [3]radialenes with endocyclic and/or peripheral carbo‐meric expansion leads to a generalization of the simple 4n+2 πz Hückel rule to such “electronic roundabouts” with three possible “exits”. Thus, the doubly charged (q=−2) buta‐1,3‐diynediyl expanded [3]radialene shown contains 14 πz electrons in the cross‐conjugated ring and exhibits according to the calculations both magnetic and geometrical aromaticity. For more details see the article by R. Chauvin et al. on p. 5056 ff.
Pseudopotential theory of a partially ionized hydrogen plasma
Authors: Arkhipov Yu.V. , Baimbetov F.B. , Davletov A.E.
Published: October 2003

In the framework of the BBGKY hierarchy the main features of interparticle interactions in a partially ionized hydrogen plasma are extensively studied. The theory developed is quite analogous to the Debye‐Hückel approximation of a fully ionized plasma. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Static and dynamic properties of 2‐dimensional strongly coupled Yukawa liquids
Authors: Donkó Z. , Hartmann P. , Kalman G. J. , Rosenberg M.
Published: October 2003

Static and dynamical properties of strongly coupled Yukawa liquids are investigated. The particles are either (i) situated within an ideal 2‐dimensional plane or (ii) are confined by an external parabolic potential to form a quasi‐2‐dimensional configuration. The static simulations (yielding pair correlation functions and correlation energies) and dynamical simulations (yielding spectra of density and current fluctuations) are carried out for a wide range of coupling (Γ) and screening (κ) parameters. The dispersion relations show good agreement with the predictions of the QLCA theory. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Plasma phase transition in hydrogen and electron‐hole plasmas
Authors: Filinov V. , Bonitz M. , Levashov P. , Fortov V. , Ebeling W. , Schlanges M.
Published: October 2003

The plasma phase transition in dense hydrogen and in electron‐hole plasmas is investigated by direct path integral Monte Carlo simulations. Hydrogen results for the internal energy at T = 10, 000 K show a deep minimum and strong fluctuations around the density n = 1023 cm−3 indicating the existence of a phase transition. To verify this explanation, the analogous phenomenon is studied for an electron‐hole plasma in Germanium. The calculated phase boundary of the electron‐hole liquid is found to agree reasonably well with the available experimental data. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fluid metals in the liquid‐vapour critical region
Authors: Hensel F. , Pilgrim W.‐C.
Published: October 2003

Experimental results in the liquid vapour critical region of metals show that the metal‐nonmetal transition noticeably influences, the electronic, thermodynamic, structural, dynamic and interfacial features of fluid metals. The main emphasis of the paper is on the intimate interplay between the changes in interparticle forces and the changes in the electronic structure associated with the pressure ionization. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Equation of state for dense plasmas
Authors: Kuhlbrodt S. , Juranek H. , Schwarz V. , Redmer R.
Published: October 2003

The composition and equation of state of dense fluids and plasmas is calculated within the chemical picture. While dissociation is important for molecular fluids such as hydrogen, the excitation of higher ionization stages is relevant for e. g. noble gases and metal plasmas. Results for the Hugoniot curves of hydrogen‐helium mixtures which are relevant for astrophysical applications are shown. The composition of beryllium plasma at solid statelike densities and at temperatures of several eV is determined and compared with new experimental results. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fokker‐Planck equation with velocity‐dependent coefficients: Application to dusty plasmas and active particles
Authors: Trigger S.A. , Ebeling W. , Ignatov A.M. , Tkachenko I.M.
Published: October 2003

Self‐consistent and universal description of friction and diffusion for Brownian particles in such various systems as dusty plasma and active particles (e.g., cells in biological systems) is presented. Generalized friction function is determined to describe the friction force itself as well as a drag force in the case of non‐zero driven ion velocity in plasmas. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamic response of two‐component model plasmas
Authors: Zwicknagel G. , Pschiwul Th.
Published: October 2003

The dynamic structure factor of a two‐component model plasma, where the Coulomb interaction is regularized at short distances, is investigated in molecular dynamics simulation studies. Special attention is paid to the dependency of the dynamic response on a variation of the used effective interaction and a test of the accuracy of the predictions made by diverse theoretical treatments. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Complete maternal deprivation affects social, but not spatial, learning in adult rats
Authors: Lévy F. , Melo A. I. , Galef B. G. , Madden M. , Fleming A. S.
Published: October 2003

The effects of maternal deprivation on learning of social and spatial tasks were investigated in female adult rats. Pups were reared artificially and received “lickinglike” tactile stimulation (AR animals) or were reared with their mothers (MR animals). In adulthood, subjects were tested on paradigms of spatial learning and on paradigms involving learning of social cues. Results showed that maternal deprivation did not affect performance on spatial learning, but it did impair performance on the three social learning tasks. The AR animals made no distinction between a new and a previously presented juvenile conspecific. AR animals also responded less rapidly than MR animals at test for maternal behavior 2 weeks after a postpartum experience with pups. Finally, AR animals did not develop a preference for a food previously eaten by a familiar conspecific whereas MR animals did. This study indicates that animals reared without mother and siblings show no deficits in spatial tasks while showing consistent deficits in learning involving social interactions. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 177–191, 2003.
Arousal, but not nursing, is necessary to elicit a decreased fear reaction toward humans in rabbit (Oryctolagus cuniculus) pups
Authors: Pongrácz Péter , Altbäcker Vilmos
Published: October 2003

Rabbits that are handled at the time of feeding during the first week postpartum show reduced fear of humans later in their lives as compared to unhandled controls. Effective handling has been shown to be confined to a sensitive period. Our study aimed to investigate if feeding itself (provided by a second doe, 6 hr after the standard nursing time) affects the levels of fear of humans later in life. Our results showed that (a) the prenursing state of excitement is only characteristic of the standard nursing and is not elicited by a second feeding 6 hr past the usual nursing time, repeated daily across the first week postpartum; and (b) handling linked to a second feeding 6 hr after the standard nursing does not reduce fear responses toward humans at weaning. We conclude that the aroused state, per se, is essential for the reduction of a rabbit's fear response toward humans provoked by early handling. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 192–199, 2003.
Retrieval difficulty and retention of reactivated memories over the first year of life
Authors: Hildreth Karen , Hill Debra
Published: October 2003

A newly acquired memory is remembered longer when its retrieval is more difficult (i.e., when the time since the last retrieval is longer). In two experiments using an operant conditioning task with 198 infants between 3 and 12 months of age, we presently asked if a reactivated memory also is remembered longer when its retrieval is more difficult. During their first year, infants remember a memory reactivated 1 week after forgetting and the newly acquired memory equally as long. After determining the upper limit (UL) of reactivation at all ages (Experiment 1), we reactivated the memory near the UL and then measured its subsequent persistence (Experiment 2). We found that increasing the training‐reactivation interval enhanced retention at 6 months only. These data reveal that increasing retrieval difficulty affects infants' retention of newly acquired and reactivated memories differently. More generally, memory reactivation seems to disproportionately benefit retention in younger infants. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 216–229, 2003.
Application of a novel polypropylene to the insulation of an electric power cable
Authors: Yoshino Katsumi , Demura Tsuyoshi , Kawahigashi Masaki , Miyashita Yoshitsugu , Kurahashi Kiyoshi , Matsuda Yoshiji
Published: October 2003

Cross‐linked polyethylene (XLPE) has been widely adopted as insulating material for high‐voltage power cables up to 500 kV. Further improvement of electrical and thermal properties on insulating material is required in order to increase cable operation efficiency. Therefore, the development of novel insulating material possessing high thermal properties will be necessary.

Recent progress of catalysis technology contributes to obtain new polymeric materials which may be applied to electrical insulation. The authors investigated the basic properties of newly developed stereoregular syndiotactic polypropylene (s‐PP) which is synthesized with homogeneous metallocene catalyst. Though recycling of cross‐linked polymers such as conventionally used XLPE may be difficult because of their poor heat deformation, the s‐PP which is not cross‐linked must be suitable for recycling.

A series of experiments on its physical and electrical properties gave the following results.

s‐PP has sufficient flexibility compared with isotactic polypropylene (i‐PP ).

Both AC and lightning impulse breakdown strength of s‐PP in spite of no cross‐linking are superior to those of XLPE in the temperature range from 25 to 90 °C.

Degradation by copper of s‐PP is less than that of i‐PP.

s‐PP/VLDPE blend shows sufficient brittleness temperature for use.

These results suggested that s‐PP should serve as insulating material for power cables at higher‐temperature operation. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 18–26, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002//eej.10210
Countermeasures for controlling lightning‐caused overvoltage on indoor wiring with communication line
Authors: Nakada Kazuo , Sugimoto Hitoshi , Shimada Seiichi , Asaoka Yoshinobu , Asakawa Akira
Published: October 2003

Overvoltage generated by lightning is a threat to indoor electrical equipment in our information‐oriented and computerized society. Countermeasures for preventing overvoltage on indoor wiring are demanded. Therefore, we have investigated the effectiveness of some countermeasures, such as low‐voltage arresters, communication line arresters, SPDs, and a common grounding wire, for reducing the overvoltage on indoor wiring with a communication line. In particular, we have studied the effect of the combination of these countermeasures and their layout on controlling the overvoltage, using a full‐scale test distribution line with a customer's facility. The main results are as follows:

A common grounding wire installed along the low‐voltage indoor wiring is more effective for reducing the overvoltage on the indoor wiring with a communication line than is one installed under the floor, when the arresters are installed at the panel board.

Combination of an SPD and other countermeasures, such as low‐voltage arresters and a common grounding wire, is effective for controlling the overvoltage on the indoor wiring, and the effectiveness of these countermeasures for preventing damage of electrical equipment has been verified by an experiment using actual electrical equipment. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 37–45, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10223
Environmental assessment of the EU Structural Funds: the German Objective 1 regional development plan and Berlin operational programme
Authors: Fischer Thomas B.
Published: October 2003

Whilst the assessment of environmental impacts should form an integral part of EU Structural Fund documentation, to date the extent to which this has happened has largely remained unclear. Addressing this shortcoming, the paper looks at recent practice in the German Objective 1 areas. In this context, the regional development plan of the ‘new’ German Länder and the operational programme for the Eastern part of Berlin are analysed, using the EU Structural Fund SEA (strategic environmental assessment) Handbook, the ‘SEA Directive’ (2001/42/EC) and SEA ‘good practice’ criteria, as proposed in the professional literature. It is found that whilst some SEA aspects are considered in current practice, there is scope for improvement, particularly in terms of an early integration of the assessment in the plan making process, a better consideration of alternatives, a wider consultation process, the preparation of a separate EA report and more transparent plan approval. Copyright © 2003 John Wiley & Sons, Ltd and ERP Environment.
Environmentally friendly policy schemes as models for the introduction and use of agri‐environmental indicators in Greece
Authors: Vlahos George , Beopoulos Nikos
Published: October 2003

A considerable number of indicators are already in use for the assessment of the agricultural sector's environmental performance as well as for the evaluation of agri‐environmental policies.

Given the existing difficulties in testing such indicators, we have used for this purpose – with fairly good results – the documentation (at the farm level) of two environmentally friendly policy schemes, on organic agriculture and on integrated management, for assessment of the set of agri‐environmental indicators, described in two relevant communications from the Commission.

Indicators describing pressures and state of the environment susceptible to estimation differ significantly from one scheme to another. However, available documentation, if complemented, makes plausible an environmental diagnosis of farms as well as monitoring and evaluation of environmental performance of these schemes. Copyright © 2003 John Wiley & Sons, Ltd and ERP Environment.
Study of the Complexation, Adsorption and Electrode Reaction Mechanisms of Chromium(VI) and (III) with DTPA Under Adsorptive Stripping Voltammetric Conditions
Authors: Sander Sylvia , Navrátil Tomáš , Novotný Ladislav
Published: October 2003

The complexation of Cr(III) and Cr(VI) with diethylenetriaminepentaacetic acid (DTPA), the redox behavior of these complexes and their adsorption on the mercury electrode surface were investigated by a combination of electrochemical techniques and UV/vis spectroscopy. A homogenous two‐step reaction was observed when mixing Cr(III), present as hexaquo complex, with DTPA. The first reaction product, the electroactive 1 : 1 complex, turns into an electroinactive form in the second step. The results indicate that the second reaction product is presumably a 1 : 2 Cr(III)/DTPA complex. The electroreduction of the DTPA‐Cr(III) complex to Cr(II) was found to be diffusion rather than adsorption controlled.The Cr(III) ion, generated in‐situ from Cr(VI) at the mercury electrode at about −50 mV (vs. Ag|AgCl) (3 mol L−1KCl), was found to form instantly an electroactive and adsorbable complex with DTPA. By means of electrocapillary measurements its surface activity was shown to be 30 times higher than that of the complex built by homogenous reaction of DTPA with the hydrated Cr(III). Both components, DTPA and the in‐situ built complex Cr(III) ion were found to adsorb on the mercury electrode.The effect of nitrate, used as catalytic oxidant in the voltammetric determination method, on the complexation reaction and on the adsorption processes was found to be negligible.The proposed complex structures and an overall reaction scheme are shown.
Caffeine Extraction with a Karr Reciprocating Plate Column
Authors: Hu X. , Wang X. , Yang H.
Published: October 2003

A Karr reciprocating plate column was used in extracting caffeine from the methylation mother solution of a caffeine synthesis plant with chloroform as the extractant. Pilot tests were carried out in a 38 mm diameter column to determine holdup, flooding and mass transfer at various reciprocation velocities. Results show that the holdup in the presence of mass transfer is higher than that in the absence of mass transfer, and the height of the equivalent theoretical stage (HETS) was 0.57 m for a 99.9 % recovery at the optimum reciprocation velocity. The Karr empirical correlation for scale‐up was used to predict the column height in the design of the industrial process. A 0.4 m and a 0.6 m diameter column were used to treat 2.5 m3/h and 6.0 m3/h methylation mother solution, and the corresponding HETSs were 1.42 m and 1.53 m for a 99.9 % recovery, respectively. The axial dispersion coefficients of the dispersed phase were estimated for the 0.4 m and the 0.6 m diameter columns. For a better recovery the ratio of the axial dispersion coefficient of the dispersed phase to that of the continuous phase was about 2.7–3.0.
Pretreatment and Hydrolysis of Brewer's Spent Grains
Authors: Macheiner D. , Adamitsch B.F. , Karner F. , Hampel W.A.
Published: October 2003

Brewer's spent grains (BSG), the voluminous residue after mashing, contains on dry weight basis about 40–50 % polysaccharides. For the recovery of soluble carbohydrates from BSG different physical, thermal and enzymatic treatments were used to solubilize the polysaccharides in BSG. Heating by microwave radiation to 160 °C in the presence of 0.1 M HCl released 35 % of the material in the form of reducing sugar, indicating that about 80 % of the polysaccharides were hydrolyzed. Nevertheless, 0.1 M acetic acid will even solubilize 30 % of the material as oligosaccharides on a prolonged incubation when pretreating the spent grains by extrusion cooking. A combination of the enzymes Ceremix Plus MG and CelluPract AL 70 achieved an almost 25 % release of saccharides after 4 hrs of incubation at 50 °C. A combination of extrusion cooking and enzymatic hydrolysis seems to be a very promising procedure.
Constitution, microstructure, mechanical properties, and performance of magnetron‐sputtered carbon films with additions of silicon
Authors: Bauer C. , Leiste H. , Stüber M. , Ulrich S. , Holleck H.
Published: October 2003

Amorphous carbon films with additions of silicon were deposited by non‐reactive magnetron sputtering on WC‐Co hard metal and on silicon substrates. The targets were hot‐pressed, homogenous mixtures of graphite and silicon carbide powder. Additional argon ion bombardment of the growing film was applied by a substrate bias varied between 0V and ‐800 V. The deposited amorphous carbon films with two different silicon contents (5 at.% and 23 at.% respectively) were characterised with respect to their microstructure, density, thickness, residual stress, Vickers hardness, Young's modulus, critical load of failure, friction coefficient, and wear behaviour. The residual stress of the carbon films could be remarkably lowered by silicon additions (23 at.%). The hardness reached high values (2200 HV0.05) and the friction coefficient for unlubricated sliding friction against a steel (1.3505) counterpart was as low as 0.06.
Leistungsfähige PVD‐Wälzlagerbeschichtungen
Authors: Gold P. W. , Loos J. , Kuhn M.
Published: October 2003

Anhand von Axial‐Zylinderrollenlagern wurde systematisch untersucht, inwieweit PVD‐Schichten in der Lage sind, die Funktionen von EP/AW‐Schmierstoffadditiven zu übernehmen. Die Wälzlager wurden im starken Mischreibungsgebiet geprüft, um die Leistungsfähigkeit der Schichten möglichst schnell differenzieren zu können. Verschiedene Schichtsysteme wurden auf ihre Fähigkeit hin untersucht, einen unbeschichteten Gegenkörper zu schützen. Dazu wurden bei Wälzlagern lediglich die Lagerscheiben beschichtet, die Rollen blieben unbeschichtet. Dabei zeigten vier Me‐C:H‐Schichsysteme beste Verschleißschutzeigenschaften und kaum Oberflächenschädigungen. Der Übertrag von Schichtmaterial auf die unbeschichtete 100Cr6 Wälzkörperoberfläche konnte für den hervorragenden Verschleißschutz verantwortlich gemacht werden. Dazu wurden genauere Untersuchungen mit der ESMA Analyse (electron beam micro range analysis) bei ZrCg‐Schichten durchgeführt. Es konnte eine Triboschicht mit hohen Zirkon‐ und Sauerstoffanteilen nachgewiesen werden.
Metallurgical Aspects of Sliding Wear of fcc Materials for Medical Applications
Authors: Büscher R. , Fischer A.
Published: October 2003

Worn surfaces of biomedical fcc alloys X2CrNiMo18‐15‐3, CoCr29Mo6, X13CrMnMoN18‐14‐3 are generated by sliding wear in order to understand the mechanisms, which bring about small wear particles. Depending on the acting wear mechanisms the debris is produced by different sites of crack initiation and paths of crack propagation. Thus, the subsurface deformation mechanisms are investigated as well. This investigation revealed that the worn surfaces of all three materials consist of a nanocrystalline layer underneath which appearances of cyclic deformation are visible. With respect to the stacking fault energy X13CrMnMoN18‐14‐3 as well as the CoCr29Mo6 depict sliding bands, stacking faults, and strain induced ε‐martensite bringing about a sufficient support of the nanocrystalline layer. Thus, 80 to 500 nm fine globular and lamellar wear particles are just torn off this layer. In contrast to this, X2CrNiMo18‐15‐3 shows cell walls in distances of about 50 μm below the worn surfaces, which act as sites for crack initiation and propagation. The mean wear particles are about an order of magnitude bigger and range from 20 to 250 μm. Due to the fact that the nanocrystalline layer is not supported by the material underneath it has no distinct positive effect on the wear rate.
Electromagnetic effects on the friction and wear of solid‐solid interface
Authors: Bhushan B. , Ge S.
Published: October 2003

This paper presents the state‐of‐the‐art of recent investigations on the friction and wear behavior of some solid interfaces in a magnetic field or electric current environment. The tribometers used for study of electromagnetic effect on friction and wear are introduced. The experimental results of the variation of coefficient of friction and wear rate for magnetic and nonmagnetic materials and materials with varying electrical conductivities are summarized. It is found that both magnetic field and electric current have significant influence on the friction and wear of these materials. The magnetic and electrical properties of sliding couples control the friction and wear in response to applied magnetic field and electric current, respectively. Relevant mechanisms and observations are also reported in the paper.
Tribology of Ceramics and Hard Coatings
Authors: Kato K.
Published: October 2003

Because of the high hardness of ceramics and ceramic coatings, very smooth wear surfaces are generated in the run‐in process under certain frictional conditions. In vacuum, tribo‐assisted In coating gives friction coefficient in the range from 0.10 to 0.02 between Si3N4 pins and SUS440C steel disks. In water, friction coefficient in the range from 0.01 to 0.001 is generated between self‐mated Si3N4 and SiC in sliding. In N2 gas, friction coefficient in the range from 0.01 to 0.001 is generated between Si3N4 ball and CNx coating and between DLC coated ball and DLC coated disk. These low friction coefficients observed with ceramics and without oil are promising new tribo‐technologies for space and environment.
Microsurgical tracheotomy: A pediatric model in growing rats
Authors: Cecília Bochetti Manna Mônica , Frasson de Souza Montero Edna , Quintino de souza Leão Jovelino , Ferreira Novo Neil
Published: October 2003

Previous studies described controversial opinions about pediatric tracheotomy concerning type of tracheal incision and long‐term results, which remain as important research subjects. Experimental studies on rat tracheas are scarce, probably because of technical difficulties related to the structures' small dimensions. As many rat organ and system operative procedures were studied successfully by using microsurgical techniques, we decided to develop a pediatric tracheotomy model in growing rats which would permit long‐term studies. Forty‐four Wistar EPM‐1 growing rats weighing 86 g and aged 35 days were divided into three groups: submitted to longitudinal, transverse, and segment excision of the trachea. Under sterile technique and intramuscular anesthesia (ketamine/xylazine), the trachea was exposed and incised, according to group, and a hand‐made endotracheal cannula was inserted into the organ. This cannula was assembled using a segment of 1.5‐cm‐long 3 French silicone catheter passed through hexagonal‐shaped silicone screen. The tracheal cannula was removed after 7 days, when we evaluated body weight, secretions, and dehiscence. In conclusion, this microsurgical tracheotomy model in growing rats is feasible, allowing studies on long‐term repercussions of pediatric tracheotomy. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:530–534 2003
Morphological changes on small‐bowel fetal allografts in mice
Authors: Resende Vanessa Contato Lopes , Montero Edna Frasson De Souza , Leão Jovelino Quintino De Souza , Manna Mônica Cecília Bochetti , Koike Márcia Kiyomi , Pedrosa Marcelo Eduardo , Simões Manuel De Jesus
Published: October 2003

The aim of this study was to evaluate the early morphological development and acute rejection process in fetal intestine allografts. Grafts from C57BL/6 fetal intestines were implanted in an avascular form in BALB/C recipients. A syngeneic group of animals was used to compare the evolution. The allogeneic recipients were distributed in 6 groups, according to the day of sacrifice (3rd, 4th, 5th, 6th, 7th, and 10th postoperational day (POD)) and the control group on the 2nd, 5th, and 7th POD. These grafts were stained with hematoxylin and eosin for histological evaluation, in agreement with the classification of Auber et al. (Chirurgie 123:122–130, 1998). Data showed a progressive development of the graft until POD 5. On POD 3 and 4, a top grade of development and an initial rejection were observed. From POD 5–7 and on POD 10, the acute rejection reaction was more important than the development process. The higher level of rejection was observed on POD 10, and it was similar to the 7th POD. Our results showed good graft development until POD 5. After that, the acute rejection response impeded analysis of the development process.

O objetivo deste trabalho foi avaliar o desenvolvimento e o processo de rejeição aguda em aloenxertos de intestino fetal. Enxertos de intestino fetal de camundongos C57BL foram implantados de forma avascular. Os receptores foram distribuídos em 6 grupos, de acordo com o dia do sacrifício (3°, 4°, 5°, 6°, 7°, e 10°). Um grupo singênico foi feito para comparar a evolução. Os receptores alogênicos foram distribuídos em 6 grupos, de acordo com o dia do sacrifício (3°, 4°, 5°, 6°, 7°, e 10° PO) e o grupo controle foi separado em dias críticos para comparar a evolução: 2°, 5°, e 7° PO. Estes enxertos foram corados com hematoxilina e eosina para avaliação histológica, de acordo com a classificação de Auber et al. (Chirurgie 123:122–130, 1998). Os dados mostraram um desenvolvimento progressivo dos enxertos até o 5° PO. Observou‐se que no 3° e no 4° PO ocorreu um bom grau de desenvolvimento e um estágio inicial de rejeição. Do 5° ao 7° PO e no 10° PO, a reação de rejeição aguda foi mais importante do que o processo de desenvolvimento. O mais alto nível de rejeição foi observado no 10° PO, que foi semelhante ao do 7° PO. Nossos resultados mostraram um bom desenvolvimento do aloenxerto até o 5° PO, quando a resposta de rejeição aguda alterou a análise do processo de desenvolvimento. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:526–529 2003