bluuebunny/crossref_metadata_2025_split huggingface dataset:
Overlap integrals with respect to quantum numbers over Slater‐type orbitals via the Fourier‐transform method
Authors: Öztekin Emin 
Published: August 2004

AbstractA unified analytical treatment of overlap integrals over Slater‐type orbitals, using the Fourier transform method, is presented. Our approach leads to considerable simplification of the derivation of analytical representations for the overlap integrals over Slater type orbitals. In this approach, the representations of overlap integrals with both the same and different screening parameters have been obtained with the help of the Rayleigh expansion of a plane wave in terms of spherical Bessel functions and spherical harmonics. Analytical expressions obtained by this method have been expressed in terms of Gaunt coefficients, which are the product of spherical harmonics, Gegenbauer, and binomial coefficients. These overlap integrals have also been calculated with respect to the differences in n1 − l1 and n2 − l2 numbers that are even or odd. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Comparison of laser‐induced dissociation and high‐energy collision‐induced dissociation using matrix‐assisted laser desorption/ionization tandem time‐of‐flight (MALDI‐TOF/TOF) for peptide and protein identification
Authors: Macht Marcus , Asperger Arndt , Deininger Sören‐Oliver 
Published: August 2004

AbstractThe fragmentation of peptides under laser‐induced dissociation (LID) as well as high‐energy collision‐induced dissociation (CID) conditions has been investigated. The effect of the different fragmentation mechanisms on the formation of specific fragment ion types and the usability of the resulting spectra, e.g. for high‐throughput protein identification, has been evaluated. Also, basic investigations on the influence of the matrix, as well as laser fluence, on the fragment ion formation and the consequences in the spectral appearance are discussed.The preconditions for obtaining ‘pure’ CID spectra on matrix‐assisted laser desorption/ionization tandem time‐of‐flight (MALDI‐TOF/TOF) instruments are evaluated and discussed as well as the differences between LID and CID in the resulting fragment ion types. While containing a wealth of information due to additional fragment ions in comparison with LID, CID spectra are significantly more complex than LID spectra and, due to different fragmentation patterns, the CID spectra are of limited use for protein identification, even under optimized parameter settings, due to significantly lower scores for the individual spectra. Conditions for optimal results regarding protein identification using MALDI‐TOF/TOF instruments have been evaluated. For database searches using tandem mass spectrometric data, the use of LID as fragmentation technique in combination with parameter settings supporting the use of internal fragment ions turned out to yield the optimal results. Copyright © 2004 John Wiley & Sons, Ltd.
Formation of c1 fragment ions in collision‐induced dissociation of glutamine‐containing peptide ions: a tip for de novo sequencing
Authors: Lee Young Jin , Lee Young Moo 
Published: August 2004

AbstractA c1 ion was observed with significant yield in the tandem mass (MS/MS) spectra of peptide ions containing glutamine as the second amino acid residue from the N‐terminus. The c1 fragment was generated independently of the N‐terminal residue of the peptide, but its abundance was strongly dependent on the side‐chain identity. This ion is not a common fragmentation product in low‐energy collision‐induced dissociation of peptide ions, but it assists in identification of the first two amino acid residues, often difficult due to a low or absent signal from the heaviest y ion. A consecutive fragmentation mechanism is proposed, involving a b2 ion with a six‐membered ring as an intermediate, to explain the exceptional stability of the c1 fragment ion. The utility of this information is discussed, especially in de novo sequencing of peptide ions. Copyright © 2004 John Wiley & Sons, Ltd.
A dynamic model to predict responses of millets (Echinochloa sp.) to different hydrologic conditions for the Illinois floodplain–River
Authors: Ahn Changwoo , Sparks Richard E. , White David C. 
Published: August 2004

AbstractMillets grow on floodplain mud flats exposed when seasonal floods recede, and the seeds of this plant are an important food source for waterfowl during their spring and autumn migrations in the Mississippi Flyway. Productivity of millets along the Illinois River has declined because of unnaturally frequent floods that inundate the mud flats and drown the plants during the summer growing season. These small floods are caused by operation of the navigation dams on the main channel and by alterations of the floodplain and tributary watersheds and channels. Predictive models are needed to evaluate the most cost‐effective combination of approaches for restoring plant productivity. We developed a moist‐soil plant model that simulates millet growth on 1 m2 in response to daily water levels during the summer growing season. The model responds to daily water depth, flood timing (within the growing season), and flood duration, and was qualitatively verified using historical (1938–1959) water levels and plant coverage for three areas along the Illinois River. In the absence of untimely floods, the model predicts net above‐ground primary productivity of ∼500 g m−2 yr−1 and plant heights of up to 130 cm by the end of the growing season. As expected, growth declines with decreasing land elevation or with more frequent flooding (or a shorter duration of the dry period) at the same elevation. A dry period of >85 days is required to achieve at least 50% of maximum production during the growing season, which is somewhat longer than the 70‐day recommendation based on reported field observations. The model predictions of plant success or failure agree with historical observations, indicating that water regime is a major factor limiting plant success. Copyright © 2004 John Wiley & Sons, Ltd.
Bond strength and microstructure investigation on Al2O3/Al/Al2O3 joints
Authors: Ksiazek M. , Sobczak N. , Mikulowski B. , Radziwill W. , Winiarski B. 
Published: August 2004

AbstractThe subject of this work was the study of the mechanical strength, fracture character and microstructure of the Al2O3/Al/Al2O3 joints, formed by liquid‐state bonding of alumina using Al interlayers of two thicknesses (30 and 300 µm) at a temperature of 973 K under a vacuum of 0.2 mPa for 5 min. The bend strength of the joints was measured by a four‐point bending test at room temperature. Scanning electron microscopy was applied for detailed characterization of the interface structure and failure character on fractured joint surfaces. An analysis of results has shown that the decrease in the Al layer thickness leads to stronger Al2O3/Al/Al2O3 joints accompanied with the change of failure character. Copyright © 2004 John Wiley & Sons, Ltd.
Study of the effect of different aluminium surface pretreatments on the deposition of thin non‐functional silane coatings
Authors: Franquet A. , Terryn H. , Vereecken J. 
Published: August 2004

AbstractThis paper focuses on the effect of aluminium surface pretreatment on the formation of thin non‐functional silane films. Three pretreatments were used to prepare the aluminium surface before the deposition of silane films. The generated surfaces were characterized before and after the silane film deposition by infrared spectroscopic ellipsometry (IRSE) and by the combination of SEM, AES and spectroscopic ellipsometry (SE), respectively. It is demonstrated that the amounts of hydroxyl groups at the aluminium surface provided by the different pretreatments strongly influence the initiation and the formation of the silane films. Copyright © 2004 John Wiley & Sons, Ltd.
Enhancement of the durability of a polyamide coating: incorporation of an aminosilane into the powder formulation
Authors: Guichenuy Marianne , Watts John F. , Abel Marie‐Laure , Brown Andrew M. , Audenaert Marc , Amouroux Nicolas 
Published: August 2004

AbstractPolymer‐based coatings are widely used to protect steel from corrosion. A high level of adhesion between the coating and the steel substrate is essential if good corrosion protection is to be achieved. In the current work we explore the use of a silane adhesion promoter added to the powder stock prior to coating.A study has been undertaken on a polyamide 11 based powder coating on a steel substrate. Powders have been prepared, based on the reference product with addition of APS ((3‐aminopropyl) triethoxysilane, NH2(CH2)3Si(OCH2CH3)3) at different concentrations.The extent of delamination after salt‐spray testing has been documented and, for all coatings which incorporated the aminosilane, is reduced. Characteristic features of the delamination process have been obtained by AES. The enhanced durability is shown to result from the segregation of a layer of the organosilane to the interfacial region. Using a microtome taper sectioning method, a profile of the aminosilane within the thickness of the coating has been obtained. The bond between aminosilane and steel is probably covalent in nature as indicated by the presence of a specific ion FeOSi+ observed by high‐mass resolution ToF‐SIMS. Thus, the effect is similar to that achieved by the deposition of a discrete silane layer prior to coating application. Copyright © 2004 John Wiley & Sons, Ltd.
Surface modification of cycloolefinic copolymers for optimization of the adhesion to metals
Authors: Nikolova D. , Dayss E. , Leps G. , Wutzler A. 
Published: August 2004

AbstractLow‐pressure microwave plasma has been used to incorporate new functionalities onto the surface of cyclic olefin copolymers (COC). The main goal of the plasma treatment was to hydrophilize the COC's surface in order to enhance its adhesion to metals. The effect of two plasma parameters (treatment time and type of plasma gas) on the adhesion properties has been investigated. In order to investigate the opportunity for optimization of the adhesive strength in the COC–metal composite, an adhesion‐promoting layer of acrylic acid (AA), or inorganic SiO2, has been deposited. Copyright © 2004 John Wiley & Sons, Ltd.
The influence of surface roughness on the adhesion force
Authors: Meine K. , Kloß K. , Schneider T. , Spaltmann D. 
Published: August 2004

AbstractAdhesion measurements are presented which were carried out with an atomic force microscope between polymer balls attached to a cantilever and a silicon wafer under ultra high vacuum conditions. In using a silicon surface with a defined structure a correlation between adhesion force and contact area was found. This correlation could partly be explained by the Johnson–Kendall–Roberts model, if a change of the surface energy is assumed as a result of the structuring. For a constant geometric contact area an additional structuring leads to a decrease of the adhesion force. Copyright © 2004 John Wiley & Sons, Ltd.
Subcellular imaging of cell cultures and tissue for boron localization with laser‐SNMS
Authors: Arlinghaus H. F. , Fartmann M. , Kriegeskotte C. , Dambach S. , Wittig A. , Sauerwein W. , Lipinsky D. 
Published: August 2004

AbstractNon‐resonant laser secondary neutral mass spectrometry (NR‐laser‐SNMS) has been used for examining human melanoma cells grown in cell cultures and human glioblastoma xenografts grown in NMRI nude mice. Cells were incubated and mice were treated with boron‐containing drugs. Ion‐induced electron images were used to identify individual cells. Elemental and molecular images were obtained from the cancer cells with very high sensitivity and subcellular resolution. The measurement of the K/Na ratio demonstrated that for both cell cultures and tissue materials the preparation techniques used were appropriate for preserving the chemical and structural integrity of the living cell. The boron images show intra‐ and extracellular boron signals with different intensities. Molecular images show distinct features partly correlated with the cell structure. Copyright © 2004 John Wiley & Sons, Ltd.
Visualization of a plasma‐generated chemical micro‐pattern on polystyrene by XPS
Authors: Schröder K. , Babucke G. , Ohl A. 
Published: August 2004

AbstractChemical microstructures on polymer surfaces are of increasing interest for biological applications. Here, the potential of high‐resolution XPS (spatially as well as energetically) was investigated for characterization of these patterns. Chemical modifications obtained on non‐patterned samples were compared to chemical contrasts inside the 30–200 µm wide patterns on polystyrene (PS).Chemical contrasts in micro‐patterns down to 30 µm could be verified by small‐spot XPS and imaging XPS. While features with typical dimensions of some hundred micrometres were reproduced with high contrasts and a chemical composition comparable to non‐patterned samples, blurred information was found for spectroscopy as well as imaging of micro‐patterns with typical dimensions less than 100 µm. Copyright © 2004 John Wiley & Sons, Ltd.
On surface distributions in natural cellulosic fibres
Authors: Johansson Leena‐Sisko , Campbell Joseph , Koljonen Krista , Kleen Marjatta , Buchert Johanna 
Published: August 2004

AbstractIn x‐ray photoelectron spectroscopy (XPS), knowledge of elemental depth distributions within the first 10 nm is often essential. However, none of the conventional XPS methods can reliably discern, for example, a thin overlayer from clusters on rough surfaces. Therefore, reliable experimental data on the actual distributions of lignin and extractives on the fibre surfaces is needed, although there are numerous XPS studies on cellulosic fibres and paper.We have studied surface distributions of organic compounds on natural cellulosic fibre materials (cotton, flax and softwood pulps) with XPS, using a novel approach introduced by Tougaard. We were able to model the surface composition of rough fibre surfaces via simple spectral analysis of the O 1s signal. The simple spectral background analyses used show that in the case of cotton and flax, the non‐cellulosic compounds cover the cellulosic fibre surface much more effectively than in softwood pulps, in spite of the smaller amount of non‐cellulosic material present. Copyright © 2004 John Wiley & Sons, Ltd.
ToF‐SIMS and laser‐SNMS analysis of apatite formation in extracellular protein matrix of osteoblasts in vitro
Authors: Dambach S. , Fartmann M. , Kriegeskotte C. , Brüning C. , Hellweg S. , Wiesmann H. P. , Lipinsky D. , Arlinghaus H. F. 
Published: August 2004

AbstractWe have applied laser secondary neutral mass spectrometry (laser‐SNMS) for examining different states of biomineralization in vitro. Additionally, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) was used to analyse fibronectin and collagen type I, the main matrix proteins involved in the mineralization process, in a model system.Primary osteoblast‐like cells derived from bovine metacarpals were cultured for 5 weeks on clean smooth silicon substrates. For mass spectrometric investigations, cells and newly‐formed minerals were cryofixed, freeze‐fractured, and freeze‐dried.The results indicate that extracellular enrichment of potassium typically occurs in the vicinity of single osteoblasts during the initial stages of mineralization. This interaction of potassium with matrix macromolecules may prevent uncontrolled apatite nucleation and control the transformation of the matrix into a nucleating system. Thus, monovalent cations seem to be involved in the regulation of mineral nucleation of the extracellular matrix. From the data obtained it can be concluded that ToF‐SIMS and laser‐SNMS are well suited for imaging trace element and molecule concentrations in biological samples as well as for identifying molecular fragments characteristic of matrix proteins. Copyright © 2004 John Wiley & Sons, Ltd.
Surface modification of polymeric films and membranes to achieve antibacterial properties
Authors: Cen L. , Neoh K. G. , Ying L. , Kang E. T. 
Published: August 2004

AbstractA surface modification technique was developed to impart antibacterial properties on polymeric films and membranes. Poly(ethylene terephthalate) (PET) films and poly(vinylidene fluoride) (PVDF) membranes were first graft‐copolymerized with 4‐vinylpyridine (4VP) and subsequently quaternized with hexylbromide. Both these substrates can be functionalized with varying amounts of pyridinium groups and these groups possess antibacterial properties as shown by assay using waterborne Escherichia coli. The stability of the antibacterial properties of the N‐hexyl pyridinium groups on the PET film was investigated and the same efficiency in killing the E. coli on contact was observed for the modified film after a 60 day storage in air. Thus, the present surface modification method offers the advantages of simplicity in processing, good control over the surface concentration of pyridinium groups, long‐term stability as well as wide applicability. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization of metal decorated protein templates by scanning electron/scanning force microscopy and microanalysis
Authors: Habicht Wilhelm , Behrens Silke , Wu Jin , Unger Eberhard , Dinjus Eckhard 
Published: August 2004

AbstractHighly ordered protein assemblies have been used as bio‐organic templates either for the alignment of metallic nanoparticles or for the generation of continuous nanowires. A defined metallization of microtubules (MTs) is potentially interesting for the fabrication of conductive nanowires. Characterization of the in vitro assembled biomolecular templates and the subsequent metal deposition was performed by electron microscopic methods (SEM, TEM) and by scanning force microscopy (SFM). The SEM was equipped additionally with a special device to obtain transmission‐type images (STEM‐in‐SEM operation). Palladium particle deposition and also a continuous silver coverage of the protein templates was demonstrated. Copyright © 2004 John Wiley & Sons, Ltd.
XPS and FT‐IR spectroscopy study of albumin adsorption on the surface of a π‐conjugated polymer film
Authors: Iucci G. , Polzonetti G. , Infante G. , Rossi L. 
Published: August 2004

AbstractThe interaction between thin films of polyphenylacetylene (PPA) and bovine serum albumin (BSA) dissolved in phosphate buffer solution (PBS) was studied by x‐ray photoelectron spectroscopy (XPS) and Fourier‐transform infrared spectroscopy (FT‐IR) performed in reflectance mode. PPA is a semiconducting π‐conjugated polymer consisting of a polyene backbone with phenyl pending groups, that has been used in the preparation of humidity sensors; therefore, we have tried to pre‐test PPA films for possible applications as biosensors.Thin films of PPA were incubated in buffered albumin solution (BSA/PBS) for increasing exposure times (24–96 hours). BSA adsorption on the PPA film surface takes place as demonstrated by the appearance of the N 1s signal and by the modifications in the C 1s core‐level signal in the XPS spectra of the samples treated with albumin solution; time‐dependent adsorption is also observed. Phosphate salts are co‐adsorbed on the PPA surface upon treatment with BSA/PBS solution. Albumin adsorption on the PPA surface was confirmed by FT‐IR measurements. Copyright © 2004 John Wiley & Sons, Ltd.
Influence of polymer surface hydrophilicity on albumin adsorption
Authors: Henry M. , Bertrand P. 
Published: August 2004

AbstractX‐ray photoelectron spectroscopy (XPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) were used to characterize human serum albumin (HSA) adsorption on polycarbonate membranes: a native PC membrane (PC) and a hydrophilic treated one (PCOx/PVP). Principal component analysis was used to reveal the difference in the amount of HSA adsorbed on the two substrates. The treated membrane was found to have a lower affinity for albumin than the native one. Copyright © 2004 John Wiley & Sons, Ltd.
Ion‐beam treatment of PEO; towards a physically stabilized anti‐fouling film
Authors: Manso‐Silván M. , Valsesia A. , Gilliland D. , Ceccone G. , Rossi F. 
Published: August 2004

AbstractPolyethylene oxide (PEO), widely used in the biomedical field because of its anti‐fouling properties, has been deposited by spin coating and stabilized by modifying its molecular structure through ion‐beam treatments (IBT). The polymer films were exposed to different gas mixtures in order to observe the changes related to physical (Ar), soft chemical (Ar/N2) and strong chemical (Ar/O2) modification. The surfaces of the polymers were characterized after different modification times. The film composition analysis has been performed by correlating Fourier transform‐infrared spectra and x‐ray photoemission spectra. The characterization has been completed with a morphological evaluation by atomic force microscopy. Contact angle measurements were used to show the efficiency of the stabilizing treatment. By using physical masking during IBT, culturing bovine serum albumin and analysing the surface by time‐of‐flight secondary ion mass spectrometry, it has been shown that ion beam treatments are an effective way to produce PEO films that retain their anti‐fouling properties. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of the support on the surface composition of vanadium phosphate catalysts in the oxidative dehydrogenation of ethane
Authors: Casaletto M. P. , Lisi L. , Mattogno G. , Patrono P. , Ruoppolo G. 
Published: August 2004

AbstractVanadyl phosphate catalysts supported on different oxides (γ‐Al2O3, TiO2, SiO2) have been investigated by x‐ray photoelectron spectroscopy (XPS). The surface chemical composition has been studied as a function of the thermal treatment under oxidizing (calcination) or reaction conditions in the oxidative dehydrogenation of ethane. Dispersion of vanadyl phosphates on γ‐Al2O3 and TiO2 results in the formation of vanadium species in different oxidation states, i.e. V5+ phosphate, V5+ and V4+ oxide species, whose relative fraction depends both on the support and on the reaction temperature. A progressive reduction of vanadium species occurs in the samples as an effect of the temperature. Vanadyl phosphates exhibit a stronger interaction with the titania support, which undergoes surface modifications after impregnation, thermal treatments and catalysis runs. A noticeable interaction of the alumina support and a poor dispersion of the active phase on silica are also revealed by XPS. Copyright © 2004 John Wiley & Sons, Ltd.
The effect of platinum on the reducibility of Rh oxides on CeZr modified alumina supported automotive catalysts
Authors: Polvinen R. , Vippola M. , Valden M. , Lepistö T. , Suopanki A. , Härkönen M. 
Published: August 2004

AbstractThe reducibility of Rh oxide on Rh‐only and PtRh catalysts was investigated. The catalyst washcoats were composed of alumina modified by La and CeZr mixed oxide. The catalyst ageing was performed in air at 1000°C for 3 h. In order to study the synergistic effect of Pt and Rh on the reducibility of Rh oxide, the propensity of the noble metal oxides to reduction was investigated by exposing the fresh and aged catalysts to 400 mbar of H2 at 300°C. XPS was used to observe the changes in chemical state of the noble metals and TEM and XRD were employed to determine the catalyst composition and morphology. Differences were revealed in the behaviour of Rh‐only and PtRh catalysts in H2‐reduction. Rhodium supported on alumina‐containing washcoats without Pt was found to react with the support at elevated temperatures to form a reduction‐resistive oxide phase. On the PtRh bimetallic catalyst Rh was found to be partly reducible after air ageing and the Rh 3d transition emerged with an unusually low binding energy after H2‐reduction. PtRh alloy particles were also formed in air ageing. Copyright © 2004 John Wiley & Sons, Ltd.