bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the repassivation behavior of aluminum and aluminum alloy exposed to chromate solutions
Authors: Chidambaram Devicharan , Jaime Vasquez M. , Halada Gary P. , Clayton Clive R. 
Published: January 2003

AbstractThis study explores the repassivation ability of a scratch in a chromate conversion coating (CCC) on aluminum alloy, AA2024‐T3, and hence evaluates the theory of migration of hexavalent chromium ions from the protected surface of the aluminum alloy to the exposed surface. To confirm that protection was indeed restored by hexavalent chromium ions, the repassivation of a scratch on pure aluminum exposed to a dichromate solution was studied. This forms the simplest subsystem model of the CCC on the alloy in which the CCC is replaced by pure hexavalent chromium and alloy with pure aluminum. Open‐circuit potential measurements, synchrotron infrared microspectroscopy (SIRMS) and secondary ion mass spectroscopy (SIMS) have been used judiciously to evaluate the repassivation behavior. Results indicate that the dichromate ions have high mobility. The slow migration of Cr(VI) ions from the protected surface to the scratch is observed to result in repassivation, as seen from the steady increase in the potential in 0.05 M NaCl solution. The results obtained from SIMS and SIRMS confirm the migration of the oxyanions from the protected region to the metal surface exposed by the scratch. The SIRMS results indicate the formation of an Al(III)–Cr(VI) complex, proposed and shown to be formed in the pits. Copyright © 2003 John Wiley & Sons, Ltd.
Auger peak shape analysis of AlN film grown by ammonia plasma
Authors: Wang P. W. , Sui Shixian , Durrer W. G. , Craig J. H. 
Published: January 2003

AbstractAn AlN film was grown using ammonia plasma and characterized with Auger electron spectroscopy in depth profile mode using argon sputtering. After growth of AlN on a 6061 Al substrate in a plasma chamber, the sample was removed from the vacuum and transported to an ultrahigh vacuum surface analysis system. Detailed AES spectra of Al, O and N are presented as a function of sputtering time (depth). Relative concentration changes were observed for the KLL O and KLL N signals but there were no significant lineshape changes, however significant relative concentration and lineshape changes associated with the LVV Al signal were observed. Lineshape analysis indicates the presence of the following bonds: Al–O (56 eV), Al–N (59 eV) and Al–Al (68 eV). Copyright © 2003 John Wiley & Sons, Ltd.
Surface characterization of keratin fibres treated by water vapour plasma
Authors: Molina R. , Jovančić P. , Jocić D. , Bertran E. , Erra P. 
Published: January 2003

AbstractThe effect of water vapour plasma treatment on the shrinkage behaviour and chemical properties of the surface of keratin fibres was studied. The wettability and shrink resistance of wool were improved even at low plasma treatment times. The values of the advancing contact angles of keratin fibres treated with plasma provide evidence of the formation of hydrophilic groups in the wool surface. Analysis by XPS reveals that oxidation of the fatty acid monolayer (F‐layer) prevails over its removal in the early stages of plasma treatment. The increase in treatment time results in a progressive removal of the F‐layer. Copyright © 2003 John Wiley & Sons, Ltd.
Consequences of x‐ray absorption fine structure for quantitative core‐level photoelectron spectroscopy
Authors: Karolewski M. A. 
Published: January 2003

AbstractThe dependence of x‐ray absorption fine structure (XAFS) on the chemical environment implies a corresponding environmental dependence of photoionization cross‐sections. The practical consequences of the XAFS for quantitative core‐level photoelectron spectroscopy have been studied for a number of materials with the help of simulations based on the ab initio FEFF code. The XAFS effects are predicted to be significant only for photoelectron kinetic energies below 250–300 eV. These effects take the form of systematic sensitivity factor variations between different chemical structural environments (e.g. compound materials quantified with reference to elemental standards). Apart from a few exceptions (e.g. the 2p core levels of Zn, Ga, Ge and As in metallic environments), the XAFS should introduce no significant errors when conventional Mg Kα or Al Kα sources are used for excitation. For core‐level spectra excited with synchrotron radiation or He II radiation sources, the quantification errors can readily approach or exceed 10% at room temperature (and are expected to increase at lower temperatures). Copyright © 2003 John Wiley & Sons, Ltd.
Influence of target surface degradation on the properties of r.f. magnetron‐sputtered calcium phosphate coatings
Authors: Boyd A. , Akay M. , Meenan B. J. 
Published: January 2003

AbstractThis paper reports a detailed study of how repeated r.f. magnetron sputtering from a hydroxyapatite (HA) powder target affects the nature and reproducibility of a sequential series of thin‐film coatings deposited onto Ti6Al4V substrates. An evaluation of the effective lifespan of the HA sputter targets and the reproducibility of the calcium phosphate (CaP) coatings produced from them has been made from Fourier transform infrared spectroscopy, XPS and, as appropriate, atomic force microscopy and SEM/energy dispersive x‐ray analyses. The annulus region of the target surface, from which sputtering under r.f. magnetron conditions normally occurs, showed severe surface degradation after only one deposition run, as indicated by significant PO43− and OH− depletion. This deterioration continued after each subsequent deposition cycle but to a much lesser extent than that observed in the initial sputtering period.The layers produced from all of the sputter runs contained the expected Ca2+ and PO43− species characteristic of a CaP system but were OH− deficient in the as‐deposited state. However, the chemical and morphological properties of the coatings did not change significantly until after the third consecutive sputter cycle. Hence, these data indicate that, even though a significant level of degradation of the HA target occurs at the outset of the sputtering procedure, the general plasma conditions employed here have a dominant influence on the coating properties until a critical degradation condition is met. As such, the compacted HA powder targets of interest can have a life‐cycle greater than single usage without detriment to the chemistry and morphology of the coatings produced from them. Copyright © 2003 John Wiley & Sons, Ltd.
Pump–probe second harmonic generation study of ultrafast spin dynamics in semiconductor multilayers
Authors: Glinka Yu. D. , Shahbazyan T. V. , Perakis I. E. , Tolk N. H. , Liu X. , Sasaki Y. , Furdyna J. K. 
Published: January 2003

AbstractWe report the first application of pump–probe second harmonic generation (SHG) measurements to characterize optically induced magnetization in non‐magnetic multilayer semiconductors. In the experiment, spin‐polarized electrons are excited selectively by a pump beam in the GaAs layer of GaAs/GaSb/InAs structures. However, the resulting net magnetization manifests itself through the induced SHG probe signal from the GaSb/InAs interface, thus indicating a spin‐polarized electron transport across the heterostructure. We find that the magnetization dynamics are governed by an interplay between the spin density evolution at the interfaces and the spin relaxation. Copyright © 2003 John Wiley & Sons, Ltd.
Biomimetic materials with tailored surface micro‐architecture for prevention of marine biofouling
Authors: Jelvestam Maria , Edrud Susanna , Petronis Sarunas , Gatenholm Paul 
Published: January 2003

AbstractThe long‐term goal of this study has been to prepare materials with a designed surface micro‐architecture that is able to prevent marine fouling by barnacles. Rows of steep microstructures with an elevation of a few micrometres separated from each other by 60 µm were manufactured using a biomimetic approach based on crystallization of calcite on surfaces of chemically patterned templates with carboxylate functionality. Templates were produced by the microcontact printing process using microfabricated silicone stamps with a surface micro‐architecture that has been shown to prevent barnacle settling. Electron spectroscopy for chemical analysis (ESCA), secondary ion mass spectrometry (SIMS) imaging and observations of wetting behaviour were used to examine the surfaces. The templates were used to grow surface microstructures by controlled crystallization of calcium carbonate by immersion in calcium chloride solution. Crystals grow randomly on the acidic areas of surfaces with 60/40 µm lines, whereas they grow in a regular fashion on a surface stamped with tiny (3–6 µm) 16‐mercaptohexadecanoic acid lines. This study showed that it is possible to prepare stable surface microstructures of a size up to 50 µm in a regular arrangement of lines. Copyright © 2003 John Wiley & Sons, Ltd.
Analysis of the surface chemistry of oxidized polyethylene: comparison of XPS and ToF‐SIMS
Authors: Briggs D. , Brewis D. M. , Dahm R. H. , Fletcher I. W. 
Published: January 2003

AbstractA series of low‐density polyethylene (LDPE) surfaces, chemically modified using a number of oxidative techniques employed for adhesion enhancement (pretreatments), have been studied by time‐of‐flight (ToF) SIMS and XPS. The methods consisted of corona discharge, flame, electrochemical, chromic acid, acid dichromate and acid permanganate treatment. All except flame treatment were performed under mild and fairly severe conditions to yield a range of surface chemistries. The XPS analysis, using high energy resolution and a refined approach to C 1s curve‐fitting, provided some new insights into the quantitative assessment of the type and concentration of functional groups. Both positive and negative ion ToF‐SIMS spectra were obtained at high mass resolution. The oxygen‐containing fragments were identified by accurate mass analysis and subjected to a detailed comparison with the XPS results. No convincing relative intensity correlations could be identified that would allow particular secondary ion fragments to be associated strongly with particular functional groups (in this multi‐functional surface situation). Inorganic residues resulting from wet chemical treatments were also investigated and here the two techniques were found to be more complementary. Copyright © 2003 John Wiley & Sons, Ltd.
Ultrathin cobalt silicide film formation on Si(100)
Authors: Hwang I. Y. , Kim J. H. , Oh S. K. , Kang H. J. , Lee Y. S. 
Published: January 2003

AbstractThe interfacial reaction between ultrathin Co film and substrate Si(100) was studied by in situ XPS using monochromatized Al Kα. When the Co is deposited on Si(100) at room temperature, CoSi2 is formed during the initial stage of Co deposition and then metallic Co starts to grow sequentially. For 8 ML Co deposition on Si(100) the interfacial reaction layer is relatively thin compared with the pure Co overlayer, which is not involved in the interfacial reaction in depth. The Co layers change rapidly to CoSi layers after annealing at 270°C, and then CoSi2 layers form after annealing at 540°C for 2 min. The CoSi2 layers are changed to CoSi2 islands by post‐annealing at >650°C. Copyright © 2003 John Wiley & Sons, Ltd.
Enhancement of polymer hydrophobicity by SF6 plasma treatment and argon plasma immersion ion implantation
Authors: Rangel E. C. , Bento W. C. A. , Kayama M. E. , Schreiner W. H. , Cruz N. C. 
Published: January 2003

AbstractIn this study sulphur hexafluoride (SF6) plasmas and argon plasma immersion ion implantation (ArPIII) techniques have been applied to improve the hydrophobicity of poly(tetrafluoroethylene) (PTFE), polyurethane and silicone surfaces. As evaluated by water contact angle measurements, all the treatments resulted in a significant enhancement in the hydrophobicity of the polymers. However, exposure of the treated samples to air induced a strong variation in their hydrophobicity as a consequence of post‐plasma reactions between atmospheric species and remnant surface free radicals. X‐ray photoelectron spectroscopy results strongly suggest that for polyurethane and silicone the surface fluorination by SF6 plasmas and the creation of new carbon bonds and radicals are the main agents for hydrophobicity enhancement. The PTFE exposed to ArPIII revealed increases in the contact angles after exposure to air. A significant incorporation of oxygen and the formation of new carbon bonds were revealed by XPS measurements. Copyright © 2003 John Wiley & Sons, Ltd.
Adsorption of polyamides on SAMs: effect of SAM grafting density on polyamide morphology
Authors: Elzein Tamara , Brogly Maurice , Schultz Jacques 
Published: January 2003

AbstractIn this paper we focus on the understanding of the morphological behaviour of Polyamide 66 (PA66) in a constrained geometry generated by adsorption onto chemically controlled interfaces such as thiol self‐assembled monolayers (SAMs) grafted on gold substrates. The latter are prepared under different experimental conditions to illustrate the mechanism of PA–SAM interaction. The crystalline morphology of polyamide nanofilms, analysed by atomic force microscopy, was found to be dependent directly on the surface chemistry that is controlled by the thiol functionality (e.g. NH2‐ and COOH‐ terminated thiols) and by the density and the structural organization of the grafts. These two parameters depend on the immersion times of the gold substrate in the thiol solutions. Furthermore, a direct correlation is evidenced between the polyamide morphology in thin films and its crystalline amount, as calculated by polarization–modulation infrared reflection–absorption spectroscopy. Quantitative results propose an interfacial interaction mechanism between the polyamide chains and the surface grafts, and give information about the SAM formation kinetics and its organization during the grafting process. Copyright © 2003 John Wiley & Sons, Ltd.
Construction of database of effective energy‐loss functions
Authors: Nagatomi T. , Takai Y. , Crist B. V. , Goto K. , Shimizu R. 
Published: January 2003

AbstractEffective energy‐loss functions for Al, Cu, Ag and Au were derived from the reflection electron energy‐loss spectroscopy (REELS) spectra for 1 keV electrons using extended Landau theory. Features of the obtained effective energy‐loss functions are close to those of optical surface energy‐loss functions, revealing the significant contribution of the low energy loss below a few tens of electron‐volts in the REELS spectrum for Cu, Ag and Au. The REELS spectra were reproduced using the newly derived effective energy‐loss functions, leading to the confirmation that this type of database of the effective energy‐loss function is very useful not only for more comprehensive understanding of the measured spectrum of surface electron spectroscopies but also for practical background subtraction in surface electron spectroscopy. Copyright © 2003 John Wiley & Sons, Ltd.
Influence of carbon on the interfacial contact angle between alumina and liquid aluminum
Authors: Rocha‐Rangel Enrique , Becher Paul F. , Lara‐Curzio Edgar 
Published: January 2003

AbstractThe wetting of alumina by pure liquid aluminum was investigated over the temperature range 900–1300°C by the sessile drop method under a dynamic vacuum of 10−4–10−5 Pa. When the substrate is carbon coated, the terminal contact angle is reduced to 40° at 1300°C for times longer than 4500 s. In the absence of carbon, the final angle is 82° for the same conditions. Reactive wetting is suggested by the observation of undercutting of the substrate and ridge formation at the leading edge of the liquid aluminum in all carbon‐coated samples. Based on energy considerations, the following is among the thermodynamically favorable reactions: 4Al + 3C → Al4C3. Possible mechanisms for the observed carbon‐enhanced wettability in the system are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Extracapsular Hematoma of the Parathyroid Glands
Authors: Chaffanjon Philippe C.J. , Chavanis Nicolas , Chabre Olivier , Brichon Pierre Yves 
Published: January 2003

The objective of this study was to standardize surgical treatment of cervicothoracic hematoma due to parathyroid gland rupture. Only 19 such hematomas have been reported in the literature, and there is no consensus about the best time to operate or the surgical approach. We have now treated four new cases of extensive hematoma from the time of the initial bleeding except in the case of severe hemodynamic or respiratory troubles or nerve compression. Two of the patients were operated on after a minimal 3 months delay, with perfect results. The other two were operated on during the first month with great technical difficulty and incomplete results. In one case the gland was not excised, but parathyroid apoplexy afforded a spontaneous remission, although the hyperparathyroidism recurred 7 years later. We concluded that, first, if there are no severe compressive or hemodynamic symptoms, the surgical treatment must be performed more than 3 months after the bleeding, as the dissection then is as simple as any well ordered surgery. In case of an extensive hematoma accompanied by shock or compression, we propose simple emergency drainage, with reoperation 3 months later. Second, parathyroid apoplexy sometimes offers spontaneous remission of primary hyperparathyroidism, although late recurrence is always possible and surgical treatment then cannot be avoided.
Intrapulmonary Expression of Scavenger Receptor and CD14 and Their Relation to Local Inflammatory Responses to Endotoxemia in Mice
Authors: Jiang Jian‐Xin , Chen Yong‐Hua , Xie Guo‐Qi , Ji Shan‐He , Liu Da‐Wei , Qiu Jun , Zhu Pei‐Fang , Wang Zheng‐Guo 
Published: January 2003

This study was first designed to investigate systematically the kinetics of surface expression of scavenger receptors (SRs) and CD14 on alveolar macrophages in vivo and in vitro and their relation with local pro‐ and antiinflammatory responses in endotoxemia. The expression of SR and CD14 in lungs was down‐ and up‐regulated, respectively, in the presence of endotoxemia, which might be due to decreased expression of SR and increased expression of CD14 on the surface of the resident macrophages. Down‐regulation of SRs on alveolar macrophages not only induces decreased defensive function of the macrophages, it also enhances lipopolysaccharide (LPS)‐induced activation of alveolar macrophages possibly through increasing LPS binding to CD14. Although CD14 is a key receptor responsible for LPS to activate macrophages, both phospholipase C and anti‐CD14 antibody can completely inhibit activation of alveolar macrophages initiated by only LPS 1 ng/ml, as determined by tumor necrosis factor‐{alpha} (TNF{alpha}) production, but it does not significantly change TNF{alpha} release upon cell stimulation by LPS 10 {mu}g/ml. There was an intrinsic relation of enhanced intrapulmonary pro‐ and antiinflammatory responses with changes in SR and CD14 expression, which suggests that the down‐regulation of SR and up‐regulation of CD14 might be an important mechanism for the lung to change from a defense organ to an effector organ during sepsis.
Effect of treatment for Chlamydia trachomatis during pregnancy
Authors: Rastogi S , Das B , Salhan S , Mittal A 
Published: February 2003

AbstractObjectives: To screen and treat chlamydial infection in pregnant women in order to assess the effects of therapeutic intervention on the outcome of Chlamydia trachomatis‐infected pregnancy. Methods: Enrolled in the study were 350 women in the first to third trimesters of pregnancy. Endocervical swabs were collected for C. trachomatis diagnosis by DFA and PCR. A few STD infections, viz.: Neisseria gonorrhoeae, Candida spp., bacterial vaginosis, Trichomonas vaginalis and Treponema pallidum were ruled out. After excluding 22 patients infected with other sexually transmitted infections, a cohort of 328 pregnant women comprised the study population. Anti‐chlamydial treatment (viz.: oral therapy with erythromycin stearate, 500 mg 4 times daily for 7 days) was given to 17 women (group I) and their partners. Fifteen patients of group I were retested by DFA and PCR assay for C. trachomatis infection 2 weeks following therapy. Other Chlamydia‐positive patients (n=42) who were lost to follow‐up were classified as untreated positive cases (group II) while group III included C. trachomatis negative cases (n=269). Data on obstetric outcome were recorded in a total of 164 cases. Statistical comparison of the data were done using the χ2‐test and means were compared using Student's t‐test. Results: Among the 350 pregnant women enrolled initially for the study, C. trachomatis positivity was found to be 18.8% (n=66) in the endocervix by DFA and PCR assay. Co‐infection with Candida spp., bacterial vaginosis, T. vaginalis and T. pallidum was 2.0%, 1.7%, 1.7% and 0.5%, respectively. None of the pregnant women was infected with N. gonorrhoeae. Pregnant women at an increased risk of chlamydial infection included those who had multiple births and were in second trimester of pregnancy. Fifteen patients of group I became Chlamydia‐negative following treatment. Data on obstetric outcome were recorded in 11, 26 and 127 patients of groups I, II and III, respectively. The mean duration of gestation for premature deliveries was found to be significantly higher in group I in comparison with group II [35.5 vs. 33.1 weeks (P<0.05)], thereby showing an improved effect of treatment on pregnancy outcome. The mean of low birth weight births was higher in group I compared with group II (2200.0 vs. 2113.3 g), however, this was statistically non‐significant. Stillbirths were significantly higher among group II in comparison with group III [11.5% vs. 4.7% (χ2=1.79; P<0.5)]. No stillbirths were recorded in patients who had taken anti‐chlamydial treatment. Conclusions: Our findings suggest that routine screening and treatment of C. trachomatis infection in pregnant women, especially those in high risk groups, should be mandatory to reduce the adverse effects on obstetric outcome.
FIGO Save the Mothers Initiative: the Central America and USA collaboration
Authors: Curet L.B. , Foster‐Rosales A. , Hale R. , Kestler E. , Medina C. , Altamirano L. , Reyes C. , Jarquin D. 
Published: February 2003

AbstractThe American College of Obstetricians and Gynecologists (ACOG) and the Central American Federation of Associations and Societies of Obstetrics and Gynecology (FECASOG), as a part of the FIGO Save the Mothers Initiative, undertook a pilot project to improve provision of basic emergency obstetric care in selected departments in four Central American countries. This article describes the process of the development and implementation of the project. Preliminary results suggest that the capacity to provide this care has been improved by the training of healthcare personnel.