bluuebunny/crossref_metadata_2025 huggingface dataset:
Auger backscattering factor at primary beam energies above 10 keV
Authors: Merlet C. , Jbara O. , Rondot S. , Cazaux J.
Published: December 2004

Taking into account the identity of the ionization function of electron probe microanalysis (EPMA) at the surface, Φ(0), and the Auger backscattering factor, r, new results and a compilation of published results are reported for the determination of r [or Φ(0)] obtained at normal incidence and at primary beam energies Eo above 10 keV.

The 79 experimental values thus obtained have been compared to the functional expressions proposed by Love and Scott, by Merlet [both for Φ(0)] and by Shimizu for r, leading to standard deviations of 11.3, 8.6 and 10.8%, respectively. At last, a deviation of 8.4% has been obtained when the experimental results are compared to a functional expression involving only the element of interest, Z1, at the surface and the electron backscattering factor, η, of the substrate. The advantage of this last approach is that it can be applied to correct automatically the backscattering effects of the Auger images and of the Auger depth profiles by the simultaneous measurement of η with a calibrated backscattered electron detector, but without the knowledge of the (changing) bulk composition.
Composition of oxides and nitrides from line shapes of metal core level x‐ray photoelectron spectra
Authors: Galán L. , Prieto P. , Morant C. , Soriano L. , Sanz J. M. , Elizalde E. , Rueda F.
Published: December 2004

A method is proposed which evaluates the averaged composition of a sample in terms of the centroid of the core level XP spectrum. The method is based on the basic principle of electron spectroscopy for chemical analysis, i.e. the additive property of the chemical shifts and their proportionality to the ligand co‐ordination. It allows one to calculate the averaged composition of compounds if the line shapes of spectra corresponding to stoichiometric samples (including the pure metal) are known and a few simple conditions are assumed. The main advantage of this method is that the composition can be obtained even if the individual contributions of the different oxidation states cannot be resolved or deconvoluted, so that no previous knowledge of the oxidation states or co‐ordination structure is necessary. This method of calculating the composition is illustrated by its application to ZrOx, HfOx, NbNx, TaNxOy and SiNxOy obtained by different methods. The results are then compared with those obtained from the usual XPS quantitative analysis, so that further insight to the sample near‐surface structure and composition can be gained by this combined study.
Quantitative analysis of reflection electron energy‐loss spectra
Authors: Yubero F. , Tougaard S.
Published: December 2004

It is shown that a quantitative description of the energy‐loss processes in a reflection electron energy‐loss spectroscopy (REELS) experiment cannot be obtained from a simple linear combination of pure bulk and pure surface components. A quantitative description can, however, be obtained within the dielectric response formalism for a more realistic model which takes into account the physical conditions in a REELS experiment.
Silicon ion bombardment of Sb/Si contacts
Authors: Malherbe J. B. , Friedland E. , Bredell L. J. , Fletcher M. , Weimer K. P.
Published: December 2004

Si+ bombardment of Sb/n‐Si Schottky contacts significantly affects the values of some Schottky parameters even at low does densities. The parameters considered are the ideality constant n, the saturation current density Is and the series resistance R. Before implantation these parameters exhibited large variations due to interface conditions. After implantation more uniform I–V characteristics were observed. Implantation led to higher values for the ideality constant and the series resistance and lower values for the saturation current. The ideality factor showed a decrease with increasing implantation dose. The saturation current and series resistance did not show any dose dependence. The compositional/structural properties of the contacts after ion bombardment are altered at high dose densities. For dose densities ϕ ≥ 5 × 1014 Si+ cm−2, α‐particle channelling showed the silicon substrate to be partly amorphized. This amorphization increased with increasing dose densities. AES and RBS measurements found no evidence of silicide formation. Only slight mixing was observed. Other experimental and theoretical studies either confirm our measurements or confirm the trend of our measurements.
Prolonged lifetime of electrochromism of amorphous WO3–TiO2 thin films
Authors: Hashimoto Satoshi , Matsuoka Hideki
Published: December 2004

The lifetime of the electrochromism of the WO3–TiO2 films prepared by vacuum evaporation is found to exceed that of WO3 films by a factor of five. X‐ray diffraction has revealed that the crystal structure of WO3–TiO2 films stays amorphous, while crystalline compounds are formed in amorphous WO3 films after colouring and bleaching. WO3–TiO2 films stay amorphous after they are annealed at 400°C, although WO3 films crystallize. SIMS and XPS analyses have revealed that half the amount of lithium injected during a colouring cycle is stored as OLi bonds in the bleached film. In WO3–TiO2 films the number of bonds such as WOH and WO in which lithium ions accumulate is reduced. We conclude that the lifetime of the electrochromism is prolonged for amorphous WO3–TiO2 films, because lithium does not accumulate and the WO3–TiO2 films stay amorphous.
The frontiers of surface structure analysis
Authors: Somorjai G. A.
Published: December 2004

Low‐energy electrons have been used predominantly to determine surface structure: low‐energy electron diffraction (LEED) surface crystallography to identify the location of surface atoms and molecules, their site symmetry, bond distances and bond angles; and high‐resolution electron energy‐loss spectroscopy (HREELS) to determine the vibrational spectra of atoms and molecules at surfaces. The key findings of research using LEED and HREELS will be discussed. The new directions of research using these two techniques for studies of disordered surface layers and more complex molecules will be reviewed.

Scanning tunneling microscopy (STM) and atomic force microscopy are new techniques under rapid development for surface structure determination. The combination of STM and LEED crystallography permits the quantitative validation of STM findings. Atomic spatial resolution uncovered several unexpected surface structures. The use of STM during high‐pressure catalytic reactions is at the frontier of surface structure studies.

Extended x‐ray adsorption fine structure (EXAFS) and photoelectron diffraction have been used to study the atomic structure and coordination of clusters. Laser sum frequency generation (SFG) is employed to obtain vibrational spectra of molecules at solid/liquid and solid/solid interfaces. These techniques expand the frontiers of surface structure analysis to new types of surface and interface systems.
Properties of surface‐modified alumina catalysts of COS synthesis
Authors: Auroux A. , Gervasini A. , Németh L. , Gáti G. , Pap I. S. , Mink G.
Published: December 2004

The surface electronic structure, the acid–base properties, the component adsorption and the catalytic activity of gamma alumina (CK‐300, Ketjen) modified with surface sodium as a donor‐type or iron as an acceptor‐type additive have been investigated. Alumina was loaded with 0.1 and 1 wt.% Na and Fe. The catalytic O/S exchange of CO2 and CS2 to form COS was applied as a model reaction, for which the kinetic parameters have also been determined. In the case of unloaded alumina and samples loaded with 0.1 wt.% Na and 0.1 or 1.0% Fe no characteristic differences in the shape and position of the O 1s and Al 2p lines were observed. However, 1.0 wt.% Na loading resulted in a broadening of the O 1s and Al 2p lines towards lower binding energies. Sodium, even in 1% monolayer coverage, and other donor‐type surface species, e.g. pre‐adsorbed NH3 or pyridine, exhibited a readily detectable promoter effect which could be characterized by increased surface basicity, increased CO2 and CS2 adsorption and better catalytic performance. In contrast, on catalysts loaded with Fe an increase in surface acidic sites, a loss of basic sites, decreased component adsorption and lower catalytic activity were observed.
Scattering in electron spectrometers, diagnosis and avoidance. II. Cylindrical mirror analysers
Authors: Seah M. P.
Published: December 2004

An analysis is made of the effects leading to an unwanted scattered background of electrons in cylindrical mirror analysers (CMAs). This work complements that given in Part I on concentric hemispherical analysers. It is shown that scattering from the middle region of the inner surface of the mirror electrode is significant but that the amount of scattering reaching the detector may be reduced by reducing the area of the output slit or by adding a deflection post filter to the optics as occurs in some commercial instruments. Internal scattering causes a higher background so that peak‐to‐background ratios are attenuated and transmission function calibrations involve a systematic error. Evidence for this error is a step in the calibration curves for I(E)/En(E) established earlier. The steps appearing in the curves for Cu and Ag reference samples give a direct measure of the scattering intensity. Calibration plots are established for this purpose. Results from previous interlaboratory comparisons are analysed showing that in commercial CMAs with large‐area energy selection slits the scattering may reach 35% of the copper true background at 950 eV, complicating the subsequent use of the data. Concentric hemispherical analysers and some commercial CMAs show very low scattering. In some CMAs the analogue detection systems cause a similar enhanced background in addition to scattering, boosting the above figure of 35% to 100%.
Determination of the distribution of chromium oxidation states in reduced Cr/Al2O3 catalysts from XPS by factor analysis and curve fitting
Authors: Scierka Stephanie J. , Proctor Andrew , Houalla Marwan , Fiedor Joseph N. , Hercules David M.
Published: December 2004

Principal component analysis (PCA) and target testing (TT) were performed on a series of reduced 2.5 wt.% Cr/Al2O3 catalysts to determine the number, positions, shapes and relative spectral compositions (i.e. Cr oxidation states) in Cr 2p spectra as monitored by ESCA. The results from PCA indicated the presence of only two abstract components. The abstract factors were transformed through iterative TT into real spectroscopic components that were attributed to Cr6+ and Cr3+. These factor analysis results were used in addition to non‐linear least‐squares curve fitting to provide a detailed description of changes in the Cr 2p envelope during reduction of the Cr/Al2O3 catalysts. Only two components were necessary to reproduce the original data.
Determination of attenuation lengths of photoelectrons in aluminium and aluminium oxide by angle‐dependent x‐ray photoelectron spectroscopy
Authors: Marcus P. , Hinnen C. , Olefjord I.
Published: December 2004

Angle‐dependent x‐ray photoelectron spectroscopy (AD‐XPS) measurements have been carried out on thin aluminium oxide layers formed on pure aluminium by oxidation in oxygen at 25°C and at 250°C. The amounts of oxygen of the oxide overlayers were measured by nuclear reaction analysis (NRA). The equipment thicknesses of the oxide layers were 14 Å and 21.5 Å for the oxides formed at 25°C and at 250°C, respectively. The AD‐XPS measurements were carried out in the range of take‐off angles 12–122°.

The signals emitted by Al3+ in the oxide and by Alm in the metal versus take‐off angle can be, within experimental error, fittex by an exponential function in the range of take‐off angles ∼30–120°. This confirms the applicability of an exponential law for the attenuation of photoelectrons for the studied system in the range of take‐off angles ∼30–120°. The AD‐XPS measurements were used to determine the attenuation lengths of the electrons emitted by aluminium (kinetic energy ∼1180 eV) in the oxide (λox) and in the metal (λm). The attenuation lengths derived from the experiments are: λox = 20 Å and λm = 18 Å. These values are lower than the theoretical inelastic mean free paths owing to the contribution of elastic scattering. For the lowest investigated take‐off angles (<30°) the measurements deviate from the exponential law. The deviation is attributed to the effects of elastic scattering and of the angle of acceptance of the photoelectrons.

As a complement to this work, an intercomparison of AD‐XPS measurements was performed in four laboratories on the two reference samples. In the range of take‐off angles 40–120°, the results can be fitted by the exponential law for the attenuation of the photoelectrons. However, differences of 10–20% were observed in the apparent overlayer thickness. Careful analysis of the data revealed that this was primarily caused by a systematic error introduced in the peak fitting when a symmetrical peak is used, instead of an asymmetrical peak, for the Alm signal.
Automatic removal of substrate backscattering effects in Auger imaging and spectroscopy
Authors: Barkshire I. R. , Prutton M. , Greenwood J. C. , El Gomati M. M.
Published: December 2004

The York multi‐spectral scanning Auger microscope has been used to investigate the correlations between Auger and backscattered electron images collected simultaneously from a electron spectrometer and the quadrants of a Sip‐n junction backscattered electron detector. Digital signal processing of the four backscattered electron signals allows the calculation of the Auger backscattering factor at each pixel position, the division of which into the Auger image allows the removal of contrast due to subsurface composition variations. The method, which allows the quantification of complicated heterogeneous samples, requires no fitting parameters or prior knowledge regarding the sample.
Comparison of validity and consistency of methods for quantitative XPS peak analysis
Authors: Tougaard S. , Jansson C.
Published: December 2004

In the present work, we have tested the consistency and validity of the Tougaard, Shirley and straight‐line methods for determination of peak intensities in XPS. Intensities were determined from essentially all photoelectron peaks (with Mg Kα and Al Kα radiation) from seven polycrystalline elemental solids (Co, Ni, Cu, Zn, Ag, Pt and Au) and for three sets of polycrystalline alloys (Cu0.75Au0.25, Cu0.5Au0.5, Cu0.25Au0.75, and Co0.75Ni0.25, Co0.5Ni0.5, Co0.45Ni0.55, Co0.25Ni0.75 and Cu0.55Ni0.44Mn0.01). For the three methods, the consistency of the peak intensity ratios determined under a variation of analyser settings was studied. The validity of the three methods was studied by comparison of peak intensity ratios to two sets of theoretical photoionization cross‐sections (due to Scofield and Band et al., respectively). The inelastic electron mean free paths were taken from theoretical tabulations when available or from analytical expressions (both due to Tanuma et al.).

The Tougaard method is found to be superior to the Shirley and straight‐line methods, both with respect to consistency and validity. For a selected set of peaks where the error on theory is minimal, the deviation from theory is 3% for the Tougaard method and 33–60% for the Shirley and straight‐line methods. Considering all XPS peaks from seven metals, the root‐mean‐square deviation from theory for the Tougaard method is found to be ∼11% for the ratios of peak intensities to a peak from the same solid and ∼14% for the ratios of peak intensities to the Au 4d peak intensity. These deviations fall within the expected accuracy of theory. The corresponding root‐mean‐square deviations from theory for the Shirley and straight‐line methods are found to be 35% and 25%, respectively. For alloys, the Tougaard method gives the most consistent description of the shake‐up electrons. For the Shirley and straight‐line methods applied to spin‐orbit doublet peaks, the accuracy is in general worse than the above.
Use of Zr− secondary ion energy distributions and factor analysis to construct chemical‐state depth profiles in SIMS
Authors: Splinter S. J. , van der Heide P. A. W. , Lin A. , McIntyre N. S.
Published: December 2004

Factor analysis (FA), the multivariate statistical technique, has been used to extract chemical bonding information from SIMS secondary ion energy distributions. The method is outlined in detail and shown to be capable of constructing quantitative profiles for the chemical states of zirconium present in ZrO2/Zr and ZrNx/Zr structures. In addition, a truncated data collection procedure wherein secondary ion intensity values are collected at a fixed number of emission energy values during the depth profile is outlined. This method, which enables data to be collected in a shorter time and from a smaller sample volume, is subsequently shown to yield reliable results, as confirmed by FA of Auger depth profiles on similar specimens.
Feasibility of quantitative analysis of metals and alloys by non‐resonant multiphoton ionization of sputtered neutral species
Authors: Scrivener E. , Wilson R. C. , Vickerman J. C.
Published: December 2004

A system for non‐resonant multiphoton ionization (NRMPI) of suttered neutral species has been developed. The instrumentation is based on a Kratos time‐of‐flight SIMS system with a dual‐stage ion reflectron. Ionization of sputtered neutral species is provided by a focused excimer laser beam of wavelength 193 nm.

Two basic operational procedures are defined that involve using either a continuous or pulsed primary ion beam for sputtering. The consequences of each mode on the resulting spectrum are considered. Characterization experiments are reported that show the effect of laser flux on the yields of elemental and molecular species, allowing conditions to be selected for subsequent experiments. The laser flux profiles demonstrate that saturation of the ionization process is easily achieved for most species studied. Relative sensitivity factors (RSFs) from elements in standard metal alloy samples are presented that suggest that some effect of matrix is present. However, reproducibility of RSFs between consecutive runs and between the pulsed and continuous modes of bombardment is very good (<10% and even <5% in some cases) for the majority of species. Values for the useful yield and detection limit in NRMPI and SIMS are compared.
Reactive ion sputter depth profiling of tantalum oxides: A comparative study using ToF‐SIMS and laser‐SNMS
Authors: Franzreb K. , Mathieu H. J. , Landolt D.
Published: December 2004

A time‐of‐flight (ToF) suptter depth profile analysis of standard 15 or 30 nm thick anodically formed Ta2O5 layers as well as of the naturally grown ∼2 nm thin oxide overlayer on metallic tantalum samples has been made using both the techniques of (positive and negative) secondary ion mass spectrometry (SIMS) and laser secondary neutral mass spectrometry (Laser‐SNMS). Specific emphasis of this comparative study is on the characterization of the performance of a state‐of‐the‐art ToF mass spectrometer with respect to sputter depth profiling. The prospects of SIMS and Laser‐SNMS for quantitative near‐surface analysis are addressed under special consideration of reactive (Cs+ or Ga+) ion beam sputtering applied in the present work.
Flexible poly (vinyl chloride) for long outdoor life
Authors: Orem John H. , Sears J. Kern
Published: December 2004

A review of the compounding requirements for producing flexible PVC with quite satisfactory outdoor life is presented. Testing criteria and the importance of incorporated additives of specific types are reviewed. Data on multi‐location outdoor weathering are shown. The prime importance of thickness and additive migration is proposed.
Aqueous finishing of vinyl film. I. Film properties
Authors: Cluthe C. E. , Goth S. , Martorano R.
Published: December 2004

Much of the coating industry has converted to water‐based substitutes in order to reduce organic emissions and to improve safety and employee environment. Recently the vinyl industry has shown an increased interest in alternative coating systems, particularly those based on water. Replacing solvent‐based gravure coatings with water‐borne materials presents many technical problems, not the least of which are maintenance of gravure printability and physical properties. Our studies on lower plasticizer containing grades of vinyl, primarily wallcovering, have culminated in the development of an aqueous model based on a room temperature crosslinking emulsion with resistance properties suitable for this application.
The effect of the plasticizer system on the processability of poly(vinyl chloride) compounds
Authors: Paul D. H.
Published: December 2004

To conserve energy and process time, the judicious use of benzyl phthalate as a partial substitution for dialkyl phthalate is suggested. Data is presented from laboratory and pilot plant tests. Confirmation and correlation with factory trials is shown.
The effect of formulation variables on smoke evolution of plasticized PVC during combustion
Authors: Price Roger V.
Published: December 2004

Using an NBS smoke test chamber, smoke evolution of a variety of plasticized and filled PVC formulations is studied. The lowest smoke evolution was provided by the joint use of alkylaryl phosphates and magnesium carbonate. Partial replacement of triaryl phosphates by chlorinated paraffins reduces significantly smoke evolution in the flaming mode without effect from antimony oxide.
Interaction effects and property retention in poly(vinyl chloride) compounds
Authors: Schreiber H. P. , Checkland J.
Published: December 2004

The influence of thermodynamic interactions among the components of a polymer system on mechanical properties and their retention on aging has been investigated. The systems considered involve plasticized poly(vinyl chloride)(PVC), and CaCO3 fillers. Inverse gas chromatography was used to measure interaction parameters, and to express these in terms of acid‐base concepts. Interaction data were obtained over a wide temperature range. It was shown that the volume of plasticizers retained by the PVC correlates with the measured interaction parameters. Similarly, the interaction parameters identify a CaCO3 filler preferred for reinforcing rigid PVC, and a different CaCO3 filler for use in given PVC‐plasticizer combinations. The mechanical properties of filled PVC (up to 40 phr CaCO3), and particularly the ultimate properties of the compounds, correlate with interaction concepts, as do property retention data after accelerated aging of the compounds at 100°C. It is concluded that component interaction parameters may provide useful guidelines to the formulation of compounds with superior properties and reduced property losses due to aging.
Measurement of PVC fusion (gelation)
Authors: Summers James W. , Rabinovitch Elvira B. , Booth Patrick C.
Published: December 2004

PVC fusion (gelation) occurs with melting of crystallites followed by recrystallization. This recrystallization, as it occurs at the primary particle boundary, physically ties together the structure into a three dimensional network. One way of measuring the extent of this three dimensional network structure is to measure the force required to deform the material through a zero land length capillary. We examine this test method for various molecular weight PVC compounds, with and without plasticizer, and for various degrees of grinding the product.
Rheology of flexible PVC compounds. Part I: The influence of resin crystallinity
Authors: Smith D. L. , Hookanson S. H. , Irvine J. L.
Published: December 2004

The changes occurring in torque during PVC processing in a torque rheometer have been interpreted in terms of the destruction of the supramolecular structure followed by a fusion of the grain fragments. In contrast to changes in torque, changes in elasticity occur in the absence of grain breakdown. It is proposed that the change in elasticity during processing is the result of changing crystallinity of the resin. In the early stages of processing, crystallites melt and elasticity decreases. As grains fuse together, new crystallites are formed in the previously unoccupied grain boundaries and the elasticity increases.
History of the development of processing aids for rigid PVC
Authors: Dunkelberger David L.
Published: December 2004

Bauman's polymerization of vinylchloride is generally regarded as the first documented preparation. British and German patents were granted in 1912 but the period from 1931 to 1933 based on work at BFGoodrich is considered as the beginnings of the flexible PVC industry, which grew rapidly during the 1940's and 1950's to become the dominant family of synthetic plastic resins. However, PVC degrades at about the same temperature required to process it. Therefore, without stabilizers and other additive modification, it could not have reached its present preeminence among rigid thermoplastics. The first processing aid patent appeared in 1953, and the first commercial processing aid appeared in 1957, which marked the beginning of the rigid PVC industry, the development of which is described in the paper.
Study of the effect of fumed silica on rigid PVC properties
Authors: Fellahi Said , Boukobbal Saadi , Boudjenana Farid
Published: December 2004

This study seeks to substitute fumed silica for chlorinated polyethylene (CPE) within a rigid PVC formulation intended for profile extrusion such as doors and window frames. The effect of fumed silica on both mechanical (tensile and impact) and thermal (Vicat point, HDT, and linear thermal expansion coefficient) properties were investigated. Five rigid PVC formulations were prepared, including a reference one (F1), then F1 with CPE, F1 with untreated silica, F1 with heat treated silica, and finally F1 with dried silica and a coupling agent. The effect of CPE on mechanical properties was very modest. On the other hand, CPE showed its inefficiency, in that HDT and Vicat point were decreased. Heat treated silica showed the greatest improvement in both mechanical and thermal properties. Untreated silica showed a small effect on both properties. Finally, the incorporation of coupling agent gave considerable improvement in both mechanical and thermal properties.
Performance of hybrid reinforcements in PVC composites. II: Use of surface‐modified mica and different cellulosic materials as reinforcements
Authors: Maldas D. , Kokta B. V.
Published: December 2004

The effect of the composition of various wood fibers and surface‐treated mica as well as different surface treatments of cellulosic materials on the mechanical properties of PVC composites has been evaluated. Cellulosics were surface modified by prior coating with maleic andydride (MA), mixtures of MA and Na‐silicate and isocyanate. The filler concentration was fixed at 25 wt%. Both tensile strength and modulus of composities filled solely with mica are superior to those of non‐treated wood fiber‐filled composities. while the reverse is true for impact strength (except for bagasse‐filled composities), ultimate elongation, and tensile toughness. Moreover, the mechanical properties of composities, with the exception of modulus, filled only with mica and/or non‐treated wood fibers are inferior to those of unfilled PVC. Compared to non‐treated fiber‐filled composites, properties improved when surface‐modified wood fibers were used alone, or along with mica. Isocyanate‐coated wood fibers ranked best with regard to the mechanical properties of the composities. Properties also changed with the change of wood species and compositions of mica and wood fibers. Experimental results indicate good compatibility between surface‐treated wood fibers/mica and PVC composities.
Confirmatory factor analysis of the interpersonal support evaluation list
Authors: Brookings Jeffrey B. , Bolton Brian
Published: December 2004

Summary and Conclusions

Cohen and Syme (1985) suggested that the most methodologically sound way of assessing the stress‐buffering properties of different functional support dimensions is through the introduction of experimental manipulations designed to elicit needs for specific support resources, and we agree. Of course, such tests are feasible only to the extent that it is possible to separate the support dimensions empirically. The results reported here indicate that despite considerable covariation among the latent variables corresponding to the four ISEL subscales, covariation that most likely represents the influence of a general second‐order support factor, there is also evidence that the four subscales provide sufficient unique information to warrant their retention in the ISEL.

From a practical standpoint, this means that researchers using the college version of the ISEL should follow Cohen and Hoberman's (1983) precedent of analyzing both individual subscale scoresand the total support score. In the meantime, improvements in the distributional properties of the individual ISEL items, perhaps through the four‐point item response format adopted recently by Cohen and his colleagues, should lead to more refined measurement of the functional support dimensions represented in the ISEL subscales and, subsequently, to more sensitive analyses of the stress‐buffering mechanisms associated with different support resources.
Scapholunate Ligament Injury Occurring with Scaphoid Fracture – A Rare Coincidence?
Authors: SCHÄDEL-HÖPFNER M. , JUNGE A. , BÖHRINGER G.
Published: December 2004

In a retrospective study the results of a series 34 wrist arthroscopies in 189 acute scaphoid fractures were analysed. Scapholunate ligament tears were found in 13 cases. In 10 cases there was complete disruption of scapholunate interosseous ligament causing dynamic instability. Partial ligament tears without instability were seen in three cases. Despite the limitations of this series we conclude that occurrence of scapholunate ligament injury with a scaphoid fracture may be more common than generally thought.
The Effect of Forearm Bracing on Radioulnar Impingement
Authors: BOYNTON J. F. , BUDOFF J. E. , CLIFFORD J. W.
Published: December 2004

The purpose of this clinical study was to compare patients’ symptoms and radioulnar convergence following distal radioulnar reconstruction with and without a functional brace on. Standardized radiographs were taken of the involved wrist at rest, while holding a weight, and during maximum power grip. All radiographs were then repeated while wearing a prefabricated functional brace (Maramed, Miami, FL). The functional brace did not decrease radioulnar convergence and, at rest, the brace actually increased radioulnar convergence. Despite this, all patients who experienced pain without the brace were pain free with the brace on. We conclude that forearm bracing may be a useful nonoperative treatment for residual pain following DRUJ salvage surgery, though its mechanism of action is unclear.
Donor‐transmitted parvovirus infection in a kidney transplant recipient presenting as pancytopenia and allograft dysfunction
Authors: Yango A. , Morrissey P. , Gohh R. , Wahbeh A. , A. Monaco
Published: December 2004

Abstract:Parvovirus B19 is a nonenveloped single‐stranded DNA virus that commonly causes a benign childhood infection typically manifesting as a ‘slapped‐cheek’ rash. In immunodeficient hosts, this infection can cause persistent anemia and occasionally pancytopenia. Recently, direct renal involvement has been reported in renal transplant recipients leading to various forms of glomerulopathy and allograft dysfunction. Most cases are primary infections and are donor transmitted through the transplanted organ. Clinical and virological response to intravenous immunoglobulin (Ig) is usually excellent.

We describe a case of donor‐transmitted parvovirus infection in a 23‐year‐old male who received his first cadaver renal transplant. The patient had an uncomplicated postoperative course with immediate graft function. Eight weeks after transplantation, he presented with fever, polyarthralgia, pancytopenia, and allograft dysfunction. Serological studies revealed elevated IgM titers against parvovirus B19. A renal biopsy was performed, which showed no evidence of acute rejection but with moderate degree of tubular damage. Parvovirus B19 viral DNA was detected in the renal tissue via polymerase chain reaction (PCR). The patient received a 10‐day course of intravenous Ig (400 mg/kg/day) with excellent response. His blood count normalized and the allograft improved to baseline function.

The incidence of parvovirus infection in renal transplant patients is probably underestimated, because patients are not routinely screened for it and anemia and/or pancytopenia in these patients are often ascribed to immunosuppressive drugs. Because this infection is treatable, we conclude that parvovirus B19 infection should be actively considered in transplant patients presenting with pancytopenia and allograft dysfunction.
Incidence of histoplasmosis following allogeneic bone marrow transplant or solid organ transplant in a hyperendemic area
Authors: Vail G.M. , Young R.S. , Wheat L.J. , Filo R.S. , Cornetta K. , Goldman M.
Published: December 2004

Abstract:Questions have arisen regarding the risk of developing symptomaticHistoplasma capsulatuminfection among patients who undergo transplant‐related immunosuppression in areas endemic for histoplasmosis. Our medical center is located in a hyperendemic area for histoplasmosis, where three large outbreaks occurred since 1978. We undertook a retrospective chart review of 137 patients who received allogeneic bone marrow transplant and of 449 patients who received solid organ transplant from January 1994 to December 1996 in order to assess the incidence of active histoplasmosis. Charts were reviewed before and after transplantation for clinical outcomes,H. capsulatumserologies and antigen results, and microbiological and radiological results. After a mean follow‐up duration exceeding 16 months, no patient was diagnosed with histoplasmosis. In the absence of an outbreak, histoplasmosis is a rare infection following the immunosuppression of allogeneic bone marrow or solid organ transplantation even in a hyperendemic area. Pre‐transplant serologies or chest radiographs consistent with prior infection were not associated with post‐transplant histoplasmosis.
Immortalized bone‐marrow derived pig endothelial cells
Authors: Seebach Jörg D. , Schneider Mårten K. J. , Comrack Christopher A. , LeGuern Annie , Kolb Stefan A. , Knolle Percy A. , Germana Sharon , DerSimonian Harout , LeGuern Christian , Sachs David H.
Published: December 2004

Abstract: Primary cultures of porcine endothelial cells (EC) can only be maintained for a limited number of passages. To facilitate studies of xenogeneic human anti‐pig immune responses in vitro, pig microvascular bone‐marrow (BM) and macrovascular aortic EC were obtained from our herd of partially inbred miniature swine, homozygous for the major histocompatibility locus, and immortalized with a modified SV40 large T vector. The resulting BM‐derived (2A2) and aortic (PEDSV.15) immortalized EC lines showed unlimited growth and EC phenotype as indicated by expression of von Willebrand Factor (vWF) and low density lipoprotein (LDL) receptors as well as by formation of typical cobblestone monolayers. Ultrastructural studies revealed morphological similarities in primary and immortalized EC. Flow cytometry analysis demonstrated constitutive SLA class I expression by all lines whereas SLA class II was only expressed after stimulation with porcine IFNγ. Furthermore, pig CD34 mRNA was detected by Northern blot analysis in primary and immortalized aortic EC but not in 2A2. Both EC lines expressed a number of myeloid markers, adhesion molecules and xeno‐antigens, the latter being determined by binding of human natural antibodies. Gene transfer into the porcine EC lines was successfully performed by electroporation or calcium‐phosphate transfection, as well as by adenoviral infection. Finally, the functional similarity between primary and immortalized EC was demonstrated in adhesion and cytotoxicity assays. Together, these results suggest that 2A2 and PEDSV.15 represent valuable tools to study both human cellular and humoral immune responses in vitro against pig EC derived from microvascular and large vessels.
A survey technique for estimating the proportion and sensitivity in a dichotomous finite population
Authors: Huang Kuo‐Chung
Published: December 2004

In this paper, a simple survey technique to measure the sensitivity of survey issues is presented. It can be applied to estimate the population proportion as well as the probability that a respondent truthfully states that he or she bears a sensitive character when experienced in a direct response survey. An unbiased estimator of mean square error for direct response survey is obtainable so as to be able to judge the effect on the accuracy in estimation. It is also found that the proposed technique is more efficient than some traditional techniques. A simple extension for polychotomous situations can be developed as well.
Transfusion‐associated GVHD: 10 years’ experience at the American University of Beirut—Medical Center
Authors: Aoun Elie , Shamseddine Ali , Chehal Aref , Obeid Maya , Taher Ali
Published: December 2004

BACKGROUND: Although rare, transfusion‐associated GVHD (TA‐GVHD) is a fatal complication of blood transfusion in which active lymphocytes from the donor attack and destroy recipient organs and tissues.

STUDY DESIGN AND METHODS: A search of patient records was carried out at the American University of Beirut—Medical Center, looking for patients who developed TA‐GVHD over a 10‐year period extending from 1991 to 2001. Relevant information was collected and analyzed.

RESULTS: A total of 10 records were found as a result of this search. All were immunocompetent and received fresh nonleukoreduced, nonirradiated blood. The majority received the transfusion at outside periphery hospitals. They received different treatment modalities. The mortality rate was 100 percent.

CONCLUSION: TA‐GVHD is a serious complication with very high mortality. Effective prevention guidelines should be established in Lebanon including irradiation and the creation of a central blood bank.
Reduction of febrile but not allergic reactions to RBCs and platelets after conversion to universal prestorage leukoreduction
Authors: Paglino Justin C. , Pomper Gregory J. , Fisch Gene S. , Champion Melanie H. , Snyder Edward L.
Published: December 2004

BACKGROUND:  Between January 1995 and November 1998, at Yale‐New Haven Hospital, 25 percent of RBCs transfused were processed through prestorage or bedside leukoreduction filters, chosen on a per patient basis (selective leukoreduction [SLR]). Between January 1995 and July 1999, 30 percent of platelet concentrates (PCs) were infused through bedside leukoreduction filters. In an attempt to decrease febrile nonhemolytic transfusion reactions (FNHTR), a change was made from SLR to universal prestorage leukoreduction (UPL) for RBCs between November 1998 and December 1999 and for random donor PCs between July 1999 and January 2000. FNHTR and allergic transfusion reactions (ATR) reported from January 1995 through December 2002 were reviewed.

STUDY DESIGN AND METHODS:  For retrospective observational analysis, blood bank data were available on the number of RBCs and PCs transfused, percent products leukoreduced, and rate of FNHTR and ATR from 1995 through December 2002. After dividing this time period into three phases (SLR, transition, and UPL), these data were evaluated using odds ratio (ORs) and Student's t tests.

RESULTS:  A total of 145,369 RBCs and 137,982 PCs (29,487 PC pools) transfused between January 1995 and December 2002 were evaluated. For RBCs, the relative FNHTR rate decreased 47.1 percent, from 0.34 percent (SLR) to 0.18 percent (UPL) (p < 0.0001). ATR rates for RBCs showed 0.09 percent for both SLR and UPL groups (p > 0.05, NS). For PCs, the FNHTR relative rate decreased 93.1 percent, from 2.18 percent for SLR to 0.15 percent for UPL (p < 0.0001). Rates for ATR were 0.49 percent (SLR) and 0.35 percent (UPL) (p > 0.05, NS).

CONCLUSIONS:  A significant decrease in the frequency of posttransfusion FNHTR, but not ATR, for RBCs and PCs followed introduction of 100‐percent UPL. The data support the hypothesis that the practice of UPL of RBCs and PCs decreases the frequency of FNHTR and thus improves patient care over the practice of selective leukoreduction.
Immobility – a major risk factor for development of pressure ulcers among adult hospitalized patients: a prospective study
Authors: Lindgren Margareta , Unosson Mitra , Fredrikson Mats , Ek Anna‐Christina
Published: December 2004

Objective : To identify risk factors associated with pressure ulcer development among adult hospitalized medical and surgical patients.

Design : A prospective comparative study including 530 adult patients from medical and surgical wards. Registered Nurses made the data collection on admission and once a week for up to 12 weeks. The risk assessment scale used was the Risk Assessment Pressure Sore (RAPS) scale, including the following variables; general physical condition, activity, mobility, moisture, food intake, fluid intake, sensory perception, friction and shear, body temperature and serum albumin.

Results : Sixty‐two (11.7%) patients developed 85 pressure ulcers. The most common pressure ulcer was that of nonblanchable erythema. Patients who developed pressure ulcers were significantly older, hospitalized for a longer time, had lower scores on the total RAPS scale, had lower weight and lower diastolic blood pressure than nonpressure ulcer patients did. In the multiple logistic regression analyses using variables included in the RAPS scale immobility emerged as a strong risk factor. When adding remaining significant variables in the analyses, mobility, time of hospitalization, age, surgical treatment and weight were found to be risk factors for pressure ulcer development.

Conclusion : It is confirmed that immobility is a risk factor of major importance for pressure ulcer development among adult hospitalized patients. The results also indicate that the RAPS scale may be useful for prediction of pressure ulcer development in clinical practice.
The efficacy of antimalarial monotherapies, sulphadoxine–pyrimethamine and amodiaquine in East Africa: implications for sub‐regional policy
Authors:   The East African Network for Monitoring Antimalarial Treatment (EANMAT)
Published: December 2004

Between 1998 and 2001, Kenya, Uganda, Tanzania, Zanzibar, Rwanda and Burundi changed antimalarial drug policy, in the face of widespread chloroquine resistance. The new first‐line treatment is either sulphadoxine–pyrimethamine (SP) monotherapy, or a combination of SP with either chloroquine or amodiaquine. Two national malaria control programmes, Burundi and Zanzibar, have decided upon amodiaquine‐artesunate as their first‐line treatment, although SP will continue to fill this role until the new policy can be implemented. Given the broad uniformity of parasite chemoresistance in the six countries, The East African Network for Monitoring Antimalarial Treatment (EANMAT) has focused attention on, and worked towards, a sub‐regional antimalarial drug policy, where the evidence base would be the entire portfolio of network in vivo test results. Currently, there are several different antimalarial drug policies within the EANMAT area: the intention is to eventually replace this plethora of policies with a single, sub‐regional policy based upon combination therapy. Currently, successful malaria treatment depends primarily upon the efficacy of SP, and of amodiaquine, which is either a component of first‐line treatment, or the second line drug. This report addresses the results of WHO in vivo tests on these two monotherapies within the network. Results are analysed to assess the evidence for change in parasite susceptibility over time; the range of susceptibility to each drug within countries, and the implications of test results on policy.
Partial Restoration of Cytokine Profile Despite Reconstitution of Cytomegalovirus‐Specific Cell‐Mediated Immunity in Human Immunodeficiency Virus‐Infected Patients During Highly Active Antiretroviral Treatment
Authors: Alfonzo M. , Blanc D. , Troadec C. , Eliaszewicz M. , Gónzalez G. , Scott‐Algara D.
Published: December 2004

We reconstituted cytomegalovirus (CMV)‐specific T‐cell responses in human immunodeficiency virus‐1‐positive, CMV‐positive patients receiving highly active antiretroviral treatment (HAART). We used several combinations of functionality parameters to determine the degree of T‐lymphocyte reconstitution obtained during 1 year of treatment. Untreated patients displayed CMV‐specific cytotoxic T‐lymphocyte (CTL) activity despite the absence of CMV‐specific lymphoproliferative responses (LPRs) and despite the fact that interferon‐γ (IFN‐γ) and interleukin‐2 (IL‐2) were not secreted. The absence of LPRs, IFN‐γ and IL‐2 before antiretroviral treatment suggests that CMV‐specific immunity was deregulated despite the high CD4+ T‐cell counts presented by our cohort, which are critical to the reactivation of CMV disease. After 6 months of HAART, CTL activity had increased compared with the baseline, as had the levels of secreted IFN‐γ and LPR. However, the levels of specific IL‐2 produced did not change during therapy, and no specific IL‐2 was detected during the follow‐up period. Taken together, our findings suggest that 1 year of HAART led to the recovery of some, but not all, CMV‐specific responses in our cohort of patients.
Genetic Heterogeneity of Autoimmune Disorders in the Nonobese Diabetic Mouse
Authors: Johansson Å. C. M. , Lindqvist A.‐K. B. , Johannesson M. , Holmdahl R.
Published: December 2004

The nonobese diabetic mouse is highly susceptible not only to diabetes but to several autoimmune diseases, and one might suspect that these are controlled by a shared set of genes. However, based on various gene‐segregation experiments, it seems that only a few loci are shared and that each disorder is influenced also by a unique set of genes.
Analysis of Hepatitis B Virus‐Immunoglobulin Isotype Complexes by a Novel Immuno‐Capture Polymerase Chain Reaction Method
Authors: Zhou Y. L. , Wang S. Y. , Zhang J. Y. , Peng X. X.
Published: December 2004

Hepatitis B virus (HBV) can be present in the circulating blood either as free virus or as a virion‐immunoglobulin (Ig) complex. Presently, it remains unclear what specific role each Ig plays in the clearance of HBV. In this study, a novel method that combined immuno‐capture and polymerase chain reaction (PCR) amplification was used for detecting and distinguishing different HBV‐Ig complexes. Three isotypes of Ig (IgM, IgG and IgA) bound to HBV were detected in the four clinically defined stages of HBV infection in 108 patients. The results showed that all the three isotypes of Ig could bind to HBV, and the patterns of HBV‐Ig complexes varied according to disease categories. Interestingly, the frequency of HBV DNA‐Ig complexes in hepatitis B e antigen (HBeAg)‐positive patients was significantly lower than that in HBeAg‐negative patients. All the data suggest that the three isotypes of HBV DNA‐Ig circulating immune complex (CIC) may have different biological meanings. In summary, HBV bound to an antibody is a common feature of hepatitis B, and immuno‐capture PCR is a valuable method for the analysis of the composition of the immune complexes. The detection of HBV‐Ig complexes may provide new and valuable insights into HBV pathogenesis.