bluuebunny/crossref_metadata_2025 huggingface dataset:
New Procedure for Quantitative Elemental Analysis by Laser-Induced Plasma Spectroscopy
Authors: Ciucci A. , Corsi M. , Palleschi V. , Rastelli S. , Salvetti A. , Tognoni E.
Published: October 2003

A new procedure, based on the laser-induced plasma spectroscopy (LIPS) technique, is proposed for calibration-free quantitative elemental analysis of materials. The method here presented, based on an algorithm developed and patented by IFAM-CNR, allows the matrix effects to be overcome, yielding precise and accurate quantitative results on elemental composition of materials without use of calibration curves. Some applications of the method are illustrated, for quantitative analysis of the composition of metallic alloys and quantitative determination of the composition of the atmosphere.
Influence of Droplets with Net Charge in Inductively Coupled Plasma Atomic Emission Spectroscopy and Implications for the Easily Ionizable Element Chemical Matrix Effect
Authors: Xu Qiang , Mattu Gevan , Agnes George R.
Published: October 2003

In the generation of an aerosol by pneumatic nebulization, concurrent with the production of a distribution of droplet sizes is a second distribution of net charge on the droplets. The influence that the droplets with net charge exert, spatially, on Ca(II) emission in the inductively coupled plasma (ICP) has been examined in the absence and presence of NaCl, an easily ionized element chemical matrix. Tertiary aerosol droplet size distributions were also measured. A mesh positioned in the spray chamber was used to establish an electric field between it and the grounded solution being nebulized. A 200 V dc potential applied to the mesh discriminated against the transport of droplets with net charge to the plasma. For samples that contained 100 mM NaCl, the full width at half-maximum of the Ca(II) emission profile viewed at 10 mm above the load coil was significantly reduced with 200 V applied to the mesh. The source of off-axis analyte emission enhancement low in the plasma in the presence of a NaCl matrix has been attributed to desolvation of the droplets with net charge beyond the coulomb fission limit, causing progeny droplets to be created within the aerosol. Droplets with net charge comprise ∼ 50% of the aerosols studied in this work, and these droplets do have a role in determining the analyte emission profiles in the inductively coupled plasma.
Evaluation of a Desolvating Microconcentric Nebulizer in Inductively Coupled Plasma Mass Spectrometry to Improve the Determination of Arsenic in Steels
Authors: Coedo Aurora G. , Dorado Teresa , Padilla Isabel
Published: October 2003

A desolvating microconcentric nebulizer (D-MCN) was used in inductively coupled plasma mass spectrometry (ICP-MS) in order to improve the determination of As in steels. To dissolve the samples, we applied a hydrochloric-nitric-hydrofluoric acid decomposition procedure. The isobaric interference of 40Ar35Cl+ due to the presence of Cl from the hydrochloric acid was minimized by using the desolvating device. Compared to results achieved with cross-flow nebulization, the As sensitivity was found to be 2.4 times higher, while the depression matrix effect caused by 0.1% m/v of Fe in the As signal was 3 times lower. The limit of quantification (LOQ) calculated as the concentration corresponding to 10 times the standard deviation of a procedural blank solution (0.1% m/v pure iron solution) was 0.12 μg g−1 (10 times better than that for the cross-flow nebulizer), and the background equivalent concentration (BEC) was about 25 times lower due to the absence of the most significant polyatomic interferences. The relative standard deviation calculated from six replicates at a concentration level of 10 times the detection limit was 0.8%. Three certified reference materials from the National Institute of Standard and Technology—NIST 365, 2165, and 2167—were analyzed; and recovery tests were performed on pure iron solutions spiked with different As contents. The close agreement of the values demonstrates the accuracy of the method.
Ion Dynamics of Plasmas Induced in Elemental Targets by Femtosecond Laser Irradiation
Authors: Pakhomov Andrew V. , Roybal Amanda J. , Duran Michael S.
Published: October 2003

The energies and number densities of ions emitted from laser-induced plasmas were studied by means of a simple time-of-flight technique. The plasmas were formed on solid elemental targets exposed to focused pulses from a Ti: Sapphire mode-locked laser and regenerative amplifier. The pulse energy and length were 1.0 mJ and 100 fs, respectively, with irradiance at the target of 2 × 1013 W/cm2. Ion kinetic energies, number densities, and mass removal rates were measured as functions of atomic mass, repetition rate, and angular orientation of the target with respect to the detector. Ion velocities varied within the 5.0–30.0 km/s range, corresponding to an average kinetic energy of 20–50 eV. Observed angular distribution of ion energy and number density obeyed the simple cosine function, which varied slightly for different elements. The total number of atoms removed per pulse was about 2 × 1013, while the ion fraction varied in the range of 3.0–5.0% for the majority of studied elements. The estimated total ion kinetic energy per pulse was ∼ 1014 eV, which corresponds to ∼ 1.5% of laser pulse energy. Mass removal rates demonstrated a direct relationship to transport properties of free electrons.
Interference Phenomena at Transparent Layers in Glow Discharge Optical Emission Spectrometry
Authors: Hoffmann V. , Kurt R. , Kämmer K. , Thielsch R. , Wirth Th. , Beck U.
Published: October 2003

At the performance of depth profiling by glow discharge optical emission spectroscopy (GD-OES) the intensities of optical emission lines of sample and sputter gas elements are measured in dependence on the time of sputtering. Radio-frequency (rf) sputtering extended the field of application to nonconducting samples including transparent layers. For transparent coatings in the thickness range up to some micrometers, oscillations of measured intensities were observed. This behavior is explained by a thin-film interference effect and discussed for three different materials, i.e., SiO2, TiO2, and BaTiO3. As a result, a new procedure for the determination of either layer thickness or refractive index from GD-OES depth profiles is presented. This effect has to be considered for quantitative GD-OES analysis as well.
Rapid and Accurate Determination of Stern—Volmer Quenching Constants
Authors: Goodpaster John V. , McGuffin Victoria L.
Published: October 2003

In this work, a novel system has been designed, characterized, and validated for the determination of fluorescence quenching constants. Capillary flow injection methods are used to automate the preparation and mixing of the fluorophore and quencher solutions. Because of the small diameter of the capillary (75–200 μm), fluorescence measurements can be made without corrections for primary and secondary absorbance effects. The fluorescence spectrometer is equipped with a charge-coupled device (CCD) that has a detection limit of 3.0 × 10−9 M (2.3 ppb) and a linear dynamic range of 105 for integration times of 0.01–10 s. This spectrometer has a 300 nm spectral range with 1 nm resolution, allowing the fluorescence quenching constants to be calculated at single wavelengths or over integrated wavelength ranges. This system was validated by comparison to traditional methods for the determination of Stern–Volmer constants for alternant and nonalternant polycyclic aromatic hydrocarbons with nitromethane and triethylamine.
Line Shape Distortion in a Cube Corner Interferometer Due to Lateral Shift of a Cube Corner
Authors: Salomaa I. K.
Published: October 2003

The effects of lateral shifts of the cube corner mirror to the line shape of Fourier transform spectra have been studied. The line distortions that are presented have been detected on many occasions, and one probable cause for them is thermal expansion in the interferometer. A theoretical model for representing this phenomenon is presented. It appears that the positions of the spectral lines are shifted when either of the cube corners is moving at a constant distance from the optical axis of the interferometer. An approximate rule for the line shifts is found, and experimental results are also presented.
Two-Dimensional Near-Infrared Correlation Spectroscopy Studies on Composition-Dependent Spectral Variations in Ethylene/Vinyl Acetate Copolymers: Assignments of Bands Due to Ethylene Units in Amorphous, Disordered, and Orthorhombic Crystalline Phases
Authors: Ren Yanzhi , Shimoyama Masahiko , Ninomiya Toshio , Matsukawa Kimihiro , Inoue Hiroshi , Noda Isao , Ozaki Yukihiro
Published: October 2003

Generalized two-dimensional (2D) correlation spectroscopy has been applied to the study of the composition-dependent near-infrared (NIR) spectral changes in 11 different ethylene/vinyl acetate (EVA) copolymers with vinyl acetate (VA) content from 6 to 42 wt %. The 2D synchronous correlation analysis of the 11 NIR spectra has separated the bands due to ethylene units from those due to the VA units. The obtained results are consistent with those reached by the calculation of the second derivative and by chemometrics analysis reported in our previous paper. However, the 2D correlation analysis has given clearer evidence for the band separation. Two-dimensional asynchronous correlation analysis has revealed out-of-phase variations between some bands due to ethylene and some bands due to VA and has determined the order of intensity change between them. On the basis of the order of intensity change, the bands of ethylene in the orthorhombic crystalline phase have been discriminated from those in the amorphous and disordered phases. This paper discusses the potentials of three powerful techniques, 2D correlation analysis, the calculation of the second derivatives, and that of regression coefficients in chemometrics, in unraveling rather complicated NIR spectra.
Raman Spectroscopic Identification of Synthetic “Braggite” (Pt, Pd, Ni)S Samples in Comparison with Synthetic “Cooperite”
Authors: Pikl R. , De Waal D. , Merkle R. K. W. , Verryn S. M. C.
Published: October 2003

Raman spectra of synthetic “braggite” (Pt, Pd, Ni)S with variable Pt/Pd ratios (atomic ratios between 0.31 and 1.37) and saturated in Ni (up to 1.99 atomic %) have been recorded and compared with the Raman spectra of synthetic “cooperite” and the pure palladium and platinum sulfides. In order to obtain more information on the significant differences in the spectra of these synthetic samples, factor group analyses of “braggite” and “cooperite” have been performed.
Fourier Transform Raman Spectroscopy of Novel Aluminophosphate Molecular Sieves
Authors: Akolekar Deepak B. , Bhargava Suresh , van Bronswijk Wilhelm
Published: October 2003

New generation, small-, medium-, and large-pore metal-incorporated aluminophosphate (MeAPO) molecular sieves were investigated with the use of Fourier transform (FT) Raman spectroscopy. The Raman spectra of well-characterized, high-purity MeAPO molecular sieves such as AlPO-5, NiAPO-5, MAPO-11, SAPO-34, MAPO-36, MAPO-39, MAPO-43, SAPO-44, MAPO-46, and MAPO-50 have been obtained in the 150 3250 cm−1 region. The presence of different metals in the AlPO framework within a particular structure has also been studied by FT-Raman spectroscopy. Comparison of FT-Raman and Fourier transform infrared (FT-IR) spectra of the samples indicated that the structures of the MeAPOs are more easily distinguished by FT-Raman than by FT-IR spectroscopy and that the former can be used for identifying and characterizing these materials.
Histological Classification of Raman Spectra of Human Coronary Artery Atherosclerosis Using Principal Component Analysis
Authors: Deinum Geurt , Rodriguez Daniel , Römer Tjeerd J. , Fitzmaurice Maryann , Kramer John R. , Feld Michael S.
Published: October 2003

We present a nonparametric method of analysis of Raman spectra of coronary artery tissue to classify atherosclerotic lesions. The method correlates the principal component scores of the Raman spectra with the tissue pathology. A data set composed of 97 samples of human coronary artery was used to develop the diagnostic algorithm, and a second data set composed of 68 samples was then used to test this algorithm prospectively. The results show that the algorithm can accurately classify coronary artery tissue into three classes: nonatherosclerotic, noncalcified plaque, and calcified plaque. The accuracy of this classification scheme is comparable to that previously achieved by means of a biochemical analysis of the Raman spectra using the same data.
Raman Spectroscopic Study of the Aging and Nitration of Actinide Processing Anion-Exchange Resins in Concentrated Nitric Acid
Authors: Buscher C. T. , Donohoe R. J. , Mecklenburg S. L. , Berg J. M. , Tait C. D. , Huchton K. M. , Morris D. E.
Published: October 2003

Degradation of two types of anion exchange resins, Dowex 11 and Reillex HPQ, from the action of concentrated nitric acid (4 to 12 M) and radiolysis [from depleted uranium as UO22+ nitrate species and 239Pu as Pu(IV) nitrate species] was followed as a function of time with Raman vibrational spectroscopy. Elevated temperatures (∼ 50 °C) were used in the absence of actinide metal loading to simulate longer exposures of the resin to a HNO3 process stream and waste storage conditions. In the absence of actinide loading, only minor changes in the Dowex resin at acid concentrations ⩽10 M were observed, while at 12 M acid concentration, the emergence of a Raman peak at 1345 cm−1 indicates the addition of nitro functional groups to the resin. Similar studies with the Reillex resin show it to be more resistant to nitric acid attack at all acid concentrations. Incorporation of weakly radioactive depleted uranium as the UO22+ nitrate species to the ion-exchange sites of Dowex 11 under differing nitric acid concentrations (6 to 12 M) at room temperature showed no Raman evidence of resin degradation or nitration, even after several hundred days of contact. In contrast, Raman spectra for Dowex 11 in the presence of 239Pu as Pu(IV) nitrate species reveal numerous changes indicating resin alterations, including a new mode at 1345 cm−1 consistent with a Pu(IV)-nitrate catalyzed addition of nitro groups to the resin backbone.
Raman Spectroscopic Studies of the Thermal Decomposition of Molybdenum Oxide/2,2′-Bipyridine Compounds
Authors: Twu Jen , Yu Yang-Yann , Tang Chih-Wei , Wang Gwang-Jung , Chen Kuei-Hsien
Published: October 2003

The thermal decompositions of [MoO3(2,2′-bipy)], [Mo2O6(2,2′-bipy)], and [Mo3O9(2,2′-bipy)2] have been studied by Raman spectroscopy. Upon heating, [MoO3(2,2′-bipy)] loses 2,2′-bipyridine and converts to MoO3 through a stable intermediate, [Mo2O6(2,2′-bipy)], whereas [Mo3O9(2,2′-bipy)2] loses 2,2′-bipyridine and transforms to MoO3directly. Vibrational assignments for [MoO3(2,2′-bipy)], [Mo2O6(2,2′-bipy)], and [Mo3O9(2,2′-bipy)2] are proposed.
Effects of Temperature on Cyclohexane Raman Bands
Authors: Pelletier M. J.
Published: October 2003

The temperature dependence of 14 bands in the liquid cyclohexane Raman spectrum was determined from 229 Raman spectra collected over a temperature range of 7 to 73 °C. The changes in band position, width, and area are large enough to significantly affect quantitative analysis using Raman spectroscopy. For example, band area ratios for neat cyclohexane change by as much as 25% over a 60 °C temperature range. Mechanisms for the temperature dependence are discussed.
On the Implementation of Multielement Continuum Source Graphite Furnace Atomic Absorption Spectrometry Utilizing an Echelle/CID Detection System
Authors: True J. Bruce , Williams Robert H. , Denton M. Bonner
Published: October 2003

A continuum source, multielement graphite furnace atomic absorption spectrometer was developed that employed a high-resolution echelle polychromator with charge-injection device (CID) detection. The detection system employed a new device, the CID 38, and camera control unit, the SCM5000E, providing unique new capabilities. A data acquisition and analysis scheme was developed for the prototype system, and the instrument demonstrated detection limits approaching that of commercial line source graphite furnace atomic absorption spectroscopy (GFAAS). However, the performance degrades in the ultraviolet due to decreasing source output.
Determination of Impurities in Uranium and Plutonium Dioxides by Laser-Induced Breakdown Spectroscopy
Authors: Fichet P. , Mauchien P. , Moulin C.
Published: October 2003

Laser-induced breakdown spectroscopy (LIBS), a spectrochemical technique in which a laser beam is used as the excitation source, was applied to detect trace elements contained in uranium and plutonium dioxides. Partial spectra of plasmas, generated by focusing the second harmonic (Λ = 532 nm) of a pulsed Nd:YAG laser on UO2 and PuO2 targets at atmospheric pressure, were recorded. Eighteen impurities at concentrations of about 500 ppm (μg/g) and twelve at concentrations of about 100 ppm, respectively, were observed in the rich emission matrices UO2 and PuO2. The possibility of quantifying impurities in such matrices is discussed.
Optical Absorption and Fluorescence Spectral Imaging Using Fiber Bundle Image Compression
Authors: McClain Brian L. , Ma Jiaying , Ben-Amotz Dor
Published: October 2003

Optical absorption and fluorescence spectral imaging is performed by using the recently developed fiber-bundle image compression (FIC) technique in which an entire spectral image is collected in a single scan of a charged-coupled device (CCD) detector. Absorption imaging is demonstrated by mapping the optical absorbance of a stained microscopic lily plant stem section. Fluorescence imaging is demonstrated by mapping shifts in the ruby R1 fluorescence line to determine the pressure distribution in a microcrystalline ruby powder squeezed between two diamond surfaces. The advantages and limitations of the FIC method, relative to tunable filter and line imaging techniques, are discussed.
Reflectance Study of Milk in the UV-Visible Range
Authors: Räty Jukka A. , Peiponen Kai-Erik
Published: October 2003

Optical properties of milk were studied with the use of a recently developed reflectometer. The purpose of the study was, first, to test the applicability of the reflectometer in the estimation of real refractive index and scattering in turbid liquids and, second, to investigate the spectral properties of one particular turbid liquid, namely, milk. An expression for the reflectance of milk was constructed which takes into account the light scattering occurring in milk. With the application of a minimizing procedure to the reflectance data, it was possible to simultaneously obtain both the real refractive index and a scattering parameter for milk. The scattering parameter was observed to be linearly dependent on the milk fat concentration.
Diode Laser Measurements of HF Concentrations Produced from Heptane/Air Pan Fires Extinguished by FE-36, FM-200, FE-36 Plus APP, or FM-200 Plus APP
Authors: Skaggs R. R. , Daniel R. G. , Miziolek A. W. , McNesby K. L. , Herud C. , Bolt W. R. , Horton D.
Published: October 2003

Tunable diode laser absorption spectroscopy (TDLAS) is used to measure the time evolution of hydrogen fluoride (HF) concentrations produced from a series of enclosed heptane/air pan fires extinguished by either FE-36, FM-200, FE-36 plus ammonium poly-phosphate (APP), or FM-200 plus APP. For the fires studied, the change in HF gas concentration with time is dependent upon the fire-fighting chemical used to extinguish the re. The presence of APP is observed to reduce HF concentrations in the re enclosure. Visible attenuation spectroscopy is also used to measure the amount of light attenuation (obscuration) that occurs as a hand-held re extinguisher containing powdered fire fighting agent is released in the crew space of a M1-Abrams land combat vehicle.
Infrared Investigation of Acid Activation by PyBOP in Polystyrene/Divinylbenzene Supported Solid-Phase Synthesis
Authors: Pivonka Don E. , Palmer Donald L. , Gero Thomas W.
Published: October 2003

The infrared technology presented in this paper provides a mechanism for the detailed study of PyBOP [(1H-benzotriazole-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate] ester activation in a solid-phase supported chemical system. Prior to this work, formation of the alkoxyphosphonium salt had been postulated as a necessary reactive intermediate for formation of the triazole-activated ester in the PyBOP activation process; however, observation of the alkoxyphosphonium salt has not been reported at room temperature. The present work not only confirms the presence of the salt but further demonstrates it to be the primary activated species for couplings performed on the solid phase at room temperature. More important than the specific identification of the PyBOP activation method is the general introduction of a set of infrared analytical tools for analysis of solid-phase reaction mechanisms and kinetics.
Analytical Characterization of Reflected and Transmitted Light from Cellular Structural Material for the Parallel Beam of NIR Incident Light
Authors: Tsuchikawa Satoru , Tsutsumi Shigeaki
Published: October 2003

The results of several studies show clearly that the behavior of light transmitted in wood samples is considerably different from that of an ideal scattering medium. These observations suggest that the Kubelka–Munk theory (the K-M theory) cannot be applied directly to biological material with a cellular structure. We have developed new concepts to understand the optical characteristics of a sample having cellular structure for the illumination condition of the available spectrometers. Through a series of examinations, it became clear that the behavior of diffusely reflected light in wood was accurately described by the K-M theory. However, the behavior of its transmitted light was considerably different from that of an ideal scattering medium under the conditions of Lambert's cosine law. A two-component model of the diffusion process with respect to a parallel beam component of incident light was considered. Furthermore, the nth power cosine model of radiant intensity was introduced to be fitted for the actual state of the radiation in wood. On the basis of these optical models, the mean optical pathlength through the sample was calculated, which allowed the concept of the equivalent sample thickness to be derived. Over and above these considerations, generalized input/output equations for radiation were constructed by introducing the equivalent sample thickness into K-M equations. The absorbance calculated by such concepts agreed well with the experimental values.
Development of a Photoacoustic Trace Gas Sensor Based on Fiber-Optically Coupled NIR Laser Diodes
Authors: Beenen A. , Niessner R.
Published: October 2003

A novel photoacoustic sensor system for on-line monitoring of benzene, toluene, and xylene concentrations is described. The radiation emitted by near-infrared (NIR) laser diodes is coupled into a fiber and guided to the resonant cell. The resonator is operated at its lowest azimuthal resonance while the radiation enters the cell at two different locations. The fiber-optical approach allows for the use of various laser diodes with different wavelengths. This approach enables detection of many analytes in parallel and correction for spectral interferences with other substances. Measurements at the first overtone of the CH stretching vibrations (1.67 μm) are discussed. Detection limits obtained for benzene, toluene, and xylene are 70, 100, and 160 μg/L, respectively. In order to compensate for the spectral interferences of water vapor, the concentration of the latter was determined by using the 1.31 μm NIR laser diode. Water concentrations as low as 0.5 mg/L could be determined. Results of studies performed with two analytes at two different wavelengths simultaneously demonstrate the feasibility of the technique for analysis of mixtures.
Vibrational Spectroscopic Study of the Complexation of Mercury(II) by Substituted Acetates in Aqueous Solutions
Authors: Quilès Fabienne , Burneau André , Gross Nathalie
Published: October 2003

Attenuated total reflectance infrared (ATR-IR) and Raman spectroscopies are used to identify the complexed species of mercury(II) with acetate and some aliphatic derivatives in aqueous solutions, as a function of pH and metal-to-acetate ratio. The spectra of the free carboxylate ions, in their sodium salt solutions, and of the protonated molecules are shown for comparison and assigned below 1800 cm−1. Whatever the stoichiometries assumed [HgCH3COO+ up to Hg(CH3COO)42-], one structure is observed, principally via the stretching modes ν(CO2) and ν(CC), although two strong bands have a νs(CO2) character owing to an accidental coupling of this mode with δs(CH3) in all the acetate complexes. This coupling is demonstrated with the isotopic ligand CD3COO, which displays only one νs(CO2) band on account of the separation of this mode from δs(CD3). The splitting between νa(CO2) and νs(CO2) increases up to about 260 cm−1 for all the carboxylates under study, the value pointing to a hydrated monodentate form.
Rapid Determination of Cell Morphology in Eucalyptus Wood by Fourier Transform Raman Spectroscopy
Authors: Ona Toshihiro , Sonoda Tetsuya , Ito Kazuya , Shibata Masaru , Ootake Yoshisato , Ohshima Jyunichi , Yokota Shinso , Yoshizawa Nobuo
Published: October 2003

Analysis of cell morphology in native wood is a lengthy, multistep procedure, although it has a marked effect on product quality and the use of wood. The feasibility of using FT-Raman spectroscopy for rapid determination of cell length and cell wall ratio as cell morphology in native wood was examined with the use of wood meals of two Eucalyptus species, including samples of various ages and colors. The second-derivative transformation of Raman spectroscopic data and the partial least-squares regression revealed highly significant correlations between conventionally measured and Raman predicted values for cell length and cell wall ratio with correlation coefficient r > 0.9 and 0.8, respectively, in the calibration (for known samples, n = 55) and in the prediction (for unknown samples, n = 25).
Intermittent parathyroid hormone (1–34) enhances mechanical strength and density of new bone after distraction osteogenesis in rats
Authors: Seebach C. , Skripitz R. , Andreassen T. T. , Aspenberg P.
Published: October 2003

Distraction osteogenesis is used both for leg lengthening and for bone transportation in the treatment of fractures and non‐unions. The main problem with this method is that the time until full recovery may be up to a year, partly because of the time needed for the new formed bone to consolidate and become strong enough for weight bearing. We have studied whether intermittent parathyroid hormone (PTH(1–34)) could accelerate the consolidation of new formed bone after distraction osteogenesis in rats. Forty‐seven, 3‐months‐old male Sprague–Dawley rats underwent lengthening of the right femur using an external fixator. After a middiaphyseal osteotomy and a 7‐day latency period, the callus was distracted during 10 days, with a distraction rate of 0.25 mm twice a day. The consolidation time was either 20 days or 40 days after distraction was completed. A dose of 60 μg of human PTH(1–34)/kg body weight/injection or vehicle was given every second day beginning 30 days before the rats were killed. Both femura of each rat were subjected to mechanical testing and dual‐energy X‐ray absorptiometry. Blinded histological examination was done for the distracted femura.

In the 20 days consolidation experiment, PTH(1–34) increased ultimate load (56%), stiffness (117%), total regenerate callus volume (58%), callus BMC (24%) and histologic bone density (35%) compared to untreated distraction osteogenesis specimens. In the 40 days consolidation experiment, PTH(1–34) increased ultimate load (54%), stiffness (55%), callus BMC (33%) and histologic bone density (23%) compared to untreated distraction osteogenesis specimens. Total regenerate callus volume was unchanged.

The contralateral femur also became stronger, stiffer and denser under PTH(1–34) treatment, but to a lesser degree. PTH(1–34) might become useful to shorten the consolidation time after distraction osteogenesis in humans. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Arginine kinase overexpression improves Trypanosoma cruzi survival capability
Authors: Pereira Claudio A , Alonso Guillermo D , Ivaldi Soledad , Silber Ariel M , Alves Maria Júlia M , Torres Héctor N , Flawiá Mirtha M
Published: October 2003

Arginine kinase catalyzes the reversible transphosphorylation between adenosine diphosphate (ADP) and phosphoarginine, which is involved in temporal and spatial adenosine triphosphate (ATP) buffering. Here we demonstrate that the homologous overexpression of the Trypanosoma cruzi arginine kinase improves the ability of the transfectant cells to grow and resist nutritional and pH stress conditions. The stable transfected parasites showed an increased cell density since day 10 of culture, when the carbon sources became scarce, which resulted 2.5‐fold higher than the control group on day 28. Additional stress conditions were also tested. We propose that arginine kinase is involved in the adaptation of the parasite to environmental changes.
Structure of thioredoxin from Trypanosoma brucei brucei
Authors: Friemann Rosmarie , Schmidt Heide , Ramaswamy S. , Forstner Michael , Krauth-Siegel R.Luise , Eklund Hans
Published: October 2003

The three‐dimensional structure of thioredoxin from Trypanosoma brucei brucei has been determined at 1.4 Å resolution. The overall structure is more similar to that of human thioredoxin than to any other thioredoxin structure. The most striking difference to other thioredoxins is the absence of a buried carboxylate behind the active site cysteines. Instead of the common Asp, there is a Trp that binds an ordered water molecule probably involved in the protonation/deprotonation of the more buried cysteine during catalysis. The conserved Trp in the WCGPC sequence motif has an exposed position that can interact with target proteins.
Isolation of δ‐missulenatoxin‐Mb1a, the major vertebrate‐active spider δ‐toxin from the venom of Missulena bradleyi (Actinopodidae)1
Authors: Gunning Simon J , Chong Youmie , Khalife Ali A , Hains Peter G , Broady Kevin W , Nicholson Graham M
Published: October 2003

The present study describes the isolation and pharmacological characterisation of the neurotoxin δ‐missulenatoxin‐Mb1a (δ‐MSTX‐Mb1a) from the venom of the male Australian eastern mouse spider, Missulena bradleyi. This toxin was isolated using reverse‐phase high‐performance liquid chromatography and was subsequently shown to cause an increase in resting tension, muscle fasciculation and a decrease in indirect twitch tension in a chick biventer cervicis nerve‐muscle bioassay. Interestingly, these effects were neutralised by antivenom raised against the venom of the Sydney funnel‐web spider Atrax robustus. Subsequent whole‐cell patch‐clamp electrophysiology on rat dorsal root ganglion neurones revealed that δ‐MSTX‐Mb1a caused a reduction in peak tetrodotoxin (TTX)‐sensitive sodium current, a slowing of sodium current inactivation and a hyperpolarising shift in the voltage at half‐maximal activation. In addition, δ‐MSTX‐Mb1a failed to affect TTX‐resistant sodium currents. Subsequent Edman degradation revealed a 42‐residue peptide with unusual N‐ and C‐terminal cysteines and a cysteine triplet (Cys14‐16). This toxin was highly homologous to a family of δ‐atracotoxins (δ‐ACTX) from Australian funnel‐web spiders including conservation of all eight cysteine residues. In addition to actions on sodium channel gating and kinetics to δ‐ACTX, δ‐MSTX‐Mb1a caused significant insect toxicity at doses up to 2000 pmol/g. δ‐MSTX‐Mb1a therefore provides evidence of a highly conserved spider δ‐toxin from a phylogenetically distinct spider family that has not undergone significant modification.
Genetic epidemiology of alpha‐1 antitrypsin deficiency in North America and Australia/New Zealand: Australia, Canada, New Zealand and the United States of America
Authors: De Serres FJ , Blanco I , Fernández‐Bustillo E
Published: October 2003

Alpha‐1‐antitrypsin deficiency (AAT deficiency) is one of the most common serious hereditary disorders in the world, as its affects all major racial subgroups worldwide, and there are an estimated 120.5 million carriers and deficient subjects worldwide. This genetic disease is related to susceptibility for development of jaundice in infants, liver disease in children and adults and pulmonary emphysema in adults. Moreover, AAT deficiency carrier phenotypes (PiMS and PiMZ) and deficiency allele phenotypes (PiSS, PiSZ and PiZZ) are suspected to predispose subjects to a variety of other adverse health effects. Because there is a limited database on the number of individuals affected by this disease worldwide, we have collected data on control cohorts in genetic epidemiological studies published on case–control studies in the peer‐reviewed literature worldwide. Based on these data, we estimated the numbers of carriers and deficiency allele combinations for the two most common defective alleles, namely PiS and PiZ in 58 countries worldwide. The present paper focuses on the distribution of the PiS and PiZ deficiency alleles in Australia, Canada, New Zealand and the United States of America. A total of 31,042,232 individuals at risk for adverse health effects have been calculated in these four countries: 2,144,158 in Australia, 3,258,564 in Canada, 430,922 in New Zealand and 24,909,548 in the United States of America. The prevalences for all five phenotypic classes of AAT deficiency in each of these countries is as follows: Australia 1 out of 8.9, Canada 1 out of 9.8, New Zealand 1 out of 8.5 and the United States of America 1 out of 11.3. The geographical distribution of individual control cohorts and estimates of the numbers of carriers and deficiency allele phenotypes in each of these four countries are given in individual tables.
Association of EDNRA, but not WNK4 or FKBP1B, polymorphisms with essential hypertension
Authors: Benjafield AV , Katyk K , Morris BJ
Published: October 2003

In a study of the genetic basis of essential hypertension (HT), we tested four variants in three candidate genes not previously investigated in HT. These encoded the endothelin receptor type A (EDNRA), which transduces most of the vasoconstrictive properties of endothelin‐1, protein kinase lysine deficient 4 (WNK4) whose gene resides in a HT linkage region on chromosome 17, and FK506‐binding protein 1B (FKBP1B), which can reduce blood pressure by increasing nitric oxide. The variants were: for EDNRA, a G→A in the 5′‐UTR and C→T in exon 8; for WNK4, a tetranucleotide repeat in intron 10; and for FKBP1B, a T→C in exon 4. Subjects were Anglo‐Celtic white Australians and included 155 HTs with two HT parents and 245 normotensives (NTs) whose parents were both NT. For EDNRA, we found a weak association of the exon 8 variant with HT (p = 0.019) and association of the 5′‐UTR variant with elevation in systolic and diastolic blood pressure (BP) (p = 0.038 and 0.0031, respectively). The WNK4 intron 10 variant and the FKP1B exon 4 variant showed no association with HT, but tracking with BP was seen for the latter (p = 0.015 and 0.0011 for systolic and diastolic BP, respectively). Our study thus suggests possible involvement of EDNRA in essential HT.
A−61C and C−101G Hp gene promoter polymorphisms are, respectively, associated with ahaptoglobinaemia and hypohaptoglobinaemia in Ghana
Authors: Teye K , Quaye IKE , Koda Y , Soejima M , Tsuneoka M , Pang H , Ekem I , Amoah AGB , Adjei A , Kimura H
Published: October 2003

We have investigated the genetic basis for the Hp0 phenotype amongst 123 randomly selected Ghanaians. A total of 17 individuals were determined to be Hp0 phenotype, based on the classical method for Hp phenotyping of Hb‐supplemented plasma. Out of the 17 Hp0 individuals, nine subjects were further classified as ahaptoglobinaemic and eight as hypohaptoglobinaemic by Western blots and double immunodiffusion. We identified three previously known base substitutions (A−55G, A−61C and T−104A) and three new ones (C−101G, T−191G and C−242T) within the 5′ flanking region of the Hp gene. The A−61C base substitution significantly decreased transcriptional activity and was associated strongly with Hp2 allele and ahaptoglobinaemia. The C−101G substitution was similar in transcriptional activity to the wild‐type and was associated with Hp1S allele and hypohaptoglobinaemia. The Hpdel allele seen in Asian populations was absent. We conclude that the Hp0 phenotype in Ghana has a genetic basis that differs significantly from that seen in Asia.
Peroxisome proliferator‐activated receptor γ C161T polymorphisms and survival of Japanese patients with immunoglobulin A nephropathy
Authors: Song J , Sakatsume M , Narita I , Goto S , Omori K , Takada T , Saito N , Ueno M , Gejyo F
Published: October 2003

Peroxisome proliferator‐activated receptor γ (PPARγ) plays an important role in lipid metabolism, insulin sensitivity, atherogenesis, and immune regulation. A genetic polymorphism (C161T) at exon 6 of PPARγ gene (PPARG) was reported to be associated with the onset of coronary artery disease. However, there has been no report of an association with renal disease. Genomic DNAs were isolated from 225 Japanese patients with histologically confirmed immunoglobulin A nephropathy (IgAN). The PPARG C161T genotype was determined by polymerase chain reaction‐restriction fragment length polymorphism. The association of the polymorphism with renal prognosis in IgAN patients was analyzed using the Kaplan–Meier method and Cox proportional hazard regression model. The PPARG polymorphism was not associated with the renal survival rate. However, when patients were stratified into those either with or without hypertension at the time of diagnosis, the renal survival of the CT/TT genotypes was significantly better in those without hypertension than those with the CC genotype. We report that the PPARG C161T polymorphism is associated with the survival of IgAN patients without hypertension. The T allele of the polymorphism might have a protective effect on the progression of IgAN.
Omphalocele in trisomy 3q: further delineation of phenotype
Authors: Yatsenko SA , Mendoza‐Londono R , Belmont JW , Shaffer LG
Published: October 2003

We report a case of a patient with omphalocele, dysmorphic features, and mild developmental delay associated with a chromosomal aberration. Chromosome studies showed that the propositus carries a maternally derived unbalanced translocation der(4)t(3;4)(q27.3;q32.3), resulting in trisomy for region 3q27.3→qter and monosomy for 4q32.3→qter. Because the association between dup3q and omphalocele has been reported in several cases, we analyzed the data on 93 previously reported patients with partial trisomy of the long arm of chromosome 3 and compared the clinical features between the cases. The imbalance of chromosome 3 in the patient was further defined by fluorescence in situ hybridization (FISH) studies using bacterial artificial chromosome (BAC) clones. BAC clone RP11‐171N2 was identified as a breakpoint‐spanning clone in the patient and his mother. Based on our comparative analysis, we have delineated that the smallest region of overlap (SRO) associated with omphalocele is from BAC 171N2 to 3qter. We hypothesize that the SRO contains a gene(s) important in normal abdominal wall development and is of potential interest for further investigation.
Genetic susceptibility to neural tube defect pregnancy varies with offspring phenotype
Authors: Relton CL , Wilding CS , Jonas PA , Lynch SA , Tawn EJ , Burn J
Published: October 2003

Neural tube defects (NTDs) have a well‐established genetic basis, although no single genetic factor has been identified as a major risk factor in NTD susceptibility. A large number of association studies have been conducted to investigate the possibility that NTD susceptibility is linked to polymorphic variation in genes involved in early embryonic development or in the absorption or metabolism of folate, a nutrient that has been clearly associated with a reduction in the risk of NTD pregnancy. A study of three candidate gene polymorphisms at loci implicated in folate absorption and metabolism has been conducted on a population of 211 mothers of a heterogeneous mix of NTD phenotypes: 59% spina bifida aperta (SBA), 20.3% spina bifida occulta (SBO), 17% anencephaly, and 3.7% other NTD. Allele and genotype frequencies were stratified according to offspring NTD phenotype, and variation in the level of NTD risk was associated with different phenotypes. All the three variants (MTHFR 677C > T, GCPII 1561C > T, and RFC‐1 80G > A) were shown to significantly influence the risk of anencephalic pregnancy. In addition, the MTHFR 677C > T variant conferred a modest protective effect in SBO mothers and the total NTD mother group, but not in SBA mothers. The RFC‐1 80G > A variant elevated the risk of SBO and anencephalic pregnancy. The findings of this study suggest that NTD phenotypic heterogeneity may help explain the mixed findings of previous association studies and that different polymorphisms may hold differing degrees of significance for the various NTD phenotypes.
FH‐Pyrgos: a novel mutation in the promoter (−45delT) of the low‐density lipoprotein receptor gene associated with familial hypercholesterolemia
Authors: Dedoussis GVZ , Pitsavos C , Kelberman D , Skoumas J , Prassa ME , Choumerianou DM , Stefanadis C , Humphries SE , Toutouzas P
Published: October 2003

In a patient with familial hypercholesterolemia (FH), we have identified a new mutation (−45delT) in repeat 3 of the low‐density lipoprotein receptor (LDLR) gene promoter. Analysis of a neutral polymorphism in the LDLR mRNA from the patient's white blood cells showed that the expression of one allele was significantly reduced, and cells have only 24% of LDLR activity by binding and uptake of DiI‐LDL. Transient transfection studies using a luciferase gene reporter revealed that the −45delT mutation considerably reduces the transcriptional activity of the LDLR promoter and strongly suggest that the mutation is the cause of the FH phenotype.
The role of habitat selection behavior in population dynamics: source–sink systems and ecological traps
Authors: Kristan, III William B.
Published: October 2003

Ecological traps, poor‐quality habitat that nonetheless attract individuals, have been observed in both natural and human‐altered settings. Until recently, ecological traps were considered a kind of source–sink system, but source–sink theory does not model maladaptive habitat choice, and therefore cannot accurately represent ecological traps or predict their population‐level consequences. Although recent models of ecological traps addressed this problem, they used patch‐based models containing only two habitats that were very different from one another, but were internally homogeneous. These sorts of patch models may not apply to many real populations, and using them for populations in landscapes with mosaic or gradient habitat structures may be misleading. I developed models that treat source–sink dynamics and ecological traps as special cases of a single process, in which the attractiveness and quality of the habitat are separate variables that can be either positively or negatively related, and in which habitat quality varies continuously throughout the landscape. As expected, sinks are less detrimental to populations than ecological traps, in which preferential use of poor habitat elevates extinction risk. Furthermore, ecological traps may be undetected, and may even appear to be sources, when population sizes are large, but may still prevent recovery in spite of the availability of high‐quality habitat when populations drop below threshold levels. Conservation biologists do not routinely consider the possibility that apparent sinks are actually traps, but since traps should be associated with the rapidly changing and novel habitat characteristics primarily produced by human activities, ecological traps should be considered an important and potentially widespread conservation concern.
Genetic diversity and invasibility: a test using a model system with a novel experimental design
Authors: Weltzin J. F. , Muth N. Z. , Von Holle B. , Cole P. G.
Published: October 2003

Biological invasion is one aspect of ecosystem function that may be controlled by the biological diversity of the invaded community, and there have been a number of recent studies that investigated relationships between diversity and invasibility. Most experimental studies report that higher species or functional group diversity increases resistance to invasion, but the role of genetic diversity is unknown. We used a model organism,Arabidopsis thaliana(Brassicaceae), to investigate relationships between genotypic richness and community invasibility by creating communities with 1, 2, 4, and 8 genotypes ofA. thalianaat constant low (417 plants m−2) and high (834 plants m−2) densities, that once established, were invaded with a congener,Arabidopsis suecica. To reduce the potential effects of methodological confounding related to “sampling effects,”“variance reduction effects,” or confounding of abundance with diversity, we (1) created random communities from a relatively large pool of functionally and phenotypically similar genotypes, (2) evaluated individual and community traits across richness treatments, and (3) analyzed similarity of communities within treatments (for “quasi‐ replication”) and between adjacent treatments (for “nestedness”). Genotypic richness had no effect onA. suecicademography (emergence, survivorship), size (biomass, rosette area), or reproductive potential (rates of bolting and fruiting or number and size of bolts). In contrast, the density ofA. thalianagenotypes had strong effects on the size and reproductive potential ofA. suecica, which suggests that characteristics of the recipient community other than genotypic richness (e.g. light) form the most important determinant of community invasibility. Individual‐ and community‐level traits of community members (cover, biomass, survivorship) did not differ among richness treatments, and within‐ and between‐treatment similarity was reduced (relative to other recent experiments) but not eliminated. We evaluate our results vis‐a‐vis recent analyses of diversity‐invasibility experiments, and provide directions for future investigations of genetic diversity.