bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbazole‐bound ferrocenium salt as an efficient cationic photoinitiator for epoxy polymerization
Authors: Wang Tao , Li Bao Sh , Zhang Li X
Published: May 2005

The low absorption of cyclopentadienyl‐Fe‐cumene hexafluorophosphate (I‐261) above 300 nm limits its utilization of longer wavelength emission from light sources. We report here the synthesis and photoactivity of a carbazole‐bound ferrocenium salt, cyclopentadienyl‐Fe‐carbazole hexafluorophosphate ([Cp‐Fe‐carbazole]+PF6−), which efficiently absorbs radiation between 300 and 400 nm. Its photoactivity is higher than that of I‐261 as a cationic photoinitiator. When the photosensitizer benzoyl peroxide (BPO) is employed, [Cp‐Fe‐carbazole]+PF6− can obviously be sensitized. Two other ferrocenium salts with amine groups, cyclopentadienyl‐Fe‐aniline hexafluorophosphate ([Cp‐Fe‐aniline]+PF6−) and cyclopentadienyl‐Fe‐p‐methylaniline hexafluorophosphate ([Cp‐Fe‐p‐methylaniline]+PF6−) were also studied. As photoinitiators, they perform poorly and can not be sensitized by BPO. Copyright © 2005 Society of Chemical Industry
Differential proteome analysis of conditioned media to detect Smad4 regulated secreted biomarkers in colon cancer
Authors: Volmer Martin W. , Stühler Kai , Zapatka Marc , Schöneck Anna , Klein‐Scory Susanne , Schmiegel Wolff , Meyer Helmut E. , Schwarte‐Waldhoff Irmgard
Published: May 2005

Smad4 is a tumor suppressor gene primarily involved in carcinogenesis of the pancreas and colon. The functional inactivation of Smad4 is a late step genetically. In pancreatic carcinogenesis, loss of Smad4 marks the transition to invasive growth. In colorectal cancers, the frequency of Smad4 inactivation is markedly increased in metastatic cancers. We have established cell biological models, re‐expressing Smad4 in deficient human cancer cells, in which we could show that Smad4 is adequate to suppress tumor growth through suppression of angiogenic and invasive properties. Thus, pairs of Smad4‐re‐expressing and Smad4‐deficient cells are prone to model the progression from premalignant stages to carcinomas in the carcinogenic process and may provide access to Smad4 targets of high clinical relevance. We present here a “differential secretome analysis”, comparing all the proteins released in vitro from the Smad4‐deficient and Smad4‐re‐expressing SW480 human colon carcinoma cells. The differential secretome catalog comprises more than 25 proteins including proteases and protease inhibitors, as well as established tumor biomarkers. In conclusion, this approach proved to be a sensitive tool to specifically detect Smad4 targets relevant for tumor‐stroma interactions. It is also able to reflect complex alterations of cellular physiology. Moreover, the results support our hypothesis that human tumor markers detectable in serum may be identified through differential secretome analyses.
Proteomic changes in the pressure overloaded right ventricle after 6 weeks in young rats: Correlations with the degree of hypertrophy
Authors: Faber Matthijs J. , Dalinghaus Michiel , Lankhuizen Inge M. , Bezstarosti Karel , Dekkers Dick H. W. , Duncker Dirk J. , Helbing Willem A. , Lamers Jos M. J.
Published: May 2005

Right ventricular (RV) hypertrophy is an important problem in congenital heart disease. We determined the alterations in phenotype that occur in the initial phase of RV hypertrophy and their possible correlations with the degree of hypertrophy. Therefore, we performed a differential proteomic profiling study on RV hypertrophy using an animal model of pulmonary artery banding (PAB) in parallel with hemodynamic characterization. The RV homogenates were subfractionated in myofilament and cytoplasmic proteins, which subsequently were separated by two‐dimensional gel electrophoresis (2‐DE), excised, and analyzed by mass spectrometry (MS). The cytoplasmic fraction showed expression changes in metabolic proteins, indicative of a shift from fatty acid to glucose as a substrate for energy supply. Up‐regulation of three HSP‐27s (1.9‐, 1.7‐, and 3.5‐fold) indicated an altered stress response in RV hypertrophy. Detailed analysis by immunoblotting and MS showed that two of these HSP‐27s were at least phosphorylated on Ser15. The myofilament fraction showed up‐regulation of desmin and α‐B‐crystallin (1.4‐and 1.3‐fold, respectively). This alteration in desmin was confirmed by 1‐DE immunoblots. Certain differentially expressed proteins, such as HSP‐27, showed a significant correlation with the RV weight to the body weight ratio in the PAB rats, suggesting an association with the degree of hypertrophy.
Effect of solvent on cis‐to‐trans isomerization of 4‐hydroxyazobenzene aggregated through intermolecular hydrogen bonds
Authors: Kojima Masanobu , Nebashi Satomi , Ogawa Keiichiro , Kurita Noriyuki
Published: May 2005

The half‐life (τ1/2) for thermal isomerization of cis‐4‐hydroxyazobenzene (c‐HOAB) to its trans isomer is highly dependent on the solvent used. For non‐aromatic solvents, the cis isomer is extremely unstable at 293 K (τ1/2 < 1 min in methanol and acetonitrile and 6 min in cyclohexane), whereas the cis isomer is surprisingly stable in benzene (τ1/2 = 125 min). However, addition of hydrogen chloride and triethylamine in benzene causes a remarkable decrease in τ1/2. On the basis of ab initio molecular orbital calculations of the binding energies and the optimum structures of c‐HOAB–solvent complexes, a mechanism for the thermal cis‐to‐trans isomerization reaction involving hydrogen‐bonded dimers and complexes is suggested. Copyright © 2005 John Wiley & Sons, Ltd.
Vinyl or isopropenyl substituents as experimental and theoretical probes for diamagnetic anisotropies of aromatic hydrocarbons
Authors: Haefelinger Guenter , Knapp Wolfgang , Zuschneid Thomas , Dietrich Frank Peter
Published: May 2005

Vinyl or isopropenyl substituents can be used to indicate anisotropy effects in the surroundings of benzenoid hydrocarbons by experiments together with APUDI model and ab initio GIAO MO calculations from the difference in geminal proton splittings of the olefinic substituents. Geometry optimizations as a function of the torsional angle between substituents and aromatic planes were performed in two polarized basis sets for the HF, B3LYP and MP2 methods. Calculated splittings range between −0.70 and 0.48 ppm. Comparison with experimental 1H NMR shifts does not lead precisely to the determination of the experimentally apparent effective torsional angle. Copyright © 2005 John Wiley & Sons, Ltd.
Metabolic mechanisms of insecticide resistance in the western flower thrips, Frankliniella occidentalis (Pergande)
Authors: Espinosa Pedro J , Contreras Josefina , Quinto Vicente , Grávalos Carolina , Fernández Esther , Bielza Pablo
Published: May 2005

The interactions between six insecticides (methiocarb, formetanate, acrinathrin, deltamethrin, methamidophos and endosulfan) and three potential synergists (piperonyl butoxide (PBO), S,S,S‐tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM)) were studied by topical exposure in strains selected for resistance to each insecticide, and in a susceptible strain of Frankliniella occidentalis (Pergande). In the susceptible strain PBO produced appreciable synergism only of formetanate, methiocarb and methamidophos. Except for endosulfan, PBO synergized all the insecticides to varying degrees in the resistant strains. A very high level of synergism by PBO was found with acrinathrin, which reduced the resistance level from 3344‐ to 36‐fold. PBO slightly synergized the carbamates formetanate (4.6‐fold) and methiocarb (3.3‐fold). PBO also produced a high synergism of deltamethrin (12.5‐fold) and methamidophos (14.3‐fold) and completely restored susceptibility to both insecticides. DEF did not produce synergism with any insecticide in the resistant strains and DEM was slightly synergistic to endosulfan (3‐fold). These studies indicate that an enhanced detoxification, mediated by cytochrome P‐450 monooxygenases, is the major mechanism imparting resistance to different insecticides in F occidentalis. Implications of different mechanisms in insecticide resistance in F occidentalis are discussed. Copyright © 2005 Society of Chemical Industry
The intrinsic toxicity of several neonicotinoids to Lygus lineolaris and Hyaliodes vitripennis, a phytophagous and a predacious mirid
Authors: Bostanian Noubar J , Hardman John M , Ventard Estelle , Racette Gaétan
Published: May 2005

The tarnished plant bug Lygus lineolaris (Palisot de Beauvois) is a key pest of apples in eastern Canada and, currently, chemical control is the only way to manage this pest. Hyaliodes vitripennis (Say) is a univoltine indigenous predacious mirid and an integral part of biological control programs for apples in certain regions of Quebec. In worst‐case laboratory conditions, thiamethoxam, thiacloprid and acetamiprid were exceptionally toxic to this predacious mirid. The adults were more susceptible than the nymphs. However, the residual toxicity of these neonicotinoids to L lineolaris in orchards was very short‐lived. Because of the short residual toxicity, neonicotinoids should be applied when L lineolaris is at maximum abundance and well before eggs of H vitripennis hatch in late June. Copyright © 2005 Society of Chemical Industry
Singlet oxygen formation by porous Si in solution
Authors: Fujii Minoru , Usui Motofumi , Hayashi Shinji , Gross Egon , Kovalev Dmitri , Künzner Nicolei , Diener Joachim , Timoshenko Victor Yu.
Published: May 2005

Singlet oxygen formation by porous Si in solution has been demonstrated. It has been shown that the absorption band of 1,3‐diphenylisobenzofuran (DPBF) in benzene becomes smaller, i.e., DPBF is degraded, by irradiating green or red light if the powder of fresh porous Si is dispersed in the solution. The effect was drastically suppressed by the formation of a monolayer of backbonded oxide at the surface of nanocrystals. The degradation was accelerated when the solution was bubbled with oxygen gas. These results indicate that electronic excitation of Si nanocrystals is transferred to molecular oxygen dissolved in solution, resulting in the formation of singlet oxygen. Generated singlet oxygen reacts with DPBF, forming endoperoxides, which in turn decompose to yield irreversible products. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhanced control of porous silicon morphology from macropore to mesopore formation
Authors: Ouyang Huimin , Christophersen Marc , Fauchet Philippe M.
Published: May 2005

Porous silicon (PSi) is a versatile material that possesses a wide range of morphologies. There are two main types of microstructures that are widely used and well studied: branchy mesoporous silicon with pore sizes from 10 nm to 50 nm and classical macroporous silicon with pore sizes from 500 nm to 20 µm. Much less work has been done on structures with intermediate pore sizes from 100 nm to 300 nm. Applications such as immunoassays biosensing can greatly benefit from the intermediate morphology due to the larger pore openings compared to mesopores, and increased internal surface compared to classical macropores. In this work we demonstrate well‐defined macropore of 150 nm diameter in average and precise control of the porous silicon morphology transition from smooth macropores to branchy mesopores on one substrate with one electrolyte. A multilayer structure (microcavity) consisting of both mesopores and macropores is presented. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stain etching of silicon pillars and macropores
Authors: Mills David , Nahidi Mona , Kolasinski Kurt W.
Published: May 2005

We used a XeCl excimer laser (308 nm, ∼3 J cm–2) and chemically enhanced laser ablation in the presence of SF6 to create arrays of silicon pillars. Etching of these pillars with KOH leads to arrays of macropores whose morphology depends on surface crystallography. Several new stain etchants – containing some combination of HF, NH4HF2, HCl, HNO3, Fe(III), Mn(VII) and water – have been used to cover these structures with a layer of microporous silicon. Both pillars and macropores are black, i.e., exhibit low reflectivity across the visible spectrum. When porosified, pillars exhibit visible photoluminescence whose angular distribution differs from that of planar porous silicon with significantly more intensity at high angles. The peak photoluminescence wavelength depends on the stain etchant composition and exposure to air. The use of metal ions in place of HNO3 in the stain etchant ameliorates the production of gas bubbles and leads to more uniform films. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A three‐dimensional waveguide substrate for DNA‐microarrays based on macroporous silicon
Authors: Dertinger Stephan K. , Klühr Marco , Sauermann Alexander , Thein Kerstin
Published: May 2005

In this paper we present a three‐dimensional waveguide structure with unique optical and fluidic properties and demonstrate its application as a substrate for DNA microarrays. The structure is fabricated by thermal oxidation of a macroporous silicon membrane with a periodic pattern of discrete microchannels running perpendicular through the substrate. Partial oxidation generates compartments with channel walls that are completely converted into SiO2 but leaves a rectangular grid of silicon walls separating the SiO2 compartments. We demonstrate that the SiO2 walls act as optical waveguides and the opaque silicon walls divide the substrate into optically isolated compartments. In DNA microarray experiments, we show that the silicon walls of the compartments prevent cross talk between adjacent DNA spots. The structure is compatible with all conventional read‐out techniques such as fluorescence, chemiluminescence, and precipitation staining. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Possible model of protein nucleation and crystallization on porous silicon
Authors: Stolyarova S. , Baskin E. , Chayen N. E. , Nemirovsky Y.
Published: May 2005

The problem of macromolecular nucleation and crystallization on porous silicon surface is investigated theoretically. The fractality of the porous silicon layer is exploited. It is shown that the effective surface density of adsorbed particles on a fractal self‐similar surface significantly exceeds that on a flat surface. The resulting local supersaturation explains enhanced nucleation phenomena associated with porous silicon. In addition, the self‐affine fractal surface exhibits quasi‐periodicity that can facilitate long‐range ordering of the nucleated molecules, i.e. the crystallization process. Moreover, small elastic constants of porous silicon are favorable for the surface periodicity tuning to different lattice parameters of growing crystals. The anomalous large scaling range (from silicon interatomic distance up to 100 nm) is favorable for the crystallization of wide range of big macromolecules such as proteins. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of porous silicon formation on stiction in surface micromachined MEMS structures
Authors: Bhattacharya Enakshi , Rani Helen Anitha , Venu Babu U. , Rao P. R. S. , Bhat K. N. , Martin J.
Published: May 2005

Stiction, or adhesion of components to one another, is a major failure mechanism in surface micromachined MEMS. In this paper we discuss roughening of the surface of polysilicon, which forms the structural layer in surface micromachining, by the formation of porous silicon and its effect on stiction. The adhesivity of the surface is investigated by measurements of contact angle and the roughness is measured by a surface profiler. Measurements to estimate stiction on surface micromachined cantilevers and accelerometers are reported. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and light‐emission modification in chemically‐etched porous silicon
Authors: Navarro‐Urrios D. , Pérez‐Padrón C. , Lorenzo E. , Capuj N. E. , Gaburro Z. , Oton C. J. , Pavesi L.
Published: May 2005

After electrochemical etching, we have made a study of the effects generated on p+‐type porous silicon layers when they are left in presence of the electrolyte for different post‐etching times. Using an interferometric technique, we have monitored the change of its porosity during the post‐etch process due to a chemical dissolution mechanism. These data are complemented with a study of photoluminescence and transmission electron microscopy measurements for different post‐etching times. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Si/SiO2 nanocomposite by CVD infiltration of porous SiO2
Authors: Amato G. , Borini S. , Rossi A. M. , Boarino L. , Rocchia M.
Published: May 2005

The aim of the present paper is to report first results on an innovative method for producing Si/SiO2 nanocomposites. Starting from a porous oxide structure, we infiltrated Si by Chemical Vapour Deposition of SiH4, under controlled conditions. In this way, we succeeded in infiltrating Si into the SiO2 template. Porous oxide is obtained by dry oxidation of mesoporous Si. By means of the electrochemical process used for producing porous Si, an interconnected pore structure is obtained. This allows for Si infiltration, giving rise, in principle, to an interconnected network of Si crystallites, in which electrical carriers are easily driven. Efficient charge injection in Si nanocrystals is of crucial importance for several applications, from electroluminescence to memory devices. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of the experimental procedure in the specific surface measurement by chemical dissolution of n+ nanoporous silicon
Authors: Descamps Y. , Dufour‐Gergam E. , Halimaoui A.
Published: May 2005

In this paper, we used the chemical dissolution of porous silicon (PS) to determine the specific surface area of PS obtained from n+ substrate. Two initial porosity values (62 and 39% with 1 µm and 0.5 µm thickness respectively) and two dissolution etchants were used. It is shown that the dissolution experimental procedure influences the extracted specific surface value. Under good dissolution conditions, we calculed 90 m2/cm3 and 130 m2/cm3 surface area value respectively. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Integrating packaging suppliers into the supply/demand chain
Authors: Dominic Chris
Published: May 2005

This paper presents the results from qualitative studies done on leading‐edge companies in supply/demand chain management in Sweden. The aim of the study was to create a knowledge base, identify the network integrators and, with reference to previous studies conducted in the packaging industry, analyse the development for packaging suppliers. Copyright © 2005 John Wiley & Sons, Ltd.
Assay of rotenone in river water by high‐throughput tandem mass spectrometry and multiple‐reaction monitoring methodology
Authors: Di Donna Leonardo , Mazzotti Fabio , Sindona Giovanni , Tagarelli Antonio
Published: May 2005

The high‐throughput analytical approach proposed for the assay of rotenone in lake and river waters presented here is based on atmospheric pressure chemical ionization (APCI) multiple‐reaction monitoring (MRM) methodology whereby the analyte and internal standard solutions are directly analyzed, without any previous chromatographic separation. The very good accuracy is obtained by the critical choice of a reference compound that shows gas‐phase chemistry similar to that of the analyte, by producing the same product ions selected for the MRM‐based assay. Copyright © 2005 John Wiley & Sons, Ltd.
Ion‐pairing reversed‐phase liquid chromatography/electrospray ionization mass spectrometric analysis of 76 underivatized amino acids of biological interest: a new tool for the diagnosis of inherited disorders of amino acid metabolism
Authors: Piraud Monique , Vianey‐Saban Christine , Petritis Konstantinos , Elfakir Claire , Steghens Jean‐Paul , Bouchu Denis
Published: May 2005

Seventy‐six molecules of biological interest for the diagnosis of inherited disorders of amino acids (AA) metabolism have previously been demonstrated to be detectable in electrospray ionization tandem mass spectrometry (ESI‐MS/MS) positive mode without derivatization. Reversed‐phase liquid chromatography (RPLC) separation on different C18 columns using various perfluorinated carboxylic acids as ion‐pairing agents has been found suitable for coupling with MS/MS, and for the separation of AA. A new procedure was optimized in order to replace the usual ion‐exchange chromatographic, post‐column ninhydrin derivatization, time‐consuming routine method. This procedure allowed an adequate separation of all the molecules from other known interfering compounds, and a throughput of two samples per hour. Quantification limits for each molecule were found to be compatible with their measurement in plasma and urine. We validated the qualitative part of the method by analyzing plasma and urine samples from patients affected with several inherited disorders of AA metabolism. We validated the quantification of 16 AA using their stable isotopes as internal standard. The calibration curves were linear over the range 0–3 mM. The quantitative results obtained with the new method on 105 plasma and 99 urine samples were in good agreement with those obtained by the established routine method. Spiking experiments and precision results were also satisfactory. Copyright © 2005 John Wiley & Sons, Ltd.
Single run measurements of drug‐protein binding by high‐performance frontal analysis capillary electrophoresis and mass spectrometry
Authors: Wan Hong , Östlund Åsa , Jönsson Stefan , Lindberg Walter
Published: May 2005

A novel drug‐protein binding measurement method based on high‐performance frontal analysis and capillary electrophoresis (HPFA/CE) is presented. A single run measurement approach is proposed to circumvent utilization of a calibration curve that is often performed with HPFA. A sensitive mass spectrometer is applied as a detector enabling the measurement of in vitro protein binding at lower drug concentrations. Unbound free fraction and binding constants can be determined by a single run measurement by consecutive injections of an internal drug standard, a buffer plug and a drug‐protein mixture. Effects of injection volumes on peak height and plateau profile were investigated in two different separation systems, non‐volatile buffer and volatile buffer, with UV and mass spectrometry detection, respectively. A simplified one‐to‐one binding model is employed to evaluate the proposed method by using both single and multiple drug concentrations to measure the unbound free fraction and calculate the binding constants of some selected compounds. The method is suitable for rapid and direct screening of the binding of a drug to a specific protein or drug‐plasma protein binding. Copyright © 2005 John Wiley & Sons, Ltd.
Quantitative analysis of 23‐hydroxybetulinic acid in mouse plasma using electrospray liquid chromatography/mass spectrometry
Authors: Yang Min , Wang Guang Ji , Wang Su Jun , Li Xiao Tian , Xu Yu Ping , Wang Song Pei , Xiang Jing De , Pan Shang Ren , Cao Guo Xian , Ye Wen Cai
Published: May 2005

23‐Hydroxybetulinic acid is a newly isolated derivative of betulinic acid. The agent exhibits potential anti‐tumor activity and functions in this regard via apoptosis. In support of pharmacokinetic and toxicological evaluations, a new assay based on liquid chromatography/mass spectrometry (LC/MS) was developed for the quantitative analysis of 23‐hydroxybetulinic acid. Sample preparation consisted of extraction of the plasma by the addition of methylene chloride followed by centrifugation. Aliquots of the supernatant were analyzed using an isocratic reversed‐phase high‐performance liquid chromatography (HPLC) system coupled to a negative ion electrospray mass spectrometer. Molecules of 23‐hydroxybetulinic acid and the internal standard limonin were detected using selected ion monitoring at m/z 471 and 469, respectively. The limit of detection of 23‐hydroxybetulinic acid was 0.05 pg (0.11 fmol) injected on‐column (10 pg/mL, 5 μL injection volume), and the limit of quantitation was 10 pg (21.19 fmol, 2 ng/mL, 5 μL injection volume). 23‐Hydroxybetulinic acid was stable in plasma samples at –20°C for at least 3 weeks. The intra‐day and inter‐day coefficients of variation of the assay were 3.0 and 4.8%, respectively. The utility of the assay was demonstrated by measuring 23‐hydroxybetulinicacid in mouse plasma following intragastric administration (IG) in vivo. Pharmacokinetic parameters were calculated using the 3P97 pharmacokinetic software package. A two‐compartment, first‐order model was selected for pharmacokinetic modeling. The result showed that after IG of 200 mg/kg 23‐hydroxybetulinic acid, the plasma concentrations reached peaks at 2 h with Cmax of 3.1 μg/mL. The 200 mg/kg 23‐hydroxybetulinic acid suspension IG doses were found to have long elimination half‐lives of 25.6 h and low bioavailability of 2.3%. No interference was noted due to endogenous substances. These analytical methods should be of value in future studies related to the development and characterization of 23‐hydroxybetulinic acid. Copyright © 2005 John Wiley & Sons, Ltd.
Development of a rapid and specific assay for detection of busulfan in human plasma by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry
Authors: dos Reis Ederson Oliveira , Vianna‐Jorge Rosane , Suarez‐Kurtz Guilherme , Lima Edson Luiz da Silva , Azevedo Débora de Almeida
Published: May 2005

A sensitive and specific assay for detection of busulfan in human plasma was developed. The assay is based on rapid isolation of busulfan by liquid‐liquid extraction with ethyl acetate, and detection by high‐performance liquid chromatography with electrospray ionization and tandem mass spectrometry. 1,6‐Bis(methanesulfonyloxy)hexane, a synthesized analogue of busulfan, was used as the internal standard (IS). The acquisition was performed in the multiple reaction monitoring mode; busulfan and the IS were detected with no interferences from plasma matrix. The method was linear over the range 5–2500 ng mL−1, with r2 > 0.99 and a run time of only 3.5 min. The intra‐ and inter‐assay precisions were in the ranges 2.1–11.9% and 3.2–10.1%, respectively, and the intra‐ and inter‐assay accuracies were 92.2–107.6% and 94.7–104.1%, respectively. The absolute recoveries were 82.0% (20 ng mL−1), 90.6% (1000 ng mL−1) and 80.0% (2000 ng mL−1) for busulfan, and 89.1% for the IS (1000 ng mL−1). The limits of detection and quantification were 2 and 5 ng mL−1, respectively. The validated method was successfully applied to analyze plasma samples obtained from six adults receiving doses of 1 mg kg−1 in a conditioning regimen prior to bone marrow transplantation. A marked intra‐patient variation in busulfan concentrations during the steady state was observed, which limits the application of pharmacokinetic modeling and suggests that continuous therapeutic monitoring is necessary for adequate individualized dosing. In this regard, the present assay brings important advantages relative to other methods described in the literature, i.e., it is highly specific and simple to perform, with a rapid chromatographic run time (3.5 min), and the whole procedure can be completed in 4–5 h, which would permit dose corrections after the third dose allowing earlier and better dosing adjustments towards the target level of busulfan. Copyright © 2005 John Wiley & Sons, Ltd.
Peptide photodissociation at 157 nm in a linear ion trap mass spectrometer
Authors: Kim Tae‐Young , Thompson Matthew S. , Reilly James P.
Published: May 2005

The photodissociation by 157 nm light of singly‐ and doubly‐charged peptide ions containing C‐ or N‐terminal arginine residues was studied in a linear ion trap mass spectrometer. Singly‐charged peptides yielded primarily x‐ and a‐type ions, depending on the location of the arginine residue, along with some related side‐chain fragments. These results are consistent with our previous work using a tandem time‐of‐flight (TOF) instrument with a vacuum matrix‐assisted laser desorption/ionization (MALDI) source. Thus, the different internal energies of precursor ions in the two experiments seem to have little effect on their photofragmentation. For doubly‐charged peptides, the dominant fragments observed in both photodissociation and collisionally induced dissociation (CID) experiments are b‐ and y‐type ions. Preliminary experiments demonstrating fragmentation of multiply‐charged ubiquitin ions by 157 nm photodissociation are also presented. Copyright © 2005 John Wiley & Sons, Ltd.
Iodoacetamide‐alkylated methionine can mimic neutral loss of phosphoric acid from phosphopeptides as exemplified by nano‐electrospray ionization quadrupole time‐of‐flight parent ion scanning
Authors: Krüger Ralf , Hung Chien‐Wen , Edelson‐Averbukh Marina , Lehmann Wolf D.
Published: May 2005

Formation of S‐carbamidomethylmethionine (camMet) occurs as a side reaction during cysteine alkylation with iodoacetamide (IAA). In collision‐induced dissociation, peptides with camMet show an abundant neutral loss of 2‐(methylthio)acetamide (C3H7NOS = 105.025 Da) at moderate collision offset values which are similar to those optimal for loss of phosphoric acid (H3PO4 = 97.977 Da). Neutral loss analysis is used for spotting of phosphopeptides which contain phosphoserine (pSer) or phosphothreonine (pThr) residues. In the case where precursor ions cannot be accurately assigned in the survey spectrum (e.g. due to low ion abundance or signal overlap), the mass accuracy of a neutral loss tandem mass spectrometry (MS/MS) analysis depends on the precursor ion isolation window. For the charge states 2+, 3+ or 4+, a typical 3.5 Da precursor isolation window results in neutral loss windows of 7, 10.5 or 14 Da, respectively. Consequently, neutral loss of 105 Da from alkylated methionine residues can mimic the phosphoserine/phosphothreonine‐specific neutral loss of 98 Da. In the evaluation of quadrupole time‐of‐flight (QTOF) parent ion scan data for neutral loss of H3PO4, this interference was frequently observed. It is illustrated in this study using the analysis of ovalbumin phosphorylation as an example. The +80 Da molecular weight shift connected with phosphorylation at serine or threonine may also be mimicked by carbamidomethylation of methionine through a combination with sodium adduction (+57 Da +22 Da = +79 Da). For highly sensitive neutral loss analysis of serine and threonine phosphorylation, careful data inspection is recommended if reduction and alkylation by IAA is employed. Copyright © 2005 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionization mass spectrometry of collected bioaerosol particles
Authors: Kim Jae‐Kuk , Jackson Shelley N. , Murray Kermit K.
Published: May 2005

A method was developed for collection and analysis of bioaerosols by matrix‐assisted laser desorption/ionization (MALDI) time‐of‐flight mass spectrometry using a modified Andersen N6 bioaerosol collector. The overall goal of the study was to develop methods for obtaining mass spectra with minimal reagents and treatment steps for potential use in remote collection and analysis systems. Test bioaerosol particles were generated from a nebulized E. coli bacterial suspension and collected on MALDI targets placed in an Andersen N6 single‐stage aerosol impactor. The bioaerosols were mixed with matrix either by deposition on a bare target with the matrix solution added later, or by deposition on a target pre‐coated with matrix. The matrix compounds α‐cyano‐4‐hydroxycinnamic acid (CHCA) and sinapic acid (SA) were tested and the SA matrix was found to give the best results in number of peaks, resolution, and signal‐to‐noise ratio. Deposition of bioaerosol particles onto the matrix pre‐coated target did not produce signal in the m/z region above 1000, but the signal could be recovered with the addition of a 1:1 (v/v) acetonitrile/water solvent. Addition of solvent by pipette to the pre‐coated targets after particle deposition recovered signal comparable to the dried‐droplet sample preparations, whereas solvent sprayed into the impactor recovered fewer peaks. Deposition on pre‐coated targets with post‐collection solvent addition was superior to deposition on bare target followed by post‐collection addition of matrix solution. Copyright © 2005 John Wiley & Sons, Ltd.
Quantitative determination of cetirizine enantiomers in guinea pig plasma, brain tissue and microdialysis samples using liquid chromatography/tandem mass spectrometry
Authors: Gupta Anubha , Jansson Britt , Chatelain Pierre , Massingham Roy , Hammarlund‐Udenaes Margareta
Published: May 2005

Sensitive enantioselective liquid chromatographic assays using tandem mass spectrometric detection were developed and validated for the determination of S‐cetirizine (S‐CZE) and R‐cetirizine (R‐CZE) in guinea pig plasma, brain tissue, and microdialysis samples. Enantioselective separation was achieved on an α1‐acid glycoprotein column within 14 min for all methods. A cetirizine analog, ucb 20028, was used as internal standard. Cetirizine and the internal standard were detected by multiple reaction monitoring using transitions m/z 389.1 → 200.9 and 396.1 → 276.1, respectively. The samples were prepared using protein precipitation with acetonitrile. For guinea pig plasma, the assay was linear over the range 0.25–5000 ng/mL for both S‐CZE and R‐CZE, with a lower limit of quantification (LLOQ) of 0.25 ng/mL. For the brain tissue and microdialysis samples, the assays were linear over the range 2.5–250 ng/g and 0.25–50 ng/mL, respectively, and the LLOQ values were 2.5 ng/g and 0.25 ng/mL, respectively. The intra‐ and inter‐day precision values were ≤7.1% and ≤12.6%, respectively, and the intra‐ and inter‐day accuracy varied by less than ±8.0% and ±6.0% of the nominal value, respectively, for both enantiomers in all the matrices investigated. Copyright © 2005 John Wiley & Sons, Ltd.
Probabilistic behavior of asymmetric level compressed tries
Authors: Devroye Luc , Szpankowski Wojcieh
Published: May 2005

Level‐Compressed (in short LC) tries were introduced by Andersson and Nilsson in 1993. They are compacted versions of tries in which, from the top down, maximal height complete subtrees are level compressed. We show that when the input consists of n independent strings with independent Bernoulli (p) bits, p ≠ 1/2, then the expected depth of a typical node is in probability asymptotic to

where H − p log p − (1 − p) log (1 − p) is the Shannon entropy of the source, and H−∞ = log (1 / min(p, 1 − p)). The height is in probability asymptotic to

where H2 = log(1/(p2 + (1−p)2)). © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Maximum weight independent sets and matchings in sparse random graphs. Exact results using the local weak convergence method
Authors: Gamarnik David , Nowicki Tomasz , Swirszcz Grzegorz
Published: May 2005

LetG(n,c/n) andGr(n) be ann‐node sparse random graph and a sparse randomr‐regular graph, respectively, and letI(n,r) andI(n,c) be the sizes of the largest independent set inG(n,c/n) andGr(n). The asymptotic value ofI(n,c)/nasn→ ∞, can be computed using the Karp‐Sipser algorithm whenc≤e. For random cubic graphs,r= 3, it is only known that .432 ≤ lim infnI(n,3)/n≤ lim supnI(n,3)/n≤ .4591 with high probability (w.h.p.) asn→ ∞, as shown in Frieze and Suen [Random Structures Algorithms 5 (1994), 649–664] and Bollabas [European J Combin 1 (1980), 311–316], respectively. In this paper we assume in addition that the nodes of the graph are equipped with nonnegative weights, independently generated according to some common distribution, and we consider instead the maximum weight of an independent set. Surprisingly, we discover that for certain weight distributions, the limit limnI(n,c)/ncan be computed exactly even whenc>e, and limnI(n,r)/ncan be computed exactly for somer≥ 1. For example, when the weights are exponentially distributed with parameter 1, limnI(n,2e)/n≈ .5517, and limnI(n,3)/n≈ .6077. Our results are established using the recently developedlocal weak convergencemethod further reduced to a certainlocal optimalityproperty exhibited by the models we consider. We extend our results to maximum weight matchings inG(n,c/n) andGr(n). For the case of exponential distributions, we compute the corresponding limits for everyc> 0 and everyr≥ 2. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Prenatal diagnosis of horseshoe kidney by measurement of the renal pelvic angle
Authors: Cho J. Y. , Lee Y.‐H. , Toi A. , Macdonald B.
Published: May 2005

Objective

The aim of this study was to evaluate the usefulness of measurement of the angle between bilateral renal pelves on axial views in the prenatal ultrasonographic diagnosis of horseshoe kidney.

Methods

We retrospectively measured the renal pelvic angle in 19 fetuses with horseshoe and 20 fetuses with normal kidneys in the second and third trimesters. Renal pelvic angle was defined as the angle between the long axis of the renal pelves on the axial view of the abdomen. We compared the renal pelvic angles of horseshoe and normal kidneys with unpaired t‐test. Taking 140° as a cut‐off value, we calculated the sensitivity, specificity and accuracy of pelvic angle measurement for the prenatal diagnosis of horseshoe kidney.

Results

The mean pelvic angles in the fetuses with horseshoe kidney were 116° and 110° in the second and third trimester, respectively. In the normal fetuses, the equivalent angles were 172° and 161°. The difference between the two groups was statistically significant (P < 0.01). Using 140° as the discriminating criterion, the sensitivity, specificity and accuracy of renal pelvic angle measurement for the prenatal diagnosis of horseshoe kidney were all 100%. Fifteen of 19 fetuses with horseshoe kidney had no other abnormality. Four (21%) fetuses had severe complex abnormalities which were associated with trisomy 18 in three cases.

Conclusion

Observation and measurement of the renal pelvic angle is a simple and useful method in the prenatal diagnosis of the horseshoe kidney. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
A new three‐dimensional automatic bodymarker system for transvaginal ultrasonography
Authors: Kuwata T. , Taniguchi N. , Matsubara S. , Ono T. , Itoh K. , Suzuki M.
Published: May 2005

Objective

To evaluate the accuracy and usefulness of a newly developed three‐dimensional automatic bodymarker system for transvaginal ultrasonography.

Methods

A bodymarker system which utilizes an electromagnetic field to specify the probe position was developed. Software was written which enabled the positional information of the probe and the ultrasound image to be simultaneously displayed on a personal computer. The bodymarker was displayed as a three‐dimensional graphic model. The differences between the estimated and the actual position—i.e. the error—for both position (x, y and z) and angles (azimuth, elevation and roll) of the probe were measured. The movement of the probe was then evaluated in healthy female volunteers and the comparative time required for ultrasound examination was determined.

Results

Both the position and the angles of the probe were accurately shown in the computer display. The errors were 1.0 mm and 0.7° (median) for position and angle, respectively. The system was also shown to work well in healthy female volunteers. Calibration of the new system required only 5.0 seconds, compared with an average of 7.6 seconds for the conventional bodymarker.

Conclusion

The newly developed three‐dimensional automatic transvaginal bodymarker system provides an accurate indication of probe position and its tilting angle. It works well in healthy female volunteers and speeds up the examination time. It may be clinically useful for transvaginal ultrasound examination. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Unexpected intrauterine death following resolution of hydrops fetalis after betamethasone treatment in a fetus with a large cystic adenomatoid malformation of the lung
Authors: Leung W. C. , Ngai C. , Lam T. P. W. , Chan K. L. , Lao T. T. , Tang M. H. Y.
Published: May 2005

Without intervention, the development of hydrops fetalis secondary to cystic adenomatoid malformation of the lung (CAML) implies a 100% mortality rate. Conversely, four CAML cases with in‐utero resolution of hydrops fetalis after prenatal betamethasone therapy with good clinical outcome have been reported in the literature. The mechanism is speculated to be the effect of corticosteroid in improving lung maturation. Here we present another CAML case with resolution of hydrops fetalis after prenatal betamethasone therapy but which was followed by later intrauterine death. We speculate that the resolution of the CAML lesion itself may be more important in determining the clinical outcome than the resolution of hydrops. The association between prenatal betamethasone therapy and resolution of hydrops may be related to a different mechanism other than improvement of lung maturation. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
The equations of a viscous asymmetric fluid: An interactive approach
Authors: Rojas‐Medar M.A. , Ortega‐Torres E.E.
Published: May 2005

In this work we present a new proof of the existence and uniqueness of strong solutions for the equations of a viscous asymmetric fluids. We use an interactive approach and we prove that the approximate solutions constructed by using this method converge to a strong solution of these equations. We also give convergence‐rate bounds for this method.
Analysis and improvement of a perturbation solution for hydraulic flow in a rotating parabolic channel
Authors: Laanearu J. , Lundberg P.
Published: May 2005

Power series solutions are presented for a problem within rotating hydraulics. A variety of techniques has been used to investigate and improve the convergence of the expansions. The locations of the dominating singularities affecting the convergence properties of the perturbative series were determined using the Domb‐Sykes ratio test as well as a Padé‐approximant method. Hereafter conformal mapping and series reversion have been applied to extend the parametric range of utility of the series and to accelerate their convergence.
Open‐loop stable solutions of periodic optimal control problems in robotics
Authors: Mombaur K.D. , Bock H.G. , Schlöder J.P. , Longman R.W.
Published: May 2005

We present a numerical method that optimizes the open‐loop stability of solutions of periodic optimal control problems. We consider general periodic processes that may have several phases, each characterized by its own set of differential equations, and discontinuities of the state variables and the right hand side between phases. Stability is measured in terms of the spectral radius of the monodromy matrix which results in a nonsmooth optimization criterion. We have applied this method to design walking robots that can perform stable periodic gaits without any sensors or feedback; three such examples are presented in this paper.
On the contact reaction in a solid circular plate simply supported along an edge arc and deflected by a central transverse concentrated force
Authors: Monegato G. , Strozzi A.
Published: May 2005

A static, purely flexural mechanical analysis is presented for a Kirchhoff solid circular plate, deflected by a transverse central force, and bilaterally supported along a single periphery arc, the remaining part of the boundary being free. The contact reaction is assumed to be formed by a distributed reaction force accompanied by a distributed moment with radial axis. This plate problem is formulated in terms of an integral equation of the Prandtl type, supplemented by a vertical and a rotational equilibrium condition. It is shown that the Prandtl equation coupled to the equilibrium condition possesses a unique solution in a proper scale of weighted Sobolev‐type spaces, with certain smoothness properties, and that no solution exists if the distributed moment is absent. Finally, the behaviour of the solution at the endpoints of the support is clarified.
Effect of Treadmill Testing and Exercise Training on Self-Efficacy in Patients with Heart Failure
Authors: Oka Roberta K. , DeMarco Teresa , Haskell William L.
Published: May 2005

Background: Self-efficacy is a person's confidence in being able to successfully perform a specific activity or behavior. Self-efficacy has been shown to influence exercise capacity in patients post myocardial infarction, but has not been fully explored in patients with heart failure (HF). This study examined the impact of performance of a single treadmill exercise test and participation in a 3-month program of walking and resistance exercise on self-efficacy in HF patients.

Methods: 24 patients were randomized to either a home-based walking and resistance exercise program or usual care for 3 months. Prior to enrollment into the exercise program all participants performed a single treadmill exercise test with respiratory gas analysis. Self-efficacy questionnaires were completed at 3 time points, 1) prior to performance of an exercise treadmill test; 2) immediately after completing an exercise test; and 3) at the end of a 3-month exercise program.

Results: Self-efficacy for walking ( p = 0.07), climbing ( p = 0.17), lifting ( p = 0.73) and general activity ( p = 0.15) did not improve after performance of a single treadmill exercise test and usual care. However, self-efficacy for walking increased after 3 months of a walking and resistance exercise program. ( p = 0.04).

Conclusions: The findings from this study suggest that in patients with stable mild to moderate heart failure, self-efficacy is improved with participation in a home-based walking and endurance exercise program. Self-efficacy is not enhanced by performance of a single treadmill exercise test and usual care.
Retracted: Aspirin inhibits serine phosphorylation of insulin receptor substrate 1 in growth hormone treated animals
Authors: Prattali Raphael R. , Barreiro Guilherme C. , Caliseo Caio T. , Fugiwara Felipe Y. , Ueno Mirian , Prada Patrícia O. , Velloso Licio A. , Saad Mario J.A. , Carvalheira José B.C.
Published: May 2005

In this study, we demonstrate that pretreatment with aspirin inhibits GH‐induced insulin resistance. GH was observed to lead to serine phosphorylation of IRS‐1, a phenomenon which was reversed by aspirin in liver, muscle and WAT in parallel with a reduction in JNK activity. In addition, our data show an impairment of insulin activation in the IR/IRS/PI(3)kinase pathway and a reduction in IRS‐1 protein levels in rats treated with GH, which was also reversed in the animals pretreated with aspirin. Overall, these results provide new insights into the mechanism of GH‐induced insulin resistance.
Mitotic requirement for aurora A kinase is bypassed in the absence of aurora B kinase
Authors: Yang Hui , Burke Teresa , Dempsey Jack , Diaz Bruce , Collins Elizabeth , Toth John , Beckmann Richard , Ye Xiang
Published: May 2005

We investigated why treatment of cells with dual aurora A and B kinase inhibitors produces phenotypes identical to inactivation of aurora B. We found that dual aurora kinase inhibitors in fact potently inhibit cellular activities of both kinases, indicating that inactivation of aurora B bypasses aurora A in mitosis. RNAi experiments further established that inactivation of aurora B indeed bypasses the requirement for aurora A and leads to polyploidy. Inactivation of aurora A activates checkpoint kinase BubR1 in an aurora B‐dependent manner. Our results thus show that aurora B is responsible for mitotic arrest in the absence of aurora A.