bluuebunny/crossref_metadata_2025 huggingface dataset:
Biodegradable poly(ester amine) based on glycerol dimethacrylate and polyethylenimine as a gene carrier
Authors: Arote Rohidas B. , Hwang Soon‐Kyung , Yoo Mi‐Kyong , Jere Dhananjay , Jiang Hu‐Lin , Kim You‐Kyoung , Choi Yun‐Jai , Nah Jae‐Woon , Cho Myung‐Haing , Cho Chong‐Su
Published: September 2008

Background

Polyethylenimine (PEI) vectors are widely used in gene delivery because of their high transfection efficiency owing to a unique proton sponge effect. An increase in molecular weight increases transfection efficiency, but simultaneously results in increased toxicity. Therefore, the design and synthesis of new degradable gene delivery carriers having high transfection efficiencies and reduced cytotoxicity are necessary.

Methods

In the present study degradable poly(ester amines) (PEAs) based on glycerol dimethacrylate (GDM) and low molecular weight branched polyethylenimine (LMW‐PEI) were synthesized in anhydrous methanol at 60 °C following Michael addition reaction. The transfection efficiencies of the synthesized PEA/DNA complexes were evaluated using three different cell lines (HeLa, HepG2 and 293T cells) in vitro.

Results

PEAs with zeta potential in the range of 30–55 mV (at physiological pH) condensed plasmid DNA into nanosized particles (<150 nm) suitable for intracellular delivery. The PEAs degraded in a controlled fashion (t1/2 of approximately 9–10 days). Compared with PEI 25K, the PEAs showed significantly lower cytotoxicity in three different cells. The PEAs demonstrated much higher transfection efficiency compared to conventional PEI 25K and Lipofectamine. The PEA synthesized using a 1 : 4 mole ratio of GDM to PEI [GDM/PEI‐1.2 (1 : 4)] showed the highest transfection efficiency in HepG2 cells. Significantly higher pEGFP‐N2 reporter gene expression in 293T cells was achieved using these PEAs. The hyperosmotic effect of PEAs was demonstrated by the reduction in packed cell volume (PCV). The GDM/PEI‐1.2 (1 : 4) showed comparable reduction in PCV with respect to glycerol in 293T cells. The effect of bafilomycin A1 on transfection efficiency of PEAs on 293T cells indicated its endosomal buffering capacity.

Conclusions

We hypothesized that the higher transfection efficiency of PEAs was the synergistic effect arising from hyperosmotic glycerol and endosomal buffering capacity of PEAs resulting from the presence of a glycerol backbone and PEI amine groups, respectively. Copyright © 2008 John Wiley & Sons, Ltd.
Morphometric and ultrastructural comparison of the olfactory system in elasmobranchs: The significance of structure–function relationships based on phylogeny and ecology
Authors: Schluessel Vera , Bennett Michael B. , Bleckmann Horst , Blomberg Simon , Collin Shaun P.
Published: September 2008

This study investigated the relationship between olfactory morphology, habitat occupancy, and lifestyle in 21 elasmobranch species in a phylogenetic context. Four measures of olfactory capability, that is, the number of olfactory lamellae, the surface area of the olfactory epithelium, the mass of the olfactory bulb, and the mass of the olfactory rosette were compared between individual species and groups, comprised of species with similar habitat and/or lifestyle. Statistical analyses using generalized least squares phylogenetic regression revealed that bentho‐pelagic sharks and rays possess significantly more olfactory lamellae and larger sensory epithelial surface areas than benthic species. There was no significant correlation between either olfactory bulb or rosette mass and habitat type. There was also no significant difference between the number of lamellae or the size of the sensory surface area in groups comprised of species with similar diets, that is, groups preying predominantly on crustaceans, cephalopods, echinoderms, polychaetes, molluscs, or teleosts. However, some groups had significantly larger olfactory bulb or rosette masses than others. There was little evidence to support a correlation between phylogeny and morphology, indicating that differences in olfactory capabilities are the result of functional rather than phylogenetic adaptations. All olfactory epithelia exhibited microvilli and cilia, with microvilli in both nonsensory and sensory areas, and cilia only in sensory areas. Cilia over the sensory epithelia originated from supporting cells. In contrast to teleosts, which possess ciliated and microvillous olfactory receptor types, no ciliated olfactory receptor cells were observed. This is the first comprehensive study comparing olfactory morphology to several aspects of elasmobranch ecology in a phylogenetic context. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
Qucs: A GPL software package for circuit simulation, compact device modelling and circuit macromodelling from DC to RF and beyond
Authors: Brinson M. E. , Jahn S.
Published: September 2008

The ‘Quite universal circuit simulator’ (Qucs) is an open source circuit simulator supporting Verilog‐A compact model standardization. This paper describes a number of compact semiconductor device and circuit macromodelling techniques that have been implemented in recent Qucs releases, stressing those techniques that are not found in SPICE 2g6 or 3f5. It also introduces a novel hierarchical approach to Verilog‐A compact model and circuit macromodel construction based on non‐linear equation‐defined devices, linear‐controlled sources and noise generators embedded in subcircuits. To illustrate the new approach, the properties and models of a number of components with electrical and non‐electrical characteristics are described. These models demonstrate how recent trends in open source simulation technology use embedded equations as integral elements in component and physical process models. Copyright © 2008 John Wiley & Sons, Ltd.
Liquid–liquid–liquid microextraction followed by HPLC with UV detection for quantitation of ephedrine in urine
Authors: Bagheri Habib , Khalilian Faezeh , Ahangar Laleh Enayati
Published: September 2008

Liquid–liquid–liquid microextraction (LLLME) in combination with HPLC and UV detection has been used as a sensitive method for the determination of ephedrine in urine samples. Extraction process was performed in a homemade total glass vial without using a Teflon ring, usually employed. Ephedrine was first extracted from 3.5 mL of urine sample (pH 12) into a microfilm of toluene/benzene (50:50). The analyte was subsequently back extracted into an acidic microdrop solution (pH 2) suspended in the organic phase. The extract was then injected into the HPLC system directly. An enrichment factor of 137 along with a good sample clean‐up was obtained under the optimized conditions. The calibration curve showed linearity in the range of 0.01–50 mg/L with regression coefficient corresponding to 0.998. The LODs and LOQs, based on a S/N of 3 and 10, were 5 and 10 μg/L, respectively. The method was eventually applied for the determination of ephedrine in urine sample after oral administration of 5 mg single dose of drug.
Vitrification during the Isothermal Cure of Thermosets: Comparison of Theoretical Simulations with Temperature‐Modulated DSC and Dielectric Analysis
Authors: Fraga Iria , Montserrat Salvador , Hutchinson John M.
Published: September 2008

Vitrification during the isothermal cure of a thermoset, which is monitored by dynamic techniques such as temperature‐modulated differential scanning calorimetry (TMDSC) or dielectric analysis (DEA), is analyzed in terms of its dependence on frequency. A simulation was used to obtain the vitrification time as a function of frequency, considering it as the time when the (frequency‐dependent) glass transition temperature, Tg, of the curing system reaches the cure temperature. Simulations were carried out at different cure temperatures. Other parameters, such as the exponents (reaction orders) in the Kamal equation, λ in the DiBenedetto equation (controlling the dependence of Tg on the degree of cure), and the activation energy for the frequency dependence of Tg, were also considered. The results are compared with those obtained experimentally by a TMDSC technique at low frequencies and by DEA at high frequencies. From the simulations it is found that the vitrification time decreases nonlinearly with log(frequency) in the low frequency range but approaches a linear dependence at high frequencies, in agreement with experimental data.

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Factor analysis reveals differences in brain metabolism in macaques with SIV/AIDS and those with SIV‐induced encephalitis
Authors: Lentz Margaret R. , Lee Vallent , Westmoreland Susan V. , Ratai Eva‐Maria , Halpern Elkan F. , González R. Gilberto
Published: September 2008

MRS has often been used to study metabolic processes in the HIV‐infected brain. However, it remains unclear how changes in individual metabolites are related to one another in this context of virus‐induced central nervous system dysfunction. We used factor analysis (FA) to identify patterns of metabolite distributions from an MRS study of healthy macaques and those infected with simian immunodeficiency virus (SIV) which were moribund with AIDS. FA summarized the correlations from nine metabolites into three main factors. Factor 3 identified patterns that discern healthy animals from those with SIV/AIDS. Factor 2 was able to differentiate between animals that had encephalitis and those moribund with AIDS but lacking encephalitis. Specifically, Factor 2 was able to distinguish animals with moderate to severe encephalitis from animals with mild or no encephalitis as well as uninfected controls. FA not only confirmed the involvement of neuronal metabolites (N‐acetylaspartate and glutamate) in disease severity, but also detected changes in creatine and myo‐inositol that have not been observed in the SIV macaque model previously. These results suggest that the divergent pathways of N‐acetylaspartate and creatine in this disease may enable the commonly reported ratio N‐acetylaspartate/creatine to be a more sensitive marker of disease severity. Copyright © 2008 John Wiley & Sons, Ltd.
Properties of discrete Chebyshev collocation differential operators in curvilinear geometries
Authors: Pironkov P. , Schäfer M. , Krastev K.
Published: September 2008

The properties of discrete systems resulting from spectral Chebyshev collocation discretizations are investigated with respect to the solution efficiency of corresponding solvers. Complex geometries are encountered by a mapping technique to connect computational and physical domains. Several representative transformation techniques are considered. The influences of the differential operators, the boundary conditions, the geometry, and the number of grid points are systematically studied. The convergence properties of the BiCGSTAB method when iteratively solving the discrete systems are investigated. Copyright © 2008 John Wiley & Sons, Ltd.
On the weighted dyadic diaphony of digital (t, s)‐sequences
Authors: Kritzer Peter , Pillichshammer Friedrich
Published: September 2008

In this note, we present results on the weighted dyadic diaphony of digital (t, s)‐sequences over ℤ2. These results are closely linked to the worst‐case error for quasi‐Monte Carlo integration in certain spaces of functions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On freezing of a finite humid porous medium with a heat flux condition considering the factor for phase conversion
Authors: Marcus Eduardo A. Santillan
Published: September 2008

This work deals with a theoretical mathematical analysis of freezing (desublimation) of moisture in a finite porous medium with heat‐flux condition in x=0. The position of phase change front at time t, given by x =s (t), divides the porous body into two regions. In the first region there is no moisture movement, and in the other one the process of the coupled heat and moisture flows is described by the well known Luikov's system, considering that the factor for phase conversion is non zero. Equivalence between this problem and a system of Volterra integral equations is found. The existence of a unique local solution in time for this problem is also obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Symmetry and bifurcation in vestibular system
Authors: Golubitsky Marty , Shiau LieJune , Stewart Ian
Published: September 2008

The vestibular system in almost all vertebrates, humans included, controls balance by employing a set of six semicircular canals, three in each inner ear, to detect angular accelerations of the head. Signals from the canals are transmitted to neck motoneurons and activate eight corresponding muscle groups. These signals may be either excitatory or inhibitory, depending on the direction of acceleration. McCollum and Boyle have observed that in the cat the network of neurons concerned possesses octahedral symmetry, a structure deduced from the known innervation patterns (connections) from canals to muscles.

We re‐derive the octahedral symmetry from mathematical features of the probable network architecture, and model the movement of the head in response to the activation patterns of the muscles concerned. We assume that connections among neck muscles can be modeled by a ‘coupled cell network’, a system of coupled ODEs whose variables correspond to the eight muscles, and that network also has octahedral symmetry. The network and its symmetries imply that these ODEs must be equivariant under a suitable action of the octahedral group.

Using results of Ashwin and Podvigina, we show that with the appropriate group actions, there are six possible spatiotemporal patterns of time‐periodic states that can arise by Hopf bifurcation from an equilibrium corresponding to natural head motions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new 11 point degree 6 cubature formula for the triangle
Authors: Day David M. , Taylor Mark A.
Published: September 2008

We present a new cubature formula in the triangle which exactly integrates polynomials up to degree 6, using only 11 points. The formula was computed by starting with a 12 point cubature formula and applying the reduced basis method to drive one of the weights to zero, resulting in an 11 point formula with positive weights and no points outside the triangle. This improves upon the previously best known positive inside formulas, which have 12 or more points. The lower bound on the number of points for a degree 6 cubature formula in the triangle is 10, which to date has only been obtained by allowing some of the points to be outside the triangle. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect‐based a‐posteriori error estimation for differential‐algebraic equations
Authors: Auzinger W. , Lehner H. , Weinmüller E.
Published: September 2008

We show how the QDeC estimator, an efficient and asymptotically correct a‐posteriori error estimator for collocation solutions to ODE systems, can be extended to differential‐algebraic equations of index 1. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Membrane and membrane‐associated proteins involved in the aggressive phenotype displayed by highly invasive cancer cells
Authors: Dowling Paul , Walsh Naomi , Clynes Martin
Published: September 2008

Invasion, the penetration of tumour cells into adjacent tissues, is a fundamental characteristic of malignant carcinomas and a first step in the metastatic process. The molecular mechanisms involved in tumour cell invasion are complex, but over the last couple of decades the knowledge base has grown quite considerably and many proteins with important roles in invasion have been identified and characterised. Benign tumours typically are encapsulated, which inhibits their ability to behave in a malignant manner, meaning these tumours do not grow in a location‐limited less aggressive manner, do not invade surrounding tissues and do not metastasise. The ability of malignant tumours to invade and metastasise is the major cause of death for cancer patients. A greater insight into the molecular basis of cancer invasion and metastasis will lead to the development of novel therapies and specific panels of biomarkers for use in the treatment and diagnosis/monitoring in many types of metastatic cancer.
Sub‐cellular localization of membrane proteins
Authors: Sadowski Pawel G. , Groen Arnoud J. , Dupree Paul , Lilley Kathryn S.
Published: September 2008

In eukaryotes, numerous complex sub‐cellular structures exist. The majority of these are delineated by membranes. Many proteins are trafficked to these in order to be able to carry out their correct physiological function. Assigning the sub‐cellular location of a protein is of paramount importance to biologists in the elucidation of its role and in the refinement of knowledge of cellular processes by tracing certain activities to specific organelles. Membrane proteins are a key set of proteins as these form part of the boundary of the organelles and represent many important functions such as transporters, receptors, and trafficking. They are, however, some of the most challenging proteins to work with due to poor solubility, a wide concentration range within the cell and inaccessibility to many of the tools employed in proteomics studies. This review focuses on membrane proteins with particular emphasis on sub‐cellular localization in terms of methodologies that can be used to determine the accurate location of membrane proteins to organelles. We also discuss what is known about the membrane protein cohorts of major organelles.
Bacterial membrane proteomics
Authors: Poetsch Ansgar , Wolters Dirk
Published: September 2008

About one quarter to one third of all bacterial genes encode proteins of the inner or outer bacterial membrane. These proteins perform essential physiological functions, such as the import or export of metabolites, the homeostasis of metal ions, the extrusion of toxic substances or antibiotics, and the generation or conversion of energy. The last years have witnessed completion of a plethora of whole‐genome sequences of bacteria important for biotechnology or medicine, which is the foundation for proteome and other functional genome analyses. In this review, we discuss the challenges in membrane proteome analysis, starting from sample preparation and leading to MS‐data analysis and quantification. The current state of available proteomics technologies as well as their advantages and disadvantages will be described with a focus on shotgun proteomics. Then, we will briefly introduce the most abundant proteins and protein families present in bacterial membranes before bacterial membrane proteomics studies of the last years will be presented. It will be shown how these works enlarged our knowledge about the physiological adaptations that take place in bacteria during fine chemical production, bioremediation, protein overexpression, and during infections. Furthermore, several examples from literature demonstrate the suitability of membrane proteomics for the identification of antigens and different pathogenic strains, as well as the elucidation of membrane protein structure and function.
The AOHUPO Membrane Proteomics Initiative, Fourth Workshop 22 June 2008, Cairns, Australia
Authors: Chung Maxey , Nakamura Kazuyuki , Jordan T. William
Published: September 2008

The Fourth Asia Oceania Human Proteome Organisation Membrane Proteomics Initiative (AOHUPO MPI) Workshop took place on 22 June 2008 in Cairns, Australia, with approximately 90 attendees from academia and industry. Participants from ten of the seventeen collaborating centres presented workshop papers. This was part of the pre‐conference programme of the Joint Fourth Asian Oceania Human Proteome Organisation Conference and the Second Pacific Rim International Conference on Protein Structure.
Kekulé pattern on conductance images between two STM probes
Authors: Nakanishi Takeshi , Ando Tsuneya
Published: September 2008

The conductance image between two probes of scanning‐tunneling‐microscopy (STM) is calculated in a zigzag carbon nanotube within a tight‐binding model and a realistic model for STM probes. A Kekulé‐type pattern usually appears due to interference of states at K and K' points. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time dependent growth of vertically aligned carbon nanotube forest using a laser activated catalytical CVD method
Authors: Haluška Miro , Bellouard Yves , Dietzel Andreas
Published: September 2008

We report the growth of vertically aligned single‐wall and multi‐wall carbon nanotube forest using a Laser Activated – Catalytic Chemical Vapor Deposition process. The experiments were performed in a cold‐wall reactor filled with an ethylene‐hydrogen‐argon gas mixture in a 5:2:8 ratio at ambient pressure. A near infrared continuous wave laser diode was focused on a flat specimen to promote a local carbon nanotubes growth. Si substrates coated with a 20 nm Al2O3 layer on which a 2 nm thick Fe film was deposited were used. Growth products are characterized using Raman spectroscopy and Scanning Electron Microscopy. In this paper, we specifically discuss the influence of the laser exposure time on the growth process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kondo effects in a C60 single‐molecule transistor
Authors: Roch N. , Winkelmann C. B. , Florens S. , Bouchiat V. , Wernsdorfer W. , Balestro F.
Published: September 2008

We have used the electromigration technique to fabricate a C60 single‐molecule transistor (SMT).We present a full experimental study as a function of temperature, down to 35 mK, and as a function of magnetic field up to 8 T in a SMT with odd number of electrons, where the usual spin‐1/2 Kondo effect occurs, with good agreement with theory. In the case of even number of electrons, a low temperature magneto‐transport study is provided, which demonstrates a Zeeman splitting of the zero‐bias anomaly at energies well below the Kondo scale. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical properties of C4+ irradiated single‐walled carbon nanotube paper
Authors: Skákalová Viera , Kaiser Alan B. , Dettlaff Ursula , Arstila Kai , Krasheninnikov Arkady V. , Keinonen Juhani , Roth Siegmar
Published: September 2008

Single‐walled carbon nanotube (SWNT) networks have been irradiated with a 12C4+ ion beam (ion energy 23 MeV) to investigate changes to their properties. Measurements of the Raman D‐line show that the irradiation produces structural defects throughout SWNT paper of thickness 40 μm, with a linear increase in defects at the back side of the sample, but a saturating tendency occurring at the front (irradiated) side. The resistance of the samples also increases linearly with irradiation dose. The temperature dependence of the conductivity of the samples is changed progressively by the irradiation: whereas the pristine sample exhibits mixed metallic‐nonmetallic character consistent with the usual model of metallic conduction interrupted by thin barriers through which fluctuation‐assisted tunnelling occurs, the temperature dependence loses its metallic character and follows three‐dimensional variable‐range hopping for the most irradiated sample. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silicon‐doping induced strain of AlN layers: a comparative luminescence and Raman study
Authors: Prinz Günther M. , Feneberg Martin , Schirra Martin , Sauer Rolf , Thonke Klaus , Thapa Sarad B. , Scholz Ferdinand
Published: September 2008

Si‐doped aluminum nitride layers show a shift of the near‐band‐edge luminescence at around 6 eV to lower energies for increasing Si concentration up to ≈(1–3) × 1019 cm–3. For higher concentrations, the luminescence shifts back to higher energies. This behavior is compared to concomitant shifts of the Raman‐active E2 vibrational mode and to X‐ray diffraction data. It can be explained in terms of increasing tensile strain which finally relaxes due to the formation of cracks. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ZnO nanowall networks grown on DiMPLA pre‐patterned thin gold films
Authors: Mäder M. , Gerlach J. W. , Höche T. , Czekalla C. , Lorenz M. , Grundmann M. , Rauschenbach B.
Published: September 2008

ZnO nanowall networks grown by a high pressure pulsed laser deposition (PLD) technique on a pre‐patterned thin gold film are presented. The thin gold film on a c ‐plane oriented sapphire substrate was structured with diffraction mask projection laser ablation (DiMPLA). It is shown that only areas processed with the laser patterning technique reveal homogeneous growth of ZnO nanowall networks. Photoluminescence measurements prove the higher material quality of the pre‐patterned regions compared to the untreated ones. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantification of 19‐nortestosterone sulphate and boldenone sulphate in urine from male horses using liquid chromatography/tandem mass spectrometry
Authors: Grace Philip B. , Drake Erica C. , Teale Philip , Houghton Edward
Published: September 2008

Following administration of the anabolic steroid 19‐nortestosterone or its esters to the horse, a major urinary metabolite is 19‐nortestosterone‐17β‐sulphate. The detection of 19‐nortestosterone in urine from untreated animals has led to it being considered a naturally occurring steroid in the male horse. Recently, we have demonstrated that the majority of the 19‐nortestosterone found in extracts of ‘normal’ urine from male horses arises as an artefact through decarboxylation of the 19‐carboxylic acid of testosterone. The aim of this investigation was to establish if direct analysis of 19‐nortestosterone‐17β‐sulphate by liquid chromatography/tandem mass spectrometry (LC/MS/MS) had potential for the detection of 19‐nortestosterone misuse in the male horse. The high concentrations of sulphate conjugates of the female sex hormones naturally present in male equine urine were overcome by selective hydrolysis of the aryl sulphates using glucuronidase from Helix pomatia; this was shown to have little or no activity for alkyl sulphates such as 19‐nortestosterone‐17β‐sulphate. The ‘free’ phenolic steroids were removed by solid‐phase extraction (SPE) prior to LC/MS/MS analysis. The method also allowed for the quantification of the sulphate conjugate of boldenone, a further anabolic steroid endogenous in the male equine with potential for abuse in sports. The method was applied to the quantification of these analytes in a population of samples. This paper reports the results of that study along with the development and validation of the LC/MS/MS method. The results indicate that while 19‐nortestosterone‐17β‐sulphate is present at low levels as an endogenous substance in urine from ‘normal’ male horses, its use as an effective threshold substance may be viable. Copyright © 2008 John Wiley & Sons, Ltd.
Analysis of non‐enzymatically glycated peptides: neutral‐loss‐triggered MS3 versus multi‐stage activation tandem mass spectrometry
Authors: Zhang Qibin , Petyuk Vladislav A. , Schepmoes Athena A. , Orton Daniel J. , Monroe Matthew E. , Yang Feng , Smith Richard D. , Metz Thomas O.
Published: September 2008

Non‐enzymatic glycation of tissue proteins has important implications in the development of complications of diabetes mellitus. While electron transfer dissociation (ETD) has been shown to outperform collision‐induced dissociation (CID) in sequencing glycated peptides by tandem mass spectrometry, ETD instrumentation is not yet widely available and often suffers from significantly lower sensitivity than CID. In this study, we evaluated different advanced CID techniques (i.e., neutral‐loss‐triggered MS3 and multi‐stage activation) during liquid chromatography/multi‐stage mass spectrometric (LC/MSn) analyses of Amadori‐modified peptides enriched from human serum glycated in vitro. During neutral‐loss‐triggered MS3 experiments, MS3 scans triggered by neutral losses of 3 H2O or 3 H2O + HCHO produced similar results in terms of glycated peptide identifications. However, neutral losses of 3 H2O resulted in significantly more glycated peptide identifications during multi‐stage activation experiments. Overall, the multi‐stage activation approach produced more glycated peptide identifications, while the neutral‐loss‐triggered MS3 approach resulted in much higher specificity. Both techniques are viable alternatives to ETD for identifying glycated peptides. Copyright © 2008 John Wiley & Sons, Ltd.
Single drop microextraction using silver nanoparticles as electrostatic probes for peptide analysis in atmospheric pressure matrix‐assisted laser desorption/ionization mass spectrometry and comparison with gold electrostatic probes and silver hydrophobic probes
Authors: Sudhir Putty‐Reddy , Shrivas Kamlesh , Zhou Zi‐Cong , Wu Hui‐Fen
Published: September 2008

Single drop microextraction using tetraalkylammonium bromide coated silver nanoparticles (SDME‐AgNPs) prepared in toluene has been successfully applied as electrostatic affinity probes to preconcentrate peptide mixtures in biological samples prior to atmospheric pressure matrix‐assisted laser desorption/ionization ion trap mass spectrometry (AP‐MALDI‐MS) analysis. This approach is based on the isoelectric point (pI) of peptides and surface charge of AgNPs. Using the SDME‐AgNPs technique, from a peptide mixture, Met‐ and Leu‐enkephalins (Met‐enk and Leu‐enk) were extracted into a droplet of toluene containing AgNPs, but not the neutral peptides (gramicidins). The best peptide extraction efficiency for SDME‐AgNPs was observed with the optimized parameters: extraction time 2 min, sample agitation rate 240 rpm, and sample pH 7. The limits of detection (LODs) of the SDME‐AgNPs/AP‐MALDI‐MS technique for Met‐enk and Leu‐enk peptides were 160 and 210 nM, respectively. Furthermore, the application of the technique has been shown for the analysis of peptides from a sample containing high matrix interferences such as 1% Triton X‐100 and 6 M urea. Finally, this approach has been compared with the SDME‐AuNPs technique and the results have clearly revealed that the SDME‐AgNP affinity probe exhibits higher affinity to extract the sulfur‐bearing peptide (Met‐enk). We also compared this electrostatic affinity probe of AgNPs with the previously demonstrated hydrophobic affinity probe of AgNPs and found that the electrostatic probe can greatly reduce the extraction time from 1.5 h to 2 min. This is due to the fact that electrostatic attraction forces are much stronger than the hydrophobic attraction forces. Therefore, we concluded that the electrostatic affinity probe based on SDME‐AgNPs coupled with AP‐MALDI‐MS is a high‐throughput technique for the analysis of low‐abundance peptides from biological samples containing complex matrices. Copyright © 2008 John Wiley & Sons, Ltd.
Robotic intercostal nerve graft for reversal of thoracic sympathectomy: a large animal feasibility model
Authors: Latif M. J. , Afthinos J. N. , Connery C. P. , Perin N. , Bhora F. Y. , Chwajol M. , Todd G. J. , Belsley S. J.
Published: September 2008

Background

A subset of patients who undergo video‐assisted thoracoscopic sympathectomy for hyperhydrosis develop post‐procedure compensatory sweating that is perceived as more debilitating than their initial complaints. We propose a novel treatment to reverse sympathectomy by implantation of an intercostal nerve graft using the da Vinci robot.

Methods

A robotic swine model was established using single‐lung ventilation and four ports. The pleura was incised and a representative segment of sympathetic chain was transected. A nearby intercostal nerve was harvested and sutured to the sympathetic chain using four interrupted 10‐0 nylon sutures on the epineurium.

Results

The intercostal nerve was an excellent size match and post‐procedure necropsy yielded successful anastomoses without apparent complications.

Conclusions

Robotic intercostal nerve grafting for reversal of thoracic sympathectomy is technically feasible. The robotic device allows the principles of neural microsurgery to be maintained and provides a minimally invasive option for reconstruction of the sympathetic chain. Copyright © 2008 John Wiley & Sons, Ltd.
A client‐based vertical handoff approach for seamless mobility across heterogeneous wireless networks
Authors: Kim Yong‐Sung , Kwon Dong‐Hee , Suh Young‐Joo
Published: September 2008

With the rapid growth of mobile Internet, offering seamless connectivity in different types of wireless networks is an important feature in next generation wireless networks (4G networks). Mobile IP (MIP) is expected to play a key role to handle the movements of mobile nodes (MNs) in 4G networks. However, MIP suffers from long handoff latency since it is designed to support the macromobility of a MN. Therefore, it is necessary to devise a scheme that provides currently deployed networks with backward compatibility and that offers seamless connectivity during MIP handoffs across the heterogeneous wireless networks. In this paper, we propose a client‐based vertical handoff system for multi‐networks to provide end‐users with seamless connectivity across heterogeneous wireless networks. Our proposed system is designed as a common network interface at a client side and provides transparent service to IP/MIP layers regardless of used wireless technologies. With this system, we also present vertical handoff performance over a loosely coupled cdma2000/WLAN experimental test‐bed. The experimental results show that our system enables a MN to handoff seamlessly across different types of wireless networks without any modifications to the existing IP/MIP stack and core network. Copyright © 2008 John Wiley & Sons, Ltd.
On the enhancements to IEEE 802.11 MAC and their suitability for safety‐critical applications in VANET
Authors: Chen Xianbo , Refai Hazem H. , Ma Xiaomin
Published: September 2008

Vehicular ad hoc network (VANET) or inter‐vehicle communication (IVC) provides many brand new and powerful capabilities for transportation system applications. Safety massaging, as one of the capabilities, supports many potential safety applications such as emergency electronic brake lights, lane change warning, pre‐crash warning. These applications require a low latency and high reliability communication service. In this paper, we first analyze these critical requirements. The under‐development 802.11p for VANET is then discussed with respect to those requirements. An extensive research on the enhancements for 802.11 media access control (MAC) is conducted in order to show their suitability for safety applications. As a conclusion, a realistically feasible MAC enhancement scheme is still needed to achieve the high performance requirements and the compatibility. Copyright © 2008 John Wiley & Sons, Ltd.
A Proactive mobile‐initiated fast handoff scheme using the multihomed approach
Authors: Huang Chung‐Ming , Chiang Meng‐Shu , Lin Chin‐Wei
Published: September 2008

Mobile IP (MIP) defines a mobility management for mobile users to continuously access data when the currently attachment is changed to another network. However, when mobile node (MN) roams between network segments, the handoff latency results in packet losses and transmission delay. In this paper, we propose a multihomed fast handoff scheme (MFH‐MIP) to decrease the handoff cost. In the proposed MFH‐MIP scheme, each MN is implemeted with the link layer trigger and multihomed techniques. Based on the link layer trigger, MN can collect signal strengths of nearby access points (APs) and switch to a new link automatically when the old link becomes unsuitable to connect. Using the multihomed technique, MN can prepare for handoff using two (or more) interfaces, in which (i) one is connected with the old link to receive packets and (ii) the other one is used to access nearby APs and select the most suitable one as the new link, in parellel. In this way, MN can continuously transmit and receive packets during handoff. Based on the proposed method, MN can roam smoothly among different networks in the wireless environment. Copyright © 2008 John Wiley & Sons, Ltd.
Monitoring feed amounts in goliath groupers (Epinephelus itajara) using behavioral conditioning in a large mixed species exhibit
Authors: Kittell Michele M. , Ratte Magan E.
Published: September 2008

Goliath groupers (Epinephelus itajara) are large charismatic species, which are often residents in public aquaria. This study reports a novel approach to feeding techniques for three resident goliath groupers. Because of the size and depth of their exhibit, the groupers were conditioned to hand feed from aquarists. Daily food logs were recorded including the type and number of species, how often the groupers were fed, and how often they accepted the offered food. Mackerel, herring, and sardine represented the highest percentage of the diet, whereas capelin, squid, and shrimp were the lowest percentage. Over a one‐year period, records showed that grouper 1 and grouper 3 ate fairly consistently throughout the year. Grouper 2 had a higher degree of variation in his monthly feeding average with a decrease from May to September and an increase through April. Grouper 1 and grouper 3 took food from the aquarists most consistently with a monthly average of 88.8±10.8 and 89.7±6.15% of the time, respectively. Grouper 2 was not as consistent, hand feeding at only 74.5±16.2% of the time offered. Diet management and behavioral conditioning with the goliath groupers have established consistent husbandry records and therefore better monitoring of the individual fish's long‐term health status. Zoo Biol 27:414–419, 2008. © 2008 Wiley‐Liss, Inc.
Regularized Finite Mixture Models for Probability Trajectories
Authors: Shedden Kerby , Zucker Robert A.
Published: September 2008

Finite mixture models are widely used in the analysis of growth trajectory data to discover subgroups of individuals exhibiting similar patterns of behavior over time. In practice, trajectories are usually modeled as polynomials, which may fail to capture important features of the longitudinal pattern. Focusing on dichotomous response measures, we propose a likelihood penalization approach for parameter estimation that is able to capture a variety of nonlinear class mean trajectory shapes with higher precision than maximum likelihood estimates. We show how parameter estimation and inference for whether trajectories are time-invariant, linear time-varying, or nonlinear time-varying can be carried out for such models. To illustrate the method, we use simulation studies and data from a long-term longitudinal study of children at high risk for substance abuse.
Acute tibial tubercle avulsion fractures in children: Selective use of the closed reduction and internal fixation method
Authors: Pesl Tomas , Havranek Petr
Published: September 2008

Purpose

Acute tibial tubercle avulsion fractures typically occur in adolescent boys involved in certain sports. All of the excerpted authors recommend open reduction and internal fixation (ORIF) as the only method to manage the displaced form of the injury. We attempted to select the optimal medical treatment of various types of this injury. The closed reduction and internal fixation (CRIF) method was selectively used.

Methods

During a period of 10 years (1997–2006), we treated 12 children with an acute injury to the tibial tubercle. Ogden's classification was used to describe the type of injury. Nine patients with a displaced fracture were treated surgically, using either the CRIF or ORIF methods. In cases of intraarticular fracture, the use of the CRIF method was tested. The suitability of the CRIF method was decided during manipulation of the fragments under an X-ray amplifier.

Results

According to Ogden's classification, three children were classified with type 1A, one with 1B, three with 2A, four with 3A, and one with 3B. In patients with the displaced extraarticular injury (types 1B and 2A), the ORIF method of treatment was necessary. In all but one case of intraarticular fracture (type 3A and 3B), the CRIF method was sufficient.

Conclusions

The authors recommend that, for displaced intraarticular Ogden's type 3A or 3B fracture, the CRIF method should be considered as a first choice.
A Gersten-Witt complex for hermitian Witt groups of coherent algebras over schemes II: Involution of the second kind
Authors: Gille Stefan
Published: September 2008

Let X be a regular noetherian scheme of finite Krull dimension with involution σ and an Azumaya algebra over X with involution τ of the second kind with respect to σ. We construct a hermitian and a skew-hermitian Gersten-Witt complex for (, τ) and show that these complexes are exact if X = Spec R is the spectrum of a regular semilocal ring R of geometric type, such that R is a quadratic étale extension of the fixed ring of σ.
Physiological and morphological effects of genistein against the liver fluke,Fasciola hepatica
Authors: TONER E. , BRENNAN G. P. , WELLS K. , McGEOWN J. G. , FAIRWEATHER I.
Published: September 2008

A study has been carried out to determine the activity of genistein against adult liver fluke,Fasciola hepatica. Flukes were incubatedin vitroin genistein at a concentration of 0·27 mg/ml (=1 mm). They ceased to move after 3 h, at which point the experiment was terminated and the specimens prepared for examination by scanning and transmission electron microscopy. Surface changes to the flukes comprised swelling and blebbing, especially in the posterior region of the flukes, and there was particular disruption to the spines, accompanied by some spine loss. Fine structural changes to the tegumental syncytium indicated an accelerated release of secretory bodies at the surface, but a reduction in their production within the cell bodies. Autophagic activity was evident in the tegumental cells, a phenomenon that was also observed in the gastrodermal cells. Disruption to the testis and vitelline follicles was severe, with an apparent block in the normal developmental sequence of the spermatogenic and vitelline cells, respectively. Shell protein production by the vitelline cells was also disrupted. In separate experiments, somatic muscle strips were exposed to concentrations of genistein ranging from 1 μmto 1 mm. There were statistically significant increases in the frequency and/or amplitude of muscle contractions at concentrations of 10 μm, 100 μmand 1 mm. The results suggest that genistein is capable of causing severe morphological and neuromuscular disruption to adult flukesin vitroover a short time-span.
Cytosolic glutathione S-transferases ofOesophagostomum dentatum
Authors: JOACHIM A. , RUTTKOWSKI B.
Published: September 2008

Oesophagostomum dentatumstages were investigated for glutathione S-transferase (GST) expression at the protein and mRNA levels. GST activity was detected in all stages (infectious and parasitic stages including third- and fourth-stage larvae of different ages as well as males and females) and could be dose-dependently inhibited with sulfobromophthalein (SBP). Addition of SBP toin vitrolarval cultures reversibly inhibited development from third- to fourth-stage larvae. Two glutathione-affinity purified proteins (23 and 25 kDa) were detected in lysates of exsheathed third-stage larvae by SDS-PAGE. PCR-primers were designed based on peptide sequences and conserved GST sequences of other nematodes for complete cDNA sequences (621 and 624 nt) of 2 isoforms, Od-GST1 and Od-GST2, with 72% nucleotide similarity and 75% for the deduced proteins. Genomic sequences consisted of 7 exons and 6 introns spanning 1296 bp for Od-GST1 and 1579 and 1606 bp for Od-GST2. Quantitative real-time-PCR revealed considerably elevated levels of Od-GST1 in the early parasitic stages and slightly reduced levels of Od-GST2 in male worms. Both Od-GSTs were most similar to GST ofAncylostoma caninum(nucleotides: 73 and 70%; amino acids: 80 and 73%). The first three exons (75 amino acids) corresponded to a synthetic prostaglandin D2synthase (53% similarity).O. dentatumGSTs might be involved in intrinsic metabolic pathways which could play a role both in nematode physiology and in host-parasite interactions.
Verbal, visual, and spatial working memory demands during text composition
Authors: OLIVE THIERRY , KELLOGG RONALD T. , PIOLAT ANNIE
Published: September 2008

Two experiments examined whether text composition engages verbal, visual, and spatial working memory to different degrees. In Experiment 1, undergraduate students composed by longhand a persuasive text while performing a verbal, visual, or spatial concurrent task that was presented visually. In Experiment 2, participants performed a verbal or spatial concurrent task that was aurally presented. Writing performance was not disrupted differentially across the three tasks. Performance on all concurrent tasks showed fewer correct responses and longer RTs relative to single-task, baseline data. However, the demands on visual working memory were as high as those on verbal working memory, whereas demands on spatial working memory were minimal. The findings help to delineate the roles of the verbal, visual, and spatial working memory in written composition.
Policy Metamorphosis in China: A Case Study of Minban Education in Shanghai
Authors: Ding Xiaojiong
Published: September 2008

By taking minban education at the level of basic education in Shanghai as an example, this article studies the processes of policy implementation in mainland China. Based on 65 interviews conducted during 2001 and 2004, the article analyses two policies on minban education which have metamorphosed during implementation. It argues that the Chinese mode of state governance has shifted from Party despotism to a mode that tolerates and embraces local deviation.
Lunar Prospector observations of the electrostatic potential of the lunar surface and its response to incident currents
Authors: Halekas J. S. , Delory G. T. , Lin R. P. , Stubbs T. J. , Farrell W. M.
Published: September 2008

We present an analysis of Lunar Prospector Electron Reflectometer data from selected time periods using newly developed methods to correct for spacecraft potential and self‐consistently utilizing the entire measured electron distribution to remotely sense the lunar surface electrostatic potential with respect to the ambient plasma. These new techniques enable the first quantitative measurements of lunar surface potentials from orbit. Knowledge of the spacecraft potential also allows accurate characterization of the downward‐going electron fluxes that contribute to lunar surface charging, allowing us to determine how the lunar surface potential reacts to changing ambient plasma conditions. On the lunar night side, in shadow, we observe lunar surface potentials of ∼−100 V in the terrestrial magnetotail lobes and potentials of ∼−200 V to ∼−1 kV in the plasma sheet. In the lunar wake, we find potentials of ∼−200 V near the edges but smaller potentials in the central wake, where electron temperatures increase and secondary emission may reduce the magnitude of the negative surface potential. During solar energetic particle events, we see nightside lunar surface potentials as large as ∼−4 kV. On the other hand, on the lunar day side, in sunlight, we generally find potentials smaller than our measurement threshold of ∼20 V, except in the plasma sheet, where we still observe negative potentials of several hundred volts at times, even in sunlight. The presence of significant negative charging in sunlight at these times, given the measured incident electron currents, implies either photocurrents from lunar regolith in situ two orders of magnitude lower than those measured in the laboratory or nonmonotonic near‐surface potential variation with altitude. The functional dependence of the lunar surface potential on electron temperature in shadow implies somewhat smaller secondary emission yields from lunar regolith in situ than previously measured in the laboratory. These new techniques open the door for future studies of the variation of lunar surface charging as a function of temporal and spatial variations in input currents and as a function of location and material characteristics of the surface as well as comparisons to the increasingly sophisticated theoretical predictions now available.