bluuebunny/crossref_metadata_2025 huggingface dataset:
Prolonged acquired neutropenia in children
Authors: Sheen Jiunn‐Ming , Kuo Ho‐Chang , Yu Hong‐Ren , Huang Eng‐Yen , Wu Chih‐Chiang , Yang Kuender D.
Published: August 2009

Background

Acquired neutropenia is not uncommon in childhood. This study investigated the risk factors associated with developing prolonged acquired neutropenia.

Procedure

We reviewed 66,062 hospital admission medical records from the 5‐year period January 1, 2002 to December 31, 2006 to identify neutropenic patients, with and without follow‐up of their neutropenic course until December 31, 2007. After excluding patients with malignancy, collagen disease, bone marrow failure, prematurity, hereditary disease, congenital neutropenia, immunodeficiency, or status post‐liver transplantation, 735 admissions with acquired neutropenia were included in our study.

Results

A total of 474 patients with 735 admissions had moderate or severe neutropenia during the 5‐year period. Among the 252 acquired neutropenia patients who had follow‐up for at least 1 month, 226 patients recovered within 3 months, while 26 patients remained neutropenic after 3 months. Of these 26 patients, 14 recovered after 1 year. An absolute neutrophil count of <500/mm3 (odds ratio [OR]: 13.66, 95% confidence interval [CI]: 2.90–64.41), thrombocytosis (OR: 5.76, 95% CI: 1.78–18.58), and age <1 year (OR: 4.93, 95% CI: 1.03–23.54) were associated with prolonged acquired neutropenia, as shown by multivariate logistic regression. Kaplan–Meier analysis showed that neutropenia associated with cytomegalovirus (CMV) was more prolonged than neutropenia associated with influenza or Epstein–Barr virus infection.

Conclusions

Prolonged acquired neutropenia was associated with younger age, thrombocytosis, and CMV infection. Neutropenic infants with CMV infection may require antiviral therapy to prevent prolonged acquired neutropenia. Pediatr Blood Cancer 2009; 53:1284–1288. © 2009 Wiley‐Liss, Inc.
Life satisfaction of Swedish pediatric oncologists: The role of personality, work‐related aspects, and emotional distress
Authors: Stenmarker Margaretha , Palmérus Kerstin , Márky Ildikó
Published: August 2009

Background

The first nationwide, population‐based study of Swedish pediatric oncologists was conducted in 2006 and it revealed that various aspects of their life satisfaction obviously influenced their stress‐resilience. This second part of the study, with a response rate of 89% in the target group, therefore, focused on their life satisfaction and the role of personality, work‐related aspects, and emotional distress related to type of medical center and gender.

Procedure

This descriptive study was based on a cross‐sectional mail survey with questionnaires involving 90 pediatric oncologists. Using hierarchical regression models, their total, present, past, and future life satisfaction was analyzed.

Results

The vast majority (76.7%) stated that working in this medical field was very stimulating for their personal development. Male pediatricians were more satisfied with their present lives and physicians working at academic medical centers were more confident about the future. Some oncologists (13.4%), in particular females at non‐academic medical centers, needed professional help dealing with work‐related psychological problems. Personality trait (Hedonic Capacity) and low levels of depression contributed to every aspect of overall life satisfaction. Work‐related aspects influenced present and future life satisfaction. The models explained between 5% and 43% of the variance in life satisfaction in the whole group.

Conclusions

Pediatric oncologists face life‐threatening conditions and psychosocial issues factors that may negatively influence their life satisfaction. This study group, a single population of physicians, is characterized by an optimistic attitude and stable emotional status pointing to a high level of satisfaction, which is probably a main basic condition when meeting seriously ill children. Pediatr Blood Cancer 2009; 53:1308–1314. © 2009 Wiley‐Liss, Inc.
Impact of radiation attenuation and temperature evolution on monomer conversion of dimethacrylate‐based resins with a photobleaching photoinitiator
Authors: Mucci Veronica , Cook Wayne D. , Vallo Claudia
Published: August 2009

The photopolymerization process of a dimethacrylate copolymer system activated by the camphorquinone (CQ)/amine photoinitiator system (1 wt%), was experimentally studied under nonisothermal conditions in 1‐ and 2‐mm thick samples by measuring double bond conversion, temperature rise and radiation attenuation through the sample during polymerization. The peak temperature in 1‐ or 2‐mm thick samples irradiated at 5 mW/cm2 was 29 and 38°C, respectively. The temperature evolution during polymerization was also predicted by solving the energy balance coupled with the kinetic expressions for the reaction rate. Radiation attenuation as a function of depth by the photobleachable CQ results in spatial and temporal variation in the local rates of the kinetic steps involved. General relationships for spatiotemporal variations in concentration of a photobleaching initiator, in systems where attenuation and initiator consumption are taken into account, were used to compute local polymerization rates. The effects of radiation attenuation, photobleaching of the photoinitiator and variation of cure temperature at different depths into the resin, all compete to determine the double bond consumption. The increased radiation attenuation in the 2‐mm thick sample was accompanied by a higher cure temperature compared with the 1‐mm thick sample, and as a result, the monomer conversion averaged over the sample thickness in the 1‐ and 2‐mm thick samples was the same. Results obtained in this research highlight the inherent interlinking of thermal and radiation attenuation effects in bulk photopolymerizing systems. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
The influence of processing parameters on fingering formation in fluid‐assisted injection‐molded disks
Authors: Lin Kun‐Yeh , Liu Shih‐Jung
Published: August 2009

One of the problems encountered in fluid‐assisted injection‐molded parts is the gas or water “fingering” phenomenon, in which gas (water) bubbles penetrate nonuniformly into the core of the parts and form finger‐shape branches. Severe fingerings can lead to significant reductions in part stiffness. This study investigated the fingering phenomenon in fluid‐assisted injection‐molded disk parts. Experiments were carried out on a reciprocating injection‐molding machine equipped with gas‐ and water‐injection units. The material used was virgin polypropylene. A disk cavity with two different thicknesses was used for all experiments. The effects of various processing parameters on the fingering were examined. It was found that the melt short shot size and mold temperature were the principal parameters affecting the formation of part fingerings. In addition, the formation mechanism of part fingerings has also been proposed to better understand the formation of part fingerings. It has been shown that the fluid‐assisted filling process is an unstable system by nature. Any small perturbation by material viscosity or by temperature gradient can trigger the unbalance of gas (water) penetrations in the parts and result in fingerings. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Toughening effects of ethylene–vinyl acetate copolymers with different vinyl acetate content and viscosity on nylon 1010 blends
Authors: Yu Haiyang , Zhang Yong , Ren Wentan
Published: August 2009

Nylon 1010 blends with ethylene–vinyl acetate copolymer (EVA) and maleated ethylene–vinyl acetate (EVA‐g‐MAH) were prepared through melt blending. The vinyl acetate (VA) content and viscosity of EVA significantly affected the notched impact strength of nylon/EVA/EVA‐g‐MAH (80/15/5) blends. The nylon/EVA/EVA‐g‐MAH blends with high notched impact strength (over 60 kJ/m2) were obtained when the VA content in EVA ranged from 28 to 60 wt%. The effect of VA content on the notched impact strength of blends was related to the glass transition temperature for EVA with high VA content and crystallinity for EVA with low VA content. For nylon blends with EVA with the same VA content, low viscosity of EVA led to high notched impact strength. Fracture morphology of nylon/EVA/EVA‐g‐MAH (80/15/5) blends showed that blends with ductile fracture behavior usually had large matrix plastic deformation, which was the main energy dissipation mechanism. A relationship between the notched impact strength and the morphology of nylon/EVA/EVA‐g‐MAH (80/15/5) blends was well correlated by the interparticle distance model. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Structure, crystallization behavior, and thermal stability of PP/MCM‐41 nanocomposite
Authors: Wang Na , Fang Qinghong , Chen Erfan , Zhang Jing , Shao Yawei
Published: August 2009

The structure, crystallization, and thermal stability of polypropylene containing nanosized MCM‐41 particle, whose pore channels were filled with polystyrene inside the pore channels with the aid of supercritical CO2, were investigated by X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analyses, respectively. The results of differential scanning calorimetry showed that the incorporation of MCM‐41 (without template) increased the melting temperature and the crystallization temperature by approximately 7 and 1.8°C, respectively. Although the incorporation of MCM‐41 (with template) and MCM‐41‐S‐PS decreased the melting temperature, the crystallization temperature and the crystallization rate increased. The result of crystallization kinetics showed dramatic increase in crystallization rate and decrease in t1/2 and tf for PP/MCM‐41 (without template) nanocomposite, whereas decrease in crystallization rate and increase in t1/2 and tf for PP/MCM‐41 (with template) and PP/MCM‐41‐S‐PS nanocomposites. The thermal results indicated that the thermal stability of the composite was enhanced by addition of all nanoparticles. At the 95% weight loss, adding 2.5 wt% nanomaterial, the decomposition temperature of PP/MCM‐41‐S‐PS was 50.71°C higher than that of PP, 13.98°C higher than that of PP/MCM‐41 (without template), and 0.39°C higher than that of PP/MCM‐41 (with template). POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
A neck‐in model in extrusion lamination process
Authors: Shiromoto Seiji , Masutani Yasushi , Tsutsubuchi Masaaki , Togawa Yoshiaki , Kajiwara Toshihisa
Published: August 2009

In this study, the experiment of the extrusion lamination process using high‐pressure process low‐density polyethylene (LDPE) was performed. The nonisothermal viscoelastic simulation of the extrusion lamination experiment was also carried out. The simulation results were in good agreement with the experimental data within wide range of take up velocity and air gap length. We developed the theoretical model based on force balance and deformation type of a film to predict the neck‐in behavior in the extrusion lamination or cast film process. It was suggested from the neck‐in model that the neck‐in correlates with the ratio of planar to uniaxial elongational viscosity. It was confirmed that the neck‐in model could predict the film edge shape and neck‐in properly for conventional LDPE. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Flow pattern variations of viscoelastic fluid flows in three‐dimensional branching channel
Authors: Yamaguchi Hiroshi , Zhang Xin‐Rong , Matsumoto Tomoko
Published: August 2009

Transport phenomena in three‐dimensional branching channel are important because of their relevance in polymer processing. In this article, an experimental study on viscoelastic flow in a three‐dimensional cylindrical branching channel is carried out to investigate variations of flow pattern. Flow visualization in representative symmetric planes is made both for the viscoelastic fluid and Newtonian flow. From the results of the present investigation, the flow field in the three‐dimensional cylindrical branching channel is clarified within the range of laminar flow. It is confirmed that corner vortex, shedding vortex, and secondary vortex flow are all obviously changed with the fluid concentration and the Reynolds number, which are much more three‐dimensional and complex than the Newtonian fluid, and the flow pattern of the viscoelastic fliud flow largely depends on the Reynolds number and fluid concentration. Even for the viscoelastic flow at the low Reynolds number, shedding vortex and secondary vortex and complex three‐dimensional flow occur in the cylinder. The flow field is not symmetric space for the viscoelastic flow and however is fairly symmetric for the Newtonian fluid. The above reasons explain why the flow deflection happens even at the low Reynolds number flow. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Plasma Polymerization of HMDSO with an Atmospheric Pressure Plasma Jet for Corrosion Protection of Aluminum and Low‐Adhesion Surfaces
Authors: Lommatzsch Uwe , Ihde Jörg
Published: August 2009

Thin functional films were deposited on aluminum with an atmospheric pressure plasma jet using hexamethyldisiloxane (HMDSO) as precursor. A high dynamic deposition rate on the order of 450 nm · m · min−1 was achieved. Composition and structure of the thin films show a strong dependence on the downstream location of the precursor injection. A 4 mm downstream shift of the precursor injection increases the carbon content in the thin film by a factor of 2.5, as indicated by XPS analysis and alters the degree of cross‐linking according to the FTIR spectra. The coating with the low carbon content (17 at.‐%) provides corrosion resistance for aluminum 2024 unclad exposed for 96 h to a neutral salt spray test. The coating with the high carbon content reduces the adhesion of an epoxy resin to the surface and may be used as a release coating.

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A binding free energy decomposition approach for accurate calculations of the fidelity of DNA polymerases
Authors: Rucker Robert , Oelschlaeger Peter , Warshel Arieh
Published: August 2009

DNA polymerase β (pol β) is a small eukaryotic enzyme with the ability to repair short single‐stranded DNA gaps that has found use as a model system for larger replicative DNA polymerases. For all DNA polymerases, the factors determining their catalytic power and fidelity are the interactions between the bases of the base pair, amino acids near the active site, and the two magnesium ions. In this report, we study effects of all three aspects on human pol β transition state (TS) binding free energies by reproducing a consistent set of experimentally determined data for different structures. Our calculations comprise the combination of four different base pairs (incoming pyrimidine nucleotides incorporated opposite both matched and mismatched purines) with four different pol β structures (wild type and three mutants). We generate three fragments of the incoming deoxynucleoside 5′‐triphosphate‐TS and run separate calculations for the neutral base part and the highly charged triphosphate part, using different dielectric constants in order to account for the specific dielectric response. This new approach improves our ability to predict the effect of matched and mismatched base pairing and of mutations in DNA polymerases on fidelity and may be a useful tool in studying the potential of DNA polymerase mutations in the development of cancer. It also supports our point of view with regards to the origin of the structural control of fidelity, allowing for a quantified description of the fidelity of DNA polymerases. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Active and inactive state structures of unliganded Lactobacillus casei allosteric L‐lactate dehydrogenase
Authors: Arai Kazuhito , Ishimitsu Toshihiro , Fushinobu Shinya , Uchikoba Hiroyuki , Matsuzawa Hiroshi , Taguchi Hayao
Published: August 2009

Lactobacillus casei
L‐lactate dehydrogenase (LCLDH) is activated through the homotropic and heterotropic activation effects of pyruvate and fructose 1,6‐bisphosphate (FBP), respectively, and exhibits unusually high pH‐dependence in the allosteric effects of these ligands. The active (R) and inactive (T) state structures of unliganded LCLDH were determined at 2.5 and 2.6 Å resolution, respectively. In the catalytic site, the structural rearrangements are concerned mostly in switching of the orientation of Arg171 through the flexible intersubunit contact at the Q‐axis subunit interface. The distorted orientation of Arg171 in the T state is stabilized by a unique intra‐helix salt bridge between Arg171 and Glu178, which is in striking contrast to the multiple intersubunit salt bridges in Lactobacillus pentosus nonallosteric L‐lactate dehydrogenase. In the backbone structure, major structural rearrangements of LCLDH are focused in two mobile regions of the catalytic domain. The two regions form an intersubunit linkage through contact at the P‐axis subunit interface involving Arg185, replacement of which with Gln severely decreases the homotropic and hetertropic activation effects on the enzyme. These two regions form another intersubunit linkage in the Q‐axis related dimer through the rigid NAD‐binding domain, and thus constitute a pivotal frame of the intersubunit linkage for the allosteric motion, which is coupled with the concerted structural change of the four subunits in a tetramer, and of the binding sites for pyruvate and FBP. The unique intersubunit salt bridges, which are observed only in the R state structure, are likely involved in the pH‐dependent allosteric equilibrium. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Structure of the ribosome associating GTPase HflX
Authors: Wu Hao , Sun Lei , Blombach Fabian , Brouns Stan J.J. , Snijders Ambrosius P. L. , Lorenzen Kristina , van den Heuvel Robert H. H. , Heck Albert J. R. , Fu Sheng , Li Xuemei , Zhang Xuejun C. , Rao Zihe , van der Oost John
Published: August 2009

The HflX‐family is a widely distributed but poorly characterized family of translation factor‐related guanosine triphosphatases (GTPases) that interact with the large ribosomal subunit. This study describes the crystal structure of HflX from Sulfolobus solfataricus solved to 2.0‐Å resolution in apo‐ and GDP‐bound forms. The enzyme displays a two‐domain architecture with a novel “HflX domain” at the N‐terminus, and a classical G‐domain at the C‐terminus. The HflX domain is composed of a four‐stranded parallel β‐sheet flanked by two α‐helices on either side, and an anti‐parallel coiled coil of two long α‐helices that lead to the G‐domain. The cleft between the two domains accommodates the nucleotide binding site as well as the switch II region, which mediates interactions between the two domains. Conformational changes of the switch regions are therefore anticipated to reposition the HflX‐domain upon GTP‐binding. Slow GTPase activity has been confirmed, with an HflX domain deletion mutant exhibiting a 24‐fold enhanced turnover rate, suggesting a regulatory role for the HflX domain. The conserved positively charged surface patches of the HflX‐domain may mediate interaction with the large ribosomal subunit. The present study provides a structural basis to uncover the functional role of this GTPases family whose function is largely unknown. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Morphology of self‐assembled structures formed by short peptides from the amyloidogenic protein tau depends on the solvent in which the peptides are dissolved
Authors: Chaudhary Nitin , Singh Shashi , Nagaraj Ramakrishnan
Published: August 2009

The aggregation behavior of peptides Ac‐VQIVYK‐amide (AcPHF6) and Ac‐QIVYK‐amide (AcPHF5) from the amyloidogenic protein tau was examined by atomic force microscopy (AFM) and fluorescence microscopy. Although AcPHF5 did not show enhancement of thioflavin T (ThT) fluorescence in aqueous buffer, distinct aggregates were discernible when peptide was dissolved in organic solvents such as methanol (MeOH), trifluoroethanol (TFE), and hexafluoroisopropanol (HFIP) dried on mica and examined by AFM. Self‐association was evident even though the peptide did not have the propensity to form secondary structures in the organic solvents. In dried films, the peptide adopts predominantly β‐conformation which results in the formation of distinct aggregates. ThT fluorescence spectra and fluorescence images indicate the formation of fibrils when AcPHF6 solutions in organic solvents were diluted into buffer. AcPHF6 had the ability to organize into fibrillar structures when AFM samples were prepared from peptide dissolved in MeOH, TFE, HFIP, and also when diluted into buffer. AcPHF6 showed propensity for β‐structure in aqueous buffer. In MeOH and TFE, AcPHF6 showed helical and β‐structure. Morphology of the fibrils was dependent on peptide conformation in the organic solvents. The structures observed for AcPHF6 are formed rapidly and long incubation periods in the solvents are not necessary. The structures with varying morphologies observed for AcPHF5 and AcPHF6 appear to be mediated by surfaces such as mica and the organic solvents used for dissolution of the peptides. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
An improvement of quantum parametric methods by using SGSA parameterization technique and new elementary parametric functionals
Authors: Sánchez M. , Oldenhof M. , Freitez J. A. , Mundim K. C. , Ruette F.
Published: August 2009

A systematic improvement of parametric quantum methods (PQM) is performed by considering: (a) a new application of parameterization procedure to PQMs and (b) novel parametric functionals based on properties of elementary parametric functionals (EPF) [Ruette et al., Int J Quantum Chem 2008, 108, 1831]. Parameterization was carried out by using the simplified generalized simulated annealing (SGSA) method in the CATIVIC program. This code has been parallelized and comparison with MOPAC/2007 (PM6) and MINDO/SR was performed for a set of molecules with CC, CH, and HH bonds. Results showed better accuracy than MINDO/SR and MOPAC‐2007 for a selected trial set of molecules. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Magnetic interactions and electronic structure of uvarovite and andradite garnets. An ab initio all‐electron simulation with the CRYSTAL06 program
Authors: Meyer A. , Pascale F. , Zicovich‐Wilson C. M. , Dovesi R.
Published: August 2009

The ground‐state electronic structure of a number of magnetic phases of the garnets andradite (Ca3Fe2Si3O12) and uvarovite (Ca3Cr2Si3O12) has been investigated at the density functional theory level of approximation using the periodic ab initio code CRYSTAL. An all‐electron Gaussian‐type basis has been used in conjunction with the B3LYP hybrid functional. The exchange coupling constants between the first (J1a and J1b differentiating the two nonidentical sites), second (J2), and third (J3) nearest neighbors have been evaluated and are found to be in good agreement with the experimental data that is available for andradite. As a consequence of both the different J1a to J1b ratio and the opposite sign of J2 in the two minerals, different antiferromagnetic (AF) ground states are found for uvarovite and andradite, which is in agreement with experimental observation. Strong support for the additivity and transferability of the J constants is provided by calculations in which Cr and Fe ions are embedded in the related grossular structure. The mechanism for the stabilization of the AF states is discussed within the Anderson theory of superexchange; the kinetic energy gain in the AF states is calculated, and the spin density maps and profiles are examined. Density of states, charge density maps, and Mulliken population data complete the analysis of the electronic structure. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
How many‐body perturbation theory (MBPT) has changed quantum chemistry
Authors: Kutzelnigg Werner
Published: August 2009

The history of many‐body perturbation theory (MBPT) and its impact on Quantum Chemistry is reviewed, starting with Brueckner's conjecture of a linked‐cluster expansion and the time‐dependent derivation by Goldstone of such an expansion. A central part of this article is the time‐independent formulation of quantum chemistry in Fock space and its diagrammatic representation including the particle‐hole picture and the inversion of a commutator. The results of the time‐independent derivation of MBPT are compared with those of Goldstone. It is analyzed which ingredients of Goldstone's approach are decisive. The connected diagram theorem is derived both in a constructive way based on a Lie‐algebraic formulation and a nonconstructive way making use of the separation theorem. It is discussed why the Goldstone derivation starting from a unitary time‐evolution operator, ends up with a wave operator in intermediate normalization. The Møller–Plesset perturbation expansions of Bartlett and Pople are compared. Examples of complete summations of certain classes of diagrams are discussed, for example, that which leads to the Bethe‐Goldstone expansion. MBPT for energy differences is analyzed. The paper ends with recent developments and challenges, such as the generalization of normal ordering to arbitrary reference states, contracted Schrödinger k‐particle equations and Brillouin conditions, and finally the Nakatsuji theorem and the Nooijen conjecture. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Convergence radii of the polarization expansion of intermolecular potentials
Authors: Adams William H.
Published: August 2009

A new method is presented to evaluate convergence radii of the polarization expansion of interaction energies for pairs of atoms or molecules. The method is based on an analysis of the variation of the perturbed state vector as a function of the coupling constant λ and does not require a calculation of perturbation corrections to high order. The convergence radii at infinite interatomic/intermolecular distances R, as well as a remarkably accurate representation of the R dependence of the convergence radii are obtained from simple calculations involving only monomer wave functions. For the interaction of the lithium and hydrogen atoms, the obtained convergence radii agree well with those obtained previously from the large‐order calculations of Patkowski et al. (Patkowski et al., J Chem Phys, 2002, 117, 5124), but are expected to be considerably more accurate. Rigorous upper bounds and reasonable approximations to the convergence radii at R = ∞ are obtained for the pairs of lithium, beryllium, boron, neon, and sodium atoms, as well as for the dimer consisting of two LiH molecules. For all the systems studied, the convergence radii are significantly smaller than the unity and rapidly decrease with the increase of the nuclear charge. It is hoped that the results of this investigation will help to analyze and eventually to compute the convergence radii of the symmetry‐adapted perturbation theories which utilize the same partitioning of the Hamiltonian as the polarization expansion. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Mass spectrometry of intact neutral macromolecules using intense non‐resonant femtosecond laser vaporization with electrospray post‐ionization
Authors: Brady John J. , Judge Elizabeth J. , Levis Robert J.
Published: August 2009

Intact, nonvolatile, biological macromolecules can be transferred directly from the solid state into the gas phase, in ambient air, for subsequent mass spectral analysis using non‐resonant femtosecond (fs) laser desorption combined with electrospray ionization (ESI). Mass spectral measurements for neat samples, including a dipeptide, protoporphyrin IX and vitamin B12 adsorbed on a glass insulating surface, were obtained using an 800 nm, 70 fs laser with an intensity of 1013 W cm−2. No appreciable signal was detected when atmospheric matrix‐assisted or neat (matrix‐free) fs laser desorption was performed without ESI, indicating neutral desorption. Copyright © 2009 John Wiley & Sons, Ltd.
Determination of nivalenol and deoxynivalenol by liquid chromatography/atmospheric pressure photoionization mass spectrometry
Authors: Tanaka Hiroki , Takino Masahiko , Sugita‐Konishi Yoshiko , Tanaka Toshitsugu , Toriba Akira , Hayakawa Kazuichi
Published: August 2009

Fusarium species, a plant pathogenic fungus of wheat and other cereals, produces toxic metabolites such as nivalenol (NIV) and deoxynivalenol (DON). Control of contamination by these toxins is very difficult, and a continuous survey of the occurrence is necessary for these toxins. Thus, the accurate and convenient determination of the cereals contaminated with these toxins is important for the supply of safe foods. A selective analytical method based on high‐performance liquid chromatography, combined with atmospheric pressure photoionization (APPI) mass spectrometry, has been developed for simultaneous determination of NIV and DON. The parameters investigated for the optimization of APPI were the ion source parameters fragmentor voltage, capillary voltage, and vaporizer temperature, and also mobile phase composition and flow rate. Furthermore, chemical noise and signal suppression of analyte signals due to sample matrix interference were investigated for APPI. The results indicated that APPI provides lower matrix effect and the correlation coefficient of NIV and DON in the range 0.2–100 ng · mL−1 was above 0.999. Recoveries of NIV and DON in wheat ranged from 86 to 107% and limits of detection of NIV and DON were 0.20 ng · g−1 and 0.39 ng · g−1, respectively. In addition, the proposed method was applied for the analysis of naturally contaminated wheat samples. APPI was found to offer lower matrix effect and was a convenient technique for routine analysis of NIV and DON residues in wheat at trace levels. Copyright © 2009 John Wiley & Sons, Ltd.
Addressing agent loss in vehicle formations and sensor networks
Authors: Summers Tyler H. , Yu Changbin , Anderson Brian D. O.
Published: August 2009

In this paper, we address the problem of agent loss in vehicle formations and sensor networks via two separate approaches: (1) perform a ‘self‐repair’ operation in the event of agent loss to recover desirable information architecture properties or (2) introduce robustness into the information architecturea priorisuch that agent loss does not destroy desirable properties. We model the information architecture as a graphG(V, E), whereVis a set of vertices representing the agents andEis a set of edges representing information flow amongst the agents. We focus on two properties of the graph called rigidity and global rigidity, which are required for formation shape maintenance and sensor network self‐localization, respectively. For the self‐repair approach, we show that while previous results permit local repair involving only neighbours of the lost agent, the repair cannot always be implemented using only local information. We present new results that can be applied to make the local repair using only local information. We describe implementation and illustrate with algorithms and examples. For the robustness approach, we investigate the structure of graphs with the property that rigidity or global rigidity is preserved after removing any single vertex (we call the property as2‐vertex‐rigidityor2‐vertex‐global‐rigidity, respectively). Information architectures with such properties would allow formation shape maintenance or self‐localization to be performed even in the event of agent failure. We review a characterization of a class of2‐vertex‐rigidityand develop a separate class, making significant strides towards a complete characterization. We also present a characterization of a class of2‐vertex‐global‐rigidity. Copyright © 2008 John Wiley & Sons, Ltd.
The development of capabilities in new firms
Authors: Arikan Asli M. , McGahan Anita M.
Published: August 2009

This research explores evidence of corporate capabilities for conducting acquisition and alliance deals in young firms. We hypothesize that investors conjecture about the future based on information about a firm's capabilities. Each successive deal carries intrinsic value, creates experience, generates feedback, and yields information about the firm's underlying capabilities. We evaluate whether stock prices impute expectations that firms will capably pursue particular programs of acquisitions and alliances. The analysis covers how investor responses change across successive deals on the theory that firms with a concentrated program of deals may develop capabilities more intensively than those with programs that involve both acquisitions and alliances. The dataset covers the population of firms that went through an initial public offering (IPO) in the United States between 1988 and 1999. It contains information on all of their post‐IPO acquisitions and alliances, and on how their stock prices changed in response to the announcement of each deal. The results suggest that within the first year after IPO, investors expect firms to execute particular streams of alliances and acquisitions that reflect their unique histories of demonstrated capabilities. We also find evidence that investors cannot fully anticipate deal programs. The findings support a capabilities‐based view of the firm and also show that accurate inference using event‐study methods may require digging deep into the early histories of firms. Copyright © 2009 John Wiley & Sons, Ltd.
Alignment of Semiconductor Nanowires Using Ion Beams
Authors: Borschel Christian , Niepelt Raphael , Geburt Sebastian , Gutsche Christoph , Regolin Ingo , Prost Werner , Tegude Franz‐Josef , Stichtenoth Daniel , Schwen Daniel , Ronning Carsten
Published: August 2009

Gallium arsenide nanowires are grown on 〈100〉 GaAs substrates, adopting the epitaxial relation and thus growing with an angle around 35° off the substrate surface. These straight nanowires are irradiated with different kinds of energetic ions. Depending on the ion species and energy, downwards or upwards bending of the nanowires is observed to increase with ion fluence. In the case of upwards bending, the nanowires can be aligned towards the ion beam direction at high fluences. Defect formation (vacancies and interstitials) within the implantation cascade is identified as the key mechanism for bending. Monte Carlo simulations of the implantation are presented to substantiate the results.
Bioluminescent Imaging Demonstrates That Transplanted Human Embryonic Stem Cell-Derived CD34+ Cells Preferentially Develop into Endothelial Cells
Authors: Tian Xinghui , Hexum Melinda K. , Penchev Vesselin R. , Taylor Russell J. , Shultz Leonard D. , Kaufman Dan S.
Published: August 2009

Human embryonic stem cells (hESCs) provide an important resource for novel regenerative medicine therapies and have been used to derive diverse cell populations, including hematopoietic and endothelial cells. However, it remains a challenge to achieve significant engraftment of hESC-derived blood cells when transplanted into animal models. To better understand mechanisms that enhance or limit the in vivo developmental potential of hESC-derived cells, we utilized hESCs that express firefly luciferase (luc) to allow noninvasive, real-time bioluminescent imaging of hESC-derived CD34+ cells transplanted into the liver of neonatal immunodeficient mice. Serial imaging demonstrated stable engraftment and expansion of the luc+ hESC-derived cells in vivo over several months. While we found that these hESC-derived CD34+ cells have bipotential ability to generate both hematopoietic and endothelial lineages in vitro, these studies demonstrate preferential differentiation into endothelial cells in vivo, with only low levels of hematopoietic cell engraftment. Therefore, these studies reveal key differences in the developmental potential of hESC-derived cells using in vitro and in vivo analyses. Although transplanted hESC-derived CD34+ cells are well-suited for revascularization therapies, additional measures are needed to provide higher levels of long-term hematopoietic engraftment.

Disclosure of potential conflicts of interest is found at the end of this article.
Intramuscular Transplantation of G-CSF-Mobilized CD34+ Cells in Patients With Critical Limb Ischemia: A Phase I/IIa, Multicenter, Single-Blinded, Dose-Escalation Clinical Trial
Authors: Kawamoto Atsuhiko , Katayama Minako , Handa Nobuhiro , Kinoshita Makoto , Takano Haruna , Horii Miki , Sadamoto Kazuyo , Yokoyama Ayumi , Yamanaka Takeharu , Onodera Rie , Kuroda Akiko , Baba Rie , Kaneko Yuichiro , Tsukie Tomio , Kurimoto Yasuo , Okada Yukikatsu , Kihara Yasuki , Morioka Shigefumi , Fukushima Masanori , Asahara Takayuki
Published: August 2009

A number of preclinical studies have indicated the therapeutic potential of endothelial progenitor cells for vascular regeneration in ischemic diseases. A phase I/IIa clinical trial of transplantation of autologous CD34+ cells, the endothelial and hematopoietic progenitor-enriched fraction, was performed in no-option patients with atherosclerotic peripheral artery disease or Buerger's disease with critical limb ischemia (CLI). CD34+ cells were isolated from the G-CSF-mobilized apheresis product using a magnetic cell sorting system. CD34+ cells (105/kg, n = 6; 5 × 105/kg, n = 8; or 106/kg, n = 3) were injected i.m. into the leg with more severe ischemia. The Efficacy Score, representing changes in the toe brachial pressure index (TBPI), Wong-Baker FACES pain rating scale, and total walking distance 12 weeks after cell transplantation, the primary endpoint, was positive, indicating improvement in limb ischemia in all patients, although no significant dose-response relationship was observed. During the 12-week observation after cell therapy, the Wong-Baker FACES pain rating scale, TBPI, transcutaneous partial oxygen pressure, total or pain-free walking distance, and ulcer size serially improved in all patients. No death or major amputation occurred, and severe adverse events were rare, although mild to moderate events relating to G-CSF and leukapheresis were frequent during the 12-week follow-up. In conclusion, the outcomes of this prospective clinical study indicate the safety and feasibility of CD34+ cell therapy in patients with CLI. Favorable trends in efficacy parameters encourage a randomized and controlled trial in the future.

Disclosure of potential conflicts of interest is found at the end of this article.
Small-Molecule Induction of Neural Crest-like Cells Derived from Human Neural Progenitors
Authors: Hotta Ryo , Pepdjonovic Lana , Anderson Richard B. , Zhang Dongcheng , Bergner Annette J. , Leung Jessie , Pébay Alice , Young Heather M. , Newgreen Donald F. , Dottori Mirella
Published: August 2009

Neural crest (NC) cells are stem cells that are specified within the embryonic neuroectodermal epithelium and migrate to stereotyped peripheral sites for differentiation into many cell types. Several neurocristopathies involve a deficit of NC-derived cells, raising the possibility of stem cell therapy. In Hirschsprung's disease the distal bowel lacks an enteric nervous system caused by a failure of colonization by NC-derived cells. We have developed a robust method of producing migrating NC-like cells from human embryonic stem cell–derived neural progenitors using a coculture system of mouse embryonic fibroblasts. Significantly, subsequent exposure to Y27632, a small-molecule inhibitor of the Rho effectors ROCKI/II, dramatically increased the efficiency of differentiation into NC-like cells, identified by marker expression in vitro. NC-like cells derived by this method were able to migrate along NC pathways in avian embryos in ovo and within explants of murine bowel, and to differentiate into cells with neuronal and glial markers. This is the first study to report the use of a small molecule to induce cells with NC characteristics from embryonic stem cells that can migrate and generate neurons and support cells in complex tissue. Furthermore, this study demonstrates that small-molecule regulators of ROCKI/II signaling may be valuable tools for stem cell research aimed at treatment of neurocristopathies.

Disclosure of potential conflicts of interest is found at the end of this article.
System development planning using readiness levels in a cost of development minimization model
Authors: Magnaye Romulo B. , Sauser Brian J. , Ramirez‐Marquez Jose E.
Published: August 2009

The purpose of this paper is to describe a methodology that enables systems engineers or program managers to formulate a system‐wide optimal development plan in order to facilitate monitoring and evaluation of the development process in terms of the actual readiness of the system. It proposes the use of the System Readiness Level (SRL) scale to measure the maturity of a system composed of technological elements, which are being developed based on cost‐driven strategies (as opposed to time‐to‐market‐driven strategies). A constrained optimization model is used to identify which critical technology elements and integration links can be matured to which levels at a particular time such that the development costs are minimized while a targeted SRL value is attained on schedule. While the algorithm does not necessarily reduce the total cost of development, it is able to find the minimal amount of expenditures which will achieve the desired maturity level during the earlier part of the development process. Essentially, it shifts the rest of the expenditures towards the latter part of the development during which model‐based integration and testing procedures which have been suggested by others can be applied to reduce costs and time further. This can be a useful option to have when there is substantial uncertainty with the system due to its high novelty and technological content. As a value added approach, the model gives the systems engineer the information needed to understand what a delay may mean to development, so a more informed decision can be made. The paper concludes by discussing the possible use of the optimal development plan to monitor and control the progress of systems under development. © 2009 Wiley Periodicals, Inc. Syst Eng
PISA 2006: An assessment of scientific literacy
Authors: Bybee Rodger , McCrae Barry , Laurie Robert
Published: August 2009

This article introduces the essential features of the science component of 2006 Program for International Student Assessment (PISA). Administered every 3 years, PISA alternates emphasis on Reading, Mathematics, and Science Literacy. In 2006, PISA emphasized science. This article discusses PISA's definition of scientific literacy, the three competencies that constitute scientific literacy, the contexts used for assessment units and items, the role of scientific knowledge, and the importance placed on attitude toward science. PISA 2006 included a student test, a student questionnaire, and a questionnaire for school administrators. The student test employed a balanced incomplete block design involving thirteen 30‐minute clusters of items, including nine science clusters. The 13 clusters were arranged into thirteen 2‐hour booklets and each sampled student was assigned one booklet at random. Mean literacy scores are presented for all participating countries, and the percentages of OECD students at the six levels of proficiency are given for the combined scale and for the competency scales. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 865–883, 2009
Quantitative descriptions of resource choice in ecological models
Authors: Abrams Peter A.
Published: August 2009

This article reviews the subject of resource choice by consumers. It is concerned with how such choice has been and should be represented in quantitative ecological models. This requires consideration of the dynamics of behavioral change and the fitness consequences of different resource intake rates. The topic is important because of the impact of choice on the functional response of the consumer to each of the resources it consumes. A variety of open questions related to choice are addressed. These include: the relationship between optimal diet choice and switching; the relationship between adaptive choice of two or resources and type‐3 functional responses to a single resource; whether switching behavior requires choice and whether choice always results in switching behavior; why partial preferences are observed; whether choice between habitats is fundamentally different from choice within habitats; how between‐individual variation in parameters related to resource use alters functional responses measured at the population level. The impacts of choice on stability are discussed briefly. The costs of increased resource use and the type of nutritional interactions between resources are particularly important determinants of adaptive resource choice, and are considered in some detail.
Choline transporter gene variation is associated with attention-deficit hyperactivity disorder
Authors: English Brett A. , Hahn Maureen K. , Gizer Ian R. , Mazei-Robison Michelle , Steele Angela , Kurnik Daniel M. , Stein Mark A. , Waldman Irwin D. , Blakely Randy D.
Published: August 2009

The neurotransmitter acetylcholine (ACh) plays a critical role in brain circuits mediating motor control, attention, learning and memory. Cholinergic dysfunction is associated with multiple brain disorders including Alzheimer’s Disease, addiction, schizophrenia and Attention-Deficit Hyperactivity Disorder (ADHD). The presynaptic choline transporter (CHT, SLC5A7) is the major, rate-limiting determinant of ACh production in the brain and periphery and is consequently upregulated during tasks that require sustained attention. Given the contribution of central cholinergic circuits to the control of movement and attention, we hypothesized that functional CHT gene variants might impact risk for ADHD. We performed a case-control study, followed by family-based association tests on a separate cohort, of two purportedly functional CHT polymorphisms (coding variant Ile89Val (rs1013940) and a genomic SNP 3’ of the CHT gene (rs333229), affording both a replication sample and opportunities to reduce potential population stratification biases. Initial genotyping of pediatric ADHD subjects for two purportedly functional CHT alleles revealed a 2–3 fold elevation of the Val89 allele (n = 100; P = 0.02) relative to healthy controls, as well as a significant decrease of the 3’SNP minor allele in Caucasian male subjects (n = 60; P = 0.004). In family based association tests, we found significant overtransmission of the Val89 variant to children with a Combined subtype diagnosis (OR = 3.16; P = 0.01), with an increased Odds Ratio for a haplotype comprising both minor alleles. These studies show evidence of cholinergic deficits in ADHD, particularly for subjects with the Combined subtype, and, if replicated, may encourage further consideration of cholinergic agonist therapy in the disorder.
Measuring musculoskeletal pain by questionnaires: The manikin versus written questions
Authors: van den Hoven Linda H.J. , Gorter Kees J. , Picavet H. Susan J.
Published: August 2009

A picture of a human figure (manikin) on which pain can be indicated can be used to measure musculoskeletal pain in self administered or web‐based questionnaires. In this paper we present an analysis of the agreement between pain reported on a manikin and pain reported using written questions as assessed in the follow‐up questionnaire of the Dutch population‐based Musculoskeletal Conditions and Consequences Cohort (DMC3‐study). Both a manikin and extensive questions on pain were included and the agreement between the two measures was studied for nine pain locations. For a similar pain definition – pain lasting at least a week – the manikin gave slightly higher prevalences than the written questions. Around three quarter of those who reported pain on the written questionnaire also indicated pain on the manikin on the same anatomical location. There were no differences in the percentage of agreement by sex, age group or level of education, except for a lower percentage of agreement of the manikin among the elderly for pain in the lower extremities, neck and shoulder and among the lower level of education group for neck pain. Almost 6% of the participants reported pain according to the questions only and more than 10% (especially men) reported pain on the manikin only. We concluded that a manikin gives similar findings on prevalence of pain as written questions and could therefore be a good alternative for written questions only.