bluuebunny/crossref_metadata_2025 huggingface dataset:
Conventional and Propagation‐based Phase Contrast Imaging of Nanostructures Using Femtosecond Laser Driven Cluster Plasma Source and LiF Crystal Soft X‐ray Detectors
Authors: Gasilov S. , Faenov A. , Pikuz T. , Skobelev I. , Boldarev A. , Gasilov V. , Magunov A. , Fukuda Y. , Kando M. , Kotaki H. , Kawase K. , Kawachi T. , Daido H. , Tajima T. , Kato Y. , Bulanov S.
Published: October 2009

Bright source of soft X‐ray emission was developed. Soft X‐ray radiation was produced by femtosecond laser pulses irradiation of submicron size CO2 clusters. These clusters were produced in custom designed supersonic nozzle from the mixture of the 10% CO2 +90 % He expanding gases. Lithium fluorine based soft X‐ray detectors was used for registration of absorption images of ultrathin (nanoscale) foils and biological structures illuminated by the developed source. It was demonstrated that even ifthe foil is essentially transparent for the soft X‐ray radiation (like 100 nm thick Zr foil), the image contrast could be significantly increased due to the influence of propagation‐based phase‐contrast effect when detector is placed at the proper distance behind the sample (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Laser Excited Expanding Small Clusters: Single Time Distribution Functions
Authors: Raitza T. , Reinholz H. , Röpke G. , Morozov I. , Suraud E.
Published: October 2009

The time evolution of laser excited small clusters such as Na309 is investigated using a classical MD simulation code. Results for the electron phase space distribution are analyzed. We are interested intime dependent density and temperature profiles. The question of local thermal equilibrium is addressed comparing the simulated profiles with predictions from equilibrium statistical physics. Once the local thermal equilibrium is established, the time evolution of collective modes of the excited electron system can be investigated. For this, a restricted MD simulation scheme has been developed (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron Dynamics in Tight‐Binding Approximation ‐ the Influence of Thermal Anharmonic Lattice Excitations
Authors: Chetverikov A. P. , Ebeling W. , Velarde M.G.
Published: October 2009

We study here several basic problems of the quantum mechanics of electrons which are embedded into a onedimensional (1D) nonlinear, thermally excited lattice. Our approach uses the tight‐binding model for the dynamics of the electrons. Through coupling terms in the Hamiltonian the electron quantum dynamics is connected with the classical dynamics of the lattice endowed with Morse interactions. First it is shown that the electron forms bound states with the solitonic excitations in the lattice. These so‐called solectrons may move with supersonic speed. Then we study the effects of interference of solectrons with solitons. Finally we study the interference between thermal excitations on tunneling between two minima (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Energy Distribution of Electrons Expelled from Relativistically Intense Laser Beam
Authors: Galkin A.L. , Egorov V.A. , Kalashnikov M.P. , Korobkin V.V. , Romanovsky M.Yu. , Shiryaev O.B. , Trofimov V.A.
Published: October 2009

Motions of electrons driven by the fields of relativistically intense laser pulses are studied. The treatment is based on the numerical solution of the relativistic Newton's equation with the Lorentz force. It is demonstrated that an electron can be accelerated by a relativistically intense optical field up to a considerable part of the energy of its oscillation within the pulse. Energy spectra of the electrons scattered by an optical field are used to estimate the absolute value of the laser pulse intensity (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electric Field Fluctuations in the Systems of the Charged Particles with Exchange Interaction
Authors: Belyi V.V. , Kukharenko Yu.A.
Published: October 2009

The quantum plasma of Bose and Fermi particles is considered. A scheme of equation linearization for density matrix with the exchange interaction taken in account is proposed and the equation solution is found. An expression for Hartree‐ Fock dielectric permeatability with the exchange interaction is obtained. This interaction is taken into account in the exchange scattering amplitude. With the use of obtained solutions the non‐equilibrium spectral function of electric field fluctuations in presence of exchange interaction and medium polarization is found. It is shown that in the state of thermodynamic equilibrium a Fluctuation‐Dissipation Theorem holds. An expression for the system's response to an external electric field in presence of exchange interaction is given (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fast Electron Generation by Coulomb Scattering on Spatially Correlated Ions in a Strong Laser Field
Authors: Bauch S. , Bonitz M.
Published: October 2009

Electrons colliding with spatially fixed ions in strong laser fields are investigated by solving the time‐dependent Schrödinger equation. Considering first simple one‐dimensional model systems, the mechanisms and energy spectra of fast electrons are analyzed, starting from collisions on a single ion. By using these electrons as projectiles for a second and third collision, the maximum possible energy obtained can be significantly increased. We then generalize the analysis to 2D systems where additional angular degrees of freedom lead to a drastic loss of efficiency. This problem can be overcome by introducing external confinements, which allow to focus the electrons and increase the intensity of high‐energy electrons (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant Penetration of Intense Femtosecond Laser Pulses Through Plasma of Ultra‐Thin Foils
Authors: Bordyukh N.V. , Krainov V.P.
Published: October 2009

Simple analytic expression for the transmission coefficient as a function of foil thickness d describing penetration of intense femtosecond laser pulse through ultra‐thin foils with the thickness of the order of 100 nm has been derived using the Maxwell‐Vlasov‐Boltzmann equation. It is found that the transmission of laser radiation stops on the skin depth c/ωp, but sharp and narrow resonances take place at the foil thickness d > c/ωp where the there is no laser reflection (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generation of Zeptosecond Electromagnetic Pulses by Electrons Under their Interaction with Femtosecond Laser Pulses
Authors: Galkin A.L. , Korobkin V.V. , Romanovsky M.Yu. , Shiryaev O.B.
Published: October 2009

The motions of electrons driven by the fields of relativistically intense laser pulses are analyzed for the linear polarization. The treatment is based on the numerical solution of the relativistic Newton's equation with the Lorentz force for laser beams with Gaussian transverse intensity distribution. The electromagnetic radiation of an electron interacting with a laser pulse is also studied. It is shown that: laser fields accelerate electrons both in the transverse and longitudinal directions and the electron radiation comprises short pulses having zeptosecond (and even subzeptosecond) durations (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical Properties of the e–e+ Plasma Generated in the Focal Spot of a High‐Intensity Laser
Authors: Blaschke D. B. , Ilyine S. V. , Panferov A.D. , Röpke G. , Smolyansky S. A.
Published: October 2009

We discuss the high frequency conductivity and absorption coefficient of an quasiparticle electron ‐ positron plasma (EPP) created from the vacuum in a strong nonstationary electric field (nonstationary Schwinger mechanism), e.g., in the focus spot of two counterpropagating laser beams. The consideration is based on a strong nonperturbative approach. It is shown that the basic contribution here is due to vacuum polarization effects. For subcritical linearly polarised fields, we obtain the general expression for the induced conductivity and the absorption coefficient, which is investigated in a wide range of frequencies from the optical to the γ‐ray region. Some experimental consequences of the high absorptivity of the quasiparticle EPP are discussed (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ABCG2‐associated resistance to Hoechst 33342 and topotecan in a murine cell model with constitutive expression of side population characteristics
Authors: Smith Paul J. , Furon Emeline , Wiltshire Marie , Campbell Lee , Feeney Graham P. , Snyder Ronald D. , Errington Rachel J.
Published: October 2009

Drug resistant tumor “side‐populations,” enriched in cancer stem cells and identified by reduced accumulation of Hoechst 33342 under ABCG2‐mediated efflux, may compromise therapeutic outcome. Side‐population cells have predicted resistance to minor groove ligands, including the DNA topoisomerase I poison topotecan. We have used a stable Hoechst 33342‐resistant murine L cell system (HoeR415) to study resistance patterns, removing the need for SP isolation before microarray analysis of gene expression and the tracking of cell cycle dynamics and cytotoxicity. The majority of HoeR415 cells displayed a side‐population phenotype comparable with that of the side‐population resident in the ABCG2 over‐expressing A549 lung cancer cell line. Photo‐crosslinking showed direct protection against minor groove ligand residence on DNA, driven by ABCG2‐mediated efflux and not arising from any binding competition with endogenous polyamines. The covalent minor‐groove binding properties of the drug FCE24517 (tallimustine) prevented resistance suggesting a mechanism for overcoming SP‐related drug resistance. Hoechst 33342‐resistant murine cells showed lower but significant crossresistance to topotecan, again attributable to enhanced ABCG2 expression, enabling cells to evade S‐phase arrest. Hoechst 33342/TPT‐resistant cells showed limited ancillary gene expression changes that could modify cellular capacity to cope with chronic stress including over‐expression of Aldh1a1 and Mgst1, but under‐expression of Plk2 and Nnt. There was no evidence to link the putative stem cell marker ALDH1A1 with any augmentation of the TPT resistance phenotype. The study has implications for the patterns of drug resistance arising during tumor repopulation and the basal resistance to minor groove‐binding drugs of tumor side‐populations. © 2009 International Society for Advancement of Cytometry
Flow cytometry without alignment of collection optics
Authors: Sitton Greg , Srienc Friedrich
Published: October 2009

This study describes the performance of a new waveguide flow cell constructed from Teflon AF® (TFC) and the potential use of fiber optic splitters to replace collection objectives and dichroic mirrors. The TFC has the unique optical property that the refractive index of the polymer is lower than water and therefore, water filled TFC behaves and functions as a liquid core waveguide. Thus, as cells flow through the TFC and are illuminated by a laser orthogonal to the flow direction, scattered and fluorescent light is directed down the axis of the TFC to a fiber optic. The total signal in the fiber optic is then split into multiple fibers by fiber optic splitters to enable measurement of signal intensities at different wavelengths. Optical filters are placed at the terminus of each fiber before measurement of specific wavelengths by a PMT. The constructed system was used to measure DNA content of CHO and yeast cells. Polystyrene beads were used for alignment and to assess the performance of the system. Polystyrene beads were observed to produce light scattering signals with unique bimodal characteristics dependent on the direction of flow relative to the collecting fiber optic. © 2009 International Society for Advancement of Cytometry
Fundamentals of electrochemical detection techniques for CE and MCE
Authors: Kubáň Pavel , Hauser Peter C.
Published: October 2009

The electroanalytical techniques of amperometry, conductometry and potentiometry match well with the instrumental simplicity of CE. Indeed, all three detection approaches have been reported for electrophoretic separations. However, the characteristics of the three methods are quite distinct and these are not related to the optical methods more commonly employed. A detailed discussion of the underlying principles of each is given. The issue of possible effects of the separation voltage on the electrochemical detection techniques is considered in depth, and approaches to the elimination of such interferences are also discussed for each case.
Detection of hormone active chemicals using genetically engineered yeast cells and microfluidic devices with interdigitated array electrodes
Authors: Ino Kosuke , Kitagawa Yusuke , Watanabe Tsuyoshi , Shiku Hitoshi , Koide Masahiro , Itayama Tomoaki , Yasukawa Tomoyuki , Matsue Tomokazu
Published: October 2009

Endocrine disruptors that act like hormones in the endocrine system might have toxic effects. Therefore, it is important to develop a portable device that can detect hormone active chemicals in samples rapidly and easily. In this study, a microfluidic device was developed for the detection of hormone active chemicals using genetically engineered yeast cells. The yeast cells were used as biosensors since they were genetically engineered to respond to the presence of hormone active chemicals by synthesizing β‐galactosidase (β‐gal). For achieving further sensitivity, we incorporated interdigitated array (IDA) electrodes (width, 1.2 μm; gap, 0.8 μm) with 40 electrode fingers into the analytical chamber of the microfluidic device. The yeast cells precultured with a hormone active chemical, 17β‐estradiol (E2), were trapped from the main channel of the device to the analytical camber by electrophoresis. After trapping in the analytical chamber, we performed electrochemical detection of β‐gal induced in the yeast cells with the IDA electrodes. Actually, electrochemical detection was performed on p‐aminophenol that was converted from p‐aminophenyl‐β‐D‐galactopyranoside with β‐gal. The electrochemical signals from the yeast cells precultured with 17β‐estradiol were successfully detected with the device. Furthermore, the inhibitory effects of antagonists such as tamoxifen were also detected electrochemically by using the device. Thus, the present microfluidic device can be used for highly sensitive detection of hormone active chemicals.
Chemoselective ligand patterning of electroactive surfaces using microfluidics
Authors: Westcott Nathan P. , Yousaf Muhammad N.
Published: October 2009

To generate model substrates for cell adhesion, we have developed two different biocompatible strategies based on self‐assembled monolayers (SAMs) of alkanethiolates on gold terminated with latent ketones and aldehydes. Under spatial control, the hydroquinone and alcohol‐terminated SAMs can be oxidized to allow for oxyamine ligand patterning on the surface with microfluidic cassettes. These immobilization strategies were characterized by electrochemistry, fluorescence, and utilizing a cell adhesive peptide, cell patterns were generated.
Improving MCE with electrochemical detection using a bubble cell and sample stacking techniques
Authors: Guan Qian , Henry Charles S.
Published: October 2009

Two efforts to improve the sensitivity and limits of detection for MCE with electrochemical detection are presented here. One is the implementation of a capillary expansion (bubble cell) at the detection zone to increase the exposed working electrode surface area. Bubble cell widths were varied from 1× to 10× the separation channel width (50 μm) to investigate the effects of electrode surface area on detection sensitivity, LOD, and separation efficiency. Improved detection sensitivity and decreased detection limits were obtained with increased bubble cell width, and LODs of dopamine and catechol detected in a 5× bubble cell were 25 and 50 nM, respectively. Meanwhile, fluorescent imaging results demonstrated ∼8 and ∼12% loss in separation efficiency in 4× and 5× bubble cell, respectively. Another effort at reducing the LOD involves using field amplified sample injection for gated injection and field amplified sample stacking for hydrodynamic injection. Stacking effects are shown for both methods using amperometric detection and pulsed amperometric detection. The LODs of dopamine in a 4× bubble cell were 8 and 20 nM using field amplified sample injection and field amplified sample stacking, respectively. However, improved LODs were not obtained for anionic analytes using either stacking technique.
Prenatal sonographic diagnosis of short umbilical cord in a dichorionic twin with normal fetal anatomy
Authors: Sherer David M. , Dalloul Mudar , Ajayi Olusegun , Kheyman Mila , Sokolovski Margarita , Abulafia Ovadia
Published: October 2009

Short umbilical cords are associated with fetal anomalies, often including those with decreased or absent fetal movement, fetal akinesia/hypokinesia sequence, and restrictive dermopathies and aneuploidy. In normal fetuses, abnormally short umbilical cords have been associated with an increased risk of umbilical vessel hematomas, thrombosis, rupture, thrombocytopenia, cord compression, variable fetal heart rate decelerations, instrumental and operative deliveries, and fetal demise. We report a 24‐year‐old gravida 2, para 0 with a concordant dichorionic twin gestation, at 26 weeks' gestation, in whom sonography depicted fetuses with normal‐appearing anatomy as well as short umbilical cord of the 1st twin. Increased fetal surveillance was conducted. Following delivery at 36 weeks' gestation, the presence of a short umbilical cord of the 1st twin measuring 19 cm was confirmed. Systematic review of the literature confirms that this is the first report of prenatal diagnosis of a short umbilical cord in an otherwise normal fetus. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound 2010
Scrotal sonography revisited
Authors: Carkaci Selin , Ozkan Efe , Lane Deanna , Yang Wei T.
Published: October 2009

Sonography is the imaging modality of choice for the scrotum because it is simple, relatively inexpensive, and quick. Recent technological advances and transducer improvements have led to exquisite high‐resolution detail in gray‐scale as well as Doppler imaging. The purposes of this pictorial essay are to review the anatomy and embryology of the scrotal contents and to review the various scrotal and extrascrotal pathologic conditions, including acute scrotum, pediatric and adult testicular and extratesticular scrotal neoplasms, traumatic lesions, and miscellaneous other scrotal lesions. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound 2010
Subcutaneous lipoma compressing the common peroneal nerve and causing palsy: Sonographic diagnosis
Authors: Hsu Yi‐Chih , Shih Yen‐Yu I. , Gao Hong‐Wei , Huang Guo‐Shu
Published: October 2009

The compression of peripheral nerves by benign fatty tumors has rarely been reported in the literature. We present the case of a patient who had a subcutaneous lipoma in the region of the knee that caused common peroneal nerve palsy and appeared to compress the nerve on sonography. The surgical removal of subcutaneous lipoma allowed complete recovery. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound 2010
Mass spectrometry as a tool for characterization of N,N‐dialkylaminoethane‐ 2‐thiols—precursors and degradation products of chemical warfare agents
Authors: Papoušková Barbora , Bednář Petr , Stýskala Jakub , Hlaváč Jan , Barták Petr , Lemr Karel
Published: October 2009

N,N‐dialkylaminoethane‐2‐thiols belong to the group of precursors and degradation products of chemical warfare agents (CWAs). These compounds were analyzed by means of electrospray ionization‐multiple stage mass spectrometry (ion trap) and proposed fragments were confirmed by accurate mass measurement using a QqTOF system. The fragmentation pathways of studied compounds and the products of oxidation (formation of ‐S‐S‐ linkage) were described. Some minor interesting processes, such as rearrangement of SH group, were observed and proved. A new µLC/MS method, based on ion‐pairing chromatography, was developed. Trifluoroacetic acid was employed as an ion‐pairing agent to increase the low retention of compounds of interest in the reverse‐phase system. The technique was compared with the UPLC/MS method, allowing fast analysis of all the studied thiols as well as an explorative control of originated disulfides. Copyright © 2009 John Wiley & Sons, Ltd.
Ablation of articular cartilage with an erbium:YAG laser: An ex vivo study using porcine models under real conditions—ablation measurement and histological examination
Authors: Meister Jörg , Franzen René , Gavenis Karsten , Zaum Martin , Stanzel Sven , Gutknecht Norbert , Schmidt‐Rohlfing Bernhard
Published: October 2009

Background and Objectives

The use of an erbium:YAG laser in arthroscopic surgery has the advantage of a precise treatment of soft tissue. Due to the high absorption in water, the laser energy is perfectly matched to smoothing the hydrous, fibrillated articular cartilage surface. In minimal invasive surgery, the workspace is filled with aqueous liquids for enlargement. This appears contrary to the absorption characteristics of erbium:YAG laser radiation in water. The purpose of this study was to evaluate the ablated volume per pulse of cartilage lesions and the potential side effects including thermal damage and tissue necrosis.

Study Design/Materials and Methods

Twenty‐four osteochondral specimens of porcine knee joints were irradiated with an Er:YAG laser completely submerged in water, with distances to the cartilage surface of 1, 3 and 5 mm and pulse durations of 75 and 100 microseconds. To keep a constant peak power of approximately 6 kW, pulse energies of 450 and 580 mJ were used at a pulse repetition rate of 15 Hz. After a histological preparation, ablated volumes, depths, and widths of the cuts were investigated. Additionally, laser protocols were correlated with different markers of cartilage tissue damage and apoptosis.

Results

Ablation could be observed for every measurement. The influence of the distance showed a statistical significance (P < 0.001) for the volume, depth, and width of the cuts. For the pulse duration, statistical significance (P < 0.001) was found only for the volume and the depth. We observed no loss of proteoglycan or collagen type II. The total cell number, cell morphology, and number of apoptotic cells in an area close to the cutting edge and in a corresponding unaffected area of the same specimens revealed no differences regardless of the applied protocol.

Conclusion

The use of an Er:YAG laser demonstrates the successful application in liquid environments for cartilage removal without any damage of the surrounding tissue. Lasers Surg. Med. 41:674–685, 2009. © 2009 Wiley‐Liss, Inc.
Synthesis of Amorphous Hydrophobic Telechelic Hydrocarbon Diols via ADMET Polymerization
Authors: Schwendeman John E. , Wagener Kenneth B.
Published: October 2009

Amorphous, hydrophobic telechelic hydrocarbon diols were synthesized using acyclic diene metathesis (ADMET) polymerization. These diols can be used in hydrolysis and UV resistant polyurethanes. The hydrocarbon backbone is based on a mimic of an ethylene/isobutylene polymer, made by the ADMET polymerization of a gem‐dimethyl substituted α,ω‐diene followed by hydrogenation of the polymer's repeat unit unsaturation. Chain termination reactants (CTR's) having one, three, and nine methylene “spacers,” respectively, between their olefin and alcohol precursor group were used to cap the polymer chain ends to yield 2.0 functional telechelics. Use of the medium length CTR in a polymerization–depolymerization scheme, resulted in amorphous (Tg = −56 °C) telechelic diols with good molecular weight control.

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Synthesis of Supported Nickel Diimine Catalysts for Ethylene Slurry Polymerization
Authors: Choi Yiyoung , Soares João B. P.
Published: October 2009

Ethylene slurry polymerizations were performed using supported nickel diimine catalysts. The effects of catalyst structure and polymerization conditions on catalyst activity, polymer particle morphology, and polymer properties were investigated. Covalently attached supported nickel diimine catalysts activated with ethyl aluminum sesquichloride (EASC) have high activities and made polymers with spherical morphology. Compared with the equivalent homogeneous catalysts, the covalently attached supported catalysts produced polyethylene with higher melting temperatures, higher molecular weights, and broader molecular weight distributions. Borates used as internal activator during the synthesis of these supported catalysts successfully activated the nickel diimine complexes.

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“One‐pot” Synthesis of 1‐Vinyl‐2‐pyrrolidone with Protic Functional Groups in 3‐Position
Authors: Pérez Perrino Mónica , Navarro Rodrigo , Gómez Tardajos Myriam , Gallardo Alberto , Reinecke Helmut
Published: October 2009

A synthetic route that allows modification of 1‐vinyl‐2‐pyrrolidone with an alcohol or thiol group in its 3‐position in a one‐pot reaction without using protecting groups is described. The strategy used to achieve this goal is the reaction of the carboxamide anion of 1‐vinyl‐2‐pyrrolidone with cyclic precursors of these functionalities. It is furthermore shown that VP‐monomers functionalized with OH groups are suitable for the preparation of the corresponding copolymers with pure VP. As a second application of the new compounds, we also describe the synthesis of the first asymmetric crosslinker based on VP.

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A Molecular Dynamics Study of Two Apposing Polyelectrolyte Brushes with Mono‐ and Multivalent Counterions
Authors: Cao Qianqian , Zuo Chuncheng , He Hongwei , Li Lujuan
Published: October 2009

The conformational characteristics of polyelectrolytes end‐grafted on two apposing walls are studied. The monovalent and multivalent counterions are explicitly treated. It is found that the polyelectrolyte brushes undergo a collapse transition in the presence of multivalent counterions at large wall separations. Moreover, the brush thickness is linearly proportional to the grafting density and independent of the counterion valence. The effects of normal compression on the density profiles of monomers and counterions, the pressure, the net charge density and the degree of interpenetration are also studied. The density profiles of counterions exhibit an asymmetrical distribution in systems with a mixture of monovalent and trivalent counterions.

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Quantum‐Chemical Modeling of Free‐Radical Polymerization
Authors: Coote Michelle L.
Published: October 2009

This article reviews recent progress in the application of quantum chemistry to radical polymerization processes, with a principle focus on establishing the current ‘best‐practice’ methodology for obtaining chemically accurate calculations. The scope and limitations of computational chemistry for this field are also discussed, and some of its leading applications in the areas of ab initio kinetic modeling and computer‐aided reagent design are highlighted.

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FTIR Microscopy for Kinetic Measurements in High‐Throughput Photopolymerization: Experimental Design and Application
Authors: Johnson Peter M. , Stansbury Jeffrey W. , Bowman Christopher N.
Published: October 2009

Libraries with varying composition and exposure time were developed to enable high‐throughput analysis of conversion using FTIR spectroscopy. This technique was demonstrated by measuring viscosity and backbone chain structure effects using four monomers: DPGDA, TEGDA, bisphenol‐A‐glycidyl diacrylate and ethoxylated bisphenol‐A diacrylate. DPGDA has equivalent viscosity and double bond concentration with a shorter backbone chain length as compared to TEGDA. The ultimate conversion of TEGDA copolymerizations as compared to equivalent DPGDA copolymerizations is lowered from 15 to 5% due to differences in crosslink space chemistry and glass transition temperatures of the copolymer formulation.

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Prospective study of peripheral neuropathy in Machado–Joseph disease
Authors: C. França Marcondes , D'abreu Anelyssa , Nucci Anamarli , Cendes Fernando , Lopes‐Cendes Iscia
Published: October 2009

Peripheral neuropathy (PN) has long been recognized in Machado–Joseph disease (MJD), but its natural history is an unsettled issue. Therefore, we prospectively assessed 40 with MJD for 13 months with nerve conduction (NC) studies and the revised total neuropathy score (TNSr) to study the progression of PN. There was no significant change in the TNSr score over the follow‐up period. In contrast, the average sural sensory nerve action potential (SNAP) amplitude decreased significantly over the same interval from a mean of 13.2 μV to 9.8 μV (P < 0.001). There was an inverse correlation between the change in the sural SNAP amplitude and the length of the CAG triplet repeat expansion (r = 0.574, P < 0.001). The reduction in the mean sural SNAP amplitude also correlated with progression of ataxia. This indicates that PN progresses faster in individuals with larger (CAG)n expansions, and nerve conduction studies may be useful to study disease progression in MJD. Muscle Nerve, 2009
Effect of locally delivered IGF‐1 on nerve regeneration during aging: An experimental study in rats
Authors: Apel Peter J. , Ma Jianjun , Callahan Michael , Northam Casey N. , Alton Timothy B. , Sonntag William E. , Li Zhongyu
Published: October 2009

Age is an important predictor of neuromuscular recovery after peripheral nerve injury. Insulin‐like growth factor 1 (IGF‐1) is a potent neurotrophic factor that is known to decline with increasing age. The purpose of this study was to determine if locally delivered IGF‐1 would improve nerve regeneration and neuromuscular recovery in aged animals. Young and aged rats underwent nerve transection and repair with either saline or IGF‐1 continuously delivered to the site of the nerve repair. After 3 months, nerve regeneration and neuromuscular junction morphology were assessed. In both young and aged animals, IGF‐1 significantly improved axon number, diameter, and density. IGF‐1 also significantly increased myelination and Schwann cell activity and preserved the morphology of the postsynaptic neuromuscular junction (NMJ). These results show that aged regenerating nerve is sensitive to IGF‐1 treatment. Muscle Nerve, 2009
Algorithmic and analytical methods in network biology
Authors: Koyutürk Mehmet
Published: October 2009

During the genomic revolution, algorithmic and analytical methods for organizing, integrating, analyzing, and querying biological sequence data proved invaluable. Today, increasing availability of high‐throughput data pertaining to functional states of biomolecules, as well as their interactions, enables genome‐scale studies of the cell from a systems perspective. The past decade witnessed significant efforts on the development of computational infrastructure for large‐scale modeling and analysis of biological systems, commonly using network models. Such efforts lead to novel insights into the complexity of living systems, through development of sophisticated abstractions, algorithms, and analytical techniques that address a broad range of problems, including the following: (1) inference and reconstruction of complex cellular networks; (2) identification of common and coherent patterns in cellular networks, with a view to understanding the organizing principles and building blocks of cellular signaling, regulation, and metabolism; and (3) characterization of cellular mechanisms that underlie the differences between living systems, in terms of evolutionary diversity, development and differentiation, and complex phenotypes, including human disease. These problems pose significant algorithmic and analytical challenges because of the inherent complexity of the systems being studied; limitations of data in terms of availability, scope, and scale; intractability of resulting computational problems; and limitations of reference models for reliable statistical inference. This article provides a broad overview of existing algorithmic and analytical approaches to these problems, highlights key biological insights provided by these approaches, and outlines emerging opportunities and challenges in computational systems biology. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Analytical and Computational Methods > Analytical Methods
Modeling actin dynamics
Authors: Bindschadler Mike
Published: October 2009

Actin monomers assemble into filaments that structurally support cells as well as drive membrane protrusion for cell movement. Within cells, some actin structures are very dynamic and turn over rapidly, while others are very stable. Even purified actin filament dynamics are complex, and researchers have often turned to mathematical models in order to interpret data, test hypotheses, make predictions, and deepen understanding. Models of actin dynamics can be broadly divided into time‐dependent models and time‐independent models. Most commonly, time‐independent models use numerical solutions of sets of differential equations to explore the effects of key parameters on the actin cycle at steady state. Recent examples have been used to predict the nucleotide profile of steady‐state filaments and to illuminate the mechanisms behind profilin's effects on actin dynamics. Time‐dependent models of actin dynamics have been either Monte Carlo simulations, which track individual filaments at various levels of detail or less commonly stochastic models, which have been explored and solved analytically. These Monte Carlo and stochastic models have recently been used to investigate filament length diffusion, filament length distributions, annealing and fragmentation, and pyrene fluorescence overshoots. We do not review force production/protrusion models as they tend to reduce the complexity of actin dynamics to a single 'elongation rate' and because these models have been recently well reviewed.1. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Models of Systems Properties and Processes > Cellular Models
Effect of age and physical activity level on functional fitness in older adults
Authors: Donat Tuna Hulya , Ozcan Edeer Ayse , Malkoc Mehtap , Aksakoglu Gazanfer
Published: October 2009

It is difficult to distinguish between the effects of age and physical activity level in the functional fitness level of older adults. The objective of this study was to determine the effects of age and physical activity level on some functional fitness parameters in community-dwelling older adults.Two hundred twenty-nine elderly (111 female; 118 male) aged between 65–87 years living in the Balçova municipality region were divided into two groups: the young elderly (65–69 years old) and the elderly (70 years old or over). The “seven-day physical activity recall questionnaire” was used to estimate physical activity level (PAL). The functional fitness evaluation included the body mass index (BMI), the lower body strength (LBS), the dynamic balance, and the aerobic endurance. The young elderly were significantly worse with regard to BMI and significantly better with regard to LBS, dynamic balance, and aerobic endurance than the elderly; in contrast, PAL did not affect any of the functional fitness parameters. The young elderly showed worse BMI than the elderly when the age groups were less active. The young elderly showed better LBS and dynamic balance than the elderly when the age groups were more active. The young elderly showed significantly better aerobic endurance than the elderly in both the less and more active age groups. This study confirms that age affects functional fitness, whereas PAL generally does not. However, being more active is advantageous for the young elderly with regard to BMI, LBS, and dynamic balance.
Antioxidant Activity of the Phenolic Leaf Extracts from Monechma ciliatum in Stabilization of Corn Oil
Authors: Mariod Abdalbasit Adam , Ibrahim Ramlah Mohamad , Ismail Maznah , Ismail Norsharina
Published: October 2009

The total phenolic content and the antioxidant potential of methanolic extract (ME), ethyl acetate extract (EAE), and hexane extract (HE) from Monechma ciliatum leaves (MCL) were evaluated. The Folin‐Ciocalteu, β‐carotene bleaching, the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging and the accelerated oxidation methods were used for evaluation. Both the extraction yield and the antioxidant activity (AOA) were strongly dependent on the solvent. Among the extracts, ME exhibited highest total phenolic compounds (TPC) and IC50 values for DPPH, followed by EAE and HE, respectively. Peroxide value (PV), anisidine value (AV) conjugated dienes (CD), and thiobarbituric acid reactive substances (TBARS) were taken as the parameters for evaluation of stabilization efficacy of MCL extracts and results revealed MCL to be a potent antioxidant for the stabilization of corn oil. As a general trend, increased AOA was observed for increased extract concentration. The predominant phenolic compounds identified by HPLC‐DAD in MCL extracts were p‐coumaric acid, vanillin and ferulic acid.
Connexin‐mediated communication controls cell proliferation and is essential in retinal histogenesis
Authors: Kihara Alexandre H. , Santos Taisa O. , Osuna‐Melo Edgard J. , Paschon Vera , Vidal Kallene S.M. , Akamine Priscilla S. , Castro Leandro M. , Resende Rodrigo R. , Hamassaki Dânia E. , Britto Luiz R.G.
Published: October 2009

Connexin (Cx) channels and hemichannels are involved in essential processes during nervous system development such as apoptosis, propagation of spontaneous activity and interkinetic nuclear movement. In the first part of this study, we extensively characterized Cx gene and protein expression during retinal histogenesis. We observed distinct spatio‐temporal patterns among studied Cx and an overriding, ubiquitous presence of Cx45 in progenitor cells. The role of Cx‐mediated communication was assessed by using broad‐spectrum (carbenoxolone, CBX) and Cx36/Cx50 channel‐specific (quinine) blockers. In vivo application of CBX, but not quinine, caused remarkable reduction in retinal thickness, suggesting changes in cell proliferation/apoptosis ratio. Indeed, we observed a decreased number of mitotic cells in CBX‐injected retinas, with no significant changes in the expression of PCNA, a marker for cells in proliferative state. Taken together, our results pointed a pivotal role of Cx45 in the developing retina. Moreover, this study revealed that Cx‐mediated communication is essential in retinal histogenesis, particularly in the control of cell proliferation.
The habitual consumer
Authors: Wood Wendy , Neal David T.
Published: October 2009

Consumers sometimes act like creatures of habit, automatically repeating past behavior with little regard to current goals and valued outcomes. To explain this phenomenon, we show that habits are a specific form of automaticity in which responses are directly cued by the contexts (e.g., locations, preceding actions) that consistently covaried with past performance. Habits are prepotent responses that are quick to activate in memory over alternatives and that have a slow‐to‐modify memory trace. In daily life, the tendency to act on habits is compounded by everyday demands, including time pressures, distraction, and self‐control depletion. However, habits are not immune to deliberative processes. Habits are learned largely as people pursue goals in daily life, and habits are broken through the strategic deployment of effortful self‐control. Also, habits influence the post hoc inferences that people make about their behavior.
Sporttherapiein der Behandlung somatoformer Beschwerden
Authors: Schwarz Daniela , Gießing Jürgen , Heider Jens , Zaby Alexandra , Schröder Annette
Published: October 2009

Zusammenfassung. Ziel der vorliegenden Arbeit ist es, einen Überblick über den bisherigen empirischen Forschungsstand zur Wirksamkeit der Sporttherapie bei somatoformen Beschwerden zu geben. Auf Grund des defizitären Forschungsstandes bei somatoformen Beschwerden im engeren Sinne werden auch Studien zur Sporttherapie bei Fibromyalgie, dem chronischen Müdigkeitssyndrom und dem Reizdarmsyndrom berücksichtigt. Für die Fibromyalgie und das chronische Müdigkeitssyndrom ist die Wirksamkeit von Sporttherapie als evidenzbasiert anzusehen. Gute Evidenzen liegen für ein sporttherapeutisches Angebot vor, welches entweder ein Ausdauer- oder ein Kombinationstraining (Ausdauer und Stretching/Krafttraining) beinhaltet. Für somatoforme Beschwerden im engeren Sinne ist der Forschungsstand zum gegenwärtigen Zeitpunkt zu gering, um eine abschließende Aussage treffen zu können. Implikationen für weiteren Forschungsbedarf werden dargelegt.
Essstörungen und Leistungssport
Authors: Schneider Nora , Bayios Verena , Pfeiffer Ernst , Lehmkuhl Ulrike , Salbach-Andrae Harriet
Published: October 2009

Zusammenfassung. Aufgrund der starken Schlankheitsorientierung in ästhetischen Sportarten und kontroverser Befunde zur Rolle von Leistungssport für die Genese von Essstörungen gingen wir in vorliegender Untersuchung der Frage nach essstörungsspezifischer Psychopathologie unter besonderer Berücksichtigung des Körperbildes bei Sportlerinnen verschiedener ästhetischer Sportarten nach. 65 Leistungssportlerinnen aus der Rhythmischen Sportgymnastik (RSG) und dem Eiskunstlauf (EKL) wurden im Vergleich zu Patientinnen mit Anorexia nervosa (AN) und einer gesunden Kontrollgruppe (KG) untersucht. Unsere Ergebnisse zeigen keine Unterschiede zwischen den RSG und der KG, hingegen deutliche Unterschiede zu den AN-Patientinnen. RSG und EKL unterschieden sich lediglich in der Einschätzung des Oberschenkelumfangs, wobei letztere sich stärker überschätzten. Für die EKL fanden wir Ähnlichkeiten zu den AN-Patientinnen in der Überschätzung des Umfangs ihres eigenen Oberschenkels, Perfektionismus und Misstrauen gegenüber anderen. Unsere Ergebnisse weisen auf leichte Unterschiede zwischen den untersuchten Sportarten hin und betonen somit die Notwendigkeit einer differenzierten Betrachtung unterschiedlicher ästhetischer Sportarten in Bezug auf die Diskussion um körperbetonte Sportarten und Essstörungen/essstörungsrelevante Psychopathologie.
Unterschiede im physischen Selbstkonzept bei normalgewichtigen und adipösen Personen
Authors: Jüntgen Liv , Freund Alexander , Tietjens Maike , Holling Heinz
Published: October 2009

Zusammenfassung. Der vorliegende Beitrag befasst sich mit Besonderheiten des physischen Selbstkonzepts von Personen mit Adipositas. Theoretische Grundlage bildet dabei das Modell zum Selbstkonzept von Shavelson, Hubner und Stanton, (1976) , das für Modelle zum physischen Selbstkonzept übernommen und weiterentwickelt wurde. Der auf Basis dieser Modelle entwickelte Physical Self Description Questionnaire (PSDQ; Marsh, Richards, Johnson, Roche & Tremayne, 1994 ) wird dabei als Messinstrument verwendet. Im ersten Teil der Studie werden zum einen Besonderheiten des physischen Selbstkonzepts adipöser Personen verglichen mit normalgewichtigen Kontrollprobanden und zum anderen wird die Bedeutung sportlicher Aktivität für das Selbstkonzept adipöser Personen untersucht. Der zweite Teil der Studie beschäftigt sich mit der Erklärung des globalen physischen Selbstwerts durch verschiedene Komponenten des physischen Selbstkonzepts bei adipösen und normalgewichtigen Probanden. Die Ergebnisse deuten daraufhin, dass sich das physische Selbstkonzept adipöser Personen in verschiedener Hinsicht von dem Normalgewichtiger unterscheidet. Abschließend erfolgt die Ableitung von Implikationen, die sich aus diesen Ergebnissen für Forschung und Praxis ergeben.
„Sport macht mich high”
Authors: Kaya Roessler Kirsten
Published: October 2009

Zusammenfassung. Die Bedeutung körperlicher Bewegung bei der Behandlung von Drogenmissbrauch wird anhand eines Interventionsprojekts diskutiert. Hierbei liegt besondere Aufmerksamkeit auf der Veränderung des Verhaltens, der Körperwahrnehmung und des Selbstvertrauens der Teilnehmer. Patienten einer dänischen Tagesklinik nahmen mindestens zwei Monate drei Mal wöchentlich an einem physischen Training teil. Interviewdaten wurden zu Beginn, am Ende und ein Jahr nach der Intervention erhoben und beinhalteten Informationen zur Art und zum Umfang des Missbrauchs, zum Körpergefühl und zur Motivation für eine Verhaltensänderung. Die Resultate dokumentieren neben einer erhöhten körperlichen Fitness ein verbessertes Körpergefühl, eine erhöhte Schmerzempfindlichkeit und eine reduzierte Drogeneinnahme. Die Langzeituntersuchung nach einem Jahr zeigt, dass körperliche Aktivität die sozialen Fähigkeiten und die subjektiv erlebte Körper- und Verhaltenskontrolle stärkt. Es zeigt sich aber auch, dass ein anhaltender Effekt dieser Veränderungen stark von einer positiven sozialen Umgebung abhängig ist.
Activation and Persistence of Implicit Causality Information in Spoken Language Comprehension
Authors: Pyykkönen Pirita , Järvikivi Juhani
Published: October 2009

A visual world eye-tracking study investigated the activation and persistence of implicit causality information in spoken language comprehension. We showed that people infer the implicit causality of verbs as soon as they encounter such verbs in discourse, as is predicted by proponents of the immediate focusing account ( Greene & McKoon, 1995 ; Koornneef & Van Berkum, 2006 ; Van Berkum, Koornneef, Otten, & Nieuwland, 2007 ). Interestingly, we observed activation of implicit causality information even before people encountered the causal conjunction. However, while implicit causality information was persistent as the discourse unfolded, it did not have a privileged role as a focusing cue immediately at the ambiguous pronoun when people were resolving its antecedent. Instead, our study indicated that implicit causality does not affect all referents to the same extent, rather it interacts with other cues in the discourse, especially when one of the referents is already prominently in focus.
Dynamic Visual Noise Affects Visual Short-Term Memory for Surface Color, but not Spatial Location
Authors: Dent Kevin
Published: October 2009

In two experiments participants retained a single color or a set of four spatial locations in memory. During a 5 s retention interval participants viewed either flickering dynamic visual noise or a static matrix pattern. In Experiment 1 memory was assessed using a recognition procedure, in which participants indicated if a particular test stimulus matched the memorized stimulus or not. In Experiment 2 participants attempted to either reproduce the locations or they picked the color from a whole range of possibilities. Both experiments revealed effects of dynamic visual noise (DVN) on memory for colors but not for locations. The implications of the results for theories of working memory and the methodological prospects for DVN as an experimental tool are discussed.
When Arnold is “The Terminator”, We No Longer See Him as a Man
Authors: Quinn Kimberly A. , Mason Malia F. , Macrae C. Neil
Published: October 2009

The current research examined the intersection of social categorization and identity recognition to investigate whether and when one form of construal would dominate people’s responses to social targets. Using an automatic priming paradigm and manipulating prime duration to examine how familiarity with social targets and the time course of processing moderate construal, we asked participants to judge the familiarity and sex of faces (Experiments 1 and 2, respectively). The results revealed that both unfamiliar and familiar faces were initially categorized by sex but that familiar faces were quickly (and automatically) reclassified in terms of identity. Implications for models of face processing and person perception are discussed.
Affect 4.0
Authors: Spruyt Adriaan , Clarysse Jeroen , Vansteenwegen Debora , Baeyens Frank , Hermans Dirk
Published: October 2009

We describe Affect 4.0, a user-friendly software package for implementing psychological and psychophysiological experiments. Affect 4.0 can be used to present visual, acoustic, and/or tactile stimuli in highly complex (i.e., semirandomized and response-contingent) sequences. Affect 4.0 is capable of registering response latencies and analog behavioral input with millisecond accuracy. Affect 4.0 is available free of charge.