bluuebunny/crossref_metadata_2025 huggingface dataset:
Antiparallel magnetic reconnection rates at the Earth's magnetopause
Authors: Fuselier S. A. , Petrinec S. M. , Trattner K. J.
Published: October 2010

Cluster observations at the Earth's high‐latitude magnetopause are combined with magnetic field models to demonstrate that antiparallel reconnection was occurring at the magnetopause for an event on 3 December 2001. Over a 20 min period, the reconnection line passed over the spacecraft on two occasions. In between the encounters with the reconnection line, velocity cutoffs in the ion distributions are used to determine the distance to the reconnection site. These observations are consistent with an antiparallel reconnection line whose location relative to the spacecraft depends on the orientation of the interplanetary magnetic field. Using this knowledge of the reconnection site location and a previously developed, two‐spacecraft method for computing the inflow velocity into the reconnection site, the reconnection rate (Vn/VA) is determined to be ∼0.08. The rate is consistent with fast reconnection and considerably higher than the reconnection rate for a component reconnection event that was determined using the same two‐spacecraft method.
Drift shell bifurcation near the dayside magnetopause in realistic magnetospheric magnetic fields
Authors: Wan Yifei , Sazykin Stanislav , Wolf Richard A. , Öztürk M. Kaan
Published: October 2010

We study trapped energetic particles in the terrestrial magnetosphere undergoing drift shell bifurcation in the magnetic field lacking north‐south and east‐west symmetry. Drift shell bifurcation occurs near the dayside magnetopause, where, due to the solar wind compression, the field strength has a local maximum near the equatorial plane. As a result, a charged particle may become temporarily trapped in one of the hemispheres while traversing the region. Although this phenomenon has been known for a long time, only recently were the associated second invariant changes quantified for the magnetic field with north‐south and east‐west symmetry. Here we show that if the magnetic field lacks such symmetry, the effect is more significant. We calculate changes to the second invariant of keV to MeV electrons in Tsyganenko magnetic fields with nonzero interplanetary magnetic field (IMF) BY component. The changes are on the order of the invariant itself, and thus, this effect is much larger than for the case of symmetric magnetic field (when the particle gyroradius is much less than the magnetospheric scale length). We also quantify the effect for different values of the solar wind dynamic pressure, IMF BZ component, and the Dst index with the Tsyganenko magnetic field T02. We find that Dst has no noticeable role, while larger solar wind ram pressure increases the second invariant changes. We verify our calculations by numerical integration of the guiding center drift equations and discuss properties of different versions of these equations.
Influence of cusp O+ outflow on magnetotail dynamics in a multifluid MHD model of the magnetosphere
Authors: Wiltberger M. , Lotko W. , Lyon J. G. , Damiano P. , Merkin V.
Published: October 2010

A multifluid version of the Lyon‐Fedder‐Mobarry global simulation model has been used to investigate the effects of outflowing ionospheric O+ on the magnetosphere‐ionosphere system. To quantify these effects, we specify the number density, upward parallel velocity, and temperature of the O+ outflow in a limited area of the low‐altitude simulation boundary representing the projection of cusp, cleft, and low‐latitude boundary layer. A baseline simulation without O+ outflow is compared with simulations with a range of fluxes and initial velocities. In the cases with high fluxes, it is shown that the configuration of the magnetosphere is dramatically changed. In particular, the cross‐polar cap potential is reduced, the polar cap area is increased, and the nightside reconnection line is moved earthward. Furthermore, in one case, the O+ outflow leads to the onset of a second substorm not seen in the other simulation runs.
The protein phosphatase 1 regulator PNUTS is a new component of the DNA damage response
Authors: Landsverk Helga B , Mora‐Bermúdez Felipe , Landsverk Ole J B , Hasvold Grete , Naderi Soheil , Bakke Oddmund , Ellenberg Jan , Collas Philippe , Syljuåsen Randi G , Küntziger Thomas
Published: October 2010

The function of protein phosphatase 1 nuclear‐targeting subunit (PNUTS)—one of the most abundant nuclear‐targeting subunits of protein phosphatase 1 (PP1c)—remains largely uncharacterized. We show that PNUTS depletion by small interfering RNA activates a G2 checkpoint in unperturbed cells and prolongs G2 checkpoint and Chk1 activation after ionizing‐radiation‐induced DNA damage. Overexpression of PNUTS–enhanced green fluorescent protein (EGFP)—which is rapidly and transiently recruited at DNA damage sites—inhibits G2 arrest. Finally, γH2AX, p53‐binding protein 1, replication protein A and Rad51 foci are present for a prolonged period and clonogenic survival is decreased in PNUTS‐depleted cells after ionizing radiation treatment. We identify the PP1c regulatory subunit PNUTS as a new and integral component of the DNA damage response involved in DNA repair.
Crystal structures of human caspase 6 reveal a new mechanism for intramolecular cleavage self‐activation
Authors: Wang Xiao‐Jun , Cao Qin , Liu Xiang , Wang Kai‐Tuo , Mi Wei , Zhang Yan , Li Lan‐Fen , LeBlanc Andrea C , Su Xiao‐Dong
Published: October 2010

Dimeric effectors caspase 3 and caspase 7 are activated by initiator caspase processing. In this study, we report the crystal structures of effector caspase 6 (CASP6) zymogen and N‐Acetyl‐Val‐Glu‐Ile‐Asp‐al‐inhibited CASP6. Both of these forms of CASP6 have a dimeric structure, and in CASP6 zymogen the intersubunit cleavage site 190TEVD193 is well structured and inserts into the active site. This positions residue Asp 193 to be easily attacked by the catalytic residue Cys 163. We demonstrate biochemically that intramolecular cleavage at Asp 193 is a prerequisite for CASP6 self‐activation and that this activation mechanism is dependent on the length of the L2 loop. Our results indicate that CASP6 can be activated and regulated through intramolecular self‐cleavage.
Hearing Loss Is Negatively Related to Episodic and Semantic Long-Term Memory but Not to Short-Term Memory
Authors: Rönnberg Jerker , Danielsson Henrik , Rudner Mary , Arlinger Stig , Sternäng Ola , Wahlin Åke , Nilsson Lars-Göran
Published: October 2010

Purpose

To test the relationship between degree of hearing loss and different memory systems in hearing aid users.

Method

Structural equation modeling (SEM) was used to study the relationship between auditory and visual acuity and different cognitive and memory functions in an age-hetereogenous subsample of 160 hearing aid users without dementia, drawn from the Swedish prospective cohort aging study known as Betula (L.-G. Nilsson et al., 1997).

Results

Hearing loss was selectively and negatively related to episodic and semantic long-term memory (LTM) but not short-term memory (STM) performance. This held true for both ears, even when age was accounted for. Visual acuity alone, or in combination with auditory acuity, did not contribute to any acceptable SEM solution.

Conclusions

The overall relationships between hearing loss and memory systems were predicted by the ease of language understanding model (J. Rönnberg, 2003), but the exact mechanisms of episodic memory decline in hearing aid users (i.e., mismatch/disuse, attentional resources, or information degradation) remain open for further experiments. The hearing aid industry should strive to design signal processing algorithms that are cognition friendly.
The Effect of Listener Experience and Anchors on Judgments of Dysphonia
Authors: Eadie Tanya L. , Kapsner-Smith Mara
Published: October 2010

Purpose

To determine the effect of auditory anchors on judgments of overall severity (OS) and vocal effort (VE) in dysphonic speech when judgments are made by experienced and inexperienced listeners, and when self-rated by individuals with dysphonia (speaker–listeners).

Method

Twenty individuals with dysphonia and 4 normal controls provided speech recordings. Speaker–listeners judged their own speech samples for OS and VE without auditory anchors, and then in the presence of anchors, using 100-mm visual analog scales (VAS). Twenty inexperienced and 10 experienced listeners evaluated the same speech samples for OS and VE in similar rating conditions. Twenty inexperienced listeners also made judgments of the speech samples solely in anchored conditions.

Results

All listeners judged the speech samples as significantly less severe and effortful in the anchored conditions. No significant effects of anchors or experience were found for intrarater agreement within 7.14 mm on the VAS. Both inexperienced and experienced listeners were significantly less variable and showed improved interrater agreement in the anchored conditions. Anchors significantly improved agreement across groups of listeners, particularly between inexperienced and speaker–listeners.

Conclusion

Listeners systematically shift judgments of voice quality in response to auditory anchors. Anchors reduce interrater variability and may improve agreement across some types of listeners.
On-chip antibody immobilization for on-demand and rapid immunoassay on a microfluidic chip
Authors: Ohashi Toshinori , Mawatari Kazuma , Kitamori Takehiko
Published: October 2010

Immunoassay is one of the important applications of microfluidic chips and many methodologies were reported for decreasing sample/reagent volume, shortening assay time, and so on. Micro-enzyme-linked immunosorbent assay (micro-ELISA) is our method that utilizes packed microbeads in the microfluidic channel and the immunoreactions are induced on the beads surface. Due to the large surface-to-volume ratio and small analytical volume, excellent performances have been verified in assay time and sample/reagent volume. In order to realize the micro-ELISA, one of the important processes is the immobilization of antibody on the beads surface. Previously, the immobilization process was performed in a macroscale tube by physisorption of antibody, and long time (2 h) and large amount of antibody (or high concentration) were required for the immobilization. In addition, the processes including the reaction and washing were laborious, and changing the analyte was not easy. In this research, we integrated the immobilization process into a microfluidic chip by applying the avidin-biotin surface chemistry. The integration enabled very fast (1 min) immobilization with very small amount of precious antibody consumption (100 ng) for one assay. Because the laborious immobilization process can be automatically performed on the microfluidic chip, ELISA method became very easy. On-demand immunoassay was also possible just by changing the antibodies without using large amount of precious antibodies. Finally, the analytical performance was investigated by measuring C-reactive protein and good performance (limit of detection <20 ng/ml) was verified.
Wavelengths, Transition Probabilities, and Energy Levels for the Spectrum of Neutral Strontium (SrI)
Authors: Sansonetti J. E. , Nave G.
Published: October 2010

Following a critical review of spectroscopic data for neutral strontium (Z=38), the energy levels, with designations and uncertainties, have been tabulated. Wavelengths with classifications, intensities, and transition probabilities have also been reviewed. In addition, the 5s S1∕22, 4d D3∕22, and 4d D5∕22 ionization energies have been listed. A summary of the current state of measurements of the SrI 5s2 S01-5s5p P0∘3, F=9∕2 atomic clock transition, and other isotopic observations has also been included.
IUPAC-NIST Solubility Data Series. 88. Esters with Water-Revised and Updated. Part 4. C10 to C32 Esters
Authors: Mączyński Andrzej , Wiśniewska-Gocłowska Barbara
Published: October 2010

The mutual solubilities and related liquid-liquid equilibria of 46 binary systems of C10 to C32 esters with water are exhaustively and critically reviewed. Reports of experimental determination of solubility that appeared in the primary literature prior to the end of 2007 are compiled. For 13 systems, sufficient data are available to allow critical evaluation. All data are expressed as mass fraction and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a method based on the evaluation of all experimental data for a given series of esters was used.
Gold nanoparticle-assisted single base-pair mismatch discrimination on a microfluidic microarray device
Authors: Wang Lin , Li Paul C. H.
Published: October 2010

Two simple gold nanoparticle (GNP)-based DNA analysis methods using a microfluidic device are presented. In the first method, probe DNA molecules are immobilized on the surface of a self-assembled submonolayer of GNPs. The hybridization efficiency of the target oligonulceotides was improved due to nanoscale spacing between probe molecules. In the second method, target DNA molecules, oligonulceotides or polymerase chain reaction (PCR) amplicons, are first bound to GNPs and then hybridized to the immobilized probe DNA on a glass slide. With the aid of GNPs, we have successfully discriminated, at room temperature, between two PCR amplicons (derived from closely related fungal pathogens, Botrytis cinerea and Botrytis squamosa) with one base-pair difference. DNA analysis on the microfluidic chip avoids the use of large sample volumes, and only a small amount of oligonucelotides (8 fmol) or PCR products (3 ng), was needed in the experiment. The whole procedure was accomplished at room temperature in 1 h, and apparatus for high temperature stringency was not required.
Elastic Cross Sections for Electron Collisions with Molecules Relevant to Plasma Processing
Authors: Yoon J.-S. , Song M.-Y. , Kato H. , Hoshino M. , Tanaka H. , Brunger M. J. , Buckman S. J. , Cho H.
Published: October 2010

Absolute electron-impact cross sections for molecular targets, including their radicals, are important in developing plasma reactors and testing various plasma processing gases. Low-energy electron collision data for these gases are sparse and only the limited cross section data are available. In this report, elastic cross sections for electron-polyatomic molecule collisions are compiled and reviewed for 17molecules relevant to plasma processing. Elastic cross sections are essential for the absolute scale conversion of inelastic cross sections, as well as for testing computational methods. Data are collected and reviewed for elastic differential, integral, and momentum transfer cross sections and, for each molecule, the recommended values of the cross section are presented. The literature has been surveyed through early 2010.
Instability growth rate of two-phase mixing layers from a linear eigenvalue problem and an initial-value problem
Authors: Bagué Anne , Fuster Daniel , Popinet Stéphane , Scardovelli Ruben , Zaleski Stéphane
Published: October 2010

The temporal instability of parallel two-phase mixing layers is studied with a linear stability code by considering a composite error function base flow. The eigenfunctions of the linear problem are used to initialize the velocity and volume fraction fields for direct numerical simulations of the incompressible Navier–Stokes equations with the open-source GERRIS flow solver. We compare the growth rate of the most unstable mode from the linear stability problem and from the simulation results at moderate and large density and viscosity ratios in order to validate the code for a wide range of physical parameters. The efficiency of the adaptive mesh refinement scheme is also discussed.
Flow of ferrofluid in an annular gap in a rotating magnetic field
Authors: Chaves Arlex , Torres-Diaz Isaac , Rinaldi Carlos
Published: October 2010

An asymptotic solution is obtained for flow of a ferrofluid between two stationary coaxial cylinders of infinite extent, including the effects of spin viscosity. This solution takes into account the nonuniformity of the magnetic field in the annular space that arises as a consequence of the demagnetizing field of the inner cylinder. In the limit of zero spin viscosity the analysis predicts there is no flow in the annular gap. For nonzero spin viscosity the analysis predicts flow in the annulus with corotation of field and fluid close to the outer cylinder wall and counter-rotation close to the inner cylinder wall. The asymptotic predictions for the translational velocity are compared to experimental measurements obtained using the ultrasound velocity profile method for ferrofluid in an annular gap. The observed experimental velocity profiles are in qualitative agreement with the predictions of the asymptotic model, and transition between corotation to counter-rotation of fluid and field was observed at an intermediate radial position. These observations provide further evidence of the existence of couple stresses in ferrofluids and the importance of spin viscosity in describing some ferrofluid flows.
Measurement of ultralow loss in antireflection mirror
Authors: Chen Xinwei , Qiu Fusheng , Zhang Hongxia , Jia Dagong , Liu Tiegen , Zhang Yimo
Published: October 2010

A new method based on the double-beam polarization balance bridge technique for measuring the ultralow total loss, including absorption, scattering, and reflection in ultrahigh antireflection mirror is presented. By rotating the polarizer before and after the insertion of a mirror into one beam out of the Wollaston prism to adjust the intensities of the two beams to be equal, the total loss can be obtained by recording the angle variation of the polarizer. The factors affecting the measurement precision of the technique and the main sources of errors are investigated in detail. The total loss measurement precision of the mirror is 10 ppm and the zero drift is 10 ppm at 632.8 nm.
A broadband low-reflection metamaterial absorber
Authors: Gu S. , Barrett J. P. , Hand T. H. , Popa B.-I. , Cummer S. A.
Published: October 2010

Artificially engineered metamaterials have enabled the creation of electromagnetic materials with properties not found in nature. Recent work has demonstrated the feasibility of developing high performance, narrowband electromagnetic absorbers using such metamaterials. These metamaterials derive their absorption properties primarily through dielectric loss and impedance matching at resonance. This paper builds on that work by increasing the bandwidth through embedding resistors into the metamaterial structure in order to lower the Q factor and by using multiple elements with different resonances. This is done while maintaining an impedance-matched material at normal incidence. We thus present the design, simulation, and experimental verification of a broadband gigahertz region metamaterial absorber, with a maximum absorption of 99.9% at 2.4 GHz, and a full width at half maximum bandwidth of 700 MHz, all while maintaining low reflection inside and outside of resonance.
Characterizing chaotic melodies in automatic music composition
Authors: Coca Andrés E. , Tost Gerard O. , Zhao Liang
Published: October 2010

In this paper, we initially present an algorithm for automatic composition of melodies using chaotic dynamical systems. Afterward, we characterize chaotic music in a comprehensive way as comprising three perspectives: musical discrimination, dynamical influence on musical features, and musical perception. With respect to the first perspective, the coherence between generated chaotic melodies (continuous as well as discrete chaotic melodies) and a set of classical reference melodies is characterized by statistical descriptors and melodic measures. The significant differences among the three types of melodies are determined by discriminant analysis. Regarding the second perspective, the influence of dynamical features of chaotic attractors, e.g., Lyapunov exponent, Hurst coefficient, and correlation dimension, on melodic features is determined by canonical correlation analysis. The last perspective is related to perception of originality, complexity, and degree of melodiousness (Euler’s gradus suavitatis) of chaotic and classical melodies by nonparametric statistical tests.
Effective long-time phase dynamics of limit-cycle oscillators driven by weak colored noise
Authors: Nakao Hiroya , Teramae Jun-nosuke , Goldobin Denis S. , Kuramoto Yoshiki
Published: October 2010

An effective white-noise Langevin equation is derived that describes long-time phase dynamics of a limit-cycle oscillator driven by weak stationary colored noise. Effective drift and diffusion coefficients are given in terms of the phase sensitivity of the oscillator and the correlation function of the noise, and are explicitly calculated for oscillators with sinusoidal phase sensitivity functions driven by two typical colored Gaussian processes. The results are verified by numerical simulations using several types of stochastic or chaotic noise. The drift and diffusion coefficients of oscillators driven by chaotic noise exhibit anomalous dependence on the oscillator frequency, reflecting the peculiar power spectrum of the chaotic noise.
Quantitative evaluation of single-shot inline phase contrast imaging using an inverse compton x-ray source
Authors: Oliva P. , Carpinelli M. , Golosio B. , Delogu P. , Endrizzi M. , Park J. , Pogorelsky I. , Yakimenko V. , Williams O. , Rosenzweig J.
Published: October 2010

Inverse compton scattering (ICS) x-ray sources are of current interest in biomedical imaging. We present an experimental demonstration of inline phase contrast imaging using a single picosecond pulse of the ICS source located at the BNL Accelerator Test Facility. The phase contrast effect is clearly observed. Its qualities are shown to be in agreement with the predictions of theoretical models through comparison of experimental and simulated images of a set of plastic wires of differing composition and size. Finally, we display an application of the technique to a biological sample, confirming the possibility of time-resolved imaging on the picosecond scale.
Communication: Heavy Rydberg states: The H+H− system
Authors: Kirrander Adam
Published: October 2010

Heavy Rydberg states are analogs of electronic Rydberg states, but with the electron replaced by a much heavier ion. We calculate ab initio the extremely long-range vibrational H+H− heavy Rydberg states in H2, and compare these to recent experiments. The calculated resonance positions and widths agree well with experiment, but we predict additional sharp interloper resonances corresponding to vibrational states trapped inside the barrier on potential energy curve 7 Σ1g+.
Surface patterning of bonded microfluidic channels
Authors: Priest Craig
Published: October 2010

Microfluidic channels in which multiple chemical and biological processes can be integrated into a single chip have provided a suitable platform for high throughput screening, chemical synthesis, detection, and alike. These microchips generally exhibit a homogeneous surface chemistry, which limits their functionality. Localized surface modification of microchannels can be challenging due to the nonplanar geometries involved. However, chip bonding remains the main hurdle, with many methods involving thermal or plasma treatment that, in most cases, neutralizes the desired chemical functionality. Postbonding modification of microchannels is subject to many limitations, some of which have been recently overcome. Novel techniques include solution-based modification using laminar or capillary flow, while conventional techniques such as photolithography remain popular. Nonetheless, new methods, including localized microplasma treatment, are emerging as effective postbonding alternatives. This Review focuses on postbonding methods for surface patterning of microchannels.
Preface to Special Topic: Surface Modification, Wetting, and Biological Interfaces (Guest Editors: John Ralston and Jingfang Zhou)
Authors: Ralston John , Zhou Jingfang
Published: October 2010

This Special Topic section of Biomicrofluidics on “Surface Modification, Wetting, and Biological Interfaces,” is discussed. The topic is very timely and one that is tremendously relevant to the microfluidics and nanofluidics community.
Multidomain ferroelectricity as a limiting factor for voltage amplification in ferroelectric field-effect transistors
Authors: Cano A. , Jiménez D.
Published: October 2010

We revise the possibility of having an amplified surface potential in ferroelectric field-effect transistors pointed out by [S. Salahuddin and S. Datta, Nano Lett. 8, 405 (2008)]. We show that the negative-capacitance regime that allows for such amplification is actually bounded by the appearance of multidomain ferroelectricity. This imposes a severe limit to the maximum step-up of the surface potential obtainable in the device. We indicate new device design rules taking into account this scenario.
SrTiO
3
thin film capacitors on silicon substrates with insignificant interfacial passive layers
Authors: Schmelzer S. , Bräuhaus D. , Hoffmann-Eifert S. , Meuffels P. , Böttger U. , Oberbeck L. , Reinig P. , Schröder U. , Waser R.
Published: October 2010

Using sputter deposition, nonepitaxial ultrathin film capacitors consisting of SrRuO3 electrodes and dielectric SrTiO3 (STO) were grown directly on oxidized silicon substrates. The surface roughness of the layers was found to be very low (≲0.2 nm). Dielectric measurements as a function of temperature were performed on samples with different STO thickness down to 7 nm, showing temperature dependence of the interfacial passive layers. The dielectric constant of the STO films was found to be in the range of 200 at room temperature for all samples, which leads to a minimum capacitance equivalent thickness below 0.2 nm.
Voltage tunable short wire-pair type of metamaterial infiltrated by nematic liquid crystal
Authors: Zhang Fuli , Zhao Qian , Zhang Weihong , Sun Jingbo , Zhou Ji , Lippens Didier
Published: October 2010

In this letter, we report an experimental demonstration on voltage tunable short wire-pair metamaterial with negative permeability at microwave frequencies. After infiltrated by nematic liquid crystal, magnetic resonance of short wire-pair can be effectively tuned via relatively low static electric field. The results show, by increasing bias voltage from 0 to 100 V, magnetic resonance is continuously and reversibly shifted from 9.91 down to 9.55 GHz. Moreover, the effective permeability of metamaterial, for operation frequency around magnetic resonance, varies from negative to positive values. Numerical analysis has a good agreement with experimental results.
Isotope ratios hint at a piece of pristine Earth
Authors: Miller Johanna
Published: October 2010

Could any material on Earth have remained isolated and undisturbed for 4.5 billion years? And if it did, how could we tell?
Putting quantum gases under the microscope
Authors: Levi Barbara Goss
Published: October 2010

Microscopes with single-site resolution are vital for using ultracold atoms to simulate strongly correlated electrons in solids.
Multiferroics: Past, present, and future
Authors: Spaldin Nicola A. , Cheong Sang-Wook , Ramesh Ramamoorthy
Published: October 2010

Working in concert, theorists and experimentalists have found promising new ways to get two traditional foes—ferroelectricity and magnetism—to coexist
Complexation of Zn2+ by the Fluorophore 2-((E)-2-Phenyl)ethenyl-8-(N-4-methylbenzenesulfonyl)aminoquinol-6-yloxyacetic Acid: A Preparative, Potentiometric, UV-visible, and Fluorescence Study
Authors: Coleman Hilary C. , May Bruce L. , Lincoln Stephen F.
Published: October 2010

The preparation of the Zn2+ specific fluorophore 2-((E)-2-phenyl)ethenyl-8-(N-4-methylbenzene-sulfonyl)aminoquinol-6-yloxyacetic acid, H23, is described. The protonated form, H33+, is characterized by pKa values of 2.71 ± 0.03, 4.92 ± 0.03, and 10.46 ± 0.03 in 25% (v/v) aqueous ethanol 0.10 mol L–1 in NaClO4 at 298.2 K determined by potentiometric titration. At pH 6.6, but otherwise under the same conditions, the dianion, 32–, forms the fluorescent complexes [Zn(3)] and [Zn(3)2]2–, characterized by log(K1/L mol–1) = 10.5 ± 0.20 and log(K2/L mol–1) = 11.1 ± 0.1, respectively, as determined by fluorimetry. These data are compared with analogous data for the structurally similar and widely used fluorophore 2-methyl-8-p-toluenesulfonamido-6-quinolyloxyacetic acid (Zinquin A).
Nucleic Acid (Calf Thymus-DNA, Yeast tRNA) Binding and Cytotoxic Properties of a Dinuclear (Ru,Co) Metal Polypyridyl Complex
Authors: Liang Xi-Ling , Tan Li-Feng
Published: October 2010

Based on [L2Ru{DPPZ(11–11′)DPPZ}RuL2]4+ (where L = 1,10-phenanthroline or 2,2′-bipyridyl, DPPZ(11–11′)DPPZ = 11,11′-bi(dipyrido-[3,2-a:2′,3′-c]-phenazinyl)), a heterodinuclear (Ru,Co) metal polypyridyl complex [(phen)2Ru{DPPZ(11–11′)DPPZ}Co(phen)2]5+ (phen = 1,10-phenanthroline) has been designed and synthesized. A comparative study on the interaction of the complex with calf thymus DNA and yeast tRNA was investigated by UV-visible spectroscopy, fluorescence spectroscopy and viscosity measurements, as well as equilibrium dialysis and circular dichroism. The antitumour activities of the complex were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetraazolium bromide method and Giemsa staining experiment. These results indicate that the configuration and structures of nucleic acids have significant effects on the binding behaviours of metal complexes. Furthermore, the complex shows different antitumour activities against selected tumour cell lines, and can cause cell apoptosis.
Novel Degradable Polymer Networks Containing Acetal Components and Well-Defined Backbones
Authors: Sui Xin-Ce , Shi Yan , Fu Zhi-Feng
Published: October 2010

A novel copolymer network was successfully prepared by combining the reversible addition–fragmentation chain-transfer polymerization (RAFT) and addition reaction between hydroxyl and vinyloxy groups. 2-Hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) were copolymerized in 1,4-dioxane with 2,2′-azobisisobutyronitrile as initiator and 2-(ethoxycarbonyl)prop-2-yl dithiobenzoate as a RAFT agent. The molecular weight of poly(HEMA-co-MMA) was well controlled and the polydispersity was low. The hydroxyl group from the HEMA unit in the copolymer underwent an addition reaction with 1,4-cyclohexanedimethanol divinyl ether in the presence of pyridinium p-toluenesulfonate, generating a copolymer network with an acetal component in the crosslinking segment. The crosslinking time depended on the molar ratio of HEMA and MMA in the poly(HEMA-co-MMA). After being treated in strong acid, the copolymer network was able to be degraded owing to the acetal structure, but the backbone chains of poly(HEMA-co-MMA) remained intact.
Retinol-binding protein (RBP), retinol and β-carotene in the bovine uterus and plasma during the oestrous cycle and the relationship between systemic progesteroneand RBP on Day 7
Authors: Costello Lisa M. , O'Boyle Padraic , Godkin James D. , Diskin Michael G. , Hynes Ailish C. , Morris Dermot G.
Published: October 2010

In the dairy cow, low systemic concentrations of progesterone are known to be a major factor associated with early embryo loss. Endometrial expression of the gene encoding retinol-binding protein (RBP) is sensitive to small changes in progesterone on Day 7 of the oestrous cycle. The objectives of the present study were to measure RBP concentrations in bovine uterine flushings and plasma across different days of the oestrous cycle and to examine the relationship between uterine RBP and systemic concentrations of progesterone. Uterine flushings and plasma were collected from cows on Days 3, 7, 11 and 15 of the oestrous cycle. Uterine RBP concentrations were five- to 15-fold higher (P < 0.001) on Day 15 compared with the other days and twofold higher (P < 0.001) in the uterine horn ipsilateral to the corpus luteum on Day 15. RBP concentrations were similar in flushings and plasma across Days 3–11; however, Day 15 RBP concentrations were six- to 15-fold higher (P < 0.001) in uterine flushings. No significant relationship was found between the concentration of systemic progesterone and RBP concentrations on Day 7. Overall, the results of the present study indicate a local controlling mechanism operating at the level of the endometrium to regulate RBP secretion, most likely progesterone.
Caffeine and dithiothreitol delay ovine oocyte ageing
Authors: Ye Xiao-Fang , Chen Shi-Bin , Wang Li-Qin , Zhao Yun-Cheng , Lv Xue-Feng , Liu Ming-Jun , Huang Jun-Cheng
Published: October 2010

The intracellular glutathione levels and developmental competence of aged oocytes after parthenogenetic activation, somatic cell nuclear transfer and intracytoplasmic sperm injection in the presence or absence of caffeine or dithiothreitol (DTT) were examined. The following results were found: (1) ovine oocytes were fully aged 30 h post-onset of maturation culture; (2) the appropriate concentrations of caffeine and DTT for oocyte culture were 5 mM and 1 mM, respectively; (3) when nuclear transfer-reconstructed embryos were treated with caffeine or DTT following fusion, no increase in the frequency of development to blastocyst was observed (P > 0.05), but the cell numbers of blastocysts increased (P < 0.05); (4) both caffeine and DTT increased the blastocyst formation rates of intracytoplasmic sperm-injected embryos (P < 0.05); (5) caffeine increased the glutathione content of aged oocytes (P < 0.05). The glutathione content of DTT-treated aged oocytes was higher than that of oocytes matured for 36 h (P < 0.05). In conclusion, caffeine and dithiothreitol delay oocyte ageing but only to a limited extent.
Identification of Perilipin-2 as a lipid droplet protein regulated in oocytes during maturation
Authors: Yang Xing , Dunning Kylie R. , Wu Linda L.-Y. , Hickey Theresa E. , Norman Robert J. , Russell Darryl L. , Liang Xiaoyan , Robker Rebecca L.
Published: October 2010

Lipid droplet proteins regulate the storage and utilisation of intracellular lipids. Evidence is emerging that oocyte lipid utilisation impacts embryo development, but lipid droplet proteins have not been studied in oocytes. The aim of the present study was to characterise the size and localisation of lipid droplets in mouse oocytes during the periovulatory period and to identify lipid droplet proteins as potential biomarkers of oocyte lipid content. Oocyte lipid droplets, visualised using a novel method of staining cumulus–oocyte complexes (COCs) with BODIPY 493/503, were small and diffuse in oocytes of preovulatory COCs, but larger and more centrally located after maturation in response to ovulatory human chorionic gonadotrophin (hCG) in vivo, or FSH + epidermal growth factor in vitro. Lipid droplet proteins Perilipin, Perilipin-2, cell death-inducing DNA fragmentation factor 45-like effector (CIDE)-A and CIDE-B were detected in the mouse ovary by immunohistochemistry, but only Perilipin-2 was associated with lipid droplets in the oocyte. In COCs, Perilipin-2 mRNA and protein increased in response to ovulatory hCG. IVM failed to induce Perilipin-2 mRNA, yet oocyte lipid content was increased in this context, indicating that Perilipin-2 is not necessarily reflective of relative oocyte lipid content. Thus, Perilipin-2 is a lipid droplet protein in oocytes and its induction in the COC concurrent with dynamic reorganisation of lipid droplets suggests marked changes in lipid utilisation during oocyte maturation.
Oocyte developmental competence is reduced in sows during the seasonal infertility period
Authors: Bertoldo M. , Holyoake P. K. , Evans G. , Grupen C. G.
Published: October 2010

The modern domestic sow exhibits a period of impaired reproductive performance during the late summer and early autumn months, known as ‘seasonal infertility’. A reduction in farrowing rate due to pregnancy loss is the most economically important manifestation of seasonal infertility. The aim of the present study was to determine whether there are changes in oocyte developmental competence associated with season. Ovaries were collected in pairs from sows sourced from commercial piggeries and slaughtered 4 days after weaning during winter and summer–autumn. Following oocyte IVM and parthenogenetic activation, the ability of oocytes from large follicles to form blastocysts was greater in winter (54.94 ± 6.11%) than in summer (21.09 ± 5.59%). During winter, the proportion of oocytes developing to the blastocyst stage from large follicles was significantly higher (54.94 ± 6.11%) than those oocytes from small follicles (23.17 ± 6.02%). There was no effect of season on the proportion of oocytes developing to the blastocyst stage from small follicles. There was no effect of follicle size on blastocyst formation from those oocytes recovered during summer. Blastocysts derived from small follicles during summer had the lowest number of cells (24.25 ± 1.48) compared with blastocysts derived from large follicles during winter (37.5 ± 1.3; P < 0.05). The mean progesterone concentration in follicular fluid collected from small follicles was greater in winter than summer (1235.55 ± 164.47 v. 701.3 ± 115.5 nmol L–1, respectively; P < 0.001). The mean progesterone concentration in the follicular fluid of large follicles was also greater in winter than in summer (2470.9 ± 169.1 v. 1469.2 ± 156.5 nmol L–1, respectively; P < 0.001). Regression analysis revealed a positive correlation between progesterone concentration and oocyte developmental competence. The results indicate that porcine oocytes fail to reach their full developmental potential during the period of seasonal infertility, suggesting that the pregnancy losses observed at this time of year may be due to reduced oocyte developmental competence.
Protein–ice interaction of an antifreeze protein observed with solid-state NMR
Authors: Siemer Ansgar B. , Huang Kuo-Ying , McDermott Ann E.
Published: October 2010

NMR on frozen solutions is an ideal method to study fundamental questions of macromolecular hydration, because the hydration shell of many biomolecules does not freeze together with bulk solvent. In the present study, we present previously undescribed NMR methods to study the interactions of proteins with their hydration shell and the ice lattice in frozen solution. We applied these methods to compare solvent interaction of an ice-binding type III antifreeze protein (AFP III) and ubiquitin a non-ice-binding protein in frozen solution. We measured1H-1H cross-saturation and cross-relaxation to provide evidence for a molecular contact surface between ice and AFP III at moderate freezing temperatures of -35 °C. This phenomenon is potentially unique for AFPs because ubiquitin shows no such cross relaxation or cross saturation with ice. On the other hand, we detected liquid hydration water and strong water–AFP III and water–ubiquitin cross peaks in frozen solution using relaxation filtered2H and HETCOR spectra with additional1H-1H mixing. These results are consistent with the idea that ubiquitin is surrounded by a hydration shell, which separates it from the bulk ice. For AFP III, the water cross peaks indicate that only a portion of its hydration shell (i.e., at the ice-binding surface) is in contact with the ice lattice. The rest of AFP III’s hydration shell behaves similarly to the hydration shell of non-ice-interacting proteins such as ubiquitin and does not freeze together with the bulk water.
Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large predatory fish
Authors: Dahl Tais W. , Hammarlund Emma U. , Anbar Ariel D. , Bond David P. G. , Gill Benjamin C. , Gordon Gwyneth W. , Knoll Andrew H. , Nielsen Arne T. , Schovsbo Niels H. , Canfield Donald E.
Published: October 2010

The evolution of Earth’s biota is intimately linked to the oxygenation of the oceans and atmosphere. We use the isotopic composition and concentration of molybdenum (Mo) in sedimentary rocks to explore this relationship. Our results indicate two episodes of global ocean oxygenation. The first coincides with the emergence of the Ediacaran fauna, including large, motile bilaterian animals, ca. 550–560 million year ago (Ma), reinforcing previous geochemical indications that Earth surface oxygenation facilitated this radiation. The second, perhaps larger, oxygenation took place around 400 Ma, well after the initial rise of animals and, therefore, suggesting that early metazoans evolved in a relatively low oxygen environment. This later oxygenation correlates with the diversification of vascular plants, which likely contributed to increased oxygenation through the enhanced burial of organic carbon in sediments. It also correlates with a pronounced radiation of large predatory fish, animals with high oxygen demand. We thereby couple the redox history of the atmosphere and oceans to major events in animal evolution.
Is Frequentist Testing Vulnerable to the Base-Rate Fallacy?
Authors: Spanos Aris
Published: October 2010

This article calls into question the charge that frequentist testing is susceptible to the base-rate fallacy. It is argued that the apparent similarity between examples like the Harvard Medical School test and frequentist testing is highly misleading. A closer scrutiny reveals that such examples have none of the basic features of a proper frequentist test, such as legitimate data, hypotheses, test statistics, and sampling distributions. Indeed, the relevant error probabilities are replaced with the false positive/negative rates that constitute deductive calculations based on known probabilities among events. As a result, the ampliative dimension of frequentist induction—learning from data about the underlying data-generating mechanism—is missing.
Can the Best-Alternative Justification Solve Hume's Problem? On the Limits of a Promising Approach
Authors: Arnold Eckhart
Published: October 2010

In a recent Philosophy of Science article, Gerhard Schurz proposes meta-inductivistic prediction strategies as a new approach to Hume's problem. This discussion examines the limitations of Schurz's approach. It can be proved that the meta-inductivistic approach does not work anymore if meta-inductivists have to face an infinite number of alternative predictors. With this limitation it remains doubtful whether the meta-inductivist can provide a full solution to the problem of induction.
Dermal mast cells reduce progressive tissue necrosis caused by subcutaneous infection with Streptococcus pyogenes in mice
Authors: Matsui Hidenori , Sekiya Yukie , Takahashi Tetsufumi , Nakamura Masahiko , Imanishi Ken'ichi , Yoshida Haruno , Murayama Somay Yamagata , Takahashi Takashi , Tsuchimoto Kanji , Uchiyama Takehiko , Ubukata Kimiko
Published: October 2010

A single subcutaneous (s.c.) infection with 1×107 c.f.u. GAS472, a group A streptococcus (GAS) serotype M1 strain isolated from the blood of a patient suffering from streptococcal toxic shock syndrome, led to severe damage of striated muscle layers in the feet of mast cell (MC)-deficient WBB6F1-KitW/KitW-v
(W/Wv
) mice 72 h after infection. In contrast, no damage was recognized in striated muscle layers in the feet of the control WBB6F1-Kit
+/+ (+/+) mice 72 h after infection. In addition, adoptively transferred MCs reduced progressive tissue necrosis of the feet of W/Wv
mice after infection. However, there was no significant difference in the mortality rates between the W/Wv
and +/+ mice, or between the human CD46-expressing transgenic (Tg) mouse bone marrow-derived cultured MC-reconstituted W/Wv
and non-Tg mouse bone marrow-derived cultured MC-reconstituted W/Wv
mice after infection. Consequently, although MCs can help to reduce the severity of necrosis of the feet caused by s.c. infection with GAS472, such reduction of tissue necrosis scarcely improves the mortality rates of these mice. Moreover, human CD46 does not play a crucial role in the MC-mediated innate immune defence against GAS infection.
Drug sensitivity and clinical impact of members of the genus Kocuria
Authors: Savini Vincenzo , Catavitello Chiara , Masciarelli Gioviana , Astolfi Daniela , Balbinot Andrea , Bianco Azaira , Febbo Fabio , D'Amario Claudio , D'Antonio Domenico
Published: October 2010

Organisms in the genusKocuriaare Gram-positive, coagulase-negative, coccoid actinobacteria belonging to the familyMicrococcaceae, suborderMicrococcineae, orderActinomycetales. Sporadic reports in the literature have dealt with infections byKocuriaspecies, mostly in compromised hosts with serious underlying conditions. Nonetheless, the number of infectious processes caused by such bacteria may be higher than currently believed, given that misidentification by phenotypic assays has presumably affected estimates of the prevalence over the years. As a further cause for concern, guidelines for therapy of illnesses involvingKocuriaspecies are lacking, mostly due to the absence of established criteria for evaluatingKocuriareplication or growth inhibition in the presence of antibiotics. Therefore, breakpoints for staphylococci have been widely used throughout the literature to try to understand this pathogen's behaviour under drug exposure; unfortunately, this has sometimes created confusion, thus higlighting the urgent need for specific interpretive criteria, along with a deeper investigation into the resistance determinants within this genus. We therefore review the published data on cultural, genotypic and clinical aspects of the genusKocuria, aiming to shed some light on these emerging nosocomial pathogens.
Prevalent genotypes of meticillin-resistant Staphylococcus aureus: report from Pakistan
Authors: Zafar A. , Stone M. , Ibrahim S. , Parveen Z. , Hasan Z. , Khan E. , Hasan R. , Wain J. , Bamford K.
Published: October 2010

Meticillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen in Pakistan and is emerging in the community. This is one of the first reports of the prevalent genotypes of MRSA in both hospital and community settings in Pakistan. Isolates collected in 2006–2007 were characterized by PFGE, staphylococcal cassette chromosome mec (SCCmec) typing and multilocus sequence typing (MLST). PFGE identified nine pulsotypes, the majority of isolates belonging to pulsotypes A (n=70) and B (n=38), which were predominant among hospital-onset MRSA (HO-MRSA) and community-onset MRSA (CO-MRSA) isolates, respectively. Among the HO-MRSA isolates, variants of SCCmec type III were prevalent, whilst SCCmec type IV or variants were predominant in the CO-MRSA isolates. MLST identified two principal sequence types, ST8 and ST239. An association was observed between ST8, PFGE pulsotype B and SCCmec type IV in the CO-MRSA (ST8-MRSA-IV). Similarly, ST239, PFGE pulsotype A and SCCmec type III were associated with HO-MRSA (ST239-MRSA-III). Therefore, the prevalent genotypes circulating in Pakistan at the time of study were ST8-MRSA-IV and ST239-MRSA-III in the community and hospital settings, respectively. A set of HO-MRSA isolates collected in 1997 were characterized by PFGE and SCCmec typing for comparison. The isolates belonged to two PFGE pulsotypes (A, n=28; B, n=11) and contained just two SCCmec types. These results suggest that an increase in genetic diversity occurred over the period 1997–2007 as a result of either microevolution or the importation of strains from surrounding areas.