bluuebunny/crossref_metadata_2025_split huggingface dataset:
Results of magnetic field observations of stars with helium anomalies with the 6‐m telescope
Authors: Yakunin I. , Romanyuk I. , Kudryavtsev D. , Semenko E. 
Published: December 2011

AbstractWe present new longitudinal magnetic field observations of hot CP stars with helium anomalies obtained on 6‐m telescope at years 2010 and 2011. The survey includes more than 30 objects. For 8 stars magnetic field was detected for the first time. For 2 previously known magnetic stars HD 36485 and HD 35298 circular polarized spectra were obtained at different phases of the period. Both stars show lines with non‐usual complicated distribution of Stokes V which is changing strongly during their rotation (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Speckle interferometry of magnetic Ap/Bp stars at the BTA 6‐m telescope (new binary and multiple systems)
Authors: Balega Y.Y. , Dyachenko V.V. , Maksimov A.F. , Malogolovets E.V. , Rastegaev D.A. , Romanyuk I.I. 
Published: December 2011

AbstractWe report the results of speckle interferometric observations of 117 Ap/Bp stars made with the 6‐m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences in December 2009. We resolved 27 binary and 2 triple stars into individual components. Fourteen of these stars were astrometrically resolved for the first time. The fraction of speckle interferometric binaries in the sample of 117 Ap/Bp stars with confirmed magnetic fields is 25%. We expect that the total fraction of binaries in the sample with account for spectroscopic short‐period systems and astrometric common proper motion pairs can be twice higher (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Statistics of magnetic fields and fluxes of massive OB stars and the origin of neutron star magnetic fields
Authors: Igoshev A.P. , Kholtygin A.F. 
Published: December 2011

AbstractBased on the newest measurements, statistical properties of rms mean magnetic fields of OB and neutron stars (NSs) were investigated. The magnetic field distribution function f (B) for OB stars was determined and a sharp decrease of f (B) for weak magnetic fields was found. The mean magnetic fluxes F for all massive stars and NSs with measured magnetic fields was estimated, and it was found that log F = 27.7 for OB stars and log F = 24.5 for NSs. To explain the large differences of the fluxes from normal and neutron stars we studied the birth and evolution of isolated neutron stars in the whole volume of our Galaxy with our new code of population synthesis. We started modeling the birth of massive OB stars and followed their motion within the spiral arms to the point of supernova explosion. Next we considered the evolution of NS up to the death line with considering the magnetic field decay. We found that a significant magnetic field decay occurs during the first million years of a NS's life. We have estimated the mean time of the Ohmic decay for NS. We modeled the distributions of pulsar periods P, of period derivatives $ \dot P $, and of pulsar magnetic fields B, and found that they are in a good agreement with those taken from ATNF Pulsar Catalogue (Manchester et al. 2005) (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of stratification in spherical shell convection
Authors: Käpylä P.J. , Mantere M.J. , Brandenburg A. 
Published: December 2011

AbstractWe report on simulations of mildly turbulent convection in spherical wedge geometry with varying density stratification. We vary the density contrast within the convection zone by a factor of 20 and study the influence of rotation on the solutions. We demonstrate that the size of convective cells decreases and the anisotropy of turbulence increases as the stratification is increased. Differential rotation is found to change from anti‐solar (slow equator) to solar‐like (fast equator) at roughly the same Coriolis number for all stratifications. The largest stratification runs, however, are sensitive to changes of the Reynolds number. Evidence for a near‐surface shear layer is found in runs with strong stratification and large Reynolds numbers (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shock formation around planets orbiting M‐dwarf stars
Authors: Vidotto A.A. , Llama J. , Jardine M. , Helling Ch. , Wood K. 
Published: December 2011

AbstractBow shocks can be formed around planets due to their interaction with the coronal medium of the host stars. The net velocity of the particles impacting on the planet determines the orientation of the shock. At the Earth's orbit, the (mainly radial) solar wind is primarily responsible for the formation of a shock facing towards the Sun. However, for close‐in planets that possess high Keplerian velocities and are frequently located at regions where the host star's wind is still accelerating, a shock may develop ahead of the planet. If the compressed material is able to absorb stellar radiation, then the signature of bow shocks may be observed during transits. Bow‐shock models have been investigated in a series of papers (Llama et al. 2011; Vidotto et al. 2010, 2011a,b) for known transiting systems. Once the signature of a bow‐shock is observed, one can infer the magnetic field intensity of the transiting planet. Here, we investigate the potential to use this model to detect magnetic fields of (hypothetical) planets orbiting inside the habitable zone of M‐dwarf stars. For these cases, we show, by means of radiative transfer simulations, that the detection of bow‐shocks of planets surrounding M‐dwarf stars may be more difficult than for the case of close‐in giant planets orbiting solar‐type stars (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of turbulent pumping on stellar activity cycles
Authors: Do Cao O. , Brun A.S. 
Published: December 2011

AbstractStellar magnetic activity of solar like stars is thought tobe due to an internal dynamo. While the Sun has been the subject of intense research for refining dynamo models, observations of magnetic cyclic activity in solar type stars have become more and more available, opening a new path to understand the underlying physics behind stellar cycles. For instance, it is key to understand how stellar rotation rate influences magnetic cycle period Pcyc. Recent numerical simulations of advection‐dominated Babcock Leighton models have demonstrated that it is difficult to explain this observed trend given a) the strong influence of the cycle period to the meridional circulation amplitude and b) the fact that 3D models indicate that meridional flows become weaker as the rotation rate increases. In this paper, we introduce the turbulent pumping mechanism as another advective process capable also of transporting the magnetic fields. We found that this model is now able to reproduce the observations under the assumption that this effect increases as Ω2. The turbulent pumping becomes indeed another major player able to circumvent the meridional circulation. However, for high rotation rates (Ω ≃ 5Ω⊙), its effects dominate those of the meridional circulation, entering a new class of regime dominated by the advection of turbulent pumping and thus leading to a cyclic activity qualitatively different from that of the Sun (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flow injection chemiluminescence determination of vitamin B12 using on‐line UV‐persulfate photooxidation and charge coupled device detection
Authors: Murillo Pulgarín José A. , García Bermejo Luisa F. , Nieves Sánchez García M. 
Published: December 2011

ABSTRACTA sensitive chemiluminescence method for vitamin B12 using a charge‐coupled device (CCD) photodetector combined with on‐line UV‐persulfate oxidation in a simple continuous flow system has been developed. The principle for the determination of vitamin B12 is based on the enhancive effect of cobalt (II) on the chemiluminescence reaction between luminol and percarbonate in alkaline medium. In addition, percarbonate has been investigated and proposed as a powerful source of hydrogen peroxide as oxidant agent in this chemiluminescence reaction. The digestion of vitamin B12 to release the cobalt (II) is reached by UV irradiation treatment in a persulfate medium. The CCD detector, directly connected to the flow cell, is used with the continuous flow manifold to obtain the full spectral characteristics of cobalt (II) catalyzed luminol–percarbonate reaction. The vitamin B12 oxidation process and chemical conditions for the chemiluminescence reaction were investigated and optimized. The increment of the emission intensity was proportional to the concentration of vitamin B12, giving a second‐order calibration graph over the cobalt (II) concentration range from 10 to 5000 μg L−1 (r2 = 0.9985) with a detection limit of 9.3 μg L−1. The proposed method was applied to the determination of vitamin B12 in different kinds of pharmaceuticals. Copyright © 2011 John Wiley & Sons, Ltd.
Bioluminescent enzyme assay for the indication of plant stress in enclosed life support systems
Authors: Kratasyuk Valentina , Esimbekova Elena , Correll Melanie , Bucklin Ray 
Published: December 2011

ABSTRACTThe application of bioluminescent sensors for monitoring key metabolites and enzymes that are indicators of stress in plants is demonstrated. The sensitivity of bioluminescent assay for NAD(P)H and NAD(P)+ was about 0.5 and 1 nmol, respectively. The levels of NAD(P)H and NAD(P)+ in radish (Raphanus sativus) root extracts from controls and from stress‐induced conditions were compared. To induce environmental stress, the plants were grown in enclosed environmental chambers with low pressure (9 or 32 kPa), high humidity (>80%) and low oxygen partial pressure (down to 3.3–6.5 kPa). The concentrations of NAD(P)+ and NAD(P)H in plants varied under stress conditions. Decreasing both total pressure from 101.5 to 32 or 9 kPa and partial pressure of oxygen increased the ratio of NAD(P)+/NAD(P)H from 0.2 to 4 or 6, respectively. The increase in this ratio suggests that plants are undergoing stress in these hypobaric environments. The developed bioluminescent assay for quantification of pyridine nucleotides in plant tissues is rapid, low‐cost and easily performed. Copyright © 2011 John Wiley & Sons, Ltd.
Immobilization of lipase B from Candida antarctica on porous styrene–divinylbenzene beads improves butyl acetate synthesis
Authors: Graebin Natália G. , Martins Andréa B. , Lorenzoni André S. G. , Garcia‐Galan Cristina , Fernandez‐Lafuente Roberto , Ayub Marco A. Z. , Rodrigues Rafael C. 
Published: December 2011

AbstractA new biocatalyst of lipase B from Candida antarctica (MCI‐CALB) immobilized on styrene–divinylbenzene beads (MCI GEL CHP20P) was compared with the commercial Novozym 435 (immobilized lipase) in terms of their performances as biocatalysts for the esterification of acetic acid and n‐butanol. The effects of experimental conditions on reaction rates differed for each biocatalyst, showing different optimal values for water content, temperature, and substrate molar ratio. MCI‐CALB could be used at higher acid concentrations, up to 0.5 M, while Novozym 435 became inactivated at these acid concentrations. Although Novozym 435 exhibited 30% higher initial activity than MCI‐CALB for the butyl acetate synthesis, the reaction course was much more linear using the new preparation, meaning that the MCI‐CALB allows for higher productivities per cycle. Both preparations produced around 90% of yield conversions after only 2 h of reaction, using 10% (mass fraction) of enzyme. However, the main advantage of the new biocatalyst was the superior performance during reuse. While Novozym 435 was fully inactivated after only two batches, MCI‐CALB could be reused for six consecutive cycles without any washings and keeping around 70% of its initial activity. It is proposed that this effect is due to the higher hydrophobicity of the new support, which does not retain water or acid in the enzyme environment. MCI‐CALB has shown to be a very promising biocatalyst for the esterification of small‐molecule acids and alcohols. © 2012 American Institute of Chemical Engineers Biotechnol. Prog.,, 2012
Enzymatic Recognition of 2′‐Modified Ribonucleoside 5′‐Triphosphates: Towards the Evolution of Versatile Aptamers
Authors: Lauridsen Lasse H. , Rothnagel Joseph A. , Veedu Rakesh N. 
Published: December 2011

AbstractThe quest for effective, selective and nontoxic nucleic‐acid‐based drugs has led to designing modifications of naturally occurring nucleosides. A number of modified nucleic acids have been made in the past decades in the hope that they would prove useful in target‐validation studies and therapeutic applications involving antisense, RNAi, aptamer, and ribozyme‐based technologies. Since their invention in the early 1990s, aptamers have emerged as a very promising class of therapeutics, with one drug entering the market for the treatment of age‐related macular degeneration. To combat the limitations of aptamers containing naturally occurring nucleotides, chemically modified nucleotides have to be used. In order to apply modified nucleotides in aptamer drug development, their enzyme‐recognition capabilities must be understood. For this purpose, several modified nucleoside 5′‐triphosphates were synthesized and investigated as substrates for various enzymes. Herein, we review studies on the enzyme‐recognition of various 2′‐sugar‐modified NTPs that were carried out with a view to their effective utilization in SELEX processes to generate versatile aptamers.
Novel Cell‐Penetrating Peptides Based on α‐Aminoxy Acids
Authors: Ma Yilong , Yang Dongmei , Ma Yan , Zhang Yu‐Hui 
Published: December 2011

AbstractThe remarkable ability of cell‐penetrating peptides (CPPs) to deliver cell‐impermeable compounds into living cells makes them attractive transporters for use in biology and medicine. Despite their highly efficient cellular uptake, CPPs consisting of natural amino acids always suffer from degradation and endosomal entrapment, thereby greatly limiting their application in vivo. Here, we describe the preparation of novel CPPs incorporating α‐aminoxy acid residues and their cellular uptake behavior. We demonstrate that introducing α‐aminoxy acids into the backbones of CPPs enhances their diffuse cytosolic distribution after direct membrane translocation. We also reveal a hybrid peptide, consisting of D‐α‐aminoxy acids and L‐α‐amino acids, that achieves efficient diffuse distribution in the cytosol, is stable toward serum, and possesses low cytotoxicity, thus making it a possible vector candidate for in vivo applications. Our results confirm that α‐aminoxy acids are useful building blocks when designing novel CPPs possessing favorable properties.
On the Role of Residual Ag in Nanoporous Au Catalysts for CO Oxidation: A Combined Microreactor and TAP Reactor Study
Authors: Wang L. C. , Zhong Y. , Widmann D. , Weissmüller J. , Behm R. J. 
Published: December 2011

AbstractThe influence of residual Ag on the formation of stable adsorbed active oxygen species (oxygen storage capacity, OSC) and its correlation with the activity and stability in the CO oxidation reaction on nanoporous gold (NPG) was investigated by a combination of kinetic and temporal analyses of products (TAP) reactor measurements, comparing four different NPG samples with different Ag contents. The data demonstrated that oxygen can be activated and stored on the NPG catalysts at room temperature. Clearly the surface Ag content influenced both the OSC and activity, with a more qualitative correlation for the fresh catalysts and an approximately linear relationship for the stable catalysts after 1000 min on stream. A strictly linear correlation between catalytic activity and OSC, both before and after the reaction, indicated that the active oxygen detected by the TAP reactor measurements also represents the active oxygen species for the reaction at atmospheric pressure. Consequences for the mechanistic understanding of the CO oxidation reaction on NPG catalysts are discussed.
Donor–Acceptor Ring‐in‐Ring Complexes
Authors: Forgan Ross S. , Wang Cheng , Friedman Douglas C. , Spruell Jason M. , Stern Charlotte L. , Sarjeant Amy A. , Cao Dennis , Stoddart J. Fraser 
Published: December 2011

AbstractThe self‐assembly of three donor–acceptor ring‐in‐ring complexes, prepared from the π‐electron‐deficient tetracationic cyclophane, cyclobis(paraquat‐4,4′‐biphenylene), and three large π‐electron‐rich crown ethers (each 50‐membered rings) containing dioxynaphthalene (DNP) and tetrathiafulvalene (TTF) units in pairs (DNP/DNP, DNP/TTF and TTF/TTF), is reported. 1H NMR spectroscopic analyses are indicative of the formation of 1:1 complexes in CD3CN, whilst the charge‐transfer interactions between the DNP and TTF units of the crown ethers and the tetracationic cyclophane have permitted the measurement of binding constants of up to 4×103 M−1 in CH3CN to be made using UV/Vis spectroscopy. Ring‐in‐ring complexes are proposed as intermediates in the stepwise synthesis of molecular Borromean rings (BRs) comprised of three different rings. With the particular choice of crown ethers, the 1:1 complexes have polyether loops that protrude from the donor–acceptor recognition point above and below the mean plane of the tetracationic cyclophane, which, ideally, could conceivably bind dialkylammonium centers present in a third ring. X‐ray crystallographic analyses of the solid‐state superstructures of two of the three 1:1 complexes reveal, however, the presence of prodigious CH⋅⋅⋅O interactions between the polyether loops of the crown ethers and the rims of the cyclophane, no doubt stabilizing the complexes, but, at the same time, masking their potential recognition sites from further interactions that are essential to the subsequent emergence of the third ring. The solid‐state superstructure of one of the crown ethers binding two dibenzylammonium ions provides some insight into the design requirements for the next generation of these systems; longer polyether loops may be required to allow optimal interactions between all components. It has become clear during a pursuit of the stepwise synthesis of the molecular BRs that, when designing complex mechanically interlocked molecules utilizing multiple recognition sites, the unsullied orthogonality of the recognition motifs is of the utmost importance.
Adsorption–Reduction Behavior of Co(NH3) on Activated Carbon
Authors: Mao Yan‐Peng , Chen Yu , Cheng Jing‐Yi , Zhu Hai‐Song , Long Xiang‐Li , Yuan Wei‐Kang 
Published: December 2011

AbstractA novel method has been put forward to retrofit the wet ammonia desulfurization process to realize the combined removal of sulfur dioxide and nitric oxide by introducing soluble cobalt(II) salt into aqueous ammonia solution. The active constituent of scrubbing NO from the flue gases is the ${\rm Co(NH}_{{\rm 3}} {\rm )}_{{\rm 6}}^{{\rm 2 + }} $ produced by ammonia coordinating with Co2+. The regeneration of ${\rm Co(NH}_{{\rm 3}} {\rm )}_{{\rm 6}}^{{\rm 2 + }} $ can be realized under the catalysis of activated carbon so as to sustain a high NO removal efficiency for a long time. In this paper, the adsorption–reduction behavior of ${\rm Co(NH}_{{\rm 3}} {\rm )}_{{\rm 6}}^{{\rm 3 + }} $ on activated carbon has been researched using scanning electron microscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy. A conclusion can be drawn from the results that cobalt ions in the aqueous solution are adsorbed by activated carbon and most of them are reduced to Co2+ ions, and some of the Co2+ ions are further reduced into metallic cobalt. The results also demonstrate that the functional groups on the surface of carbon take part in this redox reaction. The CH groups on the carbon surface are oxidized into COH, and then some of the hydroxyl groups are further oxidized into carbonyl or carboxyl groups.
Treating Leather Tanning Wastewater with Stone Cutting Solid Waste
Authors: Al‐Jabari Maher , Abualfailat Malek , Shaheen Safa 
Published: December 2011

AbstractThis paper presents a new environmental approach for reducing environmental impacts of two local Palestinian industries: It implements the principle of “treating waste by waste.” The technical feasibility of chromium removal from wastewater in leather making by its treatment with solid waste from stone cutting industry is demonstrated experimentally, and found to be an efficient approach. Nearly full removal of chromium is obtained at optimum operating conditions using sufficient mass of solid waste (limestone) and allowing enough contact time between the two wastes. This study investigated effects of various parameters on the percentage relative decrease in concentration by using ultra violet (UV)/Vis spectrophotometry. Kinetic curves showed that percentage relative decrease in concentration increased with time until approaching a plateau (adsorption capacity). The adsorption capacity increased with increasing limestone to liquid ratio (solid content), until nearly full removal of chromium was obtained when the solid content was 5 g/100 mL or higher. This was accomplished within few days when the particles were settled. The adsorption capacity was pH dependent; adsorption at pH < 5 was obtained, as a finding which was not reported by previous investigators for Cr(III) adsorption using other particles. The percentage removal was nearly doubled at higher pH values (>5). Further research work is proposed to distinguish between the contributions of the two removal mechanisms of precipitation and adsorption.
Cognitive functioning after cancer treatment
Authors: Phillips Kristin M. , Jim Heather S. , Small Brent J. , Laronga Christine , Andrykowski Michael A. , Jacobsen Paul B. 
Published: December 2011

AbstractBACKGROUND:This study examined the influence of prior treatment on the course of cognitive functioning in breast cancer survivors. Changes in cognitive functioning over time were compared in breast cancer survivors treated with chemotherapy plus radiotherapy, breast cancer survivors treated with radiotherapy only, and women with no history of cancer.METHODS:Stage 0‐II breast cancer patients treated with chemotherapy plus radiotherapy (CT group; n = 62) or radiotherapy only (RT group; n = 67) completed neuropsychological assessments 6 months after completing treatment and again 36 months later. Women with no history of cancer (NC group; n = 184) were assessed over a similar interval.RESULTS:A significant group × time effect was found for processing speed (P = .009) that reflected a tendency for the NC group but not the RT and CT groups to improve over time. There was also a significant group effect for executive functioning (P = .006) that reflected the NC group performing better than the CT and RT groups. Additional analyses found the administration of hormonal therapy was not associated with change over time in cognitive performance.CONCLUSIONS:Findings provide limited support for the view that changes in cognitive functioning in cancer survivors are attributable to chemotherapy administration and illustrate the importance of including a radiotherapy comparison group. Future research should seek to examine possible mechanisms that could explain the apparent prolonged impact of both chemotherapy and radiotherapy on cognitive functioning in breast cancer survivors. Cancer 2012;. © 2011 American Cancer Society.