bluuebunny/crossref_metadata_2025 huggingface dataset:
Realization of a Service Robot for Cleaning Spherical Surfaces
Authors: Zhang Houxiang , Zhang Jianwei , Liu Rong , Zong Guanghua
Published: March 2012

There are more and more buildings with complicated shape emerging all over the world. Their walls require constant cleaning which is difficult to realize. In this paper, based on analyzing the characteristics of the working target, a new kind of auto-climbing robot is proposed, which is used for cleaning the spherical surface of the National GrandTheatre in China. The robots' mechanism and unique aspects are presented in detail. A distributed controller based onCAN bus is designed to meet the requirements of controlling the robot. The control system is divided into 6 parts, fiveCAN bus control nodes and a remote controller, which are designed and established based mainly on the P80C592. Finally, the motion function is described in detail. The experimental results confirm the principle described above andthe robot's ability to work on the spherical surface.
Research on a Novel Parallel Engraving Machine and its Key Technologies
Authors: Ling-fu Kong , Shi-hui Zhang
Published: March 2012

In order to compensate the disadvantages of conventional engraving machine and exert the advantages of parallel mechanism, a novel parallel engraving machine is presented and some key technologies are studied in this paper. Mechanism performances are analyzed in terms of the first and the second order influence coefficient matrix firstly. So the sizes of mechanism, which are better for all the performance indices of both kinematics and dynamics, can be confirmed and the restriction due to considering only the first order influence coefficient matrix in the past is broken through. Therefore, the theory basis for designing the mechanism size of novel engraving machine with better performances is provided. In addition, method for tool path planning and control technology for engraving force is also studied in the paper. The proposed algorithm for tool path planning on curved surface can be applied to arbitrary spacial curved surface in theory, control technology for engraving force based on fuzzy neural network(FNN) has well adaptability to the changing environment. Research on teleoperation for parallel engraving machine based on B/S architecture resolves the key problems such as control mode, sharing mechanism for multiuser, real-time control for engraving job and real-time transmission for video information. Simulation results further show the feasibility and validity of the proposed methods.
Recursive Backstepping Stabilization of a Wheeled Mobile Robot
Authors: Mnif Faical
Published: March 2012

This research is aimed to the development of a dynamic control to enhance the performance of the existing dynamic controllers for mobile robots. System dynamics of the car-like robot with nonholonomic constraints were employed. A Backstepping approach for the design of discontinuous state feedback controller is used for the design of the controller. It is shown that the origin of the closed loop system can be made stable in the sense of Lyapunov. The control design is made on the basis of a suitable Lyapunov function candidate. The effectiveness of the proposed approach is tested through simulation on a car-like vehicle mobile robot.
The Intelligent Vehicle Coordination of the Cybernetic Transportation System
Authors: Wang Fenghui , Yang Ming , Yang Ruqing
Published: March 2012

Cybernetic Transportation System (CTS) is a new branch of Intelligent Transportation Systems (ITS), which is a solution to the urban transportation problem. The coordination of intelligent vehicles is critical for the operation of the Cybernetic Transportation System. We present a distributed coordination approach for the intelligent vehicles of the Cybernetic Transportation System, which is based on an agent-based framework. Each vehicle agent generates intention independently by considering its and other agents' shared status and intentions in the coordination. Typical coordination scenes, including platoon and overtaking, have been demonstrated in the two-lane, two-way traffic situation and the effectiveness of the proposed coordination approach has been validated.
Revisiting the thermal relaxations of poly(vinyl alcohol)
Authors: Betzabe Gonzalez‐Campos J. , Garcia‐Carvajal Zaira Y. , Prokhorov E. , Luna‐Barcenas J. Gabriel , Mendoza‐Duarte M. E. , Lara‐Romero Javier , del Rio Rosa E. , Sanchez Isaac C.
Published: March 2012

The molecular dynamics of poly(vinyl alcohol) (PVA) were studied by dielectric spectroscopy and dynamic mechanical analysis in the 20–300°C range. The well‐established plasticizing effect of water on the glass‐transition temperature (Tg) of PVA was revisited. Improper water elimination analysis has led to a misinterpretation of thermal relaxations in PVA such that a depressed Tg for wet PVA films (ca. 40°C) has been assigned as a secondary β relaxation in a number of previous studies in the literature. In wet PVA samples, two different Vogel–Fulcher–Tammann behaviors separated by the moisture evaporation region (from 80 to 120°C) are observed in the low‐ (from 20 to 80°C) and high‐ (>120°C) temperature ranges. Previously, these two regions were erroneously assigned to two Arrhenius‐type relaxations. However, once the moisture was properly eliminated, a single non‐Arrhenius α relaxation was clearly observed. X‐ray diffraction analysis revealed that the crystalline volume fraction was almost constant up to 80°C. However, the crystallinity increased approximately 11% when temperature increased to 180°C. A secondary βc relaxation was observed at 140°C and was related to a change in the crystalline volume fraction, as previously reported. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
B‐vitamins for neuroprotection: Narrowing the evidence gap
Authors: Nachum‐Biala Yaarit , Troen Aron M.
Published: March 2012

A compelling and extensive epidemiological literature documents the strong association of inadequate status of folate, vitamin B12, and to a lesser degree vitamin B6, with increased risk of neurodegenerative and cerebrovascular disease. Mildly elevated plasma total homocysteine, which is biochemically related to low status of these B‐vitamins, is similarly associated with increased risk for these conditions. This, together with experimental data showing that experimental B‐vitamin deficiency and/or hyperhomocysteinemia can cause a variety of neurological and vascular deficits in animals, has provided the evidence base and motivation for a growing number of large randomized, double‐blind clinical trials aimed at determining the efficacy and safety of B‐vitamin supplementation for preserving cognitive function in older adults. Despite some encouraging trials showing benefit of B‐vitamins for slowing brain atrophy and cognitive decline, the majority of these studies have not demonstrated that B‐vitamin supplementation has protective or therapeutic cognitive benefit. There are many possible explanations for the inconsistency between the clinical trials and for the discrepancy between their findings and the predictions of the epidemiological evidence. Among these are the possibility of inadequate hypotheses guiding the trials, design limitations of the individual trials, and inherent limitations of nutritional randomized clinical trials. Resolving these issues will be crucial for designing definitive trials and ultimately for guiding nutritional interventions for cognitive protection.
Non‐enzymatic palladium recovery on microbial and synthetic surfaces
Authors: Rotaru Amelia‐Elena , Jiang Wei , Finster Kai , Skrydstrup Troels , Meyer Rikke Louise
Published: March 2012

The use of microorganisms as support for reduction of dissolved Pd(II) to immobilized Pd(0) nanoparticles is an environmentally friendly approach for Pd recovery from waste. To better understand and engineer Pd(0) nanoparticle synthesis, one has to consider the mechanisms by which Pd(II) is reduced on microbial surfaces. Escherichia coli, Shewanella oneidensis, and Pseudomonas putida were used as model organisms in order to elucidate the role of microbial cells in Pd(II) reduction under acidic conditions. Pd(II) was reduced by formate under acidic conditions, and the process occurred substantially faster in the presence of cells as compared to cell‐free controls. We found no difference between native (untreated) and autoclaved cells, and could demonstrate that even a non‐enzymatic protein (bovine serum albumin) stimulated Pd(II) reduction as efficiently as bacterial cells. Amine groups readily interact with Pd(II), and to specifically test their role in surface‐assisted Pd(II) reduction by formate, we replaced bacterial cells with polystyrene microparticles functionalized with amine or carboxyl groups. Amine‐functionalized microparticles had the same effect on Pd(II) reduction as bacterial cells, and the effect could be hampered if the amine groups were blocked by acetylation. The interaction with amine groups was confirmed by infrared spectroscopy on whole cells and amine‐functionalized microparticles. In conclusion, bio‐supported Pd(II) reduction on microbial surfaces is possibly mediated by a non‐enzymatic mechanism. We therefore suggest the use of amine‐rich biomaterials rather than intact cells for Pd bio‐recovery from waste. Biotechnol. Bioeng. 2012; 109:1889–1897. © 2012 Wiley Periodicals, Inc.
Bacterial β‐glucosidase function and metabolic activity depend on soil management in semiarid rainfed agriculture
Authors: Cañizares Rosa , Moreno Beatriz , Benitez Emilio
Published: March 2012

Genomic and transcriptomic approaches were used to gain insights into the relationship between soil management and bacterial‐mediated functions in an olive orchard agroecosystem. Four management practices were assessed in a 30‐year trial in a semiarid Mediterranean region. Transcriptional activity of bacterial 16S rRNA genes increased in noncovered soils, indicating higher microbial maintenance requirements to thrive in less favorable environmental conditions. The 16S rRNA transcript:gene copy ratio confirmed this assumption and pointed toward a much higher constitutive expression from rRNA operons in noncovered soils and to even higher expression levels when spontaneous vegetation was removed chemically. As described for 16S rRNA, potential transcription did not reveal the real transcription of bacterial β‐glucosidase genes, and higher gene expression in noncovered soils plus herbicides was evidenced. Since no relationship between total or soluble organic carbon and bacterial β‐glucosidase transcription was found, the above hypothesis could indicate either that soluble organic carbon is not the main pool of enzyme‐inducing substrates or that constitutive production of bacterial β‐glucosidase enzymes increases as soil conditions worsen.
Three‐Component Coupling of Aldehydes, Amines, and Alkynes Catalyzed by Oxidized Copper Nanoparticles on Titania
Authors: Albaladejo María José , Alonso Francisco , Moglie Yanina , Yus Miguel
Published: March 2012

Copper nanoparticles (mainly as Cu2O) on titania have been shown to catalyze the multicomponent synthesis of propargylamines from aldehydes, amines, and alkynes (A3 coupling) effectively at 70 °C under solvent‐free conditions. Both aromatic and aliphatic aldehydes and alkynes have been combined with secondary amines to provide a wide range of propargylamines in moderate to excellent yields. Two examples of ketone/amine/alkyne (KA2) coupling are also included. The catalyst is easy to prepare, reusable at a low copper loading (0.5 mol‐%), and exhibits higher catalytic activity than some commercially available copper sources. Some mechanistic aspects of the reaction have also been examined, which have unveiled the participation of copper(I) acetylides in a heterogeneous process.
Implementation and validation of video monitoring for wood budgeting in a wandering piedmont river, the Ain River (France)
Authors: MacVicar Bruce , Piégay Hervé
Published: March 2012

The transport of wood in rivers during floods is an important process that underlies differences in habitat and morphology between water courses and regions. Quantitative data are needed to properly address management objectives and balance wood budgets. In this study we use a streamside video camera to detect wood passage and measure quasi‐instantaneous rates of wood transport in the Ain River, France. The objectives are to verify the procedure, describe the relation between wood transport and discharge, and construct and validate a wood budget for the reach upstream of the camera. Verification of the procedure includes tests of detection frequency, wood velocity, and piece size. A log base two transformation is proposed to classify wood by piece length. It was found that a wood transport threshold occurs at approximately two thirds of the bankfull discharge. Wood transport follows a positive linear relation with discharge up to the bankfull discharge but is both more variable and less sensitive to discharge when the floodplain is inundated. Transport rates are approximately four times higher on the rising limb of the hydrograph than on the falling limb. Wood transport estimates from a three‐stage rating curve are two to 10 times higher than those from a wood budget using local and aerial surveys of upstream dynamics. Future work should address uncertainties related to wood diameter measurements, sampling length and frequency, and antecedent floods. Copyright © 2012 John Wiley & Sons, Ltd.
Generation and evolution of inelastic microstructures ‐ an overview
Authors: Hackl Klaus , Hoppe Ulrich , Kochmann Dennis M.
Published: March 2012

In this paper we give an overview on the modeling of inelastic microstructures using variational methods. We start by discussing the underlying variational principles for inelastic materials, derive evolution equations for internal variables, and introduce the concept of condensed energy. As a mathematical prerequisite we review the variational calculus of nonconvex potentials and the notion of relaxation. We use these instruments in order to study the initiation of plastic microstructures. Here we focus on a model of single‐slip crystal plasticity. Afterwards we move on to model the evolution of microstructures. We introduce the concept of essential microstructures and the corresponding relaxed energies and dissipation potentials, and derive evolution equations for microstructure parameters. We then present a numerical scheme by means of which the microstructure development can be computed, and show numerical results for particular examples (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
S -adenosyl methionine regulates ubiquitin-conjugating enzyme 9 protein expression and sumoylation in murine liver and human cancers
Authors: Tomasi Maria Lauda , Tomasi Ivan , Ramani Komal , Pascale Rosa Maria , Xu Jun , Giordano Pasquale , Mato José M. , Lu Shelly C.
Published: March 2012

Ubiquitin-conjugating enzyme 9 (Ubc9) is required for sumoylation and is overexpressed in several malignancies, but its expression in hepatocellular carcinoma (HCC) is unknown. Hepatic

S
-adenosyl methionine (SAMe) levels decrease in methionine adenosyltransferase 1A (
Mat1a
) knockout (KO) mice, which develop HCC, and in ethanol-fed mice. We examined the regulation of Ubc9 by SAMe in murine liver and human HCC, breast, and colon carcinoma cell lines and specimens. Real-time polymerase chain reaction and western blotting measured gene and protein expression, respectively. Immunoprecipitation followed by western blotting examined protein-protein interactions. Ubc9 expression increased in HCC and when hepatic SAMe levels decreased. SAMe treatment in

Mat1a

KO mice reduced Ubc9 protein, but not messenger RNA (mRNA) levels, and lowered sumoylation. Similarly, treatment of liver cancer cell lines HepG2 and Huh7, colon cancer cell line RKO, and breast cancer cell line MCF-7 with SAMe or its metabolite 5′-methylthioadenosine (MTA) reduced only Ubc9 protein level. Ubc9 posttranslational regulation is unknown. Ubc9 sequence predicted a possible phosphorylation site by cell division cycle 2 (Cdc2), which directly phosphorylated recombinant Ubc9.

Mat1a

KO mice had higher phosphorylated (phospho)-Ubc9 levels, which normalized after SAMe treatment. SAMe and MTA treatment lowered Cdc2 mRNA and protein levels, as well as phospho-Ubc9 and protein sumoylation in liver, colon, and breast cancer cells. Serine 71 of Ubc9 was required for phosphorylation, interaction with Cdc2, and protein stability. Cdc2, Ubc9, and phospho-Ubc9 levels increased in human liver, breast, and colon cancers.

Conclusion:

Cdc2 expression is increased and Ubc9 is hyperphosphorylated in several cancers, and this represents a novel mechanism to maintain high Ubc9 protein expression that can be inhibited by SAMe and MTA.
Beneficial effect of plasma exchange in the treatment of toxic epidermal necrolysis: A series of four cases
Authors: Košt́ál Milan , Bláha Milan , Lánská Miriam , Košt́álová Marie , Bláha Vladimír , Štepánová Eva , Malý Jaroslav
Published: March 2012

Introduction: Toxic epidermal necrolysis (TEN) is a rare, life‐threatening disease with a high mortality rate that is linked to drug toxicity. There is a lack of data about the underlying pathophysiologic mechanisms and treatment options. The only widely accepted treatment of TEN is withdrawal of the offending drug followed by supportive care. The potential roles of corticosteroids, intravenous immunoglobulin (IVIG) and plasmapheresis (TPE) remain controversial. Aims: We present four patients with severe TEN (all with >80% involvement of body surface) who were treated with TPE following unsuccessful treatment with corticosteroids/IVIG. Methods: TPE was performed using a COBE Spectra blood cell separator. ACD‐A was used as anticoagulant fluid and the target‐washed plasma volume was one body volume. Plasma was replaced by a 5% solution of human albumin + Ringer's lactate. Results: The mean number of TPE sessions was 5.25 ± 2.22 (range 3–8). Drugs were implicated as an etiologic agent in each case. TPE led to prompt improvement of acute condition and general health as well as halting of disease progression. Additionally, the restoration of the epithelium began in all four patients. Conclusion: Plasmapheresis should be considered as an alternative treatment modality for patients with the most severe form of TEN if initial treatment with other agents, including corticosteroids and/or IVIG, fails. Drugs were suspected to be the cause of TEN in all four cases. J. Clin. Apheresis, 2012. © 2012 Wiley Periodicals, Inc.
Efficacy of in‐office bleaching techniques combined with the application of a casein phosphopeptide‐amorphous calcium phosphate paste at different moments and its influence on enamel surface properties
Authors: Gama Cunha Ana Gabriela , Meira De Vasconcelos Adriana Alcantara , Dutra Borges Boniek Castillo , De Oliveira Vitoriano Jussier , Alves‐Junior Clodomiro , Machado Claudia Tavares , Dos Santos Alex Jose Souza
Published: March 2012

OBJECTIVES: The aim of this in vitro study was to investigate the efficacy of in‐office bleaching technique combined with the application of a casein phosphopeptide‐amorphous calcium phosphate (CPP‐ACP) paste (MI Paste–MI) at different moments and its influence on enamel surface properties. METHODS: Eighty bovine dental crowns were randomly allocated into eight groups (n = 10), and bleached with either 35% hydrogen peroxide (HP) or 37% carbamide peroxide (CP). Four different protocols of application of MI were considered: without MI, MI applied before bleaching, MI applied after bleaching, and MI applied both before and after bleaching. Bleaching effectiveness was measured by the VITA EasyShade spectrophotometer utilizing the CIEL*a*b* system (ΔE, ΔL*, Δa*, and Δb*). Color readings were measured at baseline, 7, 14, and 21 days. Hardness and roughness were measured at baseline (T0) and immediately after bleaching (T14). Data were subjected to the two‐way ANOVA for repeated measurements and Tukey's test at 5%. RESULTS: HP groups achieved the greatest color change. The application of a CPP‐ACP paste did not reduce the efficacy of bleaching peroxides. Samples bleached with CP showed decreased hardness at T14. Samples bleached with HP that received the application of MI before and before/after bleaching did not present hardness decrease at T14. Samples bleached with peroxides only and received MI after bleaching showed increased roughness at T14. CONCLUSIONS: The use of CPP‐ACP was able to prevent negative changes in roughness and hardness of bovine enamel when associated to hydrogen peroxide, and might be applied before/after the bleaching protocol. Microsc. Res. Tech. 75:1019–1025, 2012. © 2012 Wiley Periodicals, Inc.
Clean and reproducible SERS substrates for high sensitive detection by solid phase synthesis and fabrication of Ag‐coated Fe3O4 microspheres
Authors: Yang Liangbao , Bao Zhiyong , Wu Yucheng , Liu Jinhuai
Published: March 2012

The solid‐phase synthesis of Ag‐coated Fe3O4 microsphere was elaborated under argon atmosphere. This straightforward process utilized neither reducing agents nor electric current and involved the dry mixing of a precursor of CH3COOAg with Fe3O4 microspheres followed by heating in an inert atmosphere. Ag nanoparticles with diameters of 30–50 nm were well‐decorated on the surfaces of Fe3O4 microspheres. The as‐synthesized Ag‐coated Fe3O4 microspheres were assembled into a surface‐enhanced Raman scattering (SERS) substrate holding clean and reproducible properties under an externally exerted magnetic force. Using these nanoprobes, analyte molecules can be easily captured, magnetically concentrated, and analyzed by SERS. This clean SERS substrate was used to detect 4‐aminothiophenol, even at a concentration as low as1.0 × 10–12 M. In particular, the Ag‐coated Fe3O4 microspheres, acting as reproducible SERS substrates, were applied to detect methyl‐parathion and 4‐mercaptopyridine. Strong SERS signals were obtained with the analytes at a concentration of 1.0 × 10–6 M. The unique, clean, and reproducible properties indicate a new route in eliminating the single‐use problem of traditional SERS substrates and show promising applications for detecting other organic pollutants. Similarly, this work may provide a new model system to a series of metal–Fe3O4 decorating reactions for a reproducible utilization. Copyright © 2012 John Wiley & Sons, Ltd.
A subspace shift technique for nonsymmetric algebraic Riccati equations associated with an M‐matrix
Authors: Iannazzo Bruno , Poloni Federico
Published: March 2012

The worst situation in computing the minimal nonnegative solution of a nonsymmetric algebraic Riccati equation associated with an M‐matrix occurs when the corresponding linearizing matrix has two very small eigenvalues, one with positive and one with negative real part. When both eigenvalues are exactly zero, the problem is called critical or null recurrent. Although in this case the problem is ill‐conditioned and the convergence of the algorithms based on matrix iterations is slow, there exist some techniques to remove the singularity and transform the problem to a well‐behaved one. Ill‐conditioning and slow convergence appear also in close‐to‐critical problems, but when none of the eigenvalues is exactly zero, the techniques used for the critical case cannot be applied. In this paper, we introduce a new method to accelerate the convergence properties of the iterations also in close‐to‐critical cases, by working on the invariant subspace associated with the problematic eigenvalues as a whole. We present numerical experiments that confirm the efficiency of the new method.Copyright © 2012 John Wiley & Sons, Ltd.
A DFT study on the standard electrode potentials of 2‐substituted imidazoles
Authors: Tugsuz Tugba
Published: March 2012

Extensive density functional theory, calculations, with optimization of geometries and estimation of substituent effects, have been performed to investigate the electrode potentials of dimer and protonated cation structures of 2‐substituted imidazoles. The gas phase geometries of dimer, anion, protonated cation, and neutral structures of 2‐substituted imidazoles have been optimized using Boese‐Martin for kinetics (BMK) and the Minnesota 2005 (M05) hybrid functionals combined with the valence triple‐ζ quality with polarization function (TZVP) basis set. The geometries in the presence of acetonitrile solvent have been optimized using the conductor‐like polarizable continuum model model of solvation at the same levels of theory. Frequency calculations have been performed for all the structures and none of them is found to exhibit any imaginary frequency. NH‐‐‐H infrared harmonic frequencies have been calculated and compared with available experimental data. The substituent effects on the electrode potentials of imidazole have been investigated as electron donating CH3, OH, NH2, OCH3 and electron withdrawing NO2, Cl, F, Br groups, which are bonded to the second numbered carbon atom of the imidazole molecule. It has been found that electron donating substituents show more negative electrode potentials, whereas electron withdrawing substituents have the opposite effect. © 2012 Wiley Periodicals, Inc.
Estimation and variable selection via frailty models with penalized likelihood
Authors: Androulakis E. , Koukouvinos C. , Vonta F.
Published: March 2012

The penalized likelihood methodology has been consistently demonstrated to be an attractive shrinkage and selection method. It does not only automatically and consistently select the important variables but also produces estimators that are as efficient as the oracle estimator. In this paper, we apply this approach to a general likelihood function for data organized in clusters, which corresponds to a class of frailty models, which includes the Cox model and the Gamma frailty model as special cases. Our aim was to provide practitioners in the medical or reliability field with options other than the Gamma frailty model, which has been extensively studied because of its mathematical convenience. We illustrate the penalized likelihood methodology for frailty models through simulations and real data. Copyright © 2012 John Wiley & Sons, Ltd.
Naloxone can act as an analgesic agent without measurable chronic side effects in mice with a mutant mu‐opioid receptor expressed in different sites of pain pathway
Authors: Chou Shu‐Husan , Kao Jen‐Hsin , Tao Pao‐Luh , Law Ping‐Yee , Loh Horace H.
Published: March 2012

Midbrain periaqueductal gray (PAG) and spinal cord dorsal horn are major action sites of opioid analgesics in the pain pathway. Our previous study has shown that opioid antagonists activate MORS196A‐CSTA (a mutant of mu‐opioid receptor) as full agonists in vitro cell models and naloxone showed antinociceptive effects after the expression of MORS196A‐CSTA in the spinal cord in mice. The purpose of this study is to investigate the site‐directed antinociceptive effects of naloxone in mice injected with dsAAV‐MORS196A‐CSTA‐EGFP at spinal cord or at periaqueductal gray. MORS196A‐CSTA‐EGFP was administered to ICR mice using dsAAV as vector. We measured MORS196A‐CSTA‐EGFP expression by detecting the EGFP visualization with a fluorescence microscope. The antinociceptive effect of naloxone was determined by tail‐flick test and hot plate test. Drug rewarding effect was evaluated by the conditioned place preference test. Naloxone (10 mg/kg, s.c.) elicited both supraspinal and spinal antinociceptive responses in mice injected with the virus at PAG while only spinal antinociceptive response was observed in mice injected with virus at dorsal horn region. Chronic naloxone treatment did not induce physical dependence or rewarding effect in mice injected with MORS196A‐CSTA‐EGFP in spinal cord or PAG. These data suggest that the observed naloxone‐induced antinociceptive response is the consequence of the local expression of MORS196A‐CSTA at specific sites of pain pathway. Injection of such MOR mutant and the systemic administration of naloxone can be a new strategy in the management of chronic pain without the various side effects associated with the use of morphine. Synapse, 2012. © 2012 Wiley Periodicals, Inc.
Optimization of culture medium composition for manganese peroxidase and tyrosinase production during Reactive Black 5 decolourization by the yeast Trichosporon akiyoshidainum
Authors: Martorell María M , Pajot Hipólito F. , Rovati José I. , Figueroa Lucía I. C.
Published: March 2012

Decolourization and degradation of the diazo dye Reactive Black 5 was carried out by the yeast Trichosporon akiyoshidainum. A nine‐factor Plackett–Burman design was employed for the study and optimization of the decolourization process and production of manganese peroxidase (MnP) and tyrosinase activities. In the present study, 26 individual experiments were conducted and three responses were evaluated. Raising yeast extract concentration significantly enhanced decolourization and MnP production. Carbon and nitrogen sources, glucose and (NH4)2SO4, showed no significant effect on any response over the concentration range tested. Other culture medium components, such as CaCl2 or MgSO4, could be excluded from the medium formula, as they had no effect on the evaluated responses. Metal ions (Fe, Cu and Mn) showed different effects on decolourization and enzymatic activities. Addition of copper significantly enhanced MnP activity and decreased dye decolourization. On the contrary, iron had a positive effect on decolourization and no effect on enzyme production. Oddly, increasing manganese concentration had a positive effect on tyrosinase production without affecting decolourization or MnP activity. These results strongly suggest that dye decolourization should be regarded as a complex multi‐enzymatic process, where optimal medium composition should arise as a compromise between those optimal for each implied enzyme production. Copyright © 2012 John Wiley & Sons, Ltd.
The presence of heterospecific males causes an Allee effect
Authors: Kyogoku Daisuke , Nishida Takayoshi
Published: March 2012

The Allee effect is a positive causal relationship between any component of fitness and population density or size. Allee effects strongly affect the persistence of small or sparse populations. Predicting Allee effects remains a challenge, possibly because not all causal mechanisms are known. We hypothesized that reproductive interference (an interspecific reproductive interaction that reduces the fitness of the species involved) can generate an Allee effect. If the density of the interfering species is constant, an increase in the population of the species receiving interference may dilute the per capita effect of reproductive interference and may generate an Allee effect. To test this hypothesis, we examined the effect of heterospecific males on the relationship between per capita fecundity and conspecific density in Callosobruchus chinensis and C. maculatus. Of the two species, only C. maculatus females suffer reproductive interference from heterospecific males. Only C. maculatus, the species susceptible to reproductive interference, demonstrated an Allee effect, and only when heterospecific males were present. In contrast, C. chinensis, the species not susceptible to reproductive interference, demonstrated no Allee effect regardless of the presence of heterospecific males. Our results show that reproductive interference in fact generated an Allee effect, suggesting the potential importance of interspecific sexual interactions especially in small or sparse populations, even in the absence of a shared resource. It may be possible to predict Allee effects produced by this mechanism a priori by testing reproductive interference between closely related species.
Tracing sources and pathways of dissolved nitrate in forest and river ecosystems using high‐resolution isotopic techniques: a review
Authors: Ohte Nobuhito
Published: March 2012

Nitrogen inputs into stream and river ecosystems, and the factors influencing those inputs, are important for various ecological and environmental concerns. Reliable information on where and how nitrogen compounds flow into aquatic ecosystems is indispensable to understanding the nutrient status of these ecosystems. Such information should include the biogeochemical mechanisms and hydrological controls of nutrient leaching into rivers from terrestrial systems such as forests, agricultural fields, and urbanized areas. Advancements in stable isotopomer measurements over the past two decades have expanded the variety of target substances and the precision with which they can be investigated. The high‐throughput microbial denitrifier method allows for simultaneous measurement of nitrogen and oxygen isotope ratios and can provide high‐resolution spatiotemporal information on both nitrate sources and biogeochemical processes. Although advanced techniques of stable isotope analysis have been used extensively to detect sources and estimate the relative contributions of multi‐source systems in various rivers, there are still new horizons in investigating nitrogen transformations. For example, stable isotopes of oxygen (18O and 17O) occurring in nitrate due to atmospheric deposition can be used as natural tracers for evaluating internal nitrogen cycling; these isotopes are distinct from the oxygen within microbially generated nitrate in soils and water bodies. Another future challenge is improved use of nitrous oxide isotopomers in evaluating the relative contributions of nitrification and denitrification. Such analysis could provide insight into the nitrogen transformation that occurs under redox conditions at the boundary between terrestrial and aquatic systems, where nitrification and denitrification often occur simultaneously in soil and aquatic environments.
Clusterin is a specific stabilizer and liberator of extracellular cathepsin K
Authors: Novinec Marko , Lenarčič Brigita , Baici Antonio
Published: March 2012

The cysteine peptidase cathepsin K is a major player in extracellular proteolysis. Here we describe the identification of the multifunctional extracellular chaperone clusterin as a cathepsin K‐binding protein. Clusterin increases the stability of cathepsin K in dilute solution and in the presence of high protein concentration. It does not alter the activity of the enzyme but acts as a liberator by preventing substrate inhibition. Kinetic measurements show that clusterin binds cathepsin K with high affinity (K
d
= 0.5–0.6 nM). Altogether these results provide novel insights into the mechanisms involved in the fine‐tuning of cysteine cathepsin activity in the extracellular space.
SnoN in regulation of embryonic development and tissue morphogenesis
Authors: Zhu Qingwei , Luo Kunxin
Published: March 2012

SnoN (Ski‐novel protein) plays an important role in embryonic development, tumorigenesis and aging. Past studies largely focused on its roles in tumorigenesis. Recent studies of its expression patterns and functions in mouse models and mammalian cells have revealed that SnoN interacts with multiple signaling molecules at different cellular levels to modulate the activities of several signaling pathways in a tissue context and developmental stage dependent manner. These studies suggest that SnoN may have broad functions in the embryonic development and tissue morphogenesis.
The customer consequences of returns in online retailing: An empirical analysis
Authors: Griffis Stanley E. , Rao Shashank , Goldsby Thomas J. , Niranjan Tarikere T.
Published: March 2012

Pressure continues to build on the operations management function to facilitate system and firm level benefits. In the online marketplace, one area of growing interest is that of product returns. Though commonly viewed as a cost center from an operations perspective, operations’ actions have the potential to strongly influence future customer buying behavior in several ways. Using an archival database of actual purchase and returns history provided by a moderately sized online retailer, this study examines the relationship between a customer's experience of product returns, and subsequent shopping behavior. Employing transaction cost, consumer risk, and procedural justice theories, we demonstrate that the returns management process, rather than being regarded as an afterthought to the production and deployment of goods, can significantly and positively influence repurchase behavior. Additionally, we provide evidence that certain customers should be considered for prioritization in the returns process. We suggest ways through which operations managers can take care in discharging their responsibilities in this area – to make returns processing more than simply a “necessary cost of doing business” rather, using it to their advantage in engendering repeat and increased purchase behavior.
Christendom Witnesses to the Martyrs: Modulations of theActa Martyrumin Prudentius'Peristephanon, vi
Authors: BILBY MARK GLEN
Published: March 2012

In hymn vi of hisPeristephanon, Prudentius dramatically reworks the plot of thePassio Fructuosi. The poet turns the perpetrators from well-known and dutiful representatives of a transient empire into despicable caricatures of evil and vice, transforms the martyred bishop from a caring pastor into a heroic leader of heroes, re-narrates the roles of Christian family members as anonymous martyr-cult devotees, and shifts the focus from the martyred bishop as a local, beloved model of imitation and encouragement during a time of persecution to the three martyrs together as co-equal objects of worship and patrons and saviours of their region and devotees.
Development and application of a delayed-release anthelmintic intra-ruminal bolus system for experimental manipulation of nematode worm burdens
Authors: CARLSSON ANJA M. , WILSON KENNETH , IRVINE R. JUSTIN
Published: March 2012

In order to quantify the impact of parasites on host population dynamics, experimental manipulations that perturb the parasite-host relationship are needed but, logistically, this is difficult for wild hosts. Here, we describe the use of a delayed-release anthelmintic delivery system that can be administered when the hosts can be captured and its activity delayed until a more appropriate period in the host-parasite cycle. Our model system is Svalbard reindeer infected with a nematode parasite,Marshallagia marshalli, which appears to accumulate during the Arctic winter. To determine the extent to which this occurs and the effect on host fitness, reindeer need to be treated with anthelmintics in late autumn but they can only be caught and handled in April. To solve this problem, we devised an intra-ruminal capsule that releases the anthelmintic from up to 6 months after being administered. The capsule was trialed in cannulated sheep and red deer to determine optimum capsule orifice size and release rates. Capsules were estimated to release placebo for 100–153 days followed by abamectin for 22–34 days. To test the efficacy of treatment in reindeer, capsules were administered in April and retrieved in October. All capsules had fully released the anthelmintic and treated reindeer had significantly lower worm burdens than controls. Thus, success of this system allows repeated treatment over several years to test the effect of winter parasitism on host fitness.
Atomic structure and magnetic properties of Fe1–xCox alloys
Authors: Cuong Nguyen Manh , Zhao Xin , Ji Min , Wang Cai-Zhuang , Harmon Bruce , Ho Kai-Ming
Published: March 2012

Using genetic algorithm with first-principle calculations, we searched for low-energy crystal structures of Fe1−xCox alloys. We found that Fe1−xCox alloys are highly configurationally degenerate with many additional off-stoichiometric stable structures to the well-known B2 structure. The average magnetic moment of Fe atom increases with concentration of Co in the alloy, while that of Co atom is almost constant, which are consistent with experiments and earlier studies. The magnetic moment of Fe atom is strongly dependent on the number of Co nearest neighbor and it increases with this number.
Thermal behavior of superparamagnetic cobalt nanodots explored by anisotropic magnetic molecular dynamics simulations
Authors: Beaujouan David , Thibaudeau Pascal , Barreteau Cyrille
Published: March 2012

A comparison between atomistic spin dynamics and magnetic molecular dynamics is performed to discuss the influence of various forms of the magnetic anisotropy energy, to reproduce the thermal behavior of superparamagnetic cobalt nanodots. Both classical spins and lattice vibrations are, for the first time, treated simultaneously to explore magnetic thermal effects.
Observation of gate-controlled spin―orbit interaction using a ferromagnetic detector
Authors: Park Youn Ho , Cheol Jang Hyun , Koo Hyun Cheol , Kim Hyung-jun , Chang Joonyeon , Han Suk Hee , Choi Heon-Jin
Published: March 2012

From the Shubnikov-de Haas oscillation, estimation of the spin―orbit interaction parameter is possible only for very low temperature. An alternative method available for much wider temperature range is utilizing the ferromagnetic electrode which contacts the quantum well channel and reads the Fermi level of spin-up and -down subbands. The amount of spin-subband shift is controlled by a gate electric field and finally the spin―orbit interaction induced by Rashba effect is obtained near room temperature. At T = 150 K, a gate voltage shifts the spin subband potential and changes the spin―orbit interaction parameter by 23%.
Influence of magnetic material composition of Fe100−xBx coated tip on the spatial resolution of magnetic force microscopy
Authors: Ohtake Mitsuru , Soneta Kazuki , Futamoto Masaaki
Published: March 2012

Magnetic force microscope (MFM) tips are prepared by coating Si tips of 3 nm radius with 20-nm-thick Fe100−xBx (x = 0, 8, 18, and 34 at. %) alloys. As the B composition increases, the wettability of Fe-B alloy material to Si surface increases and a sharper and smoother MFM tip is obtained. The remanent magnetization of Fe-B alloy material decreases with increasing the B composition, which degrades the MFM signal detection sensitivity. The MFM resolution is influenced by both the tip sharpness and the remanent magnetization of coated Fe-B alloy material. Resolutions of 10.2, 9.2, 7.3, and 9.3 nm are obtained with tips coated with Fe, Fe92B8, Fe82B18, and Fe66B34 materials, respectively. Magnetic bits of 14.9 nm in length of a perpendicular magnetic medium recorded at 1700 kfci are distinguishable in the MFM image observed by using an Fe82B18-alloy coated tip. Fe-B coated tips are suitable to observe the magnetization structures of future high-density recording media.
A biodetection method using magnetic particles and micro traps
Authors: Li Fuquan , Giouroudi Ioanna , Kosel Jürgen
Published: March 2012

The general working principle of magnetoresistive sensors for biological applications is to specifically attach bioanalytesto magnetic particles and then detect the particles that are immobilized on the sensor surface. The immobilization of the particles on the sensor surface commonly uses biomolecular interactions, e.g., antigen-antibody. Thus, the sensor surface needs to be functionalized via biological treatments in order to capture certain bioanalytes. In the presented work, a new method is proposed, which does not rely on functionalization of the sensor surface. Current carrying microstructures in combination with mechanical micro traps are used to immobilize magnetic particles. Analyte detection is based on the difference in size between bare magnetic particles and particles with analyte attached, which causes a different number of particles to be captured in the micro traps.
Magnetic properties of antiferromagnetically coupled antidots of Co/Pd multilayers
Authors: Piramanayagam S. N. , Ranjbar M. , Tan H. K. , Allen Poh W. C. , Sbiaa R. , Chong T. C.
Published: March 2012

Antidots of Co/Pd multilayers with 3-bilayers [(Co/Pd)x3] that were antiferromagnetically coupled(AFC) to (Co/Pd)x10 were fabricated and their magnetic properties were investigated. The thickness of Co in (Co/Pd)x3 was varied from 0.4 to 0.8 nm. Samples with a Co thickness of 0.8 nm in the bilayer showed a perpendicular magnetic anisotropy (PMA) when antiferromagnetically coupled to (Co/Pd)x10. On the other hand, the magnetization direction of single Co/Pd multilayers with thick Co (0.8 nm) as a reference structure (without AFC) was observed to be in plane, indicating that the PMA in (Co/Pd)x3 films with thicker Co is due to the antiferromagnetic coupling. We also carried out a systematic study on this set of thin films patterned in antidot array fabricated using nanoimprint lithography. It was found that the AFC is helpful to induce a perpendicular magnetic anisotropy in both thin film and antidot form. Such a result is interesting both from a fundamental viewpoint and also from their potential applications in spintronics devices and patterned magnetic medium.
High magnetoelectric tuning effect in a polymer-based magnetostrictive-piezoelectric laminate under resonance drive
Authors: Duan Yuan-Feng , Ming Leung Chung , Zhang Shengyao , Zhang Long , Wing Or Siu
Published: March 2012

A polymer-based magnetoelectric (ME) laminate was fabricated by sandwiching one layer of thickness-polarized, length-stretched polyvinylidene fluoride (PVDF) piezoelectric polymer between two layers of length-magnetized, epoxy-bonded Tb0.3Dy0.7Fe1.92 (Terfenol-D) pseudo-1–3 magnetostrictive particulate composite in the thickness direction, and its resonance ME effect was investigated, both experimentally and theoretically, as a function of magnetic bias field (HBias). The laminate showed a high ME voltage coefficient (αV) of 233 mV/Oe at the fundamental resonance frequency (fr) of 60.6 kHz under a relatively low HBias of 0.6 kOe. By controlling HBias in the range of 0.02–1.5 kOe, nonlinear tunabilities as high as 1382 and 8.6% were achieved for αV and fr, respectively, as a result of the reduced eddy-current losses and enhanced non-180° domain-wall motion-induced negative-ΔE effect in the Terfenol-D composite layers as well as the increased compliance contribution from the PVDF polymer layer to allow the motion of non-180° domain walls in the Terfenol-D composite layers. This improved resonance ME tuning effect, together with the durable and tailorable natures, makes the laminate great promise for developing into tunable ME devices.
First order reversal curve studies of permanent magnets
Authors: Schrefl Thomas , Shoji Tetsuya , Winklhofer Michael , Oezelt Harald , Yano Masao , Zimanyi Gergely
Published: March 2012

First order reversal curve (FORC) diagrams are a useful tool to analyze the magnetization processes in magnetic materials. FORC diagrams are computed from measured first order reversal curves on sintered Nd2Fe14B magnets. It is shown that the FORC diagram simplifies if the first order reversal curves a desheared using the macroscopic demagnetizing field given by the geometry of the sample. Furthermore the resulting FORC diagram is almost identical to the FORC diagram measured for a thin platelet of the same material. This opens the possibility to compare experimental FORC diagrams with FORC diagrams computed by micromagnetic simulations.
Investigation of superlattices based on ferromagnetic semiconductor GaMnAs by planar Hall effect
Authors: Chung Sunjae , Lee Sangyeop , Lee Hakjoon , Yoo Taehee , Lee Sanghoon , Liu X. , Furdyna J. K.
Published: March 2012

Two ferromagnetic semiconductor GaMnAs-based superlattices (SLs) were investigated by measuring the planar Hall effect (PHE) with the external magnetic field applied in the plane of the sample. The two GaMnAs/GaAs SLs differed only by the Be doping of the nonmagnetic GaAs spacer layers. Both SLs showed a typical two-step transition behavior in PHE field scans at 4.0 K, essentially the same as that normally observed on single GaMnAs ferromagnetic layers with two in-plane magnetic easy axes. As the temperature increased to 30 K, the behaviors of the PHE changed differently in the two SL samples. The PHE in the undoped SL can be described simply by the temperature dependence of the magnetic anisotropy within the film plane of a GaMnAs film. However, the Be-doped SL revealed a completely different behavior, showing a transition of magnetization with a negative coercive field. The observation of this feature in a ferromagnetic multilayer indicates the presence of spontaneous anti-parallel interlayer exchange coupling between the GaMnAs magnetic layers.