bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion motion in the current sheet with sheared magnetic field – Part 1: Quasi-adiabatic theory
Authors: Artemyev A. V. , Neishtadt A. I. , Zelenyi L. M.
Published: February 2013

Abstract. We present a theory of trapped ion motion in the magnetotail current sheet with a constant dawn–dusk component of the magnetic field. Particle trajectories are described analytically using the quasi-adiabatic invariant corresponding to averaging of fast oscillations around the tangential component of the magnetic field. We consider particle dynamics in the quasi-adiabatic approximation and demonstrate that the principal role is played by large (so called geometrical) jumps of the quasi-adiabatic invariant. These jumps appear due to the current sheet asymmetry related to the presence of the dawn–dusk magnetic field. The analytical description is compared with results of numerical integration. We show that there are four possible regimes of particle motion. Each regime is characterized by certain ranges of values of the dawn–dusk magnetic field and particle energy. We find the critical value of the dawn–dusk magnetic field, where jumps of the quasi-adiabatic invariant vanish.
Effects of Amyloid Beta Peptide on Neurovascular Cells
Authors: Askarova Sholpan , Tsoy Andrey , Shalakhmetova Tamara , Lee James C-M
Published: February 2013

Alzheimer’s disease (AD) is a chronic neurodegenerative disorder, which is characterized by the accumulation of amyloid plaques and neurofibrillary tangles in specific regions of the brain, accompanied by impairment of the neurons, and progressive deterioration of cognition and memory of affected individuals. Although the cause and progression of AD are still not well understood, the amyloid hypothesis is dominant and widely accepted. According to this hypothesis, an increased deposition of amyloid-β peptide (Aβ) in the brain is the main cause of the AD’s onset and progression. There is increasing body of evidence that blood-brain barrier (BBB) dysfunction plays an important role in the development of AD, and may even precede neuron degeneration in AD brain. In the early stage of AD, microvasculature deficiencies, inflammatory reactions, surrounding the cerebral vasculature and endothelial dysfunctions are commonly observed. Continuous neurovascular degeneration and accumulation of Aβ on blood vessels resulting in cerebral amyloid angiopathy is associated with further progression of the disease and cognitive decline. However, little is known about molecular mechanisms that underlie Aβ induced damage of neurovascular cells. In this regards, this review is aimed to address how Aβ impacts the cerebral endothelium.  Understanding the cellular pathways triggered by Aβ leading to alterations in cerebral endothelial cells structure and functions would provide insights into the mechanism of BBB dysfunction and inflammatory processes in Alzheimer’s, and may offer new approaches for prevention and treatment strategies for AD.
A meta‐analysis of the relationship of the Parkin p.Val380Leu polymorphism to Parkinson's disease
Authors: Zhang Yi , Wang Zhen‐Zhen , Sun Hong‐Mei
Published: February 2013

Parkinson's disease (PD) is one of the most common movement disorders. Parkin p.Val380Leu polymorphism (c.1239G > C) has been investigated as a potential genetic hallmark of PD, but studies examining the association between the polymorphism and PD have reported conflicting results. Therefore, we conducted a meta‐analysis to assess the influence of Parkin p.Val380Leu polymorphism on the susceptibility of PD. Computer and hand searches of the literature were conducted using the MEDLINE, EMBASE, Cochrane Library, and China Academic Journals databases to identify studies addressing the association between the Parkin p.Val380Leu polymorphism and PD risk. We performed analyses of study characteristics, heterogeneity, and funnel plot asymmetry in analyses analogous to additive, dominant, recessive, homozygous, and heterozygous genetic models with the odds ratio (OR) as the measure of association. A total of 11 case–control studies involving 2,073 PD cases and 2,131 controls were included. When all 11 studies were pooled into the analysis, the presence of the Leu allele at the Parkin p.Val389Leu polymorphism was associated with decreased risk for PD in three genetic comparison models: OR in additive model: 0.79, 95% confidence interval (CI) = 0.64–0.98, P = 0.029; OR in recessive model: 0.55, 95% CI = 0.35–0.89, P = 0.014; OR in homozygous model: 0.51, 95% CI = 0.32–0.82, P = 0.005. Begg's funnel plot and Egger's test provided visual and statistical evidences for funnel plot symmetry, without evidence presence of publication bias. We conclude that the presence of the Leu allele at the Parkin p.Val380Leu polymorphism is associated decreased risk for PD. © 2013 Wiley Periodicals, Inc.
Nanocomposites of PVC/TiO2 nanorods: Surface tension and mechanical properties before and after UV exposure
Authors: Sokhandani Parvane , Babaluo Ali Akbar , Rezaei Mostafa , Shahrezaei Mehdi , Hasanzadeh Amin , Mehmandoust Shadi Ghaebi , Mehdizadeh Reza
Published: February 2013

In this study, nanocomposites of poly(vinyl chloride) (PVC), using the synthesized titanium dioxide (TiO2) nanorods and commercial nanopowder of titanium dioxide (Degussa P25) were produced by melt blending. The presence of TiO2 nanorods in PVC matrix led to an improvement in mechanical properties of PVC nanocomposites in comparison with unfilled PVC. The photocatalytic degradation behavior of PVC nanocomposites were investigated by measuring their structural change evaluations, surface tension, and mechanical properties before and after UV exposure for 500 h. It was found that mechanical and physical properties of PVC nanocomposites are not reduced significantly after UV exposure in the presence of TiO2 nanorods in comparison with the presence of TiO2 nanoparticles, which can be due to the amorphous structure of the synthesized nanorods. Therefore, it can be concluded that TiO2 nanorods led to an improvement in photostability and mechanical properties of PVC nanocomposites. The interfacial adhesion between TiO2 nanorods and PVC matrix was also investigated. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Class matters in the interview setting? Positionality, situatedness and class
Authors: Mellor Jody , Ingram Nicola , Abrahams Jessie , Beedell Phoebe
Published: February 2013

In this article we argue that despite methodological and analytical advancements in the field of social class research, these developments have not led to a wholehearted discussion about class positionality and situatedness in relation to interviewer–participant dynamics. Despite—or perhaps due to—this methodological gap, there remains an unspoken expectation that class matching, particularly when investigating working‐class groups and practices, is desirable as it engenders empathy on the part of the interviewer which allows for openness on the part of the participant. The team of four interviewers reflect upon their varying experiences of conducting interviews about class with a group of middle‐ and working‐class students at university, arguing that even if class matching between participant and researcher were possible, shared class position does not necessarily equate with similar life experiences, or enable a strong rapport nor a more ethical analysis or understanding of working‐class people's lives. We explore some of the complexities regarding the class‐related positions of the researchers and the participants and consequently advocate that class researchers engage in reflexive practices in order to explore the myriad ways in which the researcher's own class history and current class position both advantage and disadvantage the research process, often in unpredictable ways.
The special optical properties and application of the heterocyclic compound diethyl 6‐anilino‐5H‐2,3‐dithia‐5,7‐diazacyclopenta(cd)indene‐1,4‐dicarboxylate
Authors: Zhao Liangrong , Liu Mingguo , Yan Mingxun , Zhu Yayun , Pan Liangjun , Yang Changying
Published: February 2013

The heterocyclic compound diethyl 6‐anilino‐5H‐2,3‐dithia‐5,7‐diazacyclopenta(cd)indene‐1,4‐dicarboxylate (D1) was found to form highly emissive aggregates in polar solvents, and the aggregate emission can be tuned by the simple addition of water to a dimethylsulfoxide solution. A theoretical study based on Density functional theory (DFT) calculations, shows that intermolecular interactions of D1 with solvent may be potential factors in the fluorescence change. In addition, the phenyl ring in D1 plays an important role because of its response to solvent. In the non‐aggregated state, deprotonation of the N–H of D1 can proceed easily on the addition of base, and the deprotonated compound might interact with Ag+, resulting in a significant change in color and fluorescence quenching, which make it a potential chemosensor for the selective detection of trace amounts of Ag+. Copyright © 2013 John Wiley & Sons, Ltd.
Diastereodivergent Processes in Palladium‐Catalyzed Allylic Alkylation
Authors: Oliveira Maria Teresa , Audisio Davide , Niyomchon Supaporn , Maulide Nuno
Published: February 2013

Dynamic deracemizations are robust strategies wherein a racemate is converted into a single enantiopure product in 100 % yield. A process can be defined as diastereodivergent if multiple diastereomers of the product are possible and if a specific process offers the ability to generate each and every one of them by fine‐tuning the reaction conditions. Palladium‐catalyzed asymmetric allylic alkylation with stabilized nucleophiles is a versatile strategy that can be used to achieve this goal. In this concept, we summarize the advances that have been made in this field. We also introduce and develop the novel concepts of diastereodivergent deracemization and diastereodivergent de‐epimerization.
Bioluminescent Microcapsules: Applications in Activating a Photosensitizer
Authors: Zhao Jie , Fei Jinbo , Gao Liang , Cui Wei , Yang Yang , Wang Anhe , Li Junbai
Published: February 2013

Bioluminescent microcapsules uploading D‐luciferin have been fabricated by using the covalent assembly of firefly luciferase and alginate dialdehyde through a layer‐by‐layer technique. Such assembled microcapsules can produce visible light in the region of 520–680 nm, which can activate the photosensitizers rose bengal (RB) and hypocrellin B (HB) after adding ATP. The microcapsules uploading photosensitizers (RB or HB) have an obvious property to prevent the proliferation of tumor cells in the dark. The assembled bioluminescent microcapsules can be potentially used as photon donors for bioimaging, ATP detection, and photodynamic therapy.
The Combined Role of Catalysis and Solvent Effects on the Biginelli Reaction: Improving Efficiency and Sustainability
Authors: Clark James H. , Macquarrie Duncan J. , Sherwood James
Published: February 2013

The traditional Biginelli reaction is a three‐component condensation between urea, benzaldehyde and an acetoacetate ester to give a dihydropyrimidinone. An investigation into catalytic and solvent effects has returned the conclusion that the diketo–enol tautomerisation equilibrium of the dicarbonyl reactant dictates the yield of the reaction. Whereas the solvent is responsible for the tautomerisation equilibrium position, the catalyst only serves to eliminate kinetic control from the reaction. Generally, to preserve reaction efficiency and improve sustainability, bio‐derivable p‐cymene was found to be a useful solvent. The metal–enolate intermediate that results from the application of a Lewis acidic catalyst often cited as promoting the reaction appears to hinder the reaction. In this instance, a Brønsted acidic solvent can be used to return greater reactivity to the dicarbonyl reagent.
Predicting Diel, Diurnal and Nocturnal Dynamics of Dissolved Oxygen and Chlorophyll‐a Using Regression Models and Neural Networks
Authors: Karakaya Nusret , Evrendilek Fatih , Gungor Kerem , Onal Deniz
Published: February 2013

Human‐induced and natural interruptions with continuous streams of observational data necessitate the development of gap‐filling and prediction strategies towards better understanding, monitoring and management of aquatic systems. This study quantified the efficacy of multiple non‐linear regression (MNLR) versus artificial neural network (ANN) models as well as the temporal partitioning of diurnal versus nocturnal data for the predictions of chlorophyll‐a (chl‐a) and dissolved oxygen (DO) dynamics. The temporal partitioning increased the predictive performances of the best MNLR models of diurnal DO by 45% and nocturnal DO by 4%, relative to the best diel MNLR model of diel DO ($r_{{\rm adj}}^{2} = 68.8\%$). The ANN‐based predictions had a higher predictive power than the MNLR‐based predictions for both chl‐a and DO except for diurnal DO dynamics. The best ANNs based on independent validations were multilayer perceptron (MLP) for diel chl‐a, generalized feedforward (GFF) for diurnal and nocturnal chl‐a, MLP for diel DO, GFF for diurnal DO, and MLP for nocturnal DO.
Clinical Safety, Pharmacokinetics, and Pharmacodynamics of the 11β‐Hydroxysteroid Dehydrogenase Type 1 Inhibitor ABT‐384 in Healthy Volunteers and Elderly Adults
Authors: Liu Wei , Katz David A. , Locke Charles , Daszkowski Dan , Wang Yi , Rieser Matthew J. , Awni Walid , Marek Gerard J. , Dutta Sandeep
Published: February 2013

ABT‐384 is a potent and selective inhibitor of 11β‐hydroxysteroid dehydrogenase type 1 (HSD‐1), the enzyme that regenerates cortisol in several tissues. Two clinical studies of ABT‐384 were undertaken to assess its safety, pharmacokinetics, target engagement, and pharmacologic effects in healthy subjects. Single doses from 1 to 240 mg, and multiple doses from 1 to 100 mg once daily for 7–14 days, were administered to healthy adults. Multiple doses from 10 to 100 mg once daily for 21 days were administered to elderly subjects. A total of 103 subjects received at least 1 dose of ABT‐384. A maximum‐tolerated dose was not defined in either study. The pharmacokinetic profiles of ABT‐384 and its active metabolite support once daily dosing. Analysis of urine cortisol metabolites demonstrated full hepatic HSD‐1 inhibition with regimens from 1 mg daily, and confirmed in vitro target selectivity. Pharmacologic effects included increases of adrenocorticotrophic hormone levels, cortisol production and androgen and estradiol levels. ABT‐384 has a wide therapeutic index relative to full hepatic target engagement which is relevant for indications such as diabetes and metabolic syndrome. Its therapeutic index for other potential indications such as Alzheimer's disease remains to be established.
Native Biomolecules in the Gas Phase? The Case of Green Fluorescent Protein
Authors: Frankevich Vladimir , Barylyuk Konstantin , Chingin Konstantin , Nieckarz Robert , Zenobi Renato
Published: February 2013

Green fluorescent protein (GFP) was ionized by native electrospray ionization and trapped for many seconds in high vacuum, allowing fluorescence emission to be measured as a probe of its biological function, to answer the question whether GFP exists in the native form in the gas phase or not. Although a narrow charge‐state distribution, a collision cross‐section very close to that expected for correctly folded GFP, and a large stability against dissociation all support a near‐native gas‐phase structure, no fluorescence emission was observed. The loss of the native form is attributed to the absence of residual water in the gas phase, which normally stabilizes the para‐hydroxybenzylidene imidazolone chromophore of GFP.
Selective Synthesis of DOPA and DOPA Peptides by Native and Immobilized Tyrosinase in Organic Solvent
Authors: Botta Giorgia , Delfino Michela , Guazzaroni Melissa , Crestini Claudia , Onofri Silvano , Saladino Raffaele
Published: February 2013

3,4‐Dihydroxyphenylalanine (DOPA)‐containing peptides and proteins provide attractive design paradigms for pharmaceutical applications and engineering of synthetic polymers. An efficient and selective route to DOPA peptides by oxidation of L‐tyrosine derivatives with tyrosinase is reported. The efficiency of the procedure was tested by using successively recycled tyrosinase immobilized on Eupergit®C250L and coated with polyelectrolytes by the layer‐by‐layer method.
Efficient Synthesis of Quinoxaline Derivatives by Selective Modification of 3‐Chloro‐6‐fluoroquinoxalin‐2(1H)‐one 4‐Oxide
Authors: Maichrowski Jan , Gjikaj Mimoza , Hübner Eike G. , Bergmann Bärbel , Müller Ingrid B. , Kaufmann Dieter E.
Published: February 2013

The readily available and polyfunctionalized 3‐chloro‐6‐fluoroquinoxalin‐2(1H)‐one 4‐oxide, derived from the efficient one‐step annulation reaction of 1,1,2‐trichloro‐2‐nitroethene with 4‐fluoroaniline, was selectively modified at the chloronitrone and the amide units, leading to more than 30 new quinoxaline derivatives with a unique substitution pattern in good to excellent yields. In addition, the electronic properties of the versatile starting compound were computed by means of density functional theory, which gave a reasonable explanation for its unique reactivity. The antimalarial activity of all hitherto unknown compounds has been investigated.
Parametric finite element analysis of FRP reinforced concrete beams in fire and design guidelines
Authors: Rafi Muhammad Masood , Nadjai Ali
Published: February 2013

FRP bars are made of innovative materials, and use of these bars in residential and commercial buildings and infrastructure could result in their increased applications. This requires establishment of fire resistance of the FRP bar RC. This paper describes the results of a parametric study that was carried out on hybrid and carbon FRP bar RC beams. The influence of concrete strength and load ratio on the high temperature performance of beams was investigated. The study used finite element modelling and was conducted with the help of numerical models that were calibrated previously by the authors against the data of experimentally tested beams. It was found that the beam strength and stiffness reduce in the same proportion between two consecutive load ratios and are nearly uninfluenced by the concrete strength. The amount of load was found to be a critical factor for the beam thermal resistance. Preliminary guidance for FRP RC beam design in fire situation is provided on the basis of findings of the study. Copyright © 2013 John Wiley & Sons, Ltd.
Atmospheric CO2 response to volcanic eruptions: The role of ENSO, season, and variability
Authors: Frölicher Thomas Lukas , Joos Fortunat , Raible Christoph Cornelius , Sarmiento Jorge Louis
Published: February 2013

Tropical explosive volcanism is one of the most important natural factors that significantly impact the climate system and the carbon cycle on annual to multi‐decadal time scales. The three largest explosive eruptions in the last 50 years—Agung, El Chichón, and Pinatubo—occurred in spring/summer in conjunction with El Niño events and left distinct negative signals in the observational temperature and CO2 records. However, confounding factors such as seasonal variability and El Niño‐Southern Oscillation (ENSO) may obscure the forcing‐response relationship. We determine for the first time the extent to which initial conditions, i.e., season and phase of the ENSO, and internal variability influence the coupled climate and carbon cycle response to volcanic forcing and how this affects estimates of the terrestrial and oceanic carbon sinks. Ensemble simulations with the Earth System Model (Climate System Model 1.4‐carbon) predict that the atmospheric CO2 response is ˜60% larger when a volcanic eruption occurs during El Niño and in winter than during La Niña conditions. Our simulations suggest that the Pinatubo eruption contributed 11 ± 6% to the 25 Pg terrestrial carbon sink inferred over the decade 1990–1999 and −2 ± 1% to the 22 Pg oceanic carbon sink. In contrast to recent claims, trends in the airborne fraction of anthropogenic carbon cannot be detected when accounting for the decadal‐scale influence of explosive volcanism and related uncertainties. Our results highlight the importance of considering the role of natural variability in the carbon cycle for interpretation of observations and for data‐model intercomparison.
The Induction of Phagocytic Activation by Mixtures of the Water Chlorination By‐Products, Dichloroacetate‐ and Trichloroacetate, in Mice after Subchronic Exposure
Authors: Hassoun Ezdihar A. , Cearfoss Jacquelyn , Musser Brian , Krispinsky Sarah , Al‐Hassan Noor , Liu Ming‐Cheh
Published: February 2013

In this study, groups of B6C3F1 male mice were treated with dichloroacetate (DCA), trichloroacetate (TCA), and mixtures of the compounds (Mix I, II, and III) daily by gavage, for 13 weeks. The tested doses were 7.5, 15, and 30 mg DCA/kg/day and 12.5, 25, and 50 mg TCA/kg/day. The DCA: TCA ratios in Mix I, II, and III were 7.5:12.5, 15:25, and 30:50 mg/kg/day, respectively. Peritoneal lavage cells were collected at the end of the treatment period and assayed for the biomarkers of phagocytic activation, including superoxide anion and tumor necrosis factor‐alpha production, and myeloperoxidase activity. The mixtures produced nonlinear effects on the biomarkers of phagocytic activation, with Mix I and II effects were found to be additive, but Mix III effects were found to be less than additive. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:237‐242, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.21476
Deoxynivalenol impairs the immune functions of neutrophils
Authors: Gauthier Thierry , Waché Yann , Laffitte Joëlle , Taranu Ionelia , Saeedikouzehkonani Nazli , Mori Yasuyuki , Oswald Isabelle P.
Published: February 2013

Scope

Deoxynivalenol (DON), a mycotoxin produced by Fusarium spp., is toxic to many animal species, with pigs being the most sensitive species to the toxin. The aim of the present study was to determine the effects of DON on pig polymorphonuclear cells (PMNs), the first line of defense against infection.

Methods and results

PMNs isolated from pig blood samples were stimulated with LPS to mimic infection. DON (0.5–10 μM) altered three main functions of pig PMNs: LPS‐induced secretion of IL‐8, chemotaxis, and phagocytosis capability. This alteration of PMN properties was due to apoptotis induced by DON exposure. Using Western blot and flow cytometry, we demonstrated that this process included the permeabilization of the mitochondrial outer membrane and the activation of caspase‐3. The effect of DON was mediated by the phosphorylation of the p38 mitogen‐activated protein kinase within the first 30 min of exposure.

Conclusion

This study provides evidence that low concentrations of DON can alter the immune functions of porcine PMNs and suggests the involvement of p38 mitogen‐activated protein kinase in the signal transduction pathway. These immunosuppressive effects of DON may have implications for humans and/or animals when eating contaminated food/feed.
Improved excitation uniformity in multiple‐quantum NMR experiments of mixtures
Authors: Manjunatha Reddy G.N. , Caldarelli S.
Published: February 2013

Multiple‐quantum1H NMR spectroscopy has been finding a renewed interest for its possible applications in the analysis of mixtures of small molecules, due to its simplification properties. A crucial aspect of this application of multiple‐quantum NMR is the sensitivity of the spectrum intensity to the molecular structure and to the parameterization of the experiment, which could result in the missing of some components. We demonstrate that a general scheme to overcome this drawback consists in varying the experiment parameterizations over a small number of values, selected according the values of the couplings and the relaxation rates. Copyright © 2013 John Wiley & Sons, Ltd.
Analyses of the Iridoid Glucoside Dimers in Paederia scandens Using HPLC–ESI–MS/MS
Authors: Lu Chen‐Ceng , Wang Jian‐Hua , Fang Dong‐Mei , Wu Zhi‐Jun , Zhang Guo‐Lin
Published: February 2013

Introduction

Many dimers consisting of structurally similar monomers are difficult to be identified even using NMR. Rapid structural identification of iridoid glycoside dimers, especially isomeric dimers in a complicated matrix, remains desirable.

Objective

To develop a rapid, sensitive analytical method for structural elucidation of trace iridoid glycoside isomers in a complicated extract.

Methods

Three isomeric iridoid glucoside dimers, paederoscandoside, saprosmoside E and saprosmoside D, were isolated and further analysed by electrospray ionisation quadrupole time‐of‐flight tandem mass spectrometry (ESI–QTOF–MS/MS) in positive‐ion mode. Energy‐resolved mass spectrometry (ERMS) was used to provide information on the relative intensity of ions versus collision energy. The crude extract of Paederia scandens was analysed by HPLC–ESI–MS/MS.

Results

The relative abundance of product ions in the MS/MS spectra from ammonium adduct ions varied greatly for the three isomers. The energy‐resolved experiments enhanced differences among the three isomers. A total of 13 iridoid glucoside dimers (three groups of isomers) in the extract of P. scandens were identified or tentatively characterised by using HPLC–ESI–QTOF based on the tandem mass spectra of references.

Conclusion

Linkage sites between different hydroxyl groups on the sugar and carboxyl groups for the three groups of isomers are confirmed. The reason for fragmentation differences might be that cleavage of the glycosidic bond accompanies the active H in vicinal hydroxyl rearrangement. The MS method is a useful tool for the analysis of isomers, especially trace isomers in a complicated extract. Copyright © 2013 John Wiley & Sons, Ltd.
Simultaneous Determination of Five Bioactive Components in Radix Glycyrrhizae by Pressurised Liquid Extraction Combined with UPLC–PDA and UPLC/ESI–QTOF–MS Confirmation
Authors: Zhou Shujun , Cao Jiliang , Qiu Feng , Kong Weijun , Yang Shihai , Yang Meihua
Published: February 2013

Introduction

Glycyrrhizae species are popular ingredients of herbal medicine in most traditional Chinese medicine prescriptions, and they mainly contain flavonoids and triterpene saponins. The contents of these bioactive compounds may vary in different batches and affect the therapeutic effects. Thus comprehensive quality control and monitoring of their herbal formulation are of paramount concern.

Objective

To establish a rapid, effective pressurised liquid extraction (PLE) and ultra‐performance liquid chromatography coupled with photodiode array (UPLC–PDA) method to evaluate the quality of Glycyrrhizae species.

Methods

Radix Glycyrrhizae was extracted by PLE using 70% ethanol at 100°C for 15 min during three static extraction cycles. Separation was performed using an UPLC system to quantify five bioactive compounds, namely liquiritin apioside, liquiritin, liquiritigenin, glycyrrhizic acid and glycyrrhetinic acid, in 12 batches of samples of different origins in China. Furthermore, the samples were analysed using an ultra‐performance liquid chromatography coupled with electrospray ionisation and time‐of‐flight mass spectrometry (UPLC/ESI–QTOF–MS) system to confirm the results.

Results

The calibration curves of all five analytes showed good linearity (R2 > 0.9997). Accuracy, precision and repeatability were all within required limits. The mean recoveries measured at the three concentrations were higher than 93.7% with RSDs lower than < 3.33% for the targets.

Conclusion

The established PLE and UPLC–PDA method could serve as a rapid and effective method for quality evaluation of Radix Glycyrrhizae. The UPLC technique can be considered as an attractive alternative to HPLC in routine quality control of Chinese medicine, especially in situations where high sample throughput and fast analytical speed are required. Copyright © 2013 John Wiley & Sons, Ltd.
Crystal band structure from the embedded cluster
Authors: Boyko Maksim A. , Abarenkov Igor V.
Published: February 2013

The embedded cluster method for ion–covalent crystal band structure calculations is proposed. This method uses the results of embedded cluster electronic structure calculations within one‐determinant Hartree–Fock approximations. The band structure of high‐temperature cubic phase ZrO2 crystal is calculated and found to be in good agreement with calculations in the literature, which applied periodic boundary conditions at the same theory level. © 2013 Wiley Periodicals, Inc.
Writing Scale Development and Use Within a Language Program
Authors: Plakans Lia
Published: February 2013

Developing assessments within a program can create more useful measures of our students' language. This includes rating scales used in performance assessments such as writing or speaking tests. This article describes the process of development, use, and revision of a writing placement scale by teachers in an intensive English language program. To develop the scale, writing from students in the program was examined by instructors to create a data‐driven scale. After piloting, the scale underwent years of use and continued study. This sustained investigation of the scale led to revisions, but also to confidence and program fit. Following the narrative of the scale reveals a process for programs to develop and evaluate measures locally with teacher involvement.
Synthesis, Structures, and Magnetic Properties of Two Tetranuclear Copper Complexes with End‐on Azido and Phenoxo Bridges Containing Chiral Schiff Base Ligands
Authors: Hou Xiao‐Kang , Wu Lin‐Fei , Xiao Hong‐Ping , Li Ming‐Xing , Zhu Shou‐Rong , Wang Zhao‐Xi
Published: February 2013

The copper complexes [Cu4(μ‐L1)2(μ1, 1‐N3)2·(CH3O)2] (1) and [Cu4(μ‐L2)2(μ1, 1‐N3)2(N3)2]·(H2O)2(2) [H2L1= (1R,3S)‐N′,N′′‐bis[salicylidene]‐1, 3‐diamino‐1, 2, 2‐trimethylcyclopentane and H2L2= (1R,3S)‐N′,N′′‐bis[5‐methylsalicylidene]‐1, 3‐diamino‐1, 2, 2‐trimethylcyclopentane] were synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single crystal X‐ray diffraction. Both are tetranuclear complexes consisting of dinuclear copper moieties [Cu2L1]2+or [Cu2L2]2+connected by two end‐on azido bridges. Low temperature magnetic studies indicate that weak antiferromagnetic couple dominates in1and2.
Morphology and taxonomy of Dinophysis species of the section Hastata (Dinoflagellata), including the description of Dinophysis conjuncta sp. nov., from the Mexican marine waters
Authors: Esqueda-Lara Karina , Parra-Toriz Dulce , Hernández-Becerril David U.
Published: February 2013

There have been recent attempts to improve our knowledge about dinoflagellates of the order Dinophysales either in Mexican marine waters or worldwide, and although new records and even new species have reliable illustrations and descriptions, this group is so diverse that it needs to be studied in more detail. This paper is the product of the analysis of net phytoplankton material collected from coasts of the tropical Mexican Pacific (Gulf of California, Central Mexican Pacific and Gulf of Tehuantepec), and the southern Gulf of Mexico. Material was studied using light microscopy and scanning electron microscopy (SEM). Eleven taxa (10 species and one variety) of the section Hastata were fully identified, with nine species studied for the first time by electron microscopy (only Dinophysis hastata and D. schuettii had been previously studied by SEM), and including seven new records for the Mexican Pacific (Dinophysis monacantha, D. nias, D. phalacromoides, D. pusilla, D. swezyae, D. uracantha var. mediterranea, and D. uracanthoides), and one new record for the Gulf of Mexico (Dinophysis uracanthoides). Two species remain as unidentified, as only one specimen of each was found. Additionally, we studied in detail the new species, Dinophysis conjuncta sp. nov., for which a full description is provided. Descriptions, measurements, illustrations and local distribution data are provided for each species.
Stereotypical behaviour in captive West Indian manatee (Trichechus manatus)
Authors: Anzolin Daiane Garcia , de Carvalho Paulo S.M. , Viana Pitágoras C. , Normande Iran C. , Souto Antonio da Silva
Published: February 2013

There is great difficulty in maintaining aquatic mammals in captivity, since the attempt to replicate the environment they live in poses an enormous challenge. Poor captivity facilities without environmental enrichment can lead to different consequences for animal health, including the appearance of stereotypical movements. The aim of this study was to identify these behaviours in three groups of animals, one group of manatees inhabiting a reintroduction oceanarium in Pernambuco (PE) state, and two other groups confined in corrals constructed in natural areas (estuaries), one located in Paraiba state and the other in Alagoas state, all in north-eastern Brazil. Observations were conducted using the focal animal sampling method. It was found that the animals inhabiting the reintroduction oceanarium with no environmental enrichment showed stereotypical behaviour such as ‘Back-and-forth’ movements, ‘Hitting head against the limiting structure’ and ‘Hitting the muzzle’, while animals constrained within estuaries did not. The ‘circle swimming’ behaviour was present in a higher percentage of the animals captive in the reintroduction oceanarium, although no significant difference between the sites was found. The number and frequency of occurrence of stereotypical behaviours was significantly higher in animals kept in the reintroduction oceanarium in PE than in those of other locations. Based on these results we recommend the use of appropriate environmental enrichment and the reduction of time manatees stay confined in the reintroduction oceanarium.
Retrospective analysis of whole genome sequencing compared to prospective typing data in further informing the epidemiological investigation of an outbreak of Shigella sonnei in the UK
Authors: McDONNELL J. , DALLMAN T. , ATKIN S. , TURBITT D. A. , CONNOR T. R. , GRANT K. A. , THOMSON N. R. , JENKINS C.
Published: February 2013

The aim of this study was to retrospectively assess the value of whole genome sequencing (WGS) compared to conventional typing methods in the investigation and control of an outbreak of Shigella sonnei in the Orthodox Jewish (OJ) community in the UK. The genome sequence analysis showed that the strains implicated in the outbreak formed three phylogenetically distinct clusters. One cluster represented cases associated with recent exposure to a single strain, whereas the other two clusters represented related but distinct strains of S. sonnei circulating in the OJ community across the UK. The WGS data challenged the conclusions drawn during the initial outbreak investigation and allowed cases of dysentery to be implicated or ruled out of the outbreak that were previously misclassified. This study showed that the resolution achieved using WGS would have clearly defined the outbreak, thus facilitating the promotion of infection control measures within local schools and the dissemination of a stronger public health message to the community.
Viral load of human bocavirus-1 in stools from children with viral diarrhoea in Paraguay
Authors: PROENCA-MODENA J. L. , MARTINEZ M. , AMARILLA A. A. , ESPÍNOLA E. E. , GALEANO M. E. , FARIÑA N. , RUSSOMANDO G. , AQUINO V. H. , PARRA G. I. , ARRUDA E.
Published: February 2013

Since their discovery, four species of human bocavirus (HBoV) have been described in patients with respiratory and gastrointestinal diseases. However, a clear causal association between HBoV-1 and gastroenteritis has not been demonstrated. In this study, we describe the detection and quantification of HBoV-1 in stools from children with acute non-bacterial gastroenteritis using quantitative polymerase chain reaction. HBoV-1 genome was detected in 10·6% of stools with frequent association with rotavirus and norovirus. The median of HBoV-1 viral load was 1·88 × 104 genome/ml, lower than previously shown in secretions of patients with respiratory infections, without any obvious association between high viral load and presence of HBoV as single agent. Thus, although HBoV-1 was frequently detected in these patients, there is no clear causal association of this agent with diarrhoea. Indeed, HBoV-1 DNA in stools of patients with gastroenteritis without respiratory symptoms may be a remnant of previous infections or associated with prolonged shedding of virus in the respiratory or digestive tracts.
‘Model-Platonism’ in economics: on a classical epistemological critique
Authors: KAPELLER JAKOB
Published: February 2013

Roughly 50 years ago, the eminent German philosopher and social scientist Hans Albert presented a critique of ‘Model-Platonism’ in economics to describe essential elements of the ‘neoclassical style of economic reasoning’. Specifically, Albert advanced a series of epistemological arguments to illustrate conceptual shortcomings in neoclassical theory, which may be utilized to immunize the latter against conflicting empirical evidence. This article summarizes Albert's main arguments and illustrates his most important insights by using simple propositional logic. Based on these findings, a clarification and definition of ‘Model-Platonism’ is offered and the applicability of the Model-Platonism-critique to current developments in mainstream economics is assessed. Finally, two possible extensions of Albert's argument, the concepts ofoscillating informational contentandaxiomatic variation, are illustrated with respect to their potential for immunization against critique.
Epidemiology of Twin Births in Southeast China: 1993–2005
Authors: Lu Xinrong , Zhang Jun , Liu Yinghui , Wang Ting , Lu Yanyu , Li Zhu
Published: February 2013

Recently, there has been a significant increase in the rate of multiple births in most developed countries. However, few population-based studies have been conducted in China regarding the epidemiology of twin births in recent years. We performed a descriptive analysis of twin births from 1993 to 2005 using data from a population-based perinatal care program in southeast China. The twin birth rate in southeast China was 0.65%, and the twin birth rates from 1993 to 2005 fluctuated between 0.60% and 0.70%. During the three periods of 1993–1996, 1997–2000, and 2001–2005, the twin birth rate increased from 0.57% to 0.71% in urban areas (p= .005) and from 0.59% to 0.68% in mothers who had an education level of high school or higher (p= .046). After 2000, the twin birth rate of primiparae 30 years of age and older significantly increased from 0.72% to greater than 1.20%. We concluded that the twin birth rates in southeast China from 1993 to 2005 stayed constant in the overall population but increased in certain subgroups of women, presumably due to increased use of fertility treatment and the development of assisted reproductive technology.
The species-rich assemblages of tintinnids (marine planktonic protists) are structured by mouth size
Authors: Dolan John R , Landry Michael R , Ritchie Mark E
Published: February 2013

Many microbial taxa in the marine plankton appear super-saturated in species richness. Here, we provide a partial explanation by analyzing how species are organized, species packing, in terms of both taxonomy and morphology. We focused on a well-studied group, tintinnid ciliates of the microzooplankton, in which feeding ecology is closely linked to morphology. Populations in three distinct systems were examined: an Eastern Mediterranean Gyre, a Western Mediterranean Gyre and the California Current. We found that species abundance distributions exhibited the long-tailed, log distributions typical of most natural assemblages of microbial and other organisms. In contrast, grouping in oral size-classes, which corresponds with prey-size exploited, revealed a geometric distribution consistent with a dominant role of a single resource in structuring an assemblage. The number of species found in a particular oral size-class increases with the numerical importance of the size-class in the overall population. We suggest that high species diversity reflects the fact that accompanying each dominant species are many ecologically similar species, presumably able to replace the dominant species, at least with regard to the size of prey exploited. Such redundancy suggests that species diversity greatly exceeds ecological diversity in the plankton.
Unexpected weak magnetic exchange coupling between haem and non-haem iron in the catalytic site of nitric oxide reductase (NorBC) from Paracoccus denitrificans
Authors: Van Wonderen Jessica H. , Oganesyan Vasily S. , Watmough Nicholas J. , Richardson David J. , Thomson Andrew J. , Cheesman Myles R.
Published: February 2013

Bacterial NOR (nitric oxide reductase) is a major source of the powerful greenhouse gas N2O. NorBC from Paracoccus denitrificans is a heterodimeric multi-haem transmembrane complex. The active site, in NorB, comprises high-spin haem b3 in close proximity with non-haem iron, FeB. In oxidized NorBC, the active site is EPR-silent owing to exchange coupling between FeIII haem b3 and FeBIII (both S=5/2). On the basis of resonance Raman studies [Moënne-Loccoz, Richter, Huang, Wasser, Ghiladi, Karlin and de Vries (2000) J. Am. Chem. Soc. 122, 9344–9345], it has been assumed that the coupling is mediated by an oxo-bridge and subsequent studies have been interpreted on the basis of this model. In the present study we report a VFVT (variable-field variable-temperature) MCD (magnetic circular dichroism) study that determines an isotropic value of J=−1.7 cm−1 for the coupling. This is two orders of magnitude smaller than that encountered for oxo-bridged diferric systems, thus ruling out this configuration. Instead, it is proposed that weak coupling is mediated by a conserved glutamate residue.
Insights into antiamyloidogenic properties of the green tea extract (−)-epigallocatechin-3-gallate toward metal-associated amyloid-β species
Authors: Hyung Suk-Joon , DeToma Alaina S. , Brender Jeffrey R. , Lee Sanghyun , Vivekanandan Subramanian , Kochi Akiko , Choi Jung-Suk , Ramamoorthy Ayyalusamy , Ruotolo Brandon T. , Lim Mi Hee
Published: February 2013

Despite the significance of Alzheimer’s disease, the link between metal-associated amyloid-β (metal–Aβ) and disease etiology remains unclear. To elucidate this relationship, chemical tools capable of specifically targeting and modulating metal–Aβ species are necessary, along with a fundamental understanding of their mechanism at the molecular level. Herein, we investigated and compared the interactions and reactivities of the green tea extract, (−)-epigallocatechin-3-gallate [(2
R
,3
R
)-5,7-dihydroxy-2-(3,4,5-trihydroxyphenyl)-3,4-dihydro-2
H
-1-benzopyran-3-yl 3,4,5-trihydroxybenzoate; EGCG], with metal [Cu(II) and Zn(II)]–Aβ and metal-free Aβ species. We found that EGCG interacted with metal–Aβ species and formed small, unstructured Aβ aggregates more noticeably than in metal-free conditions in vitro. In addition, upon incubation with EGCG, the toxicity presented by metal-free Aβ and metal–Aβ was mitigated in living cells. To understand this reactivity at the molecular level, structural insights were obtained by ion mobility-mass spectrometry (IM-MS), 2D NMR spectroscopy, and computational methods. These studies indicated that (
i
) EGCG was bound to Aβ monomers and dimers, generating more compact peptide conformations than those from EGCG-untreated Aβ species; and (
ii
) ternary EGCG–metal–Aβ complexes were produced. Thus, we demonstrate the distinct antiamyloidogenic reactivity of EGCG toward metal–Aβ species with a structure-based mechanism.
Inactivation ofCaenorhabditis elegansaminopeptidase DNPP-1 restores endocytic sorting and recycling intat-1mutants
Authors: Li Xin , Chen Baohui , Yoshina Sawako , Cai Tanxi , Yang Fuquan , Mitani Shohei , Wang Xiaochen
Published: February 2013

In Caenorhabditis elegans, the P4-ATPase TAT-1 and its chaperone, the Cdc50 family protein CHAT-1, maintain membrane phosphatidylserine (PS) asymmetry, which is required for membrane tubulation during endocytic sorting and recycling. Loss of tat-1 and chat-1 disrupts endocytic sorting, leading to defects in both cargo recycling and degradation. In this study, we identified the C. elegans aspartyl aminopeptidase DNPP-1, loss of which suppresses the sorting and recycling defects in tat-1 mutants without reversing the PS asymmetry defect. We found that tubular membrane structures containing recycling cargoes were restored in dnpp-1 tat-1 double mutants and that these tubules overlap with RME-1–positive recycling endosomes. The restoration of the tubular structures in dnpp-1 tat-1 mutants requires normal functions of RAB-5, RAB-10, and RME-1. In tat-1 mutants, we observed alterations in membrane surface charge and targeting of positively charged proteins that were reversed by loss of dnpp-1. DNPP-1 displays a specific aspartyl aminopeptidase activity in vitro, and its enzymatic activity is required for its function in vivo. Our data reveal the involvement of an aminopeptidase in regulating endocytic sorting and recycling and suggest possible roles of peptide signaling and/or protein metabolism in these processes.
Doc2b promotes GLUT4 exocytosis by activating the SNARE-mediated fusion reaction in a calcium- and membrane bending–dependent manner
Authors: Yu Haijia , Rathore Shailendra S. , Davis Eric M. , Ouyang Yan , Shen Jingshi
Published: February 2013

The glucose transporter GLUT4 plays a central role in maintaining body glucose homeostasis. On insulin stimulation, GLUT4-containing vesicles fuse with the plasma membrane, relocating GLUT4 from intracellular reservoirs to the cell surface to uptake excess blood glucose. The GLUT4 vesicle fusion reaction requires soluble N-ethylmaleimide–sensitive factor attachment protein receptors (SNAREs) as the core fusion engine and a group of regulatory proteins. In particular, the soluble C2-domain factor Doc2b plays a key role in GLUT4 vesicle fusion, but its molecular mechanism has been unclear. Here we reconstituted the SNARE-dependent GLUT4 vesicle fusion in a defined proteoliposome fusion system. We observed that Doc2b binds to GLUT4 exocytic SNAREs and potently accelerates the fusion kinetics in the presence of Ca2+. The stimulatory activity of Doc2b requires intact Ca2+-binding sites on both the C2A and C2B domains. Using electron microscopy, we observed that Doc2b strongly bends the membrane bilayer, and this membrane-bending activity is essential to the stimulatory function of Doc2b in fusion. These results demonstrate that Doc2b promotes GLUT4 exocytosis by accelerating the SNARE-dependent fusion reaction by a Ca2+- and membrane bending–dependent mechanism. Of importance, certain features of Doc2b function appear to be distinct from how synaptotagmin-1 promotes synaptic neurotransmitter release, suggesting that exocytic Ca2+ sensors may possess divergent mechanisms in regulating vesicle fusion.
A novel medical image data-based multi-physics simulation platform for computational life sciences
Authors: Neufeld Esra , Szczerba Dominik , Chavannes Nicolas , Kuster Niels
Published: February 2013

Simulating and modelling complex biological systems in computational life sciences requires specialized software tools that can perform medical image data-based modelling, jointly visualize the data and computational results, and handle large, complex, realistic and often noisy anatomical models. The required novel solvers must provide the power to model the physics, biology and physiology of living tissue within the full complexity of the human anatomy (e.g. neuronal activity, perfusion and ultrasound propagation). A multi-physics simulation platform satisfying these requirements has been developed for applications including device development and optimization, safety assessment, basic research, and treatment planning. This simulation platform consists of detailed, parametrized anatomical models, a segmentation and meshing tool, a wide range of solvers and optimizers, a framework for the rapid development of specialized and parallelized finite element method solvers, a visualization toolkit-based visualization engine, a P
ython
scripting interface for customized applications, a coupling framework, and more. Core components are cross-platform compatible and use open formats. Several examples of applications are presented: hyperthermia cancer treatment planning, tumour growth modelling, evaluating the magneto-haemodynamic effect as a biomarker and physics-based morphing of anatomical models.