bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron Transfer and Multi‐Electron Accumulation in ExBox4+
Authors: Dyar Scott M. , Barnes Jonathan C. , Juríček Michal , Stoddart J. Fraser , Co Dick T. , Young Ryan M. , Wasielewski Michael R.
Published: May 2014

Molecules capable of accepting and storing multiple electrons are crucial components of artificial photosynthetic systems designed to drive catalysts, such as those used to reduce protons to hydrogen. ExBox4+, a boxlike cyclophane comprising two π‐electron‐poor extended viologen units tethered at both ends by two p‐xylylene linkers, has been shown previously to accept an electron through space from a photoexcited guest. Herein is an investigation of an alternate, through‐bond intramolecular electron‐transfer pathway involving ExBox4+ using a combination of transient absorption and femtosecond stimulated Raman spectroscopy (FSRS). Upon photoexcitation of ExBox4+, an electron is transferred from one of the p‐xylylene linkers to one of the extended viologen units in ca. 240 ps and recombines in ca. 4 ns. A crystal structure of the doubly reduced species ExBox2+ was obtained.
Stress reduction in phase‐separated, cross‐linked networks: Influence of phase structure and kinetics of reaction
Authors: Szczepanski Caroline R. , Stansbury Jeffrey W.
Published: May 2014

A mechanism for polymerization shrinkage and stress reduction was developed for heterogeneous networks formed through ambient, photo‐initiated polymerization‐induced phase separation (PIPS). The material system used consists of a bulk homopolymer matrix of triethylene glycol dimethacrylate (TEGDMA) modified with one of three nonreactive, linear prepolymers (poly‐methyl, poly‐ethyl, and poly‐butyl methacrylate). At higher prepolymer loading levels (10–20 wt %), an enhanced reduction in both shrinkage and polymerization stress is observed. The onset of gelation in these materials is delayed to a higher degree of methacrylate conversion (∼15–25%), providing more time for phase structure evolution by thermodynamically driven monomer diffusion between immiscible phases prior to network macro‐gelation. The resulting phase structure was probed by introducing a fluorescently tagged prepolymer into the matrix. The phase structure evolves from a dispersion of prepolymer at low loading levels to a fully co‐continuous heterogeneous network at higher loadings. The bulk modulus in phase‐separated networks is equivalent or greater than that of poly(TEGDMA), despite a reduced polymerization rate and cross‐link density in the prepolymer‐rich domains. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40879.
A sensitive voltammetric sensor based on synergistic effect of graphene–polyaniline hybrid film for quantification of calcium antagonist lercanidipine
Authors: Jain Rajeev , Tiwari Dinesh Chandra , Shrivastava Swati
Published: May 2014

A chemically modified sensor based on the synergistic effect of graphene and polyaniline for electrochemical sensing of calcium antagonist lercanidipine (LCP) has been developed. Scanning electron microscopy, electrochemical impedance spectroscopy, square‐wave voltammetry, and cyclic voltammetry were utilized to characterize the morphology and electroanalytical performance of the fabricated sensor. Under optimized conditions, reduction peak current was linear over the wide concentration range from 5 to 125 ng mL−1with correlation coefficient of 0.9998. The limit of detection and the limit of quantification were found to be 1.94 and 5.89 ng mL−1. The developed sensor also exhibited good reproducibility and long‐term stability. In addition, the proposed method was successfully applied to the determination of LCP in pharmaceutical formulation which is proved by recovery studies. Graphene–polyaniline composites are expected to be promising material for biosensing applications because of the ease of fabrication, excellent electrochemical performance, and high electroactive surface area. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 40959.
ResearchGate: Disseminating, communicating, and measuring Scholarship?
Authors: Thelwall Mike , Kousha Kayvan
Published: May 2014

ResearchGate is a social network site for academics to create their own profiles, list their publications, and interact with each other. Like Academia.edu, it provides a new way for scholars to disseminate their work and hence potentially changes the dynamics of informal scholarly communication. This article assesses whether ResearchGate usage and publication data broadly reflect existing academic hierarchies and whether individual countries are set to benefit or lose out from the site. The results show that rankings based on ResearchGate statistics correlate moderately well with other rankings of academic institutions, suggesting that ResearchGate use broadly reflects the traditional distribution of academic capital. Moreover, while Brazil, India, and some other countries seem to be disproportionately taking advantage of ResearchGate, academics in China, South Korea, and Russia may be missing opportunities to use ResearchGate to maximize the academic impact of their publications.
Sample‐size calculation and reestimation for a semiparametric analysis of recurrent event data taking robust standard errors into account
Authors: Ingel Katharina , Jahn‐Eimermacher Antje
Published: May 2014

In some clinical trials, the repeated occurrence of the same type of event is of primary interest and the Andersen–Gill model has been proposed to analyze recurrent event data. Existing methods to determine the required sample size for an Andersen–Gill analysis rely on the strong assumption that all heterogeneity in the individuals' risk to experience events can be explained by known covariates. In practice, however, this assumption might be violated due to unknown or unmeasured covariates affecting the time to events. In these situations, the use of a robust variance estimate in calculating the test statistic is highly recommended to assure the type I error rate, but this will in turn decrease the actual power of the trial. In this article, we derive a new sample‐size formula to reach the desired power even in the presence of unexplained heterogeneity. The formula is based on an inflation factor that considers the degree of heterogeneity and characteristics of the robust variance estimate. Nevertheless, in the planning phase of a trial there will usually be some uncertainty about the size of the inflation factor. Therefore, we propose an internal pilot study design to reestimate the inflation factor during the study and adjust the sample size accordingly. In a simulation study, the performance and validity of this design with respect to type I error rate and power are proven. Our method is applied to the HepaTel trial evaluating a new intervention for patients with cirrhosis of the liver.
Rapid avatar capture and simulation using commodity depth sensors
Authors: Shapiro Ari , Feng Andrew , Wang Ruizhe , Li Hao , Bolas Mark , Medioni Gerard , Suma Evan
Published: May 2014

We demonstrate a method of acquiring a 3D model of a human using commodity scanning hardware and then controlling that 3D figure in a simulated environment in only a few minutes. The model acquisition requires four static poses taken at 90° angles relative to each other. The 3D model is then given a skeleton and smooth binding information necessary for control and simulation. The 3D models that are captured are suitable for use in applications where recognition and distinction among characters by shape, form, or clothing is important, such as small group or crowd simulations or other socially oriented applications. Because of the speed at which a human figure can be captured and the low hardware requirements, this method can be used to capture, track, and model human figures as their appearances change over time. Copyright © 2014 John Wiley & Sons, Ltd.
Triterpene Saponins from the Roots of Ilex asprella
Authors: Lei Yu , Shi She‐Po , Song Yue‐Lin , Bi Dan , Tu Peng‐Fei
Published: May 2014

Six new triterpene saponins, ilexasprellanosides A–F (1–6, resp.), together with eleven known compounds were isolated from the roots of Ilex asprella. The new saponins were characterized as ursa‐12,18‐dien‐28‐oic acid 3‐O‐β‐D‐xylopyranoside (1), 19α‐hydroxyursolic acid 3‐O‐β‐D‐(2′‐O‐acetylxylopyranoside) (2), 19α‐hydroxyursolic acid 3‐O‐β‐D‐glucuronopyranoside (3), 3β,19α‐dihydroxyolean‐12‐en‐23,28‐dioic acid 28‐O‐β‐D‐glucopyranoside (4), 19α‐hydroxyoleanolic acid 3‐O‐β‐D‐(2′‐O‐acetylxylopyranoside) (5), 19α‐hydroxyoleanolic acid 3‐O‐β‐D‐glucuronopyranoside (6). The structures of the new compounds were elucidated by analysis of their spectroscopic data and chemical degradation. Compounds 2, 4, oleanolic acid 3‐O‐β‐D‐glucuronopyranoside, 3‐β‐acetoxy‐28‐hydroxyurs‐12‐ene, and pomolic acid showed significant cytotoxic activities against human tumor cell line A549 (IC50 values of 1.87, 2.51, 1.41, 3.24, and 5.63 μM, resp.).
Two New Avermectin Derivatives from the Beibu Gulf Gorgonian Anthogorgia caerulea
Authors: Gao Chenghai , Wang Yibing , Chen Yinning , He Bijuan , Zhang Rongcan , Xu Mingben , Huang Riming
Published: May 2014

Two new avermectin derivatives, avermectins B1c and B1e (1 and 2, resp.), as well as two known compounds, avermectin B2a (3) and ivermectin A1a (4), were isolated from a Beibu Gulf gorgonian coral, Anthogorgia caerulea. The structures of the new compounds were established by detailed spectroscopic analysis and by comparison with spectral data of related known compounds. Compounds 1–4 showed moderate antifouling activities against the larval settlement of Balanus amphitrite.
Renal artery stenosis following renal percutaneous denervation
Authors: Bhamra‐Ariza Paul , Rao Sriram , Muller David W
Published: May 2014

Renal denervation has been shown to be safe and effective in reducing blood pressure in treatment‐resistant hypertensive patients. We describe a 65‐year‐old lady with essential hypertension who underwent renal denervation using the Vessix™ single shot multielectrode system. Twelve months later renal duplex scanning documented increased velocities in the left renal artery and repeat angiography confirmed the development of a new stenosis. Although renal denervation is a promising therapy, we advise caution as large randomized blinded studies with long‐term follow‐up are still ongoing. © 2014 Wiley Periodicals, Inc.
Thromboexclusion of an atypical left ventricular pseudoaneurysm
Authors: Srivastava Nayan T. , Hoyer Mark H.
Published: May 2014

Left ventricular pseudoaneurysm is rare in children. The gold standard for treatment has been surgical repair. Here, we describe a boy in whom an atypical left ventricular pseudoaneurysm was treated through staged transcatheter procedures. In addition, we highlight the importance of the preprocedure cardiac magnetic resonance imaging in providing invaluable information that allowed detailed planning of a management strategy for this unusual pseudoaneurysm. © 2014 Wiley Periodicals, Inc.
Construction of a MoxC/Ni Network Electrode with Low Overpotential for Hydrogen Generation
Authors: Zhang Jian , Meng Xin , Zhao Jianghong , Zhu Zhenping
Published: May 2014

The integration of commercial photovoltaic devices and electrocatalysts has attracted considerable interest to realize the conversion of solar power to renewable hydrogen energy. However, a noble metal electrocatalyst (Pt) is too expensive and rare, which inspires the development of efficient and economical catalytic electrodes. Herein, we have fabricated a 3 D MoxC/Ni network through the carbonization of a polyaniline–Mo7O24 precursor, which was electrochemically deposited on Ni foam in advance. If the 3 D MoxC/Ni network is used as a catalytic electrode for the hydrogen evolution reaction (HER), a low onset potential of approximately 44 mV for driving 1 mA cm−2 of current density and a Tafel slope of approximately 49 mV decade−1 (overpotential η=50–60 mV) are obtained. Moreover, the apparent exchange current density reaches approximately 0.1 mA cm−2. After a long‐term HER test at η=100 mV or 500 CV sweeps, no deactivation is observed. This excellent electrocatalytic performance of the 3 D MoxC/Ni network promotes it as a promising earth‐abundant HER electrode.
Methane Steam Reforming over a Ni/NiAl2O4 Model Catalyst—Kinetics
Authors: Sprung Christoph , Arstad Bjørnar , Olsbye Unni
Published: May 2014

The steam reforming reaction of methane to synthesis gas (CO and H2) was investigated in a very broad steam‐to‐carbon (S/C) ratio range (0.2–7.1) over a Ni/NiAl2O4 catalyst at 843, 858, and 873 K. The dataset includes 179 data points at each temperature giving a detailed insight in the gradual change of kinetic orders in both methane and steam with changing S/C ratios as well as with total reactant partial pressures at differential conversion levels. At low S/C ratios, steam dominates the kinetics with high kinetic orders (low for methane) and vice versa for methane at high S/C ratios. The extent of the water gas shift reaction was assessed by 13CO2 co‐feed experiments and thermodynamic modelling and found to be not in equilibrium. A change in the kinetic isotope effect (i.e., inverse and normal), as well as the apparent activation energy, was observed depending on the applied S/C ratios. The experimental data were satisfactorily described by a Langmuir–Hinshelwood expression.
Epoxidation of Olefins Catalyzed by a Molecular Iron N‐Heterocyclic Carbene Complex: Influence of Reaction Parameters on the Catalytic Activity
Authors: Kück Jens W. , Raba Andreas , Markovits Iulius I. E. , Cokoja Mirza , Kühn Fritz E.
Published: May 2014

The catalytic epoxidation of olefins by an iron(II) complex bearing a tetradentate bis(pyridyl‐N‐heterocyclic carbene) ligand was investigated. This is the first example of the use of an organometallic iron compound (i.e., with a FeC bond) as an olefin epoxidation catalyst. The catalyst system, used without additives, showed good epoxide yields and selectivity for various olefins after a reaction time of 5 min. It was found that the epoxide yield strongly depended on the amount of the peroxide used and its nature and noticeably increased at lower temperatures.
The Primary Steps in Excited‐State Hydrogen Transfer: The Phototautomerization of o‐Nitrobenzyl Derivatives
Authors: Šolomek Tomáš , Bochet Christian G. , Bally Thomas
Published: May 2014

The quantum yield for the release of leaving groups from o‐nitrobenzyl “caged” compounds varies greatly with the nature of these leaving groups, for reasons that have never been well understood. We found that the barriers for the primary hydrogen‐atom transfer step and the efficient nonradiative processes on the excited singlet and triplet surfaces determine the quantum yields. The excited‐state barriers decrease when the exothermicity of the photoreaction increases, in accord with Bell–Evans–Polanyi principle, a tool that has never been applied to a nonadiabatic photoreaction. We further introduce a simple ground‐state predictor, the radical‐stabilization energy, which correlates with the computed excited‐state barriers and reaction energies, and that might be used to design new and more efficient photochemical processes.
Analysis of Dopant Atom Distribution and Quantification of Oxygen Vacancies on Individual Gd‐Doped CeO2 Nanocrystals
Authors: Stroppa Daniel G. , Dalmaschio Cleocir J. , Houben Lothar , Barthel Juri , Montoro Luciano A. , Leite Edson R. , Ramirez Antonio J.
Published: May 2014

This work reports the analysis of the distribution of Gd atoms and the quantification of O vacancies applied to individual CeO2 and Gd‐doped CeO2 nanocrystals by electron energy‐loss spectroscopy. The concentration of O vacancies measured on the undoped system (6.3±2.6 %) matches the expected value given the typical Ce3+ content previously reported for CeO2 nanoparticles. The doped nanoparticles have an uneven distribution of dopant atoms and an atypical amount of O vacant sites (37.7±4.1 %). The measured decrease of the O content induced by Gd doping cannot be explained solely by the charge balance including Ce3+ and Gd3+ ions.
Dendrimeric β‐Cyclodextrin/GdIII Chelate Supramolecular Host–Guest Adducts as High‐Relaxivity MRI Probes
Authors: Martinelli Jonathan , Thangavel Kalaivani , Tei Lorenzo , Botta Mauro
Published: May 2014

We have synthesized a new macromolecular architecture, (PAMAM)‐CD8, which consists of eight β‐cyclodextrin units (β‐CD) attached to a generation 1 poly(amidoamine) (PAMAM) dendrimer through a disulfide bond, which can be cleaved under reducing conditions. This system shows a pronounced hosting capability towards GdIII chelates functionalized with hydrophobic groups, thus leading to well‐defined supramolecular adducts. 1H NMR relaxometric investigations were carried out to follow the formation of adducts with three GdIII chelates based on the ligand architectures of 6‐amino‐6‐methylperhydro‐1,4‐diazepinetetraacetic acid (AAZTA) or 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) suitably functionalized with benzyl or adamantyl (Ad) pendant groups. In particular, the ditopic complex composed of two AAZTA chelating units connected to a central aromatic ring that bears an adamantyl group showed a strong affinity (ca. 106 M−1) for the CD units of the dendrimer, which is two orders of magnitude higher than toward human serum albumin (HSA). Remarkable relaxivity enhancements (i.e., up to 71 % at 1 T and 25 °C) were observed upon the formation of the macromolecular host–guest adducts due to a decrease in the molecular tumbling rate and fast water‐exchange. Reduction experiments and competition studies between the paramagnetic dendrimer and HSA were carried out by relaxometric techniques. The results show that the metal complexes are not displaced by the protein, thus suggesting that this novel macromolecular probe is potentially suitable for applications in vivo.
Synthesis of Chiral Exocyclic Amines by Asymmetric Hydrogenation of Aromatic Quinolin‐3‐amines
Authors: Cai Xian‐Feng , Guo Ran‐Ning , Chen Mu‐Wang , Shi Lei , Zhou Yong‐Gui
Published: May 2014

Asymmetric hydrogenation of aromatic quinolin‐3‐amines was successfully developed with up to 94 % enantiomeric excess (ee). Introduction of the phthaloyl moiety to the amino group is crucial to eliminate the inhibition effect caused by the substrate and product, to activate the aromatic ring, and to improve the diastereoselectivity. This new methodology provides direct and facile access to chiral exocyclic amines. Notably, this report is the first on the highly enantioselective hydrogenation of aromatic amines.
Palladium‐Catalyzed Oxidative Carbocyclization–Carbonylation of Allenynes and Enallenes
Authors: Volla Chandra M. R. , Mazuela Javier , Bäckvall Jan‐E.
Published: May 2014

A highly efficient oxidative carbocyclization–carbonylation reaction cascade of allenynes and enallenes has been developed using a PdII salt in low catalytic amounts under ambient temperature and pressure (1 atm of carbon monoxide). The use of DMSO as an additive was found to be important for an efficient reaction. A wide range of alcohols as trapping reagents were used to give the corresponding esters in good yields.
Kinetic Modeling of α‐Hydrogen Abstractions from Unsaturated and Saturated Oxygenate Compounds by Carbon‐Centered Radicals
Authors: Paraskevas Paschalis D. , Sabbe Maarten K. , Reyniers Marie‐Françoise , Papayannakos Nikos , Marin Guy B.
Published: May 2014

Hydrogen abstractions are important elementary reactions in a variety of reacting media at high temperatures in which oxygenates and hydrocarbon radicals are present. Accurate kinetic data are obtained from CBS‐QB3 ab initio (AI) calculations by using conventional transition‐state theory within the high‐pressure limit, including corrections for hindered rotation and tunneling. From the obtained results, a group‐additive (GA) model is developed that allows the Arrhenius parameters and rate coefficients for abstraction of the α‐hydrogen from a wide range of oxygenate compounds to be predicted at temperatures ranging from 300 to 1500 K. From a training set of 60 hydrogen abstractions from oxygenates by carbon‐centered radicals, 15 GA values (ΔGAVos) are obtained for both the forward and reverse reactions. Among them, four ΔGAVos refer to primary contributions, and the remaining 11 ΔGAVos refer to secondary ones. The accuracy of the model is further improved by introducing seven corrections for cross‐resonance stabilization of the transition state from an additional set of 43 reactions. The determined ΔGAVos are validated upon a test set of AI data for 17 reactions. The mean absolute deviation of the pre‐exponential factors (log A) and activation energies (Ea) for the forward reaction at 300 K are 0.238 log(m3 mol−1 s−1) and 1.5 kJ mol−1, respectively, whereas the mean factor of deviation <ρ> between the GA‐predicted and the AI‐calculated rate coefficients is 1.6. In comparison with a compilation of 33 experimental rate coefficients, the <ρ> between the GA‐predicted values and these experimental values is only 2.2. Hence, the constructed GA model can be reliably used in the prediction of the kinetics of α‐hydrogen‐abstraction reactions between a broad range of oxygenates and oxygenate radicals.
Flavylium Network of Chemical Reactions in Confined Media: Modulation of 3′,4′,7‐Trihydroxyflavilium Reactions by Host–Guest Interactions with Cucurbit[7]uril
Authors: Basílio Nuno , Pina Fernando
Published: May 2014

In moderately acidic aqueous solutions, flavylium compounds undergo a pH‐, and in some cases, light‐dependent array of reversible chemical reactions. This network can be described as a single acid–base reaction involving a flavylium cation (acidic form) and a mixture of basic forms (quinoidal base, hemiketal and cis and trans chalcones). The apparent pK′a of the system and the relative mole fractions of the basic forms can be modulated by the interaction with cucurbit[7]uril. The system is studied by using 1H NMR spectroscopy, UV/Vis spectroscopy, flash photolysis, and steady‐state irradiation. Of all the network species, the flavylium cation possesses the highest affinity for cucurbit[7]uril. The rate of interconversion between flavylium cation and the basic species (where trans‐chalcone is dominant) is approximately nine times lower inside the cucurbit[7]uril.
Growth of Fe3O4 Nanorod Arrays on Graphene Sheets for Application in Electromagnetic Absorption Fields
Authors: Zhang Huanming , Zhu Chunling , Chen Yujin , Gao Hong
Published: May 2014

A facial strategy is developed to fabricate a three‐dimensional (3D) Fe3O4 nanorod array/graphene architecture, in which Fe3O4 nanorods with a length and diameter of about 600 and 100 nm, respectively, are grown on both surfaces of the graphene sheets. The measured electromagnetic parameters show that the 3D architecture exhibits excellent electromagnetic wave‐absorption properties, that is, more than 99 % of electromagnetic wave energy can be attenuated by the 3D architecture if it is added in only 20 wt % of the paraffin matrix, as the thickness of the absorber is in the range from 2.38 to 5.00 mm. The analysis of the electromagnetic (EM) absorption mechanism reveals that the excellent EM absorption properties are related to the special 3D architecture, and therefore, the construction of graphene‐based 3D heteronanostructures is effective in obtaining lightweight EM absorbers with strong absorption properties.
Movable partition designed for the seed‐assisted silicon ingot casting in directional solidification process
Authors: Ding Changlin , Huang Meiling , Zhong Genxiang , Liu Lijun , Huang Xinming
Published: May 2014

For the seed‐assisted casting process for silicon ingots, different partition blocks were designed in the directional solidification (DS) furnaces to preserve the seed crystals and optimize the thermal field in the hot‐zone. A transient global model was established to investigate the effects of different partition blocks during the solidification process. The simulation results showed that the partition blocks can significantly influence the temperature distributions and the melt flow fields. From the designed partition blocks, the movable partition block was more favorable for the seed‐assisted DS process. A suitable temperature gradient and a flat seed‐melt (s‐m) interface were obtained, which facilitated the preservation of seed crystals effectively, and an optimized crystal‐melt (c‐m) interface was achieved as well. One of the designs of the movable partition blocks was implemented in quasi‐mono crystalline silicon casting experiments and it has been confirmed that the designed movable partition block was helpful for the improvement of the single crystal area.
PD‐L1 gene polymorphisms and low serum level of PD‐L1 protein are associated to type 1 diabetes in Chile
Authors: Pizarro Carolina , García‐Díaz Diego F. , Codner Ethel , Salas‐Pérez Francisca , Carrasco Elena , Pérez‐Bravo Francisco
Published: May 2014

Introduction

Type 1 diabetes (T1D) has a complex etiology in which genetic and environmental factors are involved, whose interactions have not yet been completely clarified. In this context, the role in PD‐1 pathway and its ligands 1 and 2 (PD‐L1 and PD‐L2) have been proposed as candidates in several autoimmune diseases. The aim of this work was to determine the allele and haplotype frequency of six gene polymorphisms of PD‐ligands (PD‐L1 and PD‐L2) in Chilean T1D patients and their effect on serum levels of PD‐L1 and autoantibody profile (GAD65 and IA2).

Methods

This study cohort comprised 205 T1D patients and 205 normal children. We performed genotypic analysis of PD‐L1 and PD‐L2 genes by TaqMan method. Determination of anti‐GAD65 and anti‐IA‐2 autoantibodies was performed by ELISA. The PD‐L1 serum levels were measured.

Results

The allelic distribution of PD‐L1 variants (rs2297137 and rs4143815) showed differences between T1D patients and controls (p = 0.035 and p = 0.022, respectively). No differences were detected among the PD‐L2 polymorphisms, and only the rs16923189 showed genetic variation. T1D patients showed decreased serum levels of PD‐L1 compared to controls: 1.42 [0.23–7.45] ng/mL versus 3.35 [0.49–5.89] ng/mL (p < 0.025). In addition, the CGG haplotype in PD‐L1 associated with T1D (constructed from rs822342, rs2297137 and rs4143815 polymorphisms) showed an OR = 1.44 [1.08 to 1.93]. Finally, no association of these genetic variants was observed with serum concentrations of PD ligands or auto‐antibody profile, although a correlation between PD‐L1 ligand serum concentration and the age at disease onset was detected.

Conclusion

Two polymorphism of PD‐L1 are presented in different allelic variants between T1D and healthy subjects, also PDL‐1 serum levels are significantly lowered in diabetics patients. Moreover, the age of onset of the disease determine differences between serum ligand levels in diabetics, being lower in younger. These results points to a possible establishment of PDL‐1 as a genetic and biochemical marker for T1D onset, at least in Chilean population. Copyright © 2014 John Wiley & Sons, Ltd.
Heart rate variability and the metabolic syndrome: a systematic review of the literature
Authors: Stuckey Melanie I. , Tulppo Mikko P. , Kiviniemi Antti M. , Petrella Robert J.
Published: May 2014

Background

A number of cross‐sectional studies have examined associations between heart rate variability and metabolic syndrome, but differences in study populations, data collection and analysis methodologies make synthesis difficult. The purpose of this study was to systematically review published primary research examining associations between heart rate variability and metabolic syndrome or its individual risk factors.

Methods

A systematic literature search of PubMed and EMBASE was conducted to identify relevant articles published from January 1999 to December 2012. Studies were included if they examined associations between heart rate variability analysed by standard protocols and metabolic syndrome risk factors according to published definitions. All papers were scored with a modified Downs and Black instrument, and data were extracted.

Results

Fourteen studies were included. Heart rate variability generally was reduced in women with metabolic syndrome compared to those without, while results in men were inconsistent. Time and frequency domain heart rate variability parameters were associated with individual metabolic syndrome risk factors, though sex differences exist. Only two studies considered nonlinear and Poincaré plot heart rate variability parameters, which were reduced in metabolic syndrome.

Conclusions

Heart rate variability is altered differently in men and women with metabolic syndrome. Future studies should follow consistent heart rate variability analysis protocols and metabolic syndrome definitions and include more comprehensive analyses to investigate potential mechanisms. Copyright © 2014 John Wiley & Sons, Ltd.
Are changes in glycaemic control associated with diabetes‐specific quality of life and health status in screen‐detected type 2 diabetes patients? Four‐year follow up of the ADDITION‐Cambridge cohort
Authors: Kuznetsov L. , Long G. H. , Griffin S. J. , Simmons R. K.
Published: May 2014

Background

Interventions that improve HbA1c levels do not necessarily improve health‐related quality of life (QoL). This issue may be particularly relevant in asymptomatic diabetes patients detected earlier in the course of the disease.

Methods

HbA1c, diabetes‐specific QoL (ADDQoL) and health status were measured in 510 screen‐detected diabetes patients from the ADDITION‐Cambridge trial at 1 and 5 years post diagnosis. Multivariable logistic/linear regression was used to quantify the longitudinal association between change in HbA1c from 1 to 5 years and ADDQoL and health status at 5 years, adjusting for age, sex, education and trial group; alcohol consumption, smoking, physical activity, plasma vitamin C, HbA1c, ADDQoL or health status at 1 year, and glucose‐lowering medication at 5 years.

Results

From 1 to 5 years, median HbA1c interquartile range increased from 6.3% (5.9–6.8) to 6.8% (6.4–7.4); the median ADDQoL score and mean health status physical health summary score decreased from ‐0.4 (‐1 to ‐0.08) to ‐0.5 (‐1.08 to ‐0.09) (suggesting an adverse impact of diabetes on QoL) and by ‐0.79 (8.94) points, respectively. Increases in HbA1c were independently associated with reporting a negative impact of diabetes on QoL (OR = 1.38, 95% CI: 1.03 to 1.85) but not with the health status summary scores.

Conclusions

Increases in HbA1c from 1 to 5 years post‐diagnosis were independently associated with increased odds of reporting a negative impact of diabetes on QoL. While our results suggest that efforts to reduce HbA1c do not adversely affect health‐related QoL, large numbers of participants still report a negative impact of diabetes on their QoL 5 years post‐diagnosis. © 2014 The Authors. Diabetes/Metabolism Research and Reviews published by John Wiley & Sons, Ltd.
Urea increases fed‐batch growth and γ‐linolenic acid production of nutritionally valuable Arthrospira (Spirulina) platensis cyanobacterium
Authors: Nascimento Sassano Carlos Eduardo , Gioielli Luiz Antonio , Converti Attilio , de Oliveira Moraes Iracema , Sato Sunao , de Carvalho João Carlos Monteiro
Published: May 2014

In this article we investigate the simultaneous influence of feeding time and amount of urea added as a nitrogen source on the fed‐batch growth and composition of Arthrospira (Spirulina) platensis. Cultivations were performed in 5‐L minitanks at constant temperature (25°C) and light intensity (42 μmol photons/m2s), using exponentially increasing rate of urea addition, and varying the above independent variables in the ranges 9–15 days and 4.6–12.1 mM, respectively. Special emphasis was placed on the content of added high value fatty acids (e.g., γ‐linolenic acid) of concern for the food industry. To this purpose, a 22‐plus star central composite design was employed, and maximum cell concentration, cell productivity, yield of biomass on nitrogen added, protein content and fatty acids profile were evaluated by multiple regression analysis. The highest cell concentration (1759 mg/L) was obtained at feeding time of 14 days and amount of urea per unit reactor volume of 5.8 mM, while the highest contents of γ‐linolenic acid (27.5% of the lipid fraction) and proteins (77.2%) were obtained at 10 and 14 days and 5.8 and 10.8 mM, respectively. The results confirm the possibility of using urea as cheap nitrogen source to culture this nutritionally valuable cyanobacterium.
Stimulation of endogenous cardioblasts by exogenous cell therapy after myocardial infarction
Authors: Malliaras Konstantinos , Ibrahim Ahmed , Tseliou Eleni , Liu Weixin , Sun Baiming , Middleton Ryan C , Seinfeld Jeffrey , Wang Lai , Sharifi Behrooz G , Marbán Eduardo
Published: May 2014

Controversy surrounds the identity, origin, and physiologic role of endogenous cardiomyocyte progenitors in adult mammals. Using an inducible genetic labeling approach to identify small non‐myocyte cells expressing cardiac markers, we find that activated endogenous cardioblasts are rarely evident in the normal adult mouse heart. However, myocardial infarction results in significant cardioblast activation at the site of injury. Genetically labeled isolated cardioblasts express cardiac transcription factors and sarcomeric proteins, exhibit spontaneous contractions, and form mature cardiomyocytes in vivo after injection into unlabeled recipient hearts. The activated cardioblasts do not arise from hematogenous seeding, cardiomyocyte dedifferentiation, or mere expansion of a preformed progenitor pool. Cell therapy with cardiosphere‐derived cells amplifies innate cardioblast‐mediated tissue regeneration, in part through the secretion of stromal cell‐derived factor 1 by transplanted cells. Thus, stimulation of endogenous cardioblasts by exogenous cells mediates therapeutic regeneration of injured myocardium.
Damping systems that are effective over a wide range of displacement amplitudes using metallic yielding component and viscoelastic damper in series
Authors: Yamamoto Masashi , Sone Takayuki
Published: May 2014

A damper system that absorbs energy over a wide range of displacement amplitudes during building vibration was proposed. This system uses a serial connection of a metallic yielding component and viscoelastic damper with a displacement limit mechanism. Three types of the system were developed and tested: a diagonal bracing type, inverted V bracing type, and wall type. The test results showed that all these systems have damping ratios higher than 8% at small vibration amplitudes on the order of 0.1 mm. For a large vibration, a displacement limit mechanism with two pins limited the displacement of the viscoelastic damper as designed. Analytical simulations established that the system reduced the acceleration and the story drift to 60–70% and 80%, respectively, during a small earthquake compared with a conventional metallic yielding damper system. Furthermore, it showed an equivalent control performance during a severe earthquake. The damper system requires that a clearance be maintained for the displacement limit mechanism. However, this may be lost through construction error, residual displacement after an earthquake, and temperature effects. The changes in the clearance due to these effects were discussed. Copyright © 2014 John Wiley & Sons, Ltd.
The influence of landscape connectivity and landslide dynamics upon channel adjustments and sediment flux in the Liwu Basin, Taiwan
Authors: Kuo Cheng‐Wei , Brierley Gary
Published: May 2014

Catchment‐scale analyzes of spatial and temporal variability in landscape connectivity are critical considerations in appraisals of landscape evolution and disaster mitigation in tectonically active mountain belts such as Taiwan. This study uses historical aerial photographs, flow discharge and seismic data to analyze landslide changes and channel adjustments over a 30 year period in the Liwu Basin. Recurrent earthquakes and typhoon events trigger frequent landslide activity, channel adjustment and sediment reworking in this system. Spatial variability in magnitude–frequency relations of hillslope‐valley floor (lateral) and upstream–downstream (longitudinal) connectivity during the study period are shown to reflect annual reworking in source and accumulation zones, while partly‐confined valleys in the mid‐catchment area trap sediment behind landslide‐induced dams that are formed and breached on an approximately decadal basis. This promotes partial longitudinal connectivity in these areas. Landscape responses to disturbance events were especially pronounced following combinations of seismic and typhoon events prior to the 1998 and 2005 images. Although single high magnitude events and series of moderate events affect patterns of landscape connectivity in the Liwu Basin, residence times for sediment storage are very short in this highly‐connected river system, where confined valley settings extend virtually to the coast. Copyright © 2014 John Wiley & Sons, Ltd.
Is the connectivity function a good indicator of soil infiltrability distribution and runoff flow dimension?
Authors: Harel Marie‐Alice , Mouche Emmanuel
Published: May 2014

Among the studies on runoff connectivity of soils with heterogeneous properties, the need to understand the relationships between soil heterogeneity and the associated runoff organization and amount is frequently mentioned. In this study, we simulate the stationary runoff–runon process on bi‐dimensional (2D) flat slopes for five infiltrability distributions, one of them correlated, as a function of rainfall intensity and flow dimension. We define flow dimension by 1 + ε, where ε is the outflow fraction transferred from one pixel to each of the two lateral downslope pixels. Our aim is to assess the effect of ε and soil heterogeneity on the connectivity function compared to the mean runoff flow rate, the wet area and the number of runoff patterns. The analysis of connectivity is carried within the percolation framework. The results show that the integral connectivity scale is more sensitive to the flow dimension and soil heterogeneity compared to the other variables. The wet area fraction does not depend on ε. Unlike previous studies, we find that increased runoff production is not necessarily related to increased connectivity. The use of the connectivity function within the percolation framework appears to be a valuable method for assessing the impact of soil heterogeneity and flow dimension on the runoff organization during a rainfall event. Copyright © 2014 John Wiley & Sons, Ltd.
Geology, fluid inclusion and age constraints on the genesis of the Sarekuobu gold deposit in Altay, NW China
Authors: Zhang Li , Chen Hua‐Yong , Zheng Yi , Qin Ya‐Jing , Li Deng‐Feng
Published: May 2014

The Sarekuobu gold deposit was discovered in the 1990s and is located in the Kelan Basin on the southern margin of the Chinese Altay Orogen. Orebodies are hosted in the Early Devonian metamorphosed volcanic‐sedimentary sequence and controlled by the NW‐trending Abagong Fault. Mineralization can be divided into early, middle and late stages, characterized by quartz–pyrite, polymetallic quartz–sulphides and carbonate–quartz, respectively. Four types of fluid inclusions were identified in quartz veins, i.e. pure CO2 (PC‐type), CO2–H2O (C‐type), aqueous (W‐type) and daughter mineral‐bearing inclusions (S‐type). Hydrothermal fluids related to the mineralization are composed of CO2–H2O–NaCl ± CH4 ± N2 fluids with Th values of 236–374 °C and salinities of 4.8–15.0 wt.% NaCl eqv. (in general 8.0–15.0 wt.% NaCl eqv.), combined with trapping pressures of 90–330 MPa, suggesting that the mineralization resulted from a metamorphic fluid system. One biotite sample from the polymetallic quartz lodes yields a 40Ar/39Ar isotopic plateau age of 213.5 ± 2.3 Ma, marking the time of mineralization as Triassic. This mineralization age is broadly comparable with the mineralization age reported from the Tiemurt Pb–Zn deposit and Wulasigou Cu deposit located near the Sarekuobu gold deposit, indicating that the deposit was possibly related to the Permian–Triassic continental collision at the southern margin of the Altay Orogen. Our results show that the Sarekuobu gold deposit is not syngenetic, but an epigenetic orogenic gold deposit. Copyright © 2014 John Wiley & Sons, Ltd.
Inhibition of Hypoxia Inducible Factor 1α by siRNA‐Induced Apoptosis in Human Retinoblastoma Cells
Authors: Gao Yu , Jing Ming , Ge Rongrong , Zhou Zhe , Sun Yan
Published: May 2014

Hypoxia, which activates the hypoxia inducible factor 1α (HIF‐1α), is an essential feature of retinoblastoma (RB) and contributes to poor prognosis and resistance to conventional therapy. In this study, the effect of HIF‐1α knockdown by small interfering RNA (siRNA) on cell proliferation, apoptosis, and apoptotic pathways of human Y‐79 RB cells was first investigated. Exposure to hypoxia induced the increased expression of HIF‐1α both in mRNA and protein levels. Then, knockdown of HIF‐1α by siRNAHIF‐1α resulted in inhibition of cell proliferation and induced cell apoptosis in human Y‐79 RB cells under both normoxic and hypoxic conditions, with hypoxic conditions being more sensitive. Furthermore, knockdown of HIF‐1α could enhance hypoxia‐induced slight increase of Bax/Bcl‐2 ratio and activate caspase‐9 and caspase‐3. These results together indicated that suppression of HIF‐1α expression may be a promising strategy for the treatment of human RB in the future.
Postural response to vibration of triceps surae, but not quadriceps muscles, differs between people with and without knee osteoarthritis
Authors: Shanahan Camille J. , Wrigley Tim V. , Farrell Michael J. , Bennell Kim L. , Hodges Paul W.
Published: May 2014

Although proprioceptive impairments are reported in knee osteoarthritis (OA), there has been little investigation of the underlying causes. Muscle spindles make an important contribution to proprioception. This study investigated whether function of quadriceps, triceps surae, and tibialis anterior muscle spindles is altered in individuals with knee OA. Thirty individuals with knee OA (17 females, 66 ± 7 [mean ± SD] years) and 30 healthy asymptomatic controls (17 females, 65 ± 8 years) stood comfortably and blindfolded on a force plate. Mechanical vibration (60 Hz) was applied bilaterally over the quadriceps, triceps surae, or tibialis anterior muscles for the middle 15 s (Vibration) of a 45 s trial (preceded and followed by 15 s Baseline and Recovery periods). Two trials were recorded for each muscle site. Mean anterior–posterior displacement of centre of pressure was analysed. Although there were no differences between groups for trials with vibration applied to the quandriceps or tibialis anterior, participants with knee OA were initially perturbed more by triceps surae vibration and accommodated less to repeated exposure than controls. This indicates that people with knee OA have less potential to detect or compensate for disturbed input to triceps surae, possibly due to an inability to compensate using muscles spindles in the quadriceps muscle. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:989–996, 2014.
Chain‐Length‐Dependent Termination of Vinyl Acetate and Vinyl Pivalate Bulk Homopolymerizations Studied by SP‐PLP‐EPR
Authors: Kattner Hendrik , Buback Michael
Published: May 2014

Bulk homopolymerizations of vinyl acetate and vinyl pivalate are studied by EPR experiments between −65 °C and 60 °C with dicumyl peroxide acting as the photoinitiator. No mid‐chain radicals are seen, which demonstrates that backbiting plays no role. The chain‐length dependence of the termination rate coefficients measured up to 13% monomer conversion is adequately represented by the composite model. The power‐law exponents αs and αl for short‐chain and long‐chain radicals are: αs(VAc) = 0.57 ± 0.05, αs(VPi) = 0.67 ± 0.15, αl(VAc) = 0.16 ± 0.07, and αl(VPi) = 0.16 ± 0.07. The crossover chain lengths differ largely: ic(VAc) = 20 ± 10 and ic(VPi) = 110 ± 30. The rate coefficient for termination of two radicals of chain length unity, , which is the fourth composite‐model parameter, depends on temperature, as does the monomer fluidity.

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Algorithmic randomness over general spaces
Authors: Miyabe Kenshi
Published: May 2014

The study of Martin‐Löf randomness on a computable metric space with a computable measure has seen much progress recently. In this paper we study Martin‐Löf randomness on a more general space, that is, a computable topological space with a computable measure. On such a space, Martin‐Löf randomness may not be a natural notion because there is no universal test, and Martin‐Löf randomness and complexity randomness (defined in this paper) do not coincide in general. We show that SCT3 is a sufficient condition for the existence and coincidence, and study how much we can weaken this condition.
Algebraic functions in quasiprimal algebras
Authors: Campercholi Miguel , Vaggione Diego
Published: May 2014

A function is algebraic on an algebra if it can be implicitly defined by a system of equations on . In this note we give a semantic characterization for algebraic functions on quasiprimal algebras. This characterization is applied to obtain necessary and sufficient conditions for a quasiprimal algebra to have every one of its algebraic functions be a term function. We also apply our results to particular algebras such as finite fields and monadic algebras.
From Bolzano‐Weierstraß to Arzelà‐Ascoli
Authors: Kreuzer Alexander P.
Published: May 2014

We show how one can obtain solutions to the Arzelà‐Ascoli theorem using suitable applications of the Bolzano‐Weierstraß principle. With this, we can apply the results from and obtain a classification of the strength of instances of the Arzelà‐Ascoli theorem and a variant of it. Let be the statement that each equicontinuous sequence of functions contains a subsequence that converges uniformly with the rate and let be the statement that each such sequence contains a subsequence which converges uniformly but possibly without any rate. We show that is instance‐wise equivalent, over , to the Bolzano‐Weierstraß principle and that is instance‐wise equivalent, over , to , and thus to the strong cohesive principle (). Moreover, we show that over the principles , and are equivalent.
On the strength of marriage theorems and uniformity
Authors: Fujiwara Makoto , Higuchi Kojiro , Kihara Takayuki
Published: May 2014

Kierstead showed that every computable marriage problem has a computable matching under the assumption of computable expanding Hall condition and computable local finiteness for boys and girls. The strength of the marriage theorem reaches or if computable expanding Hall condition or computable local finiteness for girls is weakened. In contrast, the provability of the marriage theorem is maintained in even if local finiteness for boys is completely removed. Using these conditions, we classify the strength of variants of marriage theorems in the context of reverse mathematics. Furthermore, we introduce another condition that also makes the marriage theorem provable in , and investigate the sequential and Weihrauch strength of marriage theorems under that condition.
Definably extending partial orders in totally ordered structures
Authors: Ramakrishnan Janak , Steinhorn Charles
Published: May 2014

We show, for various classes of totally ordered structures , including o‐minimal and weakly o‐minimal structures, that every definable partial order on a subset of extends definably in  to a total order. This extends the result proved in for and o‐minimal.
Around independence and domination in metric abstract elementary classes: assuming uniqueness of limit models
Authors: Villaveces Andrés , Zambrano Pedro
Published: May 2014

We study notions of independence appropriate for a stability theory of metric abstract elementary classes (for short, MAECs). We build on previous notions used in the discrete case, and adapt definitions to the metric case. In particular, we study notions that behave well under superstability‐like assumptions. Also, under uniqueness of limit models, we study domination, orthogonality and parallelism of Galois types in MAECs.