bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of a novel fibrous antibacterial fiber with organophorsphor functional groups
Authors: Chang Li , Zhang Xiaozhuan , Shi Xibao , Zhao Liang , Liu Xuan Ming
Published: May 2014

A novel antibacterial fiber named ethyltriphenylphosphonium bromide‐polyacrylonitrile fiber (ETPB‐PANF) was synthesized by chemical modification of PANF reacted with ETPB. The PANF was first immersed in NaOH solution to get Na‐PANF with COONa groups. Na‐PANF was then reacted with ETPB to get the final fiber. During the process of synthesis, this article investigated on the initial concentration of ETPB, the contact time, the reaction temperature, and the pH of the solution that may have effect on the properties of ETPB‐PANF. ETPB‐PANF was characterized by Fourier transform infrared spectroscopy, thermo gravimetric analyzer, scanning electron microscope, and X‐ray photoelectron spectroscopy, and the releasing amount of ETPB from ETPB‐PANF was examined by inductively coupled plasma atomic emission spectrometry. The antibacterial activity of ETPB‐PANF was examined against Escherichia coli and Staphylococci aureus by improved shake flask method in sterile saline. The results showed that organophorsphor functional groups have been successfully grafted on PANF, and ETPB‐PANF showed good antibacterial abilities for E. coli and S. aureus. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40935.
Nonisothermal crystallization behaviors of biodegradable double crystalline poly(butylene succinate)‐poly(ethylene glycol) multiblock copolymers
Authors: Huang Cai‐Li , Zeng Jian‐Bing , Jiao Ling , Yang Ke‐Ke
Published: May 2014

Nonisothermal crystallization behaviors of both poly(butylene succinate) (PBS) and poly(ethylene glycol) (PEG) segments within PBS‐PEG (PBSEG) multiblock copolymers were investigated by differential scanning calorimetry (DSC). The nonisothermal crystallization kinetics of both PBS and PEG segments were analyzed by Avrami, Ozawa, and Mo methods. The results showed that both of Avrami and Mo methods were successful to describe the nonisothermal crystallization kinetics of PBS and PEG segments. The results of crystallization kinetics indicated that the crystallization rate of PBS segment decreased with PBS segment content and/or LPBS, while that of PEG segment decreased with Mn,PEG or FPEG. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40940.
Thermoresponsive hydrogels from BSA esterified with low molecular weight PEG
Authors: Wang Kai , Buschle‐Diller Gisela , Wu Yonnie
Published: May 2014

Bovine serum albumin (BSA) and low molecular weight polyethylene glycol (PEG) were reacted in a single‐step reaction to synthesize translucent hydrogels with a sol–gel transition at temperatures between 37 and 40°C. Gelation occurred by aggregation of smaller assemblies of BSA–PEG precursors within minutes. The sol–gel transition concentration depended on the molecular weight of PEG only at temperatures below 35°C; above 45°C phase separation occurred and a precipitate formed. Microscopic examination showed the porous structure of the gels. At a fairly low grafting ratio, BSA preserved its native secondary and tertiary structure and maintained its capability for binding and enclosing small molecules. Drug delivery was assessed by a discontinuous method in vitro using 5‐fluorouracil. Degradation tests with trypsin confirmed that the hydrogels were biodegradable. This novel material holds promise for biomedical applications as potentially injectable drug delivery vehicle. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40946.
Magnetic Susceptibility Detection of Small Protohistoric Sites in the Raganello Basin, Calabria (Italy)
Authors: Van leusen P. M. , Kattenberg A. , Armstrong K.
Published: May 2014

This paper presents pilot geophysical investigations carried out in 2005–2006 by the Groningen Institute of Archaeology in northern Calabria, Italy. The aim of this work was to find out if and how surface magnetic susceptibility (MS) measurements might be of use to correct significant visibility biases in the results of earlier large‐scale systematic and intensive field‐walking, in particular for unobtrusive rural protohistoric sites. It was found that MS yields encouraging results under specific geopedological conditions, but that a better understanding of post‐depositional site histories and large‐scale geomorphology‐driven MS variations is needed before an effective MS‐based detection protocol in support of large‐scale field‐walking can be developed; follow‐on studies are now being conducted by the authors to this end. Copyright © 2014 John Wiley & Sons, Ltd.
Using content and network analysis to understand the social support exchange patterns and user behaviors of an online smoking cessation intervention program
Authors: Zhang Mi , Yang Christopher C.
Published: May 2014

Informational support and nurturant support are two basic types of social support offered in online health communities. This study identifies types of social support in the QuitStop forum and brings insights to exchange patterns of social support and user behaviors with content analysis and social network analysis. Motivated by user information behavior, this study defines two patterns to describe social support exchange: initiated support exchange and invited support exchange. It is found that users with a longer quitting time tend to actively give initiated support, and recent quitters with a shorter abstinent time are likely to seek and receive invited support. This study also finds that support givers of informational support quit longer ago than support givers of nurturant support, and support receivers of informational support quit more recently than support receivers of nurturant support. Usually, informational support is offered by users at late quit stages to users at early quit stages. Nurturant support is also exchanged among users within the same quit stage. These findings help us understand how health consumers are supporting each other and reveal new capabilities of online intervention programs that can be designed to offer social support in a timely and effective manner.
Distributed Robust Consensus of a Class of Lipschitz Nonlinear Multi‐agent Systems with Matching Uncertainties
Authors: Li Zhongkui , Zhao Yu , Duan Zhisheng
Published: May 2014

This paper considers the distributed robust consensus problem of a class of multi‐agent systems with Lipschitz nonlinear dynamics and subject to different matching uncertainties. Due to the existence of nonidentical uncertainties, the multi‐agent systems discussed in this paper are essentially heterogeneous. For the case where the communication graph is undirected and connected, based on the local state information of neighboring agents, distributed continuous static and adaptive consensus protocols are designed, under which the consensus error is uniformly ultimately bounded and exponentially converges to a small adjustable residual set. Note that the proposed distributed adaptive consensus protocol relies on neither the eigenvalues of the Laplacian matrix nor the upper bounds of the uncertainties. The case where there exists a leader whose control input is unknown and bounded is further studied.
Synchronization for Time‐Delayed Coupling Complex Dynamic Networks with Different Dimensional Nodes Via Decentralized Dynamic Compensation Controllers
Authors: Zhang Lili , Wang Yinhe , Wang Qinruo , Zhang Siying
Published: May 2014

The objective of this paper is to investigate the synchronization for nonlinear time‐delayed coupling complex dynamic networks with different dimensional nodes through the use of decentralized dynamic compensation controllers. We propose a nonlinear time‐delayed coupling complex dynamic network model with similar nonlinear nodes, whose dimensions admit differences. For this kind of network model, based on Barbalat's lemma, decentralized dynamic compensation controllers are designed for the state synchronization of the coupled nodes under some mathematical conditions. In addition, the synchronization manifold is defined as an invariant manifold, which is regarded as the generalized case of the networks with the same node dynamics. Finally, numerical examples with chaotic and hyperchaotic nodes are presented to verify the effectiveness of our theoretical results.
Biorefinery of microalgae – opportunities and constraints for different production scenarios
Authors: Hariskos Ioanna , Posten Clemens
Published: May 2014

In order to design economically feasible production processes it is necessary, as part of the biorefinery concept, to valorize all constituents of the microalgal biomass. Such an approach requires appropriate biorefinery side‐process strategies to be adapted to production of the primary product. These strategies are particularly valid for microalgae, since the composition and amount of residual biomass can vary significantly depending on cell stoichiometry and cultivation techniques. This review investigates opportunities and constraints for biorefinery concepts in production scenarios for four different products from microalgae with different market volumes, including high‐ and medium‐value products, whole cells and biodiesel. Approaches to close material and energy balances, as well as to adapt the biorefinery according to biological potential, process routes, and market needs are presented, which will further contribute to making the biorefinery concept a success.
Glossoscolex paulistus extracellular hemoglobin (HbGp) oligomeric dissociation upon interaction with sodium dodecyl sulfate: Isothermal titration calorimetry (ITC)
Authors: Alves Fernanda Rosa , Carvalho Francisco Adriano O. , Carvalho José Wilson P. , Tabak Marcel
Published: May 2014

Annelid erythrocruorins are respiratory proteins with high cooperativity and low autoxidation rates. The giant extracellular hemoglobin of the earthworm, Glossoscolex paulistus (HbGp), has a molecular mass of 3.6 MDa. In this work, isothermal titration calorimetry (ITC), together with DLS and fluorescence emission have been used to investigate the interaction of SDS with the HbGp in the oxy‐form, at pH 7.0. Our ITC and DLS results show that addition of SDS induces oxy‐HbGp oligomeric dissociation, while a small amount of protein aggregation is observed only by DLS. Moreover, the oligomeric dissociation process is favored at lower protein concentrations. The temperature effect does not influence significantly the interaction of SDS with the hemoglobin, due to the similarities presented by the critical aggregation concentration (cac) and critical micelle concentration (cmc′) for the mixtures. The increase of oxy‐HbGp concentration leads to a slight variation of the cac values for the SDS‐oxy‐HbGp mixture, attributed mainly to the noncooperative electrostatic binding of surfactant to protein. However, the cmc′ values increase considerably, associated to a more cooperative hydrophobic binding. Complementary pyrene fluorescence emission studies show formation of pre‐micellar structures of the mixture already at lower SDS concentrations. This study opens the possibility of the evaluation of the surfactant effect on the hemoglobin stability by ITC, which is made for the first time with this extracellular hemoglobin. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 1065–1076, 2014.
Influence of substituents on conformational preferences of helix foldamers of γ‐dipeptides
Authors: Kee Kang Young , Yoo In Kee
Published: May 2014

Conformational preferences of 9‐ and 14‐helix foldamers have been studied for γ‐dipeptides of 2‐aminocyclohexylacetic acid (γAc6a) residues such as Ac‐(γAc6a)2‐NHMe (1), Ac‐(Cα‐Et‐γAc6a)2‐NHMe (2), Ac‐(γAc6a)2‐NHBn (3), and Ac‐(Cα‐Et‐γAc6a)2‐NHBn (4) at the M06‐2X/cc‐pVTZ//M06‐2X/6‐31 + G(d) level of theory to explore the influence of substituents on their conformational preferences. In the gas phase, the 9‐helix foldamer H9 and 14‐helix foldamer H14‐z are found to be most preferred for dipeptides 2 and 4, respectively, as for dipeptides 1 and 3, which indicates no remarkable influence of the Cα‐ethyl substitution on conformational preferences. The benzyl substitution at the C‐terminal end lead H14‐z to be the most preferred conformer for dipeptides 3 and 4, whereas it is H9 for dipeptides 1 and 2, which can be ascribed to the favored CH···π interactions between the cyclohexyl group of the first residue and the C‐terminal benzyl group. There are only marginal changes in backbone structures and the distances and angles of H‐bonds for all local minima by Cα‐ethyl and/or benzyl substitutions. Although vibrational frequencies and intensities of the dipeptide 4 calculated at both M06‐2X/6‐31 + G(d) and M05‐2X/6‐31 + G(d) levels of theory are consistent with observed results in the gas phase, H14‐z is predicted to be most preferred by ΔG only at the former level of theory. Hydration did not bring the significant changes in backbone structures of helix foldamers for both dipeptide 1 and 4. It is expected that the different substitutions at the C‐terminal end lead to the different helix foldamers, which may increase the resistance of helical structures to proteolysis and provide the more surface to the helical structures suitable for molecular recognition. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 1077–1087, 2014.
A new method for generating high purity motoneurons from mouse embryonic stem cells
Authors: McCreedy Dylan A. , Brown Chelsea R. , Butts Jessica C. , Xu Hao , Huettner James E. , Sakiyama‐Elbert Shelly E.
Published: May 2014

A common problem with using embryonic stem (ES) cells as a source for analysis of gene expression, drug toxicity, or functional characterization studies is the heterogeneity that results from many differentiation protocols. The ability to generate large numbers of high purity differentiated cells from pluripotent stem cells could greatly enhance their utility for in vitro characterization studies and transplantation in pre‐clinical injury models. Population heterogeneity is particularly troublesome for post‐mitotic neurons, including motoneurons, because they do not proliferate and are quickly diluted in culture by proliferative phenotypes, such as glia. Studies of motoneuron biology and disease, in particular amyotrophic lateral sclerosis, can benefit from high purity motoneuron cultures. In this study, we engineered a transgenic‐ES cell line where highly conserved enhancer elements for the motoneuron transcription factor Hb9 were used to drive puromycin N‐acetyltransferase expression in ES cell‐derived motoneurons. Antibiotic selection with puromycin was then used to obtain high purity motoneuron cultures following differentiation of mouse ES cells. Purity was maintained during maturation allowing the production of consistent, uniform populations of cholinergic ES cell‐derived motoneurons. Appropriate functional properties of purified motoneurons were verified by acetylcholinesterase activity and electrophysiology. Antibiotic selection, therefore, can provide an inexpensive alternative to current methods for isolating ES cell‐derived motoneurons at high purity that does not require specialized laboratory equipment and provides a unique platform for studies in motoneuron development and degeneration. Biotechnol. Bioeng. 2014;111: 2041–2055. © 2014 Wiley Periodicals, Inc.
Environmental Responsibility and Firm Performance: The Application of an Environmental, Social and Governance Model
Authors: Lee Ki‐Hoon , Cin Beom Cheol , Lee Eui Young
Published: May 2014

This paper investigates the way in which environmental responsibility impacts on corporate financial performance, measured by return on equity (ROE) and return on assets (ROA). Using a sample of Korean firms covering the period 2011–2012, and employing two different test methods, namely the OLS and 2SLS methods, we show that the relationships between environmental responsibility performance and firms’ ROE and ROA are positive and statistically significant. However, we show that research and development (R&D) intensity (expenditure) does not affect either environmental responsibility or corporate financial performance. The results of this analysis encourage further empirical analysis of the industries, as well as the use of more than one estimation method to determine environmental responsibility and corporate financial performance within firms. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment
Do Customers Affect the Value Relevance of Sustainability Reporting? Empirical Evidence on Stakeholder Interdependence
Authors: Goettsche Max , Steindl Tobias , Gietl Simon
Published: May 2014

In spite of the strategic importance of sustainability reporting in current business practice and the resulting increase in research on its value relevance, studies accounting for stakeholder interdependence are scarce. On the basis of the instrumental stakeholder theory, we investigate whether customers have an impact on the value relevance of sustainability reporting. Using a sample of US listed firms, we show that the value relevance of sustainability reporting is affected by customer profile differences, thereby confirming customer–shareholder interdependence. However, customer profile effects are only predominant if firms' profitability levels are low and disappear as profitability increases. Overall, our findings provide a more nuanced understanding of the value relevance of sustainability reporting. Therefore, we offer managers fine‐grained guidance for value relevant sustainability reporting. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment
Towards a data‐driven approach to scenario generation for serious games
Authors: Luo Linbo , Yin Haiyan , Cai Wentong , Lees Michael , Othman Nasri Bin , Zhou and Suiping
Published: May 2014

Serious games have recently shown great potential to be adopted in many applications, such as training and education. However, one critical challenge in developing serious games is the authoring of a large set of scenarios for different training objectives. In this paper, we propose a data‐driven approach to automatically generate scenarios for serious games. Compared with other scenario generation methods, our approach leverages on the simulated player performance data to construct the scenario evaluation function for scenario generation. To collect the player performance data, an artificial intelligence (AI) player model is designed to imitate how a human player behaves when playing scenarios. The AI players are used to replace human players for data collection. The experiment results show that our data‐driven approach provides good prediction accuracy on scenario's training intensities. It also outperforms our previous heuristic‐based approach in its capability of generating scenarios that match closer to specified target player performance.Copyright © 2014 John Wiley & Sons, Ltd.
Controllable Loading of Noble Metal Nanoparticles on Multiwalled Carbon Nanotubes/Fe3O4 through an In Situ Galvanic Replacement Reaction for High‐Performance Catalysis
Authors: Yang Shu‐Liang , Cao Chang‐Yan , Wei Fang‐Fang , Huang Pei‐Pei , Sun Yong‐Bin , Song Wei‐Guo
Published: May 2014

Nobel metal nanoparticle loaded carbon nanotube (CNT) composites have wide applications in heterogeneous catalysis, and the catalytic properties are largely controlled by the size, composition, and dispersion state of the noble metal nanoparticles. However, the chemically inert feature of CNTs makes it difficult to directly disperse noble metal nanoparticles in a uniform manner. In this work, by an in situ galvanic replacement reaction between Cu nanoparticles and noble metal ions, a simple and efficient strategy was developed to produce magnetic multiwalled (MW) CNTs–Fe3O4 supported noble metal nanoparticles. The MWCNTs–Fe3O4–Pd showed impressive activity in the carbonylative Sonogashira coupling reaction and in the catalytic hydrodegradation of methylene blue.
CH Bond Activation with Triel Metals: Indium and Gallium Zwitterions through Internal Hydride Abstraction in Rigid Salan Ligands
Authors: Maudoux Nicolas , Fang Jian , Roisnel Thierry , Dorcet Vincent , Maron Laurent , Carpentier Jean‐François , Sarazin Yann
Published: May 2014

The hydropyrimidine salan (salan=N,N′‐dimethyl‐N,N′‐bis[(2‐hydroxyphenyl)methylene]‐1,2‐diaminoethane) proteo‐ligands with a rigid backbone {ON^(CH2)^NO}H2 react with M(CH2SiMe3)3 (M=Ga, In) to yield the zwitterions {ON^(CH+)^NO}M−(CH2SiMe3)2 (M=Ga, 2; In, 3) by abstraction of a hydride from the ligand backbone followed by elimination of dihydrogen. By contrast, with Al2Me6, the neutral‐at‐metal bimetallic complex [{ON^(CH2)^NO}AlMe]2 ([1]2) is obtained quantitatively. The formation of indium zwitterions is also observed with sterically more encumbered ligands containing o‐Me substituents on the phenolic rings, or an N (CHPh) N moiety in the heterocyclic core. Overall, the ease of CH bond activation follows the order Al≪Ga<In. Experimental data based on model complexes, XRD studies, and 2H NMR spectroscopy show that the formation of the Ga/In zwitterion involves rapid release of SiMe4 followed by evolution of H2, and suggest the formation of a transient metal‐hydride species. DFT calculations indicate that the systems {ON^(CH2)^NO}H2+M(CH2SiMe3)3 (M=Al, Ga, In) all initially lead to the formation of the neutral monophenolate dihydrocarbyl species through a single protonolysis. From here, the thermodynamic product, the model neutral‐at‐metal complex 1, is formed in the case of aluminum after a second protonolysis. On the other hand, lower activation energy pathways lead to the generation of zwitterionic complexes 2 and 3 in the cases of gallium and indium, and the formation of these zwitterions obeys a strict kinetic control; the computations suggest that, as inferred from the experimental data, the reaction proceeds through an instable metal‐hydride species, which could not be isolated synthetically.
Cellular Accumulation, Lipophilicity and Photocytotoxicity of Diazido Platinum(IV) Anticancer Complexes
Authors: Pizarro Ana M. , McQuitty Ruth J. , Mackay Fiona S. , Zhao Yao , Woods Julie A. , Sadler Peter J.
Published: May 2014

The lipophilicity of ten photoactivatable platinum(IV) diazido prodrugs of formula trans,trans,trans‐[Pt(N3)2(OH)2(R)(R′)] (where R and R′ are NH3, methylamine, ethylamine, pyridine, 2‐picoline, 3‐picoline or thiazole) has been determined by their retention times on reversed‐phase HPLC. The lipophilicity of the complexes shows a linear dependence on the lipophilicity (partition coefficient) of the ligands. Accumulation of platinum in A2780 human ovarian cancer cells after one hour drug exposure in the dark is compared with their cytotoxic potency on activation with UVA (365 nm) and to their lipophilicity. No correlation between lipophilicity and intracellular accumulation of platinum was observed, perhaps suggesting involvement of active transport and favoured influx of selected structures. Furthermore, no correlation between platinum accumulation and photocytotoxicity was observed in A2780 cancer cells, implying that the type of intracellular damage induced by these complexes plays a key role in their cytotoxic effects.
Coexpression of CD44‐positive/CD133‐positive cancer stem cells and CD204‐positive tumor‐associated macrophages is a predictor of survival in pancreatic ductal adenocarcinoma
Authors: Hou Ya‐Chin , Chao Ying‐Jui , Tung Hui‐Ling , Wang Hao‐Chen , Shan Yan‐Shen
Published: May 2014

BACKGROUND

The interactions between cancer stem cells (CSCs) and tumor‐associated macrophages (TAMs) can promote tumor progression, maintain the CSCs population, and reduce therapeutic effects. The objective of this study was to investigate the coexpression of CSCs and TAMs and its clinical significance in pancreatic ductal adenocarcinoma (PDAC).

METHODS

Ninety‐six patients with PDAC were included in this study. Tissue microarrays were constructed for immunostaining of the CSCs markers CD44 and CD133 and the TAMs marker CD204. Correlations between the expression of CSCs and TAMs markers and clinicopathologic characteristics or disease progression were analyzed.

RESULTS

Expression levels of CD44/CD133 and CD204 were significantly higher in tumor tissues than in normal tissues (P < .0001). The variables associated with survival were high coexpression of CD44/CD133 (P = .000), high expression of CD204 (P = .011), and tumor grade (P = .014). There was a positive correlation between CD44/CD133 and CD204 expression (r = 0.294; P = .004). Survival analysis indicated that high coexpression of CD44/CD133 and CD204 was associated significantly with shorter overall survival (P = .000) and disease‐free survival (P = .003). Multivariate analysis revealed that high CD44/CD133 expression was an independent prognostic factor for disease‐free survival, whereas high CD204 expression was an independent predictor for both overall and disease‐free survival.

CONCLUSIONS

Coexpression of CD44/CD133 and CD204 is a useful survival prediction marker for patients with PDAC. Cancer 2014;120:2766–2777. © The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.
Physical activity and survival of postmenopausal, hormone receptor–positive breast cancer patients: Results of the Tamoxifen Exemestane Adjuvant Multicenter Lifestyle study
Authors: de Glas Nienke A. , Fontein Duveken B. Y. , Bastiaannet Esther , Pijpe Anouk , De Craen Anton J. M. , Liefers Gerrit‐Jan , Nortier Hans J. W. R. , de Haes Hanneke J. C. J. M. , van de Velde Cornelis J. H. , van Leeuwen Flora E.
Published: May 2014

BACKGROUND

Physical activity has been related to improved breast cancer outcomes. Especially in the older breast cancer population, physical activity may be important because old age is associated with comorbidities and decreased physical function. The purpose of this study was to investigate the relation between physical activity and overall survival, breast cancer–specific survival, and recurrence in several age groups of postmenopausal breast cancer patients.

METHODS

The Tamoxifen Exemestane Adjuvant Multinational Lifestyle study was a side study of the Tamoxifen Exemestane Adjuvant Multinational trial and prospectively investigated lifestyle habits of postmenopausal, hormone receptor–positive breast cancer patients. The relations between prediagnosis and postdiagnosis physical activity and overall survival, breast cancer–specific survival, and recurrence‐free survival were assessed with Cox regression and competing risk regression models.

RESULTS

Among 521 patients, high levels of physical activity before and after the diagnosis were associated with better overall survival (the multivariate hazard ratios were 0.50 [95% confidence interval = 0.26‐0.98] and 0.57 (95% confidence interval = 0.26‐1.40] for patients who were very active before and after the diagnosis, respectively, in comparison with inactive patients). This was most evident in patients who were 65 years old or older. Physical activity was not significantly associated with breast cancer–specific survival or the relapse‐free period.

CONCLUSIONS

Overall survival was better for patients who were active before and after the diagnosis. In contrast with previous studies, breast cancer survival and the risk of recurrence were not significantly associated with physical activity. These findings confirmed the need for more studies investigating the use of physical activity to supplement breast cancer treatment in older patients. Cancer 2014;120:2847–2854. © 2014 American Cancer Society.
Electronic and Structural Properties of Highly Aluminum Ion Doped TiO2 Nanoparticles: A Combined Experimental and Theoretical Study
Authors: de los Santos Desireé M. , Aguilar Teresa , Sánchez‐Coronilla Antonio , Navas Javier , Cruz Hernández Norge , Alcántara Rodrigo , Fernández‐Lorenzo Concha , Martín‐Calleja Joaquín
Published: May 2014

This study presents the experimental and theoretical study of highly internally Al‐doped TiO2 nanoparticles. Two synthesis methods were used and detailed characterization was performed. There were differences in the doping and the crystallinity, but the nanoparticles synthesized with the different methods share common features. Anatase to rutile transformation occurred at higher temperatures with Al doping. X‐ray photoelectron spectroscopy showed the generation of oxygen vacancies, which is an interesting feature in photocatalysis. In turn, the band‐gap energy and the valence band did not change appreciably. Periodic density functional calculations were performed to model the experimentally doped structures, the formation of the oxygen vacancies, and the band gap. Calculation of the density of states confirmed the experimental band‐gap energies. The theoretical results confirmed the presence of Ti4+ and Al3+. The charge density study and electron localization function analysis indicated that the inclusion of Al in the anatase structure resulted in a strengthening of the TiO bonds around the vacancy.
Discrete polynary coding immune clonal selection‐based joint subcarrier and power allocation in uplink cognitive OFDM network
Authors: Shang Ronghua , Zhang Kun , Jiao Licheng , Wu Jianshe
Published: May 2014

Cognitive radio has been considered to be one of the main technologies to solve the problem of low spectrum utilization, while the adaptive allocation of network resource is one of the key technologies. A discrete polynary coding immune clonal selection (DPICS)‐based joint subcarrier and power allocation algorithm is proposed to solve the resource allocation problem in uplink cognitive OFDM networks. The novelties of DPICS include the following: A unique coding method is adopted to deal with multi‐value discrete variables. Compared with the traditional methods, the proposed method can acquire the shortest code. Meanwhile, the constraints of the subcarrier allocation are avoided. A heuristic mutation scheme is used to direct the mutation. Subcarriers are reallocated randomly to the secondary users with larger homotactic noise, which has a large probability to produce the optimal solution and improves the searching process. Subcarriers and power are allocated simultaneously, which is different with the traditional biphasic resource allocation algorithms. The biphasic resource allocation algorithms cannot acquire the subcarrier allocation result and power allocation result simultaneously, which makes the final result imprecise. The proposed algorithm avoids this situation and improves the accuracy of the final result. Compared with state‐of‐the‐art algorithms, the proposed algorithm is shown as effective by simulation results. Copyright © 2014 John Wiley & Sons, Ltd.
Models of vocal learning in the songbird: Historical frameworks and the stabilizing critic
Authors: Nick Teresa A.
Published: May 2014

Birdsong is a form of sensorimotor learning that involves a mirror‐like system that activates with both song hearing and production. Early models of song learning, based on behavioral measures, identified key features of vocal plasticity, such as the requirements for memorization of a tutor song and auditory feedback during song practice. The concept of a comparator, which compares the memory of the tutor song to auditory feedback, featured prominently. Later models focused on linking anatomically‐defined neural modules to behavioral concepts, such as the comparator. Exploiting the anatomical modularity of the songbird brain, localized lesions illuminated mechanisms of the neural song system. More recent models have integrated neuronal mechanisms identified in other systems with observations in songbirds. While these models explain multiple aspects of song learning, they must incorporate computational elements based on unknown biological mechanisms to bridge the motor‐to‐sensory delay and/or transform motor signals into the sensory domain. Here, I introduce the stabilizing critic hypothesis, which enables sensorimotor learning by (1) placing a purely sensory comparator afferent of the song system and (2) endowing song system disinhibitory interneuron networks with the capacity both to bridge the motor‐sensory delay through prolonged bursting and to stabilize song segments selectively based on the comparator signal. These proposed networks stabilize an otherwise variable signal generated by both putative mirror neurons and a cortical‐basal ganglia‐thalamic loop. This stabilized signal then temporally converges with a matched premotor signal in the efferent song motor cortex, promoting spike‐timing‐dependent plasticity in the premotor circuitry and behavioral song learning. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 1091–1113, 2015
Characterization of a novel and potentially lethal designer drug (±)‐cis‐para‐methyl‐4‐methylaminorex (4,4'‐DMAR, or ‘Serotoni’)
Authors: Brandt Simon D. , Baumann Michael H. , Partilla John S. , Kavanagh Pierce V. , Power John D. , Talbot Brian , Twamley Brendan , Mahony Olivia , O'Brien John , Elliott Simon P. , Archer Roland P. , Patrick Julian , Singh Kuldip , Dempster Nicola M. , Cosbey Simon H.
Published: May 2014

During the second half of 2013, a total of 26 deaths involving para‐methyl‐4‐methylaminorex (4,4'‐DMAR) were reported to the European Monitoring Centre for Drugs and Drug Addiction. While aminorex and 4‐methylaminorex (4‐MAR) are known psychostimulants, nothing is known about the comparatively new para‐methyl analog. Analytical characterization of two independent samples obtained from online vendors confirmed the presence of the (±)‐cis isomer that also appeared to be associated with at least 18 of the 26 deaths. Extensive characterizations included crystal structure analysis, single, tandem, and high‐resolution mass spectrometry, liquid and gas chromatography, and nuclear magnetic resonance spectroscopy. For the work described here, both the (±)‐cis and (±)‐trans racemates were also synthesized, confirming that the differentiation between these two forms was straight‐forward. Monoamine transporter activity was studied using rat brain synaptosomes which included the comparison with d‐amphetamine, aminorex and (±)‐cis‐4‐MAR. (±)‐cis‐4,4'‐DMAR was a potent, efficacious substrate‐type releaser at transporters for dopamine, norepinephrine and serotonin with EC50 values of 8.6 ± 1.1 nM (DAT), 26.9 ± 5.9 nM (NET) and 18.5 ± 2.8 nM (SERT), respectively. The potency of (±)‐cis‐4,4′‐DMAR at DAT and NET rivalled that of other psychomotor stimulant drugs like d‐amphetamine and aminorex. However, (±)‐cis‐4,4′‐DMAR had much more potent actions at SERT and activity at SERT varied more than 100‐fold across the four drugs. The potent releasing activity of (±)‐cis‐4,4′‐DMAR at all three monoamine transporters predicts a potential for serious side‐effects such as psychotic symptoms, agitation, hyperthermia and cardiovascular stimulation, especially after high‐dose exposure or following combination with other psychostimulants. Copyright © 2014 John Wiley & Sons, Ltd.
High‐resolution food webs based on nitrogen isotopic composition of amino acids
Authors: Chikaraishi Yoshito , Steffan Shawn A. , Ogawa Nanako O. , Ishikawa Naoto F. , Sasaki Yoko , Tsuchiya Masashi , Ohkouchi Naohiko
Published: May 2014

Food webs are known to have myriad trophic links between resource and consumer species. While herbivores have well‐understood trophic tendencies, the difficulties associated with characterizing the trophic positions of higher‐order consumers have remained a major problem in food web ecology. To better understand trophic linkages in food webs, analysis of the stable nitrogen isotopic composition of amino acids has been introduced as a potential means of providing accurate trophic position estimates. In the present study, we employ this method to estimate the trophic positions of 200 free‐roaming organisms, representing 39 species in coastal marine (a stony shore) and 38 species in terrestrial (a fruit farm) environments. Based on the trophic positions from the isotopic composition of amino acids, we are able to resolve the trophic structure of these complex food webs. Our approach reveals a high degree of trophic omnivory (i.e., noninteger trophic positions) among carnivorous species such as marine fish and terrestrial hornets.This information not only clarifies the trophic tendencies of species within their respective communities, but also suggests that trophic omnivory may be common in these webs.
Enhanced suppressor function of TIM‐3+FoxP3+ regulatory T cells
Authors: Gautron Anne‐Sophie , Dominguez‐Villar Margarita , de Marcken Marine , Hafler David A.
Published: May 2014

T‐cell immunoglobulin and mucin domain 3 (TIM‐3) is an Ig‐superfamily member expressed on IFN‐γ‐secreting Th1 and Tc1 cells and was identified as a negative regulator of immune tolerance. TIM‐3 is expressed by a subset of activated CD4+ T cells, and anti‐CD3/anti‐CD28 stimulation increases both the level of expression and the number of TIM‐3+ T cells. In mice, TIM‐3 is constitutively expressed on natural regulatory T (Treg) cells and has been identified as a regulatory molecule of alloimmunity through its ability to modulate CD4+ T‐cell differentiation. Here, we examined TIM‐3 expression on human Treg cells to determine its role in T‐cell suppression. In contrast to mice, TIM‐3 is not expressed on Treg cells ex vivo but is upregulated after activation. While TIM‐3+ Treg cells with increased gene expression of LAG3, CTLA4, and FOXP3 are highly efficient suppressors of effector T (Teff) cells, TIM‐3− Treg cells poorly suppressed Th17 cells as compared with their suppression of Th1 cells; this decreased suppression ability was associated with decreased STAT‐3 expression and phosphorylation and reduced gene expression of IL10, EBI3, GZMB, PRF1, IL1Rα, and CCR6. Thus, our results suggest that TIM‐3 expression on Treg cells identifies a population highly effective in inhibiting pathogenic Th1‐ and Th17‐cell responses.
Protein Based Electrochemical Biosensors for H2O2 Detection Towards Clinical Diagnostics
Authors: Yagati Ajay Kumar , Choi Jeong‐Woo
Published: May 2014

Hydrogen peroxide (H2O2) has a diverse array of physiological and pathological effects within the living cells depending on the extent, timing, and location of its production. Detection of H2O2 is important in food industry, clinical diagnostics, and environmental monitoring at lowest levels. Electrochemical biosensors are efficient as they can analyze biological sample by direct conversion into an electrical signal. Electrochemical sensors based on direct electron transfer (DET) of proteins were developed to achieve fast electron transfer by avoiding free‐diffusing redox species with improved sensitivity. We summarize the prerequisites for the DET of proteins for immobilization on the electrode surfaces with recent developments in development of H2O2 sensors and future prospects in this field.
Investigation of the Antifouling Properties of Phenyl Phosphorylcholine‐Based Modified Gold Surfaces
Authors: Parviz Maryam , Darwish Nadim , Alam Muhammad Tanzirul , Parker Stephen G. , Ciampi Simone , Gooding J. Justin
Published: May 2014

Low impedance, antifouling coatings on gold electrodes based on three new zwitterionic phenyl phosphorylcholine (PPC)‐based layers namely 1) reductively adsorbed PPC diazonium salt, 2) dithiocarbamate PPC SAM and 3) lipoamide PPC SAM (PPC coupled to α‐lipoic acid) were evaluated. The layers were assessed for their ability to limit nonspecific adsorption of proteins to electrode surface with some significant differences observed compared with previously studied PPC diazonium salts reductively adsorbed on glassy carbon. Fluorescence microscopy and electrochemical impedance spectroscopy results suggest that protein adsorption is sensitive to the difference in the structure of the PPC molecules and the charge neutrality of the layers. The lipoamide PPC SAM was shown to be the most effective at resisting nonspecific protein adsorption and this layer was as effective as the ‘gold standard’ of oligo(ethylene oxide) SAMs on gold and PPC diazonium salts reductively adsorbed on glassy carbon.
Multicapillary SDS‐gel electrophoresis for the analysis of fluorescently labeled mAb preparations: A high throughput quality control process for the production of QuantiPlasma and PlasmaScan mAb libraries
Authors: Székely Andrea , Szekrényes Ákos , Kerékgyártó Márta , Balogh Attila , Kádas János , Lázár József , Guttman András , Kurucz István , Takács László
Published: May 2014

Molecular heterogeneity of mAb preparations is the result of various co‐ and post‐translational modifications and to contaminants related to the production process. Changes in molecular composition results in alterations of functional performance, therefore quality control and validation of therapeutic or diagnostic protein products is essential. A special case is the consistent production of mAb libraries (QuantiPlasma™ and PlasmaScan™) for proteome profiling, quality control of which represents a challenge because of high number of mAbs (>1000). Here, we devise a generally applicable multicapillary SDS‐gel electrophoresis process for the analysis of fluorescently labeled mAb preparations for the high throughput quality control of mAbs of the QuantiPlasma™ and PlasmaScan™ libraries.
Effects of dissolved organic matter from a eutrophic lake on the freely dissolved concentrations of emerging organic contaminants
Authors: Xiao Yi-Hua , Huang Qing-Hui , Vähätalo Anssi V. , Li Fei-Peng , Chen Ling
Published: May 2014

The authors studied the effects of dissolved organic matter (DOM) on the bioavailability of bisphenol A (BPA) and chloramphenicol by measuring the freely dissolved concentrations of the contaminants in solutions containing DOM that had been isolated from a mesocosm in a eutrophic lake. The abundance and aromaticity of the chromophoric DOM increased over the 25-d mesocosm experiment. The BPA freely dissolved concentration was 72.3% lower and the chloramphenicol freely dissolved concentration was 56.2% lower using DOM collected on day 25 than using DOM collected on day 1 of the mesocosm experiment. The freely dissolved concentrations negatively correlated with the ultraviolent absorption coefficient at 254 nm and positively correlated with the spectral slope of chromophoric DOM, suggesting that the bioavailability of these emerging organic contaminants depends on the characteristics of the DOM present. The DOM–water partition coefficients (log KOC) for the emerging organic contaminants positively correlated with the aromaticity of the DOM, measured as humic acid–like fluorescent components C1 (excitation/emission = 250[313]/412 nm) and C2 (excitation/emission = 268[379]/456 nm). The authors conclude that the bioavailability of emerging organic contaminants in eutrophic lakes can be affected by changes in the DOM. Environ Toxicol Chem 2014;33:1739–1746. © 2014 SETAC
Intercropping different varieties of radish can increase cadmium accumulation in radish
Authors: Lin Lijin , Liu Qihua , Shi Jun , Sun Jinlong , Liao Ming'an , Mei Luoyin
Published: May 2014

Genetic diversity has supplied effective ways to improve crop yields and disease resistance. Therefore, crop uptake of heavy metals may be reduced by collecting germplasm resources. In the present study, cadmium accumulation and nutrients in radish were investigated by intercropping 3 genotypes (red, green, and white radish) in different combinations. Both pot and field experiments showed that cadmium content in radish was increased by intercropping 2 or 3 genotypes, except when white radish was intercropped with green radish. The biomass of red radish was improved by a mixture of all 3 genotypes, green radish biomass was improved by intercropping with the other 2 varieties, and white radish biomass was improved by intercropping with red radish in both pot and field experiments. The pot experiment indicated that the soil exchangeable cadmium concentration of red radish grown with green radish was lower than that of monoculture, whereas red radish intercropped with white radish was between the respective monocultures; the soil exchangeable cadmium concentrations of green radish grown with white radish and with all 3 genotypes grown together were greater than those of the monocultures. Some intercropping modes also improved potassium and phosphorus contents in the edible parts of radish in the pot experiment. Environ Toxicol Chem 2014; 33:1950–1955. © 2014 SETAC
Antioxidant activity and total phenolic compounds of Dezful sesame cake extracts obtained by classical and ultrasound‐assisted extraction methods
Authors: Esmaeilzadeh Kenari Reza , Mohsenzadeh Fatereh , Amiri Zeinab Raftani
Published: May 2014

Sesame cake is a by‐product of sesame oil industry. In this study, the effect of extraction methods (maceration and sonication) and solvents (ethanol, methanol, ethanol/water (50:50), methanol/water (50:50), and water) on the antioxidant properties of sesame cake extracts are evaluated to determine the most suitable extraction method for optimal use of this product. Total phenolic content is measured according to the Folin–Ciocalteu method and antioxidant activities of each extract are evaluated with the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), β‐carotene bleaching, and ferric reducing/antioxidant power (FRAP) methods. The highest amount of total phenolic compounds is observed in ethanol‐ultrasonic extract with the amount of 88.89 mg/g gallic acid equivalent. Methanol‐ultrasonic extract with the amount of 88.475% indicates the highest activity in scavenging DPPH free radicals. In β‐carotene‐linoleic acid system, ethanol‐ultrasonic extract indicates the highest inhibition percent of 45.64. In FRAP assay, ethanol/water (50:50)‐maceration and ethanol/water (50:50)‐ultrasonic extracts with the absorption of 1.132 and 1.0745 nm indicate the highest antioxidant activity.
Müller glial cells inhibit proliferation of retinal endothelial cells via TGF‐β2 and Smad signaling
Authors: Yafai Yousef , Iandiev Ianors , Lange Johannes , Unterlauft Jan Darius , Wiedemann Peter , Bringmann Andreas , Reichenbach Andreas , Eichler Wolfram
Published: May 2014

Neovascularization is a sight‐threatening complication of ischemic proliferative retinopathies. Transforming growth factor (TGF)‐β, a cytokine with multiple functions in the retina, participates in the control of pathological angiogenesis and neovascularization. Retinal glial (Müller) cells produce TGF‐β2 under physiological and post‐ischemic conditions. To characterize glial cell‐derived mediators of angiogenesis regulation in glial‐endothelial interactions in the retina, we co‐cultured primary Müller cells and bovine microvascular retinal endothelial cells (BRECs). Müller cell‐derived TGF‐β2 was bound by the BRECs, which were found to express serine/threonine kinase TGF‐β receptors, and stimulated TGF‐β‐dependent anti‐proliferative signaling pathways. The proliferation of BRECs was attenuated by exogenous TGF‐β2 as well as by the presence of Müller cell culture media. The following intracellular signaling mechanisms were found to be involved in the anti‐angiogenic action of Müller cell‐derived TGF‐β2: (i) binding of TGF‐β2 to BRECs is mediated by the type‐II TGF‐β receptor, leading to (ii) activation and phosphorylation of receptor‐activated Smads; (iii) Müller cell‐derived TGF‐β2 activates Smad2 and Smad3 to (iv) attenuate the phosphorylation state of the MAP kinases, extracellular signal‐regulated kinase (ERK)‐1/‐2. Neutralizing TGF‐β or TGF‐β type‐II receptor or blocking the activation of Smads partially abrogated the effect of Müller cell‐conditioned media on BRECs. Together, our data suggest that Müller cells release TGF‐β2, inhibiting the proliferation of retinal endothelial cells via activation of Smad2/Smad3 and attenuation of ERK signaling. Given the context‐dependent action of TGF‐β2 on angiogenesis, our results may have implications for understanding the pathogenesis of retinal angiopathies, such as diabetic retinopathy, and the anti‐angiogenic role of TGF‐β therein. GLIA 2014;62:1476–1485