bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of α‐cellulose/polypyrrole composite for the removal of reactive red dye from aqueous solution: Kinetics and equilibrium modeling
Authors: Ovando‐Medina Víctor M. , Vizcaíno‐Mercado Josué , González‐Ortega Omar , Rodríguez de la Garza José A. , Martínez‐Gutiérrez Hugo
Published: February 2014

In this work, a composite from α‐cellulose coated with conducting polypyrrole by in situ polymerization using potassium persulfate as oxidant was obtained. The composite was characterized by fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry, UV/Vis spectroscopy, and scanning electron microscopy (SEM) analysis showed homogeneous coating of α‐cellulose with polypyrrole (PPy) to produce a composite with a conductivity of 3.5 × 10−5 S/m. Batch aqueous adsorption experiments of the reactive red 120 (RR120) dye onto the synthesized material were conducted. The results showed that this composite is an efficient adsorbent for RR120 dye removal. For the adsorption experiments set to an initial pH of 3.9, the adsorption capacity was 15.6 mg of dye/g of composite for an equilibrium concentration (in the liquid) of RR120 dye equal to 1,000 mg/L, whereas a value of 96.1 mg of dye/g of composite was obtained when the solution pH was set to 2.0 for the same equilibrium concentration. When performing adsorption experiments using pure α‐cellulose, dye adsorption was insignificant at any pH value. Adsorption isotherm for RR120 was described by a typical Freundlich model. The transient adsorption of RR120 on the synthesized composite was described by a general three‐resistance model that includes the transport on the film that surrounds the composite particles, diffusion inside the particles, and adsorption on the surface of the particles. A fitting of the uptake curves was performed allowing the estimation of values for the effective diffusivity, D0, and the adsorption rate coefficient, k1. For the adsorption experiments with an initial pH value set to 3.9, D0 was estimated as 1.05 × 10−10 m2/s, whereas k1 was 1.65 × 10−4 Ln/g mgn − 1 s; the corresponding values of k1 at pH = 2 and 9.0 were 3.18 × 10−4 and 5.16 × 10−5, respectively. POLYM. COMPOS., 36:312–321, 2015. © 2014 Society of Plastics Engineers
Spike‐in SILAC proteomic approach reveals the vitronectin as an early molecular signature of liver fibrosis in hepatitis C infections with hepatic iron overload
Authors: Montaldo Claudia , Mattei Simone , Baiocchini Andrea , Rotiroti Nicolina , Nonno Franca Del , Pucillo Leopoldo Paolo , Cozzolino Angela Maria , Battistelli Cecilia , Amicone Laura , Ippolito Giuseppe , van Noort Vera , Conigliaro Alice , Alonzi Tonino , Tripodi Marco , Mancone Carmine
Published: February 2014

Hepatitis C virus (HCV)‐induced iron overload has been shown to promote liver fibrosis, steatosis, and hepatocellular carcinoma. The zonal‐restricted histological distribution of pathological iron deposits has hampered the attempt to perform large‐scale in vivo molecular investigations on the comorbidity between iron and HCV. Diagnostic and prognostic markers are not yet available to assess iron overload‐induced liver fibrogenesis and progression in HCV infections. Here, by means of Spike‐in SILAC proteomic approach, we first unveiled a specific membrane protein expression signature of HCV cell cultures in the presence of iron overload. Computational analysis of proteomic dataset highlighted the hepatocytic vitronectin expression as the most promising specific biomarker for iron‐associated fibrogenesis in HCV infections. Next, the robustness of our in vitro findings was challenged in human liver biopsies by immunohistochemistry and yielded two major results: (i) hepatocytic vitronectin expression is associated to liver fibrogenesis in HCV‐infected patients with iron overload; (ii) hepatic vitronectin expression was found to discriminate also the transition between mild to moderate fibrosis in HCV‐infected patients without iron overload.
DFT and MP2 Study of Intermolecular Interaction of 5‐Aminotetrazole and Hydrazine: Enthalpy of Formation of Hydrazinium 5‐Aminotetrazolate in the Gas Phase
Authors: Najafi Chermahini Alireza , Farrokhpour Hossein , Eghbalsaeid Mohammadbagher , Teimouri Abbas
Published: February 2014

The tautomerism of all possible forms of 5‐aminotetrazole (AT1–AT7) in the gas phase and continuum solvent was studied theoretically. The calculations were separately performed at the MP2 and CAM‐B3LYP levels of theory, using the 6‐311++G(d,p) basis set. It was found that 5‐aminotetrazole in the 2H form (AT1) is the most stable isomer in both the gas phase and in solution. In addition, the aggregation of various isomers of 5‐aminotetrazole with hydrazine was investigated in the gas phase and in solution. Finally, the standard enthalpy of formations of the different structures of hydrazinium 5‐aminotetrazolate was determined in the gas phase. Using the calculated standard enthalpy of formation of different structures of hydrazinium 5‐aminotetrazolate in the gas phase and considering their Boltzmann population ratios, a single value has been reported for the standard enthalpy of formation of hydrazinium 5‐aminotetrazolate considering all of the tautomers. The calculated values are in excellent agreement with the experimentally reported heat of formation for the hydrazinium 5‐aminotetrazolate.
Energetic Salts of 5‐(5‐Azido‐1H‐1,2,4‐triazol‐3‐yl)tetrazole
Authors: Huber Stefan , Izsák Dániel , Karaghiosoff Konstantin , Klapötke Thomas M. , Reuter Stephan
Published: February 2014

Several metal and nitrogen‐rich salts of the recently presented 5‐(5‐azido‐1H‐1,2,4‐triazol‐3‐yl)tetrazole (AzTT), including silver (1), copper(I) (2), potassium (3), cesium (4), copper(II) (7), ammonium (8), and guanidinium (9), as well as the respective double‐salts of 3, 4, 8 and 9, were prepared and well characterized by IR and multinuclear (1H, 13C, 14N) NMR spectroscopy, DSC, mass spectrometry, elemental analysis and one (4) additionally by single‐crystal X‐ray diffraction. The sensitivities towards impact, friction and electrostatic discharge were determined according to BAM standards, revealing most of the metal salts as highly sensitive and the nitrogen‐rich salts as insensitive. The metal salts were further tested for their ability of being primary explosives.
Technology for III‐N heterogeneous mixed‐signal electronics
Authors: Chen Kevin J. , Kwan Alex Man Ho , Jiang Qimeng
Published: February 2014

III‐N devices are suitable for high power RF/microwave amplifier, high temperature electronics, and power switches applications, and the peripheral mixed‐signal electronics with sensing, protection, and control functions could provide optimized performance, increased functionality, and enhanced reliability. This paper addresses the technology to discuss the technology options of implementing III‐N mixed‐signal circuits, and then reviews the recent progress in the expansion of design library, based on monolithically integrated enhancement/depletion (E/D)‐mode AlGaN/GaN HEMTs on GaN‐on‐silicon substrates.

An integrated GaN proportional‐to‐absolute‐temperature (PTAT) voltage source.
Fabrication of MEA‐based nanocavity sensor arrays for extracellular recording of action potentials
Authors: Czeschik Anna , Offenhäusser Andreas , Wolfrum Bernhard
Published: February 2014

Nanocavity sensor arrays are powerful devices for parallel extracellular recordings of action potentials from cell networks. The sensors combine a high spatial resolution and seal resistance between cell and electrode with low electrode impedances, allowing low‐noise electrophysiological measurements of individual cells in a network without the use of CMOS technology. In this paper, we present a new protocol for the simple fabrication of nanocavity sensors, which enables easy modification of standard microelectrode arrays. Our approach enables processing of devices with improved sensor characteristics and flexibility regarding electrode area and aperture size with minimal effort. We characterize the sensors by impedance spectroscopy and demonstrate their applicability by recording action potentials of individual cardiomyocyte‐like cells growing in a network on the chip surface.
Insulin‐Sensitizing and Beneficial Lipid‐Metabolic Effects of the Water‐Soluble Melanin Complex Extracted from Inonotus obliquus
Authors: Lee Jung‐Han , Hyun Chang‐Kee
Published: February 2014

Inonotus obliquus has been traditionally used for treatment of metabolic diseases; however, the mechanism remains to be elucidated. In this study, we found that the water‐soluble melanin complex extracted from I. obliquus improved insulin sensitivity and reduced adiposity in high fat (HF)‐fed obese mice. When the melanin complex was treated to 3T3‐L1 adipocytes, insulin‐stimulated glucose uptake was increased significantly, and its phosphoinositide 3‐kinase‐dependent action was proven with wortmannin treatment. Additionally, dose‐dependent increases in Akt phosphorylation and glucose transporter 4 translocation into the plasma membrane were observed in melanin complex‐treated cells. Adiponectin gene expression in 3T3‐L1 cells incubated with melanin complex increased which was corroborated by increased AMP‐activated protein kinase phosphorylation in HepG2 and C2C12 cells treated with conditioned media from the 3T3‐L1 culture. Melanin complex‐treated 3T3‐L1 cells showed no significant change in expression of several lipogenic genes, whereas enhanced expressions of fatty acid oxidative genes were observed. Similarly, the epididymal adipose tissue of melanin complex‐treated HF‐fed mice had higher expression of fatty acid oxidative genes without significant change in lipogenic gene expression. Together, these results suggest that the water‐soluble melanin complex of I. obliquus exerts antihyperglycemic and beneficial lipid‐metabolic effects, making it a candidate for promising antidiabetic agent. Copyright © 2014 John Wiley & Sons, Ltd.
Molecular switch properties of 7‐hydroxyquinoline compounds
Authors: Csehi András , Halász Gábor J. , Vibók Ágnes
Published: February 2014

The present study is concerned with the theoretical study of possible molecular switch systems. The 7‐hydroxyquinoline‐8‐carboxamide molecule and its single‐, double‐, and triple‐substituted derivatives are investigated with the aim of revealing characteristic switch features. Molecular switches can be considered as composed of a frame and a crane component. According to a recent study, the 7‐hydroxyquinoline double‐ring system constitutes the frame moiety, while a carboxamide group at position 8 plays the role of the crane part (Csehi et al., Phys. Chem. Chem. Phys. 2013, 15, 18048). The effect of single 2‐,4‐,6‐methyl, double 2,4‐, 2,6‐diamino, and triple 2,4,6‐triamino substitutions to the molecular frame has been investigated using high level ab initio techniques. As a possible reaction mechanism, excited state intramolecular hydrogen transfer mediated by the frame‐crane torsion has been considered. At the terminal structures of this pathway, second‐order approximate coupled‐cluster (CC2) quality vertical excitation energies and oscillator strengths have been calculated for the three lowest‐lying singlet electronic excited states of all the studied systems. Single point calculations at selected geometries of the reaction path were carried out at the CC2 level as well, while conical intersections (CIs) between the ground and first excited states near perpendicular twisted geometries were optimized using the complete active space self‐consistent field method. To confirm the presence of CIs, nonadiabatic coupling terms have been derived and applying the topological line integral technique, the topological (or Berry) phase has been calculated surrounding the point of CI. The results of this work clearly demonstrate the fulfillment of several molecular switch properties by the investigated quinoline derivatives. An extensive comparison between the different compounds is presented as well. © 2014 Wiley Periodicals, Inc.
Observation of Fano Resonances in All‐Dielectric Nanoparticle Oligomers
Authors: Chong Katie E. , Hopkins Ben , Staude Isabelle , Miroshnichenko Andrey E. , Dominguez Jason , Decker Manuel , Neshev Dragomir N. , Brener Igal , Kivshar Yuri S.
Published: February 2014

It is well‐known that oligomers made of metallic nanoparticles are able to support sharp Fano resonances originating from the interference of two plasmonic resonant modes with different spectral width. While such plasmonic oligomers suffer from high dissipative losses, a new route for achieving Fano resonances in nanoparticle oligomers has opened up after the recent experimental observations of electric and magnetic resonances in low‐loss dielectric nanoparticles. Here, light scattering by all‐dielectric oligomers composed of silicon nanoparticles is studied experimentally for the first time. Pronounced Fano resonances are observed for a variety of lithographically‐fabricated heptamer nanostructures consisting of a central particle of varying size, encircled by six nanoparticles of constant size. Based on a full collective mode analysis, the origin of the observed Fano resonances is revealed as a result of interference of the optically‐induced magnetic dipole mode of the central particle with the collective mode of the nanoparticle structure. This allows for effective tuning of the Fano resonance to a desired spectral position by a controlled size variation of the central particle. Such optically‐induced magnetic Fano resonances in all‐dielectric oligomers offer new opportunities for sensing and nonlinear applications.
Revisiting Teacher Feedback in EFL Writing from Sociocultural Perspectives
Authors: Lee Icy
Published: February 2014

While research on teacher feedback has largely been influenced by second language writing and second language acquisition perspectives, little attention has been paid to the contextual and sociocultural dimension of teachers' work. Overall, there is a dearth of discussion on teacher feedback that is influenced by sociocultural perspectives. Drawing on mediated learning experience (MLE) theory, this article discusses the limitations of conventional feedback approaches in English as a foreign language school contexts and underscores the need to replace these approaches with more effective practices typical for the process‐oriented writing classroom, so that feedback can mediate student learning. Informed by activity theory (AT), the article further suggests that providing MLE as a new object of the feedback system and introducing other innovations can lead to more effective feedback and help students improve learning. The article concludes with suggestions for research informed by MLE and AT perspectives.
Cooperative Q‐learning techniques for distributed online power allocation in femtocell networks
Authors: Saad Hussein , Mohamed Amr , ElBatt Tamer
Published: February 2014

In this paper, we address the problem of distributed interference management of femtocells that share the same frequency band with macrocells using distributed multi‐agent Q‐learning. We formulate and solve two problems representing two different Q‐learning algorithms, namely, femto‐based distributed and sub‐carrier‐based distributed power controls using Q‐learning (FBDPC‐Q and SBDPC‐Q). FBDPC‐Q is a multi‐agent algorithm that works on a global basis, for example, deals with the aggregate macrocell and femtocell capacities. Its complexity increases exponentially with the number of sub‐carriers in the system. Also, it does not take into consideration the sub‐carrier macrocell capacity as a constraint. To overcome these problems, SBDPC‐Q is proposed, which is a multi‐agent algorithm that works on a sub‐carrier basis, for example, sub‐carrier macrocell and femtocell capacities. Each of FBDPC‐Q and SBDPC‐Q works in three different learning paradigms: independent (IL), cooperative (CL), and weighted cooperative (WCL). IL is considered the simplest form for applying Q‐learning in multi‐agent scenarios, where all the femtocells learn independently. CL and WCL are the proposed schemes in which femtocells share partial information during the learning process in order to strike a balance between practical relevance and performance. We prove the convergence of the CL paradigm when used in the FBDPC‐Q algorithm. We show via simulations that the CL paradigm outperforms the IL paradigm in terms of the aggregate femtocell capacity, especially in networks with large number of femtocells and large number of power levels. In addition, we propose WCL to address the CL limitations. Finally, we evaluate the robustness and scalability of both FBDPC‐Q and SBDPC‐Q, against several typical dynamics of plausible wireless scenarios (fading, path loss, random activity of femtocells, etc.). We show that the CL paradigm is the most scalable to large number of femtocells and robust to the network dynamics compared with the IL and WCL paradigms. Copyright © 2014 John Wiley & Sons, Ltd.
Overview on evolutionary subgroup discovery: analysis of the suitability and potential of the search performed by evolutionary algorithms
Authors: Carmona Cristóbal J. , González Pedro , del Jesus María José , Herrera Francisco
Published: February 2014

Subgroup discovery (SD) is a descriptive data mining technique using supervised learning. In this article, we review the use of evolutionary algorithms (EAs) for SD. In particular, we will focus on the suitability and potential of the search performed by EAs in the development of SD algorithms. Future directions in the use of EAs for SD are also presented in order to show the advantages and benefits that this search strategy contribute to this task.

This article is categorized under:

Technologies > Computational Intelligence
Effects of antibacterial agents and drugs monitored by atomic force microscopy
Authors: Longo Giovanni , Kasas Sandor
Published: February 2014

Originally invented for topographic imaging, atomic force microscopy (AFM) has evolved into a multifunctional biological toolkit, enabling to measure structural and functional details of cells and molecules. Its versatility and the large scope of information it can yield make it an invaluable tool in any biologically oriented laboratory, where researchers need to perform characterizations of living samples as well as single molecules in quasi‐physiological conditions and with nanoscale resolution. In the last 20 years, AFM has revolutionized the characterization of microbial cells by allowing a better understanding of their cell wall and of the mechanism of action of drugs and by becoming itself a powerful diagnostic tool to study bacteria. Indeed, AFM is much more than a high‐resolution microscopy technique. It can reconstruct force maps that can be used to explore the nanomechanical properties of microorganisms and probe at the same time the morphological and mechanical modifications induced by external stimuli. Furthermore it can be used to map chemical species or specific receptors with nanometric resolution directly on the membranes of living organisms. In summary, AFM offers new capabilities and a more in‐depth insight in the structure and mechanics of biological specimens with an unrivaled spatial and force resolution. Its application to the study of bacteria is extremely significant since it has already delivered important information on the metabolism of these small microorganisms and, through new and exciting technical developments, will shed more light on the real‐time interaction of antimicrobial agents and bacteria.

This article is categorized under:

Diagnostic Tools > Diagnostic Nanodevices

Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Four CoII/MnII Coordination Compounds Constructed from Dipyrido[3,2‐d:2′,3′‐f]quinoxaline and Different Dicarboxylates: Electrochemical, Photoluminescent, and Magnetic Properties
Authors: Liu Guo‐Cheng , Qu Yun , Wang Xiu‐Li , Zhang Ju‐Wen , Kan Xiao‐Min , Chen Nai‐Li
Published: February 2014

Four CoII/MnII coordination compounds, namely, [Co(dpq)(L1)(H2O)1.5] (1), [Co(dpq)(L2)(H2O)2]·H2O (2), [Mn2(dpq)2(L2)2]·2H2O (3), and [Mn(dpq)(L3)] (4) [H2L1 = 5‐methylisophthalic acid, H2L2 = 5‐hydroxyisophthalic acid, and H2L3 = bis(sulfanediyl) thiadiazole diacetic acid] were obtained from hydrothermal reactions of dipyrido [3,2‐d:2′,3′‐f]quinoxaline (dpq) and three structurally related mixed dicarboxylate ligands. Single crystal X‐ray diffraction analysis reveals that compound 1 consists of a dinuclear CoII cluster linked by two carboxylate groups from different L1 anions and a coordination water molecule. Compound 2 is a dimeric structure based on a pair of L2 anions and two CoII ions. Both compounds are finally extended into three dimensional (3D) supramolecular networks by hydrogen bonding and π–π stacking interactions. In compound 3, two MnII ions are linked by a pair of carboxylate groups to form a bimetallic unit, which is extended by pairs of L2 anions to generate a 1D wave‐like band. The adjacent bands are linked by hydrogen bonding interactions forming a 2D supramolecular architecture. Compound 4 is a (4,4)‐connected 2D network based on L3 linkers and dinuclear MnII units connected by two carboxylate groups. The effects of metal ions and dicarboxylates with different spacers on the architectures of the title compounds were discussed. Moreover, the electrochemical behavior of compounds 1 and 2, magnetic properties of compounds 1, 3, and 4, and photoluminescent properties of compounds 1–4 were investigated.
Phylogeography and genetic structure of disjunct Salix arbutifolia populations in Japan
Authors: Nagamitsu Teruyoshi , Hoshikawa Takeshi , Kawahara Takayuki , Barkalov Vyacheslav Yu. , Sabirov Renat N.
Published: February 2014

Disjunct geographic distributions of boreal plant species at the southern edges of their ranges are expected to result in low genetic diversity and high genetic differentiation in the disjunct populations. This prediction was tested in a riparian willow, Salix arbutifolia, distributed in the northeastern Eurasian continent and the Sakhalin, Hokkaido, and Honshu Islands, using chloroplast DNA haplotypes and nuclear microsatellite genotypes. Hokkaido and Honshu populations shared a chloroplast haplotype identical to a closely related species, S. cardiophylla. This haplotype was divergent from haplotypes in the Eurasian continent (Primorsky) and the Sakhalin Island. In the nuclear microsatellites, most Hokkaido populations were genetically closer to Primorsky populations than to Sakhalin populations in spite of the geographical vicinity between Sakhalin and Hokkaido. The unexpected genetic divergence between Sakhalin and Hokkaido implies a complicated history of migration and colonization. The most peripheral populations in Honshu had the lowest genetic diversity and were most differentiated from the others. Thus, low genetic diversity and high genetic differentiation at the range periphery suggest substantial effects of genetic drift on genetic structure in the disjunct populations of Salix arbutifolia at the southern edge of its range.
An Exploration of Genetic Counselors’ Needs and Experiences with Prenatal Chromosomal Microarray Testing
Authors: Bernhardt Barbara A. , Kellom Katherine , Barbarese Alexandra , Faucett W. Andrew , Wapner Ronald J.
Published: February 2014

Because of the higher yield over traditional chromosomal analysis, chromosomal microarray analysis (CMA) is being used increasingly in prenatal diagnosis. Unfortunately, the clinical implication of many copy number variants found on prenatal CMA is uncertain, complicating genetic counseling. Recognizing that uncertain results will be encountered frequently as more of the genome is assayed prenatally, we set out to understand the experiences and needs of genetic counselors when counseling patients about uncertain prenatal microarray results, their comfort with various aspects of prenatal genetic counseling, and their interest in additional education and training about prenatal microarray testing. We first interviewed 10 genetic counselors about their experiences of providing pre‐ and post‐test genetic counseling about prenatal CMA. Based on the findings from the counselor interviews, we developed items for a survey to assess the prevalence of genetic counselors’ attitudes towards, experience and comfort with, and educational needs regarding prenatal CMA. Based on surveys completed by 193 prenatal genetic counselors, we found that when there is an uncertain CMA result, only 59 % would be comfortable providing genetic counseling and only 43 % would be comfortable helping a patient make a decision about pregnancy termination. Being less comfortable was associated with seeing fewer patients having prenatal CMA testing. Respondents expressed a high degree of interest in additional education about prenatal CMA and counseling about uncertain results. Further genetic counselor education and training aimed at improving counselors’ personal comfort with uncertain results and communicating about them with patients is needed.
Do PFT1 and HY5 interact in regulation of sulfate assimilation by light in Arabidopsis?
Authors: Koprivova Anna , Calderwood Alexander , Lee Bok-Rye , Kopriva Stanislav
Published: February 2014

Sulfate assimilation pathway is highly responsive to changes in environment, but the mechanisms of such regulation are only slowly beginning to unravel. Here we show evidence that PHYTOCHROME AND FLOWERING TIME 1 (PFT1) may be another component of the sulfate assimilation regulatory circuit. Transcriptional regulation by light of the key enzyme of sulfate assimilation, adenosine 5′phosphosulfate (APS) reductase, is disturbed in pft1‐2 mutants. PFT1, however, affects also APS reductase enzyme activity, flux through the sulfate assimilation pathway and accumulation of glutathione. In addition, our data suggest a possible interplay of PFT1 with another transcription factor, HY5, in regulation of APS reductase by light.
C/EBP‐α, involvement of a novel transcription factor in leptin‐induced VCAM‐1 production in mouse chondrocytes
Authors: Kang Xia , Xie Qing-Yun , Zhou Jing-Song , Zhang Bo , Liao Dong-Fa , Wu Hong-Hua , Zheng Wei , Pan Xian-Ming , Quan Yi
Published: February 2014

Leptin and vascular cell adhesion molecules‐1 (VCAM‐1) are two important mediators in obesity‐related osteoarthritis, while the molecular mechanism linking leptin to VCAM‐1 production is still obscure. Here we show that leptin upregulates VCAM‐1 mRNA and protein levels in a time‐ and dose‐dependent manner. Mechanistically, leptin induces VCAM‐1 promoter activity by increasing the expression of C/EBP‐α and facilitating its binding to a newly identified element in the VCAM‐1 gene. Gain or loss of function studies reveal a regulatory role of C/EBP‐α on VCAM‐1 expression. Finally, elevated plasma leptin level correlates to increased C/EBP‐α and VCAM‐1 production in chondrocytes from obese mice.
Identification of the synaptic vesicle glycoprotein 2 receptor binding site in botulinum neurotoxin A
Authors: Strotmeier Jasmin , Mahrhold Stefan , Krez Nadja , Janzen Constantin , Lou Jianlong , Marks James D. , Binz Thomas , Rummel Andreas
Published: February 2014

Botulinum neurotoxins (BoNTs) inhibit neurotransmitter release by hydrolysing SNARE proteins. The most important serotype BoNT/A employs the synaptic vesicle glycoprotein 2 (SV2) isoforms A‐C as neuronal receptors. Here, we identified their binding site by blocking SV2 interaction using monoclonal antibodies with characterised epitopes within the cell binding domain (HC). The site is located on the backside of the conserved ganglioside binding pocket at the interface of the HCC and HCN subdomains. The dimension of the binding pocket was characterised in detail by site directed mutagenesis allowing the development of potent inhibitors as well as modifying receptor binding properties.
African Films in the Classroom
Authors: Gugler Josef
Published: February 2014

A wealth of excellent films from Africa is readily available for classroom use, even if much of Anglophone Africa remains poorly represented. African films can serve to challenge students' assumptions and to foster a critical examination of Western films set in Africa. Extending the scope of conventional “African” courses to North Africa adds a substantial body of notable productions, some of which address current concerns such as Islamic fundamentalism. African films have to be contextualized; even when they are examined as works of art and as examples of world cinema, full appreciation requires that they be considered in their historical and cultural contexts. When films are used to introduce students to Africa, critical examination is imperative—audiences that have little factual information about Africa all too readily assume that fiction and fact coincide.
Getting Close to Rwandans since the Genocide: Studying Everyday Life in Highly Politicized Research Settings
Authors: Thomson Susan
Published: February 2014

Research with people in highly politicized research settings illuminates the gap between the images that most African governments strive to represent and the sociopolitical realities of everyday life. This article discusses the opportunities and challenges of doing research in postgenocide Rwanda and is a useful resource for researchers contemplating their own projects under such conditions, whether in Rwanda or elsewhere. It discusses the importance of creating personal relationships and meeting people on their terms, as well as such topics as the identification of the research site, building rapport and trust with respondents, safeguarding anonymity and confidentiality, and working with local research assistants and partners.
Postcolonial Cosmopolitan Music in Dar es Salaam: Dr. Remmy Ongala and the Traveling Sounds
Authors: Sanga Imani
Published: February 2014

This article concerns Dr. Remmy Ongala, a Congolese-Tanzanian musician, and the making of postcolonial cosmopolitan music in Dar es Salaam, Tanzania. It argues that Dr. Remmy's music is shaped by the postcolonial consciousness and conditions of contemporary Tanzania. It also shows Dr. Remmy's cosmopolitan citizenship in his songs that address political and social issues. Focusing on his involvement in worldbeat festivals, it argues that he, like other musicians, enters into the worldbeat system not as a fully autonomous individual but as a constituted postcolonial subject, compelled to shape his music in accordance with the demands of the worldbeat system.
The Clergy, Culture, and Political Conflicts in Nigeria
Authors: Adebanwi Wale
Published: February 2014

This article explores contemporary manifestations of the politicization of culture by the Christian clergy in the determination and resolution of political conflicts in Nigeria in general and Yonibaland in particular—against die backdrop of what has been called “the civilizational hegemony of Christianity.” The article approaches religion and the practices it enables as part of a cultural system through which we can capture the specific ways in which religious audiorities pursue political and ethnocultural interests to justify a particular social order.
The Sight, Sound, and Global Traffic of Blackness inBlood Diamond
Authors: Chrisman Laura
Published: February 2014

This article explores the representation of Africa in director Edward Zwick's 2006 filmBlood Diamond, examining in particular the ways in which the film's liberal-humanitarian orientation works to demonize black African communities, nationalisms, and governments while constituting a white and largely American subject as the center of ethical value. The article also examines the film's account of diamond consumption as a global phenomenon, and considers the ways in which sound and vision operate to devalue black diasporic as well as black continental African subjects.
Homophobic Africa? Toward A More Nuanced View
Authors: Awondo Patrick , Geschiere Peter , Reid Graeme
Published: February 2014

The recent emergence of homosexuality as a central issue in public debate in various parts of Africa has encouraged a stereotypical image of one homophobic Africa, often placed in opposition to a tolerant or depraved West. What is striking is that this image of Africa as homophobic is promoted by both traditionalists who insist that homosexuality is a Western intrusionand bythe Western media that focus on homophobic statements from African political and religious leaders. What both neglect, however, is the existence of internal debate and disagreements among Africans on the subject of homosexuality. In this article we try to counter this image of a homophobic Africa with a more nuanced discussion, including a comparison of different trajectories in the emergence of homosexuality as a public issue in four countries (Senegal, Cameroon, Uganda, and South Africa). The comparison highlights considerable variations in the ways in which the issue became politicized. There is a world of difference, for example, between the image of the homosexual asun Grand(a rich and powerful “Big Man”) who imposes anal penetration as a supreme form of subjection (as in Cameroon or Gabon, where homosexuality is associated with witchcraft and other occult forces; compare Achille Mbembe's visionary evocation of a “phallocracy”) and the often quite marginal persons who become victims of gay persecution in other contexts. More insight into the variations of what is loosely and inaccurately called “homophobia” can help connect international pressures for decriminalization and protection to local circumstances. Working through local activists is crucial for the effort to counter homophobia in Africa.
Are cryptic species a problem for parasitological biological tagging for stock identification of aquatic organisms?
Authors: BRAY RODNEY A. , CRIBB THOMAS H.
Published: February 2014

The effective use of biological tags in stock assessment relies on the reliable identification of the parasites concerned. This may be compromised if cryptic species are not recognized. Here we review what is known about cryptic species in aquatic hosts and its potential importance in this respect. Although strictly cryptic species may be considered as species which can be distinguished only by molecular data, we accept the far looser but more practical definition of species that cannot be readily distinguished morphologically. Cryptic species appear to have been identified most frequently as occurring in separate host species; this is heartening in that this has no significant impact on tagging studies. But cryptic species have occasionally been identified in single hosts sympatrically and are relatively common in geographically distinct populations of the same host species. Ignorance of both kinds of occurrences has the capacity to undermine the reliability of tagging analysis. We review in detail what is known of intra- and interspecific genetic variation over geographical ranges in the trematodes, based on recent molecular studies. Although the existence of cryptic species and evidence of intraspecific variability may appear daunting, we suspect that these complexities will add, and indeed have already added, to the sophistication of the information that can be derived from tagging studies.
Single, dual and multiple respiratory virus infections and risk of hospitalization and mortality
Authors: GOKA E. A. , VALLELY P. J. , MUTTON K. J. , KLAPPER P. E.
Published: February 2014

Respiratory virus infections cause a significant number of hospitalization and deaths globally. This study investigated the association between single and multiple respiratory virus infections and risk of admission to a general ward, intensive care unit or death in patients aged 0–105 years (mean ± s.d. = 24·4 ± 24·1 years), from North West England, that were tested for respiratory virus infections between January 2007 and June 2012. The majority of infections were in children aged ⩽5 years. Dual or multiple infections occurred in 10·4% (1214/11 715) of patients, whereas single infection occurred in 89·6% (10 501/11 715). Rhinovirus was the most common co-infecting virus (occurring in 69·5%; 844/1214 of co-infections). In a multivariate logistic regression model, multiple infections were associated with an increased risk of admission to a general ward [odds ratio (OR) 1·43, 95% confidence interval (CI) 1·2–1·7,P < 0·0001]. On the other hand, patients with respiratory syncytial virus (RSV) and human parainfluenza virus types 1–3 (hPIV1–3), as a single infection, had a higher risk of being admitted to a general ward (OR 1·49, 95% CI 1·28–1·73,P < 0·0001 and OR 1·34, 95% CI 1·003–1·8,P = 0·05, respectively); admitted to an intensive-care unit or dying (OR 1·5, 95% CI 1·20–2·0,P = 0·001 and OR 1·60, 95% CI 1·02–2·40,P = 0·04, respectively). This result emphasizes the importance of RSV, hPIV and mixed infections and calls for research on vaccines, drugs and diagnostic tests targeting these respiratory viruses.
Immuno-Electron Microscopy of Primary Cell Cultures from Genetically Modified Animals in Liquid by Atmospheric Scanning Electron Microscopy
Authors: Kinoshita Takaaki , Mori Yosio , Hirano Kazumi , Sugimoto Shinya , Okuda Ken-ichi , Matsumoto Shunsuke , Namiki Takeshi , Ebihara Tatsuhiko , Kawata Masaaki , Nishiyama Hidetoshi , Sato Mari , Suga Mitsuo , Higashiyama Kenichi , Sonomoto Kenji , Mizunoe Yoshimitsu , Nishihara Shoko , Sato Chikara
Published: February 2014

High-throughput immuno-electron microscopy is required to capture the protein–protein interactions realizing physiological functions. Atmospheric scanning electron microscopy (ASEM) allowsin situcorrelative light and electron microscopy of samples in liquid in an open atmospheric environment. Cells are cultured in a few milliliters of medium directly in the ASEM dish, which can be coated and transferred to an incubator as required. Here, cells were imaged by optical or fluorescence microscopy, and at high resolution by gold-labeled immuno-ASEM, sometimes with additional metal staining. Axonal partitioning of neurons was correlated with specific cytoskeletal structures, including microtubules, using primary-culture neurons from wild typeDrosophila, and the involvement of ankyrin in the formation of the intra-axonal segmentation boundary was studied using neurons from anankyrin-deficient mutant. Rubella virus replication producing anti-double-stranded RNA was captured at the host cell’s plasma membrane. Fas receptosome formation was associated with clathrin internalization near the surface of primitive endoderm cells. Positively charged Nanogold clearly revealed the cell outlines of primitive endoderm cells, and the cell division of lactic acid bacteria. Based on these experiments, ASEM promises to allow the study of protein interactions in various complexes in a natural environment of aqueous liquid in the near future.
Metastable Structures in Al Thin Films Before the Onset of Corrosion Pitting as Observed using Liquid Cell Transmission Electron Microscopy
Authors: Chee See Wee , Duquette David J. , Ross Frances M. , Hull Robert
Published: February 2014

One of the fundamental challenges in understanding the early stages of corrosion pitting in metals protected with an oxide film is that there are relatively few techniques that can probe microstructure with sufficient resolution while maintaining a wet environment. Here, we demonstrate that microstructural changes in Al thin films caused by aqueous NaCl solutions of varying chloride concentrations can be directly observed using a liquid flow cell enclosed within a transmission electron microscope (TEM) holder. In the absence of chloride, Al thin films did not exhibit significant corrosion when immersed in de-ionized water for 2 days. However, introducing 0.01 M NaCl solutions led to extensive random formation of blisters over the sample surface, while 0.1 M NaCl solutions formed anomalous structures that were larger than the typical grain size. Immersion in 1.0 M NaCl solutions led to fractal corrosion consistent with previously reported studies of Al thin films using optical microscopy. These results show the potential of in situ liquid cell electron microscopy for probing the processes that take place before the onset of pitting and for correlating pit locations with the underlying microstructure of the material.
InAlN/GaN HEMTs based L-band high-power packaged amplifiers
Authors: Jardel Olivier , Jacquet Jean-Claude , Baczkowski Lény , Carisetti Dominique , Lancereau Didier , Olivier Maxime , Aubry Raphaël , di Forte Poisson Marie-Antoinette , Dua Christian , Piotrowicz Stéphane , Delage Sylvain L.
Published: February 2014

This paper presents power results of L-band packaged hybrid amplifiers using InAlN/GaN/SiC HEMT power dies. The high-power densities achieved both in pulsed and continuous wave (cw) modes confirm the interest of such technology for high-frequency, high-power, and high-temperature operation. We present here record RF power measurements for different versions of amplifiers. Up to 260 W, i.e. 3.6 W/mm, in pulsed (10 µs/10%) conditions, and 105 W, i.e. 2.9 W/mm, in cw conditions were achieved. Such results are made possible thanks to the impressive performances of InAlN/GaN transistors, even when operating at high temperatures. Unit cell transistors deliver output powers of 4.3 W/mm at Vds = 40 V in the cw mode of operation at the frequency of 2 GHz. The transistor process is described here, as well as the amplifiers design and measurements, with a particular focus to the thermal management aspects.
Evidence for external forcing of the Atlantic Multidecadal Oscillation since termination of the Little Ice Age
Authors: Knudsen Mads Faurschou , Jacobsen Bo Holm , Seidenkrantz Marit-Solveig , Olsen Jesper
Published: February 2014

The Atlantic Multidecadal Oscillation (AMO) represents a significant driver of Northern Hemisphere climate, but the forcing mechanisms pacing the AMO remain poorly understood. Here we use the available proxy records to investigate the influence of solar and volcanic forcing on the AMO over the last ~450 years. The evidence suggests that external forcing played a dominant role in pacing the AMO after termination of the Little Ice Age (LIA; ca. 1400–1800), with an instantaneous impact on mid-latitude sea-surface temperatures that spread across the North Atlantic over the ensuing ~5 years. In contrast, the role of external forcing was more ambiguous during the LIA. Our study further suggests that the Atlantic Meridional Overturning Circulation is important for linking external forcing with North Atlantic sea-surface temperatures, a conjecture that reconciles two opposing theories concerning the origin of the AMO.
The modulation of grain boundary barrier in ZnMgO/ZnO heterostructure by surface polar liquid
Authors: Ji Xu , Zhu Yuan , Chen Mingming , Su Longxing , Chen Anqi , Gui Xuchun , Xiang Rong , Tang Zikang
Published: February 2014

Modulation of grain boundary barrier in ZnO layer by polar liquid, was investigated in ZnMgO/ZnO heterostructures grown by plasma-assisted molecular beam epitaxy. Traditionally, surface adsorbates can only affect the surface atoms or surface electronic states. However, it was found that the electronic conduction property of ZnO far from the surface could be tailored obviously by the polar liquid adsorbed on the ZnMgO surface. Physically, this phenomenon is supposed to be caused by the electrostatical couple between the liquid polarity and the grain boundary barrier in the ZnO layer through crystal polarization field.
Selective vancomycin detection using optical fibre long period gratings functionalised with molecularly imprinted polymer nanoparticles
Authors: Korposh Sergiy , Chianella Iva , Guerreiro Antonio , Caygill Sarah , Piletsky Sergey , James Stephen W. , Tatam Ralph P.
Published: February 2014

Molecularly imprinted polymer nanoparticles (nanoMIPs) were deposited onto an optical fibre long period grating (LPG) sensor for the first time with aim of the specific detection of antibiotics.
Development, evaluation and comparison of two independent sampling and analytical methods for ortho-phthalaldehyde vapors and condensation aerosols in air
Authors: Tucker Samuel P.
Published: February 2014

Two independent sampling and analytical methods for ortho-phthalaldehyde (OPA) in air have been developed, evaluated and compared: (1) a reagent-coated solid sorbent HPLC-UV method and (2) an impinger-fluorescence method.
Determination of triclocarban in aquatic plants by using SPE combined with HPLC-ESI-MS/MS
Authors: Miao Hong-Hao , Wang Yi-Nan , Zhao Ru-Song , Guo Wei-Lin , Wang Xia , Shen Ting-Ting , Wang Chen , Wang Xi-Kui
Published: February 2014

A convenient and reliable analytical method was developed for determination of antibacterial triclocarban in aquatic plants based on homogenate extraction, SPE clean-up, and HPLC-ESI-MS/MS determination.
Structural diversity and spectral and thermal properties of the first alkaline earth metal tetracyanidoborates: [Mg(H2O)6][B(CN)4]2, [Mg(H2O)2][B(CN)4]2, [Mg(DMF)6][B(CN)4]2, [Ca(H2O)3][B(CN)4]2, and [Ca(H2O)2(CH3CN)][B(CN)4]2
Authors: Nitschke Christian , Köckerling Martin , Bernhardt Eduard , Küppers Torsten , Willner Helge
Published: February 2014

The syntheses, structures, and spectral and thermal properties of the first tetracyanidoborate salts coordinating weakly to solvated alkaline earth cations are discussed.
Structural and redox requirements for the action of anti-diabetic vanadium compounds
Authors: Yoshikawa Yutaka , Sakurai Hiromu , Crans Debbie C. , Micera Giovanni , Garribba Eugenio
Published: February 2014

The transformation of non-oxido VIVto oxido VIVspecies under physiological conditions is necessary for a vanadium compound to exhibit pharmacological anti-diabetic activity.
Fast, energy-efficient synthesis of luminescent carbon quantum dots
Authors: Li Yongsheng , Zhong Xiaoxia , Rider Amanda E. , Furman Scott A. , Ostrikov Kostya (Ken)
Published: February 2014

A simple, fast, energy and labour efficient, carbon dot synthesis method involving only the mixing of a saccharide and base is presented.
Quantum dots on vertically aligned gold nanorod monolayer: plasmon enhanced fluorescence
Authors: Peng Bo , Li Zhenpeng , Mutlugun Evren , Hernández Martínez Pedro Ludwig , Li Dehui , Zhang Qing , Gao Yuan , Demir Hilmi Volkan , Xiong Qihua
Published: February 2014

A vertically aligned CTAB-coated Au nanorod monolayer was formed by the evaporation-induced self-assembly, which provides a unique anisotropic plasmonic system to investigate the energy transfer between the plasmonic array and fluorophores.
Solution-processed flexible transparent conductors based on carbon nanotubes and silver grid hybrid films
Authors: Wang Jing , Zhang Jintao , Sundramoorthy Ashok Kumar , Chen Peng , Chan-Park Mary B.
Published: February 2014

In a simple, cost-effective, and solution-based process, a thin-film of single-walled carbon nanotubes is hybridized on a PET film which has been patterned with solution self-assembled Ag nanoparticles.
Graphene-based hybrid structures combined with functional materials of ferroelectrics and semiconductors
Authors: Jie Wenjing , Hao Jianhua
Published: February 2014

Graphene-based hybrid systems combined with functional materials of ferroelectrics and semiconductors show various, fascinating and promising applications.
Chemistry teaching: Impact of educational research on the practices of chemistry teachers in Singapore
Authors: Tan Kim Chwee Daniel , Gilbert John K.
Published: February 2014

This paper reports the findings of a study which investigated the role that educational research plays in influencing 29 Singapore pre-university (Grades 11 and 12) and secondary (Grades 9 and 10) chemistry teachers' curricular and instructional decision making process. Twenty-five teachers were interviewed while four preferred to submit written responses to questions in the interview protocol. The findings indicated that factors which had an impact on the use of educational research by the teachers included those related to the teacher, school, research literature and time. This study can inform the chemistry educational research community of the issues that are important to teachers in their teaching of chemistry and use of educational research, and ways of working with teachers to address these issues.