bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous Detection of EGFR and VEGF in Colorectal Cancer using Fluorescence-Raman Endoscopy
Authors: Kim Yong-il , Jeong Sinyoung , Jung Kyung Oh , Song Myung Geun , Lee Chul-Hee , Chung Seock-jin , Park Ji Yong , Cha Myeong Geun , Lee Sung Gun , Jun Bong-Hyun , Lee Yun-Sang , Hwang Do Won , Youn Hyewon , Kang Keon Wook , Lee Yoon-Sik , Jeong Dae Hong , Lee Dong Soo
Published: April 2017

Fluorescence endomicroscopy provides quick access to molecular targets, while Raman spectroscopy allows the detection of multiple molecular targets. Using a simultaneous fluorescence-Raman endoscopic system (FRES), we herein demonstrate its potential in cancer diagnosis in an orthotopically induced colorectal cancer (CRC) xenograft model. In the model, epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) were targeted with antibody-conjugated fluorescence and surface-enhanced Raman scattering (F-SERS) dots. FRES demonstrated fast signal detection and multiplex targeting ability using fluorescence and Raman signals to detect the F-SERS dots. In addition, FRES showed a multiplex targeting ability even on a subcentimeter-sized CRC after spraying with a dose of 50 µg F-SERS dots. In conclusion, molecular characteristics of tumor cells (EGFR in cancer cell membranes) and tumor microenvironments (VEGF in the extracellular matrix) could be simultaneously investigated when performing a colonoscopy.
Structure-function analysis of the DNA-binding domain of a transmembrane transcriptional activator
Authors: Schlundt Andreas , Buchner Sophie , Janowski Robert , Heydenreich Thomas , Heermann Ralf , Lassak Jürgen , Geerlof Arie , Stehle Ralf , Niessing Dierk , Jung Kirsten , Sattler Michael
Published: April 2017

The transmembrane DNA-binding protein CadC of E. coli, a representative of the ToxR-like receptor family, combines input and effector domains for signal sensing and transcriptional activation, respectively, in a single protein, thus representing one of the simplest signalling systems. At acidic pH in a lysine-rich environment, CadC activates the transcription of the cadBA operon through recruitment of the RNA polymerase (RNAP) to the two cadBA promoter sites, Cad1 and Cad2, which are directly bound by CadC. However, the molecular details for its interaction with DNA have remained elusive. Here, we present the crystal structure of the CadC DNA-binding domain (DBD) and show that it adopts a winged helix-turn-helix fold. The interaction with the cadBA promoter site Cad1 is studied by using nuclear magnetic resonance (NMR) spectroscopy, biophysical methods and functional assays and reveals a preference for AT-rich regions. By mutational analysis we identify amino acids within the CadC DBD that are crucial for DNA-binding and functional activity. Experimentally derived structural models of the CadC-DNA complex indicate that the CadC DBD employs mainly non-sequence-specific over a few specific contacts. Our data provide molecular insights into the CadC-DNA interaction and suggest how CadC dimerization may provide high-affinity binding to the Cad1 promoter.
The effect of acute social stress on the recognition of facial expression of emotions
Authors: Daudelin-Peltier Camille , Forget Hélène , Blais Caroline , Deschênes Andréa , Fiset Daniel
Published: April 2017

This study investigates the effect of acute social stress on the recognition of facial expression of emotions in healthy young men. Participants underwent both a standardized psychosocial laboratory stressor (TSST-G) and a control condition. Then, they performed a homemade version of the facial expressions megamix. All six basic emotions were included in the task. First, our results show a systematic increase in the intensity threshold for disgust following stress, meaning that the participants’ performance with this emotion was impaired. We suggest that this may reflect an adaptive coping mechanism where participants attempt to decrease their anxiety and protect themselves from a socio-evaluative threat. Second, our results show a systematic decrease in the intensity threshold for surprise, therefore positively affecting the participants’ performance with that emotion. We suggest that the enhanced perception of surprise following the induction of social stress may be interpreted as an evolutionary adaptation, wherein being in a stressful environment increases the benefits of monitoring signals indicating the presence of a novel or threatening event. An alternative explanation may derive from the opposite nature of the facial expressions of disgust and surprise; the decreased recognition of disgust could therefore have fostered the propensity to perceive surprise.
Enteric innervation combined with proteomics for the evaluation of the effects of chronic fluoride exposure on the duodenum of rats
Authors: Melo Carina Guimarães de Souza , Perles Juliana Vanessa Colombo Martins , Zanoni Jacqueline Nelisis , Souza Sara Raquel Garcia de , Santos Erika Xavier , Leite Aline de Lima , Heubel Alessandro Domingues , e Souza Camila Oliveira , Souza Juliana Gadelha de , Buzalaf Marília Afonso Rabelo
Published: April 2017

Ingested fluoride (F) is absorbed mainly in the small intestine, which is controlled by the Enteric Nervous System (ENS). Although important intestinal symptomatology has been described after excessive F exposure, there have been no studies reporting the effects of F on the ENS. In this study, the effects of chronic F exposure were evaluated on the duodenums of rats through proteomic and morphological analyses. Concentrations of 0, 10, or 50 ppm of F were applied to the drinking water for 30 days. Immunofluorescence techniques were performed in the myenteric plexus of the duodenum to detect HuC/D, neuronal nitric oxide (nNOS), vasoactive intestinal peptide (VIP), calcitonin gene related peptide (CGRP), and substance P (SP). The 50 ppm F group presented a significant decrease in the density of nNOS-IR neurons. Significant morphological alterations were also observed in HUC/D-IR and nNOS-IR neurons; VIP-IR, CGRP-IR, and SP-IR varicosities for both groups (10 and 50 ppm F). Proteomic analysis of the duodenum demonstrated alterations in the expression of several proteins, especially those related to important biological processes, such as protein polymerization, which helps to explain the downregulation of many proteins upon exposure to 50 ppm of F.
Basal autophagy prevents autoactivation or enhancement of inflammatory signals by targeting monomeric MyD88
Authors: Into Takeshi , Horie Toshi , Inomata Megumi , Gohda Jin , Inoue Jun-ichiro , Murakami Yukitaka , Niida Shumpei
Published: April 2017

Autophagy, the processes of delivery of intracellular components to lysosomes, regulates induction of inflammation. Inducible macroautophagy degrades inflammasomes and dysfunctional mitochondria to downregulate inflammatory signals. Nonetheless, the effects of constitutive basal autophagy on inflammatory signals are largely unknown. Here, we report a previously unknown effect of basal autophagy. Lysosomal inhibition induced weak inflammatory signals in the absence of a cellular stimulus and in the presence of a nutrient supply, and their induction was impaired by MyD88 deficiency. During lysosomal inhibition, MyD88 was accumulated, and overabundant MyD88 autoactivated downstream signaling or enhanced TLR/IL-1R-mediated signaling. MyD88 is probably degraded via basal microautophagy because macroautophagy inhibitors, ATG5 deficiency, and an activator of chaperone-mediated autophagy did not affect MyD88. Analysis using a chimeric protein whose monomerization/dimerization can be switched revealed that monomeric MyD88 is susceptible to degradation. Immunoprecipitation of monomeric MyD88 revealed its interaction with TRAF6. In TRAF6-deficient cells, degradation of basal MyD88 was enhanced, suggesting that TRAF6 participates in protection from basal autophagy. Thus, basal autophagy lowers monomeric MyD88 expression, and thereby autoactivation of inflammatory signals is prevented. Given that impairment of lysosomes occurs in various settings, our results provide novel insights into the etiology of inflammatory signals that affect consequences of inflammation.
Multifunctional substrate of label-free electrochemical immunosensor for ultrasensitive detection of cytokeratins antigen 21-1
Authors: Wang Huiqiang , Gao Xin , Ma Zhanfang
Published: April 2017

Poly(thionine)-Au, a novel multifunctional substrate with excellent redox signal, enzyme-like activity, and easy antibody immobilisation, was synthesised using HAuCl4 as the oxidising agent and thionine as the monomer. The prepared poly(thionine)-Au composite exhibited an admirable electrochemical redox signal at −0.15 V and excellent H2O2 catalytic ability. In addition, gold nanoparticles in this composite were found to directly immobilise antibodies and further improve conductivity. In addition, a label-free electrochemical immunosensor was developed using poly(thionine)-Au as the sensing substrate for ultrasensitive detection of cytokeratin antigen 21-1 (CYFRA 21-1), an immunoassay found in human serum. The prepared immunosensor showed a wide liner range from 100 ng mL−1 to 10 fg mL−1 and an ultralow detection limit of 4.6 fg mL−1 (the ratio of signal to noise (S/N) = 3). Additionally, this method was used to analyse human serum samples and yielded results consistency with those of ELISA, implying its potential application in clinical research. The poly(thionine)-Au composite can be easily extended to other polymer-based nanocomposites, which is significant for other electrochemical immunoassays.
Three-dimensional resistivity and switching between correlated electronic states in 1T-TaS2
Authors: Svetin Damjan , Vaskivskyi Igor , Brazovskii Serguei , Mihailovic Dragan
Published: April 2017

Recent demonstrations of controlled switching between different ordered macroscopic states by impulsive electromagnetic perturbations in complex materials have opened some fundamental questions on the mechanisms responsible for such remarkable behavior. Here we experimentally address the question of whether two-dimensional (2D) Mott physics can be responsible for unusual switching between states of different electronic order in the layered dichalcogenide 1T-TaS2, or it is a result of subtle inter-layer “orbitronic” re-ordering of its stacking structure. We report on in-plane (IP) and out-of-plane (OP) resistance switching by current-pulse injection at low temperatures. Elucidating the controversial theoretical predictions, we also report on measurements of the anisotropy of the electrical resistivity "Equation missing""Equation missing"below room temperature. From the T-dependence of ρ⊥ and ρ||, we surmise that the resistivity is more consistent with collective motion than single particle diffusive or band-like transport. The relaxation dynamics of the metastable state for both IP and OP electron transport are seemingly governed by the same mesoscopic quantum re-ordering process. We conclude that 1T-TaS2 shows resistance switching arising from an interplay of both IP and OP correlations.
Inkjet printing-based volumetric display projecting multiple full-colour 2D patterns
Authors: Hirayama Ryuji , Suzuki Tomotaka , Shimobaba Tomoyoshi , Shiraki Atsushi , Naruse Makoto , Nakayama Hirotaka , Kakue Takashi , Ito Tomoyoshi
Published: April 2017

In this study, a method to construct a full-colour volumetric display is presented using a commercially available inkjet printer. Photoreactive luminescence materials are minutely and automatically printed as the volume elements, and volumetric displays are constructed with high resolution using easy-to-fabricate means that exploit inkjet printing technologies. The results experimentally demonstrate the first prototype of an inkjet printing-based volumetric display composed of multiple layers of transparent films that yield a full-colour three-dimensional (3D) image. Moreover, we propose a design algorithm with 3D structures that provide multiple different 2D full-colour patterns when viewed from different directions and experimentally demonstrate prototypes. It is considered that these types of 3D volumetric structures and their fabrication methods based on widely deployed existing printing technologies can be utilised as novel information display devices and systems, including digital signage, media art, entertainment and security.
Multi-state nonadiabatic deactivation mechanism of coumarin revealed by ab initio on-the-fly trajectory surface hopping dynamic simulation
Authors: Gan Yanzhen , Yue Ling , Guo Xugeng , Zhu Chaoyuan , Cao Zexing
Published: April 2017

An on-the-fly trajectory surface hopping dynamic simulation has been performed for revealing the multi-state nonadiabatic deactivation mechanism of coumarin.
Adamantane substitutions: a path to high-performing, soluble, versatile and sustainable organic semiconducting materials
Authors: Kovalenko Alexander , Yumusak Cigdem , Heinrichova Patricie , Stritesky Stanislav , Fekete Ladislav , Vala Martin , Weiter Martin , Sariciftci Niyazi Serdar , Krajcovic Jozef
Published: April 2017

Ethyladamantyl solubilization side groups were found to induce π−π interactions between the conjugated cores in soluble diketopyrrolopyrrole derivatives.
Correction: Rapid fabrication of functionalised poly(dimethylsiloxane) microwells for cell aggregate formation
Authors: Forget A. , Burzava A. L. S. , Delalat B. , Vasilev K. , Harding F. J. , Blencowe A. , Voelcker N. H.
Published: April 2017

Correction for ‘Rapid fabrication of functionalised poly(dimethylsiloxane) microwells for cell aggregate formation’ by A. Forget et al., Biomater. Sci., 2017, 5, 828–836.
An asymmetric vinylogous Mukaiyama–Michael reaction of α,β-unsaturated 2-acyl imidazoles catalyzed by chiral Sc(iii)– or Er(iii)–pybox complexes
Authors: Rout Subhrajit , Das Arko , Singh Vinod K.
Published: April 2017

A highly diastereo- and enantioselective vinylogous Mukaiyama–Michael reaction of silyloxyfurans with α,β-unsaturated 2-acyl imidazoles catalyzed by either chiral Sc(iii) or Er(iii) complexes of a pybox ligand has been reported.
Dissociation of cyclopropane in double ionization continuum
Authors: Oghbaie Shabnam , Gisselbrecht Mathieu , Månsson Erik P. , Laksman Joakim , Stråhlman Christian , Sankari Anna , Sorensen Stacey L.
Published: April 2017

The Jahn–Teller instability of cyclopropane contributes to dissociative double ionization processes.
Activation and deactivation of Ag/CeO2 during soot oxidation: influences of interfacial ceria reduction
Authors: Wang Houlin , Liu Shuang , Zhao Zhen , Zou Xin , Liu Minghan , Liu Wei , Wu Xiaodong , Weng Duan
Published: April 2017

Both the existence of CeO2 surface oxygen vacancies and their dynamic change during reaction may cause crucial influence on the soot oxidation behavior of Ag/CeO2.
A new mfj-type metal–organic framework constructed from a methoxyl derived V-shaped ligand and its H2, CO2 and CH4 adsorption properties
Authors: Du Liting , Lu Zhiyong , Xu Li , Zhang Jinchi
Published: April 2017

A new mfj-type microporous metal–organic framework exhibits high H2, CO2 and CH4 uptake capacities.
Recent developments in tetrathiafulvalene and dithiafulvalene based metal-free organic sensitizers for dye-sensitized solar cells: a mini-review
Authors: Duvva Naresh , Chilakamarthi Ushasri , Giribabu Lingamallu
Published: April 2017

Tetrathiafulvalene and dithiafulvalene are thermally stable, versatile and their HOMO–LUMO levels can be easily through molecular engineering to yield metal-free organic dyes for dye-sensitized solar cells, which are not restricted by the availability of natural resources.
Pomegranate-like CoO@nitrogen-doped carbon microspheres with outstanding rate behavior and stability for lithium storage
Authors: Liu Ge , Shao Jie
Published: April 2017

Pomegranate-like CoO@nitrogen-doped carbon microspheres, which exhibit outstanding rate behavior and stability for lithium storage, are rationally designed and prepared.
Ultrafine nano-sulfur particles anchored on in situ exfoliated graphene for lithium–sulfur batteries
Authors: Ma Zhaoling , Tao Li , Liu Dongdong , Li Zhen , Zhang Yiqiong , Liu Zhijuan , Liu Hanwen , Chen Ru , Huo Jia , Wang Shuangyin
Published: April 2017

Ultrafine sulfur/graphene composite was synthesized in one step with the assistance of DBD plasma and showed enhanced cycle life in Li–S batteries.
Ta-Doped SrCoO3−δ as a promising bifunctional oxygen electrode for reversible solid oxide fuel cells: a focused study on stability
Authors: Wang Jie , Yang Tianrang , Lei Libin , Huang Kevin
Published: April 2017

The present work reports a thorough investigation into the structural, thermal, electrical and electrochemical properties of 10 mol% Ta-doped SrCoO3−δ (denoted as SCT10) as a promising bifunctional oxygen electrode for intermediate-temperature reversible solid oxide fuel cells.
Flexible UV detector based on carbon fibers, ZnO nanorods, and Ag nanowires
Authors: Jang Geon , Jeong Lee Su , Lee Daewoo , Lee Dongwon , Lee Woong , Myoung Jae-Min
Published: April 2017

In a CF/ZnO NR composite structure, Ag NWs were deposited via spray-coating as a top electrode, which has good mechanical flexibility and optical transmittance to UV light.
Complementary hydrogen bonding interaction-mediated hole injection in organic light-emitting devices
Authors: Cheng Chih-Chia , Chu Chih-Wei , Huang Jyun-Jie , Liao Zhi-Sheng
Published: April 2017

Complementary nucleobase-functionalized conjugated polymers self-assemble to form supramolecular polymer networks that exhibit excellent thermal and hole-injection properties for the fabrication of high-performance multilayer OLED devices.
Molecular basis for the interaction between stress-inducible phosphoprotein 1 (STIP1) and S100A1
Authors: Maciejewski Andrzej , Prado Vania F. , Prado Marco A.M. , Choy Wing-Yiu
Published: April 2017

Stress-inducible phosphoprotein 1 (STIP1) is a cellular co-chaperone, which regulates heat-shock protein 70 (Hsp70) and Hsp90 activity during client protein folding. Members of the S100 family of dimeric calcium-binding proteins have been found to inhibit Hsp association with STIP1 through binding of STIP1 tetratricopeptide repeat (TPR) domains, possibly regulating the chaperone cycle. Here, we investigated the molecular basis of S100A1 binding to STIP1. We show that three S100A1 dimers associate with one molecule of STIP1 in a calcium-dependent manner. Isothermal titration calorimetry revealed that individual STIP1 TPR domains, TPR1, TPR2A and TPR2B, bind a single S100A1 dimer with significantly different affinities and that the TPR2B domain possesses the highest affinity for S100A1. S100A1 bound each TPR domain through a common binding interface composed of α-helices III and IV of each S100A1 subunit, which is only accessible following a large conformational change in S100A1 upon calcium binding. The TPR2B-binding site for S100A1 was predominately mapped to the C-terminal α-helix of TPR2B, where it is inserted into the hydrophobic cleft of an S100A1 dimer, suggesting a novel binding mechanism. Our data present the structural basis behind STIP1 and S100A1 complex formation, and provide novel insights into TPR module-containing proteins and S100 family member complexes.
Joint features and complementarities of Tspan8 and CD151 revealed in knockdown and knockout models
Authors: Yue Shijing , Zhao Kun , Erb Ulrike , Rana Sanyukta , Zöller Margot
Published: April 2017

Tetraspanins are highly conserved 4-transmembrane proteins which form molecular clusters with a large variety of transmembrane and cytosolic proteins. By these associations tetraspanins are engaged in a multitude of biological processes. Furthermore, tetraspanin complexes are located in specialized microdomains, called tetraspanin-enriched microdomains (TEMs). TEMs provide a signaling platform and are poised for invagination and vesicle formation. These vesicles can be released as exosomes (Exo) and are important in cell contact-independent intercellular communication. Here, we summarize emphasizing knockdown and knockout models' pathophysiological joint and selective activities of CD151 and Tspan8, and discuss the TEM-related engagement of CD151 and Tspan8 in Exo activities.
Atomic force microscopy of virus shells
Authors: Moreno-Madrid Francisco , Martín-González Natalia , Llauró Aida , Ortega-Esteban Alvaro , Hernando-Pérez Mercedes , Douglas Trevor , Schaap Iwan A.T. , de Pablo Pedro J.
Published: April 2017

Microscopes are used to characterize small objects with the help of probes that interact with the specimen, such as photons and electrons in optical and electron microscopies, respectively. In atomic force microscopy (AFM), the probe is a nanometric tip located at the end of a microcantilever which palpates the specimen under study just as a blind person manages a walking stick. In this way, AFM allows obtaining nanometric resolution images of individual protein shells, such as viruses, in a liquid milieu. Beyond imaging, AFM also enables not only the manipulation of single protein cages, but also the characterization of every physicochemical property capable of inducing any measurable mechanical perturbation to the microcantilever that holds the tip. In the present revision, we start revising some recipes for adsorbing protein shells on surfaces. Then, we describe several AFM approaches to study individual protein cages, ranging from imaging to spectroscopic methodologies devoted to extracting physical information, such as mechanical and electrostatic properties. We also explain how a convenient combination of AFM and fluorescence methodologies entails monitoring genome release from individual viral shells during mechanical unpacking.
Inspired by lipids: the Morton Lecture Award Presentation
Authors: Harwood John L.
Published: April 2017

Lipids are key molecules for membranes, energy storage and signalling. I have been privileged to have worked in such a diverse field and in organisms from microbes to humans. Here I will describe some of those contrasting areas which range from environmental impacts to food production and on to human health. It has been a fascinating journey which still continues to excite me.
An Approach to 3-Oxa-7-azabicyclo[3.3.0]octanes – Bicyclic Morpholine Surrogates
Authors: Grygorenko Oleksandr , Sokolenko Yevhenii , Ostapchuk Eugeniy , Artemenko Artem
Published: April 2017

An approach to 3-oxa-7-azabicyclo[3.3.0]octanes, bicyclic morpholine analogues, is reported, which relies on [3+2] cycloaddition of maleic anhydrides or furan-2(5H)-ones and an in situ generated azomethine ylide. The utility of the method was demonstrated on a multigram scale.
Effects of A One-week Fasting Therapy in Patients with Type-2 Diabetes Mellitus and Metabolic Syndrome – A Randomized Controlled Explorative Study
Authors: Li Chenying , Sadraie Badri , Steckhan Nico , Kessler Christian , Stange Rainer , Jeitler Michael , Michalsen Andreas
Published: April 2017

There is increasing experimental evidence for beneficial effects of calorie restriction and intermittent fasting in type 2 diabetes mellitus (T2DM). In humans, prolonged fasting is established as a health-promoting complementary treatment in Europe and claimed to improve metabolism by a complex hormetic response. We aimed to investigate effects of a one-week fasting period compared to usual care in T2DM by means of a pilot trial. Patients with manifest T2DM medically treated with oral hypoglycemic agents and/or insulin were randomly assigned to a 7-day fasting program followed by dietary advice or to usual care and dietary advice only. Fasting was performed according to the method of Buchinger with a nutritional energy intake of 300kcal/day by liquids only and stepwise re-introduction of solid food thereafter. Outcomes were assessed baseline and after 4 months. Of 46 enrolled participants, 32 (n=16 each group) completed the trial and were included for final analyses. Fasting was well accepted, there were no serious adverse events. After 4 months mean weight decreased by 3.5 kg and 2.0 kg in the fasting vs. control group (p=0.03) paralleled by greater reduction of abdominal circumference (p=0.001). Fasting led to a significant decrease of systolic/diastolic blood pressure (p=0.01; p=0.003) and increased quality-of-life (p=0.04), while for HbA1c, insulin and HOMA-index only non-significant improvements were observed. Results of this study suggest that prolonged fasting is feasible and might have beneficial clinical effects. The effectiveness of fasting should be proved in larger confirmatory trials that include intermittent fasting in follow-ups to enable more pronounced and long-term effects.
EFSUMB Guidelines and Recommendations on the Clinical Use of Liver Ultrasound Elastography, Update 2017 (Short Version)
Authors: Dietrich Christoph , Bamber Jeffrey , Berzigotti Annalisa , Bota Simona , Cantisani Vito , Castera Laurent , Cosgrove David , Ferraioli Giovanna , Friedrich-Rust Mireen , Gilja Odd , Goertz Ruediger , Karlas Thomas , de Knegt Robert , de Ledinghen Victor , Piscaglia Fabio , Procopet Bogdan , Saftoiu Adrian , Sidhu Paul , Sporea Ioan , Thiele Maja
Published: April 2017

We present here the first update of the 2013 EFSUMB (European Federation of Societies for Ultrasound in Medicine and Biology) Guidelines and Recommendations on the clinical use of elastography with a focus on the assessment of diffuse liver disease. The short version provides clinical information about the practical use of elastography equipment and interpretation of results in the assessment of diffuse liver disease and analyzes the main findings based on published studies, stressing the evidence from meta-analyses. The role of elastography in different etiologies of liver disease and in several clinical scenarios is also discussed. All of the recommendations are judged with regard to their evidence-based strength according to the Oxford Centre for Evidence-Based Medicine Levels of Evidence. This updated document is intended to act as a reference and to provide a practical guide for both beginners and advanced clinical users.
Sensitivity of hydrothermal wave instability of Marangoni convection to the interfacial heat transfer in long liquid bridges of high Prandtl number fluids
Authors: Yano T. , Nishino K. , Ueno I. , Matsumoto S. , Kamotani Y.
Published: April 2017

This paper reports the sensitivity of hydrothermal wave (HTW) instability of Marangoni convection to the interfacial heat transfer in liquid bridges (LBs) of high Prandtl number fluids (Pr = 67, 112, and 207) formed under the microgravity environment on the International Space Station. The data for instability are collected for a wide range of AR and for TC = 15 and 20 °C, where AR is the aspect ratio (=height/diameter) of the LB and TC is the cooled disk temperature. A significant decrease in critical oscillation frequency as well as an appreciable decrease in the critical Marangoni number is observed for AR > 1.25. This drastic change of instability mechanisms is associated with the reversal of axial traveling direction of HTWs and roll-structures as reported previously. It is found that this reversal is closely related to the interfacial heat transfer, which is evaluated numerically through accounting for both convective and radiative components. A heat transfer ratio, QI/QH, is introduced as a dimensionless parameter for interfacial heat transfer, where QI and QH are the heat transfer rates at the LB-gas and LB-heated disk interfaces, respectively. It is found that HTWs travel in the same direction as the surface flow for QI/QH > 0 (heat-loss condition) while in the opposite direction for QI/QH < 0 (heat-gain condition) in the present microgravity experiment. It is shown that the heat-transfer condition alters slightly but appreciably the basic temperature and flow field, the alteration that is not accounted for in the previous linear stability analyses for an infinite LB.
Solution of cavity resonance and waveguide scattering problems using the eigenmode projection technique
Authors: Nasr Mamdouh H. , Othman Mohamed A. K. , Eshrah Islam A. , Abuelfadl Tamer M.
Published: April 2017

New developments in the eigenmode projection technique (EPT) are introduced in solving problems of electromagnetic resonance in closed cavities as well as scattering from discontinuities in guided-wave structures. The EPT invokes the eigenmodes of a canonical predefined cavity in the solution procedure and uses the expansion of these eigenmodes to solve Maxwell's equations, in conjunction with a convenient choice of port boundary conditions. For closed cavities, a new spurious-mode separation method is developed, showing robust and efficient spurious-mode separation. This has been tested using more complex and practical examples demonstrating the powerful use of the presented approach. For waveguide scattering problems, convergence studies are being performed showing stable solutions for a relatively small number of expansion modes, and the proposed method has advantages over conventional solvers in analyzing electromagnetic problems with inhomogeneous materials. These convergence studies also lead to an efficient rule-of-thumb for the number of modes to be used in the simulation. The ability to handle closed and open structures is presented in a unified framework that highlights the generality of the EPT which could be used to analyze and design a variety of microwave components.
Small static electric field strength promotes aggregation-prone structures in amyloid-β(29-42)
Authors: Lu Yan , Shi Xiao-Feng , Salsbury Freddie R. , Derreumaux Philippe
Published: April 2017

The formation of senile plaques in central neural system resulting from the aggregation of the amyloid β (Aβ) of 40 and 42 residues is one of the two hallmarks of Alzheimer’s disease. Numerous experiments and computational studies have shown that the aggregation of Aβ peptides in vitro is very complex and depends on many factors such as pH, agitation, temperature, and peptide concentration. The impact of a static electric field (EF) on amyloid peptide aggregation has been much less studied, although EFs may have some applications to treat Parkinson’s disease symptoms. Here, we study the influence of an EF strength of 20 mV/nm, present in the human brains, on the conformation of the Aβ29–42 dimer. Our 7 μs non-equilibrium atomistic simulations in aqueous solution show that this field-strength promotes substantially the formation of β-hairpins, believed to be a very important intermediate state during aggregation. This work also suggests that structural biology experiments conducted under appropriate EF strengths may help reduce the conformational heterogeneity of Aβ1–40/Aβ1–42 dimers and provide significant insights into their structures that may be disease-causing.
Correlated natural transition orbitals for core excitation energies in multilevel coupled cluster models
Authors: Høyvik Ida-Marie , Myhre Rolf Heilemann , Koch Henrik
Published: April 2017

In this article, we present a black-box approach for the selection of orbital spaces when computing core excitation energies in the multilevel coupled cluster (MLCC) framework. Information available from the lower level of theory is used to generate correlated natural transition orbitals (CNTOs) for the high-level calculation by including both singles and doubles information in the construction of the transition orbitals. The inclusion of the doubles excitation information is essential to obtain a set of orbitals that all contain physical information, in contrast to the natural transition orbitals where only a small subset of the virtual orbitals contains physical information. The CNTOs may be included in an active space based on a cutoff threshold for the eigenvalues corresponding to the orbitals. We present MLCC results for core excitation energies calculated using coupled cluster singles and doubles (CCSD) in the inactive space and CCSD with perturbative triples (CC3) in the active space. The use of CNTOs results in small errors compared to full CC3.
Design dopamine-modified polypropylene fibers towards removal of heavy metal ions from water
Authors: Liu K. , Zhou N. Y. , Xie C. X. , Mou B. , Ai Y. N.
Published: April 2017

A simple approach to preparing dopamine-modified polypropylene fibers with a controllable polydopamine amount is supplied. By the dopamine modification, the hydrophobic polypropylene fibers have been changed into hydrophilic. The hydrophilicity can be improved by increasing the amount of polydopamine, as revealed by the contact angle evolutions. The hydrophilic dopamine-modified polypropylene fibers can rapidly and effectively remove copper and lead ions in water. Moreover, the performance of removing heavy metals is prominently improved as the polydopamine amount increases. This is because the polydopamine introduction can supply many available sites for adsorbing heavy metal ions, as revealed by theoretical simulation results. These results are crucial in future engineering fiber filters towards efficiently removing heavy metal ions using dopamine-modified polypropylene fibers.
Research Update: Nanogenerators for self-powered autonomous wireless
sensors
Authors: Khan Usman , Hinchet Ronan , Ryu Hanjun , Kim Sang-Woo
Published: April 2017

Largely distributed networks of sensors based on the small electronics have great potential for health care, safety, and environmental monitoring. However, in order to have a maintenance free and sustainable operation, such wireless sensors have to be self-powered. Among various energies present in our environment, mechanical energy is widespread and can be harvested for powering the sensors. Piezoelectric and triboelectric nanogenerators (NGs) have been recently introduced for mechanical energy harvesting. Here we introduce the architecture and operational modes of self-powered autonomous wireless sensors. Thereafter, we review the piezoelectric and triboelectric NGs focusing on their working mechanism, structures, strategies, and materials.
Non-linear coherent structures of kinetic Alfvén waves in plasmas with non-Maxwellian electrons and their relevance for space plasmas
Authors: Devi Nirupama , Chaharia Rumi
Published: April 2017

The existence of Kinetic Alfvén waves (KAWs) in two-fluid plasma dominated by non-Maxwellian electrons has been investigated. Arbitrary amplitude Solitary Kinetic Alfvén waves (SKAWs) and Double Layers (DLs) are developed. Parameter ranges for Plasma Beta, Mach number are seen to vary from higher to lower values in the transition of propagation from DLs with net potential drop to SKAWs showing energetic tailing structures in the whole process. Such phenomena change the energy level in space plasma regions because of the presence of the non-Maxwellian electrons possessing relevant kappa index values. The Sagdeev potential shows that the enhanced level of energy of the waves is higher when the direction of propagation of the waves is nearer to the ambient magnetic field direction.
QED effects in 1s and 2s single and double ionization potentials of the noble gases
Authors: Niskanen J. , Jänkälä K. , Huttula M. , Föhlisch A.
Published: April 2017

We present calculations on the quantum electrodynamics (QED) effects in 1s and 2s single and double ionization potentials of noble gases from Ne to Rn as perturbations on relativistic four-component Dirac-Fock wavefunctions. The most dominant effect originates from the self-energy of the core-electron that yields corrections of similar order as the transverse interaction. For 1s ionization potentials, a match within few eV against the known experimental values is obtained, and our work reveals considerable QED effects in the photoelectron binding energies across the periodic table—most strikingly even for Ne. We perform power-law fits for the corrections as a function of Z and interpolate the QED correction of ∼−0.55 eV for S1s. Due to this, the K-edge electron spectra of the third row and below need QED for a match in the absolute energy when using state-of-the-art instrumentation.
Nonlinear parametric resonance of relativistic electrons with a linearly polarized laser pulse in a plasma channel
Authors: Huang T. W. , Zhou C. T. , Robinson A. P. L. , Qiao B. , Arefiev A. V. , Norreys P. A. , He X. T. , Ruan S. C.
Published: April 2017

The direct laser-acceleration mechanism, nonlinear parametric resonance, of relativistic electrons in a linearly polarized laser-produced plasma channel is examined by a self-consistent model including the relativistic laser dispersion in plasmas. Nonlinear parametric resonance can be excited, and the oscillation amplitude of electrons grows exponentially when the betatron frequency of electron motion varies roughly twice the natural frequency of the oscillator. It is shown analytically that the region of parametric resonance is defined by the self-similar parameter nenca0. The width of this region decreases with nenca0, but the energy gain and oscillation amplitude increases. In this regime, the electron transverse momentum grows faster than that in the linear classical resonance regime.
PIC simulations of conical magnetically insulated transmission line with LTD generator: Transition from self-limited to load-limited flow
Authors: Liu Laqun , Wang Huihui , Guo Fan , Zou Wenkang , Liu Dagang
Published: April 2017

Based on the 3-dimensional Particle-In-Cell (PIC) code CHIPIC3D, with a new circuit boundary algorithm we developed, a conical magnetically insulated transmission line (MITL) with a 1.0-MV linear transformer driver (LTD) is explored numerically. The values of switch jitter time of LTD are critical parameters for the system, which are difficult to be measured experimentally. In this paper, these values are obtained by comparing the PIC results with experimental data of large diode-gap MITL. By decreasing the diode gap, we find that all PIC results agree well with experimental data only if MITL works on self-limited flow no matter how large the diode gap is. However, when the diode gap decreases to a threshold, the self-limited flow would transfer to a load-limited flow. In this situation, PIC results no longer agree with experimental data anymore due to the anode plasma expansion in the diode load. This disagreement is used to estimate the plasma expansion speed.
Photoinduced coherent acoustic phonon dynamics inside Mott insulator Sr2IrO4 films observed by femtosecond X-ray pulses
Authors: Zhang Bing-Bing , Liu Jian , Wei Xu , Sun Da-Rui , Jia Quan-Jie , Li Yuelin , Tao Ye
Published: April 2017

We investigate the transient photoexcited lattice dynamics in a layered perovskite Mott insulator Sr2IrO4 film by femtosecond X-ray diffraction using a laser plasma-based X-ray source. The ultrafast structural dynamics of Sr2IrO4 thin films are determined by observing the shift and broadening of (0012) Bragg diffraction after excitation by 1.5 eV and 3.0 eV pump photons for films with different thicknesses. The observed transient lattice response can be well interpreted as a distinct three-step dynamics due to the propagation of coherent acoustic phonons generated by photoinduced quasiparticles (QPs). Employing a normalized phonon propagation model, we found that the photoinduced angular shifts of the Bragg peak collapse into a universal curve after introducing normalized coordinates to account for different thicknesses and pump photon energies, pinpointing the origin of the lattice distortion and its early evolution. In addition, a transient photocurrent measurement indicates that the photoinduced QPs are charge neutral excitons. Mapping the phonon propagation and correlating its dynamics with the QP by ultrafast X-ray diffraction (UXRD) establish a powerful way to study electron-phonon coupling and uncover the exotic physics in strongly correlated systems under nonequilibrium conditions.
Combined intrinsic elastocaloric and electrocaloric properties of ferroelectrics
Authors: Khassaf H. , Patel T. , Alpay S. P.
Published: April 2017

In multiferroic materials, adiabatic temperature changes can be obtained by the combined application of electric, stress, and magnetic fields. These external stimuli provide additional channels of entropy variations resulting in a multi-caloric response. In ferroelectric (FE) materials, caloric responses can be obtained with the application of electric and mechanical fields. Here, we compute the intrinsic elastocaloric and stress–mediated electrocaloric behavior of prototypical FE materials using the Landau–Devonshire theory of phase transformations with appropriate electrical and electro–mechanical boundary conditions. We show that an elastocaloric adiabatic temperature variation of 12.7 °C can be obtained in PbTiO3 with the application of uniaxial tensile stress of 500 MPa near its Curie point. This is 59% higher than its pure intrinsic electrocaloric response for an electric field difference of 100 kV/cm. Moreover, external stresses allow the maximum electro–elastocaloric response to be tuned towards room temperature. Our calculations show that relaxor FEs should exhibit large adiabatic temperature variations in relatively broad temperature ranges. These findings indicate that caloric responses in ferroic materials can be deterministically controlled and enhanced by utilizing a variety of external stimuli.
Electrically tuned photoelectrochemical properties of ferroelectric nanostructure NaNbO3 films
Authors: Singh Simrjit , Khare Neeraj
Published: April 2017

Photoelectrochemical (PEC) properties of NaNbO3 nanostructure ferroelectric films are investigated, and it is demonstrated that the efficiency of PEC water splitting can be tuned (7%–23%) by electrical polarization of the NaNbO3 films. The NaNbO3 photoelectrode is fabricated using hydrothermally synthesized NaNbO3 nanoparticles. Compared to the as-prepared photoanode, photocurrent is enhanced from 0.31 to 0.51 mA/cm2 (at 1 V vs. Ag/AgCl) for the negatively polarized NaNbO3 film, whereas the photocurrent is found to decrease from 0.31 to 0.09 mA/cm2 for the positively polarized NaNbO3 film. The change in the photoelectrochemical activity after the polarization of NaNbO3 films has been attributed to the change in the conduction/valence band bending at the semiconductor/electrolyte interface, leading to a change in the efficiency of charge transfer at the interface. Mott-Schottky studies confirmed the change in band bending after polarization, and electrochemical impedance spectroscopy studies confirmed the modulation in the charge transfer process after polarization.
Chemical pressure effect in Sm and La substituted ferroelectric BiFeO3 thin films: Insights from infrared spectroscopy
Authors: Burkert F. , Janowski M. , Zhang X. , Takeuchi I. , Kuntscher C. A.
Published: April 2017

We investigate the effects of Sm and La substitution in ferroelectric BiFeO3 thin films on the lattice dynamics by infrared reflection measurements at room temperature. The frequencies of the infrared-active phonon modes are studied as a function of Sm and La content in Bi1–x(Sm,La)xFeO3 composition spread films in the range from x = 0 up to x = 0.25, grown on SrTiO3 substrates by pulsed laser deposition. Substitution of the Bi3+ ions with small Sm3+ ions leads to the appearance of a new phase above x ≈ 0.09 coexisting with the ferroelectric BiFeO3 phase up to x ≈ 0.19. In contrast, for the substitution of Bi3+ ions with La3+ ions of similar size a continuous transition from the original BiFeO3 phase to a new phase takes place. In both cases, we assign the new phase to the paraelectric, orthorhombic phase. These findings are discussed in terms of the morphotropic phase boundary in Sm-doped BiFeO3 around x = 0.14 with a phase coexistence, which was suggested as the origin for enhanced piezoelectric properties.
Fabrication of high-quality GaAs-based photodetector arrays on Si
Authors: Kim SangHyeon , Geum Dae-Myeong , Park Min-Su , Kim Ho-sung , Song Jin Dong , Choi Won Jun
Published: April 2017

We report on fabrication and characterization of high-quality 32 × 32 GaAs photodetector (PD) arrays on Si substrates fabricated by wafer bonding and epitaxial lift-off (ELO) techniques. Fabricated GaAs PD arrays showed good crystal quality on Si substrates with Raman spectra and X-ray diffraction measurement. Also, pitch scaling gave us faster ELO process time as well as high-density PD arrays. Furthermore, we investigated electrical and optical characteristics of fabricated GaAs pin PD arrays on Si substrates. Especially, the components of dark current characteristics were also evaluated, because it is very important to explore further pitch scaling.
Effect of non-Maxwellian electrons on shear flow modified ion acoustic solitons
Authors: Shafiq Ammara , Ali Shan S. , Saleem H.
Published: April 2017

Dynamics of shear flow modified ion acoustic wave is investigated assuming electrons to follow q-nonextensive and Cairns distribution functions. A modified linear dispersion relation and electrostatic KdV solitons are analyzed. Results are illustrated considering solar wind and F-region ionospheric plasmas. Effects of non-Maxwellian distribution of electrons on the amplitude and the width of solitons are pointed out in the presence of field-aligned inhomogeneous flow.
Efficient shock drift acceleration in the collision of two asymmetric pair plasma shells
Authors: Li R. , Zhou C. T. , Huang T. W. , Qiao B. , He X. T.
Published: April 2017

The shock drift acceleration (SDA) process in the collision between two asymmetric relativistic pair plasma shells was investigated. It is found that the density ratio (nL/nR) of the two different plasma shells plays a crucial role in the SDA process and determines the efficiency of the SDA process. By increasing this parameter, the plasma bulk velocity and so as to the convection electric field in the downstream region can be much enhanced compared with the symmetric case, in which the densities in the two plasma shells are the same. As a result, the particles are efficiently accelerated by the large convection electric field and the efficiency of the SDA process is much increased as the density ratio is increased. Our particle-in-cell simulations demonstrate that the SDA efficiency can be improved by three to four times in the asymmetric case. In this way, more high energy particles could enter into the phase of the diffusive shock acceleration process.
The egg coat zona pellucida 3 glycoprotein – evolution of its putative sperm-binding region in Old World murine rodents (Rodentia: Muridae)
Authors: Swann Christine A. , Cooper Steven J. B. , Breed William G.
Published: April 2017

In eutherian mammals, before fertilisation can occur the spermatozoon has to bind to, and penetrate, the egg coat, the zona pellucida (ZP). In the laboratory mouse there is good evidence that the primary sperm-binding site is a protein region encoded by Exon 7 of the ZP3 gene and it has been proposed that binding is species specific and evolves by sexual selection. In the present study we investigate these hypotheses by comparing Exon 6 and 7 sequences of ZP3 in 28 species of murine rodents of eight different divisions from Asia, Africa and Australasia, in which a diverse array of sperm morphologies occurs. We found considerable nucleotide (and corresponding amino acid) sequence divergence in Exon 7, but not in Exon 6, across these species, with evidence for positive selection at five codon positions. This molecular divergence does not appear to be due to reinforcement to reduce hybridisation, nor does it correlate with divergence in sperm head morphology or tail length, thus it is unlikely to be driven by inter-male sperm competition. Other forms of post-copulatory sexual selection therefore appear to have resulted in the molecular divergence of this region of ZP3 in this highly speciose group of mammals.