bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrospinning of poly(lactic acid): Theoretical approach for the solvent selection to produce defect‐free nanofibers
Authors: Casasola Raffaella , Thomas Noreen L. , Georgiadou Stella
Published: March 2016

In this study an integrated methodology was proposed for the selection of solvent systems to produce electrospinnable solutions that form defect‐free poly(lactic acid) (PLA) fibers with narrow diameter distributions. The solvent systems were chosen using a thermodynamic approach, combined with electrical and rheological property criteria. More specifically, the three step methodology includes (1) initial choice of solvent by solubility evaluation to meet thermodynamic criteria, (2) electrical properties, that is, conductivity and dielectric constant adjustment by using solvent mixtures to meet electrical property criteria, and (3) critical entanglement concentration (Ce) determination by viscosity measurements, supported by elastic and plastic moduli measurements, followed by concentration adjustment to meet rheological criteria. All three criteria need to be met to ensure defect‐free nanofiber morphology. The methodology was demonstrated using PLA solutions that were characterized in terms of thermodynamic properties, conductivity, surface tension, and viscosity measurements. These data were analyzed and related to the nanofiber morphology and diameter as determined from scanning electron microscopy (SEM). Measurements of the elastic (G′) and the plastic (G″) moduli of PLA solutions showed a sharp increase of G′ at the chain entanglement concentration. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2016,54, 1483–1498
Auxiliary Part of Ligand Mediated Unique Coordination Chemistry of Copper (II)
Authors: Majumder Ishani , Chakraborty Prateeti , Adhikary Jaydeep , Kara Hulya , Zangrando Ennio , Bauza Antonio , Frontera Antonio , Das Debasis
Published: March 2016

Six N,N,O‐donor Schiff‐base ligands, HL1‐HL6, [HL1/HL2/HL3={2‐(2‐piperazin‐1‐yl)ethylimino)methyl)‐4‐(Cl/H/Me)‐phenol}; HL4/HL5/HL6={2‐(2‐morpholine/piperidine/ pyrrolidine −1‐yl)ethylimino)methyl)‐4‐chlorophenol}, have been designed by combining 5‐R‐2‐hydroxy‐benzaldehyde, (R=Cl/H/Me) and N‐(2‐aminoethyl)‐Y, (Y=piperazin/morpholine/ piperidine/pyrrolidine) with the view to explore the role of R and X (part of Y excluding coordinating N) on the coordination chemistry of Cu(II) in presence of bromide as counter anion. HL1‐HL6 formed in situ on reaction with Cu(II)Br2 produce complexes 1–6, respectively. Complex 1, [Cu(II)2Cu(I)2(L1)(MeOH)2Br7.30], is a mixed valence Cu(I)‐Cu(II) species having phenyl ring brominated at ortho position with 0.65 occupancy. Complexes 2–4 are mononuclear species with general formula [Cu{L2/L3/L4)}Br2]. Complexes [Cu3(L5)Br4] (5) and [Cu3(L6)Br4] (6) are trinuclear species having similar structure but exhibit different magnetic property, 5 is ferro‐ (J= +16.64 cm−1 ) and 6 is antiferromegnetic (J=–11.76 cm−1). The influence of R and X on bromonation, magnetic property and nuclearity issues have been rationalized by DFT calculations.
C–N cross coupling approach synthesis and electronic properties of donor–acceptor oligomer
Authors: Kundu Rajen , Kulshreshtha Chandramouli
Published: March 2016

C–N cross coupling approach synthesis of donor–acceptor oligomer containing 9,9‐dioctyl‐N2,N7‐diaryl‐9H‐fluorene‐2,7‐diamine and 5‐octyl‐1,3‐di(thiophen‐2‐yl)‐4H‐thieno[3,4‐c]pyrrole‐4,6(5H)‐dione has been reported. The electronic properties of the synthesized oligomers were studied by UV‐visible spectroscopy, fluorescence spectroscopy, cyclic voltammetry and computational analysis. The oligomers absorb the visible light at around 508–520 nm, both in solution as well as in solid state. We observed dual emission band centred at around 595 nm (LE emission) and 650 nm (CT emission) with a long tail in near‐infrared (NIR) spectral region when the oligomers were excited at around 510 nm. Large Stokes shifts (∼130 nm) led to deep red emission which was likely due to the interaction of donor–acceptor units of the oligomer backbone. Overall, the experimental and theoretical results of these oligomers indicate that they can be used as a promising materials for organic electronics.
Are founder CEOs more overconfident than professional CEOs? Evidence from S&P 1500 companies
Authors: Lee Joon Mahn , Hwang Byoung‐Hyoun , Chen Hailiang
Published: March 2016

Research summary: We provide evidence that founder chief executive officers (CEOs) of large S&P 1500 companies are more overconfident than their nonfounder counterparts (“professional CEOs”). We measure overconfidence via tone of CEO tweets, tone of CEO statements during earnings conference calls, management earnings forecasts, and CEO option‐exercise behavior. Compared with professional CEOs, founder CEOs use more optimistic language on Twitter and during earnings conference calls. In addition, founder CEOs are more likely to issue earnings forecasts that are too high; they are also more likely to perceive their firms to be undervalued, as implied by their option‐exercise behavior. We provide evidence that, to date, investors appear unaware of this “overconfidence bias” among founders.

Managerial summary: This article helps to explain why firms managed by founder chief executive officers (CEOs) behave differently from those managed by professional CEOs. We study a sample of S&P 1500 firms and find strong evidence that founder CEOs are more overconfident than professional CEOs. To date, investors appear unaware of this overconfidence bias among founders. Our study should help firm stakeholders, including investors, employees, suppliers, and customers, put the statements and actions of founder CEOs in perspective. Our study should also help members of corporate boards make more informed decisions about whether to retain (or bring back) founder CEOs or hire professional CEOs. Copyright © 2016 John Wiley & Sons, Ltd.
The recent history and successes of China's energy efficiency policy
Authors: Yang Mian , Hu Zheng , Yuan Jiahai
Published: March 2016

Energy conservation has been a critical argument in China's development agenda for decades. China had 8 billion tons of greenhouse gas (GHG) emission in 2012 (shared 27% of total global GHG emission), which received attention from researchers at home and abroad. This paper summarizes China's major policy development pathway on energy efficiency since the 1978 open‐door policy. The major focuses of this paper are provided from the perspectives of building energy efficiency capacity and reducing long‐term energy intensity as well as accelerating China's economic transformation. According to the characteristics of economic development phases, energy efficiency policy improvement in the past 35 years could be divided into three categories: planned economic period (1978–1991), partial market economic period (1992–2002) and technology‐oriented economic transformation period (2003‐present). This paper also recommends China's future energy efficiency plan to enable a long‐term energy conservation mechanism, particularly to place a close emphasis on economic transformations. WIREs Energy Environ 2016, 5:715–730. doi: 10.1002/wene.213

This article is categorized under:

Energy Policy and Planning > Economics and Policy

Energy Policy and Planning > Systems and Infrastructure

Energy Policy and Planning > Climate and Environment
Intestinal ileus and pneumatosis intestinalis as the major manifestations of tuberculous peritonitis: A diagnostic challenge
Authors: Chen Chang‐Hua , Chou Kun‐Ching , Tsao Lien‐Cheng
Published: March 2016

Tuberculous peritonitis (TBP) is a continuing problem in populations with high prevalence of tuberculosis and is difficult to diagnose early. Here, we report a case of confirmed TBP that presented as intestinal ileus and pneumatosis intestinalis. The 79‐year‐old woman had a history of atrial fibrillation, chronic ischemic heart disease, and chronic renal failure (chronic kidney disease, stage V). She complained of abdominal fullness and pain for 1 week prior to hospitalization. A computed tomography (CT) scan revealed pneumatosis intestinalis. Laparoscopic surgery was performed, and multiple whitish nodules covering the peritoneum were discovered. Biopsy results were consistent with caseating granulomatous inflammation. A modified anti‐tuberculosis regimen (isoniazid, 300 mg daily; rifampicin 600 mg daily; ethambutol 800 mg three times per week; and pyrazinamide 1200 mg three times per week) was initiated, stabilizing the condition of the patient. The total duration of anti‐tuberculosis therapy was 12 months, with patient condition gradually improving to normal. The elderly, uremic patients recovered fully after the modified anti‐tuberculosis regimen for 12 months. For clinical practice, we developed a decision‐making algorithm for patients suspecting TBP.
The effects of experimental pain and induced optimism on working memory task performance
Authors: Boselie Jantine J.L.M. , Vancleef Linda M.G. , Peters Madelon L.
Published: March 2016

Background/aims

Pain can interrupt and deteriorate executive task performance. We have previously shown that experimentally induced optimism can diminish the deteriorating effect of cold pressor pain on a subsequent working memory task (i.e., operation span task). In two successive experiments we sought further evidence for the protective role of optimism on pain-induced working memory impairments. We used another working memory task (i.e., 2-back task) that was performed either after or during pain induction.

Methods

Study 1 employed a 2 (optimism vs. no-optimism) × 2 (pain vs. no-pain) × 2 (pre-score vs. postscore) mixed factorial design. In half of the participants optimism was induced by the Best Possible Self (BPS) manipulation, which required them to write and visualize about a life in the future where everything turned out for the best. In the control condition, participants wrote and visualized a typical day in their life (TD). Next, participants completed either the cold pressor task (CPT) or a warm water control task (WWCT). Before (baseline) and after the CPT or WWCT participants working memory performance was measured with the 2-back task. The 2-back task measures the ability to monitor and update working memory representation by asking participants to indicate whether the current stimulus corresponds to the stimulus that was presented 2 stimuli ago. Study 2 had a 2 (optimism vs. no-optimism) × 2 (pain vs. no-pain) mixed factorial design. After receiving the BPS or control manipulation, participants completed the 2-back task twice: once with painful heat stimulation, and once without any stimulation (counterbalanced order). Continuous heat stimulation was used with temperatures oscillating around 1 °C above and 1 °C below the individual pain threshold.

Results

In study 1, the results did not show an effect of cold pressor pain on subsequent 2-back task performance. Results of study 2 indicated that heat pain impaired concurrent 2-back task performance. However, no evidence was found that optimism protected against this pain-induced performance deterioration.

Conclusions

Experimentally induced pain impairs concurrent but not subsequent working memory task performance. Manipulated optimism did not counteract pain-induced deterioration of 2-back performance.

Implications

It is important to explore factors that may diminish the negative impact of pain on the ability to function in daily life, as pain itself often cannot be remediated. We are planning to conduct future studies that should shed further light on the conditions, contexts and executive operations for which optimism can act as a protective factor.
Looking; looking back
Authors: Craig James A. , Ozga-Lawn Matthew
Published: March 2016

Architectural representation – concerned as it is with things at levels of abstraction, scales of ‘bigness’, and already complex, intertwined and multi-layered contexts – often overlooks or presupposes the seemingly straightforward attributes of its engagement. Acts of looking at (or into) architectural imagery, objects and other phenomena are principally concerned with the spaces held within, rather than asking us to reflect on the experience of interacting with the representational device itself. In this way, architectural imagery attempts to mask its own presence. By always gesturing to the thing that is distant or unbuilt, it asks us, perversely, to pretend that it isn't there – that we are in fact engaging directly with the spaces and structures depicted rather than their likenesses in paper, card or otherwise. Our own practice (STASUS) and teaching concerns itself with the relationship between the observer and the architectural project, and the complex set of coded meanings which are engaged with in this encounter. We are particularly interested in the affecting nature of the space in which design processes are undertaken. In this paper, we reflect on the experience of encountering architectural projects through their representation, both in a state of completion and in process. We set out to reframe an idea of architectural design as the performance of a dialogue between recognisable, image-able things, held and staged by objects and media that don't meet or exceed expectations, but defy them, by demanding to be noticed.
Glycerol-3-phosphate acyltransferase-1 upregulation by O-GlcNAcylation of Sp1 protects against hypoxia-induced mouse embryonic stem cell apoptosis via mTOR activation
Authors: Lee H J , Ryu J M , Jung Y H , Lee K H , Kim D I , Han H J
Published: March 2016

Oxygen signaling is critical for stem cell regulation, and oxidative stress-induced stem cell apoptosis decreases the efficiency of stem cell therapy. Hypoxia activates O-linked β-N-acetyl glucosaminylation (O-GlcNAcylation) of stem cells, which contributes to regulation of cellular metabolism, as well as cell fate. Our study investigated the role of O-GlcNAcylation via glucosamine in the protection of hypoxia-induced apoptosis of mouse embryonic stem cells (mESCs). Hypoxia increased mESCs apoptosis in a time-dependent manner. Moreover, hypoxia also slightly increased the O-GlcNAc level. Glucosamine treatment further enhanced the O-GlcNAc level and prevented hypoxia-induced mESC apoptosis, which was suppressed by O-GlcNAc transferase inhibitors. In addition, hypoxia regulated several lipid metabolic enzymes, whereas glucosamine increased expression of glycerol-3-phosphate acyltransferase-1 (GPAT1), a lipid metabolic enzyme producing lysophosphatidic acid (LPA). In addition, glucosamine-increased O-GlcNAcylation of Sp1, which subsequently leads to Sp1 nuclear translocation and GPAT1 expression. Silencing of GPAT1 by gpat1 siRNA transfection reduced glucosamine-mediated anti-apoptosis in mESCs and reduced mammalian target of rapamycin (mTOR) phosphorylation. Indeed, LPA prevented mESCs from undergoing hypoxia-induced apoptosis and increased phosphorylation of mTOR and its substrates (S6K1 and 4EBP1). Moreover, mTOR inactivation by rapamycin (mTOR inhibitor) increased pro-apoptotic proteins expressions and mESC apoptosis. Furthermore, transplantation of non-targeting siRNA and glucosamine-treated mESCs increased cell survival and inhibited flap necrosis in mouse skin flap model. Conversely, silencing of GPAT1 expression reversed those glucosamine effects. In conclusion, enhancing O-GlcNAcylation of Sp1 by glucosamine stimulates GPAT1 expression, which leads to inhibition of hypoxia-induced mESC apoptosis via mTOR activation.
Poly-ADP-ribosylation-mediated degradation of ARTD1 by the NLRP3 inflammasome is a prerequisite for osteoclast maturation
Authors: Wang C , Qu C , Alippe Y , Bonar S L , Civitelli R , Abu-Amer Y , Hottiger M O , Mbalaviele G
Published: March 2016

Evidence implicates ARTD1 in cell differentiation, but its role in skeletal metabolism remains unknown. Osteoclasts (OC), the bone-resorbing cells, differentiate from macrophages under the influence of macrophage colony-stimulating factor (M-CSF) and receptor-activator of NF-κB ligand (RANKL). We found that M-CSF induced ADP-ribosyltransferase diphtheria toxin-like 1 (ARTD1) auto-ADP-ribosylation in macrophages, a modification that marked ARTD1 for cleavage, and subsequently, for degradation upon RANKL exposure. We established that ARTD1 proteolysis was NLRP3 inflammasome-dependent, and occurred via the proteasome pathway. Since ARTD1 is cleaved at aspartate214, we studied the impact of ARTD1 rendered uncleavable by D214N substitution (ARTD1D214N) on skeletal homeostasis. ARTD1D214N, unlike wild-type ARTD1, was resistant to cleavage and degradation during osteoclastogenesis. As a result, ARTD1D214N altered histone modification and promoted the abundance of the repressors of osteoclastogenesis by interfering with the expression of B lymphocyte-induced maturation protein 1 (Blimp1), the master regulator of anti-osteoclastogenic transcription factors. Importantly, ARTD1D214N-expressing mice exhibited higher bone mass compared with controls, owing to decreased osteoclastogenesis while bone formation was unaffected. Thus, unless it is degraded, ARTD1 represses OC development through transcriptional regulation.
Nanoelectromechanical resonant narrow-band amplifiers
Authors: Ramezany Alireza , Mahdavi Mohammad , Pourkamali Siavash
Published: March 2016

This study demonstrates amplification of electrical signals using a very simple nanomechanical device. It is shown that vibration amplitude amplification using a combination of mechanical resonance and thermal-piezoresistive energy pumping, which was previously demonstrated to drive self-sustained mechanical oscillation, can turn the relatively weak piezoresistivity of silicon into a viable electronic amplification mechanism with power gains of >20 dB. Various functionalities ranging from frequency selection and timing to sensing and actuation have been successfully demonstrated for microscale and nanoscale electromechanical systems. Although such capabilities complement solid-state electronics, enabling state-of-the-art compact and high-performance electronics, the amplification of electronic signals is an area where micro-/nanomechanics has not experienced much progress. In contrast to semiconductor devices, the performance of the proposed nanoelectromechanical amplifier improves significantly as the dimensions are reduced to the nanoscale presenting a potential pathway toward deep-nanoscale electronics. The nanoelectromechanical amplifier can also address the need for ultranarrow-band filtering along with the amplification of low-power signals in wireless communications and certain sensing applications, which is another need that is not efficiently addressable using semiconductor technology.
Sequence features accurately predict genome-wide MeCP2 binding in vivo
Authors: Rube H. Tomas , Lee Wooje , Hejna Miroslav , Chen Huaiyang , Yasui Dag H. , Hess John F. , LaSalle Janine M. , Song Jun S. , Gong Qizhi
Published: March 2016

Methyl-CpG binding protein 2 (MeCP2) is critical for proper brain development and expressed at near-histone levels in neurons, but the mechanism of its genomic localization remains poorly understood. Using high-resolution MeCP2-binding data, we show that DNA sequence features alone can predict binding with 88% accuracy. Integrating MeCP2 binding and DNA methylation in a probabilistic graphical model, we demonstrate that previously reported genome-wide association with methylation is in part due to MeCP2’s affinity to GC-rich chromatin, a result replicated using published data. Furthermore, MeCP2 co-localizes with nucleosomes. Finally, MeCP2 binding downstream of promoters correlates with increased expression in Mecp2-deficient neurons.
CETSA screening identifies known and novel thymidylate synthase inhibitors and slow intracellular activation of 5-fluorouracil
Authors: Almqvist Helena , Axelsson Hanna , Jafari Rozbeh , Dan Chen , Mateus André , Haraldsson Martin , Larsson Andreas , Molina Daniel Martinez , Artursson Per , Lundbäck Thomas , Nordlund Pär
Published: March 2016

Target engagement is a critical factor for therapeutic efficacy. Assessment of compound binding to native target proteins in live cells is therefore highly desirable in all stages of drug discovery. We report here the first compound library screen based on biophysical measurements of intracellular target binding, exemplified by human thymidylate synthase (TS). The screen selected accurately for all the tested known drugs acting on TS. We also identified TS inhibitors with novel chemistry and marketed drugs that were not previously known to target TS, including the DNA methyltransferase inhibitor decitabine. By following the cellular uptake and enzymatic conversion of known drugs we correlated the appearance of active metabolites over time with intracellular target engagement. These data distinguished a much slower activation of 5-fluorouracil when compared with nucleoside-based drugs. The approach establishes efficient means to associate drug uptake and activation with target binding during drug discovery.
Single-cell RNA sequencing reveals molecular and functional platelet bias of aged haematopoietic stem cells
Authors: Grover Amit , Sanjuan-Pla Alejandra , Thongjuea Supat , Carrelha Joana , Giustacchini Alice , Gambardella Adriana , Macaulay Iain , Mancini Elena , Luis Tiago C. , Mead Adam , Jacobsen Sten Eirik W. , Nerlov Claus
Published: March 2016

Aged haematopoietic stem cells (HSCs) generate more myeloid cells and fewer lymphoid cells compared with young HSCs, contributing to decreased adaptive immunity in aged individuals. However, it is not known how intrinsic changes to HSCs and shifts in the balance between biased HSC subsets each contribute to the altered lineage output. Here, by analysing HSC transcriptomes and HSC function at the single-cell level, we identify increased molecular platelet priming and functional platelet bias as the predominant age-dependent change to HSCs, including a significant increase in a previously unrecognized class of HSCs that exclusively produce platelets. Depletion of HSC platelet programming through loss of the FOG-1 transcription factor is accompanied by increased lymphoid output. Therefore, increased platelet bias may contribute to the age-associated decrease in lymphopoiesis.
Jack-of-all-trades effects drive biodiversity–ecosystem multifunctionality relationships in European forests
Authors: van der Plas Fons , Manning Peter , Allan Eric , Scherer-Lorenzen Michael , Verheyen Kris , Wirth Christian , Zavala Miguel A. , Hector Andy , Ampoorter Evy , Baeten Lander , Barbaro Luc , Bauhus Jürgen , Benavides Raquel , Benneter Adam , Berthold Felix , Bonal Damien , Bouriaud Olivier , Bruelheide Helge , Bussotti Filippo , Carnol Monique , Castagneyrol Bastien , Charbonnier Yohan , Coomes David , Coppi Andrea , Bastias Cristina C. , Muhie Dawud Seid , De Wandeler Hans , Domisch Timo , Finér Leena , Gessler Arthur , Granier André , Grossiord Charlotte , Guyot Virginie , Hättenschwiler Stephan , Jactel Hervé , Jaroszewicz Bogdan , Joly François-Xavier , Jucker Tommaso , Koricheva Julia , Milligan Harriet , Müller Sandra , Muys Bart , Nguyen Diem , Pollastrini Martina , Raulund-Rasmussen Karsten , Selvi Federico , Stenlid Jan , Valladares Fernando , Vesterdal Lars , Zielínski Dawid , Fischer Markus
Published: March 2016

There is considerable evidence that biodiversity promotes multiple ecosystem functions (multifunctionality), thus ensuring the delivery of ecosystem services important for human well-being. However, the mechanisms underlying this relationship are poorly understood, especially in natural ecosystems. We develop a novel approach to partition biodiversity effects on multifunctionality into three mechanisms and apply this to European forest data. We show that throughout Europe, tree diversity is positively related with multifunctionality when moderate levels of functioning are required, but negatively when very high function levels are desired. For two well-known mechanisms, ‘complementarity’ and ‘selection’, we detect only minor effects on multifunctionality. Instead a third, so far overlooked mechanism, the ‘jack-of-all-trades’ effect, caused by the averaging of individual species effects on function, drives observed patterns. Simulations demonstrate that jack-of-all-trades effects occur whenever species effects on different functions are not perfectly correlated, meaning they may contribute to diversity–multifunctionality relationships in many of the world’s ecosystems.
Towards controlled polymer brushes via a self-assembly-assisted-grafting-to approach
Authors: Zhou Tian , Qi Hao , Han Lin , Barbash Dmitri , Li Christopher Y.
Published: March 2016

Precise synthesis of polymer brushes to modify the surface of nanoparticles and nanodevices for targeted applications has been one of the major focuses in the community for decades. Here we report a self-assembly-assisted-grafting-to approach to synthesize polymer brushes on flat substrates. In this method, polymers are pre-assembled into two-dimensional polymer single crystals (PSCs) with functional groups on the surface. Chemically coupling the PSCs onto solid substrates leads to the formation of polymer brushes. Exquisite control of the chain folding in PSCs allows us to obtain polymer brushes with well-defined grafting density, tethering points and brush conformation. Extremely high grafting density (2.12 chains per nm2) has been achieved in the synthesized single-tethered polymer brushes. Moreover, polymer loop brushes have been successfully obtained using oddly folded PSCs from telechelic chains. Our approach combines some of the important advantages of conventional ‘grafting-to’ and ‘grafting-from’ methods, and is promising for tailored synthesis of polymer brushes.
Magnetic nanoparticle film reconstruction modulated by immersion within DMSA aqueous solution
Authors: Xiang Qing , Borges Teixeira Cimei , Sun Li , Morais Paulo Cesar
Published: March 2016

The process of reconstruction of pre-fabricated films comprising maghemite nanoparticles deposited onto flat glass substrates triggered by immersion into aqueous solutions of meso-2,3-dimercaptosuccinic acid (DMSA) at increasing concentration (0.025, 0.050 and 0.100 mol/L) is herein reported. The evolution of this process was assessed by measuring the time (t) dependence of the particle analysis histogram width (W) extracted from atomic force microscopy images. Furthermore, a physical picture to model the film reconstruction which provides reconstruction time constants associated to single particles (τ1) and small agglomerates (τn), the key units associated to the process, ranging from τ1 = 2.9 and τn = 3.4 hour (0.025 mol/L) to τ1 = 5.1 and τn = 4.6 hour (0.100 mol/L) is proposed. The nanoparticle-based film reconstruction triggered by an exogenous stimulus, the use of the W versus t data to describe the process and the model picture accounting for the recorded data have not been previously reported.
Rashba Torque Driven Domain Wall Motion in Magnetic Helices
Authors: Pylypovskyi Oleksandr V. , Sheka Denis D. , Kravchuk Volodymyr P. , Yershov Kostiantyn V. , Makarov Denys , Gaididei Yuri
Published: March 2016

Manipulation of the domain wall propagation in magnetic wires is a key practical task for a number of devices including racetrack memory and magnetic logic. Recently, curvilinear effects emerged as an efficient mean to impact substantially the statics and dynamics of magnetic textures. Here, we demonstrate that the curvilinear form of the exchange interaction of a magnetic helix results in an effective anisotropy term and Dzyaloshinskii–Moriya interaction with a complete set of Lifshitz invariants for a one-dimensional system. In contrast to their planar counterparts, the geometrically induced modifications of the static magnetic texture of the domain walls in magnetic helices offer unconventional means to control the wall dynamics relying on spin-orbit Rashba torque. The chiral symmetry breaking due to the Dzyaloshinskii–Moriya interaction leads to the opposite directions of the domain wall motion in left- or right-handed helices. Furthermore, for the magnetic helices, the emergent effective anisotropy term and Dzyaloshinskii–Moriya interaction can be attributed to the clear geometrical parameters like curvature and torsion offering intuitive understanding of the complex curvilinear effects in magnetism.
Reproducibility of radiomics for deciphering tumor phenotype with imaging
Authors: Zhao Binsheng , Tan Yongqiang , Tsai Wei-Yann , Qi Jing , Xie Chuanmiao , Lu Lin , Schwartz Lawrence H.
Published: March 2016

Radiomics (radiogenomics) characterizes tumor phenotypes based on quantitative image features derived from routine radiologic imaging to improve cancer diagnosis, prognosis, prediction and response to therapy. Although radiomic features must be reproducible to qualify as biomarkers for clinical care, little is known about how routine imaging acquisition techniques/parameters affect reproducibility. To begin to fill this knowledge gap, we assessed the reproducibility of a comprehensive, commonly-used set of radiomic features using a unique, same-day repeat computed tomography data set from lung cancer patients. Each scan was reconstructed at 6 imaging settings, varying slice thicknesses (1.25 mm, 2.5 mm and 5 mm) and reconstruction algorithms (sharp, smooth). Reproducibility was assessed using the repeat scans reconstructed at identical imaging setting (6 settings in total). In separate analyses, we explored differences in radiomic features due to different imaging parameters by assessing the agreement of these radiomic features extracted from the repeat scans reconstructed at the same slice thickness but different algorithms (3 settings in total). Our data suggest that radiomic features are reproducible over a wide range of imaging settings. However, smooth and sharp reconstruction algorithms should not be used interchangeably. These findings will raise awareness of the importance of properly setting imaging acquisition parameters in radiomics/radiogenomics research.
Net-Immobilization of β-glucosidase on Nonwoven Fabrics to Lower the Cost of “Cellulosic Ethanol” and Increase Cellulose Conversions
Authors: Zhu Xing , He Bin , Zhao Changwen , Fan Rong , Zhang Lihua , Wang Guan , Ma Yuhong , Yang Wantai
Published: March 2016

The main limitation preventing the use of enzymatic cellulosic ethanol in industrial production is its higher cost which is mainly due to the elevated price of β-glucosidase (BG). Herein, we report on a simple strategy for the in-situ encapsulation of BG for repeated cellulosic ethanol production. In this strategy, BG was net-immobilized into a poly(ethylene glycol) (PEG) net-cloth layer on a PP nonwoven fabric by way of the visible light-induced surface controlled/living graft cross-linking polymerization. The visible light and mild reaction conditions could ensure the activity retention of BG during immobilization, while the non-swelling uniform net-mesh formed by living cross-linking polymerization could prevent the leakage of BG effectively (at the immobilization rate of more than 98.6% and the leakage rate of only 0.4%). When the BG-loaded fabric was used in combination with free cellulase (CEL), the results of the catalytic reaction demonstrated that these BG-loaded fabrics could not only give a 40% increase in cellulose conversions but also be reused for more than fifteen batches without losing the activity. These BG-loaded fabrics with characteristics including easy separation, excellent operation stability, a low cost of the polymeric matrix and a simple fabrication process are particularly interesting for a future bio-fuel production strategy.
Spin-Current and Spin-Splitting in Helicoidal Molecules Due to Spin-Orbit Coupling
Authors: Caetano R. A.
Published: March 2016

The use of organic materials in spintronic devices has been seriously considered after recent experimental works have shown unexpected spin-dependent electrical properties. The basis for the confection of any spintronic device is ability of selecting the appropriated spin polarization. In this direction, DNA has been pointed out as a potential candidate for spin selection due to the spin-orbit coupling originating from the electric field generated by accumulated electrical charges along the helix. Here, we demonstrate that spin-orbit coupling is the minimum ingredient necessary to promote a spatial spin separation and the generation of spin-current. We show that the up and down spin components have different velocities that give rise to a spin-current. By using a simple situation where spin-orbit coupling is present, we provide qualitative justifications to our results that clearly point to helicoidal molecules as serious candidates to integrate spintronic devices.
Hedgehog associated to microparticles inhibits adipocyte differentiation via a non-canonical pathway
Authors: Fleury Audrey , Hoch Lucile , Martinez M. Carmen , Faure Hélène , Taddei Maurizio , Petricci Elena , Manetti Fabrizio , Girard Nicolas , Mann André , Jacques Caroline , Larghero Jérôme , Ruat Martial , Andriantsitohaina Ramaroson , Le Lay Soazig
Published: March 2016

Hedgehog (Hh) is a critical regulator of adipogenesis. Extracellular vesicles are natural Hh carriers, as illustrated by activated/apoptotic lymphocytes specifically shedding microparticles (MP) bearing the morphogen (MPHh+). We show that MPHh+ inhibit adipocyte differentiation and orientate mesenchymal stem cells towards a pro-osteogenic program. Despite a Smoothened (Smo)-dependency, MPHh+ anti-adipogenic effects do not activate a canonical Hh signalling pathway in contrast to those elicited either by the Smo agonist SAG or recombinant Sonic Hedgehog. The Smo agonist GSA-10 recapitulates many of the hallmarks of MPHh+ anti-adipogenic effects. The adipogenesis blockade induced by MPHh+ and GSA-10 was abolished by the Smo antagonist LDE225. We further elucidate a Smo/Lkb1/Ampk axis as the non-canonical Hh pathway used by MPHh+ and GSA-10 to inhibit adipocyte differentiation. Our results highlight for the first time the ability of Hh-enriched MP to signal via a non-canonical pathway opening new perspectives to modulate fat development.
Quantifying the influence of Bessel beams on image quality in optical coherence tomography
Authors: Curatolo Andrea , Munro Peter R. T. , Lorenser Dirk , Sreekumar Parvathy , Singe C. Christian , Kennedy Brendan F. , Sampson David D.
Published: March 2016

Light scattered by turbid tissue is known to degrade optical coherence tomography (OCT) image contrast progressively with depth. Bessel beams have been proposed as an alternative to Gaussian beams to image deeper into turbid tissue. However, studies of turbid tissue comparing the image quality for different beam types are lacking. We present such a study, using numerically simulated beams and experimental OCT images formed by Bessel or Gaussian beams illuminating phantoms with optical properties spanning a range typical of soft tissue. We demonstrate that, for a given scattering parameter, the higher the scattering anisotropy the lower the OCT contrast, regardless of the beam type. When focusing both beams at the same depth in the sample, we show that, at focus and for equal input power and resolution, imaging with the Gaussian beam suffers less reduction of contrast. This suggests that, whilst Bessel beams offer extended depth of field in a single depth scan, for low numerical aperture (NA < 0.1) and typical soft tissue properties (scattering coefficient, μs = 3.7 mm−1 and high scattering anisotropy, g > 0.95), superior contrast (by up to ~40%) may be obtained over an extended depth range by a Gaussian beam combined with dynamic focusing.
The origin of the criticality in meme popularity distribution on complex networks
Authors: Kim Yup , Park Seokjong , Yook Soon-Hyung
Published: March 2016

Previous studies showed that the meme popularity distribution is described by a heavy-tailed distribution or a power-law, which is a characteristic feature of the criticality. Here, we study the origin of the criticality on non-growing and growing networks based on the competition induced criticality model. From the direct Mote Carlo simulations and the exact mapping into the position dependent biased random walk (PDBRW), we find that the meme popularity distribution satisfies a very robust power- law with exponent α = 3/2 if there is an innovation process. On the other hand, if there is no innovation, then we find that the meme popularity distribution is bounded and highly skewed for early transient time periods, while it satisfies a power-law with exponent α ≠ 3/2 for intermediate time periods. The exact mapping into PDBRW clearly shows that the balance between the creation of new memes by the innovation process and the extinction of old memes is the key factor for the criticality. We confirm that the balance for the criticality sustains for relatively small innovation rate. Therefore, the innovation processes with significantly influential memes should be the simple and fundamental processes which cause the critical distribution of the meme popularity in real social networks.
Coupling a DNA-Based Machine with Glucometer Readouts for Amplified Detection of Telomerase Activity in Cancer Cells
Authors: Wang Wenjing , Huang Shan , Li Jingjing , Rui Kai , Zhang Jian-Rong , Zhu Jun-Jie
Published: March 2016

The strong correlation between cancer and telomerase activity has inspired the development of new strategies to evaluate telomerase activity. Here, a personal glucose meter (PGM) system that uses DNA-based machine amplification to detect telomerase in cancer cells is reported. In this assay, telomerase elongation products are amplified in the form of another type of product by a DNA-based machine. This process can only be activated by the hybridization of the extended telomerase substrate (TS) probe and the complementary primer in the presence of telomerase. The obtained products are then transformed to glucose-related signals via a three-component assay, which enables the simple use of a PGM to indirectly quantify the telomerase activity. The proposed method realizes sensitive telomerase activity detection down to 20 HeLa cells with a significantly enhanced dynamic range. Additionally, short telomerase elongation products, such as telomerase substrate probes with two repetitive sequences, that cannot be detected using the most widely used telomeric repeat amplification protocol assay were detected.
dbPAF: an integrative database of protein phosphorylation in animals and fungi
Authors: Ullah Shahid , Lin Shaofeng , Xu Yang , Deng Wankun , Ma Lili , Zhang Ying , Liu Zexian , Xue Yu
Published: March 2016

Protein phosphorylation is one of the most important post-translational modifications (PTMs) and regulates a broad spectrum of biological processes. Recent progresses in phosphoproteomic identifications have generated a flood of phosphorylation sites, while the integration of these sites is an urgent need. In this work, we developed a curated database of dbPAF, containing known phosphorylation sites in H. sapiens, M. musculus, R. norvegicus, D. melanogaster, C. elegans, S. pombe and S. cerevisiae. From the scientific literature and public databases, we totally collected and integrated 54,148 phosphoproteins with 483,001 phosphorylation sites. Multiple options were provided for accessing the data, while original references and other annotations were also present for each phosphoprotein. Based on the new data set, we computationally detected significantly over-represented sequence motifs around phosphorylation sites, predicted potential kinases that are responsible for the modification of collected phospho-sites and evolutionarily analyzed phosphorylation conservation states across different species. Besides to be largely consistent with previous reports, our results also proposed new features of phospho-regulation. Taken together, our database can be useful for further analyses of protein phosphorylation in human and other model organisms. The dbPAF database was implemented in PHP + MySQL and freely available at http://dbpaf.biocuckoo.org.
Simulated Raman correlation spectroscopy for quantifying nucleic acid-silver composites
Authors: Freeman Lindsay M. , Smolyaninov Alexei , Pang Lin , Fainman Yeshaiahu
Published: March 2016

Plasmonic devices are of great interest due to their ability to confine light to the nanoscale level and dramatically increase the intensity of the electromagnetic field, functioning as high performance platforms for Raman signal enhancement. While Raman spectroscopy has been proposed as a tool to identify the preferential binding sites and adsorption configurations of molecules to nanoparticles, the results have been limited by the assumption that a single binding site is responsible for molecular adsorption. Here, we develop the simulated Raman correlation spectroscopy (SRCS) process to determine which binding sites of a molecule preferentially bind to a plasmonic material and in what capacity. We apply the method to the case of nucleic acids binding to silver, discovering that multiple atoms are responsible for adsorption kinetics. This method can be applied to future systems, such as to study the molecular orientation of adsorbates to films or protein conformation upon adsorption.
Structural and electronic properties of epitaxial multilayer h-BN on Ni(111) for spintronics applications
Authors: Tonkikh A. A. , Voloshina E. N. , Werner P. , Blumtritt H. , Senkovskiy B. , Güntherodt G. , Parkin S. S. P. , Dedkov Yu. S.
Published: March 2016

Hexagonal boron nitride (h-BN) is a promising material for implementation in spintronics due to a large band gap, low spin-orbit coupling, and a small lattice mismatch to graphene and to close-packed surfaces of fcc-Ni(111) and hcp-Co(0001). Epitaxial deposition of h-BN on ferromagnetic metals is aimed at small interface scattering of charge and spin carriers. We report on the controlled growth of h-BN/Ni(111) by means of molecular beam epitaxy (MBE). Structural and electronic properties of this system are investigated using cross-section transmission electron microscopy (TEM) and electron spectroscopies which confirm good agreement with the properties of bulk h-BN. The latter are also corroborated by density functional theory (DFT) calculations, revealing that the first h-BN layer at the interface to Ni is metallic. Our investigations demonstrate that MBE is a promising, versatile alternative to both the exfoliation approach and chemical vapour deposition of h-BN.
Microscopic Origin of Strain Hardening in Methane Hydrate
Authors: Jia Jihui , Liang Yunfeng , Tsuji Takeshi , Murata Sumihiko , Matsuoka Toshifumi
Published: March 2016

It has been reported for a long time that methane hydrate presents strain hardening, whereas the strength of normal ice weakens with increasing strain after an ultimate strength. However, the microscopic origin of these differences is not known. Here, we investigated the mechanical characteristics of methane hydrate and normal ice by compressive deformation test using molecular dynamics simulations. It is shown that methane hydrate exhibits strain hardening only if the hydrate is confined to a certain finite cross-sectional area that is normal to the compression direction. For normal ice, it does not present strain hardening under the same conditions. We show that hydrate guest methane molecules exhibit no long-distance diffusion when confined to a finite-size area. They appear to serve as non-deformable units that prevent hydrate structure failure and thus are responsible for the strain-hardening phenomenon.
Intense visible emission from ZnO/PAAX (X = H or Na) nanocomposite synthesized via a simple and scalable sol-gel method
Authors: Zhu Y. , Apostoluk A. , Gautier P. , Valette A. , Omar L. , Cornier T. , Bluet J. M. , Masenelli-Varlot K. , Daniele S. , Masenelli B.
Published: March 2016

Intense visible nano-emitters are key objects for many technologies such as single photon source, bio-labels or energy convertors. Chalcogenide nanocrystals have ruled this domain for several decades. However, there is a demand for cheaper and less toxic materials. In this scheme, ZnO nanoparticles have appeared as potential candidates. At the nanoscale, they exhibit crystalline defects which can generate intense visible emission. However, even though photoluminescence quantum yields as high as 60% have been reported, it still remains to get quantum yield of that order of magnitude which remains stable over a long period. In this purpose, we present hybrid ZnO/polyacrylic acid (PAAH) nanocomposites, obtained from the hydrolysis of diethylzinc in presence of PAAH, exhibiting quantum yield systematically larger than 20%. By optimizing the nature and properties of the polymeric acid, the quantum yield is increased up to 70% and remains stable over months. This enhancement is explained by a model based on the hybrid type II heterostructure formed by ZnO/PAAH. The addition of PAAX (X = H or Na) during the hydrolysis of ZnEt2 represents a cost effective method to synthesize scalable amounts of highly luminescent ZnO/PAAX nanocomposites.
Room temperature continuous wave, monolithic tunable THz sources based on highly efficient mid-infrared quantum cascade lasers
Authors: Lu Quanyong , Wu Donghai , Sengupta Saumya , Slivken Steven , Razeghi Manijeh
Published: March 2016

A compact, high power, room temperature continuous wave terahertz source emitting in a wide frequency range (ν ~ 1–5 THz) is of great importance to terahertz system development for applications in spectroscopy, communication, sensing and imaging. Here, we present a strong-coupled strain-balanced quantum cascade laser design for efficient THz generation based on intracavity difference frequency generation. Room temperature continuous wave emission at 3.41 THz with a side-mode suppression ratio of 30 dB and output power up to 14 μW is achieved with a wall-plug efficiency about one order of magnitude higher than previous demonstrations. With this highly efficient design, continuous wave, single mode THz emissions with a wide frequency tuning range of 2.06–4.35 THz and an output power up to 4.2 μW are demonstrated at room temperature from two monolithic three-section sampled grating distributed feedback-distributed Bragg reflector lasers.
Ligand-binding specificity and promiscuity of the main lignocellulolytic enzyme families as revealed by active-site architecture analysis
Authors: Tian Li , Liu Shijia , Wang Shuai , Wang Lushan
Published: March 2016

Biomass can be converted into sugars by a series of lignocellulolytic enzymes, which belong to the glycoside hydrolase (GH) families summarized in CAZy databases. Here, using a structural bioinformatics method, we analyzed the active site architecture of the main lignocellulolytic enzyme families. The aromatic amino acids Trp/Tyr and polar amino acids Glu/Asp/Asn/Gln/Arg occurred at higher frequencies in the active site architecture than in the whole enzyme structure. And the number of potential subsites was significantly different among different families. In the cellulase and xylanase families, the conserved amino acids in the active site architecture were mostly found at the −2 to +1 subsites, while in β-glucosidase they were mainly concentrated at the −1 subsite. Families with more conserved binding amino acid residues displayed strong selectivity for their ligands, while those with fewer conserved binding amino acid residues often exhibited promiscuity when recognizing ligands. Enzymes with different activities also tended to bind different hydroxyl oxygen atoms on the ligand. These results may help us to better understand the common and unique structural bases of enzyme-ligand recognition from different families and provide a theoretical basis for the functional evolution and rational design of major lignocellulolytic enzymes.