bluuebunny/crossref_metadata_2025 huggingface dataset:
The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state ab initio dynamics
Authors: Donati Greta , Petrone Alessio , Caruso Pasquale , Rega Nadia
Published: January 2018

A new time-resolved vibrational analysis unveils the mechanism of an excited state proton shuttle in green fluorescent protein.
Mechanistic insights into boron-catalysed direct amidation reactions
Authors: Arkhipenko Sergey , Sabatini Marco T. , Batsanov Andrei S. , Karaluka Valerija , Sheppard Tom D. , Rzepa Henry S. , Whiting Andrew
Published: January 2018

The generally accepted monoacyloxyboron mechanism of boron-catalysed direct amidation is brought into question in this study, and new alternatives are proposed.
Absolute and relative facial selectivities in organocatalytic asymmetric chlorocyclization reactions
Authors: Salehi Marzijarani Nastaran , Yousefi Roozbeh , Jaganathan Arvind , Ashtekar Kumar Dilip , Jackson James E. , Borhan Babak
Published: January 2018

For four related 1,1-disubstituted olefins, (DHQD)2PHAL-catalyzed asymmetric chlorocyclization delivers Cl+uniformly to one π face, but cyclizes with strong but differing netsyn vs. antiaddition.
Chain conformation of poly(acrylic acid)-graft-poly(ethylene oxide)-graft-dodecyl in solution: an anomalous counter-ions condensation
Authors: Zhou Xinlu , Zhao Kongshuang
Published: January 2018

A dielectric spectroscopy study on a polyelectrolyte in aqueous solutions, which contains hydrophobic groups in part of the side chains poly(acrylic acid)-graft-poly(ethylene oxide)-graft-dodecyl (PAA-g-PEO-g-dodecyl) is reported.
Drop impact dynamics on slippery liquid-infused porous surfaces: influence of oil thickness
Authors: Muschi M. , Brudieu B. , Teisseire J. , Sauret A.
Published: January 2018

This paper investigates the impact dynamics of a water drop on slippery liquid-infused surfaces of varying oil thickness.
Continuous splitting of aqueous droplets at the interface of co-flowing immiscible oil streams in a microchannel
Authors: Jayaprakash K. S. , Sen A. K.
Published: January 2018

We report the continuous splitting of aqueous droplets at the interface between two co-flowing immiscible oil streams in a microchannel.
Wall fluidization in two acts: from stiff to soft roughness
Authors: Derzsi Ladislav , Filippi Daniele , Lulli Matteo , Mistura Giampaolo , Bernaschi Massimo , Garstecki Piotr , Sbragaglia Mauro , Pierno Matteo
Published: January 2018

Surface induced fluidization of soft glassy materials (SGMs) in microfluidic channels may occur via two distinct scenarios, depending on the microtexture of the rough walls.
Stretch tuning of the Debye ring for 2D photonic crystals on a dielectric elastomer membrane
Authors: Yin Tenghao , Zhong Danming , Liu Junjie , Liu Xiangjiang , Yu Honghui , Qu Shaoxing
Published: January 2018

A dielectric elastomer with large deformation is used to tune the diffracted patterns of 2D photonic crystals for the first time.
Orbital controlled band gap engineering of tetragonal BiFeO3 for optoelectronic applications
Authors: Qiao L. , Zhang S. , Xiao H. Y. , Singh D. J. , Zhang K. H. L. , Liu Z. J. , Zu X. T. , Li S.
Published: January 2018

Bismuth ferrite BiFeO3 (BFO) is an important ferroelectric material for thin-film optoelectronic sensing and potential photovoltaic applications.
n-Type organic light-emitting transistors with high mobility and improved air stability
Authors: Ma Lanchao , Qin Dashan , Liu Yunqi , Zhan Xiaowei
Published: January 2018

The first example of n-type organic light-emitting transistors operated in air was demonstrated using perylene diimide as a charge-transporting and light-emitting layer.
Facile Synthesis of β-Keto Sulfones Employing Fenton’s Reagent in DMSO
Authors: Abaev Vladimir , Serdyuk Olga , Chalikidi Petrakis , Uchuskin Maxim , Trushkov Igor
Published: January 2018

A new facile method for the synthesis of β-keto sulfones employing xanthates, DMSO, and Fenton’s reagent is described. The reaction proceeds under very mild conditions providing a cost-effective straightforward approach to various β-keto sulfones in high yields.
Palladium-Catalyzed Cascade Approach to 12-(Aryl)indolo[1,2-c]quin­azolin-6(5H)-ones
Authors: Iazzetti Antonia , Marinelli Fabio , Arcadi Antonio , Cacchi Sandro , Fabrizi Giancarlo , Ghirga Francesca , Goggiamani Antonella
Published: January 2018

A straightforward one-pot approach to the synthesis of challenging 12-arylindolo[1,2-c]quinazolin-6(5H)-ones is described. Starting from readily available o-(o-aminophenylethynyl)trifluoroacetanilides, palladium-catalyzed aminoarylation of the triple bond with ArI, ArBr, and ArN2
+BF4
– is followed by cyclization of the resulting N-trifluoro­acetyl-2-(o-aminophenyl)-3-aryl indole. This sequential reaction provides the title compounds by means of a rare elimination of trifluoromethane.
A Direct Xanthate-Based Route to γ-Thiolactones
Authors: Zard Samir , Simonet-Davin Raphaël
Published: January 2018

The first examples of direct synthesis of γ-thiolactones by addition of a thiolactone-based radical are described. Mono- and bis-γ-thiolactones can be obtained by a dilauroyl peroxide initiated addition of thiolactone xanthate to various alkenes and α,ω-dienes. The process is modular and exhibits a high functional group tolerance.
Glycosyl Aldehydes: New Scaffolds for the Synthesis of Neoglycoconjugates via Bioorthogonal Oxime Bond Formation
Authors: Montenegro Javier , Reina José , Rioboo Alicia
Published: January 2018

The straightforward preparation of glycosyl neoconjugates by oxime (or hydrazone) bond formation represents a key bioorthogonal tool in chemical biology. However, when this strategy is employed by reacting the reducing end of the glycan moiety, the configuration and the stereochemical information is lost due to partial (or complete) opening of the glycan cyclic hemiacetal and the formation of the corresponding opened tautomers. We have completed the synthesis of a library of glycosyl aldehydes to be used as scaffold for the synthesis of neoglycoconjugates via oxime bond formation. These glycosyl aldehydes constitute a simple and accessible alternative to avoid loss of chiral information when conjugating, by oxime (or hydrazone) bonds, the aldehyde functionality present at the reducing end of natural carbohydrates.
Photoredox Synthesis of Arylhydroxylamines from Carboxylic Acids and Nitrosoarenes
Authors: Sheikh Nadeem , Leonori Daniele , Davies Jacob , Angelini Lucrezia , Alkhalifah Mohammed , Sanz Laia
Published: January 2018

Hydroxylamines are found in biologically active compounds and serve as building blocks for the preparation of nitrogen-containing molecules. Here the direct conversion of carboxylic acids into the corresponding alkylhydroxylamines using organo-photoredox catalysis is reported. The process relies in the generation of alkyl radicals via photoinduced oxidation-decarboxylation and their following reaction with nitrosoarenes. We have successfully applied this method to the late-stage modification of complex and biologically active acids and applied it in novel radical cascade processes.
Mechanochemical Organic Synthesis: The Art of Making Chemistry Green
Authors: Štrukil Vjekoslav
Published: January 2018

Despite growing interest in mechanochemistry, its application in the organic-synthesis laboratory has still not reached the level of being commonplace. Inspired by this apparent underrepresentation of mechanochemical practice in the broad organic-chemistry community, this article aims to highlight some of the most interesting aspects of modern mechanosynthesis, with particular emphasis on the potential of mechanochemistry to allow reaction discovery and the development of novel synthetic approaches.
The Evolving Role of MicroRNAs in Endothelial Cell Dysfunction in Response to Infection
Authors: Watkin Rebecca , Fitzpatrick Glenn , Kerrigan Steve
Published: January 2018

The microRNAs are short noncoding RNA molecules responsible for translational repression and silencing of target genes via binding to the mRNA. They are found in all eukaryotic cells and play a critical role in virtually all physiological processes, including within the cardiovascular system where they influence cellular development, differentiation, cardiovascular function, hemostasis, and programmed cell death. Dysregulated microRNA expression is associated with several conditions ranging from cancer and autoimmune disease to infection. Progressively, it has become increasingly clear that microRNAs are important components of the host response to microbes. The cardiovascular system, coupled with cells of the innate immune system, provide the initial interaction and first response to microbial infection, respectively. This review presents the current state of knowledge regarding the role of microRNAs with emphasis on their role in controlling endothelial cell function.
Metabolic Responses of Meniscus to IL-1β
Authors: Cook Alex , Cook James , Stoker Aaron
Published: January 2018

This article identifies the potential mechanisms of action for meniscal degeneration in response to joint inflammation and potential contributions of the meniscus to the development and progression of osteoarthritis (OA). It was hypothesized that interleukin-1β (IL-1β) stimulation of meniscal explants would result in significant increases in nitric oxide (NO), matrix metalloproteinase (MMP) production and activity, and relevant cytokine production compared with controls. Canine meniscal explants (4 mm) were cultured for 21 days with (IL-1) or without (negative control [NC]) 50 ng/mL rcIL-1β (n = 6/group). Media were changed every 3 days and analyzed for MMP activity, ADAMTS-4 activity, MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, NO, prostaglandin E2 (PGE2), IL-6, IL-8, monocyte chemotactic protein-1 (MCP-1), and keratinocyte-derived chemokine (KC) concentrations. Media NO and PGE2 concentrations were significantly higher in the IL-1 group at all time points except for days 9 and 12. The concentrations of MMP-13 were significantly higher in the IL-1 group at days 3, 6, 9, and 12. The production of MMP-2 was significantly lower in the IL-1 group on days 3 through 15. ADAMTS4 activity was significantly higher in the IL-1 group on days 6 through 18. MMP-3 concentrations and general MMP activity were significantly higher in the IL-1 group at all time points. Concentrations of IL-6, IL-8, MCP-1, and KC were significantly higher in the IL-1 group at most time points. Glycosaminoglycans (GAG) content decreased significantly (p = 0.009) in the IL-1 group compared with the NC group. Proinflammatory mediators appear to directly influence degradative processes in the meniscus, which in turn contribute to development and progression of OA by production of proinflammatory and degradative mediators. These findings have important clinical implications for the management of the degenerative meniscus and the osteoarthritic knee.
Zum 58. Jahreskongress der Deutschen Gesellschaft für Handchirurgie (DGH) in München
Authors: Giunta Riccardo
Published: December 2017

Im Oktober fand der 58. Kongresses der Deutschen Gesellschaft für Handchirurgie (DGH) vom 11. bis 14. Oktober 2017 gemeinsam mit dem 22. Kongress
der Deutschsprachigen Arbeitsgemeinschaft für Handtherapie (DAHTH) bei uns im Münchner Gasteig statt. Als Tagungspräsidenten hatte ich von der
DGH die Gelegenheit bekommen, die Jahrestagung wissenschaftlich und organisatorisch auszugestalten. Unser Ziel als akademische Handchirurgie an
der Ludwig-Maximilians-Universität (LMU) München war es eine Tagung zu organisieren, die einerseits die Handchirurgie mit allen ihren
verschiedenen Teilaspekten wissenschaftlich unter dem Motto „Handchirurgie inspiriert“ darstellt und andererseits das Tagungsformat
weiterzuentwickeln sowie die Tagung im Hinblick auf den Weltkongress der IFSSH in Berlin 2019 vor allem auch international zu öffnen.
High current density and low emission field of carbon nanotube array microbundle
Authors: Zhang Quan , Wang Xi-juan , Meng Peng , Yue Hong-xin , Zheng Rui-ting , Wu Xiao-ling , Cheng Guo-an
Published: January 2018

Field electron emission from carbon nanotubes shows promising application potential in devices. Low adhesive bonding strength between the carbon nanotubes and the substrate presents a practical challenge in environments such as high field emission current density. In this paper, we report on the performance of a carbon nanotube microbundle attached to a tungsten needle by a uniform glue layer. The device is easily fabricated without complex fixture and possesses a complete array structure. After curing the glue in air, the adhesive strength between the carbon nanotubes and the needle is over 2000 N/cm2. Field emission measurements demonstrate that the maximum current density of the emitters is over 20 A/cm2 under a low applied field (<0.4 V/μm). The emitter with high current density, low emission field, and good stability has a wide range of applications in flat displays, X-ray tubes, and lamps.
A reducible Weil representation of sp(4) realized by differential operators in the space of smooth functions on H2 × S1
Authors: Afra M. , Fakhri H. , Sayyah-Fard M.
Published: January 2018

This work presents a novel way to obtain the associated Romanovski functions Rn,m(x) with n ≥ m in the three separate regions in terms of n and m. We obtain the raising and lowering relations with respect to the both indices, simultaneously, in the three regions. Then, a reducible Weil representation of the real Lie algebra sp(4) is realized in the space of complex-valued smooth functions on H2 × S1 by differential forms for the Cartan-Weyl basis. Its invariant subspace is the second rare instance of the highest weight irreducible representation of sp(4) all whose weight spaces are one-dimensional.
Biomimetic microfluidic platform for the quantification of transient endothelial monolayer permeability and therapeutic transport under mimicked cancerous conditions
Authors: Uhl Christopher George , Muzykantov Vladimir R. , Liu Yaling
Published: January 2018

Therapeutic delivery from microvasculature to cancerous sites is influenced by many factors including endothelial permeability, vascular flow rates/pressures, cancer secretion of cytokines and permeabilizing agents, and characteristics of the chosen therapeutics. This work uses bi-layer microfluidics capable of studying dye and therapeutic transport from a simulated vessel to a cancerous region while allowing for direct visualization and quantification of endothelial permeability. 2.5 to 13 times greater dye transport was observed when utilizing small dye sizes (FITC) when compared to larger molecules (FITC-Dextran 4 kDa and FITC-Dextran 70 kDa), respectively. The use of lower flow rates/pressures is shown to improve dye transport by factors ranging from 2.5 to 5 times, which result from increased dye diffusion times within the system. Furthermore, subjecting confluent endothelial monolayers to cancerous cells resulted in increased levels of vascular permeability. Situations of cancer induced increases in vascular permeability are shown to facilitate enhanced dye transport when compared to non-diseased endothelial monolayers. Subsequent introduction of paclitaxel or doxorubicin into the system was shown to kill cancerous cells resulting in the recovery of endothelial confluency overtime. The response of endothelial cells to paclitaxel and doxorubicin is quantified to understand the direct influence of anti-cancer therapeutics on endothelial growth and permeability. Introduction of therapeutics into the system showed the recovery of endothelial confluency and dye transport back to conditions experienced prior to cancer cell introduction after 120 h of continuous treatment. Overall, the system has been utilized to show that therapeutic transport to cancerous sites depends on the size of the chosen therapeutic, the flow rate/pressure established within the vasculature, and the degree of cancer induced endothelial permeability. In addition, treatment of the cancerous region has been demonstrated with anti-cancer therapeutics, which are shown to influence vascular permeability in direct (therapeutics themselves) and indirect (death of cancer cells) manners. Lastly, the system presented in this work is believed to function as a versatile testing platform for future anti-cancer therapeutic testing and development.
Tuning transport performance in two-dimensional metal-organic framework semiconductors: Role of the metal d band
Authors: Tang Liang-Po , Tang Li-Ming , Geng Hua , Yi Yuan-Ping , Wei Zhongming , Chen Ke-Qiu , Deng Hui-Xiong
Published: January 2018

Hybrid metal-organic frameworks have some exotic electronic properties, such as extremely high electron and hole mobilities and nontrivial topological properties. Here, we systematically study the electronic properties of the two-dimensional metal-organic framework semiconductors (MOFSs) (M3S6C6, M = Mg, Ca, Zn, Cd, Ge, and Sn) using the first principles calculations. We find that the metal d band is important in determining the hole transport properties of M3S6C6. The p-d hybridization between the metal d and S-C p bands will delocalize the wavefunction of the band edge states and reduce the effective mass. From group IIA (Mg, Ca) to IVA (Ge, Sn) to IIB (Zn, Cd), as the p-d coupling increases, the hole effective masses dramatically decrease. Additionally, due to the fact that the conduction band minimum of group IIB (Zn, Cd) MOFSs is mainly dominated by the delocalized M s state, they also have the very small electron effective mass. Therefore, the 2D group IIB (Zn, Cd) MOFSs have excellent hole and electron effective masses, which are comparable with the conventional semiconductors and even better than the popular 2D materials WS2 and MoS2. This result suggests that Zn3S6C6 and Cd3S6C6 MOFSs could be the promising 2D semiconductors for the electronic applications.
Crystal structural evolution and hybrid improper ferroelectricity in Ruddlesden-Popper Ca3-xSrxTi2O7 ceramics
Authors: Li G. J. , Liu X. Q. , Lu J. J. , Zhu H. Y. , Chen X. M.
Published: January 2018

Hybrid improper ferroelectricity (HIF) has been proposed as a candidate approach to create room-temperature multiferroic materials with an intrinsic electric-field controlled magnetism effect, and HIFs in bi-layered Ruddlesden-Popper Ca3-xSrxTi2O7 ceramics have been confirmed in the present work. The ferroelectric hysteresis loops are observed in these ceramics at room temperature, and the polar orthorhombic structures with oxygen octahedral rotation and tilt modes have been confirmed by room-temperature X-ray powder diffraction. The amplitudes of oxygen octahedral rotation and tilt modes decrease with the increasing x value, which in turn leads to the decrease of remnant polarization in these ceramics. A first-order phase transition has been evidenced by the differential scanning calorimetry measurement, and the temperature of phase transition decreases linearly with the increasing content of strontium cations. It is found that the amplitude of oxygen octahedral distortion is the dominating factor that affects ferroelectric polarization in partial-ordered bi-layered Ca3Ti2O7-based ceramics.
Edge enhanced growth induced shape transition in the formation of GaN nanowall network
Authors: Nayak Sanjay , Kumar Rajendra , Shivaprasad S. M.
Published: January 2018

We address the mechanism of early stages of growth and shape transition of the unique nanowall network (NwN) of GaN by experimentally monitoring its morphological evolution and complementing it by first-principles calculations. Using atomic force and scanning electron microscopy, we observe the formation of oval shaped islands at very early stages of the growth which later transformed into tetrahedron shaped (3 faced pyramid) islands. These tetrahedron shaped islands further grow anisotropically along their edges of the (202¯1) facets to form the wall-like structure as the growth proceeds. The mechanism of this crystal growth is discussed in light of surface free energies of the different surfaces, adsorption energy, and diffusion barrier of Ga ad-atoms on the (202¯1) facets. By first-principles calculations, we find that the diffusion barrier of ad-atoms reduces with decreasing width of facets and is responsible for the anisotropic growth leading to the formation of NwN. This study suggests that formation of NwN is an archetype example of structure dependent attachment kinetic instability induced shape transition in thin film growth.
Characterizing highly dynamic conformational states: The transcription bubble in RNAP-promoter open complex as an example
Authors: Lerner Eitan , Ingargiola Antonino , Weiss Shimon
Published: January 2018

Bio-macromolecules carry out complicated functions through structural changes. To understand their mechanism of action, the structure of each step has to be characterized. While classical structural biology techniques allow the characterization of a few “structural snapshots” along the enzymatic cycle (usually of stable conformations), they do not cover all (and often fast interconverting) structures in the ensemble, where each may play an important functional role. Recently, several groups have demonstrated that structures of different conformations in solution could be solved by measuring multiple distances between different pairs of residues using single-molecule Förster resonance energy transfer (smFRET) and using them as constrains for hybrid/integrative structural modeling. However, this approach is limited in cases where the conformational dynamics is faster than the technique’s temporal resolution. In this study, we combine existing tools that elucidate sub-millisecond conformational dynamics together with hybrid/integrative structural modeling to study the conformational states of the transcription bubble in the bacterial RNA polymerase-promoter open complex (RPo). We measured microsecond alternating laser excitation-smFRET of differently labeled lacCONS promoter dsDNA constructs. We used a combination of burst variance analysis, photon-by-photon hidden Markov modeling, and the FRET-restrained positioning and screening approach to identify two conformational states for RPo. The experimentally derived distances of one conformational state match the known crystal structure of bacterial RPo. The experimentally derived distances of the other conformational state have characteristics of a scrunched RPo. These findings support the hypothesis that sub-millisecond dynamics in the transcription bubble are responsible for transcription start site selection.
Surface acoustic wave electric field effect on acoustic streaming: Numerical analysis
Authors: Darinskii A. N. , Weihnacht M. , Schmidt H.
Published: January 2018

The paper numerically studies the contribution of the electric field accompanying the surface acoustic wave to the actuation of the acoustic streaming in microchannels. The finite element method is used. The results obtained as applied to the surface waves on 128° and 64°-rotated Y cuts of LiNbO3 demonstrate that the force created by the electric field is capable of accelerating appreciably the acoustic streaming. In particular, examples are given for the situations where the electric field increases the streaming velocity by a factor of about 2–3 and significantly changes the flow pattern as compared to predictions of computations ignoring the electric field.
Quantum mechanics/coarse-grained molecular mechanics (QM/CG-MM)
Authors: Sinitskiy Anton V. , Voth Gregory A.
Published: January 2018

Numerous molecular systems, including solutions, proteins, and composite materials, can be modeled using mixed-resolution representations, of which the quantum mechanics/molecular mechanics (QM/MM) approach has become the most widely used. However, the QM/MM approach often faces a number of challenges, including the high cost of repetitive QM computations, the slow sampling even for the MM part in those cases where a system under investigation has a complex dynamics, and a difficulty in providing a simple, qualitative interpretation of numerical results in terms of the influence of the molecular environment upon the active QM region. In this paper, we address these issues by combining QM/MM modeling with the methodology of “bottom-up” coarse-graining (CG) to provide the theoretical basis for a systematic quantum-mechanical/coarse-grained molecular mechanics (QM/CG-MM) mixed resolution approach. A derivation of the method is presented based on a combination of statistical mechanics and quantum mechanics, leading to an equation for the effective Hamiltonian of the QM part, a central concept in the QM/CG-MM theory. A detailed analysis of different contributions to the effective Hamiltonian from electrostatic, induction, dispersion, and exchange interactions between the QM part and the surroundings is provided, serving as a foundation for a potential hierarchy of QM/CG-MM methods varying in their accuracy and computational cost. A relationship of the QM/CG-MM methodology to other mixed resolution approaches is also discussed.
Multivariate analysis and extraction of parameters in resistive RAMs using the Quantum Point Contact model
Authors: Roldán J. B. , Miranda E. , González-Cordero G. , García-Fernández P. , Romero-Zaliz R. , González-Rodelas P. , Aguilera A. M. , González M. B. , Jiménez-Molinos F.
Published: January 2018

A multivariate analysis of the parameters that characterize the reset process in Resistive Random Access Memory (RRAM) has been performed. The different correlations obtained can help to shed light on the current components that contribute in the Low Resistance State (LRS) of the technology considered. In addition, a screening method for the Quantum Point Contact (QPC) current component is presented. For this purpose, the second derivative of the current has been obtained using a novel numerical method which allows determining the QPC model parameters. Once the procedure is completed, a whole Resistive Switching (RS) series of thousands of curves is studied by means of a genetic algorithm. The extracted QPC parameter distributions are characterized in depth to get information about the filamentary pathways associated with LRS in the low voltage conduction regime.
Evaluation of magnetic field’s uniformity inside electromagnetic coils using graphene
Authors: Amanatiadis Stamatios A. , Kantartzis Nikolaos V. , Ohtani Tadao , Kanai Yasushii
Published: January 2018

The distribution of the magnetic field in electromagnetic coils, such as those employed in magnetic resonance imaging (MRI), is evaluated in this paper, through graphene gyrotropic properties. Initially, the rotation of an incident linearly polarized plane wave, due to an infinite graphene layer, is studied theoretically via the extraction of the perpendicular, to the polarization, electric component of the transmitted wave. Moreover, the influence of the magnetic bias field strength on this component is, also, examined, indicating the eligibility of graphene to detect magnetostatic field variations. To this aim, a specific device is proposed, consisting of a high frequency source, an electric field detector, and a finite graphene sheet that differs from the infinite one of the analytical case. To quantify the distance that the gyrotropic effects are detectable, the effective region is introduced and extracted via a properly modified finite-difference time-domain (FDTD) algorithm. The featured device is verified through a setup comprising a uniform electromagnetic coil, where the generated magnetostatic field is calculated at several cross-sections of the coil and compared to actual field values. Results indicate the accuracy and sensitivity of the designed device for the unambiguous regions.
SNR improvement by variation of recording and media parameters for a HAMR exchange coupled composite media
Authors: Natekar N. A. , Liu Zengyuan , Hernandez Stephanie , Victora R. H.
Published: January 2018

An exchange coupled composite media structure proposed previously seems to address both the issue of Tc variation in FePt as well as poor SNR/User Density during the HAMR process. Here we examine a thinner 3-6 nm structure that is likely easier to fabricate than the previous 13.5 nm thick structure. We find that increasing the damping within the write (superparamagnetic) layer and introducing intergranular exchange within the grains in the write layer are both successful approaches to improve the recorded SNR. Ensemble waveform analysis that allows the breakdown of the total SNR into transition SNR (due to AC noise) and remanence SNR (due to DC noise) helps identify the leading causes for this SNR improvement. Further studies indicate that varying the peak heat spot temperature in the HAMR write process is also a successful approach for improving the recorded SNR. This lends credence to the idea that a thinner composite media may still be used successfully to realize significant enhancements of SNR and the corresponding user density.
Control of vortex state in cobalt nanorings with domain wall pinning centers
Authors: Lal Manohar , Sakshath S. , Mohanan Parakkat Vineeth , Anil Kumar P. S.
Published: January 2018

Magnetic rings at the mesoscopic scale exhibit new spin configuration states and switching behavior, which can be controlled via geometrical structure, material composition and applied field. Vortex states in magnetic nanorings ensure flux closure, which is necessary for low stray fields in high packing density in memory devices. We performed magnetoresistance measurements on cobalt nanoring devices and show that by attaching nanowires to the ring, the vortex state can be stabilized. When a square pad is attached to the free end of the wire, the domain wall nucleation field in the nanowire is reduced. In addition, the vortex state persists over a larger range of magnetic fields, and exists at all in-plane orientations of the magnetic field. These experimental findings are well supported by our micromagnetic simulations.
Roles of coercivity and remanent flux density of permanent magnet in interior permanent magnet synchronous motor (IPMSM) performance for electric vehicle applications
Authors: Won Hoyun , Hong Yang-Ki , Lee Woncheol , Choi Minyeong
Published: January 2018

We used four rotor topologies of an interior permanent magnet synchronous motor (IPMSM) to investigate the effects of remanent flux density (Br) and coercivity (Hc) of permanent magnet on motor performance. Commercial strontium hexaferrite (SrFe12O19: energy product, (BH)max, of 4.62 MGOe) and Nd-Fe-B ((BH)max of 38.2 MGOe) magnets were used for the rotor designs. The same machine specifications and magnet volume keep constant, while the Hc and Br vary to calculate torque and energy efficiency with the finite-element analysis. A combination of high Hc and low Br more effectively increased maximum torque of IPMSM when the hexaferrite magnet was used. For Nd-Fe-B magnet, the same combination did not affect maximum torque, but increased energy efficiency at high speed. Therefore, the Hc value of a permanent magnet is more effective than the Br in producing high maximum torque for SrM-magnet based IPMSM and high energy efficiency at high speed for Nd-Fe-B magnet based IPMSM.
234 nm and 246 nm AlN-Delta-GaN quantum well deep ultraviolet light-emitting diodes
Authors: Liu Cheng , Ooi Yu Kee , Islam S. M. , Xing Huili (Grace) , Jena Debdeep , Zhang Jing
Published: January 2018

Deep ultraviolet (DUV) AlN-delta-GaN quantum well (QW) light-emitting diodes (LEDs) with emission wavelengths of 234 nm and 246 nm are proposed and demonstrated in this work. Our results reveal that the use of AlN-delta-GaN QW with ∼1–3 monolayer GaN delta-layer can achieve a large transverse electric (TE)-polarized spontaneous emission rate instead of transverse magnetic-polarized emission, contrary to what is observed in conventional AlGaN QW in the 230–250 nm wavelength regime. The switching of light polarization in the proposed AlN-delta-GaN QW active region is attributed to the rearrangement of the valence subbands near the Γ-point. The light radiation patterns obtained from angle-dependent electroluminescence measurements for the Molecular Beam Epitaxy (MBE)-grown 234 nm and 246 nm AlN-delta-GaN QW LEDs show that the photons are mainly emitted towards the surface rather than the edge, consistent with the simulated patterns achieved by the finite-difference time-domain modeling. The results demonstrate that the proposed AlN-delta-GaN QWs would potentially lead to high-efficiency TE-polarized surface-emitting DUV LEDs.
Methane dissociation on the steps and terraces of Pt(211) resolved by quantum state and impact site
Authors: Chadwick Helen , Guo Han , Gutiérrez-González Ana , Menzel Jan Paul , Jackson Bret , Beck Rainer D.
Published: January 2018

Methane dissociation on the step and terrace sites of a Pt(211) single crystal was studied by reflection absorption infrared spectroscopy (RAIRS) at a surface temperature of 120 K. The C—H stretch RAIRS signal of the chemisorbed methyl product species was used to distinguish between adsorption on step and terrace sites allowing methyl uptake to be monitored as a function of incident kinetic energy for both sites. Our results indicate a direct dissociation mechanism on both sites with higher reactivity on steps than on terraces consistent with a difference in an activation barrier height of at least 30 kJ/mol. State-specific preparation of incident CH4 with one quantum of antisymmetric (ν3) stretch vibration further increases the CH4 reactivity enabling comparison between translational and vibrational activation on both steps and terraces. The reaction is modeled with first principles quantum theory that accurately describes dissociative chemisorption at different sites on the surface.
Electronic structure of indium-tungsten-oxide alloys and their energy band alignment at the heterojunction to crystalline silicon
Authors: Menzel Dorothee , Mews Mathias , Rech Bernd , Korte Lars
Published: January 2018

The electronic structure of thermally co-evaporated indium-tungsten-oxide films is investigated. The stoichiometry is varied from pure tungsten oxide to pure indium oxide, and the band alignment at the indium-tungsten-oxide/crystalline silicon heterointerface is monitored. Using in-system photoelectron spectroscopy, optical spectroscopy, and surface photovoltage measurements, we show that the work function of indium-tungsten-oxide continuously decreases from 6.3 eV for tungsten oxide to 4.3 eV for indium oxide, with a concomitant decrease in the band bending at the hetero interface to crystalline silicon than indium oxide.
Investigation of local modification and luminescence of a carbon nanotube by scanning tunneling microscopy
Authors: Katano Satoshi , Fujita Hiroto , Uehara Yoichi
Published: January 2018

We have studied the nanoscale luminescence from a multiwalled carbon nanotube (CNT) adsorbed on Au(111) using a scanning tunneling microscope (STM). STM images revealed that a number of isolated chains of CNTs can be deposited by dry contact transfer while keeping the surface clean. By injecting tunneling electrons from the STM tip to the CNT, we observed STM light emission (STM-LE) from the CNT in the visible-light range, showing electronic transitions between the bands associated with the van Hove singularity in the density of states of the CNT. The STM-LE spectrum was obviously changed after introducing the local defect created by the STM tip, indicating the controllability of the nanoscale luminescence within a single chain of a CNT.
Perspective: Maximum caliber is a general variational principle for dynamical systems
Authors: Dixit Purushottam D. , Wagoner Jason , Weistuch Corey , Pressé Steve , Ghosh Kingshuk , Dill Ken A.
Published: January 2018

We review here Maximum Caliber (Max Cal), a general variational principle for inferring distributions of paths in dynamical processes and networks. Max Cal is to dynamical trajectories what the principle of maximum entropy is to equilibrium states or stationary populations. In Max Cal, you maximize a path entropy over all possible pathways, subject to dynamical constraints, in order to predict relative path weights. Many well-known relationships of non-equilibrium statistical physics—such as the Green-Kubo fluctuation-dissipation relations, Onsager’s reciprocal relations, and Prigogine’s minimum entropy production—are limited to near-equilibrium processes. Max Cal is more general. While it can readily derive these results under those limits, Max Cal is also applicable far from equilibrium. We give examples of Max Cal as a method of inference about trajectory distributions from limited data, finding reaction coordinates in bio-molecular simulations, and modeling the complex dynamics of non-thermal systems such as gene regulatory networks or the collective firing of neurons. We also survey its basis in principle and some limitations.
Graphene assisted effective hole-extraction on In2O3:H/CH3NH3PbI3 interface: Studied by modulated surface spectroscopy
Authors: Vinoth Kumar Sri Hari Bharath , Muydinov Ruslan , Kol'tsova Tat‘yana , Erfurt Darja , Steigert Alexander , Tolochko Oleg , Szyszka Bernd
Published: January 2018

Charge separation in CH3NH3PbI3 (MAPbI3) films deposited on a hydrogen doped indium oxide (In2O3:H) photoelectrode was investigated by modulated surface photovoltage (SPV) spectroscopy in a fixed capacitor arrangement. It was found that In2O3:H reproducibly extracts photogenerated-holes from MAPbI3 films. The oxygen-plasma treatment of the In2O3:H surface is suggested to be a reason for this phenomenon. Introducing graphene interlayer increased charge separation nearly 6 times as compared to that on the In2O3:H/MAPbI3 interface. Furthermore, it is confirmed by SPV spectroscopy that the defects of the MAPbI3 interface are passivated by graphene.
Theory of ion-matrix-sheath dynamics
Authors: Kos L. , Tskhakaya D. D.
Published: January 2018

The time evolution of a one-dimensional, uni-polar ion sheath (an “ion matrix sheath”) is investigated. The analytical solutions for the ion-fluid and Poisson’s equations are found for an arbitrary time dependence of the wall-applied negative potential. In the case that the wall potential is large and remains constant after its ramp-up application, the explicit time dependencies of the sheath’s parameters during the initial stage of the process are given. The characteristic rate of approaching the stationary state, satisfying the Child–Langmuir law, is determined.
High Z neoclassical transport: Application and limitation of analytical formulae for modelling JET experimental parameters
Authors: Breton S. , Casson F. J. , Bourdelle C. , Angioni C. , Belli E. , Camenen Y. , Citrin J. , Garbet X. , Sarazin Y. , Sertoli M. ,   JET Contributors
Published: January 2018

Heavy impurities, such as tungsten (W), can exhibit strongly poloidally asymmetric density profiles in rotating or radio frequency heated plasmas. In the metallic environment of JET, the poloidal asymmetry of tungsten enhances its neoclassical transport up to an order of magnitude, so that neoclassical convection dominates over turbulent transport in the core. Accounting for asymmetries in neoclassical transport is hence necessary in the integrated modeling framework. The neoclassical drift kinetic code, NEO [E. Belli and J. Candy, Plasma Phys. Controlled Fusion P50, 095010 (2008)], includes the impact of poloidal asymmetries on W transport. However, the computational cost required to run NEO slows down significantly integrated modeling. A previous analytical formulation to describe heavy impurity neoclassical transport in the presence of poloidal asymmetries in specific collisional regimes [C. Angioni and P. Helander, Plasma Phys. Controlled Fusion 56, 124001 (2014)] is compared in this work to numerical results from NEO. Within the domain of validity of the formula, the factor for reducing the temperature screening due to poloidal asymmetries had to be empirically adjusted. After adjustment, the modified formula can reproduce NEO results outside of its definition domain, with some limitations: When main ions are in the banana regime, the formula reproduces NEO results whatever the collisionality regime of impurities, provided that the poloidal asymmetry is not too large. However, for very strong poloidal asymmetries, agreement requires impurities in the Pfirsch-Schlüter regime. Within the JETTO integrated transport code, the analytical formula combined with the poloidally symmetric neoclassical code NCLASS [W. A. Houlberg et al., Phys. Plasmas 4, 3230 (1997)] predicts the same tungsten profile as NEO in certain cases, while saving a factor of one thousand in computer time, which can be useful in scoping studies. The parametric dependencies of the temperature screening reduction due to poloidal asymmetries would need to be better characterised for this faster model to be extended to a more general applicability.
Aggressive prostate cancer cell nuclei have reduced stiffness
Authors: Khan Zeina S. , Santos Julianna M. , Hussain Fazle
Published: January 2018

It has been hypothesized that highly metastatic cancer cells have softer nuclei and hence would travel faster through confining environments. Our goal was to prove this untested hypothesis for prostate cells. Our nuclear creep experiments using a microfluidic channel with a narrow constriction show that stiffness of aggressive immortalized prostate cancer nuclei is significantly lower than that of immortalized normal cell nuclei and hence can be a convenient malignancy marker. Nuclear stiffness is found to be the highest for cells expressing high levels of lamin A/C but lowest for cells expressing low lamin A/C levels. Decreased chromatin condensation found in softer nuclei suggests that the former can also be a marker for aggressive cancers.
Ocean-atmosphere coupling in supermodel exploits opposing wind effects
Authors: Majors J. H.
Published: January 2018

Supermodeling of the Tropical Pacific climate reproduces observed dynamical balances between ocean and atmosphere by combining wind responses of two different atmosphere models coupled to the same ocean state.
New technique reduces miRNA detection time from a day to a lunch break
Authors: Patrick Chris
Published: January 2018

Researchers integrate ICP-based microfluidic concentrator with a morpholino microarray to increase speed of miRNA detection by 48 times.
Preservation of the genetic diversity of a local common carp in the agricultural heritage rice–fish system
Authors: Ren Weizheng , Hu Liangliang , Guo Liang , Zhang Jian , Tang Lu , Zhang Entao , Zhang Jiaen , Luo Shiming , Tang Jianjun , Chen Xin
Published: January 2018

Significance

This paper contributes to understanding how traditional agriculture can maintain large genetic diversity. We quantify the effects of traditional farmer activities on the genetic diversity of an indigenous common carp in the 1,200-y-old agriculture heritage rice−fish system. We show that small farmer households interdependently incubating fish fry for their rice−fish farming shape the genetic pattern and help to maintain high genetic diversity of this local common carp. We also show how the traditional practice of mixed culturing of diverse color types potentially promotes genetic diversity. We suggest that the locally adapted ways of traditional farmers obtaining and using local genetic resources for their farming play an important role in the biodiversity of farmed crops and animals. It can become a “hotspot” for genetic diversity conservation in agriculture.
Lymphocytes eject interferogenic mitochondrial DNA webs in response to CpG and non-CpG oligodeoxynucleotides of class C
Authors: Ingelsson Björn , Söderberg Daniel , Strid Tobias , Söderberg Anita , Bergh Ann-Charlotte , Loitto Vesa , Lotfi Kourosh , Segelmark Mårten , Spyrou Giannis , Rosén Anders
Published: January 2018

Significance

Release of pathogen- and danger-associated molecular patterns (PAMPs and DAMPs) contributes to inflammatory responses and antiviral signaling. Mitochondrial DNA (mtDNA) is a potent DAMP molecule observed in blood circulation of trauma, autoimmune, HIV, and certain cancer patients. Here, we report a previously unrecognized lymphocyte feature that CpG and non-CpG oligodeoxynucleotides of class C promptly induce release of mtDNA as extracellular web-like structures. Lymphocyte mtDNA webs provoked antiviral type I IFN production in peripheral blood mononuclear cells but were devoid of bactericidal proteins. Notably, cells remained viable after the release. Our findings imply an alternative role for lymphocytes in antiviral signaling by utilizing their mtDNA as a rapid signaling molecule to communicate danger.
Graphene-based bimorphs for micron-sized, autonomous origami machines
Authors: Miskin Marc Z. , Dorsey Kyle J. , Bircan Baris , Han Yimo , Muller David A. , McEuen Paul L. , Cohen Itai
Published: January 2018

Significance

We build origami machines the size of cells by folding them out of atomically thin paper. At the heart of our approach is an actuator technology made from graphene and a nanometer-thick layer of glass. We use these actuators to fold 2D patterns into targeted 3D structures. The resulting machines are freely deployed in solutions, can change shape in fractions of a second, carry loads large enough to support embedded electronics, and can be fabricated en masse. This work opens the door to a generation of small machines for sensing, robotics, energy harvesting, and interacting with biological systems on the cellular level.
High fire-derived nitrogen deposition on central African forests
Authors: Bauters Marijn , Drake Travis W. , Verbeeck Hans , Bodé Samuel , Hervé-Fernández Pedro , Zito Phoebe , Podgorski David C. , Boyemba Faustin , Makelele Isaac , Cizungu Ntaboba Landry , Spencer Robert G. M. , Boeckx Pascal
Published: January 2018

Significance

Atmospheric N deposition affects productivity and biodiversity of forests worldwide. However, field-based estimates of atmospheric N deposition for tropical forests are extremely sparse. Our results from a monitoring network in the central Congo Basin exceed current regional N deposition simulations. Ultrahigh-resolution mass spectrometry and modeling techniques reveal that savannah biomass burning is the main source for this elevated atmospheric N deposition. Furthermore, a large fraction is deposited as organic N, which is typically not simulated or measured in monitoring networks. These high levels of N deposition have clear ramifications for the ecology and biogeochemistry of the Congo Basin.
Gene regulation and suppression of type I interferon signaling by STAT3 in diffuse large B cell lymphoma
Authors: Lu Li , Zhu Fen , Zhang Meili , Li Yangguang , Drennan Amanda C. , Kimpara Shuichi , Rumball Ian , Selzer Christopher , Cameron Hunter , Kellicut Ashley , Kelm Amanda , Wang Fangyu , Waldmann Thomas A. , Rui Lixin
Published: January 2018

Significance

We demonstrate that STAT3 is a critical transcriptional regulator of the activated B cell–like subtype of diffuse large B cell lymphoma (ABC DLBCL), the most common, aggressive, non-Hodgkin lymphoma. By genome-wide assessment, we have identified target genes of STAT3. Gene regulation by STAT3 in ABC DLBCL accentuates survival signaling pathways while dampening the lethal type I interferon pathway. Knowledge of these STAT3-regulated genes has led to our demonstration that a small-molecule inhibitor in the JAK1-STAT3 signaling pathway synergizes with the type I interferon inducer lenalidomide, suggesting a new therapeutic strategy for ABC DLBCL, a subtype that is particularly difficult to treat and has poor prognosis.