bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural effects of trifluoromethylation and fluorination in gold(i) BIPHEP fluorothiolates
Authors: Moreno-Alcántar Guillermo , Manuel Guevara-Vela José , Delgadillo-Ruíz Rafael , Rocha-Rinza Tomás , Martín Pendás Ángel , Flores-Álamo Marcos , Torrens Hugo
Published: September 2017

Ligand effects on the non-covalent interactions of phosphine gold(i) fluorothiolates were analysed using the QTAIM and NCI.
Facile oxidative cyclization to access C2-quaternary 2-hydroxy-indolin-3-ones: synthetic studies towards matemone
Authors: Wen Sai-Shuai , Zhou Zhao-Fang , Xiao Jun-An , Li Jun , Xiang Haoyue , Yang Hua
Published: September 2017

Synergistic oxidation can do it! The precursor for matemone can be facilely prepared in 21% overall yield in 8 steps. The key step is the oxidative cyclization by utilizing CAN and TEMPO to install the quaternary centre.
A rhodamine based turn-on chemosensor for Fe3+ in aqueous medium and interactions of its Fe3+ complex with HSA
Authors: Bhowmick Rahul , Islam Abu Saleh Musha , Giri Arindam , Katarkar Atul , Ali Mahammad
Published: September 2017

A novel hexa-coordinating rhodamine-based chemosensor, HL6, selectively and rapidly recognizes Fe3+ in the presence of a number of metal cations, numerous anions and amino acids in purely aqueous medium with live cell imaging applications.
Discussion about the use of the volume specific surface area (VSSA) as a criterion to identify nanomaterials according to the EU definition. Part two: experimental approach
Authors: Lecloux André J. , Atluri Rambabu , Kolen'ko Yury V. , Deepak Francis Leonard
Published: September 2017

The applicability of the volume specific surface area (VSSA) concept to identify nanomaterials according to the European Commission Recommendation is demonstrated on the basis of an experimental study.
Influence of surface coating on the intracellular behaviour of gold nanoparticles: a fluorescence correlation spectroscopy study
Authors: Silvestri A. , Di Silvio D. , Llarena I. , Murray R. A. , Marelli M. , Lay L. , Polito L. , Moya S. E.
Published: September 2017

Fluorescence correlation spectroscopy allows the correlation of the state of aggregation in vitro with the intracellular fate of gold NPs for different antifouling coatings.
An aryl-triazole foldamer containing a 1,8-naphthalimide fluorescent motif for monitoring and enhancing the anion-induced folding
Authors: Yang Ling , Wang Ying , Che Yanke , Jiang Hua
Published: September 2017

A 1,8-naphthalimide fluorescent motif was found to facilitate folding and to largely enhance halogen anion binding for an aryl-triazole foldamer.
N-Heterocyclic carbene palladium-catalyzed cascade annulation/alkynylation of 2-alkynylanilines with terminal alkynes
Authors: Li Jianxiao , Li Can , Ouyang Lu , Li Chunsheng , Wu Wanqing , Jiang Huanfeng
Published: September 2017

N-Heterocyclic carbene-palladium catalyzed cascade annulation/alkynylation for the assembly of various structurally diverse (NH)-3-alkynylindoles is described.
The templation effect as a driving force for the self-assembly of hydrogen-bonded peptidic capsules in competitive media
Authors: Grajda M. , Lewińska M. J. , Szumna A.
Published: September 2017

Complexation of a hydrophobic guest induces the self-assembly of peptide based cavitands to form hydrogen-bonded ordered capsules in polar solvents.
A new synthetic method for non-symmetric pillar[5]arenes with simple isolation and improved yield
Authors: Ding Jiaming , Chen Jiafu , Mao Weipeng , Huang Junrou , Ma Da
Published: September 2017

We developed a new synthetic method for non-symmetric pillar[n]arenes, which has improved yield and simple isolation.
Ring opening polymerization of macrolactones: high conversions and activities using an yttrium catalyst
Authors: Myers D. , Witt T. , Cyriac A. , Bown M. , Mecking S. , Williams C. K.
Published: September 2017

The ring-opening polymerization of macrolactones (C15–C23) is reported using an yttrium catalyst which shows high rates and conversions in the production of long-chain aliphatic polyesters.
Facile synthesis of poly(vinyl acetate)-b-polystyrene copolymers mediated by an iniferter agent using a single methodology
Authors: Wang Mengqi , Jiang Xiaowu , Luo Yanjing , Zhang Lifen , Cheng Zhenping , Zhu Xiulin
Published: September 2017

A novel and convenient method to synthesize diblock copolymers containing both conjugated and non-conjugated monomers, PVAc-b-PS, was established by using a single iniferter methodology.
Origin of surface potential in undoped zinc oxide films revealed by advanced scanning probe microscopy techniques
Authors: Su Ting
Published: September 2017

Surface potential of undoped ZnO film has been studied by a combined use of PFM and KPFM techniques.
Diastereoselective synthesis of benzo[d]chromeno[3′,4′:3,4]pyrrolo[2,1-b]thiazoles via cycloaddition reaction of benzothiazolium salts with 3-nitrochromenes
Authors: Jiang Wang , Sun Jing , Yan Chao-Guo
Published: September 2017

Diastereospecific synthesis of benzo[d]chromeno[3′,4′:3,4]pyrrolo[2,1-b]thiazoles via cycloaddition reaction of benzothiazolium salts with 3-nitrochromenes.
Design of micro-shell Cu–Al porous ceramometals as catalysts for the water–gas shift reaction
Authors: Tikhov S. , Minyukova T. , Valeev K. , Cherepanova S. , Salanov A. , Kaichev V. , Saraev A. , Andreev A. , Lapina O. , Sadykov V.
Published: September 2017

Development of a new type of ceramometal catalyst, CuAlO/CuAl, for WGS reaction with an oxide microshell.
Combining the catalytic enantioselective reaction of visible-light-generated radicals with a by-product utilization system
Authors: Huang Xiaoqiang , Luo Shipeng , Burghaus Olaf , Webster Richard D. , Harms Klaus , Meggers Eric
Published: September 2017

We report an unusual reaction design in which a chiral bis-cyclometalated rhodium(iii) complex enables the stereocontrolled chemistry of photo-generated carbon-centered radicals and at the same time catalyzes an enantioselective sulfonyl radical addition to an alkene.
Room temperature nanoparticulate interfacial layers for perovskite solar cells via solvothermal synthesis
Authors: Savva Achilleas , Papadas Ioannis T. , Tsikritzis Dimitris , Armatas Gerasimos S. , Kennou Stella , Choulis Stelios A.
Published: September 2017

Solvothermal synthesized CuO nanoparticles are implemented for the development of room temperature HTLs for highly efficient perovskite photovoltaics.
Environmentally safe, substrate-independent and repairable nanoporous coatings: large-scale preparation, high transparency and antifouling properties
Authors: Li Yong , Zhang Zhaozhu , Wang Mengke , Men Xuehu , Xue Qunji
Published: September 2017

Repairable and antifouling coatings were prepared via self-assembly method without destroying the intrinsic properties of substrates, which aims to tackle low transparency and poor durability problems of current coatings.
Monolithic laser scribed graphene scaffolds with atomic layer deposited platinum for the hydrogen evolution reaction
Authors: Nayak Pranati , Jiang Qiu , Kurra Narendra , Wang Xianbin , Buttner Ulrich , Alshareef Husam N.
Published: September 2017

Atomic layer deposition (ALD) of Pt over monolithic 3D porous, laser scribed graphene scaffolds forms an efficient electrocatalyst for the hydrogen evolution reaction.
Quantum material accompanied nonenzymatic cascade amplification for ultrasensitive photoelectrochemical DNA sensing
Authors: Wen Guangming , Yang Xiaojie , Wang Yongzhao
Published: September 2017

A novel cascade photoelectrochemical (PEC) signal amplification sensing strategy was designed and applied in target DNA detection by introducing quantum dots (QD) as the accompanying tag.
Tuning of luminescence color of π-conjugated liquid crystals through co-assembly with ionic liquids
Authors: Mitani Masato , Yoshio Masafumi , Kato Takashi
Published: September 2017

Excited intramolecular charge transfer states affect luminescence color of the supramolecular assembly formed by amphiphilic liquid crystals and ionic liquids.
A ligand divided: antagonist, agonist and analog control
Authors: Klein Daryl E.
Published: September 2017

Inhibiting receptor tyrosine kinases has been a cornerstone of cancer therapeutics for decades. Treatment strategies largely involve small-molecule kinase inhibitors and monoclonal antibodies. For receptors activated by constitutively dimeric ligands, another potential mechanism of inhibition exists: developing monomeric ligands that prevent receptor dimerization. In a recent issue of the Biochemical Journal, Zur et al. [Biochem. J. (2017) 474, 2601–2617] describe the details of creating such an inhibitor directed toward the macrophage colony-stimulating factor receptor, c-FMS. In the process of teasing apart the ligand dimer, they also uncover a potential cryptic regulatory mechanism in this receptor subfamily.
Single channel blind source separation based on probabilistic matrix factorisation
Authors: Kim Han‐Gyu , Jang Gil‐Jin , Park Jeong‐Sik , Oh Yung‐Hwan , Choi Ho‐Jin
Published: September 2017

A novel single channel blind source separation method based on probabilistic matrix factorisation (PMF) is proposed. Compared to the conventional non‐negative matrix factorisation (NMF) employing Euclidean distance or Kullback–Leibler divergence, PMF uses the log posterior probability as a cost function for optimising spectrum and activation matrices. Such cost function has an advantage that the hyperparameters are optimised numerically without cross‐validation. In order to apply PMF to audio source separation, both Gaussian and Laplacian priors are considered. Exponential substitution for target matrices is also proposed to guarantee the non‐negativity of the separated spectrogram. In source separation experiments, the proposed PMF‐based approach provided significantly better performance than the conventional NMF.
Fault‐tolerant formation control of non‐linear multi‐vehicle systems with application to quadrotors
Authors: Shi Jiantao , Yang Yuhao , Sun Jun , He Xiao , Zhou Donghua , Zhong Yisheng
Published: September 2017

This study is concerned with the fault‐tolerant (FT) formation control problem with a guaranteed performance for non‐linear multi‐vehicle systems subject to actuator faults. The authors consider a practical situation: the information transferred between adjacent vehicles is disturbed and each vehicle is interfered by stochastic disturbance and measurement noise. For each vehicle, a decentralised state observer and an adaptive fault estimator are designed based on which a novel cooperative FT control (FTC) protocol is proposed to drive all the vehicles to the desired formation configuration. Taking the system noise into consideration, the error dynamics are modelled by stochastic differential equations, whose properties are used for designing and analysing the Lyapunov function in the framework of calculus. It is proved that the formation error system is mean‐square asymptotically stable with a prescribed attenuation level in an sense by the proposed FTC scheme. The observer, estimator and controller gains can be obtained by solving algebraic Riccati inequalities. Finally, the theoretical results are illustrated by simulations and real experiments.
Decentralised adaptive control of a class of hidden leader–follower non‐linearly parameterised coupled MASs
Authors: Zhang Xinghong , Ma Hongbin , Yang Chenguang
Published: September 2017

In this study, decentralised adaptive control is investigated for a class of discrete‐time non‐linear hidden leader–follower multi‐agent systems (MASs). Different from the conventional leader–follower MAS, among all the agents, there exists a hidden leader that knows the desired reference trajectory, while the follower agents know neither the desired reference signal nor which is a leader agent. Each agent is affected from the history information of its own neighbours. The dynamics of each agent is described by the non‐linear discrete‐time auto‐regressive model with unknown parameters. In order to deal with the uncertainties and non‐linearity, a projection algorithm is applied to estimate the unknown parameters. Based on the certainty equivalence principle in adaptive control theory, the control for the hidden leader agent is designed by the desired reference signal, and the local control for each follower agent is designed using neighbourhood history information. Under the decentralised adaptive control, rigorous mathematical proofs are provided to show that the hidden leader agent tracks the desired reference signal, all the follower agents follow the hidden leader agent, and the closed‐loop system eventually achieves strong synchronisation in the presence of strong couplings. In the end, the simulation results show the validity of this scheme.
Dynamic forward error correction in wireless real‐time Internet of Things networks
Authors: Herrero Rolando , St‐Pierre Claude
Published: September 2017

Wireless sensor and actuator networks (WSAN) have greatly benefited from the latest development in real‐time Internet of Things standardisation efforts. Specifically, the Internet Engineering Task Force Constrained Application Protocol (CoAP) is one of the preferred mechanisms that provide session transport in the context of low‐power low‐rate networks in general and WSAN in particular. CoAP, that relies on traditional user datagram protocol, introduces a particular mode of operation, known as non‐confirmable, that minimises latency but it is highly sensitive to network packet loss. The use of forced forward error correction (FEC), although efficient at reducing packet loss, excessively increases the session throughput. The authors introduce an algorithm that dynamically manages FEC minimising application layer packet loss while keeping throughput under control. The mechanism is evaluated through an experimental framework where traditional CoAP, forced FEC CoAP and dynamic FEC CoAP implementations are compared.
Design and Synthesis of an RGD Peptidomimetic-Paclitaxel Conjugate Targeting αvβ3 Integrin for Tumour-Directed Drug Delivery
Authors: Piras Monica , Andriu Alexandra , Testa Andrea , Wienecke Paul , Fleming Ian , Zanda Matteo
Published: September 2017

A 1,2,3-triazole-based RGD peptidomimetic having nanomolar affinity for αvβ3 integrin was conjugated to the potent antimitotic paclitaxel via an oxime heterobifunctional linker. The resulting construct maintained nanomolar binding concentration to αvβ3 integrin and showed 11-fold selectivity in terms of cytotoxicity towards highly αvβ3 expressing U87MG cancer cells relative to non αvβ3 expressing MCF7 cells, indicating promising cancer cell targeting capacity.

1 Design

2 Retrosynthesis

3 Synthesis

4 Solid-Phase Receptor Binding Assay

5 Cell Cytotoxicity Assays

6 Metabolic Stability Assays

7 Conclusions
Arterial Spin Labeling—Can Neurointerventionists Rely on This Novel Technique? A Case Series on Successful Use of Arterial Spin Labeling in Acute Stroke Imaging
Authors: Rahul K. , Santhosh P. , Kumar M. , Mehta Pankaj , Cherian Mathew
Published: September 2017

Presence of ischemic penumbra is the principal factor that decides the need for mechanical thrombectomy in acute stroke patients with large vessel occlusion. Our objective was to evaluate the usefulness of arterial spin labeling (ASL) in detecting diffusion perfusion mismatch and directing patients into mechanical thrombectomy. We retrospectively studied all patients with acute nonhemorrhagic stroke in the anterior circulation, who had undergone stroke imaging with ASL followed by mechanical thrombectomy from July 2016 to November 2016. Area of diffusion perfusion mismatch was graded semiquantitatively into three grades: small, medium, and large. Mismatch was compared with 30-day modified Rankin scale (mRS) score. Interpretable PASL-perfusion images were obtained in all patients. Diffusion perfusion mismatches were present in all patients. Out of six patients with good mRS score, five patients had large diffusion perfusion mismatch. Two out of three patients with poor mRS were secondary to failed recanalization, in spite of large mismatch. One out of nine patients had poor outcome as well as a small area of mismatch. ASL is a rapid noninvasive imaging technique in acute stroke that has got the potential to detect ischemic penumbra.
Do You Know Your Lines?
Authors: Rachapalli Vamsidhar , Sharma Pankaj , Kumar Sheo , Uthappa Mangerira
Published: September 2017

The use of central venous catheters has become ubiquitous in the clinical practice. While a majority of them are easy to insert, many consider it a mundane interventional procedure. However, it is important to ensure that the right catheter is selected for the right patient. In addition, due diligence should be observed during site selection and catheter securement. This article briefly but concisely covers various aspects of venous catheter insertion ranging from catheter selection, patient preparation, choice of skin antisepsis to catheter tip position. This article, however, does not deal with the actual steps involved in the insertion of various catheters.
Sirtuin 1 Levels in Recurrent Implantation Failure
Authors: Engin-Ustun Yaprak , Ozgu-Erdinc A. Seval , Kiyak Caglayan Emel , Gulerman Cavidan , Sarikaya Esma , Aktulay Ayla , Demirtas Canan , Erkaya Salim , Yilmaz Nafiye
Published: September 2017

Sirtuin 1 has an important role in cellular processes, including apoptosis and cellular stress. The purpose of this study was to assess serum sirtuin 1 levels in women with recurrent implantation failure (RIF). In this cross-sectional study, we included 28 women with RIF, 29 healthy women who had conceived by in vitro fertilization (IVF), and 30 women with a 1-cycle failure of IVF as controls. Human serum nicotinamide adenine dinucleotide (NAD)-dependent deacetylase sirtuin-1 (SIRT1/SIRT2L1) levels were detected using a commercial colorimetric kit. Recurrent implantation failure patients have higher sirtuin 1 levels than non-pregnant women and healthy pregnant women, but this difference did not reach statistical significance due to the low number of patients in our study. These higher sirtuin 1 levels may result from the inflammation imbalance of RIF patients. The only statistically significant correlation found was between age and sirtuin (r = 0.277, p = 0.009).
Neue Antidiabetika und kardiovaskuläre Outcome-Studien
Authors: Seufert Jochen , Laubner Katharina
Published: September 2017

Type 2 diabetes mellitus (T2DM) represents a major risk factor for the development of cardiovascular events, and cardiovascular mortality determines overall mortality in these patients. So far, glucose lowering per se has demonstrated a small effect in reduction of cardiovascular risk in T2DM patients. Due to regulatory purposes, since 2008 all novel antidiabetic medications, such as DPP4 inhibitors, GLP-1 receptor agonists and SGLT2 inhibitors are investigated in dedicated cardiovascular outcome trials to demonstrate cardiovascular safety (non-inferiority trials). While the currently completed cardiovascular outcome trials for the DPP4 inhibitors sitagliptin, saxagliptin and alogliptin consistently demonstrated a neutral effect on cardiovascular risk, those trials for the GLP-1 receptor agonists revealed differential outcomes. Lixisenatide effects were neutral on cardiovascular outcomes while Liraglutide and Semaglutide demonstrated a reduction in cardiovascular risk. Most impressively was cardiovascular mortality, overall mortality and hospitalisation for heart failure reduced by the SGLT2 inhibitor empagliflozin in its dedicated outcome trial. These results strongly imply that certain novel antihyperglycaemic agents bear the potential to strongly reduce cardiovascular risk in patients with T2DM beyond their glucose lowering potency. The potential to reduce cardiovascular risk in patients with T2DM will selectively determine the clinical application of antidiabetic medications in the future.
Magdalena Ruranski – „Wie es ist, mit Borderline zu leben? Anstrengend“
Authors: Becker Marion
Published: September 2017

Die 31-jährige Ergotherapeutin hat eine Borderline-Persönlichkeitsstörung (BPS). Seit der Diagnose ist sie vielen Vorurteilen begegnet – selbst im Ergotherapiestudium. Deshalb hat sie beschlossen, über ihre Krankheit zu sprechen. Um aufzuklären und Missverständnisse aus dem Weg zu räumen. Auch unter Therapeuten.
Gemeinsam forschen – gemeinsam handeln
Authors: Katalinic Alexander , Krause Gérard , Geyer Siegfried , Moebus Susanne
Published: September 2017

Im „Dictionary of Epidemiology“, herausgegeben von der International Epidemiological Association (IEA), wird Epidemiologie wie folgt definiert: „Epidemiology – The study of the occurrence and distribution of health-related events, states, and processes in specified populations, including the study of the determinants influencing such processes, and the application of this knowledge to control relevant health problems” 1.
“It fixates”: indie quiets and the new Gothics
Authors: Hawkins Joan
Published: September 2017

The article attempts to make several interventions. Following Jamie Sexton’s work on Independent Horror, it revisits the vexed status of horror within American Independent Cinema. Not only is indie horror frequently omitted from discussion of American Independent Cinema, but low budget, direct-to-DVD and video-on-demand indie horror titles are frequently omitted from academic discussions of horror. This has the effect of skewing our understanding of the genre. From there the article moves to consider a specific subgenre of indie horror that has been gaining in popularity: the Quiet Horror film—a category that contains the sub-genre of indie-Gothic films. Lastly, the paper moves on to a close reading of a specific low budget indie Gothic title, Absentia.
Self-propagating waves of crystallization in metallic glasses
Authors: Rogachev A. S. , Vadchenko S. G. , Aronin A. S. , Rouvimov S. , Nepapushev A. A. , Kovalev I. D. , Baras F. , Politano O. , Rogachev S. A. , Mukasyan A. S.
Published: September 2017

Self-propagating thermal waves of the amorphous-crystalline transformation in Fe-based metallic glasses, obtained by melt spinning, were observed using a high-speed infrared camera and reported here. Some experimental results are also reported concerning oscillating waves in the CuTi glassy foils. The thermal characteristics and wave propagating velocities, as well as the microstructure and atomic structure transformations, were studied. A comparison of the results with exothermic reaction waves and explosive crystallization shows that the self-propagating waves in metallic glasses are slower and less violent than classical explosive crystallization in deposited films; thus, we suggest naming this phenomenon “soft explosive crystallization.” The experimental data were confirmed by molecular dynamics simulation of the crystallization phenomenon.
Microscale magnetic compasses
Authors: Shiozawa Hidetsugu , Zhang Desai , Eisterer Michael , Ayala Paola , Pichler Thomas , McCartney Martha R. , Smith David J.
Published: September 2017

Microscale magnetic compasses have been synthesized with high yield. These ferromagnetic iron carbide nano-particles, which are encapsulated in a pair of parallel carbon needles, change their orientation in response to an external magnetic field. Electron holography reveals magnetic fields confined to the vicinity of the bicone-shaped particles, which are composed of only a few ferromagnetic domains. Aligned magnetically and encapsulated in an acrylate polymer matrix, these micro-compasses exhibit anisotropic bulk magnetic permeability with an easy axis normal to the needle direction that can be understood as a result of the anisotropic demagnetizing field of a non-spherical single-domain particle. This novel type of material with orthogonal magnetic and structural axes could be highly useful as magnetic components in electromagnetic wave absorbent materials and magnetorheological fluids.
IR spectroscopic study of the displacement of an SF6 monolayer on graphite by Xe
Authors: Hess G. B. , Xia Yu
Published: September 2017

We report a study of displacement by xenon of a monolayer of sulphur hexafluoride initially condensed on a graphite surface. Earlier work showed that, below 112 K, Xe displaces SF6 almost completely in a first-order transition. Working at higher temperatures, we show that this system has a simple eutectic-like phase diagram, at least for SF6 not too dilute. In our experiment, both adsorbates are in equilibrium with their respective vapors in a cold cell. In our infrared reflection-absorption spectroscopy measurements, the SF6 coverage on the surface is monitored by the frequency shift due to dynamic dipole coupling of the collective mode of the strong SF6 ν3 vibrational resonance. Simulations relate this frequency shift to the SF6 areal density. Below T ≈ 134 K, with increasing Xe pressure, a small amount Xe dissolves in the solid SF6 monolayer preceding its displacement by a solid predominantly Xe monolayer in a first-order transition. Above 134 K, there is a weaker first-order transition to a mixed liquid monolayer, followed by continuous increase in Xe concentration. If the initial SF6 monolayer is near its melting line, the melting transition on adding Xe appears to become continuous.
Calculation of electrical conductivity of fast discharges in nitrogen gas using the performance of a transversely excited N2 laser
Authors: Panahibakhsh S. , Hariri A.
Published: September 2017

Rate equations of a low pressure transversely excited (TE) nitrogen laser with variable electrode lengths and gap separations, along with the relevant equations for the electrical circuit, drift velocity, and Townsend ionization coefficients, are used to study the electrical conductivity of the low-ionized nitrogen gas. Two different functional dependencies of drift velocity and the Townsend coefficient of nitrogen gas on the ratio of the electric field to gas pressure, E/p, are used for the calculation. The results show that the electrical conductivity in the fast electric discharge of a few nanosecond time-scales is time and space dependent. For the low selected range of the E/p-value, the electrical conductivity and small-signal-gain behave similarly. For the high selected range of the E/p-value, on the other hand, it is observed that by increasing time and electron temperature, the electrical conductivity, corresponding to the discharge between two electrodes, enhances highly near the cathode for any excitation lengths. The dependencies of the electrical conductivity on gas pressure, electron temperature, gap separation, and electrode length are illustrated. The time behavior of the electrical conductivity and the gas resistance are also presented. This is the first report on the calculation of the electrical conductivity, where the performance of a TE gas laser is used to obtain the transient as well as the steady state behaviors of the electrical conductivity corresponding to a few ten nanosecond electric discharge in nitrogen gas. Details of the numerical calculation will be given in this report.
Human eye visual hyperacuity: Controlled diffraction for image resolution improvement
Authors: Lagunas A. , Domínguez O. , Martinez-Conde S. , Macknik S. L. , Del-Río C.
Published: September 2017

The Human Visual System appears to be using a low number of sensors for image capturing, and furthermore, regarding the physical dimensions of cones—photoreceptors responsible for the sharp central vision—we may realize that these sensors are of a relatively small size and area. Nonetheless, the human eye is capable of resolving fine details thanks to visual hyperacuity and presents an impressive sensitivity and dynamic range when set against conventional digital cameras of similar characteristics. This article is based on the hypothesis that the human eye may be benefiting from diffraction to improve both image resolution and acquisition process. The developed method involves the introduction of a controlled diffraction pattern at an initial stage that enables the use of a limited number of sensors for capturing the image and makes possible a subsequent post-processing to improve the final image resolution.
Combined selective emitter and filter for high performance incandescent lighting
Authors: Leroy Arny , Bhatia Bikram , Wilke Kyle , Ilic Ognjen , Soljačić Marin , Wang Evelyn N.
Published: September 2017

The efficiency of incandescent light bulbs (ILBs) is inherently low due to the dominant emission at infrared wavelengths, diminishing its popularity today. ILBs with cold-side filters that transmit visible light but reflect infrared radiation back to the filament can surpass the efficiency of state-of-the-art light-emitting diodes (LEDs). However, practical challenges such as imperfect geometrical alignment (view factor) between the filament and cold-side filters can limit the maximum achievable efficiency and make the use of cold-side filters ineffective. In this work, we show that by combining a cold-side optical filter with a selective emitter, the effect of the imperfect view factor between the filament and filter on the system efficiency can be minimized. We experimentally and theoretically demonstrate energy savings of up to 67% compared to a bare tungsten emitter at 2000 K, representing a 34% improvement over a bare tungsten filament with a filter. Our work suggests that this approach can be competitive with LEDs in both luminous efficiency and color rendering index (CRI) when using selective emitters and filters already demonstrated in the literature, thus paving the way for next-generation high-efficiency ILBs.
Compositing orbital angular momentum beams in Bi4Ge3O12 crystal for magnetic field sensing
Authors: Yu Shuangfeng , Pang Fufei , Liu Huanhuan , Li Xianjin , Yang Junfeng , Wang Tingyun
Published: September 2017

The polarization states and orbital angular momentum (OAM) properties of light are of considerable importance for several aspects of high-precision optical measurements. In this work, we have investigated the properties of composited OAM beams propagating in a Bi4Ge3O12 crystal under an applied magnetic field and have demonstrated a magnetic field sensing method based on compositing of OAM beams using a Sagnac configuration. The polarization rotation can be projected into petal-like patterns by the rotation of the OAM beams. However, the accurate measurement of the rotation angles of the petal-like patterns of OAM beams remains challenging. Therefore, an image processing technique based on the Radon transform is explored to enable the accurate calculation of the rotation angle of the petal-like patterns of composite OAM beams under different magnetic fields. The rotation angle of these petal-like patterns is found to have a linear dependence on the magnetic field intensity, which means that the proposed system is appropriate for magnetic field sensing applications. Using this method, a magnetic field sensitivity of 28°/T has been achieved experimentally with a measurement error of 0.0123 T in a high-intensity magnetic field ranging from 191 to 3322 G for OAM beams with topological charge (TC) l=±1.
Coarsening and aging of lattice polymers: Influence of bond fluctuations
Authors: Christiansen Henrik , Majumder Suman , Janke Wolfhard
Published: September 2017

We present results for the nonequilibrium dynamics of collapse for a model flexible homopolymer on simple cubic lattices with fixed and fluctuating bonds between the monomers. Results from our Monte Carlo simulations show that, phenomenologically, the sequence of events observed during the collapse are independent of the bond criterion. While the growth of the clusters (of monomers) at different temperatures exhibits a non-universal power-law behavior when the bonds are fixed, the introduction of fluctuations in the bonds by considering the existence of diagonal bonds produces a temperature independent growth, which can be described by a universal nonequilibrium finite-size scaling function with a non-universal metric factor. We also examine the related aging phenomenon, probed by a suitable two-time density-density autocorrelation function showing a simple power-law scaling with respect to the growing cluster size. Unlike the cluster-growth exponent αc, the nonequilibrium autocorrelation exponent λC governing the aging during the collapse, however, is independent of the bond type and strictly follows the bounds proposed by Majumder and Janke [Phys. Rev. E 93, 032506 (2016)] at all temperatures.
Signatures of vibronic coupling in two-dimensional electronic-vibrational and vibrational-electronic spectroscopies
Authors: Gaynor James D. , Khalil Munira
Published: September 2017

Two-Dimensional Electronic-Vibrational (2D EV) spectroscopy and Two-Dimensional Vibrational-Electronic (2D VE) spectroscopy are new coherent four-wave mixing spectroscopies that utilize both electronically resonant and vibrationally resonant field-matter interactions to elucidate couplings between electronic and vibrational degrees of freedom. A system Hamiltonian is developed here to lay a foundation for interpreting the 2D EV and 2D VE signals that arise from a vibronically coupled molecular system in the condensed phase. A molecular system consisting of one anharmonic vibration and two electronic states is modeled. Equilibrium displacement of the vibrational coordinate and vibrational frequency shifts upon excitation to the first electronic excited state are included in our Hamiltonian through linear and quadratic vibronic coupling terms. We explicitly consider the nuclear dependence of the electronic transition dipole moment and demonstrate that these spectroscopies are sensitive to non-Condon effects. A series of simulations of 2D EV and 2D VE spectra obtained by varying parameters of the system, system-bath, and interaction Hamiltonians demonstrate that one of the following conditions must be met to observe signals: (1) non-zero linear and/or quadratic vibronic coupling in the electronic excited state, (2) vibrational-coordinate dependence of the electronic transition dipole moment, or (3) electronic-state-dependent vibrational dephasing dynamics. We explore how these vibronic interactions are manifested in the positions, amplitudes, and line shapes of the peaks in 2D EV and 2D VE spectroscopies.
The regime of large bubble entrapment during a single drop impact on a liquid pool
Authors: Deka Hiranya , Ray Bahni , Biswas Gautam , Dalal Amaresh , Tsai Pei-Hsun , Wang An-Bang
Published: September 2017

The present study focuses on the identification of the large bubble entrapment regime on the V-D map and on the We-Fr map together with the detailed analysis of the mechanism of large bubble entrapment. The sequential large and small bubble entrapment previously found by Wang, Kuan, and Tsai [“Do we understand the bubble formation by a single drop impacting upon liquid surface?,” Phys. Fluids 25, 101702 (2013)] has been observed in this investigation. Large bubble entrapment is observed only for prolate-shaped drops. Prolate shaped drops bring about deeper penetration of the vortex ring into the pool. The emergence of an ejecta sheet that leads to lamella prevents the penetration of the vortex ring and thus prevents the large bubble entrapment. The entrapment of a large bubble is always accompanied by an inward jet and an upward jet. The inward jet penetrates through the bubble and deforms the bubble shape. A thorough parametric study has been conducted numerically and experimentally on the crater dynamics and its dependence on the initial condition of the drop at the instance of impact.
Unique lift-off of droplet impact on high temperature nanotube surfaces
Authors: Tong Wei , Qiu Lu , Jin Jian , Sun Lidong , Duan Fei
Published: September 2017

A unique liquid film lift-off during a falling water droplet impacting on a heated titanium oxide nanotube surface has been experimentally revealed through a high speed visualization system. It is suggested that the Leidenfrost point on the nanotube surface has been significantly delayed, as compared to that on the bare titanium surface. Such delay is inferred to be a result of the increase in the surface wettability and the capillary effect by the nanoscale tube structure. By measuring the liquid lift-off distance from the substrate surface, a droplet lift-off is typically divided into four stages, namely, first contact, first lift-off, second contact, and second lift-off. The residence time at each stage is quantitatively evaluated. As the surface temperature increases, the duration time is significantly reduced for both the first contact and the first lift-off stages.
On the importance of minimizing “coast-time” in x-ray driven inertially confined fusion implosions
Authors: Hurricane O. A. , Kritcher A. , Callahan D. A. , Landen O. , Patel P. K. , Springer P. T. , Casey D. T. , Dewald E. L. , Dittrich T. R. , Döppner T. , Hinkel D. E. , Berzak Hopkins L. F. , Kline J. , Le Pape S. , Ma T. , MacPhee A. G. , Moore A. , Pak A. , Park H.-S. , Ralph J. , Salmonson J. D. , Widmann K.
Published: September 2017

By the time an inertially confined fusion (ICF) implosion has converged a factor of 20, its surface area has shrunk 400×, making it an inefficient x-ray energy absorber. So, ICF implosions are traditionally designed to have the laser drive shut off at a time, toff, well before bang-time, tBT, for a coast-time of tcoast=tBT−toff>1 ns. High-foot implosions on NIF showed a strong dependence of many key ICF performance quantities on reduced coast-time (by extending the duration of laser power after the peak power is first reached), most notably stagnation pressure and fusion yield. Herein we show that the ablation pressure, pabl, which drives high-foot implosions, is essentially triangular in temporal shape, and that reducing tcoast boosts pabl by as much as ∼2× prior to stagnation thus increasing fuel and hot-spot compression and implosion speed. One-dimensional simulations are used to track hydrodynamic characteristics for implosions with various coast-times and various assumed rates of hohlraum cooling after toff to illustrate how the late-time conditions exterior to the implosion can impact the fusion performance. A simple rocket model-like analytic theory demonstrates that reducing coast-time can lead to a ∼15% higher implosion velocity because the reduction in x-ray absorption efficiency at late-time is somewhat compensated by small (∼5%−10%) ablator mass remaining. Together with the increased ablation pressure, the additional implosion speed for short coast-time implosions can boost the stagnation pressure by ∼2× as compared to a longer coast-time version of the same implosion. Four key dimensionless parameters are identified and we find that reducing coast-time to as little as 500 ps still provides some benefit. Finally, we show how the high-foot implosion data is consistent with the above mentioned picture.
Atomistic simulations on ductile-brittle transition in ⟨111⟩ BCC Fe nanowires
Authors: Sainath G. , Choudhary B. K.
Published: September 2017

Molecular dynamics simulations have been performed to understand the influence of temperature on the tensile deformation and fracture behavior of ⟨111⟩ BCC Fe nanowires. The simulations have been carried out at different temperatures in the range 10–1000 K employing a constant strain rate of 1 × 108 s−1. The results indicate that at low temperatures (10–375 K), the nanowires yield through the nucleation of a sharp crack and fails in brittle manner. On the other hand, nucleation of multiple 1/2⟨111⟩ dislocations at yielding followed by significant plastic deformation leading to ductile failure has been observed at high temperatures in the range 450–1000 K. At 400 K, the nanowire yields through nucleation of crack associated with many mobile 1/2⟨111⟩ and immobile ⟨100⟩ dislocations at the crack tip and fails in ductile manner. The ductile-brittle transition observed in ⟨111⟩ BCC Fe nanowires is appropriately reflected in the stress-strain behavior and plastic strain at failure. The ductile-brittle transition increases with increasing nanowire size. The change in fracture behavior has been discussed in terms of the relative variations in yield and fracture stresses and change in slip behavior with respect to temperature. Further, the dislocation multiplication mechanism assisted by the kink nucleation from the nanowire surface observed at high temperatures has been presented.
Testing the nature of reaction coordinate describing interaction of H2 with carbonyl carbon, activated by Lewis acid complexation, and the Lewis basic solvent: A Born-Oppenheimer molecular dynamics study with explicit solvent
Authors: Heshmat Mojgan , Privalov Timofei
Published: September 2017

Using Born-Oppenheimer molecular dynamics (BOMD), we explore the nature of interactions between H2 and the activated carbonyl carbon, C(carbonyl), of the acetone-B(C6F5)3 adduct surrounded by an explicit solvent (1,4-dioxane). BOMD simulations at finite (non-zero) temperature with an explicit solvent produced long-lasting instances of significant vibrational perturbation of the H—H bond and H2-polarization at C(carbonyl). As far as the characteristics of H2 are concerned, the dynamical transient state approximates the transition-state of the heterolytic H2-cleavage. The culprit is the concerted interactions of H2 with C(carbonyl) and a number of Lewis basic solvent molecules—i.e., the concerted C(carbonyl)⋯H2⋯solvent interactions. On one hand, the results presented herein complement the mechanistic insight gained from our recent transition-state calculations, reported separately from this article. But on the other hand, we now indicate that an idea of the sufficiency of just one simple reaction coordinate in solution-phase reactions can be too simplistic and misleading. This article goes in the footsteps of the rapidly strengthening approach of investigating molecular interactions in large molecular systems via “computational experimentation” employing, primarily, ab initio molecular dynamics describing reactants-interaction without constraints of the preordained reaction coordinate and/or foreknowledge of the sampling order parameters.
Critical size dependence of domain formation observed in coarse-grained simulations of bilayers composed of ternary lipid mixtures
Authors: Pantelopulos George A. , Nagai Tetsuro , Bandara Asanga , Panahi Afra , Straub John E.
Published: September 2017

Model cellular membranes are known to form micro- and macroscale lipid domains dependent on molecular composition. The formation of macroscopic lipid domains by lipid mixtures has been the subject of many simulation investigations. We present a critical study of system size impact on lipid domain phase separation into liquid-ordered and liquid-disordered macroscale domains in ternary lipid mixtures. In the popular di-C16:0 PC:di-C18:2 PC:cholesterol at 35:35:30 ratio mixture, we find systems with a minimum of 1480 lipids to be necessary for the formation of macroscopic phase separated domains and systems of 10 000 lipids to achieve structurally converged conformations similar to the thermodynamic limit. To understand these results and predict the behavior of any mixture forming two phases, we develop and investigate an analytical Flory-Huggins model which is recursively validated using simulation and experimental data. We find that micro- and macroscale domains can coexist in ternary mixtures. Additionally, we analyze the distributions of specific lipid-lipid interactions in each phase, characterizing domain structures proposed based on past experimental studies. These findings offer guidance in selecting appropriate system sizes for the study of phase separations and provide new insights into the nature of domain structure for a popular ternary lipid mixture.
Control of propagating spin-wave attenuation by the spin-Hall effect
Authors: Woo Seonghoon , Beach Geoffrey S. D.
Published: September 2017

The spin-Hall effect induced modification of the attenuation of propagating exchange-mode spin waves (SWs) is studied micromagnetically and analytically in heavy-metal/ferromagnet bilayers. Micromagnetic simulations of spin-wave propagation in Pt/NiFe show that at a relatively low current density of ∼ 6 × 1011 A/m2, Gilbert damping is exactly balanced by the spin-Hall torque and long-distance SW transmission is possible. An analytical model is developed to explain the micromagnetic results and relate the current density to the characteristic attenuation length. The results suggest that the spin Hall effect can be used as an effective means to control the attenuation length of propagating spin waves in nanostructures.
Unsteady electrorotation of a drop in a constant electric field
Authors: Tyatyushkin Alexander N.
Published: September 2017

The unsteady electrorotation of a drop of a viscous weakly conducting polarizable liquid suspended in another viscous weakly conducting polarizable liquid immiscible with the former in an applied constant uniform electric field is theoretically investigated. The surface tension of the drop is regarded as sufficiently large for deformation of the drop under the action of the applied electric field and the electrohydrodynamic flow can be considered small and the drop can be considered spherical in the calculation of the electric field and flow. The electric field intensity and the velocity and pressure in the electrohydrodynamic flow are sought for in the form of a series solution with time-dependent scalar, vector, and tensor coefficients for which relations are found allowing one to determine them. The coefficients are sought for in the form of asymptotic expansions over the parameter, the smallness of which corresponds to the sufficiently large viscosity of the drop with respect to that of the surrounding liquid. The differential equations for the terms of the dimensionless expansions up to the first and second orders with respect to this parameter are obtained. Their stationary solutions are found in the explicit form and their stability is investigated. Up to the terms of the second order, transitions to deformational oscillations of the drop are established not to occur.
Application of nonuniform magnetic fields in a Brownian dynamics model of ferrofluids with an iterative constraint scheme to fulfill Maxwell’s equations
Authors: Dubina Sean Hyun , Wedgewood Lewis Edward
Published: September 2017

Ferrofluids are steadily rising in applications across many fields, preferred for their ability to be remotely positioned and controlled via external magnetic fields. In magnetic separation operations, nonuniform magnetic fields elicit a phenomenon known as magnetophoresis so that the ferroparticles will undergo migration toward areas of higher magnetism. To comprehend this behavior, the authors developed a Brownian dynamics simulation of particles in ferromagnetic clusters under the influences of a simple shear flow and an applied magnetic field gradient. An iterative constraint mechanism was implemented to satisfy Maxwell’s equations throughout the dense colloidal suspension, ensuring that essential laws of magnetostatics are rigorously fulfilled at all times over small, finite sub-volumes of the system. Because of the presence of nonuniform magnetic fields, magnetophoresis and magnetic separation behavior were analyzed to assess the effectiveness of the model. Results showed that, when compared to “unconstrained” models, separation caused by magnetic field gradients occurred at a decreased rate under the constraint scheme due to relatively weaker non-Newtonian aggregation property trends. Through application of a dimensionless number analysis to observe varied levels of particle-particle interactions, thermal fluctuations, and viscous shearing, it was confirmed that the aggregation and magnetic separation modeling of ferrofluid colloidal suspensions without acceptable adherence to Maxwell’s equations produces an unreliable representation of current ferrofluids.