bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum Exosome MicroRNA as a Minimally-Invasive Early Biomarker of AML
Authors: Hornick Noah I. , Huan Jianya , Doron Ben , Goloviznina Natalya A. , Lapidus Jodi , Chang Bill H. , Kurre Peter
Published: June 2015

Relapse remains the major cause of mortality for patients with Acute Myeloid Leukemia (AML). Improved tracking of minimal residual disease (MRD) holds the promise of timely treatment adjustments to preempt relapse. Current surveillance techniques detect circulating blasts that coincide with advanced disease and poorly reflect MRD during early relapse. Here, we investigate exosomes as a minimally invasive platform for a microRNA (miRNA) biomarker. We identify a set of miRNA enriched in AML exosomes and track levels of circulating exosome miRNA that distinguish leukemic xenografts from both non-engrafted and human CD34+ controls. We develop biostatistical models that reveal circulating exosomal miRNA at low marrow tumor burden and before circulating blasts can be detected. Remarkably, both leukemic blasts and marrow stroma contribute to serum exosome miRNA. We propose development of serum exosome miRNA as a platform for a novel, sensitive compartment biomarker for prospective tracking and early detection of AML recurrence.
Prevalence and clinical correlates of somatic mutation in aldosterone producing adenoma-Taiwanese population
Authors: Wu Vin-Cent , Huang Kuo-How , Peng Kang-Yung , Tsai Yao-Chou , Wu Che-Hsiung , Wang Shuo-Meng , Yang Shao-Yu , Lin Lian-Yu , Chang Chin-Chen , Lin Yen-Hung , Lin Shuei-Liong , Chu Tzong-Shinn , Wu Kwan-Dun
Published: June 2015

Primary aldosteronism (PA) is a common form of secondary hypertension and has significant cardiovascular consequences. Mutated channelopathy due to the activation of calcium channels has been recently described in aldosterone-producing adenoma (APA). The study involved 148 consecutive PA patients, (66 males; aged 56.3 ± 12.3years) who received adrenalectomy and were collected from the Taiwan PA investigator (TAIPAI) group. A high rate of somatic mutation in APA was found (n = 91, 61.5%); including mutations in KCNJ5 (n = 88, 59.5%), ATP1A1 (n = 2, 1.4%) and ATP2B3 (n = 1, 0.7%); however, no mutations in CACNA1D were identified. Mutation-carriers were younger (<0.001), had lower Cyst C (p = 0.042), pulse wave velocity (p = 0.027), C-reactive protein (p = 0.042) and a lower rate of proteinuria (p = 0.031) than non-carriers. After multivariate adjustment, mutation carriers had lower serum CRP levels than non-carriers (p = 0.031. Patients with mutation also had a greater chance of recovery from hypertension after operation (p = 0.005). A high incidence of somatic mutations in APA was identified in the Taiwanese population. Mutation-carriers had lower CRP levels and a higher rate of cure of hypertension after adrenalectomy. This raises the possibility of using mutation screening as a tool in predicting long-term outcome after adrenalectomy.
TRRUST: a reference database of human transcriptional regulatory interactions
Authors: Han Heonjong , Shim Hongseok , Shin Donghyun , Shim Jung Eun , Ko Yunhee , Shin Junha , Kim Hanhae , Cho Ara , Kim Eiru , Lee Tak , Kim Hyojin , Kim Kyungsoo , Yang Sunmo , Bae Dasom , Yun Ayoung , Kim Sunphil , Kim Chan Yeong , Cho Hyeon Jin , Kang Byunghee , Shin Susie , Lee Insuk
Published: June 2015

The reconstruction of transcriptional regulatory networks (TRNs) is a long-standing challenge in human genetics. Numerous computational methods have been developed to infer regulatory interactions between human transcriptional factors (TFs) and target genes from high-throughput data and their performance evaluation requires gold-standard interactions. Here we present a database of literature-curated human TF-target interactions, TRRUST (transcriptional regulatory relationships unravelled by sentence-based text-mining, http://www.grnpedia.org/trrust), which currently contains 8,015 interactions between 748 TF genes and 1,975 non-TF genes. A sentence-based text-mining approach was employed for efficient manual curation of regulatory interactions from approximately 20 million Medline abstracts. To the best of our knowledge, TRRUST is the largest publicly available database of literature-curated human TF-target interactions to date. TRRUST also has several useful features: i) information about the mode-of-regulation; ii) tests for target modularity of a query TF; iii) tests for TF cooperativity of a query target; iv) inferences about cooperating TFs of a query TF; and v) prioritizing associated pathways and diseases with a query TF. We observed high enrichment of TF-target pairs in TRRUST for top-scored interactions inferred from high-throughput data, which suggests that TRRUST provides a reliable benchmark for the computational reconstruction of human TRNs.
Greener Solvent Usage for Discovery Chemistry Analysis and Purification
Authors: Miller Larry , Peterson Emily A.
Published: June 2015

The concept of green chemistry has been implemented in chemical manufacturing and process chemistry over the past 15 years. Only recently has the concept been introduced to smaller volume activities such as medicinal and analytical chemistry. This chapter discusses green chemistry approaches suitable for discovery chemistry analysis and purification. Topics covered include use of supercritical fluid chromatography (SFC) for analysis and purification to reduce solvent usage, optimizing analytical LC methods to minimize solvent usage, optimization of reverse phase purifications, use of greener solvents for flash purification, and an evaluation of flash SFC for discovery chemistry purifications. Approaches that have been successful in numerous pharmaceutical medicinal chemistry laboratories will be presented.
Continuous Processing in Drug Discovery
Authors: Belecki Katherine , Gupton B. Frank
Published: June 2015

The ability to produce a broad range of pharmacophores is an enabling element of the drug discovery process. Continuous chemical processing offers the opportunity to access synthons that are unavailable through traditional batch methods. Herein we report an overview of continuous synthetic methods, instrumentation, and green processing strategies that can be used to aid in preparation of new chemical entities.
Fluorine teams up with water to restore inhibitor activity to mutant BPTI
Authors: Ye Shijie , Loll Bernhard , Berger Allison Ann , Mülow Ulrike , Alings Claudia , Wahl Markus Christian , Koksch Beate
Published: June 2015

Fluorinated derivatives of aminobutyric acid engage in unique interactions with structural waters within the BPTI/trypsin interface and restore inhibitor activity.
Spectroscopic analysis and in vitro imaging applications of a pH responsive AIE sensor with a two-input inhibit function
Authors: Zhou Zhan , Gu Fenglong , Peng Liang , Hu Ying , Wang Qianming
Published: June 2015

A novel terpyridine derivative formed stable aggregates in aqueous media (DMSO/H2O = 1/99) with dramatically enhanced fluorescence compared to its organic solution.
Effective Am(iii)/Eu(iii) separations using 2,6-bis(1,2,4-triazin-3-yl)pyridine (BTP) functionalised titania particles and hierarchically porous beads
Authors: Veliscek-Carolan J. , Jolliffe K. A. , Hanley T. L.
Published: June 2015

Titania particles and beads functionalised with a modified BTP ligand have been used to selectively extract Am(iii) over Eu(iii) from 0.01 M nitric acid solutions.
An Au(i)-catalyzed rearrangement/cyclization cascade toward the synthesis of 2-substituted-1,4,5,6-tetrahydrocyclopenta[b]pyrrole
Authors: Mou Xue-Qing , Xu Zheng-Liang , Wang Shao-Hua , Zhu Dao-Yong , Wang Jie , Bao Wen , Zhou Shi-Jiang , Yang Chao , Zhang Di
Published: June 2015

An Au(i)-catalyzed tandem reaction, involving a Meyer–Schuster rearrangement/1,2-migration/Paal–Knorr cyclization cascade has been successfully developed.
Iridium-catalyzed allyl–allyl cross-coupling of allylic carbonates with (E)-1,3-diarylpropenes
Authors: Yuan Qianjia , Yao Kun , Liu Delong , Zhang Wanbin
Published: June 2015

An efficient Ir-catalyzed allyl–allyl cross-coupling reaction of allylic carbonates with (E)-1,3-diarylpropenes was developed to form linear allylated products, 1,5-dienes, regioselectively in excellent yields and with high turnover numbers (up to 2000 S/Ir).
Accessing heavy allyl-analogous [(TerN)2E]− (E = Sb, Bi) ions and their reactivity towards ECl3
Authors: Hinz Alexander , Schulz Axel , Villinger Alexander
Published: June 2015

Highly reactive heavy heteroatom allyl analogues were obtained by reduction of 1,3-dichloro-cyclo-1,3-dipnicta-2,4-diazanes.
Chemically-derived CuO/In2O3-based nanocomposite for diode applications
Authors: Mohan Kumar G. , Ilanchezhiyan P. , Madhan Kumar A. , Shabi T. S. , Tamil Selvan S. , Suresh S. , Yuldashev Sh. U. , Kang T. W.
Published: June 2015

The potential of CuO-based nanocomposite synthesized through a facile surfactant-free wet chemical strategy has been demonstrated for photoelectronic applications.
The dynamics of adsorption and dissociation of N2 in a monolayer of iron on W(110)
Authors: Goikoetxea I. , Alducin M. , Díez Muiño R. , Juaristi J. I.
Published: June 2015

Does N2 adsorption increase on strained Fe monolayers?
Illustrating the formation of metal nanoparticles with a growth concept based on colloidal stability
Authors: Wuithschick M. , Witte S. , Kettemann F. , Rademann K. , Polte J.
Published: June 2015

The growth process of various colloidal metal nanoparticles is illustrated using a novel concept based on colloidal stability.
Influence of relative humidity on heterogeneous kinetics of NO2 on kaolin and hematite
Authors: Liu Yongchun , Han Chong , Ma Jinzhu , Bao Xiaolei , He Hong
Published: June 2015

In order to obtain reliable kinetic parameters, it is required to measure the reaction kinetics of important heterogeneous reactions at ambient relative humidity (RH).
On the formation of cyclopentadiene in the C3H5˙ + C2H2 reaction
Authors: Bouwman Jordy , Bodi Andras , Oomens Jos , Hemberger Patrick
Published: June 2015

Mass-selected threshold photoelectron spectroscopy has been employed to identify cyclopentadiene as the sole product of the allyl + acetylene reaction in a pyrolysis reactor tube.
Electron transfer kinetics on natural crystals of MoS2 and graphite
Authors: Velický Matěj , Bissett Mark A. , Toth Peter S. , Patten Hollie V. , Worrall Stephen D. , Rodgers Andrew N. J. , Hill Ernie W. , Kinloch Ian A. , Novoselov Konstantin S. , Georgiou Thanasis , Britnell Liam , Dryfe Robert A. W.
Published: June 2015

Electron transfer kinetics on MoS2 and graphite crystals are studied as a function of surface defectiveness, ageing, potential and illumination.
Morphology controllable nano-sheet polypyrrole–graphene composites for high-rate supercapacitor
Authors: Zhu Jianbo , Xu Youlong , Wang Jie , Wang Jingping , Bai Yang , Du Xianfeng
Published: June 2015

An excellent rate capability of PPy/RGO is achieved because its controllable special morphology provided fast charge/ion transfer and exchange.
Effects of dynamic vulcanization on the kinetics of isothermal crystallization in a miscible polymeric blend
Authors: Abolhasani Mohammad Mahdi
Published: June 2015

Is it possible to determine the state of phase separation using the free energy of folding parameter?
Oxidative addition of the C–I bond on aluminum nanoclusters
Authors: Sengupta Turbasu , Das Susanta , Pal Sourav
Published: June 2015

A comprehensive study on the reactivities and the reaction mechanism of aluminum nanoclusters towards oxidative addition of the C–I bond using DFT and BOMD simulation is carried out.
Thioether-directed acetoxylation of C(sp2)–H bonds of arenes by palladium catalysis
Authors: Wang Binjie , Lin Cong , Liu Yue , Fan Zili , Liu Zhanxiang , Zhang Yuhong
Published: June 2015

The palladium-catalyzed acetoxylation of aromatic C(sp2)–H bonds utilizing thioether as the directing group was developed.
The remarkable role of solvent in reaction mechanism studies by electrospray mass spectrometry
Authors: Wang Hao-Yang , Zhang Jun-Ting , Zhang Shu-Sheng , Guo Yin-Long
Published: June 2015

The solvent assistance technologies in detecting reactive intermediates in complicated reaction solutions using electrospray mass spectrometry were summarized and discussed.
Engineering ligands on the Au center: discovering broadly applicable gold catalysis with high turnover numbers
Authors: Inamdar Suleman M. , Patil Nitin T.
Published: June 2015

The research groups of Hammond/Xu and Zhang report the discovery of new ligands for gold catalysis.
High oxygen storage capacity and enhanced catalytic performance of NiO/NixCe1−xO2−δ nanorods: synergy between Ni-doping and 1D morphology
Authors: Romero-Núñez Araceli , Díaz Gabriela
Published: June 2015

NiO/Ni-doped ceria nanorods have been synthesized. Their unique structure combines specific composition and 1D morphology, which provide great improvements in their physical chemical properties.
A turn-on and colorimetric metal-free long lifetime fluorescent probe and its application for time-resolved luminescent detection and bioimaging of cysteine
Authors: Xiong Xiaoqing , Zheng Laijiu , Yan Jun , Ye Fang , Qian Yongfang , Song Fengling
Published: June 2015

An excellent turn-on and colorimetric fluorescent chemosensor DCF-MPYM-thiol for sensing Cys based on metal-free organic fluorophores has been synthesized.
Anticorrosive assay-guided isolation of active phytoconstituents from Anthemis pseudocotula extracts and a detailed study of their effects on the corrosion of mild steel in acidic media
Authors: Alkhathlan H. Z. , Khan M. , Abdullah M. M. S. , AlMayouf A. M. , Badjah-Hadj-Ahmed A. Yacine , AlOthman Z. A. , Mousa A. A.
Published: June 2015

In this study, anticorrosive properties of various extracts (methanolic, aqueous methanolic and water extracts) ofAnthemis pseudocotulafor mild steel in 1.0 M HCl media is screened for the first time.
Tumor specific delivery with redox-triggered mesoporous silica nanoparticles inducing neovascularization suppression and vascular normalization
Authors: Sun Lu , Liu Yu-Jie , Yang Zhen-Zhen , Qi Xian-Rong
Published: June 2015

Redox-responsive mesoporous silica nanoparticles with enlarged pores (denoted as MSN-siRNA/CrPEI) were designed by immobilizing polyethylenimine (PEI)viaintermediate linkers of disulfide bonds onto the MSNs as caps for redox-responsive intracellular gene delivery.
Phospholipid electrospun nanofibers: effect of solvents and co-axial processing on morphology and fiber diameter
Authors: Jørgensen Lars , Qvortrup Klaus , Chronakis Ioannis S.
Published: June 2015

Asolectin phospholipid nano-microfibers were prepared using electrospinning processing. The lowest average fiber diameter of 0.38 ± 0.14 μm was achieved.
Correction: Using a functional C84 monolayer to improve the mechanical properties and alter substrate deformation
Authors: Lee Wen-Jay , Ho Mon-Shu , Huang Chih-Pong , Chou Che-Fu , Tsai Jyun-Hwei , Su Wan-Sheng
Published: June 2015

Correction for ‘Using a functional C84 monolayer to improve the mechanical properties and alter substrate deformation’ by Wen-Jay Lee et al., RSC Adv., 2015, 5, 47498–47505.
An efficiently tuned d-orbital occupation of IrO2by doping with Cu for enhancing the oxygen evolution reaction activity
Authors: Sun Wei , Song Ya , Gong Xue-Qing , Cao Li-mei , Yang Ji
Published: June 2015

Tuning Ir d-orbital occupationviadoping Cu into the IrO2lattice to prepare a highly efficient oxygen evolution reaction catalyst, Cu0.3Ir0.7Oδ.
Decomposable double-walled hybrid nanorods: formation mechanism and their effect on flame retardancy of epoxy resin composites
Authors: Huang Y. W. , Song S. Q. , Yang Y. , Cao K. , Yang J. X. , Chang G. J.
Published: June 2015

Double-walled Al–P–Si hybrid decomposable nanorods, which have a silica coated aluminum phosphonate nanostructure, were in situ prepared by thorough but ordered reconstruction of montmorillonite.
Growth of 3D SnO2 nanosheets on carbon cloth as a binder-free electrode for supercapacitors
Authors: Zhang Yadi , Hu Zhongai , Liang Yarong , Yang Yuying , An Ning , Li Zhimin , Wu Hongying
Published: June 2015

Three-dimensional (3D) lamellar SnO2 is grown on a carbon cloth (CC) substrate (denoted as 3D lamellar SnO2/CC) through hydrothermal reactions and subsequent thermal treatments.
A strategy for breaking the MOF template to obtain small-sized and highly dispersive polyoxometalate clusters loaded on solid films
Authors: Li Jian-Sheng , Sang Xiao-Jing , Chen Wei-Lin , Zhang Lan-Cui , Zhu Zai-Ming , Li Yang-Guang , Su Zhong-Min , Wang En-Bo
Published: June 2015

Highly dispersed and small sized POM nanoclusters that were fabricated using MOF materials can result in a significant performance enhancement of QDSCs.
Cellulose nanofibril core–shell silica coatings and their conversion into thermally stable nanotube aerogels
Authors: Liu Dongming , Wu Qiong , Andersson Richard L. , Hedenqvist Mikael S. , Farris Stefano , Olsson Richard T.
Published: June 2015

Thermally stable, ultra-low density, silica-nanotube-based aerogels created via templating from cellulose nanofibrils without relying on energy intensive supercritical drying.
Aqueous processing of paper separators by filtration dewatering: towards Li-ion paper batteries
Authors: Zolin Lorenzo , Destro Matteo , Chaussy Didier , Penazzi Nerino , Gerbaldi Claudio , Beneventi Davide
Published: June 2015

Despite the high number of research articles regarding the development of new high performance electrolytes for Li-ion batteries, relatively little work has been carried out for the investigation of green, mechanically robust, safe and commercially applicable paper separators.
Ternary graphene quantum dot–polydopamine–Mn3O4nanoparticles for optical imaging guided photodynamic therapy and T1-weighted magnetic resonance imaging
Authors: Nafiujjaman Md , Nurunnabi Md , Kang Sung-hun , Reeck Gerald R. , Khan Haseeb A. , Lee Yong-kyu
Published: June 2015

Dual imaging guided therapeutic agents where the Mn3O4cores are combined with graphene quantum dot resulted in significant phototherapeutic effects, apparently by generating toxic reactive oxygen species.
Vertex Epidural Hematoma—A Rare Cause of Quadriparesis
Authors: Sharma Somnath , Chandra Anil , Singh Sunil Kumar , Srivastava Chhitij , Ojha Bal Krishna
Published: June 2015

Vertex epidural hematomas (VEHs) are rare and account for 1 to 8% of all epidural hematomas (EDHs). The clinical picture of VEH is variable and nonspecific, and presentation with quadriparesis is very rare. A 60-year-old man presented after head injury to emergency department with quadriparesis and unconsciousness. His Glasgow Coma Score was E1V1M5 and motor power in the right upper limb was 3/5. Power in the rest B/L lower limb and left upper limb was 0/5. Cervical spine was stabilized. CT head revealed large epidural hematoma present over the vertex with bilateral parietal contusion and skull fracture. CT cervical spine was normal. The patient was taken for emergency surgery and EDH evacuated. His Glasgow Coma Score improved to E4V5M6 over the next 2 days and power improved to 3/5 in all four limbs within 3 days and later on to 4+/5 by the time of discharge at 15 days. In the postoperative period, after the patient's clinical status stabilized, he underwent screening MRI of the spine, which was normal. In conclusion, VEHs should be considered as a possibility in patients of TBI with quadriparesis, especially when the spine is normal.
Scaling of extreme rainfall areas at a planetary scale
Authors: Devineni Naresh , Lall Upmanu , Xi Chen , Ward Philip
Published: June 2015

Event magnitude and area scaling relationships for rainfall over different regions of the world have been presented in the literature for relatively short durations and over relatively small areas. In this paper, we present the first ever results on a global analysis of the scaling characteristics of extreme rainfall areas for durations ranging from 1 to 30 days. Broken power law models are fit in each case. The past work has been focused largely on the time and space scales associated with local and regional convection. The work presented here suggests that power law scaling may also apply to planetary scale phenomenon, such as frontal and monsoonal systems, and their interaction with local moisture recycling. Such features may have persistence over large areas corresponding to extreme rain and regional flood events. As a result, they lead to considerable hazard exposure. A caveat is that methods used for empirical power law identification have difficulties with edge effects due to finite domains. This leads to problems with robust model identification and interpretability of the underlying relationships. We use recent algorithms that aim to address some of these issues in a principled way. Theoretical research that could explain why such results may emerge across the world, as analyzed for the first time in this paper, is needed.
Relativistic coupled-cluster calculations on XeF6: Delicate interplay between electron-correlation and basis-set effects
Authors: Cheng Lan , Gauss Jürgen , Stanton John F.
Published: June 2015

A systematic relativistic coupled-cluster study is reported on the harmonic vibrational frequencies of the Oh, C3v, and C2v conformers of XeF6, with scalar-relativistic effects efficiently treated using the spin-free exact two-component theory in its one-electron variant (SFX2C-1e). Atomic natural orbital type basis sets recontracted for the SFX2C-1e scheme have been shown to provide rapid basis-set convergence for the vibrational frequencies. SFX2C-1e as well as complementary pseudopotential based computations consistently predicts that both Oh and C3v structures are local minima on the potential energy surface, while the C2v structure is a transition state. Qualitative disagreement between the present results for the Oh structure and those from CCSD(T)-F12b calculations [Peterson et al., J. Phys. Chem. A 116, 9777 (2012)], which yielded a triply degenerate imaginary frequency for the Oh structure, is attributed here to the high sensitivity of the computed harmonic frequencies of the t1u bending modes to the basis-set effects of triples contributions.
Some examples related to the method of Lagrangian descriptors
Authors: Ruiz-Herrera Alfonso
Published: June 2015

We provide families of counter-examples, including Hamiltonian systems, to the method of Lagrangian descriptors developed by Mancho, Wiggins, and their co-workers. A detailed mathematical discussion on why that methodology fails together with some pathological phenomena are given as well.
Effect of the interface resistance in non-local Hanle measurements
Authors: Villamor Estitxu , Hueso Luis E. , Casanova Fèlix
Published: June 2015

We use lateral spin valves with varying interface resistance to measure non-local Hanle effect in order to extract the spin-diffusion length of the non-magnetic channel. A general expression that describes spin injection and transport, taking into account the influence of the interface resistance, is used to fit our results. Whereas the fitted spin-diffusion length value is in agreement with the one obtained from standard non-local measurements in the case of a finite interface resistance, in the case of transparent contacts a clear disagreement is observed. The use of a corrected expression, recently proposed to account for the anisotropy of the spin absorption at the ferromagnetic electrodes, still yields a deviation of the fitted spin-diffusion length which increases for shorter channel distances. This deviation shows how sensitive the non-local Hanle fittings are, evidencing the complexity of obtaining spin transport information from such type of measurements.
Entoptic perceptions of spiral waves and rare inward spirals
Authors: Pearce Ida
Published: June 2015

This report concerns Entoptic Rotating Spiral Waves as observed and documented by the author over a period of 46 years (1962–2008). The manifestations of these state-dependent, elusive rotating spiral entities were brief, emerging only during sleep-to-waking arousal epochs (in limbo). The images were seen only with closed lids in favorable ambient lighting—here, termed the umbral view. The clusters of rotating spiral entities emerge briefly to conscious view; their angular subtenses are estimated to be between 1° and 4°, and the rotations at ten-turns per second. Epochs of these activities commonly continued for about 20 s, with longevity of each visible entity up to 4 s. 90% of all observed entities were circular and outwardly levorotary; 5% were elliptical, appearing only as horizontal (prolate) entities. Overlapping units were rare, and were chiefly elliptical. Observations of twin spirals were also rare, seen in counter rotations, each twin inwardly rotating.
Self-propulsion of a counter-rotating cylinder pair in a viscous fluid
Authors: van Rees Wim M. , Novati Guido , Koumoutsakos Petros
Published: June 2015

We study a self-propelling pair of steadily counter-rotating cylinders in simulations of a two-dimensional viscous fluid. We find two strikingly, opposite directions for the motion of the pair that is characterized by its width and rotational Reynolds number. At low Reynolds numbers and large widths, the cylinder pair moves similarly to an inviscid point vortex pair, while at higher Reynolds numbers and smaller widths, the pair moves in the opposite direction through a jet-like propulsion mechanism. Increasing further the Reynolds number, or decreasing the width, gives rise to non-polarised motion governed by the shedding direction and frequency of the boundary-layer vorticity. We discuss the fundamental physical mechanisms for these two types of motion and the transitions in the corresponding phase diagram. We discuss the fluid dynamics of each regime based on streamline plots, tracer particles, and the vorticity field. The counter rotating cylinder pair serves as a prototype for self-propelled bodies and suggests possible engineering devices composed of simple components and tunable by the rotation and width of the cylinder pair.
Inertial and viscoelastic forces on rigid colloids in microfluidic channels
Authors: Howard Michael P. , Panagiotopoulos Athanassios Z. , Nikoubashman Arash
Published: June 2015

We perform hybrid molecular dynamics simulations to study the flow behavior of rigid colloids dispersed in a dilute polymer solution. The underlying Newtonian solvent and the ensuing hydrodynamic interactions are incorporated through multiparticle collision dynamics, while the constituent polymers are modeled as bead-spring chains, maintaining a description consistent with the colloidal nature of our system. We study the cross-stream migration of the solute particles in slit-like channels for various polymer lengths and colloid sizes and find a distinct focusing onto the channel center under specific solvent and flow conditions. To better understand this phenomenon, we systematically measure the effective forces exerted on the colloids. We find that the migration originates from a competition between viscoelastic forces from the polymer solution and hydrodynamically induced inertial forces. Our simulations reveal a significantly stronger fluctuation of the lateral colloid position than expected from thermal motion alone, which originates from the complex interplay between the colloid and polymer chains.
Dynamical mean-field theory and weakly non-linear analysis for the phase separation of active Brownian particles
Authors: Speck Thomas , Menzel Andreas M. , Bialké Julian , Löwen Hartmut
Published: June 2015

Recently, we have derived an effective Cahn-Hilliard equation for the phase separation dynamics of active Brownian particles by performing a weakly non-linear analysis of the effective hydrodynamic equations for density and polarization [Speck et al., Phys. Rev. Lett. 112, 218304 (2014)]. Here, we develop and explore this strategy in more detail and show explicitly how to get to such a large-scale, mean-field description starting from the microscopic dynamics. The effective free energy emerging from this approach has the form of a conventional Ginzburg-Landau function. On the coarsest scale, our results thus agree with the mapping of active phase separation onto that of passive fluids with attractive interactions through a global effective free energy (motility-induced phase transition). Particular attention is paid to the square-gradient term necessary for the phase separation kinetics. We finally discuss results from numerical simulations corroborating the analytical results.
Characterization of deep level defects and thermally stimulated depolarization phenomena in La-doped TlInS2 layered semiconductor
Authors: Seyidov MirHasan Yu. , Suleymanov Rauf A. , Mikailzade Faik A. , Kargın Elif Orhan , Odrinsky Andrei P.
Published: June 2015

Lanthanum-doped high quality TlInS2 (TlInS2:La) ferroelectric-semiconductor was characterized by photo-induced current transient spectroscopy (PICTS). Different impurity centers are resolved and identified. Analyses of the experimental data were performed in order to determine the characteristic parameters of the extrinsic and intrinsic defects. The energies and capturing cross section of deep traps were obtained by using the heating rate method. The observed changes in the Thermally Stimulated Depolarization Currents (TSDC) near the phase transition points in TlInS2:La ferroelectric-semiconductor are interpreted as a result of self-polarization of the crystal due to the internal electric field caused by charged defects. The TSDC spectra show the depolarization peaks, which are attributed to defects of dipolar origin. These peaks provide important information on the defect structure and localized energy states in TlInS2:La. Thermal treatments of TlInS2:La under an external electric field, which was applied at different temperatures, allowed us to identify a peak in TSDC which was originated from La-dopant. It was established that deep energy level trap BTE43, which are active at low temperature (T ≤ 156 K) and have activation energy 0.29 eV and the capture cross section 2.2 × 10−14 cm2, corresponds to the La dopant. According to the PICTS results, the deep level trap center B5 is activated in the temperature region of incommensurate (IC) phases of TlInS2:La, having the giant static dielectric constant due to the structural disorders. From the PICTS simulation results for B5, native deep level trap having an activation energy of 0.3 eV and the capture cross section of 1.8 × 10−16 cm2 were established. A substantial amount of residual space charges is trapped by the deep level localized energy states of B5 in IC-phase. While the external electric field is applied, permanent dipoles, which are originated from the charged B5 deep level defects, are aligned in the direction of the applied electric field and the equilibrium polarization can be reached in a relatively short time. When the polarization field is maintained, while cooling the temperature of sample to a sufficiently low degrees, the relaxation times of the aligned dipoles drastically increases. Practically, frozen internal electric field or electrets states remain inside the TlInS2:La when the applied bias field is switched off. The influence of deep level defects on TSDC spectra of TlInS2:La has been revealed for the first time.
Rotating disk electrode system for elevated pressures and temperatures
Authors: Fleige M. J. , Wiberg G. K. H. , Arenz M.
Published: June 2015

We describe the development and test of an elevated pressure and temperature rotating disk electrode (RDE) system that allows measurements under well-defined mass transport conditions. As demonstrated for the oxygen reduction reaction on polycrystalline platinum (Pt) in 0.5M H2SO4, the setup can easily be operated in a pressure range of 1–101 bar oxygen, and temperature of 140 °C. Under such conditions, diffusion limited current densities increase by almost two orders of magnitude as compared to conventional RDE setups allowing, for example, fuel cell catalyst studies under more realistic conditions. Levich plots demonstrate that the mass transport is indeed well-defined, i.e., at low electrode potentials, the measured current densities are fully diffusion controlled, while at higher potentials, a mixed kinetic-diffusion controlled regime is observed. Therefore, the setup opens up a new field for RDE investigations under temperature and current density conditions relevant for low and high temperature proton exchange membrane fuel cells.
Data collection strategies for time-resolved X-ray free-electron laser diffraction, and 2-color methods
Authors: Li Chufeng , Schmidt Kevin , Spence John C.
Published: June 2015

We compare three schemes for time-resolved X-ray diffraction from protein nanocrystals using an X-ray free-electron laser. We find expressions for the errors in structure factor measurement using the Monte Carlo pump-probe method of data analysis with a liquid jet, the fixed sample pump-probe (goniometer) method (both diffract-and-destroy, and below the safe damage dose), and a proposed two-color method. Here, an optical pump pulse arrives between X-ray pulses of slightly different energies which hit the same nanocrystal, using a weak first X-ray pulse which does not damage the sample. (Radiation damage is outrun in the other cases.) This two-color method, in which separated Bragg spots are impressed on the same detector readout, eliminates stochastic fluctuations in crystal size, shape, and orientation and is found to require two orders of magnitude fewer diffraction patterns than the currently used Monte Carlo liquid jet method, for 1% accuracy. Expressions are given for errors in structure factor measurement for the four approaches, and detailed simulations provided for cathepsin B and IC3 crystals. While the error is independent of the number of shots for the dose-limited goniometer method, it falls off inversely as the square root of the number of shots for the two-color and Monte Carlo methods, with a much smaller pre-factor for the two-color mode, when the first shot is below the damage threshold.
Interaction of jump-fan composite waves in a two-dimensional jet for van der Waals gases
Authors: Lai Geng
Published: June 2015

We consider a two-dimensional (2D) jet by van der Waals gas streaming in parallel supersonic flow out of a duct into the atmosphere. We assume that the pressure p0 of the oncoming uniform parallel flow is greater than the atmospheric pressure pA and belongs to (p1e,p2i). Then at the corners at exit the oncoming flow expands in two symmetric jump-fan (jf) composite waves to the atmospheric pressure. These two jf composite waves interact and emerge as simple waves from their zone of penetration. We present a mathematical analysis of the interaction of the jf composite waves. To construct the flow in the interaction region, we consider a discontinuous Goursat problem for the 2D isentropic irrotational steady Euler equations. The existence of global piecewise C1 solution to the discontinuous Goursat problem is obtained constructively.
A multiscale approach to model hydrogen bonding: The case of polyamide
Authors: Gowers Richard J. , Carbone Paola
Published: June 2015

We present a simple multiscale model for polymer chains in which it is possible to selectively remove degrees of freedom. The model integrates all-atom and coarse-grained potentials in a simple and systematic way and allows a fast sampling of the complex conformational energy surface typical of polymers whilst maintaining a realistic description of selected atomistic interactions. In particular, we show that it is possible to simultaneously reproduce the structure of highly directional non-bonded interactions such as hydrogen bonds and efficiently explore the large number of conformations accessible to the polymer chain. We apply the method to a melt of polyamide removing from the model only the degrees of freedom associated to the aliphatic segments and keeping at atomistic resolution the amide groups involved in the formation of the hydrogen bonds. The results show that the multiscale model produces structural properties that are comparable with the fully atomistic model despite being five times faster to simulate.
Buffer influence on magnetic dead layer, critical current, and thermal stability in magnetic tunnel junctions with perpendicular magnetic anisotropy
Authors: Frankowski Marek , Żywczak Antoni , Czapkiewicz Maciej , Ziętek Sławomir , Kanak Jarosław , Banasik Monika , Powroźnik Wiesław , Skowroński Witold , Chęciński Jakub , Wrona Jerzy , Głowiński Hubert , Dubowik Janusz , Ansermet Jean-Philippe , Stobiecki Tomasz
Published: June 2015

We present a detailed study of Ta/Ru-based buffers and their influence on features crucial from the point of view of applications of Magnetic Tunnel Junctions (MTJs) such as critical switching current and thermal stability. We study buffer/FeCoB/MgO/Ta/Ru and buffer/MgO/FeCoB/Ta/Ru layers, investigating the crystallographic texture, the roughness of the buffers, the magnetic domain pattern, the magnetic dead layer thickness, and the perpendicular magnetic anisotropy fields for each sample. Additionally, we examine the effect of the current induced magnetization switching for complete nanopillar MTJs with lateral dimensions of 270 × 180 nm. Buffer Ta 5/Ru 10/Ta 3 (thicknesses in nm), which has the thickest dead layer, exhibits a much larger thermal stability factor (63 compared to 32.5) while featuring a slightly lower critical current density value (1.25 MA/cm2 compared to 1.5 MA/cm2) than the buffer with the thinnest dead layer Ta 5/Ru 20/Ta 5. We can account for these results by considering the difference in damping which compensates for the difference in the switching barrier heights.
Optimization of L1 FePt/Fe45Co55 thin films for rare earth free permanent magnet applications
Authors: Giannopoulos G. , Reichel L. , Markou A. , Panagiotopoulos I. , Psycharis V. , Damm C. , Fähler S. , Khan Imran , Hong Jisang , Niarchos D.
Published: June 2015

The magnetic properties of magnetron sputtered bilayers consisting of Fe45Co55 ultrathin layers on top of L10 FePt films epitaxially grown on MgO substrates are studied in view of their possible application as rare earth free permanent magnets. It is found that FePt layers induce a tetragonal distortion to the Fe-Co layers which leads to increased anisotropy. This allows to take advantage of the Fe-Co high magnetic moment with less significant loss of the coercivity compared to a typical hard/soft exchange spring system. A maximum energy product approaching 50 MGOe is obtained for a FePt(7 ML)/FeCo/(5 ML) sample. The results are in accordance with first-principles computational methods, which predict that even higher energy products are possible for micromagnetically optimized microstructures.
Phase imaging microscopy for the diagnostics of plasma-cell interaction
Authors: Ohene Yolanda , Marinov Ilya , de Laulanié Lucie , Dupuy Corinne , Wattelier Benoit , Starikovskaia Svetlana
Published: June 2015

Phase images of biological specimens were obtained by the method of Quadriwave Lateral Shearing Interferometry (QWLSI). The QWLSI technique produces, at high resolution, phase images of the cells having been exposed to a plasma treatment and enables the quantitative analysis of the changes in the surface area of the cells over time. Morphological changes in the HTori normal thyroid cells were demonstrated using this method. There was a comparison of the cell behaviour between control cells, cells treated by plasma of a nanosecond dielectric barrier discharge, including cells pre-treated by catalase, and cells treated with an equivalent amount of H2O2. The major changes in the cell membrane morphology were observed at only 5 min after the plasma treatment. The primary role of reactive oxygen species (ROS) in this degradation is suggested. Deformation and condensation of the cell nucleus were observed 2–3 h after the treatment and are supposedly related to apoptosis induction. The coupling of the phase QWLSI with immunofluorescence imaging would give a deeper insight into the mechanisms of plasma induced cell death.
Communication: One size fits all: Equilibrating chemically different polymer liquids through universal long-wavelength description
Authors: Zhang Guojie , Stuehn Torsten , Daoulas Kostas Ch. , Kremer Kurt
Published: June 2015

Mesoscale behavior of polymers is frequently described by universal laws. This physical property motivates us to propose a new modeling concept, grouping polymers into classes with a common long-wavelength representation. In the same class, samples of different materials can be generated from this representation, encoded in a single library system. We focus on homopolymer melts, grouped according to the invariant degree of polymerization. They are described with a bead-spring model, varying chain stiffness and density to mimic chemical diversity. In a renormalization group-like fashion, library samples provide a universal blob-based description, hierarchically backmapped to create configurations of other class-members. Thus, large systems with experimentally relevant invariant degree of polymerizations (so far accessible only on very coarse-grained level) can be microscopically described. Equilibration is verified comparing conformations and melt structure with smaller scale conventional simulations.
Spin-scattering rates in metallic thin films measured by ferromagnetic resonance damping enhanced by spin-pumping
Authors: Boone C. T. , Shaw J. M. , Nembach H. T. , Silva T. J.
Published: June 2015

We determined the spin-transport properties of Pd and Pt thin films by measuring the increase in ferromagnetic resonance damping due to spin-pumping in ferromagnetic (FM)-nonferromagnetic metal (NM) multilayers with varying NM thicknesses. The increase in damping with NM thickness depends strongly on both the spin- and charge-transport properties of the NM, as modeled by diffusion equations that include both momentum- and spin-scattering parameters. We use the analytical solution to the spin-diffusion equations to obtain spin-diffusion lengths for Pt and Pd. By measuring the dependence of conductivity on NM thickness, we correlate the charge- and spin-transport parameters, and validate the applicability of various models for momentum-scattering and spin-scattering rates in these systems: constant, inverse-proportional (Dyakanov-Perel), and linear-proportional (Elliot-Yafet). We confirm previous reports that the spin-scattering time appears to be shorter than the momentum scattering time in Pt, and the Dyakanov-Perel-like model is the best fit to the data.
Memristive behavior in a junctionless flash memory cell
Authors: Orak Ikram , Ürel Mustafa , Bakan Gokhan , Dana Aykutlu
Published: June 2015

We report charge storage based memristive operation of a junctionless thin film flash memory cell when it is operated as a two terminal device by grounding the gate. Unlike memristors based on nanoionics, the presented device mode, which we refer to as the flashristor mode, potentially allows greater control over the memristive properties, allowing rational design. The mode is demonstrated using a depletion type n-channel ZnO transistor grown by atomic layer deposition (ALD), with HfO2 as the tunnel dielectric, Al2O3 as the control dielectric, and non-stoichiometric silicon nitride as the charge storage layer. The device exhibits the pinched hysteresis of a memristor and in the unoptimized device, Roff/Ron ratios of about 3 are presented with low operating voltages below 5 V. A simplified model predicts Roff/Ron ratios can be improved significantly by adjusting the native threshold voltage of the devices. The repeatability of the resistive switching is excellent and devices exhibit 106 s retention time, which can, in principle, be improved by engineering the gate stack and storage layer properties. The flashristor mode can find use in analog information processing applications, such as neuromorphic computing, where well-behaving and highly repeatable memristive properties are desirable.
Role of dielectric properties in terahertz field transmission
Authors: Seo Minah , Lee Joong Wook , Kim Hwi
Published: June 2015

We compare the field transmission characteristics of a freestanding perforated metal film (as a conductor) and a polymethylmethacrylate–graphite composite film (as an absorber) in the terahertz frequency range. The role of dielectric properties of the materials and the contribution of surface waves toward enhanced transmission with periodic and random hole arrays are discussed. Periodic subwavelength hole arrays in metal films do support enhanced terahertz field transmission whereas random arrays do not. In contrast, neither periodic nor random arrays of subwavelength holes punctured in dielectric absorbers support such transmission. Notably, even a dielectric absorber with large holes, which is sufficiently larger than subwavelength holes, can result in features in transmission due to the shape resonance, but the effect is very small.
An accurate magnetic field solution for medical electromagnetic tracking coils at close range
Authors: Schroeder Tobias
Published: June 2015

Electromagnetic tracking uses transmitter field models to determine position and orientation of an object. An important application of this technology is surgical navigation, where instruments are frequently tracked at short distances from the transmitter. At short distances, conventional and widely used dipole field models can lead to errors in tracked position and orientation. To increase tracking accuracy in this scenario, this work describes a novel transmitter field model and compares its performance against the dipole model. Demonstrated tracking accuracy improvements could have far-reaching benefits for medical navigation applications.
Abnormal magnetic ordering and ferromagnetism in perovskite ScMnO3 film
Authors: Wang F. , Zhang Y. Q. , Liu W. , Ning X. K. , Bai Y. , Dai Z. M. , Ma S. , Zhao X. G. , Li S. K. , Zhang Z. D.
Published: June 2015

Bulk multiferroic ScMnO3 is the stable hexagonal phase, and it is very difficult to prepare its perovskite orthorhombic phase even under high pressure. We fabricated the orthorhombic ScMnO3 thin film by pulsed laser deposition through suitable substrate LaAlO3 and found that nano-scale twin-like domains are naturally formed in the thin film. Magnetic properties of the orthorhombic ScMnO3 thin films show that, besides normal antiferromagnetic ordering at 47 K, an anomalous magnetic transition occurs at 27 K for 60 nm film and at 36 K for 150 nm film only along the c-axis, which is absent in the ab-plane. Moreover, the second magnetic transition for both films is suppressed when the applied field increases from 1 kOe to 10 kOe. In addition, the ferromagnetism shows up in both films at 10 K, and saturation magnetization increases dramatically in 60 nm film compared with 150 nm film. We propose that the second magnetic transition might be more of lattice strain effect and also related to magnetism-induced ferroelectric polarization in orthorhombic RMnO3 thin films and low-temperature ferromagnetic properties in our films originate from the nano-scale twin-like domain structure.