bluuebunny/crossref_metadata_2025 huggingface dataset:
Aggregation and insertion of melittin and its analogue MelP5 into lipid bilayers at different concentrations: effects on pore size, bilayer thickness and dynamics
Authors: Woo Sun Young , Lee Hwankyu
Published: February 2017

Melittin and its analogue MelP5 (five mutations T10A, R22A, K23A, R24Q, and Q26L of melittin) were simulated with lipid bilayers at different peptide/lipid molar ratios using all-atom and coarse-grained (CG) force fields.
Stabilization of carbocations CH3+, C2H5+, i-C3H7+, tert-Bu+, and cyclo-pentyl+in solid phases: experimental data versus calculations
Authors: Stoyanov Evgenii S. , Nizovtsev Anton S.
Published: February 2017

Hyperconjugation in C2H5+and other carbocations.
Monte Carlo simulation of magnetic domain structure and magnetic properties near the morphotropic phase boundary
Authors: Wei Songrui , Yang Sen , Wang Dong , Song Xiaoping , Ke Xiaoqin , Gao Yipeng , Liao Xiaoqi , Wang Yunzhi
Published: February 2017

The magnetization properties changing with the anisotropy energy barrier (a) and temperature (b) under a constant field.
Partitioning of caffeine in lipid bilayers reduces membrane fluidity and increases membrane thickness
Authors: Khondker Adree , Dhaliwal Alexander , Alsop Richard J. , Tang Jennifer , Backholm Matilda , Shi An-Chang , Rheinstädter Maikel C.
Published: February 2017

Caffeine partitions in lipid membranes in the head to tail interface and leads to a thickening and defluidification.
Dimer crystallization of chiral proteoids
Authors: Wang Po-Yuan , Mason Thomas G.
Published: February 2017

When slowly crowded while undergoing Brownian motion, hard proteomimetic colloids (“proteoids”) hierarchically self-assemble into microcrystals of enantiopure lock-and-key dimers.
Recent developments in the field of photoluminescent organically modified cyclosiloxanes
Authors: Cai Yuanjing , Samedov Kerim , West Robert
Published: February 2017

A brief overview of organically modified cyclosiloxanes with a special focus on their synthesis and photophysical properties is presented.
Recent advances in chiral imino-containing ligands for metal-catalyzed asymmetric transformations
Authors: Chen Xu , Lu Zhan
Published: February 2017

In this review, the recent applications of a variety of chiral imino-containing ligands classified by different types of metal-catalyzed asymmetric reactions are summarized. The progress made in this area would encourage us to design and synthesize more novel chiral imino-containing ligands, and explore their applications in metal-catalyzed asymmetric transformations.
Characterization of drug encapsulation and retention in archaea-inspired tetraether liposomes
Authors: Leriche Geoffray , Cifelli Jessica L. , Sibucao Kevin C. , Patterson Joseph P. , Koyanagi Takaoki , Gianneschi Nathan C. , Yang Jerry
Published: February 2017

Archaea-inspired lipids exhibit reduced membrane permeability and increased retention of hydrophilic drugs in liposomes.
Iron catalyzed efficient synthesis of poly-functional primary amines via the direct use of ammonia
Authors: Ma Chaoqun , Chen Jianghui , Xing Dong , Sheng Yuan , Hu Wenhao
Published: February 2017

An iron catalyzed three-component reaction of alkyl diazoesters, isatins and ammonia is reported.
Homologation of α-aryl amino acids through quinone-catalyzed decarboxylation/Mukaiyama–Mannich addition
Authors: Haugeberg Benjamin J. , Phan Johnny H. , Liu Xinyun , O'Connor Thomas J. , Clift Michael D.
Published: February 2017

A new method for amino acid homologation by way of formal C–C bond functionalization is reported.
Solvent-free, mechanochemical syntheses of bulk trihalide perovskites and their nanoparticles
Authors: Jana Atanu , Mittal Mona , Singla Aayushi , Sapra Sameer
Published: February 2017

For the first time, we have synthesized APbBr3 (A = Cs+/MA+/FA+, where MA+ = CH3NH3+ and FA+ = CH(NH2)2+) bulk as well as nanoparticles (NPs) by solid-state reactions at room temperature.
X-ray crystallographic structure of a teixobactin analogue reveals key interactions of the teixobactin pharmacophore
Authors: Yang H. , Du Bois D. R. , Ziller J. W. , Nowick J. S.
Published: February 2017

X-ray crystallography reveals key interactions in the pharmacophore of the antibiotic teixobactin.
Spectral evidence for multi-pathway contribution to the upconversion pathway in NaYF4:Yb3+,Er3+ phosphors
Authors: Cho Youngho , Song Si Won , Lim Soo Yeong , Kim Jae Hun , Park Chan Ryang , Kim Hyung Min
Published: February 2017

Although upconversion phosphors have been widely used in nanomedicine, laser engineering, bioimaging, and solar cell technology, the upconversion luminescence mechanism of the phosphors has been fiercely debated.
Calculations of current densities for neutral and doubly charged persubstituted benzenes using effective core potentials
Authors: Rauhalahti Markus , Taubert Stefan , Sundholm Dage , Liégeois Vincent
Published: February 2017

Magnetically induced current density of C6I62+using GIMIC method and effective core potentials.
Synthetic mimics of biotin/(strept)avidin
Authors: Liu Wenqi , Samanta Soumen K. , Smith Bradley D. , Isaacs Lyle
Published: February 2017

Biotin/(strept)avidin self-assembly can be mimicked using supramolecular pairs based on synthetic derivatives of cyclodextrins, cucurbiturils, and various organic cyclophanes.
Dielectrowetting manipulation for digital microfluidics: creating, transporting, splitting, and merging of droplets
Authors: Geng Hongyao , Feng Jian , Stabryla Lisa Marie , Cho Sung Kwon
Published: February 2017

Fundamental and critical unit operations (creating, transporting, splitting and merging of droplets) for digital (droplet-based) microfluidic circuits have been established using dielectrowetting.
Magnetic digital microfluidics – a review
Authors: Zhang Yi , Nguyen Nam-Trung
Published: February 2017

A magnetic digital microfluidic platform manipulates droplets on an open surface.
Correction: Fluorescent natural products as probes and tracers in biology
Authors: Duval Romain , Duplais Christophe
Published: February 2017

Correction for ‘Fluorescent natural products as probes and tracers in biology’ by Romain Duval et al., Nat. Prod. Rep., 2017, DOI: 10.1039/c6np00111d.
Protecting group free synthesis of glycosyl thiols from reducing sugars in water; application to the production of N-glycan glycoconjugates
Authors: Alexander S. R. , Lim D. , Amso Z. , Brimble M. A. , Fairbanks A. J.
Published: February 2017

Un-protected 2-acetamido terminated reducing sugars may be converted into the corresponding glycosyl thiols in water, and conjugated to peptides using the thiol–ene click reaction without recourse to any protecting groups.
Mg(OMe)2 promoted allylic isomerization of γ-hydroxy-α,β-alkenoic esters to synthesize γ-ketone esters
Authors: Lai Luhao , Li A-Ni , Zhou Jiawei , Guo Yarong , Lin Li , Chen Wei , Wang Rui
Published: February 2017

Herein we report a facile Mg(OMe)2 promoted allylic isomerization to afford γ-keto esters involving an in situ dienolate intermediate.
Broad scope gold(i)-catalysed polyenyne cyclisations for the formation of up to four carbon–carbon bonds
Authors: Rong Zhouting , Echavarren Antonio M.
Published: February 2017

The polycyclisation of polyeneynes catalyzed by gold(i) has been extended for the first time to the simultaneous formation of up to four carbon–carbon bonds, leading to steroid-like molecules with high stereoselectivity in a single step with low catalyst loadings.
Correction: PAMAM/5-fluorouracil drug conjugate for targeting E6 and E7 oncoproteins in cervical cancer: a combined experimental/in silico approach
Authors: Rengaraj Arunkumar , Subbiah Balaji , Haldorai Yuvaraj , Yesudhas Dhanusha , Yun Hyung Joong , Kwon Soonjo , Choi Sangdun , Han Young-Kyu , Kim Eung-Soo , Shenpagam N. Hema , Huh Yun Suk
Published: February 2017

Correction for ‘PAMAM/5-fluorouracil drug conjugate for targeting E6 and E7 oncoproteins in cervical cancer: a combined experimental/in silico approach’ by Arunkumar Rengaraj et al., RSC Adv., 2017, 7, 5046–5054.
Correction: Single-crystal TiO2 nanowires by seed assisted thermal oxidation of Ti foil: synthesis and photocatalytic properties
Authors: Arcadipane E. , Sanz R. , Amiard G. , Boninelli S. , Impellizzeri G. , Privitera V. , Bonkerud J. , Bhoodoo C. , Vines L. , Svensson B. G. , Romano L.
Published: February 2017

Correction for ‘Single-crystal TiO2 nanowires by seed assisted thermal oxidation of Ti foil: synthesis and photocatalytic properties’ by E. Arcadipane et al., RSC Adv., 2016, 6, 55490–55498.
Nanoscale hybrid systems based on carbon nanotubes for biological sensing and control
Authors: Cho Youngtak , Shin Narae , Kim Daesan , Park Jae Yeol , Hong Seunghun
Published: February 2017

This paper provides a concise review on the recent development of nanoscale hybrid systems based on carbon nanotubes (CNTs) for biological sensing and control. CNT-based hybrid systems have been intensively studied for versatile applications of biological interfaces such as sensing, cell therapy and tissue regeneration. Recent advances in nanobiotechnology not only enable the fabrication of highly sensitive biosensors at nanoscale but also allow the applications in the controls of cell growth and differentiation. This review describes the fabrication methods of such CNT-based hybrid systems and their applications in biosensing and cell controls.
VMP1-related autophagy induced by a fructose-rich diet in β-cells: its prevention by incretins
Authors: Maiztegui Bárbara , Boggio Verónica , Román Carolina L. , Flores Luis E. , Zotto Héctor Del , Ropolo Alejandro , Grasso Daniel , Vaccaro María I. , Gagliardino Juan J.
Published: February 2017

The aim of the present study was to demonstrate the role of autophagy and incretins in the fructose-induced alteration of β-cell mass and function. Normal Wistar rats were fed (3 weeks) with a commercial diet without (C) or with 10% fructose in drinking water (F) alone or plus sitagliptin (CS and FS) or exendin-4 (CE and FE). Serum levels of metabolic/endocrine parameters, β-cell mass, morphology/ultrastructure and apoptosis, vacuole membrane protein 1 (VMP1) expression and glucose-stimulated insulin secretion (GSIS) were studied. Complementary to this, islets isolated from normal rats were cultured (3 days) without (C) or with F and F + exendin-4 or chloroquine. Expression of autophagy-related proteins [VMP1 and microtubule-associated protein light chain 3 (LC3)], apoptotic/antiapoptotic markers (caspase-3 and Bcl-2), GSIS and insulin mRNA levels were measured. F rats developed impaired glucose tolerance (IGT) and a significant increase in plasma triacylglycerols, thiobarbituric acid-reactive substances, insulin levels, homoeostasis model assessment (HOMA) for insulin resistance (HOMA-IR) and β-cell function (HOMA-β) indices. A significant reduction in β-cell mass was associated with an increased apoptotic rate and morphological/ultrastructural changes indicative of autophagic activity. All these changes were prevented by either sitagliptin or exendin-4. In cultured islets, F significantly enhanced insulin mRNA and GSIS, decreased Bcl-2 mRNA levels and increased caspase-3 expression. Chloroquine reduced these changes, suggesting the participation of autophagy in this process. Indeed, F induced the increase of both VMP1 expression and LC3-II, suggesting that VMP1-related autophagy is activated in injured β-cells. Exendin-4 prevented islet-cell damage and autophagy development. VMP1-related autophagy is a reactive process against F-induced islet dysfunction, being prevented by exendin-4 treatment. This knowledge could help in the use of autophagy as a potential target for preventing progression from IGT to type 2 diabetes mellitus.
Air and Bone Conduction Frequency-specific Auditory Brainstem Response in Children with Agenesis of the External Auditory Canal
Authors: Sleifer Pricila , Didoné Dayane , Keppeler Ísis , Bueno Claudine , Riesgo Rudimar
Published: February 2017

Introduction The tone-evoked auditory brainstem responses (tone-ABR) enable the differential diagnosis in the evaluation of children until 12 months of age, including those with external and/or middle ear malformations. The use of auditory stimuli with frequency specificity by air and bone conduction allows characterization of hearing profile.

Objective The objective of our study was to compare the results obtained in tone-ABR by air and bone conduction in children until 12 months, with agenesis of the external auditory canal.

Method The study was cross-sectional, observational, individual, and contemporary. We conducted the research with tone-ABR by air and bone conduction in the frequencies of 500 Hz and 2000 Hz in 32 children, 23 boys, from one to 12 months old, with agenesis of the external auditory canal.

Results The tone-ABR thresholds were significantly elevated for air conduction in the frequencies of 500 Hz and 2000 Hz, while the thresholds of bone conduction had normal values in both ears. We found no statistically significant difference between genders and ears for most of the comparisons.

Conclusion The thresholds obtained by bone conduction did not alter the thresholds in children with conductive hearing loss. However, the conductive hearing loss alter all thresholds by air conduction. The tone-ABR by bone conduction is an important tool for assessing cochlear integrity in children with agenesis of the external auditory canal under 12 months.
Keratoplastiken im Kindes- und Jugendalter
Authors: Lang S. , Richter C. , Richter O. , Böhringer D. , Geerling G. , Reinhard T.
Published: February 2017

Hintergrund Die Voraussetzungen für das langfristige Überleben einer perforierenden Keratoplastik sind im Säuglings- und Kindesalter aufgrund immunologischer Besonderheiten, der eingeschränkten Untersuchbarkeit sowie reduzierter Compliance und Therapieadhärenz à priori ungünstig. Jedoch stellt eine Hornhautübertragung oftmals die einzige Möglichkeit zur Prävention einer Amblyopie dar und ist somit alternativlos. Wir untersuchten das Indikationsspektrum, das Transplantatüberleben und das Komplikationsspektrum in einem bizentrischen Register aller Keratoplastiken im Kindesalter.

Material und Methoden Aus den elektronischen Transplantatregistern der beiden Zentren wurden alle Patienten recherchiert, die zum Zeitpunkt der jeweils 1. Keratoplastik das 18. Lebensjahr noch nicht vollendet hatten. Aus den Krankenakten wurden die Indikation, etwaiges Transplantatversagen, die Sehschärfe, Verlust des Augapfels und weitere Komplikationen systematisch recherchiert.

Ergebnisse Es wurden insgesamt 104 Augen von 95 Patienten (54 % weiblich) identifiziert. Das Durchschnittsalter bei der Operation betrug im Median 14 Jahre (Quartile 8 und 16 Jahre). Die Nachbeobachtungszeit lag im Median bei 2,7 Jahren. Es zeigten sich folgende Indikationen: Keratokonus (39 %), perforierende Verletzung (18 %), nicht herpetische Hornhautnarben (12 %), herpetische Hornhautnarben (6 %), Sklerokornea (3 %), Verätzung (3 %) und die heterogene Gruppe der sonstigen Indikationen (19 %). Das nach Kaplan-Meier geschätzte klare Transplantatüberleben reichte zum Zeitpunkt der Durchschnittsnachbeobachtungszeit von 100 % (Keratokonus) bis 35 % (Sklerokornea). Ein Verlust des Augapfels war ausschließlich nach perforierender Verletzung (n = 2) zu verzeichnen. Nach 1 Jahr sind in der Kaplan-Meier-Schätzung alle Transplantate in der Gruppe der Säuglinge eingetrübt. In der Gruppe der Kleinkinder bis Jugendlichen sind 90 % der Transplantate zu diesem Zeitpunkt noch klar.

Schlussfolgerungen Die Prognose der Keratoplastik im Kindesalter hängt sowohl von der initialen Indikation und damit indirekt von der Grunderkrankung als auch vom Alter ab. Eine besonders schlechte Prognose zeigte die Gruppe der Säuglinge mit einem nur sehr kurzen Transplantatüberleben. Bei den Indikationen zeigte die Gruppe der Kinder mit Keratokonus die besten Ergebnisse. Als prognostisch ungünstig erwiesen sich Sklerokornea sowie perforierende Augenverletzungen.
Potenziale und Limitationen der Detektion von zirkulierenden Melanomzellen
Authors: Lüke J. , Grisanti S. , Tura A.
Published: February 2017

Die Bestimmung und Charakterisierung zirkulierender Melanomzellen ist ein nicht invasives und komplikationsarmes Verfahren mit dem Potenzial, einen choroidalen Nävus von einem choroidalen Melanom abzugrenzen und frühzeitig einer Therapie zuführen zu können. Zukünftig bietet es die Chance, das therapeutische Ansprechen zu überwachen und bei der Therapieauswahl zu helfen. Es besteht die Hoffnung, weitere Erkenntnisse hinsichtlich des Metastasierungsprozesses zu gewinnen und damit Ansatzpunkte für die Entwicklung zielgerichteter Therapien. In diesem Artikel werden die verschiedenen Techniken der Bestimmung zirkulierender Tumorzellen vorgestellt und ihr Potenzial bzw. Limitationen diskutiert.
Two-space, two-time similarity solution for decaying homogeneous turbulence
Authors: Byers Clayton P. , Hultmark Marcus , George William K.
Published: February 2017

A two-point, two-time similarity solution is derived for homogeneous decaying turbulence. This is the first known solution which includes the temporal decay at two-different times. It assumes that the turbulence is homogeneous in all three space dimensions, and finds that homogeneity holds across time. The solutions show that time is logarithmically “stretched” while the homogeneous spatial scales grow. This solution reduces to the two point, single time equation when the two times are set equal. The turbulence initially decays exponentially, then asymptotically as t−n where n≥1 and equality is possible only if the initial energy is infinite. The methodology should be applicable to other non-equilibrium homogeneous turbulent flows.
Squeeze-film flow between a curved impermeable bearing and a flat porous bed
Authors: Knox D. J. , Duffy B. R. , McKee S. , Wilson S. K.
Published: February 2017

Axisymmetric squeeze-film flow in the thin gap between a stationary flat thin porous bed and a curved impermeable bearing moving under a prescribed constant load is analysed. The unsteady Reynolds equation is formulated and solved for the fluid pressure. This solution is used to obtain the time for the minimum fluid layer thickness to reduce to a given value, and, in particular, the finite time for the bearing and the bed to come into contact. The effect of varying the shape of the bearing and the permeability of the layer is investigated, and, in particular, it is found that both the contact time and the fluid pressure behave qualitatively differently for beds with small and large permeabilities. In addition, the paths of fluid particles initially situated in both the fluid layer and the porous bed are calculated. In particular, it is shown that, unlike in the case of a flat bearing, for a curved bearing there are fluid particles, initially situated in the fluid layer, that flow from the fluid layer into the porous bed and then re-emerge into the fluid layer, and the region in which these fluid particles are initially situated is determined.
Lumley decomposition of turbulent boundary layer at high Reynolds numbers
Authors: Tutkun Murat , George William K.
Published: February 2017

The decomposition proposed by Lumley in 1966 is applied to a high Reynolds number turbulent boundary layer. The experimental database was created by a hot-wire rake of 143 probes in the Laboratoire de Mécanique de Lille wind tunnel. The Reynolds numbers based on momentum thickness (Reθ) are 9800 and 19 100. Three-dimensional decomposition is performed, namely, proper orthogonal decomposition (POD) in the inhomogeneous and bounded wall-normal direction, Fourier decomposition in the homogeneous spanwise direction, and Fourier decomposition in time. The first POD modes in both cases carry nearly 50% of turbulence kinetic energy when the energy is integrated over Fourier dimensions. The eigenspectra always peak near zero frequency and most of the large scale, energy carrying features are found at the low end of the spectra. The spanwise Fourier mode which has the largest amount of energy is the first spanwise mode and its symmetrical pair. Pre-multiplied eigenspectra have only one distinct peak and it matches the secondary peak observed in the log-layer of pre-multiplied velocity spectra. Energy carrying modes obtained from the POD scale with outer scaling parameters. Full or partial reconstruction of turbulent velocity signal based only on energetic modes or non-energetic modes revealed the behaviour of urms in distinct regions across the boundary layer. When urms is based on energetic reconstruction, there exists (a) an exponential decay from near wall to log-layer, (b) a constant layer through the log-layer, and (c) another exponential decay in the outer region. The non-energetic reconstruction reveals that urms has (a) an exponential decay from the near-wall to the end of log-layer and (b) a constant layer in the outer region. Scaling of urms using the outer parameters is best when both energetic and non-energetic profiles are combined.
Rapid jetting status inspection and accurate droplet volume measurement for a piezo drop-on-demand inkjet print head using a scanning mirror for display applications
Authors: Shin Dong-Youn , Kim Minsung
Published: February 2017

Despite the inherent fabrication simplicity of piezo drop-on-demand inkjet printing, the non-uniform deposition of colourants or electroluminescent organic materials leads to faulty display products, and hence, the importance of rapid jetting status inspection and accurate droplet volume measurement increases from a process perspective. In this work, various jetting status inspections and droplet volume measurement methods are reviewed by discussing their advantages and disadvantages, and then, the opportunities for the developed prototype with a scanning mirror are explored. This work demonstrates that jetting status inspection of 384 fictitious droplets can be performed within 17 s with maximum and minimum measurement accuracies of 0.2 ± 0.5 μm for the fictitious droplets of 50 μm in diameter and −1.2 ± 0.3 μm for the fictitious droplets of 30 μm in diameter, respectively. In addition to the new design of an inkjet monitoring instrument with a scanning mirror, two novel methods to accurately measure the droplet volume by amplifying a minute droplet volume difference and then converting to other physical properties are suggested and the droplet volume difference of ±0.3% is demonstrated to be discernible using numerical simulations, even with the low measurement accuracy of 1 μm. When the fact is considered that the conventional vision-based method with a CCD camera requires the optical measurement accuracy less than 25 nm to measure the volume of an in-flight droplet in the nominal diameter of 50 μm at the same volume measurement accuracy, the suggested method with the developed prototype offers a whole new opportunity to inkjet printing for display applications.
Bandwidth broadening for stripline circulator
Authors: Chao Hsien-Wen , Wu Shi-Yao , Chang Tsun-Hsu
Published: February 2017

This work provides a detailed analysis and simulation to demonstrate how to broaden the operating bandwidth of a circulator. A double-Y junction circulator is designed, and the shape of the central stripline is optimized with the knowledge of a modified equation. The equation predicts two resonant conditions. The overlapping of the two resonant conditions jointly constitutes the broad bandwidth. The bias magnetic field is simulated and then used in full electromagnetic-wave simulation. The designed circulator was fabricated in the S-band for communication purpose. The measured results agree very well with simulation. The overall operation range is from 1643 to 2027 MHz with the insertion loss less than 0.35 dB, reflection, and isolation better than 20 dB. The mechanism will be discussed.
Free surface effects on the statistical properties of a submerged rectangular jet
Authors: Tay Godwin F. K. , Mishra Anuvrat , Kuhn David C. S. , Tachie Mark F.
Published: February 2017

The results of an experimental investigation of turbulent rectangular jets offset from a free surface are presented. Two rectangular jets of aspect ratio 2 and 4 were examined and the results were compared to a square jet at the same offset height ratio of h/De ≈ 2.7, where De is the circle-equivalent diameter of the nozzle. A particle image velocimetry (PIV) was used to measure the mean flow and turbulent characteristics at a Reynolds number of 7900 and a Froude number of 1.29. The results indicate significant enhancements in the jet spreading rate and mean streamwise velocity decay rate for the larger aspect ratio nozzles. The results reveal that the jet-free surface interaction had a greater impact on the mean surface-normal velocity than the mean streamwise velocity. The values of the turbulence intensities, Reynolds shear stress and structure parameter were found to be nearly independent of the nozzle aspect ratio. Surface mean velocity and turbulence intensities were also measured to characterize the influence of the shear layer on the free surface. The results indicate a damping of the surface-normal turbulence intensities compared to the streamwise turbulence intensity. The influence of the free surface was felt as an enhancement in streamwise fluctuating velocity two-point correlation and a suppression of the surface-normal fluctuating velocity two-point correlation. The free surface also increased the structure inclination angle in the upper shear layer compared to that in the lower shear layer.
Wavefront sets and polarizations on supermanifolds
Authors: Dappiaggi Claudio , Gimperlein Heiko , Murro Simone , Schenkel Alexander
Published: February 2017

In this paper, we develop the foundation for microlocal analysis on supermanifolds. Making use of pseudodifferential operators on supermanifolds as introduced by Rempel and Schmitt, we define a suitable notion of super-wavefront set for superdistributions which generalizes Dencker’s polarization sets for vector-valued distributions to supergeometry. In particular, our super-wavefront sets detect polarization information of the singularities of superdistributions. We prove a refined pullback theorem for superdistributions along supermanifold morphisms, which as a special case establishes criteria when two superdistributions may be multiplied. As an application of our framework, we study the singularities of distributional solutions of a supersymmetric field theory.
Generalised hyperbolicity in spacetimes with Lipschitz regularity
Authors: Sanchez Sanchez Yafet , Vickers James A.
Published: February 2017

In this paper we obtain general conditions under which the wave equation is well-posed in spacetimes with metrics of Lipschitz regularity. In particular, the results can be applied to spacetimes where there is a loss of regularity on a hypersurface such as shell-crossing singularities, thin shells of matter, and surface layers. This provides a framework for regarding gravitational singularities not as obstructions to the world lines of point-particles, but rather as obstruction to the dynamics of test fields.
Protein simulation using coarse-grained two-bead multipole force field with polarizable water models
Authors: Li Min , Zhang John Z. H.
Published: February 2017

A recently developed two-bead multipole force field (TMFF) is employed in coarse-grained (CG) molecular dynamics (MD) simulation of proteins in combination with polarizable CG water models, the Martini polarizable water model, and modified big multipole water model. Significant improvement in simulated structures and dynamics of proteins is observed in terms of both the root-mean-square deviations (RMSDs) of the structures and residue root-mean-square fluctuations (RMSFs) from the native ones in the present simulation compared with the simulation result with Martini’s non-polarizable water model. Our result shows that TMFF simulation using CG water models gives much stable secondary structures of proteins without the need for adding extra interaction potentials to constrain the secondary structures. Our result also shows that by increasing the MD time step from 2 fs to 6 fs, the RMSD and RMSF results are still in excellent agreement with those from all-atom simulations. The current study demonstrated clearly that the application of TMFF together with a polarizable CG water model significantly improves the accuracy and efficiency for CG simulation of proteins.
Improved virtual orbitals in state specific multireference perturbation theory for prototypes of quasidegenerate electronic structure
Authors: Sinha Ray Suvonil , Ghosh Pradipta , Chaudhuri Rajat K. , Chattopadhyay Sudip
Published: February 2017

The state-specific multireference perturbation theory (SSMRPT) with an improved virtual orbital complete active space configuration interaction (IVO-CASCI) reference function [called as IVO-SSMRPT] is used to investigate the energy surface, geometrical parameters, molecular properties of spectroscopic interest for the systems/situations [such as BeH2, BeCH2, MgCH2, Si2H4, unimolecular dissociation of H2CO, and intramolecular reaction pathways of 1,3-butadiene] where the effect of quasidegeneracy cannot be neglected. The merit of using the IVO-CASCI rather than complete active space self-consistent field (CASSCF) is that it is free from iterations beyond those in the initial SCF calculation and the convergence difficulties that plague CASSCF calculations with increasing size of the CAS. While IVO-CASCI describes the non-dynamical correlation, the SSMRPT scheme is a good second-order perturbative approximation to account for the rest of the correlation energy. Our IVO-SSMRPT method is instrumental in avoiding intruder states in an size-extensive manner and allows the revision of the content of wave function in the model space. It can treat model as well as real systems with predictive accuracy, as is evident from the fairly nice accordance between our estimates, and high-level theoretical results. Our estimates also corroborate well with some experimental findings.
Role of local and nonlocal interactions in folding and misfolding of globular proteins
Authors: Kumar Adesh , Baruah Anupaul , Biswas Parbati
Published: February 2017

A Monte Carlo simulation based sequence design method is proposed to study the role of the local and the nonlocal interactions with varying secondary structure content in protein folding, misfolding and unfolding. A statistical potential is developed from the compilation of a data set of proteins, which accounts for the respective contribution of local and the nonlocal interactions. Sequences are designed through a combination of positive and negative design by a Monte Carlo simulation in the sequence space. The weights of the local and the nonlocal interactions are tuned appropriately to study the role of the local and the nonlocal interactions in the folding, unfolding and misfolding of the designed sequences. Results suggest that the nonlocal interactions are the primary determinant of protein folding while the local interactions may be required but not always necessary. The nonlocal interactions mainly guide the polypeptide chain to form compact structures but do not differentiate between the native-like conformations, while the local interactions stabilize the target conformation against the native-like competing conformations. The study concludes that the local interactions govern the fold-misfold transition, while the nonlocal interactions regulate the fold-unfold transition of proteins. However, for proteins with predominantly β-sheet content, the nonlocal interactions control both fold-misfold and fold-unfold transitions.
Modification of defects and potential fluctuations in slow-cooled and quenched Cu2ZnSnSe4 single crystals
Authors: Bishop Douglas M. , McCandless Brian , Gershon Talia , Lloyd Michael A. , Haight Richard , Birkmire Robert
Published: February 2017

Recent literature reports have shown the ability to manipulate Cu-Zn cation ordering for Cu2ZnSnSe4 (CZTSe) via low temperature treatments. Theoretical arguments suggest that one of the major roadblocks to higher VOC—significant band tailing—could be improved with increased cation order; however, few direct measurements have been reported and significant device improvements have not yet been realized. This report investigates electrical properties, defects, and devices from quenched and slow-cooled single crystals of CZTSe. The extent of disorder was characterized by Raman spectroscopy as well as x-ray diffraction, where the change in Cu-Zn order can be detected by a changing c/a ratio. Quenched samples show higher acceptor concentrations, lower hole mobilities, and a lower-energy photoluminescence (PL) peak than crystals cooled at slower rates, consistent with a reduction in the bandgap. In addition, samples quenched at the highest temperatures showed lower PL yield consistent with higher quantities of deep defects. Devices fabricated using slow-cooled CZTSe single crystals showed improved efficiencies, most notably with increased VOC; however, low temperature intensity-dependent photoluminescence measurements continue to indicate the existence of potential fluctuations. We discuss the possibility that potential fluctuations in slow-cooled samples may be related to the inability to achieve a long range order of the Cu-Zn sub-lattice resulting in local regions of high and low levels of cation order, and consequent local variations in the bandgap. The presence of significant potential fluctuations, even after the slow-cooling step, suggests the difficulty in eliminating band-tailing in this system, and thus, additional approaches may be needed for significant reduction of the VOC deficit.
Parallel tempering Monte Carlo combined with clustering Euclidean metric analysis to study the thermodynamic stability of Lennard-Jones nanoclusters
Authors: Cezar Henrique M. , Rondina Gustavo G. , Da Silva Juarez L. F.
Published: February 2017

A basic requirement for an atom-level understanding of nanoclusters is the knowledge of their atomic structure. This understanding is incomplete if it does not take into account temperature effects, which play a crucial role in phase transitions and changes in the overall stability of the particles. Finite size particles present intricate potential energy surfaces, and rigorous descriptions of temperature effects are best achieved by exploiting extended ensemble algorithms, such as the Parallel Tempering Monte Carlo (PTMC). In this study, we employed the PTMC algorithm, implemented from scratch, to sample configurations of LJn (n=38, 55, 98, 147) particles at a wide range of temperatures. The heat capacities and phase transitions obtained with our PTMC implementation are consistent with all the expected features for the LJ nanoclusters, e.g., solid to solid and solid to liquid. To identify the known phase transitions and assess the prevalence of various structural motifs available at different temperatures, we propose a combination of a Leader-like clustering algorithm based on a Euclidean metric with the PTMC sampling. This combined approach is further compared with the more computationally demanding bond order analysis, typically employed for this kind of problem. We show that the clustering technique yields the same results in most cases, with the advantage that it requires no previous knowledge of the parameters defining each geometry. Being simple to implement, we believe that this straightforward clustering approach is a valuable data analysis tool that can provide insights into the physics of finite size particles with few to thousand atoms at a relatively low cost.
The characteristics of Ta2O5 films deposited by radio frequency pure oxygen ion assisted deposition (RFOIAD) technology
Authors: Han Jinghua , Zhang Qiuhui , Fan Weixing , Feng Guoying , Li Yaguo , Wei Aixiang , Hu Ruifeng , Gu Qiongqiong
Published: February 2017

The characteristics of Ta2O5 films deposited by radio frequency pure oxygen ion assisted deposition (RFOIAD) technology were compared to a gas mixture of oxygen and argon (O2/Ar) ion beam assisted deposition experimentally and theoretically, inclusive of optical, electronic, and laser-induced damage resistance. The results showed that the RFOIAD could make removal of the pinholes and oxygen vacancies in the film and increase of the band gap, which resulted in the enhancement of refractive index, breakdown voltage, and the diminution of absorptivity as well as leakage current. The laser induced damage testing suggested that the damage induced damage threshold of the film deposited by RFOIAD could be increased, but the cracks appeared easily due to the concentration of thermal stress. While for the Ta2O5 film deposited using a sputtering gas of the mixtures of oxygen and argon, the porous characteristics were helpful to relief the thermal stress concentration, and the formation of cracks can be avoided.
Crossflow transition control by upstream flow deformation using plasma actuators
Authors: Dörr Philipp C. , Kloker Markus J.
Published: February 2017

Control of laminar-turbulent transition in a swept-wing-type boundary-layer flow, subject to primary crossflow instability, is investigated using direct numerical simulations. In our previous works, we explored a direct base-flow stabilization aimed at a spanwise homogenous flow manipulation or a direct crossflow-vortex manipulation by plasma actuators. In this paper, the technique of upstream flow deformation (UFD) is applied, needing by far the least energy input. The actuators, modeled by local volume forcing, are set to excite amplified steady crossflow vortex (CFV) control modes with a higher spanwise wavenumber than the most amplified modes. The resulting nonlinear control CFVs are spaced narrower than the naturally occurring vortices and are less unstable with respect to secondary instability. They generate a beneficial mean-flow distortion attenuating the primary crossflow instability, and thus a delay of the transition to turbulence. Unlike roughness elements for UFD, the employed dielectric barrier discharge plasma actuators allow to set the force direction: Forcing against the crossflow has a direct, fundamental stabilizing effect due to a reduction of the mean crossflow, whereas forcing in the crossflow direction locally invokes the opposite due to a local increase of the mean crossflow. The differences between these settings, also with respect to forcing in streamwise direction, are discussed in detail, and it is shown that a significant transition delay can be achieved indeed with both, however with a differing efficiency and robustness. Additionally, a comparison to a set-up with an excitation of the control modes by synthetic blowing and suction is performed to clarify the role of the direct effect on the base flow.
Surface acoustic wave unidirectional transducers for quantum applications
Authors: Ekström Maria K. , Aref Thomas , Runeson Johan , Björck Johan , Boström Isac , Delsing Per
Published: February 2017

The conversion efficiency of electric microwave signals into surface acoustic waves in different types of superconducting transducers is studied with the aim of quantum applications. We compare delay lines containing either conventional symmetric transducers (IDTs) or unidirectional transducers (UDTs) at 2.3 GHz and 10 mK. The UDT delay lines improve the insertion loss with 4.7 dB and a directivity of 22 dB is found for each UDT, indicating that 99.4% of the acoustic power goes in the desired direction. The power lost in the undesired direction accounts for more than 90% of the total loss in IDT delay lines, but only ∼3% of the total loss in the floating electrode unidirectional transducer delay lines.
Oxygen DX center in In0.17Al0.83N: Nonradiative recombination and persistent photoconductivity
Authors: Meli Rocco , Miceli Giacomo , Pasquarello Alfredo
Published: February 2017

Using a hybrid density-functional scheme, we address the O impurity substitutional to N (ON) in In0.17Al0.83N. Our modelling supports In clustering to account for the strong band-gap bowing observed in InxAl1−xN alloys. To study the ON defect in In0.17Al0.83N alloys, we therefore consider a model containing an In cluster and find that the most stable configuration shows four In nearest neighbors. We show that such a ON defect forms a DX center and gives rise to two defect levels at 0.70 and 0.41 eV below the conduction band edge, in good agreement with experiment. The calculated defect energetics entail a fast nonradiative recombination upon photoexcitation at room temperature and account for the observation of persistent photoconductivity at low temperature.
Tamper indicating gold nanocup plasmonic films
Authors: DeVetter Brent M. , Bernacki Bruce E. , Bennett Wendy D. , Schemer-Kohrn Alan , Alvine Kyle J.
Published: February 2017

The spectral signatures of nanoplasmonic films are both robust and tailorable with optical responses ranging from the visible to the near-infrared. We present the development of flexible, elastomeric nanoplasmonic films consisting of periodic arrays of gold nanocups as tamper indicating films. Gold nanocups have polarization-sensitive optical properties that may be manufactured into films that offer unique advantages for tamper indication. These flexible films can be made quickly and at low-cost using the commercially available monodisperse polystyrene nanospheres through self-assembly followed by plasma etching, metal deposition, and lift-off from a sacrificial substrate. The polarization- and angle-dependent optical spectroscopic measurements were performed to characterize the fabricated films. Using polarization-sensitive hyperspectral imaging, we demonstrate how these films can be applied to tamper indication and counterfeit resistance applications.
Self-forming oriented layer slip and macroscale super-low friction of graphene
Authors: Song Hui , Ji Li , Li Hongxuan , Wang Jinqing , Liu Xiaohong , Zhou Huidi , Chen Jianmin
Published: February 2017

Graphite lubrication is not effective in vacuum, and the failure mechanism is still under debate. Here, we show that graphene as two-dimensional (2D) “graphite paper” can overcome this shortcoming of graphite. Graphene exhibits stable super-low friction in a vacuum environment at the engineering scale because it can self-form a highly ordered lamellar structure on the sliding interface during the friction process owing to its unique 2D nano-effects. Experimental observation of the layer-slip phenomenon on the low-energy-state outside layers provides direct evidence to understand the lubrication mechanism of graphitic materials.
Dimensionless numbers in additive manufacturing
Authors: Mukherjee T. , Manvatkar V. , De A. , DebRoy T.
Published: February 2017

The effects of many process variables and alloy properties on the structure and properties of additively manufactured parts are examined using four dimensionless numbers. The structure and properties of components made from 316 Stainless steel, Ti-6Al-4V, and Inconel 718 powders for various dimensionless heat inputs, Peclet numbers, Marangoni numbers, and Fourier numbers are studied. Temperature fields, cooling rates, solidification parameters, lack of fusion defects, and thermal strains are examined using a well-tested three-dimensional transient heat transfer and fluid flow model. The results show that lack of fusion defects in the fabricated parts can be minimized by strengthening interlayer bonding using high values of dimensionless heat input. The formation of harmful intermetallics such as laves phases in Inconel 718 can be suppressed using low heat input that results in a small molten pool, a steep temperature gradient, and a fast cooling rate. Improved interlayer bonding can be achieved at high Marangoni numbers, which results in vigorous circulation of liquid metal, larger pool dimensions, and greater depth of penetration. A high Fourier number ensures rapid cooling, low thermal distortion, and a high ratio of temperature gradient to the solidification growth rate with a greater tendency of plane front solidification.
Enhancement of thermoelectric properties in benzene molecule junction by the magnetic flux
Authors: Li Haidong , Wang Yuan , kang Xiubao , Liu Shaohui , Li Ruixue
Published: February 2017

The thermoelectric properties through a benzene molecule with two metal leads are theoretically studied. The results reveal that the thermoelectric properties are strongly influenced by the magnetic flux. The reason for such a behavior is that the quantum interference caused by the magnetic field leads to the anti-resonance effect, which results in obvious thermoelectric effects. The value of ZT with a period of 1 for the magnetic flux and the magnitude of ZT may exceed 2 under some specific magnetic flux and onsite Coulomb interaction.
Shutterless ion mobility spectrometer with fast pulsed electron source
Authors: Bunert E. , Heptner A. , Reinecke T. , Kirk A. T. , Zimmermann S.
Published: February 2017

Ion mobility spectrometers (IMS) are devices for fast and very sensitive trace gas analysis. The measuring principle is based on an initial ionization process of the target analyte. Most IMS employ radioactive electron sources, such as 63Ni or 3H. These radioactive materials have the disadvantage of legal restrictions and the electron emission has a predetermined intensity and cannot be controlled or disabled. In this work, we replaced the 3H source of our IMS with 100 mm drift tube length with our nonradioactive electron source, which generates comparable spectra to the 3H source. An advantage of our emission current controlled nonradioactive electron source is that it can operate in a fast pulsed mode with high electron intensities. By optimizing the geometric parameters and developing fast control electronics, we can achieve very short electron emission pulses for ionization with high intensities and an adjustable pulse width of down to a few nanoseconds. This results in small ion packets at simultaneously high ion densities, which are subsequently separated in the drift tube. Normally, the required small ion packet is generated by a complex ion shutter mechanism. By omitting the additional reaction chamber, the ion packet can be generated directly at the beginning of the drift tube by our pulsed nonradioactive electron source with only slight reduction in resolving power. Thus, the complex and costly shutter mechanism and its electronics can also be omitted, which leads to a simple low-cost IMS-system with a pulsed nonradioactive electron source and a resolving power of 90.
Vacuum ultraviolet radiation effects on two-dimensional MoS2 field-effect transistors
Authors: McMorrow Julian J. , Cress Cory D. , Arnold Heather N. , Sangwan Vinod K. , Jariwala Deep , Schmucker Scott W. , Marks Tobin J. , Hersam Mark C.
Published: February 2017

Atomically thin MoS2 has generated intense interest for emerging electronics applications. Its two-dimensional nature and potential for low-power electronics are particularly appealing for space-bound electronics, motivating the need for a fundamental understanding of MoS2 electronic device response to the space radiation environment. In this letter, we quantify the response of MoS2 field-effect transistors (FETs) to vacuum ultraviolet (VUV) total ionizing dose radiation. Single-layer (SL) and multilayer (ML) MoS2 FETs are compared to identify differences that arise from thickness and band structure variations. The measured evolution of the FET transport properties is leveraged to identify the nature of VUV-induced trapped charge, isolating the effects of the interface and bulk oxide dielectric. In both the SL and ML cases, oxide trapped holes compete with interface trapped electrons, exhibiting an overall shift toward negative gate bias. Raman spectroscopy shows no variation in the MoS2 signatures as a result of VUV exposure, eliminating significant crystalline damage or oxidation as possible radiation degradation mechanisms. Overall, this work presents avenues for achieving radiation-hard MoS2 devices through dielectric engineering that reduces oxide and interface trapped charge.