bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations of interplanetary dust by the Juno magnetometer investigation
Authors: Benn M. , Jorgensen J. L. , Denver T. , Brauer P. , Jorgensen P. S. , Andersen A. C. , Connerney J. E. P. , Oliversen R. , Bolton S. J. , Levin S.
Published: May 2017

One of the Juno magnetometer investigation's star cameras was configured to search for unidentified objects during Juno's transit en route to Jupiter. This camera detects and registers luminous objects to magnitude 8. Objects persisting in more than five consecutive images and moving with an apparent angular rate of between 2 and 18,000 arcsec/s were recorded. Among the objects detected were a small group of objects tracked briefly in close proximity to the spacecraft. The trajectory of these objects demonstrates that they originated on the Juno spacecraft, evidently excavated by micrometeoroid impacts on the solar arrays. The majority of detections occurred just prior to and shortly after Juno's transit of the asteroid belt. This rather novel detection technique utilizes the Juno spacecraft's prodigious 60 m2 of solar array as a dust detector and provides valuable information on the distribution and motion of interplanetary (>μm sized) dust.
Juno‐UVS approach observations of Jupiter's auroras
Authors: Gladstone G. R. , Versteeg M. H. , Greathouse T. K. , Hue V. , Davis M. W. , Gérard J.‐C. , Grodent D. C. , Bonfond B. , Nichols J. D. , Wilson R. J. , Hospodarsky G. B. , Bolton S. J. , Levin S. M. , Connerney J. E. P. , Adriani A. , Kurth W. S. , Mauk B. H. , Valek P. , McComas D. J. , Orton G. S. , Bagenal F.
Published: May 2017

Juno ultraviolet spectrograph (UVS) observations of Jupiter's aurora obtained during approach are presented. Prior to the bow shock crossing on 24 June 2016, the Juno approach provided a rare opportunity to correlate local solar wind conditions with Jovian auroral emissions. Some of Jupiter's auroral emissions are expected to be controlled or modified by local solar wind conditions. Here we compare synoptic Juno‐UVS observations of Jupiter's auroral emissions, acquired during 3–29 June 2016, with in situ solar wind observations, and related Jupiter observations from Earth. Four large auroral brightening events are evident in the synoptic data, in which the total emitted auroral power increases by a factor of 3–4 for a few hours. Only one of these brightening events correlates well with large transient increases in solar wind ram pressure. The brightening events which are not associated with the solar wind generally have a risetime of ~2 h and a decay time of ~5 h.
Jupiter's North Equatorial Belt expansion and thermal wave activity ahead of Juno's arrival
Authors: Fletcher L. N. , Orton G. S. , Sinclair J. A. , Donnelly P. , Melin H. , Rogers J. H. , Greathouse T. K. , Kasaba Y. , Fujiyoshi T. , Sato T. M. , Fernandes J. , Irwin P. G. J. , Giles R. S. , Simon A. A. , Wong M. H. , Vedovato M.
Published: May 2017

The dark colors of Jupiter's North Equatorial Belt (NEB, 7–17°N) appeared to expand northward into the neighboring zone in 2015, consistent with a 3–5 year cycle. Inversions of thermal‐IR imaging from the Very Large Telescope revealed a moderate warming and reduction of aerosol opacity at the cloud tops at 17–20°N, suggesting subsidence and drying in the expanded sector. Two new thermal waves were identified during this period: (i) an upper tropospheric thermal wave (wave number 16–17, amplitude 2.5 K at 170 mbar) in the mid‐NEB that was anticorrelated with haze reflectivity; and (ii) a stratospheric wave (wave number 13–14, amplitude 7.3 K at 5 mbar) at 20–30°N. Both were quasi‐stationary, confined to regions of eastward zonal flow, and are morphologically similar to waves observed during previous expansion events.
Jupiter cloud morphology and zonal winds from ground‐based observations before and during Juno's first perijove
Authors: Hueso R. , Sánchez‐Lavega A. , Iñurrigarro P. , Rojas J. F. , Pérez‐Hoyos S. , Mendikoa I. , Gómez‐Forrellad J. M. , Go C. , Peach D. , Colas F. , Vedovato M.
Published: May 2017

We analyze Jupiter observations between December 2015 and August 2016 in the 0.38–1.7 μm wavelength range from the PlanetCam instrument at the 2.2 m telescope at Calar Alto Observatory and in the optical range by amateur observers contributing to the Planetary Virtual Observatory Laboratory. Over this time Jupiter was in a quiescent state without notable disturbances. Analysis of ground‐based images and Hubble Space Telescope observations in February 2016 allowed the retrieval of mean zonal winds from −74.5° to +73.2°. These winds did not change over 2016 or when compared with winds from previous years with the sole exception of intense zonal winds at the North Temperate Belt. We also present results concerning the major wave systems in the North Equatorial Belt and in the upper polar hazes visible in methane absorption bands, a description of the planet's overall cloud morphology and observations of Jupiter hours before Juno's orbit insertion.
The effect of differential rotation on Jupiter's low‐degree even gravity moments
Authors: Kaspi Y. , Guillot T. , Galanti E. , Miguel Y. , Helled R. , Hubbard W. B. , Militzer B. , Wahl S. M. , Levin S. , Connerney J. E. P. , Bolton S. J.
Published: May 2017

The close‐by orbits of the ongoing Juno mission allow measuring with unprecedented accuracy Jupiter's low‐degree even gravity moments J2, J4, J6, and J8. These can be used to better determine Jupiter's internal density profile and constrain its core mass. Yet the largest unknown on these gravity moments comes from the effect of differential rotation, which gives a degree of freedom unaccounted for by internal structure models. Here considering a wide range of possible internal flow structures and dynamical considerations, we provide upper bounds to the effect of dynamics (differential rotation) on the low‐degree gravity moments. In light of the recent Juno gravity measurements and their small uncertainties, this allows differentiating between the various models suggested for Jupiter's internal structure.
A heavy ion and proton radiation belt inside of Jupiter's rings
Authors: Kollmann P. , Paranicas C. , Clark G. , Mauk B. H. , Haggerty D. K. , Rymer A. M. , Santos‐Costa D. , Connerney J. E. P. , Allegrini F. , Valek P. , Kurth W. S. , Gladstone G. R. , Levin S. , Bolton S.
Published: May 2017

Energetic charged particle measurements by the Jupiter Energetic Particle Detector Instrument (JEDI) on board Juno have revealed a radiation belt of hundreds of keV ions up to the atomic mass of sulfur, located between Jupiter's rings and atmosphere. Proton energy spectra display an unusual intensity increase above 300 keV. We suggest that this is because charge exchange in Jupiter's neutral environment does not efficiently remove ions at such high energies. Since this innermost belt includes heavy ions, it cannot be exclusively supplied by cosmic ray albedo neutron decay, which is an important source at Earth and Saturn but only supplies protons and electrons. We find indications that the stripping of energetic neutral atoms in Jupiter's high atmosphere might be the ion source. Since the stripped off electrons are of low energy, this hypothesis is consistent with observations of the ratio of energetic electrons to ions being much less than 1.
Cycles of activity in the Jovian atmosphere
Authors: Fletcher L. N.
Published: May 2017

Jupiter's banded appearance may appear unchanging to the casual observer, but closer inspection reveals a dynamic, ever‐changing system of belts and zones with distinct cycles of activity. Identification of these long‐term cycles requires access to data sets spanning multiple Jovian years, but explaining them requires multispectral characterization of the thermal, chemical, and aerosol changes associated with visible color variations. The Earth‐based support campaign for Juno's exploration of Jupiter has already characterized two upheaval events in the equatorial and temperate belts that are part of long‐term Jovian cycles, whose underlying sources could be revealed by Juno's exploration of Jupiter's deep atmosphere.
A close‐up view of Jupiter's magnetic field from Juno: New insights into the planet's deep interior
Authors: Jones Chris A. , Holme Richard
Published: May 2017

The first results from the Juno mission magnetometer have recently become available. Juno provides us with the closest view of any planetary dynamo, flying to within 1.25 of the radius of the dynamo region, whereas for the Earth, we cannot get closer than 1.83 of the core‐mantle boundary radius. We compare the Juno results with those from first principles dynamo simulations of Jupiter's magnetic field. Intense flux patches at Jupiter's surface are found in both the data and the simulations, though the simulations have them mainly at slightly higher latitudes than the observations. We consider the prospects for determining more accurately the location of the top of the metallic hydrogen region and the implications of possible weak flux patches at the poles.
The soil moisture velocity equation
Authors: Ogden Fred L. , Allen Myron B. , Lai Wencong , Zhu Jianting , Seo Mookwon , Douglas Craig C. , Talbot Cary A.
Published: May 2017

Numerical solution of the one‐dimensional Richards' equation is the recommended method for coupling groundwater to the atmosphere through the vadose zone in hyperresolution Earth system models, but requires fine spatial discretization, is computationally expensive, and may not converge due to mathematical degeneracy or when sharp wetting fronts occur. We transformed the one‐dimensional Richards' equation into a new equation that describes the velocity of moisture content values in an unsaturated soil under the actions of capillarity and gravity. We call this new equation the Soil Moisture Velocity Equation (SMVE). The SMVE consists of two terms: an advection‐like term that accounts for gravity and the integrated capillary drive of the wetting front, and a diffusion‐like term that describes the flux due to the shape of the wetting front capillarity profile divided by the vertical gradient of the capillary pressure head. The SMVE advection‐like term can be converted to a relatively easy to solve ordinary differential equation (ODE) using the method of lines and solved using a finite moisture‐content discretization. Comparing against analytical solutions of Richards' equation shows that the SMVE advection‐like term is >99% accurate for calculating infiltration fluxes neglecting the diffusion‐like term. The ODE solution of the SMVE advection‐like term is accurate, computationally efficient and reliable for calculating one‐dimensional vadose zone fluxes in Earth system and large‐scale coupled models of land‐atmosphere interaction. It is also well suited for use in inverse problems such as when repeat remote sensing observations are used to infer soil hydraulic properties or soil moisture.
Trade‐off between cost and accuracy in large‐scale surface water dynamic modeling
Authors: Getirana Augusto , Peters‐Lidard Christa , Rodell Matthew , Bates Paul D.
Published: May 2017

Recent efforts have led to the development of the local inertia formulation (INER) for an accurate but still cost‐efficient representation of surface water dynamics, compared to the widely used kinematic wave equation (KINE). In this study, both formulations are evaluated over the Amazon basin in terms of computational costs and accuracy in simulating streamflows and water levels through synthetic experiments and comparisons against ground‐based observations. Varying time steps are considered as part of the evaluation and INER at 60 s time step is adopted as the reference for synthetic experiments. Five hybrid (HYBR) realizations are performed based on maps representing the spatial distribution of the two formulations that physically represent river reach flow dynamics within the domain. Maps have fractions of KINE varying from 35.6 to 82.8%. KINE runs show clear deterioration along the Amazon river and main tributaries, with maximum RMSE values for streamflow and water level reaching 7827 m3 s−1 and 1379 cm near the basin's outlet. However, KINE is at least 25% more efficient than INER with low model sensitivity to longer time steps. A significant improvement is achieved with HYBR, resulting in maximum RMSE values of 3.9–292 m3 s−1 for streamflows and 1.1–28.5 cm for water levels, and cost reduction of 6–16%, depending on the map used. Optimal results using HYBR are obtained when the local inertia formulation is used in about one third of the Amazon basin, reducing computational costs in simulations while preserving accuracy. However, that threshold may vary when applied to different regions, according to their hydrodynamics and geomorphological characteristics.
Analytical estimation show low depth‐independent water loss due to vapor flux from deep aquifers
Authors: Selker John S.
Published: May 2017

Recent articles have provided estimates of evaporative flux from water tables in deserts that span 5 orders of magnitude. In this paper, we present an analytical calculation that indicates aquifer vapor flux to be limited to 0.01 mm/yr for sites where there is negligible recharge and the water table is well over 20 m below the surface. This value arises from the geothermal gradient, and therefore, is nearly independent of the actual depth of the aquifer. The value is in agreement with several numerical studies, but is 500 times lower than recently reported experimental values, and 100 times larger than an earlier analytical estimate.
Redox modulation of thimet oligopeptidase activity by hydrogen peroxide
Authors: Icimoto Marcelo Y. , Ferreira Juliana C. , Yokomizo César H. , Bim Larissa V. , Marem Alyne , Gilio Joyce M. , Oliveira Vitor , Nantes Iseli L.
Published: May 2017

Thimet oligopeptidase (EC 3.4.24.15,TOP) is a cytosolic mammalian zinc protease that can process a diversity of bioactive peptides.TOPhas been pointed out as one of the main postproteasomal enzymes that process peptide antigens in theMHCclass I presentation route. In the present study, we describe a fine regulation ofTOPactivity by hydrogen peroxide (H2O2). Cells from a human embryonic kidney cell line (HEK293) underwent an ischemia/reoxygenation‐like condition known to increase H2O2production. Immediately after reoxygenation,HEK293 cells exhibited a 32% increase inTOPactivity, but noTOPactivity was observed 2 h after reoxygenation. In another model, recombinant ratTOP(rTOP) was challenged by H2O2produced by rat liver mitoplasts (RLMt) alone, and in combination with antimycin A, succinate, and antimycin A plus succinate. In these conditions,rTOPactivity increased 17, 30, 32 and 38%, respectively. Determination of H2O2concentration generated in reoxygenated cells and mitoplasts suggested a possible modulation ofrTOPactivity dependent on the concentration of H2O2. The measure of purerTOPactivity as a function of H2O2concentration corroborated this hypothesis. The data fitted to an asymmetrical bell‐shaped curve in which the optimal activating H2O2concentration was 1.2nM, and the maximal inhibition (75% about the control) was 1 μm. Contrary to the oxidation produced by aging associated with enzyme oligomerization and inhibition, H2O2oxidation produced sulfenic acid and maintainedrTOPin the monomeric form. Consistent with the involvement ofrTOPin a signaling redox cascade, the H2O2‐oxidizedrTOPreacted with dimeric thioredoxin‐1 (TRx‐1) and remained covalently bound to one subunit of TRx‐1.
Activation Energy and High Temperature Oxidation Behavior of Multi‐Principal Element Alloy
Authors: Grewal Harpreet Singh , Sanjiv Ramachandran Murali , Arora Harpreet Singh , Kumar Ram , Ayyagari Aditya , Mukherjee Sundeep , Singh Harpreet
Published: May 2017

Activation energy and diffusion kinetics are important in modulating the high temperature oxidation behavior of metals. Recently developed multi‐principal element alloys, also called high entropy alloys (HEAs), are promising candidate material for high temperature applications. However, the activation energies and diffusion kinetics of HEAs have been limitedly explored. We investigate the diffusional activation energy for oxidation of Al0.1CoCrFeNi HEA. Compared to conventional steels and Ni‐based super alloys, the HEA showed a significantly higher diffusion activation energy. This behavior is explained based on low potential energy of the lattice and interstitial sites which effectively trap the atoms, limiting their diffusion. The atomic mean jump frequency for interstitial diffusion of oxygen in the HEA is four‐orders of magnitude lower than T22 and T91 steels and seven‐orders of magnitude lower compared to pure iron. Al0.1CoCrFeNi HEA showed the lowest oxidation rate compared to conventionally used steels, super‐alloys, and coatings.
Effect of Crucible Material for Ingot Casting on Detrimental Non‐Metallic Inclusions and the Resulting Mechanical Properties of 18CrNiMo7‐6 Steel
Authors: Henschel Sebastian , Gleinig Johannes , Lippmann Tim , Dudczig Steffen , Aneziris Christos G. , Biermann Horst , Krüger Lutz , Weidner Anja
Published: May 2017

The steel 18CrNiMo7‐6 (AISI 4317) is treated in three different crucibles based on carbon‐bonded alumina. Non‐metallic inclusions in the steel are characterized by means of optical microscopy and scanning electron microscopy. Strength, ductility, and dynamic fracture toughness of the steel are evaluated at different temperatures. Furthermore, fatigue lifetimes in the very high cycle regime are determined. The treatment in a carbon‐bonded alumina (A–C) crucible resulted in a relatively high inclusion content involving a high number of duplex inclusions consisting of MnS and Si–Al–O. In contrast, less but large pure MnS inclusions are observed when the steel is treated in carbon‐bonded alumina‐zirconia‐titania crucibles – with or without a coating of carbon nanotubes (AZT–C–n and AZT–C). The steel treated in the A–C crucible exhibits the highest strength and fatigue lifetime, but the lowest energy dissipation. The relatively low inclusion content in the AZT–C treated steel results in high energy dissipation during tensile deformation. However, large MnS inclusions in the AZT–C and AZT–C–n treated steels act as crack initiation sites and reduce the fatigue lifetime. The dynamic fracture toughness is not affected by the different melt treatments. This result is explained by cell‐like structures within the material that are characterized by a lower strength and an increased concentration of MnS inclusions.
Oxygen Vacancies Evoked Blue TiO2(B) Nanobelts with Efficiency Enhancement in Sodium Storage Behaviors
Authors: Zhang Yan , Ding Zhiying , Foster Christopher W. , Banks Craig E. , Qiu Xiaoqing , Ji Xiaobo
Published: May 2017

Oxygen vacancies (OVs) dominate the physical and chemical properties of metal oxides, which play crucial roles in the various fields of applications. Density functional theory calculations show the introduction of OVs in TiO2(B) gives rise to better electrical conductivity and lower energy barrier of sodiation. Here, OVs evoked blue TiO2(B) (termed as B‐TiO2(B)) nanobelts are successfully designed upon the basis of electronically coupled conductive polymers to TiO2, which is confirmed by electron paramagnetic resonance and X‐ray photoelectron spectroscopy. The superiorities of OVs with the aid of carbon encapsulation lead to higher capacity (210.5 mAh g−1 (B‐TiO2(B)) vs 102.7 mAh g−1 (W‐TiO2(B)) at 0.5 C) and remarkable long‐term cyclability (the retention of 94.4% at a high rate of 10 C after 5000 times). In situ X‐ray diffractometer analysis spectra also confirm that an enlarged interlayer spacing stimulated by OVs is beneficial to accommodate insertion and removal of sodium ions to accelerate storage kinetics and preserve its original crystal structure. The work highlights that injecting OVs into metal oxides along with carbon coating is an effective strategy for improving capacity and cyclability performances in other metal oxide based electrochemical energy systems.
Supramolecular‐Assembled Nanoporous Film with Switchable Metal Salts for a Triboelectric Nanogenerator
Authors: Park Chanho , Song Giyoung , Cho Suk Man , Chung Jihoon , Lee Yujeong , Kim Eui Hyuk , Kim Minjoo , Lee Sangmin , Huh June , Park Cheolmin
Published: May 2017

A triboelectric nanogenerators (TENG) are of great interest as emerging power harvesters because of their simple device architecture with unprecedented high efficiency. Despite the substantial development of new constituent materials and device architectures, a TENG with a switchable surface on a single device, which allows for facile control of the triboelectric output performance, remains a challenge. Here, a supramolecular route for fabricating a novel TENG based on an alkali‐metal‐bound porous film, where the alkali metal ions are readily switched among one another is demonstrated. The soft nanoporous TENG contains numerous SO3− groups on the surface of nanopores prepared from the supramolecular assembly of sulfonic‐acid‐terminated polystyrene and poly(2‐vinylpyridine) (P2VP), followed by soft etching of P2VP. Selective binding of alkali metal ions, including Li+, Na+, K+, and Cs+, with SO3− groups enables the development of mechanically robust alkali‐metal‐ion‐decorated TENGs. The triboelectric output performance of the devices strongly depends on the alkali metal ion species, and the output power ranges from 11.5 to 256.5 µW. This wide‐range triboelectric tuning can be achieved simply by a conventional ion exchange process in a reversible manner, thereby allowing reversible control of the output performance in a single device platform.
Hybrid Perovskites: Effective Crystal Growth for Optoelectronic Applications
Authors: Jeon Taewoo , Kim Sung Jin , Yoon Jisun , Byun Jinwoo , Hong Hye Rim , Lee Tae‐Woo , Kim Ji‐Seon , Shin Byungha , Kim Sang Ouk
Published: May 2017

Outstanding material properties of organic‐inorganic hybrid perovskites have triggered a new insight into the next‐generation solar cells. Beyond solar cells, a wide range of controllable properties of hybrid perovskites, particularly depending on crystal growth conditions, enables versatile high‐performance optoelectronic devices such as light‐emitting diodes, photodetectors, and lasers. This article highlights recent progress in the crystallization strategies of organic–inorganic hybrid perovskites for use as effective light harvesters or light emitters. Fundamental background on perovskite crystalline structures and relevant optoelectronic properties such as optical band‐gap, electron‐hole behavior, and energy band alignment are given. A detailed overview of the effective crystallization methods for perovskites, including thermal treatment, additives, solvent mediator, laser irradiation, nanostructure, and crystal dimensionalityis reported offering a comprehensive correlation among perovskite processing conditions, crystalline morphology, and relevant device performance. Finally, future research directions to overcome current practical bottlenecks and move towards reliable high performance perovskite optoelectronic applications are proposed.
Gravity induced coalescence in emulsions with high volume fractions of dispersed phase in the presence of surfactants
Authors: Mazumdar Meenakshi , Roy Shantanu
Published: May 2017

We report studies on the effect of volume fraction and surfactant concentration on the kinetics of destabilization of emulsions under the influence of gravity. Model oil‐in‐water emulsions, designed to mimic crude oil–water emulsions, were prepared with varying volume fractions of dispersed oil but nearly identical normalized initial drop size distributions. The gravity separation process was observed by periodically withdrawing samples, and examining the droplet size distribution under the microscope. Experiments were performed for three volume fractions of dispersed phase and two surfactant concentrations (0.4 and 1.6% by weight). At higher oil fractions (20%) and a lower surfactant concentration (0.4%), it was observed that although the rate of coalescence increased, the actual oil separation was delayed. At higher surfactant concentrations (1.6%), the dominant factor in suppressing destabilization is the rate of drop to interface coalescence. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4379–4389, 2017
Molecular transport through mixed matrix membranes: A time‐dependent density functional approach
Authors: Liu Yu , Guo Fangyuan , Hu Jun , Liu Honglai , Hu Ying
Published: May 2017

The transport properties of gases in mixed matrix membranes (MMMs) are important in materials design. Here, a novel time‐dependent density functional theory (TDDFT) method to study the transport properties of gases in MMMs is developed. The MMM is modeled by inserting a spherical filler into the continuous polymer phase, which is similar to the Maxwell model; additionally, the inhomogeneity of the filler and the molecular correlations were taken into account in the TDDFT method. Transport properties such as permeation, density profile, flux, and chemical potential are examined and discussed. TDDFT prediction of the permeation is found to be higher than that of the Maxwell model, and the filler‐polymer interface is key to tuning this effect, which also seems to be the dominating factor in the transport process on both the microscopic and macroscopic scale. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4586–4594, 2017
Intramolecular Pictet–Spengler Reaction of Cyclic Iminium ions: A Novel Access to Benzo[1,4]oxazepine‐Fused Tetrahydroisoquinoline and Tetrahydro‐β‐carboline Analogues
Authors: Unnava Ramanjaneyulu , Sahu Archana K. , Saikia Anil K.
Published: May 2017

A simple and efficient approach has been developed for the synthesis of benzo[1,4]oxazepino‐fused tetrahydroisoquinoline and tetrahydro‐β‐carboline derivatives via one‐pot cascade reaction sequence. This reaction involves the intramolecular Pictet–Spengler reaction of cyclic iminium ions, which were generated in situ via trifluoroacetic acid (TFA)‐mediated deprotection of an acetal derived from β‐arylethylamines and 2‐(2,2‐diethoxyethoxy)benzaldehyde. All reactions produced a novel library of complex fused polyheterocyclic compounds in good to excellent yields.
Silver Films with Hierarchical Chirality
Authors: Ma Liguo , Cao Yuanyuan , Duan Yingying , Han Lu , Che Shunai
Published: May 2017

Physical fabrication of chiral metallic films usually results in singular or large‐sized chirality, restricting the optical asymmetric responses to long electromagnetic wavelengths. The chiral molecule‐induced formation of silver films prepared chemically on a copper substrate through a redox reaction is presented. Three levels of chirality were identified: primary twisted nanoflakes with atomic crystal lattices, secondary helical stacking of these nanoflakes to form nanoplates, and tertiary micrometer‐sized circinates consisting of chiral arranged nanoplates. The chiral Ag films exhibited multiple plasmonic absorption‐ and scattering‐based optical activities at UV/Vis wavelengths based on their hierarchical chirality. The Ag films showed chiral selectivity for amino acids in catalytic electrochemical reactions, which originated from their primary atomic crystal lattices.
Highly Luminescent and Ultrastable CsPbBr3 Perovskite Quantum Dots Incorporated into a Silica/Alumina Monolith
Authors: Li Zhichun , Kong Long , Huang Shouqiang , Li Liang
Published: May 2017

We successfully prepared QDs incorporated into a silica/alumina monolith (QDs‐SAM) by a simple sol–gel reaction of an Al–Si single precursor with CsPbBr3 QDs blended in toluene solution, without adding water and catalyst. The resultant transparent monolith exhibits high photoluminescence quantum yields (PLQY) up to 90 %, and good photostability under strong illumination of blue light for 300 h. We show that the preliminary ligand exchange of didodecyl dimethyl ammonium bromide (DDAB) was very important to protect CsPbBr3 QDs from surface damages during the sol–gel reaction, which not only allowed us to maintain the original optical properties of CsPbBr3 QDs but also prevented the aggregation of QDs and made the monolith transparent. The CsPbBr3 QDs‐SAM in powder form was easily mixed into the resins and applied as color‐converting layer with curing on blue light‐emitting diodes (LED). The material showed a high luminous efficacy of 80 lm W−1 and a narrow emission with a full width at half maximum (FWHM) of 25 nm.
Steuerung der Produktverteilung und der Mechanismen der thermischen Aktivierung von Methan durch Ligandeneffekte und elektrische Felder
Authors: Yue Lei , Li Jilai , Zhou Shaodong , Sun Xiaoyan , Schlangen Maria , Shaik Sason , Schwarz Helmut
Published: May 2017

Die Bindung von Acetonitril an zweiatomiges [ZnO].+ führt bei der thermischen Aktivierung von Methan in der Gasphase zu einem unerwarteten Wechsel der Reaktionsmechanismen und einer Umverteilung der Produkte. Theoretischen Studien zufolge spielt die starke Metall‐Kohlenstoff‐Bindung bei der ligandenfreien [ZnO].+‐Spezies eine bedeutende Rolle für die Rückbindung des CH3.‐Radikals an das Metallzentrum; hierdurch wird die kompetitive Bildung von CH3., OH. und CH3OH ermöglicht. Diese Wechselwirkung wird durch einen CH3CN‐Liganden drastisch reduziert, was mechanistisch zu einem Wechsel von der bei [ZnO].+/CH4 dominierenden protonengekoppelten Elektronenübertragung zum klassischen Wasserstoffatomtransfer, gefolgt von der ausschließlichen Abspaltung von CH3., führt. Dieser Ligandeneffekt kann durch das gerichtete externe elektrische Feld einer negativen Punktladung gut modelliert werden.
Amorphous silicon carbonitride thin‐film coatings produced by remote nitrogen microwave plasma chemical vapour deposition using organosilicon precursor
Authors: Wrobel A.M. , Uznanski P. , Walkiewicz‐Pietrzykowska A. , Jankowski K.
Published: May 2017

Amorphous silicon carbonitride (a‐SiCN) films were produced by remote nitrogen plasma chemical vapour deposition (RP‐CVD) from bis(dimethylamino)methylsilane precursor. The effect of substrate temperature (TS) on the kinetics of RP‐CVD, chemical structure, surface morphology and some properties of the resulting films is reported. The TS dependence of film growth rate implies that RP‐CVD is an adsorption‐controlled process. Fourier transform infrared spectroscopic examination revealed that an increase in TS from 30 to 400°C involves the elimination of organic moieties from the film and the formation of Si─C and Si─N network structure. The films were characterized in terms of their surface roughness and basic physical and optical properties, such as density and refractive index, respectively. Reasonably good relationships between the structural parameters represented by relative integrated intensity of infrared absorption bands from the Si─C and Si─N bonds (controlled by TS) and the film properties are determined. Due to their small surface roughness, high density and high refractive index, the a‐SiCN films produced at TS ≥ 350°C would seem to be useful protective coatings for metals and optical devices.
Effects of temperature and strain rate on the tensile behavior of polypropylene composites insulator coatings used in offshore deepwater pipelines
Authors: Vipulanandan C. , Ahossin Guezo Y. J.
Published: May 2017

Polypropylene (PP) composites are being increasingly used as thermal insulation coatings in both onshore and offshore pipelines. In this study, the direct tensile behavior of pure PP, PP with glass microsphere filler, and PP with 65% glass filler were investigated at 22, 60, and 90 °C temperatures at various strain rates from 0.003/min to 0.300/min. Fourier transform infrared spectroscopy and scanning electron microscope studies were used to characterize the materials. Stress–strain relationships of the materials were nonlinear in the elastic and inelastic domains. Addition of glass fiber to the PP increased the elastic modulus, but the yield strength and yield strain were reduced along with the ductility. Based on the experimental results, constitutive models coupling the strain rate and temperature have been developed to predict the yield strength, the initial elastic modulus and secant modulus at yield for the PP composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45209.
Polypropylene/multiwall carbon nanotubes nanocomposites: Nanoindentation, dynamic mechanical, and electrical properties
Authors: Chafidz Achmad , Rengga Wara Dyah Pita , Khan Rawaiz , Kaavessina Mujtahid , Almutlaq Abdulaziz M. , Almasry Waheed A. , Ajbar Abdelhamid
Published: May 2017

Polypropylene (PP)/Multiwall carbon nanotubes (MWCNTs) nanocomposites were fabricated via melt compounding that utilizes a corotating twin‐screw extruder. Two commercially available MWCNTs, Baytubes C150P and C70P, were incorporated into PP matrix at concentration of 3 wt %. The nanocomposites samples were analyzed using scanning electron microscopy, dynamic mechanical analysis (DMA), nanoindentation test, and picoammeter. It was found that both MWCNTs types were well distributed and dispersed in the PP matrix and no agglomeration of MWCNTs was observed. The DMA analysis results showed that the incorporation of MWCNTs enhanced the storage modulus and thermal stability of the PP matrix. Whereas, nanoindentation creep results showed that the creep rate and displacement of the PP/MWCNTs nanocomposites was lower than the neat PP, in which C70P < C150P < PP. The reduction of creep rate and creep displacement was associated to the improvement of creep resistance. There were also improvements on hardness and stiffness of the nanocomposites. Additionally, the electrical resistivity of the neat PP decreased with the incorporation of MWCNTs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45293.
Coccygeal body revisited: An immunohistochemical study using donated elderly cadavers
Authors: Jin Zhe Wu , Cho Kwang Ho , Jang Hyung Suk , Murakami Gen , Rodríguez‐Vázquez Jose Francisco , Yamamoto Masahito , Abe Shin‐Ichi
Published: May 2017

To describe the normal anatomy and histology of the adult coccygeal body (CB) and to discuss about the origin and function, using immunohistochemistry, we examined 29 CBs found in 32 elderly donated cadavers without macroscopic pathology in the pelvis. The CB was usually located in or near the anococcygeal ligaments. It was almost always composed of multiple masses or nodules of round glomus cells (smooth muscle actin or SMA++). However, the CB sometimes contained abundant dilated veins with scattered glomus cells. Thus, the CBs varied from the glomus cell nodule‐dominant type, through an intermediate morphology with a mixture of nodules and veins, to the vein‐dominant type. Each glomus cell mass was surrounded by abundant sympathetic nerves. In all specimens, we found multiple abnormal arteries, each of which carried a glomus‐like cell layer around the almost ‐obliterated vascular lumen; as well as an SMA‐negative thick arterial wall containing abundant sympathetic nerves. The ligaments around the CB are known to be under strong mechanical stress from the pelvic floor. We considered abnormal arteries containing the unique internal layer as an intermediate between a normal muscular artery and a glomus cell mass of CB. Under long‐termed mechanical stress, a muscular artery seems to lose smooth muscles with increased sympathetic nerve fibers, to compensate for the lack of muscle function. Taken together with fetal morphology (our recent report), some or most of the CBs might not be an arteriovenous shunt but a result of stress‐induced acquired transformation of pericytes. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1826–1837, 2017. © 2017 Wiley Periodicals, Inc.
Classic Galactosemia: Study on the Late Prenatal Development of GALT Specific Activity in a Sheep Model
Authors: Coelho Ana I. , Bierau Jörgen , Lindhout Martijn , Achten Jelle , Kramer Boris W. , Rubio‐Gozalbo M. Estela
Published: May 2017

Classic galactosemia results from deficient activity of galactose‐1‐phosphate uridylyltransferase (GALT), a key enzyme of galactose metabolism. Despite early diagnosis and early postnatal therapeutic intervention, patients still develop neurologic and fertility impairments. Prenatal developmental toxicity has been hypothesized as a determinant factor of disease. In order to shed light on the importance of prenatal GALT activity, several studies have examined GALT activity throughout development. GALT was shown to increase with gestational age in 7‐28 weeks human fetuses; later stages were not investigated. Prenatal studies in animals focused exclusively on brain and hepatic GALT activity. In this study, we aim to examine GALT specific activity in late prenatal and adult stages, using a sheep model. Galactosemia acute target‐organs—liver, small intestine and kidney—had the highest late prenatal activity, whereas the chronic target‐organs—brain and ovary—did not exhibit a noticeable pre‐ or postnatal different activity compared with nontarget organs. This is the first study on GALT specific activity in the late prenatal stage for a wide variety of organs. Our findings suggest that GALT activity cannot be the sole pathogenic factor accounting for galactosemia long‐term complications, and that some organs/cells might have a greater susceptibility to galactose toxicity. Anat Rec, 300:1570–1575, 2017. © 2017 Wiley Periodicals, Inc.
Dynamical Analysis of a Tri‐Neuron Fractional Network
Authors: Huang Cheng‐dai , Cao Jin‐de , Xiao Min , Alsaedi Ahmed , Alsaadi Fuad E. , Hayat Tasawar
Published: May 2017

The present paper concerns with the dynamics of a fractional neural network involving three neurons. Firstly, the bifurcation point is identified for which Hopf bifurcations may occur by taking the system parameter as a bifurcation parameter via the stability analysis of fractional systems. It is indicated that the system parameter can significantly affect the dynamical properties of such network. Secondly, the impact of the order on the bifurcation point is carefully examined. It is found that the occurrence of bifurcation is delayed as the order increases as long as the other system parameters are established. Finally, a numerical example is exploited to verify the efficiency of theoretical results.
Glycocalyx bending by an electric field increases cell motility
Authors: Hart Francis X. , Palisano John R.
Published: May 2017

The application of physiological strength electric fields may produce a wide range of effects on cells. The mechanisms by which cells detect the presence of these fields, however, are not fully understood. Previous experiments have shown that directionality of cells in the field is governed by an electromechanical mechanism in which the field exerts a torque on the negatively charged, inner glycocalyx that is then transmitted as a force on the cytoskeleton. This mechanism is similar to that by which cells detect fluid shear forces. Several authors, however, have reported that cell directionality and motility behave differently in an electric field. We propose here a second electromechanical mechanism in which the field bends the negatively charged, outer glycocalyx in proximity to the substrate, increasing cell adhesion and, thus, cell motility. The increase in motility depends not only on the field strength, but also on the adhesion of the cell to the substrate prior to application of the field. We show that these mechanisms are common to both human cells and amoebae and, hence, are evolutionarily conserved. Furthermore, the mechanism for detection of electric fields is simply an extension of the mechanism for detecting fluid shears. Bioelectromagnetics. 38:482–493, 2017. © 2017 Wiley Periodicals, Inc.
Tryptase expression as a prognostic marker in patients with resected gastric cancer
Authors: Lin C , Liu H , Zhang H , Cao Y , Li R , Wu S , Li H , He H , Xu J , Sun Y
Published: May 2017

Background

Mast cells play important roles in the progression of various malignancies, but their prognostic value in gastric cancer is unknown. Tryptase expression, as an indicator of mast cell activity, was therefore evaluated to see whether this could be incorporated usefully into a prognostic nomogram after surgery in patients with gastric cancer.

Methods

Tissue microarrays from patients with gastric cancer were created from formalin-fixed, paraffin-embedded resection specimens. Tryptase density was assessed by immunohistochemistry, and the association between tryptase expression and prognosis was evaluated. Semiquantitative scoring was devised to determine an optimal cut-off value that correlated with survival. A prognostic nomogram was then developed incorporating tryptase expression scores along with other variables known to be related to survival.

Results

Tissue microarrays were generated from 419 patients having surgery for gastric cancer. Increased tryptase expression was associated with better overall and recurrence-free survival (both P < 0·001). Tryptase expression was an independent favourable prognostic factor for overall (HR 0·72; P = 0·027) and recurrence-free (HR 0·74; P = 0·044) survival. The accuracy of an established prognostic model was improved when tryptase expression was added.

Conclusion

Tryptase expression is an independent prognostic factor for overall and recurrence-free survival in patients with gastric cancer after surgical resection.
HIV‐1 p55‐gag protein induces senescence of human bone marrow mesenchymal stem cells and reduces their capacity to support expansion of hematopoietic stem cells in vitro
Authors: Yuan Ya‐hong , Zhao Shan‐shan , Wang Xiao‐li , Teng Zhi‐ping , Li Dong‐sheng , Zeng Yi
Published: May 2017

Patients with human immunodeficiency virus‐1 (HIV‐1) infection often present with hematopoietic failure. As the important hematopoietic support cells in the bone marrow (BM), the BM mesenchymal stem cells (BMSCs) can be impacted by HIV proteins that are released by infected cells within BM. In this study, we tested whether HIV protein p55‐gag could induce senescence of BMSCs and reduce their capacity to support expansion of hematopoietic stem cells in vitro. BMSCs were chronically treated with p55‐gag (BMSCgag) for up to 20 days, and their proliferative activity and senescence makers were compared to nontreated cells (BMSCcon). Then, we analyzed the hematopoietic support function of BMSCcon and BMSCgag by determining cellular proliferation, colony‐forming ability, and primitive hematopoietic populations of hematopoietic progenitors grown on the BMSCs. In addition, we compared the gene expression patterns for supporting hematopoiesis of BMSCcon and BMSCgag. The results show that when compared to BMSCcon, BMSCgag reduced their proliferative activity and underwent senescence. The ability of BMSCgag to support the expansion of committed hematopoietic progenitors from umbilical cord blood‐derived CD34+cells may be impaired, while the expression of genes associated with maintaining and enhancing hematopoiesis appeared to be decreased in treated BMSCs compared to control BMSCs. In conclusion, senescence induced by p55‐gag resulted in decreased hematopoietic support function of BMSCs through reducing a series of hematopoietic cytokine expression.
Knock‐down of farnesyl pyrophosphate synthase protects heart‐derived H9c2 cells against hypoxia/reoxygenation‐induced injury
Authors: Dai Dongpu , Wu Huandong , Yang Jian , Shen Shizhen , Zhao Chenze , Ding Jie , Hu Shenjiang
Published: May 2017

Farnesyl pyrophosphate synthase (FPPS) is a key enzyme in the mevalonate pathway. Our previous studies have indicated that cardiac‐specific overexpression of FPPS induces cardiac hypertrophy and dysfunction in mice, and inhibition of FPPS prevents angiotensin (Ang) II‐induced hypertrophy in cardiomyocytes. However, the role for FPPS in myocardial ischemia/reperfusion (MIR) injury is still not clear. The objective of this work was to investigate the effect of FPPS on MIR injury in H9c2 cells which were subjected to hypoxia/reoxygenation (HR) to mimic MIR. Prior to HR, cells were transfected with pE‐mFPPS, shFPPS, or pE‐GFP. Our results showed that the overexpression of FPPS reduced cell proliferation, increased cell injury and cell apoptosis, and knock‐down of FPPS improved cell proliferation, decreased cell injury, and cell apoptosis after HR. Besides, overexpression of FPPS increased Rac1 activity and reactive oxygen species (ROS) generation, while FPPS silencing decreased Rac1 activity and ROS generation. Based on these findings, we propose that knock‐down of FPPS reduces Rac1 activity and ROS production, and finally leads to the decrease of HR‐induced injury in H9c2 cells. These findings point that FPPS might be a potential target in preventing H9c2 cells from HR‐induced injury.
Bone marrow‐derived cells response in proximal regions of nerves after peripheral nerve injury
Authors: Chen Lulu , Cheng Jia , Yang Xiaonan , Jin Xiaolei , Qi Zuoliang , Jin Yu‐Qing
Published: May 2017

In recent years, bone marrow‐derived cells have been found to be crucial for peripheral nerve regeneration. After traumatic peripheral nerve injury, bone marrow‐derived macrophages quickly infiltrate into the distal regions of nerves. To explore the changes caused by bone marrow‐derived cells within the proximal regions of the nerves, sciatic nerves of chimeric mice carrying bone marrow cells expressing green fluorescent protein were crushed to observe the infiltration of invading bone marrow‐derived cells. Seven days after surgery, abundant bone marrow‐derived cells had infiltrated into the damaged proximal nerve segments. The numbers of these cells increased to a peak at 2 weeks and then gradually returned to normal levels within 30 weeks. Through immunofluorescence staining, many of these cells were identified as macrophages, and they showed a similar infiltration tendency toward distal nerve segments. However, fewer cells infiltrated proximal segments than distal nerve segments. In conclusion, these findings suggest that bone marrow‐derived cells response not only occurs within the distal nerve segments but may also take place within the proximal segments of nerve tissues after nerve injury.
Synthesis of Iminosugar‐Containing KRN7000 Analogues
Authors: Zhang Lei , Ye Xin‐Shan
Published: May 2017

Three new iminosugar‐containing KRN7000 (also referred to as α‐GalCer) analogues were designed and synthesized. In the design, the galactose moiety of KRN7000 was replaced by iminosugars and the iminosugar structures were connected with ceramide in different manners with a C‐glycosidic bond instead of the O‐glycosidic bond. To our knowledge, this is the first report in which iminosugars are incorporated in KRN7000 structure modifications. The synthetic compounds were evaluated for their ability to stimulate cytokine release. The results may benefit better understanding of structure‐activity relationships and facilitate future design of more KRN7000 derivatives.
Fine needle aspiration cytology of primary cutaneous mucinous carcinoma of axilla‐report of a rare case
Authors: Pal Subrata , Mondal Palash Kr , Pradhan Rajashre , Sharma Abhishek , Biswas Biswajit , Bhattacharyya Subodh
Published: May 2017

Primary mucinous eccrine carcinoma is a rare malignant adnexal tumor of older patients. The histopathological features of this tumor are well‐established but the cytomorphology of this neoplasm has only been documented in a few cases. The cytology and histology of this tumor may mimic metastatic mucinous carcinoma and may cause a diagnostic dilemma, especially when the tumor is located at axilla. A correct diagnosis is important because the prognosis is better than that of a metastatic mucinous carcinoma. Here we report the cytological and histological features of a case of primary cutaneous mucinous carcinoma of axilla in an elderly male patient.