bluuebunny/crossref_metadata_2025 huggingface dataset:
Electric Mars: The first direct measurement of an upper limit for the Martian “polar wind” electric potential
Authors: Collinson Glyn , Mitchell David , Glocer Alex , Grebowsky Joseph , Peterson W. K. , Connerney Jack , Andersson Laila , Espley Jared , Mazelle Christian , Sauvaud Jean‐André , Fedorov Andrei , Ma Yingjuan , Bougher Steven , Lillis Robert , Ergun Robert , Jakosky Bruce
Published: November 2015

An important mechanism in the generation of polar wind outflow is the ambipolar electric potential which assists ions in overcoming gravity and is a key mechanism for Terrestrial ionospheric escape. At Mars, open field lines are not confined to the poles, and outflow of ionospheric electrons is observed far into the tail. It has thus been hypothesized that a similar electric potential may be present at Mars, contributing to global ionospheric loss. However, no direct measurements of this potential have been made. In this pilot study, we examine photoelectron spectra measured by the Solar Wind Electron Analyzer instrument on the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) Mars Scout to put an initial upper bound on the total potential drop in the ionosphere of Mars of
, with the possibility of a further
4.5 V potential drop above this in the magnetotail. If the total potential drop was close to the upper limit, then strong outflows of major ionospheric species (H+, O+, and
) would be expected. However, if most of the potential drop is confined below the spacecraft, as expected by current theory, then such a potential would not be sufficient on its own to accelerate
to escape velocities, but would be sufficient for lighter ions. However, any potential would contribute to atmospheric loss through the enhancement of Jeans escape.
Magnetotail dynamics at Mars: Initial MAVEN observations
Authors: DiBraccio Gina A. , Espley Jared. R. , Gruesbeck Jacob R. , Connerney John E. P. , Brain David A. , Halekas Jasper S. , Mitchell David L. , McFadden James P. , Harada Yuki , Livi Roberto , Collinson Glyn , Hara Takuya , Mazelle Christian , Jakosky Bruce M.
Published: November 2015

We report on the complex nature of the induced Martian magnetotail using simultaneous magnetic field and plasma measurements from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. Two case studies are analyzed from which we identify (1) repetitive loading and unloading of tail magnetic flux as the field magnitude changes dramatically, exhibiting signatures similar to substorm activity within intrinsic magnetospheres; (2) multiple current sheet crossings indicative of plasma sheet flapping; (3) tailward flowing high‐energy planetary ions (O+ and O2+), confined exclusively to the cross‐tail current sheet, contributing to atmospheric escape; and (4) signatures of magnetic flux ropes, suggesting the occurrence of tail reconnection. These events illustrate the complexity of the Martian magnetotail as MAVEN provides key observations relevant to the unanswered questions of induced magnetosphere dynamics.
Three‐dimensional structure in the Mars H corona revealed by IUVS on MAVEN
Authors: Chaffin M. S. , Chaufray J. Y. , Deighan J. , Schneider N. M. , McClintock W. E. , Stewart A. I. F. , Thiemann E. , Clarke J. T. , Holsclaw G. M. , Jain S. K. , Crismani M. M. J. , Stiepen A. , Montmessin F. , Eparvier F. G. , Chamberlain P. C. , Jakosky B. M.
Published: November 2015

Loss of water to space via neutral hydrogen escape has been an important process throughout Martian history. Contemporary loss rates can be constrained through observations of the extended neutral hydrogen atmosphere of Mars in scattered sunlight at 121.6 nm. Historically, such observations have been interpreted with coupled density and radiative transfer models, inferring escape fluxes from brightness profiles gathered by flybys, orbiters, and telescope observations. Here we demonstrate that the spherical symmetry assumed by prior analyses cannot reproduce observations by the Imaging Ultraviolet Spectrograph (IUVS) on the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. We present unique observations of the Mars H corona to large radial distances and mapping results from initial MAVEN science at Mars. These observations represent the first detection of three‐dimensional structure in the H corona of Mars, with implications for understanding the atmosphere today and the loss of H to space throughout Martian history.
Response of Mars O+ pickup ions to the 8 March 2015 ICME: Inferences from MAVEN data‐based models
Authors: Curry S. M. , Luhmann J. G. , Ma Y. J. , Dong C. F. , Brain D. , Leblanc F. , Modolo R. , Dong Y. , McFadden J. , Halekas J. , Connerney J. , Espley J. , Hara T. , Harada Y. , Lee C. , Fang X. , Jakosky B.
Published: November 2015

We simulate and compare three phases of the Mars‐solar wind interaction with the 8 March interplanetary coronal mass ejection (ICME) event using Mars Atmosphere and Volatile EvolutioN (MAVEN) mission observations in order to derive heavy ion precipitation and escape rates. The MAVEN observations provide the initial conditions for three steady state MHD model cases, which reproduce the observed features in the solar wind density, velocity, and magnetic field seen along the MAVEN orbit. Applying the MHD results to a kinetic test particle model, we simulate global precipitation and escape maps of O+ during the (1) pre‐ICME phase, (2) sheath phase, and (3) ejecta phase. We find that the Case 1 had the lowest precipitation and escape rates of 9.5 × 1025 and 4.1 × 1025 s−1, Case 2 had the highest rates of 9.5 × 1025 and 4.1 × 1025 s−1, and Case 3 had rates of 3.2 × 1025 and 1.3 × 1025 s−1, respectively. Additionally, Case 2 produced a high‐energy escaping plume >10 keV, which mirrored corresponding STATIC observations.
Water and water ions in the Martian thermosphere/ionosphere
Authors: Fox Jane L. , Benna M. , Mahaffy P. R. , Jakosky B. M.
Published: November 2015

First results from the Neutral Gas and Ion Mass Spectrometer instrument on the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft reveal density profiles of protonated species that are mostly in good qualitative agreement with recent models of the Martian thermosphere/ionosphere. We present here the first photochemical model in which the density profiles of water and water ions in the ionosphere/thermosphere are predicted. We find that the computed peak densities of OH+, H2O+, and H3O+ are in fairly good agreement with the measured values. The computed column density of water is predicted to be about 1010 cm−2, and the mixing ratio at 80 km is 0.4 ppb. The actual water densities must be small enough so that HCO+ is not destroyed by proton transfer to water during the daytime and large enough so that H3O+ dominates the ionosphere at low altitudes just beyond the terminator. The calculations also show that the mass‐2 ion is almost certainly H
.
First measurements of composition and dynamics of the Martian ionosphere by MAVEN's Neutral Gas and Ion Mass Spectrometer
Authors: Benna M. , Mahaffy P. R. , Grebowsky J. M. , Fox J. L. , Yelle R. V. , Jakosky B. M.
Published: November 2015

We report the results of the observations of the ionosphere of Mars by the Neutral Gas and Ion Mass Spectrometer. These observations were conducted during the first 8 months of the Mars Atmosphere and Volatile EvolutioN mission (MAVEN). These observations revealed the spatial and temporal structures in the density distributions of 22 ions: H2+, H3+, He+, O2+, C+, CH+, N+, NH+, O+, OH+, H2O+, H3O+, N2+/CO+, HCO+/HOC+/N2H+, NO+, HNO+, O2+, HO2+, Ar+, ArH+, CO2+, and OCOH+. Dusk/dawn and day/night asymmetries in the density distributions were observed for nearly all ion species. Additionally, high‐density fluctuations were detected on the nightside and may reflect the effect of the partial screening of the atmosphere of Mars by the weak intrinsic magnetic field of the planet. The two first MAVEN “deep dip” campaigns were used to investigate the location of the primary ion peak. This peak was detected at 190 km near the terminator but was below the spacecraft altitude of 130 km near the subsolar point.
Dissolved inorganic carbon budgets in the eastern subpolar North Atlantic in the 2000s from in situ data
Authors: Zunino Patricia , Lherminier Pascale , Mercier Herlé , Padín Xose A. , Ríos Aida F. , Pérez Fiz F.
Published: November 2015

The subpolar North Atlantic (SPNA) is important in the global carbon cycle because of the deep water ventilation processes that lead to both high uptake of atmospheric CO2 and large inventories of anthropogenic CO2 (Cant). Thus, it is crucial to understand its response to increasing anthropogenic pressures. In this work, the budgets of dissolved inorganic carbon (DIC), Cant and natural DIC (DICnat) in the eastern SPNA in the 2000s, are jointly analyzed using in situ data. The DICnat budget is found to be in steady state, confirming a long‐standing hypothesis from in situ data for the first time. The biological activity is driving the uptake of natural CO2 from the atmosphere. The Cant increase in the ocean is solely responsible of the DIC storage rate which is explained by advection of Cant from the subtropics (65%) and Cant air‐sea flux (35%). These results demonstrate that the Cant is accumulating in the SPNA without affecting the natural carbon cycle.
Nonmigrating tides in the Martian atmosphere as observed by MAVEN IUVS
Authors: Lo Daniel Y. , Yelle Roger V. , Schneider Nicholas M. , Jain Sonal K. , Stewart A. Ian F. , England Scott L. , Deighan Justin I. , Stiepen Arnaud , Evans J. Scott , Stevens Michael H. , Chaffin Michael S. , Crismani Matteo M. J. , McClintock William E. , Clarke John T. , Holsclaw Gregory M. , Lefèvre Franck , Jakosky Bruce M.
Published: November 2015

Using the Mars Atmospheric and Volatile EvolutioN mission (MAVEN) Imaging Ultraviolet Spectrograph (IUVS), we found periodic longitudinal variations in CO2 density in the Martian atmosphere. These density variations are derived from observations of the
(
) emission from limb scans in the 100–190 km altitude range. The variations exhibit significant structure with longitudinal wave numbers 1, 2, and 3 in an effectively constant local solar time frame, and we attribute this structure to nonmigrating tides. The wave‐2 component is dominated by the diurnal eastward moving DE1 tide at the equator and the semidiurnal stationary S0 tide at the midlatitudes. Wave‐3 is dominated by the diurnal eastward moving DE2 tide, with possibly the semidiurnal eastward moving SE1 tide causing an amplitude increase at the midlatitudes. Structure in the wave‐1 component can be explained by the semidiurnal westward moving SW1 tide.
The nonlinear relationship between albedo and cloud fraction on near‐global, monthly mean scale in observations and in the CMIP5 model ensemble
Authors: Engström A. , Bender F. A.‐M. , Charlson R. J. , Wood R.
Published: November 2015

We study the relation between monthly mean albedo and cloud fraction over ocean, 60°S–60°N. Satellite observations indicate that these clouds all fall on the same near‐exponential curve, with a monotonic distribution over the ranges of cloud fractions and albedo. Using these observational data as a reference, we examine the degree to which 26 climate models capture this feature of the near‐global marine cloud population. Models show a general increase in albedo with increasing cloud fraction, but none of them display a relation that is as well defined as that characterizing the observations. Models typically display larger albedo variability at a given cloud fraction, larger sensitivity in albedo to changes in cloud fraction, and lower cloud fractions. Several models also show branched distributions, contrasting with the smooth observational relation. In the models the present‐day cloud scenes are more reflective than the preindustrial, demonstrating the simulated impact of anthropogenic aerosols on planetary albedo.
A comet engulfs Mars: MAVEN observations of comet Siding Spring's influence on the Martian magnetosphere
Authors: Espley Jared R. , DiBraccio Gina A. , Connerney John E. P. , Brain David , Gruesbeck Jacob , Soobiah Yasir , Halekas Jasper , Combi Michael , Luhmann Janet , Ma Yingjuan , Jia Yingdong , Jakosky Bruce
Published: November 2015

The nucleus of comet C/2013 A1 (Siding Spring) passed within 141,000 km of Mars on 19 October 2014. Thus, the cometary coma and the plasma it produces washed over Mars for several hours producing significant effects in the Martian magnetosphere and upper atmosphere. We present observations from Mars Atmosphere and Volatile EvolutioN's (MAVEN's) particles and field's instruments that show the Martian magnetosphere was severely distorted during the comet's passage. We note four specific major effects: (1) a variable induced magnetospheric boundary, (2) a strong rotation of the magnetic field as the comet approached, (3) severely distorted and disordered ionospheric magnetic fields during the comet's closest approach, and (4) unusually strong magnetosheath turbulence lasting hours after the comet left. We argue that the comet produced effects comparable to that of a large solar storm (in terms of incident energy) and that our results are therefore important for future studies of atmospheric escape, MAVEN's primary science objective.
First detection of the supersonic upward plasma flow structures in the early morning sector
Authors: Astafyeva Elvira , Zakharenkova Irina
Published: November 2015

We present the first observations of the supersonic updrafting plasma drifts in the predawn sector. Two DMSP satellites quasi‐simultaneously detected two fast‐speed events: one of ~385 km spatial extension and with the maximum upward velocity of 1683 m/s appeared at ~3 LT, and the other of ~1500 km large with maximum speed of 1770 m/s occurred at ~5 LT. Both supersonic structures were observed above the eastern Pacific region, separated by ~35° of longitude in space and by 45 min in time. The events occurred at the recovery phase of the geomagnetic storm of 19 February 2014, during rapid oscillations of the interplanetary magnetic field Bz and the interplanetary electric field Ey components, which increased the eastward electric field in the equatorial nighttime ionosphere and triggered the generation of plasma irregularities. The storm time penetration electric fields seem to be the principal driver of the observed supersonic events.
Origin of variability in Northern Hemisphere winter blocking on interannual to decadal timescales
Authors: Gollan Gereon , Greatbatch Richard J. , Jung Thomas
Published: November 2015

Variability of midlatitude blocking in the boreal winter Northern Hemisphere is investigated for the period 1960/1961 to 2001/2002 by means of relaxation experiments with the model of the European Centre for Medium‐Range Weather Forecasts. It is shown that there is pronounced interannual and decadal variability in blocking, especially over the Eurasian continent, consistent with previous studies. The relaxation experiments show that realistic variability in the tropics can account for a significant part of observed interannual blocking variability but also that about half of the observed variability can only be explained by extratropical tropospheric variability. On the quasi‐decadal timescale, extratropical sea surface temperature and sea ice, in addition to tropical variability, play a more important role. The stratosphere, which has been shown to influence interannual variability of the North Atlantic Oscillation in previous studies, has no significant influence on blocking according to our analysis.
Climatology and trends of tropical cyclone high wind in mainland China: 1959–2011
Authors: Ni Xiang , Zhang Qinghong , Ma Ding , Wu Liguang , Ren Fumin
Published: November 2015

The climatology and trends of tropical cyclone (TC) high wind (TCHW; wind speeds ≥10.8 m s−1) in mainland China during 1959–2011 were studied based on a comprehensive series of surface wind observations from 574 stations. Of these stations, 41 were affected by TCHW more than once per year and were mainly located along the southeast coastline or at some inland mountain locations. The contribution of TCHW frequency to high wind (HW; wind speeds ≥10.8 m s−1) frequency was highest along the southeast coastline of China and decreased rapidly at inland locations. Both the TCHW frequency (intensity) and HW frequency (intensity) displayed significant downward (weakened) trends after the 1980s. The proportion of HW events accounted for by TCHW decreased, although the trend was not significant. The changes in TCHW frequency and intensity were associated with variations in the number of influencing TCs (ITC: a TC that causes at least one TCHW event), ITCTs (ITC time: an observation time with ITCs), the range of ITC influence, and ITC intensity and track. The annual number of ITCs and ITCTs declined consistently during the study period. The range of ITC influence as related to the TC size in 1983–2011 was smaller than in 1959–1982. The variation of the percentiles of ITC intensity showed an increasing (decreasing) trend of weaker (stronger) ITCs. Years with the maximum TCHW frequency had more ITCs and ITCTs than those with the minimum TCHW frequency.
The deformation record of olivine in mylonitic peridotites from the Finero Complex, Ivrea Zone: Separate deformation cycles during exhumation
Authors: Matysiak Agnes K. , Trepmann Claudia A.
Published: November 2015

Mylonitic peridotites from the Finero complex are investigated to detect characteristic olivine microfabrics that can resolve separate deformation cycles at different metamorphic conditions. The heterogeneous olivine microstructures are characterized by deformed porphyroclasts surrounded by varying amounts of recrystallized grains. A well‐developed but only locally preserved foam structure is present in recrystallized grain aggregates. This indicates an early stage of dynamic recrystallization and subsequent recovery and recrystallization at quasi‐static stress conditions, where the strain energy was reduced such that a reduction in surface energy controlled grain boundary migration. Ultramylonites record a renewed stage of localized deformation and recrystallization by a second generation of recrystallized grains that do not show a foam structure. This second generation of recrystallized grains as well as sutured grain and kink band boundaries of porphyroclasts indicate that these microstructures developed during a stage of localized deformation after development of the foam structure. The heterogeneity of the microfabrics is interpreted to represent several (at least two) cycles of localized deformation separated by a marked hiatus with quasi‐static recrystallization and recovery and eventually grain growth. The second deformation cycle did not only result in reactivation of preexisting shear zones but instead also locally affected the host rock that was not deformed in the first stage. Such stress cycles can result from sudden increases in differential stress imposed by seismic events, i.e., high stress‐loading rates, during exhumation of the Finero complex.
Influence of dynamic factors on nonwetting fluid snap‐off in pores
Authors: Deng Wen , Balhoff Matthew , Cardenas M. Bayani
Published: November 2015

Snap‐off is an important dynamic multiphase flow phenomenon which occurs in porous media. It plays a dominant role in the residual trapping and mobilization/immobilization of nonwetting fluids such as hydrocarbons or CO2. Current studies, applications, and threshold criteria of snap‐off are mostly based on static or equilibrium conditions. Thus, the dynamics of snap‐off which is relevant for many real world applications has rarely been systematically studied. While a static criterion indicates the snap‐off potential for nonwetting fluids, the competition between the time required for snap‐off and the local pore throat capillary number determines whether snap‐off actually occurs. Using a theoretical model to couple the wetting film thickness to the local capillary number at the pore throat, we analyzed the dynamics of the wetting/nonwetting interface instability in sinusoidally constricted capillary tubes. The influence of dynamic factors as encapsulated by the effect of local capillary number on nonwetting fluid snap‐off time were investigated for varying pore throat to pore body aspect ratio and pore body distances. The analysis showed that snap‐off can be inhibited by a sufficiently large local capillary number even in cases where the static snap‐off criterion has been met.
Flash‐Assisted Processing of Highly Conductive Zinc Oxide Electrodes from Water
Authors: Della Gaspera Enrico , Kennedy Danielle F. , van Embden Joel , Chesman Anthony S. R. , Gengenbach Thomas R. , Weber Karl , Jasieniak Jacek J.
Published: November 2015

Fabricating high‐quality transparent conductors using inexpensive and industrially viable techniques is a major challenge toward developing low cost optoelectronic devices such as solar cells, light emitting diodes, and touch panel displays. In this work, highly transparent and conductive ZnO thin films are prepared from a low‐temperature, aqueous deposition method through the careful control of the reaction chemistry. A robotic synthetic platform is used to explore the wide parameter space of a chemical bath system that uses only cheap and earth abundant chemicals for thin film deposition. As‐deposited films are found to be highly resistive, however, through exposure to several millisecond pulses of high‐intensity, broadband light, intrinsically doped ZnO films with sheet resistances as low as 40 Ω □−1 can be readily prepared. Such values are comparable with state‐of‐the‐art‐doped transparent conducting oxides. The mild processing conditions (<150 °C) of the ZnO electrodes also enable their deposition on temperature sensitive substrates such as PET, paving the way for their use in various flexible optoelectronic devices. Proof‐of‐concept light emitting devices employing ZnO as a transparent electrode are presented.
Polydopamine as a Biocompatible Multifunctional Nanocarrier for Combined Radioisotope Therapy and Chemotherapy of Cancer
Authors: Zhong Xiaoyan , Yang Kai , Dong Zhiliang , Yi Xuan , Wang Yong , Ge Cuicui , Zhao Yuliang , Liu Zhuang
Published: November 2015

Development of biodegradable nanomaterials for drug delivery and cancer theranostics has attracted great attention in recent years. In this work, polydopamine (PDA), a biocompatible polymer, is developed as a promising carrier for loading of both radionuclides and an anticancer drug to realize nuclear‐imaging‐guided combined radioisotope therapy (RIT) and chemotherapy of cancer in one system. It is found that PDA nanoparticles after modification with poly(ethylene glycol) (PEG) can successfully load several different radionuclides such as 99mTc and 131I, as well as an anticancer drug doxorubicin (DOX). While labeling PDA‐PEG with 99mTc (99mTc‐PDA‐PEG) enables in vivo single photon emission computed tomography imaging, nanoparticles co‐loaded with 131I and DOX (131I‐PDA‐PEG/DOX) can be utilized for combined RIT and chemotherapy, which offers effective cancer treatment efficacy in a remarkably synergistic manner, without rendering significant toxicity to the treated animals. Therefore, this study presents an interesting class of biocompatible nanocarriers, which allow the combination of RIT and chemotherapy, the two extensively applied cancer therapeutic strategies, promising for future clinic translations in cancer treatment.
Microfluidic‐Spinning‐Directed Microreactors Toward Generation of Multiple Nanocrystals Loaded Anisotropic Fluorescent Microfibers
Authors: Zhang Yan , Wang Cai‐Feng , Chen Li , Chen Su , Ryan Anthony J.
Published: November 2015

Anisotropic fluorescent hybrid microfibers with distinct optical properties and delicate architectures have aroused special interest because of their potential applications in tissue engineering, drug delivery, sensors, and functional textiles. Microfluidic systems have provided an ideal microreactor platform to produce anisotropic fibers due to their simplified manipulation, high efficiency, flexible controllability, and environmental‐friendly chemical process. Here a novel microfiber reactor based on a microfluidic spinning technique for in situ fabrication of nanocrystals loaded anisotropic fluorescent hybrid microfibers is demonstrated. Multiple nanocrystal reactions are carried out in coaxial flow‐based microdevices with different geometric features, and various nanocrystals loaded microfibers with solid, string‐of‐beads and Janus topographies are obtained. Moreover, the resulted anisotropic fluorescent hybrid microfibers present multiple optical signals. This strategy contributes a facile and environmental‐friendly route to anisotropic fluorescent hybrid microfibers and might open a promising avenue to multiplex optical sensing materials.
A Route for Phase Control in Metal Nanoparticles: A Potential Strategy to Create Advanced Materials
Authors: Kusada Kohei , Kitagawa Hiroshi
Published: November 2015

There is untapped potential for materials whose crystal structures are unobtainable in the bulk state. Several examples of such structures have been found in nanomaterials, and these materials exhibit unique properties that arise from their unique electronic states and surface structures. Here, recent developments in the syntheses of these nanomaterials and their unique properties, such as hydrogen‐storage ability and catalytic activity, are summarized. Firstly, the syntheses and properties of novel solid‐solution alloy nanoparticles in immiscible alloy systems such as Ag–Rh and Pd–Ru are introduced. Following this, the crystal structure control of nanoscale Ru is discussed. These unique alloy materials show enhanced properties and highlight the potential of phase control to be a new strategy for nanomaterial development.
Recent Progress in Obtaining Semiconducting Single‐Walled Carbon Nanotubes for Transistor Applications
Authors: Islam Ahmad E. , Rogers John A. , Alam Muhammad A.
Published: November 2015

High purity semiconducting single‐walled carbon nanotubes (s‐SWCNTs) with a narrow diameter distribution are required for high‐performance transistors. Achieving this goal is extremely challenging because the as‐grown material contains mixtures of s‐SWCNTs and metallic‐ (m‐) SWCNTs with wide diameter distributions, typically inadequate for integrated circuits. Since 2000, numerous ex situ methods have been proposed to improve the purity of the s‐SWCNTs. The majority of these techniques fail to maintain the quality and integrity of the s‐SWCNTs with a few notable exceptions. Here, the progress in realizing high purity s‐SWCNTs in as‐grown and post‐processed materials is highlighted. A comparison of transistor parameters (such as on/off ratio and field‐effect mobility) obtained from test structures establishes the effectiveness of various methods and suggests opportunities for future improvements.
Elucidating the Sole Contribution from Electromagnetic Near‐Fields in Plasmon‐Enhanced Cu2O Photocathodes
Authors: DuChene Joseph S. , Williams Benjamin P. , Johnston‐Peck Aaron C. , Qiu Jingjing , Gomes Mathieu , Amilhau Maxime , Bejleri Donald , Weng Jiena , Su Dong , Huo Fengwei , Stach Eric A. , Wei Wei David
Published: November 2015

Despite many promising reports of plasmon‐enhanced photocatalysis, the inability to identify the individual contributions from multiple enhancement mechanisms has delayed the development of general design rules for engineering efficient plasmonic photocatalysts. Herein, a plasmonic photocathode comprised of Au@SiO2 (core@shell) nanoparticles embedded within a Cu2O nanowire network is constructed to exclusively examine the contribution from one such mechanism: electromagnetic near‐field enhancement. The influence of the local electromagnetic field intensity is correlated with the overall light‐harvesting efficiency of the device through variation of the SiO2 shell thickness (5–22 nm) to systematically tailor the distance between the plasmonic Au nanoparticles and the Cu2O nanowires. A threefold increase in device photocurrent is achieved upon integrating the Au@SiO2 nanoparticles into the Cu2O nanowire network, further enabling a 40% reduction in semiconductor film thickness while maintaining photocathode performance. Photoelectrochemical results are further correlated with photoluminescence studies and optical simulations to confirm that the near‐field enhancement is the sole mechanism responsible for increased light absorption in the plasmonic photocathode.
Constructing a AZO/TiO2 Core/Shell Nanocone Array with Uniformly Dispersed Au NPs for Enhancing Photoelectrochemical Water Splitting
Authors: Mi Yan , Wen Liaoyong , Xu Rui , Wang Zhijie , Cao Dawei , Fang Yaoguo , Lei Yong
Published: November 2015

Constructing core/shell nanostructures with optimal structure and composition could maximize the solar light utilization. Here, using an Al nanocone array as a substrate, a well‐defined regular array of AZO/TiO2 core/shell nanocones with uniformly dispersed Au nanoparticles (AZO/TiO2/Au NCA) is successfully realized through three sequential steps of atomic layer deposition, physical vapor deposition, and annealing processes. By tuning the structural and compositional parameters, the advantages of light trapping and short carrier diffusion from the core/shell nanocone array, as well as the surface plasmon resonance and catalytic effects from the Au nanoparticles can be maximally utilized. Accordingly, a remarkable photoelectrochemical (PEC) performance can be acquired and the photocurrent density of the AZO/TiO2/Au NCA electrode reaches up to 1.1 mA cm−2 at 1.23 V, versus reversible hydrogen electrode (RHE) under simulated sunlight illumination, which is five times that of a flat AZO/TiO2 electrode (0.22 mA cm−2). Moreover, the photoconversion of the AZO/TiO2/Au NCA electrode approaches 0.73% at 0.21 V versus RHE, which is one of the highest values with the lowest applied bias ever reported in Au/TiO2 PEC composites. These results demonstrate a feasible route toward the scalable fabrication of well‐modulated core/shell nanostructures and can be easily applied to other metal/semiconductor composites for high‐performance PEC.
Correlation Between Microstructure and Na Storage Behavior in Hard Carbon
Authors: Zhang Biao , Ghimbeu Camélia Matei , Laberty Christel , Vix‐Guterl Cathie , Tarascon Jean‐Marie
Published: November 2015

Hard carbons are considered among the most promising anode materials for Na‐ion batteries. Understanding their structure is of great importance for optimizing their Na storage capabilities and therefore achieving high performance. Herein, carbon nanofibers (CNFs) are prepared by electrospinning and their microstructure, texture, and surface functionality are tailored through carbonization at various temperatures ranging from 650 to 2800 °C. Stepwise carbonization gradually removes the heteroatoms and increases the graphitization degree, enabling us to monitor the corresponding electrochemical performance for establishing a correlation between the CNFs characteristics and Na storage behavior. Outstandingly, it is found that for CNFs carbonized at above 2000 °C, a single voltage Na uptake plateau at ≈0.1 V with a capacity of ≈200 mAh g‐1. This specific performance may be nested in the higher degree of graphitization, lower active surface area, and different porous texture of the CNFs at such temperatures. It is demonstrated via the assembly of a CNF/Na2Fe2(SO4)3 cell the benefit of such CNFs electrode for enhancing the energy density of full Na‐ion cells. This finding sheds new insights in the quest for high performance carbon based anode materials.
Thalassemia 2016: Modern medicine battles an ancient disease
Authors: Rund Deborah
Published: November 2015

Thalassemia was first clinically described nearly a century ago and treatment of this widespread genetic disease has greatly advanced during this period. DNA‐based diagnosis elucidated the molecular basis of the disease and clarified the variable clinical picture. It also paved the way for modern methods of carrier identification and prevention via DNA‐based prenatal diagnosis. Every aspect of supportive care, including safer blood supply, more regular transfusions, specific monitoring of iron overload, parenteral and oral chelation, and other therapies, has prolonged life and improved the quality of life of these patients. Significant advances have also been made in allogenic bone marrow transplantation, the only curative therapy. Recently, there has been a rejuvenated interest in studying thalassemia at the basic science level, leading to the discovery of previously unknown mechanisms leading to anemia and enabling the development of novel therapies. These will potentially improve the treatment of, and possibly cure the disease. Pathways involving activin receptors, heat shock proteins, JAK2 inhibitors and macrophage targeted therapy, among others, are being studied or are currently in clinical trials for treating thalassemia. Novel types of genetic therapies are in use or under investigation. In addition to the challenges of treating each individual patient, the longer survival of thalassemia patients has raised considerations regarding worldwide control of thalassemia, since prevention is not universally implemented. This review will trace a number of the original medical milestones of thalassemia diagnosis and treatment, as well as some of the most recent developments which may lead to innovative therapeutic modalities. Am. J. Hematol. 91:15–21, 2016. © 2015 Wiley Periodicals, Inc.
Acylsilanes in Iridium‐Catalyzed Directed Amidation Reactions and Formation of Heterocycles via Siloxycarbenes
Authors: Becker Peter , Pirwerdjan Ramona , Bolm Carsten
Published: November 2015

Exposing ortho‐amido aroylsilanes to visible light or heat leads to cyclization reactions that provide N‐heterocyclic compounds via siloxycarbenes as key intermediates. The previously unreported starting materials have been prepared by directed amidations of aromatic acylsilanes in the presence of an iridium catalyst followed by N‐alkylation.
Fluorescent microspheres of poly(ethylene glycol)–poly(lactic acid)–fluorescein copolymers synthesized by Ugi four‐component condensation
Authors: Icart Luis P. , Fernandes Edson , Agüero Lissette , Ramón Jose , Zaldivar Dionisio , Dias Marcos L.
Published: November 2015

Microparticles formed by poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) diblock copolymers containing fluorescein grafted to the polymer chain were synthesized by a Ugi four‐component condensation (UFCC) reaction. To synthesize these copolymers, lactide was first polymerized by a ring‐opening polymerization with alcohol initiators containing functional groups to give carboxyl‐ and aldehyde‐end‐functionalized PLA. Two different fluorescent block copolymers (FCPs) of PEG–PLA conjugated to fluorescein (FCP 1 and FCP 2) were then synthesized by UFCC; they gave yields in the range 65–75%. These copolymers were characterized well according their chemical structures and thermal properties, and we prepared fluorescent microspheres (FMSs) from them with the single emulsion–solvent evaporation method (FMS 1 and FMS 2). A new application of UFCC in the preparation of biomasked drug‐delivery systems is proposed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42994.
Preparation and properties of novel, flexible, lead‐free X‐ray‐shielding materials containing tungsten and bismuth(III) oxide
Authors: Chai Hao , Tang Xiaobin , Ni Minxuan , Chen Feida , Zhang Yun , Chen Da , Qiu Yunlong
Published: November 2015

Novel, flexible, lead‐free X‐ray‐shielding composites were prepared with a high‐functional methyl vinyl silicone rubber (VMQ) matrix with W and Bi2O3 as filler materials. To verify the advanced properties of the lead‐free material, composites with the same mass fraction of PbO were compared. With the X‐ray energy ranging from 48 to 185 keV, the W/Bi2O3/VMQ composites exhibited higher X‐ray‐shielding properties. As the filler volume fraction decreased, the tensile strength, elongation, tear strength, and flexibility of the W/Bi2O3/VMQ composites increased. The Shore hardness of the W/Bi2O3/VMQ composites had a maximum value of 46.6 HA and was still very flexible. With decreasing filler volume fraction, the water‐vapor transmission performances of the W/Bi2O3/VMQ composites increased, and the W/Bi2O3/VMQ composites also showed better water‐vapor permeability. The heat‐transfer properties of the W/Bi2O3/VMQ composites increased with increasing W content, and when the W content exceeded 70 wt %, the thermal conductivity of the W/Bi2O3/VMQ material was about 70.45% higher than that of the PbO/VMQ composite. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43012.
Effect of the melting temperature on the crystallization behavior of a poly(l‐lactide)/poly(d‐lactide) equimolar mixture
Authors: Yin Yongai , Song Yan , Xiong Zujiang , Zhang Xiuqin , de Vos Sicco , Wang Ruyin , Joziasse Cornelis A. P. , Liu Guoming , Wang Dujin
Published: November 2015

The effect of the final melting temperature (Tf) on the crystallization of poly(l‐lactide) (PLLA)/poly(d‐lactide) (PDLA) was studied via a combination of differential scanning calorimetry, wide‐angle X‐ray scattering, polarized optical microscopy, and Fourier transform infrared (FTIR) spectroscopy. We observed that a residual stereocomplex (SC) crystal induced the formation of SC crystals during cooling from a Tf (230°C) just above the melting peak of the SC crystals. On cooling from a Tf (240°C) just above the endset temperature of SC crystal melting [Tm(S)(E)], the possible order structure and the strong interchain interaction promoted the preferential crystallization of SC crystals; this enhanced the formation of α crystals. During cooling from a Tf (≥250°C) far above Tm(S)(E), the crystallization peaks of α and SC crystals converged. The FTIR results indicated that the residual SC crystals, possible ordered structure, and interchain interactions in the melt might have been the key factors for the different crystallization of PLLA/PDLA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43015.
Molecular basis of the structural stability of hemochromatosis factor E: A combined molecular dynamic simulation and GdmCl‐induced denaturation study
Authors: Khan Parvez , Parkash Amresh , Islam Asimul , Ahmad Faizan , Hassan Md. Imtaiyaz
Published: November 2015

Hemochromatosis factor E (HFE) is a member of class I MHC family and plays a significant role in the iron homeostasis. Denaturation of HFE induced by guanidinium chloride (GdmCl) was measured by monitoring changes in [θ]222 (mean residue ellipticity at 222 nm), intrinsic fluorescence emission intensity at 346 nm (F346) and the difference absorption coefficient at 287 nm (Δε287) at pH 8.0 and 25°C. Coincidence of denaturation curves of these optical properties suggests that GdmCl‐induced denaturation (native (N) state ↔ denatured (D) state) is a two‐state process. The GdmCl‐induced denaturation was found reversible in the entire concentration range of the denaturant. All denaturation curves were analyzed for
, Gibbs free energy change associated with the denaturation equilibrium (N state ↔ D state) in the absence of GdmCl, which is a measure of HFE stability. We further performed molecular dynamics simulation for 40 ns to see the effect of GdmCl on the structural stability of HFE. A well defined correlation was established between in vitro and in silico studies. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 133–142, 2016.
The attitudes of medical students in Europe toward the clinical importance of embryology
Authors: Moxham Bernard John , Emmanouil‐Nikoloussi Elpida , Standley Henrietta , Brenner Erich , Plaisant Odile , Brichova Hana , Pais Diogo , Stabile Isobel , Borg Jordy , Chirculescu Andy
Published: November 2015

Although there have been many studies reporting the attitudes of medical students to the clinical importance of gross anatomy, little is known about their opinions concerning the clinical importance of embryology. Using Thurstone and Chave methods to assess attitudes, nearly 1,600 medical students across Europe in the early stages of their training provided responses to a survey that tested the hypothesis that they do not regard embryology as highly clinically relevant. Indeed, we further proposed that student attitudes to gross anatomy are much more positive than those toward embryology. Our findings show that our hypotheses hold, regardless of the university and country surveyed and regardless of the teaching methods employed for embryology. Clearly, embryology has a significant part to play in medical education in terms of understanding prenatal life, of appreciating how the organization of the mature human body has developed, and of providing essential information for general medical practice, obstetrics and pediatrics, and teratology. However, while newly recruited medical students understand the importance of gross anatomy in the development of professional competence, understanding the importance of embryology requires teachers, medical educationalists, and devisors of medical curricula to pay special attention to informing students of the significant role played by embryology in attaining clinical competence and achieving the knowledge and understanding of the biomedical sciences that underpins becoming a learned member of a health care profession. Clin. Anat. 29:144–150, 2016. © 2015 Wiley Periodicals, Inc.
Machinima: Extending brand reach
Authors: Harwood Tracy , Garry Tony , Uwins Mike
Published: November 2015

The paper presents findings of an empirical qualitative investigation into the role of machinima (machine‐cinema) in extending the brand reach of game developers' market propositions, drawing on participation, co‐creation and immaterial labour literature. Machinima is a contemporary Internet cultural phenomenon, whereby firms' ‘super’ customers create original works from game assets beyond that of merely gameplay. Interestingly, firms' marketing strategies are evidently focussed on traditional channels with apparently little emphasis given to Internet born cultures such as machinima, which now has massive global following. Thus, the resultant user‐generated content, which may be subsequently adapted and further distributed by other customers, is harnessed by firms, effectively exploiting the prowess of the community of games players to market their endeavours as advertising and product development. Copyright © 2015 John Wiley & Sons, Ltd.
Chemical Synthesis of GM2 Glycans, Bioconjugation with Bacteriophage Qβ, and the Induction of Anticancer Antibodies
Authors: Yin Zhaojun , Dulaney Steven , McKay Craig S. , Baniel Claire , Kaczanowska Katarzyna , Ramadan Sherif , Finn M. G. , Huang Xuefei
Published: November 2015

The development of carbohydrate‐based antitumor vaccines is an attractive approach towards tumor prevention and treatment. Herein, we focused on the ganglioside GM2 tumor‐associated carbohydrate antigen (TACA), which is overexpressed in a wide range of tumor cells. GM2 was synthesized chemically and conjugated with a virus‐like particle derived from bacteriophage Qβ. Although the copper‐catalyzed azide–alkyne cycloaddition reaction efficiently introduced 237 copies of GM2 per Qβ, this construct failed to induce significant amounts of anti‐GM2 antibodies compared to the Qβ control. In contrast, GM2 immobilized on Qβ through a thiourea linker elicited high titers of IgG antibodies that recognized GM2‐positive tumor cells and effectively induced cell lysis through complement‐mediated cytotoxicity. Thus, bacteriophage Qβ is a suitable platform to boost antibody responses towards GM2, a representative member of an important class of TACA: the ganglioside.
Low‐Lanthanide‐Content CeO2/MgO Catalysts with Outstandingly Stable Oxygen Storage Capacities: An In‐Depth Structural Characterization by Advanced STEM Techniques
Authors: Tinoco Miguel , Sanchez Juan J. , Yeste María P. , Lopez‐Haro Miguel , Trasobares Susana , Hungria Ana B. , Bayle‐Guillemaud Pascale , Blanco Ginesa , Pintado José M. , Calvino José J.
Published: November 2015

A novel CeO2/MgO catalyst with low ceria loading has been synthesized. This catalyst showed unique redox properties compared with conventional high and low surface area CeO2. Advanced (scanning) transmission electron microscopy techniques revealed the presence of a variety of highly dispersed ceria nanostructures: isolated CeOx entities, CeO2 clusters, as well as fairly small (<5 nm) CeO2 nanoparticles. More interestingly, this CeO2/MgO catalyst showed outstanding stability in its redox response against high temperature aging treatments. Thus, after reduction in hydrogen at 950 °C and further oxidation at 500 °C, CeO2 reduction effects took still place at low temperatures, and no significant loss of oxygen storage capacity (OSC) was detected. Unique ceria‐bilayer nanostructures were found and characterized in the aged catalyst. Their peculiar structural and chemical properties seem to be responsible for the large improvement observed in the stability of the redox response.
Site Isolation Leads to Stable Photocatalytic Reduction of CO2 over a Rhenium‐Based Catalyst
Authors: Liang Weibin , Church Tamara L. , Zheng Sisi , Zhou Chenlai , Haynes Brian S. , D'Alessandro Deanna M.
Published: November 2015

A porous organic polymer incorporating [(α‐diimine)Re(CO)3Cl] moieties was produced and tested in the photocatalytic reduction of CO2, with NEt3 as a sacrificial donor. The catalyst generated both H2 and CO, although the Re moiety was not required for H2 generation. After an induction period, the Re‐containing porous organic polymer produced CO at a stable rate, unless soluble [(bpy)Re(CO)3Cl] (bpy=2,2′‐bipyridine) was added. This provides the strongest evidence to date that [(α‐diimine)Re(CO)3Cl] catalysts for photocatalytic CO2 reduction decompose through a bimetallic pathway.
A Mononuclear Uranium(IV) Single‐Molecule Magnet with an Azobenzene Radical Ligand
Authors: Antunes Maria A. , Coutinho Joana T. , Santos Isabel C. , Marçalo Joaquim , Almeida Manuel , Baldoví José J. , Pereira Laura C. J. , Gaita‐Ariño Alejandro , Coronado Eugenio
Published: November 2015

A tetravalent uranium compound with a radical azobenzene ligand, namely, [{(SiMe2NPh)3‐tacn}UIV(η2‐N2Ph2.)] (2), was obtained by one‐electron reduction of azobenzene by the trivalent uranium compound [UIII{(SiMe2NPh)3‐tacn}] (1). Compound 2 was characterized by single‐crystal X‐ray diffraction and 1H NMR, IR, and UV/Vis/NIR spectroscopy. The magnetic properties of 2 and precursor 1 were studied by static magnetization and ac susceptibility measurements, which for the former revealed single‐molecule magnet behaviour for the first time in a mononuclear UIV compound, whereas trivalent uranium compound 1 does not exhibit slow relaxation of the magnetization at low temperatures. A first approximation to the magnetic behaviour of these compounds was attempted by combining an effective electrostatic model with a phenomenological approach using the full single‐ion Hamiltonian.