bluuebunny/crossref_metadata_2025 huggingface dataset:
MAVEN observations of solar wind hydrogen deposition in the atmosphere of Mars
Authors: Halekas J. S. , Lillis R. J. , Mitchell D. L. , Cravens T. E. , Mazelle C. , Connerney J. E. P. , Espley J. R. , Mahaffy P. R. , Benna M. , Jakosky B. M. , Luhmann J. G. , McFadden J. P. , Larson D. E. , Harada Y. , Ruhunusiri S.
Published: November 2015

Mars Atmosphere and Volatile EvolutioN mission (MAVEN) observes a tenuous but ubiquitous flux of protons with the same energy as the solar wind in the Martian atmosphere. During high flux intervals, we observe a corresponding negative hydrogen population. The correlation between penetrating and solar wind fluxes, the constant energy, and the lack of a corresponding charged population at intermediate altitudes implicate products of hydrogen energetic neutral atoms from charge exchange between the upstream solar wind and the exosphere. These atoms, previously observed in neutral form, penetrate the magnetosphere unaffected by electromagnetic fields (retaining the solar wind velocity), and some fraction reconvert to charged form through collisions with the atmosphere. MAVEN characterizes the energy and angular distributions of both penetrating and backscattered particles, potentially providing information about the solar wind, the hydrogen corona, and collisional interactions in the atmosphere. The accretion of solar wind hydrogen may provide an important source term to the Martian atmosphere over the planet's history.
The first in situ electron temperature and density measurements of the Martian nightside ionosphere
Authors: Fowler C. M. , Andersson L. , Ergun R. E. , Morooka M. , Delory G. , Andrews D. J. , Lillis Robert J. , McEnulty T. , Weber T. D. , Chamandy T. M. , Eriksson A. I. , Mitchell D. L. , Mazelle C. , Jakosky B. M.
Published: November 2015

The first in situ nightside electron density and temperature profiles at Mars are presented as functions of altitude and local time (LT) from the Langmuir Probe and Waves (LPW) instrument on board the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission spacecraft. LPW is able to measure densities as low as ∼100 
, a factor of up to 10 or greater improvement over previous measurements. Above 200 km, near‐vertical density profiles of a few hundred cubic centimeters were observed for almost all nightside LT, with the lowest densities and highest temperatures observed postmidnight. Density peaks of a few thousand cubic centimeters were observed below 200 km at all nightside LT. The lowest temperatures were observed below 180 km and approach the neutral atmospheric temperature. One‐dimensional modeling demonstrates that precipitating electrons were able to sustain the observed nightside ionospheric densities below 200 km.
New observations of molecular nitrogen in the Martian upper atmosphere by IUVS on MAVEN
Authors: Stevens M. H. , Evans J. S. , Schneider N. M. , Stewart A. I. F. , Deighan J. , Jain S. K. , Crismani M. , Stiepen A. , Chaffin M. S. , McClintock W. E. , Holsclaw G. M. , Lefèvre F. , Lo D. Y. , Clarke J. T. , Montmessin F. , Bougher S. W. , Jakosky B. M.
Published: November 2015

We identify molecular nitrogen (N2) emissions in the Martian upper atmosphere using the Imaging Ultraviolet Spectrograph (IUVS) on NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. We report the first observations of the N2 Lyman‐Birge‐Hopfield (LBH) bands at Mars and confirm the tentative identification of the N2 Vegard‐Kaplan (VK) bands. We retrieve N2 density profiles from the VK limb emissions and compare calculated limb radiances between 90 and 210 km against both observations and predictions from a Mars general circulation model (GCM). Contrary to earlier analyses using other satellite data, we find that N2 abundances exceed GCM results by about a factor of 2 at 130 km but are in agreement at 150 km. The analysis and interpretation are enabled by a linear regression method used to extract components of UV spectra from IUVS limb observations.
Structure and composition of the neutral upper atmosphere of Mars from the MAVEN NGIMS investigation
Authors: Mahaffy P. R. , Benna M. , Elrod M. , Yelle R. V. , Bougher S. W. , Stone S. W. , Jakosky B. M.
Published: November 2015

The Mars Atmosphere and Volatile EvolutioN (MAVEN) Neutral Gas and Ion Mass Spectrometer (NGIMS) provides sensitive detections of neutral gas and ambient ion composition. NGIMS measurements of nine atomic and molecular neutral species, and their variation with altitude, latitude, and solar zenith angle are reported over several months of operation of the MAVEN mission. Sampling NGIMS signals from multiple neutral species every several seconds reveals persistent and unexpectedly large amplitude density structures. The scale height temperatures are mapped over the course of the first few months of the mission from high down to midlatitudes. NGIMS measurements near the homopause of 40Ar/N2 ratios agree with those reported by the Sample Analysis at Mars investigation and allow the altitude of the homopause for the most abundant gases to be established.
Study of the Martian cold oxygen corona from the O I 130.4 nm by IUVS/MAVEN
Authors: Chaufray J. Y. , Deighan J. , Chaffin M. S. , Schneider N. M. , McClintock W. E. , Stewart A. I. F. , Jain S. K. , Crismani M. , Stiepen A. , Holsclaw G. M. , Clarke J. T. , Montmessin F. , Eparvier F. G. , Thiemann E. M. B. , Chamberlin P. C. , Jakosky B. M.
Published: November 2015

First observations of the O I 130.4 nm resonant line performed by the Imaging Ultraviolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile EvolutioN mission (MAVEN) are presented in this paper. This emission line is observed during the different orbit phases of MAVEN. The atomic oxygen density and the temperature at 200 km are retrieved from an automatic pipeline using a radiative transfer model for resonant scattering lines for a selection of coronal profiles. These selected profiles are representative of the coronal scans done during the first months of the mission (from November 2014 to January 2015). The derived oxygen density and the temperature near the exobase are in the predicted range by the current thermospheric models of Mars for moderate solar activity, and some diurnal variations are observed. However, the absolute calibration of the instrument significantly limits the accuracy of density and temperature results.
MAVEN IUVS observation of the hot oxygen corona at Mars
Authors: Deighan J. , Chaffin M. S. , Chaufray J.‐Y. , Stewart A. I. F. , Schneider N. M. , Jain S. K. , Stiepen A. , Crismani M. , McClintock W. E. , Clarke J. T. , Holsclaw G. M. , Montmessin F. , Eparvier F. G. , Thiemann E. M. B. , Chamberlin P. C. , Jakosky B. M.
Published: November 2015

Observation of the hot oxygen corona at Mars has been an elusive measurement in planetary science. Characterizing this component of the planet's exosphere provides insight into the processes driving loss of oxygen at the current time, which informs understanding of the planet's climatic evolution. The Mars Atmosphere and Volatile EvolutioN (MAVEN) Imaging Ultraviolet Spectrograph (IUVS) instrument is now regularly collecting altitude profiles of the hot oxygen corona as part of its investigation of atmospheric escape from Mars. Observations obtained thus far have been examined and found to display the expected gross structure and variability with EUV forcing anticipated by theory. The quality and quantity of the data set provides valuable constraints for the coronal modeling community.
Time reverse imaging for far‐field tsunami forecasting: 2011 Tohoku earthquake case study
Authors: Hossen M. Jakir , Cummins Phil R. , Dettmer Jan , Baba Toshitaka
Published: November 2015

This paper describes a new method for forecasting far‐field tsunamis by combining aspects of least squares tsunami source inversion (LSQ) with time reverse imaging (TRI). This method has the same source representation as LSQ but uses TRI to estimate initial sea surface displacement. We apply this method to the 2011 Japan tsunami, and the results show that the method produces tsunami waveforms of excellent agreement with observed waveforms at both near‐ and far‐field stations not used in the source estimation. The spatial distribution of cumulative sea surface displacement agrees well with other models obtained in more sophisticated inversions, but resolve source kinematics are not well resolved. The method has potential for application in tsunami warning systems, as it is computationally efficient and can be used to estimate the initial source model by applying precomputed Green's functions in order to provide more accurate and realistic tsunami predictions.
Investigation of coseismic and postseismic processes using in situ measurements of seismic velocity variations in an underground mine
Authors: Olivier G. , Brenguier F. , Campillo M. , Roux P. , Shapiro N. M. , Lynch R.
Published: November 2015

The in situ mechanical response of a rock mass to a sudden dynamic and static stress change is still poorly known. To tackle this question, we conducted an experiment in an underground mine to examine (1) the influence of dynamic and static stress perturbations on seismic velocities, (2) elastic static stress changes, and (3) induced earthquake activity associated with the blast and removal of a portion of hard rock. We accurately (0.01%) measured seismic velocity variations with ambient seismic noise correlations, located aftershock activity, and performed elastic static stress modeling. Overall, we observe that the blast induced a sudden decrease in seismic velocities over the entire studied area, which we interpreted as the damage due to the passing of strong seismic waves. This sudden process is followed by a slow relaxation lasting up to 5 days, while seismic activity returns to its background level after 2 days. In some locations, after the short‐term effects of the blast have subsided, the seismic velocities converge to new baseline levels and permanent changes in seismic velocity become visible. After comparing the spatial pattern of permanent seismic velocity changes with elastic static stress modeling, we infer that the permanent seismic velocity changes are due to the change in the static volumetric stress induced by the removal of a solid portion of rock by the blast. To our knowledge, this is the first observation of noise‐based permanent seismic velocity changes associated with static stress changes.
Changes in the thermosphere and ionosphere of Mars from Viking to MAVEN
Authors: Withers Paul , Vogt Marissa , Mahaffy Paul , Benna Mehdi , Elrod Meredith , Jakosky Bruce
Published: November 2015

We compare Viking and Mars Atmosphere and Volatile EvolutioN mission (MAVEN) Neutral Gas and Ion Mass Spectrometer (NGIMS) observations of the thermosphere and ionosphere of Mars in order to test predictions of large variations in conditions over the solar cycle and with season. Substantial differences exist between the Viking observations at solar minimum and near aphelion and the MAVEN NGIMS observations at moderate solar activity and near perihelion. Differences in the O/CO2 ratio, the O+ ionospheric peak, ion densities at high altitude, and neutral and ion scale heights can be attributed to differences in solar activity and season, but the relative importance of solar activity and season for these differences was not established. Current models do not explain the observed differences in the mixing ratios of N, NO, and O2. These results place new constraints on models of how the thermosphere and ionosphere of Mars vary over the solar cycle and with season.
The relative contribution of orbital forcing and greenhouse gases to the North American deglaciation
Authors: Gregoire Lauren J. , Valdes Paul J. , Payne Antony J.
Published: November 2015

Understanding what drove Northern Hemisphere ice sheet melt during the last deglaciation (21–7 ka) can help constrain how sensitive contemporary ice sheets are to greenhouse gas (GHGs) changes. The roles of orbital forcing and GHGs in the deglaciation have previously been modeled but not yet quantified. Here for the first time we calculate the relative effect of these forcings on the North American deglaciation by driving a dynamical ice sheet model (GLIMMER‐CISM) with a set of unaccelerated transient deglacial simulations with a full primitive equation‐based ocean‐atmosphere general circulation model (FAMOUS). We find that by 9 ka, orbital forcing has caused 50% of the deglaciation, GHG 30%, and the interaction between the two 20%. Orbital forcing starts affecting the ice volume at 19 ka, 2000 years before CO2 starts increasing in our experiments, a delay which partly controls their relative effect.
Seasonal variability of eddy kinetic energy in a global high‐resolution ocean model
Authors: Rieck Jan K. , Böning Claus W. , Greatbatch Richard J. , Scheinert Markus
Published: November 2015

A global ocean model with 1/12° horizontal resolution is used to assess the seasonal cycle of surface eddy kinetic energy (EKE). The model reproduces the salient features of the observed mean surface EKE, including amplitude and phase of its seasonal cycle in most parts of the ocean. In all subtropical gyres of the Pacific and Atlantic, EKE peaks in summer down to a depth of ∼350 m, below which the seasonal cycle is weak. Investigation of the possible driving mechanisms reveals the seasonal changes in the thermal interactions with the atmosphere to be the most likely cause of the summer maximum of EKE. The development of the seasonal thermocline in spring and summer is accompanied by stronger mesoscale variations in the horizontal temperature gradients near the surface which corresponds, by thermal wind balance, to an intensification of mesoscale velocity anomalies toward the surface.
Evidence for long‐lived subduction of an ancient tectonic plate beneath the southern Indian Ocean
Authors: Simmons N. A. , Myers S. C. , Johannesson G. , Matzel E. , Grand S. P.
Published: November 2015

Ancient subducted tectonic plates have been observed in past seismic images of the mantle beneath North America and Eurasia, and it is likely that other ancient slab structures have remained largely hidden, particularly in the seismic‐data‐limited regions beneath the vast oceans in the Southern Hemisphere. Here we present a new global tomographic image, which shows a slab‐like structure beneath the southern Indian Ocean with coherency from the upper mantle to the core‐mantle boundary region—a feature that has never been identified. We postulate that the structure is an ancient tectonic plate that sank into the mantle along an extensive intraoceanic subduction zone that migrated southwestward across the ancient Tethys Ocean in the Mesozoic Era. Slab material still trapped in the transition zone is positioned near the edge of East Gondwana at 140 Ma suggesting that subduction terminated near the margin of the ancient continent prior to breakup and subsequent dispersal of its subcontinents.
Vulnerability of water availability in India due to climate change: A bottom‐up probabilistic Budyko analysis
Authors: Singh Riddhi , Kumar Rohini
Published: November 2015

Quantifying the dependence of future water availability on changing climate is critical for water resources planning and management in water stressed countries like India. However, this remains a challenge as long‐term streamflow data are scarce, and there are significant uncertainties regarding future climate change. We present a bottom‐up probabilistic Budyko framework that estimates the vulnerability of available water to changing climate using three hydroclimatic variables: long‐term precipitation, potential evapotranspiration, and actual evapotranspiration. We assimilate these variables within a probabilistic Budyko framework to derive estimates of water availability and associated uncertainty. We then explore a large range of possible future climates to identify critical climate thresholds and their spatial variation across India. Based on this exploratory analysis, we find that southern India is most susceptible to changing climate with less than 10% decrease in precipitation causing a 25% decrease in water availability.
Hydrogen isotope fractionation and redox‐controlled solution mechanisms in silicate‐COH melt + fluid systems
Authors: Mysen Bjorn
Published: November 2015

The behavior of volatiles in silicate‐COH melts and fluids and hydrogen isotope fractionation between melt and fluid were determined experimentally to advance our understanding of the role of volatiles in magmatic processes. Experiments were conducted in situ while the samples were at the desired temperature and pressure to 825°C and ~1.6 GPa and with variable redox conditions. Under oxidizing conditions, melt and fluid comprised CO2, CO3, HCO3, OH, H2O, and silicate components, whereas under reducing conditions, the species were CH4, H2, H2O, and silicate components. Temperature‐dependent hydrogen isotope exchange among structural entities within coexisting fluids and melts yields ΔH values near 14 and 24 kJ/mol and −5 and −1 kJ/mol under oxidizing and reducing conditions, respectively. This temperature (and probably pressure)‐dependent D/H fractionation is because of interaction between D and H and silicate and C‐bearing species in silicate‐saturated fluids and in COH fluid‐saturated melts. The temperature‐ and pressure‐dependent D/H fractionation factors suggest that partial melts in the presence of COH volatiles in the upper mantle can have δD values 100% or more lighter relative to coexisting silicate‐saturated fluid. This effect is greater under oxidizing than under reducing conditions. It is suggested that δD variations of upper mantle mid‐ocean ridge basalt (MORB) sources, inferred from the δD of MORB magmatic rocks, can be explained by variations in redox conditions during melting. Lower δD values of the MORB magma reflect more reducing conditions in the mantle source.
Reconstruction of a meteotsunami in Lake Erie on 27 May 2012: Roles of atmospheric conditions on hydrodynamic response in enclosed basins
Authors: Anderson Eric J. , Bechle Adam J. , Wu Chin H. , Schwab David J. , Mann Greg E. , Lombardy Kirk A.
Published: November 2015

On 27 May 2012, atmospheric conditions gave rise to two convective systems that generated a series of waves in the meteotsunami band on Lake Erie. The resulting waves swept three swimmers a 0.5 mi offshore, inundated a marina, and may have led to a capsized boat along the southern shoreline. Analysis of radial velocities from a nearby radar tower in combination with coastal meteorological observation indicates that the convective systems produced a series of outflow bands that were the likely atmospheric cause of the meteotsunami. In order to explain the processes that led to meteotsunami generation, we model the hydrodynamic response to three meteorological forcing scenarios: (i) the reconstructed atmospheric disturbance from radar analysis, (ii) simulated conditions from a high‐resolution weather model, and (iii) interpolated meteorological conditions from the NOAA Great Lakes Coastal Forecasting System. The results reveal that the convective systems generated a series of waves incident to the southern shore of the lake that reflected toward the northern shoreline and reflected again to the southern shore, resulting in spatial wave focusing and edge wave formation that combined to impact recreational users near Cleveland, OH. This study illustrates the effects of meteotsunami development in an enclosed basin, including wave reflection, focusing, and edge wave formation as well as temporal lags between the causative atmospheric conditions and arrival of dangerous wave conditions. As a result, the ability to detect these extreme storms and predict the hydrodynamic response is crucial to reducing risk and building resilient coastal communities.
CO2 sink/source characteristics in the tropical Indonesian seas
Authors: Kartadikaria A. R. , Watanabe A. , Nadaoka K. , Adi N. S. , Prayitno H. B. , Soemorumekso S. , Muchtar M. , Triyulianti I. , Setiawan A. , Suratno S. , Khasanah E. N.
Published: November 2015

Two distinct CO2 sink/source characteristics are found in the tropical Indonesian seas from the compilation of observed data for the period 1984–2013. The western region persistently emits CO2 to the atmosphere, whereas the eastern region is dynamic and acts either as a small source or sink of CO2 to the atmosphere, depending on sites. The segregation is proximal to the Makassar Strait, which is located over the continental shelf and is one of the main routes of the Indonesian Throughflow (ITF). Lower salinity and higher silicate were found in the western region, suggesting a terrestrial influence in this area. Temperature has a limited influence in controlling different CO2 sink/source characteristics in the west and east. However, an SST change of −2.0°C during La Niña events effectively reduces the pCO2 difference between the atmosphere and surface seawater by 50% compared to normal year conditions. During La Niña events, higher wind speeds double the CO2 flux from the ocean to the atmosphere compared to that of a normal year. In the continental shelf area where the CO2 sink area was found, data of over 29 years show that the seawater pCO2 increased by 0.6–3.8 μatm yr−1. Overall, the seawater pCO2 of the Indonesian seas is supersaturated relative to the atmosphere by 15.9 ± 8.6 μatm and thus acts as a source of CO2 to the atmosphere.
A comparative assessment of coastal mean dynamic topography in Norway by geodetic and ocean approaches
Authors: Ophaug Vegard , Breili Kristian , Gerlach Christian
Published: November 2015

The ocean's mean dynamic topography (MDT) is the surface representation of ocean circulation. It may be determined by the ocean approach, using numerical ocean circulation models, or by the geodetic approach, where MDT is the height of the mean sea surface (MSS), or mean sea level (MSL), above the geoid. Using new geoid models, geodetic MDT profiles based on tide gauges, dedicated coastal altimetry products, and conventional altimetry are compared with six ocean MDT estimates independent of geodetic data. Emphasis is put on the determination of high‐resolution geoid models, combining ESA's fifth release (R5) of GOCE satellite‐only global gravity models (GGMs) with a regional geoid model for Norway by a filtering technique. Differences between MDT profiles along the Norwegian coast together with Taylor diagrams confirm that geodetic and ocean MDTs agree on the ∼3–7 cm level at the tide gauges, and on the ∼5–11 cm level at the altimetry sites. Some geodetic MDTs correlate more with the best‐performing ocean MDT than do other ocean MDTs, suggesting a convergence of the methods. While the GOCE R5 geoids are shown to be more accurate over land, they do not necessarily show the best agreement over the ocean. Pointwise monomission altimetry products give results comparable with the multimission DTU13MSS grid on the ∼5 cm level. However, dedicated coastal altimetry products generally do not offer an improvement over conventional altimetry along the Norwegian coast.
Cenozoic extension in the Kenya Rift from low‐temperature thermochronology: Links to diachronous spatiotemporal evolution of rifting in East Africa
Authors: Torres Acosta Verónica , Bande Alejandro , Sobel Edward R. , Parra Mauricio , Schildgen Taylor F. , Stuart Finlay , Strecker Manfred R.
Published: November 2015

The cooling history of rift shoulders and the subsidence history of rift basins are cornerstones for reconstructing the morphotectonic evolution of extensional geodynamic provinces, assessing their role in paleoenvironmental changes and evaluating the resource potential of their basin fills. Our apatite fission track and zircon (U‐Th)/He data from the Samburu Hills and the Elgeyo Escarpment in the northern and central sectors of the Kenya Rift indicate a broadly consistent thermal evolution of both regions. Results of thermal modeling support a three‐phased thermal history since the early Paleocene. The first phase (~65–50 Ma) was characterized by rapid cooling of the rift shoulders and may be coeval with faulting and sedimentation in the Anza Rift basin, now located in the subsurface of the Turkana depression and areas to the east in northern Kenya. In the second phase, very slow cooling or slight reheating occurred between ~45 and 15 Ma as a result of either stable surface conditions, very slow exhumation, or subsidence. The third phase comprised renewed rapid cooling starting at ~15 Ma. This final cooling represents the most recent stage of rifting, which followed widespread flood‐phonolite emplacement and has shaped the present‐day landscape through rift shoulder uplift, faulting, basin filling, protracted volcanism, and erosion. When compared with thermochronologic and geologic data from other sectors of the East African Rift System, extension appears to be diachronous, spatially disparate, and partly overlapping, likely driven by interactions between mantle‐driven processes and crustal heterogeneities, rather than the previously suggested north–south migrating influence of a mantle plume.
Hydrological response to changing climate conditions: Spatial streamflow variability in the boreal region
Authors: Teutschbein C. , Grabs T. , Karlsen R. H. , Laudon H. , Bishop K.
Published: November 2015

In this paper we combined a multimodel ensemble based on 15 regional climate models with a multicatchment approach to explore the hydrologic sensitivity of 14 neighboring and rather similar catchments to changing climate conditions. Current (1982–2010) and future (2062–2090) streamflow was simulated with the HBV model. A diagnostic approach was used, which considered major behavioral catchment functions by using hydrologically relevant signatures related to overall water balance, flow duration curves and hydrograph attributes. Projected increases in temperature and precipitation resulted in increased total available streamflow, with lower spring and summer flows, but substantially higher winter streamflow. Furthermore, significant changes in flow durations with lower chances of both high and low flows can be expected in boreal Sweden in the future. This overall trend in projected streamflow pattern changes was comparable among the analyzed catchments but the magnitude of change differed considerably. This suggests that catchments belonging to the same region can show distinctly different degrees of hydrological responses to the same external climate change signal. We reason that differences in spatially distributed physical catchment properties within catchments are not only of great importance for current streamflow behavior, but also play a major role in the sensitivity of catchments to changing climate conditions.
Nonvolatile Floating‐Gate Memories Based on Stacked Black Phosphorus–Boron Nitride–MoS2 Heterostructures
Authors: Li Dong , Wang Xiaojuan , Zhang Qichong , Zou Liping , Xu Xiangfan , Zhang Zengxing
Published: November 2015

Research on van der Waals heterostructures based on stacked 2D atomic crystals is intense due to their prominent properties and potential applications for flexible transparent electronics and optoelectronics. Here, nonvolatile memory devices based on floating‐gate field‐effect transistors that are stacked with 2D materials are reported, where few‐layer black phosphorus acts as channel layer, hexagonal boron nitride as tunnel barrier layer, and MoS2 as charge trapping layer. Because of the ambipolar behavior of black phosphorus, electrons and holes can be stored in the MoS2 charge trapping layer. The heterostructures exhibit remarkable erase/program ratio and endurance performance, and can be developed for high‐performance type‐switching memories and reconfigurable inverter logic circuits, indicating that it is promising for application in memory devices completely based on 2D atomic crystals.
Performance of a medical oxygen concentrator using rapid pressure swing adsorption process: Effect of feed air pressure
Authors: Vemula Rama Rao , Kothare Mayuresh V. , Sircar Shivaji
Published: November 2015

The effects of feed air pressure on the steady‐state performance of a medical oxygen concentrator (MOC) were experimentally evaluated using a novel design of a MOC unit which produced a continuous stream of ∼90% O2 employing a rapid pressure swing adsorption (RPSA) process scheme. Dry, CO2 free air containing ∼1% Ar at different feed gas pressures was used in the tests in conjunction with a commercial sample of LiLSX zeolite as the N2 selective adsorbent in the process. The bed size factor (BSF) can be systematically reduced by increasing the feed air pressure for any given total cycle time. The effect of feed air pressure on the oxygen recovery (R) is, however, more complex; it increases with increasing feed pressure only at longer cycle times while the effect is marginal at shorter cycle times. The BSF cannot be indefinitely reduced by lowering total process cycle time at any pressure—a minimum is exhibited in the BSF‐cycle time plot. The minimum value of the BSF decreases as the feed pressure is increased. The cycle time for the minimum BSF is, however, not significantly altered by the feed pressure in the data range of this work. © 2015 American Institute of Chemical Engineers AIChE J, 62: 1212–1215, 2016
Diastereoselective Synthesis of Macrocyclic Spiro and Dispiro‐1,4‐dithianes, ‐1,4‐oxathianes, and ‐1,4‐dithiepanes through Intramolecular Sulfonium Ylides
Authors: Muthusamy Sengodagounder , Selvaraj Karuppu , Suresh Eringathodi
Published: November 2015

The synthesis of functionalized C2‐symmetric as well as unsymmetrical macrocyclic spiro and dispiro‐1,4‐dithianes, ‐1,4‐oxathianes, and 1,4‐dithiepanes was achieved in a highly diastereoselective manner from the reactions of thiol‐protected cyclic and acyclic diazocarbonyl compounds in the presence of a rhodium(II) acetate dimer catalyst at room temperature. These macrocyclic compounds were obtained by the formation of 9‐ to 13‐membered intramolecular sulfonium ylides followed by a Stevens rearrangement.
An informative prior probability distribution of the gompertz parameters for bayesian approaches in paleodemography
Authors: Sasaki Tomohiko , Kondo Osamu
Published: November 2015

Objectives

In paleodemography, the Bayesian approach has been suggested to provide an effective means by which mortality profiles of past populations can be adequately estimated, and thus avoid problems of “age‐mimicry” inherent in conventional approaches. In this study, we propose an application of the Gompertz model using an “informative” prior probability distribution by revising a recent example of the Bayesian approach based on an “uninformative” distribution.

Methods

Life‐table data of 134 human populations including those of contemporary hunter‐gatherers were used to determine the Gompertz parameters of each population. In each population, we used both raw life‐table data and the Gompertz parameters to calculate some demographic values such as the mean life‐span, to confirm representativeness of the model. Then, the correlation between the two Gompertz parameters (the Strehler–Mildvan correlation) was re‐established. We incorporated the correlation into the Bayesian approach as an “informative” prior probability distribution, and tested its effectiveness using simulated data.

Results

Our analyses showed that the mean life‐span (≥ age 15) and the proportion of living persons aging over 45 were well‐reproduced by the Gompertz model. The simulation showed that using the correlation as an informative prior provides a narrower estimation range in the Bayesian approach than does the uninformative prior.

Conclusions

The Gompertz model can be assumed to accurately estimate the mean life‐span and/or the proportion of old people in a population. We suggest that the Strehler–Mildvan correlation can be used as a useful constraint in demographic reconstructions of past human populations. Am J Phys Anthropol 159:523–533, 2016. © 2015 Wiley Periodicals, Inc.
Neuromyelitis optica: Evaluation of 871 attacks and 1,153 treatment courses
Authors: Kleiter Ingo , Gahlen Anna , Borisow Nadja , Fischer Katrin , Wernecke Klaus‐Dieter , Wegner Brigitte , Hellwig Kerstin , Pache Florence , Ruprecht Klemens , Havla Joachim , Krumbholz Markus , Kümpfel Tania , Aktas Orhan , Hartung Hans‐Peter , Ringelstein Marius , Geis Christian , Kleinschnitz Christoph , Berthele Achim , Hemmer Bernhard , Angstwurm Klemens , Stellmann Jan‐Patrick , Schuster Simon , Stangel Martin , Lauda Florian , Tumani Hayrettin , Mayer Christoph , Zeltner Lena , Ziemann Ulf , Linker Ralf , Schwab Matthias , Marziniak Martin , Then Bergh Florian , Hofstadt‐van Oy Ulrich , Neuhaus Oliver , Winkelmann Alexander , Marouf Wael , Faiss Jürgen , Wildemann Brigitte , Paul Friedemann , Jarius Sven , Trebst Corinna ,   on behalf of the Neuromyelitis Optica Study Group
Published: November 2015

Objective

Neuromyelitis optica (NMO) attacks often are severe, are difficult to treat, and leave residual deficits. Here, we analyzed the frequency, sequence, and efficacy of therapies used for NMO attacks.

Methods

A retrospective review was made of patient records to assess demographic/diagnostic data, attack characteristics, therapies, and the short‐term remission status (complete remission [CR], partial remission [PR], no remission [NR]). Inclusion criteria were NMO according to Wingerchuk's 2006 criteria or aquaporin‐4 antibody–positive NMO spectrum disorder (NMOSD). Remission status was analyzed with generalized estimating equations (GEEs), a patient‐based statistical approach.

Results

A total of 871 attacks in 185 patients (142 NMO/43 NMOSD, 82% female) were analyzed. The 1,153 treatment courses comprised high‐dose intravenous steroids (HD‐S; n = 810), plasma exchange (PE; n = 192), immunoadsorption (IA; n = 38), other (n = 80), and unknown (n = 33) therapies. The first treatment course led to CR in 19.1%, PR in 64.5%, and NR in 16.4% of attacks. Second, third, fourth, and fifth treatment courses were given in 28.2%, 7.1%, 1.4%, and 0.5% of attacks, respectively. This escalation of attack therapy significantly improved outcome (p < 0.001, Bowker test). Remission rates were higher for isolated optic neuritis versus isolated myelitis (p < 0.001), and for unilateral versus bilateral optic neuritis (p = 0.020). Isolated myelitis responded better to PE/IA than to HD‐S as first treatment course (p = 0.037). Predictors of CR in multivariate GEE analysis were age (odds ratio [OR] = 0.97, p = 0.011), presence of myelitis (OR = 0.38, p = 0.002), CR from previous attack (OR = 6.85, p < 0.001), and first‐line PE/IA versus HD‐S (OR = 4.38, p = 0.006).

Interpretation

Particularly myelitis and bilateral optic neuritis have poor remission rates. Escalation of attack therapy improves outcome. PE/IA may increase recovery in isolated myelitis. Ann Neurol 2016;79:206–216
Cyclisierung von Pyrenoligomeren: Cyclohexa‐1,3‐pyrenylen
Authors: Lorbach Dominik , Keerthi Ashok , Figueira‐Duarte Teresa Marina , Baumgarten Martin , Wagner Manfred , Müllen Klaus
Published: November 2015

Die Synthese des Makrocyclus Cyclohexa‐1,3‐pyrenylen über sechs Schritte ausgehend von Pyren wird beschrieben. Der nicht aggregierende und stark verdrillte Makrocyclus ist ein blau emittierendes Material. Die Cyclodehydrierung bietet einen vielversprechenden Syntheseansatz für lochhaltiges Nanographen.
Effect of titanium dioxide (TiO2) distribution and minute amounts of carbon black on the opacity of PVDF based white composite films
Authors: Li Tongbing , Sheng Dekun , Xiong Zhengrong , Gao Xiumei , Ji Fance , Yang Yuming
Published: November 2015

There is a contradiction in making completely opaque and white plastic film with a required high TiO2 filling fraction, which resulted in inefficient pigment utilization and high cost. Two methods were used here to overcome the contradiction. Firstly, TiO2 was grafted with poly(methyl methacrylate) (PMMA) by atom transfer radical polymerization to improve the pigment dispersion in poly(vinylidene) fluoride (PVDF). Secondly, minute amounts of carbon black (CB) were added into the PMMA‐g‐TiO2/PVDF system to enhance opacity and decrease TiO2 fraction. The structure, morphology, and properties of PMMA‐g‐TiO2 hybrid particles and composite films were investigated by FTIR, TEM, TGA, SEM, DMA, covering power meter, and UV/VIS spectrophotometer, etc. It was observed that PMMA‐g‐TiO2 was dispersed uniformly as individual particles in PVDF due to the good compatibility between PMMA and PVDF. Therefore, the opacity of PMMA‐g‐TiO2/PVDF films was markedly higher than unmodified‐TiO2/PVDF ones. Adding minute amounts of CB can significantly increase the opacity of the thin film due to its absorption effect on decreasing light transmittance. The contrast ratio (CR) of the PMMA‐g‐TiO2/PVDF film with 20 μm thickness and 25 vol % TiO2 was 97.67%, lower than the critical CR 98% for a complete opacity, however, the CR of sample with 10 vol % TiO2 was 98.1% as the CB concentration was 2 × 10−4 g/cm3, saved more than 15% TiO2. We proposed that a critical thickness d0 existed for the CB/PMMA‐g‐TiO2/PVDF composite films, under which the light reflectance increased as a function of thickness, otherwise, the reflectance kept constant. Besides, d0 could be decreased by increasing CB concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43064.
Modulating properties of chemically crosslinked PEG hydrogels via physical entrapment of silk fibroin
Authors: Bragg John C. , Kweon Haeyong , Jo YouYoung , Lee Kwang Gill , Lin Chien‐Chi
Published: November 2015

A variety of polymers of synthetic origins (e.g., poly(ethylene glycol) or PEG) and macromolecules derived from natural resources (e.g., silk fibroin or SF) have been explored as the backbone materials for hydrogel crosslinking. Purely synthetic PEG‐based hydrogels are often chemically crosslinked to possess limited degradability, unless labile motifs are designed and integrated into the otherwise non‐degradable macromers. On the other hand, SF produced by Bombyx mori silkworm can be easily formulated into physical hydrogels. These physical gels, however, are less stable than the chemically crosslinked gels. Here, we present a simple strategy to prepare hybrid PEG‐SF hydrogels with chemically crosslinked PEG network and physically entrapped SF. Visible light irradiation initiated rapid thiol‐acrylate gelation to produce a network composed of non‐degradable poly(acrylate‐co‐NVP) chains, hydrolytically labile thioether ester bonds, and interpenetrating SF fibrils. We evaluated the effect of SF entrapment on the crosslinking efficiency and hydrolytic degradation of thiol‐acrylate PEG hydrogels. We further examined the effect of adding soluble SF or sonicated SF (S‐SF) on physical gelation of the hybrid materials. The impacts of SF or S‐SF inclusion on the properties of chemically crosslinked hybrid hydrogels were also studied, including gel points, gel fraction, equilibrium swelling ratio, and mesh size. We also quantified the fraction of SF retention in PEG hydrogels, as well as the influence of remaining SF on moduli and degradation of chemically crosslinked thiol‐acrylate PEG hydrogels. This simple hybrid hydrogel fabrication strategy should be highly useful in future drug delivery and tissue engineering applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43075.
Effect of introducing aib in a designed helical inhibitor of hdm2‐p53 interaction: A molecular dynamics study
Authors: Chattopadhyay Sarbani , Ajani Haresh , Basu Gautam
Published: November 2015

Although p53 is an intrinsically disordered protein, upon binding to Hdm2, a short stretch (residues 19‐25) comprising the binding epitope assumes a helical backbone. Because the allowed conformational space of α‐aminoisobutyric acid (Aib) is restricted to only the helical basin, Aib‐containing helical mimics of p53 (binding epitope) are expected to inhibit interaction between p53 and Hdm2 with a much stronger affinity than the wild type p53 peptide (binding epitope), due to the entropic advantage associated with Aib. However, the IC50 values for the disruption of p53‐Hdm2 interaction by Aib‐p53 peptides and wild type p53 peptide were found to be comparable (J. Peptide Res. 2002, 60:88–94). To understand why incorporation of Aib didn't substantially increase Hdm2 affinity of Aib‐p53 peptides, a series of molecular dynamics simulations were performed. It was found that despite stabilizing a helical backbone in the unbound state, the Aib residues in Aib‐p53 peptide arrested two functionally important side‐chains (F19 and W23) in non‐productive conformations, resulting in relative side‐chain orientations of the binding triad F19‐W23‐L26 incompatible with the bound conformation. Therefore, although a Aib‐induced pre‐formed helical peptide backbone in the unbound state is expected to favor binding, the locked side‐chain orientations of the binding triad in non‐productive modes would disfavor binding. This study shows that when using Aib to design functionally important helical peptides, care must be taken to consider potential interactions between side‐chains of neighboring residues and Aib in the unbound state. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 51–61, 2016.
Computational exploration of a protein receptor binding space with student proposed peptide ligands
Authors: King Matthew D. , Phillips Paul , Turner Matthew W. , Katz Michael , Lew Sarah , Bradburn Sarah , Andersen Tim , McDougal Owen M.
Published: November 2015

Computational molecular docking is a fast and effective in silico method for the analysis of binding between a protein receptor model and a ligand. The visualization and manipulation of protein to ligand binding in three‐dimensional space represents a powerful tool in the biochemistry curriculum to enhance student learning. The DockoMatic tutorial described herein provides a framework by which instructors can guide students through a drug screening exercise. Using receptor models derived from readily available protein crystal structures, docking programs have the ability to predict ligand binding properties, such as preferential binding orientations and binding affinities. The use of computational studies can significantly enhance complimentary wet chemical experimentation by providing insight into the important molecular interactions within the system of interest, as well as guide the design of new candidate ligands based on observed binding motifs and energetics. In this laboratory tutorial, the graphical user interface, DockoMatic, facilitates docking job submissions to the docking engine, AutoDock 4.2. The purpose of this exercise is to successfully dock a 17‐amino acid peptide, α‐conotoxin TxIA, to the acetylcholine binding protein from Aplysia californica‐AChBP to determine the most stable binding configuration. Each student will then propose two specific amino acid substitutions of α‐conotoxin TxIA to enhance peptide binding affinity, create the mutant in DockoMatic, and perform docking calculations to compare their results with the class. Students will also compare intermolecular forces, binding energy, and geometric orientation of their prepared analog to their initial α‐conotoxin TxIA docking results. © 2015 by The International Union of Biochemistry and Molecular Biology, 44:63–67, 2016.
Dioxygen Reduction by Nitrogen‐Rich Mesoporous Carbon bearing Electrodeposited Silver Particles
Authors: Tiwari Aarti , Nagaiah Tharamani C.
Published: November 2015

The electrocatalytic activity of silver particles supported on nitrogen‐containing mesoporous carbon materials (NMC) was studied with a view to dioxygen reduction. Silver particles with controlled size and shape on the NMC were synthesized by a double‐pulse electrodeposition technique. Changing the nucleation and growth potential as well as their growth times resulted in varied morphologies of the electrodeposited silver. The effect of the supporting material itself on the activity was assessed by employing variably pyrolyzed NMC supports. The associated kinetic parameters were evaluated by hydrodynamic measurements in alkaline medium. The dioxygen reduction activity was associated with the available surface area, which was determined by double‐layer capacitance measurements. The stability of the catalyst was tested by chronoamperometric measurements both in the presence and absence of methanol. Elemental components were identified by X‐ray diffraction and X‐ray photoelectron spectroscopy techniques.
Catalyst‐Controlled Selectivity in C−S Bond Formation: Highly Efficient Synthesis of C2‐ and C3‐Sulfonylindoles
Authors: Yang Yong , Li Wanmei , Xia Chengcai , Ying Beibei , Shen Chao , Zhang Pengfei
Published: November 2015

Exploring a potential catalyst system for catalyst‐controlled selectivity in C−S bond formation is a fascinating challenge. Herein, we described two novel and highly efficient methods for the selective synthesis of C2‐ and C3‐sulfonylindoles showing good biological activities by employing iodide and copper catalysts, respectively. Mechanistic studies point to the crucial role of the electronic properties of the sulfonylated intermediates.
Highly Effective Direct Decomposition of Nitric Oxide by Microwave Catalysis over BaMeO3 (Me=Mn, Co, Fe) Mixed Oxides at Low Temperature under Excess Oxygen
Authors: Xu Wentao , Cai Jinjun , Zhou Jicheng , Ou Yingpiao , Long Wei , You Zhimin , Luo Yushang
Published: November 2015

The direct catalytic decomposition of NO with high activity and N2 selectivity is a great challenge at low temperature under excess oxygen. Herein, we report the NO decomposition by microwave catalysis over BaMeO3 (Me=Mn, Co, Fe) mixed oxides for the first time at low temperature under excess oxygen, for which the BaCoO3 catalyst has an outstanding activity with a high NO conversion and N2 selectivity up to 99.8 % and 99.9 %, respectively, even at 250 °C. Comparatively, the best NO conversion is 93.7 % for BaMnO3 and only 64.1 % for BaFeO3 under microwave irradiation. H2 temperature‐programmed reduction, O2 temperature‐programmed desorption, and the microwave‐absorbing properties of the mixed oxides were characterized to illustrate possible reasons that cause such clear differences in the catalytic performance. Importantly, the apparent activation energies for BaMnO3, BaCoO3, and BaFeO3 are as low as 33.4, 13.7, and 46.7 kJ mol−1, respectively, which suggests a significant microwave catalytic effect.
Performance of a Metal Ion‐Doped Titania‐Coated Planar Photocatalytic Microreactor
Authors: Lin Cheng , Liu Mingyan , Yang Zhongguo
Published: November 2015

A novel planar photocatalytic microreactor coated with metal ion‐doped TiO2 was fabricated by chemical etching and sol‐gel techniques. The photocatalytic activity of the microreactor was evaluated by studying the degradation of methylene blue (MB) under ultraviolet light, visible light, and sunlight, and encouraging results were obtained. Analyses of the degradation products indicate that demethylation and ring‐opening reactions took place and that the mineralization of MB is a slow process. Kinetic studies of the MB degradation show that metal ion doping increases the reaction order. Comparing the applied microreactor with other conventional microchannel photocatalytic reactors, nearly the same degradation ratios and relatively higher degradation rates per unit reaction volume were obtained.
Laser Processing in the Manufacture of Dye‐Sensitized and Perovskite Solar Cell Technologies
Authors: Mincuzzi Girolamo , Palma Alessandro L. , Di Carlo Aldo , Brown Thomas M.
Published: November 2015

Dye‐sensitized and perovskite solar cells have seen tremendous efforts in their development in recent years. Amongst these developments are the design and implementation of fabrication techniques that can guarantee high performance as well as scalability over large areas. Laser processing has become a versatile and important tool in many industries and has also been applied successfully to both types of solar cell technologies, culminating in the demonstration of dye solar devices where all temperature treatments have been replaced with laser techniques, and of high‐performance solid‐state perovskite modules. Herein, we introduce concepts and review the available literature, pertaining to the effective utilization of laser beams for the development of both dye‐sensitized and perovskite photovoltaic technologies.