bluuebunny/crossref_metadata_2025 huggingface dataset:
Variations of the meteor echo heights at Beijing and Mohe, China
Authors: Liu Libo , Liu Huixin , Chen Yiding , Le Huijun , Sun Yang‐Yi , Ning Baiqi , Hu Lianhuan , Wan Weixing
Published: December 2016

Detecting the changing of the upper atmosphere is an important and challenging issue. The change in the meteor peak heights observed by a meteor radar should contain information of the neutral density in the meteoroid ablation region. In this work, observations from the VHF all‐sky meteor radars operated at Beijing (40.3°N, 116.2°E) and Mohe (53.5°N, 122.3°E), China, are collected to explore the temporal patterns of the meteor peak heights. The daily meteor peak height is determined through a least squares fitting of the height profile of meteor radar echoes under a normal distribution assumption. There are considerable seasonal variations in the meteor peak heights, being dominated by an annual component at Beijing and a semiannual one at Mohe. Moreover, the Ensemble Empirical Mode Decomposition (EEMD) is employed to determine the overall trends in the series of the meteor peak heights. The EEMD analysis reveals an overall decrease in the meteor peak heights at both stations, indicating the descending trend in neutral density near 90 km altitude at middle latitudes. The meteor peak heights show a rather weak solar activity effect at Beijing, which is different from the positive effects reported at some other sites.
Hot oxygen escape from Mars: Simple scaling with solar EUV irradiance
Authors: Cravens T. E. , Rahmati A. , Fox Jane L. , Lillis R. , Bougher S. , Luhmann J. , Sakai S. , Deighan J. , Lee Yuni , Combi M. , Jakosky B.
Published: December 2016

The evolution of the atmosphere of Mars and the loss of volatiles over the lifetime of the solar system is a key topic in planetary science. An important loss process for atomic species, such as oxygen, is ionospheric photochemical escape. Dissociative recombination of O2+ ions (the major ion species) produces fast oxygen atoms, some of which can escape from the planet. Many theoretical hot O models have been constructed over the years, although a number of uncertainties are present in these models, particularly concerning the elastic cross sections of O atoms with CO2. Recently, the Mars Atmosphere and Volatile Evolution mission has been rapidly improving our understanding of the upper atmosphere and ionosphere of Mars and its interaction with the external environment (e.g., solar wind), allowing a new assessment of this important loss process. The purpose of the current paper is to take a simple analytical approach to the oxygen escape problem in order to (1) study the role that variations in solar radiation or solar wind fluxes could have on escape in a transparent fashion and (2) isolate the effects of uncertainties in oxygen cross sections on the derived oxygen escape rates. In agreement with several more elaborate numerical models, we find that the escape flux is directly proportional to the incident solar extreme ultraviolet irradiance and is inversely proportional to the backscatter elastic cross section. The amount of O lost due to ion transport in the topside ionosphere is found to be about 5–10% of the total.
Development of intermediate‐scale structure at different altitudes within an equatorial plasma bubble: Implications for L‐band scintillations
Authors: Bhattacharyya A. , Kakad B. , Gurram P. , Sripathi S. , Sunda S.
Published: December 2016

An important aspect of the development of intermediate‐scale length (approximately hundred meters to few kilometers) irregularities in an equatorial plasma bubble (EPB) that has not been considered in the schemes to predict the occurrence pattern of L‐band scintillations in low‐latitude regions is how these structures develop at different heights within an EPB as it rises in the postsunset equatorial ionosphere due to the growth of the Rayleigh‐Taylor instability. Irregularities at different heights over the dip equator map to different latitudes, and their spectrum as well as the background electron density determine the strength of L‐band scintillations at different latitudes. In this paper, VHF and L‐band scintillations recorded at different latitudes together with theoretical modeling of the scintillations are used to study the implications of this structuring of EPBs on the occurrence and strength of L‐band scintillations at different latitudes. Theoretical modeling shows that while S4 index for scintillations on a VHF signal recorded at an equatorial station may be >1, S4 index for scintillations on a VHF signal recorded near the crest of the equatorial ionization anomaly (EIA) generally does not exceed the value of 1 because the intermediate‐scale irregularity spectrum at F layer peak near the EIA crest is shallower than that found in the equatorial F layer peak. This also explains the latitudinal distribution of L‐band scintillations. Thus, it is concluded that there is greater structuring of an EPB on the topside of the equatorial F region than near the equatorial F layer peak.
Three‐scale structure of diffusion region in the presence of cold ions
Authors: Divin A. , Khotyaintsev Yu. V. , Vaivads A. , André M. , Toledo‐Redondo S. , Markidis S. , Lapenta G.
Published: December 2016

Kinetic simulations and spacecraft observations typically display the two‐scale structure of collisionless diffusion region (DR), with electron and ion demagnetization scales governing the spatial extent of the DR. Recent in situ observations of the nightside magnetosphere, as well as investigation of magnetic reconnection events at the Earth's magnetopause, discovered the presence of a population of cold (tens of eV) ions of ionospheric origin. We present two‐dimensional particle‐in‐cell simulations of collisionless magnetic reconnection in multicomponent plasma with ions consisting of hot and cold populations. We show that a new cold ion diffusion region scale is introduced in between that of hot ions and electrons. Demagnetization scale of cold ion population is several times (∼4–8) larger than the initial cold ion gyroradius. Cold ions are accelerated and thermalized during magnetic reconnection and form ion beams moving with velocities close to the Alfvén velocity.
Spatiotemporal variations of characteristic repeating earthquake sequences along the Middle America Trench in Mexico
Authors: Dominguez Luis A. , Taira Taka'aki , Santoyo Miguel A.
Published: December 2016

Searching for repeating earthquakes allows the examination of spatiotemporal variation of slip budget in the subduction of the Cocos plate in the Guerrero‐Oaxaca region of Mexico. As different transient phenomena continuously load and unload stresses around asperities in an area where megathrust earthquakes nucleate, repeating earthquakes act as track markers for slip on the plate interface. We systematically examined 14 years of waveform records from 2001 through 2014 to identify repeating earthquakes along the subducting segment of the Cocos plate. An analysis of waveform similarity resulted in a significant number (224) of earthquake sequences with highly correlated waveforms (correlation coefficient cc ≥ 0.95 and spectral coherency coh ≥ 0.95). The reported set of correlated waveforms shows a well‐defined clustering in space and substantial temporal variability. We find a significant increase of repeating earthquake activity after the 20 March 2012 Ometepec (Mw7.4) and 18 April 2014 Tecpan (Mw7.2) earthquakes as a result of the postseismic relaxation. In contrast, the rupture zone of the 1985 (Mw8.1) Michoacán earthquake is completely devoid of repeating sequences, suggesting a strongly coupled segment. Examining the temporal behavior of repeating earthquake activity provides a new tool to better understand how creeping of the subduction thrust controls stress release and postseismic relaxation.
Uppermost mantle seismic velocity structure beneath USArray
Authors: Buehler J. S. , Shearer P. M.
Published: December 2016

We apply Pn tomography beneath the entire USArray footprint to image uppermost mantle velocity structure and anisotropy, as well as crustal thickness constraints, beneath the United States. The sparse source distribution in the eastern United States and the resulting longer raypaths provide new challenges and justify the inclusion of additional parameters that account for the velocity gradient in the mantle lid. At large scale, Pn velocities are higher in the eastern United States compared to the west, but we observe patches of lower velocities around the New Madrid seismic zone and below the eastern Appalachians. For much of the mantle lid below the central and eastern United States we find a moderate positive velocity gradient. In the western United States, we observe a moderate gradient in the region of the Juan de Fuca subduction zone, but no significant gradient to the south and east of this region. In terms of anisotropy, we find that the Pn fast axes generally do not agree with SKS splitting orientations, suggesting significant vertical changes in anisotropy in the upper mantle. In particular the circular pattern of the fast polarization direction of SKS in the western United States is much less pronounced in the Pn results, and in the eastern US the dominant Pn fast direction is approximately north‐south, whereas the SKS fast polarizations are oriented roughly parallel to the absolute plate motion direction.
Isoprene suppression of new particle formation: Potential mechanisms and implications
Authors: Lee Shan‐Hu , Uin Janek , Guenther Alex B. , de Gouw Joost A. , Yu Fangqun , Nadykto Alex B. , Herb Jason , Ng Nga L. , Koss Abigail , Brune William H. , Baumann Karsten , Kanawade Vijay P. , Keutsch Frank N. , Nenes Athanasios , Olsen Kevin , Goldstein Allen , Ouyang Qi
Published: December 2016

Secondary aerosols formed from anthropogenic pollutants and natural emissions have substantial impacts on human health, air quality, and the Earth's climate. New particle formation (NPF) contributes up to 70% of the global production of cloud condensation nuclei (CCN), but the effects of biogenic volatile organic compounds (BVOCs) and their oxidation products on NPF processes in forests are poorly understood. Observations show that isoprene, the most abundant BVOC, suppresses NPF in forests. But the previously proposed chemical mechanism underlying this suppression process contradicts atmospheric observations. By reviewing observations made in other forests, it is clear that NPF rarely takes place during the summer when emissions of isoprene are high, even though there are sufficient concentrations of monoterpenes. But at present it is not clear how isoprene and its oxidation products may change the oxidation chemistry of terpenes and how NOx and other atmospheric key species affect NPF in forest environments. Future laboratory experiments with chemical speciation of gas phase nucleation precursors and clusters and chemical composition of particles smaller than 10 nm are required to understand the role of isoprene in NPF. Our results show that climate models can overpredict aerosol's first indirect effect when not considering the absence of NPF in the southeastern U.S. forests during the summer using the current nucleation algorithm that includes only sulfuric acid and total concentrations of low‐volatility organic compounds. This highlights the importance of understanding NPF processes as function of temperature, relative humidity, and BVOC compositions to make valid predictions of NPF and CCN at a wide range of atmospheric conditions.
The influence of ozone forcing on blocking in the Southern Hemisphere
Authors: Dennison Fraser W. , McDonald Adrian , Morgenstern Olaf
Published: December 2016

We investigate the influence of ozone depletion and recovery on tropospheric blocking in the Southern Hemisphere. Blocking events are identified using a persistent positive anomaly method applied to 500 hPa geopotential height. Using the National Institute for Water and Atmospheric Research‐United Kingdom Chemistry and Aerosols chemistry‐climate model, we compare reference runs that include forcing due to greenhouse gases (GHGs) and ozone‐depleting substances to sensitivity simulations in which ozone‐depleting substances are fixed at their 1960 abundances and other sensitivity simulations with GHGs fixed at their 1960 abundances. Blocking events in the South Atlantic are shown to follow stratospheric positive anomalies in the Southern Annular Mode (SAM) index; this is not the case for South Pacific blocking events. This relationship means that summer ozone depletion, and corresponding positive SAM anomalies, leads to an increased frequency of blocking in the South Atlantic while having little effect in the South Pacific. Similarly, ozone recovery, having the opposite effect on the SAM, leads to a decline in blocking frequency in the South Atlantic, although this may be somewhat counteracted by the effect of increasing GHGs.
Development of an improved aerosol product over the Indian subcontinent: Blending model, satellite, and ground‐based estimates
Authors: Singh Randhir , Singh Charu , Ojha Satya P. , Kumar A. Senthil , Kumar A. S. Kiran
Published: December 2016

A comprehensive assessment of the aerosol optical depth (AOD) at 550 nm from European Centre for Medium‐Range Weather Forecasts (ECMWF), Moderate Resolution Imaging Spectroradiometer (MODIS), and Multiangle Imaging Spectroradiometer (MISR) has been performed with respect to the Aerosol Robotic Network (AERONET) measurements at 35 locations over the Indian subcontinent. For all of the stations, the mean relative errors for the collocated ECMWF, MODIS, and MISR AOD are 46.15%, 41.81%, and 39.98%, respectively. Compared with AERONET, ECMWF estimates suffer from a negative bias, whereas MODIS and MISR estimates suffer from a positive bias. The correlation of ECMWF, MODIS, and MISR AOD with AERONET observation is 0.73, 0.80, and 0.78, respectively. Analysis shows that approximately 52.12% of ECMWF, 60.51% of MODIS, and 62.63% of MISR AOD fall within the error envelopes (± 0.05 ± 0.15AODAERONET) of validation data from AERONET. This analysis indicates that both modeled and space‐based AOD measurements have large discrepancies over the Indian subcontinent. Due to the aerosol's significant role in altering the Earth radiation budget, there is an urgent need to develop an AOD product with reduced error. Therefore, a new AOD product at 550 nm has been developed using an optimum interpolation (OI) technique. For this purpose, a model‐derived AOD from ECMWF, remotely sensed AOD from MODIS, MISR, and in situ measured AOD from AERONET have been blended using the OI technique. A new product has been generated for 13 years (2003 to 2015) at 0.25° by 0.25° latitude/longitude and daily temporal resolution over the Indian subcontinent. When compared with AERONET observations, the new product has a negligible bias, with a mean relative error of 12.31% and a correlation of 0.99.
Sensitivity of midnineteenth century tropospheric ozone to atmospheric chemistry‐vegetation interactions
Authors: Hollaway M. J. , Arnold S. R. , Collins W. J. , Folberth G. , Rap A.
Published: December 2016

We use an Earth System model (HadGEM2‐ES) to investigate the sensitivity of midnineteenth century tropospheric ozone to vegetation distribution and atmospheric chemistry‐vegetation interaction processes. We conduct model experiments to isolate the response of midnineteenth century tropospheric ozone to vegetation cover changes between the 1860s and present day and to CO2‐induced changes in isoprene emissions and dry deposition over the same period. Changes in vegetation distribution and CO2 suppression of isoprene emissions between midnineteenth century and present day lead to decreases in global isoprene emissions of 19% and 21%, respectively. This results in increases in surface ozone over the continents of up to 2 ppbv and of 2–6 ppbv in the tropical upper troposphere. The effects of CO2 increases on suppression of isoprene emissions and suppression of dry deposition to vegetation are small compared with the effects of vegetation cover change. Accounting for present‐day climate in addition to present‐day vegetation cover and atmospheric CO2 concentrations leads to increases in surface ozone concentrations of up to 5 ppbv over the entire northern hemisphere (NH) and of up to 8 ppbv in the NH free troposphere, compared with a midnineteenth century control simulation. Ozone changes are dominated by the following: (1) the role of isoprene as an ozone sink in the low NOx midnineteenth century atmosphere and (2) the redistribution of NOx to remote regions and the free troposphere via PAN (peroxyacetyl nitrate) formed from isoprene oxidation. We estimate a tropospheric ozone radiative forcing of 0.264 W m−2 and a sensitivity in ozone radiative forcing to midnineteenth century to present‐day vegetation cover change of −0.012 W m−2.
Japanese space weather research activities
Authors: Ishii M.
Published: December 2016

In this paper, we present existing and planned Japanese space weather research activities. The program consists of several core elements, including a space weather prediction system using numerical forecasts, a large‐scale ground‐based observation network, and the cooperative framework “Project for Solar‐Terrestrial Environment Prediction (PSTEP)” based on a Grant‐in Aid for Scientific Research on Innovative Areas.
Nanoparticle Assisted Mechanical Delamination for Freestanding High Performance Organic Devices
Authors: Colodrero Silvia , Romero‐Gomez Pablo , Mantilla‐Perez Paola , Martorell Jordi
Published: December 2016

Organic electronics has the potential to be incorporated in any kind of surface morphology for wearable or fully portable applications. Unfortunately when organic devices, such as solar cells, are fabricated on flexible substrates, the device performance is severely limited unless the physical properties of such substrates are carefully chosen. Here, it is demonstrated that layers of nanoparticles with a size gradient distribution can be used to obtain high performance solar cell devices that can be effectively delaminated from an original flat and rigid glass substrate. Such sacrificial nanoparticles layers are incorporated in between the glass substrate and the semitransparent electrode of a polymer:fullerene (PTB7:PC71BM) cell. After the cell delamination, freestanding flexible devices with power conversion efficiencies as high as 7.12% are obtained, which corresponds to 90% of the performance of the same cell fabricated on a standard glass smooth surface.
Ethyl 2‐(tert‐Butoxycarbonyloxyimino)‐2‐cyanoacetate (Boc‐Oxyma): An Efficient Reagent for the Racemization Free Synthesis of Ureas, Carbamates and Thiocarbamates via Lossen Rearrangement
Authors: Manne Srinivasa Rao , Thalluri Kishore , Giri Rajat Subhra , Chandra Jyoti , Mandal Bhubaneswar
Published: December 2016

Boc‐Oxyma (Ethyl 2‐(tert‐butoxycarbonyloxyimino)‐2‐cyanoacetate) has been reported previously as an efficient coupling reagent for the synthesis of amides, peptides, esters, thioesters and hydroxamic acids. It is known for its excellent racemization suppression capability, and also as an environment friendly reagent as it generates only Oxyma as solid byproduct that can be recovered easily and recycled for the synthesis of the same reagent. In this update, we report a simple, efficient, environment friendly, chemoselective and racemization free method for the synthesis of ureas, carbamates and thiocarbamates from hydroxamic acids via Lossen rearrangement by using Boc‐Oxyma. We have achieved racemization free di‐ and tri‐peptidyl ureas with very good yield by using this protocol. A rigorous mechanistic investigation is also incorporated.

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Photo‐Electrical Characterization of Silicon Micropillar Arrays with Radial p/n Junctions Containing Passivation and Anti‐Reflection Coatings
Authors: Vijselaar Wouter , Elbersen Rick , Tiggelaar Roald M. , Gardeniers Han , Huskens Jurriaan
Published: December 2016

In order to assess the contributions of anti‐reflective and passivation effects in microstructured silicon‐based solar light harvesting devices, thin layers of aluminum oxide (Al2O3), silicon dioxide (SiO2), silicon‐rich silicon nitride (SiNx), and indium tin oxide (ITO), with a thickness ranging from 45 to 155 nm, are deposited onto regularly packed arrays of silicon micropillars with radial p/n junctions. Atomic layer deposition of Al2O3 yields the best conformal coating over the micropillars. The fact that layers made by low‐pressure chemical vapor deposition (SiO2 and SiNx) are not conformally deposited on the sidewalls of the Si micropillars do not influence the photoelectrical efficiency. For ITO, a change in composition along the micropillar height is measured, which leads to poor performance. For Al2O3, deconvolution of the contributions of passivation and anti‐reflection to the overall efficiency gain exhibits the importance of passivation in micro/nano‐structured Si devices. Al2O3‐coated samples perform the best, for both n/p and p/n configured pillars, yielding (relative) increases of 116% and 37% in efficiency of coated versus non‐coated samples for p‐type and n‐type base micropillar arrays, respectively.
Nature‐Inspired Electrochemical Energy‐Storage Materials and Devices
Authors: Wang Hua , Yang Yun , Guo Lin
Published: December 2016

Currently, tremendous efforts are being devoted to develop high‐performance electrochemical energy‐storage materials and devices. Conventional electrochemical energy‐storage systems are confronted with great challenges to achieve high energy density, long cycle‐life, excellent biocompatibility and environmental friendliness. The biological energy metabolism and storage systems have appealing merits of high efficiency, sophisticated regulation, clean and renewability, and the rational design and fabrication of advanced electrochemical energy‐storage materials and smart devices inspired by nature have made some breakthrough progresses, recently. In this review, we summarize the latest developments in the field of nature‐inspired electrochemical energy‐storage materials and devices. Specifically, the nature‐inspired exploration, preparation and modification of electrochemical energy‐storage related materials including the active materials, binders, and separators are introduced. Furthermore, nature‐inspired design and fabrication of smart energy‐storage devices such as self‐healing supercapacitors, supercapacitors with ultrahigh operating voltage, and self‐rechargeable batteries are also discussed. The review aims to provide insights and expanded research perspectives for further study in this exciting field based on our comprehensive discussions.
Monitoring Thermal Annealing of Perovskite Solar Cells with In Situ Photoluminescence
Authors: van Franeker Jacobus J. , Hendriks Koen H. , Bruijnaers Bardo J. , Verhoeven Martinus W. G. M. , Wienk Martijn M. , Janssen René A. J.
Published: December 2016

Layer deposition of organometal halide perovskites for solar cells usually involves tedious experimentation to establish the optimum processing conditions. Important parameters are the time and temperature of thermal annealing. Here, it is demonstrated that in situ photoluminescence allows to determine the optimal annealing procedure without fabricating complete solar cells. A deposition method is used in which dense layers of perovskite crystals are formed within seconds in ambient air by hot casting a mixture of lead acetate, lead chloride, and methylammonium iodide. The as‐cast perovskite layers are highly luminescent because charge carriers are unable to reach the charge extraction layers that quench the photoluminescence. Thermal annealing enhances charge transport and quenches the photoluminescence, but deteriorates the photovoltaic performance via decomposition of the perovskite if applied for a too long time. It is demonstrated that the optimal annealing time coincides with the time required for the in situ measured photoluminescence intensity to reach its baseline value for annealing temperatures in the range of 80–100 °C. This results in efficient (>14%) perovskite solar cells and shows that in situ photoluminescence is a simple but powerful tool for in‐line quality monitoring of perovskite films.
Au108S24(PPh3)16: Bestätigung des allgemeinen Konzeptes metalloider Cluster durch einen hochsymmetrischen nanoskaligen Goldcluster
Authors: Kenzler Sebastian , Schrenk Claudio , Schnepf Andreas
Published: December 2016

Die Reduktion von (Ph3P)AuCl mit NaBH4 in Gegenwart von HSC(SiMe3)3 führt zu einem der größten bisher beschriebenen metalloiden Goldcluster: Au108S24(PPh3)16 (1). In 1 sind die Goldatome im zentralen oktaedrischen Au44‐Kern wie in metallischem Gold angeordnet und von 48 oxidierten Goldatomen einer Au48S24‐Schale, einem neuartigen Baustein in der Goldchemie, umgeben. Die schützende Au48S24‐Schale wird durch 16 zusätzliche Au(PPh3)‐Einheiten abgeschlossen, was zu einer kompletten Abschirmung des Goldkerns führt. In 1 werden die Au‐Au‐Abstände von innen nach außen stärker molekular. 1 zeigt neue Strukturmotive im Bereich metalloider Goldcluster, die zum Teil jedoch typisch für Metallatome in metalloiden Clustern [MnRm (n>m)] sind.
AIEgen with Fluorescence–Phosphorescence Dual Mechanoluminescence at Room Temperature
Authors: Yang Jie , Ren Zichun , Xie Zongliang , Liu Yingjie , Wang Can , Xie Yujun , Peng Qian , Xu Bin , Tian Wenjing , Zhang Fan , Chi Zhenguo , Li Qianqian , Li Zhen
Published: December 2016

We report the first example of an AIEgen (DPP‐BO) with fluorescence–phosphorescence dual emission under mechanical stimulation. By carefully analyzing the crystal structure of DPP‐BO, the efficient intermolecular and intramolecular interactions should account for its unique mechanoluminescence (ML) properties, especially the abnormal phosphorescence, as further confirmed by controlled experiments and theoretical calculations for the presence of ISC transitions. These results provide important information for understanding the complex ML process, possibly opening up a new way to study the inherent mechanism of ML by broadening the application of AIEgens.
Pre‐contact fish choice and foraging efficiency at Tula, American Sāmoa
Authors: RIETH TIMOTHY M. , MORRISON ALEX E.
Published: December 2016

Marine foraging is an under‐studied aspect of Sāmoan archaeology, although it clearly played a primary role in subsistence, with implications for settlement and demography. A pair of previous ichthyoarchaeological studies identified general stability in fish exploitation during ∼1500–2000 year sequences. We present a foraging‐theory‐based analysis of fish remains from Tula Village, Tutuila Island. Our results identify a decrease in foraging efficiency, but there is no unequivocal evidence for resource depression. To frame this issue at a broader level, we re‐analyse published data for Fatu‐ma‐Futi, Tutuila Island, and To‘aga, Ofu Island. Our results are consistent with previous analyses in suggesting little change in the prevalence of particular fish families and the contribution of large‐bodied prey at these two sites. However, a degree of localised variability in dominant fish taxa is evident. Our analysis has implications for studies of resilience in nearshore marine environments, as well as methodological issues for data generated to examine foraging efficiency and resource depression.
Tandem Thorpe Reaction/Palladium Catalyzed Asymmetric Allylic Alkylation: Access to Chiral β‐enaminonitriles with Excellent Enantioselectivity
Authors: Bai Da‐Chang , Liu Xiu‐Yan , Li Hao , Ding Chang‐Hua , Hou Xue‐Long
Published: December 2016

A new type of nucleophile, a 3‐imino nitrile carbanion generated in situ by Thorpe reaction of acetonitrile with a base, was developed successfully and applied in a Pd‐catalyzed asymmetric allylic alkylation with mono‐substituted allyl reagents under Pd/SIOCPhox catalysis, affording β‐enaminonitrile products in high yields with excellent regio‐ and enantioselectivities.
Teaching young children to make accurate portion size estimations using a stimulus equivalence paradigm
Authors: Hausman Nicole L. , Borrero John C. , Fisher Alyssa , Kahng SungWoo
Published: December 2016

The prevalence of obesity among children and adolescents has increased over the past four decades. Obesity can be conceptualized as a problem related to energy balance, where more energy is consumed than is expended through physical activity. One way that children may have a positive energy balance is through the overconsumption of foods (i.e., eating large portion sizes). Therefore, interventions that teach children to make accurate portion size estimations may be important to maintain overall health. In the current study, seven children between the ages of 4 and 7 years were taught to make accurate portion size estimations using a stimulus equivalence paradigm. Results suggested that the stimulus equivalence paradigm was effective in teaching five of seven participants to make more accurate portion size estimations during posttraining. Furthermore, five of seven participants estimated the target portion size of a novel food during extension sessions. These findings extend the current literature related to teaching children to make accurate portion size estimations. Although this was a translational study, results might help to inform existing nutrition education programs aimed at teaching children healthier eating habits.
Cellular engineering for therapeutic protein production: product quality, host modification, and process improvement
Authors: Wells Evan , Robinson Anne Skaja
Published: December 2016

Recombinant proteins offer many therapeutic advantages unavailable in traditional small molecule drugs, but the need for cellular versus chemical synthesis complicates production. Avenues for producing therapeutic biologics are continuously expanding, and developments in biochemistry, cell biology, and bioengineering fuel new discoveries that promise safer, more efficient, and cheaper drugs for consumers. Numerous approaches to express recombinant proteins exist, but Escherichia coli, Saccharomyces cerevisiae, and mammalian systems (e.g. Chinese hamster ovary cells, CHO) are the most widely utilized. Improvements to production in these hosts have focused on novel expression cassettes, cell line modifications, engineering secretion pathways, and media design. Here, we describe recent developments for improving protein production in E. coli, S. cerevisiae, and CHO systems and compare recent advancements to previous knowledge in the field. With the expanding importance and prevalence of protein therapeutics, these improvements will serve as the framework for future discoveries.
Quantitative determination and evaluation of Paris polyphylla var. yunnanensis with different harvesting times using UPLC‐UV‐MS and FT‐IR spectroscopy in combination with partial least squares discriminant analysis
Authors: Yang Yuan‐Gui , Zhang Ji , Zhao Yan‐Li , Zhang Jin‐Yu , Wang Yuan‐Zhong
Published: December 2016

A rapid method was developed and validated by ultra‐performance liquid chromatography–triple quadrupole mass spectroscopy with ultraviolet detection (UPLC‐UV‐MS) for simultaneous determination of paris saponin I, paris saponin II, paris saponin VI and paris saponin VII. Partial least squares discriminant analysis (PLS‐DA) based on UPLC and Fourier transform infrared (FT‐IR) spectroscopy was employed to evaluate Paris polyphylla var. yunnanensis (PPY) at different harvesting times. Quantitative determination implied that the various contents of bioactive compounds with different harvesting times may lead to different pharmacological effects; the average content of total saponins for PPY harvested at 8 years was higher than that from other samples. The PLS‐DA of FT‐IR spectra had a better performance than that of UPLC for discrimination of PPY from different harvesting times.
Integrating Environmental, Social and Governance (ESG) Disclosure for a Sustainable Development: An Australian Study
Authors: Lokuwaduge Chitra Sriyani De Silva , Heenetigala Kumudini
Published: December 2016

Addressing environmental, social and governance (ESG) issues has become a critical part of business strategy. This article explores the extent of ESG reporting of metal and mining sector companies listed in the Australian Securities Exchange to determine the nature of ESG indicators in use in the sector. The current study argues that stakeholder engagement is the key to enhance company environmental policy and sustainable development. According to the results of this study, ESG reporting motives are highly influenced by reporting regulations. Given the diversity in reporting of ESG, comparability of ESG strategic performance is problematic. This study contributes towards developing an ESG disclosure index, which companies could use as a legitimacy tool that external stakeholders could use to reliably measure and compare the ESG performance of companies. It also reveals there is an increased demand for more empirical research on integration of sustainability into strategic planning process. Copyright © 2016 John Wiley & Sons, Ltd and ERP Environment
Gastropancreatic ligament: Description, incidence, and involvement during laparoscopic sleeve gastrectomy
Authors: Rebibo Lionel , Darmon Ilan , Peltier Johann , Dhahri Abdennaceur , Regimbeau Jean‐Marc
Published: December 2016

During laparoscopic sleeve gastrectomy (LSG), adhesions between the stomach and the pancreas are sometimes found, forming a “gastropancreatic ligament” (GPL). However, the GPL has only been described once in the literature, in 1985. The objective of this study was to determine the incidence of the GPL during LSG, describe this structure and assess its effect on the surgical technique. All patients undergoing primary LSG in our institution (n = 240) and patients referred for gastric fistula (GF) after primary LSG (n = 18) between January 2015 and December 2015 were included. The primary endpoint was the incidence of a GPL during primary LSG. The secondary endpoints were the postoperative complication rate, the postoperative GF rate, and the presence of this ligament during reoperation for GF. Among the 240 patients, a GPL was visible in 49 cases (20.4%) and was described as thin in 34 of these (69.4%). Twelve postoperative complications (5%) were observed, including seven major (2.9%). The GF rate was 2% (n = 5), not requiring reoperation. The gastric stenosis rate was 0.4% (n = 1). The GPL had been previously sectioned in one of the five patients (20%) with postoperative GF. During the study period, 18 patients were referred for GF and 14 were reoperated. A non‐sectioned GPL, not described in the operating report, was observed in four patients (28.5%). A GPL was identified in 20.4% of cases. Identification of a GPL could be important in the context of LSG, as section of the ligament allows tension‐free stapling to be performed and can therefore possibly reduce the risk of postoperative complications, particularly GF. Clin. Anat. 30:336–341, 2017. © 2017 Wiley Periodicals, Inc.
Fate of abstracts presented at the annual meetings of the American association of clinical anatomists
Authors: Furness Hugh , Miller George W. , Putt Oliver , Lewis Thomas L.
Published: December 2016

A recent study examined the rate of full‐length research paper publication following abstract presentation at the British association of clinical anatomists (BACA) annual meetings. The accepted standard for research dissemination is peer‐reviewed publication following presentation at a national or international meeting. The study objectives were quantitative assessment of the abstracts presented at the American Association of Clinical Anatomists' (AACA) annual meetings with regards to the rate of subsequent full‐length publication and comparison to BACA publication rates. All abstracts presented at the AACA annual meetings between 2003 and 2010 were analysed. MEDLINE was searched to identify peer‐reviewed publications arising from each presented abstract. In total, 1,120 abstracts were presented with 22.9% (n = 257) subsequently published as full‐length research papers. The mean number of abstracts presented each year was 140.0 ± 35.9. The median time to publication was 16 months. Chi‐squared analysis showed the publication rate of abstracts presented at AACA (22.9%) was not statistically significantly different to BACA (20.4%) (P = 0.09). A total of 11.3% (n = 29) of the articles were published as full‐length research articles before presentation as an abstract at an AACA meeting compared to 5.4% of abstracts presented at a BACA meeting. These rates are lower but comparable to those of surgical specialty meetings. Further work should try to identify any concerning reasons for the reduced rate of abstract publication in anatomical research. Clin. Anat. 30:140–144, 2017. © 2017 Wiley Periodicals, Inc.
Exploring the Least Studied Australian Eucalypt Genera: Corymbia and Angophora for Phytochemicals with Anticancer Activity against Pancreatic Malignancies
Authors: Bhuyan Deep Jyoti , Vuong Quan V. , Bond Danielle R. , Chalmers Anita C. , van Altena Ian A. , Bowyer Michael C. , Scarlett Christopher J.
Published: December 2016

While the pharmacological and toxicological properties of eucalypts are well known in indigenous Australian medicinal practice, investigations of the bioactivity of eucalypt extracts against high mortality diseases such as pancreatic cancer in Western medicine have to date been limited, particularly amongst the genera Corymbia and Angophora. Four Angophora and Corymbia species were evaluated for their phytochemical profile and efficacy against both primary and secondary pancreatic cancer cell lines. The aqueous leaf extract of Angophora hispida exhibited statistically higher total phenolic content (107.85 ± 1.46 mg of gallic acid equiv. per g) and total flavonoid content (57.96 ± 1.93 mg rutin equiv. per g) and antioxidant capacity compared to the other tested eucalypts (P < 0.05). Both A. hispida and A. floribunda aqueous extracts showed statistically similar saponin contents. Angophora floribunda extract exerted significantly greater cell growth inhibition of 77.91 ± 4.93% followed by A. hispida with 62.04 ± 7.47% (P < 0.05) at 100 μg/ml in MIA PaCa‐2 cells with IC50 values of 75.58 and 87.28 μg/ml, respectively. More studies are required to isolate and identify the bioactive compounds from these two Angophora species and to determine their mode of action against pancreatic malignancies.
From Active‐Site Models to Real Catalysts: Importance of the Material Gap in the Design of Pd Catalysts for Methane Oxidation
Authors: Doan Hieu A. , Sharma Munish K. , Epling William S. , Grabow Lars C.
Published: December 2016

Rapid computational screening to aid novel catalyst design has evolved into an important and ubiquitous tool in modern heterogeneous catalysis. A possible shortcoming of this approach, however, is the material gap, that is, simplified computational models used for catalyst screening do not always capture the complexity of real catalytic systems. Here we investigate the importance of the material gap for complete methane oxidation over supported Pd/γ‐Al2O3 catalysts using a combination of DFT simulations and temperature‐programmed oxidation experiments. The Pd/γ‐Al2O3 active site was approximated by four models of increasing complexity, namely Pd(1 0 0), Pd(2 1 1), PdO(1 0 1), and Pd10/γ‐Al2O3(1 1 0), and each was also modified with metal promoters to discover reactivity trends. Although the unpromoted Pd model surfaces exhibit different methane activation activities, our DFT results indicate that an experimentally verified performance trend can be predicted for their promoted counterparts irrespective of the active‐site representation. We attribute the robustness of the trend predictions in this particular system to localized changes in the electron density during methane activation. Overall, our work supports the commonly practiced active‐site model simplifications during computational catalyst screening and provides fundamental insight into the qualitative agreement between theory and experiment for methane oxidation over promoted Pd catalysts.
Gas‐Solid Flow in an Airlift Loop Reactor: A Cluster Structure‐Dependent Drag Model
Authors: Chen Juhui , Meng Cheng , Wang Shuai , Song Xiaojiao
Published: December 2016

The hydrodynamic characteristics and heterogeneous structures in an airlift loop reactor (ALR) are analyzed by a computational fluid dynamics (CFD) approach. Based on the two‐fluid model, a modified cluster structure‐dependent (CSD) drag model under consideration of the cluster effects is applied to the prediction of the non‐uniform flow structure in the ALR. In comparison with experimental data and the traditional drag model, the present model enables a better prediction. The distributions of the local granular temperature in different regions of the ALR are indicated. The granular temperature in the particle diffluence region was found to be higher than that in the draft tube and annular zones.
Mesoporous NiCo2O4 Micro/nanospheres with Hierarchical Structures for Supercapacitors and Methanol Electro–oxidation
Authors: Zhang Liheng , Zhang Daoming , Ren Zhen , Huo Mengfei , Dang Guoju , Min Fanqi , Zhang Quansheng , Xie Jingying
Published: December 2016

Mesoporous NiCo2O4 materials with different 3D structures, including flower‐like hierarchical structures (NCO‐flower‐like HSs), nanoflake@nanoneedle‐like multiple hierarchical structures (NCO‐MHS) and urchin‐like hierarchical structures (NCO‐urchin‐like HSs), were prepared by using a facile, one‐step, NH4F‐induced hydrothermal method followed by thermal annealing. The physicochemical characterization of the as‐prepared materials was investigated by means of X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectroscopy. The performance of the synthesized NiCo2O4 material as supercapacitor electrode materials was measured and the results demonstrate that the NCO‐MHSs and NCO‐urchin‐like HSs exhibit high specific capacitance values of 640 and 655 F ⋅ g−1 at a current density of 1 A ⋅ g−1, whereas the capacitance retention is 99.6 and 95 %, respectively, after 1000 cycles at a current density of 5 A ⋅ g−1. The electrocatalytic performance of synthetized NiCo2O4 for methanol electro‐oxidation was evaluated in 1 M KOH electrolyte. The NCO‐MHSs and NCO‐urchin‐like HSs deliver an electro‐oxidation current density of 51 and 48.5 A ⋅ g−1, respectively, at 0.65 V with excellent stability. The results indicate that the hierarchical structure of NiCo2O4 offers a promising electrode material for supercapacitors and methanol electro‐oxidation.
Mechanistic Insight into the Oxidation of Organic Phenylselenides by H2O2
Authors: Ribaudo Giovanni , Bellanda Massimo , Menegazzo Ileana , Wolters Lando P. , Bortoli Marco , Ferrer‐Sueta Gerardo , Zagotto Giuseppe , Orian Laura
Published: December 2016

The oxidation of organic phenylselenides by H2O2 is investigated in model compounds, namely, n‐butyl phenyl selenide (PhSe(nBu)), bis(phenylselanyl)methane (PhSeMeSePh), diphenyl diselenide (PhSeSePh), and 1,2‐bis(phenylselanyl)ethane (PhSeEtSePh). Through a combined experimental (1H and 77Se NMR) and computational approach, we characterize the direct oxidation of monoselenide to selenoxide, the stepwise double oxidation of PhSeMeSePh that leads to different diastereomeric diselenoxides, the complete oxidation of the diphenyldiselenide that leads to selenium–selenium bond cleavage, and the subsequent formation of the phenylseleninic product. The oxidation of PhSeEtSePh also results in the formation of phenylseleninic acid along with 1‐(vinylseleninyl)benzene, which is derived from a side elimination reaction. The evidence of a direct mechanism, in addition to an autocatalytic mechanism that emerges from kinetic studies, is discussed. By considering our observations of diselenides with chalcogen atoms that are separated by alkyl spacers of different length, a rationale for the advantage of diselenide versus monoselenide catalysts is presented.
Highly Flexible Multifunctional Biopaper Comprising Chitosan Reinforced by Ultralong Hydroxyapatite Nanowires
Authors: Sun Tuan‐Wei , Zhu Ying‐Jie , Chen Feng
Published: December 2016

Highly flexible multifunctional biopaper comprising ultralong hydroxyapatite nanowires and chitosan (UHANWs/CS), with high weight fractions of ultralong hydroxyapatite nanowires (UHANWs) up to 100 wt. %, is reported. The as‐prepared UHANWs/CS composite biopaper has high flexibility and superior mechanical properties even when the weight fraction of UHANWs is as high as 90 wt. %. In contrast, the control samples consisting of hydroxyapatite nanorods and chitosan (HANRs/CS) with weight fractions of HANRs higher than 66.7 wt.% cannot be obtained in the form of the flexible membrane. The ultimate tensile strength and Young's modulus of the UHANWs/CS composite biopaper are about 3.2 times and 4.3 times those of the HANRs/CS membrane with the same weight fraction of HAP, respectively. In addition, the UHANWs/CS composite biopaper (90 wt. % UHANWs) can be used for color printing using a commercial ink‐jet printer. The surface wettability, swelling ratio, and water vapor transmission rate of the UHANWs/CS composite biopaper are adjustable by changing the addition amount of UHANWs. In vitro experiments indicate that the UHANWs/CS composite biopaper has good degradability, high acellular bioactivity and high biocompatibility. The as‐prepared UHANWs/CS composite biopaper is therefore promising for various biomedical applications such as wound dressing, bone‐fracture fixation, and bone‐defect repair.
Facile Access to Unprecedented Electron‐Precise Monohydrodiboranes(4), cis‐1,2‐Dihydrodiboranes(4), and a 1,1‐Dihydrodiborane(5)
Authors: Arrowsmith Merle , Braunschweig Holger , Radacki Krzysztof , Thiess Torsten , Turkin Arthur
Published: December 2016

2,3‐Bis(dimethylamino)‐substituted B2N2C2 heterocycles underwent selective dimethylamino/hydride exchange with either one or two equivalents of BH3⋅SMe2 to give the corresponding cyclic monohydrido‐ or (cis)1,2‐dihydridodiboranes(4), respectively. Upon either heating or irradiation in solution, the latter underwent ring contraction to the corresponding five‐membered BN2C2 heterocycles, whereas irradiation of the 1,2‐dimethylaminoethene‐supported 1,2‐dihydridodiborane(4) in the presence of PEt3 gave an unprecedented unsymmetrical 1,1‐dihydrodiborane(5) phosphine adduct.
Ring‐Expansion Approach to Medium‐Sized Lactams and Analysis of Their Medicinal Lead‐Like Properties
Authors: Baud Laetitia G. , Manning Morgan A. , Arkless Helen L. , Stephens Thomas C. , Unsworth William P.
Published: December 2016

Medium‐sized rings are widely considered to be under‐represented in biological screening libraries for lead identification in medicinal chemistry. To help address this, a library of medium‐sized lactams has been generated by using a simple, scalable and versatile ring‐expansion protocol. Analysis of the library by using open‐access computational tool LLAMA suggested that these lactams and their derivatives have highly promising physicochemical and 3D spatial properties and thus have much potential in drug discovery.