bluuebunny/crossref_metadata_2025 huggingface dataset:
A new process approach for slant field plates in GaN-based high-electron-mobility transistors
Authors: Suemitsu Tetsuya , Kobayashi Kengo , Hatakeyama Shinya , Yasukawa Nana , Yoshida Tomohiro , Otsuji Taiichi , Piedra Daniel , Palacios Tomás
Published: November 2015

A new process approach to realize a slant field plate — a field plate (FP) gradually separated from the semiconductor surface from the gate edge toward the drain — is reported. A multistep SiCN dielectric film is used to make a sloped sidewall in the dielectric film consisting of a slant FP. The sidewall shape is controlled by the number of steps in SiCN. AlGaN/GaN high-electron-mobility transistors (HEMTs) with slant and conventional FPs are prepared using this technique. The advantage of slant FPs over conventional FPs is experimentally confirmed as a result of reduced current collapse, higher current gain cutoff frequency, and higher off-state breakdown voltage.
Effect of gelatin on the water dispersion and centrifugal purification of single-walled carbon nanotubes
Authors: Maria Kazi Hanium , Mieno Tetsu
Published: November 2015

We report a convenient and effective procedure for the water dispersion and purification of single-walled carbon nanotubes (SWNTs). The purification procedure involves a combination of dispersion and centrifugation, in which gelatin; an environmentally friendly material is used as a dispersing agent. It has been found that an aqueous solution of gelatin effectively disperses SWNTs for more than a month. Another advantage of using gelatin as a dispersing agent is that it can be easily removed by washing with water and filtration. The centrifugation procedure employs a centrifugal force of about 2500 times the gravitational force to separate the particles. Although carbonaceous and metallic impurities usually have higher density than SWNTs in arc-produced carbon soot, the centrifugation can easily remove impurities leaving undamaged SWNTs in solution when appropriate centrifugal force and a centrifugation time are used. Centrifugation is carried out for three times to sufficiently remove impurities. Finally, the SWNTs are separated from the gelatin by heating in water and filtering.
Magnetic reconnection in the near‐Mars magnetotail: MAVEN observations
Authors: Harada Y. , Halekas J. S. , McFadden J. P. , Mitchell D. L. , Mazelle C. , Connerney J. E. P. , Espley J. , Larson D. E. , Brain D. A. , Andersson L. , DiBraccio G. A. , Collinson G. A. , Livi R. , Hara T. , Ruhunusiri S. , Jakosky B. M.
Published: November 2015

We report Mars Atmosphere and Volatile EvolutioN (MAVEN) observations of electrons, ions, and magnetic fields which provide comprehensive demonstration of magnetic reconnection signatures in the Martian magnetotail. In the near‐Mars tail current sheet at XMSO∼−1.3RM, trapped electrons with two‐sided loss cones were observed, indicating the closed magnetic field topology. In the closed field region, MAVEN observed Hall magnetic field signatures and Marsward bulk flows of H+, O+, and
ions, which suggest the presence of X lines tailward from the spacecraft. Velocity distribution functions of the reconnection outflow ions exhibit counterstreaming beams separated along the current sheet normal, and their bulk velocities in the outflow direction inversely depend on ion mass. These characteristics are in qualitative agreement with previous multispecies kinetic simulations. The near‐Mars magnetotail provides a unique environment for studying multi‐ion reconnection.
Marsward and tailward ions in the near‐Mars magnetotail: MAVEN observations
Authors: Harada Y. , Halekas J. S. , McFadden J. P. , Mitchell D. L. , Mazelle C. , Connerney J. E. P. , Espley J. , Larson D. E. , Brain D. A. , DiBraccio G. A. , Curry S. M. , Hara T. , Livi R. , Ruhunusiri S. , Jakosky B. M.
Published: November 2015

We present Mars Atmosphere and Volatile EvolutioN (MAVEN) observations of Marsward and tailward fluxes of suprathermal (>25 eV) ions in the near‐Mars (∼1–1.5 Mars radii downstream) magnetotail. Statistical results show that the Marsward proton flux and magnetic field draping pattern are well organized by the upstream motional electric field direction. We observe both significant Marsward proton fluxes and tightly wrapped magnetic field lines in the hemisphere pointed in the opposite direction to the upstream electric field. These characteristics are very similar to those observed at Venus. On the other hand, the net flux of oxygen ions points tailward on average in the Martian tail, while net Venusward flows of oxygen ions were observed frequently in the same hemisphere at Venus. The mechanism by which the Marsward proton flux is produced in the presence of tailward oxygen ion flux remains unclear.
Model insights into energetic photoelectrons measured at Mars by MAVEN
Authors: Sakai Shotaro , Rahmati Ali , Mitchell David L. , Cravens Thomas E. , Bougher Stephen W. , Mazelle Christian , Peterson W. K. , Eparvier Francis G. , Fontenla Juan M. , Jakosky Bruce M.
Published: November 2015

Photoelectrons are important for heating, ionization, and airglow production in planetary atmospheres. Measured electron fluxes provide insight into the sources and sinks of energy in the Martian upper atmosphere. The Solar Wind Electron Analyzer instrument on board the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft measured photoelectrons including Auger electrons with 500 eV energies. A two‐stream electron transport code was used to interpret the observations, including Auger electrons associated with K shell ionization of carbon, oxygen, and nitrogen. It explains the processes that control the photoelectron spectrum, such as the solar irradiance at different wavelengths, external electron fluxes from the Martian magnetosheath or tail, and the structure of the upper atmosphere (e.g., the thermal electron density). Our understanding of the complex processes related to the conversion of solar irradiances to thermal energy in the Martian ionosphere will be advanced by model comparisons with measurements of suprathermal electrons by MAVEN.
Altitude dependence of nightside Martian suprathermal electron depletions as revealed by MAVEN observations
Authors: Steckiewicz M. , Mazelle C. , Garnier P. , André N. , Penou E. , Beth A. , Sauvaud J.‐A. , Toublanc D. , Mitchell D. L. , McFadden J. P. , Luhmann J. G. , Lillis R. J. , Connerney J. E. P. , Espley J. R. , Andersson L. , Halekas J. S. , Larson D. E. , Jakosky B. M.
Published: November 2015

The MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft is providing new detailed observations of the Martian ionosphere thanks to its unique orbital coverage and instrument suite. During most periapsis passages on the nightside ionosphere suprathermal electron depletions were detected. A simple criterion was implemented to identify the 1742 depletions observed from 16 November 2014 to 28 February 2015. A statistical analysis reveals that the main ion and electron populations within the depletions are surprisingly constant in time and altitude. Absorption by CO2 is the main loss process for suprathermal electrons, and electrons that strongly peaked around 6 eV are resulting from this interaction. The observation of depletions appears however highly dependent on altitude. Depletions are mainly located above strong crustal magnetic sources above 170 km, whereas the depletions observed for the first time below 170 km are globally scattered onto the Martian surface with no particular dependence on crustal fields.
The structure and variability of Mars upper atmosphere as seen in MAVEN/IUVS dayglow observations
Authors: Jain S. K. , Stewart A. I. F. , Schneider N. M. , Deighan J. , Stiepen A. , Evans J. S. , Stevens M. H. , Chaffin M. S. , Crismani M. , McClintock W. E. , Clarke J. T. , Holsclaw G. M. , Lo D. Y. , Lefèvre F. , Montmessin F. , Thiemann E. M. B. , Eparvier F. , Jakosky B. M.
Published: November 2015

We report a comprehensive study of Mars dayglow observations focusing on upper atmospheric structure and seasonal variability. We analyzed 744 vertical brightness profiles comprised of ∼109,300 spectra obtained with the Imaging Ultraviolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) satellite. The dayglow emission spectra show features similar to previous UV measurements at Mars. We find a significant drop in thermospheric scale height and temperature between LS = 218° and LS = 337–352°, attributed primarily to the decrease in solar activity and increase in heliocentric distance. We report the detection of a second, low‐altitude peak in the emission profile of OI 297.2 nm, confirmation of the prediction that the absorption of solar Lyman alpha emission is an important energy source there. The
UV doublet peak intensity is well correlated with simultaneous observations of solar 17–22 nm irradiance at Mars.
Retrieval of CO2 and N2 in the Martian thermosphere using dayglow observations by IUVS on MAVEN
Authors: Evans J. S. , Stevens M. H. , Lumpe J. D. , Schneider N. M. , Stewart A. I. F. , Deighan J. , Jain S. K. , Chaffin M. S. , Crismani M. , Stiepen A. , McClintock W. E. , Holsclaw G. M. , Lefèvre F. , Lo D. Y. , Clarke J. T. , Eparvier F. G. , Thiemann E. M. B. , Chamberlin P. C. , Bougher S. W. , Bell J. M. , Jakosky B. M.
Published: November 2015

We present direct number density retrievals of carbon dioxide (CO2) and molecular nitrogen (N2) for the upper atmosphere of Mars using limb scan observations during October and November 2014 by the Imaging Ultraviolet Spectrograph on board NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. We use retrieved CO2 densities to derive temperature variability between 170 and 220 km. Analysis of the data shows (1) low‐mid latitude northern hemisphere CO2 densities at 170 km vary by a factor of about 2.5, (2) on average, the N2/CO2 increases from 0.042 ± 0.017 at 130 km to 0.12 ± 0.06 at 200 km, and (3) the mean upper atmospheric temperature is 324 ± 22 K for local times near 14:00.
Enhanced subarctic Pacific stratification and nutrient utilization during glacials over the last 1.2 Myr
Authors: Knudson Karla P. , Ravelo Ana Christina
Published: November 2015

The relationship between climate, biological productivity, and nutrient flux is of considerable interest in the subarctic Pacific, which represents an important high‐nitrate, low‐chlorophyll region. While previous studies suggest that changes in iron supply and/or physical ocean stratification could hypothetically explain orbital‐scale fluctuations in subarctic Pacific nutrient utilization and productivity, previous records of nutrient utilization are too short to evaluate these relationships over many glacial‐interglacial cycles. We present new, high‐resolution records of sedimentary δ15N, which offer the first opportunity to evaluate systematic, orbital‐scale variations in subarctic Pacific nitrate utilization from 1.2 Ma. Nitrate utilization was enhanced during all glacials, varied with orbital‐scale periodicity since the mid‐Pleistocene transition, was strongly correlated with enhanced aeolian dust and low atmospheric CO2, but was not correlated with productivity. These results suggest that glacial stratification, rather than iron fertilization, systematically exerted an important regional control on nutrient utilization and air‐sea carbon flux.
On the dependence of storm time ULF wave power on magnetopause location: Impacts for ULF wave radial diffusion
Authors: Murphy Kyle R. , Mann Ian R. , Sibeck David G.
Published: November 2015

Ultralow frequency (ULF) waves play a crucial role in energetic particle dynamics in the inner magnetosphere. We examine the role of the magnetopause location in controlling the amplitude and penetration of ULF waves within the inner magnetosphere during 63 coronal mass ejection (CME)‐driven and corotating interaction region (CIR)‐driven geomagnetic storms. Significantly, at the time when the magnetopause is most compressed, ULF wave power increases and penetrates to the deepest L shells. Most likely this is explained by proximity to the energy source and accumulation of energy within a smaller volume through solar wind‐magnetopause‐magnetosphere coupling, and changes in the storm time Alfvén continuum resulting from variations in the cold plasma density. The observed ULF wave power is consistently larger than Kp‐dependent statistical estimates—especially in the heart of the outer radiation belt. This has important implications for radiation belt dynamics, including main phase loss and storm time ULF wave radial diffusion.
Lightning as a space‐weather hazard: UK thunderstorm activity modulated by the passage of the heliospheric current sheet
Authors: Owens M. J. , Scott C. J. , Bennett A. J. , Thomas S. R. , Lockwood M. , Harrison R. G. , Lam M. M.
Published: November 2015

Lightning flash rates, RL, are modulated by corotating interaction regions (CIRs) and the polarity of the heliospheric magnetic field (HMF) in near‐Earth space. As the HMF polarity reverses at the heliospheric current sheet (HCS), typically within a CIR, these phenomena are likely related. In this study, RL is found to be significantly enhanced at the HCS and at 27 days prior/after. The strength of the enhancement depends on the polarity of the HMF reversal at the HCS. Near‐Earth solar and galactic energetic particle fluxes are also ordered by HMF polarity, though the variations qualitatively differ from RL, with the main increase occurring prior to the HCS crossing. Thus, the CIR effect on lightning is either the result of compression/amplification of the HMF (and its subsequent interaction with the terrestrial system) or that energetic particle preconditioning of the Earth system prior to the HMF polarity change is central to solar wind lightning coupling mechanism.
Accuracy of short‐term sea ice drift forecasts using a coupled ice‐ocean model
Authors: Schweiger Axel J. , Zhang Jinlun
Published: November 2015

Arctic sea ice drift forecasts of 6 h–9 days for the summer of 2014 are generated using the Marginal Ice Zone Modeling and Assimilation System (MIZMAS); the model is driven by 6 h atmospheric forecasts from the Climate Forecast System (CFSv2). Forecast ice drift speed is compared to drifting buoys and other observational platforms. Forecast positions are compared with actual positions 24 h–8 days since forecast. Forecast results are further compared to those from the forecasts generated using an ice velocity climatology driven by multiyear integrations of the same model. The results are presented in the context of scheduling the acquisition of high‐resolution images that need to follow buoys or scientific research platforms. RMS errors for ice speed are on the order of 5 km/d for 24–48 h since forecast using the sea ice model compared with 9 km/d using climatology. Predicted buoy position RMS errors are 6.3 km for 24 h and 14 km for 72 h since forecast. Model biases in ice speed and direction can be reduced by adjusting the air drag coefficient and water turning angle, but the adjustments do not affect verification statistics. This suggests that improved atmospheric forecast forcing may further reduce the forecast errors. The model remains skillful for 8 days. Using the forecast model increases the probability of tracking a target drifting in sea ice with a 10 km × 10 km image from 60 to 95% for a 24 h forecast and from 27 to 73% for a 48 h forecast.
Robust optimization of well location to enhance hysteretical trapping of CO2: Assessment of various uncertainty quantification methods and utilization of mixed response surface surrogates
Authors: Babaei Masoud , Pan Indranil , Alkhatib Ali
Published: November 2015

The paper aims to solve a robust optimization problem (optimization in presence of uncertainty) for finding the optimal locations of a number of CO2injection wells for geological sequestration of carbon dioxide in a saline aquifer. The parametric uncertainties are the interfacial tension between CO2and aquifer brine, the Land's trapping coefficient and the boundary aquifer's absolute permeability. The spatial uncertainties are due to the channelized permeability field which exhibits a binary channel‐non‐channel system. The objective function of the optimization is the amount of residually trapped CO2due to the hysteresis of the relative permeability curves. A risk‐averse value derived from the cumulative density function of the distribution of the amount of trapped gas is chosen as the objective function value. In order to ensure that the uncertainties are effectively taken into account, Monte Carlo simulation and Polynomial Chaos Expansion (PCE)‐based methods are used and compared with each other. For different cases of parametric and spatial uncertainties, the most accurate uncertainty quantification (UQ) method is chosen to be integrated within the optimization algorithm. While for parametric uncertainty cases of up to two uncertain variables, PCE‐based methods computationally outperform Monte Carlo simulations, it is shown that for the multimodal distributions of the function of trapped gas occurring for the spatial uncertainty case, Monte Carlo simulations are more reliable than PCE‐based UQ methods. For the discrete (integer) optimization problem, various mixed response surface surrogate models are tested and the robust optimization resulted in optimal CO2injection well locations.
Characteristics of a rapid, point‐of‐care lateral flow immunoassay for the diagnosis of sickle cell disease
Authors: McGann Patrick T. , Schaefer Beverly A. , Paniagua Mary , Howard Thad A. , Ware Russell E.
Published: November 2015

Sickle cell disease (SCD) is a common and life‐threatening hematological disorder, affecting approximately 400,000 newborns annually worldwide. Most SCD births occur in low‐resource countries, particularly in sub‐Saharan Africa, where limited access to accurate diagnostics results in early mortality. We evaluated a prototype immunoassay as a novel, rapid, and low‐cost point‐of‐care (POC) diagnostic device (Sickle SCAN™) designed to identify HbA, HbS, and HbC. A total of 139 blood samples were scored by three masked observers and compared to results using capillary zone electrophoresis. The sensitivity (98.3–100%) and specificity (92.5–100%) to detect the presence of HbA, HbS, and HbS were excellent. The test demonstrated 98.4% sensitivity and 98.6% specificity for the diagnosis of HbSS disease and 100% sensitivity and specificity for the diagnosis of HbSC disease. Most variant hemoglobins, including samples with high concentrations of HbF, did not interfere with the ability to detect HbS or HbC. Additionally, HbS and HbC were accurately detected at concentrations as low as 1–2%. Dried blood spot samples yielded clear positive bands, without loss of sensitivity or specificity, and devices stored at 37°C gave reliable results. These analyses indicate that the Sickle SCAN POC device is simple, rapid, and robust with high sensitivity and specificity for the detection of HbA, HbS, and HbC. The ability to obtain rapid and accurate results with both liquid blood and dried blood spots, including those with newborn high‐HbF phenotypes, suggests that this POC device is suitable for large‐scale screening and potentially for accurate diagnosis of SCD in limited resource settings. Am. J. Hematol. 91:205–210, 2016. © 2015 Wiley Periodicals, Inc.
Pair housing of Vervets/African Green Monkeys for biomedical research
Authors: Jorgensen Matthew J. , Lambert Kelsey R. , Breaux Sarah D. , Baker Kate C. , Snively Beverly M. , Weed James L.
Published: November 2015

Vervets, also known as African green monkeys, are a nonhuman primate species widely used in biomedical research. However, there are currently few references available describing techniques and rates of success for pair‐housing this species. We present data from four cohorts of vervets from three different facilities: (i) the Wake Forest Vervet Research Colony (VRC; n = 72 female pairs, n= 52 male pairs), (ii) the University of Louisiana at Lafayette—New Iberia Research Center (UL‐NIRC; n = 57 female pairs, n = 54 male pairs), (iii) the Tulane National Primate Research Center (TNRPC; n = 18 male pairs), and (iv) a cohort of imported males (n = 18 pairs) at Wake Forest. Compatibility was measured at 14, 30, and 60 days following introduction. Success rates for pair‐housing at 14 days ranged from 96% to 98% for females and 96% to 100% for males at the VRC and UL‐NIRC but were lower in the smaller imported male cohorts (TNPRC: 50%; WF: 28%). Among the UL‐NIRC cohort and VRC male cohort, most of the pair separations after 14 days were due to reasons unrelated to social incompatibility. In contrast, a large proportion of TNPRC and imported male pairs successful at 14 days required separation within 60 days due to incompatibility. Multiple logistic regressions were performed using cohort, mean age of pair and weight difference between pair‐mates as potential predictors of compatibility at 14 days. All three predicted the 14‐day outcome in males but not females. A separate analysis in the VRC cohort found no evidence that prior familiarity in a group setting influenced outcomes. Variations in success rates across cohorts may have been influenced by introduction methodology. Behavioral differences between vervets and macaques, coupled with our findings, lead us to theorize that the gradual introduction techniques commonly implemented to pair house macaques may not be beneficial or suitable for this species. Am. J. Primatol. 79:e22501, 2017. © 2015 Wiley Periodicals, Inc.
Theory and Practice and the Neutral's Persona
Authors: Creo Robert A.
Published: November 2015

Editor's note: Longtime Alternatives columnist Bob Creo, a veteran Pittsburgh neutral, is revisiting his classic CPR Institute website columns of a decade ago in a Back to Basics Series that he has subtitled “Human Problems, Human Solutions.” These updated and expanded columns, in print for the first time, began late last year. He has revisited and re‐examined mediation‐room techniques and practice issues. This month, he returns to the second column he wrote at www.cpradr.org a decade ago, and brings it forward.
Morphology and toughness enhancements in recycled high‐density polyethylene (rHDPE) via solid‐state shear pulverization (SSSP) and solid‐state/melt extrusion (SSME)
Authors: Miu Evan V. , Fox Andrew J. , Jubb Samuel H. , Wakabayashi Katsuyuki
Published: November 2015

Solid‐state, mechanochemical polymer processing techniques are explored as an effective and sustainable solution to appearance and performance issues commonly associated with recycled plastic products. Post‐consumer high‐density polyethylene (HDPE) from milk jugs is processed via conventional twin screw extrusion (TSE), solid‐state shear pulverization (SSSP), and solid‐state/melt extrusion (SSME), and compared to the as‐received and virgin forms regarding output attributes and mechanical properties, as well as morphology. Solid‐state processing methods, particularly SSME with a harsh screw configuration, produce samples with consistent appearance and melt flow characteristics. Tensile ductility/toughness and impact toughness are enhanced by up to 11‐fold as compared to the as‐received sample, to a level near and above those of an equivalent virgin HDPE. Calorimetry, optical microscopy, X‐ray scattering, and rheology characterization reveal that the mechanical improvements result from a favorable combination of physical and molecular changes in rHDPE, such as impurity size reduction, spherulite size enlargement, and chain branching. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43070.
Optimal individualized dosing strategies: A pharmacologic approach to developing dynamic treatment regimens for continuous‐valued treatments
Authors: Rich Benjamin , Moodie Erica E. M. , Stephens David A.
Published: November 2015

There have been considerable advances in the methodology for estimating dynamic treatment regimens, and for the design of sequential trials that can be used to collect unconfounded data to inform such regimens. However, relatively little attention has been paid to how such methodology could be used to advance understanding of optimal treatment strategies in a continuous dose setting, even though it is often the case that considerable patient heterogeneity in drug response along with a narrow therapeutic window may necessitate the tailoring of dosing over time. Such is the case with warfarin, a common oral anticoagulant. We propose novel, realistic simulation models based on pharmacokinetic‐pharmacodynamic properties of the drug that can be used to evaluate potentially optimal dosing strategies. Our results suggest that this methodology can lead to a dosing strategy that performs well both within and across populations with different pharmacokinetic characteristics, and may assist in the design of randomized trials by narrowing the list of potential dosing strategies to those which are most promising.
Metabolomics for undergraduates: Identification and pathway assignment of mitochondrial metabolites
Authors: Marques Ana Patrícia , Serralheiro Maria Luisa , Ferreira António E.N. , Freire Ana Ponces , Cordeiro Carlos , Silva Marta Sousa
Published: November 2015

Metabolomics is a key discipline in systems biology, together with genomics, transcriptomics, and proteomics. In this omics cascade, the metabolome represents the biochemical products that arise from cellular processes and is often regarded as the final response of a biological system to environmental or genetic changes. The overall screening approach to identify all the metabolites in a given biological system is called metabolic fingerprinting. Using high‐resolution and high‐mass accuracy mass spectrometry, large metabolome coverage, sensitivity, and specificity can be attained. Although the theoretical concepts of this methodology are usually provided in life‐science programs, hands‐on laboratory experiments are not usually accessible to undergraduate students. Even if the instruments are available, there are not simple laboratory protocols created specifically for teaching metabolomics. We designed a straightforward hands‐on laboratory experiment to introduce students to this methodology, relating it to biochemical knowledge through metabolic pathway mapping of the identified metabolites. This study focuses on mitochondrial metabolomics since mitochondria have a well‐known, medium‐sized cellular sub‐metabolome. These features facilitate both data processing and pathway mapping. In this experiment, students isolate mitochondria from potatoes, extract the metabolites, and analyze them by high‐resolution mass spectrometry (using an FT‐ICR mass spectrometer). The resulting mass list is submitted to an online program for metabolite identification, and compounds associated with mitochondrial pathways can be highlighted in a metabolic network map. © 2015 by The International Union of Biochemistry and Molecular Biology, 44:38–54, 2016.
Catalytic Depolymerization of Chitin with Retention of N‐Acetyl Group
Authors: Yabushita Mizuho , Kobayashi Hirokazu , Kuroki Kyoichi , Ito Shogo , Fukuoka Atsushi
Published: November 2015

Chitin, a polymer of N‐acetylglucosamine units with β‐1,4‐glycosidic linkages, is the most abundant marine biomass. Chitin monomers containing N‐acetyl groups are useful precursors to various fine chemicals and medicines. However, the selective conversion of robust chitin to N‐acetylated monomers currently requires a large excess of acid or a long reaction time, which limits its application. We demonstrate a fast catalytic transformation of chitin to monomers with retention of N‐acetyl groups by combining mechanochemistry and homogeneous catalysis. Mechanical‐force‐assisted depolymerization of chitin with a catalytic amount of H2SO4 gave soluble short‐chain oligomers. Subsequent hydrolysis of the ball‐milled sample provided N‐acetylglucosamine in 53 % yield, and methanolysis afforded 1‐O‐methyl‐N‐acetylglucosamine in yields of up to 70 %. Our process can greatly reduce the use of acid compared to the conventional process.
Multi‐interface cognitive radio for enhanced routing in multi‐hop cellular networks
Authors: Thomas Ginu , Seet Boon‐Chong
Published: November 2015

Multi‐hop cellular network (MCN) is a wireless communication architecture that combines the benefits of conventional single‐hop cellular networks and multi‐hop ad hoc relaying networks. The route selection in MCN depends on the availability of intermediate nodes and their neighborhood connectivity. Cognitive radio (CR) is an emerging communication paradigm that exploits the available radio frequencies opportunistically for the effective utilization of the radio frequency spectrum. The incorporation of CR and mobile ad hoc network routing protocols in MCN could potentially improve the spectrum utilization and the routing performance of MCN. This paper firstly presents the proposed model for the multi‐interface CR mobile node with transceiver synchronization and then investigates its opportunistic spectrum utilization and routing performance in MCN. Copyright © 2015 John Wiley & Sons, Ltd.
Optimization of a nano‐enzymatic reactor for on‐line tryptic digestion of polypeptide conjugates by capillary electrophoresis
Authors: Ladner Yoann , Coussot Gaelle , Ebner Stefanie , Ibrahim Amal , Vidal Laetitia , Perrin Catherine
Published: November 2015

This work aims at studying the optimization of an on‐line capillary electrophoresis (CE)‐based tryptic digestion methodology for the analysis of therapeutic polypeptides (PP). With this methodology, a mixture of surrogate peptide fragments and amino acid were produced on‐line by trypsin cleavage (enzymatic digestion) and subsequently analyzed using the same capillary. The resulting automation of all steps such as injection, mixing, incubation, separation and detection minimizes the possible errors and saves experimental time. In this paper, we first study the differents parameters influencing PP cleavage inside the capillary (plug length, reactant concentration, incubation time, diffusion and electrophoretic plugs mixing). In a second part, the optimization of the electrophoretic separation conditions of generated hydrolysis products (nature, pH and ionic strength (I) of the background electrolyte (BGE)) is described. Using the optimized conditions, excellent repeatability was obtained in terms of separation (migration times) and proteolysis (number of products from enzymatic hydrolysis and corresponding amounts) demonstrating the robustness of the proposed methodology.
Predicting Stock Return Volatility: Can We Benefit from Regression Models for Return Intervals?
Authors: Fischer Henning , Blanco‐FERNÁndez Ángela , Winker Peter
Published: November 2015

We study the performance of recently developed linear regression models for interval data when it comes to forecasting the uncertainty surrounding future stock returns. These interval data models use easy‐to‐compute daily return intervals during the modeling, estimation and forecasting stage. They have to stand up to comparable point‐data models of the well‐known capital asset pricing model type—which employ single daily returns based on successive closing prices and might allow for GARCH effects—in a comprehensive out‐of‐sample forecasting competition. The latter comprises roughly 1000 daily observations on all 30 stocks that constitute the DAX, Germany's main stock index, for a period covering both the calm market phase before and the more turbulent times during the recent financial crisis. The interval data models clearly outperform simple random walk benchmarks as well as the point‐data competitors in the great majority of cases. This result does not only hold when one‐day‐ahead forecasts of the conditional variance are considered, but is even more evident when the focus is on forecasting the width or the exact location of the next day's return interval. Regression models based on interval arithmetic thus prove to be a promising alternative to established point‐data volatility forecasting tools. Copyright ©2015 John Wiley & Sons, Ltd.
Conjugate margin pattern of the Southwest Sub‐basin, South China Sea: insights from deformation structures in the continent‐ocean transition zone
Authors: Ding Weiwei , Li Jiabiao
Published: November 2015

Eight cross‐sections from the continent‐ocean transition zone of the Southwest Sub‐basin, South China Sea, have been used to compare conjugate rifted margins that are typical of magma‐poor rift systems. The geological timing of the break‐up unconformity in the continental margins shows that the Reed Bank and the Dangerous Grounds in the south continental margin connect with the Zhongsha Islands and the western Phu Khanh Basin, which experienced northwest‐southeast oriented movement after the opening of the Southwest Sub‐basin. Detailed interpretations identify a range of deformational and sedimentary features in the continent‐ocean transition zones with and without rigid blocks. Remarkable structural similarities appear in the transition zone lying within the convex‐shaped area shaped by rigid blocks of the conjugate margin (e.g. the Zhongsha Islands and the Reed Bank) or within concave‐shaped areas sandwiched by rigid blocks. Rigid tectonic blocks such as the Zhongsha Islands and the Reed Bank played important roles in both the shaping of the continent‐ocean boundary and the initial continental break‐up. Copyright © 2015 John Wiley & Sons, Ltd.
The “silent” imprint of musical training
Authors: Klein Carina , Liem Franziskus , Hänggi Jürgen , Elmer Stefan , Jäncke Lutz
Published: November 2015

Playing a musical instrument at a professional level is a complex multimodal task requiring information integration between different brain regions supporting auditory, somatosensory, motor, and cognitive functions. These kinds of task‐specific activations are known to have a profound influence on both the functional and structural architecture of the human brain. However, until now, it is widely unknown whether this specific imprint of musical practice can still be detected during rest when no musical instrument is used. Therefore, we applied high‐density electroencephalography and evaluated whole‐brain functional connectivity as well as small‐world topologies (i.e., node degree) during resting state in a sample of 15 professional musicians and 15 nonmusicians. As expected, musicians demonstrate increased intra‐ and interhemispheric functional connectivity between those brain regions that are typically involved in music perception and production, such as the auditory, the sensorimotor, and prefrontal cortex as well as Broca's area. In addition, mean connectivity within this specific network was positively related to musical skill and the total number of training hours. Thus, we conclude that musical training distinctively shapes intrinsic functional network characteristics in such a manner that its signature can still be detected during a task‐free condition. Hum Brain Mapp 37:536–546, 2016. © 2015 Wiley Periodicals, Inc.
Synthesis, Spectroscopic Studies of Fluorinated Pyrimido‐1,2,4‐Triazines: Protective Effect Against Some Plant Pathogenic Fungi
Authors: Aqlan Faisal M. S. , Makki Mohammed S. T. , Abdel‐Rahman Rada M.
Published: November 2015

In search for new biologically active compounds, several new fluorine‐substituted pyrimido [2,3‐c][1,2,4]triazino (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16) have been synthesized via the nucleophilic attack of 2‐hydrazinopyrimidinone (2) toward more positive carbons under different conditions. Structure of the newly synthesized compounds was deduced from elemental analyses as well as their spectral data (UV, IR, NMR, and M/S). The antifungal activity of the target ring systems has been evaluated both in vitro and in vivo against some phytopathogenic fungi associated with wheat grains. Result showed that compounds 6, 7, and 8 have high protection of wheat grains against the fungal infection.
Human T‐Lymphotropic Virus Type 1 and 2 Seroprevalence among first‐time blood donors in Chile, 2011–2013
Authors: San Martín Héctor , Balanda Monserrat , Vergara Nicolás , Valenzuela María Antonieta , Cartier Luis , Ayala Salvador , Ramírez Eugenio
Published: November 2015

Infection with human T‐lymphotropic virus type 1/2 (HTLV‐1/2) is a major health problem. HTLV‐1/2 infection is endemic in Chile but representative donor prevalence data are lacking. Data on all blood donors in a large network of Chilean blood centers were examined during 2011–2013. Screening of HTLV‐1/2 antibodies were measured by enzyme immunoassay (EIA) at all blood banks. Blood samples with anticoagulants from initially reactive blood donors were analyzed by serological confirmation tests (immunofluorescence or recombinant immunoblot) at the HTLV National Reference Laboratory of the Public Health Institute of Chile. Additionally, detection of HTLV‐1 and HTLV‐2 provirus in peripheral blood mononuclear cells (PBMCs) was performed in all blood donors as confirmatory test. Prevalence rates were calculated. Among 694,016 donors, 706 were seropositive for HTLV‐1 (prevalence, 1.02 cases per 1,000; 95% confidence interval [CI], 0.94–1.09), and 97 were seropositive for HTLV‐2 (prevalence, 0.14 cases per 1,000; 95%CI, 0.11–0.17). Prevalence of HTLV‐1 differed considerably by region, from 0.51 to 1.69 per 1,000. Prevalence of HTLV‐2 was similar across the country (0.12–0.16). HTLV‐1 prevalence was associated with female sex, older age, and residence in the north of Chile. HTVL‐2 prevalence was associated with older age. The HTLV‐1 prevalence among Chilean blood donors was relatively high and could be reduced by improving donor recruitment and selection in high prevalence areas. Blood center data may contribute to surveillance for HTLV‐1 and HTLV‐2 infections. J. Med. Virol. 88:1067–1075, 2016. © 2015 Wiley Periodicals, Inc.
Viele Quellen anzapfen
Authors: Dworschak Dominik , Tesch Silke , Böhme Uwe
Published: November 2015

Dass eine Suche mit Google für eine wissenschaftliche Literaturrecherche nicht genügt, hat sich inzwischen herumgesprochen. Aber es reicht häufig nicht, in nur einer Datenbank zu suchen — so gut sie auch sein mag.
Social Return on Investment Analysis
Authors: Walk Marlene , Greenspan Itay , Crossley Honey , Handy Femida
Published: November 2015

This article uses a social return on investment (SROI) methodology to analyze the social impact of a social enterprise offering a job and skills training program to an unemployed, largely female population. The social enterprise is based in Toronto (Canada) and run by a nonprofit agency dedicated to the advancement and empowerment of women, primarily immigrants, through access to employment. We focus our analysis on a job and skills training program that provides clients with the skills and tools that they need to successfully seek employment in their efforts to (re‐)enter the Canadian labor market. Our goal is to determine the tangible and intangible program outcomes by applying and testing the SROI methodology.
Effect of poly (lactic acid)‐graft‐glycidyl methacrylate as a compatibilizer on properties of poly (lactic acid)/banana fiber biocomposites
Authors: VP Sajna , Mohanty Smita , Nayak Sanjay K.
Published: November 2015

The main aim of this study was to synthesis of poly (lactic acid) (PLA)‐graft‐glycidyl methacrylate (GMA) as well as its influence on the properties of PLA/banana fiber biocomposites. PLA‐graft‐GMA graft copolymer (GC) was synthesized by melt blending PLA with GMA using benzoyl peroxide and dicumyl peroxide as initiators. Graft copolymerization was confirmed by FTIR and 1H‐NMR spectroscopic studies. PLA/silane treated banana fiber (SiB) biocomposites with various GC concentrations were prepared by melt blending followed by injection molding techniques. The influence of GC content on the mechanical, thermal and moisture resistance properties of the composite was investigated. The addition of 15 wt% GC content in the biocomposite provided optimum tensile and flexural strength, which is attributed to the greater compatibility between fiber and PLA matrix. The thermal properties of biocomposites have been evaluated using thermogravimetric analysis which provided evidence of improved interfacial adhesion between SiB and PLA by the addition of GC. Additionally, GC enhanced the moisture absorption resistance of biocomposites. These results indicated that GC is indeed a good candidate as a compatibilizing agent to improve the compatibility in PLA/fiber biocomposites. Copyright © 2015 John Wiley & Sons, Ltd.
Fabrication of Cu@MxOy (M = Cu, Mn, Co, Fe) Nanocable Arrays for Lithium‐Ion Batteries with Long Cycle Lives and High Rate Capabilities
Authors: He Tianou , Qin Xingtai , Yang Guang , Jin Mingshang
Published: November 2015

A new strategy is reported to fabricate Cu@MxOy (M = Cu, Mn, Co, Fe) nanocable arrays using five‐fold twinned copper (Cu) nanowire (NW) arrays as starting materials, to promote both the cycling stability and high rate capability of MxOy as anodes for LIBs. Conductive Cu NW arrays were synthesized on Cu foil via chemical vapor deposition (CVD), followed by the oxidation of their surface so as to form Cu@Cu2O nanocable arrays. The thickness of the active material (Cu2O) on the Cu NW arrays can be tuned from 20 nm to 160 nm by simply controlling the oxidation time. Based on this accurate control, the optimal coating thickness of Cu2O was determined to be around 35 nm. Additionally, the Cu2O active material shell can be easily transformed to other metal oxides with even higher specific capacities via a “coordinating etching” strategy based on Pearson's principle, resulting in Cu@MxOy nanocable arrays (M = Mn, Co, Fe). When applied as electrodes for LIBs, these 3D electrodes show long cycle lives (over 300 cycles) and high rate capabilities.
Sensitivity analyses for partially observed recurrent event data
Authors: Akacha Mouna , Ogundimu Emmanuel O.
Published: November 2015

Recurrent events involve the occurrences of the same type of event repeatedly over time and are commonly encountered in longitudinal studies. Examples include seizures in epileptic studies or occurrence of cancer tumors. In such studies, interest lies in the number of events that occur over a fixed period of time. One considerable challenge in analyzing such data arises when a large proportion of patients discontinues before the end of the study, for example, because of adverse events, leading to partially observed data. In this situation, data are often modeled using a negative binomial distribution with time‐in‐study as offset. Such an analysis assumes that data are missing at random (MAR). As we cannot test the adequacy of MAR, sensitivity analyses that assess the robustness of conclusions across a range of different assumptions need to be performed.

Sophisticated sensitivity analyses for continuous data are being frequently performed. However, this is less the case for recurrent event or count data. We will present a flexible approach to perform clinically interpretable sensitivity analyses for recurrent event data. Our approach fits into the framework of reference‐based imputations, where information from reference arms can be borrowed to impute post‐discontinuation data. Different assumptions about the future behavior of dropouts dependent on reasons for dropout and received treatment can be made. The imputation model is based on a flexible model that allows for time‐varying baseline intensities. We assess the performance in a simulation study and provide an illustration with a clinical trial in patients who suffer from bladder cancer. Copyright © 2015 John Wiley & Sons, Ltd.
An enhanced ensemble‐based method for computing CNOPs using an efficient localization implementation scheme and a two‐step optimization strategy: formulation and preliminary tests
Authors: Tian Xiangjun , Feng Xiaobing , Zhang Hongqin , Zhang Bin , Han Rui
Published: November 2015

The ensemble‐based methods for computing conditional nonlinear optimal perturbations (CNOPs) often contain a localization implementation scheme; its computer implementation is very expensive because of huge memory usage or costly repeated calculations. As a result, the lack of efficient algorithms limits the applications of CNOP. To address this issue, an efficient new localization implementation scheme is proposed in this article. The main ideas are to utilize the correlation matrix and to approximate it by a set of selected Gaussian random samples. An enhanced ensemble‐based method is then proposed using the new localization scheme and a newly proposed two‐step optimization strategy. The proposed approach results in a significant speed‐up for overall optimization algorithms for computing the CNOPs and can be applied to complicated nonlinear models. Numerical experiments with a nonlinear model of the viscous Burgers equation show that the proposed new method produces comparable solutions against an existing ensemble‐based method and an adjoint‐based one for computing the CNOPs. In terms of the net growth ratio of norm square, the proposed method slightly outperforms these two existing methods. On the other hand, our numerical experiments show that the proposed method has an advantage on the memory usage and computational cost, which particularly demonstrates its high potential in predictability or sensitivity studies of operational prediction models. Another group of assimilation experiments conducted using the T21L3 quasi‐geostrophic (QG) model further demonstrates its potential for broader applications.
The effects of cavity‐filling techniques on microleakage in class II resin restorations prepared with Er:YAG laser and diamond bur: A scanning electron microscopy study
Authors: Ozel Emre , Tuna Elif Bahar , Firatli Erhan
Published: November 2015

The purpose of this study was to investigate how two cavity‐filling techniques affect microleakage in class II resin restorations prepared with Er:YAG laser and diamond bur. Standard MO and DO cavities were prepared in 20 extracted third molars, each randomly assigned to either Group‐1 [Herculite XRV Ultra‐bur‐prepared cavity(bp)], Group‐2 [Herculite XRV Ultra‐laser‐prepared cavity(lp)], Group‐3 (SonicFill‐(bp)], or Group‐4 [SonicFill‐(lp)]. For Groups 2 and 4, cavities were prepared by using an Er:YAG laser with a wavelength of 2.94 μm, output power of 200 mJ/pulse, and repetition rate of 20Hz. Teeth were restored with a one‐step, self‐etch adhesive material (OptiBond All‐in‐One), a nanohybrid composite (Herculite XRV Ultra), and a bulk‐fill composite (SonicFill) according to the manufacturer's instructions. Five teeth from each group were chosen for microleakage investigation and two teeth for scanning electron microscope evaluation. Statistical analysis was performed by using Kruskal–Wallis test. Pair‐wise comparisons were performed by Mann–Whitney U test with Bonferroni correction (p < 0.05). The statistical analysis of data revealed greater microleakage in cervical versus occlusal regions in all groups (P < 0.05). Group‐2 yielded a higher degree of marginal leakage than Group‐3 in terms of occlusal surfaces (p < 0.05). For cervical regions, a statistically significant difference was observed between Groups 2 and 3 as well as Groups 2 and 4 (p < 0.05). Group‐3 exhibited significantly better marginal sealing than Group‐1 in the cervical region (p < 0.05). The cavities prepared using an Er:YAG laser showed greater microleakage than those conventionally prepared using burs regardless of restorative material at both occlusal and cervical margins. SCANNING 38:389–395, 2016. © 2015 Wiley Periodicals, Inc.