bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion‐Scale Wave Properties and Enhanced Ion Heating Across the Low‐Latitude Boundary Layer During Kelvin‐Helmholtz Instability
Authors: Moore T. W. , Nykyri K. , Dimmock A. P.
Published: September 2017

In the Earth's magnetosphere, the magnetotail plasma sheet ions are much hotter than in the shocked solar wind. On the dawn sector, the cold‐component ions are more abundant and hotter by 30–40% when compared to the dusk sector. Recent statistical studies of the flank magnetopause and magnetosheath have shown that the level of temperature asymmetry of the magnetosheath is unable to account for this, so additional physical mechanisms must be at play, either at the magnetopause or plasma sheet that contributes to this asymmetry. In this study, we perform a statistical analysis on the ion‐scale wave properties in the three main plasma regimes common to flank magnetopause boundary crossings when the boundary is unstable to Kelvin‐Helmholtz instability (KHI): hot and tenuous magnetospheric, cold and dense magnetosheath, and mixed (Hasegawa et al., 2004). These statistics of ion‐scale wave properties are compared to observations of fast magnetosonic wave modes that have recently been linked to Kelvin‐Helmholtz (KH) vortex centered ion heating (Moore et al., 2016). The statistical analysis shows that during KH events there is enhanced nonadiabatic heating calculated during ion scale wave intervals when compared to non‐KH events. This suggests that during KH events there is more free energy for ion‐scale wave generation, which in turn can heat ions more effectively when compared to cases when KH waves are absent. This may contribute to the dawn favored temperature asymmetry of the plasma sheet; recent studies suggest KH waves favor the dawn flank during Parker‐Spiral interplanetary magnetic field.
Study of Volcanic Activity at Different Time Scales Using Hypertemporal Land Surface Temperature Data
Authors: Pavlidou Efthymia , Hecker Christoph , van der Werff Harald , van der Meijde Mark
Published: September 2017

We apply a method for detecting subtle spatiotemporal signal fluctuations to monitor volcanic activity. Whereas midwave infrared data are commonly used for volcanic hot spot detection, our approach utilizes hypertemporal longwave infrared‐based land surface temperature (LST) data. Using LST data of the second‐generation European Meteorological Satellites, we study (a) a paroxysmal, 1 day long eruption of Mount Etna (Italy); (b) a prolonged, 6 month period of effusive and lateral lava flows of the Nyamuragira volcano (Democratic Republic of Congo); and (c) intermittent activity in the permanent lava lake of Nyiragongo (Democratic Republic of Congo) over a period of 2 years (2011–2012). We compare our analysis with published ground‐based observations and satellite‐based alert systems; results agree on the periods of increased volcanic activity and quiescence. We further apply our analysis on mid‐infrared and long‐infrared brightness temperatures and compare the results. We conclude that our study enables the use of LST data for monitoring volcanic dynamics at different time scales, can complement existing methodologies, and allows for use of long time series from older sensors that do not provide midwave infrared data.
Distal Enhanced Sedimentation From Volcanic Plumes: Insights From the Secondary Mass Maxima in the 1992 Mount Spurr Fallout Deposits
Authors: Eychenne Julia , Rust Alison C. , Cashman Katharine V. , Wobrock Wolfram
Published: September 2017

Some tephra fallout deposits show an increase of mass and thickness at distances from the source >100 km (areas of secondary mass maximum, ASMM) which demonstrates distal enhanced sedimentation from volcanic plumes. We explore development of the ASMMs during the 1992 August and September Mount Spurr eruptions, USA, by combining field data on the spatial distribution of mass and grain size with (1) simulations of individual particle settling through a homogeneous and horizontally stratified atmosphere and (2) mesoscale models of the three‐dimensional wind field that include the effect of the underlying topography. The crosswind and downwind variations of deposit characteristics indicate that the increase of sedimentation at the ASMMs is not formed solely because of preferential settling of small ash particles (<125 μm), as commonly assumed in aggregation models. Instead, ASMM grain sizes correspond to the fine modes of the bimodal total grain size distributions. There also appears to be a link between the ASMM and the topography: the mass local minima occur across the windward flank of 2 km high mountain ranges, while the ASMMs spread on the leeward flank. Mesoscale models of the three‐dimensional wind field show vertical oscillations in the wind over mountainous regions which may enhance mechanisms of en masse sedimentation (aggregation, hydrometeor formation, and particle boundary layers), as well as strong spatial variations of the horizontal wind field in the lower troposphere. Our study demonstrates the importance of using grain size, as well as mass, data to constrain the complex processes responsible for particle sedimentation from volcanic plumes.
A Geomagnetic Paleointensity Record of 0.6 to 3.2 Ma From Sediments in the Western Equatorial Pacific and Remanent Magnetization Lock‐In Depth
Authors: Sakuramoto Yukihiro , Yamazaki Toshitsugu , Kimoto Katsunori , Miyairi Yosuke , Kuroda Junichiro , Yokoyama Yusuke , Matsuzaki Hiroyuki
Published: September 2017

Information of past geomagnetic intensity variations is important for better understanding of the geodynamo, and efforts to recover continuous paleointensity records continue, in particular for ages older than 2 Ma. In this study, a new relative paleointensity (RPI) record of 0.6 to 3.2 Ma was obtained from a sediment core in the western equatorial Pacific, which has good age control by the oxygen isotope stratigraphy from 2.0 to 3.2 Ma. The RPI record could well be correlated to existing RPI templates despite the low sedimentation rate of ~5 m/Ma and will be useful for future construction of a stacked paleointensity curve beyond 2 Ma. Magnetic minerals of the core consist mainly of biogenic and terrigenous oxidized magnetite. Some rock magnetic contamination to long‐term RPI changes is recognized; RPI inversely correlates with the ratio of anhysteretic remanent magnetization to saturation remanent magnetization, which may be caused by differences in remanence acquisition efficiency between the biogenic and terrigenous magnetic components. The lock‐in depth of the studied core is estimated to be approximately 0 from a line of evidence including no apparent offset between RPI and cosmogenic beryllium nuclide flux changes across some polarity boundaries. Lock‐in depths vary locally from core to core or even within a single core and have no obvious relation with sedimentation rates and carbonate contents. Lock‐in depths may be controlled by factors that are currently difficult to be evaluated, such as variations in sediment flocculation sizes and biogeochemical remanent magnetization dependent to chemical conditions of sediments.
Remote‐Sensing Estimation of Phytoplankton Size Classes FromGOCISatellite Measurements in Bohai Sea and Yellow Sea
Authors: Sun Deyong , Huan Yu , Qiu Zhongfeng , Hu Chuanmin , Wang Shengqiang , He Yijun
Published: September 2017

Phytoplankton size class (PSC), a measure of different phytoplankton functional and structural groups, is a key parameter to the understanding of many marine ecological and biogeochemical processes. In turbid waters where optical properties may be influenced by terrigenous discharge and nonphytoplankton water constituents, remote estimation of PSC is still a challenging task. Here based on measurements of phytoplankton diagnostic pigments, total chlorophylla, and spectral reflectance in turbid waters of Bohai Sea and Yellow Sea during summer 2015, a customized model is developed and validated to estimate PSC in the two semienclosed seas. Five diagnostic pigments determined through high‐performance liquid chromatography (HPLC) measurements are first used to produce weighting factors to model phytoplankton biomass (using total chlorophyllaas a surrogate) with relatively high accuracies. Then, a common method used to calculate contributions of microphytoplankton, nanophytoplankton, and picophytoplankton to the phytoplankton assemblage (i.e.,Fm,Fn, andFp) is customized using local HPLC and other data. Exponential functions are tuned to model the size‐specific chlorophyllaconcentrations (Cm,Cn, andCpfor microphytoplankton, nanophytoplankton, and picophytoplankton, respectively) with remote‐sensing reflectance (Rrs) and total chlorophyllaas the model inputs. Such a PSC model shows two improvements over previous models: (1) a practical strategy (i.e., modelCpandCnfirst, and then deriveCmasC‐Cp‐Cn) with an optimized spectral band (680 nm) forRrsas the model input; (2) local parameterization, including a local chlorophyllaalgorithm. The performance of the PSC model is validated using in situ data that were not used in the model development. Application of the PSC model to GOCI (Geostationary Ocean Color Imager) data leads to spatial and temporal distribution patterns of phytoplankton size classes (PSCs) that are consistent with results reported from field measurements by other researchers. While the applicability of the PSC model together with its parameterization to other optically complex regions and to other seasons is unknown, the findings of this study suggest that the approach to develop such a model may be extendable to other cases as long as local data are used to select the optimal band and to determine the model coefficients.
Uncertainty in Predicting CCN Activity of Aged and Primary Aerosols
Authors: Zhang Fang , Wang Yuying , Peng Jianfei , Ren Jingye , Collins Don , Zhang Renyi , Sun Yele , Yang Xin , Li Zhanqing
Published: September 2017

Understanding particle CCN activity in diverse atmospheres is crucial when evaluating aerosol indirect effects. Here aerosols measured at three sites in China were categorized as different types for attributing uncertainties in CCN prediction in terms of a comprehensive data set including size‐resolved CCN activity, size‐resolved hygroscopic growth factor, and chemical composition. We show that CCN activity for aged aerosols is unexpectedly underestimated ~22% at a supersaturation (S) of 0.2% when using κ‐Kohler theory with an assumption of an internal mixture with measured bulk composition that has typically resulted in an overestimate of the CCN activity in previous studies. We conclude that the underestimation stems from neglect of the effect of aging/coating on particle hygroscopicity, which is not considered properly in most current models. This effect enhanced the hygroscopicity parameter (κ) by between ~11% (polluted conditions) and 30% (clean days), as indicated in diurnal cycles of κ based on measurements by different instruments. In the urban Beijing atmosphere heavily influenced by fresh emissions, the CCN activity was overestimated by 45% at S = 0.2%, likely because of inaccurate assumptions of particle mixing state and because of variability of chemical composition over the particle size range. For both fresh and aged aerosols, CCN prediction exhibits very limited sensitivity to κSOA, implying a critical role of other factors like mixing of aerosol components within and between particles in regulating CCN activity. Our findings could help improving CCN parameterization in climate models.
Heat Waves in China: Definitions, Leading Patterns, and Connections to Large‐Scale Atmospheric Circulation and SSTs
Authors: Wang Pinya , Tang Jianping , Sun Xuguang , Wang Shuyu , Wu Jian , Dong Xinning , Fang Juan
Published: September 2017

Based on the daily maximum temperatures (Tmax) from 587 surface observation stations in China during 1959–2013, heat waves are detected using both absolute and relative definitions. The spatiotemporal variations of heat wave occurrence/duration/amplitude are compared between the two definitions. Considering the significant differences in regional climatology, relative threshold is more meaningful to detect the local extremes. By utilizing the empirical orthogonal function, the integral index heat wave total intensity is decomposed into three dominant modes: interdecadal (ID), interannual‐tripole (IA‐TR), and interannual‐dipole (IA‐DP) modes. The ID mode shows uniform anomalies over the whole China, with the maximum in north, and its corresponding time series depict notable interdecadal variations with a turning point around mid‐1990s. The IA‐DP mode exhibits opposite‐signed anomalies over north and south China. The IA‐TR mode shows an anomalous tripole pattern with negative anomalies over central China and positive anomalies over north and south China in its positive phase. Both the IA‐DP and IA‐TR patterns are more obvious since mid‐1990s with mainly year‐to‐year variations before that. All the three modes are controlled by anomalous high‐pressure systems, which are accompanied by local‐scale dry land conditions. The diabatic heating associated with anomalous convective activities over tropical western Pacific triggers Rossby wave trains propagating northward along the East Asia, which causes abnormal heat waves through descending motion over the high‐pressure nodes. In turn, the severe convections are generated by enhanced Walker circulation in the tropical Pacific due to warming and/or cooling sea surface temperature (SST) anomalies in the tropical western and eastern Pacific, respectively.
Modeling C1–C4 Alkyl Nitrate Photochemistry and Their Impacts on O3 Production in Urban and Suburban Environments of Hong Kong
Authors: Lyu X. P. , Guo H. , Wang N. , Simpson I. J. , Cheng H. R. , Zeng L. W. , Saunders S. M. , Lam S. H. M. , Meinardi S. , Blake D. R.
Published: September 2017

As intermediate products of photochemical reactions, alkyl nitrates (RONO2) regulate ozone (O3) formation. In this study, a photochemical box model incorporating master chemical mechanism well reproduced the observed RONO2 at an urban and a mountainous site, with index of agreement in the range of 0.66–0.73. The value 0.0003 was identified to be the most appropriate branching ratio for C1 RONO2, with the error less than 50%. Although levels of the parent hydrocarbons and nitric oxide (NO) were significantly higher at the urban site than the mountainous site, the production of C2–C3 RONO2 was comparable to or even lower than at the mountainous site, due to the lower concentrations of oxidative radicals in the urban environment. Based on the profiles of air pollutants at the mountainous site, the formation of C2–C4 RONO2 was limited by NOx (volatile organic compounds (VOCs)) when total volatile organic compounds (TVOCs)/NOx was higher (lower) than 10.0 ± 0.4 parts per billion by volume (ppbv)/ppbv. This dividing ratio decreased (p < 0.05) to 8.7 ± 0.4 ppbv/ppbv at the urban site, mainly due to the different air pollutant profiles at the two sites. For the formation of C1 RONO2, the NOx‐limited regime extended the ratio of TVOCs/NOx to as low as 2.4 ± 0.2 and 3.1 ± 0.1 ppbv/ppbv at the mountainous and urban site, respectively. RONO2 formation led to a decrease of simulated O3, with reduction efficiencies (O3 reduction/RONO2 production) of 4–5 parts per trillion by volume (pptv)/pptv at the mountainous site and 3–4 pptv/pptv at the urban site. On the other hand, the variations of simulated O3 induced by RONO2 degradation depended upon the regimes controlling O3 formation and the relative abundances of TVOCs and NOx.
Botulinum toxin treatment for hypersalivation in anti‐NMDA receptor encephalitis
Authors: Jun Jin‐Sun , Seo Han Gil , Lee Soon‐Tae , Chu Kon , Lee Sang Kun
Published: September 2017

Hypersalivation is one of the intractable symptoms of anti‐N‐methyl‐d‐aspartate receptor (NMDAR) encephalitis. While anticholinergic medications partially improve the hypersalivation, they can aggravate the autonomic dysfunctions associated with anti‐NMDAR encephalitis. Thus, we investigated the efficacy and safety of botulinum toxin type A injection on hypersalivation refractory to anticholinergics in six patients with anti‐NMDAR encephalitis. Hypersalivation was well‐controlled without remarkable adverse reaction over 16 weeks after botulinum toxin type A, although two patients were reinjected at 12 weeks due to reaggravation of hypersalivation. Our findings suggest that botulinum toxin type A might be a better choice than anticholinergics for management of hypersalivation in patients with anti‐NMDAR encephalitis.
Colloidal Stability and Surface Chemistry Are Key Factors for the Composition of the Protein Corona of Inorganic Gold Nanoparticles
Authors: Johnston Blair D. , Kreyling Wolfgang G. , Pfeiffer Christian , Schäffler Martin , Sarioglu Hakan , Ristig Simon , Hirn Stephanie , Haberl Nadine , Thalhammer Stefan , Hauck Stefanie M. , Semmler‐Behnke Manuela , Epple Matthias , Hühn Jonas , Del Pino Pablo , Parak Wolfgang J.
Published: September 2017

To study the influence of colloidal stability on protein corona formation, gold nanoparticles are synthesized with five distinct surface modifications: coating with citric acid, bis(p‐sulfonatophenyl)phenylphosphine dihydrate dipotassium salt, thiol‐terminated methoxy‐polyethylene glycol, dodecylamine‐grafted poly(isobutylene‐alt‐maleic anhydride), and dodecylamine‐grafted poly(isobutylene‐alt‐maleic anhydride) conjugated with polyethylene glycol. The nanoparticles are incubated with serum or bronchoalveolar lavage fluid from C57BL/6 mice (15 min or 24 h) to assess the effect of differential nanoparticle surface presentation on protein corona formation in the air–blood barrier exposure pathway. Proteomic quantification and nanoparticle size measurements are used to assess protein corona formation. We show that surface modification has a clear effect on the size and the composition of the protein corona that is related to the colloidal stability of the studied nanoparticles. Additionally, differences in the composition and size of the protein corona are shown between biological media and duration of exposure, indicating evolution of the corona through this exposure pathway. Consequently, a major determinant of protein corona formation is the colloidal stability of nanoparticles in biological media and chemical or environmental modification of the nanoparticles alters the surface presentation of the functional epitope in vivo. Therefore, the colloidal stability of nanoparticles has a decisive influence on nano–bio interactions.
A High‐On/Off‐Ratio Floating‐Gate Memristor Array on a Flexible Substrate via CVD‐Grown Large‐Area 2D Layer Stacking
Authors: Vu Quoc An , Kim Hyun , Nguyen Van Luan , Won Ui Yeon , Adhikari Subash , Kim Kunnyun , Lee Young Hee , Yu Woo Jong
Published: September 2017

Memristors such as phase‐change memory and resistive memory have been proposed to emulate the synaptic activities in neuromorphic systems. However, the low reliability of these types of memories is their biggest challenge for commercialization. Here, a highly reliable memristor array using floating‐gate memory operated by two terminals (source and drain) using van der Waals layered materials is demonstrated. Centimeter‐scale samples (1.5 cm × 1.5 cm) of MoS2 as a channel and graphene as a trap layer grown by chemical vapor deposition (CVD) are used for array fabrication with Al2O3 as the tunneling barrier. With regard to the memory characteristics, 93% of the devices exhibit an on/off ratio of over 103 with an average ratio of 104. The high on/off ratio and reliable endurance in the devices allow stable 6‐level memory applications. The devices also exhibit excellent memory durability over 8000 cycles with a negligible shift in the threshold voltage and on‐current, which is a significant improvement over other types of memristors. In addition, the devices can be strained up to 1% by fabricating on a flexible substrate. This demonstration opens a practical route for next‐generation electronics with CVD‐grown van der Waals layered materials.
Concepts, Working Principles, and Applications of Coding and Programmable Metamaterials
Authors: Liu Shuo , Cui Tie Jun
Published: September 2017

As a digital version of metamaterials, coding and programmable metamaterials have experienced rapid development since they were initially proposed in 2014. Unlike conventional metamaterials that are characterized by the sophisticated effective medium theory, coding metamaterials are described in a much simpler manner with binary codes, which builds up a bridge between the physical world and the digital world. In this article, the development of coding and programmable metamaterials in the past three years is reviewed, focusing primarily on the basic concept, working principle, design method, fabrication, and experimental validation. First, reflection‐type and refraction‐type coding metamaterials, along with two bifunctional coding metamaterials, are presented in the microwave, terahertz, and acoustic regimes. Second, the digital convolution theorem and information entropy of coding metamaterials are introduced to demonstrate the strong connection between metamaterials and information science. Then, recent progresses on engineering realization of field‐programmable metamaterials are demonstrated, including the compensation technique of plane waves under point source illumination, and applications in single‐sensor single‐frequency imaging systems. Finally, future directions and potential applications are summarized, followed by discussions on major challenges encountered in the design and fabrication of programmable metamaterials at higher frequencies.
Practical Syntheses of Terrylene Chromophores from Naphthalene and Perylene Building Blocks
Authors: Uersfeld Daniel , Stappert Sebastian , Li Chen , Müllen Klaus
Published: September 2017

A facile and efficient method to synthesize terrylene imides, a unique class of chromophores, and their derivatives from commercially available naphthalene and perylene building blocks is reported. We developed an extremely efficient Suzuki/C−H‐arylation coupling cascade with Pd2(dba)3/PCy3 (dba=dibenzylidenacetone, Cy=cyclohexyl) as the catalyst and highly soluble naphthalene derivatives as starting materials. This efficiency allows purification via precipitation and crystallization, avoiding time‐consuming column chromatography. For the first time, the highly soluble 3,4,11,12‐terrylene tetraester was prepared in gram scale with yields up to 75% which thus becomes a versatile starting material for the synthesis of new terrylene derivatives. The presented method not only allows the synthesis of terrylene dyes and pigments, but also presents a route towards perylene and terrylene monoimides which is an advantageous simplification of previously reported synthetic procedures.

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A mesoscale model for diffusion and permeation of shale gas at geological depth
Authors: Tong Tiexin , Cao Dapeng
Published: September 2017

The demand on energy is rising and shale gas as an important unconventional energy resource has received worldwide attention. It has shown a significant effect on the world's energy structure after the commercial exploitation of shale gas in the United States. Understanding diffusion and permeation of shale gas at geological depths is quite essential, but it cannot be described by traditional Fick or Knudsen diffusion models. In this work, we use dual control volume–grand canonical molecular dynamics method to systematically investigate the permeation process of shale gas in montmorillonite (i.e., a clay mineral of shale) at different geological depths. Results indicate that temperature, pressure, and pore size have an important effect on the permeability, and Knudsen equation cannot describe the permeability of shale gas. Accordingly, on the basis of these simulated data, we propose a new mesoscale model to describe the permeability of shale gas at geological depths. The new mesoscale model shows extensive applicability and can excellently reproduce the extrapolation testing data, and it satisfactorily bridges the gap between Knudsen diffusion and Fick diffusion, which provides important fundamentals for exploitation of shale gas. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1059–1066, 2018
Evaluating minimally invasive sample collection methods for telomere length measurement
Authors: Goldman Elisabeth A. , Eick Geeta N. , Compton Devan , Kowal Paul , Snodgrass J. Josh , Eisenberg Dan T.A. , Sterner Kirstin N.
Published: September 2017

Objectives

Telomere length (TL) is a biomarker of aging and age‐related decline. Although venous blood is considered the “gold standard” for TL measurement, its collection is often not feasible or desired in nonclinical settings. Saliva and dried blood spots (DBS) have been used as alternatives when venipuncture cannot be performed. However, it is not known whether these sample types yield TL measurements comparable to those obtained from venous blood. We sought to determine whether different samples from the same individual yield comparable TL measurements.

Methods

We extracted DNA from matched buffy coat, saliva (Oragene and Oasis), and DBS (venous and capillary) samples from 40 women aged 18‐77 years. We used the monochrome multiplex qPCR (MMQPCR) assay to measure TL in all sample types for each participant and applied quality control measures to retain only high‐quality samples for analysis. We then compared TL from buffy coat and saliva to examine how these measurements differ and to test if TL is correlated across sample types.

Results

TL differed significantly across buffy coat, Oragene saliva, and Oasis saliva samples. TL from buffy coat and Oragene saliva was moderately correlated (ρ = 0.48, P = .002) and the most similar in size. Oasis saliva TL was not correlated with buffy coat or Oragene saliva TL, and was the shortest. DBS DNA yields were inadequate for TL measurement using the MMQPCR assay.

Conclusions

Using a matched dataset we demonstrate that sample type significantly influences the TL measurement obtained using the MMQPCR assay.
Prenatal diagnosis of femoral facial syndrome: Three case reports and literature review
Authors: Luisin Marion , Chevreau Julien , Klein Céline , Naepels Philippe , Demeer Bénédicte , Mathieu‐Dramard Michèle , Jedraszak Guillaume , Gondry‐Jouet Catherine , Gondry Jean , Dieux‐Coeslier Anne , Morin Gilles
Published: September 2017

Facial femoral syndrome (FFS) is a rare congenital abnormality, also known as femoral hypoplasia‐unusual facies syndrome, characterized by variable degrees of femoral hypoplasia, associated with specific facial features. Other organ malformations are sometimes present. Most cases are sporadic, but rare family observations suggest genetic origin. However, no chromosomal or genetic abnormalities have ever been incriminated. We conducted a comprehensive literature review and added three new unreported observations. Through these 92 cases, authors aimed to determine sonographic signs that should direct towards diagnosis, and discuss potential genetic etiology. Diagnosis was suspected prenatally in 27.2% of cases, and maternal diabetes was found in 42.4% of patients. When fetal karyotype was available, it was normal in 97.1% of cases, but genomic variations of unknown significance were discovered in all three cases in which array comparative genomic hybridization (CGH) techniques were applied. Femoral affection defining FFS was hypoplasia in 78.3% of cases, agenesis in 12%, and both in 9.8%. Affection was bilateral in 84.8% of cases. Retrognathia was present in 65.2% of cases, cleft lip and/or palate in 63%, and other organ malformations in 53.3%. Intellectual development was normal in 79.2% of cases. Better prenatal recognition of this pathology, notably frequently associated malformations, should lead to a more precise estimation of functional prognosis. It seems likely that today's tendency to systematically employ array‐CGH and exome/genome sequencing methods to investigate malformative sequences will allow the identification of a causal genetic abnormality in the near future.
Total Syntheses of the Isomeric Aglain Natural Products Foveoglin A and Perviridisin B: Selective Excited‐State Intramolecular Proton‐Transfer Photocycloaddition
Authors: Wang Wenyu , Clay Anthony , Krishnan Retheesh , Lajkiewicz Neil J. , Brown Lauren E. , Sivaguru Jayaraman , Porco John A.
Published: September 2017

Selective excited‐state intramolecular proton‐transfer (ESIPT) photocycloaddition of 3‐hydroxyflavones with trans, trans‐1,4‐diphenyl‐1,3‐butadiene is described. Using this methodology, total syntheses of the natural products (±)‐foveoglin A and (±)‐perviridisin B were accomplished. Enantioselective ESIPT photocycloaddition using TADDOLs as chiral hydrogen‐bonding additives provided access to (+)‐foveoglin A. Mechanistic studies have revealed the possibility for a photoinduced electron‐transfer (PET) pathway.
Experimental and Computational Study of an Unexpected Iron‐Catalyzed Carboetherification by Cooperative Metal and Ligand Substrate Interaction and Proton Shuttling
Authors: El‐Sepelgy Osama , Brzozowska Aleksandra , Azofra Luis Miguel , Jang Yoon Kyung , Cavallo Luigi , Rueping Magnus
Published: September 2017

An iron‐catalyzed cycloisomerization of allenols to deoxygenated pyranose glycals has been developed. Combined experimental and computational studies show that the iron complex exhibits a dual catalytic role in that the non‐innocent cyclopentadienone ligand acts as proton shuttle by initial hydrogen abstraction from the alcohol and by facilitating protonation and deprotonation events in the isomerization and demetalation steps. Molecular orbital analysis provides insight into the unexpected and selective formation of the 3,4‐dihydro‐2H‐pyran.
The effect of sodium stearate‐modified hydrocalumite on the thermal stability of poly(vinyl chloride)
Authors: Yang Huan , Yang Zhanhong
Published: September 2017

Hydrocalumite as a new‐type of thermal stabilizer used in poly(vinyl chloride) resin had been well prepared by using precipitation transformation method. The as‐prepared hydrocalumite was then modified by sodium stearate in different condition including temperature, stirring time, and the amount of sodium stearate. Scanning electron microscopy tests demonstrate that hydrocalumite had been well modified. Illustrated by activation grade, the static oven heat aging experiments and the rate of thermal weight loss, it turns out that the best modification condition is when the addition of sodium stearate is 6% of hydrocalumite (wt), the reacting temperature is 90 °C, and the stirring time is 100 min. Static thermal aging test shows that the aging time got improved at least 30 min under the high temperature of 190 °C, and the time when Congo red test paper began to turn blue for modified hydrocalumite is 20 min longer than that of unmodified hydrocalumite. All results turn out to be that the hydrocalumite modified by sodium stearate in such condition had good compatibility with poly(vinyl chloride) and presented better thermal stability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45758.
Preparation of polycarbonate/poly(acrylonitrile‐butadiene‐styrene)/mesoporous silica nanocomposite films and its rheological, mechanical, and sound absorption properties
Authors: Sim Sora , Kwon Oh Min , Ahn Kyung Hyun , Lee Hyeong Rae , Kang Yeon June , Cho Eun‐Bum
Published: September 2017

The homogeneous polycarbonate/poly(acrylonitrile‐butadiene‐styrene) (PC/ABS) nanocomposite thin films were prepared by a facile solvent casting method using phenylene modified‐mesoporous silica materials as additives and dichloromethane as a solvent. The physicochemical analyses using small‐angle X‐ray scattering, nitrogen adsorption–desorption, solid‐state 13C and 29Si nuclear magnetic resonance, and scanning electron microscope were investigated to provide clear physical and chemical properties for modified‐mesoporous materials and nanocomposite films. Tensile tests were performed at room temperature according to ASTM D638. Rheological properties were also analyzed to observe any variance of solid–liquid property. As a compatibilizer and a reinforcing filler, mesoporous (organo‐)silicas showed enhanced features in rheological and mechanical properties. The sound absorption coefficient was measured by the impedance tube up to 6400 Hz according to ISO 10534‐2. It was found that the PC/ABS nanocomposites containing mesoporous materials can be used as a sound‐proofing support material depending on fabrication process. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45777.
Epoxy resins toughened with in situ azide–alkyne polymerized polysulfones
Authors: Ying Wu Bin , Yang Hee Sang , Moon Da Som , Lee Min Woo , Ko Na Yeong , Kwak Nho Hoon , Lee Bumjae , Zhu Jin , Zhang Ruoyu
Published: September 2017

To simultaneously improve the fracture toughness and heat resistance of a cured toughened epoxy resin along with a reduction in its viscosity during the mixing process, two novel polysulfone‐type polymers are synthesized via azide–alkyne polymerization for use as toughening agents. The epoxy resin toughened with these polymers by in situ azide–alkyne polymerization during the cure process, which shows excellent processibility and based on the significantly lower viscosity (61 and 62 cP) during epoxy mixing process than that of commonly commercial polyethersulfone (PES, 127,612 cP). The novel polysulfone‐type polymer toughened epoxy resin showed the advantage in excellent fracture toughness than the PES toughened epoxy. In addition, the glass transition temperature of the novel polysulfone‐type polymer toughened epoxy resin is similar to that of the neat one (∼230 °C) and does not decrease, which implies excellent heat resistance of the toughened epoxy. These phenomena can be attributed to the formation of semi‐interpenetrating polymer networks comprising the epoxy network and the linear polysulfone‐type polymers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45790.
The Role of Ellis‐Van Creveld 2(EVC2) in Mice During Cranial Bone Development
Authors: Kwon Edwin K. , Louie Ke'ale , Kulkarni Anshul , Yatabe Marilia , Ruellas Antonio Carlos de Oliveira , Snider Taylor N. , Mochida Yoshiyuki , Cevidanes Lucia H. S. , Mishina Yuji , Zhang Honghao
Published: September 2017

EvC syndrome is a type of autosomal‐recessive chondrodysplasia. Previous case studies in patients suggest abnormal craniofacial development, in addition to dwarfism and tooth abnormalities. To investigate how craniofacial development is affected in EvC patients, surface models were generated from micro‐CT scans of control mice, Evc2 global mutant mice and Evc2 neural crest‐specific mutant mice. The anatomic landmarks were placed on the surface model to assess the morphological abnormalities in the Evc2 mutants. Through analyzing the linear and angular measurements between landmarks, we identified a smaller overall skull, shorter nasal bone, shorter frontal bone, and shorter cranial base in the Evc2 global mutants. By comparing neural crest‐specific Evc2 mutants with control mice, we demonstrated that the abnormalities within the mid‐facial regions are not accounted for by the Evc2 mutation within these regions. Additionally, we also identified disproportionate length to width ratios in the Evc2 mutants at all levels from anterior to posterior of the skull. Overall, this study demonstrates a more comprehensive analysis on the craniofacial morphological abnormalities in EvC syndrome and provides the developmental insight to appreciate the impact of Evc2 mutation within the neural crest cells on multiple aspects of skull deformities. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:46–55, 2018. © 2017 Wiley Periodicals, Inc.
Phase III Randomized Study of SB5, an Adalimumab Biosimilar, Versus Reference Adalimumab in Patients With Moderate‐to‐Severe Rheumatoid Arthritis
Authors: Weinblatt Michael E. , Baranauskaite Asta , Niebrzydowski Jaroslaw , Dokoupilova Eva , Zielinska Agnieszka , Jaworski Janusz , Racewicz Artur , Pileckyte Margarita , Jedrychowicz‐Rosiak Krystyna , Cheong Soo Yeon , Ghil Jeehoon
Published: September 2017

Objective

SB5 is a biosimilar agent for adalimumab (ADA). The aim of this study was to evaluate the efficacy, pharmacokinetics (PK), safety, and immunogenicity of SB5 in comparison with reference ADA in patients with rheumatoid arthritis (RA).

Methods

In this phase III, randomized, double‐blind, parallel‐group study, patients with moderately to severely active RA despite treatment with methotrexate were randomized 1:1 to receive SB5 or reference ADA at a dosage of 40 mg subcutaneously every other week. The primary efficacy end point was the response rate based on the American College of Rheumatology 20% improvement criteria (ACR20) at week 24 in the per‐protocol set (completer analysis). Additional end points included efficacy, PK, safety, and immunogenicity assessments.

Results

Of the 544 patients randomized to receive a study drug, the full analysis set comprised 542 patients (269 in the SB5 group, 273 in the reference ADA group) and the per‐protocol set comprised 476 patients (239 receiving SB5, 237 receiving reference ADA). The ACR20 response rate at week 24 in the per‐protocol set was equivalent between those receiving SB5 and those receiving reference ADA (72.4% and 72.2%, respectively); the difference in the ACR20 response rate (0.1%, [95% confidence interval −7.83%, 8.13%]) was within the predefined equivalence margin (±15%). Similar results were seen in the full analysis set (missing data being considered a nonresponse). The SB5 and reference ADA treatment groups were comparable across other end points, including the ACR 50% and ACR 70% improvement response rates, Disease Activity Score in 28 joints based on the erythrocyte sedimentation rate, PK data, incidence of treatment‐emergent adverse events, and the antidrug antibody response. Subgroup analyses showed that the efficacy and safety of SB5 and reference ADA were comparable regardless of antidrug antibody status.

Conclusion

The ACR20 response rate at week 24 was equivalent between patients treated with the biosimilar agent SB5 and those treated with reference ADA. SB5 and reference ADA were both well tolerated, with comparable safety profiles, in patients with RA.
Copper‐Catalyzed Alkynylboration of Alkenes with Diboron Reagents and Bromoalkynes
Authors: Gong Tian‐Jun , Yu Shang‐Hai , Li Kuan , Su Wei , Lu Xi , Xiao Bin , Fu Yao
Published: September 2017

An efficient method for the synthesis of homopropargylboronates by copper‐catalyzed alkynylboration of alkenes with diboron reagents and bromoalkynes has been developed. The alkynylboration reaction features high selectivity and efficiency, mild reaction conditions, wide substrate scope, and functional‐group compatibility, and is a highly attractive complement to existing methods for the synthesis of homopropargylboronates. Both the boryl and alkynyl groups are good potential functional groups for the subsequent manipulations that provide access to a variety of important molecule structures.
Solvent‐Driven Iodine‐Mediated Oxidative Strategies for the Synthesis of Bis(imidazo[1,2‐a]pyridin‐3‐yl)sulfanes and Disulfanes
Authors: Shakoor S. M. Abdul , Agarwal Devesh S. , Khullar Sadhika , Mandal Sanjay K. , Sakhuja Rajeev
Published: September 2017

Two efficient iodine‐mediated strategies, which are economical and one‐pot, are described to access bis(imidazo[1,2‐a]pyridin‐3‐yl)sulfanes and bis(imidazo[1,2‐a]pyridin‐3‐yl)disulfanes in chloroform and acetic acid, respectively, by a direct oxidative homocoupling of imidazo‐heterocycles using inexpensive sodium sulfide as a sulfur source. These strategies are scalable, and an array of substrates delivered their corresponding stable sulfur‐bridged imidazo‐heterocycles in excellent yields.
Dynamic Mg2B8 Cluster: A Nanoscale Compass
Authors: Wang Ying‐Jin , Feng Lin‐Yan , Guo Jin‐Chang , Zhai Hua‐Jin
Published: September 2017

Boron‐based binary cluster Mg2B8 is shown to adopt a compass‐like structure via computational global searches, featuring an Mg2 dimer as the needle and a disk‐shaped B8 molecular wheel as baseplate. The nanocompass has a diameter of 0.35 nm. Born–Oppenheimer molecular dynamics simulations indicate that Mg2B8 is structurally fluxional with the needle rotating freely on the baseplate, analogous to a functioning compass. The dynamics is readily initiated via a ultrasoft vibrational mode. The rotational barrier is only 0.1 kcal mol−1 at the single‐point CCSD(T) level. Chemical bonding analysis suggests that the cluster compass can be formulated as [Mg2]2+[B8]2−; that is, the baseplate and the needle are held together primarily through ionic interactions. The baseplate is doubly aromatic with π and σ sextets. The bonding pattern provides a dilute, continuous, and delocalized electron cloud, which underlies the dynamics of the nanocompass.
Preparation of Alkylated and Perfluorinated ZnPc‐modified Carbon Nanotubes and their Application as Conductive Fillers for Poly(vinylidene fluoride) Composite Dielectrics
Authors: Hong Sun‐Mi , Mutyala Anil Kumar , Cha Myung Joo , Seo Jung Hwa , Kang Young‐Ah , Park Jong S.
Published: September 2017

This study includes the synthesis and application of unsymmetrical zinc phthalocyanines (ZnPcs) 1 and 2 with three tertiary‐butylated (tBu) and hexyl‐tridecafluoro (C6F13) groups that are further connected with carbon nanotubes (CNTs) through an amide bonding to yield Pc‐functionalized CNTs 3 and 4, respectively. The properties of the resulting Pc‐CNT complexes are thoroughly investigated using various analytical techniques, revealing that 3 and 4 enhanced the dispersion and adhesion properties of the CNTs to poly(vinylidene fluoride) (PVDF) matrix, and thereby improved the electrical and dielectric properties. Particularly, the presence of long and fluorinated substituents in 4 allowed for better interfacial compatibility compared to alkylated Pc‐CNT 3, leading to more stable dielectric behaviors. Our work has demonstrated that perfluorinated and alkylated Pc‐CNT complex could be facile and effective approach toward high‐performance polymer‐based dielectrics.
Decremental responses in patients with motor neuron disease
Authors: Alanazy Mohammed H. , Hegedus Janka , White Chris , Korngut Lawrence
Published: September 2017

Objective

Involvement of the neuromuscular junction (NMJ) in amyotrophic lateral sclerosis (ALS) has been reported and is increasingly recognized as an important pathophysiological aspect. The relationship between decrement and clinical measures for possible application as a biomarker has not been comprehensively explored.

Methods

We performed routine repetitive nerve stimulation (RNS) of three nerves on patients with ALS. We captured measures of muscle strength, grip strength, fatigability, and calculated slow vital capacity (SVC) rates of change assessing for associations.

Results

In 42 subjects, 210 muscles were studied. Negative correlation was found between the percentage of decrement and compound muscle action potential (CMAP) amplitude. Approximately half of the patients with hand weakness did not have decrement. There was no significant correlation between decrement and handgrip fatigue, SVC < 80% predicted, or more rapid worsening of SVC over time.

Conclusions

Abnormal decremental responses are well described in ALS. We report that the degree of decremental response does not correlate with the degree of weakness. Abnormal decrement is only rarely present in nerve–muscle pairs with normal motor power. Our findings did not support a correlation between abnormal decrement and clinical measures suggesting that RNS may not be useful as a biomarker to monitor ALS progression.
Mycoplasma pneumoniae‐associated encephalitis complicated by cerebral salt wasting syndrome
Authors: Lin Ya‐Lan , Hung Kun‐Long , Lo Chiao‐Wei
Published: September 2017

Key Clinical Message

Cerebral salt wasting syndrome can occur in children with encephalitis. Clinicians should be aware of hyponatremia in patients who develop polyuria with the signs of dehydration and deteriorated consciousness. Furthermore, patients who present with status epilepticus or who are suspected to have high intracranial pressure may have an increased risk of cerebral salt wasting syndrome.
Direct Access to N‐Unprotected α‐ and/or β‐Tetrasubstituted Amino Acid Esters via Direct Catalytic Mannich‐Type Reactions Using N‐Unprotected Trifluoromethyl Ketimines
Authors: Sawa Masanao , Morisaki Kazuhiro , Kondo Yuta , Morimoto Hiroyuki , Ohshima Takashi
Published: September 2017

Direct catalytic C−C bond‐forming addition to N‐unprotected ketimines is an efficient and straightforward method of synthesizing N‐unprotected tetrasubstituted amines that eliminates prior protection/deprotection steps and allows facile transformation of the products. Despite its advantages, however, N‐unprotected ketimines have difficulties in C−C bond‐forming reactions, and only a limited number of reactions and substrates are reported compared with their N‐protected counterparts. Herein we report that N‐unprotected trifluoromethyl ketimines are effective for C−C bond‐forming reactions using Mannich‐type reactions as a model case. We demonstrate that Lewis acid catalysis was effective for promoting reactions with various N‐unprotected trifluoromethyl ketimines, and thiourea organocatalysis was effective for promoting highly enantioselective reactions with various carbonyl nucleophiles, providing direct access to various N‐unprotected α‐ and/or β‐tetrasubstituted amino acid esters. Furthermore, direct construction of vicinal tetrasubstituted chiral carbon stereocenters was achieved for the first time in a highly enantio‐ and diastereoselective manner. These results demonstrate the potential of N‐unprotected ketimines as substrates applicable to many other addition reactions.
Environmental Gas Sensing with Cavitands
Authors: Pinalli Roberta , Pedrini Alessandro , Dalcanale Enrico
Published: September 2017

Environmental gas sensing needs stringent sensor requirements in terms of sensitivity, selectivity and ruggedness. One of the major issues to be addressed is combining in a single device the conflicting requirements of molecular‐level selectivity and low‐ppb sensitivity. The exploitation of synthetic molecular receptors as sensing materials is particularly attractive to address the selectivity issue, to single out the desired analytes in the presence of overwhelming amounts of interferents. This minireview summarizes the strategies in environmental gas and vapor sensing using molecular receptors as selective hosts for specific analytes, with the main focus on cavitands. In particular, we highlight the use of these macrocycles as selective preconcentrator units to be integrated into portable devices for environmental monitoring. Depending on the class of analytes to be detected, the molecular recognition properties of cavitands can be manipulated through the proper choice of the bridging groups at the upper rim, and their transducer integration can be implemented through the manifold functionalization options at the lower rim.
Magnetic γ′‐Fe4N/Fe3C, χ‐Fe5C2, and θ‐Fe3C by a Simple Route for Application as Electrochemical Catalysts
Authors: Lei Xiang , Ye Zhantong , Zhao Nan , Lei Feifei , Yang Hua
Published: September 2017

A new and simple method to fabricate magnetic Fe4N/Fe3C samples is reported. Meanwhile, pure phase iron carbides (θ‐Fe3C and χ‐Fe5C2) were obtained by controlling experimental conditions. The structures, magnetic properties, and morphology of the samples were investigated according to the generalized analysis of X‐ray diffraction, X‐ray photoelectron spectroscopy, as well as transmission electron microscopy and vibrating sample magnetometry. The magnetic properties measurement revealed the remarkable magnetic properties of the samples at 2 and 300 K. The application of the prepared samples as catalysts for oxygen evolution reaction was also investigated in alkaline solution. This simple and convenient route provides a new path to fabricate other metal nitrides and carbides.