bluuebunny/crossref_metadata_2025 huggingface dataset:
A stable auroral red (SAR) arc with multiple emission features
Authors: Mendillo Michael , Finan Robert , Baumgardner Jeffrey , Wroten Joei , Martinis Carlos , Casillas Marcus
Published: October 2016

Stable auroral red (SAR) arcs offer subvisible evidence for storm time linkages between the inner magnetosphere and the midlatitude ionosphere. A SAR arc's defining characteristics are horizon‐to‐horizon east‐west extent, a few degrees of latitude in meridional extent, emission only at the oxygen 6300 Å line, and minimal brightness changes during a night—effects readily provided by steady heat conduction from the ring current‐plasmapause interaction region. Here we describe a typical SAR arc (brightness ~300 rayleighs) with several superimposed patches of emission in two oxygen lines (with a 6300 Å/5577 Å ratio of ~40). We find no evidence for highly localized heating effects but rather evidence from GPS satellites supporting low‐energy electron precipitation as the SAR arc modulating mechanism. Seven brightness peaks with average longitude spacing of ~4° define a new spatial pattern for SAR arc studies.
Load relaxation of olivine single crystals
Authors: Cooper Reid F. , Stone Donald S. , Plookphol Thawatchai
Published: October 2016

Single crystals of ferromagnesian olivine (San Carlos, AZ, peridot; ~Fo88‐90) have been deformed in both uniaxial creep and load relaxation under conditions of ambient pressure, T = 1500°C and
 = 10−10 atm; creep stresses were in the range 40 ≤ σ1 (MPa) ≤ 220. The crystals were oriented such that the applied stress was parallel to [011]c, which promotes single slip on the slowest slip system in olivine, (010)[001]. The creep rates at steady state match well the results of earlier investigators, as does the stress sensitivity (a power law exponent of n = 3.6). Dislocation microstructures, including spatial distribution of low‐angle (subgrain) boundaries, additionally confirm previous investigations. Inverted primary creep (an accelerating strain rate with an increase in stress) was observed. Load relaxation, however, produced a singular response—a single hardness curve—regardless of the magnitude of creep stress or total accumulated strain preceding relaxation. The log stress versus log strain rate data from load‐relaxation and creep experiments overlap to within experimental error. The load‐relaxation behavior is distinctly different than that described for other crystalline solids, where the flow stress is affected strongly by work hardening such that a family of distinct hardness curves is generated, which are related by a scaling function. The response of olivine for the conditions studied, we argue, indicates flow that is rate limited by dislocation glide, reflecting specifically a high intrinsic lattice resistance (Peierls stress).
Global observations of cloud‐sensitive aerosol loadings in low‐level marine clouds
Authors: Andersen H. , Cermak J. , Fuchs J. , Schwarz K.
Published: October 2016

Aerosol‐cloud interaction is a key component of the Earth's radiative budget and hydrological cycle, but many facets of its mechanisms are not yet fully understood. In this study, global satellite‐derived aerosol and cloud products are used to identify at what aerosol loading cloud droplet size shows the greatest sensitivity to changes in aerosol loading (ACSmax). While, on average, cloud droplet size is most sensitive at relatively low aerosol loadings, distinct spatial and temporal patterns exist. Possible determinants for these are identified with reanalysis data. The magnitude of ACSmax is found to be constrained by the total columnar water vapor. Seasonal patterns of water vapor are reflected in the seasonal patterns of ACSmax. Also, situations with enhanced turbulent mixing are connected to higher ACSmax, possibly due to intensified aerosol activation. Of the analyzed aerosol species, dust seems to impact ACSmax the most, as dust particles increase the retrieved aerosol loading without substantially increasing the concentration of cloud condensation nuclei.
A test for Io's magma ocean: Modeling tidal dissipation with a partially molten mantle
Authors: Bierson C. J. , Nimmo F.
Published: October 2016

Magnetic induction measurements and astrometry provide constraints on the internal structure of Io, a volcanically active moon of Jupiter. We model the tidal response of a partially molten Io using an Andrade rheology which is supported by silicate deformation experiments. This model uses material properties similar to the Earth's mantle and includes feedbacks between partial melting, tidal heat production, and melt transport. We are able to satisfy constraints provided by the measured imaginary part of the tidal Love number Im(k2), the inferred depth and melt fraction of a near‐surface partially molten layer, and the observed equatorial concentration of volcanic landforms. We predict a value for the real part of the tidal Love number of Re(k2) = 0.09 ± 0.02, much smaller than the value of Re(k2)≈0.5 predicted for an Io with a fluid magma ocean. Future spacecraft observations should be able to measure this value and test which model is correct.
CGILS Phase 2 LES intercomparison of response of subtropical marine low cloud regimes to CO2 quadrupling and a CMIP3 composite forcing change
Authors: Blossey Peter N. , Bretherton Christopher S. , Cheng Anning , Endo Satoshi , Heus Thijs , Lock Adrian P. , van der Dussen Johan J.
Published: October 2016

Phase 1 of the CGILS large‐eddy simulation (LES) intercomparison is extended to understand if subtropical marine boundary‐layer clouds respond to idealized climate perturbations consistently in six LES models. Here the responses to quadrupled carbon dioxide (“fast adjustment”) and to a composite climate perturbation representative of CMIP3 multimodel mean 2×CO2 near‐equilibrium conditions are analyzed. As in Phase 1, the LES is run to equilibrium using specified steady summertime forcings representative of three locations in the Northeast Pacific Ocean in shallow well‐mixed stratocumulus, decoupled stratocumulus, and shallow cumulus cloud regimes. The results are generally consistent with a single‐LES study of Bretherton et al. () on which this intercomparison was based. Both quadrupled CO2 and the composite climate perturbation result in less cloud and a shallower boundary layer for all models in well‐mixed stratocumulus and for all but a single LES in decoupled stratocumulus and shallow cumulus, corroborating similar findings from global climate models (GCMs). For both perturbations, the amount of cloud reduction varies across the models, but there is less intermodel scatter than in GCMs. The cloud radiative effect changes are much larger in the stratocumulus‐capped regimes than in the shallow cumulus regime, for which precipitation buffering may damp the cloud response. In the decoupled stratocumulus and cumulus regimes, both the CO2 increase and CMIP3 perturbations reduce boundary‐layer decoupling, due to the shallowing of inversion height.
Frequency and Duration of Adrenal Suppression Following Glucocorticoid Therapy in Children With Rheumatic Diseases
Authors: Ahmet Alexandra , Brienza Vincent , Tran Audrey , Lemieux Julie , Aglipay Mary , Barrowman Nick , Duffy Ciaran , Roth Johannes , Jurencak Roman
Published: October 2016

Objective

Adrenal suppression (AS), a glucocorticoid (GC) side effect with potentially significant morbidity, is poorly understood. The purpose of our study was to determine frequency, duration, and predictors of AS following a gradual taper of GC in children with rheumatic conditions.

Methods

A prospective, observational cohort study was conducted. All patients ages ≤16 years ready to discontinue GC after >4 weeks of therapy were included. Morning cortisol was tested 4 weeks after GC taper to physiologic doses and then repeatedly until normalization. GCs were subsequently discontinued and a low‐dose adrenocorticotropic hormone stimulation test was performed.

Results

The study was completed by 31 of 39 patients. The median age was 12.9 years and median duration of GC therapy was 39.6 weeks. Seventeen patients (54.8%) had AS. Of the patients with AS, 50% showed recovery by 7 months. Two patients had persistent AS at 12 months and 1 patient at 2 years. A higher maximum GC dose was a significant predictor for the development of AS.

Conclusion

More than 50% of our patients had AS after GC discontinuation, despite a gradual taper of GC. Stress steroids should be considered in children treated with long‐term GC, even after steroid discontinuation, to prevent possible adrenal crisis.
Recent Development of Transparent Conducting Oxide‐Free Flexible Thin‐Film Solar Cells
Authors: Guo Wenxi , Xu Zijie , Zhang Fayin , Xie Shuyao , Xu Hongyao , Liu Xiang Yang
Published: October 2016

The rapid development of the modern electronics gives rise to higher demands of flexible and wearable energy resources. Flexible transparent conducting electrodes (TCEs) are one of the essential components for flexible/wearable thin‐film solar cells (SCs). In this regard, commercial indium tin oxide (ITO) on plastics has demonstrated superior optoelectronic performance although some drawbacks, i.e., the low abundance, film brittleness, low infrared transmittance, and poor chemical stability remain. On the other hand, several other transparent conducting oxide (TCO)‐free transparent conductive materials, such as carbon nanotubes (CNTs), graphene, metallic nanowires (NWs), and conducting polymers, have experienced a rapid development to address these issues. In this feature article, an overview over the latest development of several flexible TCO‐free thin film SCs, i.e., organic solar cells (OSCs), dye‐sensitized solar cells (DSSCs), perovskite solar cells (pero‐SCs), and fiber/wire‐shaped SCs is provided. Three groups of flexible TCO‐free thin film solar cells can be categorized according to their configurations: (i) front‐side illuminated planar configuration; (ii) back‐side illuminated planar configuration, and (iii) fiber‐shaped solar cells (FSSCs). The article is focused on flexible TCO‐free TCEs, including CNTs, graphene, metallic NW/nanotroughs, metallic grids, conducting polymers, metallic fiber, and carbon based fibers.
Nanostructuring Ferroelectrics via Focused Ion Beam Methodologies
Authors: Burns Stuart R. , Gregg J. Marty , Nagarajan Valanoor
Published: October 2016

As we reach the physical limit of Moore's law and silicon based electronics, alternative schemes for memory and sensor devices are being proposed on a regular basis. The properties of ferroelectric materials on the nanoscale are key to developing device applications of this intriguing material class, and nanostructuring has been readily pursued in recent times. Focused ion beam (FIB) microscopy is one of the most significant techniques for achieving this. When applied in tandem with the imaging and nanoscale manipulation afforded by proximal scanning force microscopy tools, FIB‐driven nanoscale characterization has demonstrated the power and ability which simply may not be possible by other fabrication techniques in the search for innovative and novel ferroic phenomena. At the same time the process is not without pitfalls; it is time‐consuming and success is not always guaranteed thus often being the bane in progress. This balanced review explores a brief history of the relationship between the FIB and ferroelectrics, the fascinating properties it has unveiled, the challenges associated with FIB that have led to alternative nanostructuring techniques and finally new ideas that should be explored using this exciting technique.
Radial Growth in 2D Revisited: The Effect of Finite Density, Binding Affinity, Reaction Rates, and Diffusion
Authors: Bihr Timo , Sadafi Fabrizio‐Zagros , Seifert Udo , Taylor Robin Klupp , Smith Ana‐Sunčana
Published: October 2016

Dendrite growth of metal patches on colloidal particles shows a variety of structures depending on the preparation conditions. The morphology of these patches suggests a cross‐over from a reaction to a diffusion limited growth, implicating diffusion on the particle surface. Interestingly, the morphological and optical characteristics of the patches continuously change between two limiting behaviors. To understand this growth process, extensive simulations are performed, studying the fractal dimension and the dynamics of growth of a patch on a particle of a finite size, as a function of the initial density and the binding affinity of diffusing tracers. Several important growth regimes are characterized that enable to optimize the pathway for the synthesis of optically active, patchy particles.
Highly Exfoliated Reduced Graphite Oxide Powders as Efficient Lubricant Oil Additives
Authors: Li Yingru , Zhao Jun , Tang Cheng , He Yongyong , Wang Yongfu , Chen Ji , Mao Junyuan , Zhou Qinqin , Wang Baoyuan , Wei Fei , Luo Jianbin , Shi Gaoquan
Published: October 2016

Highly exfoliated reduced graphite oxide (heRGO) is prepared by thermal reduction of crude graphite oxide (GO) powders with the assistance of KOH. By using the mixtures of KOH and GO with different weight ratios (n) as the starting materials, the resulting heRGO‐n powders show different microstructures and lubrication properties. The optimized heRGO‐4 powders have an average particle size around 1 μm, a “loose book”‐like layered microstructure, and a large specific surface area of 829.5 m2 g−1. The unique microstructure and tiny particle sizes have made this graphene material to be an extraordinary high‐performance additive of poly(α‐olefin) lubricant oil (type 6, PAO‐6). By adding 0.5% (by weight, wt%) heRGO‐4, the coefficient of friction of PAO‐6 is decreased by 44% and the wear scar depth is reduced by more than 90%. The lubrication effect of heRGO‐4 is much superior to that of thermally reduced graphite oxide. Given its facile, cheap, and scalable preparation process, heRGO‐4 has a great potential for industrial applications.
Nonvolatile All‐Optical 1 × 2 Switch for Chipscale Photonic Networks
Authors: Stegmaier Matthias , Ríos Carlos , Bhaskaran Harish , Wright C. David , Pernice Wolfram H. P.
Published: October 2016

Integrated chip‐level photonics has the potential to revolutionize future computer systems by eliminating the “von‐Neumann information bottleneck” and the power losses resulting from the use of electrical interconnects. Yet, the need for optical‐to‐electrical conversion has so far hindered the implementation of chip‐level all‐optical routing schemes, which remain operational without continuous power consumption. Here, a crucial component to successful implementation of such all‐photonic networks is demonstrated – an effective, practicable all‐optical nonvolatile switch. Current integrated all‐optical switches require constant bias power to operate, and lose their state when it is removed. By contrast, our switch is entirely nonvolatile, with the direction of light flow altered by switching the phase state of an embedded phase‐change cell using 1 ps optical pulses. High on/off switching contrast devices are achieved that are fully integrated and compatible with existing photonic circuits. It is shown that individual switching events occur with transition times below 200 ps and thus hold promise for ultrafast light routing on chip. The approach offers a reliable and simple route toward hybrid reconfigurable photonic devices without the need for electrical contacting.
In Vivo Luminescence Nanothermometry: from Materials to Applications
Authors: del Rosal Blanca , Ximendes Erving , Rocha Ueslen , Jaque Daniel
Published: October 2016

The current status of the use of luminescent nanoparticles for thermometry in animal models is reviewed in detail. The different types of luminescent nanoparticles capable of deep tissue temperature sensing are described, paying special attention to the physical mechanisms at the root of their thermal sensing capacity. Their thermal sensitivities are listed and compared. This review describes the most relevant experiments, in which luminescence nanothermometry has been successfully applied at the small animal level, including the development of controlled thermal therapies as well as subtissue diagnosis procedures. Advantages and disadvantages of different luminescent nanothermometers are discussed.
Modified PEDOT Layer Makes a 1.52 V Voc for Perovskite/PCBM Solar Cells
Authors: Zuo Chuantian , Ding Liming
Published: October 2016

The work functions for charge transport layers in perovskite solar cells affect device performance significantly. In this work, the regular poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is modified by adding a polymer electrolyte PSS‐Na to improve its HTL function in perovskite solar cells. The modified PEDOT:PSS films (called m‐PEDOT:PSS) possess higher work function than the regular one. Its energy level matches the valence band of perovskite very well, leading to enhanced Voc and PCE (power conversion efficiency). When CH3NH3PbI3 is used as the light absorber, the cell with PEDOT:PSS HTL gives a Voc of 0.96 V and a PCE of 12.35%, while the cell with m‐PEDOT:PSS layer gives a Voc of 1.11 V and a PCE of 15.56%. Enhanced Voc and PCE are also achieved when CH3NH3PbI2Br or CH3NH3PbBr3 is used as the light absorber. The m‐PEDOT:PSS/CH3NH3PbBr3/PC61BM solar cells demonstrate an outstanding Voc of 1.52 V.
Wearable High‐Performance Supercapacitors Based on Silver‐Sputtered Textiles with FeCo2S4–NiCo2S4 Composite Nanotube‐Built Multitripod Architectures as Advanced Flexible Electrodes
Authors: Zhu Jian , Tang Shaochun , Wu Juan , Shi Xiling , Zhu Baogang , Meng Xiangkang
Published: October 2016

To achieve high‐performance wearable supercapacitors (SCs), a new class of flexible electrodes with favorable architectures allowing large porosity, high conductivity, and good mechanical stability is strongly needed. Here, this study reports the rational design and fabrication of a novel flexible electrode with nanotube‐built multitripod architectures of ternary metal sulfides' composites (FeCo2S4–NiCo2S4) on a silver‐sputtered textile cloth. Silver sputtering is applicable to almost all kinds of textiles, and S2− concentration is optimized during sulfidation process to achieve such architectures and also a complete sulfidation assuring high conductivity. New insights into concentration‐dependent sulfidation mechanism are proposed. The additive‐free FeCo2S4–NiCo2S4 electrode shows a high specific capacitance of 1519 F g−1 at 5 mA cm−2 and superior rate capability (85.1% capacitance retention at 40 mA cm−2). All‐solid‐state SCs employing these advanced electrodes deliver high energy density of 46 W h kg−1 at 1070 W kg−1 as well as achieve remarkable cycling stability retaining 92% of initial capacitance after 3000 cycles at 10 mA cm−2, and outstanding reliability with no capacitance degradation under large twisting. These are attributed to the components' synergy assuring rich redox reactions, high conductivity as well as highly porous but robust architectures. An almost linear increase in capacitance with devices' area indicates possibility to meet various energy output requirements. This work provides a general, low‐cost route to wearable power sources.
Metal‐Organic Framework Cathodes Based on a Vanadium Hexacyanoferrate Prussian Blue Analogue for High‐Performance Aqueous Rechargeable Batteries
Authors: Lee Ji‐Hoon , Ali Ghulam , Kim Dong Hyun , Chung Kyung Yoon
Published: October 2016

Despite the unique advantages of the metal‐organic framework of Prussian blue analogues (PBAs), including a favorable crystallographic structure and facile diffusion kinetics, the capacity of PBAs delivered in aqueous systems has been limited to ≈60 mA h g−1 because only single species of transition metal ions incorporated into the PBAs are electrochemically activated. Herein, vanadium hexacyanoferrate (V/Fe PBA) is proposed as a breakthrough to this limitation, and its electrochemical performance as a cathode for aqueous rechargeable batteries (ARBs) is investigated for the first time. V/Fe PBAs are synthesized by a simple co‐precipitation method with optimization of the acidity and molar ratios of precursor solutions. The V/Fe PBAs provide an improved capacity of 91 mA h−1 under a current density of 110 mA g−1 (C‐rate of ≈1.2 C), taking advantage of the multiple‐electron redox reactions of V and Fe ions. Under an extremely fast charge/discharge rate of 3520 mA g−1, the V/Fe PBA exhibits a sufficiently high discharge capacity of 54 mA h g−1 due to its opened structure and 3D hydrogen bonding networks. V/Fe PBA‐based ARBs are the most promising candidates for large‐scale stationary energy storage systems due to their high electrochemical performance, reasonable cost, and high efficiency.
Effect of Processing Additives on Organic Photovoltaics: Recent Progress and Future Prospects
Authors: Kwon Sooncheol , Kang Hongkyu , Lee Jong‐Hoon , Lee Jinho , Hong Soonil , Kim Heejoo , Lee Kwanghee
Published: October 2016

Due to the short diffusion length of approximately 10 nm of an exciton in bulk heterojunction (BHJ) organic solar cells (OSCs) comprising electron donors and acceptors, a formation with well phase‐separated nanomorphology in BHJ films has been one of the most important issues in achieving efficient charge separation and extraction in OSCs. By adding a small amount of a high boiling point solvent or molecules to a bulk heterojunction (BHJ) solution, processing additive techniques have recently begun to offer an attractive and efficient method for controlling the nanoscale BHJ morphology of state‐of‐the‐art OSCs with power conversion efficiencies (PCEs) exceeding approximately 11%. However, it remains unknown whether the effect of processing additives can potentially pave the way for the ongoing development of various BHJ components and the commercialization of OSCs. Here, recent progress in understanding and developing the effects of processing additives on OSCs is highlighted. This overview suggests possible guidelines for a wide range of BHJ components with respect to morphological/structural evolution. Furthermore, the rational correlations among processing additives, BHJ components, and fabrication technologies and the performance of high‐performance and low‐cost OSCs are discussed along with future commercialization prospects.
Determination of mass transfer resistances of fast reactions in three‐phase mechanically agitated slurry reactors
Authors: Stamatiou Ilias K. , Muller Frans L.
Published: October 2016

A methodology for the determination of mass transfer resistances of fast reactions in three‐phase mechanically agitated slurry reactors under the reaction conditions is presented. The mass transfer resistances affect significantly the overall mass transfer rate, the design equation and consequently the scale up of the reactor. There is not established methodology to separate the mass transfer resistances under reaction conditions by changing catalyst loading and manipulating the process variables, pressure and agitation speed. This allows to avoid the use of different catalyst particles and give the chance to calculate the mass transfer resistances without caring about the type of catalyst. We calculate each mass transfer resistance under conditions which do not allow to neglect any of the resistances. It is shown that the level off of mass transfer rate which is developed in the plot of mass transfer rate against agitation speed plots is not enough to determine the limiting regime. The hydrogenation of styrene over Pd/C (5% catalyst content) is used as case study to demonstrate the methodology. © 2016 American Institute of Chemical Engineers AIChE J, 63: 273–282, 2017
Treatment modalities in sinonasal undifferentiated carcinoma: an analysis from the national cancer database
Authors: Khan Mohemmed N. , Konuthula Neeraja , Parasher Arjun , Genden Eric M. , Miles Brett A. , Govindaraj Satish , Iloreta Alfred M.
Published: October 2016

Background

Sinonasal undifferentiated carcinoma (SNUC) is a rare, aggressive malignancy of unknown etiology with a poor overall prognosis. Its relative rarity has made it difficult to determine the impact of different treatment modalities on survival.

Methods

Retrospective study of cases in the National Cancer Data Base (NCDB). NCDB cases that were diagnosed as having SNUC between January 1, 2004, and December 31, 2013 were included in the analysis. Outcomes of patients treated with surgery followed adjuvant chemoradiotherapy were compared with definitive chemoradiotherapy.

Results

 A 5‐year survival rate of 42.2% was observed in the 460 patients in the analysis. American Joint Committee on Cancer (AJCC) clinical staging data were available for 304 patients. Of these patients, 60.2% had advanced tumors (AJCC stage 3 or 4). Surgery followed by adjuvant chemoradiotherapy was associated with better survival than definitive chemoradiotherapy (55.8% vs 42.6%, p = 0.007) in the study population. However, in late‐stage tumors, there was no difference in survival between the 2 treatment groups (p = 0.22). For late‐stage tumors, the time to initiation of adjuvant therapy was 49.2 ± 5.1 days for the surgery plus adjuvant therapy group as compared with 25.9 ± 2.6 days in the definitive chemoradiotherapy group (p < 0.0001), yet this did not appear to affect outcomes. No differences in age, gender, race, Charlson‐Deyo score, facility type (academic vs nonacademic), or radiation dose were found between the 2 treatment groups (p > 0.05). Margin status played a critical role in the success of surgical resection, as no patients with positive margin status receiving adjuvant therapy survived to 5 years.

Conclusion

Surgery may play a role in a multimodality approach to treatment of late‐stage SNUC if the tumor is amenable to surgical resection and negative margins can be reliably obtained. However, in cases where there may be difficulty obtaining negative margins, or this is considered unlikely preoperatively, surgical resection does not appear to provide any additional survival benefit.
ADR Brief
Authors: Bleemer Russ
Published: October 2016

The Consumer Financial Protection Bureau is sifting through thousands of comments on its long‐running efforts to bar financial services companies from forbidding class processes in consumer contracts that require individual arbitration.
Die Erschließung von Wirkstoffmetaboliten durch übergangsmetallkatalysierte C‐H‐Oxidation: die Leber als Inspiration für die Synthese
Authors: Genovino Julien , Sames Dalibor , Hamann Lawrence G. , Touré B. Barry
Published: October 2016

Können klassische und moderne C‐H‐Oxidationsreaktionen Biotransformationen bei der Synthese von Wirkstoffmetaboliten ergänzen? Wir haben versucht, bei einer Durchsicht der Literatur eine Antwort auf diese wichtige Frage für die Praxis der pharmazeutischen Industrie zu finden. Solche Metaboliten werden während aller Phasen der Wirkstoffsuche und ‐entwicklung benötigt; ihre Synthese ist jedoch noch immer ein ungelöstes Problem. Dieser Aufsatz stellt relevante Anwendungen von chemischen C‐H‐Oxidationen, Elektrochemie und Mikrofluidiktechniken auf Wirkstoff‐Grundgerüste vor, mit denen Metaboliten zugänglich gemacht werden sollen, und fasst vielversprechende Reaktionen für diesen Zweck zusammen. Wo es möglich oder passend ist, wird der Vergleich zur Biotransformation gezogen. So haben wir versucht, bestehende Lücken zu finden, um weitere Aktivitäten auf diesem wichtigen Forschungsfeld anzuspornen.
Synthesis of Highly Selective Submicromolar Microcystin‐Based Inhibitors of Protein Phosphatase (PP)2A over PP1
Authors: Fontanillo Miriam , Zemskov Ivan , Häfner Maximilian , Uhrig Ulrike , Salvi Francesca , Simon Bernd , Wittmann Valentin , Köhn Maja
Published: October 2016

Research and therapeutic targeting of the phosphoserine/threonine phosphatases PP1 and PP2A is hindered by the lack of selective inhibitors. The microcystin (MC) natural toxins target both phosphatases with equal potency, and their complex synthesis has complicated structure–activity relationship studies in the past. We report herein the synthesis and biochemical evaluation of 11 MC analogues, which was accomplished through an efficient strategy combining solid‐ and solution‐phase approaches. Our approach led to the first MC analogue with submicromolar inhibitory potency that is strongly selective for PP2A over PP1 and does not require the complex lipophilic Adda group. Through mutational and structural analyses, we identified a new key element for binding, as well as reasons for the selectivity. This work gives unprecedented insight into how selectivity between these phosphatases can be achieved with MC analogues.
Dynamic Odd–Even Effect in Liquid n‐Alkanes near Their Melting Points
Authors: Yang Ke , Cai Zhikun , Jaiswal Abhishek , Tyagi Madhusudan , Moore Jeffrey S. , Zhang Yang
Published: October 2016

n‐Alkanes are the textbook examples of the odd–even effect: The difference in the periodic packing of odd‐ and even‐numbered n‐alkane solids results in odd–even variation of their melting points. However, in the liquid state, in which this packing difference is not obvious, it seems natural to assume that the odd–even effect does not exist, as supported by the monotonic dependence of the boiling points of n‐alkanes on the chain length. Herein, we report a surprising odd–even effect in the translational diffusional dynamic properties of n‐alkanes in their liquid states. To measure the dynamics of the molecules, we performed quasi‐elastic neutron scattering measurements near their melting points. We found that odd‐numbered n‐alkanes exhibit up to 30 times slower dynamics than even‐numbered n‐alkanes near their respective melting points. Our results suggest that, although n‐alkanes are the simplest hydrocarbons, their dynamic properties are extremely sensitive to the number of carbon atoms.
High‐Density Liquid‐Crystalline Polymer Brushes Formed by Surface Segregation and Self‐Assembly
Authors: Mukai Koji , Hara Mitsuo , Nagano Shusaku , Seki Takahiro
Published: October 2016

High‐density polymer brushes on substrates exhibit unique properties and functions stemming from the extended conformations due to the surface constraint. To date, such chain organizations have been mostly attained by synthetic strategies of surface‐initiated living polymerization. We show herein a new method to prepare a high‐density polymer brush architecture using surface segregation and self‐assembly of diblock copolymers containing a side‐chain liquid‐crystalline polymer (SCLCP). The surface segregation is attained from a film of an amorphous base polymer (polystyrene, PS) containing a minor amount of a SCLCP‐PS diblock copolymer upon annealing above the glass‐transition temperature. The polystyrene portion of the diblock copolymer can work as a laterally mobile anchor for the favorable self‐assembly on the polystyrene base film.
Enantioselective Dearomative [3+2] Cycloaddition Reactions of Benzothiazoles
Authors: Wang Dong‐Chao , Xie Ming‐Sheng , Guo Hai‐Ming , Qu Gui‐Rong , Zhang Meng‐Cheng , You Shu‐Li
Published: October 2016

A highly enantioselective dearomative [3+2] cycloaddition of benzothiazole has been successfully developed. A wide range of benzothiazoles and cyclopropane‐1,1‐dicarboxylates are suitable substrates for this reaction. The desired hydropyrrolo[2,1‐b]thiazole compounds were obtained in excellent enantioselectivity and yields (up to 97 % ee and 97 % yield). With the same catalytic system, a highly efficient kinetic resolution of 2‐substituted cyclopropane‐1,1‐dicarboxylates was also realized.
Access to Acyclic Z‐Enediynes by Alkyne Trimerization: Cooperative Bimetallic Catalysis Using Air as the Oxidant
Authors: Lee Jin Tu Danence , Zhao Yu
Published: October 2016

Presented herein is a mild, operationally simple, mix‐and‐go procedure for the synthesis of acyclic trisubstituted Z‐enediynes, from readily available terminal alkynes, in good yields. This method stems from a serendipitous discovery, and makes use of cooperative palladium/copper bimetallic catalysis and air as an oxidant to effect an intriguing alkyne trimerization to yield the valuable Z‐enediyne moiety.
Non‐Porous Iron(II)‐Based Sensor: Crystallographic Insights into a Cycle of Colorful Guest‐Induced Topotactic Transformations
Authors: Rodríguez‐Jiménez Santiago , Feltham Humphrey L. C. , Brooker Sally
Published: October 2016

Materials capable of sensing volatile guests at room temperature by an easily monitored set of outputs are of great appeal for development as chemical sensors of small volatile organics and toxic gases. Herein the dinuclear iron(II) complex, [FeII2(L)2(CH3CN)4](BF4)4⋅2 CH3CN (1) [L=4‐(4‐methylphenyl)‐3‐(3‐pyridazinyl)‐5‐pyridyl‐4H‐1,2,4‐triazole], is shown to undergo reversible single‐crystal‐to‐single‐crystal (SCSC) transformations upon exposure to vapors of different guests: 1 (MeCN)⇌2 (EtOH)→3 (H2O)⇌1 (MeCN). Whilst 1 and 2 remain dimetallic, SCSC to 3 involves conversion to a 1D polymeric chain (due to a change in L bridging mode), which, remarkably, can undergo SCSC de‐polymerization, reforming dimetallic 1. Additionally, SC‐XRD studies of two ordered transient forms, 1TF3 and 2TF3, confirm that guest exchange occurs by diffusion of the new guests into the non‐porous lattices as the old guests leave. These reversible SCSC events also induce color and magnetic responses. Indeed dark red 1 is spin crossover active (T1/2↓ 356 K; T1/2↑ 369 K), whilst orange 2 and yellow 3 remain high spin.
Recognition‐Mediated Hydrogel Swelling Controlled by Interaction with a Negative Thermoresponsive LCST Polymer
Authors: Belal Khaled , Stoffelbach François , Lyskawa Joël , Fumagalli Matthieu , Hourdet Dominique , Marcellan Alba , Smet Lieselot De , de la Rosa Victor R. , Cooke Graeme , Hoogenboom Richard , Woisel Patrice
Published: October 2016

Most polymeric thermoresponsive hydrogels contract upon heating beyond the lower critical solution temperature (LCST) of the polymers used. Herein, we report a supramolecular hydrogel system that shows the opposite temperature dependence. When the non‐thermosesponsive hydrogel NaphtGel, containing dialkoxynaphthalene guest molecules, becomes complexed with the tetra cationic macrocyclic host CBPQT4+, swelling occurred as a result of host–guest complex formation leading to charge repulsion between the host units, as well as an osmotic contribution of chloride counter‐ions embedded in the network. The immersion of NaphtGel in a solution of poly(N‐isopropylacrylamide) with tetrathiafulvalene (TTF) end groups complexed with CBPQT4+ induced positive thermoresponsive behaviour. The LCST‐induced dethreading of the polymer‐based pseudorotaxane upon heating led to transfer of the CBPQT4+ host and a concomitant swelling of NaphtGel. Subsequent cooling led to reformation of the TTF‐based host–guest complexes in solution and contraction of the hydrogel.
Highly Efficient Cooperative Catalysis by CoIII(Porphyrin) Pairs in Interpenetrating Metal–Organic Frameworks
Authors: Lin Zekai , Zhang Zhi‐Ming , Chen Yu‐Sheng , Lin Wenbin
Published: October 2016

A series of porous twofold interpenetrated In‐CoIII(porphyrin) metal–organic frameworks (MOFs) were constructed by in situ metalation of porphyrin bridging ligands and used as efficient cooperative catalysts for the hydration of terminal alkynes. The twofold interpenetrating structure brings adjacent CoIII(porphyrins) in the two networks parallel to each other with a distance of about 8.8 Å, an ideal distance for the simultaneous activation of both substrates in alkyne hydration reactions. As a result, the In‐CoIII(porphyrin) MOFs exhibit much higher (up to 38 times) catalytic activity than either homogeneous catalysts or MOF controls with isolated CoIII(porphyrin) centers, thus highlighting the potential application of MOFs in cooperative catalysis.
Time‐Resolved In Situ X‐ray Diffraction Reveals Metal‐Dependent Metal–Organic Framework Formation
Authors: Wu Yue , Henke Sebastian , Kieslich Gregor , Schwedler Inke , Yang Miaosen , Fraser Duncan A. X. , O'Hare Dermot
Published: October 2016

Versatility in metal substitution is one of the key aspects of metal‐organic framework (MOF) chemistry, allowing properties to be tuned in a rational way. As a result, it important to understand why MOF syntheses involving different metals arrive at or fail to produce the same topological outcome. Frequently, conditions are tuned by trial‐and‐error to make MOFs with different metal species. We ask: is it possible to adjust synthetic conditions in a systematic way in order to design routes to desired phases? We have used in situ X‐ray powder diffraction to study the solvothermal formation of isostructural M2(bdc)2dabco (M=Zn, Co, Ni) pillared‐paddlewheel MOFs in real time. The metal ion strongly influences both kinetics and intermediates observed, leading in some cases to multiphase reaction profiles of unprecedented complexity. The standard models used for MOF crystallization break down in these cases; we show that a simple kinetic model describes the data and provides important chemical insights on phase selection.
Experimental investigation of the effects of crosslinking processes on the swelling and hygroscopic performances of a poly(vinyl alcohol) membrane
Authors: Gao Ying , Ye Hong , Wang Liwei , Liu Minghou
Published: October 2016

Poly(vinyl alcohol) (PVA) membranes crosslinked with L‐malic acid were prepared, and the effects of the heat‐treatment temperature and crosslinker concentration on their swelling and hygroscopic performances were investigated. Both the swelling and hygroscopic performances of the PVA membranes decreased with increasing heat‐treatment temperature; while the former decreased, the latter increased with increasing crosslinker concentration. The PVA membranes were characterized with differential scanning calorimetry (DSC), acid–base titration, and Fourier transform infrared spectrometry. The DSC results indicated that there was freezing and nonfreezing water in the swollen membranes, whereas there was only nonfreezing water in the moistened membranes. In addition, acid–base titration analysis revealed that both increased heat‐treatment temperature and increased crosslinker concentration increased the bilateral ester group levels (crosslinking degree) and decreased the content of freezing water. By contrast, the content of hydrophilic groups decreased and increased with increasing heat‐treatment temperature and crosslinker concentration, respectively; this resulted in decreased and increased levels of nonfreezing water, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2017,134, 44481.
Catalytically enhanced organic transistors for in vitro toxicology monitoring through hydrogel entrapment of enzymes
Authors: Strakosas Xenofon , Huerta Miriam , Donahue Mary J. , Hama Adel , Pappa Anna‐Maria , Ferro Magali , Ramuz Marc , Rivnay Jonathan , Owens Roisin M.
Published: October 2016

The regulation of cell metabolism is important for cell function and viability. In the presence of toxic compounds or pathogens, cell metabolism can change drastically because of excess stress on the cell. The monitoring of key metabolites, such as glucose and lactate, can provide insight into cellular function and can be used as a tool for toxicology studies. The development of enzymatic sensors based on organic electrochemical transistors (OECTs) was demonstrated in this study through the immobilization of enzymes in a photocrosslinkable hydrogel, which was, in turn, tethered to the platinum‐modified gate of a planar OECT. The resulting sensors exhibited high stability, sensitivity, and selectivity. The sensing of relevant metabolites in complex media collected from live kidney epithelial cells was performed. As a proof of the principle, the monitoring of glucose and lactate was also performed from cells treated with cisplatin, a known nephrotoxicant. The glucose and lactate monitoring show that the metabolism of cells was significantly altered by the presence of cisplatin. These findings support the monitoring of cell metabolism as a good approach for toxicology studies. They also illustrate the need for the development of enzymatic sensors that can be used in situ to monitor cell viability and function. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44483.
Effects of hydrosilyl monomers on the performance of polysiloxane encapsulant/phosphor blend based hybrid white‐light‐emitting diodes
Authors: Chang Chi‐Jung , Lai Chun‐Feng , Chiou Wei‐Yung , Reddy P. Madhusudhana , Su Min‐Ju
Published: October 2016

Polysiloxane‐based encapsulants were prepared by a hydrosilylation reaction of methacryl polyhedral oligomeric silsesquioxane and different hydrosilyl monomers. With the wavelength conversion method, white‐light‐emitting diodes (WLEDs) were produced by the application of a thermally cured polysiloxane encapsulant/phosphor composite as a wavelength converter on blue‐light‐emitting InGaN diodes. The color rendering index, the Commission Internationale de l'Éclairage coordinates, correlated the color temperature, and the luminous efficacy of the WLEDs with different encapsulants were evaluated. The effects of the chemical structures of hydrosilyl monomers on the optical, mechanical, and thermal resistance properties of the encapsulants, together with the performance of the WLEDs, were investigated. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44524.
Noise Induced DNA Damage Within the Auditory Nerve
Authors: Guthrie O'neil W.
Published: October 2016

An understanding of the molecular pathology that underlies noise induced neurotoxicity is a prerequisite to the design of targeted therapies. The objective of the current experiment was to determine whether or not DNA damage is part of the pathophysiologic sequela of noise induced neurotoxicity. The experiment consisted of 41 hooded Long‐Evans rats (2 month old males) that were randomized into control and noise exposed groups. Both the control and the noise group followed the same time schedule and therefore started and ended the experiment together. The noise dose consisted of a 6000 Hz noise band at 105 dB SPL. Temporal bones from both groups were harvested, and immunohistochemistry was used to identify neurons with DNA damage. Quantitative morphometric analyses was then employed to determine the level of DNA damage. Neural action potentials were recorded to assess the functional impact of noise induced DNA damage. Immunohistochemical reactions revealed that the noise exposure precipitated DNA damage within the nucleus of auditory neurons. Quantitative morphometry confirmed the noise induced increase in DNA damage levels and the precipitation of DNA damage was associated with a significant loss of nerve sensitivity. Therefore, DNA damage is part of the molecular pathology that drives noise induced neurotoxicity. Anat Rec, 300:520–526, 2017. © 2016 Wiley Periodicals, Inc.
The development of methods for the detection of Salmonella in chickens by a combination of immunomagnetic separation and PCRs
Authors: Dai Fengying , Zhang Miao , Xu Dixin , Yang Yin , Wang Jiaxiao , Li Mingzhen , Du Meihong
Published: October 2016

Micro‐ and nanoimmunomagnetic beads (MIMBs and NIMBs) used for immunomagnetic separation (IMS) with PCR were studied for the rapid detection of Salmonella. The capture efficiency of the two different IMBs was evaluated by a conventional plate counting method, and the binding pattern was studied using scanning electron microscopy. The specificity of the IMBs was tested with Salmonella, Shigella flexneri, enterohemorrhagic Escherichia coli O157:H7, and Listeria monocytogenes. By comparing the pre‐enrichment IMS and the IMS enrichment steps with a 5.5‐H enrichment time, this study developed a rapid and sensitive method for the detection of Salmonella in chicken. The method was implemented by IMS enrichment and PCR with MIMBs and NIMBs, with a total analysis time of 8 H. We showed that the method was sensitive based on NIMBs with a detection limit of 10° CFU for Salmonella in 25 g of chicken.
Common congenital anomalies: Environmental causes and prevention with folic acid containing multivitamins
Authors: Sarmah Swapnalee , Muralidharan Pooja , Marrs James A.
Published: October 2016

Congenital anomalies, congenital defects, or birth defects are significant causes of death in infants. The most common congenital defects are congenital heart defects (CHDs) and neural tube defects (NTDs). Defects induced by genetic mutations, environmental exposure to toxins, or a combination of these effects can result in congenital malformations, leading to infant death or long‐term disabilities. These defects produce significant mortality and morbidity in the affected individuals, and families are affected emotional and financially. Also, society is impacted on many levels. Congenital anomalies may be reduced by dietary supplements of folic acid and other vitamins. Here, we review the evidence for specific roles of toxins (alcohol, cigarette smoke) in causing common severe congenital anomalies like CHDs, NTDs, and ocular defects. We also review the evidence for beneficial effects for dietary supplementation, and highlight gaps in our knowledge, where research may contribute to additional benefits of intervention that can reduce birth defects. Extensive discussion of common severe congenital anomalies (CHDs, NTDs, and ocular defects) illustrates the effects of diet on the frequency and severity of these defects. Birth Defects Research (Part C) 108:274–286, 2016. © 2016 Wiley Periodicals, Inc.
Targeted modification of plant genomes for precision crop breeding
Authors: Hilscher Julia , Bürstmayr Hermann , Stoger Eva
Published: October 2016

The development of gene targeting and gene editing techniques based on programmable site‐directed nucleases (SDNs) has increased the precision of genome modification and made the outcomes more predictable and controllable. These approaches have achieved rapid advances in plant biotechnology, particularly the development of improved crop varieties. Here, we review the range of alterations which have already been implemented in plant genomes, and summarize the reported efficiencies of precise genome modification. Many crop varieties are being developed using SDN technologies and although their regulatory status in the USA is clear there is still a decision pending in the EU. DNA‐free genome editing strategies are briefly discussed because they also present a unique regulatory challenge. The potential applications of genome editing in plant breeding and crop improvement are highlighted by drawing examples from the recent literature.
Identification of peptide sequences that selectively bind to pentaerythritol trinitrate hemisuccinate‐a surrogate of PETN, via phage display technology
Authors: Kubas George , Rees William , Caguiat Jonathan , Asch David , Fagan Diana , Cortes Pedro
Published: October 2016

The present research investigates the identification of amino acid sequences that selectively bind to a pentaerythritol tetranitrate (PETN) explosive surrogate. Through the use of a phage display technique and enzyme‐linked immunosorbent assays (ELISA), a peptide library was tested against pentaerythritol trinitrate hemisuccinate (PETNH), a surrogate of PETN, to screen for those with amino acids having affinity toward the explosive. The results suggest that the library contains peptides selective to PETNH. Following three rounds of panning, clones were picked and tested for specificity toward PETNH. ELISA results from these samples show that each phage clone has some level of selectivity for binding to PETNH. The peptides from these clones have been sequenced and shown to contain certain common amino acid segments among them. This work represents a technological platform for identifying amino‐acid sequences selective toward any bio‐chem analyte of interest.