bluuebunny/crossref_metadata_2025 huggingface dataset:
Two‐Dimensional Tellurium Nanosheets Exhibiting an Anomalous Switchable Photoresponse with Thickness Dependence
Authors: Peng Jing , Pan Yu , Yu Zhi , Wu Jiajing , Wu Junchi , Zhou Yuan , Guo Yuqiao , Wu Xiaojun , Wu Changzheng , Xie Yi
Published: August 2018

Two‐dimensional (2D) tellurium (Te) was recently predicted to be promising for diverse electronic and optoelectronic applications. However, the synthesis of high‐quality 2D Te structures remains challenging, which greatly hinders the exploration of its full properties. Herein, an anomalous photoresponse from negative to positive as a function of thickness in Te nanosheets is reported. Ultrathin Te layers with large size and clean interface were obtained through a topotactic transformation, in which the 2D Te structure was derived from a layered MTe2 (M=Ti, Mo, W) matrix by excessive lithiation. Prominently, the photoresponse in Te nanosheets exhibits negative behavior when the thickness is less than 5 nm, which turns positive as the thickness increases. This unusual photoresponse will shed light on the full exploration of 2D non‐layered materials with exotic properties.
Ein neutraler η5‐Aminoborol‐Germanium(II)‐Komplex
Authors: Tholen Patrik , Dong Zhaowen , Schmidtmann Marc , Albers Lena , Müller Thomas
Published: August 2018

Die Synthese von zwei η5‐Aminoborol‐Germanium(II)‐Komplexen aus der Reaktion eines Germoldianions mit Aminobordichloriden wird beschrieben. Diese Reaktion liefert ein bemerkenswertes Beispiel für eine Germol‐zu‐Borol‐Transformation. Die beiden Aminoborol‐Germanium(II)‐Komplexe wurden vollständig durch Heterokern‐NMR‐, IR‐Spektroskopie, HR‐Massenspektrometrie und in einem Fall durch Röntgenkristallographie charakterisiert. Die Ergebnisse quantenmechanischer Rechnungen favorisieren die elektronische Struktur eines Halbsandwich‐Komplexes von GeII gegenüber einer ionischen Darstellung eines Germanium‐Dikations, welches durch ein aromatisches Aminoboroldianion stabilisiert wird.
Eine kurze Totalsynthese von Ajoen
Authors: Silva Filipa , Khokhar Shaista S. , Williams Danielle M. , Saunders Robert , Evans Gareth J. S. , Graz Michael , Wirth Thomas
Published: August 2018

Wir beschreiben eine kurze Totalsynthese von Ajoen, einem wichtigen biologisch aktiven Bestandteil von Knoblauch. Die Instabilität von Allicin, dem einzigen bekannten alternativen Ausgangsmaterial, hat zur Entwicklung eines zuverlässigen Protokolls für die Synthese von Ajoen aus einfachen Bausteinen geführt, welches sich auch für größere Mengen eignet.
Nickel‐Catalyzed Enantioconvergent Borylation of Racemic Secondary Benzylic Electrophiles
Authors: Wang Zhaobin , Bachman Shoshana , Dudnik Alexander S. , Fu Gregory C.
Published: August 2018

Nickel‐catalyzed cross‐coupling has emerged as the most versatile approach to date for achieving enantioconvergent carbon–carbon bond formation using racemic alkyl halides as electrophiles. In contrast, there have not yet been reports of the application of chiral nickel catalysts to the corresponding reactions with heteroatom nucleophiles to produce carbon–heteroatom bonds with good enantioselectivity. Herein, we establish that a chiral nickel/pybox catalyst can borylate racemic secondary benzylic chlorides to provide enantioenriched benzylic boronic esters, a highly useful family of compounds in organic synthesis. The method displays good functional group compatibility (e.g., being unimpeded by the presence of an indole, a ketone, a tertiary amine, or an unactivated alkyl bromide), and both of the catalyst components (NiCl2⋅glyme and the pybox ligand) are commercially available.
Spontaneous Metal‐Free Transfer Hydrogenation of Iminoboranes with Ammonia Borane and Amine Boranes
Authors: Winner Lena , Ewing William C. , Geetharani K. , Dellermann Theresa , Jouppi Brian , Kupfer Thomas , Schäfer Marius , Braunschweig Holger
Published: August 2018

The first spontaneous, metal‐free, room‐temperature hydrogen transfer from ammonia borane to an iminoborane is reported. Mechanistic studies of the reaction indicate a concerted transfer of H+ and H− from donor to acceptor with an activation energy far below those of comparable concerted transfer hydrogenations. This reaction was employed in the syntheses and isolation of new B,N‐disubstituted aminoboranes, a comparatively rare subset within the aminoborane family. This successful transfer hydrogenation to a highly dehydrogenated BN system may serve as a starting point for the design of new systems capable of reversible dehydrogenation/rehydrogenation.
Photoinduced Remote Functionalization of Amides and Amines Using Electrophilic Nitrogen Radicals
Authors: Morcillo Sara P. , Dauncey Elizabeth M. , Kim Ji Hye , Douglas James J. , Sheikh Nadeem S. , Leonori Daniele
Published: August 2018

The selective functionalization of C(sp3)−H bonds at distal positions to functional groups is a challenging task in synthetic chemistry. Reported here is a photoinduced radical cascade strategy for the divergent functionalization of amides and protected amines. The process is based on the oxidative generation of electrophilic amidyl radicals and their subsequent transposition by 1,5‐H‐atom transfer, resulting in remote fluorination, chlorination and, for the first time, thioetherification, cyanation, and alkynylation. The process is tolerant of most common functional groups and delivers useful building blocks that can be further elaborated. The utility of this strategy is demonstrated through the late‐stage functionalization of amino acids and a dipeptide.
A Neutral η5‐Aminoborole Complex of Germanium(II)
Authors: Tholen Patrik , Dong Zhaowen , Schmidtmann Marc , Albers Lena , Müller Thomas
Published: August 2018

The synthesis of two η5‐aminoborole complexes of germanium(II) from the reaction of a germole dianion with aminoboron dichlorides is reported. This reaction constitutes a remarkable example of a germole‐to‐borole transformation. The two aminoborole complexes of germanium(II) were fully characterized by multinuclear NMR spectroscopy, IR spectroscopy, HRMS, and, in one case, by X‐ray crystallography. The results of quantum‐mechanical calculations favor the electronic structure of a half‐sandwich complex of GeII over an ionic representation with a germanium dication stabilized by an aromatic aminoborole dianion.
Surfactant‐directed one‐pot preparation of novel Ti‐containing mesomaterial with improved catalytic activity and reusability
Authors: Elhamifar Dawood , Yari Omolbanin , Hajati Shaaker
Published: August 2018

Titanium was incorporated in ionic liquid based periodic mesoporous organosilica to prepare a nanostructured catalyst (Ti@PMO‐IL) with high activity. Procedure for the synthesis of Ti@PMO‐IL was followed according the simultaneous hydrolysis and condensation of alkylimidazolium ionic liquid, tetramethoxysilane (TMOS) and tetrabutylorthotitanate (TBOT) where a surfactant template was used together with a simple acid‐based catalytic aproach. N2 adsorption isotherm of the Ti@PMO‐IL was studied to measure its mean pore volume, pore size distribution and specific surface area. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was applied to identify the chemical bonds present in Ti@PMO‐IL. The morphology of this nanomaterial was investigated by scanning electron microscopy (SEM). Transmission electron microscopy (TEM) image was used to study mesoporosity and structure order of the catalyst. The catalytic activity of Ti@PMO‐IL was then studied and found to be efficient and reusable to catalyze Hantzsch reaction.
A new polymer field effect transistor based on fluorene derivative with fused furan rings
Authors: He Yang , Xiao Mingchao , Liu Ye , Zhang Xi , Jiang Lang , Liu Hui , Zou Yingping
Published: August 2018

Composed of novel monomer (10,10‐dihexyl‐10‐fluoreno[2,3‐b:7,6‐b′]difuran‐2,7‐diyl)bis(tri‐methylstannane) (DFF) and commercial 2,5‐di(2‐ethylhexyl)‐3,6‐di(5‐bromothiophen‐2‐yl)diketopyrrolopyrrole (DPP32), PDFFDPP32 is synthesized and systematically characterized by high‐temperature gel‐permeation chromatography, thermogravimetric analysis, ultraviolet–visible absorption, Fourier transform infrared spectroscopy, and cyclic voltammetry testing. The resulting polymer displays good hole transport behaviors in bottom gate/top contact organic field effect transistors (OFET) with hole mobility up to 6.42 × 10−3 cm2 V−1 s−1. The rough surface morphology of the polymer films is characterized by atomic force microscopy, and the polymer films are in an amorphous state, as demonstrated by X‐ray diffraction. The intra‐ and interchain O···S noncovalent interactions, as verified by X‐ray photoelectron spectroscopy, possibly endow the polymer with enhanced interactive forces among the polymeric chains. The results indicate that PDFFDPP32 has potential applications in OFET, and the novel monomer DFF has prospects for building high‐performance organic optoelectronic materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46865
Effects of doping aluminum chloride on stabilization and properties of polyacrylonitrile‐based carbon fibers
Authors: Chen Li , Lu Chunxiang , Jiang Junqi , Huang Fei , Li Hong , Lu Yonggen
Published: August 2018

Polyacrylonitrile (PAN) gel fibers were immersed in 0–2.0 wt % aluminum chloride (AlCl3) aqueous solutions to fabricate Al‐doped PAN fibers and the resultant carbon fibers (CFs) on a continuous production line, and the effects of doping with AlCl3 on the stabilization and properties of PAN‐based CFs were investigated. The Al content in the PAN fibers and in the resultant CFs is 2800 and 5700 ppm, respectively, at 2.0 wt % doping solution concentration. Al compound particles were speculated to exist in the pores of PAN fibers, and they show strong inhibiting effects on both cyclization and oxidation reactions. However, the disadvantages can be overcome by a longer stabilization period or a higher stabilization temperature to produce CFs that have comparable mechanical properties with 2.98–3.20 GPa tensile strength and 210–220 GPa Young's modulus. Thermogravimetric analysis in air shows the weight of CFs increases remarkably from 19.0% to 59.3% at 850°C for Al content 0–1900 ppm, while it gradually decreases over 1900–5700 ppm.
Effect of electronegativity and steric hindrance of the cocatalyst on the activity and selectivity of butadiene polymerization catalyzed by molybdenum
Authors: Liu Jinhui , Geng Jieting , Liu Kai , Zou Lingli , Wang Zhaobo , Hua Jing
Published: August 2018

Molybdenum‐based random 1,2‐polybutadiene (1,2‐PB) rubber, with its excellent wet skid resistance, low rolling resistance, and low heat buildup, can be used for green tread rubber, and it has significant benefits for the enhancement of the mechanical strength of 1,2‐PB. In this study, we investigated in detail the effects of the electronegativity and steric hindrance of the cocatalyst on the stereoselectivity of the resulting polymers. In the case of cocatalysts with moderate electronegativities, the active centers were more stable; this resulted in a larger molecular weight and a higher conversion, whereas a cocatalyst with excessive electronegativity tended to initiate cationic polymerization. The high sterically hindered substituent restricted the coordination configuration of the monomer; this ultimately resulted in the increase in the 1,2 structure to 90%. Fourier transform infrared analysis showed that the content of trans‐1,4 structure increased from 7 to 66%, and its crystallinity reached 59.2%, as calculated with differential scanning calorimetry when triethyl aluminum was used as the cocatalyst. Consequently, trans‐1,4‐polybutadiene crystals were introduced into the 1,2‐PB elastomer in one step; this could be a promising facile route for strengthening 1,2‐PB. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46906.
Influence of solubility parameter difference between monomer and porogen on structures of poly (acrylonitrile–styrene‐divinylbenzene) resins
Authors: Cai Yuanbo , Yan Wu , Peng Xuesong , Liang Mei , Yu Lin , Zou Huawei
Published: August 2018

In this work, the acrylonitrile (AN)‐styrene (St)‐divinylbenzene (DVB) resin was synthesized via suspension polymerization in the presence of inert porogens as diluent. The relationship of the solubility parameter (SP) of the materials and the porous properties of the resin was investigated. These porous spherical resin particles (0.25–0.84 mm) can be used as precursors of amidoxime resin which has a high metal ion chelating efficiency. The results showed that the porous properties (surface area and mean pore width) of the resin changed with variation in the compatibility between monomers and porogens. According to the the BET theory to N2 sorption and scanning electron microscopy (SEM), the specific surface area of the obtained beads was strongly dependent on the compatibility of the components of the system and achieved values from 3.3 to 66.8 m2/g. The surface area of the terpolymer beads was found to rise with a decrease in the content of acrylonitrile or an increase in the SP of the porogens. However, the variation of the pore size was just the opposite. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46979.
Predicting the fate of the most endangered marine invertebrate of the Mediterranean: The power of long‐term monitoring in conservation biology
Authors: Espinosa Free , Rivera‐Ingraham Georgina A. , Ostalé‐Valriberas Enrique , García‐Gómez José C.
Published: August 2018

Global climate change and other human‐induced alterations of the environment are causing a significant loss in biodiversity. Among the many species affected is the giant limpet Patella ferruginea, considered as the most endangered marine invertebrate within the Western Mediterranean basin.

The results of a 10‐year monitoring programme in an updated population viability analysis (PVA) model are provided, which indicate the unlikeliness of the population in Ceuta facing extinction within the next 50 years.

Evidence is provided for the possible role of this population as a source population for other sink populations in the Alboran Sea.

Large interannual variations in recruitment have been recorded, and the general linear model (GLM) indicates the influence of chlorophyll and temperature on recruitment rates. These results inform conservation strategies for this flagship species.
Properties of a novel carboxymethyl chitosan derived from silkworm pupa
Authors: Zhu Lin , Zou De‐Qing , Fan Zuo‐Qing , Wang Na , Bo Ying‐Ying , Zhang Yu‐Qing , Guo Guang
Published: August 2018

In this study, a carboxymethyl chitosan derived from silkworm pupa (SP‐carboxymethyl chitosan) was prepared. The physical characteristics of the SP chitin, chitosan, and carboxymethyl chitosan were analyzed. The scanning electron microscopy results showed that the surfaces of the samples from SP were more uneven, with more surface fractures compared with those of the reference substance (RS). Thermal analysis, X‐ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy analysis showed that the main molecular chain structures of SP samples and RSs had no substantial differences. However, the crystallinity and thermal decomposition temperature of the SP samples were lower compared with those of the RSs. All of these results provide a theoretical basis for the development of applications for the SP‐carboxymethyl chitosan.
Libcitations, worldcat, cultural impact, and fame
Authors: White Howard D. , Zuccala Alesia A.
Published: August 2018

Just as citations to a book can be counted, so can that book's libcitations—the number of libraries in a consortium that hold it. These holdings counts per title can be obtained from the consortium's union catalog, such as OCLC's WorldCat. Librarians seeking to serve their customers well must be attuned to various kinds of merit in books. The result in WorldCat is a great variation in the libcitations particular books receive. The higher a title's count (or percentile), the more famous it is—either absolutely or within a subject class. Degree of fame also indicates cultural impact, allowing that further documentation of impact may be needed. Using WorldCat data, we illustrate high, medium, and low degrees of fame with 170 titles published during 1990–1995 or 2001–2006 and spanning the 10 main Dewey classes. We use their total libcitation counts or their counts from members of the Association of Research Libraries, or both, as of late 2011. Our analysis of their fame draws on the recognizability of their authors, the extent to which they and their authors are covered by Wikipedia, and whether they have movie or TV versions. Ordinal scales based on Wikipedia coverage and on libcitation counts are very significantly associated.
Nonlinear MPC for a Sensorless Multi‐Vectored Propeller Airship Based on Sliding Mode Observer with Saturation
Authors: Wen Yubin , Chen Li , Liang Kuankuan , Duan Dengping
Published: August 2018

A nonlinear fault tolerant station keeping controller for a multi‐vectored propeller airship without velocity and angular velocity sensors is developed, which is composed of three modules: nonlinear model predictive controller (NMPC), sliding mode observer (SMO), and linear programming (LP) based control allocation. The kinematics and dynamics model of the airship are introduced. Based on the nonlinear model, with the assumption that the velocity and angular velocity sensors are damaged, a sliding mode observer is designed to estimate the velocity and angular velocity of the airship. To achieve good performance in the station keeping mission, an explicit nonlinear model predictive control is derived. A linear programming base control allocation method is proposed to solve both amplitude and rate constraint of the propulsion forces and deflection angles. Stability analysis is carried out to prove that the system can be stabilized in finite time. Simulation results for the station keeping control are illustrated to prove the effectiveness of the proposed method.
Offline Robust Model Predictive Control for Lipschitz Non‐Linear Systems Using Polyhedral Invariant Sets
Authors: Shokrollahi Ali , Shamaghdari Saeed
Published: August 2018

In this paper the concept of maximal admissible set (MAS) for linear systems with polytopic uncertainty is extended to non‐linear systems composed of a linear constant part followed by a non‐linear term. We characterize the maximal admissible set for the non‐linear system with unstructured uncertainty in the form of polyhedral invariant sets. A computationally efficient state‐feedback RMPC law is derived off‐line for Lipschitz non‐linear systems. The state‐feedback control law is calculated by solving a convex optimization problem within the framework of linear matrix inequalities (LMIs), which leads to guaranteeing closed‐loop robust stability. Most of the computational burdens are moved off‐line. A linear optimization problem is performed to characterize the maximal admissible set, and it is shown that an ellipsoidal invariant set is only an approximation of the true stabilizable region. This method not only remarkably extends the size of the admissible set of initial conditions but also greatly reduces the on‐line computational time. The usefulness and effectiveness of the method proposed here is verified via two simulation examples.
Smart Water Meters and Data Analytics Decrease Wasted Water Due to Leaks
Authors: Schultz Wesley , Javey Shahram , Sorokina Alla
Published: August 2018

Advanced metering infrastructure (AMI) allows for hour‐by‐hour monitoring of water usage and has created new opportunities to communicate with customers. This article summarizes the results from a large‐scale deployment of an AMI system with more than 85,000 residential customers. Households were provided with access to a secure customer online portal where they could view their consumption information, use a leak detection algorithm to monitor their consumption patterns, and set alerts when a potential leak was detected. Analyses showed that, subsequent to signup, households that accessed the customer portal were less likely to have a leak, and when a leak did occur, they repaired it more quickly, compared with similar households that did not sign up for online access. The results provide strong evidence for the value of leak detection analytics and alerts at minimizing water loss and damage due to leaks.
A 2017 global update on folic acid‐preventable spina bifida and anencephaly
Authors: Kancherla Vijaya , Wagh Kaustubh , Johnson Quentin , Oakley Godfrey P.
Published: August 2018

Background

Spina bifida and anencephaly are largely preventable birth defects through mandatory folic acid fortification. Our objective was to estimate the proportion of folic acid‐preventable spina bifida and anencephaly (FAP SBA) prevented worldwide through mandatory fortification of wheat and/or maize flour with folic acid during the year 2017.

Methods

Using existing data, we identified countries with mandatory fortification policies that added at least 1.0 ppm folic acid to wheat and/or maize flour and had information on percentage of industrially milled flour that is fortified. We assumed mandatory folic acid fortification at 200 μg/day of folic acid fully protects against FAP SBA, reducing the prevalence of spina bifida and anencephaly to 0.5 per 1,000 live births.

Results

Overall, 59 countries met our criteria for implementing mandatory folic acid fortification of wheat and/or maize flour in 2017. These countries prevented about 50,270 out of 280,500 FAP SBA births in 2017. Thus, we have only achieved 18% prevention of FAP SBA worldwide. Several countries in Africa and Asia with a high number of FAP SBA‐affected births do not have mandatory fortification.

Conclusion

About 230,000 children unnecessarily developed FAP SBA globally in 2017. There is an urgent need for all countries to implement mandatory folic acid fortification, a proven, safe public health intervention that saves money and prevents infant mortality and disability. Prevention of FAP SBA can play an important role in helping countries to achieve their Sustainable Development Goals for health.
The Actomyosin Cytoskeleton Drives Micron‐Scale Membrane Remodeling In Vivo Via the Generation of Mechanical Forces to Balance Membrane Tension Gradients
Authors: Ebrahim Seham , Liu Jian , Weigert Roberto
Published: August 2018

The remodeling of biological membranes is crucial for a vast number of cellular activities and is an inherently multiscale process in both time and space. Seminal work has provided important insights into nanometer‐scale membrane deformations, and highlighted the remarkable variation and complexity in the underlying molecular machineries and mechanisms. However, how membranes are remodeled at the micron‐scale, particularly in vivo, remains poorly understood. Here, we discuss how using regulated exocytosis of large (1.5–2.0 μm) membrane‐bound secretory granules in the salivary gland of live mice as a model system, has provided evidence for the importance of the actomyosin cytoskeleton in micron‐scale membrane remodeling in physiological conditions. We highlight some of these advances, and present mechanistic hypotheses for how the various biochemical and biophysical properties of distinct actomyosin networks may drive this process.
Blinded and unblinded sample size reestimation procedures for stepped‐wedge cluster randomized trials
Authors: Grayling Michael J. , Mander Adrian P. , Wason James M. S.
Published: August 2018

The ability to accurately estimate the sample size required by a stepped‐wedge (SW) cluster randomized trial (CRT) routinely depends upon the specification of several nuisance parameters. If these parameters are misspecified, the trial could be overpowered, leading to increased cost, or underpowered, enhancing the likelihood of a false negative. We address this issue here for cross‐sectional SW‐CRTs, analyzed with a particular linear‐mixed model, by proposing methods for blinded and unblinded sample size reestimation (SSRE). First, blinded estimators for the variance parameters of a SW‐CRT analyzed using the Hussey and Hughes model are derived. Following this, procedures for blinded and unblinded SSRE after any time period in a SW‐CRT are detailed. The performance of these procedures is then examined and contrasted using two example trial design scenarios. We find that if the two key variance parameters were underspecified by 50%, the SSRE procedures were able to increase power over the conventional SW‐CRT design by up to 41%, resulting in an empirical power above the desired level. Thus, though there are practical issues to consider, the performance of the procedures means researchers should consider incorporating SSRE in to future SW‐CRTs.
In Silico Processing of the Complete CRISPR‐Cas Spacer Space for Identification of PAM Sequences
Authors: Mendoza Brian J. , Trinh Cong T.
Published: August 2018

Despite extensive exploration of the diversity of CRISPR‐Cas (Clustered Regularly Interspaced Short Palindromic Repeats, CRISPR associated) systems, biological applications have been mostly confined to Class 2 systems, specifically the Cas9 and Cas12 (formerly Cpf1) single effector proteins. A key limitation of exploring and utilizing other CRISPR‐Cas systems with unique functionalities, particularly Class I types and their multi‐protein effector complex, is the knowledge of the system's protospacer adjacent motif (PAM) sequence identity. In this work, the authors developed a systematic pipeline, named CASPERpam, that enables a comprehensive assessment of the PAM sequences of all the available CRISPR‐Cas systems in the NCBI database of bacterial genomes. The CASPERpam analysis reveals that within the 30 389 assemblies previously screened for CRISPR arrays, there exists 26 364 spacers that match somewhere in the viral, bacterial, and plasmid databases of NCBI, using the constraints of 95% sequence identity and 95% sequence coverage for blast hits. When grouping these results by species, the authors identified putative PAM sequences for 1049 among 1493 unique species. The remaining species either have insufficient data or an undetermined result from the analysis. Finally, the authors assigned a confidence score to each species’ PAM prediction and generate categories that largely cover the revealed diversity of PAM motifs, providing a baseline for further experimental studies including PAM assays. The authors envision CASPERpam is a useful bioinformatic tool for understanding and harnessing the diversity of CRISPR‐Cas systems.
Dinoflagellaten – ein Dauerexperiment der Evolution?
Authors: Hoppenrath Mona , Saldarriaga Juan , Tillmann Urban
Published: August 2018

Dinoflagellaten sind wichtige Mitglieder mariner Nahrungsnetze, sowohl als Primärproduzenten als auch als heterotrophe Konsumenten. Sie verursachen spektakuläre Phänomene wie Meeresleuchten und rote Tiden, sind wesentliche Bestandteile von Korallenriffen und können einige der giftigsten natürlichen Biotoxine synthetisieren. Dinoflagellatenzellkerne sind extrem groß und biochemisch einzigartig, während ihre Mitochondriengenome sehr klein sind. Die Plastidendiversität der Dinoflagellaten ist einzigartig: nur etwa die Hälfte der Arten der Gruppe betreibt Photosynthese, und deren Plastiden haben sehr unterschiedliche Ursprünge und infolgedessen sehr verschiedene physiologische und biochemische Eigenheiten. Einige der kompliziertesten morphologischen Gebilde, die überhaupt von Einzellern bekannt sind, finden sich in dieser Gruppe. Dazu gehören z. B. „Harpunen“ zum Beutefang, oder „Augen“ mit subzellulären Strukturen, die Linse, Kornea und Pigmentbecher ähneln.
Preparation and Photocatalytic Activity of ABi2O6/BiOCl (A = Mg, Sr, Ca) Heterojunction
Authors: Huang Zhenyu , Wang Yan , Jung Dongwoon
Published: August 2018

MgBi2O6, CaBi2O6, and SrBi2O6 were successfully synthesized by a substitution reaction of NaBiO3 with MgCl2, CaCl2, and Sr(NO3)2, respectively. Then, ABi2O6/BiOCl (A = Mg, Ca, Sr) heterojunction compounds with different ABi2O6:BiOCl ratios were prepared by treating ABi2O6 with an appropriate amount of HCl. The color of the ABi2O6/BiOCl heterojunction was changed from dark to bright as the amount of BiOCl was increased. The absorbances of the ABi2O6/BiOCl heterojunctions in the visible range were decreased as the ratio of BiOCl became higher. The photocatalytic activities of the heterojunction samples were higher than that of sole ABi2O6 or BiOCl. The highest photocatalytic efficiency was achieved when the ABi2O6:BiOCl ratio was 15:85. The organic pollutant was decomposed completely within 1 h under visible light when the 15:85 catalyst was used. The reactive species in the photocatalytic reaction with the ABi2O6/BiOCl photocatalysts were ·O2‐ and h+ H+.
Influence of p‐Type Double‐Doping on the Crystals and Electronic Structures of Two Polar Intermetallics: La4.57(1)Li0.43Ge3.80(3)In0.20 and Nd4.32(1)Li0.68Ge3.87(3)In0.13
Authors: Jeon Jieun , Lee Junsu , You Tae‐Soo
Published: August 2018

Two quaternary polar intermetallic compounds La4.57(1)Li0.43Ge3.80(3)In0.20 and Nd4.32(1)Li0.68Ge3.87(3)In0.13 were synthesized using a conventional high temperature synthetic method as we attempted to introduce the p‐type double‐doping of Li and In for RE and Ge in the RE5‐xLixGe4‐y (RE = rare‐earth metals) system, and their crystal structures were characterized by single crystal X‐ray diffraction experiments. The two title compounds crystallize in the orthorhombic space group Pnma (Pearson code oP16, Z = 4) with six crystallographically independent asymmetric atomic sites and adopt the Gd5Si4‐type structure. Overall crystal structures of two isotypic title compounds can be described as a 1:1 assembly of the hypothetical 2‐dimensional (2D) RE2(RE/Li)(In/Ge)2 layered structure adopting the Mo2FeB2‐type structure and the dumbbell‐shaped inter‐slab (In/Ge)2 dimers bridging two such neighboring 2D layers along the crystallographic b‐axis direction. The observed “direction selective” structural transformation from the Sm5Ge4‐type to the Gd5Si4‐type structure can be understood as a result of the simultaneous double‐doping by the relatively smaller amount of Li substitution for La at the RE3 site than that in the La4LiGe4 and the partial In substitution for Ge at both of the M1 and M3 sites. The site‐preference of In for two particular anionic sites were thoroughly studied using four hypothetical La4LiGe3In models having different atomic arrangements by the tight‐binding linear muffin‐tin orbital (TB‐LMTO) method. The overall electronic structure and individual chemical bonding influenced by the given double‐doping were also discussed on the basis of the density of states (DOS) and crystal orbital Hamilton population (COHP) curves analyses.
Development of an LC‐MS/MS‐based assay to determine artemitin in rat plasma and its application in a pharmacokinetic study
Authors: Han Xiaoli , He Jinhua , Chen Qinyue , Sun Yali , Zhang Xiulei , Gu Zhengyi , Sha Xianyi
Published: August 2018

Artemitin, a significant flavonol compound existing in Laggera pterodonta (DC.) Benth., Artemisia rupestris L, etc., is the subject of attention by researchers owing to its pharmacological activities (such as antioxidative, anti‐inflammatory and antiviral). In this work, a highly sensitive and specific high‐performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC‐ESI‐MS/MS) assay combined with protein precipitation has been established and validated for determining artemitin concentration in rat plasma. Both artemitin and warfarin sodium (internal standard, IS) were separated on an Agela Venusil XBP Phenyl column through the isocratic elution mode of methanol–water containing 0.1% formic acid (80:20, v/v), at a flow rate of 0.4 mL/min. The MS/MS system was operated in a positive ion and ESI multiple reaction monitoring mode, and the multiple reaction monitoring transition was optimized as m/z 389.0 → 373.0 for artemitin and 309.2 → 163.0 for IS. The method showed good linearity in the range of 2.5–2000 ng/mL (R2 = 1.0000) and high sensitivity for artemitin with the lower limit of quantification of 2.5 ng/mL. The intra‐ and inter‐day accuracies were 97.4–100.9 and 93.4–100.3%, respectively. The intra‐ and inter‐day precisions were <4.8 and 6.5%, respectively. The extraction efficiency and absolute recovery were >66.5 and 71.3%, respectively. In addition, a good matrix effect of <9.5% was obtained. As a result, the method developed herein was successfully applied for the pharmacokinetic study of artemitin after an intravenous administration in rats.
Key elements in assessing circular economy implementation in small and medium‐sized enterprises
Authors: Prieto‐Sandoval Vanessa , Ormazabal Marta , Jaca Carmen , Viles Elisabeth
Published: August 2018

The circular economy has become an important issue in recent years because it makes sustainable development feasible by creating value in the economy and by closing the energy and materials loops. However, since most companies continue to operate under a linear model, it is particularly important to start providing companies with tools that facilitate their shift to the circular paradigm. The main objective of this research is to establish the key elements that are necessary for assessing the level of circular economy implementation. To that end, the Delphi method is used to validate and define the key elements of three categories: circular economy fields of action, industrial symbiosis, and environmental certifications. As a result, this study identifies the key elements that assess the degree of circular economy implementation and that allows small and medium‐sized enterprises to understand where they are and what they need to do to improve their performance.
Does competition prevent industrial pollution? Evidence from a panel threshold model
Authors: Polemis Michael L. , Stengos Thanasis
Published: August 2018

The objective of this paper is to assess the impact of competition on industrial toxic pollution by using, for the first time, a panel threshold model which allows evaluations of the main drivers of toxic releases under two different market regimes. The empirical analysis is based on a micro‐level panel dataset over the five‐year period 1987–2012. We show that this relationship is statistically significant and robust above and below the threshold, even after accounting for alternative specifications of market concentration. Specifically, we unmask an inverted V‐shaped relationship between market concentration and industrial pollution. We argue that the increasing non‐parametric regression line up to a certain concentration (threshold) level indicates a negative effect on facilities' emissions levels, whereas a decreasing line indicates a positive effect. This relationship provides new insights into environmental policy design towards abatement of industrial releases and sustainability. Finally, our empirical model remains robust under different specifications properly accounted for possible endogeneity.
Method of establishing breast cancer brain metastases affects brain uptake and efficacy of targeted, therapeutic nanoparticles
Authors: Wyatt Emily A. , Davis Mark E.
Published: August 2018

HER2‐targeted therapies effectively control systemic disease, but their efficacy against brain metastases is hindered by their low penetration of the blood‐brain and blood‐tumor barriers (BBB and BTB). We investigate brain uptake and antitumor efficacy of transferrin receptor (TfR)‐targeted, therapeutic nanoparticles designed to transcytose the BBB/BTB in three murine models. Two known models involving intracranial (IC) or intracardiac (ICD) injection of human breast cancer cells were employed, as was a third model developed here involving intravenous (IV) injection of the cells to form whole‐body tumors that eventually metastasize to the brain. We show the method of establishing brain metastases significantly affects therapeutic BBB/BTB penetration. Free drug accumulates and delays growth in IC‐ and ICD‐formed brain tumors, while non‐targeted nanoparticles show uptake and inhibition only in IC‐established metastases. TfR‐targeted nanoparticles accumulate and significantly delay growth in all three models, suggesting the IV model maintains a more intact BBB/BTB than the other models.
Matrine induces senescence of human glioblastoma cells through suppression of the IGF1/PI3K/AKT/p27 signaling pathway
Authors: Zhou Wenjing , Wang Jiwei , Qi Qichao , Feng Zichao , Huang Bin , Chen Anjing , Zhang Di , Li Wenjie , Zhang Qing , Bjerkvig Rolf , Li Xingang , Wang Jian
Published: August 2018

Background

Matrine, a traditional Chinese medicine, has recently been shown to have antitumor properties in diverse cancer cells. Here, we explored the effect of matrine on human glioblastoma multiforme (GBM) cells.

Methods

Glioblastoma multiforme cell lines were treated with matrine to assess proliferation and viability using EdU and CCK8 assays. SA‐β‐gal assays were used to evaluate cellular senescence, and a cytokine array and ELISA assay were used to screen for secreted cytokines altered in GBM cells after matrine treatment. Immunohistochemistry and Western blot analysis were performed to evaluate protein levels in matrine‐treated cell lines and in samples obtained from orthotopic xenografts. Specific activators of AKT and IGF1 were used to identify the pathways mediating the effect.

Results

Matrine potently inhibited growth of GBM cell lines in vitro. Based on in situ assays, growth arrest induced by matrine was primarily achieved through induction of cellular senescence. Matrine treatment led to decreased expression of proteins involved in promoting cell growth, IGF1, PI3K, and pAKT. Exposure of cells to a small molecule activating AKT (SC79) and recombinant IGF1 led to a reduced number of senescent SA‐β‐gal‐positive cells in the presence of matrine. Finally, matrine inhibited growth of orthotopic xenografts established from luciferase‐stable‐U251 or luciferase‐stable‐P3 cells and prolonged overall survival in mice.

Conclusions

These results indicated that matrine arrested cell growth through inhibition of IGF1/PI3K/AKT signaling. Matrine warrants further investigation as a potential therapy in the treatment of patients with GBM.
Keep your eye on…
Authors: Knopf Alison
Published: August 2018

Use of Concerta for mood symptoms of DMDD with comorbid ADHD

Screening children with abdominal pain for anxiety

The lack of adjustment problems for children with same‐sex parents
Teens from all socioeconomic categories use substances: Parents are the deciding factor
Authors: Knopf Alison
Published: August 2018

An “Emerging Drug Trends” report from the Hazelden Betty Ford Institute for Recovery Advocacy describes the results of recent studies that show that socioeconomic status and other environmental factors affect the kind of substance use teens engage in. While excessive drinking disproportionately affects upper‐middle‐class families (Luthar et al., 2017), the acceptance of marijuana in school is more likely to predict a teen's use of marijuana (Milliren et al., 2017).
Who can we save after an intraprocedural catastrophe during TAVR?
Authors: Satler Lowell , Thourani Vinod H.
Published: August 2018

KEY POINTS

Intraprocedural catastrophes during transcatheter aortic valve replacement (TAVR) are associated with a high mortality.

Even “operable patients” can suddenly be deemed inoperable during an intraprocedural TAVR complication.

The low incidence of a major complication prevents “crowd learning”; consequently, a high‐volume TAVR center will have the greatest capability for a robust salvage response.
SYNTAX II in the “real world” – A practical approach to coronary risk‐stratification
Authors: Reimold Fabian R. , Levy Michael S.
Published: August 2018

Key Points

The SYNTAX II score is valid in the real world, and can be applied to international patient cohorts

It is an independent predictor of overall mortality and other cardiovascular endpoints

It is a practical tool for coronary risk stratification given its inclusion of pertinent clinical data in addition to anatomic data
The impact of the Rht‐B1b, Rht‐D1b, and Rht‐8 wheat semi‐dwarfing genes on flour milling, baking, and micronutrients
Authors: Jobson Emma M. , Martin John M. , Schneider Tavin M. , Giroux Michael J.
Published: August 2018

Background and objectives

The introduction of the semi‐dwarfing Reduced Height (Rht) genes in wheat led to dramatic yield increases. The two most common forms of the gene, Rht‐B1b and Rht‐D1b have been widely incorporated into wheat varieties. However, despite their agronomic benefits and prevalence in modern wheat cultivars, much less is known regarding their impact on end‐use quality and nutrition. For this study, we compared near‐isogenic lines (NILs) carrying either Rht‐B1b, Rht‐D1b, Rht‐8 or no semi‐dwarfing alleles.

Findings

Our agronomic results agreed with previous studies; we observed a 25% height reduction, 13% yield increase, and a 2% decrease in grain protein content in the semi‐dwarf NILs. However, despite the decreased protein content, the Rht‐B1b/Rht‐D1b NILs had increased bake mixing time (33%), but reduced loaf volume (7%). We also observed that although the semi‐dwarfing alleles decreased kernel weight by 15%, they were associated with a 2% increase in flour yield. Flours prepared from the semi‐dwarf NILs had decreased Zinc, Iron, and Manganese while having increased levels of Potassium and Calcium.

Conclusions

These findings demonstrate that while Rht‐B1b/Rht‐D1b negatively impact kernel size and protein content they positively impact flour yield and dough mixing strength.

Significance and novelty

The most common wheat semi‐dwarf alleles decrease kernel size, protein, and micronutrient content while increasing flour yield.
Effects of Charge, Size, and Shape of Transition States, Bound Intermediates, and Confining Voids in Reactions of Alkenes on Solid Acids
Authors: Sarazen Michele L. , Iglesia Enrique
Published: August 2018

Solid acids with sites varying in acid strength and in confining environments are used here to examine, through kinetic experiments and theory, how size and shape of organic guests and inorganic hosts at ion‐pair transition states (TS) influence reactivity. Reactions of C2−C4 alkene mixtures serve as the illustrative example; they involve kinetically‐relevant C−C coupling between alkenes and bound alkoxides that saturate the surface on microporous (TON) and mesoporous (SiAl) aluminosilicates of similar acid strength and on stronger heteropolytungstic acids (HPW). Rate constants (per H+) increase with increasing TS size (number of C‐atoms) because of the combined effects of size/substitution on proton affinities of coupling products and on van der Waals (vdW) contacts between carbocations and voids. When the voids and organic moieties are similar in dimension, these contacts require framework distortions, leading to dispersive interactions that are compensated in part by enthalpic penalties associated with the distortions, which are quantified here with DFT‐derived atomic displacements and distortion energies. DFT‐derived proton affinities of the coupling products and vdW interaction energies between the TS and voids represent the most accurate and complete descriptors of reactivity, as the size and shape of TS structures vary in C−C coupling steps and more generally in acid‐catalyzed transformations, and can be used in designing voids for stabilizing specific host‐guest pairs.
Investigations on Catalyst Stability and Product Isolation in the Extractive Oxidative Desulfurization of Fuels Using Polyoxometalates and Molecular Oxygen
Authors: Bertleff Benjamin , Goebel Rebecca , Claußnitzer Johannes , Korth Wolfgang , Skiborowski Mirko , Wasserscheid Peter , Jess Andreas , Albert Jakob
Published: August 2018

Our contribution adds important new insight to the recent finding that polyoxometalate catalysts, such as H8PV5Mo7O40 (HPA‐5), are very effective catalysts in the extractive oxidative desulfurization of fuels using molecular oxygen. Our contribution focuses on aspects of catalyst stability and deactivation caused by the accumulation of acidic products and intermediates, i. e. sulfuric acid, formic acid, acetic acid, sulfoacetic acid or 2‐sulfobenzoic acid. These compounds reduce the pH value of the aqueous catalyst phase during the course of the desulfurization reaction. At lower pH values, the higher V‐substituted species rearrange to lower V‐substituted species and VO2+. This rearrangement is responsible for a decreasing activity in extractive oxidative desulfurization. We show that formic acid, acetic acid, sulfoacetic acid and 2‐sulfobenzoic acid block active sites of the catalyst. Oxalic acid, in contrast, has been found to exert a remarkable positive effect on catalyst activity. The feasibility of catalyst recycling and efficient isolation of the decomposition products is demonstrated using four commercially available organic solvent nanofiltration membranes.
Synergistic Supports Beyond Carbon Black for Polymer Electrolyte Fuel Cell Anodes
Authors: Huang Yiyin , Babu Dickson D. , Wu Maoxiang , Wang Yaobing
Published: August 2018

Polymer electrolyte fuel cells (PEFCs) are among the most advanced energy technologies with low operating temperatures, high energy densities, ease of transportation and storage. However, the deficiencies such as low activity and high cost of the electrocatalysts at anodes greatly hinder their commercialization. The commonly used carbon black supports lack the capacity of regulation over the supported noble metals towards efficient electro‐catalytic oxidation of fuels. In this Mini‐Review, the prerequisite factors in advanced supports are outlined, ranging from self‐supported precious metal alloys as well as non‐noble metal materials, while simultaneously revealing the superiorities of some advanced supports beyond carbon black in terms of electronic conductivity, synergy with surface precious metals, chemical and electrochemical stability, and other possible interactions. The effects arisen from microscopic morphology, nano‐structure, and composition on the electrocatalytic activity/stability are also discussed. Finally, several of the most promising supports are highlighted, and the research trends of synergistic supports in future PEFCs are predicted.
Catalytic Enantioselective Carbonyl Propargylation Beyond Preformed Carbanions: Reductive Coupling and Hydrogen Auto‐Transfer
Authors: Ambler Brett R. , Woo Sang Kook , Krische Michael J.
Published: August 2018

Chiral metal complexes catalyze enantioselective carbonyl propargylation via reductive coupling or as hydrogen auto‐transfer processes, in which reactant alcohols serve dually as reductant and carbonyl proelectrophile. Unlike classical propargylation protocols, which rely on allenylmetal reagents or metallic reductants (e. g. NHK reactions), reductive protocols for carbonyl propargylation can occur in the absence of stoichiometric metals, precluding generation of metallic byproducts. Propargylations of this type exploit both enyne and propargyl halide pronucleophiles.