bluuebunny/crossref_metadata_2025 huggingface dataset:
Strain Coupling of Conversion‐type Fe3O4 Thin Films for Lithium Ion Batteries
Authors: Hwang Sooyeon , Meng Qingping , Chen Ping‐Fan , Kisslinger Kim , Cen Jiajie , Orlov Alexander , Zhu Yimei , Stach Eric A. , Chu Ying‐Hao , Su Dong
Published: May 2017

Lithiation/delithiation induces significant stresses and strains into the electrodes for lithium ion batteries, which can severely degrade their cycling performance. Moreover, this electrochemically induced strain can interact with the local strain existing at solid–solid interfaces. It is not clear how this interaction affects the lithiation mechanism. The effect of this coupling on the lithiation kinetics in epitaxial Fe3O4 thin film on a Nb‐doped SrTiO3 substrate is investigated. In situ and ex situ transmission electron microscopy (TEM) results show that the lithiation is suppressed by the compressive interfacial strain. At the interface between the film and substrate, the existence of LixFe3O4 rock‐salt phase during lithiation consequently restrains the film from delamination. 2D phase‐field simulation verifies the effect of strain. This work provides critical insights of understanding the solid–solid interfaces of conversion‐type electrodes.
Light‐Induced Bidirectional Metal‐to‐Metal Charge Transfer in a Linear Fe2Co Complex
Authors: Hu Ji‐Xiang , Luo Lun , Lv Xiao‐Jin , Liu Lei , Liu Qiang , Yang Yi‐Kai , Duan Chun‐Ying , Luo Yi , Liu Tao
Published: May 2017

It is a challenge to reversibly switch both magnetism and polarity using light irradiation. Herein we report a linear Fe2Co complex, whereby interconversion between FeIIILS(μ‐CN)CoIIHS(μ‐NC)FeIIILS (LS=low‐spin, HS=high‐spin) and FeIIILS(μ‐CN)CoIIILS(μ‐NC)FeIILS linkages could be achieved upon heating and cooling, or alternating laser irradiation at 808 and 532 nm. The electron spin arrangement and charge distribution were simultaneously tuned accompanying bidirectional metal‐to‐metal charge transfer, providing switchable polarity and magnetism in the complex.
Porphyrin Bound to i‐Motifs: Intercalation versus External Groove Binding
Authors: Qin Tingxiao , Liu Kunhui , Song Di , Yang Chunfan , Su Hongmei
Published: May 2017

G‐rich and C‐rich DNA can fold into the tetrastranded helical structures G quadruplex or C quadruplex (i‐motif), which are considered to be specific drug targets for cancer therapy. A large number of small molecules (so‐called ligands), which can bind and modulate the stability of G quadruplex structures, have been widely examined. Much less is known, however, about the ligand binding interactions with the C quadruplex (i‐motif). By combining steady‐state measurements (UV/Vis, fluorescence, and induced circular dichroism (ICD)) with time‐resolved laser flash photolysis spectroscopy, we have studied the binding interactions of cationic porphyrin (5,10,15,20‐tetrakis(N‐methylpyridinium‐4‐yl)‐21 H,23 H‐porphyrin, abbreviated as TMPyP4) with i‐motifs (C3TA2)3C3T and (C4A4C4)2. The intercalation binding mode through π–π stacking of the porphyrin macrocycle and the C:C+ hemiprotonated base pair has been identified for the first time. The coexistent binding modes of intercalation (≈80 %) versus external major‐groove binding (≈20 %) have been determined quantitatively, thereby allowing a fuller understanding of the porphyrin–i‐motif interactions. The ionic strength was found to play an important role in affecting affects the binding modes, with the progressive increase in the ionic strength resulting in the gradual decrease in the intercalation percentage and an increase in the groove‐binding percentage. Furthermore, an extended study of the porphyrin derivative with four bulky side‐arm substituents (T4) suggests a complete prohibition of the intercalation mode owing to large steric hindrance, thereby providing a novel groove‐binding ligand with site selectivity. These results provide in‐depth mechanistic insights to better understand the ligand interactions with i‐motifs and guidance for related applications in anticancer drug design.
Methanol as carbon substrate in the bio‐economy: Metabolic engineering of aerobic methylotrophic bacteria for production of value‐added chemicals
Authors: Pfeifenschneider Johannes , Brautaset Trygve , Wendisch Volker F.
Published: May 2017

Bacteria are widely used as cell factories for production of enzymes and chemicals, mostly from sugars. Methylotrophic bacteria can utilize the one‐carbon compound methanol as sole carbon source for growth, and metabolic engineering is being used to develop bioprocesses based on these organisms for conversion of methanol into value‐added chemicals. Methylotrophic model strains include both Gram‐positive and Gram‐negative bacteria and in all cases methanol metabolism proceeds via the cell‐toxic intermediate formaldehyde. Thus, understanding the genetics, biochemistry, and regulation of methylotrophic pathways is crucial for successful strain development and for their concomitant fermentations. Also, such basic knowledge has proven useful for design of strategies and approaches for the rational transfer of methylotrophy into non‐methylotrophic bacteria. In the current review we highlight the best studied methylotrophic model organisms, with particular focus on the Gram‐positive Bacillus methanolicus and the Gram‐negative Methylobacterium extorquens, including their genetics and physiology. We present successful metabolic engineering examples leading to the construction of recombinant strains for the production of amino acids, platform chemicals, terpenoids and dicarboxylic acids derivatives from methanol as sole carbon source. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd
Advances in the use of genetically modified plant biomass for biodiesel generation
Authors: Wan Shen , Truong‐Trieu Victoria MT , Ward Tonya , Whalen Joann K. , Altosaar Illimar
Published: May 2017

Biodiesel is a low‐carbon‐intensity renewable fuel with up to 99% lower greenhouse gas emissions than petroleum‐based diesel. The use of oil crops for biodiesel is under critical examination. It is expensive and suffers from the food versus fuel risk/benefit problem. Consequently, many countries (e.g. Malaysia and countries in the EU) are scaling back the use of oil crops as feedstock for biofuel production. The limitations of these traditional crops are leading the renewable fuels industry to consider innovative, sustainable, and profitable biomass‐based platforms. Plant genetic engineering and other new breeding technologies are essential for developing such biomass‐based platforms because they enhance plant tolerance to abiotic and biotic stresses, resulting in higher feedstock yields, greater net energy gain, and the generation of high‐value co‐products. We review and summarize the recent improvements of oil crops through plant genetic engineering that may increase widespread and cost‐effective production of biodiesel and value‐added co‐products for green chemistry applications. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd
Das Nieuwe Provinciehuis in Antwerpen
Authors: Jansen Wim , De Rycke Klaas , Eppenschwandtner Martin , Eisenbach Philipp
Published: May 2017

Erst in der autonomen Region Flandern, später im ganzen Land, besteht in Belgien seit der Einführung des „Bouwmeesters” (1995) ein hoher Anspruch an eine neue Architekturkultur. Der Baumeister kümmert sich um die architektonische Qualität von öffentlichen und halböffentlichen Bauprojekten. Sein wichtigstes Instrument ist dabei das Open‐Call‐System, welches bei einer entsprechenden Ausschreibung zunächst die architektonische Haltung eines Büros abfragt. Erst nach Auswahl eines Büros muss dieses einen konkreten Vorschlag ausarbeiten. Das eröffnet auch jungen Architekturbüros Chancen, mit wenig Aufwand ihr Können zu beweisen. Das Provinciehuis in Antwerpen ist auf diese Weise aus einem „open oproep”‐Wettbewerb hervorgegangen. Kennzeichnend für dieses 58 m hohe Gebäude ist seine leichte Verdrehung. Ausgeführt in Ortbetonbauweise in Sichtbeton, dürfte der Neubau für belgische Verhältnisse als ungewöhnlich gelten, werden doch die meisten Hochhäuser in Belgien üblicherweise in Fertigbetonbauweise erstellt.
Phosphorescent Iridium(III) Cyclometalates Supported by 2‐(1,2‐Dihydronaphthalen‐4‐yl)pyridine Ligand
Authors: Park Jae Young , Lee Min Hyung
Published: May 2017

Novel Ir(III) cyclometalates, (dnpy)
2Ir(acac) (2) and fac‐Ir(dnpy)3 (3), supported by 2‐(1,2‐dihydronaphthalen‐4‐yl)pyridyl ligand (dnpy) were synthesized and characterized. X‐ray diffraction study on 3 revealed facial arrangement of three dnpy ligands around the Ir center. Photoluminescence (PL) spectra of 2 exhibited orange emission centered at 590 nm, which is almost similar to that observed for 2‐naphthylpyridine complex, (napy)
2Ir(acac) (
III
). In contrast, compound 3 displayed blue‐shifted, yellow emission at 550 nm. Tris‐complex 3 showed higher quantum efficiencies than 2 in both the solution and film states. Cyclic voltammetry measurements indicated that replacing naphthyl with 1,2‐dihydronaphthyl ring raises both the metal‐centered HOMO level and ligand‐centered LUMO level in 2 and 3. It was suggested that 1,2‐dihydronaphthyl ring has a stronger electron‐donating effect than naphthyl ring, while the π* orbital of dnpy ligand is less stabilized due to partial conjugation of the dihydronaphthyl ring.
Childhood trauma and negative memory bias as shared risk factors for psychopathology and comorbidity in a naturalistic psychiatric patient sample
Authors: Vrijsen Janna N. , van Amen Camiel T. , Koekkoek Bauke , van Oostrom Iris , Schene Aart H. , Tendolkar Indira
Published: May 2017

Background

Both childhood trauma and negative memory bias are associated with the onset and severity level of several psychiatric disorders, such as depression and anxiety disorders. Studies on these risk factors, however, generally use homogeneous noncomorbid samples. Hence, studies in naturalistic psychiatric samples are lacking. Moreover, we know little about the quantitative relationship between the frequency of traumatic childhood events, strength of memory bias and number of comorbid psychiatric disorders; the latter being an index of severity. The current study examined the association of childhood trauma and negative memory bias with psychopathology in a large naturalistic psychiatric patient sample.

Methods

Frequency of traumatic childhood events (emotional neglect, psychological‐, physical‐ and sexual abuse) was assessed using a questionnaire in a sample of 252 adult psychiatric patients with no psychotic or bipolar‐I disorder and no cognitive disorder as main diagnosis. Patients were diagnosed for DSM‐IV Axis‐I and Axis‐II disorders using a structured clinical interview. This allowed for the assessment of comorbidity between disorders. Negative memory bias for verbal stimuli was measured using a computer task.

Results

Linear regression models revealed that the frequency of childhood trauma as well as negative memory bias was positively associated with psychiatric comorbidity, separately and above and beyond each other (all p < .01).

Conclusions

The results indicate that childhood trauma and negative memory bias may be of importance for a broader spectrum of psychiatric diagnoses, besides the frequently studied affective disorders. Importantly, frequently experiencing traumatic events during childhood increases the risk of comorbid psychiatric disorders.
The innovative development in interferon beta treatments of relapsing‐remitting multiple sclerosis
Authors: Madsen Claus
Published: May 2017

The introduction of interferon beta therapies more than 20 years ago marked a milestone in the treatment of relapsing‐remitting multiple sclerosis (RRMS) with a significant impact on the approach to modern multiple sclerosis (MS) care. Key learnings and perspectives from the early days of disease modifying therapies in MS have improved the knowledge base of MS, need for treatment, and patient care. The continuous development of interferons over the past two decades outlines a journey with increased understanding of the pharmacodynamics and pharmacokinetic mechanisms of interferons, leading to innovative formulations with an improved benefit/risk profile.
YY1 directly suppresses MYCT1 leading to laryngeal tumorigenesis and progress
Authors: Qu Si‐Yao , Sun Yuan‐Yuan , Li Yun‐Hui , Xu Zhen‐Ming , Fu Wei‐Neng
Published: May 2017

YY1 is a key transcription factor and plays different roles in various cancers. However, role and mechanism of YY1 in laryngeal cancer are still unknown. YY1 and MYCT1 mRNA and protein levels were detected by Real‐time RT‐PCR and Western Blot methods, respectively. Binding of YY1 to MYCT1 promoter was predicted and confirmed by bioinformatics and chromatin immunoprecipitation assays, respectively. MYCT1 promoter activity was assessed by dual luciferase assay system. Laryngeal cancer cell proliferation, migration, and apoptosis were evaluated by cell viability, colony formation, cell scratch assay, transwell assay, and flow cytometry methods, respectively. YY1 and MYCT1 were upregulated and downregulated at transcriptional level in laryngeal cancer, respectively, which showed a negative correlation between YY1 and MYCT1 expression in laryngeal cancer. Significantly higher expression of YY1 and lower expression of MYCT1 were found in laryngeal cancer tissues of patients with lymphatic metastasis than those without metastasis.YY1 directly bound to MYCT1 promoter region and inhibited its promoter activity. YY1 silence had similar biological functions as MYCT1 overexpression in repressiveness of proliferation and migration, and promotion of apoptosis in laryngeal cancer cells. However, the effects of YY1 silence were recovered by MYCT1 knockdown. YY1 promotes proliferation and migration with suppression of apoptosis via directly inhibiting MYCT1 in laryngeal cancer cells, suggesting that YY1 is a useful target as a potential oncogene in laryngeal cancer development and progression.
Selective Fe Promotion on Au Nanoparticles: An Efficient Way to Activate Au/SiO2 Catalysts for the CO Oxidation Reaction
Authors: Wu Chunzheng , Bertoni Giovanni , Marras Sergio , Manna Liberato , Colombo Massimo
Published: May 2017

The fabrication of the metal–metal oxide interface for the design and preparation of heterogeneous catalysts has been widely considered. In this work, a simple, aqueous‐phase Fe promotion strategy was studied on an inactive Au/SiO2 model catalyst to generate an active Au–FeOx interface for the CO oxidation. We found that the addition of either Fe2+ or Fe3+ led to significantly higher activity if the Au NPs were already deposited on the SiO2 compared to a prepromotion of the bare support. Combining X‐ray diffraction, elemental analysis, transmission electron microscopy and energy dispersive X‐ray spectroscopy characterizations with the CO oxidation tests, we proved that the postpromotion strategy could more efficiently fabricate the Au‐Fe interface, which after a proper thermal pretreatment could transform to the catalytically active Au–FeOx interface. The formation of such Au–Fe species interface was ascribed to the selective accumulation of the Fe3+ hydrolysis products on the Au nanoparticles (NPs), driven both by a heterogeneous nucleation/growth mechanism and a direct electrostatic adsorption mechanism.
Ruthenium‐Catalyzed C−H Bond Alkylation of Arylphosphine Oxides with Alkenes: A Straightforward Access to Bifunctional Phosphorous Ligands with a Pendent Carboxylate
Authors: Wang Chang‐Sheng , Dixneuf Pierre H. , Soulé Jean‐François
Published: May 2017

An efficient approach for the fast modification of arylphosphine oxides involving ruthenium(II)‐catalyzed C−H bond alkylation with functional alkenes versus alkenylation has been developed depending on the acidic reaction conditions. Using this methodology, a few examples of desymmetrization of diarylphosphine oxides has allowed the formation of phosphorus derivatives containing three different substituents. After reduction of the phosphine oxide, this method allows the formation of aryl phosphines bearing a flexible pendent carboxylate.
Hierarchical Nickel Cobaltate/Manganese Dioxide Core‐Shell Nanowire Arrays on Graphene‐Decorated Nickel Foam for High‐Performance Supercapacitors
Authors: Chen Hao , Hsieh Chien‐Kuo , Yang Yue , Liu Xiao Ying , Lin Che‐Hsien , Tsai Chuen‐Horng , Wen Zhong Quan , Dong Fan , Zhang Yu Xin
Published: May 2017

Hierarchical NiCo2O4@MnO2 core‐shell nanowire arrays have been synthesized on graphene‐nickel foam as binder‐free electrodes. The thickness of MnO2 nanosheets can be controlled by different hydrothermal reaction times, and a whole array of unique NiCo2O4@MnO2 nanostructures have been synthesized and investigated successfully for supercapacitor applications. The graphene deposited on nickel foam can enhance the electrical conductivity of electrode materials and strengthen corrosion resistance of the current collector. As a result, NiCo2O4@MnO2 core‐shell arrays electrode exhibits an ultra‐high specific capacitance of 2125 F g−1 at a current density of 1 A g−1, outstanding cycling stability (93.4 % of its initial value after 5000 cycles) and good rate performance. In addition, an asymmetric supercapacitor based on NiCo2O4@MnO2 as the positive electrode and activated graphene (AG) as the negative electrode achieves an energy density of 27.8 Wh kg−1 at a power density of 400.3 W Kg−1. These notable findings suggest that the unique NiCo2O4@MnO2 core‐shell nanostructure on graphene‐nickel foam is a potential candidate for application as a high‐performance supercapacitor electrode.
Photoelectrochemical Catalysis toward Selective Anaerobic Oxidation of Alcohols
Authors: Zhang Ruikang , Shao Mingfei , Li Zhenhua , Ning Fanyu , Wei Min , Evans David G. , Duan Xue
Published: May 2017

Selective oxidation of alcohols to aldehydes plays an important role in perfumery, pharmaceuticals, and agrochemicals industry. Different from traditional catalysis or photocatalytic process, here we report an effective photoelectrochemical (PEC) approach for selective anaerobic oxidation of alcohols accompanied with H2 production by means of solar energy. By using TiO2 nanowires modified with graphitic carbon layer as photoanode, benzyl alcohol (BA) has been oxidized to benzaldehyde with high efficiency and selectivity (>99 %) in aqueous media at room temperature, superior to individual electrocatalytic or photocatalytic processes. Moreover, this PEC synthesis method can be effectively extended to the oxidation of several other aryl alcohols to their corresponding aldehydes under mild conditions. The electron spin resonance (ESR) results indicate the formation of intermediate active oxygen (O2.−) on the photoanode, which further reacts with alcohols to produce final aldehyde compounds.
Modulation of Bambusuril Anion Affinity in Water
Authors: Havel Vaclav , Babiak Michal , Sindelar Vladimir
Published: May 2017

Neutral and negatively charged anion receptors functioning in pure water are rare in supramolecular chemistry. Moreover, studies on adjusting the affinity of such receptors toward anions in water are absent from the literature. Two new bambusurils, 1 a and 2 a, were prepared to demonstrate that the affinity of bambusurils towards anions can be altered by the length of carboxyalkyl groups attached to the macrocycles. The stability of the bambusuril complexes was further controlled by the pH value. The crystal structure of bambusuril 1 a was described, in which two carboxyalkyl arms fold into the macrocycle cavity, thus forming the intramolecular self‐inclusion complex.
A Specific and Covalent JNK‐1 Ligand Selected from an Encoded Self‐Assembling Chemical Library
Authors: Zimmermann Gunther , Rieder Ulrike , Bajic Davor , Vanetti Sara , Chaikuad Apirat , Knapp Stefan , Scheuermann Jörg , Mattarella Martin , Neri Dario
Published: May 2017

We describe the construction of a DNA‐encoded chemical library comprising 148 135 members, generated through the self‐assembly of two sub‐libraries, containing 265 and 559 members, respectively. The library was designed to contain building blocks potentially capable of forming covalent interactions with target proteins. Selections performed with JNK1, a kinase containing a conserved cysteine residue close to the ATP binding site, revealed the preferential enrichment of a 2‐phenoxynicotinic acid moiety (building block A82) and a 4‐(3,4‐difluorophenyl)‐4‐oxobut‐2‐enoic acid moiety (building block B272). When the two compounds were joined by a short PEG linker, the resulting bidentate binder (A82‐L‐B272) was able to covalently modify JNK1 in the presence of a large molar excess of glutathione (0.5 mm), used to simulate intracellular reducing conditions. By contrast, derivatives of the individual building blocks were not able to covalently modify JNK1 in the same experimental conditions. The A82‐L‐B272 ligand was selective over related kinases (BTK and GAK), which also contain targetable cysteine residues in the vicinity of the active site.
Hydrogen‐Bond Strength of CC and GG Pairs Determined by Steric Repulsion: Electrostatics and Charge Transfer Overruled
Authors: van der Lubbe Stephanie C. C. , Fonseca Guerra Célia
Published: May 2017

Theoretical and experimental studies have elucidated the bonding mechanism in hydrogen bonds as an electrostatic interaction, which also exhibits considerable stabilization by charge transfer, polarization, and dispersion interactions. Therefore, these components have been used to rationalize the differences in strength of hydrogen‐bonded systems. A completely new viewpoint is presented, in which the Pauli (steric) repulsion controls the mechanism of hydrogen bonding. Quantum chemical computations on the mismatched DNA base pairs CC and GG (C=cytosine, G=guanine) show that the enhanced stabilization and shorter distance of GG is determined entirely by the difference in the Pauli repulsion, which is significantly less repulsive for GG than for CC. This is the first time that evidence is presented for the Pauli repulsion as decisive factor in relative hydrogen‐bond strengths and lengths.
N‐Radical‐Initiated Cyclization through Insertion of Sulfur Dioxide under Photoinduced Catalyst‐Free Conditions
Authors: Mao Runyu , Yuan Zheng , Li Yuewen , Wu Jie
Published: May 2017

A N‐radical‐initiated cyclization involving the sulfonylation of unactivated alkenes through insertion of sulfur dioxide in the presence of visible light under catalyst‐free conditions is accomplished. A range of sulfonated 3,4‐dihydro‐2H‐pyrroles can be generated in good yields under photoinduced sulfonylative conditions. Additionally, the corresponding 2‐(3,4‐dihydro‐2H‐pyrrol‐2‐yl)methylsulfonyl‐1‐arylethanones can be easily converted to 3,4‐dihydro‐2H‐1,4‐thiazine 1,1‐dioxides. This photoinduced transformation occurs efficiently at room temperature under catalyst‐free conditions, and various functional groups can be tolerated. A tandem radical process is involved through the iminyl radical‐mediated cyclization with the insertion of sulfur dioxide; this process shows high efficiency and good selectivity.
Catalytic Electrophilic C−H Borylation Using NHC⋅Boranes and Iodine Forms C2‐, not C3‐, Borylated Indoles
Authors: McGough John S. , Cid Jessica , Ingleson Michael J.
Published: May 2017

Activation of N‐heterocyclic carbene boranes (NHC⋅BH3) by I2 enables the metal‐free catalytic C−H borylation of heteroarenes with formation of H2 as the by‐product in a process that uses only bench stable precursors. The borylation of indoles using NHC⋅BH3/I2 produces C2‐borylated indoles exclusively in contrast to other catalytic electrophilic C−H borylation methods. Mechanistic studies indicate that this is due to C3 to C2 boron migration facilitated by the absence of exogenous Brønsted bases. Thus this C−H borylation methodology proceeds under sufficiently Brønsted acidic conditions to enable the thermodynamic C2‐borylated indole isomer to be formed instead of the C3 borylated‐isomer. This demonstrates that electrophilic C−H borylation can be used to access a wider range of borylated regioisomers than reported to date.
Removal of Endocrine Disrupting Chemicals in Water with the Natural Mineral Alginite
Authors: Tröbs Ramona , Bertau Martin
Published: May 2017

Die nachgewiesenen Konzentrationen wie auch die Vielfalt von endokrin wirksamen Chemikalien (EDC) in Oberflächengewässern nehmen seit Jahren zu. Die toxische Wirkung der EDC auf verschiedene Umweltorganismen ist schon seit längerer Zeit bekannt. Gegenwärtige Verfahren zur Entfernung der EDC, wie Ozonierung oder Adsorption an Aktivkohle sind mit hohen Kosten verbunden. Das natürlich vorkommende Gestein Alginit kann die existierende Methodik wirkungsvoll ergänzen. Aufgrund seines heterogenen Aufbaus lassen sich sowohl polare als auch unpolare EDC aus dem Wasser entfernen. Es werden Abreicherungsraten bis zu 100 % erreicht.
Spherical P‐modified catalysts for heterogeneous cross‐aldol condensation of formaldehyde with methyl acetate for methyl acrylate production
Authors: Zuo Cuncun , Li Chunshan , Ge Tingting , Guo Xinpeng , Zhang Suojiang
Published: May 2017

A series of spherical supported catalysts were prepared for the production of methyl acrylate (MA) via cross‐aldol condensation with methyl acetate (MeOAc) and formaldehyde—the simplest aldehyde without α‐H. ZSM‐5, γ‐Al2O3, MCM‐41, SBA‐15, and β‐zeolite were used as supports and phosphorus element (P) was selected for the active component to synthesize the catalyst to study the influence of the catalyst acid‐base properties on the yield of MA. The catalyst was characterized with X‐ray diffraction, XPS, Pyridine FTIR, BET, SEM, TEM, CO2‐TPD, and NH3‐TPD and the changes of the catalyst structure and acid properties were explored. The results showed the carbonyl polarity of methyl acetate was boosted by Lewis acid sites (L acid) and the formaldehyde activation and formation of ester enol form could be promoted by Bronsted acid sites (B acid). Using the fixed‐bed reactor, the effect of calcination temperature, catalyst loading, reaction temperature, molar ratio of reactants, and sources of phosphorus were optimized, then the catalyst life and regeneration performance were also evaluated. Lastly, the catalytic mechanism of P‐modified ZSM‐5 catalysts was proposed.
Dehydration kinetics for coal‐based isobutanol on γ‐Al2O3
Authors: Mi Rongli , Li Yingming , Tian Xueyu , Peng Hailing , Yang Bolun
Published: May 2017

Isobutanol dehydration using γ‐Al2O3 catalysts to produce isobutene was carried out by a fixed bed reactor at 0.1 MPa. The effects of temperature, weight hourly space velocity, and particle size of catalyst on the conversion of isobutanol and selectivity of isobutene were investigated to find the optimum reaction conditions and get the kinetics information. The experimental results indicated that higher temperature could improve the conversion of isobutanol while a peak of selectivity of isobutene can be monitored with the temperature increasing. Meanwhile, increasing the flow rate leads to a decrease in the conversion of isobutanol, but showed little effect on selectivity of isobutene. The intrinsic kinetics model of isobutanol dehydration over γ‐Al2O3 was developed according to the experimental results. The adsorption of isobutanol was considered as a rate‐determining step from the analysis results of reaction mechanism, and kinetics parameters were obtained by Levenberg‐Marquardt algorithm. The calculated results agreed well with the experimental data.
Lead Halide Perovskite Nanocrystals: Stability, Surface Passivation, and Structural Control
Authors: Luo Binbin , Naghadeh Sara Bonabi , Zhang Jin Z.
Published: May 2017

Lead halide (LH) perovskites have received enormous attention recently because of their interesting optoelectronic properties and high power conversion efficiency (PCE) in photovoltaic solar cells. However, material instability toward factors such as water, UV light, temperature, and oxygen have presented a major challenge for practical applications. Recently, LH perovskite nanocrystals (PNCs) have also drawn increasing attention owing to their tunable optical properties and ability to serve as model systems for studying the mechanism of material instability or degradation. Surface passivation of PNCs is critical to achieving high stability and desired optical properties. In this review, we highlight several surface passivation strategies developed for improving the stability of LH perovskites and synthesizing PNCs with different morphologies as a promising class of materials for photovoltaics, light‐emitting diodes (LEDs), and sensing applications.
Towards Characterization of All 3 × 3 Extremal Quasiconvex Quadratic Forms
Authors: Harutyunyan Davit , Milton Graeme Walter
Published: May 2017

Given a d × d quasiconvex quadratic form, d ≥ 3, we prove that if the determinant of its acoustic tensor is an irreducible extremal polynomial that is not identically zero, then the form itself is an extremal quasiconvex quadratic form; i.e., it loses its quasiconvexity whenever a convex quadratic form is subtracted from it. In the special case d=3, we slightly weaken the condition; namely we prove that if the determinant of the acoustic tensor of the quadratic form is an extremal polynomial that is not a perfect square, then the form itself is an extremal quadratic form. In the case d=3 we also prove that if the determinant of the acoustic tensor of the form is identically zero, then the form is either extremal or polyconvex. Also, if the determinant of the acoustic tensor of the form is a perfect square, then the form is either extremal or polycovex, or is a sum of a rank‐1 form and an extremal whose acoustic tensor determinant is identically zero. Here we use the notion of extremality introduced by Milton in 1990. © 2017 Wiley Periodicals, Inc.
Full Correlations across Broad NMR Spectra by Two‐Field Total Correlation Spectroscopy
Authors: Kadeřávek Pavel , Strouk Léonard , Cousin Samuel F. , Charlier Cyril , Bodenhausen Geoffrey , Marquardsen Thorsten , Tyburn Jean‐Max , Bovier Pierre‐Alain , Engelke Frank , Maas Werner , Ferrage Fabien
Published: May 2017

Total correlation spectroscopy (TOCSY) is a key experiment to assign nuclear magnetic resonance (NMR) spectra of complex molecules. Carbon‐13 TOCSY experiments are essential to assign signals of protein side chains. However, the performance of carbon‐13 TOCSY deteriorates at high magnetic fields since the necessarily limited radiofrequency irradiation fails to cover the broad range of carbon‐13 frequencies. Here, we introduce a new concept to overcome the limitations of TOCSY by using two‐field NMR spectroscopy. In two‐field TOCSY experiments, chemical shifts are labelled at high field but isotropic mixing is performed at a much lower magnetic field, where the frequency range of the spectrum is drastically reduced. We obtain complete correlations between all carbon‐13 nuclei belonging to amino acids across the entire spectrum: aromatic, aliphatic and carboxylic. Two‐field TOCSY should be a robust and general approach for the assignment of uniformly carbon‐13 labelled molecules in high‐field and ultra‐high field NMR spectrometers beyond 1000 MHz.
A Simple Strategy for the Controlled Synthesis of Ultrasmall Hexagonal‐Phase NaYF4:Yb,Er Upconversion Nanocrystals
Authors: Zhai Xuesong , Wang Ying , Liu Xiaojuan , Liu Shihu , Lei Pengpeng , Yao Shuang , Song Shuyan , Zhou Liang , Feng Jing , Zhang Hongjie
Published: May 2017

Precise control over the size and crystallographic phase of nanocrystals allows the manipulation of their properties and applications as desired. Hexagonal‐phase NaYF4 (β‐NaYF4) upconversion nanocrystals with efficient luminescence are quite desirable for bio‐applications, but synthetic control over the nanocrystallite size remains challenging. Herein we verify experimentally that control of the hexagonal‐phase nucleation is crucial for controlling the final particle size and the number of hexagonal‐phase seeds strongly depends on the actual F(Na):Y ratio. A negligible number of hexagonal‐phase seeds were formed at low ratio whereas the high ratio yields a very large number of seeds. We also identify that the actual F(Na):Y ratio is more likely related to the different methods employed for the addition of NH4F and NaOH rather than its initial feeding ratio. By taking advantage of this dependence and varying the reaction conditions (temperature and time), β‐NaYF4:Yb,Er nanocrystals with a size smaller than 6 nm can be synthesized. Theoretical modeling shows a good agreement with the experimental results.
Alcoholysis: A Promising Technology for Conversion of Lignocellulose and Platform Chemicals
Authors: Zhu Shanhui , Guo Jing , Wang Xun , Wang Jianguo , Fan Weibin
Published: May 2017

In the catalytic conversion of lignocellulose to valuable products, the first entry point is to break down these biopolymers to sugar units or aromatic monomers, which is conventionally achieved by hydrolysis in water medium. Recent years have seen tremendous progress in the alcoholysis process, which has remarkable advantages, such as the avoidance of treating waste water, suppression of humins or chars, and enhancement of reaction rate and product yield. Advances have been focused on the alcoholysis of cellulose, hemicellulose, and lignin to alkyl glucosides, xylosides, and aromatic monomers, respectively. Alcoholysis of the platform molecule furfuryl alcohol (FAL) to alkyl levulinate (AL) and integrated alcoholysis of cellulose and furfural into AL are also summarized. This Minireview highlights the comparisons between alcoholysis and hydrolysis, the reaction mechanism of alcoholysis, and future challenges for industrial applications.
Priority‐based adaptive access barring for M2M communications in LTE networks using learning automata
Authors: Morvari Faezeh , Ghasemi Abdorasoul
Published: May 2017

Supporting a huge number of machine‐to‐machine devices with different priorities in Long Term Evolution networks is addressed in this paper. We propose a learning automaton (LA)–based scheme for dynamically allocating random access resources to different classes of machine‐to‐machine devices according to their priorities and their demands in each cycle. We then use another LA‐based scheme to adjust the barring factor for each class to control the possible overload. We show that by appropriate updating procedure for these LAs, the system performance asymptotically converges to the optimal performance in which the evolved node B knows the number of access‐attempting devices from each class a priori. Simulation results are provided to show the performance of the proposed scheme in random access resource allocation to defined classes and adjusting the barring factor for each of them.
Importance of long‐term care of diabetic women starting in pregnancy
Authors: Loeken Mary R.
Published: May 2017

Large scale, multi‐center, controlled studies have demonstrated the importance of glycemic control, as indicated by HbA1c levels, in reducing the incidence and progression of diabetic complications. However, Yasue Omori, who began practicing medicine in Tokyo 60 years ago, in 1957, has the vantage point of long‐term continuing care for women with type 2 diabetes, some for several decades. An internist who specializes in diabetic pregnancy, Dr Omori began caring for many of her patients during their pregnancies and continued to care for them following their deliveries, some now more than 50 years. Surprisingly, despite lack of optimal HbA1c levels, they have suffered relatively few diabetic complications. As reported in “The importance of nonstop treatment after delivery for pregnant women with type 2 diabetes” in Diabetes/Metabolism Research and Reviews, Omori and colleagues present a historical perspective that provides evidence that a long‐term patient‐care giver relationship following pregnancy can be valuable in reducing the onset and progression of diabetic complications.
Frequency of invasive plant occurrence is not a suitable proxy for abundance in the Northeast United States
Authors: Cross Tyler , Finn John T. , Bradley Bethany A.
Published: May 2017

Measuring and predicting invasive plant abundance is critical for understanding impacts on ecosystems and economies. Although spatial abundance datasets remain rare, occurrence datasets are increasingly available across broad regional scales. We asked whether the frequency of these point occurrences can be used as a proxy for abundance of invasive plants. We compiled both occurrence and abundance data for 13 regionally important invasive plants in the northeast United States from herbarium records and several contributed distribution datasets. We integrated all available abundance information based on infested area, stem count, percent cover, or qualitative descriptions into abundance rankings ranging from 0 (absent) to 4 (highly abundant). Within equal‐area grid cells of 800 m, we counted numbers of occurrence points and used ordinal regression to test whether higher densities of occurrence points increased the odds of a higher abundance ranking. We compiled a total of 86,854 occurrence points in 34,596 grid cells, of which 26,114 points (30%) within 11,976 cells (35%) had some form of abundance information. Eleven of the 13 species had a slight but significantly positive odds ratio; that is, more occurrence points of a species increased the odds that the species was abundant within the grid cell. However, the predictive ability of the models was poor (κ < 0.2) for the majority of species. Additionally, most grid cells contained only one or two occurrence points, making it impossible to infer abundance in all but a few locations. These results suggest that currently available occurrence datasets do not effectively represent abundance, which could explain why many distribution models based on occurrence data are poor predictors of abundance. Increased efforts to consistently collect and report invasive species abundance, ideally estimating both infested area and average cover, are strongly needed for regional‐scale assessments of potential abundance and associated impact.
A history of diabetes predicts outcomes following myocardial infarction: an analysis of the 28 771 patients in the High‐Risk MI Database
Authors: Tajik Athar A. , Dobre Daniela , Aguilar David , Kjekshus John , Zannad Faiez , Dickstein Kenneth ,   on behalf of the High‐Risk MI Database Scientific Committee
Published: May 2017

Aims

To examine the impact of diabetes mellitus on long‐term clinical outcomes in patients with myocardial infarction (MI) complicated by clinical signs of heart failure (HF) or left ventricular dysfunction (LVD).

Methods and results

The High‐Risk MI Database consists of individual data from 28 771 patients and was created by merging four large recent randomized clinical trials (VALIANT, EPHESUS, OPTIMAAL, and CAPRICORN) that each examined the impact of pharmacological interventions following MI in patients with evidence of HF or LVD. The mean age of patients was 65 years, 70% were male, and almost 94% Caucasian. Overall, 7368 (26%) had a history of diabetes. All the major outcomes were adjudicated by independent end‐point committees. Strong and highly significant associations were found with all major clinical outcomes. Diabetes was associated with an increased risk for all‐cause death [adjusted hazard ratio (HR) 1.37; confidence interval (CI) 1.28–1.46; P < 0.001]. The higher risk for all‐cause death was largely mediated by higher risk for cardiovascular death (adjusted HR 1.38; CI 1.27–1.48; P < 0.001) predominantly due to a substantially increased risk for fatal re‐infarction (adjusted HR 1.78; CI 1.42–2.23; P < 0.001). Additionally, diabetes was associated with an increased risk for hospitalizations, particularly HF hospitalization (adjusted HR 1.50; CI 1.39–1.63; P < 0.001). There were also elevated risks for composite outcomes, particularly death or hospitalization due to HF (adjusted HR 1.48; CI 1.38–1.59; P < 0.001).

Conclusion

The risk for adverse outcomes associated with diabetes remains elevated even after debut of coronary artery disease in patients with MI complicated by clinical signs of HF or LVD. This association is particularly strong for HF‐related outcomes.
Synthesis, Characterization, and Time‐Dependent NMR Spectroscopy Studies of (SP‐4‐2)‐[(trans‐1R,2R/1S,2S‐15N2)‐Cyclohexane‐1,2‐diamine][(13C2)oxalato]platinum(II)
Authors: Höfer Doris , Galanski Mathea Sophia , Keppler Bernhard K.
Published: May 2017

Synthesis and characterization of 15N‐labeled and partially 13C‐labeled oxaliplatin in a racemic mixture with its S,S enantiomer, (SP‐4‐2)‐[(trans‐1R,2R/1S,2S‐15N2)‐cyclohexane‐1,2‐diamine][(13C2)oxalato]platinum(II), is presented. 15N labeling of trans‐cyclohexane‐1,2‐diamine (DACH) was conducted by reacting cyclohexane‐1,2‐dione with the 15N source (15N)hydroxylamine hydrochloride. After reduction, trans‐(15N2)DACH was isolated as a tartrate salt and reacted with K2[PtCl4]. Subsequent reaction with (13C2)oxalate afforded the final 15N‐ and 13C‐labeled oxaliplatin together with its S,S analog. Detailed characterization was performed by one‐ and two‐dimensional 1H, 13C, 15N, and 195Pt NMR spectroscopy; high‐resolution mass spectrometry; and elemental analysis. The reaction behavior towards chloride ions, 5′‐guanosine monophosphate, and l‐methionine was studied by 1D 1H, 13C, and 195Pt NMR spectroscopy and 2D [1H,15N] and [1H,195Pt] NMR spectroscopy.
Synthesis, Physicochemical Characterization, and Cytotoxicity Assessment of CeO2 Nanoparticles with Different Morphologies
Authors: Spezzati Giulia , Fant Kristina , Ahniyaz Anwar , Lundin‐Johnson Maria , Hensen Emiel J. M. , Langermans Harm , Hofmann Jan P.
Published: May 2017

With the growing use of nanomaterials, it is essential to carefully determine whether they represent a risk for potential users. So far, validated stand‐alone methods that allow a proper risk assessment are still rare. In the present study, the cytotoxicity of CeO2 nanoparticles has been assessed. For this purpose, a variety of well‐defined CeO2 nanoparticles has been prepared by using either hydrothermal synthesis or flame spray pyrolysis (FSP), resulting in nanoparticles of different morphologies and sizes. The FSP technique is known to produce particles of a very small size (in the range of nanometers), which can easily become airborne. We employed a characterization procedure that makes use of physicochemical techniques, comprising N2 physisorption, XRD, TEM, as well as ζ‐potential and surface‐charge measurements. The cytotoxicity of the nanoparticles was evaluated in vitro on two different human lung cell lines (A549 and MRC‐5). The tests showed that, despite the differences in surface properties, size, and morphologies, neither of the CeO2 samples gave rise to a cytotoxic response.
Vicinal Diamines as Smart Cosubstrates in the Transaminase‐Catalyzed Asymmetric Amination of Ketones
Authors: Payer Stefan E. , Schrittwieser Joerg H. , Kroutil Wolfgang
Published: May 2017

Transaminases (TAs) have recently been established as catalysts for the asymmetric, reductive amination of prochiral ketones. Depending on the ketone substrate and the amine donor (the cosubstrate), equilibrium constants may limit high conversions; thus, methods to overcome this limitation are required. Removal of the co‐product from the reaction equilibrium through spontaneous, intramolecular reactions has provided a successful solution to this problem; therefore, these amine donors have been named “smart cosubstrates”. Here, we present a comparison of various bifunctional amine donors including vicinal diamines as potential structural cosubstrate motifs. Upon TA‐catalyzed deamination of 1,2‐diamines, spontaneous dimerization of the resulting α‐aminoketones and oxidation gave heteroaromatic pyrazines.
Assessment of a solar‐assisted infrared timber drying system
Authors: Aktaş Mustafa , Ceylan İlhan , Ergün Alper , Gürel Ali Etem , Atar Musa
Published: May 2017

This study investigates convective‐infrared drying characteristics of timber. The biggest disadvantage of infrared heating systems is the uncontrollable rise of the surface temperature up to extremely high values, which causes damage to the product. In this study, the power of an infrared system was controlled and adjusted according to the surface temperature of the product. In doing so, the surface temperature of the infrared heater was prevented from reaching up to values that could damage the product. During the analysis, the surface temperature of the timbers was kept at an average of 65°C, while the bottom temperature was kept at an average of 45°C. The air collector used in the system was found to be 50% efficient. At the end of a 13‐h drying period, the moisture content of pine timbers could be reduced from 1.42 to 0.0948 g water/g dry matter. During the system analysis, parameters such as moisture content, mass diffusion coefficient, and useful energy rate were taken into consideration. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1875–1881, 2017
Dietary intake of selected nutrients and persistence of HPV infection in men
Authors: Lopes Raíssa do Vale C. , Teixeira Juliana A. , Marchioni Dirce , Villa Luisa L. , Giuliano Anna R. , Luiza Baggio Maria , Fisberg Regina M.
Published: May 2017

Human papillomavirus (HPV) infection is a common sexually transmitted disease. Although often transitory, persistent oncogenic HPV infection may progress to a precursor lesion and, if not treated, can further increase the risk of cancer. The purpose of this study was to investigate the relation between dietary intake and HPV persistent infection in men of a Brazilian cohort. The study population consisted of 1,248 men from the Brazilian cohort of the HIM (HPV in Men) Study, ages 18 to 70 years, who completed a quantitative food frequency questionnaire. U Mann‐Whitney test was used to assess differences in median nutrient intake of selected nutrients. The association of dietary intake and persistent HPV infection was assessed in multivariate logistic models. The prevalence of any HPV infection at baseline was 66.6%. Of 1,248 participants analyzed, 1,211 (97.0%) were HPV positive at one or more times during the 4 years of follow‐up and 781 (62.6%) were persistently HPV positive. Men with nonpersistent oncogenic HPV infections had higher median intake of retinol (p = 0.008), vitamin A (p < 0.001) and folate (DFE; p = 0.003) and lower median intake of energy (p = 0.005) and lycopene (p = 0.008) in comparison to men with persistent oncogenic infections. No significant association was found between selected nutrients and persistent oncogenic HPV infection. For nononcogenic persistent infections, only vitamin B12 intake was significantly associated (p = 0.003, test for trend). No association was observed between dietary intake and persistent oncogenic‐type HPV infection; however, vitamin B12 intake was inversely associated with nononcogenic HPV persistence.
Correlation between pre‐pregnancy body mass index and maternal visceral adiposity with fetal biometry during the second trimester
Authors: Lopes Karina R.M. , Souza Alex Sandro R. , Figueiroa José N. , Alves João Guilherme B.
Published: May 2017

Objective

To determine the correlation between pre‐pregnancy body mass index (BMI) and maternal visceral adiposity with fetal biometry during the second trimester.

Methods

A cross‐sectional observational study was conducted among pregnant women who received prenatal care at a center in Recife, Brazil, between October 3, 2011, and September 27, 2013. Pre‐pregnancy BMI was determined at the first prenatal care visit. Maternal visceral adiposity and fetal biometry were measured at the same ultrasonography session. The associations between maternal and fetal variables were evaluated using the Pearson correlation coefficient (R). The Student t test was used to test the null hypothesis of adjusted correlation coefficients.

Results

Overall, 740 women were included. No correlation was found between pre‐pregnancy BMI and any of the fetal biometric variables assessed. By contrast, maternal visceral adiposity positively correlated with fetal abdominal circumference (R=0.529), estimated fetal weight (R=0.524), head circumference (R=0.521), femur length (R=0.521), and biparietal diameter (R=0.524; P<0.001 for all fetal variables). These findings remained statistically significant after controlling for pregnancy length.

Conclusion

Maternal visceral adiposity, but not pre‐pregnancy BMI, positively correlated with fetal biometry during the second trimester.