bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silyl‐Phosphino‐Carbene Complexes of Uranium(IV)
Authors: Lu Erli , Boronski Josef T. , Gregson Matthew , Wooles Ashley J. , Liddle Stephen T. 
Published: March 2018

AbstractUnprecedented silyl‐phosphino‐carbene complexes of uranium(IV) are presented, where before all covalent actinide–carbon double bonds were stabilised by phosphorus(V) substituents or restricted to matrix isolation experiments. Conversion of [U(BIPMTMS)(Cl)(μ‐Cl)2Li(THF)2] (1, BIPMTMS=C(PPh2NSiMe3)2) into [U(BIPMTMS)(Cl){CH(Ph)(SiMe3)}] (2), and addition of [Li{CH(SiMe3)(PPh2)}(THF)]/Me2NCH2CH2NMe2 (TMEDA) gave [U{C(SiMe3)(PPh2)}(BIPMTMS)(μ‐Cl)Li(TMEDA)(μ‐TMEDA)0.5]2 (3) by α‐hydrogen abstraction. Addition of 2,2,2‐cryptand or two equivalents of 4‐N,N‐dimethylaminopyridine (DMAP) to 3 gave [U{C(SiMe3)(PPh2)}(BIPMTMS)(Cl)][Li(2,2,2‐cryptand)] (4) or [U{C(SiMe3)(PPh2)}(BIPMTMS)(DMAP)2] (5). The characterisation data for 3–5 suggest that whilst there is evidence for 3‐centre P−C−U π‐bonding character, the U=C double bond component is dominant in each case. These U=C bonds are the closest to a true uranium alkylidene yet outside of matrix isolation experiments.
Photo‐biocatalytic One‐Pot Cascades for the Enantioselective Synthesis of 1,3‐Mercaptoalkanol Volatile Sulfur Compounds
Authors: Lauder Kate , Toscani Anita , Qi Yuyin , Lim Jesmine , Charnock Simon J. , Korah Krupa , Castagnolo Daniele 
Published: March 2018

AbstractThe synthesis of enantiomerically pure 1,3‐mercaptoalkanol volatile sulfur compounds through a one‐pot photo‐biocatalytic cascade reaction is described. Two new KRED biocatalysts with opposite enantioselectivity were discovered and proved to be efficient on a wide range of substrates. The one‐pot cascade reaction combining photocatalytic thio‐Michael addition with biocatalytic ketoreduction in an aqueous medium provides a green and sustainable approach to enantiomerically pure 1,3‐mercaptoalkanols in high yields with excellent enantioselectivity.
Elektrochemische Oxidation von Lithiumcarbonat generiert Singulett‐Sauerstoff
Authors: Mahne Nika , Renfrew Sara E. , McCloskey Bryan D. , Freunberger Stefan A. 
Published: March 2018

AbstractFeste Alkalicarbonate sind universelle Bestandteile von Passivierungsschichten an Materialien für Interkalationsbatterien, übliche Nebenprodukte in Metall‐O2‐Batterien, und es wird angenommen, dass sie sich reversibel in Metall‐O2 /CO2‐Zellen bilden und zersetzen. In all diesen Kathoden zersetzt sich Li2CO3 zu CO2, sobald es Spannungen >3.8 V vs. Li/Li+ ausgesetzt wird. Beachtenswert ist, dass keine O2‐Entwicklung detektiert wird, wie gemäß der Zersetzungsreaktion 2 Li2CO3 → 4 Li+ + 4 e− + 2 CO2 + O2 zu erwarten wäre. Deswegen war der Verbleib eines der O‐Atome ungeklärt und wurde nicht identifizierten parasitären Reaktionen zugerechnet. Hier zeigen wir, dass hochreaktiver Singulett‐Sauerstoff (1O2) bei der Oxidation von Li2CO3 in einem aprotischen Elektrolyten gebildet und daher nicht als O2 freigesetzt wird. Diese Ergebnisse haben weitreichende Auswirkungen auf die langfristige Zyklisierbarkeit von Batterien: sie untermauern die Wichtigkeit, 1O2 in Metall‐O2‐Batterien zu verhindern, stellen die Möglichkeit einer reversiblen Metall‐O2 /CO2‐Batterie basierend auf einem Carbonat‐Entladeprodukt in Frage und helfen, Grenzflächenreaktivität von Übergangsmetallkathoden mit Li2CO3‐Resten zu erklären.
The Interaction of Guest Molecules with Co‐MOF‐74: A Vis/NIR and Raman Approach
Authors: Strauss Ina , Mundstock Alexander , Hinrichs Dominik , Himstedt Rasmus , Knebel Alexander , Reinhardt Carsten , Dorfs Dirk , Caro Jürgen 
Published: March 2018

AbstractCo‐MOF‐74 rod like crystals with a length of several hundred micrometers are synthesized by a solvothermal procedure and their interaction with different gases is evaluated for selective gas sensing. We show strongly anisotropic absorption behavior of the Co‐MOF‐74 crystals when illuminated with polarized light. The interactions of guests (CO2, propane, propene, Ar, MeOH, H2O) with Co‐MOF‐74, is studied by various spectroscopic techniques. Vis/NIR shows peak shifts of Co‐MOF‐74 depending on the interaction with the guest. In the visible and the NIR the maximum absorbance is shifted selectively corresponding to the intensity of the CoII–guest interaction. Even propene and propane could be distinguished at room temperature by their different interactions with Co‐MOF‐74. Raman spectroscopy was used to detect a modified vibrational behavior of Co‐MOF‐74 upon gas adsorption. We show that the adsorption of H2O leads to a characteristic shift of the peak maxima in the Raman spectra.
Electrochemical Oxidation of Lithium Carbonate Generates Singlet Oxygen
Authors: Mahne Nika , Renfrew Sara E. , McCloskey Bryan D. , Freunberger Stefan A. 
Published: March 2018

AbstractSolid alkali metal carbonates are universal passivation layer components of intercalation battery materials and common side products in metal‐O2 batteries, and are believed to form and decompose reversibly in metal‐O2/CO2 cells. In these cathodes, Li2CO3 decomposes to CO2 when exposed to potentials above 3.8 V vs. Li/Li+. However, O2 evolution, as would be expected according to the decomposition reaction 2 Li2CO3→4 Li++4 e−+2 CO2+O2, is not detected. O atoms are thus unaccounted for, which was previously ascribed to unidentified parasitic reactions. Here, we show that highly reactive singlet oxygen (1O2) forms upon oxidizing Li2CO3 in an aprotic electrolyte and therefore does not evolve as O2. These results have substantial implications for the long‐term cyclability of batteries: they underpin the importance of avoiding 1O2 in metal‐O2 batteries, question the possibility of a reversible metal‐O2/CO2 battery based on a carbonate discharge product, and help explain the interfacial reactivity of transition‐metal cathodes with residual Li2CO3.
Dissolvable layered double hydroxide nanoadsorbent‐based dispersive solid‐phase extraction for highly efficient and eco‐friendly simultaneous microextraction of two toxic metal cations and two anionic azo dyes in real samples
Authors: Arghavani‐Beydokhti Somayeh , Rajabi Maryam , Asghari Alireza 
Published: March 2018

For the first time, a new mode of dispersive solid‐phase extraction is presented as a simple, rapid, adsorbent‐free and environmentally friendly method for the simultaneous microextraction and preconcentration of trace amounts of two metal ions (Pb2+ and Cr3+) and two anionic azo dyes (reactive yellow 15 (RY15) and reactive black 5 (RB5)). This method is based upon the in situ formation of a layered double hydroxide (LDH) nanosorbent through an electrostatic induction process. In this method, extraction of the analytes is performed simultaneously with the formation of the nanosorbent only by adding hydroxide ions. After extraction and separation of the sorbent from the sample solution through a syringe nanofilter, the analytes are eluted by dissolving the LDHs in an acidic solution. Finally, the extracted metal cations and anionic azo dyes are directly determined by micro‐sampling flame atomic absorption spectrometry and micro‐volume UV–visible spectrophotometry, respectively. Under the optimal experimental conditions including 20 μmol of hydroxide ions, 248.4:20.8 μg l−1 of M2+:M3+ ions, 12 cycles of air agitation and 200 μl of CF3COOH (2 M), good linearities were obtained for Pb2+, Cr3+, RY15 and RB5 in the concentration ranges 50–600, 5.0–280, 30–2500 and 30–2000 ng ml−1, respectively, with correlation of determinations higher than 0.995. The preconcentration factor for the target analytes was 50 in a 10 ml sample solution. The limits of detection were found to be 15, 1.5, 10 and 10 μg l−1 for Pb2+, Cr3+, RY15 and RB5, respectively. The intra‐day and inter‐day precisions were in the ranges 4.3–6.1 and 5.5–6.8%, respectively. Additionally, the presented method is applicable for the analysis of the target analytes in different water samples with reasonable recoveries (>87%).
Anchoring H3PW12O40 on aminopropylsilanized spinel‐type cobalt oxide (Co3O4‐SiPrNH2/H3PW12O40): A novel nanohybrid adsorbent for removing cationic organic dye pollutants from aqueous solutions
Authors: Pourzare Kolsoum , Farhadi Saeed , Mansourpanah Yaghoub 
Published: March 2018

In this work, phosphotungstic acid (H3PW12O40; PW12) was chemically anchored on aminopropylsiloxane functionalized spherical Co3O4 nanoparticles (Co3O4–SiPrNH2) and the resultant nanocomposite (Co3O4–SiPrNH2/PW12) was fully characterized. The results demonstrated successful anchoring of PW12 on the surface of Co3O4–SiPrNH2nanoparticles. The Co3O4–SiPrNH2/PW12 nanohybrid indicated a specific surface area of 42.14 m2 g−1, which was greater than that of pure PW12 (ca. 5 m2 g−1). The adsorption efficiency of this novel adsorbent nanomaterial was evaluated for removing methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) dyes from aqueous solutions. The hybrid nanomaterial exhibited a high adsorption rate and selective adsorptivity for the cationic MB and RhB dyes compared to those for anionic MO dye. The prepared hybrid nanomaterial removed over 98% of MB within 12 min. The effects of initial pH, contact time, adsorbent dosage, and temperature were investigated on the adsorption process. The adsorption capacity of nanohybrid for cationic MB dye was 38.46 mg g‐1. Also, adsorption kinetics indicated that the adsorption by Co3O4–SiPrNH2/PW12 was well‐modeled using pseudo‐second‐order kinetic model. Finally, thermodynamic parameters revealed that the adsorption was endothermic and spontaneous. The adsorption rate and ability of the Co3O4–SiPrNH2/PW12 were enhanced as compared with Co3O4 and Co3O4–SiPrNH2 samples due to enhanced electrostatic attraction intraction. The nanohybride was easily separated and reused without any change in structure. Thus, it could be a promising green adsorbent for removing organic pollutants in water.
Polypropylene separator coated with a thin layer of poly(lithium acrylate‐co‐butyl acrylate) for high‐performance lithium‐ion batteries
Authors: Zhang Yin , Song You‐Zhi , Yuan Jia‐Jia , Yin Xue , Sun Chuang‐Chao , Zhu Bao‐Ku 
Published: March 2018

ABSTRACTIn this paper, poly(lithium acrylate‐co‐butyl acrylate) [P(AALi‐co‐BA)] was synthesized, and a P(AALi‐co‐BA)‐coated polypropylene (PP) separator was prepared by a simple dip‐coating process. In contrast to the conventional thick, dense gel polymer coating layer, a thin P(AALi‐co‐BA) layer was formed on the PP separator, which had less influence on the pore structure of the original PP separator and was beneficial for the migration of lithium ions through the separator. Furthermore, the AALi units in the copolymer could improve the wettability of the separator, while the BA units provided the separator with strong adhesion to the electrodes. As expected, the modified separators showed good wettability, high ionic conductivity, and excellent interface stability. In addition, the cycle stability and rate performance were also improved significantly. This facile, affordable, and effective method has great application potential for the modification of polyolefin‐based separators. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46423.
Influence of different compatibilizers on the morphology and properties of PA6/PET/glass fiber composites
Authors: Li Shuzhe , Wang Wei , Yu Li , Xia Zhean , Li Xinxin 
Published: March 2018

ABSTRACTThree kinds of compatibilizers, ethylene–ethyl acrylate copolymer (EEA), ethylene–ethyl acrylate–glycidyl methacrylate copolymer (EAG), and ethene–maleic anhydride–glycidyl methacrylate copolymer (EMG), were introduced to PA6/PET/GF blends for the first time to study the effect of different compatibilizers on composite. EEA, EAG, and EMG showed different effect on the properties of PA6/PET/GF blends. An observation of the GF–resin interface by scanning electronic microscope indicated EAG and EMG enhanced the adhesion of resin to GF, while EEA exhibited no improvement. Differential scanning calorimetry analysis showed that both EMG and EAG increased the degree of crystallinity of the PA6/PET/GF blends, whereas EEA declined. According to dynamic mechanical analysis, EAG, and EMG remarkably increased the storage modulus of composites. For the composites at a given GF content of 30 wt %, EMG increased the tensile strength from 140.6 to 156.3 MPa. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46429.
[C6H14N]PbBr3: An ABX3‐Type Semiconducting Perovskite Hybrid with Above‐Room‐Temperature Phase Transition
Authors: Zhang Jing , Liu Xitao , Li Xianfeng , Han Shiguo , Tao Kewen , Wang Yuyin , Ji Chengmin , Sun Zhihua , Luo Junhua 
Published: March 2018

AbstractOrganic–inorganic hybrid perovskites, with the formula ABX3 (A=organic cation, B=metal cation, and X=halide; for example, CH3NH3PbI3), have diverse and intriguing physical properties, such as semiconduction, phase transitions, and optical properties. Herein, a new ABX3‐type semiconducting perovskite‐like hybrid, (hexamethyleneimine)PbBr3 (1), consisting of one‐dimensional inorganic frameworks and cyclic organic cations, is reported. Notably, the inorganic moiety of 1 adopts a perovskite‐like architecture and forms infinite columns composed of face‐sharing PbBr6 octahedra. Strikingly, the organic cation exhibits a highly flexible molecular configuration, which triggers an above‐room‐temperature phase transition, at Tc=338.8 K; this is confirmed by differential scanning calorimetry (DSC), specific heat capacity (Cp), and dielectric measurements. Further structural analysis reveals that the phase transition originates from the molecular configurational distortion of the organic cations coupled with small‐angle reorientation of the PbBr6 octahedra inside the inorganic components. Moreover, temperature‐dependent conductivity and UV/Vis absorption measurements reveal that 1 also displays semiconducting behavior below Tc. It is believed that this work will pave a potential way to design multifeatured perovskite hybrids by utilizing cyclic organic amines.
Organic‐Free, ZnO‐Assisted Synthesis of Zeolite FAU with Tunable SiO2/Al2O3 Molar Ratio
Authors: Guo Ya , Sun Tianjun , Gu Yiming , Liu Xiaowei , Ke Quanli , Wang Shudong 
Published: March 2018

AbstractZeolite FAU with tunable SiO2/Al2O3 molar ratio has been successfully synthesized in the absence of organic structure‐directing agents (OSDA). Specifically, the addition of zinc species contributes to the feasible and effective adjustment of the framework SiO2/Al2O3 molar ratio between about 4 and 6 depending on the amount of zinc species added in the batch composition. In contrast, a typical OSDA such as tetramethylammonium hydroxide (TMAOH) has a limited effect on the SiO2/Al2O3 molar ratio of the zeolite. The role of zinc species is essential for the crystallization of zeolite FAU with a higher SiO2/Al2O3 molar ratio under the particular synthesis conditions. It is speculated that zinc species may suppress the incorporation of aluminum into the aluminosilicate framework, which is due to the Coulombic repulsive interaction. A higher SiO2/Al2O3 molar ratio is also found to be accompanied by a lower CO2 adsorption heat for CO2/CH4 separation.
Countries with an immediate potential for primary prevention of spina bifida and anencephaly: Mandatory fortification of wheat flour with folic acid
Authors: Kancherla Vijaya 
Published: March 2018

ObjectivesMandatory fortification of flour with folic acid has been proven to be a highly effective way to prevent spina bifida and anencephaly. Yet, over 100 countries worldwide do not implement this intervention. Our objectives were to identify countries with an immediate potential for mandatory fortification of wheat flour with folic acid and to estimate the number of preventable cases of spina bifida and anencephaly that would be averted each year through the intervention.MethodsWe examined folic acid fortification characteristics in countries as of September 2017. Country selection criteria included current fortification status, existing industrial capacity for flour production, fortification coverage, and daily grams of per capita wheat flour available for human consumption. We estimated the country‐specific number of preventable cases of spina bifida and anencephaly by calculating the difference between the observed prevalence (prefortification) and expected prevalence that can be achieved postfortification (0.5 per 1,000 live births).ResultsWe identified 71 countries with an immediate potential for mandatory fortification of 145 million metric tons of wheat flour with folic acid. Fortification in identified countries would avert approximately 57,000 live births associated with folic acid‐preventable spina bifida and anencephaly annually and increase global prevention from the current rate of 13% to a new rate of 34%.ConclusionsFortification can be achieved immediately in many countries with existing industrial milling infrastructure. Effective fortification interventions can accelerate global primary prevention efforts of folic acid‐preventable spina bifida and anencephaly, especially in developing countries with a high prevalence of neural tube defects and associated morbidity and mortality.
Intergenerational transmission of gender segregation: How parents’ occupational field affects gender differences in field of study choices
Authors: van der Vleuten Maaike , Jaspers Eva , Maas Ineke , van der Lippe Tanja 
Published: March 2018

The study explores how parents’ occupational field affects gender differences in educational fields. On the one hand, the theory of direct transfer predicts that adolescents enter fields similar to those of their parents because of intergenerational transmission of occupation‐specific resources and that adolescents are more likely to draw upon the resources provided by the higher‐status parent. On the other hand, the theory of sex‐role learning predicts that boys and girls are more likely to choose more gender‐stereotypical fields of study because they learn ‘appropriate’ gender‐role behaviour from their parents’ occupational field and that boys are more likely to learn this behaviour from their father and girls from their mother. We use longitudinal data collected from adolescents and their parents in the Netherlands (N = 2,497) and tested our hypotheses using multiple‐group structural equation modelling and multinomial regression analyses. In line with sex‐role learning, results show that especially mothers who are employed in a more feminine occupational field influence their daughters to enter a more feminine field of study (health, biology, agriculture and veterinary) and their sons to enter a more masculine field of study (science and technology). Mothers’ occupational field therefore not only influences girls’ field of study, but also boys’. This study highlights the role of horizontal characteristics when examining which field of study adolescents enter. Contrary to the stratification literature, which primarily focuses on fathers, this study concludes that mothers play a more important role in gender differences in fields of study.
Functional expression of aryl‐alcohol oxidase in Saccharomyces cerevisiae and Pichia pastoris by directed evolution
Authors: Viña‐Gonzalez Javier , Elbl Katarina , Ponte Xavier , Valero Francisco , Alcalde Miguel 
Published: March 2018

AbstractAryl‐alcohol oxidase (AAO) plays a fundamental role in the fungal ligninolytic secretome, acting as a supplier of H2O2. Despite its highly selective mechanism of action, the presence of this flavooxidase in different biotechnological settings has hitherto been hampered by the lack of appropriate heterologous expression systems. We recently described the functional expression of the AAO from Pleurotus eryngii in Saccharomyces cerevisiae by fusing a chimeric signal peptide (preαproK) and applying structure‐guided evolution. Here, we have obtained an AAO secretion variant that is readily expressed in S. cerevisiae and overproduced in Pichia pastoris. First, the functional expression of AAO in S. cerevisiae was enhanced through the in vivo shuffling of a panel of secretion variants, followed by the focused evolution of the preαproK peptide. The outcome of this evolutionary campaign—an expression variant that accumulated 4 mutations in the chimeric signal peptide, plus two mutations in the mature protein‐ showed 350‐fold improved secretion (4.5 mg/L) and was stable. This secretion mutant was cloned into P. pastoris and fermented in a fed‐batch bioreactor to enhance production to 25 mg/L. While both recombinant AAO from S. cerevisiae and P. pastoris were subjected to the same N‐terminal processing and had a similar pH activity profile, they differed in their kinetic parameters and thermostability. The strong glycosylation observed in the evolved AAO from S. cerevisiae underpinned this effect, since when the mutant was produced in the glycosylation‐deficient S. cerevisiae strain Δkre2, its kinetic parameters and thermostability were comparable to its poorly glycosylated P. pastoris recombinant counterpart.
Engineering cellulolytic bacterium Clostridium thermocellum to co‐ferment cellulose‐ and hemicellulose‐derived sugars simultaneously
Authors: Xiong Wei , Reyes Luis H. , Michener William E. , Maness Pin‐Ching , Chou Katherine J. 
Published: March 2018

AbstractCellulose and hemicellulose are the most abundant components in plant biomass. A preferred Consolidated Bioprocessing (CBP) system is one which can directly convert both cellulose and hemicellulose into target products without adding the costly hydrolytic enzyme cocktail. In this work, the thermophilic, cellulolytic, and anaerobic bacterium, Clostridium thermocellum DSM 1313, was engineered to grow on xylose in addition to cellulose. Both xylA (encoding for xylose isomerase) and xylB (encoding for xylulokinase) genes from the thermophilic anaerobic bacterium Thermoanaerobacter ethanolicus were introduced to enable xylose utilization while still retaining its inherent ability to grow on 6‐carbon substrates. Targeted integration of xylAB into C. thermocellum genome realized simultaneous fermentation of xylose with glucose, with cellobiose (glucose dimer), and with cellulose, respectively, without carbon catabolite repression. We also showed that the respective H2 and ethanol production were twice as much when both xylose and cellulose were consumed simultaneously than when consuming cellulose alone. Moreover, the engineered xylose consumer can also utilize xylo‐oligomers (with degree of polymerization of 2–7) in the presence of xylose. Isotopic tracer studies also revealed that the engineered xylose catabolism contributed to the production of ethanol from xylan which is a model hemicellulose in mixed sugar fermentation, demonstrating immense potential of this enhanced CBP strain in co‐utilizing both cellulose and hemicellulose for the production of fuels and chemicals.