F. Pelayo García de Arquer  Oleksandr S. Bushuyev  Phil De Luna  Cao‐Thang Dinh  Ali Seifitokaldani  Makhsud I. Saidaminov  Chih‐Shan Tan  Li Na Quan  Andrew Proppe  Md. Golam Kibria  Shana O. Kelley  David Sinton  Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2018,30(38)

Electrochemical reduction of CO₂ is a compelling route to store renewable electricity in the form of carbon‐based fuels. Efficient electrochemical reduction of CO₂ requires catalysts that combine high activity, high selectivity, and low overpotential. Extensive surface reconstruction of metal catalysts under high productivity operating conditions (high current densities, reducing potentials, and variable pH) renders the realization of tailored catalysts that maximize the exposure of the most favorable facets, the number of active sites, and the oxidation state all the more challenging. Earth‐abundant transition metals such as tin, bismuth, and lead have been proven stable and product‐specific, but exhibit limited partial current densities. Here, a strategy that employs bismuth oxyhalides as a template from which 2D bismuth‐based catalysts are derived is reported. The BiOBr‐templated catalyst exhibits a preferential exposure of highly active Bi () facets. Thereby, the CO₂ reduction reaction selectivity is increased to over 90% Faradaic efficiency and simultaneously stable current densities of up to 200 mA cm^?2 are achieved—more than a twofold increase in the production of the energy‐storage liquid formic acid compared to previous best Bi catalysts.  相似文献   

    

Shiyan Zhang  Spencer J. Kieffer  Chunjie Zhang  Andrew G. Alleyne  Paul V. Braun 《Advanced materials (Deerfield Beach, Fla.)》2018,30(38)

A facile approach to locally concentrate analytes of interest will significantly enhance miniaturized, integrated chemical‐analysis systems. Here, the directed analyte transport and concentration using ≈200 µm‐diameter E‐jet printed chemical potential wells in a polyacrylamide hydrogel is demonstrated. Using a cationic well as the model system, anionic analytes are accumulated into a microscale area with a local concentration enhancement of >50‐fold relative to the surrounding area. By downscaling the diameter of the chemical potential well from a few millimeters to 100s of micrometers, it is found, using both fluorescence and Raman microscopy, that the molecular collection capacity of the well is greatly improved. Additionally, it is shown that molecules can be simultaneously transported and concentrated to arrays of microscale regions using an array of microscale chemical potential wells. This approach enhances many‐fold the limit of detection, enables the formation of microscale potential well arrays with a variety of chemical properties, and provides a novel microscale molecular manipulation technique as an alternative to traditional microfluidic‐based systems.  相似文献   

    

Andrew Sinclair  Mary Beth O'Kelly  Tao Bai  Hsiang‐Chieh Hung  Priyesh Jain  Shaoyi Jiang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(39)

Injectable and malleable hydrogels that combine excellent biocompatibility, physiological stability, and ease of use are highly desirable for biomedical applications. Here, a simple and scalable strategy is reported to make injectable and malleable zwitterionic polycarboxybetaine hydrogels, which are superhydrophilic, nonimmunogenic, and completely devoid of nonspecific interactions. When zwitterionic microgels are reconstructed, the combination of covalent crosslinking inside each microgel and supramolecular interactions between them gives the resulting zwitterionic injectable pellet (ZIP) constructs supportive moduli and tunable viscoelasticity. ZIP constructs can be lyophilized to a sterile powder that fully recovers its strength and elasticity upon rehydration, simplifying storage and formulation. The lyophilized powder can be reconstituted with any aqueous suspension of cells or therapeutics, and rapidly and spontaneously self‐heals into a homogeneous composite construct. This versatile and highly biocompatible platform material shows great promise for many applications, including as an injectable cell culture scaffold that promotes multipotent stem cell expansion and provides oxidative stress protection.  相似文献   

    

Andrew J. Gravelle  Carolin Blach  Jochen Weiss  Shai Barbut  Alejandro G. Marangoni 《European Journal of Lipid Science and Technology》2017,119(11)

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Guomin Han  Michael R Webb  Chandra Richter  Jessica Parsons  Andrew L Waterhouse 《Journal of the science of food and agriculture》2017,97(11):3847-3854

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Andrew M Beacham  Paul Hand  David AC Pink  James M Monaghan 《Journal of the science of food and agriculture》2017,97(15):5271-5277

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Andrew Vincent  Otto I. Savolainen  Partho Sen  Nils‐Gunnar Carlsson  Annette Almgren  Helen Lindqvist  Mads Vendelbo Lind  Ingrid Undeland  Ann‐Sofie Sandberg  Alastair B. Ross 《Molecular nutrition & food research》2017,61(3)

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Paris Grant-Preece  Celia Barril  Leigh M. Schmidtke  Geoffrey R. Scollary  Andrew C. Clark 《Critical reviews in food science and nutrition》2017,57(4):743-754

Bottled white wine may be exposed to UV-visible light for considerable periods of time before it is consumed. Light exposure may induce an off-flavor known as “sunlight” flavor, bleach the color of the wine, and/or increase browning and deplete sulfur dioxide. The changes that occur in bottled white wine exposed to light depend on the wine composition, the irradiation conditions, and the light exposure time. The light-induced changes in the aroma, volatile composition, color, and concentrations of oxygen and sulfur dioxide in bottled white wine are reviewed. In addition, the photochemical reactions thought to have a role in these changes are described. These include the riboflavin-sensitized oxidation of methionine, resulting in the formation of methanethiol and dimethyl disulfide, and the photodegradation of iron(III) tartrate, which gives rise to glyoxylic acid, an aldehyde known to react with flavan-3-ols to form yellow xanthylium cation pigments.  相似文献   

    

Volkan Yesilyurt  Andrew M. Ayoob  Jeffrey T. Borenstein  Robert Langer  Daniel G. Anderson 《Advanced materials (Deerfield Beach, Fla.)》2017,29(19)

Hydrogels play a central role in a number of medical applications and new research aims to engineer their mechanical properties to improve their capacity to mimic the functional dynamics of native tissues. This study shows hierarchical mechanical tuning of hydrogel networks by utilizing mixtures of kinetically distinct reversible covalent crosslinks. A methodology is described to precisely tune stress relaxation in PEG networks formed from mixtures of two different phenylboronic acid derivatives with unique diol complexation rates, 4‐carboxyphenylboronic acid, and o‐aminomethylphenylboronic acid. Gel relaxation time and the mechanical response to dynamic shear are exquisitely controlled by the relative concentrations of the phenylboronic acid derivatives. The differences observed in the crossover frequencies corresponding to pK_a differences in the phenylboronic acid derivatives directly connect the molecular kinetics of the reversible crosslinks to the macroscopic dynamic mechanical behavior. Mechanical tuning by mixing reversible covalent crosslinking kinetics is found to be independent of other attributes of network architecture, such as molecular weight between crosslinks.  相似文献   

    

Shengfu Yang  Cheng Feng  Daniel Spence  Aula M. A. A. Al Hindawi  Elspeth Latimer  Andrew M. Ellis  Chris Binns  Davide Peddis  Sarnjeet S. Dhesi  Liying Zhang  Yafei Zhang  Kalliopi N. Trohidou  Marianna Vasilakaki  Nikolaos Ntallis  Ian MacLaren  Frank M. F. de Groot 《Advanced materials (Deerfield Beach, Fla.)》2017,29(1)

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