Gonzalo Murillo  Andreu Blanquer  Carolina Vargas‐Estevez  Lleonard Barrios  Elena Ibáñez  Carme Nogués  Jaume Esteve 《Advanced materials (Deerfield Beach, Fla.)》2017,29(24)

Noninvasive methods for in situ electrical stimulation of human cells open new frontiers to future bioelectronic therapies, where controlled electrical impulses could replace the use of chemical drugs for disease treatment. Here, this study demonstrates that the interaction of living cells with piezoelectric nanogenerators (NGs) induces a local electric field that self‐stimulates and modulates their cell activity, without applying an additional chemical or physical external stimulation. When cells are cultured on top of the NGs, based on 2D ZnO nanosheets, the electromechanical NG–cell interactions stimulate the motility of macrophages and trigger the opening of ion channels present in the plasma membrane of osteoblast‐like cells (Saos‐2) inducing intracellular calcium transients. In addition, excellent cell viability, proliferation, and differentiation are validated. This in situ cell‐scale electrical stimulation of osteoblast‐like cells can be extrapolated to other excitable cells such as neurons or muscle cells, paving the way for future bioelectronic medicines based on cell‐targeted electrical impulses.  相似文献   

    

Li Na Quan  Rafael Quintero‐Bermudez  Oleksandr Voznyy  Grant Walters  Ankit Jain  James Zhangming Fan  Xueli Zheng  Zhenyu Yang  Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2017,29(21)

Perovskite nanocrystals (NCs) have attracted attention due to their high photoluminescence quantum yield (PLQY) in solution; however, maintaining high emission efficiency in the solid state remains a challenge. This study presents a solution‐phase synthesis of efficient green‐emitting perovskite NCs (CsPbBr₃) embedded in robust and air‐stable rhombic prism hexabromide (Cs₄PbBr₆) microcrystals, reaching a PLQY of 90%. Theoretical modeling and experimental characterization suggest that lattice matching between the NCs and the matrix contribute to improved passivation, while spatial confinement enhances the radiative rate of the NCs. In addition, dispersing the NCs in a matrix prevents agglomeration, which explains their high PLQY.  相似文献   

    

Jongmin Choi  Younghoon Kim  Jea Woong Jo  Junghwan Kim  Bin Sun  Grant Walters  F. Pelayo García de Arquer  Rafael Quintero‐Bermudez  Yiying Li  Chih Shan Tan  Li Na Quan  Andrew Pak Tao Kam  Sjoerd Hoogland  Zhenghong Lu  Oleksandr Voznyy  Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2017,29(33)

The tunable bandgap of colloidal quantum dots (CQDs) makes them an attractive material for photovoltaics (PV). The best present‐day CQD PV devices employ zinc oxide (ZnO) as an electron transport layer; however, it is found herein that ZnO's surface defect sites and unfavorable electrical band alignment prevent devices from realizing their full potential. Here, chloride (Cl)‐passivated ZnO generated from a solution of presynthesized ZnO nanoparticles treated using an organic‐solvent‐soluble Cl salt is reported. These new ZnO electrodes exhibit decreased surface trap densities and a favorable electronic band alignment, improving charge extraction from the CQD layer and achieving the best‐cell power conversion efficiency (PCE) of 11.6% and an average PCE of 11.4 ± 0.2%.  相似文献   

    

Ilaria Mariotti  Carolina Pacchi  Stefano Di Vita 《城市工程杂志》2017,24(3):47-66

ABSTRACT

The present paper investigates the location patterns and the effects co-working spaces generate on the urban context, issues that have been neglected by the existing literature. The focus is on Milan, the core of the Italian knowledge-based, creative, digital, and sharing economy, and the city hosting the largest number of co-working spaces in Italy. The paper addresses three main questions: (1) Where are the main locations of co-working spaces in Milan? (2) Are there any transformative effects of co-working spaces, respectively at the urban scale and at the very local scale? (3) What are their impacts in terms of spatial transformation and in terms of innovation in practices (for instance, work, leisure, or culture)? Desk research showed that location patterns of co-working spaces resemble those of service industries in urban areas, with a propinquity to the so-called “creative clusters.” Field research shed light on urban effects, such as the participation of workers in co-working spaces in local community initiatives, their contribution to urban revitalization trends, and micro-scale physical transformations. The paper, therefore, helps to fill the gap in the literature about the location patterns of these new working spaces and their urban effects at different scales, both in terms of urban spaces and practices.  相似文献   

    

Maria Lúcia G. Monteiro  Eliane T. Mársico  Anna Carolina V. da C. S. Canto  Bruno R. C. da Costa‐Lima  Marion P. da Costa  Fernanda M. Viana  Teofilo J. P. da Silva  Carlos A. Conte‐Junior 《Journal of food science》2017,82(4):1028-1036

The influence of different ultraviolet (UV‐C) doses (0.103 and 0.305 J/cm²) was investigated by instrumental color parameters, pH, lipid, and protein oxidations, fatty acids (FA) composition and biogenic amines (BAs) in Nile tilapia fillets during 11 d at 4 ± 1 °C. The UV‐C treatment increased (P < 0.05) a^* values and protein oxidation in a dose‐dependent manner, and delayed (P < 0.05) the formation of BAs over the course of the storage period. L^* values and lipid oxidation were not influenced (P > 0.05) by UV‐C light. Fillets treated with a low UV‐C dose exhibited greater (P < 0.05) total polyunsaturated fatty acid (PUFA) than their untreated counterparts. Therefore, a low UV‐C dose can be recommended in tilapia fillets as an alternative processing method to control pH and BAs, as well as improve the total PUFA amount and overall nutritional quality.  相似文献   

    

Hércules Bezerra Dias  Maria Inês Basso Bernardi  Matheus Aparecido dos Santos Ramos  Tamara Carolina Trevisan  Taís Maria Bauab  Antônio Carlos Hernandes  Alessandra Nara de Souza Rastelli 《Microscopy research and technique》2017,80(6):634-643

The aim of this study was to evaluate the antibacterial activity of a composite resin modified by 3D zinc oxide (ZnO) microstructures and to verify possible alterations on its mechanical properties. ZnO was synthesized by hydrothermal approach and characterized by X‐ray diffraction (XRD), surface area by Brunauer, Emmett and Teller (BET), Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy (FESEM). The minimum inhibitory concentrations of ZnO against Streptococcus mutans, Escherichia coli, Staphylococcus aureus, and Candida albicans were determinated. The composite resin Filtek^TM Z350XT (3M of Brazil) was blended with 0.2%, 0.5%, and 1% in weight of ZnO and submitted to antibacterial assay by direct contact test against S. mutans, the leading cause of dental caries and the most cariogenic oral streptococci. Additionally, it was performed compressive and diametral tensile strength tests of the modified composite resin. Microrods and hollow microrods of ZnO were obtained and its MIC values were found to be 125 μg/mL for S. mutans, 500 μg/mL for C. albicans and 62.5 μg/mL for S. aureus. For the tested concentrations, it was not found MIC against E. coli. The direct contact test showed a significant antibacterial capacity of modified composite resin (p > 0.05 for all concentrations). The compressive and diametral tensile strength remains no changed after inclusion of microparticles (p > 0.05 for all concentrations). The modification of the composite resin with small amounts of ZnO microparticles significantly inhibited the S. mutans growth on resin surface without significant alterations of its mechanical strength.  相似文献   

    

Fabián González‐Rivas  Carolina Ripolles‐Avila  Fabio Fontecha‐Umaña  Abel Guillermo Ríos‐Castillo  José Juan Rodríguez‐Jerez 《Comprehensive Reviews in Food Science and Food Safety》2018,17(5):1261-1276

Microorganisms can colonize and subsequently form biofilms on surfaces, which protect them from adverse conditions and make them more resistant than their planktonic free‐living counterparts. This is a major concern in the food industry because the presence of biofilms has significant implications for microbial food contamination and, therefore, for the transmission of foodborne diseases. Adequate hygienic conditions and various preventive and control strategies have consequently been developed to ensure the provision of safe, good‐quality food with an acceptable shelf‐life. This review focuses on the significance of biofilms in the food industry by describing the factors that favor their formation. The interconnected process among bacteria known as “quorum sensing,” which plays a significant role in biofilm development, is also described. Furthermore, we discuss recent strategic methods to detect, quantify, and remove biofilms formed by pathogenic bacteria associated with food processing environments, focusing on the complexity of these microbial communities.  相似文献   

    

Ana Carolina Pelaes Vital  Nadine Woruby Santos  Paula Toshimi Matumoto‐Pintro  Monica Regina da Silva Scapim  Grasiele Scaramal Madrona 《International Journal of Dairy Technology》2018,71(1):183-189

Grape juice residue was incorporated into ice cream at 2.5%, 5.0% and 10.0% to obtain a product with functional characteristics. The chemical composition, colour, total phenolic compounds, antioxidant capacity and sensory acceptance of the ice creams were analysed at day 0 and after 40 days of storage. Ice creams containing grape juice residue had a higher concentration of phenolic compounds and antioxidant activity compared to the control samples. Consumers’ acceptance was similar for all products. At the end of storage, the polyphenol content and antioxidant activity had decreased. Grape juice residue has potential as a natural source of antioxidants to develop new products.  相似文献   

    

Patricia Ribeiro Pereira  Anna Carolina Nitzsche Teixeira Fernandes Corrêa  Mauricio Afonso Vericimo  Vânia Margaret Flosi Paschoalin 《Comprehensive Reviews in Food Science and Food Safety》2018,17(4):878-891

Taro (Colocasia esculenta) corm is a rustic staple food, rich in small starch granules, fibers, and bioactive phytoconstituents such as flavonoids, alkaloids, sterols, tannins, phytates, micronutrients, and proteins, including tarin, a GNA‐related lectin. Tarin exhibits recognized biocide activities against viruses and insects, has antitumoral properties and is an immunomodulator molecule candidate. It has been isolated in highly purified form (>90%) from taro corms through low‐cost and single‐step affinity chromatography. It comprises 2‐domain 27 to 28 kDa protomer, posttranslational cleaved into 2 nonidentical monomers, 11.9 and 12.6 kDa, held by noncovalent binding. At least 10 tarin isoforms sharing over 70% similarity have been described. The monomers assume the β‐prism II fold, consisting of 3 antiparallel β‐sheets formed by 4 β‐strands each. Tarin exhibits an expanded‐binding site for complex and high‐mannose N‐glycan chains 49, 212, 213, 358, 465, and 477 found on cell surface antigens of viruses, insects, cancer, and hematopoietic cells, explaining its broad biological activities. Tarin may stimulate innate and adaptive immune responses, enabling hosts to recover from infections or immunosuppressed status inherent to several pathological conditions. In a murine model, tarin stimulates the in vitro and in vivo proliferation of total spleen and bone marrow cells, especially B lymphocytes. Granulocyte repopulation has also been demonstrated in long‐term mice bone marrow cell cultures. As a potential immunomodulator, tarin, administered to immunosuppressed mice, attenuated cyclophosphamide‐induced leukopenia. We propose a molecular model that unites the potential prophylactic and therapeutic action of tarin on hematopoietic and cancer cells, as a potential immunomodulator.  相似文献   

    

Ewelina Patyra  Carolina Nebot  Rosa Elvira Gavilán  Alberto Cepeda  Krzysztof Kwiatek 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2018,35(5):882-891

A new multi-compound method for the analysis of veterinary drugs, namely tiamulin, trimethoprim, tylosin, sulfadiazine and sulfamethazine was developed and validated in medicated feeds. After extraction, the samples were centrifuged, diluted in Milli-Q water, filtered and analysed by high performance liquid chromatography coupled to tandem mass spectrometry. The separation of the analytes was performed on a biphenyl column with a gradient of 0.1% formic acid in acetonitrile and 0.1% formic acid in Milli-Q water. Quantitative validation was done in accordance with the guidelines laid down in European Commission Decision 2002/657/EC. Method performances were evaluated by the following parameters: linearity (R² < 0.99), precision (repeatability <14% and within-laboratory reproducibility <24%), recovery (73.58–115.21%), sensitivity, limit of detection (LOD), limit of quantification (LOQ), selectivity and expanded measurement uncertainty (k. = 2). The validated method was successfully applied to the 2 medicated feeds obtained from the interlaboratory studies and feed manufactures from Spain in August 2017. In these samples, tiamulin, tylosin and sulfamethazine were detected at the concentration levels declared by the manufacturers. The developed method can therefore be successfully used to routinely control the content and homogeneity of these antibacterial substances in medicated feed.

Abbreviations

AAFCO – Association of American Feed Control Officials; TYL – tylosin; TIAM – tiamulin fumarate; TRIM – trimethoprim; SDZ – sulfadiazine; SMZ – sulfamethazine; UV – ultraviolet detector; FLD – fluorescence detector; HPLC – high performance liquid chromatography; MS/MS – tandem mass spectrometry; LOD – limit of detection; LOQ – limit of quantification; CV – coefficient of variation; SD – standard deviation; U – uncertainty  相似文献