Nutrients Bioaccessibility and Anti-inflammatory Features of Fermented Bee Pollen: A Comprehensive Investigation

We compared raw bee-collected pollen (Raw-BCP), spontaneously fermented BCP (Unstarted-BCP), and BCP fermented with selected microbial starters (Started-BCP) to deepen whether fermentation may favorably affect the nutrients bioaccessibility and functional features of BCP. Under in vitro gastrointestinal batches, the highest serum-availability of phenolic compounds was found in Started-BCP, highlighting the positive effect exerted by selected microbial starters. The same effect was not found in spontaneously fermented BCP. In colon adenocarcinoma cell line-2 (Caco-2) cells stressed by a pro-inflammatory stimulus, the treatment with Started-BCP halted the increase of pro-inflammatory mediator’s level. Started-BCP counteracted efficiently the deleterious effects of inflammatory stimuli on the integrity of the Caco-2 cells monolayer and its barrier function. Started-BCP successfully counteracted the H2O2-induced intracellular accumulation of reactive oxygen species (ROS) in Caco-2 cells. A protective role against lipopolysaccharide (LPS)-induced inflammation was exerted by Started-BCP in human keratinocytes. The same protective effects on Caco-2 and keratinocyte cell lines were negligible after treatments with Raw-BCP or Unstarted-BCP

Sulfate Reducing Bacteria as Bio-cleaning Agents: Development of New Methodologies and Study Cases

In the last decades, the contribution of different scientific disciplines in the field of restoration and conservation of cultural heritage to finding alternative methods of investigation that are even more effective and fully respect artworks, operators and environment, has greatly increased. An example is the University of Milan patent that provides for the use of some specialized bacteria as cleaning agents. This method, known as biocleaning, is based on the use of Desulfovibrio vulgaris, a sulfate reducing bacterium, for the removal of sulfate alterations from stone surfaces. Recently, the university spin-off Micro4yoU purchased the patent by initiating a series of investments aimed at enhancing the commercial product from prototype. The present work describes: the desulfation mechanism operated by Desulfovibrio vulgaris and the technological shift necessary to obtain a biological formulation usable in situ, with two practical case studies

Sulfate Reducing Bacteria as Bio-cleaning Agents: Development of New Methodologies and Study Cases

In the last decades, the contribution of different scientific disciplines in the field of restoration and conservation of cultural heritage to finding alternative methods of investigation that are even more effective and fully respect artworks, operators and environment, has greatly increased.An example is the University of Milan patent that provides for the use of some specialized bacteria as cleaning agents. This method, known as biocleaning, is based on the use of Desulfovibrio vulgaris, a sulfate reducing bacterium, for the removal of sulfate alterations from stone surfaces.Recently, the university spin-off Micro4yoU purchased the patent by initiating a series of investments aimed at enhancing the commercial product from prototype. The present work describes: the desulfation mechanism operated by Desulfovibrio vulgaris and the technological shift necessary to obtain a biological formulation usable in situ, with two practical case studies.Negli ultimi decenni è cresciuto il contributo che le diverse discipline scientifiche hanno dato al recupero e alla conservazione del patrimonio artistico per trovare soluzioni sempre più efficaci e rispettose del bene, dell’operatore e dell’ambiente.Un esempio è un brevetto sviluppato dall’Università degli studi di Milano che prevede l’utilizzo di alcuni specifici batteri come agenti di pulitura. Tale metodo, indicato col termine di bio-pulitura propone, tra gli altri, l’impiego del batterio solfato riduttore Desulfovibrio vulgaris per la rimozione di alterazioni solfatiche da superfici litoidi. Recentemente, il brevetto è stato acquisito dallo spin-off universitario Micro4yoU che ha avviato una serie di investimenti per sviluppare, a partire dal prototipo di laboratorio, un prodotto commerciale.Nel presente lavoro verranno illustrati: il meccanismo di desolfatazione ad opera di Desulfovibrio vulgaris, il processo di trasferimento tecnologico affrontato per ottenere un formulato microbico utilizzabile in cantiere e due casi studio applicativi

Recovery of Shallow Charge-Trapping Defects in CsPbX3 Nanocrystals through Specific Binding and Encapsulation with Amino-Functionalized Silanes

[EN] We report a facile methodology to restore photoluminescence (PL) of CsPbBr3 nanocrystals (NCs) based on their postsynthetic modification with 3-aminopropyltriethoxysilane (APTES). By this methodology, a stark PL recovery factor of near 2-fold was obtained compared to their uncoated counterparts. H-1 NMR studies confirmed the presence of APTES on the NCs shell and provided more insight into the nature of the alkoxysilane passivation mechanisms. We further highlight that, contrary to expectations, preferential attachment of APTES does not take place through their amine terminal groups. The proposed surface-repair strategy can be extended to other halide compositions, yielding similarly effective 4-fold and 2-fold PL enhancements for CsPbCl3 and CsPbI3 NCs, respectively. Our work thus exemplifies that careful management of the perovskite NC interfaces and surface engineering is one of the most important frontiers in this emerging class of optoelectronic materials.This work was financially supported by FEDER projects BiHolog-CTQ2016-75749-R from MINECO and GVA PROMETEO II 2014/40. V.G-P. thanks Universitat Politecnica de Valencia for her postdoctoral fellowship (Grant-PAID-10-14) and for her research mobility grant (UPV- Research mobility Grant-PAID-00-15), and Miguel Cebrian for his help and valuable technical support. S.A.V., N.M., and S.M. acknowledge financial support by the National Research Foundation, Singapore under its Competitive Research Programme (NRF-CRP14-2014-03). S.A.V. thanks Alasdair Brown for help with the nanocrystal syntheses.González-Pedro, V.; Veldhuis, SA.; Begum, R.; Bañuls Polo, M.; Bruno, A.; Mathews, N.; Mhaisalka, S.... (2018). Recovery of Shallow Charge-Trapping Defects in CsPbX3 Nanocrystals through Specific Binding and Encapsulation with Amino-Functionalized Silanes. ACS Energy Letters. 3(6):1409-1414. https://doi.org/10.1021/acsenergylett.8b00498S140914143

Generalized Synthesis to Produce Transparent Thin Films of Ternary Metal Oxide Photoelectrodes

Developing facile approaches to prepare non-light-scattering ternary oxide thin film photoelectrodes is an important goal for solar water splitting tandem cells. Herein, a novel synthesis route is reported that employs ethylenediaminetetraacetic acid (EDTA) to enable compatible water solubility of diverse metal cations, which affords transparent films by solution processing. By using BiVO4 as a model material, a remarkable improvement in transparency is demonstrated, quantified by the direct transmittance at 600 nm of >80 % versus the <10 % observed with state-of-the-art electrodeposited thin films while maintaining reasonable solar-driven oxidation photocurrents (1.75 mA cm(-2) in the presence of a sulfite hole scavenger). Furthermore, it is demonstrated that the synthesis technique can be applied in a general fashion towards the synthesis of diverse n- and p-type metal oxide materials, such as ZnFe2O4 and CuFeO2

Ultrafast Charge Carrier Dynamics in CuWO4 Photoanodes

[Image: see text] CuWO(4) is a ternary metal oxide semiconductor with promising properties for photoelectrochemical (PEC) water splitting and solar light conversion, due to its quite low band gap (2.3 eV) and high stability in an alkaline environment. Aiming at understanding the origin of the relatively low PEC efficiency attained with CuWO(4) photoanodes, we here investigate transparent CuWO(4) electrodes prepared by a simple solution-based method through the combination of femtosecond transient absorption spectroscopy with electrochemical, PEC, and photochromic characterizations. The very fast recombination dynamics of the charge carriers photogenerated in CuWO(4), which is the reason for its low efficiency, is discussed in relation with its PEC performance and with the recently calculated band structure of this material, also in comparison with the behavior of other semiconductor oxides employed in PEC applications, in particular Fe(2)O(3)

Strategies for increasing the scale of biocleaning treatment through sulfate crust bioremoval

During the last two decades the role of microorganisms in the conservation of monuments and stone works has been largely acknowledged. Recently, new efforts have been carried on to enhance bacterial performance (e.g.: by selecting natural improved strains or by engineering bacteria), to scale-up the productivity process of bacterial biomass and to improve the delivery system, in order to develop bio-treatments implementable at large scale. \ua0 Despite these promising progresses, the use of bacteria in restoration practice is still limited to small artworks or surface areas. In particular regarding the removal of gypsum encrustation by sulfate reducing bacteria, a major drawback is that the technique is time-consuming in the presence of thick and compact crusts. \ua0 Here, it is proposed a strategy to speed up the bio-cleaning of gypsum crusts by coupling with a chemical pre-treatment. A one-century-old artistic marble statue, affected by sulfate-based crusts and grey deposits, has been treated with a sulfate reducing bacteria (SRB)-based product and a non-ionic detergent, applied singularly and in combination. Both the biological and combined biological-chemical treatments resulted in an affective removal of black crusts but the synergic treatment, even retaining all the advantages of the biocleaning approach, was able to completely remove the alteration taking advantage of a 70% reduction of the number of biological applications. Moreover, the co-treatment removed also a black crust barium sulfate layer, a remnant of a previous restoration treatment. \ua0 The combined biological-chemical treatment offers an economic improvement for large scale restoration processes still retaining the advantages of the biological treatment, i.e. low environmental impact and preservation of the high value conservation patina developed on the sound stone

Key factors boosting the performance of planar ZnFe2O4 photoanodes for solar water oxidation

The performance of ZnFe2O4 photoanodes largely depends on their nanostructure, crystallinity and n-type doping, though decoupling their impact on photoactivity remains a challenge. Herein, the combined effects of the synthesis temperature and reductive annealing post-treatment on the photoelectrochemical performance of planar ZnFe2O4 photoanodes are investigated in relation to a comprehensive range of film thicknesses, enabled by an optimized sol-gel synthetic approach. By eliminating the effects of the nanostructure, a synergistic effect is revealed between the material crystallinity, controlled by the synthesis temperature, and the n-type doping triggered by the H-2-treatment, which is maximum for the thickest photoactive layers. Intensity modulated photocurrent spectroscopy measurements performed in operando evidence the crucial impact of the synthesis temperature and the reductive treatment on inducing effective surface charge injection and improved bulk charge transport, respectively, to enhance the photoelectrochemical performance of planar ZnFe2O4 films.LIMN

Improved Photoelectrochemical Performance of WO3/BiVO4 Heterojunction Photoanodes via WO3 Nanostructuring

International audienceWO3/BiVO4 heterojunction photoanodes can be efficiently employed in photoelectrochemical (PEC) cells for the conversion of water into molecular oxygen, kinetic bottleneck splitting. Composite photoelectrodes possessing a nanoflake-like morphology have been synthesized through multistep process and their PEC performance was investigated comparison to that displaying planar surface similar absorption properties thickness. tests, also presence sacrificial hole scavenger, electrochemical impedance analysis under simulated solar irradiation, incident photon current efficiency measurements highlighted charge transport recombination issues affecting composite successfully overcome by nanostructuring WO3 underlayer electrodes

Nature of Charge Carrier Recombination in CuWO₄ Photoanodes for Photoelectrochemical Water Splitting

CuWO4 is a ternary semiconductor oxide with excellent visible light harvesting properties up to 550 nm and stability at high pH values, which make it a suitable material to build photoanodes for solar light conversion to hydrogen via water splitting. In this work, we studied the photoelectrochemical (PEC) performance of transparent CuWO4 electrodes with tunable light absorption and thickness, aiming at identifying the intrinsic bottlenecks of photogenerated charge carriers in this semiconductor. We found that electrodes with optimal CuWO4 thickness exhibit visible light activity due to the absorption of long-wavelength photons and a balanced electron and hole extraction from the oxide. The PEC performance of CuWO4 is light-intensity-dependent, with charge recombination increasing with light intensity and most photogenerated charge carriers recombining in bulk sites, as demonstrated by PEC tests performed in the presence of sacrificial agents or cocatalysts. The best-performing 580 nm thick CuWO4 electrode delivers a photocurrent of 0.37 mA cm–2 at 1.23 VSHE, with a 7% absorbed photon to current efficiency over the CuWO4 absorption spectrum