Enhanced Bioactivity of Pomegranate Peel Extract following Controlled Release from CaCO3 Nanocrystals

none9Pomegranate peel extract is rich of interesting bioactive chemicals, principally phenolic compounds, which have shown antimicrobial, anticancer, and antioxidative properties. The aim of this work was to improve extract’ bioactivity through the adsorption on calcium carbonate nanocrystals. Nanocrystals revealed as efficient tools for extract adsorption reaching 50% of loading efficiency. Controlled release of the contained metabolites under acidic pH has been found, as it was confirmed by quantitative assay and qualitative study through NMR analysis. Specific functionality of inorganic nanocarriers could be also tuned by biopolymeric coating. The resulting coated nanoformulations showed a great antimicrobial activity against B. cinerea fungus preventing strawberries disease better than a commercial fungicide. Furthermore, nanoformulations demonstrated a good antiproliferative activity in neuroblastoma and breast cancer cells carrying out a higher cytotoxic effect respect to free extract, confirming a crucial role of nanocarriers. Finally, pomegranate peel extract showed a very high radical scavenging ability, equal to ascorbic acid. Antioxidant activity, measured also in intracellular environment, highlighted a protective action of extract-adsorbed nanocrystals twice than free extract, providing a possible application for new nutraceutical formulations.Regione Puglia, Project Research for Innovation (REFIN) “Sintesi di un sistema teranostico a base di nano-cellulosa per la detection e la cura dei tumori” Ministero dello Sviluppo Economico, bando “AGRIFOOD” D.M. 5 marzo 2018 Capo III. Prog. N. F/200060/01-03/X45 PERSEFONE - Punica granatum e Nanotecnologie: una value chain per la valorizzazione degli scarti e sottoprodotti finalizzata alla produzione di integratori alimentari e compost. PON Ricerca e Innovazione 2014-2020 - Avviso per la presentazione di progetti dei Ricerca Industriale e Sviluppo Sperimentale nelle 12 aree di specializzazione individuate dal PNR 2015 – 2020, di cui al Decreto Direttoriale MIUR del 13 luglio 2017, n. 1735 NanotEcnologie chiMiche green per la protEzione Sostenibile delle pIante (NEMESI) ARS01_01002 Area di Specializzazione “Chimica Verde” CUP: F36C18000180005, Ministero dell'Università e Ricerca. “Olivicoltura e difesa da Xylella fastidiosa e da insetti vettori in Italia - (Oli.Di.X.I.It)”, prot. Mipaaf n.0011485 del 05/04/2017 Ministry of Agricultural, Food and Forestry Policies.openFrancesca Baldassarre; Viviana Vergaro; Federica De Castro; Francesca Biondo; Gian Paolo Suranna; Paride Papadia; Francesco P. Fanizzi; Domenico Rongai; Giuseppe CiccarellaBaldassarre, Francesca; Vergaro, Viviana; DE CASTRO, Federica; Biondo, Francesca; Suranna, Gian Paolo; Papadia, Paride; Fanizzi, Francesco P.; Rongai, Domenico; Ciccarella, Giusepp

Enhancing Dye-Sensitized Solar Cell Performances by Molecular Engineering: Highly Efficient π-Extended Organic Sensitizers

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Перевод котельной месторождения в районе г. Нижневартовска на водогрейный режим.

Целью работы является перевод котла ДКВр-10-13 с парового режима работы в водогрейный. В связи с поставленной задачей была подобрана схема перевода парового котла ДКВр-10-13 в водогрейный режим, проведен тепловой, гидравлический и аэродинамический расчет котла, технико-экономический расчет котельной, а так же рассмотрены вопросы безопасности жизнедеятельности работников котельной.The aim is to transfer the boiler DKVr-10-13 with steam mode to hot water. In connection with the task of thermal, hydraulic and aerodynamic calculation of the boiler, technical and economic calculation boiler, as well as the issues of life safety professionals boiler was selected transfer circuit boiler DKVr-10-13 in hot water mode performed

In Situ Formation of Zwitterionic Ligands: Changing the Passivation Paradigms of CsPbBr3 Nanocrystals

CsPbBr3 nanocrystals (NCs) passivated by conventional lipophilic capping ligands suffer from colloidal and optical instability under ambient conditions, commonly due to the surface rearrangements induced by the polar solvents used for the NC purification steps. To avoid onerous postsynthetic approaches, ascertained as the only viable stability-improvement strategy, the surface passivation paradigms of as-prepared CsPbBr3 NCs should be revisited. In this work, the addition of an extra halide source (8-bromooctanoic acid) to the typical CsPbBr3 synthesis precursors and surfactants leads to the in situ formation of a zwitterionic ligand already before cesium injection. As a result, CsPbBr3 NCs become insoluble in nonpolar hexane, with which they can be washed and purified, and form stable colloidal solutions in a relatively polar medium (dichloromethane), even when longly exposed to ambient conditions. The improved NC stability stems from the effective bidentate adsorption of the zwitterionic ligand on the perovskite surfaces, as supported by theoretical investigations. Furthermore, the bidentate functionalization of the zwitterionic ligand enables the obtainment of blue-emitting perovskite NCs with high PLQYs by UV-irradiation in dichloromethane, functioning as the photoinduced chlorine source.publishedVersionPeer reviewe

Impact of Precatalyst Activation on Suzuki-Miyaura Catalyst-Transfer Polymerizations: New Mechanistic Scenarios for Pre-transmetalation Events

The relevance of L_nPdX₂ precatalyst activation on the Suzuki-Miyaura reaction course was investigated in the case of catalyst-transfer polymerizations. A catalytic study, backed up by theoretical calculations, allowed to ascertain the coexistence of a neutral and an anionic mechanistic pathways in the precatalyst activation, in which the bulky ^<i>t</i>Bu₃P external ligand plays a crucial role. The fine-tuning of the catalytic conditions can steer the activation step toward the anionic pathway, leading to the full control over the polymerization course. While providing insights and perspectives into the catalyst-transfer polymerizations, these results uncover unexplored scenarios for the pre-transmetalation events of Suzuki-Miyaura reactions contributing to its full understanding

Implementation of Sustainable Solvents in Green Polymerization Approaches

In modern polymer chemistry directed toward the synthesis of conjugated materials, the synthetic routes devised to achieve the process sustainability are based on CH bond activation. This prerequisite distinguishes both the tandem Suzuki−Heck as well as the direct arylation polymerizations (DArP); however, their compatibility with environmentally benign solvents still represents a challenge. In this paper, the implementation of sustainable solvents for the synthesis of poly(9,9-dioctylfluorenylene-vinylene) by using the traditional Pd(AcO)2/P(o-Tol)3/NEt3 catalytic system is described. It is assessed that selected green solvents (i.e., anisole and propylene carbonate) constitute the ideal media for the tandem Suzuki–Heck polymerization. Furthermore, by modulating medium polarity using mixtures of these green solvents and changing the reaction temperature, a suitable compromise between high molecular weights and regioregularity of the resulting polymers is reached. Conversely, the presence of propylene carbonate is deleterious for the DArP of 2-bromo-3-hexylthiophene, while it is found that catalyst performances in anisole strictly depend on the palladium source used. The best conditions are obtained using PdCl2(PPh3)2 as the precatalyst, affording a highly regioregular (93%) poly(3-hexylthiophene) in quantitative yields and high molecular weights (26.7 kg mol−1)

The Dynamic Organic/Inorganic Interface of Colloidal PbS Quantum Dots

Colloidal quantum dots are composed of nanometer-sized crystallites of inorganic semiconductor materials bearing organic molecules at their surface. The organic/inorganic interface markedly affects forms and functions of the quantum dots, therefore its description and control are important for effective application. Herein we demonstrate that archetypal colloidal PbS quantum dots adapt their interface to the surroundings, thus existing in solution phase as equilibrium mixtures with their (metal-)organic ligand and inorganic core components. The interfacial equilibria are dictated by solvent polarity and concentration, show striking size dependence (leading to more stable ligand/core adducts for larger quantum dots), and selectively involve nanocrystal facets. This notion of ligand/core dynamic equilibrium may open novel synthetic paths and refined nanocrystal surface-chemistry strategies

Chemical analysis of cesium lead-halide perovskite nanocrystals by total-reflection X-ray fluorescence spectroscopy

Cesium lead-halide perovskite nanocrystals are an emerging class of materials which potentially have different applications due to the several physical properties they exhibit. These properties are strongly dependent on the elemental composition of the nanocrystals and, to date, only few methods are available for their chemical analysis, such as scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). The present work aims at establishing a new, fast and simple method for the elemental analysis of cesium lead-halide perovskite nanocrystals exploiting total-reflection x-ray fluorescence (TXRF) spectroscopy. The method was validated using a synthetized set of samples and comparing the TXRF results with SEM-EDX data. The sample preparation consisted in suspending the perovskites in 2.0 ml of hexane and sampling 10 μl of the suspension for deposition on a preheated quartz carrier. The element recovery ranged between 82% and 118% for mixed-halide perovskites, while for single halide perovskites it improved to 86%–105%. The present method can be implemented and used also for the elemental characterization of other types of perovskite nanocrystals