Alginate-Based Carriers Loaded with Mulberry (Morus alba L.) Leaf Extract: A Promising Strategy for Prolonging 1-Deoxynojirimicyn (DNJ) Systemic Activity for the Nutraceutical Management of Hyperglycemic Conditions

The iminosugar 1-deoxynojirimicyn (DNJ) contained in mulberry leaves has displayed systemic beneficial effects against disorders of carbohydrate metabolism. Nevertheless, its effect is impaired by the short half-life. Alginate-based carriers were developed to encapsulate a DNJ-rich mulberry extract: Ca-alginate beads, obtained by external gelation, and spray-dried alginate microparticles (SDMs). Mean size and distribution, morphology, drug loading, encapsulation efficiency, experimental yield, and release characteristics were determined for the two formulations. Ca-alginate beads and SDMs exhibited an encapsulation efficiency of about 54% and 98%, respectively, and a DNJ loading in the range of 0.43-0.63 μg/mg. The in vitro release study demonstrated the carriers' capability in controlling the DNJ release in acid and basic conditions (<50% in 5 h), due to electrostatic interactions, which were demonstrated by 1H-NMR relaxometry studies. Thus, alginate-based particles proved to be promising strategies for producing food supplements containing mulberry leaf extracts for the management of hyperglycemic state.

Combining photocatalytic collection and degradation of microplastics using self-asymmetric Pac-Man TiO2

Microplastics are a significant environmental threat and the lack of efficient removal techniques further amplifies this crisis. Photocatalytic semiconducting nanoparticles have the potential to degrade micropollutants, among them microplastics. The hydrodynamic effects leading to the propulsion of micromotors can lead to the accumulation of microplastics in close vicinity of the micromotor. Incorporating these different properties into a single photocatalytic micromotor (self-propulsion, phoretic assembly of passive colloids and photocatalytic oxidation of contaminants), we achieve a highly scalable, inherently-asymmetric Pac-Man TiO2 micromotor with the ability to actively collect and degrade microplastics. The target microplastics are homogeneous polystyrene microspheres (PS) to facilitate the optical degradation measurements. We cross-correlate the degradation with catalytic activity studies and critically evaluate the timescales required for all involved processes.

New Eco-Friendly and Low-Energy Synthesis to Produce ZnO Nanoparticles for Real-World Scale Applications

This paper presents an original and sustainable method for producing ZnO nanoparticles (NPs) in response to global challenges (low energy requirements, low environmental impact, short production times, and high production yield). The method is based on an ion exchange process between an anionic resin and an aqueous ZnCl2 solution; it operates in one step at room temperature/ambient pressure without the need for complex apparatus or purification steps. From the kinetics, we observed the formation of pure simonkolleite, a zinc-layered hydroxide salt (Zn5(OH)8Cl2·H2O), after only 5 min of reaction. This compound, used elsewhere as a ZnO precursor after calcination at high temperatures, here decomposes at room temperature into ZnO, allowing extraordinary savings of time and energy. Finally, in only 90 min, pure and crystalline ZnO NPs are obtained, with a production yield > 99%. Several types of aggregates resulting from the self-assembly of small hexagonal platelets (solid or hollow in shape) were observed. Using our revolutionary method, we produced almost 10 kg of ZnO NPs per week without any toxic waste, significantly reducing energy consumption; this method allows transferring the use of these unique NPs from the laboratory environment to the real world.

Low environmental impact remediation of microplastics: Visible-light photocatalytic degradation of PET microplastics using bio-inspired C,N-TiO2/SiO2 photocatalysts

Microplastics (MPs) are plastic particles with sizes between 1 μm and 5 mm with a ubiquitous presence in aquatic ecosystems. MPs harm marine life and can cause severe health problems for humans. Advanced oxidation processes (AOPs) that involve the in-situ generation of highly oxidant hydroxyl radicals can be an alternative to fight MPs pollution. Of all the AOPs, photocatalysis has been proven a clean technology to overcome microplastic pollution. This work proposes novel C,N-TiO₂/SiO₂ photocatalysts with proper visible-active properties to degrade polyethylene terephthalate (PET) MPs. Photocatalysis was performed in an aqueous medium and at room temperature, evaluating the influence of two pH values (pH 6 and 8). The results demonstrated that the degradation of the PET MPs by C,N-TiO₂/SiO₂ semiconductors is possible, achieving mass losses between 9.35 and 16.22 %.

Correlating the physico-chemical properties of two conventional glazed porcelain stoneware tiles in relation to cleanability and sanitization

Keeping surfaces clean can reduce the spread of infections. In particular, to decrease the potential for SARS CoV-2 contamination, performing disinfection of high-touching surfaces. Several ceramic tiles and porcelain stoneware tiles with antimicrobial properties are already available on the market. However, the widespread use of antimicrobial glazed stoneware tiles may require to replace the ceramic surfaces already present in many buildings. The unfeasibility of such replacement can be due to both product durability (lifetime of a tile is usually long) and/or monetary restrictions. Furthermore, as porcelain stoneware per se does not have antimicrobial activity, these materials are fabricated by adding chemical agents able to provide antimicrobial properties. This approach requires a compatibility between the antimicrobial agents and the glaze formulation, as well as a careful control of the firing cycle and the final properties of the ceramic products. It follows that the final cost of antimicrobial tiles is not competitive with that of conventional tiles. In the latter, the persistence of potential pathogens on the surfaces is a crucial problem to face: the longer a pathogen survives on a surface, the longer it may be a source of transmission and thus endanger susceptible subjects. In this work, bacteria's capacity to adhere and to be effectively removed from two conventional glazed porcelain stoneware tiles (under dirty and clean conditions) was investigated. Two different glazes were tested, one mainly glassy (glossy) and the other mainly crystalline (matt). The sanitization procedures were carried out by chemical and chemo-mechanical procedures. The results showed that chemo-mechanical sanitization was the most effective, and the best results could be obtained on the stoneware tiles coated with the mainly glassy glaze, with the lowest porosity and the lower roughness values and water contact angles, especially under clean conditions.

Mine Clay Washing Residues as a Source for Alkali-Activated Binders

The aim of this paper is to promote the use of mine clay washing residues for the preparation of alkali activated materials (AAMs). In particular, the influence of the calcination temperature of the clayey by-product on the geopolymerization process was investigated in terms of chemical stability and durability in water. The halloysitic clay, a mining by-product, has been used after calcination and mixed with an alkaline solution to form alkali activated binders. Attention was focused on the influence of the clay’s calcination treatment (450–500–600 °C) on the geopolymers’ microstructure of samples, remaining in the lower limit indicated by the literature for kaolinite or illite calcination. The mixtures of clay and alkali activators (NaOH 8M and Na-silicate) were cured at room temperature for 28 days. The influence of solid to liquid ratio in the mix formulation was also tested in terms of chemical stability measuring the pH and the ionic conductivity of the eluate after 24-h immersion time in water. The results reported values of ionic conductivity higher for samples made with untreated clay or with low temperature of calcination (≥756 mS/m) compared with values of samples made with calcined clay (292 mS/m). This result suggests that without a proper calcination of the as-received clay it was not possible to obtain 25 °C-consolidated AAMs with good chemical stability and dense microstructure. The measures of integrity test, pH, and ionic conductivity in water confirmed that the best sample is made with calcined clay at 600 °C, being similar (53% higher ionic conductivity of the eluate) or equal (integrity test and pH) to values recorded for the metakaolin-based geopolymer considered the reference material. These results were reflected in term of reticulation and morphology of samples through the analysis with scanning electron microscope (SEM) and X-ray diffraction (XRD), which show a dense and homogeneous microstructure predominantly amorphous with minor amounts of quartz, halloysite, and illite crystalline phases. Special attention was dedicated to this by-product to promote its use, given that kaolinite (and metakaolin), as primary mineral product, has a strong impact on the environment. The results obtained led us to consider this halloysite clay very interesting as an aluminosilicate precursor, and extensively deepening its properties and reactivity for the alkaline activation. In fact, the heart of this work is to study the possibility of reusing this by-product of an industrial process to obtain more sustainable high-performance binders.

The Role of the Reactive Species Involved in the Photocatalytic Degradation of HDPE Microplastics Using C,N-TiO2 Powders

Microplastics (MPs) are distributed in a wide range of aquatic and terrestrial ecosystems throughout the planet. They are known to adsorb hazardous substances and can transfer them across the trophic web. To eliminate MPs pollution in an environmentally friendly process, we propose using a photocatalytic process that can easily be implemented in wastewater treatment plants (WWTPs). As photocatalysis involves the formation of reactive species such as holes (h+), electrons (e-), hydroxyl (OH●), and superoxide ion (O2●-) radicals, it is imperative to determine the role of those species in the degradation process to design an effective photocatalytic system. However, for MPs, this information is limited in the literature. Therefore, we present such reactive species' role in the degradation of high-density polyethylene (HDPE) MPs using C,N-TiO2. Tert-butanol, isopropyl alcohol (IPA), Tiron, and Cu(NO3)2 were confirmed as adequate OH●, h+, O2●- and e- scavengers. These results revealed for the first time that the formation of free OH● through the pathways involving the photogenerated e- plays an essential role in the MPs' degradation. Furthermore, the degradation behaviors observed when h+ and O2●- were removed from the reaction system suggest that these species can also perform the initiating step of degradation.

In vivo β-carotene skin permeation modulated by Nanostructured Lipid Carriers

Nanostructured Lipid Carriers (NLC) were investigated with the purpose of promoting skin permeation of the highly lipophilic β-carotene (BC) across the stratum corneum (SC) barrier so that it may perform its antioxidant properties in photo-aging and epithelial skin cancer prevention. Two differently sized NLC samples were developed using stearic acid and squalene as lipid matrix and evaluated in comparison with Microstructured Lipid Carriers (MLC). The carriers were characterized for morphology, size, Z-potential, BC loading and release as well as physical state by means of DSC and XRPD analyses. In vivo penetration of the carriers was assessed on humans by determining BC concentrations within the SC stratum disjunctum and stratum compactum layers removed by means of the tape stripping test in comparison with pure BC. Unlike MLC and pure BC that were mostly retained within the outermost layers of the SC, the NLC sample having the smallest size (about 200 nm) has proved to penetrate more deeply into the SC barrier. Accordingly, the goal of providing β-carotene actions against oxidative damages within the looser skin viable tissues could be envisaged.

Microplastic pollution reduction by a carbon and nitrogen-doped TiO2: Effect of pH and temperature in the photocatalytic degradation process

Microplastics (MPs) are pollutants formed by plastics ≤ 5 mm and are present in marine and terrestrial environments. Due to their large surface to volume ratio and chemical surface properties, MPs adsorb hazardous chemicals from their surrounding environment. When MPs are consumed by fauna, they transfer those substances through the trophic chain. An essential issue of MPs is their disposal. Due to their size, the disposal methods commonly used for plastic items are not suited for MPs. Here, photocatalysis in an aqueous medium is proposed as an alternative to fight MPs pollution. Although the photocatalysis of MPs has been reported, the effect of operating variables in the process has not been investigated. To fill this gap, the impact of pH and temperature on the degradation process of HDPE MPs was investigated using C,N-TiO₂ and visible light. Degradation was followed by mass loss, carbonyl index calculation and microscopy. It was found that photocatalysis at low temperature (0 °C) increases MPs' surface area by fragmentation, and low pH value (pH 3) favours hydroperoxide formation during photooxidation. By using the design of experiments tool, it was demonstrated that there is a combined effect of pH and temperature in the photocatalysis of HDPE MPs.

In Vivo Biodistribution of Respirable Solid Lipid Nanoparticles Surface-Decorated with a Mannose-Based Surfactant: A Promising Tool for Pulmonary Tuberculosis Treatment?

The active targeting to alveolar macrophages (AM) is an attractive strategy to improve the therapeutic efficacy of ‘old’ drugs currently used in clinical practice for the treatment of pulmonary tuberculosis. Previous studies highlighted the ability of respirable solid lipid nanoparticle assemblies (SLNas), loaded with rifampicin (RIF) and functionalized with a novel synthesized mannose-based surfactant (MS), both alone and in a blend with sodium taurocholate, to efficiently target the AM via mannose receptor-mediated mechanism. Here, we present the in vivo biodistribution of these mannosylated SLNas, in comparison with the behavior of both non-functionalized SLNas and bare RIF. SLNas biodistribution was assessed, after intratracheal instillation in mice, by whole-body real-time fluorescence imaging in living animals and RIF quantification in excised organs and plasma. Additionally, SLNas cell uptake was determined by using fluorescence microscopy on AM from bronchoalveolar lavage fluid and alveolar epithelium from lung dissections. Finally, histopathological evaluation was performed on lungs 24 h after administration. SLNas functionalized with MS alone generated the highest retention in lungs associated with a poor spreading in extra-pulmonary regions. This effect could be probably due to a greater AM phagocytosis with respect to SLNas devoid of mannose on their surface. The results obtained pointed out the unique ability of the nanoparticle surface decoration to provide a potential more efficient treatment restricted to the lungs where the primary tuberculosis infection is located.

Innovative thermal and acoustic insulation foam by using recycled ceramic shell and expandable styrofoam (EPS) wastes

Ceramic foams were produced using ceramic shell (mullite source), an industrial solid waste from the precision casting process, and expandable styrofoams, EPS (d₅₀ < 1 mm) as pore former, envisaging thermal and acoustic insulation applications. Physical, chemical, structural properties of the selected raw materials (wastes) were characterized. The influence of the amount and morphology of the EPS powder beads on the microstructure, thermal conductivity, acoustic absorption and compressive strength of ceramic shell foams were evaluated. Batches containing well mixed ceramic shell powder (d₅₀ < 2 µm), EPS beads, in different proportions (from 10 to 70 vol%), were added as pore forming agent, and BonderPlus® (Na₂SiO₃ solution) were uniaxially pressed at 20 MPa, dried and fired in controlled conditions. The experimental results showed that homogeneous microstructures of elongated and interconnected pores with sizes between 115 and 1200 µm can be obtained. These connections exhibit a significant impact on the thermal/sound absorption properties, as a consequence of the interaction between air molecules within the pores through the passage of the thermal/sound wave. Ceramic shell foams (containing 70 vol% of EPS powder beads) featured porosities up to 77%, thermal conductivity of 0.061 W/mK, sound absorption coefficient of ∼0.9 (3 kHz), and excellent compressive strength ∼5.4 MPa. In addition, the use of ceramic shells wastes for the manufacture of acoustic and thermal insulators with suitable microstructural characteristics is a great sustainable opportunity, since with the use of this refractory waste, is possible to avoid the release to the atmosphere of about 3.1 kg of CO₂ per kg of manufactured material.

Lime-cement textile reinforced mortar (TRM) with modified interphase

BACKGROUND:

Lack of interphase compatibility between the fabric and the matrix significantly impairs the load-bearing capacity of textile reinforced mortar (TRM). In this study, we consider the application of two inorganic surface coatings for enhancing the interphase bond properties.

METHODS:

Either of two silica-based coatings, namely nano- and micro-silica, were applied to alkali-resistant glass (ARG) and to hybrid carbon-ARG woven fabric. Mechanical performance of TRM reinforced with the uncoated and the coated fabric was compared in uniaxial tensile tests.

RESULTS:

Mechanical testing provides evidence of a remarkable enhancement in terms of ultimate strength and deformability for the coated specimens. This effect can be ascribed to the improved hydrophilicity of the fibers' surface and to the activation of pozzolanic reaction at the interphase. In addition, penetration of nano- and microparticles in the bundle of the textile yarns reduces the occurrence of telescopic failure.

Immobilization of monolayer protected lipophilic gold nanorods on a glass surface

We present a novel process of immobilization of gold nanorods (GNRs) on a glass surface. We demonstrate that by exploiting monolayer protection of the GNRs, their unusual optical properties can be completely preserved. UV-visible spectroscopy and atomic force microscopy analysis are used to reveal the optical and morphological properties of monolayer protected immobilized lipophilic GNRs, and molecular dynamics simulations are used to elucidate their surface molecule arrangements.

Bentonite-based organoclays as innovative flame retardants agents for SBS copolymer

Two organophilic bentonites, based on nitrogen-containing compounds, have been synthesised via ion exchange starting from pristine bentonite with octadecyltrimethylammonium bromide (OTAB) and with synthetic melamine-derived N2,N4-dihexadecyl-1,3,5-triazine-2,4,6-triamine (DEDMEL). The chemical and morphological characterization of the organoclays was based on XRD, TEM, Laser Granulometry, X-Ray Fluorescence and CEC capacity. Copoly(styrene-butadiene-styrene)-nanocomposites (SBS-nanocomposites) were obtained by intercalation of the SBS-copolymer into these new organoclays by melt intercalation method. XRD and TEM analysis of the organoclays and of the micro/nano-composites obtained are presented. The effect of the organoclays on the SBS-nanocomposite's flammability properties was investigated using cone calorimeter. An encouraging decrease of 20% in the peak heat released rate (PHRR) has been obtained confirming the important role of melamine's based skeleton and its derived organoclays to act as effective fire retardants and for the improvement of this important functional property in SBS copolymers.

The structure of ZrO2phases and devitrification processes in a Ca–Zr–Si–O-based glass ceramic: a combined a-XRD and XAS study

The structure of the Zr atomic environment in a CaO–ZrO2–SiO2glass ceramic as a function of thermal treatments has been studied, combining X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD) and anomalous XRD (a-XRD) techniques. The analysis of XRD patterns demonstrates that the devitrification process proceeds through the partial segregation of Zr-depleted phases (wollastonite-like) and Zr-rich phases (Zr oxides). The XAS and a-XRD measurements at the ZrK-edge have been exploited in order to obtain a closer insight into the atomic structure around the Zr atoms. In the as-quenched glass the Zr atom is sixfold coordinated to O atoms in an amorphous environment rich in Ca and Si. Thermal treatment firstly (T= 1273–1323 K) causes partial segregation of Zr in the form of an oxide with a tetragonal zirconia (t-ZrO2) crystalline structure. Raising the temperature (T= 1373 K) causes the formation of ZrO2crystallites in the monoclinic crystallographic phase (baddeleyite, m-ZrO2). Analysis of the XAS data shows that a considerable amount of Zr remains in an amorphous calcium silicate phase.

Differential anomalous wide-angle X-ray scattering and X-ray absorption experiments to investigate the formation of glass ceramics in the CaO–SiO2–ZrO2system

The structure of a CaO–SiO2–ZrO2-based glass ceramic has been investigated by X-ray diffraction, X-ray absorption spectroscopy and differential anomalous scattering techniques as a function of the thermal treatment of the sample. The microstructure of the glass has been investigated at room temperature, before the recrystallization of the glass ceramic, and on two samples annealed at 1073 and 1273 K for 1 h to follow the early stages of nucleation of the quartz and wollastonite crystalline phases. Indications on the roles of Ca, Si and Zr during the devitrification process are given.