Inorganic Particles Research Articles

Revisiting Anode Fast-Charging Capability with Solid Electrolyte Interface Using Cryogenic Transmission Electron Microscopy

The Li+ ion diffusion through the solid electrolyte interphase (SEI) has been widely considered as one of the limiting steps for the Li fast (de)intercalation process. However, a comprehensive understanding of the kinetic limitation of SEI on anode fast-charging remains elusive. Using H-phase (monoclinic) Nb2O5 (H-Nb2O5) as the anode material, we comprehensively studied the fast charging behaviors on both “inorganic SEI free” and “inorganic-rich SEI” anodes with cryogenic transmission electron microscopy (cryo-TEM) and X-ray photoelectron spectroscopy (XPS). The results reveal that there is a negligible difference on the electrochemical performance including fast-charging capability and cycling stability between these H-Nb2O5 anodes in spite of significant discrepancy of SEI structure (e.g. thickness and chemical component). Further, it was observed using cryo-TEM that the discrete decoration of the individual inorganic particles (e.g. Li2O) and amorphous LiNxOy species in the direct SEI does not constitute a dense solid layer. From this study, we conclude a pore diffusion mechanism is dominated across the whole direct SEI layer with those porous organic components, which is extremely faster than the lithium ion knock-off diffusion in the inner inorganic components. Thus, the SEI structures have much less influence on the limitation of the lithium ion transport kinetics than those as commonly accepted if an inner dense inorganic layer is not formed. Our results provide a refreshed understanding on the fundamentals of the lithium ion transport in SEI, and will guide future design of battery materials for fast-charging.

Mesoporous Nanocarbon-Based PGM-Free Electrocatalysts Prepared with MgO-Template for Anion-Exchange Membrane Fuel Cell

Anion-exchange membrane fuel cells (AEMFCs) are receiving more and more attention as a viable alternative to proton-exchange membrane fuel cells, because they permit the use of precious metal-free electrocatalysts for oxygen reduction reaction (ORR), such as transition metal and nitrogen-doped carbon nanomaterials, containing MNx ORR-active sites.1 However, in addition to active sites, the structure of the catalyst support material is also essential to ensure efficient mass transfer in the catalyst layer, especially in AEMFCs where mass transport issues are caused by the higher loading that PGM-free catalysts require.2 Easily removable inorganic particles like MgO offer a sustainable alternative to silica-based templates to achieve optimal porosity. The catalyst materials can be created via a template-directed synthesis, by pyrolyzing a carbon precursor with MgO or other thermally unstable magnesium compounds like acetate or citrate. The precursors break down by heat-treatment to create MgO nanoparticles, which are subsequently dissolved using dilute acids such as HCl.3 Unlike with silica-based templates, scaling up the method is significantly easier and more sustainable since no corrosive chemicals like hydrofluoric acid are used in the process.Using HoneyolTM (a mixture of alkylresorcinols) as the carbon source and magnesium acetate as the template precursor, we demonstrate a straightforward MgO template-assisted approach for obtaining mesoporous nitrogen and transition metal co-doped nanocarbon catalysts for AEMFCs.4 The effect of the mass ratio of Honeyol to magnesium acetate on the porosity and electrocatalytic activity of the catalysts was studied. The addition of Mg acetate increases the surface area of the materials, the prepared materials are mostly mesoporous with a broad pore size distribution. The catalyst with the highest electrocatalytic activity toward the ORR was synthesized using a 2:1 mass ratio of Honeyol to Mg acetate. The bimetallic FeCoNC-MgOAc catalyst displayed the highest electrocatalytic activity surpassing the benchmark Pt/C catalyst, showing a E 1/2 value of -0.14 V vs. SCE in the RDE test. The catalyst demonstrated excellent stability, only a minor decay was observed after 15,000 potential cycles (ΔE 1/2 = 10 mV). In AEMFC as the cathode catalyst, FeCoNC-MgOAc reached a peak power density of 0.92 W cm-2 (Figure 1), more than twice higher as the untemplated FeCoNC catalyst and slightly surpassing the benchmark Pt/C (20 wt.%). The catalyst also displayed promising durability in AEMFC with a minor voltage degradation rate of 0.0017 V h–1 after 24 h. References Osmieri, L.; Pezzolato, L.; Specchia, S. Recent Trends on the Application of PGM-Free Catalysts at the Cathode of Anion Exchange Membrane Fuel Cells. Current Opinion in Electrochemistry 2018, 9, 240–256.Dekel, D. R. Review of Cell Performance in Anion Exchange Membrane Fuel Cells. Journal of Power Sources 2018, 375, 158–169.Morishita, T.; Tsumura, T.; Toyoda, M.; Przepiórski, J.; Morawski, A. W.; Konno, H.; Inagaki, M. A Review of the Control of Pore Structure in MgO-Templated Nanoporous Carbons. Carbon 2010, 48 (10), 2690–2707.Kisand, K.; Sarapuu, A.; Douglin, J. C.; Kikas, A.; Treshchalov, A.; Käärik, M.; Piirsoo, H.-M.; Paiste, P.; Aruväli, J.; Leis, J.; Kisand, V.; Tamm, A.; Dekel, D. R.; Tammeveski, K. Templated Nitrogen-, Iron-, and Cobalt-Doped Mesoporous Nanocarbon Derived from an Alkylresorcinol Mixture for Anion-Exchange Membrane Fuel Cell Application. ACS Catalysis 2022, 12 (22), 14050–14061. Figure 1

Functionalization of ZnAl-Layered Double Hydroxide with Ensulizole and Its Application as a UV-Protective Agent in a Transparent Polymer Coating.

In this study, we propose a promising photoprotective additive that combines the advantages of both organic UV absorbers and inorganic particles without compromising the properties of the paint material. This additive involves the intercalation of a well-known organic UV absorber, 2-phenylbenzimidazole-5-sulfonic acid (PBISA), into zinc-aluminum layered double hydroxide (ZnAl-LDH). Three ZnAl-LDH intercalates with PBISA were prepared using various methods based on either anion exchange or direct synthesis. The intercalates were characterized using powder X-ray diffraction, thermogravimetry, elemental analysis, and IR and UV-Vis spectroscopies. The composition and basal spacings of all three intercalates are very similar. An effective UV protection film was prepared when the ZnAl-PBISA-1 intercalate was incorporated into polyurethane-acrylate lacquer. The resultant UV protective film exhibited stability and uniform distribution of the intercalated fillers. Some minimal particle sedimentation and aggregation were observed on the cured film's underside, but did not compromise the films' UV protective properties. The prepared lacquers with intercalated fillers offer a viable solution for the surface modification of plastic products.

Mechanical Performance of Glass/Epoxy Composites Loaded with Silane-Treated Aluminum Hydroxide Fillers.

This study investigates the influence of silane-treated aluminum hydroxide on the mechanical performance of flame-retardant composites. These composites have potential applications for luggage bags, as a replacement for conventional plastics, offering more durability and lighter weight. Glass fabric was used as the reinforcement, while epoxy was used as the matrix material. To impart flame retardancy, aluminum hydroxide nanoparticles were used as fillers in different weight % age (5%, 10% and 15%). As these are inorganic particles and have compatibility issues with the matrix material, silane-coupling agents (Dynasylan® 6490 and Dynasylan Glymo) were used to treat these filler particles. Both the silane-coupling agents fraction used for treatment and the fillers fraction added to the composites were varied to determine the most optimum combination. The mechanical properties of the developed composites such as tensile, flexural, and short beam shear strength were investigated. The best results were exhibited by 10% aluminum hydroxide fillers treated with 1% (by weight) coupling agent (Dynasylan Glymo).

Novel multifuctional geomimetic soil conditioner based on multilayer hybrid composites of clay-paa-lignin: Synthesis and functional characterization

Soil conditioners are products of natural or synthetic origin that aim to improve the physical–chemical properties of poor or degraded soils. Recently, geomimicry has emerged as a novel strategy for obtaining geomimetic materials, which have been designed to imitate the structure and functions of soils, and potentially be used as soil conditioners, by improving their structure, increasing their capacity for water retention (WRC) and cation exchange capacity (CEC), restore the microbiota, etc. Thus, the development of hybrid composites has proven to be an appropriate strategy for obtaining novel materials that combine and improve the properties exhibited by their predecessors; being the systems based on clays and polymers capable of imitating the clay-humin-humic acid structures present in the soil particles and their properties. Therefore, the objective of this work was to develop new geomimetic soil conditioners based on multilayer hybrid composites, MHCs, of clay-PAA-lignin. For this, bentonite and kaolinite surfaces were chemically modified with trichlorovinylsilane to produce surface activation of the clay. Subsequently, chains of poly(acrylic acid), PAA, were inserted into the surface active clay by free radical reactions, in order to generate carboxylic acid groups on the surface. On the other hand, lignin was obtained from sugarcane bagasse by the basic delignification method and was incorporated into the polymeric matrix by urethanization with 4,4-methylenebis(phenyl isocyanate). By this method, lignin coatings on inorganic particles were obtained using urethane bonds. In addition, different clay-lignin ratios were evaluated. Finally, the material obtained was characterized by infrared spectroscopy, FEDS, nuclear magnetic resonance and thermogravimetric analysis. In addition, their WRC, CEC and bacterial viability properties were evaluated. The results showed that MHCs based on clay-PAA-Lignin can be obtained through the proposed methodology and mimic the structures and properties of soil. The WCR and CEC of the synthesized MHCs were lower than that of their predecessors, produced by the change in hydrophobicity of the materials. In addition, the developed MHCs showed a high microbial viability, >83 %, which suggests a high compatibility with the soil microbiota.

Preparation of polystyrene/EVA/CaCO3 microspheres using a novel one-pot method via a phase inversion emulsion process

The polymer/nano-inorganics composite microsphere possesses excellent application prospects, but it is difficult to resolve the problem of the aggregation of nano-inorganic particles in polymer and the affinity between inorganics and polymer matrix. In this study, the preparation and characterization of polystyrene (PS)/ethylene vinyl acetate copolymer (EVA)/CaCO3 microspheres fabricated via a novel phase inversion emulsion process are described. By this one-pot method, the PS/EVA/CaCO3 microspheres are obtained by firstly converting styrene monomer containing EVA and nano CaCO3 into droplets dispersed in water with help of emulsifiers and a following polymerization. Because the inorganic nanoparticles are ultrasonically dispersed in liquid monomer mixture before the polymerization, the aggregation of nano-inorganic particles could be prevented to a great extent. The EVA is designed to enhance toughness of polystyrene matrix and increase the affinity between polymer and inorganic particles. The morphological structure of PS/EVA/CaCO3 microspheres is that nano CaCO3 particles are embedded both in the interior and on the surface of the microspheres. The micro-sized PS/EVA/CaCO3 microspheres showed a significantly improved mechanical property and a better heat resistance. This technique also offers the possibility for fabricating many kinds of new and useful polymer/inorganic microspheres with tailored performance by using special monomers and inorganic particles.

Effect of inorganic fillers on the light transmission through traditional or flowable resin-matrix composites for restorative dentistry

ObjectivesThe aim of this in vitro study was to evaluate the light transmission through five different resin-matrix composites regarding the inorganic filler content.MethodsResin-matrix composite disc-shaped specimens were prepared on glass molds. Three traditional resin-matrix composites contained inorganic fillers at 74, 80, and 89 wt. % while two flowable composites revealed 60 and 62.5 wt. % inorganic fillers. Light transmission through the resin-matrix composites was assessed using a spectrophotometer with an integrated monochromator before and after light curing for 10, 20, or 40s. Elastic modulus and nanohardness were evaluated through nanoindentation’s tests, while Vicker’s hardness was measured by micro-hardness assessment. Chemical analyses were performed by FTIR and EDS, while microstructural analysis was conducted by optical microscopy and scanning electron microscopy. Data were evaluated using two-way ANOVA and Tukey’s test (p < 0.05).ResultsAfter polymerization, optical transmittance increased for all specimens above 650-nm wavelength irradiation since higher light exposure time leads to increased light transmittance. At 20- or 40-s irradiation, similar light transmittance was recorded for resin composites with 60, 62, 74, or 78–80 wt. % inorganic fillers. The lowest light transmittance was recorded for a resin-matrix composite reinforced with 89 wt. % inorganic fillers. Thus, the size of inorganic fillers ranged from nano- up to micro-scale dimensions and the high content of micro-scale inorganic particles can change the light pathway and decrease the light transmittance through the materials. At 850-nm wavelength, the average ratio between polymerized and non-polymerized specimens increased by 1.6 times for the resin composite with 89 wt. % fillers, while the composites with 60 wt. % fillers revealed an increased ratio by 3.5 times higher than that recorded at 600-nm wavelength. High mean values of elastic modulus, nano-hardness, and micro-hardness were recorded for the resin-matrix composites with the highest inorganic content.ConclusionsA high content of inorganic fillers at 89 wt.% decreased the light transmission through resin-matrix composites. However, certain types of fillers do not interfere on the light transmission, maintaining an optimal polymerization and the physical properties of the resin-matrix composites.Clinical significanceThe type and content of inorganic fillers in the chemical composition of resin-matrix composites do affect their polymerization mode. As a consequence, the clinical performance of resin-matrix composites can be compromised, leading to variable physical properties and degradation.Graphical

Flexible fibrous separator asymmetrically coated by silica and MXene for high performance lithium batteries with enhanced safety

Introducing inorganic particles into separator for lithium batteries has been proven to be a very effective and facile way to improve battery safety and performance. In this work, a composite separator (PBS-M-S) was developed via asymmetrically coating the conductive MXene particles and the nonconductive silica particles onto a biodegradable poly(butylene succinate) (PBS) fibrous membrane. Such a structure and material design was able to give the produced separator exceptional all-around properties. Specifically, the PBS-M-S separator displayed great flexibility with a 250% elongation at break, high temperature sensitivity with shutdown function at 120 °C, and thermal stability with flame retardancy. Moreover, the network constructed by PBS's micro/nano fibers and the electrolyte affinity of silica allowed the separator to maintain abundant electrolyte. This, combined with the incorporation of MXene, optimized the separator with high ionic conductivity (3.386 mS cm−1), lithium ion transference number (0.51) and lithium dendrite inhibition ability, which rendered the cell with outstanding cycling stability. Therefore, taking safety and battery performance into account, the as-prepared composite membrane could be a promising separator candidate for lithium ion batteries.

Nanoparticles in Medicine: Current Status in Cancer Treatment.

Cancer is still a leading cause of deaths worldwide, especially due to those cases diagnosed at late stages with metastases that are still considered untreatable and are managed in such a way that a lengthy chronic state is achieved. Nanotechnology has been acknowledged as one possible solution to improve existing cancer treatments, but also as an innovative approach to developing new therapeutic solutions that will lower systemic toxicity and increase targeted action on tumors and metastatic tumor cells. In particular, the nanoparticles studied in the context of cancer treatment include organic and inorganic particles whose role may often be expanded into diagnostic applications. Some of the best studied nanoparticles include metallic gold and silver nanoparticles, quantum dots, polymeric nanoparticles, carbon nanotubes and graphene, with diverse mechanisms of action such as, for example, the increased induction of reactive oxygen species, increased cellular uptake and functionalization properties for improved targeted delivery. Recently, novel nanoparticles for improved cancer cell targeting also include nanobubbles, which have already demonstrated increased localization of anticancer molecules in tumor tissues. In this review, we will accordingly present and discuss state-of-the-art nanoparticles and nano-formulations for cancer treatment and limitations for their application in a clinical setting.

Enabling high rate capability and stability all-solid-state batteries via cationic surfactant modification of composite electrolyte

The garnet-type solid electrolyte Li6.4La3Zr1.4Ta0.6O12 (LLZTO) was modified with a cationic surfactant Cetyltrimethylammonium Bromide (CTAB) to improve the dispersion of LLZTO inorganic particles in Poly (ethylene oxide) (PEO) electrolyte (PEO-LLZTO@CTAB) by a liquid phase casting method. During fabrication, the cationic modifier CTAB is uniformly adsorbed on the surface of LLZTO particles, which can effectively reduce their surface energy and lead to a thin CTAB surface coating layer. This fabricated PEO-LLZTO@CTAB can avoid the aggregation of LLZTO particles in the composite solid-state electrolyte (CSSE) and improve the interfacial contact at the PEO/LLZTO interface, thus reducing the overall resistance of PEO-LLZTO@CTAB/Li half-cell and inhibiting the dendrite growth during cycling. The all-solid-state batteries (ASSBs) with LiFePO4 (LFP) as the cathode, PEO-LLZTO@CTAB as the electrolyte and Li as the anode exhibit a high initial discharge capacity of 146.6 mAh-g−1, excellent rate performance and high-capacity retention of 91.0 % after 300 cycles at 0.2 C multiplier and 60 °C within the voltage range of 2.7–4.0 V.

Bioinspired self-healing injectable nanocomposite hydrogels based on oxidized dextran and gelatin for growth-factor-free bone regeneration

Hydrogels with great biocompatibility, biodegradability, and mechanical properties, combined with osteoconductivity, osteoinductivity, and osteointegration as biomaterials for bone regeneration without adding exogenous growth factors and cells are highly appealing but challenging. Here, inspired by organic-inorganic analogues of natural bone tissue and the adhesion chemistry of mussels, nanocomposite hydrogels with self-healing, injectable, adhesive, antioxidant, and osteoinductive properties (termed GO-PHA-CPs) were constructed by Schiff base cross-linking between dopamine-modified gelatin (Gel-DA) and oxidized dextran (ODex). Furthermore, the hydrogel network was enhanced by the introduction of polydopamine-functionalized nanohydroxyapatite (PHA) by improving the interfacial compatibility between the rigid inorganic particles and the flexible hydrogel matrix. Bioactive cod peptides (CPs) with osteogenic activity from Atlantic cod were further incorporated into the nanocomposite hydrogel. As a result, the multicomponent nanocomposite hydrogel favored the adhesion and spreading of MC3T3-E1 cells. The increased ALP activity suggested that GO-PHA-CPs hydrogels contributed to the osteogenic differentiation of MC3T3-E1 cells. The suitability of GO-PHA-CPs hydrogels for enhancing bone regeneration in vivo was further confirmed by the rat femoral defect model. Our results indicate that the multifunctional GO-PHA-CPs nanocomposite hydrogels without growth factors are a promising and effective candidate material for bone regeneration.

Interfacial mechanism and inactivation efficiency of bacteriophage MS2 by ozone in high turbidity and algal-laden water resource

With the onset of the COVID-19 epidemic and the measures implemented to curb the spread of the SARS-CoV-2 virus, there has been increasing attention on safe drinking water and waterborne viruses during water treatment processes. In this study, we investigate the impact of solution chemistry, including ionic strength (Na+ or Ca2+) pH, and natural organic matter (NOM), on the efficiency of MS2 bacteriophage inactivation by ozone in the presence of inorganic and organic particles (kaolinite (KAO) and microcystis aeruginosa (MA), respectively). The study results demonstrate that KAO has been found to adsorb MS2, but it does not significantly affect the inactivation of MS2 by ozone. In contrast, the inactivation of MS2 increased at low MA concentrations ranging from 105 to 106 cells/L due to MS2 dispersion, but decreased at higher concentrations ranging from 107 to 108 cells/L. The monovalent Na+ ion solutions (~200 mmol/L) maintain MS2 stability and dispersion irrespective of the presence of particles, and did not affect inactivation. Additionally, MS2 aggregates in divalent Ca2+ solutions, resulting in reduced inactivation with or without particles present. Increasing the solution's pH had a negative impact on inactivation, leading to ozone reduction and weakening of the inactivation. However, the presence of NOM poses a significant risk to the safety of drinking water by reducing MS2 inactivation.

Settling velocities of coarse organic solids

The settling velocity of a particle is an integral parameter in stormwater modeling and design. The settling velocity can be used to predict the fate and transport of stormwater particles and if the particles contribute to nutrient loading in a watershed. Prediction of settling velocity for inorganic particles is generally well-researched and well-understood. Organic particles tend to vary widely in their physical properties and there are currently no set standards or empirical equations for estimating the settling velocity of organic particles. This paper presents data from tree leaves and seeds settling velocity experiments to better understand how organic particles settle in the context of settling velocity equations such as the one developed by Ferguson and Church. Analysis of the collected data showed that the second of the two drag coefficients (C2) used in the Ferguson and Church Equation was sensitive to particle type and shape. By averaging C2 by particle type and species, there was a correlation between the observed settling velocity and the settling velocity predicted by the Ferguson and Church Equation (R2 = 0.83). With these results, stormwater modelers and designers are equipped with a better understanding of how to represent common organic particles in terms of settling velocity. Additional research on a wider variety of organic particle types and species would expand on the dataset presented here.

Polymer Nanoparticles Applied in the CMP (Chemical Mechanical Polishing) Process of Chip Wafers for Defect Improvement and Polishing Removal Rate Response.

Chemical mechanical planarization (CMP) is a wafer-surface-polishing planarization technique based on a wet procedure that combines chemical and mechanical forces to fully flatten materials for semiconductors to be mounted on the wafer surface. The achievement of devices of a small nano-size with few defects and good wafer yields is essential in enabling IC chip manufacturers to enhance their profits and become more competitive. The CMP process is applied to produce many IC generations of nanometer node, or those of even narrower line widths, for a better performance and manufacturing feasibility. Slurry is a necessary supply for CMP. The most critical component in slurry is an abrasive particle which affects the removal rates, uniformity, defects, and removal selectivity for the materials on the wafer surface. The polishing abrasive is the source of mechanical force. Conventional CMP abrasives consist of colloidal silica, fume silica or other inorganic polishing particles in the slurries. We were the first to systematically study nanoparticles of the polymer type applied in CMP, and to compare traditional inorganic and polymer nanoparticles in terms of polishing performance. In particular, the polymer nanoparticle size, shape, solid content dosing ratio, and molecular types were examined. The polishing performance was measured for the polishing removal rates, total defect counts, and uniformity. We found that the polymer nanoparticles significantly improved the total defect counts and uniformity, although the removal rates were lower than the rates obtained using inorganic nanoparticles. However, the lower removal rates of the polymer nanoparticles are acceptable due to the thinner film materials used for smaller IC device nodes, which may be below 10 nm. We also found that the physical properties of polymer nanoparticles, in terms of their size, shape, and different types of copolymer molecules, cause differences in the polishing performance. Meanwhile, we used statistical analysis software to analyze the data on the polishing removal rates and defect counts. This method helps to determine the most suitable polymer nanoparticle for use as a slurry abrasive, and improves the reliability trends for defect counts.

Investigation of solid particle erosion‐related failures in once‐through steam generators (OTSGs) in oil sands in‐situ production: The limitations of the API RP 14E guideline in OTSG design or operational decision‐making

AbstractThe required steam for steam‐assisted gravity drainage (SAGD) oil sands operations is generated using a once‐through steam generator (OTSG) that is fed with relatively poor quality process water. Industries have reported possible solid particle erosion‐related failure in the OTSG boiler tubes because of the transport of precipitated dense inorganic particles. However, the presence of other damage mechanisms, e.g. corrosion, flow accelerated corrosion (FAC), often masks the evidence of erosive wear. Also, industries set an upper limit operating velocity for the OTSG using the API RP 14E guideline, which provides no quantitative erosion rates to determine an operating envelope. This study presents a computational fluid dynamics (CFD) analysis of erosion damage in a SAGD OTSG boiler tube. The results revealed that API RP 14E may not be an effective decision‐making tool for operating the OTSG system. For example, a 10% increase in velocity, even at conditions below the API RP 14E threshold, showed a decrease in the failure time of the boiler tubes by 40%–50%.

Modeling the swelling kinetics of preformed particle gels coated with a silicate layer

This study presented an organic–inorganic hybrid preformed particle gels (PPG) by coating a tetramethyl orthosilicate layer on acrylamide-based PPG to control the swelling rate of PPG in simulated aqueous media. The coated silicate layer on the PPG delayed the equilibrium swelling time by several hours. Furthermore, jump boundary conditions at interfaces were applied to develop a mathematical model for the swelling kinetics of hybrid PPG with three distinct regions and three moving boundaries. The proposed model results showed that the diffusion coefficient of distilled water and saltwater in the coated layer and its thickness control the swelling process of these hybrid gel particles. Furthermore, the error percentages of predictive results by the proposed mathematical model for experimental swelling kinetic measurements of coated PPG were less than 5.25%. The experimental results also showed that the silicate layer controlled PPG swelling kinetics and improved hybrid PPG's strength and thermal stability.

Application of Synthetic Biology Approaches to High-Yield Production of Mycosporine-like Amino Acids

Ultraviolet (UV) radiation reaching the Earth’s surface is a major societal concern, and therefore, there is a significant consumer demand for cosmetics formulated to mitigate the harmful effects of UV radiation. Synthetic sunscreens being formulated to block UV penetration include inorganic metal oxide particles and organic filters. Lately, organic UV-absorbing compounds are manufactured from non-renewable petrochemicals and, as a result, there is a need to develop a sustainable manufacturing process for efficient, high-level production of a naturally occurring group of UV-absorbing compounds, namely mycosporine-like amino acids (MAAs), for use as a sunscreen additive to skincare products. Currently, the commercial production of MAAs for use in sunscreens is not a viable proposition due to the low yield and the lack of fermentation technology associated with native MAA-producing organisms. This review summarizes the biochemical properties of MAAs, the biosynthetic gene clusters and transcriptional regulations, the associated carbon-flux-driving processes, and the host selection and biosynthetic strategies, with the aim to expand our understanding on engineering suitable cyanobacteria for cost-effective production of natural sunscreens in future practices.

Omniphobic coatings based on functional acrylic polymer

Omniphobic coatings were prepared on flat surfaces using a functional acrylic polymer and common micron sized inorganic particles by a simple spray application technique. This coating comprises of a blend of functional acrylic polysiloxane polymer and liquid epoxy resin as a primer base coat followed by spray application of a mixture of organosilanes and inorganic microparticles. The microparticles are fillers commonly used in the paint and coating industry. The resulting surface has the desired surface energy and surface morphology to enable liquid repellency with contact angles of ∼150° for water and 142° for diiodomethane with a roll off angle of <5°. Scanning Electron Microscopic (SEM) and Atomic Force Microscopy (AFM) analysis were performed to study surface morphology. This coating can be applied on large areas and can be cured under ambient conditions. This omniphobic coating is robust, free of nanoparticles and can be used for potential applications in the field of self-cleaning coatings, anti-microbial coatings, and easy cleaning coatings.

A Coupled Electro-Mechanical Homogenization-Based Model for PVDF-Based Piezo-Composites Considering α → β Phase Transition and Interfacial Damage.

Polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is a piezoelectric semi-crystalline polymer whose electro-mechanical properties may be modulated via strain-induced α → β phase transition and the incorporation of polarized inorganic particles. The present work focuses on the constitutive representation of PVDF-based piezo-composites developed within the continuum-based micromechanical framework and considering the combined effects of particle reinforcement, α → β phase transition, and debonding along the interface between the PVDF matrix and the particles under increasing deformation. The micromechanics-based model is applied to available experimental data of PVDF filled with various concentrations of barium titanate (BaTiO3) particles. After its identification and predictability verification, the model is used to provide a better understanding of the separate and synergistic effects of BaTiO3 particle reinforcement and the micromechanical deformation processes on the electro-mechanical properties of PVDF-based piezo-composites.

Organic Matrix Derived from Host-Microbe Interplay Contributes to Pathological Renal Biomineralization.

Matrix stones are a rare form of kidney stones. They feature a high percentage of hydrogel-like organic matter, and their formation is closely associated with urinary tract infections. Herein, comprehensive materials and biochemical approaches were taken to map the organic-inorganic interface and gather insights into the host-microbe interplay in pathological renal biomineralization. Surgically extracted soft and slimy matrix stones were examined using micro-X-ray computed tomography and various microspectroscopy techniques. Higher-mineral-density laminae were positive for calcium-bound Alizarin red. Lower-mineral-density laminae revealed periodic acid-Schiff-positive organic filamentous networks of varied thickness. These organic filamentous networks, which featured a high polysaccharide content, were enriched with zinc, carbon, and sulfur elements. Neutrophil extracellular traps (NETs) along with immune response-related proteins, including calprotectin, myeloperoxidase, CD63, and CD86, also were identified in the filamentous networks. Expressions of NETs and upregulation of polysaccharide-rich mucin secretion are proposed as a part of the host immune defense to "trap" pathogens. These host-microbe derived organic matrices can facilitate heterogeneous nucleation and precipitation of inorganic particulates, resulting in macroscale aggregates known as "matrix stones". These insights into the plausible aggregation of constituents through host-microbe interplay underscore the unique "double-edged sword" effect of the host immune response to pathogens and the resulting renal biominerals.