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Abstract: The synthesis of mono-dispersed γ-Fe2O3 nanoparticles by mechanochemical processing was demonstrated for the first time, via the solid-state exchange reaction Fe2(SO4)3 +3Na2CO3 →Fe2(CO3)3 +3Na2SO4 →Fe2O3 +3Na2SO4 +3CO2(g) and subsequent heat treatment at 673K. The nanoparticles had a volume-weighted mean diameter of 6nm and a narrow size distribution with the standard deviation of 3nm. The particles showed a superparamagnetic nature with the superparamagnetic blocking temperature of 56.6K. The anisotropy constant was 6.0×106 erg/cm3, two orders of magnitude larger than the magnetocrystalline anisotropy constant of bulk γ-Fe2O3. The detailed analysis of the magnetic properties indicated that the γ-Fe2O3 nanoparticles had a core–shell structure, consisting of a ferrimagnetic core of ∼4nm in diameter having a collinear spin configuration and a magnetically disordered shell of ∼1.2nm in thickness. [Copyright &y& Elsevier]

ZnO quantum dots were synthesized via a low-temperature solvothermal process without using surfactants. Heat treatment of ZnCl2 and NaOH solutions in tetra-ethylene glycol at 140°C led to the formation of spherical ZnO nanoparticles consisting of the aggregates of uniform-sized quantum dots. The particle size and morphology were characterized using transmission electron microscopy, dynamic light scattering, X-ray diffraction, and Brunauer–Emmett–Teller gas absorption measurements. It was found that the quantum dots in the particles were single crystals of ZnO of ∼5 nm in diameter having the wurtzite structure. The quantum dots showed quantum size effects even in the agglomerated form. The growth mechanism of this new type of ZnO nanoparticles is proposed. [ABSTRACT FROM AUTHOR]

Investigates the synthesis of ultrafine cerium dioxide powders using mechanochemical reaction and subsequent calcination. Induction of a solid-state displacement reaction during milling; Formation of cerium dioxide nanoparticles in the sodium chloride matrix; Control of the particle size.

Biomass-derived materials are put forward as eco-friendly alternatives to design heterogeneous catalysts. To contribute in this field, we explored the potential of mesoporous biogenic silica (RH-Silica) obtained from lignocellulosic waste, in particular from rice husk, as an inorganic support to prepare heterogenized iron oxide-based catalysts. Mechanochemistry, considered as a green and sustainable technique, was employed to synthetize iron oxide nanoparticles in pure hematite phase onto the biosilica (α-Fe2O3/RH-Silica), making this material a good candidate to perform catalyzed organic reactions. The obtained material was characterized by different techniques, and its catalytic activity was tested in the selective oxidation of styrene under microwave irradiation. α-Fe2O3/RH-Silica displayed a good catalytic performance, achieving a conversion of 45% under optimized conditions, and more importantly, with a total selectivity to benzaldehyde. Furthermore, a good reusability was achieved without decreasing its activity after multiple catalytic cycles. This work represents a good example of using sustainable approaches and green materials as alternatives to conventional methods in the production of high-added value products. [ABSTRACT FROM AUTHOR]

The raising occurrence of antibiotics in the global water bodies has received the emerging concern due to their potential threats of generating the antibiotic-resistive and genotoxic effects into humans and aquatic species. In this direction, the solar energy assisted photocatalytic technique offers a promising solution to address such emerging concern and paves ways for the complete degradation of antibiotics with the generation of less or non-toxic by-products. Particularly, the designing of hybrid photocatalyticcomposite materials has been found to show higher antibiotics degradation efficiencies. As the hybrid photocatalysts are found as the systems with ideal characteristic properties such as superior structural, surface and interfacial properties, they offer enhanced photoabsorbance, charge-separation, -transfer, redox properties, photostability and easy recovery. In this context, this review study presents an overview on the recent developments in the designing of various hybrid photocatalytic systems and their efficiency towards the degradation of various emerging antibiotic pharmaceutical contaminants in water environments. [ABSTRACT FROM AUTHOR]

Recombinant Bacillus subtilis lipase was immobilised on magnetic nanoparticles by a facile covalent method and applied to fish oil hydrolysis. High loading of enzyme to the functionalised nanoparticle was achieved with a protein binding efficiency of 95%. Structural changes of the confined enzyme on the surface of the nanoparticles was investigated using transmission electron microscopy and spectroscopic techniques (attenuated total reflectance-Fourier transform infrared and circular dichroism). The biocatalytic potential of immobilised lipase was compared with that of free enzyme and biochemically characterised with respect to different parameters such as pH, temperature, substrate concentrations and substrate specificity. The thermal stability of functionalised nanoparticle bound enzyme was doubled that of free enzyme. Immobilised lipase retained more than 50% of its initial biocatalytic activity after recyclability for twenty cycles. The ability to the immobilised thermostable lipase to concentrate omega-3 fatty acids from fish oil was investigated. Using synthetic substrate, the immobilised enzyme showed 1.5 times higher selectivity for docosahexaenoic acid (DHA), and retained the same degree of selectivity for eicosapentaenoic acid (EPA), when compared to the free enzyme. [ABSTRACT FROM AUTHOR]

Impurity doping is one of the common approaches to enhance the photoactivity of semiconductor nanomaterials by increasing photon-capture efficiency in the visible light range. However, many studies on the doping effects have produced inconclusive and conflicting results. There are some misleading assumptions and errors that are frequently made in the data interpretation, which can lead to inconsistent results about the doping effects on photocatalysis. One of them is the determination of the location of dopants. Even using advanced analytical techniques, it is still challenging to distinguish between bulk modification and surface modification. The paper provides a case study of transition-metal-doped ZnO nanoparticles, whereby demonstrating common pitfalls in the interpretation of the results of widely-used analytical methods in detail, and discussing the importance of using a combination of many characterization techniques to correctly determine the location of added impurities, for elucidating the influence of metal doping on the photocatalytic activities of semiconductor nanoparticles. [ABSTRACT FROM AUTHOR]

The present study demonstrated that chitin-based nanofibers (CNFs) trigger the chitinase genes (PGIP1 and CaChi2), while elevating salicylic acid that can protect plants against pathogens. Cross-talk between this genetic induction and salicylic-acid-mediated immune response was also observed, which may arm a plant against multiple pathovars. Crab and mushroom based CNFs were synthesized by electrospinning and ball milling techniques. Plants (mung bean, Vigna radiata) (pepper, Capsicum annuum) were pre-inoculated with CNFs and treated with the pathogens Scrolotium rolfsii for pepper and Macrophomina phaseolina for mung bean and shrimp-based CNFs were used as a control. Treated plants had elevated levels of chitinase genes in response to CNFs at inoculation concentrations <10 mg/mL both in soil and media, to protect them against the pathogenic fungal disease. After 24 h of exposure to the pathogens, qRT-PCR showed genes class II chitinase gene (CaChi2) and polygalacturonase inhibitor protein 1 (PGIP1) to be up-regulated in both root and shoot at 0.1 and 1 mg/mL of inoculation, respectively. The ball milled mushroom CNFs were sufficient to trigger the membrane based enzymes with less diameter (≥15 nm) to be most efficient versus others. In vitro analysis showed IC 50 of ball milled mushroom CNFs to be most efficient in limiting the growth of fungal biomass. Further trigger-like effects were prominent in reducing pathogenic fungal spread in both species. [ABSTRACT FROM AUTHOR]

Engineering of highly performing nanomaterials, capable of rapid detection of trace concentrations of gas molecules at room temperature, is key to the development of the next generation of miniaturized chemical sensors. Here, a highly performing nanoheterojunctions layout is presented for the rapid room‐temperature chemical sensing of volatile organic compounds down to ten particles per billion concentrations. The layout consists of a 3D network of nickel oxide–zinc oxide (NiO–ZnO) p–n semiconductors with grain size of ≈20 nm nanometers and a porosity of ≈98%. Notably, it is observed that the formation of the p–n heterojunctions by decoration of a ZnO nanoparticle networks with NiO increases the sensor response by more than four times while improving the lower limit of detection. Under solar light irradiation, the optimal NiO–ZnO nanoheterojunction networks demonstrate a strong and selective room‐temperature response to two important volatile organic compounds utilized for breath analysis, namely acetone and ethanol. Furthermore, these NiO–ZnO nanoheterojunctions show an inverse response to acetone from that observed for all others reducing gas molecules (i.e., ethanol, propane, and ethylbenzene). It is believed that these novel insights of the optoelectrochemical properties of ultraporous nanoheterojunction networks provide guidelines for the future design of low‐power solid‐state chemical sensors. 3D ultraporous network of NiO–ZnO is constructed for the detection of volatile organic compounds at room temperature under solar irradiation. The formation of p–n nanoheterojunctions not only increases the sensor response, but also improves the lower limit of detection, which provides guideline for the design of low‐power solid‐state chemical sensors in the near future. [ABSTRACT FROM AUTHOR]

MnO 2 nanorods were synthesized by mechanochemical processing with subsequent heat treatment and their photocatalytic activity was studied on the decolourization of aqueous solution of Rhodamine B at different pH levels. A solid state redox reaction 2KMnO 4 + MnCl 2 → 3MnO 2 + 2KCl + O 2 was activated during mechanical milling. Excess KCl salt was added in the starting powder mixture to prevent agglomeration of MnO 2 nanoparticles. The milling resulted in the production of amorphous MnO 2 nanoparticles with a high surface area of 204 m 2 g −1 . Crystalline MnO 2 nanorods of diameters about 15–20 nm were produced by heating the as-milled powder at 350 °C for 1 h in air. Amorphous MnO 2 nanoparticles showed higher degradation rate of Rhodamine B than crystalline MnO 2 nanorods under simulated sunlight. The degradation rate was higher under acidic conditions. This work demonstrates the potential for cost effective, green and scalable synthesis of MnO 2 nano-catalysts for environmental applications. [ABSTRACT FROM AUTHOR]

A palygorskite-iron oxide nanocomposite (Pal-IO) was synthesized in situ by embedding magnetite into the palygorskite structure through co-precipitation method. The physico-chemical characteristics of Pal-IO and their pristine components were examined through various spectroscopic and micro-analytical techniques. Batch adsorption experiments were conducted to evaluate the performance of Pal-IO in removing Pb(II) from aqueous solution. The surface morphology, magnetic recyclability and adsorption efficiency of regenerated Pal-IO using desorbing agents HCl (Pal-IO-HCl) and ethylenediaminetetraacetic acid disodium salt (EDTA-Na 2 ) (Pal-IO-EDTA) were compared. The nanocomposite showed a superparamagnetic property (magnetic susceptibility: 20.2 emu g −1 ) with higher specific surface area (99.8 m 2 g −1 ) than the pristine palygorskite (49.4 m 2 g −1 ) and iron oxide (72.6 m 2 g −1 ). Pal-IO showed a maximum Pb(II) adsorption capacity of 26.6 mg g −1 (experimental condition: 5 g L −1 adsorbent loading, 150 agitations min −1 , initial Pb(II) concentration from 20 to 500 mg L −1 , at 25 °C) with easy separation of the spent adsorbent. The adsorption data best fitted to the Langmuir isotherm model (R 2 = 0.9995) and pseudo-second order kinetic model (R 2 = 0.9945). Pb(II) desorption using EDTA as the complexing agent produced no disaggregation of Pal-IO crystal bundles, and was able to preserve the composite's magnetic recyclability. Pal-IO-EDTA exhibited almost 64% removal capacity after three cycles of regeneration and preserved the nanocomposite's structural integrity and magnetic properties (15.6 emu g −1 ). The nanocomposite holds advantages as a sustainable material (easily separable and recyclable) for potential application in purifying heavy metal contaminated wastewaters. [ABSTRACT FROM AUTHOR]

Brick shaped mineral deposits or crystals are found in the shell of semi-domestic silk cocoon of Antheraea assamensis (A. assamensis). Effective removal and recovery of these crystals are important to understand their roles in the cocoon's protective function towards pupae. In this study, chemical and physical (ultrasonication) demineralisation methods were investigated for A. assamensis. It was found that the physical demineralisation method could effectively separate crystals without changing their shape and size and not effecting other components of the silk cocoon. The efficient recovery of the crystals, without any change in their chemical composition was confirmed based on FTIR, XRD and EDX techniques. Chemical demineralisation method was optimised and performed under milder conditions than reported in the past. It helped reeling of silk without much loss of strength or natural colour of silk fibre. [ABSTRACT FROM AUTHOR]

The spread of viral and bacterial pathogens mediated by contact with surfaces is a leading cause of infection worldwide. COVID‐19 and the continuous rise of deaths associated with antibiotic‐resistant bacteria highlight the need to impede surface‐mediated transmission. A sprayable coating with an intrinsic ability to resist the uptake of bacteria and viruses from surfaces and droplets, such as those generated by sneezing or coughing, is reported. The coating also provides an effective microbicidal functionality against bacteria, providing a dual barrier against pathogen uptake and transmission. This antimicrobial functionality is fully preserved following scratching and other induced damage to its surface or 9 days of submersion in a highly concentrated suspension of bacteria. The coatings also register an 11‐fold decrease in viral contamination compared to the noncoated surfaces. [ABSTRACT FROM AUTHOR]

Abstract: Oxygen plasma treatment of TiO2 films has been used to improve the efficiency of dye sensitized solar cells. Both a commercial TiO2 sample and a TiO2 thin film synthesized by a sol-gel technique were treated using a custom built inductively coupled plasma apparatus. X-ray photoelectron spectroscopy revealed that oxygen-plasma treatment increased the number of oxygen functional groups (hydroxyl groups) and introduced some Ti3+ species on the surface of TiO2. A sample solar cell with plasma treated TiO2 showed an overall solar-to-electricity conversion efficiency of 4.3%, about a 13% increase over untreated TiO2. The photon conversion efficiency for the plasma treated TiO2 was 34% higher than untreated TiO2. This enhanced cell-performance is partly due to increased dye adsorption from an increase in surface oxygen functional groups and also may be partly due to Ti3+ states on the surface of TiO2. [Copyright &y& Elsevier]

Abstract: The objective of the present work was to develop a thermostable β-glucosidase through immobilization on a nanoscale carrier for potential application in biofuel production. β-Glucosidase (BGL) from Aspergillus niger was immobilized to functionalized magnetic nanoparticles by covalent binding. Immobilized nanoparticles showed 93% immobilization binding. Immobilized and free BGL were characterized using Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) techniques. Free and immobilized enzyme exhibited different pH-optima at pH 4.0 and 6.0, respectively, but had the same temperature optima at 60°C. Michaelis constant (K M) was 3.5 and 4.3mM for free and immobilized BGL. Thermal stability of the immobilized enzyme was enhanced at 70°C. The immobilized nanoparticle–enzyme conjugate retained more than 50% enzyme activity up to the 16th cycle. Maximum glucose synthesis from cellobiose hydrolysis by immobilized BGL was achieved at 16h. [Copyright &y& Elsevier]

Abstract: Core–shell structured polystyrene (PS)-Fe3O4-graphene oxide (GO) composite nanoparticles were synthesized by sequentially depositing Fe3O4 nanoparticles and GO sheets onto the carboxyl functionalized PS template nanoparticles through electrostatic interactions. Morphologies of the composite nanoparticles were studied by both scanning electron microscopy and transmission electron microscopy, while their structures and chemical components were examined via Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The data confirmed the coexistence of PS, Fe3O4 and GO with a core–shell structure in the composite. The obtained PS@Fe3O4@GO nanoparticles possess excellent magnetic responsivity to externally applied magnetic field and can also form stable dispersion upon the removal of magnetic field. The study on the loading capacity of model molecule Rhodamine B (RhB) indicated the possibilities of using PS@Fe3O4@GO nanoparticles in targeted drug delivery applications. [Copyright &y& Elsevier]

ZnO nanoparticles doped with up to 5 at% of Co and Mn were prepared using a co-precipitation method. The location of dopant ions and the effect of doping on the photocatalytic activity were investigated. The crystal structure of nanoparticles and local atomic arrangements around dopant ions were analyzed by X-ray absorption spectroscopy. The results showed that the Co ions substituted the Zn ions in the ZnO wurtzite phase structure and induced lattice shrinkage, while Mn ions were not completely incorporated in the crystal lattice. The photocatalytic activity under simulated sunlight was characterized by the decomposition of Rhodamine B dye molecules. It was revealed that Co-doping strongly reduced the photocatalytic activity but Mn-doping showed a weaker effect on the reduction of the photoactivity. [ABSTRACT FROM AUTHOR]

Abstract: The location of dopant ions and the effect of doping level on the photocatalytic activity have been investigated on Co-doped ZnO nanopowders. A co-precipitation method was used to prepare ZnO nanoparticles of <50nm in diameter doped with up to 5at% of Co. The crystal structure of nanoparticles and local atomic arrangements around dopant ions were analysed by X-ray diffraction and extended X-ray absorption fine structure spectroscopy using synchrotron radiation. The results showed the Co ions substituted the Zn ions in ZnO crystal lattice and induced lattice shrinkage. The photocatalytic activity under simulated sunlight irradiation was characterised by the decomposition of Rhodamine B dye molecules, which revealed the successful reduction of photocatalytic activity by Co-doping. [Copyright &y& Elsevier]

Abstract: The successful use of nanoparticulate ZnO in applications such as UV-screening agents or photocatalyst for the destruction of chemical waste requires the development of techniques for controlling its photocatalytic activity. In this study, we have investigated transition metal doping as a means of achieving this goal. Powders of ZnO, Mn x Zn1−x O, and Co x Zn1−x O were synthesised by a three-stage process consisting of high-energy mechanical milling, heat treatment, and washing. The photocatalytic activity of these powders was evaluated using the spin-trapping technique with electron paramagnetic resonance spectroscopy. It was found that the photocatalytic activity of Co x Zn1−x O progressively decreased with the doping level. In contrast, the activity of Mn x Zn1−x O initially increased with doping up to a level of 2mol% and thereafter declined. These results demonstrate that doping with transition metal oxides can be used to tailor the photocatalytic properties of nanoparticulate ZnO. [Copyright &y& Elsevier]

Abstract: In this study, mechanochemical reaction systems with H2WO4 as a precursor were investigated for the synthesis of nanoparticulate powders of WO3, ZnWO4, and dual-phase (ZnWO4) x (ZnO)1–x . The objective was to establish whether mechanochemical processing can be used to manufacture high activity photocatalysts in the ZnO–WO3 system. Milling and heat treatment of H2WO4 +12NaCl was found to result in the formation of irregularly shaped platelets of a sodium tungstate rather than nanoparticles of WO3. Powders of single-phase ZnWO4 and dual-phase (ZnWO4) x (ZnO)1–x were successfully synthesised by incorporating H2WO4 into the ZnCl2 +Na2CO3 +4NaCl reactant mixture. The photocatalytic activity of these powders was evaluated using the spin-trapping technique with electron paramagnetic resonance spectroscopy. It was found that the photocatalytic activity decreased with the ZnWO4 content. This decrease in activity was attributed to the larger average particle size of the ZnWO4 component compared to the ZnO, which reduced the surface area available for interfacial transfer of the photogenerated charge carriers. [Copyright &y& Elsevier]

Abstract: Nanoparticulate TiO2 is of interest for a variety of technological applications, including optically transparent UV-filters and photocatalysts for the destruction of chemical waste. The successful use of nanoparticulate TiO2 in such applications requires an understanding of how the synthesis conditions effect the optical and photocatalytic properties. In this study, we have investigated the effect of heat treatment temperature on the properties of nanoparticulate TiO2 powders that were synthesised by solid-state chemical reaction of anhydrous TiOSO4 with Na2CO3. It was found that the photocatalytic activity increased with the heat treatment temperature up to a maximum at 600°C and thereafter declined. In contrast, the optical transparency decreased monotonically with the heat treatment temperature. These results indicate that solid-state chemical reaction can be used to prepare powders of nanoparticulate TiO2 with properties that are optimised for use as either optically transparent UV-filters or photocatalysts. [Copyright &y& Elsevier]

[Display omitted] Development of polymeric magnetic adsorbents is a promising approach to obtain efficient treatment of contaminated water. However, the synthesis of magnetic composites involving multiple components frequently involves tedious preparation steps. In the present study, a magnetic chitosan-palygorskite (MCP) nanocomposite was prepared through a straight-forward one pot synthesis approach to evaluate its lead (Pb2+) removal capacity from aqueous solution. The nano-architectural and physicochemical properties of the newly-developed MCP composite were described via micro- and nano-morphological analyses, and crystallinity, surface porosity and magnetic susceptibility measurements. The MCP nanocomposite was capable to remove up to 58.5 mg Pb2+ g−1 of MCP from water with a good agreement of experimental data to the Langmuir isotherm model (R2 = 0.98). The Pb2+ adsorption process on MCP was a multistep diffusion-controlled phenomenon evidenced by the well-fitting of kinetic adsorption data to the intra-particle diffusion model (R2 = 0.96). Thermodynamic analysis suggested that the adsorption process at low Pb2+ concentration was controlled by chemisorption, whereas that at high Pb2+ concentration was dominated by physical adsorption. X-ray photoelectron and Fourier transform infrared spectroscopy results suggested that the Pb adsorption on MCP was governed by surface complexation and chemical reduction mechanisms. During regeneration, the MCP retained 82% Pb2+ adsorption capacity following four adsorption–desorption cycles with ease to recover the adsorbent using its strong magnetic property. These findings highlight the enhanced structural properties of the easily-prepared nanocomposite which holds outstanding potential to be used as an inexpensive and green adsorbent for remediating Pb2+ contaminated water. [ABSTRACT FROM AUTHOR]

Geometrical structuring of monolithic metal‐organic frameworks (MOFs) components is required for their practical implementation in many areas, including electronic devices, gas storage/separation, catalysis, energy storage as well as bio‐medical applications. Despite progress in structuring MOFs, an approach for the precise patterning of MOF functional geometries in the millimeter‐ to micro‐meter depth is lacking. Here, a facile and flexible concept for the microfabrication of complex MOF patterns on large surfaces is reported. The method relies on the engineering of easily‐writable sheets of precursor metal oxide nanoparticles. The gas‐phase conversion of these patterned ceramic nanoparticle sheets results in monolithic MOF objects with arbitrarily shaped geometries and thicknesses of up to hundreds of micrometers. The writing of complex patterns of zeolitic imidazolate framework‐8 (ZIF‐8) is demonstrated by a variety of approaches including ion beam, laser, and hand writing. Nanometer‐scale patterns are achieved by focused ion beam (FIB). Artless handwritings are obtained by using a pen in a similar fashion to writing on a paper. The pure ZIF‐8 composition of the resulting patterns is confirmed by a series of physical and chemical characterization. This facile MOF precursor‐writing approach provides novel opportunities for the design of MOF‐based devices with applications ranging from micro‐fluidics to renewable energy systems. [ABSTRACT FROM AUTHOR]

Water electrolysis powered by renewable electricity will likely be critical to a future hydrogen economy. However, the typical use of strongly acidic or alkaline electrolytes necessitates the use of expensive materials, while bubbles add to capital and operational costs, due to blocking of the electrode surface and the necessary use of pumps and gas-liquid separators. Here ' bubble-free ' oxygen evolution at mild pH is carried out using an electrocatalyst that mimics photosystem II (PSII). The bubble-free electrode includes a gas-extracting Gore-Tex® membrane. Edge-functionalised graphene (EFG) is included to mimic the metal-binding local protein environment, and the tyrosine residue, in the oxygen evolving complex (OEC) of PSII, while MnO x and Ca2+ are incorporated to mimic the Mn 4 CaO 5 cluster. Interaction between EFG, MnO x , and Ca2+ results in a significant, 130 mV fall in the overpotential required to drive electrocatalytic oxygen evolution at 10 mA cm−2, compared to the electrode without these biomimetic components. [Display omitted] • An electrocatalyst that mimics photosystem II is developed. • The biomimetic electrocatalyst is incorporated into a ' bubble-free ' electrode. • Enhanced oxygen evolution occurs due to the interaction of graphene, MnO x , and Ca2+. [ABSTRACT FROM AUTHOR]

Nanomedicine has seen a significant rise in the development of new research tools and clinically functional devices. In this regard, significant advances and new commercial applications are expected in the pharmaceutical and orthopedic industries. For advanced orthopedic implant technologies, appropriate nanoscale surface modifications are highly effective strategies and are widely studied in the literature for improving implant performance. It is well-established that implants with nanotubular surfaces show a drastic improvement in new bone creation and gene expression compared to implants without nanotopography. Nevertheless, the scientific and clinical understanding of mixed oxide nanotubes (MONs) and their potential applications, especially in biomedical applications are still in the early stages of development. This review aims to establish a credible platform for the current and future roles of MONs in nanomedicine, particularly in advanced orthopedic implants. We first introduce the concept of MONs and then discuss the preparation strategies. This is followed by a review of the recent advancement of MONs in biomedical applications, including mineralization abilities, biocompatibility, antibacterial activity, cell culture, and animal testing, as well as clinical possibilities. To conclude, we propose that the combination of nanotubular surface modification with incorporating sensor allows clinicians to precisely record patient data as a critical contributor to evidence-based medicine. Image 1 [ABSTRACT FROM AUTHOR]

The structuring of the metal‐organic framework material ZIF‐8 as films and membranes through the vapor‐phase conversion of ZnO fractal nanoparticle networks is reported. The extrinsic porosity of the resulting materials can be tuned from 4% to 66%, and the film thickness can be controlled from 80 nm to 0.23 mm, for areas >100 cm2. Freestanding and pure metal‐organic frameworks (MOF) membranes prepared this way are showcased as separators that minimize capacity fading in model Li‐S batteries. [ABSTRACT FROM AUTHOR]

The most pressing challenges for light‐driven hydrogel actuators include reliance on UV light, slow response, poor mechanical properties, and limited functionalities. Now, a supramolecular design strategy is used to address these issues. Key is the use of a benzylimine‐functionalized anthracene group, which red‐shifts the absorption into the visible region and also stabilizes the supramolecular network through π–π interactions. Acid–ether hydrogen bonds are incorporated for energy dissipation under mechanical deformation and maintaining hydrophilicity of the network. This double‐crosslinked supramolecular hydrogel developed via a simple synthesis exhibits a unique combination of high strength, rapid self‐healing, and fast visible‐light‐driven shape morphing both in the wet and dry state. As all of the interactions are dynamic, the design enables the structures to be recycled and reprogrammed into different 3D objects. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • 2:1 iron–manganese oxide for solar thermochemical energy storage. • DSC analysis under argon and air atmospheres. • Thermodynamic and kinetic studies of the thermal reduction of the material. • Shrinking core model coupled with non-linear regression for kinetic modelling. Abstract Spherical 0.5–1 mm iron–manganese oxide with the Fe/Mn molar ratio of 2:1 (Fe67) was studied for thermochemical energy storage (TCES) system. Iron and manganese oxide are abundant, low-cost, and non-toxic; three ideal materials characteristics for TCES applications. Fe67 was reduced in both argon and air environments. A thermogravimetric analyser (TGA) and differential scanning calorimeter (DSC) were used to investigate reaction kinetics and the enthalpy of reduction. A shrinking core model fit the non-isothermal kinetic data obtained from four heating rates. It is hypothesized that thermal reduction of Fe67 is controlled by oxygen internal diffusion for an inert atmosphere, while oxygen internal diffusion followed by oxygen external diffusion control the process in an air environment. A reduction reaction rate expression was derived and is useful for reactor design. This is the first kinetics investigation for Fe67 active redox material and its first consideration for TCES applications. [ABSTRACT FROM AUTHOR]

Manganese-based materials have unique redox properties, attractive to many applications in the energy, environment and biomedical sectors. In particular, Mn 3 O 4 is known to act as both an oxidising and a reducing agent. However, pH-dependence of the redox properties of Mn 3 O 4 nanoparticles is not yet well understood. In this study, Mn 3 O 4 nanoparticles were mechanochemically synthesised and their redox catalytic activities were studied under different pH conditions. Mn 3 O 4 nanoparticles with sizes between 10 and 90 nm were prepared via a mechanically-induced solid-state displacement reaction between MnCl 2 and K 2 CO 3 and subsequent heat treatment. The effect of pH on the oxidative decomposition of a model organic dye revealed that Mn 3 O 4 nanoparticles showed oxidative catalytic activity only when pH was below 5. At a higher pH, Mn 3 O 4 nanoparticles showed strong free-radical scavenging activities, suitable for reducing oxidative stress in many locations of the body and for creating new design of energy-storage materials. • Mn 3 O 4 nanoparticles were synthesised by a green method. • Effect of pH on the catalytic redox properties of Mn 3 O 4 was reported. • Mechanism of the pH dependent redox catalytic property was proposed. [ABSTRACT FROM AUTHOR]

In addition to a good perovskite light absorbing layer, the hole and electron transport layers play a crucial role in achieving high-efficiency perovskite solar cells. Here, a simple, one-step, solution-based method is introduced for fabricating high quality indium-doped titanium oxide electron transport layers. It is shown that indium-doping improves both the conductivity of the transport layer and the band alignment at the ETL/perovskite interface compared to pure TiO2, boosting the fill-factor and voltage of perovskite cells. Using the optimized transport layers, a high steady-state efficiency of 17.9% for CH3NH3PbI3-based cells and 19.3% for Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3-based cells is demonstrated, corresponding to absolute efficiency gains of 4.4% and 1.2% respectively compared to TiO2-based control cells. In addition, a steady-state efficiency of 16.6% for a semi-transparent cell is reported and it is used to achieve a four-terminal perovskite-silicon tandem cell with a steady-state efficiency of 24.5%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chitin nanofibers reduced the blood-clotting time and increased clot firmness. • The morphology of chitin nanofibers impacts their hemostatic properties. • The positively-charged surface of chitin stimulates contact activation pathways. Recently, negatively-charged nanofibers made of macro-scale carbohydrate polymers, such as cellulose, have been investigated for hemostatic applications. It was demonstrated that nanostructural features including specific surface area and aspect ratio can be optimized to increase the interaction of blood components with nanofibers. However, the influence of nanofiber's surface charge is unknown. In this paper, positively-charged nanofibers were produced from shrimp chitin using a ball-milling technique. In-vitro thromboelastometry studies revealed that nanofibers morphology has much stronger influence than the surface charge on their hemostatic efficacy. Consequently, with optimizing the morphology, clotting time was reduced by 70 ± 2%, and clot firmness was increased by 12 ± 1% comparable to commercial hemostats. [ABSTRACT FROM AUTHOR]

Widely known for its recreational use, the cannabis plant also has the potential to act as an antibacterial agent in the medicinal field. The analysis of cannabis plants/products in both pharmacological and forensic studies often requires the separation of compounds of interest and/or accurate identification of the whole cannabinoid profile. In order to provide a complete separation and detection of cannabinoids, a new two-dimensional liquid chromatography method has been developed using acidic potassium permanganate chemiluminescence detection, which has been shown to be selective for cannabinoids. This was carried out using a Luna 100 Å CN column and a Poroshell 120 EC-C18 column in the first and second dimensions, respectively. The method has utilized a large amount of the available separation space with a spreading angle of 48.4° and a correlation of 0.66 allowing the determination of more than 120 constituents and mass spectral identification of ten cannabinoids in a single analytical run. The method has the potential to improve research involved in the characterization of sensitive, complex matrices. [ABSTRACT FROM AUTHOR]

Abstract: This study examined the structure, thermal property, and ion adsorption of silk particles. The particles were prepared by attritor–bead mill combination, using alkaline (pH10) charge repulsion and surfactant steric repulsion methods. Both methods produced particles with a dominant β-sheet structure, similar to the silk fibre. There was no significant difference in the decomposition temperatures for either the silk fibre or the micro/nano silk particles. An important finding from this study is clear evidence of reduction of amorphous content during the final stage of powdering using the bead mill. As a result, despite reduction in β-sheet crystallites with the progressive milling, the relative β-sheet content actually increased during this process. However, intermolecular forces between the β-sheets reduced significantly and hence the XRD results showed significant reduction in crystallinity in nano silk particles but crystal forming segments remained with β-sheet conformations after milling. The structural change influenced the ion-adsorption property where particle-size reduction resulted in a significant increase in both the rate and volume of HCrO4 − adsorption. [Copyright &y& Elsevier]

The structural and optical properties of cobalt-doped zinc oxide (Co-doped ZnO) nanoparticles have been investigated. The nanopowder with Co concentrations up to 5 at% was synthesized by a co-precipitation method. The physical structure and the chemical states of the Co-doped ZnO were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, UV–Visible reflectance and cathodoluminescence (CL) spectroscopy. The results show that cobalt ions predominantly occupy Zn 2+ sites in the wurtzite crystal lattice and possess a valence state of 2+. CL analysis revealed that the incorporation of Co 2+ creates a new emission band at 1.85 eV, but quenched the near-band-edge luminescence. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we have investigated the optical and photocatalytic properties of nanoparticulate (TiO2) x (ZnO)1−x powders that were synthesised by mechanochemical processing. The objective was to establish the suitability of these powders for use as optically transparent ultraviolet light screening agents. It was found that the photocatalytic activity of single phase ZnO can be substantially reduced through the incorporation of TiO2 at the cost of a comparatively minor decrease in optical transparency. The composition given by (TiO2)0.10(ZnO)0.90 was characterised by a photocatalytic activity that was approximately 20% of that exhibited by the ZnO powder synthesised using similar processing conditions. These results demonstrate that (TiO2) x (ZnO)1−x powders synthesised by mechanochemical processing are potentially useful as optically transparent ultraviolet light screening agents. [Copyright &y& Elsevier]

Abstract: The crystallographic and optical properties of Mn-doped ZnO nanoparticles prepared by a sol–gel process have been investigated by X-ray diffraction, UV-visible absorption spectroscopy and cathodoluminescence microanalysis. X-ray diffraction reveals that the nanoparticles have hexagonal wurtzite crystal structure, with the lattice constants along the a- and c-axes increasing with increasing Mn concentration from 0 to 2.4at%. For all Mn concentrations in this range, the nanoparticles are essentially free of native point defects so that they exhibit only band-edge luminescence. The optical bandgap and band-edge emission energies for Mn-doped ZnO were found to increase in proportion to the lattice constants. The direct correlation between the bandgap and crystal structure suggests that the band-edge optical properties of Mn-doped ZnO is predominantly influenced by the amount of Mn atoms substituting Zn on the lattice sites. [Copyright &y& Elsevier]