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The effects of isothermal annealing on the self-assembled nanostructures of spinel manganese oxide ZnMnGaO4 were investigated using transmission electron microscopy and x-ray diffraction. The checkerboard nanostructures and zigzag nanostructures (named "Sierra" nanostructures) coexisted owing to the chemical phase separation of Mn3+ and Ga3+ ions by isothermal annealing at 575 °C. It was observed that the checkerboard nanostructures were dominant in short-time annealing and that the volume fraction of the Sierra nanostructures became more prominent as the annealing period increase. The interdiffusion of Mn3+ and Ga3+ is indicated to play an important role in gaining the total energy of the system by the reduction in the local strain caused by the formation of nanostructures. These results provide further insights into the fabrication of distinct types of nanostructures in complex transition-metal compounds. [ABSTRACT FROM AUTHOR]

Circular dichroism (CD) spectra for pseudo-two-dimensional chiral nanomaterials were systematically investigated and analyzed in relation to the rotational symmetry of the nanomaterials. Theoretically, an ideal two-dimensional chiral matter is CD inactive for light incident normal to the plane if it possesses threefold or higher rotational symmetry. If the matter has two- or onefold rotational symmetry, it should exhibit CD activity, and the CD signal measured from the back side of the matter is expected to be inverted from that measured from the front side. For pseudo-two-dimensional chiral gold nanostructures fabricated on glass substrates using electron beam lithography, matter with fourfold rotational symmetry is found to be CD active, even when special care is taken to ensure that the optical environments for the front and back sides of the sample are equivalent. In this case, the CD signal measured from the back side is found to be almost exactly the same as that measured from the front side. It is revealed that the observed chiro-optical behavior arises from three-dimensional chiral characteristics due to differences in the surface shape between the front and back sides of the structures. For matter that is two- or onefold rotationally symmetric, the CD signal measured from the back side is not coincident with that from the front side. For certain wavelength regions, the CD signals measured from the front side and back side are observed to be similar, while at other wavelengths, the inverted component of the CD signals is found to dominate. The observed CD spectral behavior for reciprocal optical measurement configurations is considered to be determined by a balance between the in-plane isotropic and anisotropic components of the chiral permittivity. [ABSTRACT FROM AUTHOR]

There have been major advances in the science to predict the likely environmental concentrations of nanomaterials, which is a key component of exposure and subsequent risk assessment. Considerable progress has been since the first Material Flow Analyses (MFAs) in 2008, which were based on very limited information, to more refined current tools that take into account engineered nanoparticle (ENP) size distribution, form, dynamic release, and better-informed release factors. These MFAs provide input for all environmental fate models (EFMs), that generate estimates of particle flows and concentrations in various environmental compartments. While MFA models provide valuable information on the magnitude of ENP release, they do not account for fate processes, such as homo- and heteroaggregation, transformations, dissolution, or corona formation. EFMs account for these processes in differing degrees. EFMs can be divided into multimedia compartment models (e.g., atmosphere, waterbodies and their sediments, soils in various landuses), of which there are currently a handful with varying degrees of complexity and process representation, and spatially-resolved watershed models which focus on the water and sediment compartments. Multimedia models have particular applications for considering predicted environmental concentrations (PECs) in particular regions, or for developing generic "fate factors" (i.e., overall persistence in a given compartment) for life-cycle assessment. Watershed models can track transport and eventual fate of emissions into a flowing river, from multiple sources along the waterway course, providing spatially and temporally resolved PECs. Both types of EFMs can be run with either continuous sources of emissions and environmental conditions, or with dynamic emissions (e.g., temporally varying for example as a new nanomaterial is introduced to the market, or with seasonal applications), to better understand the situations that may lead to peak PECs that are more likely to result in exceedance of a toxicological threshold. In addition, bioaccumulation models have been developed to predict the internal concentrations that may accumulate in exposed organisms, based on the PECs from EFMs. The main challenge for MFA and EFMs is a full validation against observed data. To date there have been no field studies that can provide the kind of dataset(s) needed for a true validation of the PECs. While EFMs have been evaluated against a few observations in a small number of locations, with results that indicate they are in the right order of magnitude, there is a great need for field data. Another major challenge is the input data for the MFAs, which depend on market data to estimate the production of ENPs. The current information has major gaps and large uncertainties. There is also a lack of robust analytical techniques for quantifying ENP properties in complex matrices; machine learning may be able to fill this gap. Nevertheless, there has been major progress in the tools for generating PECs. With the emergence of nano- and microplastics as a leading environmental concern, some EFMs have been adapted to these materials. However, caution is needed, since most nano- and microplastics are not engineered, therefore their characteristics are difficult to generalize, and there are new fate and transport processes to consider.

Cellulose nanocrystals (CNC) and nanofibers (CNF) have been broadly studied as renewable nanomaterials for various applications, including additives in cement and plastics composites. Herein, life cycle inventories for 18 previously examined processes are harmonized, and the impacts of CNC and CNF production are compared with a particular focus on GHG emissions. Findings show wide variations in GHG emissions between process designs, from 1.8-1100 kg CO2-eq/kg nanocellulose. Mechanical and enzymatic processes are identified as the lowest GHG emission methods to produce CNCs and CNFs. For most processes, energy consumption and chemical use are the primary sources of emissions. However, on a mass basis, for all examined production methods and impact categories (except CO emissions), CNC and CNF production emissions are higher than Portland cement and, in most cases, are higher than polylactic acid. This work highlights the need to carefully consider process design to prevent potential high emissions from CNCs and CNF production despite their renewable feedstock, and results show the magnitude of conventional material that must be offset through improved performance for these materials to be environmentally favorable.

The semiconducting behavior of two-dimensional (2D) metal nanostructures has recently attracted much interest for their possible applications in optoelectronics and others. In particular, tuning the bandgap of such nanostructures can open up a new avenue for fabricating functional nano-devices. In the present article, we report the synthesis of 2D metallic Zn nanosheets at room temperature using a ball mill, which is capable of producing large-scale materials in a single run. Initially, nanoplates were formed for ball milling the octahedral-shaped Zn nanoparticles for the time of milling of 6 h. Subsequent ball milling for another 6 h leads these nanoplates to nearly uniform nanosheets. The thickness of these 2D nanostructures was found to decrease with an increase in the time of milling. Visible photoluminescence (PL) emissions centered at ∼3, ∼2.9, and ∼2.75 eV were observed from all the Zn particles showing semiconductor behavior. The origin of such semiconductor behavior was explained based on the radiative transition of electrons from the sp band to the upper states of the 3d band. This argument was confirmed through the studies of photoelectron spectroscopy and the first principle calculations employing density functional theory (DFT). Furthermore, excitation-dependent PL studies indicated that the bandgap of the 2D Zn nanostructures decreased with the increase in the ball milling time. Therefore, a redshift in the bandgap was observed with the increase in the ball milling time. Such changes in the bandgap with the thickness of 2D Zn nanostructures were also verified from the studies of DFT. Thus, the present study demonstrated that the bandgap of 2D metallic Zn nanostructures could be effectively tuned by reducing the thickness. [ABSTRACT FROM AUTHOR]

The present investigation involves the in situ growth of Ag nanostructures (NSs) onto a rough Cu surface, accomplished through a cost-effective and straightforward fabrication process. The inherent characteristics of the Cu surface contribute to a certain degree of a surface-enhanced Raman spectroscopy (SERS) signal. Upon integration with Ag NSs, the Cu surface serves as an exceptionally sensitive and consistently uniform substrate for surface-enhanced Raman spectroscopy. Notably, a singular substrate accommodates the simultaneous detection of four distinct probe molecules. Subsequent SERS analyses of Ag NSs on Cu were executed under varying laser power conditions. Intriguingly, despite the escalation in laser power, no substantial shifts were discerned in the peak positions corresponding to the probe molecules. Consequently, it can be inferred that, for investigations where peak position shifts hold significance, the utilization of a thermally conductive material in fabricating SERS-active substrates could confer notable advantages. [ABSTRACT FROM AUTHOR]

From the perspective of a bond-order-length-strength correlation, we put forward an analytical solution to describe the size, shape, and wall thickness dependency of melting temperature, entropy, and enthalpy for metallic nanostructures. Theoretical reproduction of measurements clarified that (i) when the crystal size reduces, the atomic coordination number lowers, the atomic cohesive energy decreases, and the surface-to-volume ratio increases; (ii) at the same equivalent radius, with the decrease in the number of sides for polyhedral nanoparticles and polygonal nanowires or nanotubes, the melting temperature, entropy, and enthalpy depress; and (iii) the melting temperature, entropy, and enthalpy of nanotubes are always lower than those of nanowires with the same cross-sectional radius. The present formulation is accurate and convenient, which not only shows deeper insight into the physical origins of a melting thermodynamic property response to perturbations but also provides guidance for the design and optimization of electronic nanodevices. [ABSTRACT FROM AUTHOR]

The effects of isothermal annealing on the self-assembled nanostructures of spinel manganese oxide ZnMnGaO4 were investigated using transmission electron microscopy and x-ray diffraction. The checkerboard nanostructures and zigzag nanostructures (named "Sierra" nanostructures) coexisted owing to the chemical phase separation of Mn3+ and Ga3+ ions by isothermal annealing at 575 °C. It was observed that the checkerboard nanostructures were dominant in short-time annealing and that the volume fraction of the Sierra nanostructures became more prominent as the annealing period increase. The interdiffusion of Mn3+ and Ga3+ is indicated to play an important role in gaining the total energy of the system by the reduction in the local strain caused by the formation of nanostructures. These results provide further insights into the fabrication of distinct types of nanostructures in complex transition-metal compounds. [ABSTRACT FROM AUTHOR]

Photocathodic conversion of NAD+ to NADH cofactor is a promising platform for activating redox biological catalysts and enzymatic synthesis using renewable solar energy. However, many photocathodes suffer from low photovoltage, consequently requiring a high cathodic bias for NADH production. Here, we report an n+p-type silicon nanowire (n+p-SiNW) photocathode having a photovoltage of 435 mV to drive energy-efficient NADH production. The enhanced band bending at the n+/p interface accounts for the high photovoltage, which conduces to a benchmark onset potential [0.393 V vs the reversible hydrogen electrode (VRHE)] for SiNW-based photocathodic NADH generation. In addition, the n+p-SiNW nanomaterial exhibits a Faradaic efficiency of 84.7% and a conversion rate of 1.63 μmol h-1 cm-1 at 0.2 VRHE, which is the lowest cathodic potential to achieve the maximum productivity among SiNW-sensitized cofactor production.

The tunability of chromatic phases adapted by chromogenic polymers such as polydiacetylene (PDA) is key to their utility for robust sensing applications. Here, we investigated the influence of charged peptide interactions on the structure-dependent thermochromicity of amphiphilic PDAs. Solid-state NMR and circular dichroism analyses show that our oppositely charged peptide-PDA samples have distinct degrees of structural order, with the coassembled sample being in between the β-sheet-like positive peptide-PDA and the relatively disordered negative peptide-PDA. All solutions exhibit thermochromicity between 20 and 80 °C, whereby the hysteresis of the blue, planar phase is much larger than that of the red, twisted phase. Resonance Raman spectroscopy of films demonstrates that only coassemblies with electrostatic complementarity stabilize coexisting blue and red PDA phases. This work reveals the nature of the structural changes responsible for the thermally responsive chromatic transitions of biomolecule-functionalized polymeric materials and how this process can be directed by sequence-dictated electrostatic interactions.

The temperature coefficient of resistivity (θ T) of carbon-based materials is a critical property that directly determines their electrical response upon thermal impulses. It could have metal- (positive) or semiconductor-like (negative) behavior, depending on the combined temperature dependence of electron density and electron scattering. Its distribution in space is very difficult to measure and is rarely studied. Here, for the first time, we report that carbon-based micro/nanoscale structures have a strong non-uniform spatial distribution of θ T. This distribution is probed by measuring the transient electro-thermal response of the material under extremely localized step laser heating and scanning, which magnifies the local θ T effect in the measured transient voltage evolution. For carbon microfibers (CMFs), after electrical current annealing, θ T varies from negative to positive from the sample end to the center with a magnitude change of >130% over <1 mm. This θ T sign change is confirmed by directly testing smaller segments from different regions of an annealed CMF. For micro-thick carbon nanotube bundles, θ T is found to have a relative change of >125% within a length of ∼2 mm, uncovering strong metallic to semiconductive behavior change in space. Our θ T scanning technique can be readily extended to nm-thick samples with μm scanning resolution to explore the distribution of θ T and provide a deep insight into the local electron conduction. [ABSTRACT FROM AUTHOR]

Machine learning (ML) methods are of rapidly growing interest for materials modeling, and yet, the use of ML interatomic potentials for new systems is often more demanding than that of established density-functional theory (DFT) packages. Here, we describe computational methodology to combine the CASTEP first-principles simulation software with the on-the-fly fitting and evaluation of ML interatomic potential models. Our approach is based on regular checking against DFT reference data, which provides a direct measure of the accuracy of the evolving ML model. We discuss the general framework and the specific solutions implemented, and we present an example application to high-temperature molecular-dynamics simulations of carbon nanostructures. The code is freely available for academic research. [ABSTRACT FROM AUTHOR]

The three-dimensional (3D) nanosized compactness of devices is in high demand for the spintronic-device applicability. However, very few self-organized, periodic magnetic 3D nanostructures of transition metal oxides are known. Here, we report the direct microscopic evidence of a self-assembled, square-shaped, periodic array of coherent orthogonal nanoblock-type structure in an epitaxial SrRuO3 (SRO) thin film (∼90 nm thickness) grown on (001) LaAlO3 (LAO) using pulsed-laser deposition technique. The evolution of different growth facets of SRO over the LAO single crystalline substrate with different thickness are observed. The combined effect of substrate-induced strain and misfit is utilized to grow such self-assembled, ordered nanostructure. The spontaneous formation of such ordered ferromagnetic nano-devices can fill the gap of a miniaturized spintronic device for magnetic memory-based applications. [ABSTRACT FROM AUTHOR]

Nanostructured topological insulators (TIs) have the potential to impact a wide array of condensed matter physics topics, ranging from Majorana physics to spintronics. However, the most common TI materials, the B i 2 S e 3 family, are easily damaged during nanofabrication of devices. In this paper, we show that electron beam lithography performed with a 30 or 50 kV accelerating voltage—common for nanopatterning in academic facilities—damages both nonmagnetic TIs and their magnetically doped counterparts at unacceptable levels. We additionally demonstrate that electron beam lithography with a 10 kV accelerating voltage produces minimal damage detectable through low-temperature electronic transport. Although reduced accelerating voltages present challenges in creating fine features, we show that with careful choice of processing parameters, particularly the resist, 100 nm features are reliably achievable. [ABSTRACT FROM AUTHOR]

Low dimensional ZnO-based materials have drawn much attention for the past few decades due to their unique electronic and optical properties and potential applications in optoelectronic devices. In this Tutorial, we will cover the past and the latest developments in ZnO thin films and micro/nanostructures in terms of excitonic and related lasing processes. First, we give a brief overview of structural and band properties of ZnO along with the linear optical and excitonic properties. Second, we introduce a feedback mechanism for lasing in various forms of ZnO, ranging from nanoparticles to nanowires, nanodisks, and thin films. As for the feedback mechanism, detailed descriptions are given to random lasing, Fabry–Pérot lasing, and whispering gallery mode lasing. Third, we discuss possible gain mechanisms, i.e., excitonic gain and electron–hole plasma (EHP) gain, in ZnO. A special interest is also devoted to the Mott carrier density, which is a crucial parameter to distinguish between excitonic and EHP contributions to lasing. Lastly, recent developments on exciton–polariton lasers based on ZnO microcavities are introduced. [ABSTRACT FROM AUTHOR]

Sequence-encoded biomolecules such as DNA and peptides are powerful programmable building blocks for nanomaterials. This paradigm is enabled by decades of prior research into how nucleic acid and amino acid sequences dictate biomolecular interactions. The properties of biomolecular materials can be significantly expanded with non-natural interactions, including metal ion coordination of nucleic acids and amino acids. However, these approaches present design challenges because it is often not well-understood how biomolecular sequence dictates such non-natural interactions. This Feature Article presents a case study in overcoming challenges in biomolecular materials with emerging approaches in data mining and machine learning for chemical design. We review progress in this area for a specific class of DNA-templated metal nanomaterials with complex sequence-to-property relationships: DNA-stabilized silver nanoclusters (AgN-DNAs) with bright, sequence-tuned fluorescence colors and promise for biophotonics applications. A brief overview of machine learning concepts is presented, and high-throughput experimental synthesis and characterization of AgN-DNAs are discussed. Then, recent progress in machine learning-guided design of DNA sequences that select for specific AgN-DNA fluorescence properties is reviewed. We conclude with emerging opportunities in machine learning-guided design and discovery of AgN-DNAs and other sequence-encoded biomolecular nanomaterials.

Mass spectrometry (MS) enables detection of different chemical species with a very high specificity; however, it can be limited by its throughput. Integrating MS with microfluidics has a tremendous potential to improve throughput and accelerate biochemical research. In this work, we introduce Drop-NIMS, a combination of a passive droplet loading microfluidic device and a matrix-free MS laser desorption ionization technique called nanostructure-initiator mass spectrometry (NIMS). This platform combines different droplets at random to generate a combinatorial library of enzymatic reactions that are deposited directly on the NIMS surface without requiring additional sample handling. The enzyme reaction products are then detected with MS. Drop-NIMS was used to rapidly screen enzymatic reactions containing low (on the order of nL) volumes of glycoside reactants and glycoside hydrolase enzymes per reaction. MS "barcodes" (small compounds with unique masses) were added to the droplets to identify different combinations of substrates and enzymes created by the device. We assigned xylanase activities to several putative glycoside hydrolases, making them relevant to food and biofuel industrial applications. Overall, Drop-NIMS is simple to fabricate, assemble, and operate and it has potential to be used with many other small molecule metabolites.

Clustered randomly interspaced short palindromic repeats (CRISPRs) and its associated endonuclease protein, i.e., Cas9, have been discovered as an immune system in bacteria and archaea; nevertheless, they are now being adopted as mainstream biotechnological/molecular scissors that can modulate ample genetic and nongenetic diseases via insertion/deletion, epigenome editing, messenger RNA editing, CRISPR interference, etc. Many Food and Drug Administration-approved and ongoing clinical trials on CRISPR adopt ex vivo strategies, wherein the gene editing is performed ex vivo, followed by reimplantation to the patients. However, the in vivo delivery of the CRISPR components is still under preclinical surveillance. This review has summarized the nonviral nanodelivery strategies for gene editing using CRISPR/Cas9 and its recent advancements, strategic points of view, challenges, and future aspects for tissue-specific in vivo delivery of CRISPR/Cas9 components using nanomaterials.

RNA origami is a method for designing RNA nanostructures that can self-assemble through co-transcriptional folding with applications in nanomedicine and synthetic biology. However, to advance the method further, an improved understanding of RNA structural properties and folding principles is required. Here we use cryogenic electron microscopy to study RNA origami sheets and bundles at sub-nanometre resolution revealing structural parameters of kissing-loop and crossover motifs, which are used to improve designs. In RNA bundle designs, we discover a kinetic folding trap that forms during folding and is only released after 10 h. Exploration of the conformational landscape of several RNA designs reveal the flexibility of helices and structural motifs. Finally, sheets and bundles are combined to construct a multidomain satellite shape, which is characterized by individual-particle cryo-electron tomography to reveal the domain flexibility. Together, the study provides a structural basis for future improvements to the design cycle of genetically encoded RNA nanodevices.

Artificial vision systems pervade our daily lives as a foremost sensing apparatus in various digital technologies, from smartphones to autonomous cars and robotics. The broad range of applications for conventional vision systems requires facile adaptation under extreme and dynamic visual environments. However, these current needs have complicated individual visual components for high-quality image acquisition and processing, which indeed leads to a decline in efficiency in the overall system. Here, we review recent advancements in visual components for high-performance visual processing based on strategies of biological eyes that execute diverse imaging functionalities and sophisticated visual processes with simple and concise ocular structures. This review first covers the structures and functions of biological eyes (i.e., single-lens eyes and compound eyes), which contain micro-optic components and nanophotonic structures. After that, we focus on their inspirations in imaging optics/photonics, light-trapping and filtering components, and retinomorphic devices. We discuss the remaining challenges and notable biological structures waiting to be implemented.

For obtaining new metal matrix composites, one needs to develop approaches to the selection of reinforcing additives, the identification of the relationship of the properties of the resulting material with the composition, concentration and morphology of the additives introduced, the creation and search for new affordable and cheap additives. As one of the solutions to this problem, the authors propose to obtain aluminum matrix composites based on the structuring of an Al matrix with titanium carbide nanostructures ($\leq 5$ nm) by atomic layer deposition (ALD). The resulting material has an important feature — the absence of obvious interface boundaries between the Al matrix and the reinforcing carbide phase, that ensures the components binding into a single whole. Composites, for the hardening of which a reinforcing phase with surface carbide nanostructures is used, in addition to a higher tensile strength, demonstrate a more plastic fracture pattern characteristic of dispersed hardening of materials. With an increase in the amount of the composite reinforcement from 1 to $5\%$, embrittlement of the material does not occur, as is observed when carbide particles are introduced into the Al matrix by other methods.

Semiconductor nanocrystals with an anisotropic morphology exhibit unique properties, most notably their linear polarization. The colloidal growth of semiconductor nanorods with core dots inside, also referred to as dot-in-rod (DIR) structure, has enabled the synthesis of anisotropic nanocrystals with better stability and controllable fluorescence polarization. In this study, we synthesize CdSe/CdS DIR nanocrystals, in which the position of the CdSe core particle can be controlled by using different ligand compositions during the CdS growth. Varying the core position within the DIR structure, e.g., from the center to the end of the DIR particles, results in a change in the degree of linear polarization. When the core is positioned at the center of the nanorod, the linear polarization turns out to be higher compared with tip-core DIRs. Time-resolved photoluminescence analysis reveals that the center-core DIRs have higher electron–hole interaction than tip-core DIRs because of weak uniaxial strain in center-core DIR that arises from lattice dislocations at the interface to relieve accumulated strain. [ABSTRACT FROM AUTHOR]

Polymer templates are critical in the preparation of ceramic fibers from precursor solutions, but the available options are limited. Here, ZrO 2 nanofiber films and aerogels are developed by solution blow spinning method using hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) as templates. The effects of HPMC ratio, polymer concentration, and calcination temperature on the morphology and structure of the ZrO 2 nanofibers are investigated. The nanofiber films with an areal density of 20 mg cm−2 exhibit excellent filtration property, achieving a filtration efficiency of 94.94% and a pressure drop of 136 Pa at an airflow velocity of 32 L min−1. The nanofiber aerogels display low density of 50 mg cm−3, low thermal conductivity of 0.039 W m−1 K−1, as well as superior compressibility, demonstrating significant potential for thermal protection applications. This work expands the formation template option of ceramic fibers, offering significant guidance in the development of flexible, high-temperature-resistant ceramic fiber materials. [ABSTRACT FROM AUTHOR]

For the first time, the S-doped g-C 3 N 4 nanostructures (SCN(x)) were prepared by the reflux method as an aqueous-based method with different weight ratios of Na 2 S (x) and then characterized. The results of S-doped g-C 3 N 4 nanostructures confirmed the presence of sulfur doping in the g-C 3 N 4 structure. Moreover, these nanostructures showed superior photocatalytic efficiency compared to the bulk g-C 3 N 4. Among different SCN(x) nanostructures, SCN(0.2) showed the most remarkable photocatalytic performance. This outcome is attributed to a decrease in the band gap of this sample. The FESEM analysis indicated that the nanoparticles tended to adhere together in SCN(0.2) nanostructure. This phenomenon has led to the reduction of surface roughness, and improving the surface texture quality of this nanostructure. On the other hand, the lowest FWHM and PL peak intensity show an increase in crystallinity and a decrease in the amount of recombination in this nanostructure. Moreover, the evaluation of electrochemical impedance and optical current showed a decrease in the semi-circular pattern and an increase in photocurrent for the optimal sample of SCN (0.2) compared to the bulk g-C 3 N 4. Therefore, the results of investigating the photocatalytic performance of the synthesized nanostructures show that the SCN(x) nanostructures have higher efficiency compared to the bulk g-C 3 N 4. In addition, the SCN(0.2)) sample showed the highest photocatalytic efficiency. Compared to the other conventional deposition methods based on electrostatic or van der Waals forces, this study suggests that using the reflux technique to substitute sulfur in the g-C 3 N 4 can be a successful approach due to the chemical bonding on to host framework. Moreover, this method may provide a facile aqueous-based route for doping in the g-C 3 N 4 layered structure and can offer advantages compared to other common method such as simple, low cost, excellent distribution uniformity, fast reaction kinetics, high levels of purity, and environmentally friendly process. [ABSTRACT FROM AUTHOR]

Here in the present work, simple, eco-friendly and economical method of synthesis has been approached known as hydrothermal synthesis that allowed easy doping of Fe ions into the ZnS host lattice. A unique approach was adopted for the first time to prepare ZnS material where thioglycolic acid (TGA) was used as a source for sulfur in addition to a reducing and capping agent. Properties of the nanostructures were explored using different techniques. The X-ray diffraction (XRD) results indicated formation of single phase hexagonal ZnS material where inclusion of Fe2+ ions into the ZnS lattice have no influence on the crystal phase of the material. Probably almost identical sizes of Zn2+ and Fe2+ ions made this possible that indicated Fe2+ ions take Zn2+ vacant sites by substitution of Zn2+ ions by Fe2+ ions. Chemical analysis (X-ray photoelectron spectroscopy) performed discovered that Zn and Fe ions were present in +2 oxidation states whereas S is in −2 state. Anisotropic growth of the nanostructures is reported where irregular shaped nanostructures of varying dimensions were formed that agglomerated as doping concentration was increased to form spherical microstructures. Inclusion of Fe ions into the host material modified magnetic behavior of the nanostructures converting diamagnetic ZnS into a ferromagnetic material. Optical properties were also influence by the doping resulting in photon absorption at different wavelengths. The band gap got reduced from 3.2 eV to 2.7 eV making the ZnS nanostructures visible light active. The nanostructures with band gap 2.7 eV exhibited good photocatalytic activity against methylene blue (MB) dye under visible light illumination degrading 94% of the dye in just 2 h. The scavenging experiments performed showed hydroxyl free radicals play an active role in mineralizing the dye. Reusability and post photocatalytic properties of the photocatalysts determined their stability and potential ability for possible commercialization. [ABSTRACT FROM AUTHOR]

The study of physical properties of compound semiconductors plays a vital role in the device fabrication point of view. Different investigations suggest that one can tune these properties by impurity dopants, irradiation techniques, adopting different synthesis techniques, etc. In this study, the physical properties of nanostructured thin films of Se–S compound were tuned by different Hg dopant concentrations. X-ray diffraction spectra clarify the preferred crystallite growth occurs in the cubic phase of the corresponding Bravi’s crystal system. The particle size calculated from Bragg’s reflection spectra by using Scherrer’s analytical formula illustrates an enhancement of crystallite size in highly concentrated Hg-doped sample. Similar consequences are found in surface morphological micrographs. The optical band gap reduced from 1.65eV to 1.54eV on increasing the doping concentration of Hg, according to the computed optical parameters using optical transmission spectra in the wavelength range 200–1100nm. The thin-film refractive index dispersion data fits well in accordance with the single oscillator model. Investigation of electrical properties tells that there is significant improvement in electrical conductivity in highly concentrated Hg-doped samples. Therefore, the apparent tuning as observed in the physical properties of the investigated material may have practical uses in industry for a variety of optoelectronic devices. [ABSTRACT FROM AUTHOR]

To study the influence of nitrogen on the properties of Sb2O3 nanostructures, a synthetic strategy was adopted to insert nitrogen into Sb2O3 lattice. Sb2O3 nanostructures were synthesized by vapor transport technique utilizing Ar plus O2 and N2 plus O2 gas mixes. EDAX inferred the presence of N besides to Sb and O for the films synthesized with N2 flow. This was also confirmed by presence of two small absorption bands around 2967.22 and 1052.00 cm− 1 in the FTIR spectrum. The insertion of N reduces the peak intensities of the cubic Sb2O3 phase and changed the morphology from randomly oriented nanowires to nanospheres/nanoprisms. The evaluated optical band gap values were 3.31 and 2.67 eV for the films synthesized with Ar and N2 flows, respectively. In addition to the two emission peaks around 397 and 467 nm which were observed for the films synthesized with Ar flows, the films synthesized with N2 flows had additionally enhanced red emission band with a maximum at 682 nm. Nitrogen increased the specific magnetization and maintained the diamagnetic behavior. The N doped Sb2O3 nanospheres/nanoprisms may be used as effective red-light emitters. [ABSTRACT FROM AUTHOR]

Composites of rhenium (ReNP) and rhenium–copper nanoparticles (ReCuNP) were studied as catalysts for the decomposition of the oxidizer ammonium perchlorate (AP) for composite solid propellants. Both composites were prepared by reducing ammonium perrhenate (NH4ReO4) and copper chloride (CuCl2) in the presence of polyamidoamine (PAMAM) dendrimers. The PAMAM-based nanostructures were characterized by transmission electron microscopy (TEM), high resolution TEM, and X-ray photoelectron spectroscopy. ReNP@PAMAM samples showed rhenium clusters and partially oxidized spherical nanoparticles of approx. 1 nm in diameter, while ReCuNP@PAMAM comprised nanoparticles of 6 nm in average size with different shapes and high-size dispersion. The computational description demonstrated the higher stability of the interaction between copper and PAMAM than perrhenate anion due to the charge transfer from the dendrimer to the cation. The materials were evaluated for the catalytic decomposition of AP by calorimetry. The catalytic performance of ReCuNP@PAMAM was superior to that of ReNP@PAMAM, lowering the decomposition of AP at high temperatures. However, the latter composite increased the energy release drastically due to the exothermic oxidation of rhenium metal. [ABSTRACT FROM AUTHOR]

Tritium retention in plasma-facing materials is a critical issue that can significantly impact the long-term and steady-state operation of fusion devices. The experiments conducted in the laboratory device MIES have confirmed that the presence of the tungsten (W) nanostructure (called 'fuzz') leads to a substantial retention of hydrogen isotopes within W fuzz layer. This observation motivates us to conduct dedicated modeling to investigate the influence of W nanostructures on deuterium (D) retention using the three-dimensional kinetic Monte Carlo code SURO-FUZZ. The SURO-FUZZ code offers a great flexibility in generating diverse microscopic structures of the W fuzzy surface through the quartet structure generation set (QSGS) approach, which allows us to explore the effects of the pore size and shape on D retention. In this study, several different W nanostructures generated by QSGS approach are utilized to conduct a comprehensive comparison between MIES experiments and SURO-FUZZ simulations. It is demonstrated that the simulated D retention can be brought into a reasonable agreement with the experimental data. On this basis, predictive estimations of D retention on EAST and ITER have been performed with SURO-FUZZ modeling. The simulation results indicate that the total D retention induced by W fuzz remains well below the administrative limit of 700 g. [ABSTRACT FROM AUTHOR]

A unified qualitative model is presented to study the impact of size, shape, crystal structure and dimension on the energy band gap of nanostructures. The formulated approach is based on the Bond energy model used to determine the relative melting temperature of nanosolids. The model approach depends on size, dimension, crystal structure and shapeof nanomaterial. The study is done on AlN, AlP, AlAs, GaN, GaP, GaAs. The formulation is obtained using the Arrhenius relation of electrical conductivity and is used to determine energy band gap expansion with respect to diameter/height of the nanostructures of different shapes. Depending on the shape of the nanomaterial, the surface area to volume ratio varies in nanomaterials that results in the change in the energy band gap value in nanostructure of same size. The study reveals that parameters viz. size, size, shape, crystal structure and dimension results in change in energy band gap value that enhance the possibility of tuning the optical properties of nanostructures. The model results are compared with the simulated and experimental data available and good agreement of model results with compared data is observed. The shifts in band gap energy of valence and conduction band is determined from the study in GaAs nanosolid. Drop in size at nano level results in increase the band gap energy leading to Raman blue shift. [ABSTRACT FROM AUTHOR]

Among the major challenges facing the hydrogen economy is the issue of hydrogen storage. In terms of "future energy needs", electrochemical hydrogen storage in solid-state materials is an accepted perspective that could mitigate the discontinuation of primary energy sources. In this study, we demonstrate the electrochemical properties of a complex metal oxide that contains the molybdate group, Dy 2 Mo 3 O 12. Wet-chemical synthesis of nanostructured Dy 2 Mo 3 O 12 is primarily carried out using ultrasound-assisted wet-chemical methods in the presence of a variety of surfactants. The structural and morphological observations of the samples confirm a pure and highly crystalline structure obtained in the presence of CTAB surfactant at 900 °C and 30 min of sonication, with an average crystalline size of 29 nm. Based on the FTIR spectrum of this sample, it can be concluded that there are significant absorptions indicating the formation of oxygen-metal bonds. The specific surface area and pore volume of the selected sample are 4.543 m2/g and 0.0284 cm3/g, respectively, demonstrating its porous structure. Electrochemical studies of this sample at various temperatures have revealed an enhanced discharge capacity (5100 mAh/g at 65 °C) with a capacity retention rate of 97%. Based on these findings, mixed metal oxides containing at least one active charge transfer species (Red./Ox.) are suitable for use in solid-state hydrogen storage devices. [Display omitted] • Pioneering technique for creating Dy 2 Mo 3 O 12 -Dy 2 O 3 nanocomposites. • Showcasing a unique material that holds potential for enhanced electrochemical hydrogen storage. • Significant strides in achieving enhanced electrochemical hydrogen storage. • Foundational step in the exploration of materials designed for harvesting hydrogen storage systems. [ABSTRACT FROM AUTHOR]

This work demonstrates the significant prospective of GaO/ZnO hybrid nanostructures for high-performance hydrogen gas sensing. The wavy grains of GaO support the structural transformation of ZnO nanorod into nanosheets by providing appropriate nucleation sites for ZnO growth. Compared to pure ZnO and GaO, GaO/ZnO exhibited a sixfold increase in H 2 response (60% at 500 ppm), excellent selectivity towards H 2 among other interfering gases, and outstanding long-term stability (retaining 98% of its initial response after 36 days). This greater performance rises from the unique morphology and different surface interactions within the GaO/ZnO hybrid nanostructure, assisting multiple adsorption sites and various hydrogen interaction pathways. Alloying effects, internal strain, and the presence of both GaO and ZnO regions within the nanosheets further contribute to enhanced sensitivity, selectivity, and stability. [Display omitted] • A novel strategy is used to combine GaO and ZnO as a hybrid nanostructure for H 2 detection. • GaO/ZnO nanorods transform into 2D nanosheets. • This transformation yields a H 2 sensor with high response (60% at 500 ppm) and stability. • Exceptional performance of GaO/ZnO stems from alloying, strain, and H₂ spillover synergy. [ABSTRACT FROM AUTHOR]

With the aim of obtaining new composites from graphene oxide for a new biological application, it urged us to select some amine containing molecules namely purpald, mafenide acetate and fluvoxamine for grafting that was resulted to the formation of purpald‐grafted graphene oxide, mafenide‐grafted graphene oxide and fluvoxamine‐grafted graphene oxide, respectively. These novel nanocomposites were evaluated by X‐ray photoelectron spectroscopy, Transmission electron microscopy, Field emission scanning electron microscopy,Dynamic light scattering, Zeta potential, X‐ray diffraction, Thermogravimetric analysis, Raman, and Fourier‐transform infrared. The findings demonstrated that the grafting was done satisfactorily. X‐ray photoelectron spectroscopy analysis revealed that the peaks seen at 286.07, 285.79, and 285.49 eV corresponded to the formation of carbon‐nitrogen bonds between the amine groups of purpald, mafenide acetate, and fluvoxamine, respectively, and the functionalized oxygen groups present on the surface of graphene oxide. In this study, three nanocomposites were subjected to practical testing in close proximity to human breast cancer cells. After a period of 24 hours, it was shown that purpald‐grafted graphene oxide demonstrated more cellular toxicity compared to the other nanocomposites. [ABSTRACT FROM AUTHOR]

Gelatin, a renowned natural biomaterial, has a significant impact as a polymeric substance in the sol-gel synthesis of nanoparticles. This comprehensive review is divided into two primary sections, which shed light on the various applications of gelatin. The first part of the manuscript explores the utilization of gelatin as both a stabilizer and a reducing agent. By harnessing energy, novel metal ions like Ag and Au are effectively reduced in gelatin media. Gelatin plays a crucial role in this process by providing the necessary electrons for the reduction of M+ to M°. Moreover, gelatin's extensive molecular chains make it an excellent stabilizer as they entrap the particles. These distinctive properties qualify gelatin to be an ideal stabilizer in the laser ablation method. The second part of the review focuses on the combustion behavior of gelatin. During the combustion process, gelatin expands approximately 50-fold in a remarkably short period, effectively hindering the growth of nanoparticles. This exceptional characteristic has been harnessed to synthesize pure and doped ZnO nanoparticles. The results of these experiments were thoroughly examined and compared. Furthermore, the research delves into the capability of gelatin to synthesize various mixed oxide nanocomposites. In summary, gelatin proves to be an exceptional bio-polymer that can serve as an agent in the sol-gel method for the production of nanostructures, particularly nanoparticles. Its unique attributes as a stabilizer and reducing agent, along with its combustion behavior, make it an invaluable component in nanoparticle synthesis. [ABSTRACT FROM AUTHOR]

The induced ferromagnetic behaviour and defect analysis of the undoped, Ni doped SrSnO 3 nanostructures are examined. The undoped and Ni doped SrSnO 3 (SSO) nanostructures crystallized in the orthorhombic perovskite structure, and show local structural disorders on vibrational spectroscopic analysis. The electron micrographs are witnessed rod type morphology for pure SrSnO 3 and corals for Ni doped compounds. The oxidation states of elements and presence of oxygen vacancies are identified. The sharp optical absorption behaviour resulted in reduction of optical band gap. Positron annihilation spectroscopy (PAS) studies reveal the presence of site-specific intrinsic defects of considerable concentration and their consequential effect on doping. PAS significantly showed that Schottky-type V Sn and V Sr-XO complexes in undoped SSO. The addition of Ni2+ results in the reduction of V Sr – O and the formation of Ni2+-V O -Ni2+ defect complexes. The EPR spectra show the signal with g value of 2.2432. The appearance of RT ferromagnetism could be attributed to the defects, F -center exchange (FCE) interactions in Ni-doped SSO nanostructures. [ABSTRACT FROM AUTHOR]

Simple Summary: Pancreatic ductal adenocarcinoma (PDAC) accounts for 90% of pancreatic cancers. It is considered one of the deadliest cancers due to its high metastatic potential and drug resistance. This review discusses various targets and nanoparticle-based delivery systems developed, tested, and approved for the effective diagnosis and targeted treatment of PDAC. Pancreatic ductal adenocarcinoma (PDAC), one of the deadliest cancers, presents significant challenges in diagnosis and treatment due to its aggressive, metastatic nature and lack of early detection methods. A key obstacle in PDAC treatment is the highly complex tumor environment characterized by dense stroma surrounding the tumor, which hinders effective drug delivery. Nanotechnology can offer innovative solutions to these challenges, particularly in creating novel drug delivery systems for existing anticancer drugs for PDAC, such as gemcitabine and paclitaxel. By using customization methods such as incorporating conjugated targeting ligands, tumor-penetrating peptides, and therapeutic nucleic acids, these nanoparticle-based systems enhance drug solubility, extend circulation time, improve tumor targeting, and control drug release, thereby minimizing side effects and toxicity in healthy tissues. Moreover, nanoparticles have also shown potential in precise diagnostic methods for PDAC. This literature review will delve into targeted mechanisms, pathways, and approaches in treating pancreatic cancer. Additional emphasis is placed on the study of nanoparticle-based delivery systems, with a brief mention of those in clinical trials. Overall, the overview illustrates the significant advances in nanomedicine, underscoring its role in transcending the constraints of conventional PDAC therapies and diagnostics. [ABSTRACT FROM AUTHOR]

Simple Summary: Glioblastoma is the most common malignant brain cancer and is associated with poor prognosis, with an average survival after diagnosis of less than 18 months. Hundreds of clinical trials have been conducted, with more underway to make progress in treating glioblastoma. This review details conventional and emergent targeted therapies for glioblastoma. Glioblastoma is most commonly a primary brain tumor and the utmost malignant one, with a survival rate of approximately 12–18 months. Glioblastoma is highly heterogeneous, demonstrating that different types of cells from the same tumor can manifest distinct gene expression patterns and biological behaviors. Conventional therapies such as temozolomide, radiation, and surgery have limitations. As of now, there is no cure for glioblastoma. Alternative treatment methods to eradicate glioblastoma are discussed in this review, including targeted therapies to PI3K, NFKβ, JAK-STAT, CK2, WNT, NOTCH, Hedgehog, and TGFβ pathways. The highly novel application of oncolytic viruses and nanomaterials in combating glioblastoma are also discussed. Despite scores of clinical trials for glioblastoma, the prognosis remains poor. Progress in breaching the blood–brain barrier with nanomaterials and novel avenues for targeted and combination treatments hold promise for the future development of efficacious glioblastoma therapies. [ABSTRACT FROM AUTHOR]

In recent decades, peptide amphiphiles (PAs) have established themselves as promising self-assembling bioinspired materials in a wide range of medical fields. Herein, we report a dual-therapeutic system constituted by an antimicrobial PA and a cylindrical protease inhibitor (LJC) to achieve broad antimicrobial spectrum and to enhance therapeutic efficacy. We studied two strategies: PA-LJC nanostructures (Encapsulation) and PA nanostructures + free LJC (Combination). Computational modeling using a molecular theory for amphiphile self-assembly captures and explains the morphology of PA-LJC nanostructures and the location of encapsulated LJC in agreement with transmission electron microscopy and two-dimensional (2D) NMR observations. The morphology and release profile of PA-LJC assemblies are strongly correlated to the PA:LJC ratio: high LJC loading induces an initial burst release. We then evaluated the antimicrobial activity of our nanosystems toward gram-positive and gram-negative bacteria. We found that the Combination broadens the spectrum of LJC, reduces the therapeutic concentrations of both agents, and is not impacted by the inoculum effect. Further, the Encapsulation provides additional benefits including bypassing water solubility limitations of LJC and modulating the release of this molecule. The different properties of PA-LJC nanostructures results in different killing profiles, and reduced cytotoxicity and hemolytic activity. Meanwhile, details in membrane alterations caused by each strategy were revealed by various microscopy and fluorescent techniques. Last, in vivo studies in larvae treated by the Encapsulation strategy showed better antimicrobial efficacy than polymyxin B. Collectively, this study established a multifunctional platform using a versatile PA to act as an antibiotic, membrane-penetrating assistant, and slow-release delivery vehicle. [ABSTRACT FROM AUTHOR]

The dilute nanocomposite strategy facilitates a promising route for high-temperature polymer dielectrics to achieve high dielectric constant and energy density, robust breakdown strength, and low loss. The dielectric enhancement of the dilute nanocomposites strongly ties to the topological conditions of the nanofiller–polymer interface. Here, atomic force microscopy-based infrared spectroscopy was employed to observe the interfacial region of a high-temperature poly(arylene ether urea) (PEEU) dilute nanocomposite directly. The experimental results showed that the nanoparticles induce morphological changes in PEEU, and the interface region extends over 150 nm away from the nanofiller surfaces. Such nano-morphology changes are highly indicative of generating a large enhancement of the dielectric performance in the PEEU dilute nanocomposite. [ABSTRACT FROM AUTHOR]

Hybrid nanomaterials have found use in many biomedical applications. This article provides a comprehensive review of the principles, techniques, and recent advancements in the design and fabrication of hybrid nanomaterials for biomedicine. We begin with an introduction to the general concept of material hybridization, followed by a discussion of how this approach leads to materials with additional functionality and enhanced performance. We then highlight hybrid nanomaterials in the forms of nanostructures, nanocomposites, metal–organic frameworks, and biohybrids, including their fabrication methods. We also showcase the use of hybrid nanomaterials to advance biomedical engineering in the context of nanomedicine, regenerative medicine, diagnostics, theranostics, and biomanufacturing. Finally, we offer perspectives on challenges and opportunities. [ABSTRACT FROM AUTHOR]

Today, SF is a natural polymer with unique features, such as excellent mechanical properties, biocompatibility, biodegradability, and low toxicity, which characterize this material with diverse forms for different purposes. Silk nanoparticles, scaffolds, films, and mats are used in various therapeutic and diagnostic strategies including drug/gene delivery, tissue engineering, biomolecule detection, and wound healing. Therefore, a study that examines all SF applications and evaluates its toxicity helps researchers in future projects. In this study, we comprehensively searched all sources of databases in different years about the medical application of various types of SF. Also, we reviewed the toxicity of SF. Several newer papers were selected for reporting and conclusions. In conclusion, the evaluation of the literature revealed that SF is a promising candidate for a wide range of biomedical applications. [ABSTRACT FROM AUTHOR]