Next Nanotechnology最新文献

During the COVID-19 pandemic, the mandatory use of multiple surgical masks or N95 respirators in public raised concerns about potential health issues associated with the increased breathing force needed to maintain the breathing cycle. To address these concerns, we conducted a comprehensive study investigating the transportation and filtering mechanisms of heterogeneous nanoparticles and virus-like particles through surgical masks and N95 respirators. Our multifaceted approach combined in vitro experiments utilising aerosol spray paints containing nanoparticles and in vivo validation on human volunteer inhaling city air. We employed scanning electron microscopy and transmission electron microscopy to analyse the distribution of nanoparticles across various mask layers and pristine silicon substrates placed on human skin. In addition, we provide analytical insights into the pressure distribution and fluid velocity profiles within the complex polymer fibre network of the masks. Our findings remarkably revealed that both single surgical masks and N95 respirators exhibited similar nanofluidic performance in filtering colloidal and jet-stream nanoparticles in the air. These results have significant implications for policymakers in developing regulations to manage airborne pandemics and air pollution control, ultimately enhancing public health and safety during respiratory health crises.

This study utilized blue-light epitaxial wafers and employed semiconductor processes such as maskless laser writing, dry etching, wet etching, passivation layer deposition, electron beam evaporation, and ion implantation to fabricate micro-light emitting diode (μLED) arrays with different pixel sizes but the same emitting area (900 μm²). The μLED arrays with single pixel sizes of 5 μm, 10 μm, and 15 μm were fabricated, with array numbers of 6×6, 3×3, and 2×2, respectively. This study proposes etching the material in the channel region while retaining a certain width for implantation, known as the sidewall ion implantation process, aiming to achieve better insulation characteristics by using ion implantation technology to insulate the sidewall regions. It involves ion bombardment of the defect areas generated after plasma etching and the use of a passivation layer for protection. The isolation characteristics of μLED arrays processed by sidewall implantation exhibited better electrical isolation than those of μLED arrays processed only by plasma. The light output power, external quantum efficiency, and wall-plug efficiency were all superior for the sidewall implantation process when the device was miniaturized to 5 μm. Overall, the sidewall implantation process combined with plasma dry etching effectively improved the light output characteristics, with the enhancement ratio increasing as the device was miniaturized.

Nano bacterial cellulose (NBC) being a biopolymer has unique physical and chemical properties with high biocompatibility. It is pure cellulose with nanometer size, produced by certain group of bacteria. Its properties can be further improved by combining with poly(vinyl alcohol) (PVA), which is a fascinating polymer soluble in water and biocompatible. Composite films of PVA and NBC were prepared by solution casting method. Composite films of PVA-NBC (0,1,2,3,4,5 %) were tested for major packaging properties like water vapor transmission rate, swelling measurement, film solubility and moisture retention capacity. Among all concentration films, film with 5 % NBC- PVA showed better results for all the tests. Films were also checked for antimicrobial properties against spoilage-causing bacteria and fungi. Further, the films were applied to study the shelf life in the Mitli Banana (Musa sp.) followed by Organoleptic evaluation during storage. Results showed that the banana packed with 5 % NBC- PVA film has retained maximum acceptable characters than other packages.

The work focuses on the development of a hybrid nanofluid (NF) comprising zinc oxide-graphene (ZG) to address heat transfer (HT) limitations in thermal systems. The study employs a highly sensitive mode-mismatched dual-beam thermal lens (MDTL) method to analyze the lattice dislocation-induced thermal diffusivity (D) modifications of the hybrid NF. The hybrid composite (HC) is synthesized by solid-state mixing and annealing of ZG. The formation of ZG hybrid composites is revealed through X-ray diffraction (XRD), Fourier transform infrared, X-ray photoelectron, and Raman spectroscopic analyses. The structural dislocations present in the HC are understood from XRD and Raman analyses. Ultraviolet-visible and photoluminescence spectroscopic studies revealed the optical properties of the samples. The MDTL study is carried out by preparing the NFs of the synthesized samples in the base fluid, ethylene glycol (EG), and reveals the impact of crystallite defects on the thermal characteristics of the synthesized composites. Thus, the study suggests the potential capability of ZG composites in tuning the thermal behaviour of EG for HT applications.

NiO nanoparticles were synthesized using jasmine flower and orange peel. The transition from cubic to rhombohedral phase was observed with peak splitting in the XRD patterns as the annealing temperature increased. Differences in the annealing environment resulted in particles with different crystallite sizes and amounts of nickel vacancy, directly impacting their magnetic properties. Notably, particles below 30 nm exhibited weak ferromagnetism, while those above 30 nm showed antiferromagnetic properties. Moreover, the power of the laser was tuned to 5 mW to achieve the disappearance of the 2 M peak. A key highlight of this work is the identification of the transverse acoustic phonon mode and the splitting of the transverse optical (TO) mode in NiO.

Metal nanoparticles have a noteworthy future in cancer treatment research because of their smaller size and large active surface area. Though gold, silver, platinum, palladium, copper, zinc, iron and several other metal nanoparticles have been explored for their anticancer potential in different pathways, the main limitation of these particles is their toxicity which may be controlled through their size, surface modification and route of administration. Compared to other metal nanoparticles, ruthenium nanoparticles have high bio compatibility and they exhibit excellent photo-thermal effect. Though there are several reports in the literature on the anticancer potential of ruthenium complexes, ruthenium nanoparticles are not much investigated. In the present work, therefore, an attempt has been made to synthesize ruthenium nanoparticles in an easy and eco-friendly way using Aloe vera gel. Ruthenium chloride was used as a precursor and Aloe vera gel acted both as reducing and capping agent. The synthesized ruthenium nanoparticles were characterized using UV-Visible spectrophotometry, Fourier Transform Infrared Spectroscopy (FT-IR), High Resolution Transmission Electron Microscopy (HRTEM), Powder X-ray Diffraction (PXRD), Dynamic Light Scattering (DLS) and Field Emission Scanning Electron Microscopy (FESEM). The analyses confirmed the formation of nano globules of Aloe vera gel of diameter in the range 90–300 nm with ruthenium nanoparticles of average size 1.5 nm embedded in them. The synthesized Ru nanoparticles embedded in the nano globules of Aloe vera gel (ALV RuNPs) were explored for their anticancer potential in the Dalton's lymphoma ascites (DL) cell line using Trypan Blue assay. The results of the assay showed that the ALV RuNPs can induce concentration dependent cytotoxicity in DL cancer cells. Approximately 40 % cytotoxicity was obtained for concentration range 5–50 mg/mL of the sample while negligible cytotoxicity was observed for healthy PBMC cells. Theoretical study indicates significant interaction between the components present in Aloe vera and Ru-nanoparticles. The results showed that ruthenium nanoparticles can emerge as a promising bio-compatible candidate with the ability to selectively target cancer cells while sparing normal cells.

The growing interest in the utilization of natural plant-derived products, particularly essential oils as eco-friendly agrochemicals has spurred the consumer demand for clean-label products. Due to their robust antimicrobial and pesticidal properties, essential oils (EOs) exhibit significant potential in food preservation and agricultural applications. However, the poor aqueous stability and highly volatile nature of EOs limit their potential for practical applications in their pure form. In response, nanoemulsions (NEms) have emerged as promising delivery vehicles for EOs, offering advantages such as smaller size, high solubilization capacity, excellent encapsulation efficiency, and controlled release characteristics.

Here we review the recent advancements in the fabrication, optimization, and stability of EO NEms. The present article provides an in-depth exploration of all the currently available high-energy (ultrasonication, micro fluidization, high-pressure homogenization, rotor-stator mixer) and low-energy (spontaneous emulsification, phase inversion composition, emulsion inversion point, phase inversion temperature) methods being used for the fabrication of NEms and the respective advantages and disadvantages associated with them. Additionally, the review discusses various destabilization mechanisms such as Ostwald ripening, coalescence, etc. that generally impact essential oil NEms, providing a comprehensive understanding of the challenges associated with their stability. Furthermore, the review focuses on the recent practical applications of NEms in the sector of food preservation, flavoring agents, and sustainable agricultural practices.

Chloride and fluoride are very reactive water contaminants that have adverse effects on animal health as well as their psychochemical processes. The sensing of these two anions in an aqueous medium is important for clinical diagnosis, environmental monitoring, and various industrial applications. In this report, the stable colloid of gold nanoparticles functionalized (AuNPs) with 2-quinonimine (2-QI) was successfully synthesized to be used in the colorimetric sensing application of chloride and fluoride ions in an aqueous medium. A decrease in intensity of the Surface Plasmon Absorption (SPR) band in UV–VIS spectra was observed for colloids of AuNPs functionalized with 2-QI upon a gradual increase in the concentration of chloride or fluoride ions with respect to the water dilution. Though the intensity of the SPR band was found to decrease in the pH range of 2–12, the best result was observed at pH 2. A linearity range was observed up to 0.04 mM concentration of both the analyte for 880 μM AuNPs with sensitivity of ∼18–20 mM⁻¹ and a limit of detection of ∼8–8.5 μM. An immediate selective decolorization was observed by the naked eye for 0.5 mL of 160 μM AuNPs in a 0.5 mL aqueous chloride solution of 15 mM and fluoride solution of 17.5 mM. The responses were found to be selective over the other common cations, anions, or biomolecules tested. The proposed sensing mechanism was explained as the accumulation of AuNPs in micro-particles by destroying the stabilization of AuNPs through dipolar interaction with 2-QI.

Sensible thermal storage ceramics in the form of the fluid-bed show good competency on dealing with the intermittency of renewable energy and improving energy utilization efficiency by integration the functions of thermal absorption and storage. In-situ nano-sized β-Sialon whiskers reinforced Al₂O₃-based ceramic materials for fluid-bed thermal storage system were one-step synthesized by aluminothermic reduction method, using solid waste coal-series kaolin and Al powder as main raw materials and firing at 1500 °C in N₂ atmosphere. The effects of Al content and firing temperature on phase evolution, microstructure and properties of fired samples were researched by XRD, SEM, TEM, etc. The results showed that nano-sized β-Sialon whiskers could be in-situ synthesized at 1300 °C, which effectively enhanced the bending strength of fired samples. The highest β-Sialon content and the optimal properties could be achieved at 1500 °C while coal-series kaolin and Al mass ratio was equal to 70∶30, which were listed as follows: 30.7 % β-Sialon content, 74.9 MPa high-temperature bending strength (at 1400 °C), 6.17 × 10^-6·°C^-1 thermal expansion coefficient (room temperature-1000 °C), 0.74 J·(g·K)^-1 specific heat capacity (at room temperature), 873.90 kJ·kg^-1 theoretical thermal storage density (ΔT=900 °C), which is suitable as the thermal storage material for the fluid-bed thermal storage system.