A Facile Microwave-Assisted Green Synthetic Approach of Solid-State Fluorescent Carbon-Dot Nanopowders Derived from Biowaste for Potential Latent-Fingerprint Enhancement

Latent fingerprint detection and visualization remains a challenge especially where problems of poor contrast, auto-fluorescent surfaces and patterned backgrounds are encountered. As a result there is an increasing interest in the development of simple, cost effective, rapid and yet accurate methods for latent fingerprint detection and recovery. Herein, this paper reports the synthesis of bright blue photoluminescent carbon dots (C-dots) via an eco-friendly and simple one-step microwave-assisted carbonization of potato peels’ biomass. The C-dots were prepared in only 3 min and ground into powder and used without any further treatment. The as-prepared C-dots were characterized using atomic force microscope, Fourier transform infra-red spectroscopy and X-ray diffraction with an average size of 1.0[Formula: see text]nm. The optical properties of the as-prepared C-dots were studied by UV-Vis spectroscopy and spectrofluorometer which established an excitation and emission wavelengths of 390[Formula: see text]nm and 480[Formula: see text]nm, respectively. Owing to their strong solid state fluorescence, the as-prepared C-dots’ powder was successfully used in latent fingerprint detection and imaging on porous and nonporous surfaces. Latent fingerprints were recovered with high resolution and excellent quality providing sufficient details for individual identification. These findings demonstrate that C-dots derived from biomass have a great potential in latent fingerprint analysis for forensic applications.

Synthesis of 2D Heterostructures: MOS2/GO and MOS2/Graphene via Microdrop and CVD Deposition

The main objective of this work was to study the synthesis and characteristics of two-dimensional heterostructures (2D/2D) using pure molybdenum disulfide (MoS[Formula: see text] and doped with phosphorus at 5% and 15% combined with graphene oxide (GO) and graphene monolayer. These were deposited on silicon and copper substrates using two different deposition methods: Microdrop casting and chemical vapor deposition. Chemical and structural information of the samples were characterized by Raman spectroscopy, Energy Dispersion X-ray Spectroscopy (EDS), Scanning Electron Microscopy (SEM) and Kelvin Probe Force Microscopy (KPFM). The results prove the synergy between the materials resulting in electronic coupling, making this system potential for applications in electronic devices such as sensors, resistors and capacitors.

Preparation of Gentamicin Sulfate Nanoparticles using Eudragit RS-100 and Evaluation of Their Physicochemical Properties

Improving permeability and absorption of drugs are critical research challenges in pharmaceutical science. Gentamicin sulfate is an aminoglycoside antibiotic, which is very active against gram-negative bacteria; however, it has very poor bioavailability. This study aimed to prepare gentamicin nanoparticles with the intention of increased bioavailability. Accordingly, Eudragit RS-100 nanoparticles loaded with gentamicin sulfate were prepared by the double emulsification and solvent evaporation method, a proper technique for encapsulating hydrophilic molecules. Nanoparticles’ suspensions with polymer to drug ratios of 1:1 ([Formula: see text] and 2:1 ([Formula: see text]) were prepared, lyophilized and evaluated for their production yield, physicochemical properties and morphology. The mean particle size was 195.67[Formula: see text]nm and 228[Formula: see text]nm for [Formula: see text] and [Formula: see text], respectively. The formulations’ loading efficiencies were relatively high (85.73 for [Formula: see text] and 85.20 for [Formula: see text]). The nanoparticles’ surface charge (+40.5[Formula: see text]mV) was sufficient to inhibit their aggregation and facilitate the nanoparticles’ absorption through the gastrointestinal tract. The results of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) revealed that drug and polymer stabilized each other by physical interactions between their functional groups. Both formulations presented an initial burst drug release of nearly 20% after 30[Formula: see text]min in phosphate buffer (pH = 7.4). After 24[Formula: see text]h, [Formula: see text] did not release the drug completely, while [Formula: see text] released the whole drug. Overall, nanoparticles with proper characteristics were obtained. This study puts forward the necessity of conducting further research in order to explore the intestinal absorption of these nanoparticles and the possibility of being utilized for oral administration of gentamicin sulfate.

Biocompatibility Evaluation of Hollow Pollen Grains/Fe3 O4 Nanoparticles Composites as Potential Medical Devices

Recently, pollen grains (PGs) have been introduced as drug carriers and scaffolding building blocks. This study aimed to assess the in-vitro biocompatibility of Pistacia vera L. hollow PGs/Fe3O4 nanoparticles (HPGs/Fe3O4NPs) composites using human adipose-derived mesenchymal stem cells (hAD-MSCs). In this regard, iron oxide nanoparticles (Fe3O4NPs) were assembled on the surface of HPGs at different concentrations. The biocompatibility of the prepared composites was assessed through MTT assay, apoptosis-related gene expression and field emission scanning electron microscopy (FE-SEM) analysis. Compared to the bare HPGs, the HPGs/Fe3O4NPs exhibited a biphasic impact on hAD-MSCs. The composite containing 1% Fe3O4NPs demonstrated no cytotoxicity up to 21 days while higher Fe3O4NPs contents and long-term exposure revealed adverse effects on the hAD-MSCs’ growth. The obtained result was verified by the qRT-PCR and morphological analysis carried out through FE-SEM which suggests that a narrow region below 1% Fe3O4NPs may be the optimum choice for medicinal applications of HPGs/Fe3O4NPs microdevices.

The Effect of Wear Rate on Polymeric Composites Reinforced Nanoclays

This research aims to study the addition of nanoclays on unsaturated polyester (UP) and epoxy resin (EP) as filling and by weight percentage (2%, 4% and 6%) to this mixture and then study the extent of the effect of this addition on wear rate of the composites’ material where three loads were adopted (10, 15 and 20[Formula: see text]N), respectively, on the iron hard disk (269 HB) and copper hard disk of 111[Formula: see text]HB for the resin before and after adding the clays, where the approved sliding velocities were 4.1887, 3.1415 and 2.0943[Formula: see text]m/sec, respectively, and the test duration was 10 min on the test disc. Immersion of samples in the water for 2, 4, 6 and 8 weeks showed a clear improvement in the wear rate and tear values of dry and submerged conditions in a water under different conditions of load change, slipping speed, time and temperature stability after adding the nanoclays to the polymer.

Synthesis and Characterization of NiFe2O4 Magnetic Nanoparticles for Magnetic Resonance Imaging Application

NiFe2O4 magnetic nanoparticles (MNPs) were synthesized by co-precipitation of iron (III) chloride hexahydrate and nickel (II) chloride hexahydrate in the solution containing 45% hydrazine at 80∘C. Phase, morphology, oxidation state and magnetic properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM). In this research, pure NiFe2O4 MNPs synthesized in the solution with the pH of 10 with saturation magnetization of 49.839[Formula: see text]emu/g were detected and were able to be used for magnetic resonance imaging (MRI) application with very high contrast. Highlights:[Formula: see text] NiFe2O4 is used as magnetic nanoparticles. [Formula: see text] They have an excellent saturation magnetization. [Formula: see text] The promising material is used for magnetic resonance imaging application.

Kinetics and Adsorption Model of Methylene Blue on [email protected] Nanoplate Composite

[email protected] nanoplate composite adsorbents were prepared in a simple acid precipitation method at room temperature. The [email protected] nanoplate composite adsorbents were characterized by X-ray powder diffraction, micro-Raman spectroscopy, Fourier transform infrared spectra, scanning electron microscopy and UV-vis diffuse reflectance spectroscopy. The results show that the orthorhombic-phase WO3.H2O nanoplates with dimensions of [Formula: see text][Formula: see text]nm3 were successfully composited with g-C3N4. The methylene blue dye generation activity of these adsorbents was evaluated. The kinetics and absorption model of [email protected] nanoplate composite adsorbents were further studied.

Suitability of Iron (Fe)-Doped Tungsten Oxide (WO3) Nanomaterials for Photocatalytic and Antibacterial Applications

Pure and “Fe ([Formula: see text][Formula: see text]wt.%)-doped” WO[Formula: see text] nanoparticles were prepared by facile microwave irradiation method and that was investigated for strong photo catalytic and antibacterial activity applications for the first time. The primary aim of this work is to reveal the great importance of oxygen vacancies ([Formula: see text] due to dopant (Fe[Formula: see text] for photo catalytic and antibacterial activity applications. This work also discusses the contribution of oxygen vacancies and their dependence on surface area and phase formation which are of great research interest for water purification and biological sciences. Herein, pure and “Fe ([Formula: see text][Formula: see text]wt.%)-doped” WO[Formula: see text] nanoparticles were successfully synthesized by facile microwave irradiation (MWI) method (2.45 GHz/240W/10min) in ambient atmosphere. The phase formation and the crystalline nature of the prepared products were evaluated using powder X-ray diffraction (XRD). It confirmed the phase formation of orthorhombic and monoclinic phase formations for the pure (WO[Formula: see text]H2O) and annealed samples (W[Formula: see text]O[Formula: see text] and WO[Formula: see text], respectively. Optical behavior of the samples from UV-Vis diffuse reflectance analysis revealed that W[Formula: see text]O[Formula: see text] has remarkable bandgap values (1.96[Formula: see text]eV) that clearly emphasizes the transfer of oxygen ions which helps in the movement of oxygen vacancies inside the crystalline domain. The morphological nature of the prepared products was observed by FE-SEM analysis and the average dimension was found to be 0.2–3.2[Formula: see text][Formula: see text]m and 2–4[Formula: see text][Formula: see text]m for the pure and annealed products, respectively. The specific surface area from BET analysis explored that W[Formula: see text]O[Formula: see text] having 55.16[Formula: see text]m2g[Formula: see text] was found to be higher than that of commercially available WO3. The photocatalytic behavior of the prepared compounds morphologies was investigated via Rhodamine B (RhB) degradation under visible light irradiation. These results showed “Fe-doped” annealed WO3 nanoparticles have degradation efficiency of 86.9% along with high stable nature. On the other hand, to identify the suitability of the prepared products for antibacterial activity, the microbial strains of Gram-positive Bacillus sp. and Gram-negative strains of Pseudomonas sp. and Salmonella sp. were used for the antimicrobial assay[Formula: see text] The results indicated that W[Formula: see text]O[Formula: see text] showed enhanced antibacterial nature when compared to that of Stoichiometry tungsten oxide (WO[Formula: see text] nanomaterials. From these observations, this work emphasizes the importance of oxygen vacancies for antibacterial activity applications.

Laser-Induced Plasma Atomic and Ionic Emission During Target Ablation

This paper investigates the spectroscopy of plasma that resulted from the bombardment of ZnSe by using the optical emission spectroscopic (OES) technique. The plasma can be generated by the reaction between an Nd:YAG laser, with a wavelength of 1064[Formula: see text]nm with a repeat rate of 6[Formula: see text]Hz (as well as 9[Formula: see text]ns pulse duration), and a solid target, where the density of the electron (ne), the temperature of the electron ([Formula: see text]), the frequency of the plasma ([Formula: see text]) and the Debye length ([Formula: see text]) as plasma parameters, in addition to the particles’ number of Debye ([Formula: see text]) and plasma parameter ([Formula: see text]) have been calculated by picking up the spectrum of plasma at different energies (100, 200, 300, 400, 500) mj using Selenium (Se), Zinc (Zn) and the mixture (ZnSe) at ([Formula: see text]). It is found that the electron temperatures of Zn and Se ranged between (0.257–0.267)[Formula: see text]eV and (1.036–1.055) eV, respectively, while that of ZnSe ranged between (1.15–1.28)[Formula: see text]eV. This indicates that the electron temperature of ZnSe is higher than the temperatures of each Zn and Se.

Synthesis and Antibacterial Activity of Silver Nanoparticles Against Escherichia coli and Pseudomonas sp.

Silver nanoparticles (AgNPs) have been synthesized by chemical reduction method using ascorbic acid as reducing agent. Silver nitrate (AgNO[Formula: see text] and sodium dodecyl sulfate (SDS) have been used as precursor and stabilizer, respectively. The prepared samples were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The antibacterial activity of prepared silver nanoparticles has been assessed by using the disc diffusion method against pathogenic, gram-negative bacterial strains including Escherichia coli and Pseudomonassp. To evaluate the potential antibacterial properties of AgNPs, the discs have been impregnated and dried with three different doses like 50, 100 and 150[Formula: see text][Formula: see text]l of 20[Formula: see text][Formula: see text]g/ml concentrated AgNPs solution and placed on the Petri-dishes. The antibiotic kanamycin (5[Formula: see text][Formula: see text]g) was used as control. In all the cases, a clear and distinct zone of inhibition is observed, which suggests that AgNPs can be used as effective growth inhibitors of various bacterial species and would be promising candidate for future development of antibacterial agents.