Preparation of Semi-Solid 357.0 Slurries with Different α-Al Phase Features by Solidification from Full Liquid State and Remelting

The characteristics of the solid phase, namely the volume fraction, particle size, and morphology, are dominant variables that can determine the viscosity of the semi-solid slurry. However, particle size and morphology were always being ignored and the solid fraction was simply determined using the temperature in the conventional power-law viscosity, resulting in a disagreement in the viscosity values in different researches. To make the power-law viscosity model more accurate for predicting the filling process of semi-solid die casting, it is essential to modify this viscosity model based on particle characteristics. Therefore, there is a fundamental demand to prepare semi-solid slurries with different α-Al phase features at first. This is achieved in this study by two kinds of heat history controlling methods: remelting and solidification, which can get slurries with spherical structure and dendric structure, respectively. The semi-solid 357.0 slurries with 0.11-0.43 solid fraction, 137-182μm particle size, and 0.81-0.90 shape factor were prepared in the remelting process, while dendritic structures (shape factor<0.5) with 0.1 and 0.3 solid fractions were obtained by solidification controlling from the full liquid state. Besides, the effect of parameters on the evolution of the α-Al phase has been discussed. These slurries with different solid features will be further used to quantify the influence of primary phase characteristics on rheological behavior and make the power-law viscosity model more accurate for simulation.

Improved Anti-Washout Property of Calcium Sulfate/Tri-Calcium Phosphate Premixed Bone Substitute with Glycerin and Hydroxypropyl Methylcellulose

Calcium sulfate/calcium phosphate (CS-CP)-based bone substitutes have been developed in premixed putty for usage in clinical applications. However, it is difficult to completely stop the bleeding during an operation because premixed putty can come into contact with blood or body fluids leading to disintegration. Under certain conditions depending on particle size and morphology, collapsed (washed) particles can cause inflammation and delay bone healing. In this context, anti-washout premixed putty CS-CP was prepared by mixing glycerin with 1, 2, and 4 wt% of hydroxypropyl methylcellulose (HPMC), and the resultant anti-washout properties were evaluated. The results showed that more than 70% of the premixed putty without HPMC was disintegrated after being immersed into simulated body fluid (SBF) for 15 min. The results demonstrated that the more HPMC was contained in the premixed putty, the less disintegration occurred. We conclude that CS-CP pre-mixed putty with glycerin and HPMC is a potential bone substitute that has good anti-washout properties for clinical applications.

Biosynthesis of 3D/2D Ceo2/Mos2 Nanocomposites with Enhanced Photocatalytic Activity to Degrade Organic Dye in Wastewater and Statistical Optimization of Reaction Parameters

Nanocomposites synthesized by alternative approaches like biosynthetic methods are safer than those prepared by traditional chemical techniques. Further, this approach is both economically and environmentally feasible. In this study, we report an eco-friendly methodology for preparing cerium dioxide/molybdenum disulphide (CeO2/MoS2) nanocomposites. Moringa oleifera peel was used as the reducing/stabilizing agent for synthesizing CeO2 nanoparticles. The prepared nanocomposite were characterized using FT-IR analysis, SEM and EDAX analysis, TEM and SAED pattern analysis, X-Ray Diffraction Pattern, Zeta Potential, UV-Visible Diffuse Reflectance Spectra, X-Ray Photon Spectroscopy and Photoluminescence spectra. Particle size and morphology were characterized by TEM and SEM. The photocatalytic pursuit of CeO2/MoS2 was explored by the degradation of methyl violet (MV) under visible light irradiation. Our methodology proved to be 96.25% effective in the degradation of MV. Further, we used this Response Surface Methodology for enhancing the process factors like volume of photocatalyst, time for degradation and concentration of MV.

Honokiol-Based Nanomedicine Decorated with Ethylene Glycols Derivatives Promotes Antitumor Efficacy

Honokiol-loaded nanoparticles (HK-loaded NPs) exhibit potential antitumor activity; however, the factors affecting their antitumor efficacy are still unclear and need to be explored. This research was aimed to systematically estimate the influence of feed weight ratio (FWR) and nanocarrier structure on antitumor activity. Accordingly, three types of ethylene glycol derivatives, including linear poly(ethylene glycol) with molar mass of 2000 (PEG45), first and second generation oligo(ethylene glycol) dendrons (G1 and G2) were used as nanocarriers, and a series of HK-loaded NPs with different FWR were prepared successfully using the evaporation-ultrasonication method. These NPs showed similar stability but demonstrated differences with respect to particle size, morphology, cumulative profile, and antitumor efficacy. The influence of the FWR was studied using G1 dendrons as nanocarriers; the results indicated that the particle size and morphology of G1 NPs were significantly affected, and G1 NPs (8/1), with the FWR of 8/1 for HK versus G1 dendron, exhibited the highest antitumor activity among all G1 NPs. Furthermore, the influence of nanocarrier structure was investigated at the FWR of 4/1; the findings revealed reduction in the particle diameter from 280 nm to 109 nm and change in morphology from sphere to flower-like structure with an increase in the branch degree from linear to dendron. Moreover, G2 NPs (4/1), with the FWR of 4/1 for HK versus G2 dendron, carrying the highest branch degree exhibited the greatest antitumor efficacy among all. These results are suggestive of influence of particle size and morphology on antitumor efficacy of HK-loaded NPs. Conclusively, this study demonstrated nanocarrier structure and the FWR significantly affect the antitumor efficacy of NPs, which should be optimized for designing nanoscale delivery systems.

Effect of precursor particle size and morphology on lithiation of Ni0.6Mn0.2Co0.2(OH)2

In this paper, Ni0.6Mn0.2Co0.2(OH)2 precursors with several different morphologies and particle sizes are mixed with Li2CO3 and heat treated for 5, 7.5 and 10 h. The effects of the precursor properties on the degree of lithiation, electrochemical properties and volumetric capacities of lithiated product are compared. Based on the characterization results, a small (3 μm), narrow span precursor can be lithiated in a short period of time (5 h) and has good initial discharge capacity (185 mA h g− 1) and capacity retention (93% for 55 cycles). In contrast, a large wide-span precursor requires over 10 h for full lithiation. A highly porous precursor can be lithiated faster than traditional large wide-span materials, and has low cation mixing and good crystallinity. However, the volumetric energy density of porous material is low after lithiation compared to the other tested materials. Capacity retention after washing correlated with crystallographic properties of the sample. Graphic abstract

Dehumidified Air-Assisted Spray-Drying of Cloudy Beetroot Juice at Low Temperature

This paper discusses the physicochemical properties of powders obtained by spray drying of cloudy beetroot juice, using dehumidified air in variants with or without carriers. The inlet air temperature was 130 °C or 90 °C, and the addition of the carriers was at a ratio of juice to carrier solids of 3:2. In the obtained powders, the following physicochemical properties were determined: water content and water activity, apparent density, loose and tapped density, porosity, flowability, particle size and morphology, and the content and retention of betalains. It was possible to dry cloudy beetroot juice without the use of carriers at low temperatures (90 or 130 °C). The 100% beetroot powders were characterized by satisfactory physicochemical properties, often better than those with carriers (including lower hygroscopicity and higher color saturation and yield). A lower loss of betalains was found for the powders with the addition of carriers. The best process yields were obtained for the powder without carriers at 130 °C and 90 °C.

Synthesis and Characterization of a Fe3O4@PNIPAM-Chitosan Nanocomposite and Its Potential Application in Vincristine Delivery

In this research, we conducted a systematic evaluation of the synthesis parameters of a multi-responsive core-shell nanocomposite (Fe3O4 nanoparticles coated by poly(N-isopropylacrylamide) (PNIPAM) in the presence of chitosan (CS) (Fe3O4@PNIPAM-CS). Scanning electron microscopy (SEM) was used to follow the size and morphology of the nanocomposite. The functionalization and the coating of Fe3O4 nanoparticles (Nps) were evaluated by the ζ-potential evolution and Fourier Transform infrared spectroscopy (FTIR). The nanocomposite exhibited a collapsed structure when the temperature was driven above the lower critical solution temperature (LCST), determined by dynamic light scattering (DLS). The LCST was successfully shifted from 33 to 39 °C, which opens the possibility of using it in physiological systems. A magnetometry test was performed to confirm the superparamagnetic behavior at room temperature. The obtained systems allow the possibility to control specific properties, such as particle size and morphology. Finally, we performed vincristine sulfate loading and release tests. Mathematical analysis reveals a two-stage structural-relaxation release model beyond the LCST. In contrast, a temperature of 25 °C promotes the diffusional release model. As a result, a more in-depth comprehension of the release kinetics was achieved. The synthesis and study of a magnetic core-shell nanoplatform offer a smart material as an alternative targeted release therapy due to its thermomagnetic properties.

Impact of particle size and morphology of cobalt oxide on the thermal response to methane examined by thermal analysis

Differential thermal analysis (DTA) was used to examine the effect of the particle size and morphology of cobalt (III/IV) oxide (Co3O4) on its thermal response under exposure to methane (1 vol % in dry synthetic air), which is a relevant gas for the detection of combustible gases. The DTA response results from the catalytic oxidation of methane, and its characteristics should correlate with the pellistor response. Co3O4 samples differing in particle size and morphology were produced by ball milling (top-down technique) or were synthesized from precursor molecules by precipitation (bottom-up technique). The investigations carried out in dry air and a temperature range between 250 and 450 ∘C reveal that both particle size and particle shape have a considerable effect on thermal response, since the resulting layer structures and the associated surface area available for gas interaction differ. The Co3O4 catalyst, with small particles and an irregular shape, exhibits significantly higher response than milled Co3O4 samples. Comparison of DTA with the mass spectroscopy signal of CO2 evolved by the reaction verified a certain analogy between DTA measurements and the response produced by a pellistor.