Magnetic-field-induced phase separation via spinodal decomposition in epitaxial manganese ferrite thin films.

In this study, we report about the occurrence of phase separation through spinodal decomposition (SD) in spinel manganese ferrite (Mn ferrite) thin films grown by Dynamic Aurora pulsed laser deposition. The driving force behind this SD in Mn ferrite films is considered to be an ion-impingement-enhanced diffusion that is induced by the application of magnetic field during film growth. The phase separation to Mn-rich and Fe-rich phases in Mn ferrite films is confirmed from the Bragg's peak splitting and the appearance of the patterned checkerboard-like domain in the surface. In the cross-sectional microstructure analysis, the distribution of Mn and Fe-signals alternately changes along the lateral (x and y) directions, while it is almost homogeneous in the z-direction. The result suggests that columnar-type phase separation occurs by the up-hill diffusion only along the in-plane directions. The propagation of a quasi-sinusoidal compositional wave in the lateral directions is confirmed from spatially resolved chemical composition analysis, which strongly demonstrates the occurrence of phase separation via SD. It is also found that the composition of Mn-rich and Fe-rich phases in phase-separated Mn ferrite thin films deposited at higher growth temperature and in situ magnetic field does not depend on the corresponding average film composition.

Impact of Methods of Preparation on Mechanical Properties, Dissolution Behavior, and Tableting Characteristics of Ibuprofen-Loaded Amorphous Solid Dispersions.

This study aims to improve the biopharmaceutical, mechanical, and tableting properties of a poorly soluble drug, ibuprofen (IBP), by preparing amorphous solid dispersion (ASD) followed by a sustained-release tablet formulation. A suitable polymer to develop an ASD system was chosen by utilizing the apparent solubility of IBP in various polymer solutions. ASDs containing various ratios of IBP and selected polymer were prepared by the melt fusion (MF) method. ASD containing optimized drug-polymer ratio prepared by freeze-drying (FD) method was characterized and compared physicochemically. The solubility of IBP in water increased 28-fold and 35-fold when formulated as ASD by MF and FD, respectively. Precise formulations showed amorphization of IBP and increased surface area, improving solubility. The dissolution pattern of optimized ASD-IBP in pH 6.8 phosphate buffer after 60 min in MF and FD was enhanced 3-fold. In addition, direct compression tablets comprising optimized ASD granules from MF and FD were made and assessed using compendial and noncompendial methods. ASD-IBP/MF and ASD-IBP/FD formulations showed a similar drug release profile. In addition, 12 h of sustained IBP release from the ASD-IBP-containing tablets was obtained in a phosphate buffer with a pH of 6.8. From the dissolution kinetics analysis, the Weibull model fitted well. The drug release pattern indicated minimal variations between tablets formed using ASD-IBP prepared by both procedures; however, pre- and postcompression assessment parameters differed. From these findings, the application of ASD and sustained-release polymers in matrix formation might be beneficial in improving the solubility and absorption of poorly soluble drugs such as IBP.

Growth, structural, thermal, and optical characteristics of L-asparagine monohydrate doped magnesium sulphate heptahydrate semiorganic crystals.

A novel semi-organic crystal has been grown using slow evaporation technique by doping organic compound L-asparagine monohydrate (C4H8N2O3·H2O) with inorganic material Magnesium sulphate heptahydrate (MgSO4·7H2O). The crystallographic parameters like strain, dislocation density and crystallite size were calculated by powder X-ray diffraction method. Functional groups were identified and bond length, force constants were calculated from FT-IR spectroscopy. Energy dispersive X-ray (EDX) analysis was used to identify the constituent elements of the crystal. Kinetic and thermodynamic parameters, such as, activation energy Ea, change in Gibb's free energy (ΔG) and change in enthalpy (ΔH) have been determined by thermogravimetric analysis (TGA) analysis. Ea, ΔH and ΔG show positive values and change in entropy (ΔS) shows negative ones. The thermal degradation behavior of the crystals has been analyzed by differential scanning calorimetry (DSC) analysis. Various optical constants such as optical band gap, lattice dielectric constant, absorbance, extinction coefficient, the ratio of free charge carrier concentration to the effective mass, Urbach energy, optical and electrical conductivities were estimated from UV-vis transmittance data. High optical conductivity (1010 s-1) justifies the good photo response nature of the semi-organic crystal.

Evaluation of chitosan-Ag/TiO2 nanocomposite for the enhancement of shelf life of chili and banana fruits.

Post-harvest losses of fruits and vegetables account for a large share of food waste in the world due to improper handling and packaging. By using the sol-gel method, Ag/TiO2 nanocomposite was prepared in this study from micro-sized commercial TiO2 powder and incorporated in a chitosan-cellulose matrix for the purpose of promising food packaging. The particle size and distribution of Ag nanoparticles (9.2437 nm size) confirmed their successful inclusion in the TiO2 surface. The morphology of the package assured the successful and uniform disbursement of Ag/TiO2 nanocomposite into the chitosan-cellulose matrix, which led to enhanced water resistance and photocatalytic activity. The developed package is proficient in hindering the growth of fecal coliform bacteria (Esche (Escherichia coli) by 9 mm in the agar plate. Moreover, the efficient application of chitosan-Ag/TiO2 nanocomposite in food coating and packaging was examined in extending shelf life, minimizing water loss, and preventing microbial infection during the storage of chili (up to 7 days at 37 °C) and banana, respectively. It can be concluded from the results that chitosan-Ag/TiO2 nanocomposite-based food coating and packaging have competent potential for enhancing the shelf life of moist foods.

Abundance, characteristics, and ecological risks of microplastics in the riverbed sediments around Dhaka city.

Microplastic (MP) pollution has become an escalating problem in Bangladesh due to its rapid urbanization, economic growth, and excessive use of plastics; however, data on MP pollution from fresh water resources in this country are limited. This study investigated microplastics pollution in riverbed sediments in the peripheral rivers of Dhaka, the capital of Bangladesh. Twenty-eight sediment samples were collected from the selected stations of the Buriganga, Turag, and Balu Rivers. Density separation and wet-peroxidation methods were employed to extract MP particles. Attenuated total reflectance-Fourier transform infrared spectroscopy was used to identify the polymers. The results indicated a medium-level abundance of MPs in riverbed sediment in comparison with the findings of other studies in freshwater sediments worldwide. Film shape, white and transparent color, and large-size (1-5 mm) MPs were dominant in the riverbed sediment. The most abundant polymers were polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Pollution load index (PLI) values greater than 1 were observed, indicating that all sampling sites were polluted with MPs. An assessment of ecological risks, using the abundance, polymer types, and toxicity of MPs in the sediment samples, suggested a medium to very high ecological risk of MP pollution of the rivers. The increased abundance of MPs and the presence of highly hazardous polymers, namely; polyurethane, acrylonitrile butadiene styrene, polyvinyl chloride, epoxy resin, and polyphenylene sulfide, were associated with higher ecological risks. Scanning electron microscopy (SEM) analysis indicated that the MPs were subjected to weathering actions, reducing the size of MPs, which caused additional potential ecological hazards in these river ecosystems. This investigation provides baseline information on MP pollution in riverine freshwater ecosystems for further in-depth studies of risk assessment and developing strategies for controlling MP pollution in Bangladesh.

A QbD Approach to Design and to Optimize the Self-Emulsifying Resveratrol-Phospholipid Complex to Enhance Drug Bioavailability through Lymphatic Transport.

Objectives: Despite having profound therapeutic value, the clinical application of resveratrol is restrained due to its <1% bioavailability, arising from the extensive fast-pass effect along with enterohepatic recirculation. This study aimed to develop a self-emulsifying formulation capable of increasing the bioavailability of resveratrol via lymphatic transport. Methods: The resveratrol−phospholipid complex (RPC) was formed by the solvent evaporation method and characterized by FTIR, DSC, and XRD analyses. The RPC-loaded self-emulsifying drug delivery system (SEDDS) was designed, developed, and optimized using the QbD approach with an emphasis on resveratrol transport through the intestinal lymphatic pathway. The in vivo pharmacokinetic study was investigated in male Wister Albino rats. Results: The FTIR, DSC, and XRD analyses confirmed the RPC formation. The obtained design space provided robustness of prediction within the 95% prediction interval to meet the CQA specifications. An optimal formulation (desirability value of 7.24) provided Grade-A self-emulsion and exhibited a 48-fold bioavailability enhancement compared to the pure resveratrol. The cycloheximide-induced chylomicron flow blocking approach demonstrated that 91.14% of the systemically available resveratrol was transported through the intestinal lymphatic route. Conclusions: This study suggests that an optimal self-emulsifying formulation can significantly increase the bioavailability of resveratrol through lymphatic transport to achieve the desired pharmacological effects.

Evaluation of a novel nanocrystalline hydroxyapatite powder and a solid hydroxyapatite/Chitosan-Gelatin bioceramic for scaffold preparation used as a bone substitute material.

Artificially fabricated hydroxyapatite (HAP) shows excellent biocompatibility with various kinds of cells and tissues which makes it an ideal candidate for a bone substitute material. In this study, hydroxyapatite nanoparticles have been prepared by using the wet chemical precipitation method using calcium nitrate tetra-hydrate [Ca(NO3)2.4H2O] and di-ammonium hydrogen phosphate [(NH4)2 HPO4] as precursors. The composite scaffolds have been prepared by a freeze-drying method with hydroxyapatite, chitosan, and gelatin which form a 3D network of interconnected pores. Glutaraldehyde solution has been used in the scaffolds to crosslink the amino groups (|NH2) of gelatin with the aldehyde groups (|CHO) of chitosan. The X-ray diffraction (XRD) performed on different scaffolds indicates that the incorporation of a certain amount of hydroxyapatite has no influence on the chitosan/gelatin network and at the same time, the organic matrix does not affect the crystallinity of hydroxyapatite. Transmission electron microscope (TEM) images show the needle-like crystal structure of hydroxyapatite nanoparticle. Scanning Electron Microscope (SEM) analysis shows an interconnected porous network in the scaffold where HAP nanoparticles are found to be dispersed in the biopolymer matrix. Fourier transforms infrared spectroscopy (FTIR) confirms the presence of hydroxyl group (OH-) , phosphate group (PO3- 4) , carbonate group (CO2- 3) , imine group (C=N), etc. TGA reveals the thermal stability of the scaffolds. The cytotoxicity of the scaffolds is examined qualitatively by VERO (animal cell) cell and quantitatively by MTTassay. The MTT-assay suggests keeping the weight percentage of glutaraldehyde solution lower than 0.2%. The result found from this study demonstrated that a proper bone replacing scaffold can be made up by controlling the amount of hydroxyapatite, gelatin, and chitosan which will be biocompatible, biodegradable, and biofriendly for any living organism.

In Vivo Toxicity Studies of Chitosan-Coated Cobalt Ferrite Nanocomplex for Its Application as MRI Contrast Dye.

Cobalt ferrite nanoparticle (CFN) has received attention in magnetic resonance imaging (MRI) as a promising contrast agent due to its higher saturation magnetization and magneto-crystalline anisotropy. However, the in vitro cytotoxicity of CFN has raised concern for its biomedical application as a diagnostic agent. The coating of CFN by a biocompatible polymer such as chitosan (CH) might lessen the biocompatibility concern. Therefore, in this study, we examined the applicability of chitosan-coated cobalt ferrite nanoparticle (CCN) as an MRI contrast dye and investigated its biocompatibility in vivo. Phantom MRI images revealed that the relaxivity of CCN was 121 (±8) mM-1s-1, indicating the potential of CCN as a T2-weighted contrast agent. A single intravenous (iv) administration of CCN (10 mg/kg) improved the contrast of magnetic-resonance-imaging-based angiography (MRA) and brain-MRI in male albino Wistar rats compared to the control. Furthermore, toxicity studies dependent on dose (1-20 mg/kg) and time (1-28 days) in male albino Wistar rats confirmed the in vivo biocompatibility of CCN. The physical, hematological, biochemical, and histopathological observation assured that a single iv injection of CCN up to 20 mg/kg was well adjusted with liver, kidney, heart, and brain functions. The findings of the current study consolidate CCN as a promising candidate for MRI contrast dye.