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Crystallization is an experimental phenomenon that does not always depend on predicted data for efficient processing. It, therefore, becomes important to conduct experiments in the seeded or unseeded crystallization process to gain insight into the growth kinetic parameters. The knowledge of the process and kinetic parameters is proved useful in developing strategies for the optimal design of crystallizers and in control of crystal size distribution. A differential scanning calorimeter (DSC) was used to perform isothermal growth experiments for seeded crystallization, and the kinetics was evaluated using a de-supersaturation curve. In order to get the de-supersaturation curve, the DSC heat flow signal was used to measure and quantify the mass change of seeds during the crystal growth process as a function of time at a particular temperature. Experiments were performed at temperatures ranging from 10 to 40 °C in sealed DSC pans. The growth order g was calculated from the isothermal experiments at varying temperatures, and the mass growth rate coefficient Kg, linear growth rate coefficient kg, mass rate of crystal growth RG and activation energy Ea of benzoic acid in the ethanol–water binary solvent were estimated from growth order g. The kinetic parameters were compared with the data obtained using online measurement techniques and found to be in good agreement. The present work establishes the reliability of calorimetric transformation studies for estimating growth kinetics using a small amount of sample in a very short period, at higher temperatures and pressures. [ABSTRACT FROM AUTHOR]

The fabrication of magnetic carbon nanostructures is emerging to develop composites with unique properties. Consolidating magnetic nanoparticles with carbon materials can be used in nanoelectronics, catalysis, optical application, biosensors, environmental remediation, energy, hydrogen storage, drug transport, magnetic resonance imaging and cancer diagnosis. In addition, thermochemical methods such as hydrothermal carbonization and pyrolysis are low energy processes that offer an efficient synthesis of the controlled morphology of magnetic carbon nanocomposite. These methods provide chemical and morphological improvements of the structure, such as high surface area, ordered nanosizes, crystal matrix, material stability, electrical conductivity, magnetic saturation and coercivity. This paper reviews the fabrication and properties of magnetic carbon nanocomposites. [ABSTRACT FROM AUTHOR]

Triple negative breast cancer (TNBC) is an aggressive sub-type of breast cancer that rarely responds to conventional chemotherapy. Therefore, novel agents or new routes need to be developed to improve treatment efficacy and diminish severe side-effects of anti-cancer agents in TNBC patients. This study explores a novel localized co-delivery platform with potential application against TNBC. Uniform core-shell microparticles encapsulating cisplatin (Cis-DDP) and paclitaxel (PTX) are fabricated using coaxial electrohydrodynamic atomization technique and subsequently are embedded into an injectable hydrogel. The hydrogel provides an additional diffusion barrier against Cis-DDP and confines premature release of drugs. In addition, the hydrogel can provide a versatile tool for retaining particles in the tumor resected cavity during the injection following debulking surgery and prevent surgical site infection due to its inherent antibacterial properties. The combination of Cis-DDP and PTX demonstrates a synergistic effect against MDA-MB-231 cell line assigned to three different mechanisms of action, including denaturation of DNA strands, stabilization of microtubules, and amplification of intracellular reactive oxygen species (ROS) and activation of caspase-3 pathways. The results show a significant accumulation of mitochondrial ROS insults in cells upon treatment that consequently causes programmed cells death. The performance of microparticles/hydrogel carrier is evaluated against three-dimensional MDA-MB-231 (breast cancer) 3D spheroids, where a superior efficacy and a greater reduction in spheroid growth are observed over 14 days, as compared with free-drug treatment. Overall, drug-loaded core-shell microparticles embedded into injectable hydrogel provides a promising strategy to treat aggressive cancers and a modular platform for a broad range of localized multidrug therapies customizable to the cancer type. [ABSTRACT FROM AUTHOR]

The tumor suppressor protein p53 is the most frequently inactivated, mutated, or deleted transcriptional factor in tumor cells. Recent studies have shown that the negative regulation of p53 by the murine double minute 2 (MDM2) protein in human cells interrupts the p53 apoptotic pathway and causes tumorigenesis. Therefore, the disruption of the MDM2–p53 complex by small molecules such as nutlin-3a and the administration of the active p53 protein can effectively restore the apoptotic activity of the p53 protein in tumor cells. This study aims to introduce a unique combined p53-based gene and chemotherapy approach using core–shell polymeric microparticles for the localized treatment of cancers. Core–shell microparticles were successfully fabricated in a single step using a modified electrohydrodynamic atomization (EHDA) technique, where the core and shell layers were loaded with nutlin-3a and β-cyclodextrin-g-chitosan/p53 nanoparticles, respectively. The grafting of β-cyclodextrin (β-CD) onto chitosan chains demonstrated remarkable cellular uptake (∼5-fold) compared to pure chitosan at N/P = 6, attributed to a strong interaction and temporary disruption of the lipid bilayer in the cell membrane by the synthesized copolymer. The therapeutic efficiencies of single- and dual-agent loaded microparticle formulations were also evaluated and compared against free-drug treatment in terms of cell viability and intracellular expression of p53, caspase 3, and MDM2 proteins via an MTS assay, an enzyme-linked immunosorbent assay, and an immunostaining assay. The results revealed that the controlled and sustained release of both agents from the microparticles synergistically enhanced the anti-proliferative efficacy of the agents via the continuous overexpression of p53 and caspase 3 proteins over 5 days. However, MDM2 protein expression remained at the basal level over that period. The findings also indicated that nutlin-3a could impose excessive oxidative stress on cancer cells, where the overproduction of reactive oxygen species (ROS) with irreversible destructive effects on subcellular organelles such as the nucleus (DNA) and mitochondria could be considered as a secondary apoptotic pathway induced by nutlin-3a. Inspired by the observations, the proposed drug delivery system can serve as a unique and powerful drug and gene delivery system with a far-reaching application in human cancer therapy. [ABSTRACT FROM AUTHOR]

This is the first report of the utilization of TiNb2O7 as an insertion-type anode in a lithium-ion hybrid electrochemical capacitor (Li-HEC) along with an activated carbon (AC) counter electrode derived from a coconut shell. A simple and scalable electrospinning technique is adopted to prepare one-dimensional TiNb2O7 nanofibers that can be characterized by XRD with Rietveld refinement, SEM, and TEM. The lithium insertion properties of such electrospun TiNb2O7 are evaluated in the half-cell configuration (Li/TiNb2O7) and it is found that the reversible intercalation of lithium (≈3.45 mol) is feasible with good capacity retention characteristics. The Li-HEC is constructed with an optimized mass loading based on the electrochemical performance of both the TiNb2O7 anode and AC counter electrode in nonaqueous media. The Li-HEC delivers very high energy and power densities of approximately 43 Wh kg−1 and 3 kW kg−1, respectively. Furthermore, the AC/TiNb2O7 Li-HEC delivers a good cyclability of 3000 cycles with about 84 % of the initial value. [ABSTRACT FROM AUTHOR]