High temperature X-ray diffraction and thermo-gravimetrical analysis of the cubic perovskite Ba0.5Sr0.5Co0.8Fe0.2O3-δ under different atmospheres

Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) with the cubic perovskite structure is known to be metastable at low temperature under an oxidizing atmosphere. Here, the thermal and chemical expansion of BSCF were studied by in situ high temperature powder X-ray diffraction and thermo-gravimetrical analysis (TGA) in partial pressure of oxygen ranging from an inert atmosphere (∼10−4 bar) to 10 bar O2. The BSCF powder, heat treated at 1000 °C and quenched to ambient temperature prior to the analysis, was shown to oxidize under an oxidizing atmosphere before thermal reduction took place. With decreasing partial pressure of oxygen the initial oxidation was suppressed and only reduction of Co/Fe and loss of oxygen were observed under an inert atmosphere. The thermal expansion of BSCF under different atmospheres was determined from the thermal evolution of the cubic unit cell parameter, demonstrating that the thermal expansion of BSCF depends on the atmosphere. Chemical expansion of BSCF was also estimated based on the diffraction data and thermo-gravimetrical analysis. A hexagonal perovskite phase, coexisting with the cubic BSCF polymorph, was observed to be formed above 600 °C during heating. The phase separation leading to the formation of the hexagonal polymorph was driven by oxidation, and the unit cell of the cubic BSCF was shown to decrease with increasing amounts of the hexagonal phase. The hexagonal phase disappeared upon further heating, accompanied with an expansion of the unit cell of the cubic BSCFAuthor preprin

Adsorption-capacitive deionization hybrid system with activated carbon of modified potential of zero charge

This research article was published by Elsevier, 2023In this study water solutions are desalinated with carbon electrodes of modified surface charges. The idea is to endow the electrodes with the ability to physically adsorb salt ions without applying potential so as to save energy. The modification enhanced to decrease the energy consumption of a newly invented adsorption-CDI hybrid system by 19%, since modified activated carbon cell consumed 0.620 (relative error 3.00%) kWh/m3 compared to pristine activated carbon cell which consumed 0.746 (relative error 1.20%) kWh/m3. Further analysis revealed high adsorption capacity of the modified activated carbon electrode cell which exhibited 9.0 (relative error 2.22%) compared to activated carbon cell with 5.3 (relative error 5.66%) mg g−1. These results show the potential of surface modification in adding value to low cost activated carbons for application in CDI

Relaxed complex scheme and molecular dynamics simulation suggests small molecule inhibitor of human TMPRSS2 for combating COVID-19

This research article was published by Taylor & Francis online in 2021As the coronavirus disease 19 (COVID-19) pandemic continues to pose a health and economic crisis worldwide, the quest for drugs and/or vaccines against the virus continues. The human transmembrane protease serine 2 (TMPRSS2) has attracted attention as a target for drug discovery, as inhibition of its catalytic reaction would result in the inactivation of the proteolytic cleavage of the SARS-CoV-2 S protein. As a result, the inactivation prevents viral cell entry to the host’s cell. In this work, we screened and identified two potent molecules that interact and inhibit the catalytic reaction by using computational approaches. Two docking screening experiments were performed utilizing the crystal structure and holo ensemble structure obtained from molecular dynamics in bound form. There is enhancement and sensitivity of docking results to the holo ensemble as compared to the crystal structure. Compound 1 demonstrated a similar inhibition value to nafamostat by interacting with catalytic triad residues His296 and Ser441, thereby disrupting the already established hydrogen bond interaction. The stability of the ligand–TMPRSS2 complexes was studied by molecular dynamics simulation, and the binding energy was re-scored by using molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) binding free energy. The obtained compounds may serve as an initial point toward the discovery of potent TMPRSS2 inhibitors upon further in vivo validation

Extraction, phytochemistry, nutritional, and therapeutical potentials of rice bran oil: A review

Background: Rice is the third-most-produced crop in the world after corn and sugarcane, and due to its widespread production, its byproduct, rice bran, is widely available. One option to add value to this agricultural waste is by utilizing the potential phytochemicals in rice bran oil (RBO). Rice bran oil contains vital chemicals with medicinal and nutritional benefits. This paper examines the numerous ways that rice bran oil is extracted, the various phytochemicals that are present, as well as their potential for use in nutrition and medicine. Method: A review of literatures released from 1996 to 2023 was done, with just one more item of literature from 1973. The search was performed in various online platforms such as Google Scholar, PubMed, Science Direct, Springer, Research4Life, Web of Science, SciFinder, Science Open etc. The more recent literatures were given more consideration, and the older literatures were only taken into account when they were absolutely essential in light of the subject at hand. Results: Literature survey has revealed that the essential phytochemical components of RBO includes phenolic acids, flavonoids, γ-oryzanol and ferulic acids and vitamin E which constitutes tocopherols and tocotrienols as well as other unique fatty acids. Numerous therapeutical potentials, including antioxidant, anti-inflammatory, antidiabetic, and anticancer activities have been evidenced, thanks to these significant phytochemical ingredients. Additionally, numerous nutritional potentials of RBO have been researched and reported. Conclusions: This review consolidates information on the developments in RBO extraction techniques, phytochemical components, and their nutritional and medicinal benefits. Also included are the approach towards processing of rice bran. Considering the abundance and potential of this agrowaste, the use of RBO based phytochemicals for nutritional and therapeutic purpose is worthy pursuing further

Approaches to mitigation of hydrogen sulfide during anaerobic digestion process – A review

Anaerobic digestion (AD) is the primary technology for energy production from wet biomass under a limited oxygen supply. Various wastes rich in organic content have been renowned for enhancing the process of biogas production. However, several other intermediate unwanted products such as hydrogen sulfide, ammonia, carbon dioxide, siloxanes and halogens have been generated during the process, which tends to lower the quality and quantity of the harvested biogas. The removal of hydrogen sulfide from wastewater, a potential substrate for anaerobic digestion, using various technologies is covered in this study. It is recommended that microaeration would increase the higher removal efficiency of hydrogen sulfide based on a number of benefits for the specific method. The process is primarily accomplished by dosing smaller amounts of oxygen in the digester, which increases the system's oxidizing capacity by rendering the sulfate reducing bacteria responsible for converting sulfate ions to hydrogen sulfide inactive. This paper reviews physicochemical and biological methods that have been in place to eliminate the effects of hydrogen sulfide from wastewater treated anaerobically and future direction to remove hydrogen sulfide from biogas produced

Surface Diffusion of Oxygen Transport Membrane Materials Studied by Grain-Boundary Grooving

Mass transport mechanism responsible for grain-boundary grooving during thermal annealing of polished ceramics of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and La2NiO4+δ (LN) was revealed by atomic force microscopy. Surface diffusion mechanism was confirmed for both materials by the evolution of the grain-boundary width (w) with annealing time (t), and the surface diffusion coefficient was determined from the slope of w versus t1/4 following the theory by Mullins. An Arrhenius temperature dependence of the surface diffusion was observed, and the activation energy was determined to be 220 ± 30 and 450 ± 30 kJ/mol, respectively, for BSCF and LN. The surface diffusion data are discussed with respect to similar data for other oxide materials and cation and oxygen anion diffusion in BSCF and LN. Finally, the dihedral angle for both LN and BSCF was determined, and these are typical in the range reported for other oxide materials

Accommodating receptor flexibility and free energy calculation to reduce false positive binders in the discovery of natural products blockers of SARS-COV-2 spike RBD-ACE2 interface

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), which causes coronavirus disease-19 (COVID-19) has caused more than 2 million deaths around the globe. The high transmissibility rate of the disease is related to the strong interaction between the virus spike receptor-binding domain (RBD) and the human angiotensin-converting enzyme 2 (ACE2) as documented in several reports. In this study, using state-of-the-art computational methods, natural products were screened and their molecular mechanism to disrupt spike RBD-ACE2 recognition was evaluated. There is the sensitivity of results to receptor ensemble docking calculations. Binding free energy and MD simulation are important tools to evaluate the thermodynamics of binding stability and the capacity of top hits to disrupt RBD-ACE2 recognition. The free energy profiles provide a slight decrease in binding affinity of the virus-receptor interaction. Three flavonoids parvisoflavone B (3), alpinumisoflavone (5) and norisojamicin (2) were effective in blocking the viral entry by binding strongly at the spike RBD-ACE2 interface with the inhibition constant of 0.56, 0.78 and 0.93 μM, respectively. The same compounds demonstrated similar effect on free ACE2 protein. Compound (2), also demonstrated ability to bind strongly on free spike RBD. Well-tempered metadynamics established that parvisoflavone B (3) works by binding to three sites namely interface α, β and loop thereby inhibiting viral cell entry. Owing to their desirable pharmacokinetic properties, the presented top hit natural products are suggested for further SARS-COV-2 molecular targets and subsequent in vitro and in vivo evaluations

Ethnomedicinal uses, phytochemistry and pharmacological study of Ocimum americanum L.: A review

Background: Ocimum americanum L., commonly known as Hoary basil, is a wild aromatic shrub traditionally used to treat different ailments. Its leaves, flowers and aerial parts have been widely studied to evaluate its medicinal potential such as lowering blood pressure, treatment of microbial infections, malaria, cold, liver and eye problems. Purpose: This study aims to provide an in-depth review of ethnomedicinal uses, phytochemistry, and pharmacological activities of O. americanum, to evaluate its benefits, challenges and potential future prospects. Methods: All the information about O. americanum was collected from various platforms, including google scholar, PubMed, ScienceDirect, plants of the world online and Research4Life. The acceptance criteria of the collected information based on the PICOS model. The GRADE approach was used to analyze and evaluate the quality of the collected information. Results: This study showed that O. americanum has tremendous therapeutic potential to be integrated into mainstream medical practice to manage various medical conditions. The inconsistence of the phytoconstituents among the plant parts resulted in a significant variation of pharmacological activities. Plant originality, genetic variability and extraction techniques are among the factors contributing to the variation of phytoconstituents that are responsible for pharmacological activities. Conclusion: This study revealed that O. americanum is a potential medicinal plant for mitigating various medical conditions. However, future study should continue to focus on the bioactive compounds and their mechanisms of action. Additionally, the utilization of the O. americanum for the development of drugs as well as quality evaluation in clinical settings are highly recommended

Abrogating the nsp10–nsp16 switching mechanisms in SARS-CoV-2 by phytochemicals from Withania somnifera: a molecular dynamics study

This research article published by Taylor & Francis Online, 2021The search for therapeutic small molecules and vaccines for Covid-19 treatment is an urgent but evolving topic. The virus has claimed over 3,782,490 lives (as of 12 June 2021), with the figure expected to rise due to the high versatility of the SAR-CoV-2 variant. Therapeutic options based on SARS-CoV-2 inhibitor are essential. Withanolides have a long history in traditional medicines with versatile biological properties including antiviral activities. In this study, the inhibitory potential of withanolides from Withania somnifera (Ashwagandha) against SARS-CoV-2 non-structural protein 10 (nsp10) was investigated by employing atomistic in silico methods viz molecular docking, molecular dynamics and binding free energy calculations. Investigated Withania somnifera compounds demonstrated binding affinity to the nsp10 and in its complex form, that is, nsp10-nsp16 heterodimer. Two withanolides; withanoside IV and withanoside V isolated from the roots of Withania somnifera demonstrated strong inhibition with binding free energies of −29.5 and −29.1 kJ/mol, respectively. Molecular dynamics and binding free energy ascertained the stability of withanoside IV. Water molecules, although known to play an important role in mediating biological systems, herein, water was found to have a repulsive binding effect to some residues, suggesting that the binding of withanoside IV would require dewetting of the nsp10 or displacing the water to bulk solvents. Interestingly, residues in the nsp10 that are responsible for forming stable interaction at the nsp10–nsp16 were found to be strongly interacting with withanoside IV, hence weakening the nsp10–nsp16 interaction and recognition. Further in vitro and in vivo experiments are recommended to validate the anti-SARS-COV-2 potential of these phytochemicals