Synthesis and greener pastures biological study of bis-thiadiazoles as potential Covid-19 drug candidates.

A novel series of bis- (Abdelhamid et al., 2017, Banerjee et al., 2018, Bharanidharan et al., 2022)thiadiazoles was synthesized from the reaction of precursor dimethyl 2,2'-(1,2-diphenylethane-1,2-diylidene)-bis(hydrazine-1-carbodithioate) and hydrazonyl chlorides in ethanol under ultrasonic irradiation. Spectral tools (IR. NMR, MS, elemental analyses, molecular dynamic simulation, DFT and LUMO and HOMO) were used to elucidate the structure of the isolated products. Molecular docking for the precursor, 3 and ligands 6a-i to two COVID-19 important proteins Mpro and RdRp was compared with two approved drugs, Remdesivir and Ivermectin. The binding affinity varied between the ligands and the drugs. The highest recorded binding affinity of 6c with Mpro was (-9.2 kcal/mol), followed by 6b and 6a, (-8.9 and -8.5 kcal/mol), respectively. The lowest recorded binding affinity was (-7.0 kcal/mol) for 6 g. In comparison, the approved drugs showed binding affinity (-7.4 and -7.7 kcal/mol), for Remdesivir and Ivermectin, respectively, which are within the range of the binding affinity of our ligands. The binding affinity of the approved drug Ivermectin against RdRp recoded the highest (-8.6 kcal/mol), followed by 6a, 6 h, and 6i are the same have (-8.2 kcal/mol). The lowest reading was found for compound 3 ligand (-6.3 kcal/mol). On the other side, the amino acids also differed between the compounds studied in this project for both the viral proteins. The ligand 6a forms three H-bonds with Thr 319(A), Sr 255(A) and Arg 457(A), whereas Ivermectin forms three H-bonds with His 41(A), Gly143(A) and Gln 18(A) for viral Mpro. The RdRp amino acids residues could be divided into four groups based on the amino acids that interact with hydrogen or hydrophobic interactions. The first group contained 6d, 6b, 6 g, and Remdesivir with 1-4 hydrogen bonds and hydrophobic interactions 1 to 10. Group 2 is 6a and 6f exhibited 1 and 3 hydrogen bonds and 15 and 14 hydrophobic interactions. Group 3 has 6e and Ivermectin shows 4 and 3 hydrogen bonds, respectively and 11 hydrophobic interactions for both compounds. The last group contains ligands 3, 6c, 6 h, and 6i gave 1-3 hydrogen bonds and 6c and 3 recorded the highest number of hydrophobic interactions, 14 for both 6c and 6 h. Pro Tox-II estimated compounds' activities as Hepatoxic, Carcinogenic and Mutagenic, revealing that 6f-h were inactive in all five similar to that found with Remdesivir and Ivermectin. The drug-likeness prediction was carried out by studying physicochemical properties, lipophilicity, size, polarity, insolubility, unsaturation, and flexibility. Generally, some properties of the ligands were comparable to that of the standards used in this study, Remdesivir and Ivermectin.

Recent progress in the applications of silica-based nanoparticles.

Functionalized silica nanoparticles (SiO2 NPs) have attracted great attention due to their promising distinctive, versatile, and privileged physiochemical characteristics. These enhanced properties make this type of functionalized nanoparticles particularly appropriate for different applications. A lack of reviews that summarizes the fabrications of such nanomaterials and their different applications in the same work has been observed in the literature. Therefore, in this work, we will discuss the recent signs of progress in the fabrication of functionalized silica nanoparticles and their attractive applications that have been extensively highlighted (advanced catalysis, drug-delivery, biomedical applications, environmental remediation applications, and wastewater treatment). These applications have been selected for demonstrating the role of the surface modification step on the various properties of the silica surface. In addition, the current challenges in the applications of functionalized silica nanoparticles and corresponding strategies to discuss these issues and future perspectives for additional improvement have been addressed.

Design, synthesis, and biological evaluation of novel pyrido-dipyrimidines as dual topoisomerase II/FLT3 inhibitors in leukemia cells.

Dual inhibition of topoisomerase (topo) II and FLT3 kinase, as in the case of C-1311, was shown to overcome the shortcomings of using topo II inhibitors solely. In the present study, we designed and synthesized two series of pyrido-dipyrimidine- and pseudo-pyrido-acridone-containing compounds. The two series were evaluated against topo II and FLT3 as well as the HL-60 promyelocytic leukemia cell line in vitro. Compounds 6, 7, and 20 showed higher potency against topo II than the standard amsacrine (AMSA), whereas compounds 19 and 20 were stronger FLT3 inhibitors than the standard DACA. Compounds 19 and 20 showed to be dual inhibitors of both enzymes. Compounds 6, 7, 19, and 20 were more potent inhibitors of the HL-60 cell line than the standard AMSA. The results of the in vitro DNA flow cytometry analysis assay and Annexin V-FITC apoptosis analysis showed that 19 and 20 induced cell cycle arrest at the G2/M phase, significantly higher total percentage of apoptosis, and late-stage apoptosis in HL-60 cell lines than AMSA. Furthermore, 19 and 20 upregulated several apoptosis biomarkers such as p53, TNFα, caspase 3/7 and increased the Bax/Bcl-2 ratio. These results showed that 19 and 20 deserve further evaluation of their antiproliferative activities, particularly in leukemia. Molecular docking studies were performed for selected compounds against topo II and FLT3 enzymes to investigate their binding patterns. Compound 19 exerted dual fitting inside the active site of both enzymes.

A novel method for highly effective removal and determination of binary cationic dyes in aqueous media using a cotton-graphene oxide composite.

The presence of dyes in industrial wastewater is a serious problem that hazards the surrounding environment. Therefore, this work investigates the removal of a binary dye system composed of Methylene Blue (MB) and Crystal Violet (CV) using an innovative composite (cotton fiber-graphene oxide (C-GO)). The simultaneous determination of the concentrations of the dyes in the binary system is a challenge. Thus, a new method was investigated to simultaneously detect the concentration of the dyes in the binary system using first-order derivative UV spectra to avoid the complex overlap of the maximum peaks in the original zero-order absorption spectra. Different parameters affecting the filter sorption mode, such as the concentration of the dyes, the dose of the (C-GO) composite, the dose of NaCl, flow rate, temperature, and pH, were investigated. The data obtained showed high adsorption efficiency for the binary dye system (>99%). This was approved based on the maximum sorption capacity (Q°) value obtained for the Langmuir model. Furthermore, this technique was developed, evaluated and applied to treat real industrial waste. The obtained data showed that the C-GO composite was highly efficient in treating industrial wastewater containing such dyes when a sufficient quantity is used. Therefore, it can be used as a promising adsorbent for such dyes in wastewater treatment processes.

Decontamination of organic pollutants from aqueous media using cotton fiber-graphene oxide composite, utilizing batch and filter adsorption techniques: a comparative study.

Cotton fiber-graphene oxide (C-GO) composite with high adsorptive properties towards the cationic dye, crystal violet (CV), was successfully fabricated by simple mixing of cotton fiber and GO in aqueous solution using a homogenizer. The as-prepared composite was characterized using TEM, SEM, LOM, XRD, FTIR, Raman and TGA. The characterization indicated that the formation of a homogeneous composite occurred via adequate mixing of the cotton fiber and GO. The fine structure of the obtained composite was successfully used in two adsorption techniques, namely batch adsorption and filter adsorption. Various parameters affecting batch adsorption, such as contact time, dye concentration, composite dose, NaCl dose, temperature and pH were investigated. In the filter adsorption mode, dye concentration, composite dose, NaCl dose, temperature, flow rate and pH were studied. A comparison study between the two techniques, i.e., batch adsorption and filter adsorption, are reported. The filter adsorption technique shows higher adsorption efficiency than the batch one, which was evident from the maximum adsorption capacity (Q°) values, obtained from the Langmuir isotherm. Further, the filter technique was developed and evaluated. This was achieved by regeneration, scaling-up and, finally, using another model of cationic dye (methylene blue).

Investigation of some factors affecting on release of radon-222 from phosphogypsum waste associated with phosphate ore processing.

The aim of this study is oriented to investigate the influence of some physicochemical factors such as radium distribution, grain size, moisture content and chemical constituents on releases of radon-222 from the accumulated phosphogypsum (PG) waste. The emanation fraction, activity concentration in the pore and the surface exhalation rate of radon-222 in the bulk PG waste are 34.5 ± 0.3%, 238.6 ± 7.8 kBq m(-3) and 213 ± 6.9 mBq m(-2) s(-1), respectively. These values were varied and enhanced slightly in the fine grain sizes (F1 < 0.125 mm) by a factor of 1.05 folds compared to the bulk residue. It was also found that release of radon from residue PG waste was controlled positively by radium (Ra-226), calcium (CaSO4) and strontium (SrO). About 67% of radon release attributed to the grain size below 0.5 mm, while 33% due to the large grain size above 0.5 mm. The emanation fraction of Rn-222 is increased with moisture content and the maximum emanation is ∼43% of moisture of 3-8%. It reduced slowly with the continuous increase in moisture till 20%. Due to PG waste in situ can be enhancing the background to the surround workers and/or public. Therefore, the environmental negative impacts due to release of Rn-222 can be minimized by legislation to restrict its civil uses, or increasing its moisture to ∼10%, or by the particle size separation of the fine fraction containing the high levels of Ra-226 followed by a suitable chemical treatment or disposal; whereas the low release amount can be diluted and used in cement industry, roads or dam construction.

Extraction and separation of Co(II) and Ni(II) from acidic sulfate solutions using Aliquat 336.

Extraction and separation of Co(II) and Ni(II) from acidic sulfate solutions by solvent extraction technique were studied using different forms of Aliquat 336 diluted with kerosene. The extraction percent of each metal ion was found to increase with increasing pH and extractant concentration. Co(II) was preferentially extracted by different forms of Aliquat 336 over Ni(II) under the same extraction conditions. From analysis of the experimental results, the extraction mechanism of R(4)N-forms was proposed with Co(II). It was found that the highest separation factor (S(Co/Ni)) value of 606.7 was obtained with 0.36 M R(4)N-SCN in kerosene from 2.0M H(2)SO(4) solution at pH 4.8 and shaking time of 20 min. Stripping of the two metal ions from the organic phase was also investigated. Based on the experimental results, a separation method was developed and tested to separate high purity Co(II), Ni(II) and Ln(III) from Ni-MH batteries leached by 2.0M H(2)SO(4). Based on the experimental results, a flow sheet was developed and tested and 0.34 g Co, 1.39 g Ln and 5.2g Ni were obtained from the leaching process.

Kinetics of acid leaching of ilmenite decomposed by KOH Part 2. Leaching by H2SO4 and C2H2O4.

A kinetic study of the leaching of ilmenite paste (resulting from ilmenite treatment by KOH) by sulfuric and oxalic acids has been investigated. The effects of the reaction agitation speed, ilmenite paste particle size, acid concentration, acid/paste mass ratio and temperature on titanium recovery percent from the KOH decomposed ilmenite are reported. The leaching rates are significantly influenced by the reaction temperature and acid concentration. The observed effects of the relevant operating variables on the leaching rates are consistent with a kinetic model for chemical control. The apparent activation energy for the leaching of titanium has been calculated using the Arrhenius expression. The data obtained are compared and discussed with available reported results. Further a flow diagram for production of TiO(2) based on KOH decomposition of ilmenite paste-oxalic acid leaching is given.