Synthesis, network structure and morphology of s-triazine-organosilane glassy hybrid materials

A series of five hybrid materials are synthesized by the reaction of cyanuric chloride (C₃N₃Cl₃) with different alkoxysilanes (R_xSi(OC₂H₅)_4−x, R=CH₃, C₆H₅ and x=0, 1, 2) in ethanol using sol–gel technique. The resulting s-triazine-organosilane products were examined using spectroscopic (UV–visible, FT-IR), thermal (thermogravimetric analysis, TGA), powder X-ray diffraction (P-XRD), BET analysis and microscopic (scanning electron microscopy, SEM) techniques. These hybrid materials exhibit globular and two-dimensional morphological textures with varying degrees of crystalline microstructures. Depending on the functionality of the organosilane building blocks the obtained hybrid materials exhibit different material characteristics including their solid state, Vicat softening point (Vicat hardness), density and porosity. BET surface area measurements indicate that these materials possess small specific surface areas of 0.36–2.3 m²/g with external surface area of ~0.02 m²/g. The phenyl-containing hybrids exhibit pronounced hydrolytic stability compared to the methyl- and silica-based analogs. The DMSO and sulfolane solutions of the prepared hybrids are transparent to visible light whereas their cold-compressed discs are optically opaque.     

Development and Greenness Assessment of HPLC Method for Studying the Pharmacokinetics of Co-Administered Metformin and Papaya Extract

Foods with medical value have been proven to be beneficial, and they are extensively employed since they integrate two essential elements: food and medication. Accordingly, diabetic patients can benefit from papaya because the fruit is low in sugar and high in antioxidants. An RP-HPLC method was designed for studying the pharmacokinetics of metformin (MET) when concurrently administered with papaya extract. A mobile phase of 0.5 mM of KH₂PO₄ solution and methanol (65:35, v/v), pH = 5 ± 0.2 using aqueous phosphoric acid and NaOH, and guaifenesin (GUF) were used as an internal standard. To perform non-compartmental pharmacokinetic analysis, the Pharmacokinetic program (PK Solver) was used. The method’s greenness was analyzed using two tools: the Analytical GREEnness calculator and the RGB additive color model. Taking papaya with MET improved the rate of absorption substantially (time for reaching maximum concentration (T_max) significantly decreased by 75% while maximum plasma concentration (C_max) increased by 7.33%). The extent of absorption reduced by 22.90%. Furthermore, the amount of medication distributed increased (30.83 L for MET concurrently used with papaya extract versus 24.25 L for MET used alone) and the clearance rate rose by roughly 13.50%. The results of the greenness assessment indicated that the method is environmentally friendly. Taking papaya with MET changed the pharmacokinetics of the drug dramatically. Hence, this combination will be particularly effective in maintaining quick blood glucose control.     

Design,Sonosynthesis, Quantum‐Chemical Calculations,and Evaluation of New Mono‐ and Bis‐pyridine Dicarbonitriles as Antiproliferative Agents

A highly efficient, simple, and clean single‐step sonosynthetic procedure has been sophisticated for assembling new series of mono‐ and bis‐pyridine dicarbonitriles from ketones, HCl, and tetracyanoethylene. The presented protocol is applicable for the preparation of a broad range of uniquely substituted pyridine dicarbonitriles and seems to be superior in comparison with other previously reported methods. The antiproliferative impact of the newly synthesized derivatives was screened towards three representative cancer cell lines (MCF‐7, A549, and HCT116). Most of the evaluated derivatives showed a moderate to excellent anti‐proliferative activity towards the selected cell lines. Of these, compounds 4h , 4k , 10 , 12a , and 12b showed both potent anticancer activity (IC₅₀<10 μM) and lower cytotoxic effect (IC₅₀ > 58 μM) on non‐tumorigenic cells (MCF‐10A and NCM460), suggesting their promising potential to be lead molecules for future antitumor drug discovery. The structure‐activity relationships have been also discussed. Moreover, quantum chemical studies based on Density Functional Theory (DFT) of the synthesized compounds were investigated and found to be consistent with the in vitro inhibitory activities.     

SAXS and DSC studies on the structural characteristics of siliconized s-triazine glassy hybrid materials

Three hybrid materials composed of planar s-triazine rings and polyhedral silica (SiO₂), phenylsilsesquioxane (PhSiO_1.5) and diphenylsiloxane (Ph₂SiO) building blocks were investigated by differential scanning calorimetry (DSC) and small angle X-ray scattering (SAXS) techniques. These measurements revealed that the geometrically dissimilar components were fully integrated into intact glassy hybrid structures. Their DSC thermograms showed that these hybrids are thermally stable below 350 °C with moderate glass transition temperatures (T_g) of 56–110 °C consistent with the increasing structural connectivity of the silicone component. The SAXS data was analyzed to obtain different structural information using Porod, Guinier and Kratky approximations. The general features of each of the SAXS profiles of these hybrids are very similar to those of polyphenylsilsesquioxane (PPhSQ). The SAXS profiles reveal that these hybrids can be described as nano-scale primary particles that are self-organized in macromolecular ensembles to form extended unfolded textures of varying scattering lengths (91–168 Å). The obtained hybrid particles adopt either 3-D bulk fractals with open structures or 2-D surface fractals with dense cores. The short interfacial thickness (< 3 Å) and the low thermal fluctuation parameters strongly suggest that these particles are held together by substantial cohesion forces.     

Spectrophotometric determination of some penicillins with ammonium vanadate

A spectrophotometric method for determining some penicillins has been developed. A known volume of the penicillin solution-in phosphate buffer of pH 6.8 is boiled with ammonium vanadate solution-in sulphuric acid medium-for 10 min and the absorbance of the colour formed is measured at 750 nm. The excess of vanadate can also be determined volumetrically. The method has been successfully applied for the determination of penicillin G sodium, phenoxymethyl penicillin, ampicillin sodium, phenethicillin potassium, cloxacillin sodium and methicillin sodium. The procedure is also used for analysing some pharmaceutical preparations of these drugs, e.g., injections. The results obtained are in agreement with those of the B P 1973 methods.     

Series Solutions of Time-Fractional Host-Parasitoid Systems

In this paper, Adomian’s decomposition method (ADM) has been used for solving time-fractional host-parasitoid system. The derivatives are understood in the Caputo sense. The reason of using fractional order differential equations (FOD) is that FOD are naturally related to systems with memory which exists in most biological systems. Also they are closely related to fractals which are abundant in biological systems. Numerical example justifies the proposed scheme.     

Mathematical model for the novel coronavirus (2019-nCOV) with clinical data using fractional operator

Coronavirus infection (COVID-19) is a considerably dangerous disease with a high demise rate around the world. There is no known vaccination or medicine until our time because the unknown aspects of the virus are more significant than our theoretical and experimental knowledge. One of the most effective strategies for comprehending and controlling the spread of this epidemic is to model it using a powerful mathematical model. However, mathematical modeling with a fractional operator can provide explanations for the disease's possibility and severity. Accordingly, basic information will be provided to identify the kind of measure and intrusion that will be required to control the disease's progress. In this study, we propose using a fractional-order SEIARPQ model with the Caputo sense to model the coronavirus (COVID-19) pandemic, which has never been done before in the literature. The stability analysis, existence, uniqueness theorems, and numerical solutions of such a model are displayed. All results were numerically simulated using MATLAB programming. The current study supports the applicability and influence of fractional operators on real-world problems.     

Determination of the range of alpha particles in SSNTD by optical density method

A technique based on the optical density (D) measurement of the etched track is useful for charged particles spectroscopy using SSNTD. It was shown that the stopping power of alpha particles in CR-39 is proportional to D. We measured the optical density and derived an expression to estimate the range of alpha particles in CR-39 detector as a function of the bulk etching rate and etching time. The relation between the etching time, track parameters (depth, radius) and D for different alpha particles energy and etching conditions were studied. A relation describing D as a function of track size is proposed.