Holospiniferoside: A New Antitumor Cerebroside from The Red Sea Cucumber Holothuria spinifera: In Vitro and In Silico Studies

Chemical investigation of the methanolic extract of the Red Sea cucumber Holothuria spinifera led to the isolation of a new cerebroside, holospiniferoside (1), together with thymidine (2), methyl-α-d-glucopyranoside (3), a new triacylglycerol (4), and cholesterol (5). Their chemical structures were established by NMR and mass spectrometric analysis, including gas chromatography–mass spectrometry (GC–MS) and high-resolution mass spectrometry (HRMS). All the isolated compounds are reported in this species for the first time. Moreover, compound 1 exhibited promising in vitro antiproliferative effect on the human breast cancer cell line (MCF-7) with IC₅₀ of 20.6 µM compared to the IC₅₀ of 15.3 µM for the drug cisplatin. To predict the possible mechanism underlying the cytotoxicity of compound 1, a docking study was performed to elucidate its binding interactions with the active site of the protein Mdm2–p53. Compound 1 displayed an apoptotic activity via strong interaction with the active site of the target protein. This study highlights the importance of marine natural products in the design of new anticancer agents.     

Eu3+离子对Li2O-Na2O-B2O3物理和光学特性的影响

The lithium sodium borate glasses doped with Eu³⁺ ion are prepared using melt quenching technique, their structural and optical properties have been evaluated. The density of prepared glasses exhibits an inverse behavior to the molar volume ranging from 2.26 g/cm³ to 2.43 g/cm³ and 26.95 cm³ /mol to 26.20 cm³ /mol, respectively. The absence of sharp peaks in XRD patterns confirms the amorphous nature of the prepared glasses. The absorption spectra yield four transitions centered at 391 nm (⁷F₀→⁵L₆), 463 nm (⁷F₀→⁵D₂), 531 nm (⁷F₀→⁵D₁), and 582 nm (⁷F₀→⁵D₀). The most intense red luminescence is observed at 612 nm corresponding to ⁵D₀→⁷F₂ transition under 390 nm laser excitations.     

Statistical relationship between activity concentrations of radionuclides 226Ra, 232Th, 40K,and 137Cs and geological formations in surface soil of Jordan

An extensive study was conducted to determine the activity concentrations of natural and artificial radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs in soil samples of each governate of Jordan. A total of 370 samples have been measured using a high-purity germanium detector. The activity concentration for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs has mean values of 42?±?3, 23?±?3, 309?±?21, and 3.7?±?0.9 Bq kg^–1, respectively. The highest mean activity concentration for ²²⁶Ra was found to be 138?±?4 Bq kg^–1 in the Alkarak governate. In the Ajloun and Jarash governates, the highest mean activity concentration was 35?±?3 Bq kg^–1 for ²³²Th, and 14.2?±?1.9 Bq kg^–1 for ¹³⁷Cs, respectively. Geological influence on the activity concentrations was investigated using the one-way analysis of variance (ANOVA) and independent samples. The ANOVA results indicate that there are strong significant differences between the activity concentrations of ²³²Th, ⁴⁰K, and ¹³⁷Cs based on geological formations the radionuclides occur. The main contribution to gamma dose rate was due to ²²⁶Ra activity concentration. Radium equivalent and external hazard index are associated with a mean value of 98 Bq kg^–1, and 0.266, respectively.     

Fluorescence Quantum Yield Determination of Propylparaben Using Flow Injection Spectroscopy

The determination of the fluorescence quantum yield of Propylparaben is introduced and applied to L-tyrosine as a standard by a new approach that can be applied to the pharmaceutical compound utilised in this study. The quantum yield is a critical figure of quality for the optical nature of a fluorophore. Numerous investigations have considered the glitter in both pharmaceutical and nature compounds for its medical and industrial significance. A straightforward method is detailed here to decide the quantum yield of Propylparaben in solution as an element of the fluorescence concentration. For this reason, L-Tyrosine is chosen as a fluorescence standard perspective to gauge the Propylparaben fluorescence quantum yield. The impacts of pH, solvents and flow rate on the assessment of quantum yield and quantum efficiency, for the reference and the solutions of Propylparaben, have been investigated. The results indicated that these parameters significantly influence the accuracy of the method. Diverse methods are concentrated on to represent distinctive quantum yield advancements with the quantum efficiency. The impact of these parameters was likewise considered. In this study, the application of the single method may be taken into consideration to compute quantum yield of Propylparaben, which was 0.36, and this is an exceptionally basic and general technique to solve the imperative issue of luminescence quantum yield assurance of other fluorescence compounds.     

5‐Phenyl‐1,3,4‐oxadiazole‐2‐thiol/polyamide‐montmorillonite microbicides nanocomposites as drug delivery system

The preparation and structural characterization of polymeric microbicides consisting of 5‐phenyl‐1,3,4‐oxadiazole‐2‐thiol covalently bound to polyamide based on diethyl‐2,3‐dihydroxysuccinate and polyoxypropylenetriamine Jeffamine (T₄₀₃) are described. Two different mole ratios of 5‐phenyl‐1,3,4‐oxadiazole‐2‐thiol was reacted with chloroacetylated diethyl‐2,3‐dihydroxysuccinate followed by polycondensation with Jeffamine (T₄₀₃). The nanocomposites were prepared by modification of microbicide polyamides to yield polymers with phosphonium salt or amine hydrochloride salt followed by ion exchange process between the phosphonium salt or amine hydrochloride of the polyamides and the intermellar sodium cation of the clay mineral montmorillonite. The monomers were characterized by mass spectrum, proton nuclear magnetic resonance. The polymers showed good or moderate antimicrobial activities. Nanocomposites were characterized by Fourier transformed infrared spectroscopy, X‐ray diffraction, thermal gravimetric analysis, and transmission electron microscope. The swelling behavior and release of 5‐phenyl‐1,3,4‐oxadiazole‐2‐thiol in different pH values (2.3, 5.8, and 7.4) were studied. A slow release, ranging from 12% to 28% after 50 hours was recorded from nanocomposites. However, the release profile reached almost 70% from polyamides. The antimicrobial activity of the polyamides was studied against gram‐negative bacteria, gram‐positive bacteria, yeast, and the filamentous fungi by well diffusion method. The polyamides showed better antimicrobial activities than 5‐phenyl‐1,3,4‐oxadiazole‐2‐thiol.     

Axisymmetric flow and heat transfer of the Carreau fluid due to a radially stretching sheet: Numerical study

The prime objective of this article is to study the axisymmetric flow and heat transfer of the Carreau fluid over a radially stretching sheet. The Carreau constitutive model is used to discuss the characteristics of both shear-thinning and shear-thickening fluids. The momentum equations for the two-dimensional flow field are first modeled for the Carreau fluid with the aid of the boundary layer approximations. The essential equations of the problem are reduced to a set of nonlinear ordinary differential equations by using local similarity transformations. Numerical solutions of the governing differential equations are obtained for the velocity and temperature fields by using the fifth-order Runge–Kutta method along with the shooting technique. These solutions are obtained for various values of physical parameters. The results indicate substantial reduction of the flow velocity as well as the thermal boundary layer thickness for the shear-thinning fluid with an increase in the Weissenberg number, and the opposite behavior is noted for the shear-thickening fluid. Numerical results are validated by comparisons with already published results.     

Effect of Time Periodic Boundary Conditions on Convective Flows in a Porous Square Enclosure with Non-Uniform Internal Heating

The problem of unsteady natural convection in a square region filled with a fluid-saturated porous medium having non-uniform internal heating and heated laterally is considered. The heated wall surface temperature varies sinusoidally with the time about fixed mean temperature. The opposite cold wall is maintained at a constant temperature. The top and bottom horizontal walls are kept adiabatic. The flow field is modelled with the Darcy model and is solved numerically using a finite difference method. The transient solutions obtained are all periodic in time. The effect of Rayleigh number, internal heating parameters, heating amplitude and oscillating frequency on the flow and temperature field as well as the total heat generated within the convective region are presented. It was found that strong internal heating can generate significant maximum fluid temperatures above the heated wall. The location of the maximum fluid temperature moves with time according to the periodically changing heated wall temperature. The augmentation of the space-averaged temperature in the cavity strongly depends on the heating amplitude and rather insensitive to the oscillating frequency.     

Bis(ferrocenium) bis[tetrachloroantimonate(III)] trichloroantimony(III)

In the title compound, [Fe(C₅H₅)₂]₂[SbCl₄]₂[SbCl₃], the cyclo­penta­dienyl rings in both cations are parallel, with a nearly eclipsed conformation. The Sb³⁺ ions are coordinated by six Cl^? ions to form octahedral arrangements, of which two are slightly distorted. These octahedra form infinite chains along the c axis through Cl—Sb—Cl bridges.     

Transient Crystal Size Distribution in DTB and FC Crystallizers

This work deals with the transient analysis of crystal size distribution (CSD) for imperfectly mixed draft tube baffled (DTB) and forced circulation (FC) crystallizers. The DTB and FC crystallizers are described by the Compartmental and Mixed models respectively. Monte Carlo (MC) scheme has been employed for simulation purposes. The simulation results have been compared with the available experimental data of BENNETT and VAN BUREN for continuous urea crystallizers.     

Energy and Entropy Production of Nanofluid within an Annulus Partly Saturated by a Porous Region

The flow and heat transfer fields from a nanofluid within a horizontal annulus partly saturated with a porous region are examined by the Galerkin weighted residual finite element technique scheme. The inner and the outer circular boundaries have hot and cold temperatures, respectively. Impacts of the wide ranges of the Darcy number, porosity, dimensionless length of the porous layer, and nanoparticle volume fractions on the streamlines, isotherms, and isentropic distributions are investigated. The primary outcomes revealed that the stream function value is powered by increasing the Darcy parameter and porosity and reduced by growing the porous region’s area. The Bejan number and the average temperature are reduced by the increase in Da, porosity ε, and nanoparticles volume fractions ϕ. The heat transfer through the nanofluid-porous layer was determined to be the best toward high rates of Darcy number, porosity, and volume fraction of nanofluid. Further, the local velocity and local temperature in the interface surface between nanofluid-porous layers obtain high values at the smallest area from the porous region (D=0.4), and in contrast, the local heat transfer takes the lower value.