Synthesis of 3,3′-methylenebis(4-hydroxyquinolin-2(1H)-ones) of prospective anti-COVID-19 drugs

Molecular Diversity - During formylation of 2-quinolones by DMF/Et3N mixture, the unexpected 3,3′-methylenebis(4-hydroxyquinolin-2(1H)-ones) were formed. The discussed mechanism was proved as...     

Coexistence and fluctuations phenomena with Davidson-like potentials in quadrupole-octupole deformed nuclei

The energy spectra of three types of two-dimensional potentials(we will call them‘Davidson-like potentials’(DLPs)),characterized by four minima separated by barriers,are investigated.The predictions for spectra and wave functions are obtained by using the nine-point finite-difference method.For these potentials,with the existence of a single configuration,a transition of spectra,as a function of barrier height,is covered from tunneling splitting modes to fluctuations phenomena,with equal peaks wave functions,crossing to the spectra of purely anharmonic oscillator potentials(AOPs).A different type of phase transition occurs when two(or more)configurations coexist.With the change of the parameters,a transition of spectra is covered from coexistence phenomena of two distinct quantum tunneling modes to fluctuations phenomena,with unequal peaks wave functions,crossing to the spectra of purely AOPs.Using DLPs,a particular application of the coherent quadropole-octupole model to describe energy bands with alternating parity of the nuclei¹⁰⁰Mo,^146,148Nd,^148,150Sm,²²⁰Ra,^220,222Rn,and^220,222Th is presented.The global parametrization of the model for the selected nuclei is achieved.     

Mesoporous polymer-coated PAN beads for environmental applications: fabrication,characterisation and uranium adsorption studies

Adsorption of U(VI) and other heavy metals on millimetre sized polymer-coated polyacrylinitrile (PAN) beads was investigated. PAN was used as scaffolds for the polymer layer thus producing porous material of high surface area, improved mechanical strength and improved adsorption capabilities. Extensive U(VI) adsorption studies were undertaken and results modelled using different kinetic and equilibrium models. Parameters including thermodynamic parameters were evaluated. Sorbent capacities were assessed as 124, 16, and 33 mg g^?1 for PCP, SPP and Dowex at 60 °C respectively. U(VI) adsorption mechanism for these adsorbents was postulated. Recovered uranium may be used for production of cheap electricity.     

Mixed convection boundary-layer flow over a vertical surface embedded in a porous medium

In this paper we have numerically investigated the existence and uniqueness of a vertically flowing fluid passed a model of a thin vertical fin in a saturated porous media. We have assumed the two-dimensional mixed convection from a fin, which is modelled as a fixed, semi-infinite vertical surface, embedded in a fluid-saturated porous media under the boundary-layer approximation. We have taken the temperature, in excess of the constant temperature in the ambient fluid on the fin, to vary as  , where is measured from the leading edge of the plate and λ is a fixed constant. The Rayleigh number is assumed to be large so that the boundary-layer approximation may be made and the fluid velocity at the edge of the boundary-layer is assumed to vary as . The problem then depends on two parameters, namely λ and , the ratio of the Rayleigh to Péclet numbers. It is found that when λ>0 (<0) there are (is) dual (unique) solution(s) when is grater than some negative values of (which depends on λ). When λ<0 there is a range of negative value of (which depends on λ) for which dual solutions exist and for both λ>0 and λ<0 there is a negative value of (which depends on λ) for which there is no solution. Finally, solutions for 0<1 and 1 have been obtained.     

Effect of temperature on the extraction of octahedral and tetrahedral cobalt(II) by 8-hydroxyquinoline and/or dibenzo-18-crown-6 or dibenzylamine

The extraction behavior of octahedral and tetrahedral cobalt(II) complexes from aqueous nitrate medium was studied in the system 8-hydroxyquinoline (HOX) and dibenzo-18-crown-6 (Db 18C6) or dibenzylamine (DBA) in chloroform at different temperatures to evaluate the thermodynamic functions as well as the equilibrium constants of each reaction. The stoichiometry of the extracted organic phase species were established to be Co(OX)₂·Db18C6 for the octahedral cobalt and Co(OX)₂·DBA for the tetrahedral cobalt.     

Positron annihilation lifetime and differential scanning calorimetric study of immiscible NBR/PE blends

The temperature dependence of the mean size of nanoscale free‐volume holes, 〈V_h〉, in polymer blend system consisting of polar and nonpolar polymers has been investigated. The positron lifetime spectra were measured for a series of polymer blends between polyethylene (PE) and nitrile butadiene rubber (NBR) as a function of temperature from 100 to 300 K. The glass transition temperatures (T_g) for blends were determined from the ortho‐positronium (o‐Ps) lifetime τ₃ and the mean size of free‐volume holes 〈V_h〉 versus temperature as a function of wt % of NBR. The T_gs estimated from the PALS data agree very well with those estimated from DSC in view of different time scales involved in the two measurements. Both DSC and PALS results for the blends showed two clear T_gs of a two‐phase system. Furthermore, from the variation of thermal expansivity of the nanoscale free‐volume holes, the thermal expansion coefficients of glass and amorphous phases were estimated. Variations of the o‐Ps formation probability I₃ versus temperature for pure PE and blends with low wt % of NBR were interpreted on the basis of the spur reaction model of Ps formation with reference to the effects of localized electrons and trapping centers produced by positron irradiation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 227–238, 2009     

A theoretical approach to determination of the thermal diffusivity of solids by using a periodic heating technique

The present work is part of a program aimed at development of an experiment to determine the thermal diffusivity of solids by using the method of periodic heating. The spacetime heat conduction equation is solved analytically in the form of an infinite series for a slab with a uniform initial temperature. One of the slab surfaces is maintained at a constant temperature, while the other is subjected to a periodic temperature. We have proved numerically that the series can be truncated to a few terms according to the slab thickness, giving a negligible error. On the basis of the discussed theoretical approach, the experimental requirements are suggested for determination of the thermal diffusivity of solids.

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Zusammenfassung Vorliegende Arbeit ist Teil eines Experimenteprogrammes zur Bestimmung der TemperaturleitfÄhigkeit von Feststoffen mittels der Methode des periodischen Erhitzens. Die Raumzeit-Gleichung für die WÄrmeleitfÄhigkeit wurde für eine Platte mit homogener Ausgangstemperatur analytisch in Form einer unendlichen Reihe gelöst. Eine der PlattenoberflÄchen wird auf konstanter Temperatur gehalten, wÄhrend die andere einer periodischen Temperatur ausgesetzt wird. Es konnte gezeigt werden, da\ die Reihen je nach Dicke der Platte nach einigen Gliedern abgebrochen werden können, ohne dabei einen unvernachlÄssigbaren Fehler zu begehen. Auf der Grundlage der theoretischen Ergebnisse wurden experimentelle Anforderungen zur Bestimmung der TemperaturleitfÄhigkeit von Feststoffen erarbeitet.

     

1,4‐Dioxo‐1,4‐dihydronaphthalene‐2,3‐dicarbonitrile and 1,1,2,2‐Tetracyanoethene in Heterocyclization

This survey is mainly concerned with selected reactions of 1,4‐dioxo‐1,4‐dihydronaphthalene‐2,3‐dicarbonitrile and 1,1,2,2‐tetracyanoethene, which have use or potential use in heterocyclic synthesis.     

Novel pyrrolidinone and pyrazolo[1,5-a][1,3,5]triazine derivatives bearing a biologically active sulfamoyl moiety as a new class of antitumor agents

Abstract  

Sulfonamides possess many types of biological activities and have recently been reported to show substantial antitumor activity in vitro and/or in vivo. There are a variety of mechanisms for the anticancer activity. The present work reports the synthesis of some novel pyrrole, oxopyrrole, and related pyrroloacetamide derivatives, hydrazones, aminopyrazolinone, thiocarbamoyl, and pyrazolo[1,5-a][1,3,5]triazine derivatives bearing a substituted sulfonamide moiety. All newly synthesized compounds were evaluated for their in vitro anticancer activity against the breast cancer cell line MCF7. Most of the screened compounds showed interesting cytotoxic activities compared with doxorubicin as a reference drug.     

Chromatographic separation of neodymium isotopes by using chemical exchange process

The neodymium isotope effects were investigated in Nd–malate ligand exchange system using the highly porous cation exchange resin SQS-6. The temperature of the chromatographic columns was kept constant at 50 °C by temperature controlled water passed through the columns jackets. The separation coefficient of neodymium isotopes, ?’s, was calculated from the isotopic ratios precisely measured by means of an ICP mass spectrometer equipped with nine collectors as ion detectors. The separation coefficient, ? × 10⁵, were calculated and found to be 1.4, 4.8, 5.4, 10.6, 16.8 and 20.2 for ¹⁴³Nd, ¹⁴⁴Nd, ¹⁴⁵Nd, ¹⁴⁶Nd, ¹⁴⁸Nd and ¹⁵⁰Nd, respectively.