A fascinating aspect of the Diels–Alder reaction is its endo selectivity. This endo preference is much less pronounced in intermolecular cases compared with the intramolecular and transannular Diels–Alder (IMDA and TADA) reactions. Nevertheless, high endo selectivity is observed in the Diels– Alder additions of (E)-1-O-substituted dienes catalyzed by Lewis acids that lead to cis-1,6-disubstitut...

objective(s) in recent years highly selective cox-2inhibitors were withdrawn from the market because of an increased risk of cardiovascular complications. in this study we were looking for potent compounds with moderate selectivity for cox-2. so, four analogues of 4, 5-diaryl-2-(2-alkylthio-5-imidazolyl) imidazole derivatives were synthesized and their anti-inflammatory and anti-nociceptive act...

the objective of this study was to determine the relationship between body weight (bw) and heart girth (hg) in sardi and timahdite sheep in order to develop a prediction equation of bw from hg. the data used for this study included 476 records on bw and hg (227 in sardi and 249 in timahdite) collected on males and females of different ages in 33 private farms. the bw and the hg averaged 34.8 ± ...

In this work, the effects of operative parameters on CH4, CO2, O2, and N2 membrane gas separation for poly (4-methyl-1-pentane) (PMP) membrane modified by adding nanoparticles of TiO2, ZnO, and Al2O3 are assessed and investigated. The operative parameters were type and percentage of nanoparticles, and cross membrane pr...

A pH electrode for the selective determination of H+ was introduced. Both phosphorated calix[6]arene and a N,N'-bisethoxycarbonyl-1,10-diaza-4,7,13,16-tetraoxacyclo-octadecane (DZCE) were used as new H+-ionophores. The calibration graphs of the obtained electrodes exhibits satisfactory Nernstian slopes. The electrodes were compared to blank membranes (without any ionophoric substances) for the ...

On the basis of granular synthetic zeolites NaY, HY, and ZSM-5, adsorbents containing nanoparticles silver, cobalt, molybdenum, tungsten were obtained. The samples have a lower surface polarity in comparison with initial zeolites, which is reflected selectivity number respect to argon. This due fact that argon molecule interacts only through nonspecific forces. Modification was performed by int...

reference evapotranspiration is an important parameter in irrigation systems' design that is evaluated through either direct (lysimeter) or calculated method (empirical equations). when there is a lack of lysimeters' data, penman monteith fao method could be employed as a standard method for evaluating the other empirical methods' results. in this research, 13 year evaporation pa...

Calcium-selective ion channels are known to have carboxylate-rich selectivity filters, a common motif that is primarily responsible for their high Ca(2+) affinity. Different Ca(2+) affinities ranging from micromolar (the L-type Ca channel) to millimolar (the ryanodine receptor channel) are closely related to the different physiological functions of these channels. To understand the physical mec...

The present study describes the use of a new carbon paste electrode modified by means of Silica nanoparticles prepared by a simple and rapid procedure for the determination of sodium diclofenac (DCF). Moreover, the present study focuses on the characterization of electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) of the prepared Silica NPs-CPE. In this work, The...