Porous metal-organic truncated octahedron constructed from paddle-wheel squares and terthiophene links

A metal-organic truncated octahedron (termed MOP-28) has been constructed from six rigid square-shaped Cu2(CO2)4 paddle-wheel building units and twelve 2,2':5',2' '-terthiophene-5,5' '-dicarboxylate (TTDC) linkers. TTDC linker in the cis,cis conformation provides the critical 90 degrees linkage for this unique construction. The porous structure of MOP-28 is maintained even after the removal of guest species, as evidenced by this compound's nitrogen sorption isotherm of Type I characteristics and unprecedented surface area (Langmuir surface area 1100 m2/g, BET surface area 914 m2/g) among materials composed of discrete molecules.     

A G2(MP2) theoretical study of substituent effects on H3BNHnCl3−n (n= 3-0) donor-acceptor complexes

The complexation energies of H₃BNH_nCl_3−n (n= 3-0) complexes and the proton affinities of NH_nCl_3−n compounds have been computed at the G2(MP2) level of theory. G2(MP2) results show that the successive chlorine substitution on the ammonia decreases both the basicity of the NH_nCl_3−n ligands and the stability of H₃BNH_nCl_3−n complexes. The findings are interpreted in terms of the rehybridisation of the nitrogen lone-pair orbital. The NBO partitioning scheme shows that the variation of the N-H and N-Cl bond lengths, upon complexation, is due to variation of “s” character in these bonds.      

Variation de la L-norme de la 1-forme de torsion sur une variété hermitienne compacte

Let (M,g) be a complex compact hermitian manifold with dimension complex dim_C = m ≥ 2, we study in this paper the critical points of the functional: in the set of the hermitian metrics with total volume equal to one, where θ is 1 — form of torsion of the Chern connexion and r is a real number such that 1 ≤ r ≤ m. We show that the critical points of this functional are exactly a semi-kählerian metric.     

Hygrometric Determination of Water Activities and Osmotic and Activity Coefficients of NH4Cl–KCl–H2O at 25°C

Relative humidities have been measured for mixed aqueous electrolyte system of ammonium and potassium chlorides by the hygrometric method at total molalities from 0.3 to 6 mol-kg^–1for ionic-strength fractions yof NH₄Cl of 1/3, 1/2, and 2/3 at 25°C. The data allow the calculation of new water activities and osmotic coefficients. The proposed ECA (extended composed additivity) rule of calculation of water activity in mixed aqueous electrolyte solutions from the water activities of a single component is extended to this system. The experimental results and the predictions of the ECA rule are compared with the Robinson–Stokes, Reilly–Wood–Robinson, the Pitzer, and the Lietzke–Stoughton II models. Predictions made using these models are, in general, consistent with our results. From these measurements, the Pitzer mixing ionic parameters are determined and used to predict the solute activity coefficients in the mixture for different ionic-strength fractions.     

Hygrometric Determination of the Water Activities of the Aqueous Solutions of the Mixed Electrolyte NaCl–CaCl2–H2O at 25°C

The mixture {yNaCl + (1 – y)CaCl₂}(aq) has been studied with the hygrometric method at the temperature 25°C. The water activities were measured at total molalities from 0.25 mol-kg^–1 to near saturation for different ionic-strength fractions y of NaCl with y = 0.33, 0.50, and 0.67. The obtained data allow the calculation of osmotic coefficients. The experimental results are compared with the predictions of the Zdanovskii–Stokes–Robinson (ZSR), Kusik and Meissner (KM), Robinson and Stokes (RS), Lietzke and Stoughton (LS II), Reilly–Wood–Robinson (RWR), and Pitzer models. From the measured osmotic coefficients, the Pitzer ionic mixing parameters _{Na Ca} and _{Na Ca} Cl are determined and are used to predict the solute activity coefficients in the mixtures. The excess Gibbs energy is also determined. These results are compared with those given in the literature.     

Subdifferentials of the Marginal Functions in Parametric Convex Optimization via Intersection Formulas

Journal of Optimization Theory and Applications - The aim of the present work is to use a metric intersection formula to estimate the subdifferential of the marginal function in the convex setting....     

Numerical spectral examination of EMHD mixed convective flow of second-grade nanofluid towards a vertical Riga plate using an advanced version of the revised Buongiorno’s nanofluid model

Journal of Thermal Analysis and Calorimetry - Present communication aims to determine the impact of Cattaneo–Christov model and convective boundary on second-grade nanofluid flow alongside a...     

Continuous Data Assimilation Using General Interpolant Observables

We present a new continuous data assimilation algorithm based on ideas that have been developed for designing finite-dimensional feedback controls for dissipative dynamical systems, in particular, in the context of the incompressible two-dimensional Navier–Stokes equations. These ideas are motivated by the fact that dissipative dynamical systems possess finite numbers of determining parameters (degrees of freedom) such as modes, nodes and local spatial averages which govern their long-term behavior. Therefore, our algorithm allows the use of any type of measurement data for which a general type of approximation interpolation operator exists. Under the assumption that the observational measurements are free of noise, our main result provides conditions, on the finite-dimensional spatial resolution of the collected data, sufficient to guarantee that the approximating solution, obtained by our algorithm from the measurement data, converges to the unknown reference solution over time. Our algorithm is also applicable in the context of signal synchronization in which one can recover, asymptotically in time, the solution (signal) of the underlying dissipative system that is corresponding to a continuously transmitted partial data.     

Effect of Hibiscus sabdariffa and its anthocyanins on some reproductive aspects in rats

An aqueous extract of Hibiscus sabdariffa L. is a common beverage in many parts of the world. Reports on its effect on reproduction are conflicting, with anecdotal evidence that the plant is an aphrodisiac, while others report that it is estrogenic, and adversely affects spermatogenesis in rats. We have studied the effect of different concentrations of aqueous extracts of H. sabdariffa calyces (10%, 15% and 20%) used as drinking water for 10 consecutive weeks, and its anthocyanins (50, 100, 200 mg/kg for 5 days, orally) on the weight and histology of the testis, and on some biochemical constituents in testicular homogenates, in addition to the plasma concentrations of testosterone, luteinizing hormone and estradiol. The possible presence of an estrogenic effect of the extract and anthocyanins on the uteri of immature female rats was also tested. Neither the H. sabdariffa extract nor the anthocyanins significantly altered either testicular weight and histology, or uterus weight. Plasma concentrations of the three hormones studied, the testicular concentrations of protein, reduced glutathione and total cholesterol, and superoxide dismutase activity were all insignificantly affected by either the extract or the anthocyanins, except for a slight, but statistically significant, decrease in testicular protein concentration caused by the 15% aqueous extract when compared with controls. These results suggest that H. sabdariffa exerts no adverse effect on the male reproductive system. Consumption of H. sabdariffa aqueous extract inhibited the growth of the rats compared with the controls.