Evaluation of lithium separation by dispersive liquid–liquid microextraction using benzo-15-crown-5

In this article a dispersive liquid?Cliquid microextraction method was applied for evaluation of lithium separation from aqueous solution. Benzo-15-crown-5 (B15C5) was used as a chelating agent prior to extraction. An appropriate mixture of disperser solvent and extraction solvent were added rapidly into the aqueous sample containing lithium ion; as a result, a cloudy solution was formed which consisted of fine droplets of extraction solvent dispersed entirely into aqueous phase. The mixture was centrifuged and the lithium complex with B15C5 was sedimented at the bottom of the conical sample holder. Then, 2.0?mL of enriched phase containing lithium complex was used for determination of lithium ion by flame atomic absorption spectrometry. The conditions for the microextraction performance were investigated. Under the best optimized conditions, the accepted recovery factors for the lithium obtained, ranged from 37.24 to 99.63?%. Furthermore, high preconcentration factors (7.46?C19.93) were also achieved. The relative standard deviation for three replicate measurements of 0.127?mg?L^?1 of lithium was 2.83?%.     

Highly efficient and convenient Strecker reaction of carbonyl compounds and amines with TMSCN catalyzed by MCM-41 anchored sulfonic acid as a recoverable catalyst

MCM-41 anchored sulfonic acid (MCM-41–SO₃H) was found to be a highly efficient and recoverable heterogeneous catalyst for the three-component Strecker reaction of aldehydes or ketones and diverse amines using trimethylsilyl cyanide (TMSCN) to afford the corresponding α-amino nitriles under mild conditions in high to quantitative yields. The simple experimental procedure along with easy recovery and reusability of the catalyst has led to development of a clean and environmentally friendly approach for the synthesis of α-amino nitriles.     

Removal of malaria-infected red blood cells using magnetic cell separators: A computational study

High gradient magnetic field separators have been widely used in a variety of biological applications. Recently, the use of magnetic separators to remove malaria-infected red blood cells (pRBCs) from blood circulation in patients with severe malaria has been proposed in a dialysis-like treatment. The capture efficiency of this process depends on many interrelated design variables and constraints such as magnetic pole array pitch, chamber height, and flow rate. In this paper, we model the malaria-infected RBCs (pRBCs) as paramagnetic particles suspended in a Newtonian fluid. Trajectories of the infected cells are numerically calculated inside a micro-channel exposed to a periodic magnetic field gradient. First-order stiff ordinary differential equations (ODEs) governing the trajectory of particles under periodic magnetic fields due to an array of wires are solved numerically using the 1st to 5th order adaptive step Runge-Kutta solver. The numerical experiments show that in order to achieve a capture efficiency of 99% for the pRBCs it is required to have a longer length than 80 mm; this implies that in principle, using optimization techniques the length could be adjusted, i.e., shortened to achieve 99% capture efficiency of the pRBCs.     

Numerical solutions of the generalized Kuramoto-Sivashinsky equation using B-spline functions

A numerical technique based on the finite difference and collocation methods is presented for the solution of generalized Kuramoto-Sivashinsky (GKS) equation. The derivative matrices between any two families of B-spline functions are presented and are utilized to reduce the solution of GKS equation to the solution of linear algebraic equations. Numerical simulations for five test examples have been demonstrated to validate the technique proposed in the current paper. It is found that the simulating results are in good agreement with the exact solutions.     

Phosphine-free conversion of alcohols into alkyl thiocyanates using trichloroisocyanuric acid/NH4SCN

A convenient and efficient phosphine-free procedure for the one-pot conversion of primary,secondary and tertiary alcohols into the corresponding alkyl thiocyanates or alkyl isothiocyanates is described using trichloroisocyanuric acid/NHUSCN.     

Applications of calixarene nano-baskets in pharmacology

Calixarene nano-baskets enable to encapsulate the guest drugs and show different biological activities. This review deals with the behavior of calixarene-based drugs and illustrates their potentials in the pharmacological sciences. The role of calixarene’s scaffolds and substitutions in aspects of anti-cancer, anti-mycobacterial, anti-proliferativity, catalytic and inhibitory activities as well as solubility control, drug analysis, drug purification, drug supports and structural studies is reviewed.