nano sulfated titania was tested as solid acid heterogeneous catalyst for the synthesis of 4-(trifluoromethyl) coumarin and coumarin derivatives under solvent-free condition. factorial design evidenced a positive effect of reaction temperature, amount of catalyst, and solvents.  this nano-sized sulfated titania has been prepared by a sol-gel hydrothermal process. the prepared sulfated titania s...

a condensation of various isatins with indole derivatives has been carried out in the presence of 1,3-dibromo-5,5-dimethylhydantoin (dbdmh) as catalyst at 50 °c in ethanol in order to form 3,3-bis(indolyl) oxindoles. the products were obtained within 20-90 min by 70-96% yields. the efficacy of the procedure has been confirmed by catalyzing the condensation reaction of pyrrole which was used as ...

the aim of this research is to study ni2+ supported on hydroxyapatite-core-shell magnetic γ-fe2o3 nanoparticles (γ-fe2o3@hap-ni2+) as a green and recyclable catalyst for the biginelli reaction under solvent-free conditions. one-pot multi-component condensation of 1,3-dicarbonyl compounds, urea and aldehydes at 80 oc affords the corresponding compounds in high yields and in short reaction times ...

embryonic stem cells (escs) as pluripotent stem cells have the potential to give rise to all three germ layer cells. also, these cells have the self-renewing ability. escs could differentiate into most of cell lineages. lymphocytes generated from hematopoietic stem cells. we designed a feeder free culture condition to generate lymphoid lineage cells from escs. we demonstrated that il-7 plays cr...

an efficient and chemoselective procedure for the preparation of 1, 1-diacatates (acylals) from various aldehydes with acetic anhydride in the presence of brønsted acidic ionic liquid [msei]cl as a reusable catalytic system under solvent-free condition at room temperature and short periods of times with excellent yields will be described. the catalyst was easily separated in simple work-up and ...

We prove that if the given compact set K is convex then a minimizer of the functional I(v) = ∫ BR |∇v|dx + Per({v > 0}), 1 < p < ∞, over the set {v ∈ H 0 (BR)| v ≡ 1 on K ⊂ BR} has a convex support, and as a result all its level sets are convex as well. We derive the free boundary condition for the minimizers and prove that the free boundary is analytic and the minimizer is unique.

We show that a minimal disk satisfying the free boundary condition in a constant curvature ball of any dimension is totally geodesic. We weaken the condition to parallel mean curvature vector in which case we show that the disk lies in a three dimensional constant curvature submanifold and is totally umbilic. These results extend to higher dimensions earlier three dimensional work of J. C. C. N...

a convenient, one-pot method for the synthesis of diazonium salt has been developed by the sequential diazotization of aromatic amines with nano2, polymer- supported periodic acid (ppia) and 2-naphthole under solvent-free conditions at room temperature. by using this method, several types of aromatic amine, containing electron-withdrawing and electron-donating groups, were rapidly converted to ...