We propose two Markov chains for sampling (m + 1)-dimensional contingency tables indexed by {1, 2}m × {1, 2, . . . , n}. Stationary distributions of our chains are the uniform distribution and a conditional multinomial distribution (which is equivalent to the hypergeometric distribution ifm=1). Mixing times of our chains are bounded by ( 1 2 )n(n− 1) ln(N/(2m ))= ( 1 2 )n(n− 1) ln(dn/ ), where ...

an efficient protocol for the selective oxidation of primary alcohols to aldehydes withh5io6/v2o5 in ionic liquid [bmpy][pf6] has been developed. high yields of the products, mildreaction conditions and simple experimental procedure make this protocol complementary tothe existing methods. the catalyst can be reused for several times without obvious loss of thecatalytic activity.

the acetylation of various alcohols and phenols was performed successfully using acetic anhydride in the presence of citric acid coated magnetite nanoparticles as catalyst under solvent-free condition and at 45 °c. the catalyst showed high thermal stability and was recovered and reused at least 5 times without any considerable loss of activity. the present process is environmentally benign and ...

efficient and one-pot synthesis of 1,8-dioxo-octahydroxanthenes was described by knoevenagel condensation, michael addition and cyclodehydration of dimedone. this reaction was carried out through condensation of dimedone and various aromatic aldehydes in the presence of task-specific brønsted acidic ionic liquid under solvent free conditions. the catalyst could be recycled five times without si...

MCM-41-R-SO3H catalyzed one-pot synthesis of 1,8-dioxo-octahydroxanthenes is reportedunder reflux conditions. The catalyst is easily prepared, highly stable, very simple to handle andrecycled for five times without loss of significant activity

background: bone-specific alkaline phosphatase (bap) is synthesized by the osteoblasts and is presumed to be involved in the calcification of bone matrix, though its precise role in the formation process is unknown. the aim of the present study was to measure the bap activity in paget's and normal specimens by two different techniques. methods: total alp (tap) as well as bap activity-measu...

A new immobilized palladium-pyridine complex on γ-Fe2O3 magnetic nanoparticles was synthesized and characterized by SEM, TEM, TGA, ICP, XPS, XRD, FT-IR and CHN analysis. The catalytic activity of synthesized catalyst has been investigated in Heck, Suzuki and Sonogashira coupling reactions using a series of aryl halides. The catalyst was easily isolated from the reaction mixture by an external m...

this research has focused on isolation and characterization of a strain of bacillus sp. from alkaline soil, which was able to produce extracellular alkaline protease at phs ranging from 8 to 11 and temperatures of 20 to 50ºc. also the impact of different carbon andnitrogen sources were investigated. the yield and fold of enzyme purification was 24% and 50 times, respectively. molecular weight o...