We have investigated various silica zeolites using density functional theory with periodic supercells, plane waves, and pseudopotentials. These zeolitic phases include silica sodalite, chabazite, mordenite, silica LTA, and silicalite. Atom-level geometries, elastic properties, and cohesive energies are presented. Although the zeolites exhibit a wide range of Si-O-Si angles and densities, the co...

Treatment of thiacalix[8]arene (3.8H) with KH in THF, followed by recrystallization from methanol, affords an adduct of [K4(3.4H)].8MeOH as a pale yellow crystal (4), which shows highly-extensive coordination that gives rise to a zeolitic structure. An adduct of 4 gives apohost [K4(3.4H)] with the loss of methanol, which can adsorb such gaseous organic guest molecules as methanol and benzene. A...

Introduction: Researchers have recently described a relationship between food additives and immune system responses. A decline in immune response has also been observed in people who are in contact with food additives, such as preservatives and flavours found in different foods. Objectives: The objective of the present study was to investigate the in vitro effect of food additives, such as vani...

This paper reviews the use of additives to reduce odor and ammonia (NH3) emissions from livestock wastes. Reduction of NH3 volatilization has been shown to be possible, particularly with acidifying and adsorbent additives, and potential exists to develop further practical and cost-effective additives in this area. Masking, disinfecting, and oxidizing agents can provide short-term control of mal...

Pyrolysis of high impact polystyrene (HIPS) waste has been investigated under different process parameters, such as temperature, heating rate and types of zeolitic catalysts to produce valuable liquid products. Liquid, gas and coke as products of pyrolysis and aromatic, naphthene, olefin and paraffin as liquid components were obtained and their molecular weight distributions were studied with c...

This is a comprehensive review of the recent progresses made in the field of zeolite membranes. It describes zeolitic materials and methods of membrane fabrication, followed by a summary of applications for gas separation, pervaporation and separation of liquid mixtures. Special attention is called to polymer mixed matrix membranes (MMMs) and membranes based on metal organic frame works (MOFs)....

there has been a great increase in the consumption of various food additives in recent years. the purpose of this study was to identify the incidence of sensitization to food additives by using skin prick test in patients with allergy and to determine the concordance rate between positive skin tests and oral challenge in hypersensitivity to additives. this cross-sectional study included 125 (fe...

The hallowed notion that oxidative damage causes aging and that vitamins might preserve our youth is now in doubt