PubMed Health⌕ Search

Biomedical subjects

Paul S Wheatley

Publications and source records attributed to Paul S Wheatley.

6 recordsLinked to original sources
PubMed2006

NO-releasing zeolites and their antithrombotic properties.

Transition metal-exchanged zeolite-A adsorbs and stores nitric oxide in relatively high capacity (up to 1 mmol of NO/g of zeolite). The stored NO is released on contact with an aqueous environment under biologically relevant conditions of temperature and pH. The release of the NO can be tuned by altering the chemical composition of the zeolite, by controlling the amount of water contacting the zeolite, and by blending the zeolite with different polymers. The high capacity of zeolite for NO makes it extremely attractive for use in biological and medical applications, and our experiments indicate that the NO released from Co-exchanged zeolite-A inhibits platelet aggregation and adhesion of human platelets in vitro.

Fibrinolytic Agents↗
PubMed2004

Ionic liquids and eutectic mixtures as solvent and template in synthesis of zeolite analogues.

The challenges associated with synthesizing porous materials mean that new classes of zeolites (zeotypes)-such as aluminosilicate zeolites and zeolite analogues-together with new methods of preparing known zeotypes, continue to be of great importance. Normally these materials are prepared hydrothermally with water as the solvent in a sealed autoclave under autogenous pressure. The reaction mixture usually includes an organic template or 'structure-directing agent' that guides the synthesis pathway towards particular structures. Here we report the preparation of aluminophosphate zeolite analogues by using ionic liquids and eutectic mixtures. An imidazolium-based ionic liquid acts as both solvent and template, leading to four zeotype frameworks under different experimental conditions. The structural characteristics of the materials can be traced back to the solvent chemistry used. Because of the vanishingly low vapour pressure of ionic liquids, synthesis takes place at ambient pressure, eliminating safety concerns associated with high hydrothermal pressures. The ionic liquid can also be recycled for further use. A choline chloride/urea eutectic mixture is also used in the preparation of a new zeotype framework.

Journal Article↗
PubMed2004

A severely interrupted germanate zeolite framework synthesised from isolated double four-ring units.

A new germanate zeolite framework has been prepared by first determining the reaction conditions required to prepare a molecular analogue of the zeolite double four-ring secondary building unit and then altering the conditions so as to encourage condensation of these units. The resultant material is a severely interrupted solid showing an unusual two dimensional channel system. It is also one of the most open frameworks yet discovered. The material was characterised using single crystal X-ray diffraction at a synchrotron source and solid state magic angle spinning NMR.

Journal Article↗