The PCT leaves each Contracting State free to prescribe such substantive conditions of patentability as it desires. This is particularly true of what constitutes “prior art.” However, since the requirements of prior art as defined in the PCT and its Regulations for the purposes of the PCT National Phase are generally as strict as, or stricter than, those defined in any national law, the chances of unpleasant surprises by way of previously uncited prior art references being raised during the PCT National Phase are substantially reduced. On the other hand, the PCT does not prevent any national law from requiring the applicant to furnish, in the PCT National Phase, evidence in respect of any substantive condition of patentability prescribed by that law.
We chose to evaluate diatomaceous earth because of its purported effectiveness even when applied by do-it-yourselfers. Nonetheless, it’s long been known that DE is not the most potent of desiccants (Ebeling 1961, 1971). More efficacious, especially under field conditions, are silica aerogels contained in products such as Drione, Tri-Die and CimeXa. (See related article above.) Silica gels are synthetically produced compounds comprised of percent silicon dioxide. Small bags of the desiccant are often packaged with electronics to prevent accumulation of moisture during shipping and storage. Forms of silica gel used for pest control are light fluffy powders comprised of extremely small particles. The tiny particles have an electrostatic charge that helps them adhere to insects crawling over treated surfaces. Instead of acting as an abrasive, silica gel functions somewhat like a sponge to absorb the cuticular waxes of insects onto the dust particles. Silica gel-type desiccants with high adsorptive capability are generally more effective than abrasive dusts such as DE, especially under practical use conditions (Ebeling 1961, 1971; Subramanyam and Roesli 2000).