PATENT ABSTRACTS 305

In aerobic wastewater treatment systems, such as sewage treatment, liquid in a channel spanned by a liquid-tight barrier is moved past the barrier by a liquid-gas contact pump, thus dissolving a gas in the liquid and creating a differential head that provides flow energy for moving the liquid in plug-type flow through the channel, which is preferably a continuous-flow pipeline or a circuit-flow oxidation ditch, without energy- wasteful vertical circulation. The barrier further provides a structure for mounting submerged static aerators or a draft tube, in combination with a surface aerator, such as a submerged tur- bine or surface-disposed impeller aerator, as the liquid-gas contact pump. The barrier is disposed at sufficient depth, when combined with static aerators or when telescopically attached to the draft tube of a floating surface aerator, to enable the liquid level to be selectively varied so that flow equalization to an oxidation ditch and wastewater storage therewithin are provided. Because of the plug-type flow and capability of maintaining it at 0.75-1.25 feet per second, a grit settling capability can be combined with aerobic digestive treatment within the oxidation ditch by placing a grit settling system slightly past the raw sewage inlet in a channel of the oxidation ditch. By employing a plurality of oxidation ditches, of which one is sequential used for clarification, and by incorporating a grit settling system within each of the oxidation ditches, the entire wastewater output from a large municipality, slaughterhouse, or poultry processing plant, for example, can be processed without preliminary or supplementary treatment in any other ap- paratus.

4532220

A S S A Y S F O R T H E D E T E R M I N A T I O N O F

C A R C I N O G E N I C I T Y

Sara Lavi, Kiryat Ono, Israel assigned to Yeda Research and Development Company Ltd

There is provided an assay for the determination of the carcinogenicity of chemical and physical agents, by exposing a selected line of tumor virus transformed cells to the agent to be tested and determining whether such exposure induces endogenous viral DNA replication in such cells, which induction is indicative of the car- cinogenicity of the tested agent by in situ hybridization. There is provided a kit for car- rying out such assay.

4533630

T O X I N S A N D A N T I B O D I E S O F C. D I F F I C I L E

Tracy D Wilkins, David M Lyerly

Mono-specific antibodies for each of toxin A and toxin B of C. difficile are produced and used in an assay for toxin A and toxin B, respectively. Purified toxin A of C. difficile is also produced.

~ 3 5 ~ 2

A P P A R A T U S F O R G R O W I N G M I C R O O R G A N I S M S

4532204

M U T A T I O N A S S A Y S I N V O L V I N G B L O O D C E L L S T H A T M E T A B O L I Z E T O X I C

S U B S T A N C E S

Charles Crespi, William Thilly assigned to Mas- sachusetts Institute of Technology

A line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylaseactivity) is disclosed. Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. Mutation assays using these cells, and other cells with similar characteristics, are also disclosed.

Hans Muller, Erlenbach, Switzerland assigned to Chemap AG

Growing of microorganisms takes place in a fer- menter in which simultaneously products of metabolism are separated and withdrawn by microfiltration with the aid of a diaphragm filter, and a suspension of microorganisms is stirred in the fermenter in the region immediately surroun- ding the diaphragm filter.

4537678

R O T A R Y B I O L O G I C A L C O N T A C T O R

Christopher Thissen assigned to Walker Process Corporation