The Lf-unit, which is used in the control of diphtheria and tetanus toxoid production and in some countries also to follow immunization of horses for production of antitoxins, has hitherto been defined by means of antitoxin preparations. A diphtheria toxoid and a tetanus toxoid preparation, both freeze-dried, were examined in an international collaborative study for their suitability to serve a...

years prior to the activated sludge researches which date from the work of Fowler and Mumford on the bacterial clarification of sewage employing a new iron bacterium, 1 MyQuite recently Heukelekian (1941) has reviewed the present state of our knowledge of mechanical flocculation and bioflocculation of sewage, and concluded that the flocculation is brought about both by physical and biological a...

This work presents a systematic study of asphaltene pre-aggregation phenomena in the absence and presence ionic liquids (ILs) from family 1-alkyl-3-methylimidazolium by molecular dynamics simulations. The effects alkyl chain length cation (studying ILs with chains between C4 C10) dimension anion (testing chloride bromide) on aggregation behavior asphaltenes have been studied. To correlate resul...

Since the publication of the original complementfixation test for syphilis by Wassermann, Neisser, Bruck, and Schucht (1906) and the publication of the flocculation test of Porges and Meier (1908), innumerable modifications have been described for the improvement of both diagnostic methods. The technical complexity of the former furnished an incentive for the development of the latter. Yet, des...

A comparison is made of tests for thyroglobulin antibody, using gel diffusion, electroprecipitin, bentonite flocculation, tanned red cell agglutination, and latex slide agglutination techniques on sera from cases of Hashimoto's disease and other thyroid disorders. Any increase in gamma globulin was also noted from the serum electrophoretic pattern. The gel diffusion and electroprecipitin tests ...

Flocculation of precipitated calcium carbonate (PCC) was monitored using light diffraction spectroscopy (LDS). Four cationic polyacrylamides of high molar mass and with different degrees of branching, all copolymers of acrylamide (AM) and acryloyloxyethyltrimethyl ammonium chloride (Q9), were tested. LDS supplied information about the kinetic curves for flocs growth and also for the flocs struc...

Yeast flocculation is a community-building cell aggregation trait that is an important mechanism of stress resistance and a useful phenotype for brewers; however, it is also a nuisance in many industrial processes, in clinical settings, and in the laboratory. Chemostat-based evolution experiments are impaired by inadvertent selection for aggregation, which we observe in 35% of populations. Thes...

The flocculation of silica by coagulation with hydrolyzed aluminum salt and the flocculation of aluminum salt in the presence of organic acids at pH 6.5 have been studied by using Small-Angle X-ray Scattering. The flocculation of silica at pH 4.5 by isolated All3 is very similar to its flocculation by nonhydrolyzable salt as Ca++; the fractal dimension Df of the flocs is 2.20. At pH 7.5, Al13 i...

Harvesting of microalgae Scenedesmus sp. (strain A1) using the natural polymer chitosan was investigated. Different chitosan concentrations, i.e., 10, 20, 40, 60 and 80 ppm were used in the pH range 6 to 10 and cultural cell densities values equivalent to 1, 2 and 3 abs680. Without the addition of chitosan, the increase in pH of the culture led to limited cell sedimentation. The addition of chi...

three series of a polydispersed system of sulfadiazine and sulfamerazine mixture were prepared, and effect of three inorganic electrolytes on flocculation of this system was studied. we have found the appropriate flocculating agent and also its necessary concentration. results obtained have shown that there is a relation between flocculation and sedimentation volume, but the hard cake formed wh...