68 JOURNAL OF COSMETIC SCIENCE higher than that of the non-crosslinked sample. Moreover, a suitable crosslinking ratio was confirmed. The viscosity thickening effects of the microgel under various pH, salt concentration, and alcohol concentration conditions were also investigated. The study revealed that the microgel can be considered as a multi-purpose viscosity thickener for cosmetics. Shear Viscosity of Concentrated Spherical Silica Suspension --Effect of Polymethylsiloxane Surface Treatment- Akio Hamamoto* * , Nobuhiro Nogami * * , Susan J. Muller* * * Daito Kasei Kogyo Co., Ltd. * *, Department of Chemical Engineering, University of California-Berkeley* * * In determining the formulation of cosmetics dispersed in powder, it is very important to discover the rheological behavior of the suspension. In the case of concentrated particle suspension, it is known that the remarkable behavior of the rheology, which is different from the dilution system, is shown in ways such as shear thickening. In this report, the rheological behaviors of a concentrated spherical silica particle system were investigated in terms of particle-particle and particle-medium interaction. In the case of an aqueous medium, shear thickening occurred under certain conditions. It is noteworthy that the pH of an aqueous medium far from the isoelectric point (pH=4) of silica particles resulted in a decrease in shear viscosity 71 due to an increase in the double-layer repulsion. In addition, the rheological behaviors of suspension using the silica particles, which were treated with polydimethylsiloxane and methylhydrogen polysiloxane as the solvent system, were investigated. Shear thickening disappeared in all of the solvent systems, and polydimethylsiloxane system showed lower viscosity than the methylhydrogen polysiloxane system. The surface treatment, which affects the shear viscosity, is changed not only by the particle-particle interaction but also the particle-medium interaction.

J. Connet. Sci., 57, 69-70 Qanuary/February 2006) Abstracts International Journal of Cosmetic Science Vol. 27, No. 6, 2005* Rapid and Accurate Identification of Microorganisms Contaminating Cosmetic Products Based on DNA Sequence Homology Y. Fujita*, H. Shibayama*, Y. Suzuki*, S. Karita and S. Takamatsu *Toyo Beauty Co., Ltd, Osaka, Japan, Department of Sustainable Resource Sciences, Faculty of Bioresources, Mie University, Tsu, Japan and Laboratory of Plant Pathology, Faculty of Bioresources, Mie University, Tsu, Japan The aim of this study was to develop rapid and accurate procedures to identify microorganisms contaminating cosmetic products, based on the identity of the nucleotide sequences of the internal transcribed spacer (ITS) region of the ribosomal RNA coding DNA (rDNA). Five types of microorganisms were isolated from the inner portion of lotion bottle caps, skin care lotions, and cleansing gels. The rDN A ITS region of microorganisms was amplified through the use of colony-direct PCR or ordinal PCR using DNA extracts as templates. The nucleotide sequences of the amplified DNA were determined and subjected to homology search of a publicly available DNA database. Thereby, we obtained DNA sequences possessing high similarity with the query sequences from the databases of all the five organisms analyzed. The traditional identification procedure requires expert skills, and a time period of approximately 1 month to identify the microorganisms. On the contrary, 3-7 days were sufficient to complete all the procedures employed in the current method, including isolation and cultivation of organisms, DNA sequencing, and the database homology search. Moreover, it was possible to develop the skills necessary to perform the molecular techniques required for the identification procedures within 1 week. Consequently, the current method is useful for rapid and accurate identification of microorganisms, contaminating cosmetics. Influence of Cosmetics on Emotional, Autonomous, Endocrinological, and Immune Reactions P. Po"ssel*, S. Ahrens and M. Hautzinger *Department of Psychology and Human Development, Peabody College #512, Vanderbilt University, Nashville, TN, U.S.A. and _Department of Clinical and Physiological Psychology, University of Tuebingen, Tuebingen, Germany Recent findings indicate that cosmetics increase positive valence of emotions and thereby influence the autonomous nerve system. Other studies showed the effects of emotions on the endocrinological and the immune system. Based on this preliminary conclusion, the aim of the present study was to prove whether cosmetics are able to decrease the level of the stress hormone cortisol and strengthen the immune system. Four slides of made up or unvarnished women each, integrated in another 16 slides each of equivalent valence and arousal, were presented to 60 women. During stimulus presentation, subjective (valence), autonomous (heart rate), endocrinological (salivary cortisol) as well as immunological reactions [ secretory immunoglobulin A (sigA)] were recorded. As expected subjective ratings concerning the slides of made up women reported more positive valence than those concerning unvarnished women. Furthermore, heart rate decreased under presentation of made up women, which indicates the positive influence of these slides on the autonomous nerve system. Furthermore, in half of the volunteers a decrease of cortisol and an increase of sigA level while presenting the made up women was measurable in contrast to the presentation of unvarnished women. Maybe this is due to a short presentation time and the endocrinological as well as the immune system can be hardly influenced that quick. Another explanation could be that the volunteers were in part so called psychophysiological non-responders who show no reaction to emotional stimuli in the * These abstracts appear as they were originally published. They have not been edited by the journal of Cosmetic Science. 69