A large number of fluids are used in formulating antifoams. In the 1950s a new class of antifoams, which was based on silicone fluids, was developed. The cost limitations of silicone antifoams were partially offset in a new set of antifoams developed in the 1960s. For protein-stabilized foam all the antifoams, including silicone/silica, are listed as being effective but will, naturally, have differing efficiencies. The active mixture preparation requires dispersion of hydrophobic silica or other finely divided solid in silicone oil. The preparation of silicone antifoams, although seemingly easy, is complicated by the fact that there are numerous variables, demonstrated empirically, that can affect antifoam performance. The viscosity of silicone oil used in the preparation of antifoam has a major effect on the overall effectiveness of the resulting composition. Antifoaming, using filled silicone oil-based antifoams, is a complex process that involves, at least, the following steps, all of which contribute to the overall performance.

Synopsis Objective Cosmetic dry skin often has a lower hydration level but a similar apparent barrier function, as measured by transepidermal water loss ( TEWL ), than that of the normal skin. To investigate the intrinsic difference in barrier property and moisture‐holding ability between the cosmetic dry and normal skin, we developed a new clinical and data analysis procedure based on sequential tape‐stripping with TEWL measurement, coupled with chemical analysis for protein and natural moisturizing factors ( NMF ) in the stratum corneum. Methods A clinical study consisting of 64 healthy Caucasian female subjects with normal and cosmetic dry skin was conducted according to our clinical and data collection protocols. After the baseline visual dryness assessment, 20 tape‐strips were placed and removed on each test site using D‐Squame tapes. TEWL was measured at baseline and after the 5th, 10th, 15th and 20th tape‐strips. All tapes were analysed for protein mass via chemical extraction and the Pierce BCA protein assay, as well as using an infrared densitometry device SquameScan 850A. The stratum corneum thickness and barrier quality (water transport resistance per thickness of the stratum corneum) were decoupled from the apparent barrier function using the TEWL and protein data. Results A linear relationship between 1/ TEWL and cumulative protein removal was observed for both normal and cosmetic dry skin. However, the slope of the linear relation was significantly steeper for normal skin, and significantly more protein was removed from cosmetic dry skin. The results showed that on average, the barrier quality of the stratum corneum of the normal skin is about 40% higher than that of the dry skin, whereas the stratum corneum of the dry skin is about 30% thicker than that of the normal skin. In addition, the amount of SC removal in sequential tape‐stripping is generally non‐uniform. Conclusion Our results demonstrated that there are characteristic differences in the barrier property between normal and cosmetic dry skin. In comparison to the normal skin, the stratum corneum of the cosmetic dry skin is considerably thicker, however, with a lower barrier quality. The results also showed that the amount of the SC removal in sequential tape‐stripping is generally non‐uniform. Therefore, the number of tape strips is not a good indicator for the tape‐stripping depth.

SynopsisObjectiveIn a previous paper (Lu et al., International Journal of Cosmetic Science, in press), we reported that in comparison with normal skin, cosmetic dry skin characteristically has a thicker stratum corneum (SC) with weaker barrier quality. Our goal here was to obtain a more complete picture of the difference between normal and cosmetic dry skin, by further analysing the data collected from the same clinical study to address two additional aspects of skin: the amount and depth profile of natural moisturizing factor (NMF) and the cohesivity of the SC.MethodThe SC samples were collected by sequential tape stripping in a clinical study consisting of 64 healthy Caucasian female subjects with either normal or cosmetic dry skin. Protein and free amino acids (FAA) on tape strips were extracted and analysed using high‐throughput methods. The level of pyrrolidone carboxylic acid (PCA), the prominent component of NMF, was detected using HPLC analysis.ResultsIt was found that dry skin had significantly lower ratios of FAA/protein and PCA/protein across the stripped SC depth, corresponding to a lower hydration level compared with the normal skin. Our results indicated that filaggrin to FAA hydrolysis occurred deeper in dry skin and at a lower level compared with normal skin. In addition, the mass of proteins stripped from dry skin subjects was significantly higher than that from the normal skin counterpart, especially for the first 10–12 tape strips.ConclusionOur results showed that, compared with normal skin, cosmetic dry skin had a lower NMF level across the SC depth and a lower cohesivity. Such results suggested that NMF levels are critical for cosmetic skin conditions, and lower NMF production may be associated with dry skin. In addition, the NMF level and its depth profile and the SC cohesivity are useful clinical end points for assessing the efficacy of dry skin treatments such as skin moisturizers.

Surfactant abstraction by reservoir lIIinerals is goverlled by a nulllber of interacting pI,enomena owulg to the heteroqelltlity of the reservoir rock, the c~lex nature of the surfact.nts use.!, as well as the .ulticonponent nature of the reservoir fluid resulting fr~ the presence of inorqanics, co-surfactants, oil and polyJ:lers. The role of these factors in influencing die surfactant abstraction behavior is exaained in this work. The major phen~na considcred as resr~nsible for deteraininq the surfactant loss are discussed.

In xerotic skin, the proteolysis of desmosomes is reduced leading to the accumulation of corneocytes on the surface of the skin. The effect of proteases applied topically to soap-induced xerotic skin was evaluated using a five-point visual scale. The visual scaling associated with soap-induced xerosis could be ameliorated by the topical application of exogenous protease. Bovine pancreatic chymotrypsin, papain, and a bacterial protease from Bacillus licheniformis were all capable of facilitating the reduction in visual scaling in a short time. Alcalase and Optimase, both broad specificity alkaline bacterial proteases, were the most weight-efficient at delivering this clinical effect. The reduction in scaling could be achieved either by occluded application of an aqueous enzyme solution or by a two-step unoccluded application first of an aqueous enzyme solution followed by a commercial moisturizer. Morphological and immunological analysis of bacterial enzyme-treated skin revealed that topically applied protease specifically induced the degradation of the desmosomes thereby promoting desquamation. These results indicate that topical application of protease can significantly and rapidly reduce the visual scaling associated with soap-induced xerosis by promoting desmosome degradation within the corneocyte clumps.

apparent as A1 content increases. 4. Boron-containing dimers are less stable than their Al-containing analogues. The H form of the boron dimer is the most unstable species. Its hydroxyl group appears less polar than the corresponding one in the A1 dimer. These observations support the finding that Br~nsted sites in crystalline borosilicates are weak compared to those of their A1 analogues. They suggest in addition that tetrahedrally coordinated boron in the hydrogen form of 1987, 91, 148-150

Alpha-hydroxy acids are effective agents for the treatment of skin xerosis and it is known that, following treatment with lotions containing D,L-lactic acid, the stratum corneum prevents xerosis more effectively. To date, the relative efficacy of the different isomers of lactic acid has not been evaluated and the mode of action of lactic acid in improving stratum corneum resilience is not known. The objective of the present studies was to determine the effects of lactic acid isomers on keratinocyte ceramide biosynthesis, stratum corneum barrier function and the resistance of the stratum corneum to the appearance of skin xerosis. In vitro, lactic acid enhanced the production of ceramides by keratinocytes. L-Lactic acid was more effective than the D isomer (300% increase vs 100% increase). Carbon label from lactic acid was incorporated into all keratinocyte lipid species and a greater incorporation of label into ceramides was achieved with L-lactate than with D-lactate. In vivo, lactic acid increased the levels of stratum corneum ceramides. Whereas, lotions containing L-lactic acid resulted in the greatest increase (48% increase) followed by D,L-lactic acid (25% increase), D-lactic acid had no effect on stratum corneum ceramide levels. The increases in stratum corneum ceramide levels following lactic acid treatment also led to improvements in stratum corneum barrier function, measured by transepidermal water loss following a challenge to the skin with SLS and in the regression phase of a moisturization efficacy study. Significant improvements in barrier function and resistance to the appearance of skin xerosis were observed following L-lactic acid and D,L-lactic acid, but not following D-lactic acid treatment. From these results we believe that lactic acid, particularly the L isomer, stimulates ceramide biosynthesis leading to increased stratum corneum ceramide levels which results in superior lipid barrier and a more effective resistance against xerosis.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilicone "Superwetters"E. D. Goddard, K. P. Ananthapadmanabhan, and P. ChandarCite this: Langmuir 1995, 11, 4, 1415Publication Date (Print):April 1, 1995Publication History Published online1 May 2002Published inissue 1 April 1995https://pubs.acs.org/doi/10.1021/la00004a059https://doi.org/10.1021/la00004a059research-articleACS PublicationsRequest reuse permissionsArticle Views135Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Specialized lipids found in the stratum corneum, namely ceramides, have been shown to have beneficial skin properties due to their lipid bilayer-forming potential in the presence of cholesterol and fatty acids. We were interested in determining whether other bilayer-forming lipids, such as phospholipids, could deliver similar benefits and how these benefits compare with common moisturizer ingredients such as petrolatum and glycerol. We investigated a bilayer-forming mixture of phospholipids, cholesterol, and fatty acid for its effectiveness in treating soap-induced winter xerosis in double-blind, fully randomized clinical trials in which dryness on the dorsal aspect of the hands was visually assessed using a seven-point grading scale. Sixty-six healthy Caucasian women aged over 25 underwent a one-week soap ''dry-down'' and were treated for two weeks with twice-daily product applications in balanced treatment groups (N = 11). Treatments were compared statistically using repeated Wilcoxon rank sum tests (critical significance level of 5%). Examination of improvements in xerosis in vivo established that emulsions of phospholipids, cholesterol, and stearic acid alone, or thickened solutions of glycerol alone, did little to alleviate skin xerosis. When lipids and glycerol were combined, however, the emulsions acted in a synergistic way and reduced skin xerosis significantly and rapidly. In contrast, when phospholipids were replaced with petrolatum in che emulsions, the race of xerosis alleviation was reduced, which implies that the bilayer-forming capabilities of phospholipids may be important in delivering optimal skin benefit. These studies demonstrate that lipids with bilayer-forming capabilities such as phospholipids can rapidly alleviate skin xerosis when combined with glycerol.

This work reports an investigation of the solution, interfacial and special wetting properties of a group of three silicone surfactants using surface tension, wetting, adsorption, fluorescence and fluorescence decay techniques. Aqueous solutions of two of these surfactants exhibit a c.m.c. type break in the surface tension versus concentration plot. Fluorescence and turbidity measurements show that for one (SS1) the break corresponds to the formation of well dispersed droplets rather than micelles. A second surfactant, SS2, forms micelles in solution of aggregation number around 30 which is significantly lower than that for conventional surfactant micelles. SS1, with a compact hydrophobic group and a long polyether tail, reduces the surface tension of water to 20.5 mN m−1 and exhibits a unique ability to wet low energy surfaces such as polyethylene. Interestingly, fluorocarbon surfactants which can lower the surface tension of water even further do not wet polyethylene as efficiently. The special wetting properties of SS1 are attributed to a variety of factors, i.e., its unique structure, ability to lower the liquid-air surface tension to extremely low values, fast kinetics of adsorption at the liquid-air and solid-liquid interfaces, high affinity of the surfactant for low energy surfaces, and favorable orientation and structure of its adsorbed molecules.

Surfactant formulations that are used in enhanced oil recovery consist of mixtures of various components. We have continued studies on mixtures of an anionic surfactant, C/sub 8/benzenesulfonate, and a nonionic surfactantt. C/sub 12/EO/sub 8/alcohol. Adsorption data on alumina and silica show that strong interactions between the two surfactants occur. On alumina on which the nonionic does not absorb by itself the presence of small amounts of adsorbed sulfonate was sufficient to cause significant adsorption of ethoxylated alcohol. On silica sulfonate did not absorb by itself but only did so in the presence of alcohol. Interactions between surfactants were quantified using the regular mixing model. Interaction parameters between -3 and -5 were determined at the liquidair interface in mixed micelles from surface tension data for different surfactant compositions. Work is focused on directly measuring thermodynamic quantities using microcalorimetry. Surfactant structural effects were also studied. A series of branched C/sub 14/benezenesulfonates emphasizes characterization along with adsorption measurements. Results showed major influences in addition to that of chain lenth and chain branching due to the position in the benzene ring of the longer alkyl chain in relation to that of the sulfonate group. 43 refs., 54 figs., 3 tabs

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFluorescence probe investigation of anionic polymer-cationic surfactant interactionsPrem Chandar, P. Somasundaran, and N. J. TurroCite this: Macromolecules 1988, 21, 4, 950–953Publication Date (Print):April 1, 1988Publication History Published online1 May 2002Published inissue 1 April 1988https://pubs.acs.org/doi/10.1021/ma00182a018https://doi.org/10.1021/ma00182a018research-articleACS PublicationsRequest reuse permissionsArticle Views794Altmetric-Citations120LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExcimer fluorescence determination of solid-liquid interfacial pyrene-labeled poly(acrylic acid) conformationsPrem Chandar, P. Somasundaran, Nicholas J. Turro, and Kenneth C. WatermanCite this: Langmuir 1987, 3, 2, 298–300Publication Date (Print):March 1, 1987Publication History Published online1 May 2002Published inissue 1 March 1987https://pubs.acs.org/doi/10.1021/la00074a026https://doi.org/10.1021/la00074a026research-articleACS PublicationsRequest reuse permissionsArticle Views190Altmetric-Citations49LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts