Research on strategies for reducing the irritability of potassium cocoyl glycinate in cleansing

Background:Potassium cocoyl glycinate,a kind of amino acid surfactant,is widely used as major component for facial cleansing.However,the interaction between surfactants and compounds in the stratum corneum has been suggested as a contributing factor to their potential skin irritancy.Objective:This study aimed to the effects of adding surfactants,polymers,lipids and active substances on diminishing skin irritation caused by potassium cocoyl glycinate.Materials and methods:Zein test and Hemolysis test enabled the identification of irritation to proteins and cells in the studied binary systems.The critical micelle concentration(CMC)was evaluated by the surface tension method.The power of the analyzed polymers to diminish irritation of potassium cocoyl glycinate was represented by the reduction rate.Results:(1)Amphoteric surfactants and nonionic surfactants are effective at reducing the irritation of potassium cocoyl glycinate in some cases by reducing CMC;(2)Addition of polymers to the potassium cocoyl glycinate solutions improves its safety of use.Hydroxypropyl methylcellulose could reduce the irritation by 88.63%;(3)Combining most lipids can assist in declining the irritation,Lppg-28-Buteth-35 could inhibit the irritation of red blood cells by 16.52%;(4)The effects of active substances varied,hydrolyzed sodium hyaluronate results in a significant reduction in irritation to cells.Conclusion:In facial cleansers based on potassium cocoyl glycinate,supplying co-surfactant,polymers,lipids and active substances can reduce the irritation to some extent,however,the effects are various.

Seismic Fragility Analysis of Long-Span Bridge System with Durability Degradation

An offshore long-span continuous rigid-frame bridge is taken as an example to study the effect of degradation of bond-slip behavior on the seismic performance of bridges in an offshore environment during a service period.On the basis of a numerical simulation analysis using the OpenSeeS platform,the influence of durability degradation of concrete carbonization,steel corrosion,and degradation of bond-slip performance is considered collectively using incremental dynamic analysis method to examine the time-varying seismic fragility of the offshore bridge.Results show that when bond slip is considered,the exceedance probability of the bridge components and the system increases significantly,and the durability degradation caused by concrete carbonization and chloride ion erosion in the whole life cycle increases the seismic response of the bridge structure.The results of the proposed time-varying seismic fragility analysis indicate that,considering the degradation of bond-slip behavior of reinforced concrete after the durability degradation of materials,the exceedance probability of the pier,bearing,abutment,and system increases with the extension of service period and the increase in seismic strength under earthquake action.In addition,with the extension of service time,the effect of bond slip on the seismic fragility of components and system gradually decreases.