Probability Density Functional Method of Enzyme Effect on Denatured Protein Soil.

Protein soils must be removed for both appearance and hygienic reasons. They are denatured by heat treatment or bleaching and cleaned using enzymes. Among the various types of protein soils, blood soils are the most noticeable and known to be denatured by heat and bleaching by oxidation. We verified herein that the detergency of heat and oxidatively denatured hemoglobin is greatly improved by the enzyme immersing treatment in the detergency with SDS and can be analyzed using the probability density functional method. The probability density functional method evaluates the cleaning power by assuming that the adhesion and cleaning force of soils are not uniquely determined, but instead have a distribution in intensity, with a usefulness that had recently been demonstrated. This analytical method showed that the cleaning power of the enzyme immersing treatment improved when the soil adhesive force was decreased due to denatured protein degradation, even though the cleaning power of the SDS remained unchanged, and the values were consistent with those in the cleaning test. In conclusion, the probability density functional method can be used to analyze enzymatic degradation of denatured protein soils and the resulting changes in their detergency.

Analysis of Cleaning Power Using New Cleaning Kinetics and Interfacial Science Studies on Aquatic Toxicity of Surfactants.

Studies devised through the fusion of cleaning and environmental sciences can be summarized as follows: new cleaning kinetics applying a probability density function and a surface chemical approach to the aquatic toxicity of surfactants. Cleaning power analysis using the probability density functional method combines conventional cleaning kinetics using a first-order reaction equation with a risk analysis method using a probability density function. It is possible to analyze the cleaning mechanism from the obtained parameter values. It is also possible to determine whether the interaction between two different cleaning elements corresponds to a synergistic, additive, or offsetting effect. Studies on the aquatic toxicity of surfactants have focused on the surface tension at which surfactants exhibit toxicity, changes in toxicity due to water quality, and biodegradation, and the presence of adsorbed substances have been identified.

Improving the Removability of Mud Stains by Combining a Homopolymer and a Chelating Agent.

To improve the detergency of mud stains without triphosphate, we developed a new composition that enhances the detergency of mud stains more efficiently. To develop the composition, a new correction method based on the probability density functional method was used to compare the results of approximately 100 cleaning tests conducted on different days using various active ingredients. As a result of various evaluations, it was found that the combination of a homopolymer with a molecular weight of approximately 2000 and a chelating agent can effectively improve the detergency of particle stains. By combining washing experiments with different polymer concentrations, water hardness, turbidity, and reduced viscosity, we were able to estimate the expansion of the polymer and the washing mechanism using a combination of low-molecular-weight polymers and chelating agents.

Effect of Water Hardness on Acute Aquatic Toxicity of Fatty Acid Salts.

The acute aquatic toxicity of anionic surfactants, including fatty acid salts, changes depending on water hardness. Generally, the acute aquatic toxicity of Daphnia magna is caused by the adsorption of surfactants and other substances. Despite the low environmental risk, the effect of water hardness on the acute aquatic toxicity of soap should be discussed to improve the assessment accuracy. Previously, we evaluated the effects of water hardness and the presence of an adsorbent on the acute aquatic toxicity of soap by performing an immobility test using D. magna in accordance with Japanese Industrial Standards (JIS) K 0229. Immobility was low at 50 ppm and a higher water hardness was indicated owing to the loss of interfacial activities caused by the formation of insoluble fatty acid calcium or magnesium complexes (soap scum). In the current study, we evaluate the effects of water hardness on the acute aquatic toxicity of C10, C12, C14, C16, and C18 saturated and C18:1 unsaturated fatty acid sodium salts. The EC50 is measured via an immobility test in accordance with JIS K 0229 using D. magna, and the surface tension is measured as an indicator of surface activity. Results show that the EC50 and surface tension curves change with water hardness in single and mixed solutions. C18:1 indicates the least change and the highest surface activity. Moreover, immobility change is not observed when C18:1 is filtered, whereas the immobility of other solutions decreased significantly. This implies the effect of soap scum on immobility, such as the clogging of gills by soap scum. Based on quantitative analysis, the percentage of C18:1 that transformed soap scum to its initial concentration exceeds 80%. This implies that calcium deficiency under 5 and 25 ppm water hardness affects the immobility of larval D. magna. The effects of soap scum clogging and calcium deficiency on D. magna should be considered before assessing the soap.

Ultrasonic Cleaning for Irrigating Purulent Substances during Laparoscopic Gastrointestinal Surgery.

To improve the outcome of laparoscopic gastrointestinal surgery, improvement in the technology for removing purulent substances from the abdominal cavity is required. Ultrasonic cleaning technology may be suitable for the task. However, it is necessary to examine cleaning efficiency and safety through model tests that can lead to clinical trials for practical use. Nine surgical specialists first estimated the distribution of the actual attachment of purulent substances using videos of removing pus-like model dirt as an evaluation scale. Subsequently, cleaning tests were conducted using a small-size shower with model dirt that was somewhat difficult to remove, and its suitability as a model sample was confirmed. A mixture of miso and other substances was attached to a silicon sheet to prepare a test sample. The model dirt could be removed within a few seconds by cleaning using a probe-type ultrasonic homogenizer while the test sample was submerged in water. This performance greatly surpassed that of water flow cleaning under increased water pressure. An ultrasonic cleaner that is useful for irrigation during laparoscopic surgery will be suitable for practical use in laparoscopic surgery.

A Small-scale Washing Test That Reproduces the Mechanical Forces Occurring Inside a Commercial Washing Machine.

A small-scale washing test model was proposed to reproduce the mechanical forces occurring inside a household washing machine in Japan. Washing tests were conducted using household washing machines, a tergotometer, and four types of small-scale washing test models using JIS-designated artificially soiled fabric. As a result of conducting washing tests in 10 households during winter and summer, we determined that the mechanical force of the washing machine was equivalent to 90-100 rpm agitation by a tergotometer. Similar detergency was obtained by rotating a 50 mL centrifuge tube with a tube rotator. Then, a centrifuge tube containing 35 mL of detergent solution, ten 1/4-inch stainless steel balls, and three 20 × 20 mm soiled fabrics was rotated at 50 rpm. Probability density functional theory analysis did not identify any kinetic problems, which means that the properties of the applied mechanical forces are similar to those occurring in the tergotometer and tube rotator test.

Classification of the Biodegradation Factors of Linear Alkylbenzene Sulfonate.

The conditions that significantly affect the biodegradability of linear alkylbenzene sulfonate (LAS) based on previous studies were categorized. Among these previous studies, we focused on those that used activated sludge and river water as inocula in biodegradation studies. Analyzing the results of these studies revealed two types of methylene blue active substances (MBAS) removal curves in primary biodegradation, and the study conditions that differentiated the two types were analyzed, along with verification studies. The effects of the LAS concentration and interfacial activity during biodegradation were analyzed to set the concentration of LAS in this study. Surface tension was measured as an indicator of interfacial activity and biodegradation was measured by oxygen demand. Two widely used surfactants, alcohol ethoxylate and sodium dodecyl sulfate, were evaluated to clarify the significance of the effective concentration range of LAS. The concentration of LAS was set at 10 or 20 mg/L in the verification study. Acclimatization and the concentration balance of LAS and river water were the strongest factors in studies using activated sludge and river water, respectively. Our classification chart may be helpful in analyzing and comparing the conditions of previous and current studies. Such understanding of the study conditions and practical evaluation may aid in avoiding misleading environmental impact assessments of LAS.

Combined Use of Reducing Agents and Biodegradable Chelating Agent for Iron Rust Removal.

Since many of the current chemicals used to remove iron rust are hazardous to the environment and human health, the combined use of a reducing agent and a biodegradable chelating agent has been suggested as an environmental friendly and highly safe alternative. In the present work, the compatibility of the newly devised cleaning test with a model iron rust stain was confirmed by X-ray diffraction and scanning electron microscopy. Additionally, the cleaning efficiency of the method was evaluated by X-ray fluorescence. The cleaning mechanism and the synergistic effect of the reducing agent and the chelating agent was investigated using the phenanthroline absorption measurement method, and the results revealed that the reduced iron ions were dissolved by the chelating agent. The cleaning test proved that tetrasodium 3-hydroxy-2,2'-iminodisuccinate (HIDS) is a promising biodegradable chelating agent as an alternative to ethylenediaminetetraacetic acid (EDTA) for removing iron rust. It was also confirmed that the type of reducing agent used determines the pH at which detergency is enhanced. The detergency of the combination of the reducing agent and the biodegradable chelating agent was equal to or higher than the detergency of the acid agent, and thus, it was concluded that the proposed method has a great potential for commercial use.

Synergistic Action of Temperature and pH Factors in the Cleaning of Fatty Acids Soils; Analyzed by Probability Density Functional Method.

In this study, the interaction between the temperature and the pH of soil containing fatty acids with sodium dodecyl sulfate (SDS) aqueous solution was investigated to elucidate their synergistic effect in cleaning. A tergotometer was used for the cleaning test, and the cleaning results were analyzed by the probability density functional method, using the calculated parameter, µ rl , as an index of the cleaning power. The increase in µ rl by one of the factors was defined as ΔX or ΔY and the increase in µ rl by the both factors was defined as Δ(X + Y). It is assumed that there is a synergistic effect when Δ(X + Y) > ΔX + ΔY. The cleaning of fatty acid stains followed the addition rule pertaining to mechanical force and the pH effect. However, synergy was observed between the temperature and the pH effect. This was also supported by the plot of µ rl vs 1/T and observations using a phase-contrast microscope.

Kinetic analysis of hemoglobin detergency by probability density functional method.

In this study, washing tests were performed using samples prepared by contaminating fabrics with hemoglobin, and a kinetic analysis was conducted based the probability density functional method, which expresses the cleaning power using two parameters σrl (related to the cleaning mechanism) and µrl (related to the level of cleaning power). This method allows for the processing of uncertainties specific to protein washing under the assumption that the soil adhesion and detergency are in accordance with a normal distribution. A certain amount of hemoglobin solution was soaked in a cloth, dried, and steam-treated, and then used as a sample for a cleaning test. Two parameters σrl and µrl were calculated based on the detergency (%) after 5 min, 10 min, 15 min, and 20 min of washing with respect to different pH and temperature levels, and different sodium dodecyl sulfate (SDS) concentration and temperature levels. Based on the results, the value of σrl indicated that the hemoglobin was removed by the dissolving action. In addition, µrl increased in accordance with an increase in the pH, SDS concentration, and temperature. With respect to µrl, the relationship of ΔX + ΔY = Δ(X+Y) was observed in several cases, where ΔX represents the effect of the pH or SDS concentration, ΔY is the temperature effect, and Δ(X+Y) is the combined effect. Therefore, there may be an additive relationship between the pH and temperature effects, and the SDS concentration and temperature effects.

Effect of Awareness and Habits of Oral Care on Life Satisfaction.

PURPOSE: New methods of public education in oral care must be developed, because the public understanding of the importance of oral care is insufficient. This questionnaire study examined the parameters 'awareness and attitude relevant to teeth and mouth' and 'consciousness and attitude of daily life' in order to clarify what kind of information is needed for public education in oral care. MATERIALS AND METHODS: Data gathered in a survey of oral care behaviours and lifestyle among the elderly were analysed for oral care awareness and health of the teeth using the factor analysis method. The respondents were divided into four groups according to two factors relating to oral health condition and oral care awareness. RESULTS: The high oral-care-consciousness group had a greater awareness of general health and sociability as well as life satisfaction than did the low oral-care-consciousness group. However, the respondents' economic situation had a larger effect on life satisfaction. The respondents were then divided into higher, middle, and lower economic status groups, and the relation between oral care awareness and life satisfaction was analysed for each group. As a result, the correlation between life satisfaction and oral care consciousness was observed by excluding the economic factors. CONCLUSION: The present data suggest that oral care awareness may contribute to improvement of lifestyle and life satisfaction.

Analysis of Cleaning Process for Several Kinds of Soil by Probability Density Functional Method.

A method of analyzing the detergency of various soils by assuming normal distributions for the soil adhesion and soil removal forces was developed by considering the relationship between the soil type and the distribution profile of the soil removal force. The effect of the agitation speed on the soil removal was also analyzed by this method. Washing test samples were prepared by soiling fabrics with individual soils such as particulate soils, oily dyes, and water-soluble dyes. Washing tests were conducted using a Terg-O-Tometer and four repetitive washing cycles of 5 min each. The transition of the removal efficiencies was recorded in order to calculate the mean value (µrl) and the standard deviation (σrl) of the removal strength distribution. The level of detergency and the temporal alteration in the detergency can be represented by µrl and σrl, respectively. A smaller σrl indicates a smaller increase in the detergency with time, which also indicates the existence of a certain amount of soil with a strong adhesion force. As a general trend, the values of σrl were the greatest for the oily soils, followed by those of the water-soluble soils and particulate soils in succession. The relationship between the soil removal processes and the soil adhesion force was expressed on the basis of the transition of the distribution of residual soil. Evaluation of the effects of the agitation speed on µrl and Æ¡rl showed that σrl was not affected by the agitation speed; the value of µrl for solid soil and oily soil increased with increasing agitation, and the µrl of water-soluble soil was not specifically affected by the agitation speed. It can be assumed that the parameter Æ¡rl is related to the characteristics of the soil and the adhesion condition, and can be applied to estimating the soil removal mechanism.

Derivation of quantitative removal efficiency of protein stain from K/S value of washing test fabric soiled with hemoglobin.

We have improved a previous method for the preparation of hemoglobin-soiled fabrics in order to facilitate quantitative calculation of the efficiency with which protein stains can be removed from such materials. We then evaluated the sensitivity of surface reflectance as a method for stain quantification. Test fabrics were made by spotting a white fabric with a certain amount of hemoglobin solution and drying it. We observed a large difference between the percentage stain removal as measured by surface reflectance when compared with chemical analysis. Deformities in the surface of the soiled fabric caused by capillary action in the drying process likely contributed to this difference. Quantitative removal percentage could be predicted easily from the K/S values of test fabrics that were dry-heated without steam, although soil adhesion was too weak to evaluate the washing power of commercial detergent. Overall, we found that practical test fabrics with adequate soil adhesion properties can be prepared by adopting a steam heating process after dry heating.

Quantitative determination of colored oily soil adhering to metal surface using digital image data.

A method for calculating the amount of colored soil on a flat metal surface from digital image data was examined. Round samples cut out of SUS tape were soiled with oily soil mixed with sudan III, placed in sample bottles, and washed using a tube rotator. Images of the samples before and after the washing process were captured using a CCD camera and the image data were processed by a computer. The shine from the metallic surface was controlled by using indirect lighting. It was necessary to diminish the effect of the substrate's color, and to this end, we attempted to apply linear and non-linear color correction procedures. We found that the use of gamma correction after linear correction to remove the effect of the metal surface color was the most accurate quantitative method. Additionally, we conducted a washing test with commercial detergents using this quantitative method for image data and found that the removal process for the greasy soil from the metal surface could be expressed as a first-order reaction.

Effects of surface activity on aquatic toxicity of binary surfactant mixtures.

The purpose of this study was to discuss the effects of surface activity on the aquatic toxicity of binary surfactant mixtures comprising anionic, nonionic, and cationic surfactants. Surface tension was measured to determine the cmc (critical micelle concentration), and acute aquatic toxicity tests were conducted on Daphnia magna to obtain 24h-EC(50) (24h 50% effective concentration). TU (toxic unit) was calculated to evaluate the toxicity of the mixture. Most of the surfactant mixtures showed no synergistic increase in the aquatic toxicity. The mixture of anionic/nonionic surfactants showed synergistic interfacial activity with decreasing cmc, but the toxicity did not increase. The surface tension of the mixture at 24h-EC(50) (γ(tox)), which was used as an indicator of the toxic concentration, decreased considerably and TU was >1, indicating decreased toxicity. γ(tox) of the anionic/anionic surfactant mixture decreased when tested with hard water (hardness of 625 ppm). γ(tox) could not be used as a toxic indicator for the anionic/cationic surfactant mixtures because they showed aquatic toxicity before their surface tension began to decrease.

Decreases in surface activities and aquatic toxicities of linear alkylbenzene sulfonate and alcohol ethoxylates during biodegradation.

We discussed the relation between aquatic toxicity and interfacial activity during biodegradation with using LAS (Linear Alkylbenzene Sulphonate) and AE (Alcohol Ethoxylate). The change of death rate of Daphnia magna, surface tension, concentration of surfactant, and biodegradation by oxygen demand during biodegradation were measured. As a result, a rapid decrease in toxicity and rapid increase in surface tension were observed within the time before biodegradation based on oxygen demand started to increase. These rapid changes in toxicity and surface tension occurred due to the structural change of surfactant molecules in the primary biodegradation process, which was confirmed by HPLC (High Performance Liquid Chromatography) analysis. We also performed re-addition test to study the effects of acclimatization since it takes an important role on boidegradation, and found that the acclimatization significantly accelerated the primary biodegradation, which were indicated by increase in surface tension and decrease in aquatic toxicity. These results show that the environmental risk of surfactants should be considered not only with the biodegradation based on oxygen demand but also with the decrease of interfacial activity through the primary biodegradation process.

Application of statistical analysis to mixed soil detergency.

In previous studies, statistical method using distribution of detergent power and that of resistance of soil against washing was applied to analyze detergency of oily soil and solid particle soil. In this paper, this method was applied to an analysis of detergency of mixed soil. Artificially soiled cloth prepared by aqueous dispersion method was used as a mixed soil sample. Four-time consecutive washing tests were conducted under the same washing condition in Terg-O-Tometer using two kinds of detergent solution and distilled water. Change of removal efficiencies due to repetitive washing was used to determine the two distributions. Result shows that detergent power can be expressed as cumulative distribution function. In washing simulation using the cumulative distribution functions, the predicted removal efficiencies corresponded with experimental values. Moreover, the effect of soil aging on distribution of soil resistance against washing was found to move the distribution curve toward high resistance. These results show that the method using two statistical distributions can be applied to the detergency of mixed soil.

Large decrease in acute aquatic toxicity of linear alkylbenzene sulfonate in hard water and seawater by adding adsorbent.

LAS (Linear Alkylbenzene Sulphonate) shows relatively high aquatic toxicity in hard freshwater or seawater. In this paper, we studied the effect of adsorbent on the aquatic toxicity of LAS in hard freshwater and seawater. Daphnia magna and Artemia salina were used for acute aquatic toxicity test in freshwater and seawater, respectively. Kaolin was used as a model adsorbent and toxic surface tension (gamma(tox)) was used as an indicator of toxic condition. Results showed that the values of gamma(tox) of LAS to D. magna and A. salina were about 45-55 mN/m and 35-40 mN/m, respectively. Surface tension of LAS solution decreased and its aquatic toxicity increased with increasing the water hardness or the salinity. By adding adsorbent into the solutions, the surface activity and the aquatic toxicity were decreased greatly, and the effect of water hardness or salinity on surface tension and aquatic toxicity were removed. That is to say, the surface tension curve of soft freshwater corresponds with that of hard freshwater containing adsorbent and the surface tension curve at low salinity corresponds with that obtained for high salinity solutions containing the adsorbent. Therefore, our experimental data leads to the conclusion that the relatively high aquatic toxicity of LAS in concentrated solution of inorganic salts disappears in the presence of adsorbents. This is an important viewpoint in conducting environmental risk assessment of surfactants.

Statistical analysis of washing efficiency for solid particle soil.

In a previous study, statistical method using two distributions was applied to analyze detergency of oily soil. The method uses statistical distributions of detergent power and adhesive force of soil. In this paper, this method was applied to an analysis of detergency of solid particles. Soiled cotton cloth was prepared with red iron oxide dispersion liquid in Terg-O-Tometer. Four-time consecutive washings tests were conducted with dodecyl sulfuric acid sodium salt (SDS) and alcohol ethoxylate (AE) aqueous solutions in Terg-O-Tometer. Change of removal efficiencies due to repetitive washing was utilized to seek the two distributions. Predicted removal efficiencies calculated from computer simulation corresponded to experimental values. Different adhered states of soil, prepared by varying soiling conditions, were expressed as Removal Resistance. As soiling mechanical power increased, Removal Resistance shifted toward higher adhesive force of soil and an amount of soil had also increased. Iron oxide concentration only had an affect on an amount of soil. The results showed that the method using two statistical distributions can be applied to the detergency of solid particle.

Effects of water hardness and existence of adsorbent on toxic surface tension of surfactants for aquatic species.

We have studied the effectiveness of surface tension on surfactants risk assessment. gamma(tox) was defined as surface tension at a point where acute aquatic toxicity of a surfactant emerges. Oryzias latipes, Daphnia magna, and Podocopida were used for acute aquatic toxicity test of 7 surfactants and 3 detergents. Gamma(tox)values were plotted on surface tension curves, and the effect of water hardness on toxicity and surface tension were examined. Results showed that gamma(tox) varies greatly by kind of surfactant or detergent. Therefore, aquatic toxicity cannot only be explained by surface tension. The change of aquatic toxicity with varying water hardness, however, could be explained by the change of surface tension. Aquatic toxicity of LAS (Linear Alkylbenzene Sulphonate) increased and aquatic toxicity of SOAP decreased with an increase of water hardness, but both gamma(tox), values were constant. Aquatic toxicity was decreased by an addition of mud soil as adsorbent into surfactant solution. The toxicity change can be explained by the surface tension since gamma(tox) value of solution with and without mud soil were equal. These results showed that the change of aquatic toxicity of a surfactant caused by water property, such as water hardness, could be explained by the change of surface tension.