Antifoam Research Articles

Simethicone use in drug-induced sleep endoscopy improves visibility.

To assess the effect of simethicone, a defoaming agent, on improving visibility during drug-induced sleep endoscopy (DISE) in obstructive sleep apnea (OSA). The study was a retrospective case-series study on patients with OSA who failed positive airway pressure (PAP) treatment. Patient parameters were recorded including age, BMI, neck and abdominal circumference, and apnea-hypopnea index (AHI). Comparisons were made between DISE procedures performed with and without the administration of simethicone. Visibility during DISE was independently graded by two surgeons, and inter-rater reliability was assessed. Simethicone significantly improved DISE visibility (p = 0.03). "Best visibility" was achieved in 55% of cases with simethicone compared to 27% without simethicone (p = 0.02). Sub-analysis showed that only simethicone administration had a significant effect on visibility (p = 0.02). Inter-rater reliability between the grading surgeons was strong (Cohen-Kappa score 0.7, p < 0.001). The findings suggest that simethicone enhances DISE visibility for OSA surgical planning. Further research should explore optimizing simethicone administration timing and the potential clinical implications for surgical outcomes and patient care.

Control of plant-based biopolymer composite gel texture: Combining potato proteins with different high acyl-low acyl gellan gum ratios

The impact of blending different kinds of gellan gum (GG) on the textural attributes of potato protein-based biopolymer composites was studied. The total potato protein concentration (10 wt%) and gellan gum concentration (3 wt%) of the composite gels was fixed but the ratio of HAGG (forms soft and elastic gel) to LAGG (forms hard and brittle gel) was varied (100:0 to 0:100). During cooling, HAGG set at a higher temperature than LAGG, due to differences in steric hindrance effects. As the LAGG content increased, the shear modulus, Young's modulus, and brittleness of the gels increased, while their water holding capacity decreased. There were no major differences in the nature of the molecular interactions between the proteins in composite gels formulated using different gellan gum ratios. The addition of an antifoaming agent significantly reduced the variability in the textural attributes of the gels and increased their gel strength, which was attributed to its ability to suppress bubble formation. Overall, our results suggest that the textural attributes of biopolymer composite gels can be controlled by using plant proteins in combination with a pair of polysaccharides with different gelling properties. This knowledge may aid in the formulation of soft solid plant-based foods with more desirable textural attributes, such as meat, seafood, or egg analogs.

The role of video capsule endoscopy in the diagnosis of gastrointestinal diseases: experience of the Department of Diagnostic and Operative Endoscopy

Introduction. Video capsule endoscopy (VSE) is a gold standard diagnostic method for small bowel diseases and is widely used in clinical practice. The presented analysis of the VCE results demonstrates the possibilities of this diagnostic tool and is the largest one of the analysis that were recently published in Russia. Aim. To demonstrate the possibilities of video capsule endoscopy in the diagnosis of small bowel diseases. Materials and methods. A total of 300 video capsule endoscopies were performed in patients with suspected and already established small bowel diseases between 2014 and 2022. All patients who underwent a video capsule endoscopy in the settings of the National Medical Research Center of Coloproctology named after A.N. Ryzhikh were over 18 years old. The study cohort included 158 men and 142 women. The average age of patients at the time of the video capsule endoscopy was 42 ± 15.4 years. The patients were recommended a standard preparation regimen: 3 days before the study, a protein diet was prescribed, and the day before, a two-stage administration of a PEGbased drug (“split dose”). To reduce gas production and decrease the amount of foamy intestinal contents, which worsens the quality of the endoscopic image, oral administration of an antifoam agent simethicone was prescribed: 80 mg on the eve of the endoscopy and 80 mg on the day of the endoscopy. Results. The video capsule endoscopy demonstrated high information value in the diagnosis of inflammatory bowel diseases: its sensitivity was 86%, and specificity – 90%. Similar results were obtained during video capsule endoscopy used to diagnose the source of possible bleeding: sensitivity and specificity were 87 and 68%, respectively. Conclusion. Video capsule endoscopy is an effective, safe and well-tolerated tool for diagnosing small bowel diseases. The video capsule endoscopy findings contribute to establishing a correct diagnosis and selecting treatment strategies.

Physical Factors Affecting the Scale-Up of Vegetative Insecticidal Protein (Vip3A) Production by Bacillus thuringiensis Bt294

Vip3A (vegetative insecticidal protein) is a representative member of the Vip3 family, which is widely used for lepidopteran pest control. This Vip3A protein, a non-growth-associated protein, is an effective bioinsecticide against insect pests, but there is relatively little information about its production processes at large scales. Hence, the effects of environmental factors on Vip3A production by Bacillus thuringiensis Bt294 (antifoam agents, shaking speeds, agitation and aeration rates), as well as controlling physical conditions such as the lowest point of dissolved oxygen and controlling of culture pH, were observed in shaking flasks and bioreactors. The results showed that antifoam agents, flask types and shaking speeds had significant effects on Vip3A and biomass production. Cultivation without pH control and DO control in 5 L bioreactors at lower agitation and aeration rates, which was not favorable for biomass production, resulted in a high Vip3A protein production of 5645.67 mg/L. The scale-up studies of the Vip3A protein production in a pilot-scale 750 L bioreactor gave 3750.0 mg/L. Therefore, this study demonstrated the significant effects of agitation, aeration rates and culture pH on Vip3A production by B. thuringiensis Bt294. Balancing of physical conditions was necessary for obtaining the highest yield of Vip3A by slowing down the production rate of biomass. Moreover, this Vip3A protein has high potential as a bioinsecticide for lepidopteran pest control in organic crops. This information will be important for significantly increasing the Vip3A protein concentration by the bacterium and will be useful for field application at a lower cost.

Investigation on basic properties and microscopic mechanisms of polyacrylate latex modified cement grouting material for water blocking and reinforcement

Grouting is a highly effective engineering intervention utilized to address water inrush disasters and reinforce weak surrounding rock formations, with the grouting material playing a crucial role in determining the outcomes of grouting operations. To simultaneously meet the requirements of water plugging and reinforcement, a new polyacrylate latex modified cement grout was prepared, consisting of superfine cement, polyacrylate latex, a defoaming agent, and a coagulation accelerator. This study reports on a series of tests conducted to examine the workability, mechanical properties, and microstructures of polyacrylate latex modified cement grout with varying ratios. The experimental results indicate that the addition of polyacrylate latex significantly reduces the bleeding ratio of the grout, as well as improves its groutability and enhances its resistance to dynamic water scouring, particularly under high-flow conditions. The viscosity of the composite grout increases by adding polyacrylate, leading to a decrease in its fluidity. As the proportion of polyacrylate latex increases, the early and final strength of the grout stone body increases while the porosity decreases. The hydration degree of the grout shows a growing trend with the addition of polyacrylate latex based on the observations by low-field nuclear magnetic resonance tests. The modified grout stone body is dense, primarily due to the chemical reaction between calcium ions produced by cement hydration and carboxyl groups produced by the hydrolysis of ester groups on the polyacrylate latex, leading to cross-linking between the inorganic and organic phases and the formation of a complex network structure. Excellent working performance particularly in terms of anti-scour and load-bearing capacity makes polyacrylate modified cement grouting materials highly suitable for use in the simultaneous treatment of water inrush and reinforcement.

Behaviors of Bubbles Trapped in Film Coating during Spray Gun Coating and Its Influences on Coating Defects

In this paper, we investigated the behaviors of bubbles entrained in a film coating during spray coating. Air bubbles that remain in a film coating after diluent evaporation cause coating defects called bubbling defects, including fish-eye and crater defects. In this study, the visualization of a film coating revealed that smaller bubbles in the film shrank slowly and disappeared, while larger bubbles remained. These remaining bubbles grew during the heating process for the drying of the film coating. The shrinking phenomenon was explained using bubble dynamics based on the Young–Laplace equation of a bubble’s inner pressure and Henry’s law for bubble gas dissolution into the film coating. This shrinking model is often used in studies on microbubble dynamics. The results suggested the importance of avoiding the entrainment of large bubbles during the spraying process and enhancing the release of air bubbles from the film coating’s surface through the appropriate usage of defoaming agents.

Biopolymeric conjugation with food additives

Abstract In the contemporary day and age, the usage of food additives has predominantly expanded because of accelerated processed food’s requirement. Food additives comprises of preservatives, color dye, flavors, textural additives, antimicrobial agents, antioxidants, anti-caking additives, anti-foaming agents, emulsifiers and nutritional additives. Although, food additives assist in proving textural benefits, increased shelf life, color addition and flavor enhancer but limitations are also associated with the use of food additives such as reduction in shelf life, toxic behavior, reduced stability and controlled target release issues. Biopolymers, dominantly pervasive macromolecules are the prominent class of utilitarian materials which are convenient for valuable applications. Across the globe, professionals and researchers are highly interested in research on biopolymers due to its biocompatible and biodegradable prospect. The two major classifications of biopolymers include proteins and polysaccharides. Different types of biopolymers can also work as fat replacer and therefore offer prevention from coronary disease, obesity as well as diabetes. Food industry has been highly promoted and benefited from the use of biopolymers. The employment of biopolymers solves the issues related to food additives consumption. Therefore, this particular chapter elucidates about the biopolymeric conjugation with food additives for a perfect food design, importance of biopolymers and application of biopolymers in association with food additives.

Failure analysis and quick recovery of a low‐temperature distillation station

AbstractA coupling model based on hazard and operability analysis (HAZOP) and fault tree analysis is proposed and used to analyze the failure of a low‐temperature distillation station (LTDS). It is found that the formation of scale in the deamination tower in the LTDS is the most significant cause for the failure. The scale was mainly composed of SrSO4, CaCO₃, CaSO4, and MgCO₃, which were determined by various techniques from the gas‐field water. Dynamic weight loss experiments were conducted to estimate the corrosion rate of 304 steel with different cleaning solutions. The corrosion behaviors of the metal in the deamination tower were further investigated in three types of cleaning solution via potentiodynamic polarization method. The cleaning solution composed of 6% sulfamic acid, LAN826, JFC, and a defoaming agent could safely and quickly remove the scale covering the LTDS at 50°C. In addition, the optimal cleaning time was found to be 6 h.

Comparative Evaluation of Viscosity, Density and Ultrasonic Velocity Using Deviation Modelling for Ethyl-Alcohol Based Binary Mixtures

This study reports the comparative deviations in experimental viscosity, density and ultrasonic velocity of two new ethanol-based binary liquid mixtures (ethanol + 1-hexanol and ethanol + 1-octanol) at 303.15 K by applying various theoretical models (Hind relation (ηH), Kendall and Monroe relation (ηK-M), Bingham relation (ηB), Arrhenius–Eyring relation (ηAE), Croenauer-Rothfus Kermore relation (ηCRK) and Gambrill relation (ηG)). Typically, the experimental densities are compared with theoretical methods like the Mchaweh–Nasrifar–Mashfeghian model (ρMNM), Hankinson and Thomson model (ρHT), Yamada and Gunn model (ρYG) and Reid et al. (ρR) model. Additionally, the experimental ultrasonic velocities are compared with various theoretical models like the Nomoto relation (UN), Van Dael and Vangeel relation (UIMR), Impedance relation (UIR), Rao’s specific velocity relation (UR) and Junjie relation (UJ). The average percentage of deviation (APD) is determined to identify the most suited model that can closely agree to the experimental values of the specified property (viscosity, density and ultrasonic velocity). From the APD values, it may be concluded that the ηK-M model is the most suitable theoretical method for estimating the viscosity for the ethanol + 1-hexanol system, and the Gambrill model is the suitable method for estimating viscosity for ethanol + 1-octanol liquid systems. Similarly, the model of Reid et al. and Jungie’s relation are the most suited theoretical models to predict the density and ultrasonic velocity of the binary liquid systems, respectively. Form the experimental data, various molecular interaction properties like adiabatic compressibility, intermolecular free length, free volume, internal pressure, and viscous relaxation time are analysed. The results of this study are expected to be useful in predicting the suitable molecular proportions that can be suited for industrial application (flavouring additive, insecticide, in the manufacture of antiseptics, perfumes for 1-hexanol based mixtures and flavouring, and as an antifoaming agent for 1-octanol based liquid mixtures).

Fabrication of low defect multi-layer graphene using electrochemical intercalation of graphite electrode and its application for graphene/Al nanocomposites

Low defect multi-layer graphene has been synthesized by electrochemical intercalation of graphite electrode in ammonium sulfate aqueous solution, followed by microwave heating and subsequent ultrasonication. Combination of addition of ethanol as antifoaming agent, alternating current and end-face electrolysis was very effective for high yield production (>75%) of low defect graphene. We applied as-synthesized graphene for graphene/Al composites using stir casting method. Graphene/Al composites with a graphene loading of 0.3% have approximately 40% higher tensile strength (142.2 MPa) and much lower coefficient of thermal expansion (19.8 × 10-6/K) as compared with pure Al (104.0 MPa, 22.7 × 10-6/K).

The practical management of chronic constipation as detected by a survey conducted on Italian gastroenterologists

BACKGROUND: Chronic constipation represents a widespread medical condition, mainly in elderly people. The management is compelling as these patients frequently have comorbidity and polypharmacy. Polyethylene glycol (PEG) is commonly used but does not resolve some complaints, mainly concerning pain and bloating. Therefore, a new medical device containing PEG plus simethicone, an antifoaming agent, has been developed. The present survey explored its use in clinical practice.METHODS: A group of 64 Italian gastroenterologists visited 2426 patients with chronic primary constipation. In about two/third, gastroenterologists freely prescribed the new medical device, and in the remaining patients, other treatments were freely chosen by doctors. Patients were followed up for three months. The number of evacuations, stool characteristics, patients’ perception of illness assessed by VAS, frequency of patients with pain and intestinal symptoms, and discontinuing patients was observed during the experience.RESULTS: The new medical device was significantly better than other therapies in improving all parameters (P<0.05 for all parameters).CONCLUSIONS: The present survey demonstrated that a new medical device containing PEG plus simethicone represents a favorable option in managing patients with chronic primary constipation as significantly and safely improves intestinal transit, reduces stool consistency, reduces symptom severity, and is highly satisfactory.

A water-soluble alternative to simethicone for gastrointestinal endoscopy: Results of a clinical trial

During endoscopy, simethicone defoaming agents are commonly used to improve visualization, but they leave residues and impact drying. This clinical trial involved patients undergoing colonoscopy procedures with substantial bubbles that impeded mucosal wall visibility. As an alternative to simethicone, investigators evaluated a water-soluble, ginger-based gastrointestinal supplement (GI-Ease) that did not contain sugars, thickeners, or binding agents. In 112/114 cases (98%), the bubbles were reduced sufficiently to allow visualization of the gastrointestinal tract, with no adverse events.

Antifoaming Agent for Lubricating Oil: Preparation, Mechanism and Application

In the process of using lubricating oil, it is inevitable that bubbles will be produced, which can not only accelerate the oil's oxidation and shorten the oil change cycle but also reduce its fluidity and lubricity, aggravate the wear of mechanical parts and produce an air lock that interrupts the oil pump supply and causes an oil shortage accident. This paper mainly and comprehensively discusses the foaming process and its harm, the defoaming mechanism and defoaming method of lubricating oil, more specifically, the synthesis, application, advantages, disadvantages and current situation of three kinds of chemical defoaming agents, namely silicone defoaming agent, non-silicone defoaming agent and compound defoaming agent. Finally, the paper looks forward to the future development of special defoaming agents for lubricating oil.

Effect of defoaming agent on the properties of cement mortars with hydroxyethyl methyl cellulose through adjusting air content gradient

Pore structure plays one of the most important role in the properties of cement-based materials. Hydroxyethyl methyl cellulose (HEMC) has the air entrainment effect, which may significantly change the pore structure and further affect the performance of this materials. Incorporating defoaming agent (DA) may weaken this effect, due to its defoaming effect which needs to be fully evaluated. Therefore, the working efficiency of DA and the changes of pore structure caused by stepwise adjustment of the air content were mainly studied. The results show that incorporating DA can effectively eliminate air bubbles, while the defoaming effect is weak with the air content approaching to 6.0%. There is a certain negative correlation between fresh bulk density and air content, and a positive correlation between fluidity and air content. Incorporating an appropriate dosage of DA is beneficial to control the air content of the cement mortars with HEMC, so as to ensure the cement mortars have better mechanical strengths and low drying shrinkages. With the increase of DA dosage, the large capillary pores, macro pores and total porosity all show a gradual decreasing trend due to the air content decreasing. The content of connected capillary pores in cement mortars tends to increase as the air content level decreases, but shows a small decrease at the low air content of less than 6.0%.

Improvement of Nitrite Analysis Method in Food Products

The conventional analysis method has problems with extraction efficiency, operability, and reproducibility. In this study, we attempted to solve these problems and improve the analytical method to obtain sufficient extraction efficiency and good operability and accuracy. The conventional method was able to get sufficient extraction in dried meat products, where the extraction efficiency of the conventional method was low, by increasing the concentration of sodium hydroxide solution at the time of homogenization. Suction filtration after adding the defoaming agent was added allowed for accurate volume adjustment. The turbidity of the extract caused by insufficient addition of zinc acetate solution was removed by increasing the amount of zinc acetate solution that was added. Turbidity caused by starch was removed by adding pancreatin. The RSD of the quantitative values was improved by adding sodium hydroxide solution and 80-90℃ water and immediately homogenizing. Furthermore, by changing the dilution factor of the extract solution in the colorimetric method, the inhibition of coloration by reducing substances was suppressed, and more accurate quantitative values could be obtained than with the conventional method. The recovery rate was 78.5-105% (RSD 0.7-5.8%), which was a good result. This method was considered to be a useful analytical method that can contribute to improving the inspection accuracy of nitrite ion analysis.

Effects and mechanisms of foam suppression in food waste anaerobic digester using defoaming agents

The defoaming effects of organic silicone defoamer S-559 (OSD), polyether defoamer S-717 (PD), polyether-polysiloxane defoamer S-722 (PPD), high-carbon alcohol defoamer S-714 (HCD), corn oil (CO), and biochar derived from biogas residue (BBR) were investigated based on the foaming potential test, biotoxicity test, and long-term semi-continuous test. Foaming potential experiments showed that the OSD, PD, PPD, and CO had the best initial and continuous defoaming efficiency. However, PD was biotoxic. The cumulative methane production of food waste from the batch anaerobic digesters decreased by 18.4% and 22.6% after adding 0.1% (v/v) and 0.5% (v/v) PD, respectively. After the OSD was used several times in semi-continuous experiments, the foam reduction efficiency of the OSD increased to more than 98% and the foam recurrence efficiency of the reactor decreased to <21%. In contrast, the foam reduction efficiency of the CO decreased to<18% after long-term use, and the foam recurrence efficiency increased to more than 120%. The reason for the difference in defoaming performance is that the OSD was composed of solid hydrophobic particles with sharp edges, and the liquid phase had good spread ability and low surface tension. Thus, OSD relied on the bridging-stretching mechanism, the bridging-dewetting mechanism, and the spreading effect for defoaming. CO is a liquid defoamer with low surface tension, which may only rely on the bridging-stretching mechanism for defoaming. These results provide a reference for selecting a defoamer for a food waste anaerobic digestion system, and provide insight for the development of new defoamers.

The use of antifoam agents to eliminate bubbles during biotechnological sample analysis

Colorimetric protein quantitation assays such as the Bradford method are susceptible to foaming when using manual or automated equipment, especially during mixing operations. The resulting bubbles cause unintended light scattering and, because they often persist for longer than the duration of the assay, can interfere with spectrometric sample analysis, for example in a 96-well plate reader at 585 nm. Here, we tested the ability of antifoam agents commonly used in biotechnology to reduce bubble formation when mixing Bradford reagent with protein samples from bioprocess development and production. We also assessed the impact of these agents on optical density at the assay-relevant wavelength to verify the fidelity of the readouts. We used a design of experiments approach to identify synergies between different antifoam agents, aiming to reduce the concentration needed to avoid foam formation and thus minimize any distortion of the assay results. Finally, we confirmed that antifoam-containing Bradford reagent retained its performance even after prolonged storage. We found that 0.15 g L−1 of Struktol J673A was sufficient to prevent foaming even when air was deliberately introduced into the samples. Furthermore, the modified Bradford reagent was stable for 4 weeks and did not distort the readout at 585 nm but only shifted it by ~ 0.1 dimensionless absorbance units. Therefore, our modified Bradford reagent will benefit biologists, biotechnologists and bioprocess engineers, especially those using automated workstations, because it improves the robustness of the assay.

Enhanced fermentation of biosurfactant mannosylerythritol lipids on the pilot scale under efficient foam control with addition of soybean oil

Biosurfactant mannosylerythritol lipids (MELs) are green alternatives to chemically synthesized surfactants. However, these biosurfactants typically have a high cost-of-production limiting their adoption for industrial applications. In this study, an optimized fermentation process at pilot scale to furnish MELs with Pseudozyma aphidis DSM 70725 was developed. This involved the optimization of the levels of Fe2+, Fe3+ to improve the fermentation efficacy and the use of soybean oil to reduce the foam generated during fermentative production of MELs. The MELs titer, production rate and the conversion ratio of the carbon source was enhanced to 61 g/L, 0.255 g/L/h and 0.68 g/g, respectively. These optimizations resulted in approximately 100% improvement over regular fermentation processes and are amenable to the large-scale fermentation of MELs employing soybean oil as an antifoam agent to overcome foaming issues.

Development of a Low-pH Concrete Intended for Deep Geological Repository for Radioactive Waste

This article deals with the development of concretes intended to be used as construction materials in the Czech deep repository for radioactive waste. The basic requirements for this concrete are a reduced pH value, which must maintain a constant reduced pH with a value of around 11 in the long term, and mechanical properties comparable to conventional concrete. The raw materials for the production of the proposed low pH concrete come exclusively from the Czech Republic. Material characteristics were measured on fresh mixtures and concrete after 28, 56, and 90 days of curing. In addition to the basic raw materials (aggregate, cement, water), plasticizers, microsilica or slag, and defoaming agents were added to the mixture. The aggregate:binder ratio was approximately 5:1 and the w/c water coefficient was approximately 0.6. The mechanical properties of the final concrete were similar to the reference recipe of conventional concrete (the decrease was less than 10%) and the pH value was even below 11 after 90 days. The issue of a sprayed variant of the LPC mixture was solved within the project.

Assessment of foam generation and stabilization in the presence of crude oil using a microfluidics system

The use of foams is a promising technique to overcome gas mobility challenges in petroleum reservoirs. Foam reduces the gas mobility by increasing the gas apparent viscosity and reducing its relative permeability. A major challenge facing foam application in reservoirs is its long-term stability. Foam effectiveness and stability depends on several factors and will typically diminish over time due to degradation as well as the foam-rock-oil interactions. In this study, the effect of crude oil on CO2-foam stability and mobility will be investigated using in-house build microfluidics system developed for rapid prescreening of chemical formulations. Two-phase flow emulsification test (oil-surfactant solutions) and dynamic foam tests (in the absence and presence of crude oil) were conducted to perform a comparative assessment for different surfactant solutions. A microfluidics device was used to evaluate the foam strength in the presence and absence of crude oil. The assessment was conducted using five surfactant formulations and different oil fractions. The role of foam quality (volume of gas/total volume) on foam stability was also addressed in this study. The mobility reduction factor (MRF) for CO2-foam was measured in the absence and presence of crude oil using high salinity water and at elevated temperatures. The results indicated that foam stability has an inverse relationship with the amount of crude oil. Crude oil has a detrimental effect on foams, and foam stability decreased as the amount of crude oil was increased. Depending on the surfactant type, the existence of crude oil in porous media, even at very low concentrations of 5% can significantly impact the foam stability and strength. The oil can act as an antifoaming agent. It enters the thin aqueous film and destabilizes it. This resulted in a lower foam viscosity and less stable foams. Thus, the CO2 MRF dropped significantly in the presence of higher oil fractions. This study also demonstrated that in-house assembled microfluidics system allows for a rapid and cost-efficient screening of formulations.