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Earth pressure balance (EPB) shield is increasingly employed in metro tunnel construction, and causes a series of environmental, safety, and resource waste problems due to the disposal of a considerable amount of muck. In situ recycling of EPB shield muck is an effective solution, whereas the foam is generated by residual foaming agents used as the muck conditioning material during tunnelling, which often adsorbs clay particles and overflows the flocculation tank. To achieve defoaming and antifoaming during the reuse of muck, this study prepared novel eco-friendly silicone oil-polyether defoamers by condensation, compounding, and shear emulsification. Defoaming and antifoaming performances of different defoamers were tested using a modified Ross-Miles method and a scale model of field flocculation systems. The results indicated that a high efficiency in defoam and antifoam was characterized by chemical grafting of nano-SiO 2 from silicone oils, uniform distribution and large size of grains, low viscosity, and surface tension. The defoamer dosage of 0.002-0.004 wt% near critical micelle concentration (CMC) for each defoamer is reasonable. Overall, the prepared hydroxyl silicone oil-glycerol polyoxypropylene ether (H-G) defoamer compared with other silicone oil-polyether defoamers and commercial defoamers presents the highest defoaming and antifoaming efficiency. Considering the effects of EPB shield muck, the H-G defoamer is least affected by the compound materials and increasing concentration of the commercial foaming agent. Nevertheless, the stability of the H-G emulsion system is weaker than that of the dimethyl silicone oil-glycerol polyoxypropylene ether (D-G) emulsion system after 1 month of sealed storage., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background/aim: To assess the efficacy and safety of simethicone with or without N-acetylcysteine (NAC) as premedications before gastroscopy., Materials and Methods: We searched EMBASE, PubMed, Cochrane library and Web of Science database for randomized clinical controlled trials regarding simethicone ± NAC as oral drinking agents before gastroscopy. Statistical software RevMan5.3 was used for statistical analysis., Results: Ten randomized clinical trials that fulfilled the inclusion criteria were further pooled into a meta-analysis, which included 5,750 patients. The rate of positive findings in simethicone plus NAC group was higher than that in water group (risk ratio [RR] =1.31, 95%CI: 1.12-1.53, P = 0.0006) with high level of evidence. There was no significant difference on the rate of positive findings when comparing simethicone with simethicone plus NAC (RR = 1.02, 95%CI: 0.90-1.16, P = 0.71) and with water (RR = 1.13, 95%CI: 0.82-1.55, P = 0.46), respectively. Simethicone plus NAC showed better total mucosal visibility score than simethicone alone (MD = -0.14 (-0.25, -0.03), P = 0.01) without obvious heterogeneity. Both simethicone plus NAC and simethicone alone offer more benefit than water. The procedure time in simethicone group was shorter than that in water group (MD = -1.23 (-1.51, -0.96), P < 0.00001). Regarding adverse events, there was no significant difference in simethicone and water group (RR = 0.45, 95%CI: 0.2-1.0, P = 0.05, I 2 = 0%)., Conclusions: As premedication of gastroscopy, simethicone plus NAC offers more benefit on positive findings and total mucosal visibility score., Competing Interests: None

Introduction: Radiation therapy is a standard treatment option for prostate cancer. With growing use of escalated doses and tighter margins, procedures to limit rectal size variation are needed to reduce prostate motion, increase treatment accuracy, and minimize rectal toxicity. This prospective study was done to determine whether the introduction of an antiflatulent medication would decrease rectal distention at computed tomography (CT) simulation and throughout a course of radiation therapy., Methods and Materials: Patients undergoing a radical course of radiation therapy to the prostate/prostate bed were eligible to participate. Participants were randomly assigned to the intervention arm (antiflatulent medication) or the control arm (no medication). For each participant, the number of CT simulation rescans was recorded. Rectal diameters were measured on CT simulation and treatment cone beam CT scans. Acute rectal toxicities were assessed at baseline and weekly using National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), version 4.0. A χ 2 analysis was used to compare the number of participants requiring a rescan in each study arm. Change in rectal diameter over time was assessed using repeated measures analysis of variance., Results: A total of 78 patients participated, with equal numbers assigned to each study arm. There was no significant difference between arms in the number of participants requiring a CT simulation rescan (P = .5551). There was no significant variation in rectal diameter between arms (P = .8999); however, there was a significant effect of time (P = .0017) and a significant interaction effect between study arm and time on rectal diameter (P = .0141). No acute rectal toxicities above grade 2 were reported., Conclusions: The addition of antiflatulent medication did not affect the frequency of CT simulation rescans. Both time and the interaction between study arm and time had a statistically significant effect on rectal diameter, although neither finding was clinically significant. Instead, standardized bowel preparation education developed for this study may have been sufficient to limit rectal size variation., (Copyright © 2017 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)

Background and Aim: To investigate the efficacy and safety of premedication with simethicone/Pronase during esophagogastroduodenoscopy (EGD) with sedation., Methods: Six hundred and ten patients were randomly allocated to two groups based on type of premedication given. Premedication used in the control group was 10 mL lidocaine hydrochloride mucilage (LHM, N = 314) and premedication used in the intervention group was 80 mL simethicone/Pronase solution plus 10 mL lidocaine hydrochloride mucilage (SP/LHM, N = 296). EGD was done under sedation. Visibility scores, number of mucosal areas that needed cleansing, water consumption for cleansing, time taken for examination, diminutive lesions, pathological diagnosis, patients' gag reflex and oxygenation (pulse oximetry) were recorded., Results: SP/LHM has significantly lower total visibility score than LHM (7.978 ± 1.526 vs 6.348 ± 1.097, P < 0.01). During the procedure, number of intragastric areas that needed cleansing and amount of water consumed were significantly less in the SP/LHM than in the LHM group (P < 0.01). In SP/LHM (P = 0.01), endoscopy procedure duration was significantly longer. Although there was no significant difference in rate of detection of diminutive lesions between LHM and SP/LHM, the endoscopist carried out more biopsies in SP/LHM. This led to a higher rate of diagnosis of atrophic gastritis (P = 0.014) and intestinal metaplasia (P = 0.024). There was no significant difference in gag reflex (P = 0.604) and oxygenation during the endoscopy procedure for either group of patients., Conclusion: Routine use of premedication with simethicone/Pronase should be recommended during EGD with sedation., (© 2017 Japan Gastroenterological Endoscopy Society.)

The Brazilian sugarcane industry constitutes one of the biggest and most efficient ethanol production processes in the world. Brazilian ethanol production utilizes a unique process, which includes cell recycling, acid wash, and non-aseptic conditions. Process characteristics, such as extensive CO 2 generation, poor quality of raw materials, and frequent contaminations, all lead to excessive foam formation during fermentations, which is treated with antifoam agents (AFA). In this study, we have investigated the impact of industrial AFA treatments on the physiology and transcriptome of the industrial ethanol strain Saccharomyces cerevisiae CAT-1. The investigated AFA included industrially used AFA acquired from Brazilian ethanol plants and commercially available AFA commonly used in the fermentation literature. In batch fermentations, it was shown that industrial AFA compromised growth rates and glucose uptake rates, while commercial AFA had no effect in concentrations relevant for defoaming purposes. Industrial AFA were further tested in laboratory scale simulations of the Brazilian ethanol production process and proved to decrease cell viability compared to the control, and the effects were intensified with increasing AFA concentrations and exposure time. Transcriptome analysis showed that AFA treatments induced additional stress responses in yeast cells compared to the control, shown by an up-regulation of stress-specific genes and a down-regulation of lipid biosynthesis, especially ergosterol. By documenting the detrimental effects associated with chemical AFA, we highlight the importance of developing innocuous systems for foam control in industrial fermentation processes.

The effects of antifoaming agents on fermentative hydrogen production using galactose in batch and continuous operations were investigated. Batch hydrogen production assays with LS-303 (dimethylpolysiloxane), LG-109 (polyalkylene), LG-126 (polyoxyethylenealkylene), and LG-299 (polyether) showed that the doses and types of antifoaming agents played a significant role in hydrogen production. During batch tests, LS-303 at 100μL/L resulted in the maximum hydrogen production rate (HPR) and hydrogen yield (HY) of 2.5L/L-d and 1.08mol H2/mol galactoseadded, respectively. The following continuously stirred tank reactor operated at 12h HRT with LS-303 at 100μL/L showed a stable HPR and HY of 4.9L/L-d and 1.17mol H2/mol galactoseadded, respectively, which were higher than those found for the control reactor. Microbial community analysis supported the alterations in H2 generation under different operating conditions and the stimulatory impact of certain antifoaming chemicals on H2 production was demonstrated., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Objective: The purpose of this study was to determine whether the occurrence of numerous colonic bubbles during CT colonography (CTC) performed with polyethylene glycol cleansing and oral iohexol fecal/fluid tagging could be prevented by use of simethicone., Subjects and Methods: Adults with suspected colonic neoplasia who had been randomly assigned to control and simethicone intervention groups underwent CTC after cleansing with 4 L of polyethylene glycol, tagging with 50 mL of 350 mg I/mL oral iohexol, and without (control) or with (intervention) oral administration of 200 mg of simethicone. Colonic segments in the control and intervention groups were evaluated for amount of colonic bubbles during CTC. A 6-point grading system was used in which 0 indicated no bubbles and 5 indicated that more than three fourths of the air-distended mucosa was covered with bubbles. The primary endpoint was a per-patient colonic bubble grade, derived as an average of the segmental grades., Results: Eighty adults with suspected colonic neoplasia were randomly assigned to the control (40 patients) and simethicone intervention (40 patients) groups. A total of 659 colonic segments in the control group and 689 segments in the intervention group were evaluated for amount of colonic bubbles during CTC. The per-patient colonic bubble score was significantly lower in the simethicone intervention group than in the control group. The mean score was 0.0±0.1 (SD) versus 1.2±0.8 (p<0.001; 95% CI for the mean difference, -1.4 to -1.0). In the intervention group, 673 (97.7%) segments were grade 0, and 16 (2.3%) were grade 1. In contrast, in the control group, 226 (34.3%) segments were grade 0; 173 (26.3%), grade 1; 175 (26.6%), grade 2; 45 (6.8%), grade 3; 23 (3.5%), grade 4; and 17 (2.6%), grade 5., Conclusion: The colonic bubbles associated with fecal/fluid tagging with iohexol can be successfully prevented by adding simethicone to the colonic preparation.

Foam control is an imperative need in biogas plants, as foaming is a major operational problem. In the present study, the effect of oils (rapeseed oil, oleic acid, and octanoic acid) and tributylphosphate on foam reduction and process performance in batch and continuous manure-based biogas reactors was investigated. The compounds were tested in dosages of 0.05%, 0.1% and 0.5% v/vfeed. The results showed that rapeseed oil was most efficient to suppress foam at the dosage of 0.05% and 0.1% v/vfeed, while octanoic acid was most efficient to suppress foam at dosage of 0.5% v/vfeed. Moreover, the addition of rapeseed oil also increased methane yield. In contrast, tributylphosphate, which was very efficient antifoam, was found to be inhibitory to the biogas process., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Pichia pastoris is a widely used host for recombinant protein production. The foaming associated with culturing it on a large scale is commonly prevented by the addition of chemical antifoaming agents or "antifoams." Unexpectedly, the addition of a range of antifoams to both shake flask and bioreactor cultures of P. pastoris has been shown to alter the total yield of the recombinant protein being produced. Possible explanations for this are that the presence of the antifoam increases the total amount of protein being produced and secreted per cell or that it increases the density of the culture. Antifoaming agents may therefore have specific effects on the growth and yield characteristics of recombinant cultures, in addition to their primary action as de-foamers.

Infacol (Forest Laboratories UK, Kent, UK) is a widely available over-the-counter preparation used to relieve colic symptoms in neonates and infants. The active ingredient is simeticone. No drug interactions with simeticone are documented in the current summary of product characteristics. The authors report the case of an infant with confirmed congenital hypothyroidism on levothyroxine who experienced a possible drug interaction with simeticone. Despite adequate levothyroxine dosage, thyroid stimulating hormone (TSH) was high, suggesting undertreatment. Questioning revealed the child was taking Infacol drops before feeds while on levothyroxine. The colic drops were immediately discontinued and TSH promptly normalised with a reduction in thyroxine requirement to an age appropriate dosage. Drug interaction of thyroxine with simeticone has not been reported previously and is not listed in the British National Formulary for Children. Clinicians and parents need to be aware of this interaction to avoid unnecessary undertreatment and prevent potential long-term neurological sequelae.

Background: Pichia pastoris is a widely-used host for recombinant protein production. Initial screening for both suitable clones and optimum culture conditions is typically carried out in multi-well plates. This is followed by up-scaling either to shake-flasks or continuously stirred tank bioreactors. A particular problem in these formats is foaming, which is commonly prevented by the addition of chemical antifoaming agents. Intriguingly, antifoams are often added without prior consideration of their effect on the yeast cells, the protein product or the influence on downstream processes such as protein purification. In this study we characterised, for the first time, the effects of five commonly-used antifoaming agents on the total amount of recombinant green fluorescent protein (GFP) secreted from shake-flask cultures of this industrially-relevant yeast., Results: Addition of defined concentrations of Antifoam A (Sigma), Antifoam C (Sigma), J673A (Struktol), P2000 (Fluka) or SB2121 (Struktol) to shake-flask cultures of P. pastoris increased the total amount of recombinant GFP in the culture medium (the total yield) and in the case of P2000, SB2121 and J673A almost doubled it. When normalized to the culture density, the GFP specific yield (μg OD₅₉₅⁻¹) was only increased for Antifoam A, Antifoam C and J673A. Whilst none of the antifoams affected the growth rate of the cells, addition of P2000 or SB2121 was found to increase culture density. There was no correlation between total yield, specific yield or specific growth rate and the volumetric oxygen mass transfer coefficient (k(L)a) in the presence of antifoam. Moreover, the antifoams did not affect the dissolved oxygen concentration of the cultures. A comparison of the amount of GFP retained in the cell by flow cytometry with that in the culture medium by fluorimetry suggested that addition of Antifoam A, Antifoam C or J673A increased the specific yield of GFP by increasing the proportion secreted into the medium., Conclusions: We show that addition of a range of antifoaming agents to shake flask cultures of P. pastoris increases the total yield of the recombinant protein being produced. This is not only a simple method to increase the amount of protein in the culture, but our study also provides insight into how antifoams interact with microbial cell factories. Two mechanisms are apparent: one group of antifoams (Antifoam A, Antifoam C and J673A) increases the specific yield of GFP by increasing the total amount of protein produced and secreted per cell, whilst the second (P2000 or SB2121) increases the total yield by increasing the density of the culture.

The aim of this work was to develop an economical bioprocess to produce the bio-ethanol from soybean molasses at laboratory, pilot and industrial scales. A strain of Saccharomyces cerevisiae (LPB-SC) was selected and fermentation conditions were defined at the laboratory scale, which included the medium with soluble solids concentration of 30% (w/v), without pH adjustment or supplementation with the mineral sources. The kinetic parameters - ethanol productivity of 8.08g/Lh, YP/S 45.4%, YX/S 0.815%, m 0.27h(-1) and microX 0.0189h(-1) - were determined in a bench scale bioreactor. Ethanol production yields after the scale-up were satisfactory, with small decreases from 169.8L at the laboratory scale to 163.6 and 162.7L of absolute ethanol per ton of dry molasses, obtained at pilot and industrial scales, respectively.

The objective of this research was to optimize sampling parameters for increased recovery and detection of airborne porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV). Collection media containing antifoams, activated carbons, protectants, and ethylene glycol were evaluated for direct effects on factors impacting the detection of PRRSV and SIV, including virus infectivity, viability of continuous cell lines used for the isolation of these viruses, and performance of reverse transcriptase PCR assays. The results showed that specific compounds influenced the likelihood of detecting PRRSV and SIV in collection medium. A subsequent study evaluated the effects of collection medium, impinger model, and sampling time on the recovery of aerosolized PRRSV using a method for making direct comparisons of up to six treatments simultaneously. The results demonstrated that various components in air-sampling systems, including collection medium, impinger model, and sampling time, independently influenced the recovery and detection of PRRSV and/or SIV. Interestingly, it was demonstrated that a 20% solution of ethylene glycol collected the greatest quantity of aerosolized PRRSV, which suggests the possibility of sampling at temperatures below freezing. Based on the results of these experiments, it is recommended that air-sampling systems be optimized for the target pathogen(s) and that recovery/detection results should be interpreted in the context of the actual performance of the system.

As foaming appears as a problem in chemical and fermentation processes that inhibits reactor performance, the eminence of a novel fluorocarbon-hydrocarbon unsymmetrical bolaform (FHUB: OH(CH2)11N+(C2H4)2(CH2)2(CF2)5CF3 I-) surfactant as an antifoaming agent as well as a foam-reducing agent was investigated and compared with other surfactants and a commercial antifoaming agent. The surface elasticity of FHUB was determined as 4 mN/m, indicating its high potential on thinning of the foam film. The interactions between FHUB and the microoganism were investigated in a model fermentation process related with an enzyme production by recombinant Escherichia coli, in V = 3.0 dm3 bioreactor systems with V(R) = 1.65 dm3 working volume at air inlet rate of Q(o)/V(R) = 0.5 dm3 dm(-3) min(-1) and agitation rate of N = 500 min(-1) oxygen transfer conditions, at T = 37 degrees C, pH(o) = 7.2, and C(FHUB) = 0 and 0.1 mM, in a glucose-based defined medium. As FHUB did not influence the metabolism, specific enzyme activity values obtained with and without FHUB were close to each other; however, because of the slight decrease in oxygen transfer coefficient, slightly lower volumetric enzyme activity and cell concentrations were obtained. However, when FHUB is compared with widely used silicon oil based Antifoam A, with the use of the FHUB, higher physical oxygen transfer coefficient (K(L)a) values are obtained. Moreover, as the amount required for the foam control is very low, minute changes in the working volume of the bioreactor were obtained indicating the high potential of the use of FHUB as an antifoaming agent as well as a foam-reducing agent.

Erythromycin production by Saccharopolyspora erythraea immobilized in 2% (w/v) calcium alginate or grown in medium containing 20 g sodium alginate/l inoculated with free cells was almost twice more than that of the control. S. erythraea did not consume alginate, agar, dextran, silicon antifoaming agent or cyclodextrin as a carbon source, although, all of these increased the production of erythromycin. Highest titer of erythromycin (2.3 times more than that of the control) was achieved in medium containing 1 g agar/l.

The ability of a silicone antifoam to retard foaming in a liquor prepared from potatoes is enhanced by the addition of ethoxylated nonionic surfactants. The enhancement is non-linear for surfactant concentration, with all 12 surfactants tested possessing a concentration at which foam heights strongly diminish, referred to as the surfactant critical antifoaming concentration (SCAFC). SCAFCs vary between surfactants, with lower values indicating better mass efficiency of antifoaming enhancement. SCAFCs decrease with degree of ethoxylation and decrease with the hydrophilic-lipophilic balance for ethoxylated nonionic surfactants. Surfactant addition produces a mixed water-surface layer containing surfactant and surface-active components in the potato medium. Surface tension reduction does not correlate well with antifoam performance enhancement. A model is proposed where surfactant adsorption promotes desorption of surface-active potato medium components from the water surface. At the SCAFC, desorption is not complete, yet the rate of bubble rupture is sufficiently enhanced to provide excellent foam control.

Antifoam (defoamer) chemicals are a crucial part of many commercial fermentation processes. Reviewed are the types of defoamers and their mode of operation. Also presented is a simple model, which simulates foam growth as functions of defoamer concentration, air hold-up, reactor volume and air flow rate.

Among the various lipidic and non-lipidic substances, normal alkanes within the chain lengths of C-12 to C-20 served as the best carbon substrates for the production of extracellular lipase by Pseudomonas species G6. Maximum lipase production of 25 U/ml of the culture broth was obtained by using n-hexadecane as the sole carbon substrate. The optimum pH of 8 and temperature of 34 + 1 degrees C were demonstrated for the production of lipase in n-hexadecane substrate. The optimum concentration of iron, which played a critical role on the lipase production, was found to be 0.25 mg/l. Lipase production could be enhanced to nearly 2.4-fold by using tributyrin at a concentration of 0.05% (v/v) in the culture medium. High recovery of the lipase protein (83%) from the culture broth was achieved by treating the culture supernatant with Silicone 21 Defoamer followed by ammonium sulfate (60% saturation) fractionation.

Aspergillus niger strains sensitive and resistant to toxic compounds of beet molasses grown in the presence of Spumol K were the object of the present studies. The antifoamer used diminished the number of mitochondria in both groups of strains and caused the reduction of their cristae in the sensitive ones. The disturbances in the ultrastructure of nucleus and mitochondria appeared mostly in sensitive strains. On the other hand, Spumol K presence in resistant strains not only increased the number of deposits of electron dense material in mitochondria, vacuoles, cytoplasm and in nuclear envelope but also was responsible for multivesicular body formation. The differences also existed in the ultrastructure of the cell wall: in the sensitive strains treated with Spumol K, the cell wall was completely deprived of fibrillar component, only granular component was present. In the resistant strains, granular component dominated, although fibrillar one was still visible. The present studies suggest that antifoamer in resistant strains becomes inactivated in different cell compartments, therefore its toxicity is lower than in sensitive strains where defence mechanism, inactivating toxic substances, is weaker and toxicity stronger.

The antifungal antibiotic rustmicin was detected in the fermentation broth of the actinomycete MA 7094 as a specific inhibitor of sphingolipid biosynthesis in Candida albicans and as a potent fungicidal agent against Cryptococcus neoformans. Taxonomic characterization by both classical means and PCR fingerprinting supported the assignment of the producing culture to the genus Micromonospora. Fermentation medium optimization studies showed that the concentration of tomato paste in the medium was critical to increased production of rustmicin by MA 7094. The stimulatory effect of tomato paste in the medium on rustmicin production appeared to be related to the maintenance of pH at or below a value of 6.0. Addition of the antifoam agent P-2000 to the fermentation was found to dramatically reduce the rustmicin titer, while substitution of another antifoam agent, UCON-LB625, resulted in a 100% increase in the amount of rustmicin detected. After fermentation optimization studies and the generation of a non-sporulating mutant of MA 7094, the rustmicin titer was increased from an initial titer of 10mg/liter to 145 mg/liter.

Helicobacter pylori is killed in vitro by polyoxyethylene acyl esters and ethers similar to simethicone emulsifiers in therapeutic antifoams. The MBC of these compounds for Helicobacter pylori was less than 20 micrograms/ml, while other gram-negative bacteria were unaffected by much higher concentrations of up to 50 mg/ml.

The antifoaming agent simethicone (Lefax), the protease inhibitor gabexate mesilate (FOY), the antimycotic ketoconazole, and the hydroxyl scavangers dimethylsulphoxide (DMSO) and allopurinol were investigated for growth inhibition of Helicobacter pylori and representative strains of other bacterial species. H. pylori were selectively inhibited by 64-128 mg/L of simethicone, 64-128 mg/L gabexate mesilate, and 16-64 mg/L ketoconazole. Dimethylsulphoxide and allopurinol showed no antibacterial effect at concentrations used therapeutically. It is concluded that gabexate mesilate, ketoconazole and, particularly, simethicone are candidates for treatment of H. pylori infection.

Addition of high concentrations of silicone antifoam (AF) to a suspension of hybridoma cells in a bubble column reduces the death rate when using medium without a protective component. In contrast, high AF concentrations can cause detrimental effects in a sparged medium with a protective component, such as is applied for large-scale animal cell cultures.

Antifoam microembolisms in patients that undergo open heart surgery, represent a risk for postoperative complications. We decided to study its frequency in an autopsy population of patients who died after heart surgery. Forty-five patients were selected and histological sections from the kidneys were studied under light microscopy, scanning electron microscopy and X-ray microanalysis. Thirty-six cases (80%) showed microemboli in the glomerular capillaries lumens. There was a positive correlation between the number of particles found and the length of the surgery. Microemboli were composed of an amorphous fraction and a particulated one composed of silicon. In vitro experimentation demonstrated that the particles are capable to induce cell lysis in a dose related manner. They also are susceptible of been phagocitated by macrophages. We conclude that bubble oxygenator are capable to induce microembolisms in a high percentage of the cases studied. Components of the microemboli are cytotoxic. Therefore microembolisms could be participating in the morbidity of patients subjects to cardiopulmonary bypass.

Effects of foaming agents (blood plasma, bovine serum albumin, polyvinyl-pyrrolidinone) and defoaming agents (octanol, n-foam) on manometric determination of carbonic anhydrase activity in intact erythrocytes of fish were examined. Foaming agents abolished the activity of red cells. Defoaming agents increased the activity and negated any differences in carbonic anhydrase activity between whole blood (red cells in plasma) and "Cortland" blood (red cells in saline). It is concluded that effects of plasma on the carbonic anhydrase activity of intact erythrocytes of fish measured using the modified boat technique are largely nonspecific and related to reagent foaming during mixing, rather than to the action of a specific enzyme inhibitor.

Oils used as antifoaming agents in fermentation are subjected to oxidation to form various products, such as aldehydes, carboxylic acids, peroxides, etc. The negative effect of such products on biosynthesis of chlortetracycline by strains VUA 84 and Iz 22/VUPL of Str. aureofaciens was recorded. The level of the oil oxidation was characterized by the contents of peroxides and epihydrinaldehydes. The Kreiss qualitative test was modified for quantitative estimation of epihydrinalydehydes. The oil antifoaming agents characterized by the routine parameters used in determination of oil quality, such as acid number, saponification number and iodine number. In the control experiments lard and soybeen oil were oxidized by air at a temperature of 100 degrees C without an antioxidant (2,6-ditetrabutyl-4-methylphenol). The oil antifoaming agents such as soybeen oil and lard were tested in biosynthesis of chlortetracycline carried out in flasks and pilot plant 750 1 apparatus. Antioxidant 4K, an alkylphenol antioxidant, in a 2% concentration proved to be effective for prevention of oxidation and nontoxic for the culture.

A method is described for inducing experimental aerogastria (flatulence) in human volunteers by the ingestion of "whipped" egg-white. Abdominal ultrasonography was used to measure the distension of the stomach and its interference with the visualization of organs such as gall bladder, pancreas and left kidney lying behind the stomach. A double-blind crossover comparison of Flatoril, a mixture of dimethicone (200 mg) and clebopride (0.5 mg) against placebo clearly demonstrated the superior antifoaming activity of the former both in terms of reduced gastric distension and of improved visualization of organs otherwise hidden by the foam-filled stomach.

The break up time (B.U.T.) of the precorneal film has been studied before and after application of 34 different vehicles. The material examined comprised 646 eyes. Maximum increase of the B.U.T. was obtained with 2% methyl cellulose (four times) and 10% polyvinyl alchohol (seven times). These vehicles in the usually employed concentrations, fat-free ointment (polyethylene glycol), acetyl cysteine and polysaccharide (dextran) affected a less pronounced prolongation. The B.U.T. was reduced four or five times by fatty, anhydrous ointments and by silicone oil, about two or three times by emulsions and oils, and twice by 0.01% benzalkonium chloride. The clinical significance of the B.U.T. alterations is discussed.

The effect of sodium dodecylbenzene sulfonate (sulfonol) and certain froth breakers on the activity of endonuclease was studied in the cultural broth of Serratia marcescens in order to find out whether sulfonol could be used for limiting the infection. Sulfonol was found to have no effect on the cultural growth; it increased the activity of endonuclease in the cultural broth, and the peak of the activity appeared earlier than in the control medium. Propanol B-400 was shown to be the best froth breaker.

The growth kinetics of a microorganism with high affinity for liquid hydrocarbon which has a low solubility in water was investigated for Candida intermedia IFO 0761 in our previous work. The microorganism contained a hydrocarbon pool in and/or on the cell. The transfer of water-soluble substrates to the cell was not the rate-limiting step in the growth of C. intermedia accompanied by clump formation with liquid hydrocarbon. The operating conditions necessary for the oxygen supply for the growth were adequate for the growth of C. intermedia on n-tetradecane. The saturation kinetics was valid for the specific growth rate of C. intermedia and specific concentration of hydrocarbon per unit cell mass; the specific growth rate was expressed by the following equation: (formula: see text).

The double contrast method in the examination of the stomach has made possible the radiologic diagnosis of the surface lesions of the mucosa, eg, erosions and early gastric cancer. Changes in the patterns of areae gastricae can be visualized with a good contrast medium. We used a new, more physiologic in vitro method to compare contrast media and study the amounts of adsorption, the degrees of visualization of areae gastricae, and the effects of antifoam solution and blood on media adsorption. EZ-HD surpassed other contrast media on the Scandinavian market in total adsorption on the mucosa and the visualization of areae gastricae. Blood significantly reduces the adsorption of all media, while antifoaming agents have little or no effect.

Defoaming of the medium by a rotating turbine during yeast cultivation, in contrast to defoaming by oil, results in fading away of cells of higher age categories and in an increase of dead cells proportion in the population. The negative effect of the mechanical defoaming device did not manifest itself in the amount of biomass obtained but in the cell numbers observed.

The effect of temperature, aeration and various foam suppressors on the growth of a mutant of Aspergillus terricola H-20 and on its production of proteolytic enzymes was studied. A high level of the proteolytic activity (12-15 PU/ml) was found at 28-30 degree C in conditions of aeration with the rate of oxygen dissolution being 0.38-0.86 g of oxygen per litre per hour. Synthesis of the enzyme was inhibited by a decrease in temperature to 22-24 degree C, a surplass (1.07 g O2 per litre per hour) or insufficient (0.18 g O2 per litre per hour) content of oxygen in the medium, and by addition of animal (sperm-whale) fat as a froth breaker to the medium. The best rate of protease biosynthesis was obtained upon stepwise addition of sunflower oil to the cultural broth. The best synthetic froth breakers for biosynthesis of the proteolytic enzyme are adecanol at a concentration of 0.1-1% and polymethylsiloxane PMS-A 154 as a water emulsion at a concentration of 0.5% of the medium volume.

A mixture of a cell culture-adapted strain (C-486) of calf rotavirus and poliovirus type 1 (Sabin) was prepared in tryptose phosphate broth containing 0.1% uranine (physical tracer) and antifoam at a final concentration of 0.001%. By using a six-jet Collison nebulizer, the mixture was aerosolized into a 300-liter stainless-steel rotating (4 rpm) drum. The temperature of the air inside the drum was kept at 20 +/- 1 degrees C, and the virus aerosols were held at the following three levels of relative humidity (RH): low (30 +/- 5%), medium (50 +/- 5%), and high (80 +/- 5%). An all-glass impinger, containing 10.0 ml of tryptose phosphate broth with antifoam, was used to collect samples of air from the drum. Both viruses were propagated and quantitated in MA-104 cells. The calf rotavirus was found to survive well at mid-range RH, where 60% of the infectious virus could be detected even after 24 h of virus aerosolization. At the low RH, the half-life of the infectious rotavirus was ca. 14 h. On the other hand, no infectious poliovirus could be recovered from the drum air at the low and medium RH. At the high RH, more than 50% of the infectious rotavirus became undetectable within 90 min of aerosolization. In contrast to this, the half-life of the poliovirus at the high RH was about 10 h. These data, based on the aerosolization of virus mixtures, therefore suggest that there is a pronounced difference in the way RH influences the airborne survival of these two types of viruses held under identical experimental conditions.

The data on the effect of chemical foam suppressors of various classes on the morphogenesis of 2 strains of Streptomyces rimosus are presented. Correlation between the age of the culture and its reaction to unfavourable conditions is confirmed. During the first 24 hours of the growth the culture is most sensitive to low aeration rates, addition of the foam suppressors, fat deficiency in the medium. Among the foam suppressors used propinol B-400 had the most significant effect on the cells: destruction of the cell coating, marked changes in the morphogenesis and nucleocytosis of the hyphae of the second generation responsible mainly for the antibiotic biosynthesis. A more active strain was more subject to the foam suppressor toxic effect.

The effect of chemical foam suppressors of various classes on the intensity of Streptomyces rimosus respiration, concentrations of dissolved oxygen and carbon dioxide and gas levels in the fermentation broth of oxytetracycline was studied. Its was shown that addition of the foam suppressors, as a rule, resulted in a decreased rate of the oxygen mass transfer due to the decreased surface of the phase contact gas-liquid. This decrease was not so significant as that in case of uninhibited intensity of the fermentation broth foaming. A different character of the effect of different foam suppressors on the biosynthetic process was noted. The effect of the foam suppressors was decreased by their regular addition in low amounts.