Ml Of Surfactant Research Articles

E-Cigarette Aerosol Inhibition of Compositionally Different Surfactants

Introduction: Pulmonary surfactant lines the alveolar surface where it reduces surface tension (ST) thereby facilitating breathing with minimal effort. As such, impairment of surfactant’s surface tension reducing function can contribute to lung injury. Isolated surfactant from the lung consists of up of 85-90% by weight saturated and unsaturated phospholipids, 5-10% neutral lipids, mainly cholesterol, and 10% surfactant proteins, designated SP-A, SP-B, and SP-C. However, studies examining surfactant function and dysfunction have often utilized surfactants with simpler compositions. One recent area of interest is the impact of e-cigarette (EC) generated aerosols on surfactant. EC use remains a popular habit despite reports of vaping associated acute lung injury. Upon inhalation, EC aerosol comes into direct contact with pulmonary surfactant and previous studies have demonstrated that EC aerosol exposure can impair surfactant function using either bovine lipid-extracted surfactant (BLES) or simple lipid mixtures. Comparing inhibition by EC aerosol of a more diverse set of surfactant preparations can further elucidate which components of surfactant are most affected by EC aerosol. We hypothesized that EC aerosol would cause varying degrees of functional inhibition in compositionally different surfactants. Methods: The following surfactant preparations were tested: BLES, BLES + SP-A, natural bovine, SP-A deficient bovine, and synthetic surfactants composed of saturated lipids + cholesterol + SP-C, and saturated + unsaturated lipids + cholesterol + SP-C. To test the exposure to EC aerosol, 2ml of surfactant was placed in a syringe (30ml) attached to an EC. The generated aerosol was drawn into the syringe for 30 sec and then expelled, this was repeated 30 times. The functional impact was then tested on a constrained sessile drop surfactometer to analyse changes in ST reduction. Results: Upon exposure to EC aerosol, natural bovine surfactant had significantly higher minimum ST compared to non-exposed and BLES. This difference did not appear to be mediated by SP-A. Synthetic lipid mixtures containing only saturated phospholipids (DPPC) were not significantly inhibited by EC aerosol, but the addition of unsaturated lipids resulted in increased minimum ST. Conclusion: Functional impairment of pulmonary surfactant due to EC aerosol is dependent on aerosol interaction with unsaturated lipids. This effect is more pronounced in natural complete surfactants. Western, NSERC, OGS. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Prevention of Neonatal Respiratory Distress Syndrome by Antenatal Steroid Administration

Background: Exposure to antenatal steroids (A.N.S.) decreases the incidence of neonatal respiratory distress syndrome and other morbidities in premature infants. If left untreated, death may occur from progressive hypoxia and respiratory failure. In survivors, resolution begins between 2 to 4 days.Objective: To determine the efficacy of antenatal steroids in preventing respiratory distress syndrome in premature neonates. Material and Methods: A randomized trial, analytical study with a sample size of 152 was conducted in the Department of Obstetrics and Gynecology, Hayatabad Medical Complex, Peshawar. The study duration was from 16th July 2022 to 18th June 2023. The study included neonates born at 24 to 34 weeks of gestation. Neonates born at fewer than 34 (24 to 34 weeks) weeks gestation were given 3 or 4 mL of surfactant from lipids taken from calf lung lavage. The proteins were decreased from more than 10% to less than 1% of the phospholipid weight using the lipid extraction procedure. The chi-square test was used.Results: Analysis was performed for the 152 VLBW infants the infants who received antenatal corticosteroids was 37 to 45% were gestational age 2434 weeks. While infants who received surfactant decreased gradually as gestational age increased. A significant decrease in surfactant used in the late period, with a 510% reduction in each gestational group.Conclusion: This study reaffirms the value of administering antenatal steroids to premature neonates. This study showed the potential use of ante natal steroids has effectively mitigated respiratory distress syndrome. These findings underscore the significance of antenatal corticosteroid therapy in reducing respiratory morbidity in preterm neonates and emphasize its role in enhancing lung maturation and neonatal outcomes.Keywords: Antenatal corticosteroids, Preterm infants, Respiratory distress syndrome, Surfactant, Very low birth weight.

Preparation of bacteriostatic microspheres loading potassium diformate using emulsification/external gelation

Potassium diformate (KDF) is a good substitute for antibiotics in animal feed. Based on the response surface methodology for optimizing the preparation conditions of microspheres. The optimal formulation was as follows: the concentration of ALG was 2 %, the concentration of CaCl2 was 2 %, and 0.4 mL of surfactant. The objective of the present study was to microencapsulate the KDF antibacterial microspheres by emulsification/external gelation. The structure, morphology and thermal properties of the obtained microspheres were characterized by XRD, SEM, FT-IR and TGA. Additionally, the encapsulation efficiency (EE%), loading capacity (LC%), antibacterial and slow-release properties of the prepared microparticles were evaluated. The results show that the optimized microspheres had spherical in morphology, in size, from 2 μm to 10 μm. Finally, the results of the in vitro antibacterial test showed that, when the concentration of antibacterial microspheres was 96 mg/mL, the antibacterial rates against Escherichia coli (E. coli) and Staphylococcus aureus were 89 % and 87 %, respectively, which effectively inhibited the excessive growth of the bacteria. The release kinetics model of the KDF microspheres in vitro revealed that the first-order release mechanism and Hixon-Crowell release mechanism were the primary release mechanisms, and the action time in the intestine could be delayed to 5 h.

An experimental investigation of nanoemulsion enhanced oil recovery: Use of unconsolidated porous systems

Utilization of nanoparticles in oil and gas industry has attracted considerable attention of engineers and researchers. In this article, the feasibility of nanoemulsion flooding is investigated as a method for Enhanced Oil Recovery (EOR) through coreflooding experiments, using a packed bed and real reservoir fluids. Nine different mixtures of the solvent, surfactant, and nanoparticles in the form of a nanoemulsion phase are generated and used to recover the oil in the context of an EOR process. Various tests are conducted to determine the properties of porous medium and fluids. To study the production performance of this EOR technique, pressure drop across the packed bed are measured, along with the volumetric measurements of the produced fluids. A baseline injection scheme using seawater is also performed. All the nanoemulsion fluids are synthesized using the same base seawater. The Taguchi experimental design approach is employed in this research to design the experiments. The effects of nanoparticles concentration, along with those of surfactant and solvent components of the injection fluid on the oil recovery at the laboratory scale are investigated using the Analysis of Variance (ANOVA) method. Comparing the performance of waterflooding (WF) and nanoemulsion flooding, enhancement in the Recovery Factor (RF) by using emulsions is between 40–107%. Both the pressure and pressure fluctuations are surprisingly higher in the case of WF in comparison to the emulsion flooding. It is also found that under optimal concentration conditions (0.01 g of nanoparticles, 0.015 mL of surfactant, and 1 mL of solvent per one liter of brine), a recovery factor of up to 60% is achieved.

First Report of Rust Caused by Puccinia carduorum on Italian thistle in Tunisia.

Italian thistle (Carduus pycnocephalus L.) is a common and increasingly important weed in Tunisia. It is also problematic in the western United States and a target of biological control. In surveys conducted in northern Tunisia from 2003 to 2005, Italian thistle plants in many locations were found diseased by rust. Eighty-five isolates of rust were collected from Italian thistle during these surveys. Each isolate was collected from a single plant and stored individually as mixtures of urediniospores and teliospores at 4°C or in liquid nitrogen. Urediniospores and teliospores of all isolates were similar in morphology and matched the description of Puccinia carduorum Jacky (3). Isolate B1003 (BPI No. 878207), collected from Béja, Tunisia, was arbitrarily selected for further study. Comparison of internal transcribed spacer (ITS) regions of B1003 (GenBank Accession No. EF050059) with other ITS sequences indicated a 97% similarity to P. carduorum (GenBank Accession No. PCU57351) from Carduus nutans subsp. leiophyllus. Eight Italian thistle plants, grown from seeds collected in Béja, were inoculated in the 3- to 5-leaf stage with urediniospores of B1003 by spraying plants with an aqueous suspension of urediniospores at 106 spores per ml with approximately 0.03 ml of surfactant until they were thoroughly wet. Four plants were sprayed with water plus surfactant only. All plants were covered with plastic bags and placed in a growth chamber at 18/20°C night/day temperatures. Bags were removed 24 h after inoculation and plants were monitored daily for symptoms. Plants sprayed with water plus surfactant only did not develop symptoms. Six inoculated plants developed disease symptoms similar to those observed on samples collected during the surveys. White flecks appeared within 7 days of inoculation and developed into brown pustules 10 days after inoculation. Pustules enlarged and produced urediniospores until they covered both sides of diseased leaves. One month after appearance of symptoms, diseased leaves turned yellow and died. Urediniospores from these plants were used to inoculate six plants each at the 2- to 5-, 6- to 8-, and >8-leaf stages. All plants became diseased and produced uredinia. Plants in the 2- to 5-leaf stage were more severely diseased than other plants. P. carduorum was introduced to the United States in a field test for control of C. nutans subsp. leiophyllus (musk thistle) and has become established in a number of states (1). An isolate of this fungus has also been found from C. tenuiflorus (slender-flower thistle) in California (4). However, neither isolate causes substantial disease on Italian thistle from California (2,4). Isolates of P. carduorum from C. pycnocephalus in Greece, Italy, and Turkey caused little disease on most Italian thistle collections from California (2), indicating variability in susceptibility among plants as well as in virulence among rust isolates from different geographical locations. To our knowledge, this is the first report of P. carduorum parasitizing Italian thistle in Tunisia. Tests will be conducted to determine the host range of this isolate among C. pycnocephalus collections and other species.

Effect of surfactant alkyl chain length on soil cadmium desorption using surfactant/ligand systems

The effect of surfactant alkyl chain length on soil Cd desorption was studied using nonionic surfactants of polyethylene oxide (PEO) of PEO chain lengths of 7.5 (Triton X-114), 9.5 (Triton X-100), 30 (Triton X-305), or 40 units (Triton X-405) in combination with the I − ligand. Triplicate 1 g soil samples were equilibrated with 15 ml of surfactant–ligand mixture, at concentrations of 0.025, 0.50 or 0.10, and 0.0, 0.168 or 0.336 mol/l, respectively. After shaking the samples for 24 h, the supernatant fraction was analyzed for Cd content to determine the percent of Cd desorbed from the soil. After five successive washings, 53%, 40% and 25% of Cd had been desorbed by 0.025, 0.050 or 0.10 mol/l of Triton X-114, respectively, in the presence of 0.336 mol/l of I −, whereas with the same conditions, Triton X-100 desorbed 61%, 57% and 56% Cd and either Triton X-305 or Triton X-405 desorbed 51, 40 and 14 to 16% Cd. The most efficient Cd desorption was obtained using 0.025 mol/l Triton X-100 in admixture with 0.336 mol/l I −. Increased surfactant concentration was detrimental to Cd desorption consistent with a process that blocked ligand access to the soil particle surface. After 5 washings,the cumulative cadmium desorption decreased with increasing surfactant alkyl chain length, indicating that the metal–ligand complexes are preferably stabilized by the micelles' hydrophobic octyl phenyl (OP) group rather than by the hydrophilic PEO group. In the absence of ligand, the surfactants alone desorbed less than 1% Cd from the contaminated soil, suggesting that the ligand, rather than the surfactant, extracts the metal, to be subsequently stabilized within the surfactant micelles.

Relationship between surface tension of upper airway lining liquid and upper airway collapsibility during sleep in obstructive sleep apnea hypopnea syndrome.

Lowering surface tension (gamma) of upper airway lining liquid (UAL) reduces upper airway opening (anesthetized humans) and closing (anesthetized rabbits) pressures. We now hypothesize that in sleeping obstructive sleep apnea hypopnea syndrome (OSAHS) patients lowering gamma of UAL will enhance upper airway stability and decrease the severity of sleep-disordered breathing. Nine OSAHS patients [respiratory disturbance index (RDI): 49 +/- 8 (SE) events/h, diagnostic night] participated in a two-part, one-night, polysomnography study. In the first part, upper airway closing pressures (during non-rapid eye movement sleep, Pcrit) were measured and samples of UAL (awake) were obtained before and after 2.5 ml of surfactant (Exosurf, Glaxo Smith Kline) was instilled into the posterior pharynx. The gamma of UAL was determined with the use of the "pull-off" force technique. In the second part, subjects received a second application of 2.5 ml of surfactant and then slept the remainder of the night (205 +/- 30 min). Instillation of surfactant decreased the gamma of UAL from 60.9 +/- 3.1 mN/m (control) to 45.2 +/- 2.5 mN/m (surfactant group) (n = 9, P < 0.001). Pcrit decreased from 1.19 +/- 1.14 cmH2O (control) to -0.56 +/- 1.15 cmH2O (surfactant group) (n = 7, P < 0.02). Compared with the second half of diagnostic night, surfactant decreased RDI from 51 +/- 8 to 35 +/- 8 events/h (n = 9, P < 0.03). The fall in RDI (deltaRDI) correlated with the fall in gamma of UAL (deltagamma) (deltaRDI = 1.8 x deltagamma, r = 0.68, P = 0.04). Hypopneas decreased approximately 50% from 42 +/- 8 to 20 +/- 5 events/h (n = 9, P < 0.03, paired t-test). The gamma of UAL measured the next morning remained low at 49.5 +/- 2.7 mN/m (n = 9, P < 0.001, ANOVA, compared with control). In conclusion, instillation of surfactant reduced the gamma of UAL in OSAHS patients and decreased Pcrit and the occurrence of hypopneas. Therapeutic manipulation of gamma of UAL may be beneficial in reducing the severity of sleep-disordered breathing in OSAHS patients.

Amelioration of water repellency in highly managed soils and the enhancement of turfgrass performance through the systematic application of surfactants

Water repellency is a common phenomenon in highly managed golf course soils. Considerable speculation exists on the cause of water repellency, yet little definitive research has been conducted to elucidate those factors contributing to its cause. In golf course soils, water repellency has been managed through the prophylactic application of surfactants to turf areas exhibiting visual symptoms, commonly referred to as localized dry spots (LDS) and characterized as irregular areas of stressed and declining turf. Soils in affected areas are often dry, have poor infiltration rates, and are non-wettable. The problem may be observed on fairways but is more prevalent on sand-based tees and greens. While surfactants have been used commonly as management tools, few studies have evaluated them beyond the traditional use as materials to eliminate LDS.This study evaluated the effectiveness of a new surfactant formulation (Primer®604) for amelioration and management of soil water repellency (as measured using water drop penetration time [WDPT]), improvement in a range of turf performance parameters (turf quality, area affected by LDS, percent wilt under stress), and estimation of available soil water. Thirty-six sand-based tees on a course with a history of severe water repellency were treated with 0, 125, or 185ml of surfactant (in 8l of water) per 100m2. Treatments were applied monthly for three months and ratings were taken over a four-month period beginning with the initial treatment applications.At study initiation, all tees exhibited LDS symptoms. Surfactant treatment significantly reduced soil water repellency as compared to the untreated control. Reduction in soil water repellency lasted for a minimum of one month. After two surfactant treatments, turf quality was improved and both LDS and afternoon turf wilting were nearly eliminated on treated tees, while severity increased in the untreated controls. Reduction in water repellency corresponded with enhanced turf performance ratings. Based on visual assessment of soil core samples, estimated hydration uniformity and available water were improved in treated soils. Systematic treatment with Primer®604 reduced soil water repellency, enhanced turf performance, improved uniformity of turf, and increased available water in soils.

Prevention of Neonatal Respiratory Distress Syndrome by Tracheal Instillation of Surfactant: A Randomized Clinical Trial

With a randomized clinical trial, the possibility was assessed that a tracheal instillation of pulmonary surfactant prior to the first breath might prevent the development of some of the signs of neonatal respiratory distress syndrome. Of the 72 infants in the trial, all born at a gestational age of less than 30 weeks, 39 received 3 or 4 mL of surfactant, prepared from the lipids extracted from calf lung lavage. The treatment resulted in a significantly improved gas exchange during the first 72 hours of life. On the average, the arterial/alveolar PO2 ratio was 0.15 higher for the treated infants, and only about half as much extra oxygen had to be supplied. The respiratory support (peak inspiratory pressure X frequency) could be lowered significantly. Pulmonary interstitial emphysema occurred in 13 of the 33 control infants, but in only three of the 39 treated infants. Six of the control infants died in the neonatal period, but only one treated infant died. It is concluded that surfactant supplementation prior to the first breath is feasible and is of value as protection against the respiratory distress syndrome and the negative effects of hypoxia and ventilatory support.