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Ionically crosslinked hydrogels containing metal coordination motifs have piqued the interest of researchers in recent decades due to their self-healing and adhesive properties. In particular, catechol-functionalized bulk hydrogels have received a lot of attention because of their bioinspired nature. By contrast, very little is known about thin viscoelastic membranes made using similar chelator–ion pair motifs. This shortcoming is surprising because the unique interfacial properties of these membranes, namely, their self-healing and adhesion, would be ideal for capsule shells, adhesives, or for drug delivery purposes. We recently demonstrated the feasibility to fabricate 10 nm thick viscoelastic membranes from catechol-functionalized surfactants that are ionically crosslinked at the liquid/liquid interface. However, it is unclear if the vast know-how existing on the influence of the chelator–ion pair on the mechanical properties of ionically crosslinked three-dimensional (3D) hydrogels can be translated to two-dimensional (2D) systems. To address this question, we compare the dynamic mechanical properties of ionically crosslinked pyrogallol functionalized hydrogels with those of viscoelastic membranes that are crosslinked using the same chelator–ion pairs. We demonstrate that the storage and loss moduli of viscoelastic membranes follow a trend similar to that of the hydrogels, with the membrane becoming stronger as the ion–chelator affinity increases. Yet, membranes relax significantly faster than bulk equivalents. These insights enable the targeted design of viscoelastic, adhesive, self-healing membranes possessing tunable mechanical properties. Such capsules can potentially be used, for example, in cosmetics, as granular inks, or with additional work that includes replacing the fluorinated block by a hydrocarbon-based one in drug delivery and food applications.

Drilling the wellbore into subsurface formations is the earliest stage in the life of a well that requires a suitable drilling fluid with good rheological and filtration control characteristics to achieve a successful drilling operation. This paper reports on the formulation of water-based drilling mud using kaolin clay reinforced with biopolymer, surfactant, and limestone from Tanzania. The raw materials used for the formulation were characterized using XRD, XRF, FTIR, and TGA techniques. The rheological properties, filtration loss, pH, and density of the formulated mud were measured using a viscometer, filter press, pH meter, and mud balance, respectively. The XRD results revealed kaolinite and quartz as the main minerals in all kaolin clay samples which were in agreement with the FTIR findings. The mineralogical composition of the kaolin was observed to vary with the mining sites and influenced the rheological and filtration control characteristics of the mud. The beneficiated drilling mud showed better rheological and filtration control characteristics than the commercially available bentonite mud in Dar es Salaam market and was comparable with the API standards. These results, therefore, are not only new but rather important and novel information on the potential of kaolin clay for the formulation of water based drilling mud. Keywords: Water-based drilling mud, kaolin clay, biopolymers, bentonite, surfactant

Comparative study is carried out between nano fluid (nf) CuO+ZnO+H_2O and water (H_2O) as solitary fluid through experimental and simulation result. The outcome of nano fluid and solo H_2O flowing inside rectangular strip mini channel with or without mini insert were admit, for study the conduct of fluid flow and heat-exchange features like Nusselt number (Nu), Friction factor (f), Effectiveness (Ɛ), Coefficient of thermal transfer (h), Heat transfer factor (Q), Nu/Nus, f/fs, thermal-performance factor (TPF), Number of transferring unit (NTU) and Reynolds’s number (Re). During composing of nano fluid 0.01% volume fraction, 10-20 nm size nano particles were mixed with 0.5ml CTAB surfactant. Experimentation was managed for different operating parameters under counter flow conditions, where nano fluid is flowing inside mini channel of 2 mm diameter with flow rate 0.0001562 kg/sec (9.37 ml/min) to 0.006255 kg/sec (375.30 ml/min) and hot water is flowing inside the concentric tube of 3cm diameter with flow rate of 0.000782 kg/sec (46.92 ml/min). The operating temperature of nano fluid and hot water were 303K and 323K. As per obtained results, the proposed composition of nanofluid showed better performance than normal water due to better thermal conductivity and extra molecular area gain in nanofluid due to addition of nano particle with base fluid, Thus, it improved the results 18%-21% approximately. Whereas better optimum results were observed in case of rectangular mini channel with mini insert compared with other geometry because of rich turbulency gain and extra exposed area due to mini insert. It affects optimum results in terms of better performance up to 9%-15% compared with simple micro channel without inserts.

Background: Clinical and radiographic criteria are traditionally used to determine the need for surfactant therapy in preterm infants. Lung ultrasound is a bedside test that offers a rapid, radiation-free, alternative to this approach. Objective: To conduct a systematic review and meta-analysis to determine the accuracy of a lung ultrasound score (LUS) in identifying infants who would receive at least one surfactant dose. Secondary aims were to evaluate the predictive accuracy for ≥2 doses and the accuracy of a different image classification system based on three lung ultrasound profiles. Methods: PubMed, SCOPUS, Biomed Central, and the Cochrane library between January 2011 and December 2021 were searched. Full articles enrolling preterm neonates who underwent lung ultrasound to predict surfactant administration were assessed and analyzed following Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) and QUADAS-2 guidelines. Results: Seven prospective studies recruiting 697 infants met the inclusion criteria. Risk of bias was generally low. Oxygen requirement, clinical and radiographic signs of respiratory distress syndrome were used as reference standards for surfactant replacement. The summary receiver operator characteristic (sROC) curve for LUS predicting first surfactant dose showed an area under the curve (AUC) = 0.88 (95% confidence interval [CI]: 0.82-0.91); optimal specificity and sensitivity (Youden index) were 0.83 and 0.81 respectively. Pooled estimates of sensitivity, specificity, diagnostic odds ratio, negative predictive value, and positive predictive value for LUS predicting the first surfactant dose were 0.89 (0.82-0.95), 0.86 (0.78-0.95), 3.78 (3.05-4.50), 0.92 (0.87-0.97), 0.79 (0.65-0.92). The sROC curve for the accuracy of Type 1 lung profile in predicting first surfactant dose showed an AUC of 0.88; optimal specificity and sensitivity were both 0.86. Two studies addressing the predictive accuracy of LUS for ≥2 surfactant doses had high heterogeneity and were unsuitable to combine in a meta-analysis. Discussion: Despite current significant variation in LUS thresholds, lung ultrasound is highly predictive of the need for early surfactant replacement. This evidence was derived from studies with homogeneous patient characteristics and low risk of bias.

Self-emulsifying drug delivery system (SEDDS), a type of lipid-based technology which are isotropic mixtures of oil, surfactant, solvent, and co-solvents generated by the activity of liquid or solid self-emulsifying ingredients onto powders. It shown interest in the recently for enhancement of solubility and bioavailability of poorly water-soluble drugs (BCS-II). With the novelty of research in this field, novel Excipients have been design with novel properties for enhances solubility, Bioavailabity and oral absorption to achieving target response. Self-emulsifying drug delivery systems (SEDDS) emerged as an insightful approach for delivering highly hydrophobic entities to enhance their bioavailability. SEDDS increase drug bioavailability in addition to improving the solubility of poorly soluble drugs by a number of additional potential pathways, such as avoiding the hepatic first-pass effect, blocking P-gp efflux, and overcoming resistance to metabolism by the cytochrome P450 family of enzymes in the gut and liver. Conventional SEDDS were developed in a liquid form which owned numerous overcome like low stability and drug loading efficiency, fewer choices of dosage forms and irreversible precipitation of drug or excipients. To address these curbs solid-SEDDS (S-SEDDS) was introduced as an efficient strategy that combined advantages of solid dosage forms such as increased stability, portability and patient compliance along with substantial improvement in the bioavailability. This review highlights parts of SEDDS, and their characterization evaluation. Which are completely summarized via different techniques.

Prematürelerde görülen respiratuvar distres sendromunda surfaktanın klinik kullanıma girmesi ile birlikte prematüre bebeklerdeki yaşam oranı dramatik olarak artmıştır. Surfaktanın akciğerlere iletiminde kullanılan yöntemler zaman içerisinde daha az invaziv ve hatta invaziv olmayan yöntemlere doğru evrilmeye başlamıştır. Surfaktanın ince kateter ile uygulanması, bir larengeal veya suproglottik havayolu cihazı kullanılarak, farengeal uygulama ile ve aerosolize şekilde verilmesi gibi yeni yöntem çalışmaları giderek artmaktadır. Böylece, immatür akciğerin klasik olarak kabul edilen entübasyon, pozitif basınçlı ventilasyon ve mekanik ventilasyonun zararlı etkilerinden korunması hedeflenmiştir. İnce kateter ile surfaktan uygulanması metodu ile yapılan çok sayıda çalışma ve meta-analizin sonuçları entübasyon, surfaktan uygulanması ve pozitif basınçlı ventilasyon metotları ile karşılaştırıldığında mekanik ventilasyon ihtiyacı ve süresi, bronkopulmoner displazi insidansı ve neonatal mortalite oranlarında azalmaya neden olduğu gösterilmiştir. Ancak çalışmalarda premedikasyon yönetimi ve solunum desteği türü, uygulanan surfaktan türü gibi birçok konuda heterojenite mevcuttur. Supraglottik hava yolu cihazı, farengeal uygulama ve aerosolizasyon uygulamaları özellikle laringoskopinin dezavantajlarını ortadan kaldırması ve daha da az invaziv olmaları, daha az tecrübe ve yetenek gerektirmeleri nedenleri ile ince kateter ile surfaktan uygulanması yönteminden avantajlı olsalar da henüz rutin klinik kullanıma girmeleri için daha fazla veriye ihtiyaç vardır., The survival rate of premature infants has increased dramatically, after the beginning of surfactant use in newborn clinics for premature infants with respiratory distress syndrome. The surfactant delivery methods to the lungs have started to evolve into less invasive and even non-invasive methods over the time. Studies on new methods such as thin catheter surfactant administration, laryngeal or supraglottic airway device, pharyngeal instillation, and aerosolized techniques are increasing. The purpose of the less invasive or noninvasive methods is the protection of immature lungs from harmful effects of intubation, positive pressure ventilation and invasive mechanical ventilation. It has been reported in many studies and meta-analysis that TCA methods were related to lower need of mechanical ventilation, shorter duration of mechanical ventilation, and lower incidence of bronchopulmonary dysplasia or death, compared to intubation, surfactant, and positive pressure ventilation methods. However, there are heterogeneities in premedication policies and respiratory support type, and the type of surfactant applied in the studies. Laryngeal or supraglottic airway device, pharyngeal instillation, and aerosolized techniques have advantages over thin catheter, because they eliminate the disadvantages of laryngoscopy, they are less invasive than thin catheter and they require minimal experience and skills, but more data are needed for routine clinical use of these new methods.

The article discusses the process of formation of deposits in the pipelines of the engine oil system and the factors affecting the conditions for their formation. The technological process of oxidation and the criteria for indicator parameters characterizing the thermolysis of used oil are shown. An extractive method is proposed that ensures the removal of deposits from the pipeline using special flushing process fluids based on regenerated petroleum oil. To search for cheap and efficient hydrocarbon raw materials, regenerated petroleum oils were chosen from among the renewable resources of oil refining. The proposed process fluid was prepared on the basis of low-viscosity spent and then purified petroleum oil. The viscosity of the petroleum oil was adjusted with the addition of petroleum kerosene or diesel. Diluted surfactant solutions were used as additives. and detergent additive (alkali metal salts). It was revealed that in the oil system of an automobile engine at high temperatures (200-3500C) oil thermolysis occurs, and the resulting deposits contain asphaltenes, carbons and carboids. The efficiency of dissolution of deposits in the mixture under study at low temperatures and the concentration of surfactants were revealed. The dependence of the interfacial tension on the concentration of various surfactants is shown. The limiting amounts of the content of the constituent components are found and the ratio of oily extract, from deposits of oxidized oil, is selected. As a result of the tests, it was found that the washing liquid reduces the interfacial tension between the surface of the pipes and deposits and leads to an increase in the movement of the liquid. It has been established that the process of washing off deposits depends on the composition of the deposits, as well as on the composition of the oily extract. The optimal mode and prescription composition of the flushing liquid has been selected. The efficiency of washing off the studied liquid with other means is shown, while it should be noted that this liquid has a simple component composition and is much cheaper than other means.

The traditional extraction methods used to recover natural antioxidants from food industry wastes involve significant amounts of hazardous solvents. A viable alternative is the use of non-toxic surfactants to remove organic compounds from wastes at temperatures above the cloud point. Cloud point extraction has only recently begun to be used to recover high-value added compounds from food industry wastes. In the current work, a method for the isolation of high-value added components from liquid tomato wastewater using a cloud point extraction method was developed and optimized. Food-grade lecithin was examined for its potential to be used as a surfactant in the developed procedure. Moreover, parameters affecting the extraction (ionic strength, sample pH, temperature of extraction, and surfactant concentration) were examined and optimized. According to the results, the maximum recovery of carotenoids from the sample could be achieved with the developed procedure, by simply adjusting the pH to 3.5, adding 35.6% (w/v) sodium chloride, and setting the temperature at 45 °C. Moreover, the amount of lecithin used was examined. In order to extract the total amount of carotenoids from a sample, it was found that either three extractions with 1% lecithin are needed, or two extractions with 2% lecithin. In addition, the antioxidant activity of the extract was examined and it was found to scavenge 36.3% of DPPH free radicals. This percentage was 10% lower compared to the initial sample, which suggests that the extracted compounds retain their activity. Overall, the developed procedure can be used to recover carotenoids in a cost-efficient and easy way.

HYPOTHESIS: Predicting the surface tension (SFT)-log(c) profiles of hydrocarbon surfactants in aqueous solution is computationally non-trivial, and empirically challenging due to the diverse and complex architecture and interactions of surfactant molecules. Machine learning (ML), combining a data-based and knowledge-based approach, can provide a powerful means to relate molecular descriptors to SFT profiles. EXPERIMENTS: A dataset of SFT for 154 model hydrocarbon surfactants at 20-30 °C is fitted to the Szyszkowski equation to extract three characteristic parameters (Γmax,KL and critical micelle concentration (CMC)) which are correlated to a series of 2D and 3D molecular descriptors. Key (∼10) descriptors were selected by removing co-correlation, and employing a gradient-boosted regressor model to rank feature importance and carry out recursive feature elimination (RFE). The hyperparameters of each target-variable model were fine-tuned using a randomised cross-validated grid search, to improve predictive ability and reduce overfitting. FINDINGS: The ML models correlate favourably with test experimental data, with R2= 0.69-0.87, and the merits and limitations of the approach are discussed based on 'unseen' hydrocarbon surfactants. The incorporation of a knowledge-based framework provides an appropriate smoothing of the experimental data which simplifies the data-driven approach and enhances its generality. Open-source codes and a brief tutorial are provided.

In particular, this study aims to investigate the effect of aluminosilicate nanoparticle in the mixture of anionic (Sulfonated Alkyl Ester) and nonionic (Fatty Ester Oleate) surfactants on the interfacial tension and wettability related to EOR processes. Various experiments were conducted such as measuring interfacial tension between oil and brine using spinning drop tensiometer, measuring contact angle between surfactant-NPs-brine solution and Buff Berea core using optical tensiometer, conducting spontaneous imbibition, and core flooding tests.It is observed that the more anionic surfactant in the mixture the more significant aluminosilicate reduces contact angle and increases interfacial tension (IFT), which promotes contradicting effect on oil recovery. In this study, the IFT prevails and eventually reduces ultimate oil recovery. At spontaneous imbibition tests the ultimate oil recovery is decreased from 58% to 47% and from 63% to 46% for SAE-01A and SAE-01B, respectively. The ultimate oil recovery is reduced from 54% to 35% and from 50% to 39% at core flooding tests (Figure 16) for SAE-01A and SAE-01B, respectively. The aluminosilicate nanoparticle contributes positively as the ratio of SAE and FEO becomes smaller. At surfactant formulation ratio of 1:2 (SAE-01C), the IFT is decreased slightly from 4.36 x 10−3 mN/m to 2.36 x 10−3 mN/m and contact angle is also slightly reduced from 41.9° to 40.3° by adding 250 ppm NPs. The results show that ultimate oil recovery is increased 52% to 61% and from 47% to 49% at spontaneous imbibition tests and core flooding tests, respectively.

Due to the continuous depletion of crude oils in the reserves, and continuous rise in energy demand, there is currently a widespread interest in various methods of chemical enhanced oil recovery (EOR). Surfactants flooding improves oil recovery by combining various mechanisms and this approach has proven to be effective. Surfactant flooding is still threatened by problems which are unstable under excessive adsorption and harsh reservoir conditions. Research has shown that anionic surfactant is most preferred for EOR specifically with sandstone reservoirs. In some cases, after injecting non-ionic, cationic, or both surfactants, into the carbonate reservoirs, better performance has been documented. To produce surfactants for reservoirs with properties such as high/ultra-high temperature, ultra/high oil viscosity, ultra-high salinity, and low/extra-low permeability, new knowledge is needed. An ideal surfactant with highest recovery should possess larger IFT reduction, wettability alteration, and asphaltene inhibition capabilities. This review provides an experimental study on surfactant application to conventional and unconventional reservoirs for EOR. Thus, establishing a good foundation for preparing and designing prospective field-scale chemical supported EOR systems. Furthermore, this study presents the influence of oilfield element variation during surfactant flooding, types and EOR mechanisms, its application in unconventional reservoirs, surfactant adsorption and adsorption mitigation, surfactant phase behavior etc.

The hydrodynamics of thin films is an important factor when it comes to the stability and rheology of multiphasic materials, such as foams, emulsions, and polymer blends. However, there have so far been only limited experimental studies addressing the dynamics of individual free-standing thin films at conditions similar to those encountered on macroscopic scales. In this article, we study a well-characterized system of a water-in-oil emulsion stabilized by a non-ionic surfactant (SPAN80) close to its CMC. We employ a dynamic thin film balance, to study the dynamics of freestanding films under both constant and time-varied pressure drops. We compare with the recently published results of Narayan et al. (2020) on colliding droplets of the same system with a hydrodynamic microfluidic trap, and show for the first time that agreement between the two lengthscales is possible, which indicates that the coalescence is indeed dominated by the dynamics in the film. We then address the scatter in the coalescence times and show that it can be affected by extrinsic factors, as well as by variations in the collision angle. Finally, we discuss the difficulties of extracting insight on the coalescence mechanism from coalescence time distributions when different effects such as impurities, small pressure variations, collision angle variations, and possible Marangoni-related instabilities are at play., Rheologica Acta, 61 (10), ISSN:0035-4511, ISSN:1435-1528

The assembly of colloidal hyaluronic acid (HyA, as a polysaccharide) based hydrogel particles in an aqueous medium is characterized in the present paper, with an emphasis on the particular case of nanohydrogels formed by surfactant-neutralized polysaccharide networks. The structural changes and particle formation process of polysaccharide- and cationic-surfactant-containing systems were induced by the charge neutralization ability and the hydrophobic interactions of cetyltrimethylammonium bromide (CTAB) under different conditions. Based on the rheological, light scattering, ζ-potential, turbidity, and charge titration measurements, it can be concluded that the preparation of the HyA-CTAB particles can be greatly controlled. The results indicate that more available negative charges can be detected on the polymer chain at smaller initial amounts of HyA (cHyA < 0.10 mg/mL), where a molecular solution can be formed. The change in the pH has a negligible effect on the formation process (particle aggregation appears at nCTAB/nHyA,monomer~1.0 in every case), while the temperature dependence of the critical micelle concentration (c.m.c.) of CTAB determines the complete neutralization of the forming nanohydrogels. The results of our measurements confirm that after the appearance of stable colloidal particles, a structural change and aggregation of the polymer particles take place, and finally the complete charge neutralization of the system occurs.

The adsorption of hexylamine at the solution–gold interface in 1 M HClO4 in the presence of 0.1 M Fe2+ and 0.1 Fe3+ was studied by potentiodynamic, chronoamperometric and EIS methods. The main kinetic characteristics of the oxidation-reduction reaction iron ions (exchange current density, transfer coefficient, diffusion coefficients of iron ions) were determined. It was shown that the physical adsorption of hexylamine on gold can be described by the Dhar–Flory–Huggins isotherm. The values of the adsorption constant and the Gibbs free adsorption energy were obtained. A comparison of the free adsorption energy at these interfaces with the interaction energies of hexylamine and water molecules, and hexylamine molecules with each other was carried out. It was shown that hexylamine adsorption at all of these interfaces is due mainly to the hydrophobic effect of the interaction of hexylamine and water molecules.

This thesis presents the investigation of the multilevel assembly of the alkyl oligoethylenoxide carboxylic acids and cyclodextrins. The aim of the work is to combine the short-range host-guest and long-range electrostatic interactions to form highly-ordered supramolecular complexes. The interactions between the components affect their individual response and their properties; therefore, the knowledge of the nature and the influence of their chemical structure is essential to understand the system’s behaviour. Polyoxyethylene alkyl carboxylic acids are an attractive class of surfactants to integrate both inclusion complexes and polyelectrolyte systems due to their pH and thermoresponsiveness. The complementary combination approach of thermodynamic and structural investigations allowed probing the formation and responsiveness of the complexes. First, the inclusion complexes systems were studied by densitometry and isothermal titration calorimetry and a comprehensive structural investigation was conducted by small-angle neutron scattering, differential scanning calorimetry and microscopy. The spontaneous formation of the host-guest complexes at different pH was evidenced, and their assembly as building blocks of large supramolecular aggregates with rich structural behaviour was verified. Different aspects of these systems were studied, and it was possible to tune the structures by exploring the components’ concentration, cyclodextrin-to-surfactant ratio, and the pH response of the surfactants. The charge density plays an important role in directing the assembly into highlyordered cylindrical structures without drastically changing the thermodynamics of the inclusion complex formation. In addition, the analysis allowed to unveil the effect of the temperature, the chemical structure of the surfactants and the cyclodextrin on the morphology of the aggregates. Finally, the co-assembly between inclusion complexes and chitosan exploring the long-range electrostatic interactions was assessed in different aspects with a main focus on their structures and directing their assembly by controlling the pH and concentration of the systems. This thesis delivers a thermodynamic and structural complementary approach that allows designing supramolecular aggregates of the desired properties with potential applications in a variety of formulations. It also highlights the importance of evaluating the impact of the tuning parameters in the hierarchical assembly process from the short to the long-range interactions envisioning their systematic application.

Technological advancement, on the one hand, leads to the enhanced quality of the final product but on the other hand, generates a good quantity of effluent. The wastewater containing dyes which emanates from the textile industry is a cause of worry. Hence, this paper focuses on the treatment of dyeing wastewater using the foam separation process as it offers several advantages over other traditional methods. Methylene blue (MB), owing to its ill effects on the entire ecosystem, has been considered as a model dye in this research work. The objective of this work is to remove MB from wastewater and at the same time, its recovery in the foam phase. The ability of sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) to perform separation of MB was compared. The following operating parameters were identified: contact time, initial pH of a feed solution, surfactant dose, volumetric flow rate of air, volume of liquid in the column, and concentration of dye; which greatly influence the separation parameters (% removal and enrichment ratio). Keeping in mind the importance of recovering MB from dilute solutions, the method to enhance foam drainage was devised by inserting an inverted funnel in the foam phase. In the presence of inverted funnel, the concentration of MB in the foamate doubled in comparison to the conventional column (without an inverted funnel). The comparison between SDS and SDBS divulged SDBS as a better surfactant to get concentrated solution of MB in the foamate, but the quantity of SDBS required was more. The optimization of operating variables was also done by using the Taguchi method and Grey relational analysis. Finally, the concentration of MB was discovered to be the most responsive operating parameter for both separation parameters.

Electrochemical impedance spectroscopy (EIS) is a sensitive analytical method for surface and bulk properties. Classical EIS and derived electrochemical capacitance spectroscopy (ECS) with a redox couple are label-free approaches for biosensor development, but doubts arise regarding interpretability when a redox couple is employed (redox EIS) due to interactions between electroactive probes and interfacial charges or forced potential. Here, we demonstrated redoxless ECS for directly determining surfactant adsorption on screen-printed carbon electrodes (SPCEs), validated through a simulation of equivalent circuits and the electrochemistry of electronic dummy cells. Redoxless ECS provides excellent capacitance plot loci for quantifying the interfacial permittivity of di-electric layers on electrode surfaces. Redoxless ECS was compared with redox EIS/ECS, revealing a favorable discrimination of interfacial capacitances under both low and high SDS coverage on SPCEs and demonstrating potential for probeless (reagentless) sensing. Furthermore, the proposed method was applied in an electrolyte without a redox couple and bare electrodes, obtaining a high performance for the adsorption of surfactants Tween-20, Triton-X100, sodium dodecyl sulfate, and tetrapropylammonium bromide. This approach offers a simple and straightforward means for a semi-quantitative evaluation of small molecule interactions with electrode surfaces. Our proposed approach may serve as a starting point for future probeless (reagentless) and label-free biosensors based on electrochemistry, eliminating disturbance with surface charge properties and minimizing forced potential bias by avoiding redox couples. An unambiguous and quantitative determination of physicochemical properties of biochemically recognizable layers will be relevant for biosensor development.

Over the past few decades, better surface quality has remained of great interest to researchers. It deteriorates the fatigue life of the workpiece. The criticality arises when a material of greater strength is selected to work in high-temperature areas such as nickel (Ni)-based superalloys, categorically Inconel 617. Conventional machining operations are not the best choice for the machining of this alloy because of its low density and greater strength. Therefore, electric discharge machining (EDM) is generally engaged. Still, there is a great necessity to make a more reliable surface using EDM, which performs better even in harsh working areas. Therefore, this study examined the potential of deep-cryogenically treated electrodes under the modified dielectrics of transformer oil in the said context, which has not been discussed so far. A set of 30 experiments was performed, designed using the full factorial technique. Deep-cryogenically treated electrodes provided better surface quality in comparison to the non-treated electrodes. Amongst the deep-cryogenically treated electrodes, brass performed outstandingly and provided the lowest value of surface roughness (SR), 6.65 µm, in the modified dielectric of transformer oil with Span 80. The surface finish of deep-cryogenically treated brass is 28.72% better compared to the average value of the overall deep-cryogenically treated electrodes. The lowest value of SR (8.35 µm) was gained by engaging a non-cryogenically treated Cu electrode with a T-20–transformer oil-modified dielectric. The said value of SR is 17.7% better than the highest value of SR achieved in the case of S-80–transformer oil with a non-cryogenically treated Cu electrode.

The excessive presence of single-use plastics is rapidly degrading our natural environment on a global scale due to their inherent resistance to decomposition. Wet wipes used for personal or household purposes contribute significantly to the accumulation of plastic waste. One potential solution to address this problem involves developing eco-friendly materials that possess the ability to degrade naturally while retaining their washing capabilities. For this purpose, the beads from sodium alginate, gellan gum, and a mixture of these natural polymers containing surfactant were produced using the ionotropic gelation method. Stability studies of the beads by observing their appearance and diameter were performed after incubation in solutions of different pH values. The images showed that macroparticles were reduced in size in an acidic medium and swelled in solution of pH-neutral phosphate-buffered saline. Moreover, all the beads first swelled and then degraded in alkaline conditions. The beads based on gellan gum and combining both polymers were the least sensitive to pH changes. The compression tests revealed that the stiffness of all macroparticles decreased with the increasing pH of the solutions in which they were immersed. The studied beads were more rigid in an acidic solution than in alkaline conditions. The biodegradation of macroparticles was assessed using a respirometric method in soil and seawater. It is important to note that the macroparticles degraded more rapidly in soil than in seawater.

The research described here investigated the suitability of coagulation process in the elimination of microplastics from tap water. The purpose of the study was to assess the effects of microplastic type (PE1, PE2, PE3, PVC1, PVC2, and PVC3), tap water pH (3, 5, 7, and 9), coagulant doses (0, 0.025, 0.05, 0.1 and 0.2 g/L), and microplastic concentration (0.05, 0.1, 0.15, and 0.2 g/L) on elimination efficiency with coagulation utilizing Al and Fe coagulants as well coagulation combined with a detergent (SDBS) addition. This work also explores the elimination of a mixture of two microplastics (PE and PVC) that are significant in terms of the environment. The effectiveness of conventional and detergent-assisted coagulation was calculated as a percentage. The fundamental characteristics of microplastics were also determined via LDIR analysis, and on the basis of these findings, particles that were more coagulation-prone were identified. The maximum reduction in MPs was achieved with tap water’s neutral pH and a coagulant dosage of 0.05 g/L. The addition of SDBS increased the loss of the plastic microparticles’ efficacy. A removal efficiency of greater than 95% (Al-coagulant) and 80% (Fe-coagulant) was achieved for each of the microplastics tested. The removal efficiency of the microplastic mixture with SDBS-assisted coagulation was obtained at a level of 95.92% (AlCl3·6H2O) and 98.9% (FeCl3·6H2O). After each coagulation procedure, the mean circularity and solidity of the unremoved particles increased. This confirmed that particles with irregular shapes are easier to completely remove.

V sklopu diplomske naloge smo v prvem delu določali najbolj optimalno formulacijo šampona za lase s sirotko. Kot primarni površinsko aktivni snovi (PAS) smo uporabili natrijev lavrilsulfat (SLS) in za kožo manj dražeči natrijev lavretsulfat (SLES). V prvem koraku smo določali njuno najbolj optimalno koncentracijo. V drugem koraku smo dodajali zgoščevalo (natrijev klorid), nato ugotavljali najbolj optimalno razmerje med sekundarnima PAS, (kokamidopropilbetainom in kokamiddietanolaminom (kokamid DEA)). Naš cilj je bil dodati čim manj kokamid DEA zaradi omejevanja njene uporabe. Na koncu smo šamponom dodajali tekočo sirotko, katere smo želeli dodati čim več, saj ima ugodne učinke tako na kožo, kot tudi na samo formulacijo. Najbolj optimalne šampone s sirotko in brez nje (kontrolni vzorec) smo nato vrednotili s stabilnostnimi testi, in sicer smo jim določali viskoznost (rotacija, amplituda, frekvenca), pH ter organoleptične lastnosti. Šampone smo shranjevali pri sobni temperaturi in v komori s 40 ␃ v času 6 tednov. Vrednotili smo jih ob času 0, po 1 tednu, 2 tednih, 4 tednih in 6 tednih. Ugotovili smo, da so šamponi stabilni, kljub temu da vanje nismo dodali konzervansov. Viskoznost se skozi čas ni spremenila, prav tako organoleptične lastnosti. Pri pH je prišlo v času študije do minimalnega povečanja (0,5 enote), kar označujemo kot nebistveno spremembo in zaključimo, da so šamponi tudi s kemijskega vidika stabilni. Šamponi s sirotko so imeli značilen vonj po sirotki in rahlo rumenkasto obarvanje, kar bi lahko prekrili z dišavami in barvili. As part of the diploma thesis, we first determined the most optimal formulation of hair shampoo with whey. As primary surfactants (PAS), we tested sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES) as a less irritating alternative. In the first step, we determined their most optimal concentration. In the second step, we added a thickener (sodium chloride), and studied the most optimal ratio between the secondary PAS (cocamidopropylbetaine and cocamide diethanolamine (cocamide DEA)). Our goal was to add the minimal concentration of DEA, since its use is limited. In the end, we added liquid whey to the shampoos, where we wanted to add the highest concentration possible, as it has beneficial effects both on the skin and on the formulation itself. The most optimal shampoos with and without whey (as a control) were then evaluated with stability tests, in which viscosity (rotation, amplitude and frequency sweep), pH and organoleptic properties were determined. The shampoos were stored at room temperature and in a thermostatic chamber (40 ␃) for 6 weeks. We evaluated them at time 0, after 1 week, 2 weeks, 4 weeks and 6 weeks. We have found out that shampoos are stable, although no preservatives were added. The viscosity did not change over time, nor did the organoleptic characteristics. There was a slight increase in pH (0.5 units), which can be assessed as insignificant and we can conclude that shampoos are also chemically stable. Whey shampoos had a characteristic whey smell and a slight yellowish color, which could be covered with fragrances and dyes.

In the present work, mathematical models relating mass density and specific volume of solution with concentration for aqueous solutions of anionic (sodium lauryl sulfate - SLS) and cationic (cetyltrimethylammonium bromide - CTAB) surfactants (0-10% (w/w)) have been investigated. The experimental studies were performed to study the effect of solution concentration on mass density and specific volume of solution. Mass density increases, and specific volume decreases with an increase in solution concentration for both surfactants. Linear, quadratic, cubic, quartic, quintic, and exponential models were fitted to the experimental data to check the applicability. The models were validated based on the coefficient of determination (R2) and the sum of square of error (SSE) to be unity and zero, respectively. Modelling results reveal that the quintic model was fitted to study the effect of density on solution concentration for both surfactants. KEY WORDS: Density, Surfactant, Cetyltrimethylammonium bromide, Sodium lauryl sulfate, Modelling, Regression Bull. Chem. Soc. Ethiop. 2023, 37(4), 1047-1054. DOI: https://dx.doi.org/10.4314/bcse.v37i4.19

The thermal conductivity and stability of any nanofluid are essential thermophysical properties. These properties are affected by many parameters, such as the nanoparticles, the base fluid, the surfactant, and the sonication time used for mixing. In this study, multi-walled carbon nanotubes (MWCNTs) were selected as additive particles, and the remaining variables were tested to reach the most suitable nanofluid that can be used to cool photovoltaic/thermal (PVT) systems operating in the harsh summer conditions of the city of Baghdad. Among the tested base fluids, water was chosen, although ethylene glycol (EG), propylene glycol (PG), and heat transfer oil (HTO) were available. The novelty of the current study contains the optimization of nanofluid preparation time to improve MWCNTs’ PVT performance with different surfactants (CTAB, SDS, and SDBS) and base fluids (water, EG, PG, and oil). When 1% MWCNT mass fraction was added, the thermal conductivity (TC) of all tested fluids increased, and the water + nano-MWCNT advanced all TC (EG, PG, and oil) by 119.5%, 308%, and 210%, respectively. The aqueous nanofluids’ stability also exceeded the EG, PG, and oil at the mass fraction of 0.5% MWCNTs by 11.6%, 20.3%, and 16.66%, respectively. A nanofluid consisting of 0.5% MWCNTs, water (base fluid), and CTAB (surfactant) was selected with a sonication time of three and quarter hours, considering that these preparation conditions were practically the best. This fluid was circulated in an installed outdoor, weather-exposed PVT system. Experiments were carried out in the harsh weather conditions of Baghdad, Iraq, to test the effectiveness of the PVT system and the nanofluid. The nanofluid-cooled system achieved an electrical efficiency increase of 88.85% and 44% compared to standalone PV and water-cooled PVT systems, respectively. Additionally, its thermal efficiency was about 20% higher than that of a water-cooled PVT system. With the effect of the high temperature of the PV panel (at noon), the electrical efficiency of the systems was decreased, and the least affected was the nanofluid-cooled PVT system. The thermal efficiency of the nanofluid-cooled PVT system was also increased under these conditions. This success confirms that the prepared nanofluid cooling of the PVT system approach can be used in the severe weather of the city of Baghdad.

The high fluidity and low yield stress of fresh foam concrete affect the shape stability and buildability of foam concrete in the printing process, which is quite a challenge to its application in digital construction. Therefore, this article proposes the preparation and characteristics of 3D printed pre-foaming concrete (3DFC). The rheological properties proved that the addition of 0.1 wt.% Hydroxypropyl methyl cellulose (HPMC) to 3DFCs weakens the fluidity but increases the static yield stress and apparent viscosity, thus enhancing the buildability. More importantly, the influences of surfactant on the rheological property, compressive strength, pore structure and thermal conductivity of 3DFCs were evaluated. Analysis results show that the static yield stress of 3DFCs decreases from 1735 to 687 Pa with surfactant dosage from 0 to 2 wt.%. Moreover, the addition of surfactant significantly reduced the apparent viscosity of 3DFCs (especially at low shear rates), but its viscosity recovery rate was basically unchanged, which is good for buildability. Thanks to the increase of porosity, the volume density of 3DFCs decreased from 2211 to 1159 kg/m3, but the compressive strength of 3DFCs also decreased slightly. The thermal conductivity of 3DFCs shows good thermal insulation performance in the range of 0.2254–0.2879 W/m·K, which is also due to the increase in porosity of 3DFCs. Finally, in order to verify the practical application value of 3DFCs, an industrial printing product with more than 30 layers during the field application is displayed.

[ES] La presente tesis doctoral se centra en la obtención, vía síntesis directa, de materiales zeolíticos nanocristalinos con propiedades fisicoquímicas y catalíticas mejoradas respecto a los materiales de referencia. Para ello se ha hecho uso de tensioativos creados específicamente para cada una de las estructuras zeolíticas estudiadas, evitando el uso de procesos post-sintéticos que conllevan una pérdida de material cristalino. En la primera parte del trabajo se ha estudiado la obtención de la zeolita ITQ-2 deslaminada por síntesis directa (DS-ITQ-2) mediante el uso de varios tensioactivos, siendo el C16DC1 (N-Hexadecil-N'-metil-1,4-diazabiciclo[2.2.2]octano) con el que mejores resultados se han obtenido. Se ha estudiado la influencia de la longitud de la cadena alifática y la concentración del agente director de estructura orgánico (ADEO) en el gel de síntesis sobre la cinética del proceso de cristalización y las implicaciones sobre las características fisicoquímicas del material obtenido. Mediante el control de la concentración del tensioactivo en el gel de síntesis, ha sido posible dirigir el grado de deslaminación del material final. Las propiedades fisicoquímicas del material considerado como óptimo se han comparado con las de las zeolitas MCM-22, MCM-56 e ITQ-2, todas ellas con la misma estructura cristalina (MWW). Por último, la actividad catalítica de la zeolita DS-ITQ-2 se ha estudiado en dos reacciones, la alquilación de benceno con propileno para la obtención de cumeno y la reacción de 2,5-dimetilfurano con etileno para la obtención de p-xileno, obteniendo en ambos casos unos resultados de conversión y selectividad excelentes. La segunda parte de la tesis se ha centrado en la preparación de la zeolita ferrierita en su forma nanocristalina por síntesis directa mediante la utilización de tensioactivos. Se han estudiado tensioactivos con tres partes polares diferentes obtenidos a partir de las correspondientes aminas utilizadas como ADEOs. Además, también se ha estudiado el efecto de la longitud de la cadena del tensioactivo entre los 6 y los 16 átomos de carbono. La modificación de parámetros del gel de síntesis como por ejemplo la relación molar entre la piperidina o el tensioactivo y la sílice ha resultado ser determinante a la hora de conseguir una composición óptima para la obtención de la zeolita nanocristalina con las propiedades fisicoquímicas deseadas. La optimización de la temperatura de síntesis y la introducción de cristales de siembra en el gel de síntesis ha permitido mejorar las propiedades finales del material. La actividad catalítica de las nanoferrieritas se ha estudiado en dos reacciones diferentes, la oligomerización de 1-penteno y la isomerización de 1-buteno. Se ha mostrado la importancia de reducir el tamaño del cristal de la ferrierita, obteniéndose materiales con actividad y selectividad muy superior a los descritos en la bibliografía abierta y de patentes., [CA] La present tesis doctoral es centra en l'obtenció, via síntesi directa, de materials zeolítics nanocristalins amb propietats fisicoquímiques i catalítiques millorades respecte als materiales de referència. Per a això s'ha fet ús de tensioatius creats específicament per a cadascuna de les estructures zeolítiques estudiades, evitant l'ús de processos post-sintètics que comporten una pèrdua de material cristal·lí. En la primera part del treball s'ha estudiat l'obtenció de la zeolita ITQ-2 deslaminada per síntesi directa (DS-ITQ-2) mitjançant l'ús de diversos tensioactius, essent el C16DC1 (N-Hexadecil-N'-metil-1,4-diazabiciclo[2.2.2]octà) amb el que millors resultats s'han obtés. S'ha estudiat la influència de la longitud de la cadena alifàtica i la concentració de l'agent director d'estructura orgànic (ADEO) en el gel de síntesi sobre la cinètica del procés de cristal·lització i les implicacions sobre les característiques fisicoquímiques del material obtés. Mitjançant el control de la concentració del tensioactiu en el gel de síntesi, ha sigut possible dirigir el grau de deslaminació del material final. Les propietats fisicoquímiques del material considerat com òptim s'han comparat amb les de les zeolites MCM-22, MCM-56 i ITQ-2, totes elles amb la mateixa estructura cristal·lina (MWW). Per íltim, l'activitat catalítica de la zeolita DS-ITQ-2 s'ha estudiat en dos reaccions, l'alquilació de benzé amb propilé per a l'obtenció de cumé i la reacció de 2,5-dimetilfurà amb etilé per a l'obtenció de p-xilé, obtenint en tots dos casos uns resultats de conversió i selectivitat excel·lents. La segona part de la tesi s'ha centrat en la preparació de la zeolita ferrierita a la seua forma nanocristal·lina per síntesi directa mitjançant la utilizació de tensioactius. S'han estudiat tensioactius amb tres parts polars diferents obtesos a partir de les corresponents amines utilitzades com a ADEOs. A més a més, també s'ha estudiat l'efecte de la longitud de la cadena del tensioactiu entre els 6 i els 16 àtoms de carboni. La modificació de paràmetres del gel de síntesi com per exemple la relació molar entre la piperidina o el tensioactiu i la sílice ha resultat ser determinant a l'hora de conseguir una composició òptima per a l'obtenció de la zeolita nanocristal·lina amb les propietats fisicoquímiques desitjades. L'optimització de la temperatura de síntesi i la introducció de cristalls de sembra en el gel de síntesi ha permés millorar les propietats finals del material. L'activitat catalítica de les nanoferrierites s'ha estudiat en dos reaccions diferents, l'oligomerizació de l'1-penté i la isomerització de l'1-buté. S'ha mostrat la import`ancia de reduir el tamany del cristall de la ferrierita, obtenint-se materials amb activitat i selectivitat molt superior als descrits en la bibliografia oberta i de patents., [EN] This doctoral thesis focuses on obtaining, via direct synthesis, nanocrystalline zeolite materials with improved physicochemical and catalytic properties compared to reference materials. For this, surfactants created specifically for each of the zeolite structures studied have been used, avoiding the use of post-synthetic processes that lead to a loss of crystalline material. In the first part of the work, the obtaining of the delaminated ITQ-2 zeolite by direct synthesis (DS-ITQ-2) through the use of various surfactants, being C16DC1 (NHexadecyl-N'-methyl-1,4-diazabiciclo[2.2.2]octane) with which the best results have been obtained. The influence of the length of the aliphatic chain and the concentration of the organic structure directing agent (OSDA) in the synthesis gel on the kinetics of the crystallization process and the implications on the physicochemical characteristics of the obtained material have been studied. By controlling the concentration of the surfactant in the synthesis gel, it has been possible to direct the degree of delamination of the final material. The physicochemical properties of the material considered optimal have been compared with those of the zeolite MCM-22, MCM-56 and ITQ-2, all of them with the same crystalline structure (MWW). Finally, the catalytic activity of the zeolite DS-ITQ-2 has been studied in two reactions, the alkylation of benzene with propylene to obtain cumene and the reaction of 2,5-dimethylfuran with ethylene to obtain p-xylene, obtaining excellent conversion and selectivity results in both cases. The second part of the thesis has focused on the preparation of ferrierite zeolite in its nanocrystalline form by direct synthesis using surfactants. Surfactants with three different polar parts, obtained from the corresponding amines used as OSDAs, have been studied. In addition, the effect of the chain length of the surfactant between 6 and 16 carbon atoms has also been studied. Modifying the parameters of the synthesis gel, such as the molar ratio between piperidine or surfactant and silica, has turned out to be decisive when it comes to achieving an optimal composition for obtaining nanocrystalline zeolite with the desired physicochemical properties. The optimization of the synthesis temperature and the introduction of seed crystals in the synthesis gel have allowed to improve the final properties of the material. The catalytic activity of nanoferrierites has been studied in two different reactions, the oligomerization of 1-pentene and the isomerization of 1-butene. The importance of reducing the size of the ferrierite crystal has been shown, obtaining materials with activity and selectivity much higher than those described in the open and patent literature.

In den Versuchsreihen dieser experimentellen Arbeit wurden verschiedene Effekte von Surfactant-Bestandteilen auf differenzierende monozytäre Zellen als Modell für Alveolarmakrophagen untersucht. Hintergrund dieser Arbeit ist die erhöhte Infektanfälligkeit und hohe Inzidenz pulmonaler Infektionen bei Frühgeborenen. Die postnatale Surfactant-Gabe stellt eine therapeutische Option dar, die seit Jahrzehnten zur Therapie des Atemnotsyndroms Frühgeborener in der Neonatologie eingesetzt wird. Daher sollte in der vorliegenden Studie der Einfluss von Surfactant und seinen Bestandteilen auf differenzierende mononukleäre Blutzellen als Modell der Alveolarmakrophagen geprüft werden. Die Untersuchung der Effekte der einzelnen Surfactant-Bestandteile (Phosphatidylcholine sowie einzelne Fettsäuren) und des in der Klinik nach wie vor verwendeten Surfactant-Präparats Curosurf® zum einen auf periphere mononukleäre Blutzellen aus Blut von Erwachsenen und zum anderen auf periphere mononukleäre Blutzellen aus Nabelschnurblut sollte zum einen Aufschluss auf die mögliche Veränderung der Phagozytose-Kapazität bzw. des Phagozytose-Index geben -je nach angewandter Substanz- sowie einen potentiellen Unterschied zwischen den Zellen aus Blut von Erwachsenen und den Zellen aus Nabelschnurblut darlegen. Die Hälfte der Proben wurde mit Polyglobin versetzt, einem polyvalenten Immunglobulin. Zum anderen wurde nach Inkubation mit der jeweiligen Substanz die Expression von verschiedenen Oberflächenmarkern analysiert (CD14, CD86, CD80 und HLA-DR), erneut in einem Ansatz mit mononukleären Zellen aus Erwachsenenblut und in einem weiteren Ansatz mit solchen aus Nabelschnurblut. Die dritte große Versuchsreihe beinhaltete die Analyse der Oberflächenmarker von T-Zellen (CD4, CD28 und CD25) mit und ohne OKT3-Stimulation, einem murinen, monoklonalen CD3-Rezeptor-Antikörper, der die T-Zell-Proliferation stimuliert. Es wurden verschiedene negative immunmodulatorische Effekte von Phosphatidylcholinen und vereinzelt auch von Fettsäuren sowie von Curosurf® nachgewiesen: PC16:016:0 erniedrigt ohne Polyglobin den Phagozytose-Index sowohl bei den Zellen aus dem Blut von Erwachsenen als auch bei den Zellen aus Nabelschnurblut. Unter PC14:0/16:0 wurde dies ebenfalls in der Versuchsreihe mit Blut von Erwachsenen bestätigt, sowie unter PC16:0/14:0 mit Nabelschnurblut. Die Phagozytose-Kapazität wurde unter PC16:0/16:0 und PC14:0/16:0 sowohl bei den Zellen aus Blut von Erwachsenen als auch aus Nabelschnurblut (ohne Polyglobin) reduziert. PC16:0/14:0 erzielte diesen Effekt zudem im Ansatz mit Blut von Erwachsenen und PC16:0/18:1 mit Nabelschnurblut. Mit Polyglobin wurde eine reduzierte Phagozytose-Kapazität unter PC16:0/16:0 und PC14:0/16:0 mit Blut von Erwachsenen und unter Curosurf®, PC16:0/16:0 und PC16:0/14:0 gesehen. Die CD14-Expression der phagozytierenden monozytären Zellen wurde im Erwachsenenblut-Ansatz mit Polyglobin durch PC16:0/16:0 reduziert; im Ansatz mit Nabelschnurblut trat dieser Effekt mit Polyglobin sowohl bei phagozytierenden als auch bei nicht-phagozytierenden monozytären Zellen auf. PC16:0/16:0, ein Hauptbestandteil des natürlichen Surfactant, ist hervorzuheben: unter diesem PC kommt es am häufigsten zu einer Modulation des Phagozytose-Index und der Phagozytose-Kapazität. An zweiter Stelle wurde dieser Effekt bei PC16:0/14:0 und bei PC14:0/16:0 beobachtet. Unter den Fettsäuren kam zu keinem signifikanten Effekt. Um dies zu bestätigen, sind weitere Versuche notwendig. Die Versuchsreihe zur Untersuchung des Phänotyps ergab nur unter PC16:0/14:0 eine Reduktion der CD14-Expression bei Blut von Erwachsenen. Die weiteren Oberflächenmarker HLA-DR, CD86 und CD80+/CD86+ wurden nicht durch die Substanzen beeinflusst. Die Versuchsreihe des Phänotyps der T-Zellen mit und ohne OKT3-Stimulation ergab für den Ansatz mit Zellen aus dem Blut von Erwachsenen mit OKT3 eine Reduktion der CD28-Expression unter Curosurf® und erstmals auch einer Fettsäure, C14:0. Ohne OKT3 wurde dieser Effekt unter PC16:0/14:0 bestätigt. Im Nabelschnurblut-Ansatz wurde eine Reduktion der CD28-Expression mit OKT3 bei CD16:0/14:0, Curosurf®, PC14:0/16:0, C18:1 und C16:0 nachgewiesen. Ohne OKT3 wurde dieser Effekt unter PC16:0/14:0 festgestellt. Unter Curosurf® kam es zudem zu einer Reduktion der CD4-Expression bei Zellen aus Nabelschnurblut mit OKT3-Stimulation. OKT3 scheint die Zellen aus Nabelschnurblut anfälliger für die immunmodulatorischen Effekte der Lipide zu machen. Auf CD4 im Erwachsenenblut-Ansatz sowie auf die CD25+/CD4+-Zellen sowohl bei Blut von Erwachsenen als auch bei Nabelschnurblut wurde kein Effekt der untersuchten Substanzen festgestellt. Die negativen immunmodulatorischen Effekte diverser Phosphatidylcholine und auch der Fettsäuren sollte Gegenstand weiterer Untersuchungen sein. Mit Polyglobin als immunstärkendes Agens konnte ein Teil dieser negativen Effekte wieder aufgehoben zu werden. Insbesondere PC16:0/16:0 scheint eine besondere Rolle in der Hemmung der Phagozytose zu haben, was für die Produktion und therapeutische Gabe von synthetisch hergestelltem Surfactant von großer Bedeutung sein kann.

The spectacular evolution of the urban and industrial sector today poses real environmental challenges of water pollution that requires immediate attention. Surfactants are emerging contaminants that pose a significant problem in wastewater treatment, and their presence causes difficulty in traditional treatment processes. In this context, the present work critically reviews the impacts of surfactants and their toxicity on the environment and human health while presenting the various techniques used in wastewater treatment plants to reduce their effects. Surfactants are removed from wastewater using different techniques, including physical, chemical, biological, and membrane treatment. The choice of the most appropriate technique for wastewater treatment is based on many criteria, such as effluent quality, standards to be respected, investment and operating costs, and environmental footprint. Adsorption and coagulation-flocculation are the most suitable techniques for removing detergents from wastewater due to their effectiveness, ease of use, environmental friendliness, and cost-effectiveness. This work is licensed under a Creative Commons Attribution 4.0 International License.

Objectives: To examine the success rate of less invasive surfactant administration (LISA), to identify early predictive factors for the outcome of LISA and to compare neonatal outcomes between the LISA failure group and the group of infants who were succesfully treated with LISA. Design: A retrospective cohort study. Patients: Infants born at less than 33 weeks of gestation (n=158) and treated with LISA for respiratory distress syndrome. Results: LISA was successful in 86 cases (54.4%), 72 preterm infants (45.6%) needed additional surfactant therapy and/or mechanical ventilation in the first 72 hours. In a multivariate logistic regression analysis, six independent predictors were identified: core temperature at the time of admission (adjusted OR 3.56), suboptimal dose of surfactant (adjusted OR 0.254), elevated CRP (>10 mg/L) at 24 hours of life (adjusted OR 0.28), highest respiratory severity score during the first hour of life or at the time of LISA (adjusted OR 0.463), maternal age (adjusted OR 0.923) and birth weight (adjusted OR 1.003). The ROC curve created by using the identified factors indicates good predictive power with an area under the curve of 0.85. LISA failure was associated with a substantially higher risk of pneumothorax, bronchopulmonary dysplasia, intraventricular hemorrhage, severe retinopathy of prematurity, longer duration of mechanical ventilation and prolonged length of hospital stay. Conclusion: Failure of LISA is relatively frequent event in very preterm infants and is associated with adverse outcomes. Prevention of hypothermia during early stabilization and appropriate dosing of surfactant increase may LISA success rates and improve patient outcome.

Funding Information: The authors are grateful for support from the Engineering and Physical Sciences Research Council in the form of a Strategic Equipment Grant EP/T006412/1 and DTP studentship for funding J D Tinkler’s research work. I. Martín-Fabiani is supported by a UK Research and Innovation Future Leaders Fellowship (MP/T02061X/1). Publisher Copyright: © 2022 American Chemical Society. The effects of particle interactions on the size segregation and assembly of colloidal mixtures during drying were investigated. A cationic surfactant was added to a binary latex/silica colloidal dispersion that has been shown to self-stratify upon drying at room temperature. Atomic force microscopy was used to show that the change in particle interactions due to the presence of surfactants reduced the degree of stratification and, in some cases, suppressed the effect altogether. Colloidal dispersions containing higher surfactant concentrations can undergo a complete morphology change, resulting instead in the formation of armored particles consisting of latex particles coated with smaller silica nanoparticles. To further prove that armored particles are produced and that stratification is suppressed, cross-sectional images were produced with energy-dispersive X-ray spectroscopy and confocal fluorescence microscopy. The growth of armored particles was also measured using dynamic light scattering. To complement this research, Brownian dynamics simulations were used to model the drying. By tuning the particle interactions to make them more attractive, the simulations showed the presence of armored particles, and the size segregation process was hindered. The prevention of segregation also results in enhanced transparency of the colloidal films. Overall, this research proves that there is a link between particle interactions and size segregation in drying colloidal blends and provides a valuable tool to control the assembly of different film architectures using an extremely simple method.

Using DNA staining dyes such as SYBR Green I (SGI) and thioflavin T (ThT) to perform label-free detection of aptamer binding has been performed for a long time for both binding assays and biosensor development. Since these dyes are cationic, they can also adsorb to the wall of reaction vessels leading to unstable signals and even false interpretations of the results. In this work, the stability of the signal was first evaluated using ThT and the classic adenosine aptamer. In a polystyrene microplate, a drop in fluorescence was observed even when non-binding targets or water were added, whereas a more stable signal was achieved in a quartz cuvette. Equilibrating the system can also improve signal stability. In addition, a few polymers and surfactants were also screened, and 0.01% Triton X-100 was found to have the best protection effect against fluorescence signal decrease due to dye adsorption. Three aptamers for Hg2+, adenosine, and cortisol were tested for their sensitivity and signal stability in the absence and presence of Triton X-100. In each case, the sensitivity was similar, whereas the signal stability was better for the surfactant. This study indicates that careful control experiments need to be designed to ensure reliable results and that the reliability can be improved by using Triton X-100 and a long equilibration time.

Resource utilization of SO2 from flue gas is a key challenge for the green development of the smelting industry. Recovery of sulfur resources in the form of elemental sulfur (S0), which has a high market demand and is a current focus in the field of SO2 treatment, can reduce the solid waste from desulfurization. In this study, it was found that Pb as a cathode material had good catalytic activity for the electrochemical reduction of SO2 and good selectivity towards elemental sulfur. However, the cathode suffers from sulfur poisoning. The problem was resolved by introducing surfactant, specifically sodium dodecyl benzene sulfonate (SDBS), which significantly lowered the sulfur content ratio on the surface of the electrode from 31.82% to 2.17%. Through the optimization of electrocatalytic parameters, this method enables efficient conversion of SO2 to S0, achieving a selectivity of 83% at pH = 0.25 and E = −0.8 V (vs. SCE).

We report the synthesis of silver anchored and para toluene sulfonic acid (pTSA) doped polyaniline/molybdenum disulfide nanocomposite (pTSA/Ag-Pani@MoS2) for highly reproducible room temperature detection of ammonia and methanol. Pani@MoS2 was synthesized by in situ polymerization of aniline in the presence of MoS2 nanosheets. The chemical reduction of AgNO3 in the presence of Pani@MoS2 led to the anchoring of Ag to Pani@MoS2 and finally doping with pTSA produced highly conductive pTSA/Ag-Pani@MoS2. Morphological analysis showed Pani-coated MoS2 along with the observation of Ag spheres and tubes well anchored to the surface. Structural characterization by X-ray diffraction and X-ray photon spectroscopy showed peaks corresponding to Pani, MoS2, and Ag. The DC electrical conductivity of annealed Pani was 11.2 and it increased to 14.4 in Pani@MoS2 and finally to 16.1 S/cm with the loading of Ag. The high conductivity of ternary pTSA/Ag-Pani@MoS2 is due to Pani and MoS2 π–π* interactions, conductive Ag, as well as the anionic dopant. The pTSA/Ag-Pani@MoS2 also showed better cyclic and isothermal electrical conductivity retention than Pani and Pani@MoS2, owing to the higher conductivity and stability of its constituents. The ammonia and methanol sensing response of pTSA/Ag-Pani@MoS2 showed better sensitivity and reproducibility than Pani@MoS2 owing to the higher conductivity and surface area of the former. Finally, a sensing mechanism involving chemisorption/desorption and electrical compensation is proposed.

Cerasomes are a promising modification of liposomes with covalent siloxane networks on the surface that provide outstanding morphological stability while maintaining all the useful traits of liposomes. Herein, thin film hydration and ethanol sol injection methods were utilized to produce cerasomes of various composition, which were then evaluated for the purpose of drug delivery. The most promising nanoparticles obtained by the thin film method were studied closely using MTT assay, flow cytometry and fluorescence microscopy on T98G glioblastoma cell line and modified with surfactants to achieve stability and the ability to bypass the blood–brain barrier. An antitumor agent, paclitaxel, was loaded into cerasomes, which increased its potency and demonstrated increased ability to induce apoptosis in T98G glioblastoma cell culture. Cerasomes loaded with fluorescent dye rhodamine B demonstrated significantly increased fluorescence in brain slices of Wistar rats compared to free rhodamine B. Thin film hydration with Tween 80 addition was established as a more reliable and versatile method for cerasome preparation. Cerasomes increased the antitumor action of paclitaxel toward T98G cancer cells by a factor of 36 and were able to deliver rhodamine B over the blood–brain barrier in rats.

Surfactants are functional molecules utilized in various situations. The self-assembling property of surfactants enables several molecular arrangements that can be employed to build up nanometer-sized architectures. This is beneficial in the construction of functional inorganic–organic hybrids holding the merits of both inorganic and organic components. Among several surfactants, bolaamphiphile surfactants with two hydrophilic heads are effective, as they have multiple connecting or coordinating sites in one molecule. Here, a functional polyoxotungstate inorganic anion was successfully hybridized with a bolaamphiphile to form single crystals with anisotropic one-dimensional alignment of polyoxotungstate. Keggin-type metatungstate ([H2W12O40]6−, H2W12) was employed as an inorganic anion, and 1,12-dodecamethylenediammonium (C12N2) derived from 1,12-dodecanediamine was combined as an organic counterpart. A simple and general ion-exchange reaction provided a hybrid crystal consisting of H2W12 and C12N2 (C12N2-H2W12). Single crystal X-ray structure analyses revealed a characteristic honeycomb structure in the C12N2-H2W12 hybrid crystal, which is possibly effective for the emergence of conductivity due to the dissociative protons of C12N2.

This article presents the research process and statistical analysis of the selection of an appropriate type of surfactant to be added to natural ester oil MIDEL eN 1204. The tested parameter was the breakdown voltage. The following surfactants were tested: Triton X, ROKwino l80, and oleic acid. With the obtained results, we can conclude that the surfactants with the best properties, compared to the basic oil sample, have oleic acid, and also that high levels of breakdown voltage characterize a sample of Triton X with a concentration of 2%. Statistical analysis was performed using the MATLAB program.

In recent decades, electronic devices have tended towards miniaturization, which necessitates the development of new cooling systems. Droplet cooling on a heated wall is effectively used in power devices with high heat flux densities. The use of a surfactant leads to an increase in the diameter of the wetted spot and the rate of droplet evaporation. Despite the wide interest and numerous works in this area, there are still unexplored questions regarding the influence of surfactant and wall temperature on convection, of nonisothermality, and of the decrease in the partial pressure of vapor with increasing surfactant concentration. This work experimentally studies the effect on the rate of droplet evaporation of wall temperature in the range 20–90 °C and of the concentration of surfactant in an aqueous solution of sodium lauryl sulfate (SLS) from 0 to 10,000 ppm. It is shown for the first time that an inversion of the evaporation rate related to the droplet diameter occurs with increasing wall temperature. The influence of key factors on the evaporation of a water droplet with SLS changes with temperature. Thus, at a slightly heated wall, the growth of the droplet diameter becomes predominant. At high heat flux, the role of nonisothermality is predominant. To determine the individual influence of the surfactant on the partial pressure of water vapor, experiments on the evaporation of a liquid layer were carried out. The obtained results and simplified estimates may be used to develop existing calculation models, as well as to optimize technologies for cooling highly heated surfaces.

Although nanoparticles (NPs) are known to increase foam stability, foam stabilisation is not observed in all surfactant/NP combinations. The present study evaluates the stability of CO2 foams containing surfactant/NP mixtures with attractive or repulsive electrostatic interactions at the low pH imposed by CO2 in the presence of a high-salinity brine. Three ionic surfactants and two oxide NPs (SiO2 and Al2O3) were used in combinations of similar or opposite charges. Surface tension, viscosity, ζ-potential and hydrodynamic size experiments allowed the analysis of CO2 foam stability based on the impact of surfactant–NP interactions on bulk and interfacial properties. All oppositely charged systems improved the foam half-life; however, a higher NP concentration was required to observe a significant effect when more efficient surfactants were present. Both bulk viscosity and rigidity of the interfacial films drastically increased in these systems, reducing foam drainage. The mixture of SiO2 with a zwitterionic surfactant showed the greatest increase in CO2 foam stability owing to the synergy of these effects, mediated by attractive interactions. This study showed that the use of NPs should be tailored to the surfactant of choice to achieve an interplay of interfacial and rheological properties able to reduce foam drainage in applications involving CO2 foam in brine.

A study was conducted to evaluate the effect of an emulsifier on reduced-energy diets using two fat sources for broilers. The study was designed as a 2 x 3 factorial arrangement of treatments. The first factor was 2 fat sources (poultry fat or beef tallow). The second factor was a basal diet with the recommended energy levels, a diet with a 0.83 MJ/kg of energy reduction, and a diet with an energy reduction and inclusion of 1 g emulsifier/kg of diet. The emulsifier used in this study was composed of soy lecithin and polyethylene glycol ricinoleate. The emulsifier increased apparent metabolizable energy (AME) and apparent metabolizable energy corrected for nitrogen balance (AMEn) in beef tallow diets compared to energy-reduced diets (P

Silica sorbent samples were synthesized at different temperatures using saponins as surfactants in an acidic medium. The textural properties of the sorbent samples were studied by adsorbing benzene vapor onto them. The specific surface area of the sorbents at different temperatures was found to be 854,2 m2/g, while the pore volume ranged from 0,32 to 0,90 cm3/g. The average diameter of the pores was found to be in the range of 0,8-32,1 nm.

Mesoporous silica sorbent samples ordered at 30÷80°С were synthesized using the surfactant rutin using sol-gel technology. Based on the sorption of benzene vapors on sorbents, their texture and sorption properties were studied. According to it, it was determined that the specific surface area (SBET) of the sorbents is 675,6÷514,5 m2/g, and the average diameter of the pores is equal to 5,3÷32,8 nm.

Cardiopulmonary arrest is an occasional occurrence during pregnancy. As soon as maternal arrest is noticed in a woman in the second half of her pregnancy, medical teams should be called for perimortem cesarean (C/S). A 31–week-pregnant female patient was brought to our emergency department by the emergency medical service team with cardiopulmonary resuscitation (CPR) after a traffic accident. The patient, with no pulse or spontaneous breathing, was recognized as exitus. However, CPR was sustained to maintain fetal well-being. Before the arrival of the on-call gynecologist, we as emergency physicians initiated C/S both for fetal well-being and to avoid heighten-ing the risk of fetal mortality and morbidity. The Apgar scores were 0/3/4 and oxygen saturation values were 35/65/75% at 1/5/10 min, respectively. On the postnatal 11th day, the patient did not respond despite the advanced cardiac life support (ACLS) and thus was considered exitus.The ACLS team should be knowledgeable and well-equipped to perform C/S, to do aftercare, to watch for related risks in the infant. In our case, it took 40 min for the fetus to be removed from the mother’s womb, starting from the estimated time of exitus. © 2023, Turkish Association of Trauma and Emergency Surgery. All rights reserved.

This study experimentally investigated the effects of surfactants and water-repelling agents on the hydration process, relative humidity, and mechanical properties of Portland cement pastes. Based on the measurement results, the degree of hydration, degree of saturation, capillary tension of autogenous shrinkage, and magnitude of autogenous shrinkage were simulated using a numerical model. In the numerical model, the elastic and creep components of autogenous shrinkage were calculated separately, and the creep component was simulated based on the solidification theory. The simulation results indicated that adding admixtures led to lower degrees of hydration and saturation. The capillary tension of the pure Portland cement was larger than that of the other mixtures. This can be attributed to several factors, including the smaller surface tension of mixtures with surfactants, larger contact angle of mixtures with water-repelling agents, and a lower degree of hydration of mixtures with both admixtures. Analyses of the simulated and measured results for different mixtures also show that creep plays an indispensable role in autogenous shrinkage. Adding a surfactant and a water-repelling agent can effectively mitigate autogenous shrinkage. However, when an excessive amount of water-repelling agent was added, its influence on the mitigation of autogenous shrinkage was insignificant.

В статье представлена информация об исследовании, проведенном с целью изучения взаимозависимых сдвигов в структурах ответственных за вентиляционно-перфузионные отношения в легких после длительной физической нагрузки. Исследования проводились на белых беспородных крысах-самцах молодого половозрелого возраста 5-10месяцев, массой тела 120,0-140,0 гр. Всего использовано 25 подопытные и 10 контрольные крысы. На основании комплексного анатомического, гистохимического, электронно-гистохимического и ультрамикроскопического исследований, изучены модальные изменения респираторного отдела лёгких при хронической, длительной физической нагрузке. Использовалась статическая программы Microsoft Excel LL XP на персональном компьютере “Sony Vaio” различия в сравниваемых группах считались достоверными при р, Məqalədə uzunmüddətli fiziki yükün təsiri zamanı ağciyərlərin ventilyasiya-perfuziya funksiyasında baş verən dəyişikliklərin öyrənilməsi məqsədilə aparılmış tədqiqat işi haqqında məlumat verilmişdir. Tədqiqat cinsi xətti bəlli olmayan, cinsi yetkinliyə çatmış 5-10 aylıq, kütləsi 120,0-140,0 qr olan ağ erkək laborator siçovulları üzərində aparılmışdır. Cəmi 25 siçovuldan istifadə edilmişdir ki, onlardan da 10-u eyni kontrol qrupunu təşkil etmişdir. Tədqiqat zamanı heyvanlardan alınan ağciyər tikələrinin anatomik, histoloji, elektron-histokimyəvi, ultramikroskopik üsullarla kompleks şəkildə istifadə etməklə ağciyərlərin respirator şöbəsində xroniki uzunmüddətli fiziki yükün təsirindən sonra baş verən dəyişikliklər öyrənilmişdir. Histoloji preparatlar Tesla BS 500 elektron mikroskopu vasitəsilə müşahidə edilmiş, “Sony Vaio” fərdi kompüterində Statistik Microsoft Excel LL XP proqramından istifadə edilməklə müqayisə edilən qrupların göstəriciləri arasında fərqlər araşdırılmışdır. Tədqiqat göstərmişdir ki, uzunmüddətli fiziki yükdən sonra ağciyər alveollarında surfaktantın sintezi və utilizasiyası pozulur, distelektaz sahələrinin sayı artır, hipoventilyasion asidoz baş verir. Uzunmüddətli fiziki yükün təsirindən alveolyar makrofaqların ultrastrukturundakı dəyişikliklər sərbəst makrofaqların sayının, onların osmiofil lövhəciklərinin “uducu” effektinin güclənməsi fonunda artımı müşahidə edilmişdir. Bu, surfaktantın miqdarının və intensivliyinin azalmasına səbəb olur. Uzuznmüddətli fiziki gərginlik rejimi aerohematik baryer və alveol epitelinin strukturlarında, surfaktantın sintezi və utilizasiyasında pozuntulara səbəb olur. Elektrohistokimyəvi reaksiyaların məlumatları aerohematik membran komponentlərinin, surfaktantın sintezi və istifadəsi proseslərinin qeyri-stabilliyini göstərir. Beləliklə, artan fiziki yüklənmə şəraitində tənəffüs hipoksiyasına cavab olaraq sağ mədəcikdə ocaqlı zədələnmələr törənir və kiçik qan dövranında hipertenziya inkişaf edir., The article describes a research study that investigates changes in the ventilation-perfusion function of the lungs due to prolonged physical exertion. The study was conducted on male white laboratory rats aged between 5-10 months and weighing 120.0-140.0 g, with a total of 25 rats used, 10 of which were of the same age group. The study utilized lung tissue of the animals, and anatomical, histological, electronhistochemical, and ultramicroscopic methods were employed to comprehensively investigate the modal changes that occur after exposure to chronic prolonged physical load in the respiratory section of the lungs. During the presentation, a Tesla BS 500 electron microscope was used, and the static Microsoft Excel LL XP program was used on a "Sony Vaio" personal computer. Differences in the compared groups were considered significant (p, Azerbaijan Medical Journal, Выпуск 1 2023, Pages 152-158

Background: Improving and maintaining the skin integrity and health are the most essential targets in long-term care. The aim of this study is to formulate a serum of retinyl palmitate (RP) and vitamin E (VE) as nanoemulsion (NE) for achieving healthy skin. Methods: The solubility of RP and VE was studied in different oils. The NEs were prepared using oil, water, and different surfactant-co-surfactant mixtures, and then the medicated nanoemulsion was prepared by addition of 0.5% RP and VE to the oil phase, and vitamin C as an antioxidant to the aqueous phase with different preservatives. The prepared NE was characterized in terms of particle size, charge, rheology, diffusion, and irritation to the skin. Results and conclusion: The data showed that the highest solubility of both RP and VE was in safflower oil. Tween 20, Ceteareth 20 with ethanol, PEG 200, and cremophor RH40. This combination was able to produce NE with good integrity and acceptable particle size. The prepared formulations gave particle size of 60–70 nm and showed Newtonian flow. Irritation tests on rats showed that the formula was safe to be applied on the skin with no signs of irritation up to 72 hours. A preliminary stability study at room temperature showed good stability up to 6 weeks. In conclusion, RP and VE could be formulated successfully as NE with good stability and physical characteristics.

Chronic venous insufficiency, which affects more than 20% of the world’s population, is caused by venous stasis, leading to a cascade of pathological changes in surrounding tissues at the molecular, cellular, and tissue levels [1]. The aim of the study was to study the morphological features of biopsy specimens of a healing ischemic skin defect in mice on the 19th day after transplantation of a tissue-engineered construct from pulmonary surfactant and dermal fibroblasts. 16 white laboratory mice of the C57/B1 line, which had reached the age of 4–6 months, were divided into control and experimental groups. In all groups, an operation to simulate a skin ischemic wound in the scapular region was performed after intraperitoneal injection of a 2.5% solution of Avertin 0.3-0.4 ml, and during the operation, mice of the experimental group were transplanted with a 2D construct consisting of a superficially applied pulmonary surfactant, and the edges and the bottom of the wound was chipped with 0.4 ml of a suspension of allofibroblasts in the growth medium DMEM F12 (Lonza) in the amount of 1.33 million cells. A tissue-engineered construct based on pulmonary surfactant and dermal heterofibroblasts accelerates the healing of an ischemic skin defect. On the 19th day after the wound modeling, the epidermis of the wound biopsy specimens is 2 times thicker and more differentiated compared to the control. In the experimental group, the laying of derivatives of the epidermis - hairs is observed. The granulation tissue is at the beginning of the fibrosis stage, when the area of collagen fibers is 20.20±0.01% larger, and the area of blood vessels is 19.13±0.01% less compared to the control group, where the granulation tissue demonstrates morphological signs of the second stages of the wound process - the stage of proliferation.

Producción Científica, To recover industrial pectin from sugar beet pulp (SBP), a combined surfactant and ultrasound-assisted extrac- tion, followed by a concentration with ultrafiltration/diafiltration membranes is proposed. First, the operation conditions of the extraction were optimized for synthetic (Tween80, PEG4000) and natural (Saponin) surfac- tants. Tween 80 and Saponin provided maximum galacturonic acid (GalA) concentrations (5.5 and 5.8 g/L, respectively) under the best extraction conditions (4 gsurfactant/L, pH = 1, amplitude = 90%, and time = 90 min). The extracted liquid was purified and concentrated through membranes. The final retentate maintained 73% of the initial GalA and eliminated a high percentage of oligosaccharides. Finally, the pectin was precipitated with ethanol, and the precipitate solid contained 57 g GalA/100 g GalA of SBP with a high degree of esterification (DE = 81%) and MW (930 kDa). The pectin yield for the global process was 24.6%. The ultrasound-assisted extraction with surfactants followed by diafiltration/ultrafiltration could become a promising process for the chemical industry, able to provide pectin-enriched products of commercial interest from sugar beet pulp., Ministerio de Ciencia e Innovación (Proyecto PID2020–115110RB-I00/ AEI/10.13039/501100011033), Junta de Castilla y León (UIC 320, VAG028G19, CLU-2017–09, CL-EI-2021–07), Junta de Castilla y Leon (postdoctoral grant E-47–2019-0114592)

Effects of surfactants on lift coefficients, CL, of single ellipsoidal bubbles rising through linear shear flows were investigated. Two types of surface-active agents, Triton X-100 and 1-octanol, were used. The liquid properties except for the surface tension were identical to those in a clean system of logM = -5.5, where M is the Morton number. The range of the bubble Reynolds number was 0.1 < Re < 70. Bubble shapes were either spherical or ellipsoidal. Comparing with clean bubbles, less deformation of contaminated bubbles was confirmed. A shape correlation without taking the dimensionless shear rate into account gave good evaluations of the bubble aspect ratio, which means that the shear rate is not a dominant factor causing the change of shape deformation. However, drag coefficients were affected by the shear rate. A new correlation of drag coefficients was deduced, which agreed well with the experimental data. Both clean and contaminated CL data showed a similar tendency: after a drastic decrease in CL, CL slightly increases and then decreases to a negative value while increasing the bubble Reynolds number, Re. A difference in concentration of Trion X-100 resulted in only a slight change in CL at high Re regime. Different types of surfactant resulted in noticeably different values of CL especially at low Re. The CL of small bubbles in contaminated systems could be reproduced by a correlation for solid particles, supporting that fully contaminated spherical bubbles behave like solid spheres. For deformed bubbles, CL can be expressed by relating the negative lift force due to shape deformation with the drag force.

Cotton woven fabrics functionalized with aqueous inks made with carbon nanofibers (CNFs) and anionic surfactant are prepared via dip-coating followed by heat treatment, and their electronic properties are discussed. The e-textiles prepared with the inks made with the highest amount of CNFs (6.4 mg mL−1 ) show electrical conductivities (σ) of ∼35 S m−1 and a negative Seebeck (S) of −6 μV K−1 at 30 °C, which means that their majority carriers are electrons. The σ(T) of the e-textiles from 30 to 100 °C shows a negative temperature effect, interpreted as a thermally activated hopping mechanism across a random network of potential wells by means of the 3D variable range hopping (VRH) model. Likewise, their S(T) from 30 to 100 °C shows a negative temperature effect, conveniently depicted by the same model proposed for describing the negative Seebeck of doped multiwall carbon nanotube mats. From this model, it is deduced that the cause of the negative Seebeck in the e-textiles may arise from the contribution of the impurities found in the as-received CNFs, which cause sharply varying and localized states at approximately 0.085 eV above their Fermi energy level (EF). Moreover, the possibility of a slight n-doping from the cellulose fibers of the fabrics and the residuals of the anionic surfactant onto the most external CNF graphitic shells present in the e-textiles is also discussed with the help of the σ(T) and S(T) analysis., This research was funded by the project UID/CTM/00264/2021 of 2C2T under the COMPETE and FCT/MCTES (PIDDAC) cofinanced by FEDER through the PT2020 program. E.M. acknowledges financial support from ANID Anillo ACT/192023 and Fondecyt No 1190361.