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I hardly need to talk about that. how important is the timely and rapid recognition of infectious diseases such as relapsing fever and malaria. Since the causative agents of these diseases in a certain period of the disease are in the peripheral blood, the usual method of recognizing these diseases is a blood test.

The article indicates the features of the use of aqueous solutions of surfactants in gas and oil production. The defining parameters of such solutions which are investigated at a choice of the applied surfactants are specified. The analysis of the known methods for determining the interfacial tension by the rotating drop method showed the possibility of improving the procedure for calculating the interfacial tension to simplify it. In the article it is offered to improve a technique of calculation of an interfacial tension by a method of a fixed rotating drop with application of the equation of Vonnegut with a correction factor. The value of the correction factor was obtained from the calculations of the contours of the fixed rotating drops, as well as the calculation of the interfacial tension using the Vonnegut formula based on the calculated contours. It is established that the correction factor can be represented as a functional dependence on the ratio of diameter to the length of the rotating drop. To verify this relationship, the correlation coefficients between the correction factor and the size of the rotating drop were calculated. During the experimental test, the possibility of using the developed technique to study the parameters of aqueous solutions of surfactants with petroleum products was confirmed.

As the main components of synthetic hydrocarbons obtained using gas to liquid conversion technologies, long-chain alkanes and alcohols play an important role in the Fischer–Tropsch process. So the ...

The effects of temperature and pressure on interfacial tension (IFT) of a CO2/n-pentane binary system were investigated using the pendant drop method. To ensure the accuracy and reproducibility of ...

The buoyant drop method is a ubiquitous tool for addressing phenomena at the liquid-liquid interface via the determination of the interfacial tension (IFT) between two immiscible phases. Here, the focus is on how electrolytes (in an aqueous phase) and carboxylic acids (in a decane phase) impact the interfacial layer between the two phases. The IFT measurement provides a single number, which is not fulfilling when it comes to deducing information about a complex multiparameter system. Furthermore, the temporal evolution of IFT does not always reach a steady-state value on a time scale, which is realistic to use for comparative studies. We have investigated the temporal evolution of IFT in a series of experiments with varying compositions of the decane-carboxylic acid phase and the brine phase. The results show that there are at least two opposing effects in play. For water-soluble acids, the IFT initially increases with time until a turnover point is reached from where there is a gradual decay. The IFT at the turnover point is close to that of the pure water-decane system. For a poorly water-soluble acid, the IFT shows a much smaller increase and the turnover happens much faster. For a water-soluble acid, there is a high degree of sensitivity toward the electrolyte; it determines the position (in time) of the IFT peak and the steepness of the subsequent decay. Now, if the phases are reversed, that is, by placing a drop of brine in the decane-surfactant phase, the IFT decreases with time regardless of the acid and with little impact of the electrolyte and its concentration in the brine. We propose an explanation for the observed behavior (supported by COSMO-RS calculations), which is based on diffusion in and out of the two phases, solubility, and interfacial reactivity (i.e., aggregation between electrolytes and carboxylic acids).

Pendant drop method is employed to investigate interfacial tension, bond number, and swelling behavior of crude oil in the presence of brine solutions comprised of MgSO4 and its solution saturated ...

The surface tension of blood plays an important role not only in the birth and decompression sickness but also in other functionality of the organism. It also provides capillary action during blood flow process. In this article, a simple and low-cost device is designed and fabricated for measuring the surface tension of blood by pendant drop method. In this device, a droplet of blood is formed in a closed chamber on tip of an 18-gauge blunt needle and it is photographed by a camera in very humid conditions (RH = 99%) to minimise the evaporation. A wetted wick is provided at the bottom of the chamber for maintaining constant relative humidity in chamber. Surface tension of blood is inferred using drop shape factor method and image analysis technique at various experimental conditions. This device is validated and calibrated with surface tension measurements of water and silicone oil. Its measurements are in good agreement against data reported in literature. Post-validation, surface tensions of blood samples with and without anticoagulant of healthy persons at various temperatures (range from 20 to 40 °C) was measured. It was found that the surface tension of normal blood samples strongly correlates with blood temperature. The surface tension of female blood was remarkably different from same of male blood. However, the effect of age (21-60 year) on the surface tension was negligible for all practical purposes. Increased percentage of anticoagulant in blood increases its surface tension. This research specifies a baseline for surface tension of normal blood samples at various conditions which in turn provides new insights to pathologists in identifying various disease conditions.

A study was carried out on aspects of phenomena on the interfacial boundary of acids and hydrocarbon systems of different complexity. These phenomena were evaluated relative to the interfacial tension measured by the pendant drop method. We discovered peculiarities of the interaction of hydrochloric and sulfamic acids with individual hydrocarbons as well as complex hydrocarbon systems. The complex dependence of the interfacial tension on the composition and properties of the hydrocarbon phase, type and concentration of the acid, and the chemical composition of asphaltenes was elucidated.

The dynamic pendant drop method was employed to better understand the adsorption kinetics at the oil/water interface. Various volume ratios of n-heptane/toluene (heptol) have been chosen as solvent...

The contribution of non-linear fluid flow effects to the damping of surface oscillations in the oscillation drop method was investigated in a series of experiments in an electromagnetic levitation device installed on the International Space station, ISS-EML. In order to correctly evaluate the damping time constant from measured surface oscillation decays the effect of a modulated signal response on measured surface oscillation decay curves was investigated. It could be shown that various experimentally observed signal patterns could be well represented by a modulated response. The physical origin of such modulations is seen in rotation and precession. Over a temperature range of 220 K covered by different surface oscillation excitation pulses with an initial sample shape deformation of 5 – 10% the amplitude of surface oscillations as a function of time could be very well represented by a Lamb type damping with a temperature dependent viscosity. A direct comparison of surface oscillation decay times measured in the same temperature range but for different oscillation amplitudes showed no non-linear contribution to the damping time constant with a confidence level better 10%.

High-throughput measurement of cells perturbed using libraries of small molecules, gene knockouts, or different microenvironmental factors is a key step in functional genomics and pre-clinical drug discovery. However, it remains difficult to perform accurate single-cell assays in 384-well plates, limiting many studies to well-average measurements (e.g. CellTiter-Glo®). Here we describe a public domain “Dye Drop” method that uses sequential density displacement and microscopy to perform multi-step assays on living cells. We use Dye Drop cell viability and DNA replication assays followed by immunofluorescence imaging to collect single-cell dose-response data for 67 investigational and clinical-grade small molecules in 58 breast cancer cell lines. By separating the cytostatic and cytotoxic effects of drugs computationally, we uncover unexpected relationships between the two. Dye Drop is rapid, reproducible, customizable, and compatible with manual or automated laboratory equipment. Dye Drop improves the tradeoff between data content and cost, enabling the collection of information-rich perturbagen-response datasets.

The aim of this study was to evaluate the development, yield and its components of soybean sown in hill drop method with variation in hole spacing, compared to the conventional sowing method in lines. The experiment was conducted in a randomized block design, with six treatments and four replications, using the variety M7739 RR IPRO with four plans per hole. The treatments consisted of population variation from 50 to 150% of the recommended one, obtained by the holes spacing alteration and a control sowed in lines with the recommended population. The control was compared to the other treatments using the Dunnett test and the hole spacing effect was evaluated by regression. The cultivar 7739 RR IPRO responds to hill drop sowing, obtaining even in lower populations, yields similar to the conventional sowing in lines. The highest yields in the hill drop sowing method are obtained in the higher populations, with a linear decrease in yield with an increase in hole spacing. Increasing hole spacing increases the number of pods and branches and reduces leaf cover, light interceptcion, plant height and first pod height.

Postharvest damage, leading to loss and waste, continues to be a significant problem in the fresh produce industry. Trays, designed to reduce fruit-to-fruit contact, are utilized by the apple industry to minimize bruising of whole apples. During distribution, packaged apples are subjected to various supply chain hazards, which may lead to bruising damage. Currently, molded fiber (MF) and expanded polystyrene (EPS) trays transport whole apples from the packhouse to the retail outlet. Mechanical shock, by free-fall drop method, was used to evaluate the performance differences between the two trays and quantify the bruising characteristics of the apples. Results showed that the EPS trays provided better shock protection to the apple as compared to the MF tray, reducing the impact acceleration by more than 70%. Additionally, the bruise susceptibility was 40% less for the apples packaged inside the EPS trays, regardless of drop height. However, apples packaged in the middle layer trays were most susceptible to bruising damage, regardless of tray type.

The article characterizes the impact test method using Drop-Tower Impact Test with the registration of the value of force and energy of breaking. Based on sources, the possibilities and scope of the current application of this method were determined and the current state of knowledge on the results of these tests was reviewed. In order to determine the possibility of using the method in impact tests of high strength steel joints, investigations of hybrid PTA - GMA welding conditions on impact strength of joints of MART S1300QL steel were carried out. In particular, the influence of t8/5 cooling time on the impact strength of welded joints by the Drop - Tower Impact Test method was determined. It has been shown that the use of dropping machine with computer-based registration of breaking force and energy values was possible in the case of impact strength testing of UHSS welded joints and enabled precise analysis of the energy distribution dynamics absorbed by the tested.

Bi–Sn alloy phase diagram under pressure was re-calculated using the CALculation of PHAse Diagrams method by applying new density data. Theoretically, alloy phase diagram under pressure can be calculated with bulk thermodynamic database and thermophysical property data such as density and sonic velocity. In the recent study by Emuna et al. (J Alloys Compd 687:360–369, 2016), thermodynamic parameters were determined from literature values with additional modification to fit experimental data of phase boundaries. In this study, density of liquid Bi–Sn alloys was re-evaluated with an advanced density measurement technique: the constrained drop method. By applying the new density data, the Bi–Sn phase diagram under pressure could be calculated successfully without any modification of thermodynamic parameters.

The hanging-drop method has been widely used to fabricate three-dimensional (3D) in vitro tissue models due to its advantages such as being easy to perform, inexpensive, and permitting precise control of cell spheroid formation. The geometry of hanging drop may play a critical role on the formation of cell spheroids, which, however, has not been explored. In this study, we developed a modified hanging-drop platform that enables the production of cell spheroids in a high-throughput manner by controlling hanging drop geometry with a defined spreading ring. The surface tension force is proportional to the spreading ring and the gravitational force is determined by droplet volume, and the geometry can be determined by the balance between surface tension and gravity. β-TC-6 cell spheroids with optimized diameters were fabricated as 3D in vitro islet models. The models showed morphology similar to primary islets and had functionality that more closely resembled primary islets than two-dimensional cell culture. The developed platform holds great potential for engineering well-controlled in vitro tissue models for various applications such as physiological and pathological studies, drug screening, as well as transplantation for treatment purpose.

A correction to this paper has been published: https://doi.org/10.1007/s10765-021-02870-5

The use of 3D cell culture has been a major step in developing cellular models that can mimic physiological tissues. Traditional 2D cell cultures are often unable to accurately represent the cellular functions and responses that are present in tissues, as a result, research findings based on 2D cultures tend to be skewed with limited predictive capability. 3D cell cultures can be grown from cells obtained from cancer organoids in patients. These models are useful for understanding disease mechanisms and exploring drug therapeutics in areas such as toxicity and efficacy. In order to gather more physiologically relevant data, a variety of 3D cell culture techniques have been developed to mimic the in vivo characteristics of physiological tissues. This protocol describes in vitro generation of U-251MG spheroids using the hanging drop method. Advantages of using hanging drop plate method are, able to produce uniform size spheroids, low cost, comfortable to handling and suitable for short term culture. The main downside of this method is medium change, different drug treatment at different time points are impossible and labor intensive. This method uses the Perfecta3D hanging drop plate, a novel cell culture device that simplifies the process of spheroid formation, testing and analysis. Rather than having to invert the plates which often results in spillage or detachment, these plates are designed to create hanging drops using a plateau structure at the bottom of the plate. We used HDP1096 Perfecta3D® 96-well hanging drop plates for tumorsphere construction from 3D Biomatrix and adapted protocols published by: Hikage, F., Atkins, S., Kahana, A., Smith, T. and Chun, T., 2019. HIF2A–LOX Pathway Promotes Fibrotic Tissue Remodeling in Thyroid-Associated Orbitopathy. Endocrinology, [online] 160(1), p.3. Available at: . Moraes, G., Wink, M., Klamt, F., Silva, A. and Fernandes, M., 2020. Simplified low-cost methodology to establish, histologically process and analyze three-dimensional cancer cell spheroid arrays. European Journal of Cell Biology, [online] 99(5), pp.2-3. Available at: . sigmaaldrich.com. n.d. HDP1096 Perfecta3D® 96-Well Hanging Drop Plates Protocol. [online] Available at: .

W360 is a hot work tool steel produced by voestalpine BÖHLER Edelstahl GmbH & Co KG, a special steel producer located in Styria, Austria. Surface tension and density of liquid W360 were studied as a function of temperature in a non-contact, containerless fashion using the oscillating drop method inside an electromagnetic levitation setup. For both, surface tension and density, a linear model was adapted to present the temperature dependence of these measures, including values for the uncertainties of the fit parameters found. The data obtained are compared to pure iron (with 91 wt% the main component of W360), showing an overlap for the liquid density while there is a significant difference in surface tension (− 5.8 % at the melting temperature of pure iron of 1811 K).

Characterization of surfactant effectiveness and thus an evaluation of their performance in a wide range of emulsion technologies requires a precise determination of key parameters including their critical micelle concentrations as well as their ability to lower the surface tension at interfaces. In this study, we describe a new approach to quantify marginal variations in interfacial tension of surfactant stabilized fluid interfaces. The method is based on a unique chemical-morphological coupling inside bi-phasic oil-in-water Janus emulsions that undergo dynamic morphological transitions in response to changes in the surfactant type, concentration, ratio, and configuration. Variations in Janus droplet morphologies are readily monitored in-situ using a simple side-view imaging setup, resulting in a fast, convenient, cost-effective, time-, and sample-saving technique for the characterization of classical surfactant systems. In addition, the reported method facilitates a monitoring of triggered changes in surfactant effectiveness, e.g. invoked by external triggers, and thus proves particularly useful for the in-situ analysis of stimuli-responsive surfactants and emulsions.

The direct current potential drop method (DCPDM) is widely used to determine the crack length in fatigue experiments. In practice, some special features of this method must be considered. Aside from general information on the experimental setup and calibration, some special features of the method, such as the influence of the ambient atmosphere and the application of the method to ferromagnetic materials, are presented and discussed. In addition, with the multiple potential drop measurement, a method is presented which improves the resolution of the DCPDM for detection of cracks and allows to determine crack initiation sites. The capabilities provided by this method are demonstrated on the basis of measurements undertaken on notched round bars and single edged notched specimens.

Background: The interval between stimulus and response is called reaction time. It measures the sensorimotor function and performance of an individual. It involves stimulus processing, decision making and response programming. Many factors such as age, gender, handedness, physical fitness, sleep, fatigue, distraction, personality type and type of stimulus have been shown to affect reaction time. Thus the aim of this study was to assess the effect of body mass index, handedness and gender on reaction time.Methods: A cross-sectional study was conducted in the Department of Physiology, Kathmandu University School of Medical Sciences, from October 2019 to December 2019, among 113 student volunteers. Height and weight were recorded and body mass index was then calculated. In ruler drop method, the students were made to sit with their forearm resting on a flat horizontal table surface, with their open hand at the edge of the surface. When the examiner suspended and released the ruler vertically the students were instructed to catch it as quickly as possible.Results: Females had a faster reaction time than males when testing either hand (178.46±17.56 Vs 195.99±15.67; right hand) and (184.25±17.02 Vs 199.57±15.91; left hand). In females, right hand responded faster than left hand. In both gender, reaction time was faster in normal weight compared to overweight individuals but it was statistically insignificant.Conclusions: Females responded faster than males. Right hand had shorter reaction time than left hand in females. Reaction time was insignificantly prolonged in overweight individuals. Keywords: Body mass index; reaction time; ruler drop method

The China Experimental Fast Reactor (CEFR) is the first SFR operated in China. The CEFR physical start-up tests, conducted in 2010, included control rod (CR) worth (CRW) measurements by the rod drop method. In this study, the transient simulations of the actual course of eigth CR drop experiments have been performed with the Monte Carlo code Serpent using a detailed 3D heterogeneous CEFR core model. For each of the eight cases, the calculated time-depended neutron population, dynamic reactivity, and CRW have been compared to the measurements. The experimental and calculated reactivity curves have shown a very close behavior for the entire simulated time interval. With regard to the CRW results, a very good compliance between the experiment and simulations as well as among the applied computational approaches has been observed. The obtained results indicate that Serpent can be routinely applied to transient simulations, the area which until recently was limited to deterministic methods.

Mixtures of fluorinated and non-fluorinated ionic liquids (ILs) show a distinct structural organization in the bulk and at the surface. To understand how such microscopic effects influence the macroscopic bulk and surface properties of IL mixtures, knowledge of corresponding thermophysical properties including viscosity and surface tension is required yet lacking. With the intention of investigating surface enrichment effects of the fluorinated IL [PFBMIm][PF6] (3-methyl-1-(3,3,4,4,4-pentafluorobutyl)imidazolium hexafluorophosphate) in mixtures with the structurally similar, non-fluorinated IL [C4C1Im][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate) observed with angle-resolved X-ray photoelectron spectroscopy (ARXPS), the pendant drop method and surface light scattering (SLS) were applied in the present study to determine surface tension and dynamic viscosity between (293 and 368) K. By adding small amounts of [PFBMIm][PF6] up to 9 mol %, a distinct increase in the viscosity and decrease in the surface tension of the mixtures relative to the properties of pure [C4C1Im][PF6] was found. This behavior reflects the nanosegregated structure in the bulk and at the surface of the binary IL mixtures. Using the results about the pronounced surface enrichment of the fluorinated chain of [PFBMIm][PF6] quantified by ARXPS, a linear mixing rule for the surface tension of the IL mixtures based on the surface tensions of the pure ILs and the surface concentration of their most surface-active groups is suggested.

The surface tensions of aqueous cetyltrimethyl ammonium bromide and four polyethylene glycols were measured experimentally at the temperature of 298.15 K and the pressure of 1 atm. Then the surface tensions of aqueous (cetyltrimethyl ammonium bromide + polyethylene glycols) were measured at different concentrations. These measurements were conducted with the pendant drop method. The surface tensions of these aqueous solutions were described by using the equality of chemical potentials at the interface and bulk liquid. The calculated results showed a good agreement with experimental measurements, so the model was successfully applied to aqueous cetyltrimethyl ammonium bromide, polyethylene glycols, and their mixtures. Moreover, the surface coverage, molar surface area, and surface-to-solution distributions were determined by this model. The values of critical micelle concentration were obtained through surface tension measurements for each aqueous solution. The presence of polyethylene glycols increased the values of the critical micelle concentration and decreased the surface coverages of cetyltrimethyl ammonium bromide.

This paper reports the experimental values of the interfacial tension between a gas mixture (CO2 + H2) and water measured with the pendant drop method. The measurements were conducted for temperatures from 271.2 K to 280.2 K and pressures up to 7.0 MPa, at increments of 1 MPa. These temperature-pressure ranges were nearly close to the (CO2 + H2) hydrate-stability-zone but each result is obtained without existence of any hydrate. The temperature dependency of the interfacial tension in this system could not be observed, but the interfacial tension decreased almost linearly with increasing pressure, indicating that the observed decrease was caused by an increase in adsorption of the gas phase onto the liquid water with pressure. The gradient of the interfacial tension, with respect to the pressure, was confirmed to be determined by the gas phase composition. The interaction between gases has a marginal influence on the interfacial tension between the (CO2 + H2) gas mixture and water.

In present study, the asphaltene precipitation was examined through pendant drop method regarding the impacts of oil composition, solvent type and concentration in both atmospheric and elevated pre...

In total, 13 commercial wheat cultivars around China and four races of Puccinia striiformis f. sp. tritici (namely, CYR32, CYR33, G22-9, and G22-14) were employed for a test of relative parasitic fitness (RPF) using the drop method. The RPF values were measured, including the urediniospore germination rate, the latent period, the uredinial length, the uredinial density, the infection area, the sporulation intensity, the lesion expansion speed, and the sporulation period. The results indicated that the parameters of relative parasitic fitness of the four P. striiformis f. sp. tritici races on the 13 wheat cultivars were significantly different (P = 0.00) in sporulation intensity, lesion expansion speed, uredinial length, sporulation period, uredinial density, and latent period. The urediniospore germination rates of the four P. striiformis f. sp. tritici races for the test were significantly different (P = 0.00), whereas no correlation with the different cultivars was observed (P = 1.00). The infection areas of the tested races on the different cultivars were significantly different (P = 0.00) but there were no obvious manifestations among the various races (P = 0.20). Principal component analysis (PCA) showed that the sporulation intensity represented sporulation capacity and scalability, the latent period indicated infection ability, and the urediniospore germination rate represented urediniospore vigor, all of which fully contributed to the RPF in the interaction of the four races and 13 wheat cultivars, which was calculated by the following formula: RPF = (sporulation intensity × urediniospore germination rate)/latent period. The sporulation and infection of G22-9 on the 13 large-scale cultivated cultivars were the highest, and the RPF of G22-9 was higher than that of the predominant races, CYR32 and CYR33. This result suggested that G22-9 could become a new predominant race and potentially cause epidemics of wheat stripe rust in China. To prevent potential epidemics, susceptible wheat cultivars should be withdrawn from production and breeding programs should reduce the use of Yr10 and Yr26 and use other more effective resistance genes in combination with nonrace-specific resistance for developing wheat cultivars with durable resistance to stripe rust.