Influence of slope incline on the ejection of two-phase soil splashed material

Soil splash is the first step in the process of water erosion, where impacting raindrops cause the detachment and transport of soil material. One of the factors that strongly influences the magnitude of soil splash is the incline of the surface (slope). The aim of this study was to investigate the effect of the slope on the course of the splash phenomenon caused by single-drop impact (one drop impact per soil sample), with respect to the mass and proportions of the ejected material, taking into account its division into solid and liquid phases i.e. soil and water. The investigation was carried out using three types of soil with different textures, in moistened (pressure head corresponding to -1.0 kPa) and air-dry (-1500 kPa) conditions. The soil samples were on three angles of slope, being 5°, 15°, and 30°, respectively. After a single-drop impact with a diameter of 4.2 mm, the ejected material was collected using a splash cup. The following quantities of splashed material were measured: the total mass, the mass of the solid phase, and the mass of the liquid phase. Additionally, the distribution and proportions (soil/water) of the splashed material were analysed in both the upslope and downslope directions. It was found that: (i) the change of slope had a variable influence on the measured quantities for different soils; (ii) in the case of moistened samples, the measured values were mainly influenced by the texture, while in the dry samples, by the angle of the slope; (iii) with the increase of slope, the splashed material was mostly ejected in the downslope direction (irrespective of moisture conditions); (iv) in the moistened samples, the ejected material consisted mostly of water, while in the dry samples it was soil—this occurred for material ejected both upslope and downslope. The obtained results are important for improving the physical description of the process of splash erosion. A more thorough understanding and better recognition of the mechanisms governing this phenomenon at all stages could contribute to the development of more effective methods for protecting soil against erosion.

A Dual Electrode Biosensor for Glucose and Lactate Measurement in Normal and Prolonged Obese Mice Using Single Drop of Whole Blood

Understanding the levels of glucose (G) and lactate (L) in blood can help us regulate various chronic health conditions such as obesity. In this paper, we introduced an enzyme-based electrochemical biosensor adopting glucose oxidase and lactate oxidase on two working screen-printed carbon electrodes (SPCEs) to sequentially determine glucose and lactate concentrations in a single drop (~30 µL) of whole blood. We developed a diet-induced obesity (DIO) mouse model for 28 weeks and monitored the changes in blood glucose and lactate levels. A linear calibration curve for glucose and lactate concentrations in ranges from 0.5 to 35 mM and 0.5 to 25 mM was obtained with R-values of 0.99 and 0.97, respectively. A drastic increase in blood glucose and a small but significant increase in blood lactate were seen only in prolonged obese cases. The ratio of lactate concentration to glucose concentration (L/G) was calculated as the mouse’s gained weight. The results demonstrated that an L/G value of 0.59 could be used as a criterion to differentiate between normal and obesity conditions. With L/G and weight gain, we constructed a diagnostic plot that could categorize normal and obese health conditions into four different zones. The proposed dual electrode biosensor for glucose and lactate in mouse whole blood showed good stability, selectivity, sensitivity, and efficiency. Thus, we believe that this dual electrode biosensor and the diagnostic plot could be used as a sensitive analytical tool for diagnosing glucose and lactate biomarkers in clinics and for monitoring obesity.

Sub-Minute Analysis of Lactate from a Single Blood Drop Using Capillary Electrophoresis with Contactless Conductivity Detection in Monitoring of Athlete Performance

A simple and fast method for the analysis of lactate from a single drop of blood was developed. The finger-prick whole blood sample (10 µL) was diluted (1:20) with a 7% (w/v) solution of [tris(hydroxymethyl)methylamino] propanesulfonic acid and applied to a blood plasma separation device. The device accommodates a membrane sandwich composed of an asymmetric polysulfone membrane and a supporting textile membrane that allows the collection of blood plasma into a narrow glass capillary in less than 20 s. Separated and simultaneously diluted blood plasma was directly injected into a capillary electrophoresis instrument with a contactless conductivity detector (CE-C4D) and analyzed in less than one minute. A separation electrolyte consisted of 10 mmol/L l-histidine, 15 mmol/L dl-glutamic acid, and 30 µmol/L cetyltrimethylammonium bromide. The whole procedure starting from the finger-prick sampling until the CE-C4D analysis was finished, took less than 5 min and was suitable for monitoring lactate increase in blood plasma during incremental cycling exercise. The observed lactate increase during the experiments measured by the developed CE-C4D method correlated well with the results from a hand-held lactate analyzer (R = 0.9882). The advantage of the developed CE method is the speed, significant savings per analysis, and the possibility to analyze other compounds from blood plasma.