Background: The snail Helixa spersa is considered a relevant bioindicator of soil pollution by metallic elements due to its resistance and accumulation capabilities. Methods: This study aims to determine the dose-response relationship between different concentrations of lead and its toxic effects on juvenile H. aspersa through a semi-static ecotoxicity test under controlled conditions. In addition, continuous monitoring of carbohydrates, lipids and proteins of the snails affected by this metal was evaluated along with a histopathological study of the hepatopancreas. Result: The two-month lead exposure in H. aspersa resulted in significant alterations in biochemical and histological parameters. Lead concentrations in the hepatopancreas and foot exhibited a dose-dependent increase, with higher levels observed in the former. Elevated lead concentrations (1000 mu g/g and 1500 mu g/g of soil) led to substantial protein increase in both organs, while even lower doses displayed considerable protein elevation in the hepatopancreas. Carbohydrate levels were significantly lower in all contaminated groups compared to controls. Increasing lead concentrations caused a reduction in lipid levels. Histological analysis revealed distinct alterations, including excretory cell hypertrophy, tubule clustering and inflammatory changes in the hepatopancreas of treated snails. Severe histological damage, including inflammatory infiltrates, cellular debris and necrosis, were observed at higher lead concentrations (1000 and 1500 mu g/g). These findings emphasize the impact of lead exposure on biochemical profiles and organ histology in H. aspersa, highlighting the potential ecological implications of heavy metal contamination.

Screw piles have a greater bearing capacity than straight piles due to their larger helix. However, an excessively large helix can cause bending and reduce the soil bearing capacity. This study investigates the failure pattern and mechanical performance of screw pile helices through full-scale load tests and numerical analyses. The results revealed that the helix buckled at its connection to the shaft. Additionally, the geological characteristics of the soil in which the pile was located had a negligible effect on the mechanical properties of the helix. Furthermore, the shape of the anchor plate (flat or helical) had a negligible effect on the load-bearing properties of the pile or the mechanical properties of the anchor plate itself. To simplify the analysis, the screw pile helix was assumed to be a flat circular plate. For a uniformly loaded flat circular plate with fixed inner edges, the result of Roark's formula satisfactorily agreed with the measured maximum radial normal stress in the helix. Moreover, the value given by Roark's formula for a flat circular plate with simply supported inner edges agreed well with the measured helix deformation.

Recently, there is a renewed interest in Earth Observation (EO) of the cryosphere as a proxy of global warming, soil moisture for agriculture and desertification studies, and biomass for carbon storage. Global Navigation Satellite System-Reflectometry (GNSS-R) and L-band microwave Radiometry have been used to perform these measurements. However, it is expected that the combination of both can largely improve current observations. (3)Cat-4 mission aims at addressing this technology challenge by integrating a combined GNSS-R and Microwave Radiometer payload into a 1-Unit CubeSat. One of the greatest challenges is the design of an antenna that respects the envelope and stowage requirements of 1-Unit CubeSat, being able to work in the different frequency bands: Global Positioning System (GPS) L1-band (1575 MHz), GPS L2-band (1227 MHz), and microwave radiometry at 1400-1427 MHz. After a trade-off analysis, a helix antenna was found to be the most suitable option. This antenna has 11 turns equally distributed with 68.1 mm of diameter. This design generates an antenna with 506 mm of axial length, providing the maximum radiation gain in the endfire direction. Additionally, a counterweight is added at the tip of the antenna to enhance the directivity, and it is used as gravity gradient technique. The deployment of this antenna in vacuum and extreme temperature conditions is the greatest mechanical challenge that needs to be addressed for the success of the mission. This work presents a mechanical solution that enables to deploy the helix antenna from 25.5 mm (stowed configuration) to the final 506 mm (deployed configuration). By sequentially deploying different parts of the antenna, the final configuration is reached without impacting the attitude pointing of the CubeSat. This is accomplished using dyneema lines that are melted sequentially by commands. In addition, the deployment velocity, acceleration, and waving are presented as part of its characterization. The current test results in a Thermal Vacuum Chamber indicate also that the deployment can be achieved in -35 degrees C. The (3)Cat-4 CubeSat, with the L-band helix antenna, will be launched in Q4 2020 as part of the ''Fly Your Satellite!'' program of the European Space Agency (ESA).