Physicochemical Properties of 3D-Printed Polylactic Acid/Hydroxyapatite Scaffolds.

The reconstruction or regeneration of damaged bone tissue is one of the challenges of orthopedic surgery and tissue engineering. Among all strategies investigated, additive manufacturing by fused deposition modeling (3D-FDM printing) opens the possibility to obtain patient-specific scaffolds with controlled architectures. The present work evaluates in depth 3D direct printing, avoiding the need for a pre-fabricated filament, to obtain bone-related scaffolds from direct mixtures of polylactic acid (PLA) and hydroxyapatite (HA).

Humic acids modify the pulse size distributions in the characterization of plastic microparticles by Tunable Resistive Pulse Sensing.

Tunable Resistive Pulse Sensing, TRPS, is an emerging technique used in quantification and measuring the size (particle-by-particle) of viruses, exosomes and engineered colloidal spheres in biological fluids. We study the features of TRPS to enhance size characterization and quantification of submicron-sized microplastics, also called plastic microparticles, MP, in freshwater environments. We report alterations on the detection of the resistive pulses in the TRPS caused by humic acids, HA, during the size measurement of polystyrene microspheres used as MP surrogate.

Effects of past copper contamination and soil structure on copper leaching from soil.

Copper contamination affects biological, chemical, and physical soil properties and associated ecological functions. Changes in soil pore organization as a result of Cu contamination can dramatically affect flow and contaminant transport in polluted soils. This study assessed the influence of soil structure on the movement of water and Cu in a long-term polluted soil.

Modeling the influence of raindrop size on the wash-off losses of copper-based fungicides sprayed on potato (Solanum tuberosum L.) leaves.

Modeling the pesticide wash-off by raindrops is important for predicting pesticide losses and the subsequent transport of pesticides to soil and in soil run-off. Three foliar-applied copper-based fungicide formulations, specifically the Bordeaux mixture (BM), copper oxychloride (CO), and a mixture of copper oxychloride and propylene glycol (CO-PG), were tested on potato (Solanum tuberosum L.) leaves using a laboratory raindrop simulator.

Phosphorus effect on Zn adsorption-desorption kinetics in acid soils.

The adsorption-desorption kinetics of Zn in the absence and presence of P was studied by using the stirred flow chamber technique. The results thus obtained were compared with those previously obtained for Cu. As with copper, the simultaneous addition of P and Zn in a 1:1 mole ratio to soil was found to significantly increased Zn adsorption relative to the absence of P.

Detachment of sprayed colloidal copper oxychloride-metalaxyl fungicides by a shallow water flow.

Background: Flow shear stress induced by rainfall promotes the loss of the pesticides sprayed on crops. Some of the factors influencing the losses of colloidal-size particulate fungicides are quantified by using a rotating shear system model. With this device it was possible to analyse the flow shear influencing washoff of a commercial fungicide formulation based on a copper oxychloride-metalaxyl mixture that was sprayed on a polypropylene surface.

Influence of methanol on the dynamics of the retention and release of cyprodinil by an agricultural soil.

The influence of methanol on the adsorption of the fungicide cyprodinil by a crop soil was studied by equilibrium measurements and by determining the retention-release dynamics in a continuous stirred flow tank reactor (CSTR). Equilibrium measurements showed the effective coefficient of partition of cyprodinil between soil and solution, K(dc), decreases linearly as the concentration of methanol in the solution increases until a percentage of 20% is reached. In CSTR experiments, the retention of cyprodinil was found to be almost reversible; up to a 95% of the fungicide was desorbed.