University of Lleida

About: University of Lleida is a education organization based out in Lleida, Spain. It is known for research contribution in the topics: Population & Pregnancy. The organization has 2939 authors who have published 5853 publications receiving 148417 citations. The organization is also known as: Escola Superior Politècnica & Universitat de Lleida.

Geomorphic effectiveness of check dams in a debris-flow catchment using multi-temporal topographic surveys

Abstract: Torrent control works, such as grade control dams and sediment retention dams, are structural measures for controlling debris flows and debris floods. In spite of the widespread presence of such hydraulic structures in steep mountain streams worldwide, there are still few studies monitoring the effects of check dams on sediment dynamics. The use of repeated topographic surveys allows us to characterize debris-flow activity at multiple temporal and spatial scales and its interaction with torrent control works. Structure from Motion (SfM) technique paired with Multi-View Stereo (MVS) algorithms represents a low-cost opportunity to conduct such multi-temporal surveys. This enables us to better study the effects of individual debris flows, track geomorphic changes and evaluate the effectiveness of torrent control works (e.g. check dams). The effect of check dams on sediment dynamics is investigated by means of multi-temporal topographic surveys before and after debris-flow events in the Moscardo torrent (eastern Italian Alps) where two check dams have recently been built. Multi-temporal SfM based on images taken from the ground in combination with imagery taken by an Unmanned Aerial Vehicle (UAV) is used to obtain DEMs and to study topographic changes through the comparison of repeat DEMs (DEM of Difference, i.e. DoD). The results show that the new check dams considerably modified sediment dynamics in the studied channel but their performance cannot be considered satisfactory. The sediment flowed around the upstream check dam on the right wing, while deep erosion observed downstream of the check dam threatened to undermine the foundation's stability. Moreover, debris-flow lobes deposited upstream of the check dams could act as sources of sediment further increasing downstream debris-flow volume. The analysis proposed in this work could help improve design strategies and permitting the identification of a proper site for check dam building.

Combined transcript, proteome, and metabolite analysis of transgenic maize seeds engineered for enhanced carotenoid synthesis reveals pleotropic effects in core metabolism

Abstract: The aim of this study was to assess whether endosperm-specific carotenoid biosynthesis influenced core metabolic processes in maize embryo and endosperm and how global seed metabolism adapted to this expanded biosynthetic capacity. Although enhancement of carotenoid biosynthesis was targeted to the endosperm of maize kernels, a concurrent up-regulation of sterol and fatty acid biosynthesis in the embryo was measured. Targeted terpenoid analysis, and non-targeted metabolomic, proteomic, and transcriptomic profiling revealed changes especially in carbohydrate metabolism in the transgenic line. In-depth analysis of the data, including changes of metabolite pools and increased enzyme and transcript concentrations, gave a first insight into the metabolic variation precipitated by the higher up-stream metabolite demand by the extended biosynthesis capacities for terpenoids and fatty acids. An integrative model is put forward to explain the metabolic regulation for the increased provision of terpenoid and fatty acid precursors, particularly glyceraldehyde 3-phosphate and pyruvate or acetyl-CoA from imported fructose and glucose. The model was supported by higher activities of fructokinase, glucose 6-phosphate isomerase, and fructose 1,6-bisphosphate aldolase indicating a higher flux through the glycolytic pathway. Although pyruvate and acetyl-CoA utilization was higher in the engineered line, pyruvate kinase activity was lower. A sufficient provision of both metabolites may be supported by a by-pass in a reaction sequence involving phosphoenolpyruvate carboxylase, malate dehydrogenase, and malic enzyme.

Antioxidants block proteasome inhibitor function in endometrial carcinoma cells

Abstract: We have recently demonstrated that proteasome inhibitors can be effective in inducing apoptotic cell death in endometrial carcinoma cell lines and primary culture explants. Increasing evidence suggests that reactive oxygen species are responsible for proteasome inhibitor-induced cell killing. Antioxidants can thus block apoptosis (cell death) triggered by proteasome inhibition. Here, we have evaluated the effects of different antioxidants (edaravone and tiron) on endometrial carcinoma cells treated with aldehyde proteasome inhibitors (MG-132 or ALLN), the boronic acid-based proteasome inhibitor (bortezomib) and the epoxyketone, epoxomicin. We show that tiron specifically inhibited the cytotoxic effects of bortezomib, whereas edaravone inhibited cell death caused by aldehyde-based proteasome inhibitors. We have, however, found that edaravone completely inhibited accumulation of ubiquitin and proteasome activity decrease caused by MG-132 or ALLN, but not by bortezomib. Conversely, tiron inhibited the ubiquitin accumulation and proteasome activity decrease caused by bortezomib. These results suggest that edaravone and tiron rescue cells of proteasome inhibitors from cell death, by inhibiting blockade of proteasome caused by MG-132 and ALLN or bortezomib, respectively. We also tested other antioxidants, and we found that vitamin C inhibited bortezomib-induced cell death. Similar to tiron, vitamin C inhibited cell death by blocking the ability of bortezomib to inhibit the proteasome. Until now, all the antioxidants that blocked proteasome inhibitor-induced cell death also blocked the proteasome inhibitor mechanism of action.

Influence of synthetic packing materials on the gas dispersion and biodegradation kinetics in fungal air biofilters

Abstract: The biodegradation of toluene was studied in two lab-scale air biofilters operated in parallel, packed respectively with perlite granules (PEG) and polyurethane foam cubes (PUC) and inoculated with the same toluene-degrading fungus. Differences on the material pore size, from micrometres in PEG to millimetres in PUC, were responsible for distinct biomass growth patterns. A compact biofilm was formed around PEG, being the interstitial spaces progressively filled with biomass. Microbial growth concentrated at the core of PUC and the excess of biomass was washed-off, remaining the gas pressure drop comparatively low. Air dispersion in the bed was characterised by tracer studies and modelled as a series of completely stirred tanks (CSTR). The obtained number of CSTR (n) in the PEG packing increased from 33 to 86 along with the applied gas flow (equivalent to empty bed retention times from 48 to 12 s) and with operation time (up to 6 months). In the PUC bed, n varied between 9 and 13, indicating that a stronger and steadier gas dispersion was achieved. Michaelis–Menten half saturation constant (km) estimates ranged 71–113 mg m−3, depending on the experimental conditions, but such differences were not significant at a 95% confidence interval. The maximum volumetric elimination rate (rm) varied from 23 to 50 g m−3 h−1. Comparison between volumetric and biomass specific biodegradation activities indicated that toluene mass transfer was slower with PEG than with PUC as a consequence of a smaller biofilm surface and to the presence of larger zones of stagnant air.