Deterministic and probabilistic models for the estimation of nitrate loads in a rural basin

En este trabajo se desarrolló un modelo probabilístico que utiliza la teoría de la función de densidad de probabilidades derivada para estimar la carga media anual de nitratos transportada por el escurrimiento superficial, utilizando una relación funcional entre el escurrimiento y la carga de nitratos. El modelo determinístico hidrológico y de calidad de agua denominado Simulator for Water Resources in Rural Basins - Water Quality (SWRRB-WQ) fue utilizado para estimar la carga de nitratos en el escurrimiento superficial. Este modelo emplea como variable de entrada la precipitación diaria observada en la Estación del Aeropuerto de Olavarría durante el período 1988 a 2002. Para la calibración del modelo se aplicó una nueva metodología que estima la incertidumbre en los valores observados. Ambos modelos probabilístico y determinístico se aplican en una subcuenca rural del arroyo Tapalqué (provincia de Buenos Aires, Argentina) y finalmente se comparan los valores de la carga de nitratos estimados con los dos modelos con las observaciones realizadas en la sección del arroyo motivo de este estudio. Los resultados muestran que la carga media de nitratos obtenida con el modelo probabilístico es del mismo orden de magnitud que los valores medios observados y estimados con el modelo hidrológico y de calidad de agua SWRRB-WQ.In this work a new probabilistic model was developed. The new model applies the derived density function theory to estimate nitrate mean annual load transported by surface runoff. A functional relationship between runoff and nitrate load was used. The deterministic hydrologic and water quality model Simulator for Water Resources in Rural Basins - Water Quality (SWRRB-WQ) was used to estimate nitrate load in surface runoff. This model uses, as input variable, daily precipitation observed at Olavarría Airport Meteorological Station, for the 1988-2002 period. For model calibration a new method that estimates uncertainty in observed values is applied. Both probabilistic and deterministic hydrologic models are applied in a rural subbasin of Tapalqué River (province of Buenos Aires, Argentina). Finally, estimated and observed nitrate loads are compared at the outlet section of the subbasin under study. The results of applying the selected probabilistic model show that the mean nitrate loads obtained, are of the same order of magnitude that the mean nitrate loads observed and estimated with the SWRRB-WQ hydrologic and water quality model.Fil: Gelmi, Mónica E.. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería.Fil: Seoane, Rafael. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto Nacional del Agua

Phosphorus recovery from a pilot-scale grate furnace: influencing factors beyond wet chemical leaching conditions

Phosphorus is a non-renewable resource going to exhaustion in the future. Sewage sludge ash is a promising secondary raw material due to its high phosphorus content. In this work, the distribution of 19 elements in bottom and cyclone ashes from pilot-scale grate furnace have been monitored to determine the suitability for the phosphorus acid extraction. Moreover, the influence of some parameters beyond wet chemical leaching conditions were investigated. Experimental results showed that bottom ash presented lower contamination in comparison to cyclone ash and low co-dissolution of heavy metals (especially Cr, Pb and Ni), while high phosphorus extraction efficiencies (76-86%) were achieved. High Al content in the bottom ash (9.4%) negatively affected the phosphorus extraction efficiency as well as loss on ignition, while the particle size reduction was necessary for ensuring a suitable contact surface. The typology of precipitating agents did not strongly affect the phosphorus precipitation, while pH was the key parameter. At pH 3.5-5, phosphorus precipitation efficiencies higher than 90% were achieved, with a mean phosphorus content in the recovered material equal to 16-17%, comparable to commercial fertilizers. Instead, the co-precipitation of Fe and Al had a detrimental effect on the recovered material, indicating the need for additional treatments

Bio-inspired fabrication of DNA-inorganic hybrid composites using synthetic DNA

Nucleic acid nanostructures have attracted significant interest as potential therapeutic and diagnostic platforms due to their intrinsic biocompatibility and biodegradability, structural and functional diversity, and compatibility with various chemistries for modification and stabilization. Among the fabrication approaches for such structures, the rolling circle techniques have emerged as particularly promising, producing morphologically round, flower-shaped nucleic acid particles: typically hybrid composites of long nucleic acid strands and inorganic magnesium pyrophosphate (Mg2PPi). These constructs are known to form via anisotropic nucleic acid-driven crystallization in a sequence-independent manner, rendering monodisperse and densely packed RNA or DNA–inorganic composites. However, it still remains to fully explore how flexible polymer-like RNA or DNA strands (acting as biomolecular additives) mediate the crystallization process of Mg2PPi and affect the structure and properties of the product crystals. To address this, we closely examined nanoscale details to mesoscopic features of Mg2PPi/DNA hybrid composites fabricated by two approaches, namely rolling circle amplification (RCA)-based in situ synthesis and long synthetic DNA-mediated crystallization. Similar to the DNA constructs fabricated by RCA, the rapid crystallization of Mg2PPi was retarded on a short-range order when we precipitated the crystals in the presence of presynthesized long DNA, which resulted in effective incorporation of biomolecular additives such as DNA and enzymes. These findings further provide a more feasible way to encapsulate bioactive enzymes within DNA constructs compared to in situ RCA-mediated synthesis, i.e., by not only protecting them from possible denaturation under the reaction conditions but also preventing nonselective association of proteins arising from the RCA reaction mixtures

Modelos determinístico y probabilístico para la estimación de la carga de nitratos en una cuenca rural

In this work a new probabilistic model was developed. The new model applies the derived density function theory to estimate nitrate mean annual load transported by surface runoff. A functional relationship between runoff and nitrate load was used. The deterministic hydrologic and water quality model Simulator for Water Resources in Rural Basins - Water Quality (SWRRB-WQ) was used to estimate nitrate load in surface runoff. This model uses, as input variable, daily precipitation observed at Olavarría Airport Meteorological Station, for the 1988-2002 period. For model calibration a new method that estimates uncertainty in observed values is applied. Both probabilistic and deterministic hydrologic models are applied in a rural subbasin of Tapalqué River (province of Buenos Aires, Argentina). Finally, estimated and observed nitrate loads are compared at the outlet section of the subbasin under study. The results of applying the selected probabilistic model show that the mean nitrate loads obtained, are of the same order of magnitude that the mean nitrate loads observed and estimated with the SWRRB-WQ hydrologic and water quality model.En este trabajo se desarrolló un modelo probabilístico que utiliza la teoría de la función de densidad de probabilidades derivada para estimar la carga media anual de nitratos transportada por el escurrimiento superficial, utilizando una relación funcional entre el escurrimiento y la carga de nitratos. El modelo determinístico hidrológico y de calidad de agua denominado Simulator for Water Resources in Rural Basins - Water Quality (SWRRB-WQ) fue utilizado para estimar la carga de nitratos en el escurrimiento superficial. Este modelo emplea como variable de entrada la precipitación diaria observada en la Estación del Aeropuerto de Olavarría durante el período 1988 a 2002. Para la calibración del modelo se aplicó una nueva metodología que estima la incertidumbre en los valores observados. Ambos modelos probabilístico y determinístico se aplican en una subcuenca rural del arroyo Tapalqué (provincia de Buenos Aires, Argentina) y finalmente se comparan los valores de la carga de nitratos estimados con los dos modelos con las observaciones realizadas en la sección del arroyo motivo de este estudio. Los resultados muestran que la carga media de nitratos obtenida con el modelo probabilístico es del mismo orden de magnitud que los valores medios observados y estimados con el modelo hidrológico y de calidad de agua SWRRB-WQ

Non-standard amino acids and peptides : From self-assembly to nanomaterials

The exploitation of peptides in the development of smart nanomaterials is gaining increasing attention in the last few years. Amino acids are indeed able to drive the self-assembly and the self-organization at the molecular level. By using non-standard amino acids, it is possible to expand the scope of the possible applications, ranging from biomaterials, biosensors to drug delivery systems. In this digest, the recent advances in this field are presented

Tetrahydro-4H-(pyrrolo[3,4-d]isoxazol-3-yl)methanamine : a bicyclic diamino scaffold stabilizing parallel turn conformations

Tetrahydro-4H-(pyrrolo[3,4-d]isoxazol-3-yl)methanamine scaffold was designed as diamino derivative to stabilize parallel turn conformations. Its synthesis took advantage of a [1,3]-dipolar cycloaddition reaction between the nitrile oxide derived from the inexpensive enantiopure L-phenylalanine, and N-benzyl-3-pyrroline. Two diastereoisomers were formed whose distribution depends on the selected base. 3aR,6aS-Isomer is favoured in organic bases which formation is driven by pi-interactions. On the other hand, the above interactions were significantly prevented using an inorganic base due to the chaotropic effect of the cation, decreasing the amount of the above isomer. Finally, we demonstrated that this isomer is able of stabilizing parallel turn conformations when inserted in short peptide sequences

Tuning PFKFB3 Bisphosphatase Activity Through Allosteric Interference

The human inducible phospho-fructokinase bisphosphatase isoform 3, PFKFB3, is a crucial regulatory node in the cellular metabolism. The enzyme is an important modulator regulating the intracellular fructose-2,6-bisphosphate level. PFKFB3 is a bifunctional enzyme with an exceptionally high kinase to phosphatase ratio around 740:1. Its kinase activity can be directly inhibited by small molecules acting directly on the kinase active site. On the other hand, here we propose an innovative and indirect strategy for the modulation of PFKFB3 activity, achieved through allosteric bisphosphatase activation. A library of small peptides targeting an allosteric site was discovered and synthesized. The binding affinity was evaluated by microscale thermophoresis (MST). Furthermore, a LC-MS/MS analytical method for assessing the bisphosphatase activity of PFKFB3 was developed. The new method was applied for measuring the activation on bisphosphatase activity with the PFKFB3-binding peptides. The molecular mechanical connection between the newly discovered allosteric site to the bisphosphatase activity was also investigated using both experimental and computational methods

Sampling Mechanism for Low Gravity Bodies

In future exploration missions to low gravity bodies (e.g. a Mars moon or a near-Earth asteroid) it is planned to collect more than 100 grams of soil and return them to Earth. In previous studies several sampling tools have been proposed but there is no single sampling technology for low-gravity bodies that has been specifically conceived to provide the ability to collect material in any envisaged situation. Low gravity bodies present indeed peculiar conditions which need to be taken into account during the design and test of sampling and sample handling systems. Primarily, the very reduced gravity limits the thrust reaction capability in support to drilling operations; and, although reactions can be achieved by spacecraft anchoring or by thrust reversal, these operative conditions could limit the effectiveness of the sampling action. An alternative solution is the exploitation of the forces naturally arising from Spacecraft momentum inversion, which can be achieved by ‘touch and go’ techniques (as e.g. performed in Hayabusa mission). Although the small duration of the contact with the soil would anyhow limit the sampling depth and the collectable soil types, a properly designed sampling system would require to conclude the operation with a great effectiveness. In the last three years an ESA founded study has been carried on and a fully functional sampling mechanism for "touch and go" sampling on a low-gravity body has been selected, designed and breadboarded. Based on the results of several Proof-Of-Principle models tested on different types of specimen and after the analysis performed on a dynamic simulation model for the sampling action, a device implementing the most promising sampling technique has been designed and manufactured. It has been then tested under ambient conditions using various kinds of asteroid soil stimulants. The proposed paper will resume the key aspects and the main achievements of the study

Retinoblastoma Is Characterized by a Cold, CD8+ Cell Poor, PD-L1- Microenvironment, Which Turns Into Hot, CD8+ Cell Rich, PD-L1+ After Chemotherapy

PURPOSE. To investigate the impact of chemotherapy (CHT) on human retinoblastoma (RB) tumor microenvironment (TME).CASES AND METHODS. Ninety-four RBs were studied, including 44 primary RBs treated by upfront surgery (Group 1) and 50 primary RBs enucleated after CHT (CHT), either intraarterial (IAC; Group 2, 33 cases) or systemic (S-CHT; Group 3, 17 cases). Conventional and multiplexed immunohistochemistry were performed to make quantitative comparisons among the three groups, for the following parameters: tumor-infiltrating inflammatory cells (TI-ICs); programmed cell death protein 1 (PD-1) positive TI-ICs; Ki67 proliferation index; gliosis; PD-1 ligand (PD-L1) protein expression; vessel number. We also correlated these TME factors with the presence of histological high-risk factors (HHRF+) and RB anaplasia grade (AG).RESULTS. After CHT, a decrease in both RB burden and Ki67 positivity was observed. In parallel, most subsets of TI-ICs, PD-1+ TI-ICs, gliosis, and PD-L1 protein expression significantly increased (P < 0.001, P = 0.02, P < 0.001, respectively). Vessel number did not significantly vary. Age, HHRFs+ and AG were significantly different between primary and chemoreduced RBs (P < 0.001, P = 0.006, P = 0.001, respectively) and were correlated with most TME factors.CONCLUSIONS. CHT modulates host antitumor immunity by reorienting the RB TME from anergic into an active, CD8+, PD-L1+ hot state. Furthermore, some clinicopathological characteristics of RB correlate with several factors of TME. Our study adds data in favor of the possibility of a new therapeutic scenario in human RB

Ctr-1 Mets7 motif inspiring new peptide ligands for Cu(i)-catalyzed asymmetric Henry reactions under green conditions

Taking inspiration from the Ctr-1 Mets7 Cu(i) binding motif, effective hybrid catalysts have been developed for asymmetric Henry condensations under green conditions. The introduction of an unnatural dipeptide mimic allowed to increase the catalytic performance. Metal transporters' binding domains could be exploited as a strategy for designing hybrid catalysts for homogeneous catalysis