Short-Term Response of Cytosolic N O 3 - to Inorganic Carbon Increase in Posidonia oceanica Leaf Cells.

The concentration of CO2 in the atmosphere has increased over the past 200 years and is expected to continue rising in the next 50 years at a rate of 3 ppm·year-1. This increase has led to a decrease in seawater pH that has changed inorganic carbon chemical speciation, increasing the dissolved HC O 3 - . Posidonia oceanica is a marine angiosperm that uses HC O 3 - as an inorganic carbon source for photosynthesis. An important side effect of the direct uptake of HC O 3 - is the diminution of cytosolic Cl- (Cl-c) in mesophyll leaf cells due to the efflux through anion channels and, probably, to intracellular compartmentalization. Since anion channels are also permeable to N O 3 - we hypothesize that high HC O 3 - , or even CO2, would also promote a decrease of cytosolic N O 3 - ( N O 3 - c ). In this work we have used N O 3 - - and Cl--selective microelectrodes for the continuous monitoring of the cytosolic concentration of both anions in P. oceanica leaf cells. Under light conditions, mesophyll leaf cells showed a N O 3 - c of 5.7 ± 0.2 mM, which rose up to 7.2 ± 0.6 mM after 30 min in the dark. The enrichment of natural seawater (NSW) with 3 mM NaHCO3 caused both a N O 3 - c decrease of 1 ± 0.04 mM and a Cl c - decrease of 3.5 ± 0.1 mM. The saturation of NSW with 1000 ppm CO2 also produced a diminution of the N O 3 - c , but lower (0.4 ± 0.07 mM). These results indicate that the rise of dissolved inorganic carbon ( HC O 3 - or CO2) in NSW would have an effect on the cytosolic anion homeostasis mechanisms in P. oceanica leaf cells. In the presence of 0.1 mM ethoxyzolamide, the plasma membrane-permeable carbonic anhydrase inhibitor, the CO2-induced cytosolic N O 3 - diminution was much lower (0.1 ± 0.08 mM), pointing to HC O 3 - as the inorganic carbon species that causes the cytosolic N O 3 - leak. The incubation of P. oceanica leaf pieces in 3 mM HC O 3 - -enriched NSW triggered a short-term external N O 3 - net concentration increase consistent with the N O 3 - c leak. As a consequence, the cytosolic N O 3 - diminution induced in high inorganic carbon could result in both the decrease of metabolic N flux and the concomitant biomass N impoverishment in P. oceanica and, probably, in other aquatic plants

Molecular Determinants for the Activation/Inhibition of Bak Protein by BH3 Peptides

Apoptosis is a key procedure for all cells. Understanding this process and its regulation has been a subject of study in the last decades. Bcl-2 family of proteins are involved in the regulation of the apoptosis through the formation of homodimers or heterodimers between anti-apoptotic and pro-apoptotic proteins. Deregulation of pro-apoptotic proteins contributes to the progression of many tumour processes. Understanding how these proteins are activated is key to find new anti-cancer treatments. As no drug capable of activating Bak has been discovered yet, studying the structural and energetic insights of the binding of the known Bak activators, BH3 peptides, is essential to design new small molecules that resemble their binding to Bak. Recently, a BH3 Bim analogue has been discovered which inactivates Bak instead of activating it. Therefore, the present work is aimed to identify how BH3 peptides activate or inactivate Bak and determine any difference between them. Determination of the structural differences between the complexes with the activator and the inhibitor has been carried out by means of the study of the fluctuations of the corresponding Principal Components. Moreover, to calculate the binding free energy of the different complexes and to determine which residues of the peptide have the largest contribution to complex formation, MMPB/GBSA approaches are used. Results obtained in this work show differences in complexes with the activator and the inhibitor in structural and energetic terms, which can be used in the design of new molecules that could activate or inactivate pro-apoptotic Bak

Shape Memory Hydrogels Based on Noncovalent Interactions

Shape memory polymers (SMPs) are polymeric materials that are capable of fixing temporary shape and recovering the permanent shape in response to external stimuli. In particular, supramolecular interactions and dynamic covalent bond have recently been introduced as temporary switches to construct supramolecular shape memory hydrogels (SSMHs), arising as promising materials since they can exhibit excellent cycled shape memory behavior at room temperature. On the other hand, hydrogels, conventionally, are flexible but sometimes extremely soft, and they can be easily damaged under external force, which could limit their long-time application. Therefore, self-healing hydrogels that can be rapidly auto-repaired when the damage occurs have been recently developed to solve this problem. These materials present more than one triggering stimulus that can be used to induce the shape memory and self-healing effect. These driven forces can be originated from hydrogen bonds, hydrophobic interactions, and reversible covalent bonds, among others. Beyond all these, hybrid organic-inorganic interactions represent an interesting possibility due to their versatility and favorable properties that allow the fabrication of multiresponsive hydrogels. In this chapter, shape memory hydrogels based on noncovalent interactions are described

Robust Federated Learning for execution time-based device model identification under label-flipping attack

The computing device deployment explosion experienced in recent years, motivated by the advances of technologies such as Internet-of-Things (IoT) and 5G, has led to a global scenario with increasing cybersecurity risks and threats. Among them, device spoofing and impersonation cyberattacks stand out due to their impact and, usually, low complexity required to be launched. To solve this issue, several solutions have emerged to identify device models and types based on the combination of behavioral fingerprinting and Machine/Deep Learning (ML/DL) techniques. However, these solutions are not appropriate for scenarios where data privacy and protection are a must, as they require data centralization for processing. In this context, newer approaches such as Federated Learning (FL) have not been fully explored yet, especially when malicious clients are present in the scenario setup. The present work analyzes and compares the device model identification performance of a centralized DL model with an FL one while using execution time-based events. For experimental purposes, a dataset containing execution-time features of 55 Raspberry Pis belonging to four different models has been collected and published. Using this dataset, the proposed solution achieved 0.9999 accuracy in both setups, centralized and federated, showing no performance decrease while preserving data privacy. Later, the impact of a label-flipping attack during the federated model training is evaluated using several aggregation mechanisms as countermeasures. Zeno and coordinate-wise median aggregation show the best performance, although their performance greatly degrades when the percentage of fully malicious clients (all training samples poisoned) grows over 50%

Fragment Dissolved molecular dynamics: A systematic and efficient method to locate binding sites.

Fragment-based drug discovery (FBDD) has been popular in the last decade, but some drawbacks, such as protein denaturation or ligand aggregation, have not yet clearly overcome in the framework of biomolecular simulations. In this work a systematic and semi-automatic method is presented as a novel proposal, named fragment dissolved Molecular Dynamics (fdMD), to improve research in future FBDD projects. Our method employs simulation boxes of solvated small fragments, adding a repulsive Lennard-Jones potential term to avoid aggregation, which can be easily used to solvate the object of interest. This method has the advantage of solvating the target with a low number of ligands, thus preventing this way denaturation of the target, while simultaneously generating a database of ligand-solvated boxes that can be used with other targets. A number of scripts are made available to analyze the results and obtain the descriptors proposed as a means of trustfully discard spurious binding sites. To test our method, four sets of different complexity have been solvated with ligand boxes and four molecular dynamics runs of 200 ns length have been run for each system, which have been extended up to 1 μs when needed. The reported results point that the selected number of replicas are enough to identify the correct binding sites irrespective of the initial structure, even in the case of proteins having several close binding sites for the same ligand. Among the proposed descriptors, average MMGBSA and average KDEEP energies emerge as the most robust ones

Awareness of Practice and Comparison with Best Evidence in Surgical Site Infection Prevention in Colorectal Surgery

Background: The use of mechanical bowel preparation and prophylaxis with oral antimicrobial agents can prevent surgical site infection (SSI) in colorectal surgical procedures, but routine adoption of these and other practices by surgeons has been limited. The aim of this study was to determine the actual practice and surgeon beliefs about preventative measures in elective colorectal operations and to compare them with established recommendations. Methods: Web-based survey was sent to colorectal surgeons assessing knowledge, beliefs, and practices regarding the use of preventative measures for SSI. Results: Of 355 surgeons, 33% had no feedback of SSI rate; 60% believed in evidence for normothermia, wound edge protection, and use of alcohol solution, and reported use of these strategies. There was a discrepancy in the assumed evidence and use of hyperoxia, glove replacement after anastomosis, surgical tools replacement, and saline surgical site lavage. Most of respondents believe that oral antibiotic prophylaxis diminishes infection, but is indicated only by one third of them. Few surgeons believe in MBP, but many actually use it. Most surgeons believe that there is a discrepancy between published guidelines and actual clinical practice. As proper means to implement guidelines, checklists, standardized orders, surveillance, feedback of SSI rates, and educational programs are rated most highly by surgeons, but few of these are in place at their institutions. Conclusions: Gaps in the translation of evidence into practice remain in the prevention of SSI in colorectal surgical procedures. Several areas for improvement have been identified. Specific implementation strategies should be addressed in colorectal units

Serum Collagen Type II Cleavage Epitope and Serum Hyaluronic Acid as Biomarkers for Treatment Monitoring of Dogs with Hip Osteoarthritis

The aim of this study was to evaluate the use of serum type II collagen cleavage epitope and serum hyaluronic acid as biomarkers for treatment monitoring in osteoarthritic dogs. For this purpose, a treatment model based on mesenchymal stem cells derived from adipose tissue combined with plasma rich in growth factors was used. This clinical study included 10 dogs with hip osteoarthritis. Both analytes were measured in serum at baseline, just before applying the treatment, and 1, 3, and 6 months after treatment. These results were compared with those obtained from force plate analysis using the same animals during the same study period. Levels of type II collagen cleavage epitope decreased and those of hyaluronic acid increased with clinical improvement objectively verified via force plate analysis, suggesting these two biomarkers could be effective as indicators of clinical development of joint disease in dogs. Introductio

Biomateriales: desarrollo de andamios para ingeniería de tejidos

El presente trabajo se centra en el desarrollo de andamios basados en colágeno (C) y/o quitosano (CH) mediante variaciones del método de fabricación basado en la creación de hidrogeles y posterior secado por liofilización. Con objeto de evaluar la composición y el método de fabricación de los andamios, se evalúan sus propiedades mecánicas mediante barridos de deformación y de frecuencia, así como su estructura y disposición de las fibras mediante porosimetría y microscopía electrónica de barrido (SEM). Los resultados obtenidos demuestran que las propiedades de los andamios experimentan una fuerte dependencia tanto con la proporción de las materias primas (C y CH), así como con el método de fabricación. De hecho, se encuentra que se produce una sinergia relevante cuando se emplean sistemas con la misma proporción de colágeno y quitosano en su composición.The present work focuses on the development of scaffolds based on collagen (C) and / or chitosan (CH) by variations of the manufacturing method by creation of hydrogels and subsequent freeze-drying. To evaluate the composition and method of manufacture of the scaffolding, its mechanical properties are evaluated by deformation and frequency sweeps, as well as its structure and arrangement of the fibers by means of porosimetry and scanning electron microscopy (SEM). The results obtained show that the properties of the scaffolds experience a strong dependence both with the proportion of the raw materials (C and CH), as well as with the manufacturing method. In fact, it is found that a relevant synergy occurs when systems with the same proportion of collagen and chitosan in their composition are used.Ministerio de Economía, Industria y Competitividad (España)/ / FEDER (UE) CTQ2015-71164PUniversidad de Sevilla Beca predoctoral del V Plan Propio (VPPI-US