Application of machine learning techniques to optical communication systems and networks

This TFM reviews the application of machine learning techniques in optical communication systems and networks. In addition, it studies and compares the characteristics of various machine learning methods, such as: support vector machines, logistic regression, decision trees and random forests, to predict the quality of transmission when using optical circuits in wavelength routed optical communication networks. The models developed in this TFM offer better performance than previous proposals, mainly in terms of computing time, making possible its use in online mode even in highly dynamic networks, in addition to being simpler.El presente TFM realiza una revisión de la aplicación de técnicas de aprendizaje automático en los sistemas y redes de comunicaciones ópticas. Además, estudia y compara las características de diversos métodos de aprendizaje automático, tales como: máquinas de vectores soporte, regresión logística, árboles de decisión y bosques aleatorios, para predecir la calidad de la transmisión al emplear circuitos ópticos en redes de comunicaciones ópticas con encaminamiento por longitud de onda. Los modelos desarrollados en el TFM obtienen mejores prestaciones que propuestas anteriores, fundamentalmente en términos de tiempo de cálculo, posibilitando su utilización en modo on-line incluso en redes altamente dinámicas, amén de ser más sencillos.Departamento de Teoría de la Señal y Comunicaciones e Ingeniería TelemáticaMáster en Investigación en Tecnologías de la Información y las Comunicacione

PEGylated AgNP covered with cationic carbosilane dendrons to enhance antibacterial and inhibition of biofilm properties

This work focuses on preparation of silver nanoparticles (AgNP) covered with cationic carbosilane dendrons and poly(ethylene glycol) (PEG). It is well known that AgNP and cationic carbosilane dendritic systems present antibacterial properties. On the other hand, PEG ligand provides antifouling properties and improved biocompatibility. Hence, combination of both ligands, carbosilane dendrons and PEG, on the AgNP surface can be a way to improve antibacterial capacity of AgNP. The new family of heterofunctionalized AgNP has been directly synthesized using silver precursor and cationic carbosilane dendrons and PEG ligands containing a thiol moiety. AgNP were characterized by TEM, TGA, UV, H-1 NMR, DLS, Z potential, XRD. The antibacterial capacity of these systems was evaluated against E. coli and S. aureus. The results confirmed the influence of both silver core and cationic carbosilane dendrons on the activity of these systems. The behaviour obtained for PEGylated systems were slightly lower than for non-PEGylated AgNP. However, hemolysis assays demonstrated that this decrease was compensated for by the greater biocompatibility. To more completely characterize the improvements of PEGylation on dendronized AgNP, one non-PEGylated and one PEGylated AgNP were tested for resistance in a planktonic state. Both AgNPs barely affected the minimum inhibitory concentration (MIC) whereas reference antibiotics generated significant resistance. In addition, relevant improvement in biofilm inhibition was achieved by dendronized AgNP after PEGylation.Universidad de AlcaláMinisterio de Economía, Industria y CompetitividadJunta de Comunidades de Castilla-La ManchaComunidad de Madri

Functionalization of silica with amine and ammonium alkyl chains, dendrons and dendrimers: Synthesis and antibacterial properties

Materials modified with ammonium groups on the surface have shown antibacterial activity. In this paper, alkyl chains, carbosilane (CBS) dendrimers and dendrons and poly(amidoamine) (PAMAM) dendrimers containing amine and ammonium groups have been grafted to silica surface and the influence of molecule structure on the stability and on antibacterial activity have been evaluated. These materials have been characterized by thermogravimetric analysis (TGA), zeta (Z) potential, scanning electron microscopy (SEM), infrared spectroscopy (IR) and nuclear magnetic resonance (C-13 CP MAS NMR). The degree of silica functionalization depends on type of outer groups, amine or ammonium, type and core of dendrimer, and length of chains. The Z potential measurements of these materials in water suspensions were used to test their stability in this medium. These measurements showed, for some of the modified silicas, the diminishing of Z potential from positive values toward zero, probably due to interaction of the functional groups with the silica surface. This variation was also dependent on ligand structure and peripheral functions. Finally, studies of inhibition of bacteria growth stand out again the relevance of ligand structure and number of functional groups on silica surface. The most active systems were those with more surface covered, those with cationic groups further away from silica surface and higher dendritic generation.Universidad de AlcaláMinisterio de Economía, Industria y CompetitividadComunidad de Madri

Carbosilane dendritic nanostructures, highly versatile platforms for pharmaceutical applications

Dendrimers are multifunctional molecules with well-defined size and structure due to the step-by-step synthetic procedures required in their preparation. Dendritic constructs based on carbosilane scaffolds present carbon-carbon and carbon-silicon bonds, which results in stable, lipophilic, inert, and flexible structures. These properties are highly appreciated in different areas, including the pharmaceutical field, as they can increase the interaction with cell membranes and improve the therapeutic action. This article summarizes the most recent advances in the pharmaceutical applications of carbosilane dendritic molecules, from therapeutics to diagnostics and prevention tools. Dendrimers decorated with cationic, anionic, or other moieties, including metallodendrimers; supramolecular assemblies; dendronized nanoparticles and surfaces; as well as dendritic networks like hydrogels are described. The collected examples confirm the potential of carbosilane dendrimers and dendritic materials as antiviral or antibacterial agents; in therapy against cancer, neurodegenerative disease, or oxidative stress; or many other biomedical applications.This article is categorized under:Nanotechnology Approaches to Biology > Nanoscale Systems in BiologyTherapeutic Approaches and Drug Discovery > Nanomedicine for Infectious DiseaseTherapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic DiseaseMinisterio de Economía y CompetitividadComunidad de MadridJunta de Comunidades de Castilla-La ManchaUniversidad de Alcal

Removing lead from water with carboxylate dendrimers and magnetic nanoparticles modified with carboxylate dendrimers

Contamination of water with heavy metals as lead (Pb2+) is a relevant problematic issue. In this work, we have tested diferent types of dendritic materials for lead removal from water and further recovery. The systems employed are magnetic nanoparticles (MNP) modifed with monocarboxylate and dendritic carboxylate ligands, and they are compared to pristine MNP and carbosilane dendrimers. They are all efective at removing Pb2+, but the key variations are in their recyclability. The usage of a fltering membrane was required for dendrimers, which was signifcantly degraded by the acidic media. In terms of MNP, those that were covered by dendritic molecules were clearly less damaged in acidic media. Finally, isotherm analysis revealed that Pb2+ interacts diferently with unmodifed and modifed MNP.Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER¿BBN)Ministerio de Ciencia e InnovaciónComunidad de MadridUniversidad de Alcal

Helicobacter Species and Hepato-Biliary Tract Malignancies: A Systematic Review and Meta-Analysis

Helicobacter species may cause chronic inflammation of the biliary tract, but its relationship with cancer is controversial. We performed a systematic review and meta-analysis to evaluate the association between Helicobacter species and hepatobiliary tract malignancies. Twenty-six studies (4083 patients) were included in qualitative synthesis, and 18 studies (n = 1895 qualified for meta-analysis. All studies were at high-intermediate risk of bias. Most studies combined several direct microbiological methods, mostly PCR (23 studies), culture (8 studies), and/or CLOtest (5 studies). Different specimens alone or in combination were investigated, most frequently bile (16 studies), serum (7 studies), liver/biliary tissue (8 studies), and gastric tissue (3 studies). Patients with Helicobacter species infection had an increased risk of hepatobiliary tract malignancies (OR = 3.61 [95% CI 2.18–6.00]; p < 0.0001), with high heterogeneity in the analysis (I2 = 61%; p = 0.0003). This effect was consistent when Helicobacter was assessed in bile (OR = 3.57 [95% CI 1.73–7.39]; p = 0.0006), gastric tissue (OR = 42.63 [95% CI 5.25–346.24]; p = 0.0004), liver/biliary tissue (OR = 4.92 [95% CI 1.90–12.76]; p = 0.001) and serum (OR = 1.38 [95% CI 1.00–1.90]; p = 0.05). Heterogeneity was reduced in these sub-analyses (I2 = 0–27%; p = ns), except for liver/biliary tissue (I2 = 57%; p = 0.02). In conclusion, based on low-certainty data, Helicobacter species chronic infection is associated with a tripled risk of hepatobiliary tract malignancy. Prospective studies are required to delineate public health interventions

Bacteria capture with magnetic nanoparticles modified with cationic carbosilane dendritic systems

Bacteria elimination from water sources is key to obtain drinkable water. Hence, the design of systems with ability to interact with bacteria and remove them from water is an attractive proposal. A diversity of polycationic macromolecules has shown bactericide properties, due to interactions with bacteria membranes. In this work, we have grafted cationic carbosilane (CBS) dendrons and dendrimers on the surface of iron oxide magnetic nanoparticles (MNP), leading to NP (ca. 10 nm) that interact with bacteria by covering bacteria membrane. Application of an external magnetic field removes MNP from solution sweeping bacteria attached to them. The interaction of the MNP with Gram-positive S. aureus bacteria is more sensible to the size of dendritic system covering the MNP, whereas interaction with Gramnegative E. coli bacteria is more sensible to the density of cationic groups. Over 500 ppm of NPM, MNP covered with dendrons captured over 90% of both type of bacteria, whereas MNP covered with dendrimers were only able to capture S. aureus bacteria (over 90%) but not E. coli bacteria. Modified MNP were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), Z potential and dynamic light scattering (DLS). Interaction with bacteria was analyzed by UV, TEM and scanning electron microscopy (SEM). Moreover, the possibility to recycle cationic dendronized MNP was explored.Ministerio de Economía, Industria y CompetitividadComunidad de MadridInstituto Ramón y Cajal de Investigación Sanitari

Synthesis of degradable cationic carbosilane dendrimers based on Si-O or ester bonds

Several cationic carbosilane dendrimers have been synthesized containing two different types of degradable bonds: SieO and ester bonds. The first type of systems was prepared by reacting carbosilane dendrimers containing peripheral SieCl bonds with first generation dendrons presenting a eOH function at the focal point and amine peripheral functions. The second type of systems was prepared by esterification between a dendrimer containing acid groups and an alcoholamine. The stability in water of both types of cationic systems was evaluatedMinisterio de Economía y Empres

Potential anti-adhesion activity of novel carbosilane zwitterionic dendrimers against eukaryotic and prokaryotic pathogenic microorganisms

The development of biofilms on different surfaces continues to be a major public health problem. The antimicrobial resistance and the difficulty of finding drugs capable of combating these established biofilms generates the urgent need to find compounds that prevent cells from settling and establishing of these complex communities of microorganisms. Zwitterionic modification of nanomaterials allows the formation of a hydration layer, and this highly hydrophilic surface provides antifouling properties as well as a good biocompatibility by preventing non-specific interactions. Thus, they are appropriate candidates to prevent microbial adhesion to different surfaces and, in consequence, avoid biofilm formation. For this reason, we have incorporated zwitterionic moieties in multivalent systems, as are carbosilane dendrimers. Characterization of these systems was performed using nuclear magnetic resonance and mass spectrometry. It has been analysed if the new molecules have capacity to inhibit the biofilm formation in Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa. The results showed that they were more effective against S. aureus, observing a biofilm reduction of 81.5% treating with 32 mg/L of G2SiZWsf dendrimer and by 72.5% using 32 mg/L of the G3SiZWsf dendrimer. Finally, the absence of cytotoxicity was verified by haemolysis and cytotoxicity studies in human cells lines.Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), SpainMinisterio de Economía, Comercio y EmpresaComunidad de Madri

Anticancer Activity of Dendriplexes against Advanced Prostate Cancer from Protumoral Peptides and Cationic Carbosilane Dendrimers

The interaction of neuropeptides, vasoactive intestinal peptide (VIP), or growth hormone-releasing hormone (GHRH), with a cationic carbosilane dendrimer forms dendriplexes with antitumoral behavior in advanced prostate cancer cells PC3. At the concentrations used for dendriplexes formation, the free peptides were protumoral and prometastatic in advanced prostate cancer, while dendrimer only showed low cytotoxicity, but did not avoid the metastatic behavior of PC3 cells. However, these nanoplexes favored also cell adhesion and avoided cell migration. Also, the dendriplexes were not toxic for no tumoral prostate cells (RPWE-1) or fibroblasts. The use of labeled GHRH peptide (rhodamine labeled) and a dendrimer (fluorescein labeled) allowed us to observe that both systems reach the intracellular milieu after dendriplex formation. The treatment of PC3 cells with the nanoplexes reduced expression of vascular endothelial growth factor (VEGF) and cyclic adenosine monophosphate (CAMP). Molecular modeling analysis highlights the important contribution of the carbosilane framework in the stabilization of the dendriplex, since dendrimer interacts with a peptide region where hydrophobic amino acids are presented.Universidad de AlcaláMinisterio de Economía, Industria y CompetitividadComunidad de MadridInstituto Ramón y Cajal de Investigación Sanitari