2,835 research outputs found
La cinta blanca de Michael Haneke: poder y represión
A continuación se presenta un estudio sobre la perspectiva que ofrece el director de cine
Michael Haneke en su película “Das Weiße Band” (La cinta blanca) sobre los antecedentes
del nazismo en Alemania. Para ello se realizará al inicio un breve recorrido a través de las
obras del director, en busca de temas recurrentes en su filmografía, que en ocasiones
también encontraremos en “La cinta blanca”, como la violencia y la inocencia de los niños,
la cual Haneke no da por sentada. A continuación serán presentados temas cruciales para el
análisis y comprensión de la película, como el tipo de educación impartida durante la
época Guillermina y las creencias y costumbres transmitidas por la doctrina protestante en
la Alemania rural.
Haneke trata con su película de ofrecer una posible explicación o al menos una perspectiva
diferente e innovadora acerca del periodo precedente al inicio de la Primera Guerra
Mundial, que daría lugar al posterior ascenso del nacionalsocialismo en Alemania. Para
ello cuenta la historia de Eichwald, un ficticio pueblo rural situado en la Alemania del
norte en la época Guillermina en el que comienzan a ocurrir ciertos acontecimientos de
violencia deliberada que atormentan a los ciudadanos. Observaremos como se trata de una
sociedad regida estrictamente por diferentes niveles de poder, en la que se educa a los
niños bajo el yugo de una exigente doctrina protestante que los sitúa en el eslabón más bajo
de la sociedad. Con este argumento y empelando la violencia como elemento central en la
historia, el director Michael Haneke ofrecerá su particular visión sobre la conciencia del
ser humano, la organización de la sociedad, y el tratamiento de la violencia en el cine. En
esta película en blanco y negro, se utilizan técnicas relativamente originales y
experimentales que permiten ejercer una menor influencia sobre el público, para así
llevarlo posteriormente a una reflexión más objetiva
Design and operation of a hybrid power system for Menorca
This project consists on the design of a power system based on renewable sources for the island of Menorca. The main objective of this design is to make the power system of the island as renewable as possible. To do so, there have been selected photovoltaic (PV) and wind power as the main renewable sources, non-renewable sources considered are fuel (case 1) or a cable that connects Menorca to Mallorca and provides energy from the peninsula (case 2), the system will also include batteries. First, there is an energetic study of how much power can be obtained from each source. Then, the methodology used to study the system is by simulation and later optimization. The simulation includes two parts, an energetic and an economic one, and returns the desired parameters given a system configuration defined as the number of PV modules, the number of wind turbines, and the battery capacity in MWh. The energy-based simulation obtains the distribution of power for each source and the % of renewable energy consumed, among others. The economic simulation, inspired by the Levelized Cost of Energy (LCOE), returns the cost per MWh of energy consumed.
The optimization objective is finding the system configuration that provides the highest % of renewable energy and the lowest costs per MWh. To do that there has been used an indicator defined as the cost per MWh divided between the % of renewables, and to minimize it. There has been established a maximum of exceeding energy (that is produced in excess and won’t be used), and stability restrictions are not taken into account. After that, there has been carried out a sensitivity analysis to know how the results obtained previously may change in the future according to the cost trends of the sources.
Results show that the % of renewables is in all situations more than 60%, the exact value and the average cost of generation depends on the costs of all the components of the system. When the non-renewable source is much more expensive than the renewables, the average cost increases and the % of renewables also highly increases; while when costs of renewables and non-renewables are more similar, it led to situations with lower average costs and lower penetration of renewables. Future situations predict an increase in the % of renewables, and in most of the cases the average costs will be reduced
Design and operation of multiport converters for distribution systems
Electrical power distribution systems are experiencing an increase in renewable energy integra- tion, which is reversing the power flow during some periods and modifying their conventional operation. In this context, the curtailment of renewable distributed generation is needed to consider the electrical limitations of transformers and lines, which are mainly voltage devia- tions and power overloads. Multiport converters (MPC) with energy storage are presented as a potential solution for enhancing power flow operation in the distribution system and minimiz- ing renewable generation curtailments. Alternatively, adding energy storage systems (ESS), switches, soft open points, and new lines can also be considered. This Master’s Thesis presents an optimisation-based methodology to size multiport power con- verters. The methodology is divided into three steps: days selection of the load and renewable resource availability profiles, storage sizing, and multiport converter sizing optimisation. The MPC sizing optimisation considers the days selected previously instead of the whole year, in- cludes electrical constraints, and also optimises the system operation. This methodology also provides technical and economic indicators for a complete evaluation of the multiport converter integration. The general methodology is evaluated in a case study based on a medium voltage benchmark network from CIGRE. The multiport converter solution is compared to alternative configura- tions with separated batteries and a simple switch interconnection, it also considers different penetrations of renewable energy. Additionally, a sensitivity analysis of economic parameters is performed on the optimisation. Overall, the objective is to identify the best scenarios where multiport converters can be considered as a potential solution. The results conclude that the rated power of the multiport converter terminals used to exchange power between different feeders is sized as the nominal power of the lines and transformers in scenarios with unbalanced distributed generation in the feeders. Whereas in scenarios with bal- anced distributed generation, the size of the rated power of the multiport converter terminals is lower and has more variability. As a general conclusion, the results show that the multiport converter can reduce power curtailment in equivalent terms or even better than battery solu- tions, especially in scenarios with unbalanced distributed generation in the feeders. With high penetration of renewables, all scenarios studied are economically feasible to install a multiport converter. Scenarios with unbalanced generation remain feasible if the renewable generation capacity is reduced, unless batteries are initially installed in the feeders. In general, for all sce- narios, a multiport converter with a centralised battery is the best option
A Deep Learning Approach to generate Beethoven's 10th Symphony
Luidwig van Beethoven composed his symphonies between 1799 and 1825, when he was writing his Tenth symphony. As we dispose of a great amount of data belonging to his work, the purpose of this project is to work on the possibility of extracting patterns on his compositional model and generate what would have been his last symphony, the Tenth.
Computational creativity is an Artificial Intelligence field which is still being developed. One of its subfields is music generation, to which this project belongs. Also, there is an open discussion about the belonging of the creativity, to the machine or the programmer.
Firstly we have extracted all the symphonies' scores information, structuring them by instrument. Then we have used Deep Learning techniques to extract knowledge from the data and later generate new music. The neural network model is built based on the Long Short-Therm Memory (LSTM) neural networks, which are distinguished from others since these ones contain a memory module. After training the model and predict new scores, the generated music has been analyzed by comparing the input data with the results, and establishing differences between the generated outputs based on the training data used to obtain them. The result's structure depends on the symphonies used for training, so obtained music presents Beethoven's style characteristics
Cellular basis of pineal gland development: Emerging role of microglia as phenotype regulator
The adult pineal gland is composed of pinealocytes, astrocytes, microglia, and other interstitial cells that have been described in detail. However, factors that contribute to pineal development have not been fully elucidated, nor have pineal cell lineages been well characterized. We applied systematic double, triple and quadruple labeling of cell-specific markers on prenatal, postnatal and mature rat pineal gland tissue combined with confocal microscopy to provide a comprehensive view of the cellular dynamics and cell lineages that contribute to pineal gland development. The pineal gland begins as an evagination of neuroepithelium in the roof of the third ventricle. The pineal primordium initially consists of radially aligned Pax6+ precursor cells that express vimentin and divide at the ventricular lumen. After the tubular neuroepithelium fuses, the distribution of Pax6+ cells transitions to include rosette-like structures and later, dispersed cells. In the developing gland all dividing cells express Pax6, indicating that Pax6+ precursor cells generate pinealocytes and some interstitial cells. The density of Pax6+ cells decreases across pineal development as a result of cellular differentiation and microglial phagocytosis, but Pax6+ cells remain in the adult gland as a distinct population. Microglial colonization begins after pineal recess formation. Microglial phagocytosis of Pax6+ cells is not common at early stages but increases as microglia colonize the gland. In the postnatal gland microglia affiliate with Tuj1+ nerve fibers, IB4+ blood vessels, and Pax6+ cells. We demonstrate that microglia engulf Pax6+ cells, nerve fibers, and blood vessel-related elements, but not pinealocytes. We conclude that microglia play a role in pineal gland formation and homeostasis by regulating the precursor cell population, remodeling blood vessels and pruning sympathetic nerve fibers.Fil: Ibañez Rodriguez, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Noctor, Stephen C.. University of California; Estados UnidosFil: Muñoz, Estela Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin
Neisseria gonorrhoeae challenge increases matrix metalloproteinase-8 expression in fallopian tube explants
Indexación: Scopus.Background: Neisseria gonorrhoeae (Ngo) is the etiological agent of gonorrhea, a sexually transmitted infection that initially infects the female lower genital tract. In untreated women, the bacteria can ascend to the upper genital reproductive tract and infect the fallopian tube (FTs), which is associated with salpingitis and can lead to impaired FT function and infertility. The extracellular matrix (ECM) plays an important role in cell migration and differentiation in the female genital tract, and some pathogens modify the ECM to establish successful infections. The ECM is regulated by matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs), their endogenous inhibitors; MMP deregulation causes pathological conditions in a variety of tissues. Results: The aim of this work was to analyze the expression and localization of MMP-3, MMP-8, MMP-9, and TIMP-1 in FT explants during Ngo infection using real-time PCR, immunohistochemistry, zymography and ELISA. No significant variations in MMP-3, MMP-9, and TIMP-1 transcript levels were observed. In contrast, a significant increase (p < 0.05) was observed for MMP-8 expression and was accompanied by stromal immunoreactivity in infected explants. ELISA results supported these findings and showed that MMP-8 release increased upon gonococcal infection. Conclusions: Our results indicate that gonococcal infection induces increased MMP-8 expression, which might contribute to FT damage during infection. © 2017 Juica, Rodas, Solar, Borda, Vargas, Muñoz, Paredes, Christodoulides and Velasquez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00399/ful
Synthesis of Biologically Active Glycosylphosphatidylinositol Derivatives Bearing Unsaturated Lipids
Several eukaryotic proteins are attached to the cell membrane using glycosylphosphatidylinositol (GPI) anchors, a family of complex glycolipids. GPIs are post-translationally added to the C-terminus of proteins and contain a conserved pseudopentasaccharide glycan core structure, a phosphoethanolamine (PEtN) unit, and a phospholipid. Deficiencies in the GPI-anchored proteins (GPI-APs) biosynthesis lead to a series of rare and complicated disorders associated with inherit-ed GPI deficiencies (IGDs) in humans. Currently, there is no treatment for patients suffering from IGDs, and there is a lack of understanding of the biological events derived from the GPI deficien-cy.
Deciphering the GPIs biological functions and the application of these molecules as tools in chem-ical biology require homogeneous samples. GPIs are naturally found as heterogeneous mixtures that are difficult to separate for getting single compounds in pure form. Several strategies have been reported to obtain pure GPIs by chemical synthesis; nevertheless, incorporating unsaturated fatty acids remains challenging. GPIs and GPI fragments containing unsaturated lipids are not only predominant intermediates during the GPI biosynthesis but are also highly present on the cell surface of protozoan parasites and exhibit prominent proinflammatory activity. Thus, developing a reliable strategy to access these complex glycolipids is of great interest.
This work aimed to develop a general and convergent synthesis of GPIs bearing unsaturated li-pids. In previous work, our group established a strategy using 2-naphthylmethyl (Nap) ether as permanent protection for incorporating unsaturated lipids in a GPI derivative synthesis. In this work, the process was expanded and optimized to get biologically active and structurally diverse GPIs and GPI fragments containing unsaturated fatty acid chains.
In the first part of this work, nine GPI fragments resembling the products of the initial steps of the GPI biosynthesis (Figure 1) were designed and synthesized to determine the activity of syn-thetic GPI-glycolipids in restoring the GPI-APs biosynthesis in GPI-AP deficient cells (chapter 2).
Glycolipids 1, 2, and 3 were synthesized by assembling first the glycan part using Nap-protected inositol, glucosamine, and mannose building blocks. The lipids were installed at the late synthesis stage before the global deprotection. Removal of the Nap ethers was optimized and successfully performed under oxidative conditions with DDQ. Pure compounds were purified by size exclusion chromatography and trituration in methanol. The glycolipids were biologically evaluated at Osaka University to determine the activity of the synthetic fragments to rescue the GPI-APs production in GPI-AP deficient HEK cells having knockout genes involved in the first four steps of GPI biosyn-thesis.
The biological assays demonstrated that the synthetic fragments 1a, 2a, 2b, and 3 rescue the GPI biosynthesis in HEK cells having PIGA or PIGL knockout genes in vitro. The glycolipids showed concentration-dependent recovery of GPI biosynthesis and were highly active on the steps at the ER's cytoplasmic face. However, the synthetic compounds could not restore the biosynthesis pro-cess in cells having knock-out genes affecting the steps on the luminal side of the ER. The activity absence was attributed to the lack of compounds transport across the ER membrane.
A set of biological studies using glycolipids 1b, 1c, 1d, 2c, and 2d are in progress to determine the transport mechanisms for incorporating GPI fragments in the knockout cells and to evaluate the lipid influence on the fragments’ incorporation into the GPI biosynthesis. Compounds 1b and 2c were synthesized without unsaturated lipids to disclose the role of unsaturation in the activity; fragments 1c and 2d were designed to evaluate the effect of alkyl and acyl chains on compound activity. Additionally, the azide-labeled fragment 1d was synthesized to analyze the transport of the compounds inside the cells.
Altogether, this work showed the application of a synthetic strategy to obtain active GPI fragments and their suitability as tools for future development of glycan-based treatments of IGDs involving mutations in the PIGA and PIGL genes. Additional studies are required to expand the structure-activity relationship understanding, tune the activity of the glycolipids, and establish methods for efficient GPI fragments delivery into the ER Lumen to cover mutations in genes affecting further steps of the GPI-AP biosynthesis.
In the second part of this work, the synthetic strategy was expanded for the total synthesis of a GPI of Plasmodium falciparum—the parasite that causes Malaria—having unsaturated lipids (chapter 3). The strategy was based on using Nap ether protecting groups, the global deprotec-tion developed for the synthesis of GPI fragments 1 to 3, and a previous strategy to access GPIs with saturated lipids. The assembly of the GPI glycan core relied on a set of fully orthogonally protected building blocks 4 to 7 that enabled the regioselective introduction of phosphodiesters at the late synthesis stage (Scheme 1). Mannose building blocks 4, 5 and 9 were equipped with an allyl protecting group on the anomeric position that was converted into a trichloroacetimidate to perform the glycosylation reactions. The stereoselectivity of glycosylations was controlled by the reaction conditions and neighboring group participation of the levulinoyl and acetyl esters, deliver-ing the desired α configuration.The assembly of the glycan core via a [3+2] glycosylation was followed by the introduction of the phospholipid using H-phosphonate 11 and a two-step phosphorylation with H-phosphonate 8a to introduce the PEtN unit. A three-step protocol was performed for global deprotection to furnish the desired P. falciparum GPI 12a bearing unsaturated lipids. Additionally, the GPI 12b was synthe-sized using H-phosphonate 8b to incorporate a protected cysteine attached to phosphoethanola-mine in the second phosphorylation. The cysteine in GPI 12b allows the coupling with a protein through native chemical ligation to obtain a GPI-AP.
In the third part of this work, the strategy was applied to synthesize a GPI of the parasite Tryp-anosoma cruzi, the causing agent of Chagas disease (chapter 4). The synthesis required a modi-fied strategy to incorporate two GPI-glycan modifications: an additional mannose attached to the Man-III unit and an aminoethylphosphonate (AEP) unit attached to glucosamine (Scheme 2). The process required an additional mannose unit into the glycan that was incorporated using [4+2] glycosylation strategy instead of [3+2]. The lipidated pseudohexasaccharide 18 was synthesized using the same route used for synthesizing the P. falciparum GPI and involved a phosphorylation using the H-phosphonate 16. An extra level of orthogonality was achieved by including a PMB protecting group at the O-6 position of glucosamine at an early stage of the route. This differenti-ated position in the pseudodisaccharide 15 was selectively deprotected to incorporate the AEP component, a characteristic modification of T. cruzi GPIs. The attachment of the AEP moiety was more challenging than expected. Attempts to optimize this reaction with a small model molecule presented unexpected results for the NMR and Mass spectra, so additional studies are still re-quired to achieve the desired transformation and complete the synthesis. Further steps include the phosphorylation using the H-phosphonate 8a to obtain the final protected T. cruzi GPI, which can be transformed into the final target 19 using the three-step deprotection protocol established to get GPI 12.
This work established a general approach for synthesizing diverse GPIs and GPI fragments bear-ing unsaturated lipids. The developed strategy allows not only to produce homogeneous native GPI structures but also provides the flexibility to accommodate further modifications to give un-natural analogs. Access to these complex glycolipids will enable extensive investigation into their biological roles and expand their potential applications in biomedical research.Viele eukaryotische Proteine sind mittels einer Stoffklasse komplexer Glykolipide, den Glykosylphos-phatidylinositol(GPI)-Ankern, an die Zellmembran gebunden. Alle GPIs bestehen aus einer Pseudopen-tasaccharid-Glykan-Kernstruktur, einer Phosphoethanolamin(PEtN)-Einheit und einem Phospholipid. Die GPIs werden posttranslational an den C Terminus von Proteinen angeknüpft. Mängel in der Biosynthese von GPI-verankerten Proteinen (GPI-APs) führen zu einer Reihe seltener und komplizierter Erkrankun-gen, die mit vererbten GPI-Mangelzuständen (IGD, für das englische Acronym „inherited GPI deficien-cies“) beim Menschen verbunden sind. Derzeit gibt es keine Behandlungsmöglichkeiten von Patienten, die an IGDs leiden. Zusätzlich sind die biologischen Prozesse, die aus einem GPI-Mangel resultieren, nicht ausreichend erforscht und verstanden.
Für die Entschlüsselung der biologischen Funktionen von GPIs und deren Verwendung als Werkzeuge in der chemischen Biologie werden homogenen Proben benötigt. GPIs können in der Natur aber ledig-lich als heterogene Mischungen gefunden werden. Es ist äußerst schwierig die einzelnen GPIs vonei-nander zu trennen, was es herausfordernd macht einzelne Verbindungen in reiner Form zu erhalten. Einige Strategien zur chemischen Synthese von reinen, homogenen GPIs wurden bereits veröffentlicht, jedoch stellt die Synthese von GPIs mit ungesättigten Fettsäuren nach wie vor eine große Herausforde-rung dar. GPIs und GPI-Fragmente mit ungesättigten Lipiden sind nicht nur wichtige Intermediate wäh-rend der GPI-Biosynthese, sie kommen auch zahlreich auf der Zelloberfläche von Protozoen-Parasiten vor und zeigen eine herausragende proinflammatorische Eigenschaft. Daher ist die Entwicklung einer zuverlässigen Synthesestrategie, die Zugang zu diesen komplexen Glykolipiden schafft, von großer Bedeutung.
Das Ziel dieser Arbeit bestand darin eine allgemeine und konvergente Synthesestrategie von GPIs mit ungesättigten Lipiden zu entwickeln. In vergangenen Arbeiten hat unsere Gruppe eine Strategie entwi-ckelt, bei der 2-Naphthylmethyl(Nap)-Ether als permanente Schutzgruppen zur Einführung ungesättigter Lipide in die Synthese von GPI-Derivaten verwendet wurden. Im Rahmen dieser Arbeit wurde der Pro-zess erweitert und optimiert, um biologisch aktive und strukturell vielseitige GPIs und GPI-Fragmente mit ungesättigten Fettsäureketten zugänglich zu machen.
Im ersten Teil dieser Arbeit wurden neun GPI-Fragmente, welche den Produkten der ersten Schritte der GPI-Biosynthese ähneln, entworfen und synthetisiert (Figur 1). Mit diesen Fragmenten sollte die Aktivität synthetischer GPI-Glykolipide bei der Wiederherstellung der GPI-APs-Biosynthese in GPI-AP-defizienten Zellen bestimmt werden (Kapitel 2).
Die Glykolipide 1, 2 und 3 wurden beginnend mit dem Aufbau der Glykan-Kernstruktur durch Verwen-dung von Nap-geschützten Inositol-, Glucosamin- und Mannose-Bausteinen erreicht. Die Lipide wurden gegen Ende der Synthesesequenz vor der vollständigen Entschützung der Glykolipide eingeführt. Die Abspaltung der Nap-Ether wurde optimiert und erfolgreich unter oxidativen Bedingungen mittels DDQ bewerkstelligt. Die reinen Verbindungen wurden durch Größenausschlusschromatographie und Tritura-tion in Methanol erhalten. Die Glykolipide wurden an der Universität Osaka biologisch bewertet, bezogen auf deren Aktivität zur Rettung der GPI-AP-Produktion in GPI-AP-defizienten HEK-Zellen mit Knockout-Genen, die an den ersten vier Schritten der GPI-Biosynthese beteiligt sind.
Die biologischen Assays zeigten, dass die synthetischen Fragmente 1a, 2a, 2b und 3 die GPI-Biosynthese in vitro in HEK-Zellen mit PIGA- oder PIGL-Knockout-Genen retten. Die Glykolipide zeigten eine konzentrationsabhängige Wiederherstellung der GPI-Biosynthese und waren hochaktiv in den Stu-fen an der zytoplasmatischen Seite des ER. Die synthetischen Verbindungen konnten jedoch nicht den Biosyntheseprozess in Zellen mit Knock-out-Genen wiederherstellen, die die Schritte auf der luminalen Seite des ER beeinflussen. Das Fehlen der Aktivität wurde auf den mangelnden Transport der Moleküle durch die ER-Membran zurückgeführt.
Eine Reihe biologischer Studien mit den Glykolipiden 1b, 1c, 1d, 2c und 2d sind im Gange, um die Transportmechanismen für die Aufnahme von GPI-Fragmenten in die Knockout-Zellen zu bestimmen und den Einfluss der Lipide auf den Einbau der Fragmente in die GPI-Biosynthese zu bewerten. Die Ver-bindungen 1b und 2c wurden ohne ungesättigte Lipide synthetisiert, um die Rolle der Ungesättigtheit bezogen auf die Aktivität der Moleküle herauszufinden. Die Fragmente 1c und 2d wurden entwickelt, um die Wirkung von Alkyl- und Acylketten auf die Aktivität der Moleküle zu testen. Zusätzlich wurde das Azid-markierte Fragment 1d synthetisiert, um den Transport der Verbindungen innerhalb der Zellen ver-folgen zu können.
Zusammenfasend zeigte diese Arbeit die Anwendung einer synthetischen Strategie, um biologisch akti-ve GPI-Fragmente herzustellen, und deren Eignung als Hilfsmittel für zukünftige Entwicklungen glykan-basierter Behandlungen von IGDs mit Mutationen in den PIGA- und PIGL-Genen. Zusätzliche Studien sind erforderlich, um das Verständnis der Struktur-Aktivitäts-Beziehung zu verbessern, die Aktivität der Glykolipide einstellen zu können, und Methoden für die effiziente Aufnahme von GPI-Fragmenten in das ER-Lumen zu etablieren, um Mutationen in Genen abdecken zu können, die weitere Schritte der GPI-AP-Biosynthese beeinflussen.
Im zweiten Teil dieser Arbeit wurde die Synthesestrategie für die Totalsynthese eines GPI von Plas-modium falciparum – dem Parasiten, der Malaria verursacht – mit ungesättigten Lipiden erweitert (Kapi-tel 3). Die Strategie basiert auf der Verwendung von Nap-Ether-Schutzgruppen, der globalen Entschüt-zung, die für die Synthese der GPI-Fragmente 1-3 entwickelt wurde, und einer früheren Strategie, wel-che Zugang zu GPIs mit gesättigten Lipiden liefert. Für den Aufbau des GPI-Glykan-Kerns wurde eine Kombination aus den vollständig orthogonal geschützten Bausteine 4 bis 7 verwendet, welche die regio-selektive Einführung von Phosphodiestern im späten Verlauf der Synthese ermöglichten (Schema 1). Die Mannose-Bausteine 4, 5 und 9 wurden mit einer Allyl-Schutzgruppe am anomeren Zentrum verse-hen, die mittels Entschützung und anschließender Funktionalisierung in eine Trichloracetimidat-Gruppe umgewandelt wurde, um die Glykosylierungsreaktionen durchführen zu können. Die Stereoselektivität der Glykosylierungen wurde durch geeignete Reaktionsbedingungen und den Nachbargruppen-Effekt der Lävulinsäure- und Acetylester gesteuert. Dadurch wurde die gewünschte α-Konfiguration erzielt.
Nach dem Aufbau des Glykan-Kerns mittels [3+2]-Glykosylierung folgte die Anknüpfung des Phospholi-pids durch H-Phosphonat 11 und eine zweistufige Phosphorylierung mit H-Phosphonats 8a zur Einfüh-rung der PEtN-Einheit. Um das gewünschte GPI 12a aus P. falciparum mit ungesättigten Lipiden bereit-zustellen, wurde eine dreistufige Synthesesequenz zur globalen Entschützung verwendet. Zusätzlich wurde das GPI 12b unter Verwendung von H-Phosphonat 8b synthetisiert, um bei der zweiten Phospho-rylierung ein an das Phosphoethanolamin gebundenes, geschütztes Cystein in das Molekül einbauen zu können. Das Cystein in GPI 12b ermöglicht die Kupplung mit einem Protein durch native chemische Ligation, wodurch ein GPI-AP erhalten werden kann.
Im dritten Teil dieser Arbeit wurde diese Strategie auf die Synthese eines GPI des Parasiten Trypa-nosoma cruzi – dem Erreger der Chagas-Krankheit – übertragen (Kapitel 4). Die Synthese benötigte eine angepasste Strategie, um zwei GPI-Glykan-Modifikationen einzubauen: Einen zusätzlichen Manno-se-Baustein, der an die Man-III-Einheit gebunden ist, und eine Aminoethylphosphonat(AEP)-Einheit, die an das Glucosamin gebunden ist (Schema 2). Das lipid-modifizierte Pseudohexasaccharid 18 wurde nach der Synthesestrategie des P. falciparum GPI hergestellt. Die [3+2]-Glykosylierungsstrategie wur-de in diesem Fall zu einer [4+2]-Glykosylierungsstrategie geändert, um eine zusätzliche Mannose-Einheit in das Glykan einzubauen. Die Phospholipid-Einheit wurde durch Verwendung des H-Phosphonats 16 eingeführt. Durch das Anknüpfen einer PMB-Schutzgruppe an die O-6-Position des Glucosamins am Anfang der Syntheseroute wurde eine zusätzliche Orthogonalitätsstufe gewonnen. Diese Position wurde im Pseudodisaccharid 15 selektiv entschützt, um die AEP-Komponente, eine cha-rakteristische Modifikation von T. cruzi-GPIs, anzubringen. Die Anknüpfung der AEP-Einheit erwies sich jedoch schwieriger als erwartet. Diese Reaktion wurde an einem kleinen Modellmolekül getestet bzw. optimiert, wobei die Transformation nicht eindeutige NMR- und Massenspektren lieferte. Deshalb wer-den hier noch weitere Studien benötigt, um die gewünschte Modifikation erreichen und die Synthese abschließen zu können. Diese Schritte umfassen die Phosphorylierung unter Verwendung des H Phosphonats 8a, um das finale, geschützte T. cruzi-GPI zu erhalten. Dieses kann gemäß dem drei-stufigen Entschützungsprotokoll, das sich bei der Synthese von GPI 12 bewährt hat, zum Zielmolekül 19 umgesetzt werden.
Diese Arbeit etablierte einen allgemeinen Ansatz zur Synthese verschiedener GPIs und GPI-Fragmente mit ungesättigten Lipiden. Die entwickelte Strategie ermöglicht nicht nur die Herstellung homogener nativer GPI-Strukturen, sondern bietet auch die Flexibilität weitere Modifikationen vorzunehmen, um unnatürliche Analoga herzustellen. Der Zugang zu diesen komplexen Glykolipiden ermöglicht es ihre biologische Funktion genauer zu untersuchen und ihre potenziellen Anwendungen in der biomedizini-schen Forschung zu überprüfen
Deep Spatiotemporal Model for COVID-19 Forecasting
COVID-19 has caused millions of infections and deaths over the last 2 years. Machine
learning models have been proposed as an alternative to conventional epidemiologic models in
an effort to optimize short- and medium-term forecasts that will help health authorities to optimize
the use of policies and resources to tackle the spread of the SARS-CoV-2 virus. Although previous
machine learning models based on time pattern analysis for COVID-19 sensed data have shown
promising results, the spread of the virus has both spatial and temporal components. This manuscript
proposes a new deep learning model that combines a time pattern extraction based on the use of
a Long-Short Term Memory (LSTM) Recurrent Neural Network (RNN) over a preceding spatial
analysis based on a Convolutional Neural Network (CNN) applied to a sequence of COVID-19
incidence images. The model has been validated with data from the 286 health primary care centers
in the Comunidad de Madrid (Madrid region, Spain). The results show improved scores in terms
of both root mean square error (RMSE) and explained variance (EV) when compared with previous
models that have mainly focused on the temporal patterns and dependencies.This work is part of the agreement between the Community of Madrid and the Universidad
Carlos III de Madrid for the funding of research projects on SARS-CoV-2 and COVID-19 disease,
project name “Multi-source and multi-method prediction to support COVID-19 policy decision
making”, which was supported with REACT-EU funds from the European regional development
fund “a way of making Europe”. This work was supported in part by the projects “ANALISIS
EN TIEMPO REAL DE SENSORES SOCIALES Y ESTIMACION DE RECURSOS PARA TRANSPORTE
MULTIMODAL BASADA EN APRENDIZAJE PROFUNDO” MaGIST-RALES, funded by the
Spanish Agencia Estatal de Investigación (AEI, doi: 10.13039/501100011033) under grant PID2019-
105221RB-C44/AEI/10.13039/501100011033 and “FLATCITY-APP: Aplicación móvil para FlatCity”
funded by the Spanish Ministerio de Ciencia e Innovación and the Agencia Estatal de Investigación
MCIN/AEI/10.13039/501100011033 and the European Union “NextGenerationEU/PRTR” under
grant PDC2021-121239-C33
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