Search results for "Arcos"
showing 10 items of 62 documents
Cylindrical Brush Polymers with Polysarcosine Side Chains: A Novel Biocompatible Carrier for Biomedical Applications
2015
Cylindrical brush polymers constitute promising polymeric drug delivery systems (nanoDDS). Because of the densely grafted side chains such structures may intrinsically exhibit little protein adsorption (“stealth” effect) while providing a large number of functional groups accessible for bioconjugation reactions. Polysarcosine (PSar) is a highly water-soluble, nonionic and nonimmunogenic polypeptoid based on the endogenous amino acid sarcosine (N-methyl glycine). Here we report on the synthesis, characterization and biocompatibility of cylindrical brush polymers with either polysarcosine side chains or poly-l-lysine-b-polysarcosine side chains. The latter leads to block copolypept(o)id based…
Introducing PeptoPlexes: Polylysine-block-Polysarcosine Based Polyplexes for Transfection of HEK 293T Cells
2014
A series of well-defined polypeptide-polypeptoid block copolymers based on the body's own amino acids sarcosine and lysine are prepared by ring opening polymerization of N-carboxyanhydrides. Block lengths were varied between 200-300 for the shielding polysarcosine block and 20-70 for the complexing polylysine block. Dispersity indexes ranged from 1.05 to 1.18. Polylysine is polymerized with benzyloxycarbonyl as well as trifluoroacetyl protecting groups at the ϵ-amine group and optimized deprotection protocols for both groups are reported. The obtained block ionomers are used to complex pDNA resulting in the formation of polyplexes (PeptoPlexes). The PeptoPlexes can be successfully applied i…
Polysarcosine-containing copolymers: Synthesis, characterization, self-assembly, and applications
2018
Although the first polysarcosine (pSar) synthesis by Wesseley et al. was reported almost a century ago, it was only recently that pSar gained broader attention and is considered a potential alternative of poly(ethylene glycol) (PEG). In contrast to polyethers, such as PEG, pSar is a polypeptoid based on the amino acid sarcosine, i.e. N-methylated glycine. As a polymer, pSar combines PEG-like properties, e.g., excellent solubility in water, protein resistance, low cellular toxicity and a non-immunogenic character, while being based on endogenous material. Sarcosine can be obtained in a simple one-step reaction of bromoacetic acid and methylamine, easily transferred into the sarcosine N-(thio…
Synthesis and characterization of bisalkylated polysarcosine-based lipopolymers
2019
The use of PEGylated lipids for the synthesis of stealth liposomes and lipid formulations for nucleic acid delivery has promoted the development of nanoparticle based drugs for cancer therapy, and chronic diseases. Moreover, several other nanomedicines based on these materials have advanced into clinical trails. This enormous success, however, has recently been compromised by the occurrence of immune responses towards PEG, which render pharmacokinetics and can substantially reduce the therapeutic efficiency of drugs. Therefore, alternatives for PEGylated lipids with comparable or even identical solution properties are required. In this work, we report the synthesis of polysarcosine based li…
Die Reaktion von 2-Halogenethoxycarbonyl-Verbindungen mit tertiären Phosphanen
1979
(2-Bromethoxycarbonyl)aminosauren 1, einschlieslich der Sarkosin-Derivate 13 und 15, reagieren mit Methyldiphenylphosphan zu den 2-Phosphonioethoxycarbonyl-Verbindungen, welche unter milden basischen Bedingungen zu den freien Aminoverbindungen gespalten werden. Die gleiche Schutzgruppenumwandlung gelingt an 2-Bromethoxycarbonyl-geschutzten Alkoholen 3. Phenolen 4 und den sekundaren Aminen 11 und 12 sowie an Aminosaure- und Peptid-(2-bromethylestern) nicht. In diesen Fallen bildet sich das Ethylen-1,2-bisphosphoniumsalz 6. Reaction of 2-Haloethoxycarbonyl Compounds with Tertiary Phosphanes (2-Bromoethoxycarbonyl)amino acids 1 including the sarcosine derivatives 13 and 15 react with methyldip…
Análisis del discurso político de Barack H. Obama desde la perspectiva lingüística discursiva de George Lakoff: Elecciones 2008
2015
El objetivo fundamental de esta tesis doctoral es comprobar la viabilidad, adecuación y eficacia de la aplicación de los supuestos de las tesis lingüístico-cognitivas de Lakoff (2002, 2004, 2006, 2007, 2008a, 2008b) al ámbito de los discursos políticos entendidos como construcciones textuales y representaciones del mundo que proponen y defienden, a modo de marcos y a través de unos recursos específicos tal como las metáforas, los partidos políticos (republicano y demócrata) norteamericanos. El paradigma que rige el proceso de investigación puede definirse como lingüístico-cognitivo dentro de la versión específica que desarrolla Lakoff en sus trabajos de carácter propiamente lingüístico y, m…
Recensione Carlo Riggi. Rarefaction
2019
The excessive stereotypical attractiveness and the unreal perfection that the photographs manifest today, especially through social networks, as well as their huge amount, brought it Sicilian psychoanalyst Carlo Riggi to research and communicate with his photographs a way to alienate yourself from an iconic, uncanny invasion
Las percepciones de la exclusión social en el medio rural durante la Gran Recesión: una historia de marcos neoliberales, patriarcales e idilio rural
2022
En este artículo se exploran las percepciones de alcaldes rurales sobre los procesos de exclusión social en sus territorios y los marcos ideológicos que las sostienen. La evidencia empírica de nuestro estudio, contextualizado en España durante la crisis de 2008-2014, procede de entrevistas cualitativas en dos proyectos de investigación sobre exclusión social en áreas rurales de Castilla-La Mancha y la Comunidad Valenciana. Nuestro análisis muestra diferencias significativas entre las descripciones objetivas de exclusión social en el medio rural y cómo se perciben. Los alcaldes responsabilizan de esos procesos a la crisis económica y a las decisiones personales, mientras obvian cualquier res…
Sarcosinaemia in a retarded, amaurotic child.
1986
A 9-month-old Turkish girl demonstrated an abnormal qualitative amino acid excretion pattern suggestive of sarcosinaemia. She was blind and had evidence of developmental and motor retardation. No other physical abnormalities were noted. Quantitative amino acid analysis revealed elevated serum and urine sarcosine levels. An oral sarcosine loading test showed an exaggerated response with a delayed conversion to glycine. Sarcosine was undetected in other family members.
Polysarcosine-Based Lipids: From Lipopolypeptoid Micelles to Stealth-Like Lipids in Langmuir Blodgett Monolayers.
2016
Amphiphiles and, in particular, PEGylated lipids or alkyl ethers represent an important class of non-ionic surfactants and have become key ingredients for long-circulating (“stealth”) liposomes. While poly-(ethylene glycol) (PEG) can be considered the gold standard for stealth-like materials, it is known to be neither a bio-based nor biodegradable material. In contrast to PEG, polysarcosine (PSar) is based on the endogenous amino acid sarcosine (N-methylated glycine), but has also demonstrated stealth-like properties in vitro, as well as in vivo. In this respect, we report on the synthesis and characterization of polysarcosine based lipids with C14 and C18 hydrocarbon chains and their end g…