1,029 research outputs found

    Synthesis of Bioactive Speciosins G and P from Hexagonia speciosa

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    The first total synthesis of speciosins P and G, previously isolated from Hexagonia speciosa, is reported. These compounds have been synthesized by Sonogashira coupling from readily available starting materials. Siccayne was also synthesized from the same starting material in two steps along with a number of other derivatives. The compounds were tested in the wheat coleoptile bioassay. The most active compound was the intermediate 18, followed by 29 and 17. The structural requirements for activity in these compounds are the presence of methoxy groups in the aromatic ring and a formyl or hydroxy group in the side chain

    Ecthyma gangrenosum: a report of eight cases

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    Abstract: Ecthyma gangrenosum is a rare skin infection classically associated with Pseudomonas aeruginosa. We performed a retrospective study of all cases diagnosed with ecthyma gangrenosum from 2004-2010 in a university hospital in Mexico (8 cases, 5 female patients and 3 male patients, ages between 4 months and 2 years). The most common risk factor for ecthyma gangrenosum is neutropenia in immunocompromised patients. In previously healthy patients, immunological evaluation is important to rule out underlying immunodeficiency. Ecthyma gangrenosum in healthy patients has a high mortality rate and early diagnosis and aggressive antibiotic treatment is imperative as it can improve patients’ prognosis. Keywords: Ecthyma; Pseudomonas; Pseudomonas aeruginosa; Pseudomonas infection

    (S)TEM Analysis of the Strain and Morphology of InAs Quantum Dots using GaAs(Sb)(N) Capping Layers for Solar Cell Applications

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    transki-Krastanov In(Ga)As/GaAs quantum dots (QDs) are the subject of great scientific and technological interest, primarily aimed to broaden the emission wavelength towards 1.3-1.55 μm, required for optical fiber telecommunications [1]. More recently, this QD system has drawn a lot of attention owing to their unique properties, which could be also used to boost the energy conversion efficiency of solar cells and exceed the Schockley-Queisser limit [2]. Additionally, the utilization of capping layers (CLs) with materials different than GaAs covering the InAs QDs may provide all these approaches with extra advantages. In this respect, strain-reducing layers (SRLs) such as GaAsSb extend the emission wavelength by reducing the valence band offset while strain compensated layers (SCLs) such as GaAsN CL improve the InAs QD luminescence extending the emission wavelength via conduction band offset reduction, together with a compensation of the compressive strain derived from the InAs QDs. As a consequence, the use of GaAsSbN quaternary alloys as a CL for InAs/GaAs QDs could open even more possibilities allowing independent tailoring of the electron and hole confinement potentials and the strain states of the QDs in a wide range, which could be useful for many applications [3]. However, the nature and the growth conditions of such CLs are critical parameters to determine the resulting properties of the QDs. Processes such as intermixing, segregation or strain-enhanced diffusion could occur during the capping process that modify the shape, composition and strain fields of the QDs [4]. The aim of this study is to compare in a statistical way the effect of several capping materials with different designs and growth conditions of the CL on the morphology of InAs/GaAs QDs

    Strain mapping accuracy improvement using super-resolution techniques

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    Super-resolution (SR) software-based techniques aim at generating a final image by combining several noisy frames with lower resolution from the same scene. A comparative study on high-resolution high-angle annular dark field images of InAs/GaAs QDs has been carried out in order to evaluate the performance of the SR technique. The obtained SR images present enhanced resolution and higher signal-to-noise (SNR) ratio and sharpness regarding the experimental images. In addition, SR is also applied in the field of strain analysis using digital image processing applications such as geometrical phase analysis and peak pairs analysis. The precision of the strain mappings can be improved when SR methodologies are applied to experimental images

    Intercellular Trafficking of Gold Nanostars in Uveal Melanoma Cells for Plasmonic Photothermal Therapy

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    Efficient plasmonic photothermal therapies (PPTTs) using non-harmful pulse laser irradiation at the near-infrared (NIR) are a highly sought goal in nanomedicine. These therapies rely on the use of plasmonic nanostructures to kill cancer cells while minimizing the applied laser power density. Cancer cells have an unsettled capacity to uptake, retain, release, and re-uptake gold nanoparticles, thus offering enormous versatility for research. In this work, we have studied such cell capabilities for nanoparticle trafficking and its impact on the effect of photothermal treatments. As our model system, we chose uveal (eye) melanoma cells, since laser-assisted eye surgery is routinely used to treat glaucoma and cataracts, or vision correction in refractive surgery. As nanostructure, we selected gold nanostars (Au NSs) due to their high photothermal efficiency at the near-infrared (NIR) region of the electromagnetic spectrum. We first investigated the photothermal effect on the basis of the dilution of Au NSs induced by cell division. Using this approach, we obtained high PPTT efficiency after several cell division cycles at an initial low Au NS concentration (pM regime). Subsequently, we evaluated the photothermal effect on account of cell division upon mixing Au NS-loaded and non-loaded cells. Upon such mixing, we observed trafficking of Au NSs between loaded and non-loaded cells, thus achieving effective PPTT after several division cycles under low irradiation conditions (below the maximum permissible exposure threshold of skin). Our study reveals the ability of uveal melanoma cells to release and re-uptake Au NSs that maintain their plasmonic photothermal properties throughout several cell division cycles and re-uptake. This approach may be readily extrapolated to real tissue and even to treat in situ the eye tumor itself. We believe that our method can potentially be used as co-therapy to disperse plasmonic gold nanostructures across affected tissues, thus increasing the effectiveness of classic PPTT

    Synthesis, antibacterial and antifungal activities of naphthoquinone derivatives: a structure–activity relationship study

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    The synthesis of 1,4-naphthoquinone derivatives is of great interest since these compounds exhibit strong activity as antimalarial, antibacterial, antifungal and anticancer agents. A series of 50 naphthoquinone derivatives was synthesized and evaluated for antibacterial and antifungal activity against Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, Candida krusei, Candida parapsilosis and Cryptococcus neoformans using the broth microdilution method. The Candida species were the most susceptible microorganisms. Halogen derivatives of 1,4-naphthoquinone presented strong activity, e.g., 2-bromo-5-hydroxy-1,4-naphthoquinone, which exhibited inhibition at an MIC of 16 lg/ mL in S. aureus, and 2-chloro-5,8-dihydroxy-1,4-naphthoquinone, with an MIC of 2 lg/mL in C. krusei. These compounds showed higher activity against fungi, but the antibacterial activities were very low. The study of structure–activity relationships is very important in the search for new antimicrobial drugs due to the limited therapeutic arsenal

    Tag-SNP analysis of the GFI1-EVI5-RPL5-FAM69 risk locus for multiple sclerosis

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    A recent genome-wide association study conducted by the International Multiple Sclerosis Genetic Consortium (IMSGC) identified, among others, a number of putative multiple sclerosis (MS) susceptibility variants at position 1p22. Twenty-one SNPs positively associated with MS were located at the GFI-EVI5-RPL5-FAM69A locus. In this study, we performed an analysis and fine mapping of this locus, genotyping eight Tag-SNPs in 732 MS patients and 974 controls from Spain. We observed an association with MS in three of eight Tag-SNPs: rs11804321 (P=0.008, OR=1.29; 95% CI1.08-1.54), rs11808092 (P=0.048, OR=1.19; 95% CI1.03-1.39) and rs6680578 (P=0.0082, OR=1.23; 95% CI1.07-1.41). After correcting for multiple comparisons and using logistic regression analysis to test the addition of each SNP to the most associated SNPs, we observed that rs11804321 alone was sufficient to model the association. This Tag-SNP captures two SNPs in complete linkage disequilibrium (r2= 1), both located within the 17th intron of the EVI5 gene. Our findings agree with the corresponding data of the recent IMSGC study and present new genetic evidence that points to EVI5 as a factor of susceptibility to MS. © 2010 Macmillan Publishers Limited All rights reserved.Financial support for the study was provided by the Ministerio de Ciencia e Innovación-Fondos Feder (Grant SAF2009–11491) and Junta de Andalucía (P07-CVI-02551) to A. Alcina, and by Fondo de Investigación Sanitaria (PI081636) to F. Matesanz. María Fedetz is a holder of a fellowship from Fundación IMABIS. Dorothy Ndagire is a holder of AECI-Ministerio de Asuntos Exteriores fellowship.Peer Reviewe

    Evidence‐based treatment for gynoid lipodystrophy: A review of the recent literature

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    Resumen La lipodistrofia ginoide (LDG) es una alteracion estructural, inflamatoria y bioquımica del tejido subcutaneo que causa modificaciones topograficas en la piel. Conocida comunmente como “celulitis”, la LDG afecta hasta a 90% de las mujeres, practicamente en todas las etapas de la vida, iniciando en la pubertad. Se trata de una condicion que afecta considerablemente la calidad de vida de quien la padece. Es motivo frecuente de consulta aunque las pacientes recurren a tratamientos empıricos, improvisados, sin bases ni evidencia cientıfica, los cuales desmotivan y producen frustracion no solo por su falta de resultados, sino por complicaciones derivadas de dichos tratamientos. Un grupo de expertos de diversas especialidades involucradas en el manejo de este problema presenta en este artıculo el resultado de una busqueda bibliografica sistematica y de la discusion consensuada de la evidencia obtenida de diversos tratamientos disponibles actualmente. El analisis se dividio en tratamientos topicos, tratamientos sistemicos, tratamientos no invasivos y tratamientos mınimamente invasivos

    Cuentos del Olivar

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    En este apasionante viaje tenemos las puertas abiertas para todo aquel que se quiera sumar, ya sea trabajando en pos de la difusión de la cultura ligada al olivo o disfrutando de lecturas como las que se recogen en este libro, que seguro les depara un sabroso disfrute y les descubre una cultura del olivar que tiene a sus espaldas varios milenios de historia. Les deseo que paladeen cada uno de estos relatos, que conforman un excelente aperitivo literario.Área de Historia del Art
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