59 research outputs found

    Light elements in stars with exoplanets

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    It is well known that stars orbited by giant planets have higher abundances of heavy elements when compared with average field dwarfs. A number of studies have also addressed the possibility that light element abundances are different in these stars. In this paper we will review the present status of these studies. The most significant trends will be discussed.Comment: 10 pages, 6 figures. Submitted to the proceedings of IAU symposium 268: Light elements in the universe

    Antibacterial Effect of Chitosan–Gold Nanoparticles and Computational Modeling of the Interaction between Chitosan and a Lipid Bilayer Model

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    Pathogenic bacteria have the ability to develop antibiotic resistance mechanisms. Their action consists mainly in the production of bacterial enzymes that inactivate antibiotics or the appearance of modifications that prevent the arrival of the drug at the target point or the alteration of the target point itself, becoming a growing problem for health systems. Chitosan–gold nanoparticles (Cs-AuNPs) have been shown as effective bactericidal materials avoiding damage to human cells. In this work, Cs-AuNPs were synthesized using chitosan as the reducing agent, and a systematic analysis of the influence of the synthesis parameters on the size and zeta potential of the Cs-AuNPs and their UV-vis spectra was carried out. We used a simulation model to characterize the interaction of chitosan with bacterial membranes, using a symmetric charged bilayer and two different chitosan models with different degrees of the chitosan amine protonation as a function of pH, with the aim to elucidate the antibacterial mechanism involving the cell wall disruption. The Cs-AuNP antibacterial activity was evaluated to check the simulation model.Fil: Fuster, M.G.. Universidad de Murcia. Facultad de Química; EspañaFil: Montalbán, M. G.. Universidad de Murcia. Facultad de Química; EspañaFil: Carissimi, G.. Universidad de Murcia. Facultad de Química; EspañaFil: Lima, Beatriz Viviana. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Feresin, Gabriela Egly. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Cano, M.. Universidad de Cordoba. Instituto Universitario de Investigación En Química Fina y Nanoquímica.; EspañaFil: Giner Casares, J. J.. Universidad de Cordoba. Instituto Universitario de Investigación En Química Fina y Nanoquímica.; EspañaFil: López Cascales, J.J.. Universidad Politécnica de Cartagena; EspañaFil: Enriz, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Víllora, G.. Universidad de Murcia. Facultad de Química; Españ

    Analysis of the Promoters Involved in Enterocin AS-48 Expression

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    The enterocin AS-48 is the best characterized antibacterial circular protein in prokaryotes. It is a hydrophobic and cationic bacteriocin, which is ribosomally synthesized by enterococcal cells and post-translationally cyclized by a head-to-tail peptide bond. The production of and immunity towards AS-48 depend upon the coordinated expression of ten genes organized in two operons, as-48ABC (where genes encoding enzymes with processing, secretion, and immunity functions are adjacent to the structural as-48A gene) and as-48C1DD1EFGH. The current study describes the identification of the promoters involved in AS-48 expression. Seven putative promoters have been here amplified, and separately inserted into the promoter-probe vector pTLR1, to create transcriptional fusions with the mCherry gene used as a reporter. The activity of these promoter regions was assessed measuring the expression of the fluorescent mCherry protein using the constitutive pneumococcal promoter PX as a reference. Our results revealed that only three promoters PA, P2(2) and PD1 were recognized in Enterococcus faecalis, Lactococcus lactis and Escherichia coli, in the conditions tested. The maximal fluorescence was obtained with PX in all the strains, followed by the P2(2) promoter, which level of fluorescence was 2-fold compared to PA and 4-fold compared to PD1. Analysis of putative factors influencing the promoter activity in single and double transformants in E. faecalis JH2-2 demonstrated that, in general, a better expression was achieved in presence of pAM401-81. In addition, the P2(2) promoter could be regulated in a negative fashion by genes existing in the native pMB-2 plasmid other than those of the as-48 cluster, while the pH seems to affect differently the as-48 promoter expression.This work was supported in part by the Ministerio de Ciencia e Innovación project BIO2008-01708, the Plan Propio from the University of Granada (Spain) and by the Research Plan Group (BIO 160)

    Analysis of the mutational landscape of classic Hodgkin lymphoma identifies disease heterogeneity and potential therapeutic targets

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    Defining the mutational landscape of classic Hodgkin lymphoma is still a major research goal. New targeted next-generation sequencing (NGS) techniques may identify pathogenic mechanisms and new therapeutic opportunities related to this disease. We describe the mutational profile of a series of 57 cHL cases, enriched in Hodgkin and Reed-Sternberg (HRS) cells. Overall, the results confirm the presence of strong genomic heterogeneity. However, several variants were consistently detected in genes related to relevant signaling pathways, such as GM-CSF/IL-3, CBP/EP300, JAK/STAT, NF-kappaB, and numerous variants of genes affecting the B-cell receptor (BCR) pathway, such as BTK, CARD11, BCL10, among others. This unexpectedly high prevalence of mutations affecting the BCR pathway suggests some requirement for active BCR signaling for cHL cell viability. Additionally, incubation of a panel of cHL cellular models with selective BTK inhibitors in vitro constrains cell proliferation and causes cell death. Our results indicate new pathogenic mechanisms and therapeutic opportunities in this disease

    Stratifying diffuse large B-cell lymphoma patients treated with chemoimmunotherapy: GCB/non-GCB by immunohistochemistry is still a robust and feasible marker

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    Diffuse large B cell lymphoma (DLBCL) is a heterogeneous group of aggressive lymphomas that can be classified into three molecular subtypes by gene expression profiling (GEP): GCB, ABC and unclassified. Immunohistochemistry-based cell of origin (COO) classification, as a surrogate for GEP, using three available immunohistochemical algorithms was evaluated in TMA-arranged tissue samples from 297 patients with de novo DLBCL treated by chemoimmunotherapy (R-CHOP and R-CHOP-like regimens). Additionally, the prognostic impacts of MYC, BCL2, IRF4 and BCL6 abnormalities detected by FISH, the relationship between the immunohistochemical COO classification and the immunohistochemical expression of MYC, BCL2 and pSTAT3 proteins and clinical data were evaluated. In our series, non-GCB DLBCL patients had significantly worse progression-free survival (PFS) and overall survival (OS), as calculated using the Choi, Visco-Young and Hans algorithms, indicating that any of these algorithms would be appropriate for identifying patients who require alternative therapies to R-CHOP. Whilst MYC abnormalities had no impact on clinical outcome in the non-GCB subtype, those patients with isolated MYC rearrangements and a GCB-DLBCL phenotype had worse PFS and therefore might benefit from novel treatment approaches

    In-Line estimation of the standard colour index of citrus fruits using a computer vision system developed for a mobile platform

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s11947-012-1015-2A key aspect for the consumer when it comes to deciding on a particular product is the colour. In order to make fruit available to consumers as early as possible, the collection of oranges and mandarins begins before they ripen fully and reach their typical orange colour. As a result, they are therefore subjected to certain degreening treatments, depending on their standard colour citrus index at harvest. Recently, a mobile platform that incorporates a computer vision system capable of pre-sorting the fruit while it is being harvested has been developed as an aid in the harvesting task. However, due to the restrictions of working in the field, the computer vision system developed for this machine is limited in its technology and processing capacity compared to conventional systems. This work shows the optimised algorithms for estimating the colour of citrus in-line that were developed for this mobile platform and its performance is evaluated against that of a spectrophotometer used as a reference in the analysis of colour in food. The results obtained prove that our analysis system predicts the colour index of citrus with a good reliability (R2 = 0.925) working in real time. Findings also show that it is effective for classifying harvested fruits in the field according to their colour. © 2012 Springer Science+Business Media New York.This work was partially funded by the INIA through research project RTA2009-00118-C02-01 with the support of European FEDER funds, and by the project PAID-05-11-2745, Vicerectorat d'Investigacio, Universitat Politecnica de Valencia.Vidal, A.; Talens Oliag, P.; Prats-Montalbán, JM.; Cubero García, S.; Albert Gil, FE.; Blasco Ivars, J. (2013). In-Line estimation of the standard colour index of citrus fruits using a computer vision system developed for a mobile platform. Food and Bioprocess Technology. 6(12):3412-3419. https://doi.org/10.1007/s11947-012-1015-2S34123419612Arzate-Vázquez, I., Chanona-Pérez, J. J., Perea-Flores, M. J., Calderón-Domínguez, G., Moreno-Armendáriz, M. A., Calvo, H., Godoy-Calderón, S., Quevedo, R., & Gutiérrez-López, G. (2011). Image processing applied to classification of avocado variety Hass (Persea americana Mill.) during the ripening process. Food and Bioprocess Technology, 4(7), 1307–1313.Blasco, J., Aleixos, N., Cubero, S., Gómez-Sanchis, J., & Moltó, E. (2009). Automatic sorting of satsuma (Citrus unshiu) segments using computer vision and morphological features. Computers and Electronics in Agriculture, 66, 1–8.Campbell, B. L., Nelson, R. G., Ebel, C. E., Dozier, W. A., Adrian, J. L., & Hockema, B. R. (2004). Fruit quality characteristics that affect consumer preferences for satsuma mandarins. HortScience, 39(7), 1664–1669.Cavazza, A., Corradini, C., Rinaldi, M., Salvadeo, P., Borromei, C., & Massini, R. (2012). Evaluation of pasta thermal treatment by determination of carbohydrates, furosine, and color indices. Food and Bioprocess Technology. doi: 10.1007/s11947-012-0906-6 . In-press.Cubero, S., Aleixos, N., Moltó, E., Gómez-Sanchis, J., & Blasco, J. (2011). Advances in machine vision applications for automatic inspection and quality evaluation of fruits and vegetables. Food and Bioprocess Technology, 4(4), 487–504.Cubero, S., Moltó, E., Gutiérrez, A., Aleixos, N., García-Navarrete, O. L., Juste, F., & Blasco, J. (2010). Real-time inspection of fruit on a mobile harvesting platform in field conditions using computer vision. Progress in Agricultural Engineering Science, 6, 1–16.Díaz, R., Faus, G., Blasco, M., Blasco, J., & Moltó, E. (2000). The application of a fast algorithm for the classification of olives by machine vision. Food Research International, 33, 305–309.DOGV (2006) Diari Oficial de la Comunitat Valenciana, 5346, 30321-30328.Gardner, J. L. (2007). Comparison of calibration methods for tristimulus colorimeters. Journal of Research of the National Institute of Standards and Technology, 112, 129–138.Hashim, N., Janius, R. B., Baranyai, L., Rahman, R. A., Osman, A., & Zude, M. (2011). Kinetic model for colour changes in bananas during the appearance of chilling injury symptoms. Food and Bioprocess Technology, 5(8), 2952–2963.HunterLab (2008): Applications note, 8(9), http://www.hunterlab.com/appnotes/an08_96a.pdf . Accessed September 2012.Hutchings, J. B., Luo, R., & Ji, W. (2002). Calibrated colour imaging analysis of food. In D. MacDougall (Ed.), Colour in Food (pp. 352–366). Cambridge: Woodhead Publishing.Jiménez-Cuesta MJ, Cuquerella J & Martínez-Jávega JM (1981) Determination of a color index for citrus fruit degreening. In Proc. of the International Society of Citriculture, Vol. 2, 750-753Kang, S. P., East, A. R., & Trujillo, F. J. (2008). Colour vision system evaluation of bicolour fruit: A case study with ‘B74’ mango. Postharvest Biology and Technology, 49, 77–85.Lang, C., & Hübert, T. (2011). A colour ripeness indicator for apples. Food and Bioprocess Technology, 5(8), 3244–3249.López-Camelo, A. F., & Gómez, P. A. (2004). Comparison of color indexes for tomato ripening. Horticultura Brasileira, 22(3), 534–537. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-05362004000300006 .López-García, F., Andreu-García, A., Blasco, J., Aleixos, N., & Valiente, J. M. (2010). Automatic detection of skin defects in citrus fruits using a multivariate image analysis approach. 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    Autologous stem-cell transplantation as consolidation of first-line chemotherapy in patients with peripheral T-cell lymphoma : a multicenter GELTAMO/FIL study

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    Peripheral T-cell lymphomas (PTCL) are a heterogeneous group of rare lymphoid malignancies that mostly have poor prognoses with currently available treatments. Upfront consolidation with autologous stem cell transplantation (ASCT) is frequently carried out, but its efficacy has never been investigated in randomized trials. We designed a multicenter, international, retrospective study with the main objective of comparing progression-free survival and overall survival of patients with PTCL who underwent ASCT in complete remission (CR) after first-line chemotherapy with a control group who did not undergo ASCT. From the initial population of 286 registered patients, 174 patients with PTCL other than anaplastic large cell lymphoma, ALK-positive, deemed fit for ASCT at the time of diagnosis, and who were in CR or uncertain CR after induction therapy (CR1) were included in our analysis. one hundred and three patients underwent ASCT, whereas 71 did not, in most cases (n=53) because the physician decided against it. With a median follow-up of 65.5 months, progression-free survival was significantly better in the transplanted patients than in the non-transplanted group: 63% versus 48% at 5 years (P =0.042). Overall survival was significantly longer for ASCT patients in the subgroup with advanced stage at diagnosis (5-year overall survival: 70% vs. 50%, P =0.028). In the multivariate analysis, first-line ASCT was associated with significantly prolonged progression-free survival (HR=0.57, 95% CI: 0.35-0.93) and overall survival (HR=0.57, 95% CI: 0.33-0.99). In conclusion, our study supports the use of ASCT as a consolidation strategy for patients with PTCL in CR1. These results should be confirmed in a prospective randomized study

    Exome sequencing study in patients with multiple sclerosis reveals variants associated with disease course

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    BACKGROUND: It remains unclear whether disease course in multiple sclerosis (MS) is influenced by genetic polymorphisms. Here, we aimed to identify genetic variants associated with benign and aggressive disease courses in MS patients. METHODS: MS patients were classified into benign and aggressive phenotypes according to clinical criteria. We performed exome sequencing in a discovery cohort, which included 20 MS patients, 10 with benign and 10 with aggressive disease course, and genotyping in 2 independent validation cohorts. The first validation cohort encompassed 194 MS patients, 107 with benign and 87 with aggressive phenotypes. The second validation cohort comprised 257 patients, of whom 224 patients had benign phenotypes and 33 aggressive disease courses. Brain immunohistochemistries were performed using disease course associated genes antibodies. RESULTS: By means of single-nucleotide polymorphism (SNP) detection and comparison of allele frequencies between patients with benign and aggressive phenotypes, a total of 16 SNPs were selected for validation from the exome sequencing data in the discovery cohort. Meta-analysis of genotyping results in two validation cohorts revealed two polymorphisms, rs28469012 and rs10894768, significantly associated with disease course. SNP rs28469012 is located in CPXM2 (carboxypeptidase X, M14 family, member 2) and was associated with aggressive disease course (uncorrected p value < 0.05). SNP rs10894768, which is positioned in IGSF9B (immunoglobulin superfamily member 9B) was associated with benign phenotype (uncorrected p value < 0.05). In addition, a trend for association with benign phenotype was observed for a third SNP, rs10423927, in NLRP9 (NLR family pyrin domain containing 9). Brain immunohistochemistries in chronic active lesions from MS patients revealed expression of IGSF9B in astrocytes and macrophages/microglial cells, and expression of CPXM2 and NLRP9 restricted to brain macrophages/microglia. CONCLUSIONS: Genetic variants located in CPXM2, IGSF9B, and NLRP9 have the potential to modulate disease course in MS patients and may be used as disease activity biomarkers to identify patients with divergent disease courses. Altogether, the reported results from this study support the influence of genetic factors in MS disease course and may help to better understand the complex molecular mechanisms underlying disease pathogenesis

    Age and mass of solar twins constrained by lithium abundance

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    We analyze the non-standard mixing history of the solar twins HIP 55459, HIP 79672, HIP 56948, HIP 73815, and HIP 100963, to determine as precisely as possible their mass and age. We computed a grid of evolutionary models with non-standard mixing at several metallicities with the Toulouse-Geneva code for a range of stellar masses assuming an error bar of +-50K in Teff. We choose the evolutionary model that reproduces accurately the observed low lithium abundances observed in the solar twins. Our best-fit model for each solar twin provides a mass and age solution constrained by their Li content and Teff determination. HIP 56948 is the most likely solar-twin candidate at the present time and our analysis infers a mass of 0.994 +- 0.004 Msun and an age of 4.71 +-1.39 Gyr. Non-standard mixing is required to explain the low Li abundances observed in solar twins. Li depletion due to additional mixing in solar twins is strongly mass dependent. An accurate lithium abundance measurement and non-standard models provide more precise information about the age and mass more robustly than determined by classical methods alone.Comment: 10 pages, 5 figures, Accepted for publication in Astronomy and Astrophysic
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