Discovery of a wide companion near the deuterium burning mass limit in the Upper Scorpius association

We present the discovery of a companion near the deuterium burning mass limit located at a very wide distance, at an angular separation of 4.6+/-0.1 arcsec (projected distance of ~ 670 AU) from UScoCTIO108, a brown dwarf of the very young Upper Scorpius association. Optical and near-infrared photometry and spectroscopy confirm the cool nature of both objects, with spectral types of M7 and M9.5, respectively, and that they are bona fide members of the association, showing low gravity and features of youth. Their masses, estimated from the comparison of their bolometric luminosities and theoretical models for the age range of the association, are 60+/-20 and 14^{+2}_{-8} MJup, respectively. The existence of this object around a brown dwarf at this wide orbit suggests that the companion is unlikely to have formed in a disk based on current planet formation models. Because this system is rather weakly bound, they did not probably form through dynamical ejection of stellar embryos.Comment: 10 pages, including 4 figures and 2 table

Hybrid Catalysts Comprised of Graphene Modified with Rhodium-Based N-Heterocyclic Carbenes for Alkyne Hydrosilylation

Thermally partially reduced graphene oxide has been covalently modified with 3-methyl-4-phenyl-1, 2, 3-triazolium salts making use of the epoxy functionalities on the carbon nanomaterial. Characterization of the functionalized materials through adequate solid characterization techniques, particularly X-ray photoelectron spectroscopy (XPS), allows one to follow the stepwise building up of the triazolium fragments on the graphene oxide attached to the wall via covalent C-N linkage. The hydroxyl-triazolium-functionalized materials have been used to prepare rhodium hybrid materials containing either alkoxo or triazolylidene molecular rhodium(I) complexes depending on the protection of the hydroxyl groups present in the material. Characterization of the heterogeneous systems, especially by means of XPS and extended X-ray absorption fine structure (EXAFS) spectroscopy, has evidenced the coordination sphere of the supported rhodium(I) complexes in both rhodium hybrid materials. The graphene-oxide-supported rhodium triazolylidene hybrid catalysts show excellent activity, comparable to that of the homogeneous [RhI(cod)(Triaz)] (Triaz = 1, 4-diphenyl-3-methyl-1, 2, 3-triazol-5-ylidene) catalyst, for the hydrosilylation of terminal and internal alkynes. In addition, these catalysts have shown good selectivity to the beta-(Z) vinylsilane isomers (for the not hindered terminal substrates) or syn-additions (for the internal substrates). In contrast to the rhodium(I)-alkoxo-based hybrid material, the silyl-protected rhodium(I)-triazolylidene-based hybrid catalyst can be reused in consecutive cycles without loss of activity maintaining the selectivity. The lack of leaching of active rhodium species demonstrates the strength of the C-N covalent bond of the triazolylidene linker to the graphitic wall

Water Splitting Electrocatalysis within Layered Inorganic Nanomaterials

The conversion of solar energy into chemical fuel is one of the “Holy Grails” of twenty-first century chemistry. Solar energy can be used to split water into oxygen and protons, which are then used to make hydrogen fuel. Nature is able to catalyze both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) required for the conversion of solar energy into chemical fuel through the employment of enzymes that are composed of inexpensive transition metals. Instead of using expensive catalysts such as platinum, cheaper alternatives (such as cobalt, iron, or nickel) would provide the opportunity to make solar energy competitive with fossil fuels. However, obtaining efficient catalysts based on earth-abundant materials is still a daunting task. In this chapter, we review the advancements made with zirconium phosphate (ZrP) as a support for earth-abundant transition metals for the OER. Our studies have found that ZrP is a suitable support for transition metals as it provides an accessible surface where the OER can occur. Further findings have also shown that exfoliation of ZrP increases the availability of sites where active species can be adsorbed and performance is improved with this strategy

Bergamot natural products eradicate cancer stem cells (CSCs) by targeting mevalonate, Rho-GDI-signalling and mitochondrial metabolism

Here, we show that a 2:1 mixture of Brutieridin and Melitidin, termed “BMF”, has a statin-like properties, which blocks the action of the rate-limiting enzyme for mevalonate biosynthesis, namely HMGR (3-hydroxy-3-methylglutaryl- CoA-reductase). Moreover, our results indicate that BMF functionally inhibits several key characteristics of CSCs. More specifically, BMF effectively i) reduced ALDH activity, ii) blocked mammosphere formation and iii) inhibited the activation of CSC-associated signalling pathways (STAT1/3, Notch and Wnt/ beta-catenin) targeting Rho-GDI-signalling. In addition, BMF metabolically inhibited mitochondrial respiration (OXPHOS) and fatty acid oxidation (FAO). Importantly, BMF did not show the same toxic side-effects in normal fibroblasts that were observed with statins. Lastly, we show that high expression of the mRNA species encoding HMGR is associated with poor clinical outcome in breast cancer patients, providing a potential companion diagnostic for BMF-directed personalized therapy

Strategies of statistical windows in PET image reconstruction to improve the user s real time experience

[EN] Nowadays, with the increase of the computational power of modern computers together with the state-of-the-art reconstruction algorithms, it is possible to obtain Positron Emission Tomography (PET) images in practically real time. These facts open the door to new applications such as radio-pharmaceuticals tracking inside the body or the use of PET for image-guided procedures, such as biopsy interventions, among others. This work is a proof of concept that aims to improve the user experience with real time PET images. Fixed, incremental, overlapping, sliding and hybrid windows are the different statistical combinations of data blocks used to generate intermediate images in order to follow the path of the activity in the Field Of View (FOV). To evaluate these different combinations, a point source is placed in a dedicated breast PET device and moved along the FOV. These acquisitions are reconstructed according to the different statistical windows, resulting in a smoother transition of positions for the image reconstructions that use the sliding and hybrid window.This study has been realized in the context of the European Union's Seventh Framework Programme for research. L. Moliner was financed with VALi+d program grant.Moliner Martínez, L.; Correcher Salvador, C.; Giménez-Alventosa, V.; Ilisie, V.; Álvarez-Gómez, JM.; Sánchez Góez, S.; Rodríguez-Álvarez, M. (2017). Strategies of statistical windows in PET image reconstruction to improve the user s real time experience. Journal of Physics: Conference Series (Online). 931:1-4. https://doi.org/10.1088/1742-6596/931/1/012025S1493

P-P Total Cross Sections at VHE from Accelerator Data

Comparison of P-P total cross-sections estimations at very high energies - from accelerators and cosmic rays - shows a disagreement amounting to more than 10 %, a discrepancy which is beyond statistical errors. Here we use a phenomenological model based on the Multiple-Diffraction approach to successfully describe data at accelerator energies. The predictions of the model are compared with data On the basis of regression analysis we determine confident error bands, analyzing the sensitivity of our predictions to the employed data for extrapolation. : using data at 546 and 1.8 TeV, our extrapolations for p-p total cross-sections are only compatible with the Akeno cosmic ray data, predicting a slower rise with energy than other cosmic ray results and other extrapolation methods. We discuss our results within the context of constraints in the light of future accelerator and cosmic ray experimental results.Comment: 26 pages aqnd 11 figure

A genome-wide association analysis for body, udder, and leg conformation traits recorded in Murciano-Granadina goats

Morphological traits are of great importance to dairy goat production given their effect on phenotypes of economic interest. However, their underlying genomic architecture has not yet been extensively characterized. Herein, we aimed to identify genomic regions associated with body, udder, and leg conformation traits recorded in 825 Murciano-Granadina goats. We genotyped this resource population using the GoatSNP50 BeadChip (Illumina Inc., San Diego, CA) and performed genome-wide association analyses using the GEMMA software. We found 2 genome-wide significant associations between markers rs268273468 [Capra hircus (CHI) 16:69617700] and rs268249346 (CHI 28:18321523) and medial suspensory ligament. In contrast, we did not detect any genome-wide significant associations for body and leg traits. Moreover, we found 12, 19, and 7 chromosome-wide significant associations for udder, body, and leg traits, respectively. Comparison of our data with previous studies revealed a low level of positional concordance between regions associated with morphological traits. In addition to technical factors, this lack of concordance could be due to a substantial level of genetic heterogeneity among breeds or to the strong polygenic background of morphological traits, which makes it difficult to detect genetic factors that have small phenotypic effects

Strings Near a Rindler Or Black Hole Horizon

Orbifold techniques are used to study bosonic, type II and heterotic strings in Rindler space at integer multiples N of the Rindler temperature, and near a black hole horizon at integer multiples of the Hawking temperature, extending earlier results of Dabholkar. It is argued that a Hagedorn transition occurs nears the horizon for all N>1.Comment: 13 pages, harvmac, (references added

Bone growth during rapamycin therapy in young rats

<p>Abstract</p> <p>Background</p> <p>Rapamycin is an effective immunosuppressant widely used to maintain the renal allograft in pediatric patients. Linear growth may be adversely affected in young children since rapamycin has potent anti-proliferative and anti-angiogenic properties.</p> <p>Methods</p> <p>Weanling three week old rats were given rapamycin at 2.5 mg/kg daily by gavage for 2 or 4 weeks and compared to a Control group given equivalent amount of saline. Morphometric measurements and biochemical determinations for serum calcium, phosphate, iPTH, urea nitrogen, creatinine and insulin-growth factor I (IGF-I) were obtained. Histomorphometric analysis of the growth plate cartilage, in-situ hybridization experiments and immunohistochemical studies for various proteins were performed to evaluate for chondrocyte proliferation, chondrocyte differentiation and chondro/osteoclastic resorption.</p> <p>Results</p> <p>At the end of the 2 weeks, body and tibia length measurements were shorter after rapamycin therapy associated with an enlargement of the hypertrophic zone in the growth plate cartilage. There was a decrease in chondrocyte proliferation assessed by <it>histone-4 </it>and <it>mammalian target of rapamycin </it>(<it>mTOR</it>) expression. A reduction in <it>parathyroid hormone/parathyroid hormone related peptide (PTH/PTHrP) </it>and an increase in <it>Indian hedgehog </it>(<it>Ihh</it>) expression may explain in part, the increase number of hypertrophic chondrocytes. The number of TRAP positive multinucleated chondro/osteoclasts declined in the chondro-osseous junction with a decrease in the <it>receptor activator of nuclear factor kappa β ligand </it>(<it>RANKL</it>) and <it>vascular endothelial growth factor </it>(<it>VEGF</it>) expression. Although body and tibial length remained short after 4 weeks of rapamycin, changes in the expression of chondrocyte proliferation, chondrocyte differentiation and chondro/osteoclastic resorption which were significant after 2 weeks of rapamycin improved at the end of 4 weeks.</p> <p>Conclusion</p> <p>When given to young rats, 2 weeks of rapamycin significantly decreased endochondral bone growth. No catch-up growth was demonstrated at the end of 4 weeks, although markers of chondrocyte proliferation and differentiation improved. Clinical studies need to be done to evaluate these changes in growing children.</p