3,204 research outputs found
Evaluation of synthesis time in the growth of vertical-aligned MWCNTs by spray pyrolysis
Multi-Wall Carbon Nanotubes (MWCNTs) were analyzed on crystalline silicon substrates (type P) under optimal temperature conditions, using different synthesis times (2, 3, 4, 5, 10, 20, 30, 60, 120, and 180 min) in order to examine the effect on the structural quality and length of the CNTs produced by ultrasonic spray pyrolysis, using pure toluene and ferrocene as precursor solutions under argon flow. Structural, optical, and morphological differences of the MWCNTs grown were analyzed. Raman spectroscopy evidenced the MWCNTs' high quality, noted by the ID/IG (from 0.41 to 0.68) and I2D/IG intensity ratios around 0.75. Morphological differences of the MWCNTs grow evaluated by Field Emission Scanning Electron Microscopy (FE-SEM); the micrographs examined the thickness of CNTs' layers. High-Resolution Transmission Electron Microscopy (HRTEM) technique was used to determine the diameters of CNTs, which were found from 15 to 140 nm. X-Ray Diffraction (XRD) showed two characteristic peaks around 26° and 44°, which corroborated that the MWCNTs were well-graphitized. The influence of the time in these CNTs demonstrated that the final length of these nanotubes could easily reach micrometers. The alienation was better as time increased, and the graphitization extent is good in most cases compared to other more expensive synthesis methods.We thank Technician Adrian Gómez Herrero, Technician Cristina Moral Gil and Hugo Solera for the TEM, SEM and Raman characterization, respectively. This work has been supported by the thematic network "Nanostructure advanced materials and applications in Mexico" between Spain and Mexico sponsoring this international collaboration. This work has been financially supported by Comunidad de Madrid, Spain (S2018/NMT-4411) and Ministry of Economia, Industría y Competividad (PID2019-106631GB-C43)
Cancer progression by breast tumors with Pit-1-overexpression is blocked by inhibition of metalloproteinase (MMP)-13
Chemical abundances and ages of the bulge stars in APOGEE high-velocity peaks
A cold high-velocity (HV, 200 km/s) peak was first reported in several
Galactic bulge fields based on the APOGEE commissioning observations. Both the
existence and the nature of the high-velocity peak are still under debate. Here
we revisit this feature with the latest APOGEE DR13 data. We find that most of
the low latitude bulge fields display a skewed Gaussian distribution with a HV
shoulder. However, only 3 out of 53 fields show distinct high-velocity peaks
around 200 km/s. The velocity distribution can be well described by
Gauss-Hermite polynomials, except the three fields showing clear HV peaks. We
find that the correlation between the skewness parameter () and the mean
velocity (), instead of a distinctive HV peak, is a strong indicator
of the bar. It was recently suggested that the HV peak is composed of
preferentially young stars. We choose three fields showing clear HV peaks to
test this hypothesis using the metallicity, [/M] and [C/N] as age
proxies. We find that both young and old stars show HV features. The similarity
between the chemical abundances of stars in the HV peaks and the main component
indicates that they are not systematically different in terms of chemical
abundance or age. In contrast, there are clear differences in chemical space
between stars in the Sagittarius dwarf and the bulge stars. The strong HV peaks
off-plane are still to be explained properly, and could be different in nature.Comment: 13 pages, 10 figures, published in ApJ. Updated to match the final
ApJ published version. Minor revisions to the text and Figure
Combining GAL4 GFP enhancer trap with split luciferase to measure spatiotemporal promoter activity in Arabidopsis.
In multicellular organisms different types of tissues have distinct gene expression profiles associated with specific function or structure of the cell. Quantification of gene expression in whole organs or whole organisms can give misleading information about levels or dynamics of expression in specific cell types. Tissue- or cell-specific analysis of gene expression has potential to enhance our understanding of gene regulation and interactions of cell signalling networks. The Arabidopsis circadian oscillator is a gene network which orchestrates rhythmic expression across the day/night cycle. There is heterogeneity between cell and tissue types of the composition and behaviour of the oscillator. In order to better understand the spatial and temporal patterns of gene expression, flexible tools are required. By combining a Gateway®-compatible split luciferase construct with a GAL4 GFP enhancer trap system, we describe a tissue-specific split luciferase assay for non-invasive detection of spatiotemporal gene expression in Arabidopsis. We demonstrate the utility of this enhancer trap-compatible split luciferase assay (ETSLA) system to investigate tissue-specific dynamics of circadian gene expression. We confirm spatial heterogeneity of circadian gene expression in Arabidopsis leaves and describe the resources available to investigate any gene of interest
Lung Cytokines and Systemic Inflammation in Patients with COPD
Rationale: Chronic obstructive pulmonary disease (COPD) is characterized by lung and systemic inflammation. The role of cytokines in local and systemic inflammation in COPD is not well understood. This study aimed to compare plasma and bronchoalveolar lavage (BAL) fluid cytokine levels in COPD and non-COPD subjects with the intent of better understand their potential roles in driving local and systemic inflammation.
Methods: This cross-sectional study analyzed data from 65 subjects: 31 with COPD confirmed by spirometry and 34 non-COPD controls. All subjects underwent spirometry, plasma sample collection, and bronchoscopy/BAL. Levels of 21 inflammatory cytokines were measured in the plasma (systemic inflammation) and BAL (lung inflammation) using a multiplex assay.
Results:COPD subjects were overall older (median age 59 vs 36; p =
Conclusion: Elevated levels of cytokines were identified in the plasma of COPD subjects when compared to controls, supporting the role of these mediators as one of the mechanisms of systemic inflammation in COPD. In contrast, lung cytokines were not elevated suggesting that inflammation in the setting of COPD may not originate and/or perpetuate in the lungs, or that the BAL fluid is not an optimal source of information when evaluating inflammation in COPD. Although the role of these cytokines remains uncertain, anti-cytokine therapy might modulate inflammation in COPD and perhaps improve outcomes
Occupation-Related Differences in the Prevalence of Metabolic Syndrome
OBJECTIVE—To investigate the prevalence of metabolic syndrome in the Spanish working population and determine how the prevalence varies according to occupation and sex
Benchmarking the power of amateur observatories for TTV exoplanets detection
This document is the Accepted Manuscript version of the following article: Roman v. Baluev, et al, ‘Benchmarking the power of amateur observatories for TTV exoplanets detection’, Monthly Notices of the Royal Astronomical Society, Vol. 450(3): 3101-3113, first published online 9 May 2015. The version of record is available at doi: https://doi.org/10.1093/mnras/stv788 © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.We perform an analysis of ~80000 photometric measurements for the following 10 stars hosting transiting planets: WASP-2, -4, -5, -52, Kelt-1, CoRoT-2, XO-2, TrES-1, HD 189733, GJ 436. Our analysis includes mainly transit lightcurves from the Exoplanet Transit Database, public photometry from the literature, and some proprietary photometry privately supplied by other authors. Half of these lightcurves were obtained by amateurs. From this photometry we derive 306 transit timing measurements, as well as improved planetary transit parameters. Additionally, for 6 of these 10 stars we present a set of radial velocity measurements obtained from the spectra stored in the HARPS, HARPS-N, and SOPHIE archives using the HARPS-TERRA pipeline. Our analysis of these TTV and RV data did not reveal significant hints of additional orbiting bodies in almost all of the cases. In the WASP-4 case, we found hints of marginally significant TTV signals having amplitude 10-20 sec, although their parameters are model-dependent and uncertain, while radial velocities did not reveal statistically significant Doppler signals.Peer reviewe
The AAA plus chaperone VCP disaggregates Tau fibrils and generates aggregate seeds in a cellular system
Amyloid-like aggregates of the microtubule-associated protein Tau are associated with several neurodegenerative disorders including Alzheimer's disease. The existence of cellular machinery for the removal of such aggregates has remained unclear, as specialized disaggregase chaperones are thought to be absent inmammalian cells. Here we show in cell culture and in neurons that the hexameric ATPase valosin-containing protein (VCP) is recruited to ubiquitylated Tau fibrils, resulting in their efficient disaggregation. Aggregate clearance depends on the functional cooperation of VCP with heat shock 70 kDa protein (Hsp70) and the ubiquitin-proteasome machinery. While inhibition of VCP activity stabilizes large Tau aggregates, disaggregation by VCP generates seeding-active Tau species as byproduct. These findings identify VCP as a core component of the machinery for the removal of neurodegenerative disease aggregates and suggest that its activity can be associated with enhanced aggregate spreading in tauopathies
Survival analysis and sentinel lymph node status in thin cutaneous melanoma: A multicenter observational study
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