A microstructural study of superconductive nanocrystalline diamond

A transmission electron microscopy (TEM) study of superconducting nanocrystalline diamond (NCD) continuous layers is reported. The high resolution transmission electron microscopy (HREM) and the diffraction contrast modes of observations are used to reveal the nanograins configuration. Three types of them are observed: first, close to the interface with the Si/SiO2 substrate, 10 to 20 nm-sized diamond 16 seeds resulting from the 5nm size diamond powder deposition before growth that show some regrowth during CVD process, second a diamond overgrown layer, quasi-epitaxially by coalesced columnar NCD grains, and finally, up to the free surface, a thin disordered region composed of nanocrystallites smaller than 6 nm. This last layer was not nominally expected and is attributed to a renucleated-like (RND) diamond layer embedding ultra nanocrystalline grains. Diffraction contrast observations confirm this HREM observed behaviour.6 page

The cyanobacterial ribosomal-associated protein LrtA from Synechocystis sp. PCC 6803 is an oligomeric protein in solution with chameleonic sequence properties

The LrtA protein of Synechocystis sp. PCC 6803 intervenes in cyanobacterial post-stress survival and in stabilizing 70S ribosomal particles. It belongs to the hibernating promoting factor (HPF) family of proteins, involved in protein synthesis. In this work, we studied the conformational preferences and stability of isolated LrtA in solution. At physiological conditions, as shown by hydrodynamic techniques, LrtA was involved in a self-association equilibrium. As indicated by Nuclear Magnetic Resonance (NMR), circular dichroism (CD) and fluorescence, the protein acquired a folded, native-like conformation between pH 6.0 and 9.0. However, that conformation was not very stable, as suggested by thermal and chemical denaturations followed by CD and fluorescence. Theoretical studies of its highly-charged sequence suggest that LrtA had a Janus sequence, with a context-dependent fold. Our modelling and molecular dynamics (MD) simulations indicate that the protein adopted the same fold observed in other members of the HPF family ( - - - - - ) at its N-terminal region (residues 1–100), whereas the C terminus (residues 100–197) appeared disordered and collapsed, supporting the overall percentage of overall secondary structure obtained by CD deconvolution. Then, LrtA has a chameleonic sequence and it is the first member of the HPF family involved in a self-association equilibrium, when isolated in solution.Ministerio de Economía y Competitividad CTQ2015-64445-RMinisterio de Economía y Competitividad BIO2016-78020-RMinisterio de Economía y Competitividad FIS2014-52212-RMinisterio de Economía y Competitividad BIO2016-75634-PFundación Séneca 19353/PI/1

Decidua-derived mesenchymal stem cells as carriers of mesoporous silica nanoparticles. In vitro and in vivo evaluation on mammary tumors

The potential use of human Decidua-derived mesenchymal stem cells (DMSCs) as a platform to carry mesoporous silica nanoparticles in cancer therapy has been investigated. Two types of nanoparticles were evaluated. The nanoparticles showed negligible toxicity to the cells, a fast uptake and a long retention inside them. Nanoparticle location in the cell was studied by colocalization with the lysosomes. Moreover, the in vitro and in vivo migration of DMSCs towards tumors was not modified by the evaluated nanoparticles. Finally, DMSCs transporting doxorubicin-loaded nanoparticles were capable of inducing cancer cell death in vitro

Transcriptional Regulation of zma-MIR528a by Action of Nitrate and Auxin in Maize

In recent years, miR528, a monocot-specific miRNA, has been assigned multifaceted roles during development and stress response in several plant species. However, the transcription regulation and the molecular mechanisms controlling MIR528 expression in maize are still poorly explored. Here we analyzed the zma-MIR528a promoter region and found conserved transcription factor binding sites related to diverse signaling pathways, including the nitrate (TGA1/4) and auxin (AuxRE) response networks. Accumulation of both pre-miR528a and mature miR528 was up-regulated by exogenous nitrate and auxin treatments during imbibition, germination, and maize seedling establishment. Functional promoter analyses demonstrated that TGA1/4 and AuxRE sites are required for transcriptional induction by both stimuli. Overall, our findings of the nitrogen- and auxin-induced zma-MIR528a expression through cis-regulatory elements in its promoter contribute to the knowledge of miR528 regulome

Effect of molecular weight reduction by gamma irradiation on the antioxidant capacity of chitosan from lobster shells

AbstractThis study assessed the effect of molecular weight (MW) reduction by gamma irradiation on the antioxidant capacity of chitosan with potential application in the preservation of foodstuffs. Two batches of chitosan were obtained by heterogeneous chemical N-deacetylation of chitin from common lobster (Panulirus argus). Irradiation of chitosan was performed using a 60Co source and applying doses of 5, 10, 20 and 50 kGy with a dose rate of 10 kGy/h. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy was used to identify main chemical features of chitosan. The average viscosimetric MW was determined by the viscosimetric method while the deacetylation degree by a potentiometric method. Thermogravimetric analysis and differential scanning calorimetry were conducted to evaluate the thermal degradation behavior of the chitosan samples, both under nitrogen flow. The antioxidant activity of chitosan solutions at 1% (w/v) in lactic acid at 1% (v/v) and Tween 80 at 0.1% (v/v) was evaluated through the ABTS assay and scavenging of DPPH radical by chitosan. The increase of irradiation dose with 60Co until 50 kGy decreased significantly the MW of chitosan through the scission of glycosidic bonds without affecting its functional groups, while the DD (72–75 %) did not vary (p > 0.05). The AC of the chitosan solutions increased with the reduction of MW of chitosan by gamma irradiation

High-precision determination of the electric and magnetic form factors of the proton

New precise results of a measurement of the elastic electron-proton scattering cross section performed at the Mainz Microtron MAMI are presented. About 1400 cross sections were measured with negative four-momentum transfers squared up to Q^2=1 (GeV/c)^2 with statistical errors below 0.2%. The electric and magnetic form factors of the proton were extracted by fits of a large variety of form factor models directly to the cross sections. The form factors show some features at the scale of the pion cloud. The charge and magnetic radii are determined to be r_E=0.879(5)(stat.)(4)(syst.)(2)(model)(4)(group) fm and r_M=0.777(13)(stat.)(9)(syst.)(5)(model)(2)(group) fm.Comment: 5 pages, 2 figures, published in Phys. Rev. Lett. v3: added references, updated text, color figure

Reply to Comment on "High-Precision Determination of the Electric and Magnetic Form Factors of the Proton"

In arXiv:1108.3058v1 [nucl-ex], Arrington criticizes the Coulomb corrections we applied in the analysis of high precision form factor data (see Phys.Rev.Lett.105:242001, 2010, arXiv:1007.5076v3 [nucl-ex]). We show, by comparing different calculations cited in the Comment, that the criticism of the Comment neglects the large uncertainty of "more modern" TPE corrections. This uncertainty has also been seen in recent polarized measurements. We rerun our analysis using one of these calculations. The results show that the Comment exaggerates the quantitative effect at small Q^2.Comment: 1 page, 2 figure, To appear as a Reply Comment in Physical Review Letter

MAP4K3 mediates amino acid-dependent regulation of autophagy via phosphorylation of TFEB

Autophagy is the major cellular pathway by which macromolecules are degraded, and amino acid depletion powerfully activates autophagy. MAP4K3, or germinal-center kinase-like kinase, is required for robust cell growth in response to amino acids, but the basis for MAP4K3 regulation of cellular metabolic disposition remains unknown. Here we identify MAP4K3 as an amino acid-dependent regulator of autophagy through its phosphorylation of transcription factor EB (TFEB), a transcriptional activator of autophagy, and through amino acid starvation-dependent lysosomal localization of MAP4K3. We document that MAP4K3 physically interacts with TFEB and MAP4K3 inhibition is sufficient for TFEB nuclear localization, target gene transactivation, and autophagy, even when mTORC1 is activated. Moreover, MAP4K3 serine 3 phosphorylation of TFEB is required for TFEB interaction with mTORC1-Rag GTPase-Ragulator complex and TFEB cytosolic sequestration. Our results uncover a role for MAP4K3 in the control of autophagy and reveal MAP4K3 as a central node in nutrient-sensing regulation

The electric and magnetic form factors of the proton

The paper describes a precise measurement of electron scattering off the proton at momentum transfers of $0.003 \lesssim Q^2 \lesssim 1$\ GeV$^2$. The average point-to-point error of the cross sections in this experiment is $\sim$ 0.37%. These data are used for a coherent new analysis together with all world data of unpolarized and polarized electron scattering from the very smallest to the highest momentum transfers so far measured. The extracted electric and magnetic form factors provide new insight into their exact shape, deviating from the classical dipole form, and of structure on top of this gross shape. The data reaching very low $Q^2$ values are used for a new determination of the electric and magnetic radii. An empirical determination of the Two-Photon-Exchange (TPE) correction is presented. The implications of this correction on the radii and the question of a directly visible signal of the pion cloud are addressed.Comment: 38 pages, 20 figures. Updated data files. PRC versio

Unexplored outflows in nearby low luminosity AGNs: the case of NGC 1052

Outflows play a central role in galaxy evolution shaping the properties of galaxies. Understanding outflows and their effects in low luminosity AGNs, such as LINERs, is essential (e.g. they are a numerous AGN population in the local Universe). We obtained VLT/MUSE and GTC/MEGARA optical IFS-data for NGC1052, the prototypical LINER. The stars are distributed in a dynamically hot disc, with a centrally peaked velocity dispersion map and large observed velocity amplitudes. The ionised gas, probed by the primary component is detected up to $\sim$30arcsec ($\sim$3.3 kpc) mostly in the polar direction with blue and red velocities ($\mid$V$\mid$$<$250 km/s). The velocity dispersion map shows a notable enhancement ($\sigma$$>$90 km/s) crossing the galaxy along the major axis of rotation in the central 10arcsec. The secondary component has a bipolar morphology, velocity dispersion larger than 150 km/s and velocities up to 660 km/s. A third component is detected but not spatially resolved. The maps of the NaD absorption indicate optically thick neutral gas with a velocity field consistent with a slow rotating disc ($\Delta$V = 77$\pm$12 km/s) but the velocity dispersion map is off-centred without any counterpart in the flux map. We found evidence of an ionised gas outflow with mass of 1.6$\pm$0.6 $\times$ 10$^{5}$ Msun, and mass rate of 0.4$\pm$0.2 Msun/yr. The outflow is propagating in a cocoon of gas with enhanced turbulence and might be triggering the onset of kpc-scale buoyant bubbles (polar emission). Taking into account the energy and kinetic power of the outflow (1.3$\pm$0.9 $\times$ 10$^{53}$ erg and 8.8$\pm$3.5 $\times$ 10$^{40}$ erg/s, respectively) as well as its alignment with both the jet and the cocoon, and that the gas is collisionally ionised, we consider that the outflow is jet-powered, although some contribution from the AGN is possible.Comment: A&A accepted 04/04/2022, 31 pages, 12 figures and 3 appendixe