High resolution system for nanoparticles hyperthermia efficiency evaluation

A system to evaluate nanoparticles efficiency in hyperthermia applications is presented. The method allows a direct measurement of the power dissipated by the nanoparticles through the determination of the first harmonic component of the in quadrature magnetic moment induced by the applied field. The magnetic moment is measured by using an induction method. To avoid errors and reduce the noise signal a double in phase demodulation technique is used. To test the system viability we have measured nanowires, nanoparticles and copper samples of different volumes to prove by comparing experimental and modeled result

Vertical Niche Partitioning of Archaea and Bacteria Linked to Shifts in Dissolved Organic Matter Quality and Hydrography in North Atlantic Waters

Understanding the factors that modulate prokaryotic assemblages and their niche partitioning in marine environments is a longstanding challenge in marine microbial ecology. This study analyzes amplicon sequence variant (ASV) diversity and co-occurrence of prokaryotic (Archaea and Bacteria) communities through coastal-oceanic gradients in the NW Iberian upwelling system and adjacent open-ocean (Atlantic Ocean). Biogeographic patterns were investigated in relation with environmental conditions, mainly focusing on the optical signature of the dissolved organic matter (DOM). Alpha- and beta-diversity were horizontally homogeneous [with the only exception of Archaea (∼1700 m depth), attributed to the influence of Mediterranean water, MW], while beta-diversity was significantly vertically stratified. Prokaryotic communities were structured in four clusters (upper subsurface, lower subsurface, intermediate, and deep clusters). Deep (>2000 m) archaeal and bacterial assemblages, and intermediate (500-2000 m) Bacteria (mainly SAR202 and SAR406), were significantly related to humic-like DOM (FDOM-M), while intermediate Archaea were additionally related to biogeochemical attributes of the high-salinity signature of MW. Lower subsurface (100-500 m) Archaea (particularly one ASV belonging to the genus Candidatus Nitrosopelagicus) were mainly related to the imprint of high-salinity MW, while upper subsurface (≤100 m) archaeal assemblages (particularly some ASVs belonging to Marine Group II) were linked to protein-like DOM (aCDOM254). Conversely, both upper and lower subsurface bacterial assemblages were mainly linked to aCDOM254 (particularly ASVs belonging to Rhodobacteraceae, Cyanobacteria, and Flavobacteriaceae) and nitrite concentration (mainly members of Planctomycetes). Most importantly, our analysis unveiled depth-ecotypes, such as the ASVs MarG.II_1 belonging to the archaeal deep cluster (linked to FDOM-M) and MarG.II_2 belonging to the upper subsurface cluster (related to FDOM-T and aCDOM254). This result strongly suggests DOM-mediated vertical niche differentiation, with further implications for ecosystem functioning. Similarly, positive and negative co-occurrence relationships also suggested niche partitioning (e.g., between the closely related ASVs Thaum._Nit._Nit._Nit._1 and _2) and competitive exclusion (e.g., between Thaum._Nit._Nit._Nit._4 and _5), supporting the finding of non-randomly, vertically structured prokaryotic communities. Overall, differences between Archaea and Bacteria and among closely related ASVs were revealed in their preferential relationship with compositional changes in the DOM pool and environmental forcing. Our results provide new insights on the ecological processes shaping prokaryotic assembly and biogeography.Versión del edito

Gas–Solid Heterogeneous Postsynthetic Modification of Imine-Based Covalent Organic Frameworks

This is the peer-reviewed version of the following article: Martín-Illian, J. A., Royuela, S., Ramos, M. M., Segura, J. L., & Zamora, F. (2020). Gas‐Solid Heterogeneous Post‐Synthetic Modification of Imine‐based Covalent Organic Frameworks. Chemistry–A European Journal. 26 (29), 6495-6498, which has been published in final form at https://doi.org/10.1002/chem.202000224. This article may be used for non-commercial purposes in accordance with Wiley-VCH Terms and Conditions for Self-ArchivingThe copper-catalyzed azide–alkyne cycloaddition (CuAAC) click reaction is among the most extensively used strategies for the post-polymerization modification of COFs. This work shows a new procedure for the postsynthetic functionalization of imine-based COFs by using a heterogeneous solid–gas reaction between alkyne-functionalized COFs and azides in the absence of a copper catalyst. This new alternative represents a step forward towards a greener postsynthetic modification of COFs opening a high potential for the development of new applicationsThis work was financially supported by MINECO (MAT2016‐77608‐C3‐1‐P and 2‐P

Synthesis of Ni nanoparticles by dc magnetron sputtering

Magnetic materials have been used with grain sizes down to the nanoscale for longer than any other type of material. The biomedical applications cover from magnetic separation of specific biological entities from their native environment to drug delivery, hyperthermia treatments or MRI contrast enhancement [1]. There are many synthesis methods depending on the final applications of the magnetic nanoparticles [2]. Sputtering methods are less extensively used, maybe due to the low efficiency of the process, however these methods have the advantage of a good control on the composition and size of the particles. Research has focused mainly on Fe [3,4], Co [5] and FeCo alloys [6]. In this work we apply the dc magnetron sputtering technique to the growth of Ni nanoparticles

Changes in activity and community composition shape bacterial responses to size-fraccionated marine DOM

To study the response of bacteria to different size-fractions of naturally occurring dissolved organic matter (DOM), a natural prokaryotic community from North Atlantic mesopelagic waters (1000 m depth) was isolated and grown in (i) 0.1-µm filtered seawater (CONTROL), (ii) the low-molecular-weight (<1 kDa) DOM fraction (L-DOM), and (iii) the recombination of high- (>1 kDa) and low-molecular-weight DOM fractions (H + L-DOM), to test the potential effect of ultrafiltration on breaking the DOM size continuum. Prokaryotic abundance and leucine incorporation were consistently higher in the H + L-DOM niche than in the L-DOM and CONTROL treatments, suggesting a different interaction with each DOM fraction and the disruption of the structural DOM continuum by ultrafiltration, respectively. Rhodobacterales (Alphaproteobacteria) and Flavobacteriales (Bacteroidetes) were particularly enriched in L-DOM and closely related to the colored DOM (CDOM) fraction, indicating the tight link between these groups and changes in DOM aromaticity. Conversely, some other taxa that were rare or undetectable in the original bacterial community were enriched in the H + L-DOM treatment (e.g., Alteromonadales belonging to Gammaproteobacteria), highlighting the role of the rare biosphere as a seed bank of diversity against ecosystem disturbance. The relationship between the fluorescence of protein-like CDOM and community composition of populations in the H + L-DOM treatment suggested their preference for labile DOM. Conversely, the communities growing on the L-DOM niche were coupled to humic-like CDOM, which may indicate their ability to degrade more reworked DOM and/or the generation of refractory substrates (as by-products of the respiration processes). Most importantly, L- and/or H + L-DOM treatments stimulated the growth of unique bacterial amplicon sequence variants (ASVs), suggesting the potential of environmental selection (i.e., changes in DOM composition and availability), particularly in the light of climate change scenarios. Taken together, our results suggest that different size-fractions of DOM induced niche-specialization and differentiation of mesopelagic bacterial communities.Versión del edito

Synthesis of Fe-Au nanoparticles through phase separation using the gas aggregation technique

During the last veers different type of magnetic materials have been obtained either alloys or nanopor-ritlcs with severall metalllics shells. These particle exhibt better magnetic properties, are biocompatible and have optical properties due to their shell noble metal layer, this is possible, to synthesize heterostructured nanoparticles with care/shell structure by using sputtering targets consisting of alloys of different materials. In the case of such materials have different surface energies and atomic sizes, there are diffusion processes which lead to the formation of structured nanoparticles with a shell and core having different composition. In this work we will show the results obtained about Fe-Au nanoparticles grown by I he gas aggregation technique, using magnetron sputering sources. Colloids prepared from sputtered deposits of heterostructed nanoparticles exhibit less aggregation when compared to suspensions obtained from pure magnetic materials. Spectrophotometry measurement show the presence of gold at the surface of the nanoparticles. Magnetic properties of such particle are analyzed by VSM. Compasition end structural analysis are studied by TEM and ÉDA

Stability analysis for the background equations for inflation with dissipation and in a viscous radiation bath

The effects of bulk viscosity are examined for inflationary dynamics in which dissipation and thermalization are present. A complete stability analysis is done for the background inflaton evolution equations, which includes both inflaton dissipation and radiation bulk viscous effects. Three representative approaches of bulk viscous irreversible thermodynamics are analyzed: the Eckart noncausal theory, the linear and causal theory of Israel-Stewart and a more recent nonlinear and causal bulk viscous theory. It is found that the causal theories allow for larger bulk viscosities before encountering an instability in comparison to the noncausal Eckart theory. It is also shown that the causal theories tend to suppress the radiation production due to bulk viscous pressure, because of the presence of relaxation effects implicit in these theories. Bulk viscosity coefficients derived from quantum field theory are applied to warm inflation model building and an analysis is made of the effects to the duration of inflation. The treatment of bulk pressure would also be relevant to the reheating phase after inflation in cold inflation dynamics and during the radiation dominated regime, although very little work in both areas has been done, the methodology developed in this paper could be extended to apply to these other problems.Comment: 27 pages, 14 figures, Published version JCA

Tunable electroactive oligothiophene-naphthalimide semiconductors via end-capped engineering: cumulative effects beyond the linker

Aiming to obtain novel functional semiconducting materials for their use in organic electronics, the combination of strong donor moieties with electron-withdrawing units is one of the most useful strategies to obtain ambipolar semiconductors with tunable properties. Nowadays most of the efforts headed to efficient materials are based on small changes in the alkyl pendant chains or by replacing single atoms. However, a precise design of new functional materials is still challenging. For this reason, in this work we present a new synthetic approach for achieving redox amphoteric organic semiconductors by tuning their opto-electrochemical properties via rational chemical modifications. All these materials present low-lying LUMO levels, lower than −4.00 eV with broad absorption up to 800 nm in the UV-Vis-NIR spectra. In addition, they have been characterized by DFT, absorption and Raman vibrational spectroscopies, while their charge stabilization abilities are studied by means of spectroelectrochemical techniques. The results point out to a quite complex electronic scenario that goes beyond the expected cumulative effects of the independent molecular units constituting the final molecular assembly.Funding for open access charge: Universidad de Málaga / CBU

General dissipation coefficient in low-temperature warm inflation

In generic particle physics models, the inflaton field is coupled to other bosonic and fermionic fields that acquire large masses during inflation and may decay into light degrees of freedom. This leads to dissipative effects that modify the inflationary dynamics and may generate a nearly-thermal radiation bath, such that inflation occurs in a warm rather than supercooled environment. In this work, we perform a numerical computation and obtain expressions for the associated dissipation coefficient in supersymmetric models, focusing on the regime where the radiation temperature is below the heavy mass threshold. The dissipation coefficient receives contributions from the decay of both on-shell and off-shell degrees of freedom, which are dominant for small and large couplings, respectively, taking into account the light field multiplicities. In particular, we find that the contribution from on-shell decays, although Boltzmann-suppressed, can be much larger than that of virtual modes, which is bounded by the validity of a perturbative analysis. This result opens up new possibilities for realizations of warm inflation in supersymmetric field theories.Comment: 25 pages, 13 figures; revised version with new results added; published in JCA

Changes in bacterial activity and community composition in response to water mass mixing

PosterMixing zones and boundaries between different water masses are "hot spots" of marine biodiversity and activity. We aimed to investigate the effects of water mass mixing in the dark-ocean microbial communities by collecting and incubating natural bacterial communities from the Mediterranean Water (MW; at 1000 m depth), the Subpolar Modal Water (SPMW, 500m) and the Labrador Sea Water (LSW, 1800 m), and comparing them with artificially mixed communities. Mixing experiment 1 consisted of incubating at in sity conditions the original LSW and MW communities, plus a mixture of both (MIX1, dilution 1:1), whereas the Mixing experiment 2 included the original prokaryotic communities from SPMW and MW and a mixture of both (MIX2, dilution 1:1). Bacterial abundance and activity was monitored every 24 h over 8 days, while bacterial community composition and DOM characterization were assessed at the beginning (day 0), middle (day 4) and at the end of the experiment (day 8). Live prokaryotic cell abundance was higher in the MIX1 and MIX2 treatments as compared to the original communities. Moreover, MIX bacteria showed slightly higher leucine incorporation rates than MW or LSW. These metabolic responses were accompanied by changes in the optical properties of DOM, suggesting a change in the dynamics of the organic matter. Taken together, our results indicate differences in the bio-reactvity of the organic matter after mixing as compared to the original water masses that could influence the composition and activity of the bacterial community