Magnetic-field control of near-field radiative heat transfer and the realization of highly tunable hyperbolic thermal emitters

We present a comprehensive theoretical study of the magnetic field dependence of the near-field radiative heat transfer (NFRHT) between two parallel plates. We show that when the plates are made of doped semiconductors, the near-field thermal radiation can be severely affected by the application of a static magnetic field. We find that irrespective of its direction, the presence of a magnetic field reduces the radiative heat conductance, and dramatic reductions up to 700% can be found with fields of about 6 T at room temperature. We show that this striking behavior is due to the fact that the magnetic field radically changes the nature of the NFRHT. The field not only affects the electromagnetic surface waves (both plasmons and phonon polaritons) that normally dominate the near-field radiation in doped semiconductors, but it also induces hyperbolic modes that progressively dominate the heat transfer as the field increases. In particular, we show that when the field is perpendicular to the plates, the semiconductors become ideal hyperbolic near-field emitters. More importantly, by changing the magnetic field, the system can be continuously tuned from a situation where the surface waves dominate the heat transfer to a situation where hyperbolic modes completely govern the near-field thermal radiation. We show that this high tunability can be achieved with accessible magnetic fields and very common materials like n-doped InSb or Si. Our study paves the way for an active control of NFRHT and it opens the possibility to study unique hyperbolic thermal emitters without the need to resort to complicated metamaterials.Comment: 21 pages, 10 figure

A multilayer service data acquisition and operation system for oceanographic ships and instrumentation networks

A new Data Acquisition and Operation System for Oceanographic ships and Instrumentation Networks has been developed by the Marine Technology Unit of the Spanish Research Vessels for their networked remote acquisition platforms. The new system built over LABVIR project background follows a Service Oriented Architecture to allow expandable access to acquired data in real time and to archived data. Several Data layers are implemented to allow data access from the more common tools and formats used in marine sciences.Peer Reviewe

Metallofluorescent Nanoparticles for Multimodal Applications

Herein, we describe the synthesis and application of cross-linked polystyrene-based dual-function nano- and microparticles containing both fluorescent tags and metals. Despite containing a single dye, these particles exhibit a characteristic dual-band fluorescence emission. Moreover, these particles can be combined with different metal ions to obtain hybrid metallofluorescent particles. We demonstrate that these particles are easily nanofected into living cells, allowing them to be used for effective fingerprinting in multimodal fluorescence-based and mass spectrometry-based flow cytometry experiments. Likewise, the in situ reductions of the metal ions enable other potential uses of the particles as heterogeneous catalysts

The Holocene Cedrus pollen record from Sierra Nevada (S Spain), a proxy for climate change in N Africa

Comprehending the effects of climate variability and disturbance on forested ecosystems is paramount to successfully managing forest environments under future climate scenarios (e.g., global warming, aridi-fication increase). Changes in fossil pollen abundance in sedimentary archives record past vegetation dynamics at regional scales, mainly related to climate changes and, in the last few millennia, to human impact. Pollen records can thus provide long databases with information on how the environment reacted to climate change before the historical record. In this study, we synthesized fossil pollen data from seven sites from the Sierra Nevada in southern Spain to investigate the response of forests in the western Mediterranean area to millennial-scale climate changes and to human impact during the Holocene. In particular, here we focused on Cedrus pollen abundances, which most-likely originated from Northern Africa and were carried to Sierra Nevada by wind. Cedrus pollen has received little attention in the Iberian Peninsula palynological records, for it occurs in low concentrations and has an African source, and thus this article explores the potential to reconstruct its past history and climate. Although Cedrus abundances are generally lower than 1% in the studied pollen samples, a comparison with North African (Moroccan) Cedrus pollen records shows similar trends at long- and short-term time-scales. Therefore, this record could be used as a proxy for changes in this forest species in North Africa. As observed in the Sierra Nevada synthetic record, the increasing trend of Cedrus pollen during the Middle and Late Holocene closely correlates with decreasing summer insolation. This would have produced overall cooler annual temperatures in Northern Africa (Middle Atlas and Rif Mountains) as well as lower summer evaporation, benefiting the growth of this cool-adapted montane tree species while increasing available moisture during the summer, which is critical for this water-demanding species. Millennial-scale variability also characterizes the Sierra Nevada Cedrus synthetic pollen record. Cedrus abundance oscillations co-vary with well-known millennial-scale climatic variability that controlled cedar abundance and altitudinal distribution in montane areas of N Africa. (C) 2020 Elsevier Ltd. All rights reserved.Peer reviewe

1-Ethyl-2,3-dimethylimidazolium paramagnetic ionic liquids with 3D magnetic ordering in its solid state: synthesis, structure and magneto-structural correlations

Financial support from the Spanish Ministerio de Ciencia e Innovaci´on (Projects MAT2011-27573-C04) and Becas Iberoamericas J´ovenes Profesores Investigadores, 2015, Santander Universidades is acknowledged. The authors gratefully acknowledge the MALTA Consolider Ingenio 2010 (Ref. CSD2007-00045). IH acknowledges funding from the EU FP7 (Marie Curie-CIG 303535)

Methylthioadenosine phosphorylase gene expression is impaired in human liver cirrhosis and hepatocarcinoma

Methylthioadenosine phosphorylase (MTAP) is a key enzyme in the methionine and adenine salvage pathways. In mammals, the liver plays a central role in methionine metabolism, and this essential function is lost in the progression from liver cirrhosis to hepatocarcinoma. Deficient MTAP gene expression has been recognized in many transformed cell lines and tissues. In the present work, we have studied the expression of MTAP in human and experimental liver cirrhosis and hepatocarcinoma. We observe that MTAP gene expression is significantly reduced in human hepatocarcinoma tissues and cell lines. Interestingly, MTAP gene expression was also impaired in the liver of CCl4-cirrhotic rats and cirrhotic patients. We provide evidence indicating that epigenetic mechanisms, involving DNA methylation and histone deacetylation, may play a role in the silencing of MTAP gene expression in hepatocarcinoma. Given the recently proposed tumor suppressor activity of MTAP, our observations can be relevant to the elucidation of the molecular mechanisms of multistep hepatocarcinogenesis

New 1-aryl-3-substituted propanol derivatives as antimalarial agents

This paper describes the synthesis and in vitro antimalarial activity against a P. falciparum 3D7 strain of some new 1-aryl-3-substituted propanol derivatives. Twelve of the tested compounds showed an IC50 lower than 1 μM. These compounds were also tested for cytotoxicity in murine J774 macrophages. The most active compounds were evaluated for in vivo activity against P. berghei in a 4-day suppressive test. Compound 12 inhibited more than 50% of parasite growth at a dose of 50 mg/kg/day. In addition, an FBIT test was performed to measure the ability to inhibit ferriprotoporphyrin biocrystallization. This data indicates that 1-aryl-3-substituted propanol derivatives hold promise as a new therapeutic option for the treatment of malaria

Accurate quantification of atherosclerotic plaque volume by 3D vascular ultrasound using the volumetric linear array method.

Direct quantification of atherosclerotic plaque volume by three-dimensional vascular ultrasound (3DVUS) is more reproducible than 2DUS-based three-dimensional (2D/3D) techniques that generate pseudo-3D volumes from summed 2D plaque areas; however, its accuracy has not been reported. We aimed to determine 3DVUS accuracy for plaque volume measurement with special emphasis on small plaques (a hallmark of early atherosclerosis). The in vitro study consisted of nine phantoms of different volumes (small and medium-large) embedded at variable distances from the surface (superficial vs. >5 cm-depth) and comparison of 3DVUS data generated using a novel volumetric-linear array method with the real phantom volumes. The in vivo study was undertaken in a rabbit model of atherosclerosis in which 3DVUS and 2D/3D volume measurements were correlated against gold-standard histological measurements. In the in vitro setting, there was a strong correlation between 3DVUS measures and real phantom volume both for small (3.0-64.5 mm(3) size) and medium-large (91.1-965.5 mm(3) size) phantoms embedded superficially, with intraclass correlation coefficients (ICC) of 0.99 and 0.98, respectively; conversely, when phantoms were placed at >5 cm, the correlation was only moderate (ICC = 0.67). In the in vivo setting there was strong correlation between 3DVUS-measured plaque volumes and the histological gold-standard (ICC = 0.99 [4.02-92.5 mm(3) size]). Conversely, the correlation between 2D/3D values and the histological gold standard (sum of plaque areas) was weaker (ICC = 0.87 [49-520 mm(2) size]), with large dispersion of the differences between measurements in Bland-Altman plots (mean error, 79.2 mm(2)). 3DVUS using the volumetric-linear array method accurately measures plaque volumes, including those of small plaques. Measurements are more accurate for superficial arterial territories than for deep territories.S

Elevated circulating metalloproteinase 7 predicts recurrent cardiovascular events in patients with carotid stenosis: a prospective cohort study

Background: Major adverse cardiovascular events are the main cause of morbidity and mortality over the long term in patients undergoing carotid endarterectomy. There are few reports assessing the prognostic value of markers of inflammation in relation to the risk of cardiovascular disease after carotid endarterectomy. Here, we aimed to determine whether matrix metalloproteinases (MMP-1, MMP-2, MMP-7, MMP-9 and MMP-10), tissue inhibitor of MMPs (TIMP-1) and in vivo inflammation studied by 18F-FDG-PET/CT predict recurrent cardiovascular events in patients with carotid stenosis who underwent endarterectomy. Methods: This prospective cohort study was carried out on 31 consecutive patients with symptomatic (23/31) or asymptomatic (8/31) severe (> 70%) carotid stenosis who were scheduled for carotid endarterectomy between July 2013 and March 2016. In addition, 26 healthy controls were included in the study. Plasma and serum samples were collected 2 days prior to surgery and tested for MMP-1, MMP-2, MMP-7, MMP-9, MMP-10, TIMP-1, high-density lipoprotein, low-density lipoprotein, high-sensitivity C-reactive protein and erythrocyte sedimentation rate. 18F-FDGPET/CT focusing on several territories’ vascular wall metabolism was performed on 29 of the patients because of no presurgical availability in 2 symptomatic patients. Histological and immunohistochemical studies were performed with antibodies targeting MMP-10, MMP-9, TIMP-1 and CD68. Results: The patients with carotid stenosis had significantly more circulating MMP-1, MMP-7 and MMP-10 than the healthy controls. Intraplaque TIMP-1 was correlated with its plasma level (r = 0.42 P = .02) and with 18F-FDG uptake (r = 0.38 P = .05). We did not find any correlation between circulating MMPs and in vivo carotid plaque metabolism assessed by 18F-FDG-PET. After a median follow-up of 1077 days, 4 cerebrovascular, 7 cardiovascular and 11 peripheral vascular events requiring hospitalization were registered. Circulating MMP-7 was capable of predicting events over and above the traditional risk factors (HR = 1.15 P = .006). When the model was associated with the variables of interest, the risk predicted by 18F-FDG-PET was not significant. Conclusions: Circulating MMP-7 may represent a novel marker for recurrent cardiovascular events in patients with moderate to severe carotid stenosis. MMP-7 may reflect the atherosclerotic burden but not plaque inflammation in this specific vascular territory