Potential vorticity of the south polar vortex of Venus

©2016. American Geophysical UnionVenus' atmosphere shows highly variable warm vortices over both of the planet's poles. The nature of the mechanism behind their formation and properties is still unknown. Potential vorticity is a conserved quantity when advective processes dominate over friction and diabatic heating and is a quantity frequently used to model balanced flows. As a step toward understanding the vortices' dynamics, we present maps of Ertel's potential vorticity (EPV) at Venus' south polar region. We analyze three configurations of the south polar vortex at the upper cloud level (P ~ 240 mbar; z ~ 58 km), based on our previous analyses of cloud motions and thermal structure from data acquired by the Visual and InfraRed Thermal Imaging Spectrometer instrument on board Venus Express. Additionally, we tentatively estimate EPV at the lower cloud level (P ~ 2200 mbar; z ~ 43 km), based on our previous wind measurements and on static stability data from Pioneer Venus and the Venus International Reference Atmosphere (VIRA) model. Values of EPV are on the order of 10−6 and 10−8 K m2 kg−1 s−1 at the upper and lower cloud levels, respectively, being 3 times larger than the estimated errors. The morphology observed in EPV maps is mainly determined by the structures of the vertical component of the relative vorticity. This is in contrast to the vortex's morphology observed in 3.8 or 5 µm images which are related to the thermal structure of the atmosphere at the cloud top. Some of the EPV maps point to a weak ringed structure in the upper cloud, while a more homogenous EPV field is found in the lower cloud

Laser-Assisted Production of Carbon-Encapsulated Pt-Co Alloy Nanoparticles for Preferential Oxidation of Carbon Monoxide

C-encapsulated highly pure PtxCoy alloy nanoparticles have been synthesized by an innovative one-step in-situ laser pyrolysis. The obtained X-ray diffraction pattern and transmission electron microscopy images correspond to PtxCoy alloy nanoparticles with average diameters of 2.4 nm and well-established crystalline structure. The synthesized PtxCoy/C catalyst containing 1.5 wt% of PtxCoy nanoparticles can achieve complete CO conversion in the temperature range 125–175°C working at weight hourly space velocities (WHSV) of 30 L h−1g−1. This study shows the first example of bimetallic nanoalloys synthesized by laser pyrolysis and paves the way for a wide variety of potential applications and metal combinations

In Cellulo Bioorthogonal Catalysis by Encapsulated AuPd Nanoalloys. Overcoming Intracellular Deactivation

Bioorthogonal metallocatalysis has opened up a xenobiotic route to perform nonenzymatic catalytic transformations in living settings. Despite their promising features, most metals are deactivated inside cells by a myriad of reactive biomolecules, including biogenic thiols, thereby limiting the catalytic functioning of these abiotic reagents. Here we report the development of cytocompatible alloyed AuPd nanoparticles with the capacity to elicit bioorthogonal depropargylations with high efficiency in biological media. We also show that the intracellular catalytic performance of these nanoalloys is significantly enhanced by protecting them following two different encapsulation methods. Encapsulation in mesoporous silica nanorods resulted in augmented catalyst reactivity, whereas the use of a biodegradable PLGA matrix increased nanoalloy delivery across the cell membrane. The functional potential of encapsulated AuPd was demonstrated by releasing the potent chemotherapy drug paclitaxel inside cancer cells. Nanoalloy encapsulation provides a novel methodology to develop nanoreactors capable of mediating new-to-life reactions in cell

Application of Copper-Based NPs for Cancer Therapy in 3D Microfluidic-Based Cell Culture Model

En este trabajo se ha utilizado un modelo de cultivo celular 3D basado en microfluídica para crecer esferoides tumorales de glioblastoma y realizar un estudio del efecto de NPs basadas en cobre como posible terapia antitumoral. Se han obtenido resultados satisfactorios sobre el crecimiento, la viabilidad y la capacidad metastásica

Planetary population synthesis

In stellar astrophysics, the technique of population synthesis has been successfully used for several decades. For planets, it is in contrast still a young method which only became important in recent years because of the rapid increase of the number of known extrasolar planets, and the associated growth of statistical observational constraints. With planetary population synthesis, the theory of planet formation and evolution can be put to the test against these constraints. In this review of planetary population synthesis, we first briefly list key observational constraints. Then, the work flow in the method and its two main components are presented, namely global end-to-end models that predict planetary system properties directly from protoplanetary disk properties and probability distributions for these initial conditions. An overview of various population synthesis models in the literature is given. The sub-models for the physical processes considered in global models are described: the evolution of the protoplanetary disk, the planets' accretion of solids and gas, orbital migration, and N-body interactions among concurrently growing protoplanets. Next, typical population synthesis results are illustrated in the form of new syntheses obtained with the latest generation of the Bern model. Planetary formation tracks, the distribution of planets in the mass-distance and radius-distance plane, the planetary mass function, and the distributions of planetary radii, semimajor axes, and luminosities are shown, linked to underlying physical processes, and compared with their observational counterparts. We finish by highlighting the most important predictions made by population synthesis models and discuss the lessons learned from these predictions - both those later observationally confirmed and those rejected.Comment: 47 pages, 12 figures. Invited review accepted for publication in the 'Handbook of Exoplanets', planet formation section, section editor: Ralph Pudritz, Springer reference works, Juan Antonio Belmonte and Hans Deeg, Ed

Biodiesel production from used cooking oil using a novel surface functionalised TiO2 nano-catalyst

A novel, efficient and recyclable mesoporous TiO2/PrSO3H solid acid nano-catalyst was synthesised by the post-synthetic grafting of propyl sulfonic acid groups onto a mixed phase of a TiO2 support. The synthesised nano-catalyst was characterised using FTIR, SEM, TEM, XPS, N2 adsorption–desorption isotherms, XRD, DSC, TGA, and CHNS analysis. The percentage of loading for propyl sulfonic acid on the TiO2 support was calculated using CHNS analysis and TGA. The catalytic performance of TiO2/PrSO3H on the production of the fatty acid methyl esters (FAME) via simultaneous esterification and transesterification reactions from used cooking oil (UCO) has been studied. The effects of different process parameters showed that 98.3% of FAME can be obtained after 9 hrs of reaction time with 1:15 molar ratio of oil to methanol, 60 °C reaction temperature and 4.5 wt% catalyst loading. It was also found that the one-pot post-surface functionalisation strategy with hydrophilic functional groups (-SO3H) enhanced the acid strengths of the nano-catalyst providing more acid sites for the reactants, and improving the accessibility of methanol to the triglycerides (TG)/free fatty acids (FFAs) by increasing the pore volumes/sizes of the nano-catalyst. The solid acid nano-catalyst was re-used in four consecutive runs without significant loss of catalytic efficiency. Finally, the synthesised biodiesel fuel satisfied ASTM and EN standards

Involvement of yeast HSP90 isoforms in response to stress and cell death induced by acetic acid

Acetic acid-induced apoptosis in yeast is accompanied by an impairment of the general protein synthesis machinery, yet paradoxically also by the up-regulation of the two isoforms of the heat shock protein 90 (HSP90) chaperone family, Hsc82p and Hsp82p. Herein, we show that impairment of cap-dependent translation initiation induced by acetic acid is caused by the phosphorylation and inactivation of eIF2 alpha by Gcn2p kinase. A microarray analysis of polysome-associated mRNAs engaged in translation in acetic acid challenged cells further revealed that HSP90 mRNAs are over-represented in this polysome fraction suggesting preferential translation of HSP90 upon acetic acid treatment. The relevance of HSP90 isoform translation during programmed cell death (PCD) was unveiled using genetic and pharmacological abrogation of HSP90, which suggests opposing roles for HSP90 isoforms in cell survival and death. Hsc82p appears to promote survival and its deletion leads to necrotic cell death, while Hsp82p is a pro-death molecule involved in acetic acid-induced apoptosis. Therefore, HSP90 isoforms have distinct roles in the control of cell fate during PCD and their selective translation regulates cellular response to acetic acid stress.This work was supported by Fundacao para a Ciencia e Tecnologia and COMPETE/QREN/EU (PTDC/BIA-MIC/114116/2009), and by the Canadian Institute for Health Research (MOP 89737 to MH). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

The Mars Environmental Dynamics Analyzer, MEDA. A Suite of Environmental Sensors for the Mars 2020 Mission

86 pags., 49 figs., 24 tabs.NASA’s Mars 2020 (M2020) rover mission includes a suite of sensors to monitor current environmental conditions near the surface of Mars and to constrain bulk aerosol properties from changes in atmospheric radiation at the surface. The Mars Environmental Dynamics Analyzer (MEDA) consists of a set of meteorological sensors including wind sensor, a barometer, a relative humidity sensor, a set of 5 thermocouples to measure atmospheric temperature at ∼1.5 m and ∼0.5 m above the surface, a set of thermopiles to characterize the thermal IR brightness temperatures of the surface and the lower atmosphere. MEDA adds a radiation and dust sensor to monitor the optical atmospheric properties that can be used to infer bulk aerosol physical properties such as particle size distribution, non-sphericity, and concentration. The MEDA package and its scientific purpose are described in this document as well as how it responded to the calibration tests and how it helps prepare for the human exploration of Mars. A comparison is also presented to previous environmental monitoring payloads landed on Mars on the Viking, Pathfinder, Phoenix, MSL, and InSight spacecraft.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects No. ESP2014-54256-C4-1-R (also -2-R, -3-R and -4-R) and AYA2015-65041-P; Ministry of Science, Innovation and Universities, projects No. ESP2016-79612-C3-1-R (also -2-R and -3-R), ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also -C32 and -C33) and RTI2018-099825-B-C31; Instituto Nacional de Técnica Aeroespacial; Ministry of Science and Innovation’s Centre for the Development of Industrial Technology; Grupos Gobierno Vasco IT1366-19; and European Research Council Consolidator Grant no 818602. The US co-authors performed their work under sponsorship from NASA’s Mars 2020 project, from the Game Changing Development program within the Space Technology Mission Directorate and from the Human Exploration and Operations Directorate

Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency–Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research