179 research outputs found
Static quantities of the W boson in the SU_L(3) X U_X(1) model with right-handed neutrinos
The static electromagnetic properties of the boson, and
, are calculated in the SU_L(3)} \times U_X(1) model with
right-handed neutrinos. The new contributions from this model arise from the
gauge and scalar sectors. In the gauge sector there is a new contribution from
a complex neutral gauge boson and a singly-charged gauge boson .
The mass of these gauge bosons, called bileptons, is expected to be in the
range of a few hundreds of GeV according to the current bounds from
experimental data. If the bilepton masses are of the order of 200 GeV, the size
of their contribution is similar to that obtained in other weakly coupled
theories. However the contributions to both and are
negligible for very heavy or degenerate bileptons. As for the scalar sector, an
scenario is examined in which the contribution to the form factors is
identical to that of a two-Higgs-doublet model. It is found that this sector
would not give large corrections to and .Comment: New material included. Final version to apppear in Physical Review
Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results
The chromosphere is a thin layer of the solar atmosphere that bridges the
relatively cool photosphere and the intensely heated transition region and
corona. Compressible and incompressible waves propagating through the
chromosphere can supply significant amounts of energy to the interface region
and corona. In recent years an abundance of high-resolution observations from
state-of-the-art facilities have provided new and exciting ways of
disentangling the characteristics of oscillatory phenomena propagating through
the dynamic chromosphere. Coupled with rapid advancements in
magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly
investigate the role waves play in supplying energy to sustain chromospheric
and coronal heating. Here, we review the recent progress made in
characterising, categorising and interpreting oscillations manifesting in the
solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review
Phospholipid dependent mechanism of smp24, an α-helical antimicrobial peptide from scorpion venom
Determining the mechanism of action of antimicrobial peptides (AMPs) is critical if they are to be developed into the clinical setting. In recent years high resolution techniques such as atomic force microscopy (AFM) have increasingly been utilised to determine AMP mechanism of action on planar lipid bilayers and live bacteria. Here we present the biophysical characterisation of a prototypical AMP from the venom of the North African scorpion Scorpio maurus palmatus termed Smp24. Smp24 is an amphipathic helical peptide containing 24 residues with a charge of + 3 and exhibits both antimicrobial and cytotoxic activity and we aim to elucidate the mechanism of action of this peptide on both membrane systems.
Using AFM, quartz crystal microbalance-dissipation (QCM-D) and liposomal leakage assays the effect of Smp24 on prototypical synthetic prokaryotic (DOPG:DOPC) and eukaryotic (DOPE:DOPC) membranes has been determined. Our data points to a toroidal pore mechanism against the prokaryotic like membrane whilst the formation of hexagonal phase non-lamellar phase structures is seen in eukaryotic like membrane. Also, phase segregation is observed against the eukaryotic membrane and this study provides direct evidence of the same peptide having multiple mechanisms of action depending on the membrane lipid composition
Monocolor chemosensors for Ba2+ tagging experiments
Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.The BOLD experiment is focused on the observation of the neutrinoless double β decay of 136Xe to 136Ba2+ through the detection of the daughter cation. For this purpose, different molecular sensors can be developed. These chemosensors can be classified into monocolor (offon) or bicolor (on-on’), depending on the shifts (Δλ) and changes in the intensity (ΔI) observed in their emission spectra. In this context, different off-on radiometric chemosensors have been synthesized in order to understand their photophysics upon interaction with Ba2+ ions in vacuo and in solution. These sensors incorporate two components: a fluorophore and a metal-binding group. The fluorophores are kept as simple as possible, using structures with well-known photophysical properties. On the other hand, N-aza-crown ether derivatives have been used as metal-binding groups. Finally, the effects of disconnecting the abovementioned elements by splitting of components Ar1 and Ar2
(Figure 1: Description of the off-on chemosensors synthesized in this work), will be discussed.Financial support from the Basque Government (IT-1346-19 and IT-1180-19), the Spanish MICINN (PID2019-104772-GB-I00, PID2019-111281-GB-I00, RED2018-102387-T, and RED2018-102471-T), and by the European Commission (ERC-2020-SyG-951281) is gratefully acknowledged.Peer reviewe
New generation of fluorescent bicolour sensors for barium tagging experiments
Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.One of the most important questions in particle physics and cosmology consists of demonstrating that the neutrino is a Majorana fermion. Observation of the neutrinoless double β decay of 136Xe to generate the daughter cation 136Ba2+ is the most promising practical way to demonstrate this hypothesis. Within this context, our research group has designed and synthesized the first generation of fluorescent bicolour sensors (FBI-G1), whose emission spectra change upon binding to Ba2+ ions by formation of supramolecular complexes in dry media involving solid-gas interphases. In this presentation, the synthesis of a second generation (G2) of bicolour sensors is reported. These sensors have two essential components, a metal-binding group, and a fluorophore. The latest structure is based on a benzo[a]imidazo[2,1,5-cd]indolizine derivative (Figure 1: Description of generation 1 (left) and generation 2 (right) chemosensors). Finally, preliminary research involving the linkage of our sensors to surfaces such as indium tin oxide glass (ITO), will be discussed.Financial support from the Basque Government (IT-1346-19 and IT-1180-19), the Spanish MICINN (PID2019-104772-GB-I00, PID2019-111281-GB-I00, RED2018-102387-T, and RED2018-102471-T), and by the European Commission (ERC-2020-SyG-951281) is gratefully acknowledged.Peer reviewe
Iridium-based sensor for cations
Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.Traditionally, techniques such as inductively coupled plasma mass spectroscopy or gas chromatography have been used for cation detection. However, these methods need long analysis times and sophisticated instrumentation. Simpler and faster methods have been developed these days, such us optical methods (colorimetric and/or fluorescent), which can entail easy visualization, high sensitivity and cheaper instrumentation. Among these, ratiometric (bicolour) fluorescent sensors stand out due to the lower limit of detection. In this area, both organic molecules and metal complexes are being developed as luminescent probes. Indeed, some iridium complexes demonstrated to be selective luminescent sensors for different cations. Different strategies are used to trap or interact with the cation, which permits a rational tuning of the iridium’s emission. In our group, we have been working with iridium complexes for a variety of objectives. In this contribution, an iridium-based sensor for cations will be described including its response to cations in solution and on solid supports.Financial support from the Basque Government (PRE_2020_2_0230, IT-1346-19 and IT-1180-19), the Spanish MICINN (PID2019-104772-GB-I00, PID2019-111281-GB-I00, RED2018-102387-T, and RED2018-102471-T), and by the European Commission (ERC-2020-SyG-951281) is gratefully acknowledged.Peer reviewe
Burden and risk factors for Pseudomonas aeruginosa community-acquired pneumonia:a Multinational Point Prevalence Study of Hospitalised Patients
Pseudornonas aeruginosa is a challenging bacterium to treat due to its intrinsic resistance to the antibiotics used most frequently in patients with community-acquired pneumonia (CAP). Data about the global burden and risk factors associated with P. aeruginosa-CAP are limited. We assessed the multinational burden and specific risk factors associated with P. aeruginosa-CAP.
We enrolled 3193 patients in 54 countries with confirmed diagnosis of CAP who underwent microbiological testing at admission. Prevalence was calculated according to the identification of P. aeruginosa. Logistic regression analysis was used to identify risk factors for antibiotic-susceptible and antibiotic-resistant P. aeruginosa-CAP.
The prevalence of P. aeruginosa and antibiotic-resistant P. aeruginosa-CAP was 4.2% and 2.0%, respectively. The rate of P. aeruginosa CAP in patients with prior infection/colonisation due to P. aeruginosa and at least one of the three independently associated chronic lung diseases (i.e. tracheostomy, bronchiectasis and/or very severe chronic obstructive pulmonary disease) was 67%. In contrast, the rate of P. aeruginosa-CAP was 2% in patients without prior P. aeruginosa infection/colonisation and none of the selected chronic lung diseases. The multinational prevalence of P. aeruginosa-CAP is low.
The risk factors identified in this study may guide healthcare professionals in deciding empirical antibiotic coverage for CAP patients
Team dynamics in emergency surgery teams: results from a first international survey
Background: Emergency surgery represents a unique context. Trauma teams are often multidisciplinary and need to operate under extreme stress and time constraints, sometimes with no awareness of the trauma\u2019s causes or the patient\u2019s personal and clinical information. In this perspective, the dynamics of how trauma teams function is fundamental to ensuring the best performance and outcomes. Methods: An online survey was conducted among the World Society of Emergency Surgery members in early 2021. 402 fully filled questionnaires on the topics of knowledge translation dynamics and tools, non-technical skills, and difficulties in teamwork were collected. Data were analyzed using the software R, and reported following the Checklist for Reporting Results of Internet E-Surveys (CHERRIES). Results: Findings highlight how several surgeons are still unsure about the meaning and potential of knowledge translation and its mechanisms. Tools like training, clinical guidelines, and non-technical skills are recognized and used in clinical practice. Others, like patients\u2019 and stakeholders\u2019 engagement, are hardly implemented, despite their increasing importance in the modern healthcare scenario. Several difficulties in working as a team are described, including the lack of time, communication, training, trust, and ego. Discussion: Scientific societies should take the lead in offering training and support about the abovementioned topics. Dedicated educational initiatives, practical cases and experiences, workshops and symposia may allow mitigating the difficulties highlighted by the survey\u2019s participants, boosting the performance of emergency teams. Additional investigation of the survey results and its characteristics may lead to more further specific suggestions and potential solutions
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