1,841 research outputs found
Fabrication of strong magnetic micron-sized supraparticles with anisotropic magnetic properties for magnetorheology
Dr Tavacoli is acknowledged for useful discussions. This work
was supported by MICINN PID2019-104883GB-I00 project (Spain), Junta de Andalucı´a P18-FR-2465 project and European
Regional Development Fund (ERDF). J. R. M. acknowledges
FPU14/01576 fellowship. E. C.-G. acknowledges financial support
by CONACYT (Ref. #232347).We propose three different techniques to synthesize anisotropic magnetic supraparticles for their incorporation in the formulation of magnetorheological fluids with novel potential applications. The techniques include microtransfer molding, electrodeposition and microfluidic flow-focusing devices. Although the yield of these methods is not large, with their use, it is possible to synthesize supraparticles with anisotropy in both their magnetic content and shape. The magnetorheological characteristics (yield stress) of the resulting field-induced structures were computed using finite element method simulations and demonstrated to be strongly dependent on the microstructural anisotropy of the supraparticles. In anisotropic particles, the simulated yield stress is always larger than that of the isotropic ones consisting of magnetically homogeneous spherical particles.MICINN PID2019-104883GB-I00 project (Spain)Junta de Andalucía P18-FR-2465 projectEuropean
Regional Development Fund (ERDF)FPU14/01576CONACYT (Ref. #232347
Violation of quark-hadron duality and spectral chiral moments in QCD
We analyze the spectral moments of the V-A two-point correlation function. Using all known short-distance constraints and the most recent experimental data from tau decays, we determine the lowest spectral moments, trying to assess the uncertainties associated with the so-called violations of quark-hadron duality. We have generated a large number of 'acceptable' spectral functions, satisfying all conditions, and have used them to extract the wanted hadronic parameters through a careful statistical analysis. We obtain accurate values for the ChPT couplings L10 and C87, and a realistic determination of the dimension six and eight contributions in the operator product expansion, O6=(-5.4^{+3.6}_{-1.6})*10^-3 GeV^6 and O8=(-8.9^{+12.6}_{-7.4})*10^-3 GeV^8, showing that the duality-violation effects have been usually underestimated in previous literature
Impact of the coronavirus pandemic on maxillofacial trauma:a retrospective study in southern Spain
The coronavirus pandemic has impacted health systems worldwide, with Spain being one of the most affected countries. However, little is known about the extent to which the effects of staying home, social distancing, and quarantine measures have influenced the epidemiology of patients with maxillofacial trauma. The aim of this study was to analyze the impact of the coronavirus pandemic on the incidence, demographic patterns, and characteristics of maxillofacial fractures in the largest hospital in southern Spain. Data from patients who underwent surgery for maxillofacial fractures during the first year of the pandemic between 16 March 2020 and 14 March 2021 (pandemic group) were retrospectively compared with a control group during the equivalent period of the previous year (pre-pandemic group). The incidence was compared by weeks and by lockdown periods of the population. Demographic information, aetioloy, fracture characteristics, treatment performed, and days of preoperative stay were evaluated. Descriptive and bivariate statistics were calculated (p<0.05). During the first year of the pandemic, there was a 35.2% reduction in maxillofacial fractures (n=59) compared to the pre-pandemic year (n=91, p=0.040). A significant drop was detected during the total home lockdown period of the population (p=0.028). In the pandemic group, there was a reduction in fractures due to interpersonal aggressions, an increase in panfacial fractures, a significant increase in other non-facial injuries associated with polytrauma (p=0.037), a higher number of open reduction procedures with internal fixation, and a significantly longer mean preoperative stay (p=0.016). The first pandemic year was associated with a decline in the frequency of maxillofacial trauma and a change in the pattern and characteristics of fractures. Inter-annual epidemiological knowledge of maxillofacial fractures may be useful for more efficient planning of resource allocation and surgical practice strategy during future coronavirus outbreaks and population lockdowns
Effect of organic and inorganic passivation in quantum-dot-sensitized solar cells
The effect of semiconductor passivation on quantum-dot-sensitized solar cells (QDSCs) has been systematically characterized for CdS and CdS/ZnS. We have found that passivation strongly depends on the passivation agent, obtaining an enhancement of the solar cell efficiency for compounds containing amine and thiol groups and, in contrast, a decrease in performance for passivating agents with acid groups. Passivation can induce a change in the position of TiO2 conduction band and also in the recombination rate and nature, reflected in a change in the β parameter. Especially interesting is the finding that β, and consequently the fill factor can be increased with the passivation treatment. Applying this strategy, record cells of 4.65% efficiency for PbS-based QDSCs have been produced.This work was supported by the Institute of Nanotechnologies for Clean Energies (INCE), funded by the Generalitat Valenciana under Project ISIC/2012/008. We thank the following agencies for support of this research: Ministerio de Educacion y Ciencia under project HOPE CSD2007-00007, Generalitat Valenciana (ISIC/2012/008), and Universitat Jaume I project 12I361.01/1. We acknowledge projects CYTED-Nanoenergía, PAPIIT-IN106912 (UNAM-México), and CONACyT-153270 (México) for financial support. M.S.F. acknowledges the fellowship given by CONACyT-México. Funding from National Research Foundation (NRF) Singapore is also kindly acknowledged (CRP Award No. NRF-CRP4-2008-03)
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Silver Nanoparticles Surface-Modified with Carbosilane Dendrons as Carriers of Anticancer siRNA
Gene therapy is a promising approach in cancer treatment; however, current methods have a number of limitations mainly due to the difficulty in delivering therapeutic nucleic acids to their sites of action. The application of non-viral carriers based on nanomaterials aims at protecting genetic material from degradation and enabling its effective intracellular transport. We proposed the use of silver nanoparticles (AgNPs) surface-modified with carbosilane dendrons as carriers of anticancer siRNA (siBcl-xl). Using gel electrophoresis, zeta potential and hydrodynamic diameter measurements, as well as transmission electron microscopy, we characterized AgNP:siRNA complexes and demonstrated the stability of nucleic acid in complexes in the presence of RNase. Hemolytic properties of free silver nanoparticles and complexes, their effect on lymphocyte proliferation and cytotoxic activity on HeLa cells were also examined. Confocal microscopy proved the effective cellular uptake of complexes, indicating the possible use of this type of silver nanoparticles as carriers of genetic material in gene therapy. © 2020 by the authors. Licensee MDPI, Basel, Switzerland
Descripción de un caso de diarrea viral bovina (DVB) en la sabana de Bogotá
Gross and microscopic lesions of bovine viral diarrhea (BVD) in an eight months
old Holstein calf from the Sabana de Bogota are described. The pathological changes
consisted of erosions and ulcers in the digestive tract, and fibrinosous membranes
and necrosis in the esophagus, small and large intestine. The lesions were
similar to those described else where. The diagnosis was confirmed by virus isolation;
the ocurrence of this case is discussed in relation with the high serologic prevalence
of the disease previously determined.Se describen las lesiones macro y microscópicas de un caso natural de diarrea viral bovina (DVB) en una ternera Holstein de 8 meses de edad en la sabana de Bogotá, Colombia. Los cambios patológicos consistieron en erosiones y ulceraciones del tracto digestivo y presencia de membranas fibrinonecróticas en el esófago e intestino delgado y grueso. Los cambios histológicos correspondieron a los descritos en la literatura. El diagnóstico se comprobó mediante el aislamiento del virus. Se discute la presentación de este caso en relación con la alta prevalencia serológioca del virus de DVB observada previamente.Ganado de leche-Ganadería lech
Bone Marrow Clonogenic Myeloid Progenitors from NPM1-Mutated AML Patients Do Not Harbor the NPM1 Mutation: Implication for the Cell-Of-Origin of NPM1+ AML
The cell-of-origin of NPM1- and FLT3-mutated acute myeloid leukemia (AML) is still a matter of debate. Here, we combined in vitro clonogenic assays with targeted sequencing to gain further insights into the cell-of-origin of NPM1 and FLT3-ITD-mutated AML in diagnostic bone marrow (BM) from nine NPM1+/FLT3-ITD (+/-) AMLs. We reasoned that individually plucked colony forming units (CFUs) are clonal and reflect the progeny of a single stem/progenitor cell. NPM1 and FLT3-ITD mutations seen in the diagnostic blasts were found in only 2/95 and 1/57 individually plucked CFUs, suggesting that BM clonogenic myeloid progenitors in NPM1-mutated and NPM1/FLT3-ITD-mutated AML patients do not harbor such molecular lesions. This supports previous studies on NPM1 mutations as secondary mutations in AML, likely acquired in an expanded pool of committed myeloid progenitors, perhaps CD34-, in line with the CD34-/low phenotype of NPM1-mutated AMLs. This study has important implications on the cell-of-origin of NPM1+ AML, and reinforces that therapeutic targeting of either NPM1 or FLT3-ITD mutations might only have a transient clinical benefit in debulking the leukemia, but is unlikely to be curative since will not target the AML-initiating/preleukemic cells. The absence of NPM1 and FLT3-ITD mutations in normal clonogenic myeloid progenitors is in line with their absence in clonal hematopoiesis of indeterminate potential.We thank CERCA/Generalitat de Catalunya and Fundació Josep Carreras-Obra Social la Caixa for their institutional support. Financial support for this work was obtained from the Generalitat de Catalunya (SGR330) to P.M., the Spanish Ministry of Economy and Competitiveness (SAF2016-80481-R to P.M. and SAF2016-76758-R to I.V.), the Fundación Uno entre Cienmil, the Obra Social La Caixa (ID 100010434, under agreement LCF/PR/HR19/52160011), the Josep Carreras Foundation, the Leo Messi Foundation, and the Banco Santander Foundation to P.M.; and the Spanish Association against cancer (AECC-CI-2015) to C.B. E.A. acknowledges support form “Fundación Hay Esperanza”. P.M. is an investigator of the Spanish Cell Therapy cooperative network (TERCEL)
Cognitive impairment induced by delta9-tetrahydrocannabinol occurs through heteromers between cannabinoid CB1 and serotonin 5-HT2A receptors
Delta-9-tetrahydrocannabinol (THC), the main psychoactive compound of marijuana, induces numerous undesirable effects, including memory impairments, anxiety, and dependence. Conversely, THC also has potentially therapeutic effects, including analgesia, muscle relaxation, and neuroprotection. However, the mechanisms that dissociate these responses are still not known. Using mice lacking the serotonin receptor 5-HT2A, we revealed that the analgesic and amnesic effects of THC are independent of each other: while amnesia induced by THC disappears in the mutant mice, THC can still promote analgesia in these animals. In subsequent molecular studies, we showed that in specific brain regions involved in memory formation, the receptors for THC and the 5-HT2A receptors work together by physically interacting with each other. Experimentally interfering with this interaction prevented the memory deficits induced by THC, but not its analgesic properties. Our results highlight a novel mechanism by which the beneficial analgesic properties of THC can be dissociated from its cognitive side effects
A Phase I/II Clinical Trial to evaluate the efficacy of baricitinib to prevent respiratory insufficiency progression in onco-hematological patients affected with COVID19: a structured summary of a study protocol for a randomised controlled trial
Objectives: Baricitinib is supposed to have a double effect on SARS-CoV2 infection. Firstly, it reduces the inflammatory response through the inhibition of the Januse-Kinase signalling transducer and activator of transcription (JAK-STAT) pathway. Moreover, it reduces the receptor mediated viral endocytosis by AP2-associated protein kinase 1 (AAK1) inhibition. We propose the use of baricinitib to prevent the progression of the respiratory insufficiency in SARS-CoV2 pneumonia in onco-haematological patients. In this phase Ib/II study, the primary objective in the safety cohort is to describe the incidence of severe adverse events associated with baricitinib administration. The primary objective of the randomized phase (baricitinib cohort versus standard of care cohort) is to evaluate the number of patients who did not require mechanical oxygen support since start of therapy until day +14 or discharge (whichever it comes first). The secondary objectives of the study (only randomized phase of the study) are represented by the comparison between the two arms of the study in terms of mortality and toxicity at day+30. Moreover, a description of the immunological related changes between the two arms of the study will be reported. Trial design: The trial is a phase I/II study with a safety run-in cohort (phase 1) followed by an open label phase II randomized controlled trial with an experimental arm compared to a standard of care arm
Very Low Mass Stellar and Substellar Companions to Solar-Like Stars From MARVELS V: A Low Eccentricity Brown Dwarf from the Driest Part of the Desert, MARVELS-6b
We describe the discovery of a likely brown dwarf (BD) companion with a
minimum mass of 31.7 +/- 2.0 M_Jup to GSC 03546-01452 from the MARVELS radial
velocity survey, which we designate as MARVELS-6b. For reasonable priors, our
analysis gives a probability of 72% that MARVELS-6b has a mass below the
hydrogen-burning limit of 0.072 M_Sun, and thus it is a high-confidence BD
companion. It has a moderately long orbital period of 47.8929 +0.0063/-0.0062
days with a low eccentricty of 0.1442 +0.0078/-0.0073, and a semi-amplitude of
1644 +12/-13 m/s. Moderate resolution spectroscopy of the host star has
determined the following parameters: T_eff = 5598 +/- 63, log g = 4.44 +/-
0.17, and [Fe/H] = +0.40 +/- 0.09. Based upon these measurements, GSC
03546-01452 has a probable mass and radius of M_star = 1.11 +/- 0.11 M_Sun and
R_star = 1.06 +/- 0.23 R_Sun with an age consistent with less than ~6 Gyr at a
distance of 219 +/- 21 pc from the Sun. Although MARVELS-6b is not observed to
transit, we cannot definitively rule out a transiting configuration based on
our observations. There is a visual companion detected with Lucky Imaging at
7.7 arcsec from the host star, but our analysis shows that it is not bound to
this system. The minimum mass of MARVELS-6b exists at the minimum of the mass
functions for both stars and planets, making this a rare object even compared
to other BDs.Comment: 15 pages, 15 figures, 5 tables. Accepted for publication in The
Astronomical Journa
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