3,058 research outputs found

    Switching of Magnetic Moments of Nanoparticles by Surface Acoustic Waves

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    We report evidence of the magnetization reversal in nanoparticles by surface acoustic waves (SAWs). The experimental system consists of isolated magnetite nanoparticles dispersed on a piezoelectric substrate. Magnetic relaxation from a saturated state becomes significantly enhanced in the presence of the SAW at a constant temperature of the substrate. The dependence of the relaxation on SAW power and frequency has been investigated. The effect is explained by the effective ac magnetic field generated by the SAW in the nanoparticles.Comment: Accepted in Europhysics Letter

    Influence of external driving on decays in the geometry of the LiCN isomerization

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    The framework of transition state theory relies on the determination of a geometric structure identifying reactivity. It replaces the laborious exercise of following many trajectories for a long time to provide chemical reaction rates and pathways. In this paper, recent advances in constructing this geometry even in time-dependent systems are applied to the LiCN ⇌\rightleftharpoons LiNC isomerization reaction, driven by an external field. We obtain decay rates of the reactant population close to the transition state by exploiting local properties of the dynamics of trajectories in and close to it. We find that the external driving has a large influence on these decay rates when compared to the non-driven isomerization reaction. This, in turn, provides renewed evidence for the possibility of controlling chemical reactions, like this one, through external time-dependent fields.Comment: Main article has 11 pages, 6 figures. Supplemental material has 4 pages, 1 figur

    Marine forests of the Mediterranean-Atlantic Cystoseira tamariscifolia complex show a southern Iberian genetic hotspot and no reproductive isolation in parapatry

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    Climate-driven range-shifts create evolutionary opportunities for allopatric divergence and subsequent contact, leading to genetic structuration and hybrid zones. We investigate how these processes influenced the evolution of a complex of three closely related Cystoseira spp., which are a key component of the Mediterranean-Atlantic seaweed forests that are undergoing population declines. The C. tamariscifolia complex, composed of C. tamariscifolia s.s., C. amentacea and C. mediterranea, have indistinct boundaries and natural hybridization is suspected. Our aims are to (1) infer the genetic structure and diversity of these species throughout their distribution ranges using microsatellite markers to identify ancient versus recent geographical populations, contact zones and reproductive barriers, and (2) hindcast past distributions using niche models to investigate the influence of past range shifts on genetic divergence at multiple spatial scales. Results supported a single, morphologically plastic species the genetic structure of which was incongruent with a priori species assignments. The low diversity and low singularity in northern European populations suggest recent colonization after the LGM. The southern Iberian genetic hotspot most likely results from the role of this area as a climatic refugium or a secondary contact zone between differentiated populations or both. We hypothesize that life-history traits (selfing, low dispersal) and prior colonization effects, rather than reproductive barriers, might explain the observed genetic discontinuities.Pew Charitable Trusts (USA); MARINERA, Spain [CTM2008-04183-E/MAR]; FCT (Portugal) [FCT-BIODIVERSA/004/2015, CCMAR/Multi/04326/2013, SFRH/BPD/107878/2015, SFRH/BPD/85040/2012]; FPU fellowship of the Spanish Ministry of Education; European Community ASSEMBLE visiting grant [00399/2012]; University of Cadi

    Mean first-passage times for solvated LiCN isomerization at intermediate to high temperatures

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    The following article appeared in The Journal of Chemical Physics 156 (2022): 034103 and may be found at https://aip.scitation.org/doi/full/10.1063/5.0065090The behavior of a particle in a solvent has been framed using stochastic dynamics since the early theory of Kramers. A particle in a chemical reaction reacts slower in a diluted solvent because of the lack of energy transfer via collisions. The flux-over-population reaction rate constant rises with increasing density before falling again for very dense solvents. This Kramers turnover is observed in this paper at intermediate and high temperatures in the backward reaction of the LiNC ⇌ LiCN isomerization via Langevin dynamics and mean first-passage times (MFPTs). It is in good agreement with the Pollak-Grabert-Hänggi (PGH) reaction rates at lower temperatures. Furthermore, we find a square root behavior of the reaction rate at high temperatures and have made direct comparisons of the methods in the intermediate- and high-temperature regimes, all suggesting increased ranges in accuracy of both the PGH and MFPT approache

    Efficacy of psychological interventions on psychological outcomes in coronary artery disease: systematic review and meta-analysis.

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    The benefits of cognitive-behavioral treatment (CBT) and positive psychology therapy (PPT) in patients with cardiovascular disease are still not well defined. We assessed the efficacy of CBT and PPT on psychological outcomes in coronary artery disease (CAD) patients. Randomized controlled trials evaluating CBT or PPT in CAD patients published until May 2018 were systematically analyzed. Primary outcomes were depression, stress, anxiety, anger, happiness, and vital satisfaction. Random effects meta-analyses using the inverse variance method were performed. Effects were expressed as standardized mean difference (SMD) or mean differences (MD) with their 95% confidence intervals (CIs); risk of bias was assessed with the Cochrane tool. Nineteen trials were included (n = 1956); sixteen evaluated CBT (n = 1732), and three PPT (n = 224). Compared with control groups, depressive symptoms (13 trials; SMD -0.80; 95% CI -1.33 to -0.26), and anxiety (11 trials; SMD -1.26; 95% CI -2.11 to -0.41) improved after the PI, and depression (6 trials; SMD -2.08; 95% CI -3.22 to -0.94), anxiety (5 trials; SMD -1.33; 95% CI -2.38 to -0.29), and stress (3 trials; SMD -3.72; 95% CI -5.91 to -1.52) improved at the end of follow-up. Vital satisfaction was significantly increased at follow-up (MD 1.30, 0.27, 2.33). Non-significant effects on secondary outcomes were found. Subgroup analyses were consistent with overall analyses. CBT and PPT improve several psychological outcomes in CAD patients. Depression and anxiety improved immediately after the intervention while stress and vital satisfaction improve in the mid-term. Future research should assess the individual role of CBT and PPT in CAD populations.Dr. Bueno receives research funding from the Instituto de Salud Carlos III, Spain (PIE16/00021 &PI17/01799), Astra-Zeneca, BMS, Janssen and Novartis; has received consulting fees from Astra-Zeneca, Bayer, BMS-Pfizer, Novartis; and speaking fees or support for attending scientific meetings from Astra-Zeneca, Bayer, BMS-Pfizer, Novartis, and MEDSCAPE-theheart.org. Dr. Jurado receives research funding from the Ministerio de Ciencia, Innovación y Universidades, Spain (PSI2015-68851-P). Dr. Magán, Dr. Jurado, Dr. Redondo and Dr. Bueno have received funding from Universidad Camilo José Cela, Madrid – Spain (2015-18). Dr. Hernandez receives funding from the Agency Health Care Research and Quality (AHRQ) (HHSA290201500012I). The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovación and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505).S

    A Comparative Study of Age-Related Hearing Loss in Wild Type and Insulin-Like Growth Factor I Deficient Mice

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    Insulin-like growth factor-I (IGF-I) belongs to the family of insulin-related peptides that fulfils a key role during the late development of the nervous system. Human IGF1 mutations cause profound deafness, poor growth and mental retardation. Accordingly, Igf1−/− null mice are dwarfs that have low survival rates, cochlear alterations and severe sensorineural deafness. Presbycusis (age-related hearing loss) is a common disorder associated with aging that causes social and cognitive problems. Aging is also associated with a decrease in circulating IGF-I levels and this reduction has been related to cognitive and brain alterations, although there is no information as yet regarding the relationship between presbycusis and IGF-I biodisponibility. Here we present a longitudinal study of wild type Igf1+/+ and null Igf1−/− mice from 2 to 12 months of age comparing the temporal progression of several parameters: hearing, brain morphology, cochlear cytoarchitecture, insulin-related factors and IGF gene expression and IGF-I serum levels. Complementary invasive and non-invasive techniques were used, including auditory brainstem-evoked response (ABR) recordings and in vivo MRI brain imaging. Igf1−/− null mice presented profound deafness at all the ages studied, without any obvious worsening of hearing parameters with aging. Igf1+/+ wild type mice suffered significant age-related hearing loss, their auditory thresholds and peak I latencies augmenting as they aged, in parallel with a decrease in the circulating levels of IGF-I. Accordingly, there was an age-related spiral ganglion degeneration in wild type mice that was not evident in the Igf1 null mice. However, the Igf1−/− null mice in turn developed a prematurely aged stria vascularis reminiscent of the diabetic strial phenotype. Our data indicate that IGF-I is required for the correct development and maintenance of hearing, supporting the idea that IGF-I-based therapies could contribute to prevent or ameliorate age-related hearing loss

    A Mathematical Model to Optimize the Neoadjuvant Chemotherapy Treatment Sequence for Triple-Negative Locally Advanced Breast Cancer

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    Background: Triple-negative locally advanced breast cancer is an aggressive tumor type. Currently, the standard sequence treatment is applied, administering anthracyclines first and then a taxane plus platinum. Clinical studies for all possible treatment combinations are not practical or affordable, but mathematical modeling of the active mitotic cell population is possible. Our study aims to show the regions with the tumor’s most substantial cellular population variation by utilizing all possible values of the parameters () that define the annihilatory drug capacity according to the proposed treatment. Method: A piecewise linear mathematical model was used to analyze the cell population growth by applying four treatments: standard sequences of 21 days (SS21) and 14 days (SS14), administering anthracyclines first, followed by a taxane plus platinum, and inverted sequences of 21 days (IS21) and 14 days (IS14), administering a taxane plus platinum first then anthracyclines. Results: The simulation showed a higher effect of IS14 over SS14 when the rate of drug resistance was larger in the cell population during DNA synthesis (G1 and S) compared to cells in mitosis (G2 and M). However, if the proportion of resistant cells in both populations was equivalent, then treatments did not differ. Conclusions: When resistance is considerable, IS14 is more efficient than SS14, reducing the tumor population to a minimum

    Retinol binding Protein-4 circulating levels were higher in nonalcoholic fatty liver disease vs. histologically normal liver from morbidly obese women.

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    We aimed to analyze the retinol binding protein-4 (RBP4) messenger RNA (mRNA) expression profiles in adipose tissues and liver of morbidly obese (MO) women with or without nonalcoholic fatty liver disease (NAFLD), and to study the relationships with other pro- and anti-inflammatory adipokines in vivo and in vitro. We performed a cross-sectional analysis of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and liver samples from four lean and 45 MO women with or without NAFLD by enzyme-linked immunosorbent assay and real-time reverse transcription-PCR. We also studied RBP4 expression in HepG2 hepatocytes under various inflammatory stimuli. Circulating RBP4 levels were higher in MO women, and specifically, in MO subjects with NAFLD compared with normal liver controls (lean and MO). RBP4 liver expression was higher in nonalcoholic steatohepatitis (NASH)-moderate/severe than in NASHmild. Overall RBP4 gene expression was higher in liver than in adipose tissues. Among them, the higher expression corresponded to SAT. VAT expression was lower in the MO cohort. In HepG2, RBP4 mRNA expression was reduced by tumor necrosis factor (TNF)-α and increased by adiponectin treatment. In conclusion, the results obtained in MO women with NAFLD, brings up the use of RBP4 and other adipokines as a panel of noninvasive molecular biomarkers when NAFLD is suspected. Further studies are needed with other obesity groups.Fil: Terra, Ximena. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Auguet, Teresa. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; España. Hospital Universitari Joan XXIII. Servei Medicina Interna,; EspañaFil: Broch, Montserrat. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Sabench, Fátima. Hospital Sant Joan de Reus. Servei de Cirurgia,; EspañaFil: Hernandez, Mercè. Hospital Sant Joan de Reus. Servei de Cirurgia,; EspañaFil: Pastor, Rosa M.. Hospital Universitari Joan XXIII. Laboratori de Bioquímica; EspañaFil: Quesada, Isabel María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Lunna, Ana. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Aguilar, Carmen. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; EspañaFil: Del Castillo, Daniel. Hospital Sant Joan de Reus. Servei de Cirurgia, ; EspañaFil: Richard, Cristobal. Universitat Rovira i Virgil. Departament de Medicina i Cirurgia; España. Hospital Universitari Joan XXIII. Servei Medicina Interna,; Españ
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