Investigating the transformations of polyoxoanions using mass spectrometry and molecular dynamics

The reactions of [γ-SiW10O36]8– represent one of the most important synthetic gateways into a vast array of polyoxotungstate chemistry. Herein, we set about exploring the transformation of the lacunary polyoxoanion [β2-SiW11O39]8– into [γ-SiW10O36]8– using high-resolution electrospray mass spectrometry, density functional theory, and molecular dynamics. We show that the reaction proceeds through an unexpected {SiW9} precursor capable of undertaking a direct β → γ isomerization via a rotational transformation. The remarkably low-energy transition state of this transformation could be identified through theoretical calculations. Moreover, we explore the significant role of the countercations for the first time in such studies. This combination of experimental and the theoretical studies can now be used to understand the complex chemical transformations of oxoanions, leading to the design of reactivity by structural control

Extreme Horizontal Wind Perturbations in the Mesosphere and Lower Thermosphere Over South America Associated With the 2022 Hunga Eruption

On 15 January 2022, the Hunga volcano produced a massive explosion that generated perturbations in the entire atmosphere. Nonetheless, signatures in the mesosphere and lower thermosphere (MLT) have been challenging to identify. We report MLT horizontal wind perturbations using three multistatic specular meteor radars on the west side of South America (spanning more than 3,000 km). The most notorious signal is an exceptional solitary wave with a large vertical wavelength observed around 18 UT at all three sites, with an amplitude of ∼50 m/s mainly in the westward direction. Using a customized analysis, the wave is characterized as traveling at ∼200 m/s, with a period of ∼2 hr and a horizontal wavelength of ∼1,440 km in the longitudinal direction, away from the source. The perturbation is consistent with an L1 Lamb wave mode. The signal's timing coincides with the arrival time of the tsunami triggered by the eruption

Pronóstico de la insuficiencia cardíaca aguda basado en datos clínicos de congestión

Acute heart failure; Congestion; Emergency departments; MortalityInsuficiència cardíaca aguda; Congestió; Serveis d'urgències; MortalitatInsuficiencia cardiaca aguda; Congestión; Servicios de urgencias; MortalidadBackground and objectives: This work aims to assess whether symptoms/signs of congestion in patients with acute heart failure (AHF) evaluated in hospital emergency departments (HED) allows for predicting short-term progress. Patients and methods: The study group comprised consecutive patients diagnosed with AHF in 45 HED from EAHFE Registry. We collected clinical variables of systemic congestion (edema in the lower extremities, jugular vein distention, hepatomegaly) and pulmonary congestion (dyspnea on exertion, paroxysmal nocturnal dyspnea, orthopnea, and pulmonary crackles) and analysed their individual and group association with all-cause 30-day of mortality crudely and adjusted for differences between groups. Results: We analysed 18,120 patients (median = 83 years, interquartile range [IQR] = 76-88; women = 55.7%). Of them, 44.6% had > 3 congestive symptoms/signs. Individually, the 30-day adjusted risk of death increased 14% for jugular vein distention (hazard ratio [HR] = 1.14, 95% confidence interval [95%CI] = 1.01-1.28) and 96% for dyspnea on exertion (HR = 1.96, 95% CI = 1.55-2.49). Assessed jointly, the risk progressively increased with the number of symptoms/signs present; compared to patients without symptoms/signs of congestion, the risk increased by 109%, 123 %, and 156% in patients with 1-2, 3-5, and 6-7 symptoms/signs, respectively. These associations did not show interaction with the final disposition of the patient after their emergency care (discharge/hospitalization) with the exception of edema in the lower extremities, which had a better prognosis in discharged patients (HR = 0.66, 95% CI = 0.49-0.89) than hospitalised patients (HR = 1.01, 95% CI = 0.65-1.57; interaction p < 0.001). Conclusion: The presence of a greater number of congestive symptoms/signs was associated with greater all-cause 30-day mortality. Individually, jugular vein distention and dyspnea on exertion were associated with higher short-term mortality.Antecedentes y objetivos: : Evaluar si los síntomas/signos de congestión en pacientes con insuficiencia cardíaca aguda (ICA) atendidos en los servicios de urgencias hospitalarios (SUH) permiten predecir la evolución a corto plazo. Pacientes y métodos: Pacientes consecutivos diagnosticados de ICA en 45 SUH del Registro EAHFE. Recogimos variables clínicas de congestión sistémica (edemas en miembros inferiores, ingurgitación yugular, hepatomegalia) y pulmonar (disnea de esfuerzo, disnea paroxística nocturna, ortopnea y crepitantes pulmonares) analizando su asociación con la mortalidad por cualquier causa a 30 días, de forma cruda y ajustada por diferencias entre grupos. Resultados: Analizamos 18.120 pacientes (mediana = 83 anos, ˜ rango intercuartil [RIC] = 76---88; mujeres = 55,7%). El 44,6% presentaba >3 síntomas/signos congestivos. Individualmente, el riesgo ajustado de muerte a 30 días se incrementó un 14% para la existencia de ingurgitación yugular (hazard ratio [HR] = 1,14, intervalo de confianza al 95% [IC95%] = 1,01−1,28) y un 96% para la disnea de esfuerzo (HR = 1,96, IC95% = 1,55−2,49). Valorados conjuntamente, el riesgo se incrementó progresivamente con el número de síntomas/signos presentes; así, respecto a los pacientes sin síntomas/signos de congestión, el riesgo incrementó un 109%, 123% y 156% en pacientes con 1---2, 3---5 y 6---7 síntomas/signos respectivamente. Estas asociaciones no mostraron interacción con la disposición final del paciente tras su atención en Urgencias (alta/hospitalización), con excepción de edemas en extremidades inferiores, que tuvieron mejor pronóstico en pacientes dados de alta (HR = 0,66, IC95% = 0,49−0,89) que en los hospitalizados (HR = 1,01, IC95% = 0,65−1,57; p interacción <0,001). Conclusión: La presencia de mayor número de síntomas/signos congestivos se asoció a una mayor mortalidad de cualquier causa a los 30 días. Individualmente, la ingurgitación yugular y la disnea de esfuerzo se asocian a mayor mortalidad a corto plazo

Epithelial-to-mesenchymal stem cell transition in a human organ: Lessons from Lichen Planopilaris

YesEpithelial-to-mesenchymal transition (EMT) is critical for embryonic development and wound healing, and occurs in fibrotic disease and carcinoma. Here, we show that EMT also occurs within the bulge, the epithelial stem cell (eSC) niche of human scalp hair follicles, during the inflammatory permanent alopecia, lichen planopilaris. We show that a molecular EMT signature can be experimentally induced in healthy human eSCs in situ by antagonizing E-cadherin, combined with transforming growth factor-β1, epidermal growth factor, and IFN-γ administration, which to our knowledge has not been reported previously. Moreover, induction of EMT within primary human eSCs can be prevented and even partially reversed ex vivo by peroxisome proliferator−activated receptor-γ agonists, likely through suppression of the transforming growth factor-β signaling pathway. Furthermore, we show that peroxisome proliferator−activated receptor-γ agonists also attenuates the EMT signature even in lesional lichen planopilaris hair follicles ex vivo. We introduce lichen planopilaris as a model disease for pathological EMT in human adult eSCs, report a preclinical assay for therapeutically manipulating eSC EMT within a healthy human (mini-)organ, and show that peroxisome proliferator−activated receptor-γ agonists are promising agents for suppressing and partially reversing EMT in human hair follicles eSCs ex vivo, including in lichen planopilaris

Acoustic far-field hypersonic surface wave detection with single plasmonic nanoantennas

The optical properties of small metallic particles allow us to bridge the gap between the myriad of subdiffraction local phenomena and macroscopic optical elements. The optomechanical coupling between mechanical vibrations of Au nanoparticles and their optical response due to collective electronic oscillations leads to the emission and the detection of surface acoustic waves (SAWs) by single metallic nanoantennas. We take two Au nanoparticles, one acting as a source and the other as a receptor of SAWs and, even though these antennas are separated by distances orders of magnitude larger than the characteristic subnanometric displacements of vibrations, we probe the frequency content, wave speed, and amplitude decay of SAWs originating from the damping of coherent mechanical modes of the source. Two-color pump-probe experiments and numerical methods reveal the characteristic Rayleigh wave behavior of emitted SAWs, and show that the SAW-induced optical modulation of the receptor antenna allows us to accurately probe the frequency of the source, even when the eigenmodes of source and receptor are detuned

Stability, Electronic Structure and Vibrational Modes of Ti_8C_12 Dimer

We present our density functional results of the geometry, electronic structure and dissociation energy of Ti_8C_12 dimer. We show that as opposed to the currently held view that Ti_8C_12 are highly stable monodispersed clusters, the neutral Ti_8C_12 clusters form covalent bonds and form stable dimers. We determine that the Ti atoms bond weakly (0.9 eV/bond) to organic ligands such as ammonia. Alternatively the Met-Car dimer has a cohesive energy of 4.84 eV or approximately 1.2 eV per bond. While Met-Car dimers are stable, formation of these dimers may be quenched in an environment that contains a significant population of organic ligands. The ionization and dissociation energies of the dimer are of same order which prevents the observation of the dimer in the ion mass spectroscopy. The analysis of the vibrational frequencies show the lowest-energy structure to be dynamically stable. We also present infrared absorption and Raman scattering spectra of the Ti_8C_12 dimer.Comment: 5 pages, 3 figures (Better quality figures available on request). Physical Review B (Rapid Communication) (2002, in press

Production of Embryonic and Fetal-Like Red Blood Cells from Human Induced Pluripotent Stem Cells

We have previously shown that human embryonic stem cells can be differentiated into embryonic and fetal type of red blood cells that sequentially express three types of hemoglobins recapitulating early human erythropoiesis. We report here that we have produced iPS from three somatic cell types: adult skin fibroblasts as well as embryonic and fetal mesenchymal stem cells. We show that regardless of the age of the donor cells, the iPS produced are fully reprogrammed into a pluripotent state that is undistinguishable from that of hESCs by low and high-throughput expression and detailed analysis of globin expression patterns by HPLC. This suggests that reprogramming with the four original Yamanaka pluripotency factors leads to complete erasure of all functionally important epigenetic marks associated with erythroid differentiation regardless of the age or the tissue type of the donor cells, at least as detected in these assays. The ability to produce large number of erythroid cells with embryonic and fetal-like characteristics is likely to have many translational applications