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1.
Angew Chem Int Ed Engl ; : e202417392, 2024 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-39364908

RESUMEN

The Reverse Water Gas-Shift reaction (CO2 + H2=CO + H2O) allows to balance syn-gas under industrial conditions. Nickel has been suggested as a potential catalyst but the temperature required is too high, more than 800ºC, limiting practical implementation but when lowering the temperature methanation occurs. Simulations via Density Functional Theory on well-defined surfaces have systematically failed to reproduce these experimental results. But under reaction conditions Ni surfaces are not static and DFT models coupled to microkinetics show that at high CO coverages drive the generation of Ni adatoms that are the active sites for methanation. At higher temperatures, the adatom population decreases, and the selectivity towards CO increases. Thus, the mechanism behind the selectivity switch is driven by the dynamics induced by reaction intermediates. Our work contributes to the inclusion of dynamic aspects of materials under reaction conditions in the understanding of complex catalytic behaviour.

2.
Medicina (Kaunas) ; 60(9)2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39336503

RESUMEN

Background and Objectives: The aim was to compare the activity of the masseter muscles in children with different types of breathing. Materials and Methods: A cross-sectional study was conducted including patients aged 6-12 years with mixed dentition, who came for oral care at the Master's Degree in Pediatric Dentistry program at the Complutense University of Madrid (UCM), according to inclusion and exclusion criteria. The sample was divided into three groups: nasal breathers without dental alterations (control group), oral breathers with dental malocclusion, and oral breathers with previous orthodontic treatment. An electromyography was performed, and statistic methods were conducted with a 95% confidence to contrast hypothesis. Results: A total of 122 children were analyzed and distributed into three groups. The electrical muscle activity of masseters was significantly different between the study groups (p < 0.001 for all comparisons). Pairwise comparisons revealed a significantly higher electrical muscle activity in the control group (nasal breathers) during chewing compared to both groups of oral breathers (p < 0.001 for both comparisons). Orthodontic treatment decreased electrical muscle activity during isometric contraction in oral breathers compared to nasal breathers (p < 0.001), but did not significantly affect electrical muscle activity during chewing. Higher decompensation values were obtained in oral breathers without previous orthodontic treatment compared the other study groups (p < 0.001 for both comparisons), although electrical muscle activity values were similar in both groups of oral breathers (p > 0.05 for both comparisons). Conclusions: Differences in electrical muscle activity between nasal and oral breathers can be confirmed. Oral breathers with and without orthodontic treatment showed lower electrical muscle activity of masseters during chewing than nasal breathers, while at isometric contraction, only oral breathers with previous orthodontic treatment showed lower electrical activity. Higher decompensation values were found in oral breathers without previous orthodontic treatment, in comparison to the control group and oral breathers with previous orthodontic treatment.


Asunto(s)
Electromiografía , Músculos Masticadores , Humanos , Niño , Masculino , Femenino , Estudios Transversales , Músculos Masticadores/fisiología , Músculos Masticadores/fisiopatología , Respiración , Músculo Masetero/fisiología , Músculo Masetero/fisiopatología , Masticación/fisiología , Respiración por la Boca/fisiopatología , Respiración por la Boca/complicaciones , Maloclusión/fisiopatología , Maloclusión/complicaciones , Maloclusión/terapia
3.
Nat Med ; 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39215150

RESUMEN

Clonal hematopoiesis, a condition in which acquired somatic mutations in hematopoietic stem cells lead to the outgrowth of a mutant hematopoietic clone, is associated with a higher risk of hematological cancer and a growing list of nonhematological disorders, most notably atherosclerosis and associated cardiovascular disease. However, whether accelerated atherosclerosis is a cause or a consequence of clonal hematopoiesis remains a matter of debate. Some studies support a direct contribution of certain clonal hematopoiesis-related mutations to atherosclerosis via exacerbation of inflammatory responses, whereas others suggest that clonal hematopoiesis is a symptom rather than a cause of atherosclerosis, as atherosclerosis or related traits may accelerate the expansion of mutant hematopoietic clones. Here we combine high-sensitivity DNA sequencing in blood and noninvasive vascular imaging to investigate the interplay between clonal hematopoiesis and atherosclerosis in a longitudinal cohort of healthy middle-aged individuals. We found that the presence of a clonal hematopoiesis-related mutation confers an increased risk of developing de novo femoral atherosclerosis over a 6-year period, whereas neither the presence nor the extent of atherosclerosis affects mutant cell expansion during this timeframe. These findings indicate that clonal hematopoiesis unidirectionally promotes atherosclerosis, which should help translate the growing understanding of this condition into strategies for the prevention of atherosclerotic cardiovascular disease in individuals exhibiting clonal hematopoiesis.

4.
J Invest Dermatol ; 2024 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-39127929

RESUMEN

Skin in vitro models offer much promise for research, testing drugs, cosmetics, and medical devices, reducing animal testing and extensive clinical trials. There are several in vitro approaches to mimicking human skin behavior, ranging from simple cell monolayer to complex organotypic and bioengineered 3-dimensional models. Some have been approved for preclinical studies in cosmetics, pharmaceuticals, and chemicals. However, development of physiologically reliable in vitro human skin models remains in its infancy. This review reports on advances in in vitro complex skin models to study skin homeostasis, aging, and skin disease.

5.
Children (Basel) ; 11(8)2024 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-39201921

RESUMEN

BACKGROUND: SmartAction-VR uses virtual reality to simulate daily life tasks and assess cognitive performance based on the multi-errand paradigm. This study explored whether this new task could provide insights into the executive functioning of children and adolescents with ADHD in their everyday activities. METHODS: A cross-sectional study was conducted between November 2021 and December 2022. It consisted of one session and was divided into two parts (cognitive tests; and SmartAction-VR). The sample comprised 76 children and adolescents with a median age (IQR) of 13 (11-14) years and an age range of 9-17 years. Of these participants, 60.50% (n = 46) were males. Out of this sample, 40 participants were in the ADHD group and 36 were in the neurotypical group. The following instruments were used: Waisman Activities of Daily Living Scale, Assessment of Sensory Processing and Executive Functioning, Pediatric Simulator Disease Questionnaire, Digit span subtest, Stroop test, NEPSY-II Subtest of Auditory Attention and Cognitive Flexibility, Trail Making Test, Zoo Map Test, and SmartAction-VR. RESULTS: The ADHD group demonstrated lower accuracy (U = 406, p = 0.010), higher values for total errors (U = 292, p = 0.001), more commissions (U = 417, p = 0.003), new actions (U = 470, p = 0.014), and forgetting actions (U = 406, p = 0.010), as well as fewer perseverations compared to the neurotypical group (U = 540.5, p = 0.029). Additionally, participants who forgot more actions were found to have lower independence in daily life (r = -0.281, p = 0.024). CONCLUSIONS: The correlations between the results of SmartAction-VR and activities of daily living, as well as cognitive tests, suggest that this new task could be useful for evaluating executive functioning in daily life.

6.
Cell Rep ; 43(7): 114390, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-38900636

RESUMEN

Timed feeding drives adipose browning, although the integrative mechanisms for the same remain unclear. Here, we show that twice-a-night (TAN) feeding generates biphasic oscillations of circulating insulin and leptin, representing their entrainment by timed feeding. Insulin and leptin surges lead to marked cellular, functional, and metabolic remodeling of subcutaneous white adipose tissue (sWAT), resulting in increased energy expenditure. Single-cell RNA-sequencing (scRNA-seq) analyses and flow cytometry demonstrate a role for insulin and leptin surges in innate lymphoid type 2 (ILC2) cell recruitment and sWAT browning, since sWAT depot denervation or loss of leptin or insulin receptor signaling or ILC2 recruitment each dampens TAN feeding-induced sWAT remodeling and energy expenditure. Consistently, recreating insulin and leptin oscillations via once-a-day timed co-injections is sufficient to favorably remodel innervated sWAT. Innervation is necessary for sWAT remodeling, since denervation of sWAT, but not brown adipose tissue (BAT), blocks TAN-induced sWAT remodeling and resolution of inflammation. In sum, reorganization of nutrient-sensitive pathways remodels sWAT and drives the metabolic benefits of timed feeding.


Asunto(s)
Tejido Adiposo Pardo , Insulina , Leptina , Animales , Leptina/metabolismo , Insulina/metabolismo , Tejido Adiposo Pardo/metabolismo , Ratones , Ratones Endogámicos C57BL , Metabolismo Energético , Tejido Adiposo Blanco/metabolismo , Masculino , Conducta Alimentaria/fisiología
7.
Science ; 384(6702): 1373-1380, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38900890

RESUMEN

The oxygen evolution reaction is the bottleneck to energy-efficient water-based electrolysis for the production of hydrogen and other solar fuels. In proton exchange membrane water electrolysis (PEMWE), precious metals have generally been necessary for the stable catalysis of this reaction. In this work, we report that delamination of cobalt tungstate enables high activity and durability through the stabilization of oxide and water-hydroxide networks of the lattice defects in acid. The resulting catalysts achieve lower overpotentials, a current density of 1.8 amperes per square centimeter at 2 volts, and stable operation up to 1 ampere per square centimeter in a PEMWE system at industrial conditions (80°C) at 1.77 volts; a threefold improvement in activity; and stable operation at 1 ampere per square centimeter over the course of 600 hours.

8.
Nat Commun ; 15(1): 3101, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38600146

RESUMEN

Metal promotion could unlock high performance in zinc-zirconium catalysts, ZnZrOx, for CO2 hydrogenation to methanol. Still, with most efforts devoted to costly palladium, the optimal metal choice and necessary atomic-level architecture remain unclear. Herein, we investigate the promotion of ZnZrOx catalysts with small amounts (0.5 mol%) of diverse hydrogenation metals (Re, Co, Au, Ni, Rh, Ag, Ir, Ru, Pt, Pd, and Cu) prepared via a standardized flame spray pyrolysis approach. Cu emerges as the most effective promoter, doubling methanol productivity. Operando X-ray absorption, infrared, and electron paramagnetic resonance spectroscopic analyses and density functional theory simulations reveal that Cu0 species form Zn-rich low-nuclearity CuZn clusters on the ZrO2 surface during reaction, which correlates with the generation of oxygen vacancies in their vicinity. Mechanistic studies demonstrate that this catalytic ensemble promotes the rapid hydrogenation of intermediate formate into methanol while effectively suppressing CO production, showcasing the potential of low-nuclearity metal ensembles in CO2-based methanol synthesis.

9.
Nat Commun ; 15(1): 3397, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38649389

RESUMEN

Electrochemical CO2 reduction reaction in aqueous electrolytes is a promising route to produce added-value chemicals and decrease carbon emissions. However, even in Gas-Diffusion Electrode devices, low aqueous CO2 solubility limits catalysis rate and selectivity. Here, we demonstrate that when assembled over a heterogeneous electrocatalyst, a film of nitrile-modified Metal-Organic Framework (MOF) acts as a remarkable CO2-solvation layer that increases its local concentration by ~27-fold compared to bulk electrolyte, reaching 0.82 M. When mounted on a Bi catalyst in a Gas Diffusion Electrode, the MOF drastically improves CO2-to-HCOOH conversion, reaching above 90% selectivity and partial HCOOH currents of 166 mA/cm2 (at -0.9 V vs RHE). The MOF also facilitates catalysis through stabilization of reaction intermediates, as identified by operando infrared spectroscopy and Density Functional Theory. Hence, the presented strategy provides new molecular means to enhance heterogeneous electrochemical CO2 reduction reaction, leading it closer to the requirements for practical implementation.

10.
Dent J (Basel) ; 12(4)2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38667996

RESUMEN

Dental development defects (DDDs) are quantitative and/or qualitative alterations produced during odontogenesis that affect both primary and permanent dentition. The etiology remains unknown, being associated with prenatal, perinatal, and postnatal factors. The aims were to identify the possible etiological factors, as well as the prevalence of DDDs in the primary and permanent dentition in a pediatric population. Two hundred twenty-one children between 2 and 15 years of age, patients of the master's degree in Pediatric Dentistry of the Complutense University of Madrid, were reviewed. DDDs were observed in 60 children. Next, a cross-sectional, case-control study was carried out (60 children in the control group and 60 children in the case group). The parents or guardians completed a questionnaire aimed at identifying associated etiological factors. The prevalence of DDDs in patients attending our master's program in both dentitions was 27.15%. Otitis, tonsillitis, high fevers, and medication intake stood out as the most relevant postnatal factors among cases and controls. The permanent maxillary right permanent central incisor and the primary mandibular right second molar were the most affected; there were no differences in relation to gender. One out of three children who presented DDDs in the primary dentition also presented DDDs in the permanent dentition. Prenatal and postnatal etiological factors showed a significant relationship with DDD alterations, considered risk factors for DDDs in both dentitions.

11.
Nat Commun ; 15(1): 2349, 2024 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-38514609

RESUMEN

Safe and effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are crucial to fight against the coronavirus disease 2019 pandemic. Most vaccines are based on a mutated version of the Spike glycoprotein [K986P/V987P (S-2P)] with improved stability, yield and immunogenicity. However, S-2P is still produced at low levels. Here, we describe the V987H mutation that increases by two-fold the production of the recombinant Spike and the exposure of the receptor binding domain (RBD). S-V987H immunogenicity is similar to S-2P in mice and golden Syrian hamsters (GSH), and superior to a monomeric RBD. S-V987H immunization confer full protection against severe disease in K18-hACE2 mice and GSH upon SARS-CoV-2 challenge (D614G or B.1.351 variants). Furthermore, S-V987H immunized K18-hACE2 mice show a faster tissue viral clearance than RBD- or S-2P-vaccinated animals challenged with D614G, B.1.351 or Omicron BQ1.1 variants. Thus, S-V987H protein might be considered for future SARS-CoV-2 vaccines development.


Asunto(s)
COVID-19 , Melfalán , SARS-CoV-2 , gammaglobulinas , Cricetinae , Animales , Humanos , Ratones , Mesocricetus , Vacunas contra la COVID-19 , COVID-19/prevención & control , Glicoproteína de la Espiga del Coronavirus/genética , Inmunización , Glicoproteínas , Anticuerpos Neutralizantes , Anticuerpos Antivirales
12.
BMC Oral Health ; 24(1): 229, 2024 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-38350956

RESUMEN

OBJECTIVE: The main objective of this study was to estimate the prevalence of molar incisor hypomineralisation (MIH), an alteration of tooth enamel with an estimated worldwide prevalence rate of 14%, among children using primary care services in the Community of Madrid, Spain. MATERIALS AND METHODS: This was a descriptive, cross-sectional and multicentre study. After calibrating all researchers and following the diagnostic criteria of the European Academy of Paediatric Dentistry (EAPD), children aged between 8 and 16 years who were users of the dental services at 8 primary oral health units of the Madrid Health Service (SERMAS) were included. The children underwent a dental examination, and the parents were asked to complete a questionnaire. RESULTS: The prevalence of MIH was 28.63% (CI: 24.61-32.65%). The age cohorts most affected by MIH were 8 years (21.4%) and 11 years (20.7%). The presence of MIH was greater among girls (85; 60.71%) than among boys (55; 39.28%). The mean number of affected teeth per patient was 4.46 ± 2.8. The most frequently affected molar was the upper right first molar (74.3%), and the upper left central incisor was the most affected incisor (37.85%). Opacities were the defects most frequently recorded (63.57%). CONCLUSIONS: The prevalence of MIH in this study is the highest of all relevant studies conducted in Spain.


Asunto(s)
Hipoplasia del Esmalte Dental , Hipomineralización Molar , Niño , Masculino , Femenino , Humanos , Adolescente , Hipoplasia del Esmalte Dental/epidemiología , Estudios Transversales , Prevalencia , Esmalte Dental
13.
Pediatr Infect Dis J ; 43(3): e81-e83, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38381955

RESUMEN

The prevalence of post-COVID-19 condition is not well defined. We describe a cohort of 244 children diagnosed with COVID-19 and followed up for 6 months, in which 4.9% of patients had persistent symptoms at 12 weeks. Anosmia was the most frequent symptom. Being female and having more than 3 symptoms in acute infection were associated with an increased risk of post-COVID.


Asunto(s)
COVID-19 , Humanos , Femenino , Niño , Masculino , Prevalencia , COVID-19/epidemiología , Síndrome Post Agudo de COVID-19 , Enfermedad Crónica , Factores de Riesgo , Hospitales
14.
Cell Stem Cell ; 31(3): 378-397.e12, 2024 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-38402617

RESUMEN

Mechanisms governing the maintenance of blood-producing hematopoietic stem and multipotent progenitor cells (HSPCs) are incompletely understood, particularly those regulating fate, ensuring long-term maintenance, and preventing aging-associated stem cell dysfunction. We uncovered a role for transitory free cytoplasmic iron as a rheostat for adult stem cell fate control. We found that HSPCs harbor comparatively small amounts of free iron and show the activation of a conserved molecular response to limited iron-particularly during mitosis. To study the functional and molecular consequences of iron restriction, we developed models allowing for transient iron bioavailability limitation and combined single-molecule RNA quantification, metabolomics, and single-cell transcriptomic analyses with functional studies. Our data reveal that the activation of the limited iron response triggers coordinated metabolic and epigenetic events, establishing stemness-conferring gene regulation. Notably, we find that aging-associated cytoplasmic iron loading reversibly attenuates iron-dependent cell fate control, explicating intervention strategies for dysfunctional aged stem cells.


Asunto(s)
Hematopoyesis , Hierro , Hematopoyesis/genética , Hierro/metabolismo , Células Madre Hematopoyéticas/metabolismo , Células Madre Multipotentes/metabolismo , Regulación de la Expresión Génica , Diferenciación Celular
15.
Nat Rev Chem ; 8(3): 159-178, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38388837

RESUMEN

The functions of electrochemical energy conversion and storage devices rely on the dynamic junction between a solid and a fluid: the electrochemical interface (EI). Many experimental techniques have been developed to probe the EI, but they provide only a partial picture. Building a full mechanistic understanding requires combining multiple probes, either successively or simultaneously. However, such combinations lead to important technical and theoretical challenges. In this Review, we focus on complementary optoelectronic probes and modelling to address the EI across different timescales and spatial scales - including mapping surface reconstruction, reactants and reaction modulators during operation. We discuss how combining these probes can facilitate a predictive design of the EI when closely integrated with theory.

16.
Nat Rev Chem ; 8(3): 195-210, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38396010

RESUMEN

Catalytic reactions involving molecular hydrogen are at the heart of many transformations in the chemical industry. Classically, hydrogenations are carried out on Pd, Pt, Ru or Ni catalysts. However, the use of supported Au catalysts has garnered attention in recent years owing to their exceptional selectivity in hydrogenation reactions. This is despite the limited understanding of the physicochemical aspects of hydrogen activation and reaction on Au surfaces. A rational design of new improved catalysts relies on making better use of the hydrogenating properties of Au. This Review analyses the strategies utilized to improve hydrogen-Au interactions, from addressing the importance of the Au particle size to exploring alternative mechanisms for H2 dissociation on Au cations and Au-ligand interfaces. These insights hold the potential to drive future applications of Au catalysis.

17.
NPJ Vaccines ; 9(1): 48, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38413645

RESUMEN

Age is associated with reduced efficacy of vaccines and linked to higher risk of severe COVID-19. Here we determined the impact of ageing on the efficacy of a SARS-CoV-2 vaccine based on a stabilised Spike glycoprotein (S-29) that had previously shown high efficacy in young animals. Thirteen to 18-month-old golden Syrian hamsters (GSH) and 22-23-month-old K18-hCAE2 mice were immunised twice with S-29 protein in AddaVaxTM adjuvant. GSH were intranasally inoculated with SARS-CoV-2 either two weeks or four months after the booster dose, while all K18-hACE2 mice were intranasally inoculated two weeks after the second immunisation. Body weight and clinical signs were recorded daily post-inoculation. Lesions and viral load were investigated in different target tissues. Immunisation induced seroconversion and production of neutralising antibodies; however, animals were only partially protected from weight loss. We observed a significant reduction in the amount of viral RNA and a faster viral protein clearance in the tissues of immunized animals. Infectious particles showed a faster decay in vaccinated animals while tissue lesion development was not altered. In GSH, the shortest interval between immunisation and inoculation reduced RNA levels in the lungs, while the longest interval was equally effective in reducing RNA in nasal turbinates; viral nucleoprotein amount decreased in both tissues. In mice, immunisation was able to improve the survival of infected animals. Despite the high protection shown in young animals, S-29 efficacy was reduced in the geriatric population. Our research highlights the importance of testing vaccine efficacy in older animals as part of preclinical vaccine evaluation.

18.
Adv Mater ; 36(5): e2307991, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37757786

RESUMEN

Ultra-high-density single-atom catalysts (UHD-SACs) present unique opportunities for harnessing cooperative effects between neighboring metal centers. However, the lack of tools to establish correlations between the density, types, and arrangements of isolated metal atoms and the support surface properties hinders efforts to engineer advanced material architectures. Here, this work precisely describes the metal center organization in various mono- and multimetallic UHD-SACs based on nitrogen-doped carbon (NC) supports by coupling transmission electron microscopy with tailored machine-learning methods (released as a user-friendly web app) and density functional theory simulations. This approach quantifies the non-negligible presence of multimers with increasing atom density, characterizes the size and shape of these low-nuclearity clusters, and identifies surface atom density criteria to ensure isolation. Further, it provides previously inaccessible experimental insights into coordination site arrangements in the NC host, uncovering a repulsive interaction that influences the disordered distribution of metal centers in UHD-SACs. This observation holds in multimetallic systems, where chemically-specific analysis quantifies the degree of intermixing. These fundamental insights into the materials chemistry of single-atom catalysts are crucial for designing catalytic systems with superior reactivity.

20.
Angew Chem Int Ed Engl ; 63(8): e202317343, 2024 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-38117671

RESUMEN

The implementation of supported metal catalysts heavily relies on the synergistic interactions between metal nanoparticles and the material they are dispersed on. It is clear that interfacial perimeter sites have outstanding skills for turning catalytic reactions over, however, high activity and selectivity of the designed interface-induced metal distortion can also obtain catalysts for the most crucial industrial processes as evidenced in this paper. Herein, the beneficial synergy established between designed Pt nanoparticles and MnO in the course of the reverse water gas shift (RWGS) reaction resulted in a Pt/MnO catalyst having ≈10 times higher activity compared to the reference Pt/SBA-15 catalyst with >99 % CO selectivity. Under activation, a crystal assembly through the metallic Pt (110) and MnO evolved, where the plane distance differences caused a mismatched-row structure in softer Pt nanoparticles, which was identified by microscopic and surface-sensitive spectroscopic characterizations combined with density functional theory simulations. The generated edge dislocations caused the Pt lattice expansion which led to the weakening of the Pt-CO bond. Even though MnO also exhibited an adverse effect on Pt by lowering the number of exposed metal sites, rapid desorption of the linearly adsorbed CO species governed the performance of the Pt/MnO in the RWGS.

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