Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
1.
Respir Res ; 25(1): 48, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38243237

RESUMO

BACKGROUND: Neutrophil extracellular traps (NETs) have repeatedly been related to COVID-19 severity and mortality. However, there is no consensus on their quantification, and there are scarce data on their evolution during the disease. We studied circulating NET markers in patients with COVID-19 throughout their hospitalization. METHODS: We prospectively included 93 patients (201 blood samples), evaluating the disease severity in 3 evolutionary phases (viral, early, and late inflammation). Of these, 72 had 180 samples in various phases. We also evaluated 55 controls with similar age, sex and comorbidities. We measured 4 NET markers in serum: cfDNA, CitH3, and MPO-DNA and NE-DNA complexes; as well as neutrophil-related cytokines IL-8 and G-CSF. RESULTS: The COVID-19 group had higher CitH3 (28.29 vs 20.29 pg/mL, p = 0.022), and cfDNA, MPO-DNA, and NE-DNA (7.87 vs 2.56 ng/mL; 0.80 vs 0.52 and 1.04 vs 0.72, respectively, p < 0.001 for all) than the controls throughout hospitalisation. cfDNA was the only NET marker clearly related to severity, and it remained higher in non-survivors during the 3 phases. Only cfDNA was an independent risk factor for mortality and need for intensive care. Neutrophil count, IL-8, and G-CSF were significantly related to severity. MPO-DNA and NE-DNA showed significant correlations (r: 0.483, p < 0.001), including all 3 phases and across all severity grades, and they only remained significantly higher on days 10-16 of evolution in those who died. Correlations among the other NET markers were lower than expected. CONCLUSIONS: The circulating biomarkers of NETs were present in patients with COVID-19 throughout hospitalization. cfDNA was associated with severity and mortality, but the three other markers showed little or no association with these outcomes. Neutrophil activity and neutrophil count were also associated with severity. MPO-DNA and NE-DNA better reflected NET formation. cfDNA appeared to be more associated with overall tissue damage; previous widespread use of this marker could have overestimated the relationship between NETs and severity. Currently, there are limitations to accurate NET markers measurement that make it difficult to assess its true role in COVID-19 pathogenesis.


Assuntos
COVID-19 , Ácidos Nucleicos Livres , Armadilhas Extracelulares , Humanos , Estudos Longitudinais , COVID-19/patologia , Interleucina-8 , Neutrófilos/patologia , Biomarcadores , DNA , Fator Estimulador de Colônias de Granulócitos
2.
Respir Res ; 24(1): 125, 2023 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-37147677

RESUMO

BACKGROUND: Severe COVID-19 entails a dysregulated immune response, most likely inflammation related to a lack of virus control. A better understanding of immune toxicity, immunosuppression balance, and COVID-19 assessments could help determine whether different clinical presentations are driven by specific types of immune responses. The progression of the immune response and tissular damage could predict outcomes and may help in the management of patients. METHODS: We collected 201 serum samples from 93 hospitalised patients classified as moderately, severely, and critically ill. We differentiated the viral, early inflammatory, and late inflammatory phases and included 72 patients with 180 samples in separate stages for longitudinal study and 55 controls. We studied selected cytokines, P-selectin, and the tissue damage markers lactate dehydrogenase (LDH) and cell-free DNA (cfDNA). RESULTS: TNF-α, IL-6, IL-8, and G-CSF were associated with severity and mortality, but only IL-6 increased since admission in the critical patients and non-survivors, correlating with damage markers. The lack of a significant decrease in IL-6 levels in the critical patients and non-survivors in the early inflammatory phase (a decreased presence in the other patients) suggests that these patients did not achieve viral control on days 10-16. For all patients, lactate dehydrogenase and cfDNA levels increased with severity, and cfDNA levels increased in the non-survivors from the first sample (p = 0.002) to the late inflammatory phase (p = 0.031). In the multivariate study, cfDNA was an independent risk factor for mortality and ICU admission. CONCLUSIONS: The distinct progression of IL-6 levels in the course of the disease, especially on days 10-16, was a good marker of progression to critical status and mortality and could guide the start of IL-6 blockade. cfDNA was an accurate marker of severity and mortality from admission and throughout COVID-19 progression.


Assuntos
COVID-19 , Ácidos Nucleicos Livres , Humanos , Interleucina-6 , Estudos Longitudinais , Hospitalização , Lactato Desidrogenases , Biomarcadores
3.
PLoS One ; 19(6): e0306189, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38924007

RESUMO

The Tropical Andes, one of the world's most biodiverse regions, is vital for ecological research and conservation. However, while researchers in Bolivia, Ecuador, and Peru contribute significantly to scientific knowledge, their publication rates in academic journals have historically lagged behind neighboring nations. A multifaceted strategy was employed to understand and address the publication divide in the Tropical Andes region. This approach focused on regional researchers and consisted of a three-day workshop to improve scientific writing skills, offer publication insights, and equip researchers with tools to overcome obstacles. A series of surveys were also conducted to explore the challenges faced by local researchers and their proposed solutions, covering topics such as participant demographics, factors contributing to lower publication rates, personal barriers, proposed strategies for improving publications, specific topics of interest, participant satisfaction, most valuable workshop topics, and future recommendations. The workshop had an overwhelming response, with over 500 interested participants registering in just a few days, mostly experienced professionals, highlighting the need for such initiatives in the region. About two-thirds had ready-to-publish materials, highlighting the potential impact of targeted interventions on unlocking untapped knowledge. The surveys revealed the challenges contributing to the publication divide, including insufficient training, cultural emphasis on economic development, language barriers, limited resource access, lack of institutional support, high publishing costs, and time and financial constraints. The most common personal barriers were insufficient knowledge and experience in the publication process, lack of self-confidence, and fears of rejection. Proposed solutions include conducting training workshops, fostering collaborative networks, improving resource accessibility, and an institutional and cultural shift that encourages publishing. Addressing challenges faced by experienced professionals in the Tropical Andes by understanding individual needs, fostering support, and demystifying the publication process offers a promising path to closing the publication divide and unlocking the region's valuable scientific contributions.


Assuntos
Pesquisadores , Humanos , Pesquisadores/psicologia , Peru , Bolívia , Equador , Publicações/estatística & dados numéricos , Editoração
4.
J Am Chem Soc ; 135(27): 10091-8, 2013 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-23763580

RESUMO

We study how the (100) surface of magnetite undergoes oxidation by monitoring its morphology during exposure to oxygen at ~650 °C. Low-energy electron microscopy reveals that magnetite's surface steps advance continuously. This growth of Fe3O4 crystal occurs by the formation of bulk Fe vacancies. Using Raman spectroscopy, we identify the sinks for these vacancies, inclusions of α-Fe2O3 (hematite). Since the surface remains magnetite during oxidation, it continues to dissociate oxygen readily. At steady state, over one-quarter of impinging oxygen molecules undergo dissociative adsorption and eventual incorporation into magnetite. From the independence of growth rate on local step density, we deduce that the first step of oxidation, dissociative oxygen adsorption, occurs uniformly over magnetite's terraces, not preferentially at its surface steps. Since we directly observe new magnetite forming when it incorporates oxygen, we suggest that catalytic redox cycles on magnetite involve growing and etching crystal.


Assuntos
Óxido Ferroso-Férrico/química , Catálise , Oxirredução , Análise Espectral Raman , Propriedades de Superfície
5.
J Fungi (Basel) ; 8(4)2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35448599

RESUMO

The cell wall integrity (CWI) MAPK pathway of budding yeast Saccharomyces cerevisiae is specialized in responding to cell wall damage, but ongoing research shows that it participates in many other stressful conditions, suggesting that it has functional diversity. The output of this pathway is mainly driven by the activity of the MAPK Slt2, which regulates important processes for yeast physiology such as fine-tuning of signaling through the CWI and other pathways, transcriptional activation in response to cell wall damage, cell cycle, or determination of the fate of some organelles. To this end, Slt2 precisely phosphorylates protein substrates, modulating their activity, stability, protein interaction, and subcellular localization. Here, after recapitulating the methods that have been employed in the discovery of proteins phosphorylated by Slt2, we review the bona fide substrates of this MAPK and the growing set of candidates still to be confirmed. In the context of the complexity of MAPK signaling regulation, we discuss how Slt2 determines yeast cell integrity through phosphorylation of these substrates. Increasing data from large-scale analyses and the available methodological approaches pave the road to early identification of new Slt2 substrates and functions.

6.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1440266

RESUMO

Objetivo: estudiar y comparar la inclinación de la cabeza entre niños con dentición primaria completa y dentición mixta primera fase. Materiales y métodos: el estudio incluyó a 80 voluntarios entre 4 y 9 años, a quienes se les tomó una fotografía facial de perfil derecho estandarizada, en Posición Natural de Cabeza. Éstas fueron analizadas mediante software de edición de imágenes para determinar la inclinación de la cabeza de cada voluntario. Para ello, se definió un plano (plano t-ex) formado por el punto Intertrágico (t) y Exocanto (ex) y se comparó respecto a la horizontal verdadera. Los datos obtenidos fueron tabulados, clasificados en dos grupos según el tipo de dentición y analizados estadísticamente. Resultados: el promedio de inclinación del plano t-ex fue de 22,7º en el grupo de niños con dentición primaria completa y de 25,8º en el grupo de niños con dentición mixta primera fase. La diferencia entre ambos grupos fue de 3,1º, con significancia estadística (p = 0,006). Conclusión: la inclinación de la cabeza de los niños con dentición mixta primera fase es mayor en sentido antihorario, respecto a la de los niños con dentición primaria completa.


Objective: to study and compare head tilt among children with complete primary dentition and first transitional period of the mixed dentition stage. Materials and methods: the study included 80 volunteers between 4 and 9 years of age, who were taken a standardized right profile facial photograph in a Natural Head Position. These photographs were analyzed using image editing software to determine the head tilt of each volunteer. For this, a plane (plane t-ex) formed by the Intertragic point (t) and Exocanth (ex) was defined and compared with respect to the true horizontal. The data obtained were tabulated, classified into two groups according to the type of dentition and statistically analyzed. Results: the average t-ex plane inclination was 22.7º in the group of children with complete primary dentition and 25.8º in the group of children with first transitional period of the mixed dentition stage. The difference between both groups was 3.1º, with statistical significance (p = 0.006). Conclusion: the head tilt of children with first transitional period of the mixed dentition stage is greater in an anti-clockwise direction, compared to that of children with complete primary dentition.

7.
Artigo em Inglês | MEDLINE | ID: mdl-18051171

RESUMO

In this paper we describe a method to assess the piezoelectric response of a piezoelectric thin film deposited on a conductive substrate. It is based on analyzing the frequency response of a surface acoustic wave (SAW) filter made on the piezoelectric thin film. For this analysis, we use a circuital model that takes into account the theoretical response of the ideal filter along with all the external and internal parasitic effects that deteriorate the response. Using this model, we can obtain the electromechanical coupling factor of the piezoelectric material (k2m) with good accuracy. If parasitic effects are not considered, k2m can be underestimated by a factor of up to 20. We have tested our model using SAW filters made on A1N thin films sputtered on substrates with different conductivities. A discussion on the relation between the different circuital elements and the physical properties of the filters also is provided.

8.
Int. j interdiscip. dent. (Print) ; 14(3): 218-221, dic. 2021. tab, ilus
Artigo em Espanhol | LILACS | ID: biblio-1385221

RESUMO

RESUMEN: Objetivo: el objetivo de este estudio fue determinar la discrepancia del Plano de Frankfurt evaluado en fotogrametría y en cefalometría de radiografías laterales de cráneo respecto a la horizontal verdadera. Materiales y métodos: el estudio consideró a 34 voluntarios de la clínica del Postítulo de Ortodoncia y Ortopedia Dento Máxilo Facial de la Facultad de Odontología de la Universidad de Chile. Se utilizaron sus radiografías laterales de cráneo orientadas según el Plano de Frankfurt paralelo al piso y se les tomó una fotografía facial de perfil estandarizada en Posición Natural de Cabeza. Se trazó el Plano de Frankfurt y la Horizontal Verdadera en ambos exámenes y se midió el ángulo formado entre estos planos. Resultados: al comparar los ángulos mediante T-test, no hubo diferencia estadística. Conclusiones: mediante la aplicación de un protocolo sistematizado tanto para el registro fotográfico como para la obtención de la Posición Natural de Cabeza, se puede lograr que el Plano de Frankfurt sea prácticamente coincidente en radiografías laterales de cráneo y en fotografías clínicas, demostrando su uso hasta el día de hoy en la ortodoncia moderna.


ABSTRACT: Objective: the aim of this study was to determine the Frankfurt plane variation evaluated in photogrammetry and lateral skull x-ray cephalometry in relation to the true horizontal. Materials and methods: the study included 34 volunteers from the Universidad de Chile Dento-maxillofacial Orthodontics and Orthopedics Postgraduate Clinic. Their lateral skull radiographs, oriented according to the Frankfurt Plane parallel to the floor, were used and a standardized profile facial photograph was taken in Natural Head Position. The Frankfurt Plane and True Horizontal were drawn in both examinations and the angle formed between these planes was measured. Results: when comparing the angles through T-test, there was no statistical difference. Conclusions: through the application of a systematized protocol for both photographic record and natural head position obtained, the Frankfurt Plane can be practically coincident in lateral skull x-rays and clinical photographs, showing its usefulness up to the present days in modern orthodontics.


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Crânio , Fotogrametria , Cefalometria
9.
Artigo em Inglês | MEDLINE | ID: mdl-15128222

RESUMO

We present a study of the effect of particle bombardment on the preferred orientation and the residual stress of polycrystalline aluminum nitride (AlN) thin films for surface acoustic wave (SAW) applications. Films were deposited on silicon (100) substrates by radio frequency (RF) sputtering of an aluminum target in an argon and nitrogen gas mixture. The main deposition parameters were changed as follows: the total pressure from 4 mTorr to 11 mTorr, the N2 content in the gas mixture from 20% to 80%, and the substrate self-bias voltage from -10 V to -30 V. If a sufficiently high negative substrate self-bias voltage is induced, (00.2)-oriented films are obtained over the full ranges of pressure and N2 content. Such films have values of residual stress ranging from -3 GPa to +1 GPa, depending on the deposition conditions. Our results suggest that the energy of the Ar ions colliding with the substrate controls the preferred orientation of the films, whereas the directionality of the ions (for the same energy) is the main factor determining the residual stress. To demonstrate the suitability of our material for the intended application, SAW filters with good electroacoustic response have been fabricated using AlN thin films with optimized (00.2) orientation and controlled residual stress.

10.
Ultramicroscopy ; 130: 77-81, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23528222

RESUMO

Spin-polarized low-energy electron microscopy was used to image a magnetite crystal with (001) surface orientation. Sets of spin-dependent images of magnetic domain patterns observed in this surface were used to map the direction of the magnetization vector with high spatial and angular resolution. We find that domains are magnetized along the surface <110> directions, and domain wall structures include 90° and 180° walls. A type of unusually curved domain walls are interpreted as Néel-capped surface terminations of 180° Bloch walls.

11.
Artigo em Inglês | MEDLINE | ID: mdl-20040422

RESUMO

In this paper we describe the procedure to sputter low acoustic impedance SiO(2) films to be used as a low acoustic impedance layer in Bragg mirrors for BAW resonators. The composition and structure of the material are assessed through infrared absorption spectroscopy. The acoustic properties of the films (mass density and sound velocity) are assessed through X-ray reflectometry and picosecond acoustic spectroscopy. A second measurement of the sound velocity is achieved through the analysis of the longitudinal lambda/2 resonance that appears in these silicon oxide films when used as uppermost layer of an acoustic reflector placed under an AlN-based resonator.


Assuntos
Acústica/instrumentação , Lentes , Sistemas Microeletromecânicos/instrumentação , Refratometria/instrumentação , Dióxido de Silício/química , Transdutores , Desenho Assistido por Computador , Impedância Elétrica , Desenho de Equipamento , Análise de Falha de Equipamento , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Vibração
12.
s.l; ICFES; 1984. 20 p.
Monografia em Espanhol | LILACS | ID: lil-101917

RESUMO

El presente estudio realizado en el Valle de Aburra, Departamento de Antioquia, tuvo como propiedad identificar las empresas interesadas en vicular profesional de enfermeria para desarrollar los programas de salud ocupacional , determinar la existencia de este recurso dentro de las factorias y proponer un modelo normativo de las funciones y actividades de enfermeria en salud ocupacional y un programa de capacitacion para estos profesionales. Para ello, se realizo una encuesta dirigida a empresario, con una parte introductoria, donde se resumen las actividades que puede ejecutar el profesional de enfermeria en la industria y el formulario respectivo. La poblacion y muestra del estudio la constituyeron 74 empresas con mas de 200 trabajadores y de mayor riesgo laboral. Se encontro que la mayor proporcion de ellas son textileras y manufactureras, 37.5% y 22.2% respectivamente; 90% realizan actividades de salud ocupacional, siendo las mas prevalentes prestacion de primeros auxilios y prevencion de accidentes. Solo 4 industrias tenian servicios de enfermeria profesional con funciones basicamente asistenciales. 50% de estas companias respondieron afirmativamente a la contratacion de este recurso luego de conocer su labor.


Assuntos
Enfermagem do Trabalho/normas , Enfermagem do Trabalho , Enfermeiras e Enfermeiros/estatística & dados numéricos , Colômbia , Indústrias
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA