Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 71
Filtrar
1.
Rev Esp Anestesiol Reanim (Engl Ed) ; 69(8): 493-496, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36088269

RESUMO

Tarlov cysts are a pathological dilatation of the meninges. Their incidence is more frequent in women between 30 and 50 years of age. The imaging test of choice for diagnosis is MRI. Of unknown etiology, most cases are asymptomatic, but symptoms of radicular irritation, among others, may occur. The therapeutic possibilities are multiple, reserving surgical excision as the last option. We report a case of successful spinal anaesthesia for elective cesarean section in a patient with a giant Tarlov cyst but with potential airway compromise, in whom the risks of general anaesthesia would be increased. Anaesthetic management presents a challenge for the anesthesiologist, especially in situations where the patient presents an increased anaesthetic risk for general anaesthesia, as is the case in the obstetric patient.


Assuntos
Raquianestesia , Anestésicos , Cistos de Tarlov , Cesárea , Feminino , Humanos , Imageamento por Ressonância Magnética , Gravidez , Cistos de Tarlov/epidemiologia , Cistos de Tarlov/patologia , Cistos de Tarlov/cirurgia
2.
Eur J Nutr ; 59(7): 2893-2904, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31701336

RESUMO

PURPOSE: Advanced glycation end products (AGEs) can be formed in foods by the reaction of reducing sugars with proteins, and have been shown to induce insulin resistance and obesity in experimental studies. We examined the association between dietary AGEs intake and changes in body weight in adults over an average of 5 years of follow-up. METHODS: A total of 255,170 participants aged 25-70 years were recruited in ten European countries (1992-2000) in the PANACEA study (Physical Activity, Nutrition, Alcohol, Cessation of smoking, Eating out of home in relation to Anthropometry), a sub-cohort of the EPIC (European Prospective Investigation into Cancer and Nutrition). Body weight was measured at recruitment and self-reported between 2 and 11 years later depending on the study center. A reference database for AGEs was used containing UPLC-MS/MS-measured Nε-(carboxymethyl)-lysine (CML), Nε-(1-carboxyethyl)-lysine (CEL), and Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) in 200 common European foods. This reference database was matched to foods and decomposed recipes obtained from country-specific validated dietary questionnaires in EPIC and intake levels of CEL, CML, and MG-H1 were estimated. Associations between dietary AGEs intake and body weight change were estimated separately for each of the three AGEs using multilevel mixed linear regression models with center as random effect and dietary AGEs intake and relevant confounders as fixed effects. RESULTS: A one-SD increment in CEL intake was associated with 0.111 kg (95% CI 0.087-0.135) additional weight gain over 5 years. The corresponding additional weight gain for CML and MG-H1 was 0.065 kg (0.041-0.089) and 0.034 kg (0.012, 0.057), respectively. The top six food groups contributing to AGEs intake, with varying proportions across the AGEs, were cereals/cereal products, meat/processed meat, cakes/biscuits, dairy, sugar and confectionary, and fish/shellfish. CONCLUSION: In this study of European adults, higher intakes of AGEs were associated with marginally greater weight gain over an average of 5 years of follow-up.


Assuntos
Peso Corporal , Dieta , Produtos Finais de Glicação Avançada , Adulto , Cromatografia Líquida , Europa (Continente) , Humanos , Estudos Prospectivos , Espectrometria de Massas em Tandem
3.
Enferm. univ ; 16(2): 157-170, abr.-jun. 2019. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS, BDENF - Enfermagem | ID: biblio-1012019

RESUMO

Resumen Introducción: En Chile, las enfermeras/os tienen respaldo legal para gestionar el cuidado, esto facilita el desarrollo de competencias para ejercer autonomía y liderazgo. Actualmente persisten barreras para transitar hacia un reconocimiento real de la independencia profesional. Objetivo: Develar la experiencia vivida de enfermeras con cargos en niveles de jefatura respecto al propio desarrollo para lograr el liderazgo y autonomía profesional. Metodología: Estudio cualitativo, descriptivo-interpretativo, desde la trayectoria fenomenológica de Edmund Husserl. Muestreo selectivo de caso homogéneo de tres enfermeras que desempeñaban rol de jefatura en instituciones de salud, región Valparaíso, Chile. Participación consentida. Entrevista no estructurada. Análisis del discurso utilizando el modelo de liderazgo integral de Ken Wilber. Resultados: Categorías: Conciencia del líder «ser inquieta...intelectualmente¼. Construyendo competencias «el liderazgo se aprende¼. Transitando hacia el ejercicio de la autonomía y el liderazgo, "para el posicionamiento hay que luchar". El peso de las estructuras organizacionales «tu rol es parte de un hospital¼. Interpretación: El ejercicio del liderazgo y la autonomía se fundamenta en competencias actitudinales por sobre las cognitivas y técnicas. Existe mayor apoyo y reconocimiento a nivel institucional, que al interior del equipo de salud. Persisten limitaciones para lograr máxima expresión del liderazgo y autonomía, por persistencia de modelos institucionales hegemónicos, centrados en decisiones médicas y desconocimiento del rol integrado. Conclusión: El líder se mueve en un escenario dual, entre un menor reconocimiento del equipo y un creciente empoderamiento del rol autónomo y visibilidad a nivel directivo institucional.


Abstract Introduction: In Chile, nurses have legal support to manage care, a situation which facilitates the development of competencies to perform with autonomy and leadership; however, barriers still persist while moving towards a real acknowledgement of professional independency. Objective: To unveil the lived experience of nurses in executive roles regarding their own development towards leadership and professional autonomy. Methodology: This is a descriptive and interpretative qualitative study framed by the Edmund Husserl phenomenological approach. The sample by homogeneous case included three nurses in executive roles in health institutions in Valparaiso, Chile. The participation was by consent. An unstructured interview was used. For the discourse analysis, the Ken Wilber integral leadership model was followed. Results: Categories: Leadership awareness <being inquiring… intellectually>… Building Competencies <leadership is learned>. Moving towards the practice of autonomy and leadership, "positioning requires striving". Weight of the organizational structures <your role is part of a hospital>. Interpretation: A practice of leadership and autonomy is based on attitude competencies over the cognitive and technical ones. Nevertheless, there still persist limitations to achieve a maximal expression of leadership and autonomy due to hegemonic institutional models which focus on medical decisions and neglect the integrated roles. Conclusion: The leader moves in a dual setting between a lower acknowledgement from the team, and a higher empowerment of the autonomous role and the visibility at the institutional directive level.


Resumo Introdução: No Chile, as enfermeiras/os têm apoio legal para gerenciar o cuidado, isto facilita o desenvolvimento de competências para exercer autonomia e liderança. Atualmente, persistem barreiras para transitar em direção a um reconhecimento real da independência profissional. Objetivo: Desvendar a experiência vivida de enfermeiras com cargos em níveis de chefia ao respeito do próprio desenvolvimento, para atingir a liderança e autonomia profissional. Metodologia: Estudo qualitativo, descritivo-interpretativo, desde a trajetória fenomenológica de Edmund Husserl. Amostragem seletiva de caso homogéneo de três enfermeiras que desempenhavam papel de chefia em instituições de saúde, região Valparaíso, Chile. Participação consentida. Entrevista não estruturada. Análise de discurso, utilizou-se o modelo de liderança integral de Ken Wilber. Resultados: Categorias: Consciência do líder «ser irrequieta...intelectualmente¼. Ir construindo competências «a liderança se aprende¼. Transitar em direção ao exercício da autonomia e a liderança, "para o posicionamento tem que lutar". O peso das estruturas organizacionais «seu rolo é parte de um hospital¼. Interpretação: O Exercício da liderança e a autonomia fundamenta-se em competências atitudinais, sobre as cognitivas e técnicas. Existe maior apoio e reconhecimento a nível institucional, que no interior da equipe de saúde. Persistem limitações para atingir a máxima expressão de liderança e autonomia, por persistência de modelos institucionais hegemónicos, centrados em decisões médicas e desconhecimento do rolo integrado. Conclusão: O líder movimenta-se em um cenário dual, entre um menor reconhecimento da equipe e um empoderamento crescente do rolo autónomo e visibilidade a nível diretivo institucional.

4.
Phys Med Biol ; 64(2): 025011, 2019 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-30524026

RESUMO

Dose and range verification have become important tools to bring carbon ion therapy to a higher level of confidence in clinical applications. Positron emission tomography is among the most commonly used approaches for this purpose and relies on the creation of positron emitting nuclei in nuclear interactions of the primary ions with tissue. Predictions of these positron emitter distributions are usually obtained from time-consuming Monte Carlo simulations or measurements from previous treatment fractions, and their comparison to the current, measured image allows for treatment verification. Still, a direct comparison of planned and delivered dose would be highly desirable, since the dose is the quantity of interest in radiation therapy and its confirmation improves quality assurance in carbon ion therapy. In this work, we present a deconvolution approach to predict dose distributions from PET images in carbon ion therapy. Under the assumption that the one-dimensional PET distribution is described by a convolution of the depth dose distribution and a filter kernel, an evolutionary algorithm is introduced to perform the reverse step and predict the depth dose distribution from a measured PET distribution. Filter kernels are obtained from either a library or are created for any given situation on-the-fly, using predictions of the [Formula: see text]-decay and depth dose distributions, and the very same evolutionary algorithm. The applicability of this approach is demonstrated for monoenergetic and polyenergetic carbon ion irradiation of homogeneous and heterogeneous solid phantoms as well as a patient computed tomography image, using Monte Carlo simulated distributions and measured in-beam PET data. Carbon ion ranges are predicted within less than 0.5 mm and 1 mm deviation for simulated and measured distributions, respectively.


Assuntos
Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/radioterapia , Radioterapia com Íons Pesados/métodos , Processamento de Imagem Assistida por Computador/métodos , Imagens de Fantasmas , Tomografia por Emissão de Pósitrons/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Algoritmos , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Método de Monte Carlo
5.
Prev Med ; 114: 149-155, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29958860

RESUMO

In a cross-sectional study carried out in El Salvador between February 2016 and July 2017, self-sampling and human papillomavirus (HPV) testing was found to be highly acceptable among 2019 women who had not attended a cervical cancer screening in at least 3 years. Within this population, HPV positivity rates differed according to age, marital status, number of children, and lifetime sexual partners. The proportion of women who tested HPV positive or who were diagnosed with cervical intraepithelial neoplasia grade 2 (CIN2) or more severe diagnoses (CIN2+) was similar to the general population of the area. Among the reasons for failing to participate in previous screening programs, non-attending women described logistic concerns, but also erroneous beliefs regarding HPV and cervical cancer, misconceptions regarding the screening procedure, discomfort with male providers, and confidentiality fears. The aim of this study was to identify opportunities and challenges that emerged from the use of self-sampling and HPV testing as part of a public cervical cancer control effort in a low-resource setting.


Assuntos
Detecção Precoce de Câncer , Infecções por Papillomavirus/diagnóstico , Manejo de Espécimes/métodos , Displasia do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/prevenção & controle , Adulto , Estudos Transversais , Detecção Precoce de Câncer/métodos , El Salvador , Feminino , Humanos , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Papillomaviridae/isolamento & purificação , População Rural , Esfregaço Vaginal/métodos
6.
Phys Rev Lett ; 119(5): 053204, 2017 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-28949751

RESUMO

Studies of strong field ionization have historically relied on the strong field approximation, which neglects all spatial dependence in the forces experienced by the electron after ionization. More recently, the small spatial inhomogeneity introduced by the long-range Coulomb potential has been linked to a number of important features in the photoelectron spectrum, such as Coulomb asymmetry, Coulomb focusing, and the low energy structure. Here, we demonstrate using midinfrared laser wavelength that a time-varying spatial dependence in the laser electric field, such as that produced in the vicinity of a nanostructure, creates a prominent higher energy peak. This higher energy structure (HES) originates from direct electrons ionized near the peak of a single half-cycle of the laser pulse. The HES is separated from all other ionization events, with its location and width highly dependent on the strength of spatial inhomogeneity. Hence, the HES can be used as a sensitive tool for near-field characterization in the "intermediate regime," where the electron's quiver amplitude is comparable to the field decay length. Moreover, the large accumulation of electrons with tuneable energy suggests a promising method for creating a localized source of electron pulses of attosecond duration using tabletop laser technology.

7.
Opt Express ; 25(13): 14974-14985, 2017 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-28788933

RESUMO

Plasmon resonances are known to amplify the electromagnetic fields near metallic nanostructures, providing a promising scheme to generate extreme-ultraviolet harmonics using low power drivings. During high-order harmonic generation (HHG), the driving and harmonic fields accumulate a phase difference as they propagate through the target. In a typical set-up -a laser focused into a gas jet- the propagation distances amount to several wavelengths, and the cumulative phase-mismatch affects strongly the efficiency and properties of the harmonic emission. In contrast, HHG in metallic nanostructures is considered to overcome these limitations, as the common sources of phase mismatch -optical density and focusing geometry- are negligible for subwavelength propagation distances. We demonstrate that phase matching still plays a relevant role in HHG from nanostructures due to the non-perturbative character of HHG, that links the harmonic phase to the intensity distribution of the driving field. Our computations show that widely used applications of phase matching control, such as quantum path selection and the increase of contrast in attosecond pulse generation, are also feasible at the nanoscale.

8.
J Phys Condens Matter ; 29(28): 285301, 2017 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-28594639

RESUMO

An ambipolar n-p double quantum dot defined by potential variation along a semiconducting carbon-nanotube is considered. We focus on the (1e,1h) charge configuration with a single excess electron of the conduction band confined in the n-type dot and a single missing electron in the valence band state of the p-type dot for which lifting of the Pauli blockade of the current was observed in the electric-dipole spin resonance (Laird et al 2013 Nat. Nanotechnol. 8 565). The dynamics of the system driven by periodic electric field is studied with the Floquet theory and the time-dependent configuration interaction method with the single-electron spin-valley-orbitals determined for atomistic tight-binding Hamiltonian. We find that the transitions lifting the Pauli blockade are strongly influenced by coupling to a vacuum state with an empty n dot and a fully filled p dot. The coupling shifts the transition energies and strongly modifies the effective g factors for axial magnetic field. The coupling is modulated by the bias between the dots but it appears effective for surprisingly large energy splitting between the (1e,1h) ground state and the vacuum (0e, 0h) state. Multiphoton transitions and high harmonic generation effects are also discussed.

9.
Phys Chem Chem Phys ; 19(12): 8363-8372, 2017 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-28280810

RESUMO

Single domain superparamagnetic ferrite nanoparticles with the composition MFe2O4 (M = Fe, Co, Zn) have been prepared by thermal decomposition of metal acetylacetonates in diphenyl ether or dibenzyl ether, using oleic acid in the presence of oleylamine as a stabilizing agent. The Fe, Co and Zn ferrite nanoparticles are monodisperse with diameters of 4.9, 4.4 and 4.7 nm, respectively. The TG and IR results indicate that four or six carboxylate groups per nm2 are bonded at the surface of the particles acting as chelating and/or bridging bidentate ligands depending on the composition. The oleate groups minimize the interparticle interactions in Fe and Zn ferrite samples, while in the Co ferrite sample dipolar interactions produce broad maxima in the ZFC and energy barriers distribution curves. The inversion degree has been estimated from the Raman spectra and the obtained x values have been used to calculate the saturation magnetization and compare them with the experimental MS values. Compared to bulk materials, the magnetization value is higher for the Zn ferrite sample due to its mixed spinel cation distribution. For the Co ferrite sample, and probably for the Fe one, the low value of saturation magnetization seems to be due to the surface disordered layer of canted spins. Compared to non-coated nanoparticles with the same composition and similar size, the oleate groups, covalently bonded to the superficial cations, increase the anisotropy field and decrease the magnetization.

10.
Rep Prog Phys ; 80(5): 054401, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28059773

RESUMO

Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto- and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds (1 attosecond = 1 as = 10-18 s), which is comparable with the optical field. For comparison, the revolution of an electron on a 1s orbital of a hydrogen atom is ∼152 as. On the other hand, the second branch involves the manipulation and engineering of mesoscopic systems, such as solids, metals and dielectrics, with nanometric precision. Although nano-engineering is a vast and well-established research field on its own, the merger with intense laser physics is relatively recent. In this report on progress we present a comprehensive experimental and theoretical overview of physics that takes place when short and intense laser pulses interact with nanosystems, such as metallic and dielectric nanostructures. In particular we elucidate how the spatially inhomogeneous laser induced fields at a nanometer scale modify the laser-driven electron dynamics. Consequently, this has important impact on pivotal processes such as above-threshold ionization and high-order harmonic generation. The deep understanding of the coupled dynamics between these spatially inhomogeneous fields and matter configures a promising way to new avenues of research and applications. Thanks to the maturity that attosecond physics has reached, together with the tremendous advance in material engineering and manipulation techniques, the age of atto-nanophysics has begun, but it is in the initial stage. We present thus some of the open questions, challenges and prospects for experimental confirmation of theoretical predictions, as well as experiments aimed at characterizing the induced fields and the unique electron dynamics initiated by them with high temporal and spatial resolution.

11.
Biosens Bioelectron ; 88: 101-108, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-27544786

RESUMO

Magnetic separation based on biologically-modified magnetic particles is a preconcentration procedure commonly integrated in magneto actuated platforms for the detection of a huge range of targets. However, the main drawback of this material is the low stability and high cost. In this work, a novel hybrid molecularly-imprinted polymer with magnetic properties is presented with affinity towards biotin and biotinylated biomolecules. During the synthesis of the magneto core-shell particles, biotin was used as a template. The characterization of this material by microscopy techniques including SEM, TEM and confocal microscopy is presented. The application of the magnetic-MIPs for the detection of biotin and biotinylated DNA in magneto-actuated platforms is also described for the first time. The magnetic-MIP showed a significant immobilization capacity of biotinylated molecules, giving rise to a cheaper and a robust method (it is not required to be stored at 4°C) with high binding capacity for the separation and purification under magnetic actuation of a wide range of biotinylated molecules, and their downstream application including determination of their specific targets.


Assuntos
Biotina/isolamento & purificação , Imãs/química , Impressão Molecular/métodos , Polímeros/química , Biotina/química , Biotinilação , DNA Bacteriano/química , DNA Bacteriano/isolamento & purificação , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Humanos , Imunoensaio/métodos , Magnetismo
14.
J Thromb Haemost ; 13(5): 708-18, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25611553

RESUMO

OBJECTIVE: To assess the risk of non-fatal ischemic stroke associated with non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol. The effects of dose, duration of treatment, background cardiovascular (CV) risk and use of concomitant aspirin were studied. METHODS: We performed a population-based case-control study. Patients were considered exposed if they were on treatment within a 30-day window before the index date. We estimated adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) using logistic regression. RESULTS: Two thousand eight hundred and eighty-eight cases and 20 000 controls were included. No increased risk was observed with traditional NSAIDs as a group (OR = 1.03; 95% CI, 0.90-1.19), but results varied across individual agents and conditions of use. An increased risk was found with diclofenac (OR = 1.53; 95% CI, 1.19-1.97), in particular when used at high doses (OR = 1.62; 1.06-2.46), over long-term periods (> 365 days; OR = 2.39; 1.52-3.76) and in patients with a high background CV risk (OR = 1.78; 1.23-2.58), as well as with aceclofenac when used at high doses (OR = 1.67; 1.05-2.67), in long-term treatments (OR = 2.00; 1.14-3.53) and in patients with CV risk factors (OR = 2.33; 1.40-3.87). No association was found with ibuprofen (OR = 0.94; 0.76-1.17) or naproxen (OR = 0.68; 0.36-1.29). The concomitant use of aspirin did not show a significant effect modification. Paracetamol did not increase the risk overall (OR = 0.97; 0.85-1.10) or in patients at high CV risk (OR = 0.94; 0.78-1.14). CONCLUSIONS: Diclofenac and aceclofenac increase the risk of ischemic stroke while ibuprofen and naproxen do not. Dose, duration and baseline CV risk, but not aspirin use, appear to modulate the risk. Paracetamol does not increase the risk, even in patients with a high background CV risk.


Assuntos
Acetaminofen/efeitos adversos , Anti-Inflamatórios não Esteroides/efeitos adversos , Isquemia Encefálica/induzido quimicamente , Acidente Vascular Cerebral/induzido quimicamente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vigilância da População , Fatores de Risco
15.
Phys Rev Lett ; 115(26): 267202, 2015 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-26765018

RESUMO

We report comprehensive small angle neutron scattering measurements complemented by ac susceptibility data of the helical order, conical phase, and Skyrmion lattice phase (SLP) in MnSi under uniaxial pressures. For all crystallographic orientations uniaxial pressure favors the phase for which a spatial modulation of the magnetization is closest to the pressure axis. Uniaxial pressures as low as 1 kbar applied perpendicular to the magnetic field axis enhance the Skyrmion lattice phase substantially, whereas the Skyrmion lattice phase is suppressed for pressure parallel to the field. Taken together we present quantitative microscopic information on how strain couples to magnetic order in the chiral magnet MnSi.

20.
Science ; 340(6136): 1076-80, 2013 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-23723232

RESUMO

Skyrmion crystals are regular arrangements of magnetic whirls that exist in a wide range of chiral magnets. Because of their topology, they cannot be created or destroyed by smooth rearrangements of the direction of the local magnetization. Using magnetic force microscopy, we tracked the destruction of the skyrmion lattice on the surface of a bulk crystal of Fe(1-x)Co(x)Si (x = 0.5). Our study revealed that skyrmions vanish by a coalescence, forming elongated structures. Numerical simulations showed that changes of topology are controlled by singular magnetic point defects. They can be viewed as quantized magnetic monopoles and antimonopoles, which provide sources and sinks of one flux quantum of emergent magnetic flux, respectively.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA