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1.
Comput Methods Programs Biomed ; 208: 106262, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34260972

RESUMO

The incidence of bone fracture has become a major clinical problem on a worldwide scale. In the past two decades there has been an increase in the use of computational tools to analyse the bone fracture problem. In several works, various study cases have been analysed to compare human and animal bone fracture healing. Unfortunately, there are not many publications about computational advances in this field and the existing approaches to the problem are usually similar. In this context, the objective of this work is the application of a diffusion problem in the model of the bone fragments resulting from fracture, working together with a mesh-growing algorithm that allows free growth of the callus depending on the established conditions, without a pre-meshed domain. The diffusion problem concerns the different biological magnitudes controlling the callus growth, among which Mesenchymal Stem Cells and chondrocytes concentrations were chosen, together with Tumour Necrosis Factor α and Bone Morphogenetic Protein as the factors influencing the velocity in the callus formation. A Finite Element approach was used to solve the corresponding diffusion problems, obtaining the concentration values along the entire domain and allowing detecting the zones in which biological magnitudes reach the necessary thresholds for callus growth. The callus growth is guided by a geometrical algorithm which performs an additional mesh generation process (self-added mesh) at each step of the iterative procedure until complete callus formation. The proposed approach was applied to different types of diaphyseal femoral fractures treated by means of intramedullary nailing. Axisymmetric models based on triangular quadratic elements were used, obtaining results in good agreement with clinical evidence of these kinds of fractures. The algorithm proposed has the advantage of a natural callus growth, without the existence of a previous mesh that may affect the conditions and direction of growth. The approach is intended for the initial phase of callus growth. Future work will address the implementation of the corresponding formulations for tissue transformation and bone remodelling in order to achieve complete fracture healing.


Assuntos
Fraturas do Fêmur , Fixação Intramedular de Fraturas , Algoritmos , Animais , Calo Ósseo , Consolidação da Fratura , Humanos
2.
Injury ; 52 Suppl 4: S61-S70, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33707035

RESUMO

INTRODUCTION: Intramedullary nailing is generally accepted as the first choice for the treatment of diaphyseal fractures of femur and tibia, with a gradual incease in the use of unreamed nails. Different studies during last years show controversial outcomes. Some authors strongly favor unreamed nailing, but most of the authors conclude that reamed nailing have proved to be more successful. MATERIAL AND METHODS: This study simulates unreamed intramedullary nailing of four femoral and three tibial fracture types by means of Finite Element (FE) models, at early postoperative stages with a fraction of physiological loads, in order to determine whether sufficient stability is achieved, and if the extent of movements and strains at the fracture site may preclude proper consolidation. RESULTS: The behavior observed in the different fracture models is very diverse. In the new biomechanical situation, loads are only transmitted through the intramedullary nail. Mean relative displacement values of fractures in the femoral bone range from 0.30 mm to 0.82 mm, depending on the fracture type. Mean relative displacement values of the tibial fractures lie between 0.18 and 0.62 mm, depending on the type of fracture. Concerning mean strains, for femoral fractures the maximum strains ranged between 12.7% and 42.3%. For tibial fractures the maximum strains ranged between 10.9% and 40.8%. CONCLUSIONS: The results showed that unreamed nailing provides a very limited mechanical stability, taking into account that analyzed fracture patterns correspond to simple fracture without comminution. Therefore, unreamed nailing is not a correct indication in femoral fractures and should be an exceptional indication in open tibial fractures produced by high-energy mechanism.


Assuntos
Fraturas do Fêmur , Fixação Intramedular de Fraturas , Fraturas da Tíbia , Pinos Ortopédicos , Fraturas do Fêmur/diagnóstico por imagem , Fraturas do Fêmur/cirurgia , Consolidação da Fratura , Humanos , Extremidade Inferior , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/cirurgia
3.
Phys Chem Chem Phys ; 22(44): 25876-25891, 2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33156308

RESUMO

In this work PbMoO4 and Pb1-2xCaxSrxMoO4 (x = 0.1, 0.2, 0.3, 0.4 and 0.5) solid solutions have been successfully prepared, for the first time, by a simple co-precipitation method and the as-synthesized samples were subjected to a water-based reflux treatment. Structural characterization of these samples was performed using X-ray diffraction with Rietveld refinement analysis and Raman spectroscopy. Their optical properties were investigated by UV-Vis absorption spectroscopy and PL emissions, and the photocatalytic activity of the as-synthesized samples for the degradation process of Rhodamine B has been demonstrated. The surface structure and morphologies were characterized by field emission scanning electron microscopy. To complement and rationalize the experimental results, the geometry, electronic structures, and morphologies of as-synthesized samples were characterized by first-principles quantum-mechanical calculations at the density functional theory level. By using Wulff construction, based on the values of the surface energies for the (001), (100), (110), (111), (011) and (112) surfaces, a complete map of the available morphologies for PbMoO4 was obtained and a good agreement between the experimental and theoretical predicted morphologies was found. The structural and electronic changes induced by the substitution of Pb by Ca and Sr allow us to find a relationship among morphology, the electron-transfer process at the exposed surfaces, optical properties, and photocatalytic activity. We believe that our results offer new insights regarding the local coordination of superficial Pb/Ca/Sr and Mo cations (i.e., clusters) on each exposed surface of the corresponding morphology, which dictate the photocatalytic activities of the as-synthesized samples, a field that has so far remained unexplored. The present study, which combines multiple experimental methods and first-principles calculations, provides a deep understanding of the local structures, bonding, morphologies, band gaps, and electronic and optical properties, and opens the door to exploit the electrical, optical and photocatalytic activity of this very promising family of materials.

4.
Injury ; 51 Suppl 1: S74-S79, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32081396

RESUMO

Femoral shaft fractures present high morbidity and important complications and consequences, being spiral fractures the most complicated from a biomechanical point of view, being unstable and without possibility of getting a good contact between nail and femoral endosteum. Femoral diaphyseal fractures are treated, usually, by means of intramedullary nailing. So, it is necessary to know the osteosynthesis stability and which locking screws combination is optimal. This work studies the use of reamed locked intramedullary nails in spiral femoral fractures located along zones 2 and 4 of wiss, depending on the spire length, corresponding to 32-A spiral type in AO/OTA classification, which represent a percentage of 23% within the total of diaphyseal fractures. A three-dimensional finite element model of the femur was developed, modeling a spiral fracture with different spiral lengths and gaps. A femoral nail was used, considering two transversal screws both at the proximal and the distal parts. The study was focused on the immediately post-operative stage, verifying the appropriate stability of the osteosynthesis. Reamed intramedullary blocked nails provide appropriate stability of femoral spiral fractures, considering global mobility of femoral head with respect to femoral condyles, relative displacements between fragments at fracture site, stresses at nail and locking screws, and stresses at cortical bone. The obtained results show that the use of blocked reamed nails in spiral femoral fractures can be considered as an appropriate surgical technique, providing sufficient stability in order to obtain an adequate fracture healing.


Assuntos
Fraturas do Fêmur/cirurgia , Fixação Intramedular de Fraturas/instrumentação , Fixação Intramedular de Fraturas/métodos , Imageamento Tridimensional/métodos , Modelos Anatômicos , Fenômenos Biomecânicos , Pinos Ortopédicos , Fraturas do Fêmur/fisiopatologia , Análise de Elementos Finitos , Consolidação da Fratura , Humanos , Masculino , Pessoa de Meia-Idade , Estresse Mecânico , Resultado do Tratamento
5.
Injury ; 51 Suppl 1: S80-S88, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32067772

RESUMO

Supracondylar femoral fractures account for a noticeable percentage of the femoral shaft fractures, affecting two etiological groups: high energy trauma in young men, with good bone quality, and older women with osteoporotic femur. Surgical treatment of those kind of fractures remains controversial, with different surgical options such as plate and sliding barrel locking condylar plate, less invasive stabilization system (LISS) or intramedullary nailing, which has emerged as a new fixation choice in the treatment of that type of fractures. The present work performs a comparative study about the biomechanical behavior of anterograde and retrograde nailing in supracondylar femoral fractures type A, in order to determine the best choice of nailing and locking configuration. A three-dimensional finite element model of the femur was developed, modeling femoral supracondylar fracture and different nailing configurations, both for anterograde and retrograde nails. The study was focused on the immediately post-operative stage, verifying the appropriate stability of the osteosynthesis. The obtained results show a better biomechanical behavior for anterograde nails, providing a better stability from the point of view of global movements, lower stresses in screws, and less stress concentration in cortical bone. So, for the analyzed fractures and osteosyntheses types, anterograde nailing has demonstrated to be a better surgical option, being an excellent indication in supracondylar fractures of femur, with clear benefits compared to retrograde nailing, providing a better stabilization which enables for a more satisfactory fracture healing.


Assuntos
Fraturas do Fêmur/cirurgia , Fixação Intramedular de Fraturas/instrumentação , Fixação Intramedular de Fraturas/métodos , Imageamento Tridimensional/métodos , Modelos Anatômicos , Fenômenos Biomecânicos , Pinos Ortopédicos , Placas Ósseas , Fraturas do Fêmur/fisiopatologia , Análise de Elementos Finitos , Consolidação da Fratura , Humanos , Masculino , Pessoa de Meia-Idade , Estresse Mecânico , Resultado do Tratamento
6.
J Mech Behav Biomed Mater ; 102: 103507, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31877516

RESUMO

For colonic stents design, the interaction with colonic tissue is essential in order to characterize the appropriate radial stiffness which provides a minimum lumen for intestinal transit to be maintained. It is therefore important to develop suitable constitutive models allowing the mechanical behavior of the colon tissue to be characterized. The present work investigates the biomechanical behavior of colonic tissue by means of biaxial tests carried out on different parts of the colonic tract taken from several porcine specimens. Samples from the colonic tract were quasi-statically tensioned using a load-controlled protocol with different tension ratios between the circumferential and the axial directions. Fitting techniques were then used to adjust specific hyperelastic models accounting for the multilayered conformation of the colonic wall and the fiber-reinforced configuration of the corresponding tissues. It was found that the porcine colon changed from a more isotropic to a more anisotropic tissue and became progressively more flexible and compliant in circumferential direction depending on the position along the duct as it approaches the rectum. The best predictive capability of mechanical behavior corresponds to the Four Fiber Family model showing mean values of coefficient of determination R2=0.97, and a normalized root mean square error of εNRMS=0.0814 for proximal spiral samples, and R2=0.89 , ÎµNRMS=0.1600 and R2=0.94 , ÎµNRMS=0.1227 for distal spiral and descending colon samples, respectively. The other analyzed models provide good results for proximal spiral colon specimens, which have a lower degree of anisotropy. The analyzed models with the fitted elastic parameters can be used for more realistic and reliable FE simulations, providing the appropriate framework for the design of optimal devices for the treatment of colonic diseases.


Assuntos
Colo , Animais , Anisotropia , Fenômenos Biomecânicos , Simulação por Computador , Estresse Mecânico , Suínos , Resistência à Tração
7.
Inorg Chem ; 58(17): 11738-11750, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31415162

RESUMO

In2O3 and La3+-doped In2O3 nanostructures were synthesized through a facile and fast chemical route based on the microwave-assisted hydrothermal method combined with rapid thermal treatment in a microwave oven. The presence of the La3+ doping process modifies the size and morphology of the In2O3 nanostructures and also stabilizes the rhombohedral (rh) In2O3 phase with respect to the most stable cubic (bcc) polymorph. X-ray diffraction (XRD) patterns and Rietveld refinements, Raman, UV-vis, and energy dispersive X-ray (EDX) spectroscopies, transmission electron (TEM) and field-emission scanning electron (FE-SEM) microscopies, as well as PL emissions have been performed. To complement and rationalize the experimental results, first-principle calculations, based on density functional theory, are carried out to obtain the formation energies of the In2O3 and bcc- and rh-In2O3-doped phases, their geometry and electronic properties. Theoretical results are able to explain the relative stabilization of the rh-phase with respect to the bcc-phase based on the analysis geometry changes and the electronic redistribution induced by the La3+ doping process. In addition, Wulff construction is employed to match the theoretical and experimental morphologies of the cubic phase. The synthesized samples were applied for the O2 evolution reaction (OER). The La3+-doped In2O3 film presents superior electrocatalytic activity, with an onset potential lower than the undoped In2O3 film that can be associated with the increase in electron density caused by the La3+ doping process. This study provides a versatile strategy for obtaining In2O3 and La3+-doped In2O3 nanostructures for practical applications.

8.
Phys Chem Chem Phys ; 20(3): 1923-1937, 2018 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-29297523

RESUMO

The present joint experimental and theoretical work provides in-depth understanding on the morphology and structural, electronic, and optical properties of ZnWO4 nanocrystals. Monoclinic ZnWO4 nanocrystals were prepared at three different temperatures (140, 150, and 160 °C) by a microwave hydrothermal method. Then, the samples were investigated by X-ray diffraction with Rietveld refinement analysis, field-emission scanning electron microscopy, transmission electronic microscopy, micro-Raman and Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and photoluminescence measurements. First-principles theoretical calculations within the framework of density functional theory were employed to provide information at the atomic level. The band structure diagram, density of states, Raman and infrared spectra were calculated to understand the effect of structural order-disorder on the properties of ZnWO4. The effects of the synthesis temperature on the above properties were rationalized. The band structure revealed direct allowed transitions between the VB and CB and the experimental results in the ultraviolet-visible region were consistent with the theoretical results. Moreover, the surface calculations allowed the association of the surface energy stabilization with the temperature used in the synthesis of the ZnWO4 nanocrystals. The photoluminescence properties of the ZnWO4 nanocrystals prepared at 140, 150, and 160 °C were attributed to oxygen vacancies in the [WO6] and [ZnO6] clusters, causing a red shift of the spectra. The ZnWO4 nanocrystals obtained at 160 °C exhibited excellent photodegradation of Rhodamine under ultraviolet light irradiation, which was found to be related to the surface energy and the types of clusters formed on the surface of the catalyst.

9.
Equine Vet J ; 49(6): 767-769, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28502090

RESUMO

BACKGROUND: Lipid emulsion has been reported to be effective for the treatment of local anaesthetic overdoses in rats, dogs and man. OBJECTIVES: To describe the successful treatment of cardiovascular lidocaine toxicity in a foal with intravenous lipid administration. STUDY DESIGN: Observational study: case report. METHODS: An 8-month-old Arabian cross foal was anaesthetised for removal of the right alar fold and nasal plate. Anaesthesia was maintained with isoflurane in oxygen and lidocaine administered with a loading dose followed by a continuous rate infusion (CRI). The anaesthetic period was uneventful and 30 min before expected termination of the procedure lidocaine infusion was stopped. A sudden drop in mean arterial blood pressure was then observed. The ECG signal was lost, the end tidal CO2 tension dropped from 40 to 10 mmHg, corneal reflex was absent and asystole diagnosed. Cardiopulmonary resuscitation manoeuvres were immediately initiated, but epinephrine and atropine were unsuccessfully administered. Lipid emulsion was administered and the heart rate and arterial blood pressure gradually returned to normal. RESULTS: The foal recovered consciousness 3 h later, regained its sternal position, was responsive and 20 h later was able to stand up alone. MAIN LIMITATIONS: It will be necessary to evaluate a greater number of cases to determine the effectiveness of lipids in foals intoxicated with lidocaine. CONCLUSION: Intravenous lipid emulsion may be helpful in the treatment of potentially lethal cardiotoxicity attributable to lidocaine overdose in the foal.


Assuntos
Emulsões Gordurosas Intravenosas/uso terapêutico , Parada Cardíaca/veterinária , Doenças dos Cavalos/induzido quimicamente , Lidocaína/efeitos adversos , Administração Intravenosa , Animais , Parada Cardíaca/induzido quimicamente , Parada Cardíaca/tratamento farmacológico , Doenças dos Cavalos/tratamento farmacológico , Cavalos
10.
Actas dermo-sifiliogr. (Ed. impr.) ; 108(4): 346-353, mayo 2017. graf, tab
Artigo em Espanhol | IBECS | ID: ibc-163118

RESUMO

Introducción: La urticaria crónica espontánea es una enfermedad prevalente, de difícil manejo terapéutico y con una importante repercusión en la calidad de vida del paciente. Objetivo: Describir las características epidemiológicas, clínicas y la respuesta terapéutica de los pacientes con urticaria crónica espontánea actuando según la guía de consenso EAACI/GA(2)LEN/EDF/WAO. Material y método: Estudio descriptivo transversal que incluyó todos los pacientes con urticaria crónica espontánea visitados en una consulta específica de alergia cutánea de un servicio de dermatología de un hospital terciario en España desde julio de 2011 hasta julio de 2015. Resultados: Cien pacientes con urticaria crónica espontánea participaron en el estudio. El 43% asociaba una urticaria inducible. El 40% asociaba angioedema. El 53% de los pacientes tomaba antiinflamatorios no esteroideos en el momento del diagnóstico. Todos los pacientes fueron tratados con antihistamínicos-H1 de segunda generación, pero solo un 18% se controló con dosis licenciadas, mientras que el aumento hasta 4 veces la dosis logró controlar el 74% de los pacientes. Los pacientes con angioedema requirieron dosis mayores de antihistamínicos-H1 de segunda generación que los pacientes sin angioedema para el control de la urticaria crónica espontánea, siendo el angioedema un factor asociado a falta de respuesta a tratamiento con antihistamínicos-H1 de segunda generación (OR 6,1%, p < 0,001). Uno de cada 4 pacientes no respondió a antihistamínicos-H1 de segunda generación y requirió omalizumab o ciclosporina para su control. Conclusiones: El control de la urticaria crónica espontánea precisa de la utilización de antihistamínicos-H1 de segunda generación a dosis más altas de las licenciadas en la mayoría de los casos. El angioedema se asocia a falta de respuesta al tratamiento con antihistamínicos. El omalizumab y la ciclosporina logran controlar los casos refractarios. La evitación de antiinflamatorios no esteroideos no es una práctica habitual en los pacientes con urticaria crónica espontánea (AU)


Introduction: Chronic spontaneous urticaria is a prevalent and difficult-to-treat condition that has a very negative impact on patient quality of life. Objective: To describe the epidemiological and clinical characteristics of patients presenting with chronic spontaneous urticaria and the response to treatment administered according to the EAACI/GA(2)LEN/EDF/WAO consensus guideline. Material and method: Descriptive cross-sectional study of all the patients with chronic spontaneous urticaria who consulted a skin allergy unit in the dermatology department of a tertiary hospital in Spain between July 2011 and July 2015. Results: The study included 100 patients with chronic spontaneous urticaria; inducible urticaria was present in 43% of cases, and angioedema in 40%. On diagnosis, 53% of patients were taking nonsteroidal anti-inflammatory drugs. All patients were treated with second generation H1-antihistamines, but the standard dose was sufficient in only 18% of cases. Higher doses (up to 4 times the standard dose) achieved control of the urticaria in 74% of the patients studied. Higher doses of second generation H1-antihistamines were required to control the condition in patients with angioedema, and the presence of angioedema was associated with a lack of response to treatment with these drugs (OR, 6.1%; P < .001). One in 4 patients failed to respond to second generation H1-antihistamines and required treatment with omalizumab or ciclosporin to control their condition. Conclusions: Doses of H1-antihistamines higher than the standard dose are required in most cases to achieve control of chronic spontaneous urticaria. Angioedema is associated with failure to respond to treatment with antihistamines. In refractory cases, control of the condition can be achieved with omalizumab or ciclosporin. Patients with chronic spontaneous urticaria do not generally avoid the use of nonsteroidal anti-inflammatory agents (AU)


Assuntos
Humanos , Urticária/epidemiologia , Hipersensibilidade/epidemiologia , Antagonistas dos Receptores Histamínicos/uso terapêutico , Corticosteroides/uso terapêutico , Doença Crônica , Qualidade de Vida , Hipersensibilidade Imediata/epidemiologia , Comorbidade , Padrões de Prática Médica , Anti-Inflamatórios não Esteroides/efeitos adversos
11.
J Mech Behav Biomed Mater ; 71: 250-261, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28365542

RESUMO

The choice of necessary stent properties depends mainly on the length of the stenosis and degree of occlusion. So a stent design with variable radial stiffness along its longitudinal axis would be a good option. The design proposed corresponds to a tube-based stent with closed diamond-shaped cells made from a NiTi alloy. By acting independently on different geometric factors, variable geometries can be obtained with different radial force reactions. A design adjustment according to specific requirements, in order to get a better fit to ill-duct and reduces complications, is possible. A parametric analysis using finite element has been conducted to determine the influence of slot length, number of circumferential slots, tube thickness and shape-factor on stent mechanical behavior, which allow eliminating the need for extensive experimental work and knowing and quantifying the influence of those factors. The results of finite element simulations have been used, by means of least-squares fit techniques, to obtain analytical expressions for the main mechanical characteristics of the stent (Chronic Expansive Radial Force and Radial Compression Resistance) in terms of the different geometrical factors. This allows the stent geometry to be customized without launching an iterative and costly process of modeling and simulation for each case.


Assuntos
Desenho de Prótese , Stents , Constrição Patológica , Análise de Elementos Finitos , Fenômenos Mecânicos
12.
Actas Dermosifiliogr ; 108(4): 346-353, 2017 May.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-28219634

RESUMO

INTRODUCTION: Chronic spontaneous urticaria is a prevalent and difficult-to-treat condition that has a very negative impact on patient quality of life. OBJECTIVE: To describe the epidemiological and clinical characteristics of patients presenting with chronic spontaneous urticaria and the response to treatment administered according to the EAACI/GA(2)LEN/EDF/WAO consensus guideline. MATERIAL AND METHOD: Descriptive cross-sectional study of all the patients with chronic spontaneous urticaria who consulted a skin allergy unit in the dermatology department of a tertiary hospital in Spain between July 2011 and July 2015. RESULTS: The study included 100 patients with chronic spontaneous urticaria; inducible urticaria was present in 43% of cases, and angioedema in 40%. On diagnosis, 53% of patients were taking nonsteroidal anti-inflammatory drugs. All patients were treated with second generation H1-antihistamines, but the standard dose was sufficient in only 18% of cases. Higher doses (up to 4 times the standard dose) achieved control of the urticaria in 74% of the patients studied. Higher doses of second generation H1-antihistamines were required to control the condition in patients with angioedema, and the presence of angioedema was associated with a lack of response to treatment with these drugs (OR, 6.1%; P<.001). One in 4 patients failed to respond to second generation H1-antihistamines and required treatment with omalizumab or ciclosporin to control their condition. CONCLUSIONS: Doses of H1-antihistamines higher than the standard dose are required in most cases to achieve control of chronic spontaneous urticaria. Angioedema is associated with failure to respond to treatment with antihistamines. In refractory cases, control of the condition can be achieved with omalizumab or ciclosporin. Patients with chronic spontaneous urticaria do not generally avoid the use of nonsteroidal anti-inflammatory agents.


Assuntos
Guias de Prática Clínica como Assunto , Urticária/tratamento farmacológico , Corticosteroides/uso terapêutico , Angioedema/complicações , Angioedema/tratamento farmacológico , Anti-Inflamatórios não Esteroides/uso terapêutico , Doenças Autoimunes/epidemiologia , Doença Crônica , Comorbidade , Estudos Transversais , Ciclosporina/uso terapêutico , Dermatologia/métodos , Gerenciamento Clínico , Quimioterapia Combinada , Hepatite Viral Humana/epidemiologia , Antagonistas dos Receptores Histamínicos H1/uso terapêutico , Humanos , Antagonistas de Leucotrienos/uso terapêutico , Omalizumab/uso terapêutico , Fatores de Risco , Centros de Atenção Terciária , Urticária/complicações , Urticária/epidemiologia
13.
Radiology ; 282(2): 569-575, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27626676

RESUMO

Purpose To develop a method to create anthropomorphic phantoms of individual patients with high precision of anatomic details and radiation attenuation properties. Materials and Methods Inkjet cartridges were filled with potassium iodide solutions (600 mg/mL) and prints were realized on plain paper (80 g/m2). Stacks of 100 prints resulted in three-dimensional phantoms of 1 cm thickness. In a first step, reproduction of patient anatomy was tested by printing computed tomographic (CT) images of a real patient abdomen scan. In a second step, gray scales, iodine deposition, and Hounsfield units were investigated by printing geometric phantoms with gray scales ranging from 0% (white) to 100% (black). On the basis of these results, a gray-scale-correction procedure was developed to achieve realistic Hounsfield units in the patient phantom. In a third step, reproduction of the real patient's Hounsfield units was verified by printing the initial patient CT scan again after application of the gray-scale-correction procedure. Data were analyzed by using Pearson correlation, linear regression, and nonlinear regression. Results The first abdomen phantom showed a detailed reproduction of the patient anatomy and demonstrated feasibility of the concept. However, individual-organ Hounsfield units deviated from the real patient CT scan. Analysis of the geometric phantoms revealed an exponential correlation between template gray scales and printer deposition. Application of a correction procedure to the template gray scales allowed for a linear correlation (r = 0.9946; 95% confidence interval: 0.9916, 0.9966). After the same correction procedure was applied to the abdomen phantom, linear correlation of phantom and patient Hounsfield units was confirmed (r = 0.9925; 95% confidence interval: 0.9635, 0.9985). Conclusion The method presented in this work can realize realistic and customizable phantoms for diagnostic and therapeutic radiology, including the reproduction of individual patients. © RSNA, 2016.


Assuntos
Imagens de Fantasmas , Impressão Tridimensional , Tomografia Computadorizada por Raios X , Desenho de Equipamento , Estudos de Viabilidade , Humanos
14.
Rev. esp. patol. torac ; 28(5): 242-247, dic. 2016. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-159713

RESUMO

OBJETIVO: Determinar, en pacientes con enfermedad pulmonar obstructiva crónica (EPOC) las variables que en la prueba de 6 minutos marcha (P6MM) aportan información sobre el grado de desaturación nocturna. METODOLOGÍA: Estudio prospectivo, transversal con muestreo consecutivo. Se incluyeron sujetos ambulatorios, en estabilidad clínica, con una saturación periférica de oxígeno (SapO2 ≥92%) y sin contraindicación para realizar una P6MM. A todos los sujetos se les realizaron dos determinaciones con el mismo pulsioxímetro (Pulsox-300i) durante la P6MM y sueño. Se realizó correlación entre las variables de la P6MM y el porcentaje del tiempo nocturno con SapO2 <90% (T90) y se construyó un modelo de regresión para evaluar la variabilidad del T90. RESULTADOS: Fueron incluidos 47 enfermos, 37 hombres (79%), edad = 61,6 ± 7,5 años, y un FEV1 post-BD = 50 ± 18,3 %. Respecto al T90 nocturno, las variables que mostraron correlación significativa en la P6MM fueron la SapO2 , basal, media y mínima, y el T90 y T88 (SapO2 <88%). El modelo de regresión lineal mostró una R2 ajustada de 0,644; (p <0,001) siendo las variables que se asociaron de forma independiente al T90 nocturno: el IMC (p = 0,049), SapO2 basal (p = 0,001), SapO2 media-P6MM (p = 0,006) y el T88-P6MM (p = 0,048). CONCLUSIONES: La P6MM aporta información relevante sobre el grado de desaturación nocturna. La SapO2 basal, y la SapO2 media y el valor del T88 fueron las variables que en la P6MM mostraron mayor influencia sobre la variabilidad del T90 nocturno


OBJECTIVE: Determine in patients with chronic obstructive pulmonary disease (COPD) those variables that provide information about degree of nocturnal desaturation in the 6-minute walk test (6MWT). METHODS: Prospective, transversal study with consecutive sampling. Outpatients were included in clinical stability, with peripheral oxygen saturation (SapO2 ≥92%) and without contraindication for a 6MWT. In all subjects were performed two determinations with the same pulse oximeter (Pulsox-300i) during the 6MWT and sleep. Was performed correlation between variables 6MWT and percentage nigh time with SapO2<90% (T90) and a regression model were constructed to evaluate the variability of the T90. RESULTS: We included 47 patients, 37 men (79%), age = 61.6 ± 7.5 years, and post-BD FEV1 = 50 ± 18.3%. Regard to T90 nocturnal, the variables that showed significant correlation in 6MWT were SapO2 basal, mean and minimum, and T90 and T88 (SapO2 <88%). The linear regression model showed an adjusted R2 of 0.644 (p< 0.001), and BMI (p = 0.049), baseline SapO2 6MWT (p = 0.001), mean SapO2 (p = 0.006) and T88-6MWT (p = 0.048) were the only variables independently associated to nocturnal T90. CONCLUSIONS: The 6MWT provides relevant information on the level of nocturnal desaturation. The basal SapO2 and mean and the value of T88 were the 6MWT variables that showed the greatest influence on variability nocturnal T90


Assuntos
Humanos , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Hipóxia/epidemiologia , Teste de Esforço/estatística & dados numéricos , Oximetria/estatística & dados numéricos , Caminhada/fisiologia , Tolerância ao Exercício/fisiologia
15.
Neurología (Barc., Ed. impr.) ; 31(9): 606-612, nov.-dic. 2016. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-158305

RESUMO

Introducción: Pensamos que en la última década ha existido un aumento en la demanda de atención de neurología pediátrica (NP) por parte de la población pero también con un cambio cualitativo en las patologías que se atienden. Por este motivo planteamos realizar un segundo registro (2013) y analizar si existían o no diferencias con el efectuado en el año 2002. Métodos: Se realiza un registro prospectivo de actividad asistencia de NP en el Hospital Universitario de Getafe en 2013 y se compara con otro registro prospectivo previo realizado en 2002. Resultados: Se ha pasado de 1.300 consultas a 1.982 (incremento del 52,46%) y de 32,6 consultas/1.000 niños al año a 57,48 (76,32% de aumento). La actividad en consulta supone el 92,2% de toda la asistencia neuropediátrica del 2013; actualmente el trastorno por déficit de atención e hiperactividad (TDAH) es la patología más frecuente (27,6% en 2013/8,1% en 2002). Aunque las cefaleas siguen siendo muy frecuentes han disminuido (19% en 2013/22% en 2002). Como primeras consultas la cefalea sigue siendo la más frecuente en 2013 (32,1%), seguida del TDAH (19,1%). En régimen de hospitalización la epilepsia continúa siendo el diagnóstico más frecuente (30,3% en 2013/36,7% en 2002). Conclusiones: La NP continúa siendo una actividad básicamente ambulatoria, con un incremento considerable en los últimos años. Este aumento se debe fundamentalmente a los trastornos del neurodesarrollo y muy especialmente al TDAH. Podríamos decir que el TDAH es a la NP lo que la demencia a la neurología general


Introduction: We believe that the demand for paediatric neurology (PN) care has increased over the past decade, and that reasons for requesting consultations have also changed. The objective of this study is to complete a registry study to profile the demand for PN care in 2013 and compare results to those from a study performed in 2002. Methods: A prospective registry of PN healthcare activities was completed at Hospital Universitario de Getafe in 2013. Results were compared with those from a prospective registry study conducted in 2002. Results: The number of visits increased from 1,300 in 2002 to 1,982 in 2013 (a 52.46% increase), and from 32.6 visits per 1,000 children to 57.48 (a 76.32% increase). Outpatient consultations accounted for 92.2% of all PN consultations in 2013. Currently, attention deficit-hyperactivity disorder (ADHD) is the most frequent diagnosis (27.6% in 2013 vs. 8.1% in 2002). Although the percentage of headache consultations has decreased (19% in 2013 vs. 22% in 2002), headache was still the most common reason for an initial visit in 2013 (32.1%), followed by ADHD (19.1%). Epilepsy remains the most frequent diagnosis in hospitalised patients (30.3% in 2013 vs. 36.7% in 2002). Conclusions: PN is fundamentally an outpatient activity that has increased considerably in recent years. This increase is mainly due to neurodevelopmental disorders, especially ADHD. We might state that the role of ADHD in PN is comparable to that of dementia in general neurology


Assuntos
Humanos , Masculino , Feminino , Criança , Doenças do Sistema Nervoso/epidemiologia , Doenças do Sistema Nervoso/prevenção & controle , Transtorno do Deficit de Atenção com Hiperatividade/complicações , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Epilepsia/complicações , Epilepsia/diagnóstico , Neurologia/métodos , Estudos Prospectivos , Administração Sanitária/métodos , Administração Sanitária/tendências
16.
Comput Methods Programs Biomed ; 131: 37-50, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27265047

RESUMO

Osteoporotic vertebral fractures represent a major cause of disability, loss of quality of life and even mortality among the elderly population. Decisions on drug therapy are based on the assessment of risk factors for fracture from bone mineral density (BMD) measurements. A previously developed model, based on the Damage and Fracture Mechanics, was applied for the evaluation of the mechanical magnitudes involved in the fracture process from clinical BMD measurements. BMD evolution in untreated patients and in patients with seven different treatments was analyzed from clinical studies in order to compare the variation in the risk of fracture. The predictive model was applied in a finite element simulation of the whole lumbar spine, obtaining detailed maps of damage and fracture probability, identifying high-risk local zones at vertebral body. For every vertebra, strontium ranelate exhibits the highest decrease, whereas minimum decrease is achieved with oral ibandronate. All the treatments manifest similar trends for every vertebra. Conversely, for the natural BMD evolution, as bone stiffness decreases, the mechanical damage and fracture probability show a significant increase (as it occurs in the natural history of BMD). Vertebral walls and external areas of vertebral end plates are the zones at greatest risk, in coincidence with the typical locations of osteoporotic fractures, characterized by a vertebral crushing due to the collapse of vertebral walls. This methodology could be applied for an individual patient, in order to obtain the trends corresponding to different treatments, in identifying at-risk individuals in early stages of osteoporosis and might be helpful for treatment decisions.


Assuntos
Vértebras Lombares/lesões , Osteoporose/tratamento farmacológico , Fraturas por Osteoporose/epidemiologia , Probabilidade , Fraturas da Coluna Vertebral/epidemiologia , Densidade Óssea , Conservadores da Densidade Óssea/uso terapêutico , Humanos
17.
Talanta ; 146: 815-22, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26695334

RESUMO

Ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with electrospray ionization has been proposed for the determination of fifteen natural destruxins (A, B, C, D, E, Ed, Ed1, A2, B2, D2, E2, Cl, DesmA, DesmB, and DH-A), secondary metabolites with insecticidal and phytotoxic activities produced by Metarhizium species fungus, which are being studied as biological agents in pest control. Therefore, procedures to control them in the food chain are required, starting with crops. As a consequence, in this study, a simple QuEChERS-based destruxin (dtx) extraction procedure has been developed and validated in four different parts of potato plant (tuber, root, stem and leaves) for the first time. For dtx A, the limits of detection obtained, ranged between 0.5 and 1.3 µg/kg, and for quantification, ranged between 1.7 and 4.2 µg/kg. Precision values were below 8.5%; and in all cases, recoveries were higher than 91%. Finally, the method has been applied in potato samples inoculated by EAMa 01/58-Su strain, where dtxs A and B were detected and quantified. In all cases, dtx B concentration was higher than dtx A.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Depsipeptídeos/isolamento & purificação , Solanum tuberosum/química , Espectrometria de Massas em Tandem/métodos , Calibragem , Metarhizium/fisiologia , Reprodutibilidade dos Testes , Solanum tuberosum/microbiologia , Fatores de Tempo
18.
Neurologia ; 31(9): 606-612, 2016.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-25529177

RESUMO

INTRODUCTION: We believe that the demand for paediatric neurology (PN) care has increased over the past decade, and that reasons for requesting consultations have also changed. The objective of this study is to complete a registry study to profile the demand for PN care in 2013 and compare results to those from a study performed in 2002. METHODS: A prospective registry of PN healthcare activities was completed at Hospital Universitario de Getafe in 2013. Results were compared with those from a prospective registry study conducted in 2002. RESULTS: The number of visits increased from 1,300 in 2002 to 1,982 in 2013 (a 52.46% increase), and from 32.6 visits per 1,000 children to 57.48 (a 76.32% increase). Outpatient consultations accounted for 92.2% of all PN consultations in 2013. Currently, attention deficit-hyperactivity disorder (ADHD) is the most frequent diagnosis (27.6% in 2013 vs. 8.1% in 2002). Although the percentage of headache consultations has decreased (19% in 2013 vs. 22% in 2002), headache was still the most common reason for an initial visit in 2013 (32.1%), followed by ADHD (19.1%). Epilepsy remains the most frequent diagnosis in hospitalised patients (30.3% in 2013 vs. 36.7% in 2002). CONCLUSIONS: PN is fundamentally an outpatient activity that has increased considerably in recent years. This increase is mainly due to neurodevelopmental disorders, especially ADHD. We might state that the role of ADHD in PN is comparable to that of dementia in general neurology.


Assuntos
Necessidades e Demandas de Serviços de Saúde , Neurologia , Pediatria , Atenção Primária à Saúde/estatística & dados numéricos , Adolescente , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Criança , Pré-Escolar , Atenção à Saúde , Epilepsia/diagnóstico , Feminino , Cefaleia/diagnóstico , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Prospectivos , Encaminhamento e Consulta/estatística & dados numéricos , Sistema de Registros
19.
Dalton Trans ; 45(3): 1185-91, 2016 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-26661688

RESUMO

Metastable silver tungstate (ß-Ag2WO4) has attracted much attention lately because of its many potential applications. However, the synthesis of metastable phases of inorganic compounds is challenging because of the ease of transformation to the stable phase. We have overcome this challenge and have successfully synthesized ß-Ag2WO4 microcrystals using a dropwise precipitation (DP) method in aqueous media at low temperature. The microcrystals were characterized by X-ray diffraction (XRD), including powder X-ray diffraction structural determination, field-emission scanning electron microscopy (FE-SEM), and micro-Raman/ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. To complement the experimental data, we present first-principles quantum-mechanical density functional theory (DFT) calculations. Using XRD data, Raman/UV-vis data, and the determined optical band gap, together with geometric optimization calculations, we confirmed the structure of this compound. ß-Ag2WO4 has a hexagonal structure with a P63/m space group. The building blocks of the lattice comprise two types of W-O clusters, [WO4] and [WO5], coordinated to four and five O atoms, respectively, and two types of Ag-O clusters, [AgO6], and [AgO5], linked to six and five O atoms, respectively. This type of fundamental study, combining multiple experimental methods and first-principles calculations, helps to obtain a basic understanding of the local structure and bonding in the material.

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