RESUMEN
The exploitation of both conventional and unconventional hydrocarbons may lead to still not well-known environmental consequences such as ground deformation and induced/triggered seismicity. Identifying and characterizing these effects is fundamental for prevention or mitigation purposes, especially when they impact populated areas. Two case studies of such effects on hydrocarbon-producing basins in Argentina, the Neuquén and the Golfo de San Jorge, are presented in this work. The intense hydrocarbon production activities in recent years and their potential link with the occurrence of two earthquakes of magnitude 4.9 and 5 near the operating well fields is assessed. A joint analysis of satellite radar interferometry and records of fluid injection and extraction demonstrate that, between 2017 and 2020, vertical ground displacements occurred in both study areas over active well fields that might indicate a correlation to hydrocarbon production activities. Coseismic deformation models of the two earthquakes constrain source depths to less than 2 km. The absence of seismicity before the beginning of the hydrocarbon activities in both areas, and the occurrence of the two largest and shallow earthquakes in the vicinity of the active well fields just after intensive production periods, points towards the potential association between both phenomena.
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Terremotos , Argentina , Hidrocarburos , Radar , InterferometríaRESUMEN
An in-line digital optical sensor was proposed. It was built from a tapered depressed-cladding single-mode fiber and modeled as a coaxial Mach-Zehnder interferometer. The principle of operation of the optical digital sensor is based on the computation of the number of optical power transfer turning points (PTTP) from the transmission data of the component. Biconic tapers with high values of PTTP, high spectral resolution, high extinction ratio, and low insertion loss were modeled, fabricated, and characterized. As a proof of concept, an in-line digital strain sensor was fabricated and characterized. It presents a free spectral range of 1.3 nm, and produced 96 PTTP, at λ0 = 1.55 µm, under stretch of ΔL = 707 µm, therefore producing a digital resolution of 7.4 µm/PTTP. The sensor also produced a quasi-symmetric response to stretch and compression.
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Interferometría , Fibras ÓpticasRESUMEN
An optical strain gauge based on a balloon-like interferometer structure formed by a bent standard single-mode fiber combined with a 3D printer piece has been presented and demonstrated, which can be used to measure displacement. The interferometer has a simple and compact size, easy fabrication, low cost, and is repeatable. The sensor is based on the interference between the core and cladding modes. This is caused by the fiber's curvature because when light propagates through the curved balloon-shaped interferometer region, a portion of it will be released from the core limitation and coupled to the cladding. The balloon has an axial displacement as a result of how the artwork was constructed. The sensor head is sandwiched between two cantilevers such that when there is a displacement, the dimension associated with the micro bend is altered. The sensor response as a function of displacement can be determined using wavelength shift or intensity change interrogation techniques. Therefore, this optical strain gauge is a good option for applications where structure displacement needs to be examined. The sensor presents a sensitivity of 55.014 nm for displacement measurements ranging from 0 to 10 mm and a strain sensitivity of 500.13 pm/µÏµ.
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Tecnología de Fibra Óptica , Interferometría , Diseño de Equipo , Interferometría/métodos , Fibras Ópticas , Refractometría/métodosRESUMEN
In many areas, the analysis of a cylindrical structure is necessary, and a form to analyze it is by evaluating the diameter changes. Some areas can be cited: pipelines for oil or gas distribution and radial growth of trees whose diameter changes are directly related to irrigation and the radial expansion since it depends on the water soil deficit. For some species, these radial variations can change in around 5 mm. This paper proposes and experimentally investigates a sensor based on a core diameter mismatch technique for diameter changes measurement. The sensor structure is a combination of a cylindrical piece developed using a 3D printer and a Mach-Zehnder interferometer. The pieces were developed to assist in monitoring the diameter variation. It is formed by splicing an uncoated short section of MMF (Multimode Fiber) between two standard SMFs (Singlemode Fibers) called SMF-MMF-SMF (SMS), where the MMF length is 15 mm. The work is divided into two main parts. Firstly, the sensor was fixed at two points on the first developed piece, and the diameter reduction caused dips or peaks shift of the transmittance spectrum due to curvature and strain influence. The fixation point (FP) distances used are: 5 mm, 10 mm, and 15 mm. Finally, the setup with the best sensitivity was chosen, from first results, to develop another test with an optimization. This optimization is performed in the printed piece where two supports are created so that only the strain influences the sensor. The results showed good sensitivity, reasonable dynamic range, and easy setup reproduction. Therefore, the sensor could be used for diameter variation measurement for proposed applications.
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Tecnología de Fibra Óptica , Interferometría , Diseño de Equipo , Interferometría/métodos , Fibras Ópticas , AguaRESUMEN
PURPOSE: To assess the axial length (AL) measurement failure rate using partial-coherence interferometry (PCI) and swept-source optical coherence tomography (SS-OCT) in dense cataracts. As a secondary outcome, the SS-OCT biometry was compared to immersion ultrasound. METHODS: This is a prospective cross-sectional and comparative study. Seventy eyes from 70 patients with dense cataracts were enrolled in this study. Dense cataract was defined according to the Lens Opacities Classification System III (LOCS III) scores equal to or more than NO4, NC4, C4, and P3. The failure rate of AL measurement was evaluated using PCI and SS-OCT. Anterior chamber depth (ACD), lens thickness (LT), and AL measurements obtained by SS-OCT were compared with IUS. RESULTS: AL measurement failure rate with PCI was 68.57% and 21.43% with SS-OCT (P = 0.007). AL measurement was achieved in 69.23% of NO4, 66.6% of P3, and 15.3% of mixed cataracts using PCI, while SS-OCT was achieved in 100% of NO4, NO5, P3, and P5 and 76.9% of mixed cataracts. Cortical cataracts alone did not influence AL measurement. Biometric data of ACD, LT, and AL were statistically different comparing US and SS-OCT with a good correlation of AL. CONCLUSION: SS-OCT significantly improves the rate of successful AL measurements when compared to PCI in dense cataracts. The LOCS III clinical cut-off for the use of SS-OCT ocular biometry may well be up to P4 and NO5.
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Catarata , Tomografía de Coherencia Óptica , Cámara Anterior , Longitud Axial del Ojo/diagnóstico por imagen , Biometría , Catarata/diagnóstico , Estudios Transversales , Humanos , Inmersión , Interferometría , Estudios Prospectivos , Reproducibilidad de los ResultadosRESUMEN
PURPOSE: To assess the agreement on biometric data obtained using the Verion image-guided surgery system and the swept-source-OCT biometer IOL Master 700. MATERIALS AND METHODS: All patients underwent biometry using the SS-OCT and the Image-Guide System. The comparison between instruments was assessed using the Intraclass correlation coefficient (ICC). Level of Agreement (LoA) employing the Bland-Altman analysis. RESULTS: The image-based system produced significantly higher keratometry values, evidencing a low LoA between the SS-OCT and the image-based system, ranging from -1.30 D to 0.65 D (1.95 D), -1.04 D to 0.72 D (1.76 D), and -1.31 D to 0.65 D (1.96 D), respectively. The LoA for the Cylinder ranged from -0.46 D to 0.74 D (1.2 D) and from 0.82 to 0.94 mm for WTW. CONCLUSIONS: In our study, the SS-OCT biometer and the Image-based System evidenced statistically significant differences in measuring the main biometric parameters except for the WTW.
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Catarata , Tomografía de Coherencia Óptica , Longitud Axial del Ojo/anatomía & histología , Biometría/métodos , Humanos , Interferometría/métodos , Reproducibilidad de los Resultados , Tomografía de Coherencia Óptica/métodosRESUMEN
The spike protein is the main protein component of the SARS-CoV-2 virion surface. The spike receptor-binding motif mediates recognition of the human angiotensin-converting enzyme 2 receptor, a critical step in infection, and is the preferential target for spike-neutralizing antibodies. Posttranslational modifications of the spike receptor-binding motif have been shown to modulate viral infectivity and host immune response, but these modifications are still being explored. Here we studied asparagine deamidation of the spike protein, a spontaneous event that leads to the appearance of aspartic and isoaspartic residues, which affect both the protein backbone and its charge. We used computational prediction and biochemical experiments to identify five deamidation hotspots in the SARS-CoV-2 spike protein. Asparagine residues 481 and 501 in the receptor-binding motif deamidate with a half-life of 16.5 and 123 days at 37 °C, respectively. Deamidation is significantly slowed at 4 °C, indicating a strong dependence of spike protein molecular aging on environmental conditions. Deamidation of the spike receptor-binding motif decreases the equilibrium constant for binding to the human angiotensin-converting enzyme 2 receptor more than 3.5-fold, yet its high conservation pattern suggests some positive effect on viral fitness. We propose a model for deamidation of the full SARS-CoV-2 virion illustrating how deamidation of the spike receptor-binding motif could lead to the accumulation on the virion surface of a nonnegligible chemically diverse spike population in a timescale of days. Our findings provide a potential mechanism for molecular aging of the spike protein with significant consequences for understanding virus infectivity and vaccine development.
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SARS-CoV-2/metabolismo , Glicoproteína de la Espiga del Coronavirus/metabolismo , Secuencias de Aminoácidos , Enzima Convertidora de Angiotensina 2/química , Enzima Convertidora de Angiotensina 2/genética , Enzima Convertidora de Angiotensina 2/metabolismo , COVID-19/patología , COVID-19/virología , Humanos , Concentración de Iones de Hidrógeno , Interferometría , Cinética , Unión Proteica , Dominios Proteicos , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , SARS-CoV-2/aislamiento & purificación , Alineación de Secuencia , Glicoproteína de la Espiga del Coronavirus/químicaRESUMEN
El implante de una lente intraocular fáquica puede resultar una opción lógica para los pacientes sumamente miopes que buscan liberarse de las gafas y de los lentes de contacto. Esta es una alternativa para corregir los grados de miopía extremos, y se diseñaron para permanecer dentro del ojo por muchos años. Con el cursar del tiempo, fisiológicamente comienza a opacarse el cristalino. Ante la necesidad de removerlo y de calcular una lente de potencia adecuada para el saco capsular y así conseguir la emetropía, surge un nuevo reto. El cálculo inexacto de la potencia dióptrica de la lente a implantar en la intervención quirúrgica es un problema y con él aparece la sorpresa refractiva; de ahí el objetivo de presentar con este caso la causa más frecuente de sorpresa refractiva tras la cirugía de catarata en un paciente miope con lente fáquica implantada. Se destaca la importancia de la longitud axil, sobre todo si esta se modifica después del implante de la lente fáquica para el correcto cálculo de la lente a implantar, así como el método ideal para su obtención: la interferometría óptica, sin olvidar la historia clínica previa al implante de la lente fáquica(AU)
Phakic intraocular lens implantation may be a logical option for extremely myopic patients who wish to get rid of their eyeglasses and contact lenses. This alternative was developed to correct extremely high degrees of myopia and remain inside the eye for many years. However, with the passing of time and due to physiological processes, the crystalline lens tends to become opaque. A new challenge is posed by the need to remove it and select a lens with an optical power appropriate to the capsular sac, thus achieving emmetropia. Inaccurate calculation of the dioptric power of the lens to be implanted in the surgical intervention is a problem leading to refractive surprise. Hence the interest in presenting a case illustrating the most common cause of refractive surprise after cataract surgery in a myopic patient with a phakic lens implant. The importance of axial length is highlighted, particularly whether it is modified after phakic lens implantation for accurate calculation of the lens to be implanted and the ideal method to obtain it: optical interferometry, without disregarding the medical record data preceding the phakic lens implantation(AU)
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Humanos , Femenino , Persona de Mediana Edad , Procedimientos Quirúrgicos Operativos/métodos , Extracción de Catarata/métodos , Lentes Intraoculares Fáquicas/efectos adversos , Interferometría/métodos , Registros Médicos , Miopía/etiologíaRESUMEN
In this paper, we propose a highly sensitive temperature sensor based on two cascaded Mach-Zehnder interferometers (MZIs) that work using the Vernier effect. The all-fiber MZIs were assembled by splicing a segment of capillary hollow-core fiber (CHCF) between two sections of multimode fibers (MMFs). This cascaded configuration exhibits a temperature sensitivity of 1.964 nm/°C in a range from 10 to 70 °C, which is ~67.03 times higher than the sensitivity of the single MZI. Moreover, this device exhibits a high-temperature resolution of 0.0153 °C. A numerical analysis was carried out to estimate the devices' temperature sensitivity and calculate the magnification of the sensitivity produced by the Vernier effect. The numerical results have an excellent agreement with the experimental results and provide a better insight into the working principle of the MZI devices. The sensor's performance, small size, and easy fabrication make us believe that it is an attractive candidate for temperature measurement in biological applications.
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Interferometría , Refractometría , Calor , TemperaturaRESUMEN
Objetivo: Testar a hipótese nula de que a orientação das ranhuras superficiais não influencia na vida em fadiga de fios de níquel-titânio (NiTi). Material e Métodos: Segmentos de fio de NiTi (Moreli, Sorocaba/SP, Brasil) medindo 30mm e com diâmetro de 0,40mm foram utilizados. As ranhuras foram criadas em relação à direção longitudinal, em 45 e 90 graus. O fio foi analisado sob microscopia eletrônica de varredura e a rugosidade, quantificada por interferometria. O número de ciclos para a fratura (NCF) foi determinado pelo teste de flexão rotativa. Resultados: A rugosidade entre os grupos de 45 e 90 graus apresentou diferenças estatisticamente significativas (p<0,05). O grupo sem ranhuras apresentou o maior NCF (p<0,05). O grupo com ranhuras em 45 graus apresentou maior NCF, em comparação ao grupo com 90 graus (p<0,05). Conclusões: A direção das ranhuras possui influência na vida em fadiga dos fios de NiTi. O NCF aumenta com a redução do ângulo das ranhuras em relação ao longo eixo do fio, independentemente da profundidade das ranhuras (AU).
Objective: this study tested the null hypothesis that the surface grooves orientation does not influence the NiTi wire cyclic fatigue. Material and methods: Segments of NiTi wire (Moreli, Sorocaba, Brazil) measuring 30mm and with a 0.40mm of diameter were used. Grooves were created in the longitudinal direction, at 45 degrees and 90 degrees. The wire was analyzed with SEM and the roughness was quantified by interferometry. The number of cycles until fracture (NCF) was determined by the cyclic fatigue test. Results: the roughness between 45 and 90 degrees groups presented differences (p<0.05). The group without grooves presented the highest NCF (p<0.05). The group with 45 degrees grooves presented better NCF in comparison to the group with 90 degrees (p<0.05). Conclusions: the direction of the grooves influences the fatigue life. The NCF increases with the reduction of the angle of the grooves in relation to the long axis, regardless of the depth of the grooves (AU).
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Humanos , Microscopía Electrónica de Rastreo , Aleaciones Dentales , Fatiga , InterferometríaRESUMEN
Vital signs not only reflect essential functions of the human body but also symptoms of a more serious problem within the anatomy; they are well used for physical monitoring, caloric expenditure, and performance before a possible symptom of a massive failure-a great variety of possibilities that together form a first line of basic diagnosis and follow-up on the health and general condition of a person. This review includes a brief theory about fiber optic sensors' operation and summarizes many research works carried out with them in which their operation and effectiveness are promoted to register some vital sign(s) as a possibility for their use in the medical, health care, and life support fields. The review presents methods and techniques to improve sensitivity in monitoring vital signs, such as the use of doping agents or coatings for optical fiber (OF) that provide stability and resistance to the external factors from which they must be protected in in vivo situations. It has been observed that most of these sensors work with single-mode optical fibers (SMF) in a spectral range of 1550 nm, while only some work in the visible spectrum (Vis); the vast majority, operate through fiber Bragg gratings (FBG), long-period fiber gratings (LPFG), and interferometers. These sensors have brought great advances to the measurement of vital signs, especially with regard to respiratory rate; however, many express the possibility of monitoring other vital signs through mathematical calculations, algorithms, or auxiliary devices. Their advantages due to miniaturization, immunity to electromagnetic interference, and the absence of a power source makes them truly desirable for everyday use at all times.
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Tecnología de Fibra Óptica , Monitoreo Fisiológico/métodos , Algoritmos , Frecuencia Cardíaca , Humanos , Interferometría , Fibras Ópticas , Signos VitalesRESUMEN
Resumo Objetivo: Observar o grau de concordância das variáveis analisadas entre os dispositivos IOL Master 500 e Pentacam AXL e descrever as medias Métodos: Foram analisados 35 prontuários, totalizando 61 olhos. Todos os pacientes se submeteram à avaliação biométrica nos dois dispositivos, no período de agosto de 2018 a agosto de 2019. Os dados coletados foram: idade, sexo, profundidade da câmara anterior, comprimento axial, K1, K2, poder dióptrico da LIO e alvo refracional. Resultados: As médias das variáveis analisadas entre os dispositivos de biométricos óptica em questão tiveram diferença estatisticamente significante (p<0,05). A regressão linear não apontou influência de nenhuma das variáveis da câmara anterior na diferença de valores do poder dióptrico da LIO e do alvo refracional entre os dispositivos. Conclusão: Não houve concordância estatística entre os dispositivos para as variáveis analisadas. Portanto, deve se evitar intercambiar o uso do Pentacam AXL com o IOL Master 500.
Abstract Objective: Observe the agreement between IOL Master 500 and Pentacam AXL and describe the averages. Methods: We analyzed 35 medical records, totaling 61 eyes. All patients underwent biometric evaluation on both devices from August 2018 to August 2019. The data collected were: age, gender, anterior chamber depth, axial length, K1, K2, biometrics and IOL target. Results: The averages of the variables analyzed between the optical biometric devices in question had a statistically significant difference (p <0.05). Linear regression showed no influence of any anterior chamber variables on the difference in biometrics and target values between the devices. Conclusion: There was no statistical agreement between the devices for the analyzed variables. Therefore, the interchange of Pentacam AXL with IOL Master 500 should be avoided.
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Humanos , Masculino , Persona de Mediana Edad , Anciano , Refracción Ocular , Biometría , Longitud Axial del Ojo , Lentes Intraoculares Multifocales , InterferometríaRESUMEN
RESUMEN La cirugía refractiva corneal es una buena opción para corregir el defecto refractivo de los pacientes y lograr una buena visión sin el uso de espejuelos o lentes de contacto; pero cuando no es posible, las lentes fáquicas constituyen una elección viable, especialmente en pacientes jóvenes que mantienen la acomodación. Se presenta el caso de una paciente con antecedentes de implante de lente fáquica desde hacía 13 años, quien acudió al Instituto Cubano de Oftalmología "Ramón Pando Ferrer" por disminución de la visión en ambos ojos. Se destaca la importancia en la obtención de las medidas biométricas, especialmente la longitud axil, si esta se modifica después del implante de la lente fáquica para el correcto cálculo de la lente a implantar y la obtención del buen resultado refractivo. La interferometría óptica es el mejor modo de obtener estas medidas y la longitud axil no parece modificarse con la presencia de una lente fáquica(AU)
ABSTRACT Corneal refractive surgery is a good option to correct the refractive defect and achieve good vision without the use of eyeglasses or contact lenses. When it is not possible, phakic lenses are a viable choice, particularly in young patients who maintain accommodation. A case is presented of a female patient with an antecedent of phakic lens implantation 13 years before who presents at Ramón Pando Ferrer Cuban Institute of Ophthalmology with vision reduction in both eyes. Mention should be made of the importance of obtaining biometric measurements, especially of the axial length, if it changes after phakic lens implantation, for accurate calculation of the lens to be implanted and the achievement of a good refractive result. Optical interferometry is the best way to obtain those measurements, and axial length does not seem to change with the presence of a phakic lens(AU)
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Humanos , Femenino , Persona de Mediana Edad , Extracción de Catarata/métodos , Procedimientos Quirúrgicos Refractivos , Lentes Intraoculares Fáquicas/efectos adversos , Interferometría/métodosRESUMEN
ABSTRACT Purpose: To compare the postoperative refractive predictability of IOLMaster 500 and Pentacam HR on the basis of keratometry and anterior chamber depth values in eyes with an indication for multifocal intraocular lens (IOL) implantation. Methods: This was a retrospective study conducted on 118 eyes treated with phacoemulsification and multifocal intraocular lens implantation. Only the eyes that achieved emmetropia in the dynamic refraction performed on postoperative day 30 were included. Haigis' formula was used in each case to calculate the intraocular lens power, and the intraocular lens with the target refraction closest to emmetropia was implanted. Four lens calculation scenarios were tested by combining keratometry and anterior chamber depth measurements obtained using the two devices. Results: IOLMaster 500 and Pentacam HR differed with regard to mean keratometry (D 0.07 ± 0.03 D; p=0.0065) and anterior chamber depth (D 0.08 ± 0.01 mm; p<0.001). In the analysis of covariance, the following differences were obtained using the Haigis' formula when confronted with the biometric values obtained by inserting keratometry and anterior chamber depth values, respectively: Penta/IOL x IOL/Penta (0.13 ± 0.03; p<0.0001); Penta/Penta × IOL/Penta (0.13 ± 0.03; p<0.0001); Penta/IOL × IOL/IOL (0.11 ± 0.03; p=0.001); Penta/Penta × IOL/IOL (0.11 ± 0.03; p=0.002); IOL/IOL × IOL/Penta (0.02 ± 0.03; p=0.865); and Penta/IOL × Penta/Penta (0.002 ± 0.03; p=0.99). The difference was smaller when measuring the anterior chamber depth using the IOLMaster 500, regardless of which device was used to measure keratometry. Conclusions: Pentacam HR significantly differed from IOLMaster 500 when calculating keratometry. As regards the anterior chamber depth, the two devices were equally accurate.
RESUMO Objetivo: Comparar a previsibilidade refrativa pós-operatória do IOLMaster 500 e Pentacam HR com base nos valores de ceratometria e profundidade de câmara anterior nos olhos com indicação de implante de lentes intraoculares multifocais. Métodos: Estudo retrospectivo realizado em 118 olhos tratados com facoemulsificação e implante de lentes intraoculares multifocal. Apenas os olhos que atingiram a emetropia na refração dinâmica no 30º dia pós-operatório foram incluídos. A fórmula de Haigis foi usada em cada caso para calcular o poder das lentes intraoculares, e a lente intraocular com a refração alvo mais próxima da emetropia foi implantada. Cenários de cálculo de quatro lentes foram testados pela combinação de medidas de ceratometria e profundidade de câmara anterior obtidas usando os dois dispositivos. Resultados: IOLMaster 500 e Pentacam HR diferiram quanto à média de ceratometria (D 0,07 ± 0,03 D; p=0,0065) e profundidade de câmara anterior (D 0,08 ± 0,01 mm; p<0,001). Na análise da covariância, as seguintes diferenças foram obtidas usando a fórmula de Haigis quando confrontadas com os valores biométricos obtidos pela inserção dos valores de ceratometria e profundidade de câmara anterior, respectivamente: Penta/IOL x IOL/Penta (0,13 ± 0,03; p<0,0001); Penta/Penta x IOL/Penta (0,13 ± 0,03; p<0,0001); Penta/IOL x IOL/IOL (0,11 ± 0,03; p=0,001); Penta/Penta x IOL/IOL (0,11 ± 0,03; p=0,002); IOL/IOL x IOL/Penta (0,02 ± 0,03; p=0,865); Penta/IOL x Penta/Penta (0,002 ± 0,03; p=0,99). A diferença foi menor ao medir a profundidade da câmara anterior usando o IOLMaster 500, independentemente de qual dispositivo foi usado para medir a ceratometria. Conclusões: O Pentacam HR diferiu significativamente do IOLMaster 500 no cálculo de ceratometria. Quanto à profundidade da câmara anterior, os dois dispositivos foram igualmente precisos.
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Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Facoemulsificación/métodos , Córnea/patología , Topografía de la Córnea/instrumentación , Implantación de Lentes Intraoculares/métodos , Lentes Intraoculares Multifocales , Cámara Anterior/patología , Periodo Posoperatorio , Valores de Referencia , Refracción Ocular/fisiología , Factores de Tiempo , Agudeza Visual/fisiología , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Biometría , Resultado del Tratamiento , Córnea/diagnóstico por imagen , Interferometría/instrumentación , Interferometría/métodos , Cámara Anterior/diagnóstico por imagenRESUMEN
PURPOSE: To compare the postoperative refractive predictability of IOLMaster 500 and Pentacam HR on the basis of keratometry and anterior chamber depth values in eyes with an indication for multifocal intraocular lens (IOL) implantation. METHODS: This was a retrospective study conducted on 118 eyes treated with phacoemulsification and multifocal intraocular lens implantation. Only the eyes that achieved emmetropia in the dynamic refraction performed on postoperative day 30 were included. Haigis' formula was used in each case to calculate the intraocular lens power, and the intraocular lens with the target refraction closest to emmetropia was implanted. Four lens calculation scenarios were tested by combining keratometry and anterior chamber depth measurements obtained using the two devices. RESULTS: IOLMaster 500 and Pentacam HR differed with regard to mean keratometry (D 0.07 ± 0.03 D; p=0.0065) and anterior chamber depth (D 0.08 ± 0.01 mm; p<0.001). In the analysis of covariance, the following differences were obtained using the Haigis' formula when confronted with the biometric values obtained by inserting keratometry and anterior chamber depth values, respectively: Penta/IOL x IOL/Penta (0.13 ± 0.03; p<0.0001); Penta/Penta × IOL/Penta (0.13 ± 0.03; p<0.0001); Penta/IOL × IOL/IOL (0.11 ± 0.03; p=0.001); Penta/Penta × IOL/IOL (0.11 ± 0.03; p=0.002); IOL/IOL × IOL/Penta (0.02 ± 0.03; p=0.865); and Penta/IOL × Penta/Penta (0.002 ± 0.03; p=0.99). The difference was smaller when measuring the anterior chamber depth using the IOLMaster 500, regardless of which device was used to measure keratometry. CONCLUSIONS: Pentacam HR significantly differed from IOLMaster 500 when calculating keratometry. As regards the anterior chamber depth, the two devices were equally accurate.
Asunto(s)
Cámara Anterior/patología , Córnea/patología , Topografía de la Córnea/instrumentación , Implantación de Lentes Intraoculares/métodos , Lentes Intraoculares Multifocales , Facoemulsificación/métodos , Anciano , Cámara Anterior/diagnóstico por imagen , Biometría , Córnea/diagnóstico por imagen , Femenino , Humanos , Interferometría/instrumentación , Interferometría/métodos , Masculino , Persona de Mediana Edad , Periodo Posoperatorio , Valor Predictivo de las Pruebas , Valores de Referencia , Refracción Ocular/fisiología , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento , Agudeza Visual/fisiologíaRESUMEN
In this paper, we report the development of a portable energy-efficient interrogator (Perrogator) for wavelength-based optical sensors. The interrogator is based on a compact solution encompassing a white light source and the spectral convolution between the sensor and a tunable filter, which is acquired by a photodetector, where a microcontroller has two functions: (i) To control the filter tuning and to (ii) acquire the photodetector signal. Then, the data is sent to a single-board computer for further signal processing. Furthermore, the employed single-board computer has a Wi-Fi module, which can be used to send the sensors data to the cloud. The proposed approach resulted in an interrogator with a resolution as high as 3.82 pm (for 15.64 nm sweeping range) and maximum acquisition frequency of about 210 Hz (with lower resolution ~15.30 pm). Perrogator was compared with a commercial fiber Bragg grating (FBG) interrogator for strain measurements and good agreement between both devices was found (1.226 pm/µÎµ for the commercial interrogator and 1.201 pm/µÎµ for the proposed approach with root mean square error of 0.0144 and 0.0153, respectively), where the Perrogator has the additional advantages of lower cost, higher portability and lower energy consumption. In order to demonstrate such advantages in conjunction with the high acquisition frequency allowed us to demonstrate two wearable applications using the proposed interrogation device over FBG and Fabry-Perot interferometer (FPI) sensors. In the first application, an FBG-embedded smart textile for knee angle assessment was used to analyze the gait of a healthy person. Due to the capability of reconstructing the FBG spectra, it was possible to employ a technique based on the FBG wavelength shift and reflectivity to decouple the effects of the bending angle and axial strain on the FBG response. The measurement of the knee angle as well as the estimation of the angular and axial displacements on the grating that can be correlated to the variations of the knee center of rotation were performed. In the second application, a FPI was embedded in a chest band for simultaneous measurement of breath and heart rates, where good agreement (error below 5%) was found with the reference sensors in all analyzed cases.
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Marcha/fisiología , Determinación de la Frecuencia Cardíaca/instrumentación , Articulación de la Rodilla/fisiología , Procesamiento de Señales Asistido por Computador , Dispositivos Electrónicos Vestibles , Diseño de Equipo , Tecnología de Fibra Óptica/instrumentación , Frecuencia Cardíaca/fisiología , Determinación de la Frecuencia Cardíaca/métodos , Humanos , Interferometría/instrumentación , Respiración , Tecnología Inalámbrica/instrumentaciónRESUMEN
RESUMEN La interferometría de coherencia óptica es un procedimiento esencial para calcular la potencia óptica de la lente intraocular. La presente revisión describe la evolución de la biometría óptica por interferometría, las nuevas plataformas, las características técnicas, los parámetros de calibración, la interpretación de los resultados y las situaciones especiales con indicación de cirugía de catarata. Para efectuar el trabajo fueron consultadas las bases de datos de la plataforma Infomed, específicamente en la Biblioteca Virtual de Salud, PubMed, Cochrane Database-Wiley Online Library, LILACS y Scielo. El IOL Máster favorece la medición de los parámetros biométricos oculares, ya que realiza mediciones sólidas y repetibles que incluye fórmulas de cuarta generación para el cálculo de potencia de lentes intraoculares. Actualmente se dispone en el mercado de varias plataformas para la biometría ocular usando los métodos interferométricos de alta resolución que tienen el potencial de mejorar significativamente los resultados refractivos. Estos estudios son de alta predictibilidad, lo cual permite obtener una buena agudeza visual y evita la sorpresa refractiva((AU)
ABSTRACT Optical coherence interferometry is an essential procedure for calculating the optical power of the intraocular lens. The present review describes the evolution of optical biometry by interferometry, the new platforms, technical features, calibration parameters, interpretation of results, and special situations in which cataract surgery is indicated. Information was collected from the databases on the Infomed platform, specifically the Virtual Health Library, PubMed, Cochrane Database-Wiley Online Library, LILACS and Scielo. IOL Master facilitates the measurement of ocular biometric parameters, since it performs solid, repeatable measurements that include fourth-generation formulas for the calculation of intraocular lens power. Several ocular biometry platforms are currently available in the market which use high resolution interferometric methods with the potential to significantly improve refractive results. These studies are characterized by their high predictability, making it possible to obtain good visual acuity and avoid refractive surprise(AU)
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Humanos , Extracción de Catarata/efectos adversos , Biometría/métodos , Tomografía de Coherencia Óptica/métodos , Interferometría/métodos , Literatura de Revisión como Asunto , Bases de Datos BibliográficasRESUMEN
This study evaluated the effect of alumina-blasted/acid-etched (AB/AE) or microabrasive blasting (C3-Microblasted) surface treatment on the osseointegration of commercially-pure Ti (grade II) and Ti-6Al-4V alloy (grade V) implants compared to as-machined surfaces. Surface characterization was performed by scanning electron microscopy and optical interferometry (IFM) to determine roughness parameters (Sa and Sq, nâ¯=â¯3 per group). One-hundred forty-four implants were placed in the radii of 12 beagle dogs, for histological (nâ¯=â¯72, bone-to-implant contact - BIC and bone-area-fraction occupancy -BAFO) and torque to interface failure test at 3 and 6 weeks (nâ¯=â¯72). SEM and IFM revealed a significant increase in surface texture for AB/AE and C3-Microblasted surfaces compared to machined surface, regardless of titanium substrate. Torque-to-interface failure test showed significant increase in values from as-machined to AB/AE and to C3-Microblasted. Considering time in vivo, alloy grade, and surface treatment, the C3-microblasted presented higher mean BIC values relative to AB/AE and machined surfaces for both alloy types. BAFO levels were significantly higher for both textured surfaces groups relative to the machined group at 3 weeks, but differences were not significant between the three surfaces for each alloy type at 6 weeks. Surface treatment resulted in roughness that improved osseointegration in Grade II and V titanium substrates.
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Grabado Ácido Dental/métodos , Óxido de Aluminio/química , Implantes Dentales , Oseointegración , Titanio/química , Aleaciones , Animales , Perros , Interferometría , Masculino , Microscopía Electrónica de Rastreo , Propiedades de Superficie , Resistencia a la Tracción , TorqueRESUMEN
Abstract Purpose: To report the prevalence and analyse corneal astigmatism patterns in cataract surgery candidates. Methods: Researchers examined 2136 eyes from 1204 patients for cataract surgery from 1 January to 31 December 2016. All the candidates were evaluated with partial coherence interferometry (IOLMaster). The results were analysed statistically in relation to qualitative and quantitative variables. Results: The mean age of the patients was 71.9 years with a female predominance. Mean corneal astigmatism was 1.0 dioptre (D). Against the rule (ATR) astigmatism increased with age. Women presented with steeper corneas than men. In those patients who had both eyes measured, we found strong correlations between amount of right and left eye astigmatism, axis and keratometry. Overall, 39% of the eyes had corneal astigmatism > 1.00 D and 19% >1.50 D. Conclusions: A significant percentage of our population presents with corneal astigmatism > 1.00 D with a shift from WTR (with the rule) to ATR with increasing age. Our findings, in a population that has never been described before, will be helpful to surgeons to enhance surgical techniques, patients to improve visual outcomes, IOL (intraocular lens) manufacturers to make better designs and health agents to optimise resources.
Resumo Objetivo: Relatar a prevalência e analisar os padrões de astigmatismo corneano em candidatos à cirurgia de catarata. Métodos: Os pesquisadores examinaram 2136 olhos de 1204 pacientes a cirurgia de catarata de 1 de janeiro a 31 de dezembro de 2016. Todos os candidatos foram avaliados com interferometria de coerência parcial (IOLMaster). Os resultados foram analisados estatisticamente em relação às variáveis qualitativa e quantitativa. Resultados: A média de idade dos pacientes foi de 71,9 anos, com predomínio do sexo feminino. A média de astigmatismo corneano foi de 1,0 dioptria (D). Contra a regra (ATR), o astigmatismo aumentou com a idade. As mulheres apresentaram córneas mais íngremes que os homens. Nos pacientes que tiveram os dois olhos medidos, encontramos fortes correlações entre quantidade de astigmatismo nos olhos direito e esquerdo, eixo e ceratometria. No geral, 39% dos olhos tinham astigmatismo corneano >1,00 D, e 19% > 1,50 D. Conclusões: Uma percentagem significativa da nossa população apresenta astigmatismo corneano >1,00, D com uma mudança de WTR (a favor da regra) para ATR (contra a regra) com o aumento da idade. Nossas descobertas em uma população que nunca foi descrita antes serão úteis para os cirurgiões melhorarem suas técnicas cirúrgicas, os pacientes melhorarem seus resultados visuais, os fabricantes de LIOs (lentes intraoculares) criarem projetos melhores, e os agentes de saúde otimizarem os recursos.
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Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Astigmatismo/epidemiología , Facoemulsificación/estadística & datos numéricos , Córnea/diagnóstico por imagen , Interferometría , Astigmatismo/fisiopatología , Extracción de Catarata/estadística & datos numéricos , Prevalencia , Biometría/instrumentación , Longitud Axial del Ojo , Imagen Óptica/instrumentación , Cámara AnteriorRESUMEN
INTRODUCTION: While the combined effect of microwave irradiation with cleansing solutions on denture base materials has been investigated, the effects of only using microwave irradiation and, more importantly, in a long-term basis, was not studied yet. OBJECTIVE: The purpose of this study was to evaluate the effect of a long-term repeated microwaving on the dimensional, color and translucency stability of acrylic and polyamide denture base materials. MATERIAL AND METHODS: Thirty two specimens (32 mm x 10 mm x 2.5 mm) from polyamide (Valplast) and PMMA (Vertex Rapid Simplified) denture base materials were made. Eight specimens from each material were immersed in distilled water (control) and 8 were subjected to microwave exposure at 450 W for 3 minutes for a period simulating 224 days of daily disinfection. Linear dimension, color change (ΔE*) and translucency parameter (TP) were measured at baseline and after certain intervals up to 224 cycles of immersion, using a digital calliper and a portable colorimeter. The results were analysed using two-way repeated measures ANOVA to estimate possible differences among predetermined cycles and material type. Regression analysis was also performed to estimate the trend of changes with time. Statistical evaluations performed at a significance level of 5%. RESULTS: Data analysis showed significant changes in length at baseline with an increasing number of cycles (p<0.05) and a significant interaction of cycle-material (p<0.001). The ΔΕ* parameter was significantly higher with a higher number of cycles (p<0.001), but it did not vary between materials (p>0.05). TP decreased similarly in both materials following microwave action but in a significantly higher level for Valplast (p<0.001). CONCLUSIONS: The results indicated that long-term repeated microwaving affects linear dimensional, color and translucency changes of both materials. Differences between PMMA and polyamide material were noted only in dimension and translucency changes.