RESUMO
We present the proof of concept of a general model that uses the tissue sample transmittance as input to estimate the depth-resolved attenuation coefficient of tissue samples using optical coherence tomography (OCT). This method allows us to obtain an image of tissue optical properties instead of intensity contrast, guiding diagnosis and tissues differentiation, extending its application from thick to thin samples. The performance of our method was simulated and tested with the assistance of a home built single-layered and multilayered phantoms (~100 µm each layer) with known attenuation coefficient on the range of 0.9 to 2.32 mm-1 . It is shown that the estimated depth-resolved attenuation coefficient recovers the reference values, measured by using an integrating sphere followed by the inverse adding doubling processing technique. That was corroborated for all situations when the correct transmittance value is used with an average difference of 7%. Finally, we applied the proposed method to estimate the depth-resolved attenuation coefficient for a thin biological sample, demonstrating the ability of our method on real OCT images.
Assuntos
Modelos Teóricos , Fenômenos Ópticos , Tomografia de Coerência Óptica , Imagens de FantasmasRESUMO
Cadmium selenide/zinc sulfide (CdSe/ZnS) core-shell quantum dots (QDs) embedded in biocompatible materials were thermally and optically characterized with a thermal lens (TL) technique. Transient TL measurements were performed with a mode-mismatched, dual-beam (excitation and probe) configuration. A thermo-optical study of the CdSe/ZnS QDs was performed for different core diameters (3.5, 4.0, 5.2, and 6.6 nm) in aqueous solution and synthetic saliva, and three different core diameters (2.4, 2.9, and 4.1 nm) embedded in restorative dental resin (0.025% by mass). The thermal diffusivity results are characteristic of the biocompatible matrices. The radiative quantum efficiencies for aqueous solution and biofluid materials are dependent on the core size of the CdSe/ZnS core-shell QDs. The results obtained from the fluorescence spectral measurements for the biocompatible materials support the TL results.
Assuntos
Materiais Biocompatíveis/química , Compostos de Cádmio/química , Pontos Quânticos , Compostos de Selênio/química , Sulfetos/química , Compostos de Zinco/química , Teste de Materiais , Tamanho da Partícula , Resinas Sintéticas , Saliva Artificial , Espectrometria de FluorescênciaRESUMO
OBJECTIVE: To report the biometric values and ultrasonographic aspects of the normal eye of the Striped owl (Rhinoptynx clamator). Sample population Twenty-seven healthy, free-living, adult Striped owls from the Ecological Park of Tiete Veterinary Ambulatory (Sao Paulo, Brazil). PROCEDURES: Both eyes of all owls underwent B-mode ultrasonographic examination and biometry was performed for lens axial length (WL), depth of the anterior (AC) and vitreous (VC) chambers, axial length of the globe (LB) and the pecten oculi (LP) of both eyes, using a 12 MHz probe. The owls were manually restrained without sedation and the eyes were topically anesthetized. RESULTS: Biometric and statistical findings were as follows: in the left eye, the means and standard deviations were: LB = 23.76 ± 0.92 mm, WL = 7.79 ± 0.27 mm, AC = 4.27 ± 0.47 mm, VC = 11.36 ± 0.29 mm and LP = 5.69 ± 0.50 mm; in the right eye, the values were: LB = 24.25 ± 0.79 mm, WL = 8.03 ± 0.40 mm, AC = 4.56 ± 0.52 mm, VC = 11.40 ± 0.25 mm, and LP = 5.68 ± 0.41 mm. No significant differences were found between left and right eyes measurements of LB, WL, AC, VC, and LP dimensions. CONCLUSIONS: Ocular ultrasound aspects and biometric values of the Striped owl are reported. The study's results provide means for various ocular measurements. The ultrasound is an easy and safe exam to be performed in the Striped owl's eyes.
Assuntos
Olho/diagnóstico por imagem , Estrigiformes/anatomia & histologia , Animais , Biometria , UltrassonografiaRESUMO
The aim of this work was to assess the effect of an inhibitor acting in the floral differentiation on the physico-chemical characteristics of pineapple fruits and on the effect in the harvest time. Paclobutrazol was used at concentrations of 100, 150, and 200 mg L-1, applied 2, 3 or 4 times in Smooth Cayenne pineapple plants. The treatment did not influence the chemical characteristics of the fruits, and even having some physical alterations, they were within the quality standard for the commercialization. The harvest time was amplified in all the treatments comparing to the control. However, 150 mg L-1 applied twice promoted the best result when analyzing together the harvest time and the fruit fresh matter.
O objetivo deste trabalho foi avaliar o efeito de um inibidor da diferenciação floral nas características físico-químicas dos frutos do abacaxizeiro, bem como, no período de colheita. Utilizou-se paclobutrazol a 100, 150 e 200 mg L-1 aplicados 2, 3 ou 4 vezes, em plantas de abacaxi cv. Smooth Cayenne. Os tratamentos não influenciaram nas características químicas dos frutos, e mesmo alterando algumas características físicas, os frutos permaneceram dentro dos padrões de qualidade para comercialização. O período de colheita foi ampliado em todos os tratamentos comparando-se com o controle, porém, 150 mg L-1 aplicados 2 vezes promoveu melhor resultado analisando-se em conjunto a época de colheita com a massa fresca do fruto.
RESUMO
Microscopic characterization of pathological tissues has one major intrinsic limitation, the small sampling areas with respect to the extension of the tissues. Mapping possible changes on vast tissues and correlating them with large ensembles of clinical cases is not a feasible procedure for studying most diseases, as for instance vision loss related diseases and, in particular, the cataract. Although intraocular lens implants are successful treatments, cataract still is a leading public-health issue that grows in importance as the population increases and life expectancy is extended worldwide. In this work we have exploited the radiation-tissue interaction properties of hard x-rays--very low absorption and scattering--to map distinct lesions on entire eye lenses. At the used synchrotron x-ray photon energy of 20 keV (wavelength lambda=0.062 nm), scattering and refraction are angular resolved effects. It allows the employed x-ray image technique to efficiently characterize two types of lesions in eye lenses under cataractogenesis: distributions of tiny scattering centers and extended areas of fiber cell compaction. The data collection procedure is relatively fast; allowing dozens of samples to be totally imaged (scattering, refraction, and mass absorption images) in a single day of synchrotron beam time. More than 60 cases of canine cataract, not correlated to specific causes, were investigated in this first application of x-rays to image entire lenses. Cortical opacity cases, or partial opacity, could be related to the presence of calcificated tissues at the cortical areas, clearly visible in the images, whose elemental contents were verified by micro x-ray fluorescence as very rich in calcium. Calcificated tissues were also observed at nuclear areas in some cases of hypermature cataract. Total opacity cases without distinguishable amount of scattering centers consist in 70% of the analyzed cases, where remarkable fissure marks owing to extended areas of fiber cell compaction are diagnosed.