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This study demonstrates a full-color near-eye holographic display capable of superimposing color virtual scenes with 2D, 3D, and multiple objects with extended depth upon a real scene, which also has the ability to present different 3D information depending on the focus of the user's eyes using a single computer-generated hologram per color channel. Our setup makes use of a hologram generation method based on two-step propagation and the singular value decomposition of the Fresnel transform impulse response function to efficiently generate the holograms of the target scene. Then, we test our proposal by implementing a holographic display that makes use of a phase-only spatial light modulator and time-division multiplexing for color reproduction. We demonstrate the superior quality and computation speed of this approach compared with other hologram generation techniques with both numerical and experimental results.

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Introducción: La microscopía holográfica digital ha permitido a la microscopía óptica hacer uso de herramientas numéricas y computacionales; y esto, a su vez, ha favorecido múltiples avances en el estudio de las células y los tejidos en diferentes campos de la medicina y otras ciencias afines. Objetivo: Describir las características histológicas y morfométricas de los folículos tiroideos humanos con la microscopía holográfica digital. Métodos: Se realizó, desde el punto de vista histomorfométrico, un estudio descriptivo y transversal de folículos tiroideos humanos utilizando una instalación de microscopía holográfica digital. Se empleó la técnica de inclusión en parafina y tinción de hematoxilina-eosina para el procesamiento de las muestras. Se realizaron de 10 a 12 capturas de hologramas por muestra y el método de doble propagación para la reconstrucción de los hologramas. Se calculó el área, el perímetro, el diámetro mayor y menor de los folículos y cavidades foliculares y se realizaron reconstrucciones de imágenes holográficas en tres dimensiones. Se determinó como medida de tendencia central la media aritmética y como medida de dispersión la desviación típica o estándar. Resultados: Parámetros foliculares: área (5140,31 ± 1126,71 µm2); perímetro (2961,54 ± 71,2 µm); diámetro mayor:(921,17 ± 24,34 µm); diámetro menor: (746,67 ± 18,08 µm); altura del epitelio (7,92 ± 0,96). Cavidades foliculares: área (3686,18 ±1023,52 µm2); diámetro mayor: (698,86 ± 19,55 µm) y diámetro menor: (581,15 ± 13,82 µm). Conclusiones: Existen parámetros foliculares, determinados mediante la microscopía holográfica digital, no reportados por la literatura consultada, que resultan de interés en el estudio histológico de los folículos tiroideos humanos(AU)

Introduction: Digital holographic microscopy has made it possible to incorporate the use of numerical and computer tools into optical microscopy. This in turn has led to great progress in the study of cells and tissues in several fields of medicine and related sciences. Objective: Describe the histological and morphometric characteristics of human thyroid follicles using digital holographic microscopy. Methods: A descriptive cross-sectional histomorphometric study was conducted of human thyroid follicles using a digital holographic microscopy facility. Sample processing was based on inclusion technique by paraffin and hematoxylin-eosin staining. Ten to twelve holographic captures were made per sample, and the double propagation method was used for holographic reconstruction. Estimation was carried out of the area, perimeter, and greatest and smallest diameter of follicles and follicular cavities, and tri-dimensional reconstructions were made of holographic images. Arithmetic mean was determined as the measure of central tendency, and typical or standard deviation as the measure of dispersion. Results: Follicular parameters: area (5 140.31 ± 1 126.71 µm2); perimeter (2 961.54 ± 71.2 µm); greatest diameter (921.17 ± 24.34 µm); smallest diameter (746.67 ± 18.08 µm); epithelial height (7.92 ± 0.96). Follicular cavities: area (3 686.18 ± 1 023.52 µm2); greatest diameter (698.86 ± 19.55 µm); smallest diameter (581.15 ± 13.82 µm). Conclusions: A number of follicular parameters determined by digital holographic microscopy have not been reported by the literature consulted, and they are of interest to the histological study of human thyroid follicles(AU)

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Se realizó un estudio descriptivo y transversal de la corteza cerebelosa humana, desde el punto de vista histomorfométrico, desde enero hasta septiembre del 2015, con el empleo de la microscopia holográfica digital instalada en el Departamento de Holografía Digital de la Universidad de Oriente en Santiago de Cuba, con vistas efectuar mediciones que permitieran establecer comparaciones con otros estudios. Los cálculos mostraron el grosor de las capas molecular y granulosa, el área, el perímetro, los diámetros mayores y menores del cuerpo y el núcleo de las células de Purkinje. Asimismo, se tomaron imágenes holográficas en tres dimensiones, que posibilitaron concluir la existencia de parámetros determinados mediante este procedimiento, los que no habían sido notificados y que resultan de interés en el estudio histológico de la corteza cerebelosa

A descriptive and cross-sectional study of the human cerebellar cortex, from the histomorphometric point of view, was carried out from January to September, 2015, using the digital holographic microscopy installed in the Digital Holography Department of Oriente University in Santiago de Cuba, aimed at making measurings that allowed to establish comparisons with other studies. The calculations showed the thickness of the molecular and granular layers, the area, perimeter, greatest and smallest diameters of the body and Purkinje cells nucleus. Also, holographic images in three dimensions were taken, that facilitated to conclude the existence of certain parameters by means of this procedure, those that had not been notified and are of interest in the histological study of the cerebellar cortex

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AIM: FabI is a key enzyme in the fatty acid metabolism of Gram-positive bacteria such as Staphylococcus aureus and is an established drug target for known antibiotics such as triclosan. However, due to increasing antibacterial resistance, there is an urgent demand for new drug discovery. Recently, aminopyridine derivatives have been proposed as promising competitive inhibitors of FabI. METHODS: In the present study, holographic structure-activity relationship (HQSAR) analyses were employed for determining structural contributions of a series containing 105 FabI inhibitors. RESULTS & CONCLUSION: The final HQSAR model was robust and predictive according to statistical validation (q2 and r2pred equal to 0.696 and 0.854, respectively) and could be further employed to generate fragment contribution maps. Then, final HQSAR model together with FabI active site information can be useful for designing novel bioactive ligands.

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Se efectuó una revisión bibliográfica exhaustiva sobre la microscopia holográfica digital y se ofrece una información actualizada sobre esta novedosa técnica de registro óptico en el país, así como de sus fundamentos teóricos y principales aplicaciones en el campo de la biología, para que pueda ser consultada por estudiantes y profesionales de la medicina y ciencias afines, con vistas a promover la realización de futuras investigaciones relacionadas con dicha técnica

An exhaustive literature review on the digital holographic microscopy was carried out and an updated information on this novel technique of optic record, its theoretical foundations and main uses in the field of biology in the country is offered, so that it can be consulted by students and professionals of medicine and similar sciences, aimed at promoting the realization of future investigations related to this technique

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Acquired immunodeficiency syndrome is a public health problem worldwide caused by the Human immunodeficiency virus (HIV). Treatment with antiretroviral drugs is the best option for viral suppression, reducing morbidity and mortality. However, viral resistance in HIV-1 therapy has been reported. HIV-1 integrase (IN) is an essential enzyme for effective viral replication and an attractive target for the development of new inhibitors. In the study reported here, two- and three-dimensional quantitative structure-activity relationship (2D/3D-QSAR) studies, applying hologram quantitative structure-activity relationship (HQSAR) and comparative molecular field analysis (CoMFA) methods, respectively, were performed on a series of tricyclic phthalimide HIV-1 IN inhibitors. The best HQSAR model (q (2) = 0.802, r (2) = 0.972) was obtained using atoms, bonds, and connectivity as the fragment distinction, a fragment size of 2-5 atoms, hologram length of 61 bins, and six components. The best CoMFA model (q (2) = 0.748, r (2) = 0.974) was obtained with alignment of all atoms of the tricyclic phthalimide moiety (alignment II). The HQSAR contribution map identified that the carbonyl-hydroxy-aromatic nitrogen motif made a positive contribution to the activity of the compounds. Furthermore, CoMFA contour maps suggested that bulky groups in meta and para positions in the phenyl ring would increase the biological activity of this class. The conclusions of this work may lead to a better understanding of HIV-1 IN inhibition and contribute to the design of new and more potent derivatives.

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Recently an optoelectronic holography system was deployed in the clinic with the purpose of quantifying the tympanic membrane (TM) displacements of various mammal species, the objective being the understanding of their middle ear biomechanics. The optoelectronic holography system has an in-line configuration where the data gathered is decoded using lensless digital holography with the Fresnel approximation. This paper presents quantitative data obtained from an acoustically excited postmortem chinchilla's TM. To achieve this we used a robust customized windowed unwrapping method to unwrap the noisy optical phase obtained by subtracting phase maps of two recorded holograms and the results were compared with those obtained when using the unwrapping branch-cut algorithm. Additionally, phase maps obtained by the phase-stepping technique were compared applying both unwrapping methods. For in vivo applications particular emphasis is made on post-processing dual-shot-acquisition of holograms as one of various acquisition strategies and algorithms to diminish measurement error due to heartbeat, breathing, and patient's head motion as well as environment induced mechanical disturbances present in a noncontrolled environment, such as in a clinic. By recording only two holograms representing a stationary and deformed state of eardrum, respectively, we can increase the acquisition speed of the camera used to record faster events happening on the TM surface.

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We report the experimental implementation of a new method for generating multiple dynamical optical tweezers, where each one of them is generated with an independent linear polarization state with arbitrary orientation. This also allows an independent simultaneous polarization-rotation control. The laser beam, both for generating multiple traps and polarization control, has been modulated using a single reflective nematic liquid crystal with parallel alignment. We present experimental results of controlled displacement, orientation and rotation of birefringent particles. In addition, a simple method for estimating and canceling out the primary astigmatism present in the system is presented.

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The number of colloidal particles per unit of volume that can be imaged correctly with digital lensless holographic microscopy (DLHM) is determined numerically. Typical in-line DLHM holograms with controlled concentration are modeled and reconstructed numerically. By quantifying the ratio of the retrieved particles from the reconstructed hologram to the number of the seeding particles in the modeled intensity, the limit of concentration of the colloidal suspensions up to which DLHM can operate successfully is found numerically. A new shadow density parameter for spherical illumination is defined. The limit of performance of DLHM is determined from a graph of the shadow density versus the efficiency of the microscope.

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Tuberculosis (TB) still remains one of the most deadly infectious diseases. Mycobacterium tuberculosis thymidine monophosphate kinase (TMPKmt) has emerged as an attractive molecular target for the design of a novel class of anti-TB agents since blocking it will affect the pathways involved in DNA replication. Aiming at shedding some light on structural and chemical features that are important for the affinity of thymidine derivatives to TMPKmt, we have employed a special fragment-based method to develop robust quantitative structure-activity relationship models for a large and chemically diverse series of thymidine-based analogues. Significant statistical parameters (r2= 0.94, q2= 0.76, r2pred= 0.89) were obtained, indicating the reliability of the hologram QSAR model in predicting the biological activity of untested compounds. The 2D model was then used to predict the potency of an external test set, and the predicted values obtained from the HQSAR model were in good agreement with the experimental results. We have accordingly designed novel TMPKmt inhibitors by utilizing the fragments proposed by HQSAR analysis and predicted with good activity in the developed models. The new designed compounds also presented drug-like characteristics based on Lipinski's rule of 5. The generated molecular recognition patterns gathered from the HQSAR analysis combined with quantum mechanics/molecular mechanics (QM/MM) docking studies, provided important insights into the chemical and structural basis involved in the molecular recognition process of this series of thymidine analogues and should be useful for the design of new potent anti-TB agents.

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