Cutaneous leishmaniasis (CL) is a neglected tropical disease that requires novel tools for its understanding, diagnosis, and treatment follow-up. In the cases of other cutaneous pathologies, such as cancer or cutaneous ulcers due to diabetes, optical diffuse reflectance-based tools and methods are widely used for the investigation of those illnesses. These types of tools and methods offer the possibility to develop portable diagnosis and treatment follow-up systems. In this article, we propose the use of a three-layer diffuse reflectance model for the study of the formation of cutaneous ulcers caused by CL. The proposed model together with an inverse-modeling procedure were used in the evaluation of diffuse-reflectance spectral signatures acquired from cutaneous ulcers formed in the dorsal area of 21 golden hamsters inoculated with Leishmanisis braziliensis. As result, the quantification of the model’s variables related to the main biological parameters of skin were obtained, such as: diameter and volumetric fraction of keratinocytes, collagen; volumetric fraction of hemoglobin, and oxygen saturation. Those parameters show statistically significant differences among the different stages of the CL ulcer formation. We found that these differences are coherent with histopathological manifestations reported in the literature for the main phases of CL formation.

This article concerns the characterization of the stability and performance of a motorized stage used in laser direct writing lithography. The system was built from commercial components and commanded by G-code. Measurements use a pseudo-periodic-pattern (PPP) observed by a camera and image processing is based on Fourier transform and phase measurement methods. The results report that the built system has a stability against vibrations determined by peak-valley deviations of 65 nm and 26 nm in the x and y directions, respectively, with a standard deviation of 10 nm in both directions. When the xy-stage is in movement, it works with a resolution of 0.36 μm, which is an acceptable value for most of research and development (R and D) microtechnology developments in which the typical feature size used is in the micrometer range.

Thin films are a type of coating that have a very wide spectrum of applications. They may be used as single layers or composed in multilayer stacks, which significantly extend their applications. One of the most commonly used material for thin films is silicon dioxide, SiO₂. Although there are other tools that can be used to measure the thickness of SiO₂ films, these tools are very complex and sophisticated. In this article, we propose the use of an exponential two-layer light-material interaction model, throughout its diffuse reflectance spectra, as an alternative for the measurement of the thickness of evaporated SiO₂ on Si wafers. The proposed model is evaluated experimentally by means of a 980-nm-thick SiO₂ layer evaporated on a Si wafer. The results show that the proposed model has a strong correlation with the thickness measurements obtained using commercial equipment.

Este trabajo muestra un mecanismo de acción, un diseño y una fabricación de un nuevo dispositivo de escaneo - un micro-espejo. Los micro-espejos se pueden encontrar en los lectores de códigos de barras, así como en los micro proyectores, en sistemas de tomografía óptica coherente, o en los filtros ajustables de espectrómetros. El proceso de formación del nuevo dispositivo nos llevó a describir y discutir los problemas relacionados con la fabricación de MEMS (sistemas microelectrónicos). En primer lugar, se da una terminología y una breve introducción al campo de los microsistemas. A continuación, se explica un concepto del nuevo micro-espejo de escanéo. El dispositivo es accionado por dos pares de actuadores termo-bimorfos. Un diseño especial permite mantener la distancia constante desde el centro del espejo a la fuente de luz durante el proceso de escaneo. El dispositivo se implementó en dos versiones: un micro-espejo con un grado de libertad y un micro-espejo con dos grados de libertad. Se describe un proceso de fabricación para los dos tipos del dispositivo que utiliza dos tipos diferentes de sustrato. El primer tipo de sustrato corresponde a una oblea de silicio estándar, el segundo substrato corresponde a un SOI (Silicon-On-Insulator). El proceso con la oblea de silicio estándar fue complicado y causó muchos problemas. Cambiar el sustrato a SOI ayudó a resolver algunos de ellos, pero no permitió evitar algunos nuevos. Sin embargo, el sustrato SOI da mejores resultados y se encuentra que es preferible fabricar dispositivos MEMS de este tipo.

Glass microscopes slides are widely used as in situ base-substrates carrying diverse micro-fabricated systems or elements. For such purposes, the micro-fabrication process consists in transferring a pre-defined design onto the substrate made of a glass microscope slide. This is known as patterning, which is a technique that can also be used in transferring specific designs that allows region of interest (ROI) recovery under the microscope. In those cases, two main challenges appear: 1) Disturbances in light transmission should remain minimum to keep the high quality of observation of the object of interest under the microscope. 2) The pattern-size should then be small enough but, however, larger than the diffraction limit to be observable satisfactorily for positioning purposes. In this article, we present the procedures involved in the microfabrication of Pseudo-Periodic Patterns (PPP) encrypting the absolute position of an extended area. Those patterns are embedded in Pétri dishes in order to allow the highaccurate retrieval of absolute position and orientation. The presented microfabrication is based in a technique known as lift-off, which after parameter adjustment, allows the obtaining of PPP fulfilling the two previously mentioned requirements. The results report on PPP realized on glass microscope slides and composed by 2µm side dots made of aluminum with a thickness of 30nm.

Vision is a convenient tool for position measurements. In this paper, we present several applications in which a reference pattern can be defined on the target for a priori knowledge of image features and further optimization by software. Selecting pseudoperiodic patterns leads to high resolution in absolute phase measurements. This method is adapted to position encoding of live cell culture boxes. Our goal is to capture each biological image along with its absolute highly accurate position regarding the culture box itself. Thus, it becomes straightforward to find again an already observed region of interest when a culture box is brought back to the microscope stage from the cell incubator where it was temporarily placed for cell culture. In order to evaluate the performance of this method, we tested it during a wound healing assay of human liver tumor-derived cells. In this case, the procedure enabled more accurate measurements of the wound healing rate than the usual method. It was also applied to the characterization of the in-plane vibration amplitude from a tapered probe of a shear force microscope. The amplitude was interpolated by a quartz tuning fork with an attached pseudo-periodic pattern. Nanometer vibration amplitude resolution is achieved by processing the pattern images. Such pictures were recorded by using a common 20x magnification lens.