Low-cost printed holography for the generation of structured light.

Recently, the study of structured light fields has attracted great interest, which includes their generation and characterization techniques, as well as their application. Most of these techniques rely on the use of expensive devices, such as liquid crystal spatial light modulators or digital micromirror devices that also require specialized knowledge and software. In this work, we present a scheme for producing low-cost amplitude holograms for the generation of structured light fields. We demonstrate the feasibility of this technique by creating a variety of paraxial modes, such as the well-known Laguerre-Gaussian and Hermite-Gaussian beams. We also demonstrate the potential of our technique in solving the phase retrieval problem to generate 2D and 3D holographic images of objects. Finally, we compare our proposal with the typical generation techniques using digital micromirror devices. Our proposal will pave the path for the generation of structured light beams in more affordable ways for the application in undergrad laboratories.

Partially coherent Ince-Gaussian beams.

We report on the study and generation of Ince-Gaussian beams in the spatially partially coherent regime. The inherent random fluctuations both in time and space of these partially coherent fields make their characterization difficult. Our results show that the cross-correlation function (CCF) provides insight into the composition of the Ince-Gaussian beam, as well as into its spatial coherence structure and singularities. Our experimental findings are in very good agreement with the numerical simulations, particularly revealing a rich structure of nodal lines in the CCF.

Morphological transformation of generalized spirally polarized beams by anisotropic media and its experimental characterization.

We present a generalization of the known spirally polarized beams (SPBs) which we will call generalized spirally polarized beams (GSPBs). We characterize in detail both theoretically and experimentally the streamline morphologies of the GSPBs and their transformation by arbitrary polarization optical systems described by complex Jones matrices. We find that the description of the passage of GSPBs through a polarization system is equivalent to the stability theory of autonomous systems of ordinary differential equations. While the streamlines of the GSPB exhibit a spiral geometry, the streamlines of the output field may exhibit spirals, saddles, nodes, ellipses, and stars as well. Using a novel experimental technique based on a Sagnac interferometer, we have been able to generate in the laboratory each one of the different cases of GSPBs and record their corresponding characteristic streamline morphologies.

Accessible quantitative phase imaging in confocal microscopy with sinusoidal-phase synthetic optical holography.

We present a technically simple implementation of quantitative phase imaging in confocal microscopy based on synthetic optical holography with sinusoidal-phase reference waves. Using a Mirau interference objective and low-amplitude vertical sample vibration with a piezo-controlled stage, we record synthetic holograms on commercial confocal microscopes (Nikon, model: A1R; Zeiss: model: LSM-880), from which quantitative phase images are reconstructed. We demonstrate our technique by stain-free imaging of cervical (HeLa) and ovarian (ES-2) cancer cells and stem cell (mHAT9a) samples. Our technique has the potential to extend fluorescence imaging applications in confocal microscopy by providing label-free cell finding, monitoring cell morphology, as well as non-perturbing long-time observation of live cells based on quantitative phase contrast.

Fatal falls in the elderly and the presence of proximal femur fractures.

Fatal falls are frequent and seem to be an increasing problem in the elderly. Especially ground level falls (GLFs) and falls on or from stairs and steps (stairs falls) are worth examining for forensic classification and in order to improve the development of preventive measures. We retrospectively analyzed 261 fatal falls of elderly age 65 + years, which were autopsied at the Institute of Legal Medicine in Munich between 2008 and 2014. After careful screening, the sub-set of all 77 GLFs and 39 stairs falls were analyzed towards socio-demographic characteristics, fall circumstances, injuries, and circumstances of death. A subsequent analysis of GLF cases regarding the presence of proximal femur fractures (PFF) was performed. The injury pattern of the GLFs and the stairs falls clearly differ with a higher share of injuries to the lower extremities in the GLFs. However, the most severely injured body region was the head in both groups (62% of the stairs cases, 49% of the GLF cases). Alcohol as contributing to the fall was seen more frequently in the stairs falls. PFF were not seen in the stairs falls, but then in 18 GLF cases. Yet, for 17 among them (22% of 77), their hip fracture was the only serious injury leading to hospitalization and death. Only one GLF case was already found dead. This finding indicates a potential of avoiding up to 22% of the GLF fatalities by preventing hip fractures by optimized hip protectors or other measures, especially for the elderly aged 75 + years.

3D thickness map reconstruction of dielectric thin films using scattering of surface plasmon polaritons.

Thin films are key elements in the current development of nanotechnology, and their characterization has become an essential task. In this Letter, we report on a technique to reconstruct full 3D maps of dielectric thin films using the scattered light of decoupled surface plasmon polaritons. Patterned magnesium fluoride thin films were fabricated, and their 3D thickness map was fully reconstructed with high (<1 nm) precision. This technique can be applied and easily adjusted to identify inhomogeneities in wide areas (mm2-cm2) of dielectric samples with subnanometer precision, or to characterize the fabrication processes involved in the preparation of patterned multilayered systems.

A deterministic detector for vector vortex states.

Encoding information in high-dimensional degrees of freedom of photons has led to new avenues in various quantum protocols such as communication and information processing. Yet to fully benefit from the increase in dimension requires a deterministic detection system, e.g., to reduce dimension dependent photon loss in quantum key distribution. Recently, there has been a growing interest in using vector vortex modes, spatial modes of light with entangled degrees of freedom, as a basis for encoding information. However, there is at present no method to detect these non-separable states in a deterministic manner, negating the benefit of the larger state space. Here we present a method to deterministically detect single photon states in a four dimensional space spanned by vector vortex modes with entangled polarisation and orbital angular momentum degrees of freedom. We demonstrate our detection system with vector vortex modes from the |[Formula: see text]| = 1 and |[Formula: see text]| = 10 subspaces using classical and weak coherent states and find excellent detection fidelities for both pure and superposition vector states. This work opens the possibility to increase the dimensionality of the state-space used for encoding information while maintaining deterministic detection and will be invaluable for long distance classical and quantum communication.

On-demand tailored vector beams.

We introduce an effective optical system to produce optical beams with arbitrary, inhomogeneous polarization states. Using our system, we are capable of generating vector beams with discretionarily chosen transverse complex fields in a straightforward way. We generate several different instances of well-known vector beams and the less common spirally polarized vector beams, as well as a full Poincaré beam. We visually show the continual transition between azimuthally and radially polarized beams via a collection of spirally polarized beams. We experimentally determine the polarization states of the generated beams and quantitatively assess the performance of our system. We find that the measured polarization distributions accurately coincide with the intended input polarization distributions.

Geometric phase morphology of Jones matrices.

We demonstrate an innovative technique based on the Pancharatnam-Berry phase that can be used to determine whether an optical system characterized by a Jones matrix is homogeneous or inhomogeneous, containing orthogonal or nonorthogonal eigenpolarizations, respectively. Homogeneous systems have a symmetric geometric phase morphology showing line dislocations and sets of polarization states with an equal geometric phase. In contrast, the morphology of inhomogeneous systems exhibits phase singularities, where the Pancharatnam-Berry phase is undetermined. The results show an alternative to extract polarization properties such as diattenuation and retardance, and can be used to study the transformation of space-variant polarized beams.

Digital generation of partially coherent vortex beams.

We present an experimental technique to generate partially coherent vortex beams with an arbitrary azimuthal index using only a spatial light modulator. Our approach is based on digitally simulating the intrinsic randomness of broadband light passing through a spiral phase plate. We illustrate the versatility of the technique by generating partially coherent beams with different coherence lengths and orbital angular momentum content, without any moving optical device. Consequently, we study its cross-correlation function in a wavefront folding interferometer. The comparison with theoretical predictions yields excellent agreement.

Análisis fisicoquímico del MTA Angelus ® y Biodentine ® mediante difracción de rayos X, espectrometría de energía dispersiva, fluorescencia de rayos X, microscopio electrónico de barrido y espectroscopía de rayos infrarrojos / Physicochemical analysis of MTA Angelus ® and Biodentine ® conducted with X ray difraction, dispersive energy spectrometry, X ray fluorescence, scanning electron microscope and infra red spectroscopy

El propósito de este estudio fue caracterizar los componentes de los cementos comerciales para uso en odontología MTA Angelus ® Blanco (Angelus, Lodrina, Paraná Brasil) y de Biodentine TM (Septodont, Saint-Maur-des Fosses, Francia) mediante Microscopia Electrónica de Barrido, difracción de rayos X, fluorescencia de rayos X, espectrometría de dispersión de electrones y espectroscopia infrarroja. Los dos cementos se mezclaron según las indicaciones del fabricante. Se les practicó un estudio de textura de superficie mediante el microscopio electrónico de barrido (MEB), un análisis de difracción de rayos X (DRX), un análisis de fluorescencia de rayos X (FRX), un análisis de espectrometría de energía dispersiva (EDS) y un análisis de espectroscopia infrarroja (IR), para determinar los grupos funcionales. Resultados: Se presentó una diferencia en el análisis XRD entre Biodentine presentó Na2O y ZrO2 mientras que están ausentes en el MTA. El MTA presentó Cr2O3 y BiO2 ausentes en el Biodentine. En el análisis de EDS las diferencias fueron en el agente radiopacador y que el Biodentine presentó Cl a diferencia del MTA y en el análisis estadístico realizado, a pesar de que prácticamente se presentaron los mismos componentes, los porcentajes en los contenidos de éstos fueron estadísticamente signifi cativos. En el análisis de MEB hay una gran diferencia, el MTA presenta una superfi cie porosa e irregular, el Biodentine una forma fi brilar e irregular. Conclusión: Existe una gran similitud en los componentes químicos entre el MTA Angelus y Biodentine con excepción de los componentes químicos para proporcionarles radiopacidad, el tamaño y la forma del grano y en el caso del Biodentine el cloruro de calcio.

The aim of the present study was to characterize components of commercial cements used in dentistry MTA Angelus® White (Angelus Lodrina, Parana Brazil) and Biodentine TM (Septodont, Saint-Maurdes Fosses, France). Techniques used for said characterization were Scanning Electron Microscope, X-Ray Diffraction, X Ray Fluorescence, Electron Dispersion Spectrometry, and Infrared Spectroscopy. Both cements were mixed according to manufactures instructions. A study of surface texture was conducted with Scanning Electron Microscope (SEM), and X Ray Diffraction (XRD) analysis, and X Ray fluorescence analysis (XRF), an analysis of Dispersive Energy Spectrometry (DES), as well as an Infra Red Spectroscopy (IRS) in order to determine functional groups. Results: In XRD analysis, a difference was found: Biodentine exhibited Na2O and ZrO2. These elements were absent in MTA. MTA presented Cr2O3 and BiO2 which in turn were absent in Biodentine. EDS analysis revealed that differences were found in the radio-opacifying agent, and that Biodentine presented CaCl2 differing in this from MTA. Statistical analysis conducted revealed statistically signifi cant percentages in contents, even though components were found to be practically the same. SEM analysis revealed marked differences: MTA presented irregular and porous surface whereas Biodentine exhibited irregular and filament form. Conclusion: There is a great similarity in the chemical components of MTA Angelus and Biodentine, with the exception of chemical components providing radio-opacity, the size and form of the grain, and, in Biodentine presence of calcium chloride.

Quasi-one-dimensional optical lattices for soliton manipulation.

Based on angular spectrum engineering, we report the generation of optical lattices whose two-dimensional transverse nondiffracting pattern can be reduced to a quasi-one-dimensional intensity structure formed by either a single or multiple parallel channels. Remarkably, many features for each channel such as its maximum intensity, modulation, width, or separation among channels, can be controlled and modified in order to meet the requirements of particular applications. In particular, we demonstrate that these lattices can provide useful schemes for soliton routing and steering. We demonstrate the existence domain of ground-state solitons for the single quasi-one-dimensional lattice, and we show that these nondiffracting beams allow "push and pull" dynamics among the neighbor solitons propagated along the nondiffracting channels generated.

Similitud de la morfología y química elemental de los cementos tipo agregado de trióxido mineral y cemento Portland, mediante microscopia electrónica de barrido y espectroscopia de dispersión de electrones / Similarities of elemental chemistry and morphology of cements type mineral trioxide aggregate and Portland cement through the use of scanning electronic microscopy and electron dispersion spectroscopy

En la actualidad, los estudios acerca de la similitud entre el cemento Portland y los cementos tipo mineral de tri-oxi agregado han demostrado que estos compuestos presentan un desempeño análogo, ya que son elaborados con base en el cemento Portland. Con el objeto de verificar los componentes y porcentajes del cemento Portland y los cementos comerciales tipo agregado de trióxido mineral Pro-Root® blanco y Pro-Root® gris, Angelus® y CPM® se elaboraron cinco muestras de cada material de 8 x 4 mm y se les practicó un estudio de textura de superficie mediante microscopio electrónico de barrido y un análisis de espectrometría de energía dispersiva. Resultados: Los cementos mostraron gran similitud entre el cemento Portland y el agregado de trióxido mineral, sólo que en el agregado de trióxido mineral encontramos ausencia de Fe, Mg, Na y K, y en los cementos tipo agregado de trióxido mineral se encontró regularmente O, C, Si, Ca, Al, Cl y Bi; únicamente se detectó la presencia de Ba en el CPM®. Conclusiones: Encontramos gran similitud de los componentes químicos entre el cemento Portland y los cementos tipo agregado de trióxido mineral de todas las marcas comerciales.

Currently, studies on similarities among Portland cement and cements type mineral trioxide aggregate have shown that these compounds exhibit similar performance. This can be due to the fact that they are made based on Portland cement. With the aim of assessing percentages and components of Portland cement and commercial cements type mineral trioxide aggregate ProRoot® white and Pro-Root® grey, Angelus® and CPM®, five 8 x 4 mm samples of each material were processed. These samples were subjected to a study of surface texture. This study was conducted with the help of a scanning electron microscope as well as a energy dispersive spectrometry analysis. Results: Upon comparison, Portland cement and mineral trioxide aggregate cements showed great similarities. The main difference was than in mineral trioxide aggregate there was absence of Fe, Mg, Na and K; in mineral trioxide aggregate cements O, C, Si, Ca, Al, Cl and Bi were found regularly. Ba presence was only detected in CP®. Conclusions: The present study established the presence of great similarities among chemical components of Portland cement and mineral trioxide aggregate cements of all commercial brands.

Orbital angular momentum of optical vortices from power measurements and the cross-correlation function.

We show that the complex-amplitude cross-correlation function between two beams can be obtained by the global Stokes parameters. We apply this approach to determine the topological charge of a Laguerre-Gaussian (LG) beam by performing power measurements only. Additionally, we study the connection of the cross-correlation function with the degree of polarization for nonuniformly polarized beams, and we obtain closed-form expressions of the cross correlation for LG vector modes and the generalized full Poincaré beams.

Comparación del transporte radicular en conductos radiculares curvos utilizando las técnicas Twisted File(R) y Reciproc(R) / Evaluation of transportation incurved root canals using Reciproc(R) and TwistedFile(R) techniques

Objetivo: La preparación del conducto radicular con un solo instrumento con movimiento reciprocante está generando preocupación acerca de su comportamiento en la preparación de los conductos. El propósito de este estudio fue comparar qué sistema (TwistedFiles(R) oReciproc(R)) produce menos transporte radicular en conductos curvos. Metodología: Se utilizaron 40 molares inferiores humanos recién extraídos con curvaturas entre 25 y 35 grados, siguiendo la técnica de Schneider. Los molares fueron divididos aleatoriamente en dos grupos de 20 molares cada uno; Grupo 1: se prepararon usando movimiento de rotación continua con limas Twisted Files(R) mientras que en el Grupo 2 se prepararon con movimiento reciprocante con limas Reciproc(R). Se determinó el transporte del conducto radicular a través de CTScan midiendo la curvatura exterior e interior antes y después de la preparación. Resultados: En ambos grupos se encontró transporte del conducto radicular. Los resultados se analizaron mediante la prueba t de Student. No hubo diferencias significativas en los grados y las direcciones de transporte entre TF y grupos RP (p <.05). Conclusiones: La instrumentación con movimiento reciprocante no aumentó el transporte del conducto radicular cuando se comparacon el movimiento de rotación continua. El movimiento recíproco podría ser un método alternativo en la configuración del conducto radicular

Objective: The single-file root canal instrumentation technique using reciprocating motion is generating concern abou this behavior in root canals preparation. The purpose of this study was to compare which system Twisted Files(R) and Reciproc(R) produces less root transportation in curved root canal. Methodology: 40 extracted human mandibular molars with curvature between 25-35 degrees following Schneider’s technique. All teeth were randomly divided into 2 groups of 20 root canals each. Group 1 were prepared by using continuous rotation motion with Twisted File(R) Group 2 were prepared with reciprocating motion with Reciproc(R) files, the root canal transportation was determined through CT Scan measuring the external and internal curvature before and after preparation. Results: Both studied preparations systems created root canal transportation. The results were analysed by the t Student test. There were no significant differences in both the degrees and directions of transportation between TF and RP groups (P > .05). Conclusions: The reciprocating motion instrumentation did not increased root canal transportation when compared with continuous rotation motion. Reciprocating motion might be an alternative method in root canal shaping

Comparación in vitro de la actividad antimicrobiana de AhPlus, RSA y Ledermix contra Enterococcus faecalis / In vitro comparison of anti-microbial activity of AH Plus, RSA and Ledermix against Enterococcus faecalis

Objetivo: Evaluar in vitro la actividad antimicrobiana de dos selladores endodónticos RSA, AH Plus y de la pasta LedermixN sobre Enterococcus faecalis con tres diferentes técnicas. Método: Prueba de contacto directo. En una superficie de acrílico se colocó el sellador y se inoculó una suspensión de E. faecalis, se dejó en un microtubo con 1mL de caldo BHI, se realizaron diluciones logarítmicas sembrándose en placas de agar sangre para cuantificar las unidades formadoras de colonia. Prueba de dilución. Los selladores y la pasta se colocaron en un cilindro de plástico, la bacteria se inoculó en el caldo de cultivo y se realizó el mismo procedimiento de cuantificación. Prueba de dilución en agar. Se realizaron tres pozos en una placa de agar sangre y se rellenaron con los dos cementos, la pasta de LedermixN se inoculó una suspensión de E. faecalis en la superficie, para evaluar zonas de inhibición de crecimiento. Resultados: La pasta de Lesdermix N tuvo mayor porcentaje de actividad antimicrobiana en la prueba de contacto directo. Ningún cemento ni la pasta presentó actividad antimicrobiana en la prueba de dilución y en la prueba de dilución en agar; en ésta el sellador AH plus y la pasta LedermixN presentaron un halo de hemólisis en las placas de agar sangre. Conclusiones: La técnica de contacto directo es la más adecuada para evaluar el efecto antimicrobiano de los cementos.

Aim: In vitro assessment of antimicrobial activity sustained by two root canal sealers: RSA®, AH Plus® as well as LedermixN® paste upon Enterococcus faecalis using three different techniques. Method: Direct contact test (DCT). Sealers were placed on an acrylic surface. A E. faecalis suspension was inoculated and left in a microtube with 1 mL of BHI broth. Logarithmic dilutions were conducted spreading them in blood agar plates so as to quantify CFU's (colony forming units). Dilution test (DT). Sealers and paste were placed in a plastic cylinder. Bacteriae were inoculated in the culture broth and the same quantification procedure was undertaken. Agar dilution test (ADT). On a blood agar plate three wells were manufactured: they were filled with both cements. On the LedermixN paste surface a E. faecalis suspension was inoculated so as to assess growth inhibition areas. Results: In the Direct contact test, LedermixN paste showed higher antimicrobial activity percentage. Neither of both cements nor the paste presented antimicrobial activity in dilution and Agar dilution test. In the Agar dilution test, AH Plus sealer and LedermixN paste exhibited a hemolysis halo in the blood agar plates. Conclusions: Direct contact test technique was considered the most appropriate to assess antimicrobial effects of cements.

Evaluación de la citotoxicidad de distintos cementos selladores endodónticos en cultivos de fibroblastos gingivales / Citotoxicity assessment of different endodontic-use sealing cements in gingival fibroblast cultures

El objetivo de esta investigación fue evaluar in vitro la respuesta de fibroblastos gingivales contra diferentes selladores endodónticos mediante cultivos celulares, en un lapso de 96 horas. Los resultados obtenidos a intervalos de tiempo de 0, 1, 2, 3, 6, 24, 48, 72 y 96 horas fueron utilizados para determinar la citotoxicidad de los selladores. Cultivos de fibroblastos gingivales sin ningún sellador y con Sealapex fueron utilizados como controles positivos y negativos respectivamente. Los resultados fueron comparados con los controles negativos y analizados estadísticamente por medio de la prueba t Dunnett (p ≤ 0.05). Los cementos selladores investigados fueron: ProRoot MTA gris y blanco CPM, MTA Angelus, Sealapex y GuttaFlow. Los resultados demostraron que a pesar de que el ProRoot MTA (gris y blanco) MTA Angelus, CPM y GuttaFlow demostraron tener un potencial citotóxico menor que el Sealapex, no se encontraron diferencias estadísticas significativas.

The aim of the present study was the in vitro evaluation of the response, within 96 hours, of gingival fibroblast cultures with respect to different endodontic sealers. Results obtained at time intervals of 0, 1, 2, 3, 6, 24, 48, 72 and 96 hours were used to determine sealers' cytotoxicity. Gingival fibroblasts cultures without root canal sealer and with Sealapex were used as negative and positive controls respectively. Results were compared with negative controls and statistically analyzed with t Dunnett test (p ≤ 0.05). Assessed sealing cements were: ProRoot MTA, grey and white, CPM, MTA Angelus, Sealapex and GuttaFlow. Results showed that even though ProRoot MTA (grey and white) MTA Angelus, CPM and GuttaFlow exhibited lower cytotoxic potential than Sealapex, no statistical significant differences were established.

Focal shift in vector Mathieu-Gauss beams.

The three dimensional distribution of focused vector Mathieu-Gauss beams (vMG) is studied in the vicinity of the geometrical focus of an unapertured thin lens. We adopt two different intensity based criteria for defining the actual focus. Our analysis confirms the existence of a focal shift towards the lens for this type of beams. The dependence of the focal shift on the different parameters of the beams is discussed in detail. Beams with different states of polarization are studied as well, and it is shown that the focal shift is independent of the polarization.

Optical rankine vortex and anomalous circulation of light.

Rankine vortex characteristics of a partially coherent optical vortex are explored using classical and physical optics. Unlike a perfectly coherent vortex mode, the circulation is not quantized. Excess circulation is predicted owing to the wave nature of composite vortex fields. Based on these findings, we propose a vortex stellar interferometer.

Analysis of eigenfields in the axicon-based Bessel-Gauss resonator by the transfer-matrix method: comment.

Numerical calculations recently published [J. Opt. Soc. Am. A23, 912 (2006)] on the eigenmodes in axicon-based Bessel-Gauss resonators revealed significant inconsistencies regarding the modal patterns, the mode losses, the mode ordering by loss, and the intracavity field distributions. We show that the results are inaccurate mainly because (a) it was overlooked in the derivation of the matrix equations that light crosses twice through the axicon in a complete round-trip and (b) the numerical method used to evaluate the diffraction integral equations cannot resolve the eigenvalues and eigenfields for the given resonator configuration.