Mechanical and morphological responses of osteoblast-like cells to two-photon polymerized microgrooved surfaces.

Microgrooved surfaces are recognized as an important strategy of tissue engineering to promote the alignment of bone cells. In this work, we have investigated the mechanical and morphological aspects of osteoblasts cells after interaction with different micro-structured polymeric surfaces. Femtosecond laser writing technique was used for the construction of circular and parallel microgrooved patterns in biocompatible polymeric surfaces based on pentaerythritol triacrylate.

Urea in Dermatology: A Review of its Emollient, Moisturizing, Keratolytic, Skin Barrier Enhancing and Antimicrobial Properties.

Urea is a hygroscopic molecule (capable of absorbing water) present in the epidermis as a component of the natural moisturizing factor (NMF) and is essential for the adequate hydration and integrity of the stratum corneum. Urea improves skin barrier function including antimicrobial defense by regulating gene expression in keratinocytes relevant for their differentiation and antimicrobial peptide production. It also plays a fundamental role in regulating keratinocyte proliferation.

Speckle filtering through nonlinear wave mixing.

Light scattering by disordered media is a ubiquitous effect. After passing through them, the light acquires a random phase, masking or destroying associated information. Filtering this random phase is of paramount importance to many applications, such as sensing, imaging, and optical communication, to cite a few, and it is commonly achieved through computationally extensive post-processing using statistical correlation.

Kinetics of thermal degradation and lifetime study of poly(vinylidene fluoride) (PVDF) subjected to bioethanol fuel accelerated aging.

PVDF was prepared by compression molding, and its phase content/structure was assessed by WAXD, DSC, and FTIR-ATR spectroscopy. Next, PVDF samples were aged in bioethanol fuel at 60 °C or annealed in the same temperature by 30 ─ 180 days. Then, the influence of aging/annealing on thermal stability, thermal degradation kinetics, and lifetime of the PVDF was investigated by thermogravimetric analysis (TGA/DTG), as well as the structure was again examined.

Suitable state bases for nonlinear optical mode conversion protocols.

By considering parity-defined Laguerre-Gaussian (LG) and Hermite-Gaussian (HG) beams as input modes, we present arguments through experimental and theoretical results in order to affirm that using HG modes as bases is more suitable for optical mode conversion than using LG modes. By analyzing the normalized overlap integral and the generated modes, we determine a clear rule for the dominant mode for nonlinear mixing of HG beams, while the same is not possible for LG beams. In addition, examples of optical modal conversion using both HG and LG modes as input beams are demonstrated.

Measuring the topological charge of coherence vortices through the geometry of the far-field cross-correlation function.

Determination of orbital angular momentum of optical vortex beams has attracted the attention of many researchers over the last few years. For some applications, it is convenient to use a partially coherent vortex beam because of its robustness. In this work, we developed a method to measure the topological charge of a partially coherent vortex beam.

Sorting of spatially incoherent optical vortex modes.

Coherent optical vortices have promising applications in quantum and classical optical communication. They add new degrees of freedom to code information. In this context, to implement a tool enabling sorting of spatially multiplexed vortex states is fundamental.

Method to define non-diffracting optical beams mimicking the shape of simple plane curves.

We theoretically and experimentally demonstrate a method to define non-diffracting beams with different geometries. Our findings constitute an alternative to current methods for finding non-diffracting beams, which rely on the solution of the wave equation in a given coordinate system that has a limited number of possibilities or uses a complicated and time-consuming optimization algorithm. Therefore, the method is easier to follow, because it does not require optimization and allows one to obtain non-diffracting beams mimicking the geometry of simple plane curves.

An Improved Skin Lesion Matching Scheme in Total Body Photography.

Total body photography is used for early detection of malignant melanoma, primarily as a means of temporal skin surface monitoring. In a prior work, we presented a scanner with a set of algorithms to map and detect changes in pigmented skin lesions, thus demonstrating that it is possible to fully automate the process of total body image acquisition and processing. The key procedure in these algorithms is skin lesion matching that determines whether two images depict the same real lesion.

Talbot effect with partially coherent interfering Bessel beams.

We studied the free-space propagation of interfering partially coherent Bessel beams. The partially coherent superimposed Bessel beams were generated by diffracting a spatially incoherent light by two concentric circular slits. We observed a Talbot effect in the random intensity pattern and in the intensity correlation.

Direct Measurement of the Topological Charge in Elliptical Beams Using Diffraction by a Triangular Aperture.

We introduce a simple method to characterize the topological charge associated with the orbital angular momentum of a m-order elliptic light beam. This method consists in the observation of the far field pattern of the beam carrying orbital angular momentum, diffracted from a triangular aperture. We show numerically and experimentally, for Mathieu, Ince-Gaussian, and vortex Hermite-Gaussian beams, that only isosceles triangular apertures allow us to determine in a precise and direct way, the magnitude m of the order and the number and sign of unitary topological charges of isolated vortices inside the core of these beams.

Three-Dimensional Speckle Light Self-Healing-Based Imaging System.

Recently new methodologies for imaging have been achieved making use of multiple light scattering. Here we present the self-healing effect using a speckled light field. We present an experiment that constitutes a useful application for a three-dimensional light sheet-based imaging system through an inhomogeneous medium.

Talbot effect in optical lattices with topological charge.

We studied the interference resulting from the superposition of optical lattices, which are non-diffracting fields propagating in free space, and showed a Talbot self-imaging effect. These lattices are formed by spatially Fourier transforming a "quasi"-orbital angular momentum (OAM) state. We experimentally observed that although the Talbot images change, the Talbot length is insensitive to the topological charge of the "quasi"-OAM state.

Robustness of a coherence vortex.

We study, experimentally and theoretically, the behavior of a coherence vortex after its transmission through obstacles. Notably, we find that such a vortex survives and preserves its effective topological charge. Despite suffering changes on the modulus of the coherence function, these changes disappear during propagation.

Characterizing coherence vortices through geometry.

We produce coherence vortices experimentally and numerically due to the orbital angular momentum of light beams and study the dependence of their bright ring area and dark region on their different orders. This is a linear dependence with a slope proportional to the bright ring area or dark area. We show that it is possible to estimate any order of coherence vortices, including fractional orders, just by calculating the bright ring area or dark area of the vortices for some specific parameters of the incident beam.

Self-reconfiguration of a speckle pattern.

It is well known that coherent Bessel beam, a nondiffracting class of beam, possesses the ability of self-reconstructing or self-healing in the presence of obstacles. Here, we generated partially coherent Bessel and Gaussian beams using a spatial light modulator and studied the speckle pattern intensity in propagation after some speckles were blocked. We demonstrated that these partially coherent beams are unexpectedly robust against scattering by objects, overcoming the coherent Bessel beam and remaining independent of any special class of partially coherent beams.

Unveiling square and triangular optical lattices: a comparative study.

We study square and triangular optical lattice formation using a diffraction technique with light-possessing orbital angular momentum (OAM). We demonstrate that it is possible to use Fraunhofer diffraction of light by a square aperture to unveil OAM about two times bigger than would be possible with a triangular aperture. We notice that the pattern remains truncated until a topological charge (TC) equal to 20 with good precision.

Study of the birth of a vortex at Fraunhofer zone.

We analytically and experimentally study the Fraunhofer diffraction of an optical vortex beam possessing noninteger values of the azimuthal index. We show that the Fraunhofer diffraction of this beam presents the birth of a vortex at α=n+ε, where n is an integer number and ε is a small fraction. We discuss this behavior on the basis of the born vortex movement from a position of low intensity to high intensity when α is increased of an integer number in fractional steps of ε.

Strong correlations between incoherent vortices.

We establish a correlation rule of which the value of the topological charge obtained in intensity correlation between two coherence vortices is such that this value is bounded by the topological charge of each coherence vortex. The original phase information is scrambled in each speckle pattern and unveiled using numerical intensity correlation. According to this rule, it is also possible to obtain a coherence vortex stable, an integer vortex, even when each incoherent vortex beam is instable, non-integer vortex.

Engineering a square truncated lattice with light's orbital angular momentum.

We engineer an intensity square lattice using the Fraunhofer diffraction of a Laguerre-Gauss beam by a square aperture. We verify numerically and experimentally that a perfect optical intensity lattice takes place only for even values of the topological charge. We explain the origin of this behavior based on the decomposition of the patterns.

Fraunhofer diffraction of light with orbital angular momentum by a slit.

We study the Fraunhofer diffraction problem while taking into account the orbital angular momentum of light. In this case, the phase singularity of the light beam is incident on the slit in two different cases: in one, it is incident slightly above the slit, and in the other it is centered on the slit. We observed that the symmetry and the fringe formation in the interference pattern strongly depend on the amount of orbital angular momentum and the slit position in relation to the beam.

[Prebiotic inulin/oligofructose in Yacón root (Smallanthus sonchifolius), phytochemistry and standardization as basis for clinical and pre-clinical research].

Introduction: Experiments have demonstrated that the association between inulin and oligofructose can prevent colitis by modifying the intestinal microflora by acting as a prebiotic. It has also been found that this association is naturally present in the roots of the Yacón root (Smallanthus sonchifolius) making phytochemical and standardization studies well worth pursuing. These studies could contribute to the safe use of improved strains of Yacón, to significant savings in health resources, and to promoting additional clinical and pre-clinical research.