Near-infrared supercontinuum source by intracavity silica-based highly-nonlinear fiber

Near-infrared supercontinuum generation by using silica-based highly-nonlinear fiber placed inside of the ring-cavity of an erbium-doped fiber laser pulsed by mode-locking is experimentally demonstrated. Only one erbium-doped fiber amplifier is employed to generate supercontinuum with a spectral width as long as 830 nm (from 1205 to 2035 nm) and a spectral power higher than -30 dBm/nm. To generate supercontinuum, it is not necessary a second amplifier to raise the power of the laser pulses coupled into the nonlinear fiber. Moreover, all the devices employed are commercial and available at any photonics laboratory. To the best of our knowledge, this is the first demonstration of this kind of device by pumping the nonlinear fiber in the third window of communications

A new device for determining the compression after impact strength in thin laminates

In this work a new device has been developed to estimate compression-after-impact (CAI) strength. This device allows the testing of laminates thinner than those recommended by CAI test standards. The proposed device is composed of a support structure, with a set of vertical ribs that stabilize the specimen during the test, increasing the buckling load. A numerical analysis was made to ensure that global buckling does not occur in the laminate during the CAI test, and that there is no interference with the damage area. Laminate specimens were tested with the proposed device and the ASTM device. For specimens 4.416 mm thick (thickness according to ASTM D7137 standard), the test results were similar with both devices. For thinner laminates, higher CAI strength was estimated with the proposed device than with the ASTM device, showing that the global buckling was delayed.The authors are indebted to the Foundation for Research, Development and Application of Composite Materials (FIDAMC) and Innovation Works (EADS) for the financial support of this work (project Ilia). Also, the authors acknowledge the collaboration of the mechanical laboratories in FIDAMC and in Department of Continuum Mechanics and Structural Analysis of University Carlos III of Madrid.Publicad

Coherent artifact and time-dependent polarization in amplified ultrafast erbium-doped fibre lasers

Mode-locked erbium-doped fibre lasers are ultrashort pulsed sources widely studied due to their versatility and multiple applications in the near infrared range. Here we present the experimental study of the emission of a passive mode-locked erbium-doped fibre laser with an amplification stage outside the cavity by means of Frequency Resolved Optical Gating (FROG) and spectral interferometry. Due to shot-to-shot instabilities, the FROG traces can be understood as the combination of two different traces, corresponding to the coherent artifact and the average pulse characteristics. We have modified a Principal Components Generalized Projections Algorithm, in order to make it able to retrieve efficiently both the coherent artifact and the average pulse. In addition, we study the temporal dependence of the polarization, showing that the pulses present time-dependent polarization with a stable spectral relative phase between the horizontal and vertical projections. Up to our knowledge, this is the first experimental study that shows the FROG measurements of unstable pulse trains associated with the coherent artifact and analyses the time-dependent polarization in ultrafast fibre lasers

Simultaneous optimization of circadian and color performance for smart lighting systems design

We present in this work a method to design lighting sources that can be adapted to different temperatures of color and, simultaneously, with a tunable circadian character. We obtained an acceptable range of tuning in both parameters compared to the bibliography. This kind of lighting source has potential applications particularly in building lighting, but also in farming or agriculture. At the same time, we have shown the possibilities of multiobjective optimizations in the lighting industry. The optimization has been developed using the Genetic Algorithm and multiobjective merit functions. The lighting source is able to work under two different regimes regarding the circadian effect, with a design based on a combination of two monochromatic and two white Lighting Emitting Diodes (enough for controlling the circadian character and the color performance at the same time). A prototype, which can be manually or automatically controlled, has been also implemented and evaluated, with a performance in terms of color coordinates very close to the daylight, showing a modulation of the Circadian Efficacy of Radiation between 6% and 16%, and a Color Rendering Index above 80%

SARS-CoV-2 congenital infection and pre-eclampsia-like syndrome in dichorionic twins: A case report and review of the literature

Although the route of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is mainly respiratory, vertical transmission seems possible.1 We report the case of a woman with a dichorionic diamniotic twin pregnancy admitted to Hospital Clínico Universitario Lozano Blesa at 38+4 weeks of gestation due to severe pre-eclampsia in the context of a SARS-CoV-2 infection (positive nasopharyngeal PCR; Viasure, CerTest Biotec., Zaragoza, Spain) with a probable transplacental transmission of the virus to both twins..

Digital in-line holography with a spatially partially coherent beam

We propose in this paper an analytical solution to the problem of scalar diffraction of a partially coherent beam by an opaque disk. This analytical solution is applied in digital in-line holography of particles. We demonstrate that the reconstruction by means of fractional Fourier transformation is still possible when a spatially partially coherent beam is used. Numerical simulations and experiments have been carried out

Inflammation affects the viability and plasticity of equine mesenchymal stem cells: Possible implications in intra-articular treatments

Mesenchymal stem cells (MSCs) are gaining relevance for treating equine joint injuries because of their ability to limit inflammation and stimulate regeneration. Because inflammation activates MSC immunoregulatory function, proinflammatory priming could improve MSC efficacy. However, inflammatory molecules present in synovial fluid or added to the culture medium might have deleterious effects on MSCs. Therefore, this study was conducted to investigate the effects of inflammatory synovial fluid and proinflammatory cytokines priming on viability and plasticity of equine MSCs. Equine bone marrow derived MSCs (eBM-MSCs) from three animals were cultured for 72 h in media supplemented with: 20% inflammatory synovial fluid (SF); 50 ng/mL IFN-¿ and TNF-a (CK50); and 20 ng/mL IFN-¿ and TNF-a (CK20). Proliferation assay and expression of proliferation and apoptosis-related genes showed that SF exposed-eBM-MSCs maintained their viability, whereas the viability of CK primed-eBM-MSCs was significantly impaired. Tri-lineage differentiation assay revealed that exposure to inflammatory synovial fluid did not alter eBM-MSCs differentiation potential; however, eBM-MSCs primed with cytokines did not display osteogenic, adipogenic or chondrogenic phenotype. The inflammatory synovial environment is well tolerated by eBM-MSCs, whereas cytokine priming negatively affects the viability and differentiation abilities of eBM-MSCs, which might limit their in vivo efficacy

Single-shot d-scan technique for ultrashort laser pulse characterization using transverse second-harmonic generation in random nonlinear crystals

We demonstrate a novel dispersion-scan (d-scan) scheme for single-shot temporal characterization of ultrashort laser pulses. The novelty of this method relies on the use of a highly dispersive crystal featuring antiparallel nonlinear domains with a random distribution and size. This crystal, capable of generating a transverse second-harmonic signal, acts simultaneously as the dispersive element and the nonlinear medium of the d-scan device. The resulting in-line architecture makes the technique very simple and robust, allowing the acquisition of single-shot d-scan traces in real time. The retrieved pulses are in very good agreement with independent frequency-resolved optical grating measurements. We also apply the new single-shot d-scan to a terawatt-class laser equipped with a programmable pulse shaper, obtaining an excellent agreement between the applied and the d-scan retrieved dispersions

Ultrastructural, cytogenetic, and molecular findings in mast cell leukemia : Case report

We report a de novo aleukemic form of MCL with a complex monosomic karyotype with LOH for multiple chromosomes and TP53 mutation. Additionally, whereas D816V KIT was not found, the c-Kit transmembrane domain p.M541L variant was detected which is the most common SNP of KIT gene in humans with controversial pathogenic role. In these cases, it is crucial to perform a rapid broad molecular study for an accurate diagnosis which could help to initiate targeted therapy