Role of stromal Caveolin-1 (CAV1) levels in breast cancer angiogenesis

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Bioquímica. Fecha de lectura: 19-10-2018Tumors have been described as “wounds that never heal”; and non-tumoral surrounding cell populations involved in angiogenesis and response to injury, such as endothelial cells, immune cells and fibroblasts are actively engaged to support the aberrant growth and remodeling of the tumor mass, which conversely determine tumor architecture and behavior. These cells, along with extracellular matrix (ECM) components, define the tumor microenvironment or tumor stroma. While breast cancer progression was conceived for a long time to be largely dependent on aberrant mutations in tumor cells, stromal Cancer-Associated Fibroblasts (CAFs) have been demonstrated to modulate breast cancer growth, invasion, metastasis and therapeutic resistance. Caveolin-1 (CAV1), a prominent organizer of plasma membrane properties and function, exhibits extensive ties with many events defining tumor onset and progression. Although previous studies have shown CAV1 expression levels in CAFs to influence breast cancer growth and metastasis, the underlying driving mechanisms remain incompletely characterized. In this regard, ECM modification and metabolic reprogramming have been proposed as key aspects of a stromal CAV1-dependent role in tumor biology. This thesis research report aims to contribute to our understanding as to how CAV1 expression in stromal CAFs impact tumor angiogenesis, and thus tumor hypoxia, cancer aggressiveness and metastasis. The present work showcases evidence supporting a positive reciprocal feedback relationship between stromal CAV1 downregulation and endoplasmic reticulum (ER) stress, which can drive exacerbated proangiogenic signaling, causative of the generation of an aberrant and dysfunctional tumor vasculature. This report proposes defective angiogenesis and consequent hypoxia as major driving causes for increased aggressiveness of breast cancer in low stromal CAV1 tumors

Influence of different stabilization systems and multiple ultraviolet A (UVA) aging/recycling steps on physicochemical, mechanical, colorimetric, and thermal-oxidative properties of ABS

Commercially mass-polymerized acrylonitrile–butadiene–styrene (ABS) polymers, pristine or modified by stabilization systems, have been injection molded and repeatedly exposed to ultravilolet A (UVA) radiation, mechanical recycling, and extra injection molding steps to study the impact of such treatments on the physicochemical, mechanical, colorimetric, and thermal-oxidative characteristics. The work focus on mimicking the effect of solar radiation behind a window glass as relevant during the lifetime of ABS polymers incorporated in electrical and electronic equipment, and interior automotive parts by using UVA technique. The accelerated aging promotes degradation and embrittlement of the surface exposed to radiation and causes physical aging, deteriorating mechanical properties, with an expressive reduction of impact strength (unnotched: up to 900%; notched: up to 250%) and strain at break (>1000%), as well as an increase in the yellowing index (e.g., 600%). UV-exposition promotes a slight increase in the tensile modulus (e.g., 10%). The addition of antioxidants (AOs) leads to a limited stabilization during the first UVA aging, although the proper AO formulation increases the thermal-oxidative resistance during all the cycles. Mechanical recycling promotes an increase in strain at break and unnotched impact strength alongside a slight decrease in tensile modulus, due to disruption of the brittle surface and elimination of the physical aging

Influence of Different Stabilization Systems and Multiple Ultraviolet A (UVA) Aging/Recycling Steps on Physicochemical, Mechanical, Colorimetric, and Thermal-Oxidative Properties of ABS

Commercially mass-polymerized acrylonitrile–butadiene–styrene (ABS) polymers, pristine or modified by stabilization systems, have been injection molded and repeatedly exposed to ultraviolet A (UVA) radiation, mechanical recycling, and extra injection molding steps to study the impact of such treatments on the physicochemical, mechanical, colorimetric, and thermal-oxidative characteristics. The work focus on mimicking the effect of solar radiation behind a window glass as relevant during the lifetime of ABS polymers incorporated in electrical and electronic equipment, and interior automotive parts by using UVA technique. The accelerated aging promotes degradation and embrittlement of the surface exposed to radiation and causes physical aging, deteriorating mechanical properties, with an expressive reduction of impact strength (unnotched: up to 900%; notched: up to 250%) and strain at break (>1000%), as well as an increase in the yellowing index (e.g., 600%). UV-exposition promotes a slight increase in the tensile modulus (e.g., 10%). The addition of antioxidants (AOs) leads to a limited stabilization during the first UVA aging, although the proper AO formulation increases the thermal-oxidative resistance during all the cycles. Mechanical recycling promotes an increase in strain at break and unnotched impact strength alongside a slight decrease in tensile modulus, due to disruption of the brittle surface and elimination of the physical aging.This research was funded by the European Union’s Horizon 2020 Research and Innovation Program, grant number 730308

Forward Brillouin Scattering Spectroscopy in Optical Fibers with Whispering-Gallery Modes

Opto-mechanical interactions in different photonic platforms as optical fibers and optical microresonators are raising great attention, and new exciting achievements have been reported in the last few years. Transverse acoustic mode resonances (TAMRs) in optical fibers -which can be excited optically via electrostriction and generate forward Brillouin scattering (FBS)- are being promoted as the physical mechanism for new fiber-sensing concepts. Here, the study reports a novel approach to detect and characterize opto-excited TAMRs of an optical fiber based on the interplay with optical surface wave resonances, i.e., optical whispering-gallery mode (WGM) resonances. TAMRs induce perturbations in the geometry and the dielectric permittivity of the fiber over the entire cross-section. It is shown that these perturbations couple the acoustic with the optical resonances and affect WGMs in a noticeable way. The study proposes and demonstrates the use of WGMs for probing opto-excited TAMRs in optical fibers. This probing technique provides the narrowest linewidths ever reported for the TAMRs and demonstrates an optimum efficiency for the detection of low-order TAMRs. The interplay between sensitivity, bandwidth, and Q factor of the WGM resonance is discussed

Strain and temperature measurement discrimination with forward Brillouin scattering in optical fibers

A novel method that enables simultaneous and discriminative measurement of strain and temperature using one single optical fiber is presented. The method is based on the properties of transverse acoustic mode resonances (TAMRs) of the optical fiber. In particular, it is based on the different sensitivity to temperature and strain that exhibit the radial modes R(0,m) and a family of torsional-radial modes denoted as TR(1)(2,m). We show that the resonance frequencies of both types of resonances shift linearly with temperature and strain, but at different rates. By the combined use of the different sensitivities of the two families of TAMRs, we experimentally demonstrate discriminative measurements of strain and temperature. A detection limit of strain and temperature better than 25 με and 0.2 °C is achieved

High accuracy measurement of Poisson's ratio of optical fibers and its temperature dependence using forward-stimulated Brillouin scattering

Transverse acoustic mode resonances enable a high accuracy determination of Poisson's ratio and elastic properties of optical fibers. An all-optical pump and probe technique is used for efficient excitation and accurate characterization of both, radial and torsional-radial acoustic resonances of optical fibers. Simple and precise algebraic expressions for the frequencies of high order acoustic resonances are derived, enabling a rigorous analysis of the experimental data using standard least squares fitting. Following this approach, the determination of Poisson's ratio does not require the measurement of any physical length, but only frequency measurements are required. An accuracy better than 1 is achieved. The dependence of the fiber Poisson's ratio with temperature is also determined experimentally

Recent advances in Forward Brillouin Scattering: Sensor applications

In-fiber opto-mechanics based on forward Brillouin scattering has received increasing attention because it enables sensing the surrounding of the optical fiber. Optical fiber transverse acoustic resonances are sensitive to both the inner properties of the optical fiber and the external medium. A particularly efficient pump and probe technique¿assisted by a fiber grating¿can be exploited for the development of point sensors of only a few centimeters in length. When measuring the acoustic resonances, this technique provides the narrowest reported linewidths and a signal-tonoise ratio better than 40 dB. The longitudinal and transverse acoustic velocities¿normalized with the fiber radius¿can be determined with a relative error lower than 10−4, exploiting the derivation of accurate asymptotic expressions for the resonant frequencies. Using this technique, the Poisson's ratio of an optical fiber and its temperature dependence have been measured, reducing the relative error by a factor of 100 with respect to previously reported values. Using a single-point sensor, discriminative measurements of strain and temperature can be performed, achieving detection limits of ±25 με and ±0.2 °C. These results show the potential of this approach for the development of point sensors, which can be easily wavelength-multiplexed

Characterization of Leptoglossus occidentalis eggs and egg glue

Producción CientíficaSimple Summary: This study explored the chemical components of the egg glue used by the Western Conifer Seed Bug (Leptoglossus occidentalis Heidemann, 1910) to agglutinate eggs and adhere to pine needles. Results showed that the adhesive secretion includes plasticizers and thermoplastic elastomer resins with semiochemical properties in an oily matrix containing proteins. This knowledge of the egg glue composition can be used to develop new control strategies for L. occidentalis, potentially limiting the economic impact caused by this pest insect that reduces the production of pine nuts by up to 25%.The western conifer seed bug (Leptoglossus occidentalis Heidemann, 1910, Heteroptera: Coreidae) has a significant economic impact due to the reduction in the quality and viability of conifer seed crops; it can feed on up to 40 different species of conifers, showing a clear predilection for Pinus pinea L. in Europe. Its incidence is especially relevant for the pine nut-producing industry, given that the action of this pest insect can reduce the production of pine nuts by up to 25%. As part of ongoing efforts aimed at the design of control strategies for this insect, this work focuses on the characterization (by scanning electron microscopy–energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and gas chromatography–mass spectroscopy, GC–MS) of the compounds released by these insects during oviposition, with emphasis on the adhesive secretion that holds L. occidentalis eggs together. Elemental analysis pointed to the presence of significant amounts of compounds with high nitrogen content. Functional groups identified by infrared spectroscopy were compatible with the presence of chitin, scleroproteins, LNSP-like and gelatin proteins, shellac wax analogs, and policosanol. Regarding the chemical species identified by GC–MS, eggs and glue hydromethanolic extracts shared constituents such as butyl citrate, dibutyl itaconate, tributyl aconitate, oleic acid, oleamide, erucamide, and palmitic acid, while eggs also showed stearic and linoleic acid-related compounds. Knowledge of this composition may allow advances in new strategies to address the problem caused by L. occidentalis.Unión Europea, LIFE MycoRestore - (project LIFE18 CCA/ES/001110

Operational use of SEVIRI and other satellite enhancements at AEMET

Presentación realizada en: 3rd ACCORD ASW celebrado del 27 al 31 de marzo de 2023 en Tallin, Estonia

Low-repetition-rate all-polarization maintaining thulium-doped passively modelocked fiber laser

We have developed a passively mode-locked, all-polarization maintaining, low-repetition-rate thulium-doped fiber laser (PM TDFL) emitting at 1951 nm and pumped by an erbium-ytterbium-doped all-fiber laser at 1561 nm. The PM TDFL was developed with a 44.67 m long polarization-maintaining all-fiber resonator Fabry-Perot using a semiconductor saturable absorber mirror at one end and a highly reflective fiber Bragg grating at the other. In this way, transform-limited low-repetition-rate light pulses at 2.3 MHz were generated, with each light pulse having a temporal width of 81 ps, and a spectral width of 50 pm. We have also compared the performance of this laser with a shortened version of this cavity, 6.25 m long, emitting at 15.6 MHz