Dual regimes of ion migration in high repetition rate femtosecond laser inscribed waveguides

Ion migration in high repetition rate femtosecond laser inscribed waveguides is currently being reported in different optical glasses. For the first time we discuss and experimentally demonstrate the presence of two regimes of ion migration found in laser written waveguides. Regime-I, corresponds to the initial waveguide formation mainly via light element migration (in our case atomic weight < 31u), whereas regime-II majorly corresponds to the movement of heavy elements. This behavior brings attention to a problem which has never been analyzed before and that affects laser written active waveguides in which active ions migrate changing their local spectroscopic properties. The migration of active ions may in fact detune the pre-designed optimal values of active photonic devices. This paper experimentally evidences this problem and provides solutions to avert it.Comment: 4 pages, 5 figure

Polarized micro-Raman studies of femtosecond laser written stress-induced optical waveguides in diamond

Understanding the physical mechanisms of the refractive index modulation induced by femtosecond laser writing is crucial for tailoring the properties of the resulting optical waveguides. In this work we apply polarized Raman spectroscopy to study the origin of stress-induced waveguides in diamond, produced by femtosecond laser writing. The change in the refractive index induced by the femtosecond laser in the crystal is derived from the measured stress in the waveguides. The results help to explain the waveguide polarization sensitive guiding mechanism, as well as providing a technique for their optimization.Comment: 5 pages, 4 figure

Wearable Postural Control System for Low Back Pain Therapy

© 2021 IEEE. This version of the article has been accepted for publication, after peer review. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The Version of Record is available online at: https://doi.org/10.1109/10.1109/TIM.2021.3057935[Abstract]: Treatment of low back pain usually includes exercise, analgesics, prostheses, and, in severe cases, surgery. Early treatments based on postural control are essential to prevent low back pain and mitigate permanent damage. We present a wearable device, with an estimated cost below U.S. $100, which uses inertial units with triaxial accelerometers, gyroscopes, and magnetometers to measure the orientation of three sections of the spine. The device integrates the absolute and relative orientation from the sensors to estimate the posture of the back in real-time and uses a fuzzy system to control a vibration unit that indicates the user when to correct the posture of the back. We validated the device in controlled conditions, obtaining an rms deviation ≤1.24° and conducted a preliminary clinical pilot study with patients afflicted by lumbar hyperlordosis or lumbar hypolordosis. We observed an improved postural control and a reduction of low back pain in all cases. These results show a promising potential of the device to reduce pain, improve postural therapies, and raise postural awareness in patients affected with low back pain

Integrated waveguides and deterministically positioned nitrogen vacancy centers in diamond created by femtosecond laser writing

Diamond's nitrogen vacancy (NV) center is an optically active defect with long spin coherence times, showing great potential for both efficient nanoscale magnetometry and quantum information processing schemes. Recently, both the formation of buried 3D optical waveguides and high quality single NVs in diamond were demonstrated using the versatile femtosecond laser-writing technique. However, until now, combining these technologies has been an outstanding challenge. In this work, we fabricate laser written photonic waveguides in quantum grade diamond which are aligned to within micron resolution to single laser-written NVs, enabling an integrated platform providing deterministically positioned waveguide-coupled NVs. This fabrication technology opens the way towards on-chip optical routing of single photons between NVs and optically integrated spin-based sensing

Mad2 overexpression promotes aneuploidy and tumorigenesis in mice

Mad2 is an essential component of the spindle checkpoint that blocks activation of Separase and dissolution of sister chromatids until microtubule attachment to kinetochores is complete. We show here that overexpression of Mad2 in transgenic mice leads to a wide variety of neoplasias, appearance of broken chromosomes, anaphase bridges, and whole-chromosome gains and losses, as well as acceleration of myc-induced lymphomagenesis. Moreover, continued overexpression of Mad2 is not required for tumor maintenance, unlike the majority of oncogenes studied to date. These results demonstrate that transient Mad2 overexpression and chromosome instability can be an important stimulus in the initiation and progression of different cancer subtypes

Meropenem heteroresistance in clinical isolates of OXA-48–producing Klebsiella pneumoniae

OXA-48–producing Klebsiella pneumoniae isolates often show growth of colonies within inhibition zones in carbapenem diffusion assays. The nature of these colonies was investigated in a series of clinical isolates of OXA-48–producing K. pneumoniae obtained in the context of a hospital outbreak, and they were found to be persistent colonies that reproduced again the same phenotype when they were collected and tested in diffusion assays again. The frequency of mutations conferring resistance to meropenem (8 µg/mL) was determined for the same isolates. The average mutation frequency was 5.47·10-6 (range: 2.59·10-8–5.87·10-5), and the analysis of several resistant mutants showed that all of them had mutations in the ompK36 porin gene. Heteroresistance was investigated using population analysis profiling. The profiles were compatible with mutation frequency assays, and all the colonies analyzed were resistant mutants. In OXA-48–producing K. pneumoniae, the growth of persisters seems to be specific of diffusion assays

The use of banquettes of Posidonia oceanica as a source of fiber and minerals in ruminant nutrition. An observational study

In the search for new food sources that contribute to the optimization of livestock production this paper discusses the possibility of using waste (called banquettes) of a marine plant commonly found on the Mediterranean coasts: Posidonia oceanica. The idea stems from the use of a waste that in summertime generates large costs because it is considered bothersome on the beaches. Thus, tons and tons of residues are collected each year from the beach, being destined for incineration. However, alternative uses for these residues are suggested, such as forage that is particularly relevant for the Mediterranean coast, where the weather does not support abundant grass growth. With this purpose, samples of banquettes of P. oceanica from six different points of a touristic place located in the Murcia Region (S.E. of Spain) were collected in April 2012 on the same day directly from the beach above the water line, washed with distilled water and sun-dried for 48 h. Approximately 500 g of each sample of plant material was chopped and two subsamples of 200 g each were placed in airtight plastic containers and sent to the laboratory for mineral and chemical analysis. This report provides data on the nutritional composition of P. oceanica such as mineral contents (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and chemical composition (ash, CP, ether extract (EE), NDF and ADF, respectively) and ADL. Finally, the in sacco rumen disappearance of dry matter (DM), organic matter (OM), CP and NDF were studied. Our results showed that minerals, except for Fe, where within the range of values reported for P. oceanica in other parts of the Mediterranean region. Given the high Fe content further studies assessing the antagonic Fe–Cu interaction and its effect on animal health should be addressed. In relation to chemical composition, it is clear that this seagrass is a poor protein source and has levels of DM degradability at 24 h, similar to those obtained for cereal straw. The information summarized here shows some potential for the use of banquettes of P. oceanica as forage source in ruminant nutritionFunds for thefinancial support received for carryingout this work, through the project: Subproductos marinos ennutrición animal: utilidad de los arribazones deP. oceanicacomo fuente defibra en ganado caprino de leche (Ref. 15.271)S

Galaxy and mass assembly (GAMA): The environmental impact on SFR and metallicity in galaxy groups

We present a study of the relationships and environmental dependencies between stellar mass, star formation rate, and gas metallicity for more than 700 galaxies in groups up to redshift 0.35 from the Galaxy And Mass Assembly (GAMA) survey. To identify the main drivers, our sample was analysed as a function of group-centric distance, projected galaxy number density, and stellar mass. By using control samples of more than 16 000 star-forming field galaxies and volume-limited samples, we find that the highest enhancement in SFR (0.3 dex) occurs in galaxies with the lowest local density. In contrast to previous work, our data show small enhancements of ∼0.1 dex in SFR for galaxies at the highest local densities or group-centric distances. Our data indicates quenching in SFR only for massive galaxies, suggesting that stellar mass might be the main driver of quenching processes for star forming galaxies. We can discard a morphological driven quenching, since the Sérsic index distribution for group and control galaxies are similar. The gas metallicity does not vary drastically. It increases ∼0.08 dex for galaxies at the highest local densities, and decreases for galaxies at the highest group-centric distances, in agreement with previous work. Altogether, the local density, rather than group-centric distance, shows the stronger impact in enhancing both, the SFR and gas metallicity. We applied the same methodology to galaxies from the IllustrisTNG simulations, and although we were able to reproduce the general observational trends, the differences between group and control samples only partially agree with the observations

Galaxy and mass assembly (GAMA): The environmental impact on SFR and metallicity in galaxy groups

We present a study of the relationships and environmental dependencies between stellar mass, star formation rate, and gas metallicity for more than 700 galaxies in groups up to redshift 0.35 from the Galaxy And Mass Assembly (GAMA) survey. To identify the main drivers, our sample was analysed as a function of group-centric distance, projected galaxy number density, and stellar mass. By using control samples of more than 16 000 star-forming field galaxies and volume-limited samples, we find that the highest enhancement in SFR (0.3 dex) occurs in galaxies with the lowest local density. In contrast to previous work, our data show small enhancements of ∼0.1 dex in SFR for galaxies at the highest local densities or group-centric distances. Our data indicates quenching in SFR only for massive galaxies, suggesting that stellar mass might be the main driver of quenching processes for star forming galaxies. We can discard a morphological driven quenching, since the Sérsic index distribution for group and control galaxies are similar. The gas metallicity does not vary drastically. It increases ∼0.08 dex for galaxies at the highest local densities, and decreases for galaxies at the highest group-centric distances, in agreement with previous work. Altogether, the local density, rather than group-centric distance, shows the stronger impact in enhancing both, the SFR and gas metallicity. We applied the same methodology to galaxies from the IllustrisTNG simulations, and although we were able to reproduce the general observational trends, the differences between group and control samples only partially agree with the observations

Chromium Oxide Formation on Nanosecond and Femtosecond Laser Irradiated Thin Chromium Films

Thin coatings of Chromium oxide have been used for applications as absorbing material in solar cells, as protections for magnetic data recording devices and as shields in flexible solar cells. Thin coatings of pure chromium were vacuum deposited on a glass substrate using hot electrons from tungsten filament. These coatings were then treated with a nanosecond and femtosecond laser in ambient conditions. The microstructure, morphology and the color of the coatings treated with laser sources were modified and there was a formation of an oxide layer due to the heat dissipation on the chromium coating from the energetic photons. High-resolution scanning electron microscope studies showed the morphological evolution that are directly correlated with the laser fluence of both the nanosecond and femtosecond lasers. This morphological evolution was accompanied by the microstructural change as observed from the x-ray diffraction patterns, the chromaticity response of the coating was studied by UV-Vis spectrometer and the response of the coating in the visible region evolved with the laser fluences. The Rutherford backscattering depth profiling of the laser treated coatings revealed the diffusion of oxygen atoms in the coating as a result of laser treatment fluence