38 research outputs found

    Mode Converter and Multiplexer with a Subwavelength Phase Shifter for Extended Broadband Operation

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    4 pags., 3 figs., 1 tab.On-chip mode converters and multiplexers are fundamental components to scale the capacity of silicon optical interconnects by using different spatial modes of waveguides. Recently, we proposed a low loss and compact mode converter and multiplexer consisting of a subwavelength-engineered multimode interference coupler, tapered waveguides as phase shifter and a symmetric Y-junction. However, the narrow spectral response of the tapered phase shifter limited the device crosstalk performance. In this work, we demonstrate that the use of a subwavelength grating phase shifter with low phase-shift errors substantially reduces the crosstalk and expands the operational bandwidth. A complete multiplexer-demultiplexer link consisting of two devices in back-to-back configuration was fabricated in a 220-nm silicon-on-insulator platform. Experimental measurements of the complete link show insertion loss below 2 dB and crosstalk less than -17 dB over a bandwidth of 245 nm (1427 - 1672 nm).is work was supported in part by the Spanish Ministry of Science and Innovation (MICINN) under grants RTI2018- 097957-B-C33, RED2018-102768-T, TEC2015-71127-C2-1-R (FPI BES- 2016-077798) and NEOTEC-CDTI-SNEO20181232 (Alcyon Photonics S.L.); and the Community of Madrid – FEDER funds (S2018/NMT-4326). This project has received funding from the Horizon 2020 research and innovation program under Marie Sklodowska-Curie grant No. 73433

    La controversia sobre la recesión mundial, 2007-2014 : el capitalismo neoliberal en su fase de debacle

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    El objetivo principal de este libro es recopilar opiniones, datos y fundamentos de la crisis del capitalismo que se iniciara en el 2007, y que para el 2013 presenta características severamente graves. La crisis de la eurozona manifestada en históricas tasas de desempleo, desinversión y endeudamiento de 100% de la economía estadounidense que ya se enfrenta a severas repercusiones en todo el mundo contemporáneo. Estos puntos de vista son relevantes como testimonios de los autores que integramos la Unidad de Economía Mundial del Instituto de Investigaciones Económicas de la UNAM contando además con un equipo interdisciplinario de investigadores y académicos de México y del exterior

    Restoration of energy homeostasis by SIRT6 extends healthy lifespan

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    Aging leads to a gradual decline in physical activity and disrupted energy homeostasis. The NAD+-dependent SIRT6 deacylase regulates aging and metabolism through mechanisms that largely remain unknown. Here, we show that SIRT6 overexpression leads to a reduction in frailty and lifespan extension in both male and female B6 mice. A combination of physiological assays, in vivo multi-omics analyses and 13C lactate tracing identified an age-dependent decline in glucose homeostasis and hepatic glucose output in wild type mice. In contrast, aged SIRT6-transgenic mice preserve hepatic glucose output and glucose homeostasis through an improvement in the utilization of two major gluconeogenic precursors, lactate and glycerol. To mediate these changes, mechanistically, SIRT6 increases hepatic gluconeogenic gene expression, de novo NAD+ synthesis, and systemically enhances glycerol release from adipose tissue. These findings show that SIRT6 optimizes energy homeostasis in old age to delay frailty and preserve healthy aging

    The Impact of Culturing the Organ Preservation Fluid on Solid Organ Transplantation: A Prospective Multicenter Cohort Study

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    Background. We analyzed the prevalence, etiology, and risk factors of culture-positive preservation fluid and their impact on the management of solid organ transplant recipients. Methods. From July 2015 to March 2017, 622 episodes of adult solid organ transplants at 7 university hospitals in Spain were prospectively included in the study. Results. The prevalence of culture-positive preservation fluid was 62.5% (389/622). Nevertheless, in only 25.2% (98/389) of the cases were the isolates considered ?high risk? for pathogenicity. After applying a multivariate regression analysis, advanced donor age was the main associated factor for having culture-positive preservation fluid for high-risk microorganisms. Preemptive antibiotic therapy was given to 19.8% (77/389) of the cases. The incidence rate of preservation fluid?related infection was 1.3% (5 recipients); none of these patients had received preemptive therapy. Solid organ transplant (SOT) recipients with high-risk culture-positive preservation fluid receiving preemptive antibiotic therapy presented both a lower cumulative incidence of infection and a lower rate of acute rejection and graft loss compared with those who did not have high-risk culture-positive preservation fluid. After adjusting for age, sex, type of transplant, and prior graft rejection, preemptive antibiotic therapy remained a significant protective factor for 90-day infection. Conclusions. The routine culture of preservation fluid may be considered a tool that provides information about the contamination of the transplanted organ. Preemptive therapy for SOT recipients with high-risk culture-positive preservation fluid may be useful to avoid preservation fluid?related infections and improve the outcomes of infection, graft loss, and graft rejection in transplant patients

    Effectiveness of an mHealth intervention combining a smartphone app and smart band on body composition in an overweight and obese population: Randomized controlled trial (EVIDENT 3 study)

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    Background: Mobile health (mHealth) is currently among the supporting elements that may contribute to an improvement in health markers by helping people adopt healthier lifestyles. mHealth interventions have been widely reported to achieve greater weight loss than other approaches, but their effect on body composition remains unclear. Objective: This study aimed to assess the short-term (3 months) effectiveness of a mobile app and a smart band for losing weight and changing body composition in sedentary Spanish adults who are overweight or obese. Methods: A randomized controlled, multicenter clinical trial was conducted involving the participation of 440 subjects from primary care centers, with 231 subjects in the intervention group (IG; counselling with smartphone app and smart band) and 209 in the control group (CG; counselling only). Both groups were counselled about healthy diet and physical activity. For the 3-month intervention period, the IG was trained to use a smartphone app that involved self-monitoring and tailored feedback, as well as a smart band that recorded daily physical activity (Mi Band 2, Xiaomi). Body composition was measured using the InBody 230 bioimpedance device (InBody Co., Ltd), and physical activity was measured using the International Physical Activity Questionnaire. Results: The mHealth intervention produced a greater loss of body weight (–1.97 kg, 95% CI –2.39 to –1.54) relative to standard counselling at 3 months (–1.13 kg, 95% CI –1.56 to –0.69). Comparing groups, the IG achieved a weight loss of 0.84 kg more than the CG at 3 months. The IG showed a decrease in body fat mass (BFM; –1.84 kg, 95% CI –2.48 to –1.20), percentage of body fat (PBF; –1.22%, 95% CI –1.82% to 0.62%), and BMI (–0.77 kg/m2, 95% CI –0.96 to 0.57). No significant changes were observed in any of these parameters in men; among women, there was a significant decrease in BMI in the IG compared with the CG. When subjects were grouped according to baseline BMI, the overweight group experienced a change in BFM of –1.18 kg (95% CI –2.30 to –0.06) and BMI of –0.47 kg/m2 (95% CI –0.80 to –0.13), whereas the obese group only experienced a change in BMI of –0.53 kg/m2 (95% CI –0.86 to –0.19). When the data were analyzed according to physical activity, the moderate-vigorous physical activity group showed significant changes in BFM of –1.03 kg (95% CI –1.74 to –0.33), PBF of –0.76% (95% CI –1.32% to –0.20%), and BMI of –0.5 kg/m2 (95% CI –0.83 to –0.19). Conclusions: The results from this multicenter, randomized controlled clinical trial study show that compared with standard counselling alone, adding a self-reported app and a smart band obtained beneficial results in terms of weight loss and a reduction in BFM and PBF in female subjects with a BMI less than 30 kg/m2 and a moderate-vigorous physical activity level. Nevertheless, further studies are needed to ensure that this profile benefits more than others from this intervention and to investigate modifications of this intervention to achieve a global effect

    CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

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    Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research

    Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

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    The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

    Y-junction power splitter engineered through subwavelength metamaterials

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    2020 IEEE Photonics Conference (IPC), Vancouver, BC, Canada, 28 Sept.-1 Oct. 2020We present a Y-junction beam-splitter based on subwavelength metamaterials that mitigates losses associated with the fabrication limitations in the tip size of conventional Y-junctions. Simulations show minimal losses under 0.5 dB for TE 0 and TE 1 modes in a 300 nm range (1300 - 1600 nm).This work has been funded in part by the Spanish Ministry of Science, Innovation and Universities (MICINN) under grants RTI2018-097957-B-C33 and TEC2015- 71127-C2-1-R (FPI BES-2016-077798) and the Community of Madrid – FEDER funds (S2018/NMT-4326). This project has received funding from the Horizon 2020 research and innovation program under Marie Sklodowska-Curie grant No. 734331

    High-performance on-chip silicon beamsplitter based on subwavelength metamaterials for enhanced fabrication tolerance

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    11 pags., 7 figs., 2 tabs. -- This article belongs to the Special Issue Silicon Photonics: Synthesis and ApplicationsEfficient power splitting is a fundamental functionality in silicon photonic integrated circuits, but state-of-the-art power-division architectures are hampered by limited operational bandwidth, high sensitivity to fabrication errors or large footprints. In particular, traditional Y-junction power splitters suffer from fundamental mode losses due to limited fabrication resolution near the junction tip. In order to circumvent this limitation, we propose a new type of high-performance Y-junction power splitter that incorporates subwavelength metamaterials. Full three-dimensional simulations show a fundamental mode excess loss below 0.1 dB in an ultra-broad bandwidth of 300 nm (1400–1700 nm) when optimized for a fabrication resolution of 50 nm, and under 0.3 dB in a 350 nm extended bandwidth (1350–1700 nm) for a 100 nm resolution. Moreover, analysis of fabrication tolerances shows robust operation for the fundamental mode to etching errors up to ±20 nm. A proof-of-concept device provides an initial validation of its operation principle, showing experimental excess losses lower than 0.2 dB in a 195 nm bandwidth for the best-case resolution scenario (i.e., 50 nm).This work has been funded in part by the Spanish Ministry of Science and Innovation (MICINN) under grants RTI2018-097957-B-C33, RED2018-102768-T and TEC2015-71127-C2-1-R (FPI BES-2016-077798) and the Community of Madrid—FEDER funds (S2018/NMT-4326). This project has received funding from the Horizon 2020 research and innovation program under Marie SklodowskaCurie grant No. 734331.Peer reviewe

    Experimental characterization of an ultra-broadband dual-mode symmetric Y-junction based on metamaterial waveguides

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    7 pags., 9 figs., 1 tab.Silicon photonic integrated circuits routinely require 3-dB optical power dividers with minimal losses, small footprints, ultra-wide bandwidths, and relaxed manufacturing tolerances to distribute light across the chip and as a key building block to form more complex devices. Symmetric Y-junctions stand out among other power splitting devices owing to their wavelength-independent response and a straightforward design. Yet, the limited resolution of current fabrication methods results in a minimum feature size (MFS) at the tip between the two Y-junction arms that leads to significant losses for the fundamental mode. Here we propose to circumvent this limitation by leveraging subwavelength metamaterials in a new type of ultra-broadband and fabrication-tolerant Y-junction. An exhaustive experimental study over a 260 nm bandwidth (1420-1680 nm) shows excess loss below 0.3 dB for the fundamental transverse-electric mode (TE0) for a high-resolution lithographic process (MFS about 50 nm) and less than 0.5 dB for a fabrication resolution of 100 nm. Subwavelength Y-junctions with deterministically induced errors of plus-minus 10 nm further demonstrated robust fabrication tolerances. Moreover, the splitter exhibits excess loss lower than 1 dB for the first-order transverse-electric mode (TE1) within a 100 nm bandwidth (1475-1575 nm), using high-resolution lithography.This work has been funded by the Spanish Ministry of Science and Innovation (RTI2018-097957-B-C33, RED2018-102768-T, PID2020-115353RA-I00); the Spanish State Research Agency by ESF Investing in your future under grant PRE2021-096954 and European Union – NextGenerationEU, through the Recovery, Transformation and Resilience Plan (DIN2020-011488); the Community of Madrid – FEDER funds (S2018/NMT-4326); the European Union’s Horizon Europe research and innovation program under Marie Sklodowska-Curie grant No.101062518Peer reviewe
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