3,283 research outputs found

    30-nm wavelength conversion at 10 Gbit/s by four-wave mixing in a semiconductor optical amplifier

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    Four-wave mixing (FWM) in semiconductor optical amplifiers (SOAs) is currently the only available strictly transparent wavelength-conversion technique, which is not penalized by phase matching. The span of the conversion is limited primarily by conversion efficiency and signal-to-noise (SNR) issues, both of which are expected to improve with the use of longer SOAs. In this paper, we demonstrate significantly enhanced performance of long converters in a system experiment at 10 Gbit/s. The experiment shows for the first time, to our knowledge, that FWM wavelength down-conversions can span the full gain bandwidth of erbium-doped fiber amplifiers

    Wavelength conversion at 10 Gb/s by four-wave mixing over a 30-nm interval

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    We show that the use of a long semiconductor optical amplifier increases the error-free conversion interval of a four-wave mixing (FWM)-based wavelength converter. 30-nm wavelength down-conversion and 15-nm up-conversion have been obtained at 10 Gb/s. This result is a significant improvement over the previous best performance of a FWM-based wavelength converter and suggests that the full erbium-doped fiber amplifier bandwidth can be covered with FWM wavelength converters

    Editorial: The Benefits of Nature-Based Solutions to Psychological Health

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    Nature-based solutions (NBS) have been defined by the European Commission as actions aiming to provide environmental, social, and economic benefits through the inclusion of natural features in the urban environment. The exposure to natural environments, including NBS in urban contexts, has been associated with a large number of health benefits (Ulrich et al., 1991; Berman et al., 2008; Spano et al., 2020), particularly mental health and well-being among those most studied. Earlier studies on such benefits have been mainly experimental, investigating the short-term effects of brief exposure to natural environments on stress reduction and cognitive restoration (Kaplan and Kaplan, 1989; Berto, 2005; Nilsson et al., 2010; Carrus et al., 2017). More recently, large-scale epidemiological studies have provided further evidence of the long-term effects of sustained exposure to green spaces on mental health and well-being throughout the life course (Hartig et al., 2014; Gascon et al., 2015; McCormick, 2017; de Keijzer et al., 2020). Several dimensions characterize the human–nature interaction. In this sense, the present Research Topic was intended to provide an overview of studies focusing on the association of exposure to natural environments in urban, peri-urban, and rural settings with psychological well-being and mental health from different perspectives

    From Microbial Ecology to Innovative Applications in Food Quality Improvements: the Case of Sourdough as a Model Matrix.

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    Since millennia, humankind has exploited microbial diversity associated to give foodmatrices in order to obtain fermented foods and beverages, resulting in products with improvedquality and extended shelf life. This topic has received deserved and continuous interest in thescientific community, for the reason of its significance as a driver of innovation in the food and beveragesector. In this review paper, using sourdough as a model matrix, we provide some insights into thefield, testifying the relevance as a transdisciplinary subject. Firstly, we encompassed the prokaryoticand eukaryotic microbial diversity associated with the sourdough ecosystems. The importance ofthis micro-biodiversity in the light of flour-related chemical diversity was examined. Finally, wehighlighted the increasing interest in microbial-based applications oriented toward biocontrol solutionin the field of sourdough-based products (i.e., bread)

    Interleukin-1beta and glutamate activate the NF-kappaB/Rel binding site from the regulatory region of the Amyloid Precursor Protein gene in primary neuronal cultures

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    We originally reported that members of the family of transcription factors NF-kappaB/Rel can specifically recognize two identical sequences, referred to as APPkappaB sites, which are present in the 5'-regulatory region of the APP gene. Here we show that the APPkappaB sites interact specifically with a complex which contains one of the subunits of the family, defined as p50 protein, and that they act as positive modulators of gene transcription in cells of neural origin. Additionally, the nuclear complex specifically binding to the APPkappaB sites is constitutively expressed in primary neurons from rat cerebellum and it is up-regulated in response to both the inflammatory cytokine interleukin-1beta (IL-1beta) and the excitatory amino acid glutamate. Since IL-1, whose levels are known to be induced in brain of individuals affected by Alzheimer's disease, and glutamate, are stimuli which have been regarded as major actors on the stage of neurodegenerative processes, we believe our evidence as potentially relevant for understanding the neuropathology associated with Alzheimer's disease

    Post-ischemic brain damage: NF-kappaB dimer heterogeneity as a molecular determinant of neuron vulnerability

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    Nuclear factor-kappaB (NFkB) has been proposed to serve a dual function as a regulator of neuron survival in pathological conditions associated with neurodegeneration. NF-jB is a transcription family of factors comprising five different proteins, namely p50, RelA ⁄ p65, c-Rel, RelB and p52, which can combine differently to form active dimers in response to external stimuli. Recent research shows that diverse NF-jB dimers lead to cell death or cell survival in neurons exposed to ischemic injury. While the p50 ⁄ p65 dimer participates in the pathogenesis of post-ischemic injury by inducing pro-apoptotic gene expression, c-Rel-containing dimers increase neuron resistance to ischemia by inducing anti-apoptotic gene transcription. We present, in this report, the latest findings and consider the therapeutic potential of targeting different NF-kB dimers to limit ischemia-associated neurodegeneration

    Nouveauté et analyse critique des facteurs de pronostic et de réponses thérapeutiques

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