93 research outputs found

    System Identification for Limit Cycling Systems: A Case Study for Combustion Instabilities

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    This paper presents a case study in system identification for limit cycling systems. The focus of the paper is on (a) the use of model structure derived from physcal considerations and (b) the use of algorithms for the identification of component subsystems of this model structure. The physical process used in this case study is that of a reduced order model for combustion instabilities for lean premixed systems. The identification techniques applied in this paper are the use of linear system identification tools (prediction error methods), time delay estimation (based on Kalman filter harmonic estimation methods) and qualitative validation of model properties using harmonic balance and describing function methods. The novelty of the paper, apart from its practical application, is that closed loop limit cycle data is used together with a priori process structural knowledge to identify both linear dynamic forward and nonlinear feedback paths. Future work will address the refinement of the process presented in this paper, the use of alternative algorithms and also the use of control approachs for the validated model structure obtained from this paper

    Promoting positive change: Advancing the food well-being paradigm ☆

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    a b s t r a c t a r t i c l e i n f o Food well-being (FWB) is defined as "a positive psychological, physical, emotional, and social relationship with food at both the individual and societal levels" (Block et al., 2011, p. 6). This article seeks to advance our understanding of FWB along two dimensions. First, we discuss how awareness of consumer goals, as well as motivation and readiness to change, may help us to understand consumer preparedness to advance FWB. Second, we deconstruct the automatic and deliberative influences on food decision making into cognitive and emotional information that guide food choices and can be used by consumers to advance their own FWB. We close with a discussion of how measurement and strategies to influence FWB may allow researchers, policymakers, and industry to help consumers advance FWB

    2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.

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    Correction to: 2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales. Archives of Virology (2021) 166:3567–3579. https://doi.org/10.1007/s00705-021-05266-wIn March 2021, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by four families (Aliusviridae, Crepuscuviridae, Myriaviridae, and Natareviridae), three subfamilies (Alpharhabdovirinae, Betarhabdovirinae, and Gammarhabdovirinae), 42 genera, and 200 species. Thirty-nine species were renamed and/or moved and seven species were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.This work was supported in part through Laulima Government Solutions, LLC prime contract with the US National Institute of Allergy and Infectious Diseases (NIAID) under Contract No. HHSN272201800013C. J.H.K. performed this work as an employee of Tunnell Government Services (TGS), a subcontractor of Laulima Government Solutions, LLC under Contract No. HHSN272201800013C. This work was also supported in part with federal funds from the National Cancer Institute (NCI), National Institutes of Health (NIH), under Contract No. 75N91019D00024, Task Order No. 75N91019F00130 to I.C., who was supported by the Clinical Monitoring Research Program Directorate, Frederick National Lab for Cancer Research. This work was also funded in part by Contract No. HSHQDC-15-C-00064 awarded by DHS S&T for the management and operation of The National Biodefense Analysis and Countermeasures Center, a federally funded research and development center operated by the Battelle National Biodefense Institute (V.W.); and NIH contract HHSN272201000040I/HHSN27200004/D04 and grant R24AI120942 (N.V., R.B.T.). S.S. acknowledges partial support from the Special Research Initiative of Mississippi Agricultural and Forestry Experiment Station (MAFES), Mississippi State University, and the National Institute of Food and Agriculture, US Department of Agriculture, Hatch Project 1021494. Part of this work was supported by the Francis Crick Institute which receives its core funding from Cancer Research UK (FC001030), the UK Medical Research Council (FC001030), and the Wellcome Trust (FC001030).S

    2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.

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    In March 2021, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by four families (Aliusviridae, Crepuscuviridae, Myriaviridae, and Natareviridae), three subfamilies (Alpharhabdovirinae, Betarhabdovirinae, and Gammarhabdovirinae), 42 genera, and 200 species. Thirty-nine species were renamed and/or moved and seven species were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV

    DEFINING THE GUN1-FTSH INTERACTIONS IN CHLOROPLAST BIOGENESIS IN ARABIDOPSIS THALIANA

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    The GENOMES UNCOUPLED 1 (GUN1) gene has been reported to encode a chloroplast-localized pentatricopeptide-repeat protein (PPR), which acts to integrate multiple indicators of plastid developmental stage and altered plastid function, as part of chloroplast-to-nucleus retrograde communication. However, the molecular mechanisms underlying the GUN1-dependent signal integration have remained elusive, until the recent identification of a set of GUN1- interacting proteins, by co-immunoprecipitation and mass-spectrometric analyses, as well as protein\u2013protein interaction assays. Within the list of GUN1 interactors the FtsH1, FtsH2, FtsH5 and FtsH8 subunits, that make up the thylakoid FTSH protease complex, were identified. The FtsH subunits are part of the ATP-dependent metalloprotease family and they play a fundamental role in the maintenance of the chloroplast protein homeostasis. In this thesis, I show that FtsH2 and FtsH5 subunits have a really important genetic interaction with GUN1 during the chloroplast biogenesis process in Arabidopsis cotyledons. In particular, I observed that GUN1 is important for the accumulation of the FtsH subunits in the thylakoid membranes, and for the import of several plastid precursor proteins that, in the absence of GUN1 protein, accumulate in the cytosol, with the consequent increase in total protein ubiquitination and cytosolic chaperone abundance. In the attempt to give a molecular explanation to the observation reported above, I was able to demonstrate that in condition of plastid protein homeostasis alteration, GUN1 controls the accumulation of Nuclear encoded RNA polymerase (NEP)-dependent transcripts and, indirectly, affects the chloroplast protein import apparatus, since a major component of the 1MDa TIC complex (Translocon at the Inner membrane of the Chloroplasts), i.e. Tic214, is encoded by the plastid genome. Such a defect in Tic214 accumulation appears to destabilize the entire plastid import machinery both in terms of protein amount and post-translation modification, as shown by the high ubiquitination levels of Toc34 subunit. Strikingly, such chloroplast alterations are sensed by nuclear transcription factors, as shown by the negative effect on the accumulation of HY5, a main transcription factor involved in retrograde signaling and chloroplast biogenesis. Overall, during this three year as Ph.D. student I believed to have discovered the primary function of GUN1 protein, shining a new light on the intricate network of chloroplast-nucleus communication

    Involvement of autophagy in ovarian cancer: a working hypothesis

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    Abstract Autophagy is a lysosomal-driven catabolic process that contributes to preserve cell and tissue homeostases through the regular elimination of damaged, aged and redundant self-constituents. In normal cells, autophagy protects from DNA mutation and carcinogenesis by preventive elimination of pro-oxidative mitochondria and protein aggregates. Mutations in oncogenes and oncosuppressor genes dysregulate autophagy. Up-regulated autophagy may confer chemo- and radio-resistance to cancer cells, and also a pro-survival advantage in cancer cells experiencing oxygen and nutrient shortage. This fact is the rationale for using autophagy inhibitors along with anti-neoplastic therapies. Yet, aberrant hyper-induction of autophagy can lead to cell death, and this phenomenon could also be exploited for cancer therapy. The actual level of autophagy in the cancer cell is greatly affected by vascularization, inflammation, and stromal cell infiltration. In addition, small non-coding microRNAs have recently emerged as important epigenetic modulators of autophagy. The present review focuses on the potential involvement of macroautophagy, and on its genetic and epigenetic regulation, in ovarian cancer pathogenesis and progression.</p

    GUN1, a Jack-Of-All-Trades in Chloroplast Protein Homeostasis and Signaling

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    The GENOMES UNCOUPLED 1 (GUN1) gene has been reported to encode a chloroplast-localized pentatricopeptide-repeat protein, which acts to integrate multiple indicators of plastid developmental stage and altered plastid function, as part of chloroplast-to-nucleus retrograde communication. However, the molecular mechanisms underlying signal integration by GUN1 have remained elusive, up until the recent identification of a set of GUN1-interacting proteins, by co-immunoprecipitation and mass-spectrometric analyses, as well as protein-protein interaction assays. Here, we review the molecular functions of the different GUN1 partners and propose a major role for GUN1 as coordinator of chloroplast translation, protein import, and protein degradation. This regulatory role is implemented through proteins that, in most cases, are part of multimeric protein complexes and whose precise functions vary depending on their association states. Within this framework, GUN1 may act as a platform to promote specific functions by bringing the interacting enzymes into close proximity with their substrates, or may inhibit processes by sequestering particular pools of specific interactors. Furthermore, the interactions of GUN1 with enzymes of the tetrapyrrole biosynthesis (TPB) pathway support the involvement of tetrapyrroles as signaling molecules in retrograde communication
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