2,505 research outputs found

    Noise induced hearing loss: the role of oxidative stress

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    Introduction: Noise-induced hearing loss (NIHL) is a relevant source of hearing disability affecting the general population, and accounts for about 16% of all the reported cases of disabling hearing loss in the adult population worldwide. NIHL can follow workplace-related and recreational noise exposure, and can be influenced by individual factors such as age, sex, genetic predisposition and socio-economic factors. Objectives: The aim of this paper is to provide a quick overview of the principal ndings in noise induced hearing loss, focusing on the role of oxidative stress and antioxidant intervention. Review: Oxidative stress plays a central role in leading to a condition of NIHL. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) largely participate in cellular mechanisms that underlie mainly the outer hair cell death after noise exposure and lead to sensorineural hearing loss. The beneficial effects of antioxidant supplementation have been demonstrated by several experimental studies in animals, while the observed results in humans are mixed. Conclusion: NIHL still represents a widespread condition among the general population; with a higher prevalence in developing countries among workers, and in developed countries among young adults exposed to leisure noise. Extensive literature confirms that increasing antioxidant levels in the organ of Corti may be an appropriate approach towards understanding NIHL in humans by increasing the endogenous antioxidant response or by administering antioxidant molecules systemically or locally

    Potential of PM-selected components to induce oxidative stress and root system alteration in a plant model organism

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    Over the last years, various acellular assays have been used for the evaluation of the oxidative potential (OP) of particular matter (PM) to predict PM capacity to generate reactive oxygen (ROS) and nitrogen (RNS) species in biological systems. However, relationships among OP and PM toxicological effects on living organisms are still largely unknown. This study aims to assess the effects of atmospheric PM-selected components (brake dust - BD, pellet ash - PA, road dust - RD, certified urban dust NIST1648a - NIST, soil dust - S, coke dust - C and Saharan dust - SD) on the model plant A. thaliana development, with emphasis on their capacity to induce oxidative stress and root morphology alteration. Before growing A. thaliana in the presence of the PM-selected components, each atmospheric dust has been chemically characterized and tested for the OP through dithiothreitol (DTT), ascorbic acid (AA) and 2′,7′-dichlorofluorescin (DCFH) assays. After the exposure, element bioaccumulation in the A. thaliana seedlings, i.e., in roots and shoots, was determined and both morphological and oxidative stress analyses were performed in roots. The results indicated that, except for SD and S, all the tested dusts affected A. thaliana root system morphology, with the strongest effects in the presence of the highest OPs dusts (BD, PA and NIST). Principal component analysis (PCA) revealed correlations among OPs of the dusts, element bioaccumulation and root morphology alteration, identifying the most responsible dust-associated elements affecting the plant. Lastly, histochemical analyses of NO and O2•− content and distribution confirmed that BD, PA and NIST induce oxidative stress in A. thaliana, reflecting the high OPs of these dusts and ultimately leading to cell membrane lipid peroxidation

    Recupero dell'offset di frequenza su canali con fading selettivo nel tempo

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    In questo lavoro di tesi si è sviluppato un pacchetto software per la simulazione del livello fisico di un sistema single carrier su canale selettivo nel tempo ed in particolare è stato implementato un nuovo algoritmo per il recupero del sincronismo di frequenza. Il simulatore permette di valutare le prestazioni del sistema in termini di Mean Square Estimation Error (MSEE) e di Bias del sincronizzatore di frequenza. Nel capitolo 1 sono descritti la struttura generale del sistema ed in particolare i vari blocchi che lo compongono, la struttura del burst ed il modello del canale multipath considerato. Nel capitolo 2 si analizza l’algoritmo fornendo anche una sintetica descrizione di un altro approccio a cui verrà in seguito fatto riferimento come pietra di paragone per valutare la bontà dei risultati conseguiti. Nel capitolo 3 si illustra il funzionamento del simulatore soffermandosi in dettaglio sulle varie subroutines utilizzate, infine vengono esposti i risultati grafici relativi alle simulazioni con canale rispettivamente awgn e tempo-selettivo

    Cooperative control of 3D mobile agents with limited sensing capabilities

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    Lo studio dei sistemi cooperanti richiede l'uso di tecniche derivate da diverse branche dell'ingegneria, delle scienze informatiche e della matematica. Questo lavoro propone una formulazione matematica da usare per la definizione e l'analisi di una particolare classe di gruppi di veicoli. Si prendono in considerazione flotte di agenti nello spazio 3d; vengono analizzate le possiblità di cooperazione quando la comunicazione è limitata all'acquisizione attraverso sensori, con campo visivo limitato, della posizione di altri veicoli. Allo scopo di studiare gli effetti dei limiti di comunicazione viene formulato il problema del rendezvous, per il quale è fornita una soluzione. I risultati ottenuti sono in linea con quelli tradizionalmente ottenuti nell'ambito del controllo cooperativo. The field of cooperative control for groups of vehicles lies within several different engineering, computer sciences and mathematical branches. This work proposes a mathematical framework to be used in defining and analysing a particular class of vehicles' groups. Fleets of agents moving in the 3d space are considered; their ability to cooperate when no communication but position sensing-using a limited field of view-is possible, is analysed. The statement of a slightly modified version of the rendezvous problem for the considered system and an algorithm to solve it are used as a mean to explore the effects of the communication limits. The obtained results are on the same level with traditional results of cooperative control

    A Humanistic, Culturally Sensitive Approach to Telesupervision: A Case Study

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    In this case study, the unique features of providing telesupervision in a humanistic, systematic approach that takes in cultural issues are discussed.With the COVID-19 pandemic, therapists who supervise students have not only moved to various online platforms to supervise students, but also had to adjust to the uniqueness of telesupervision and to issues brought into supervision such as culture. In this case study a strong working alliance start to develop with this student prior to starting telesupervision. It allowed trust to develop by getting to know the student, looking at what the student wanted in during supervision and the requirements of the student’s school. All of this was done to by using a client-centered/collaborative approach while finalizing a supervision contract. As this trust started to build and supervision moved to telesupervision, the writer helped the student explore self with genograms and cultural issues. As this was occurring, as the supervisor, it was important to keep account of myself and how that affected the supervisor relationship

    Influence of input climatic data on simulations of annual energy needs of a building: energyplus and WRF modeling for a case study in Rome (Italy)

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    The simulation of the energy consumptions in an hourly regime is necessary in order to perform calculations on residential buildings of particular relevance for volume or for architectural features. In such cases, the simplified methodology provided by the regulations may be inadequate, and the use of software like EnergyPlus is needed. To obtain reliable results, usually, significant time is spent on the meticulous insertion of the geometrical inputs of the building, together with the properties of the envelope materials and systems. Less attention is paid to the climate database. The databases available on the EnergyPlus website refer to airports located in rural areas near major cities. If the building to be simulated is located in a metropolitan area, it may be affected by the local heat island, and the database used as input to the software should take this phenomenon into account. To this end, it is useful to use a meteorological model such as the Weather Research and Forecasting (WRF) model to construct an appropriate input climate file. A case study based on a building located in the city center of Rome (Italy) shows that, if the climatic forcing linked to the heat island is not considered, the estimated consumption due to the cooling is underestimated by 35–50%. In particular, the analysis and the seasonal comparison between the energy needs of the building simulated by EnergyPlus, with the climatic inputs related to two airports in the rural area of Rome and with the inputs provided by the WRF model related to the center of Rome, show discrepancies of about (i) WRF vs. Fiumicino (FCO): Δ = −3.48% for heating, Δ = 49.25% for cooling; (ii) WRF vs. Ciampino (CIA): Δ = −7.38% for heating, Δ = +35.52% for cooling

    Infectious agents in atherosclerotic cardiovascular diseases through oxidative stress

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    Accumulating evidence demonstrates that vascular oxidative stress is a critical feature of atherosclerotic process, potentially triggered by several infectious agents that are considered as risk co-factors for the atherosclerotic cardiovascular diseases (CVDs). C. pneumoniae has been shown to upregulate multiple enzymatic systems capable of producing reactive oxygen species (ROS) such as NADPH oxidase (NOX) and cyclooxygenase in vascular endothelial cells, NOX and cytochrome c oxidase in macrophages as well as nitric oxide synthase and lipoxygenase in platelets contributing to both early and late stages of atherosclerosis. P. gingivalis seems to be markedly involved in the atherosclerotic process as compared to A. actinomycetemcomitans contributing to LDL oxidation and foam cell formation. Particularly interesting is the evidence describing the NLRP3 inflammasome activation as a new molecular mechanism underlying P. gingivalis-induced oxidative stress and inflammation. Amongst viral agents, immunodeficiency virus-1 and hepatitis C virus seem to have a major role in promoting ROS production, contributing, hence, to the early stages of atherosclerosis including endothelial dysfunction and LDL oxidation. In conclusion, oxidative mechanisms activated by several infectious agents during the atherosclerotic process underlying CVDs are very complex and not well-known, remaining, thus, an attractive target for future research

    Cadmium and arsenic-induced-stress differentially modulates Arabidopsis root architecture, peroxisome distribution, enzymatic activities and their nitric oxide content

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    In plant cells, cadmium (Cd) and arsenic (As) exert toxicity mainly by inducing oxidative stress through an imbalance between the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), and their detoxification. Nitric oxide (NO) is a RNS acting as signalling molecule coordinating plant development and stress responses, but also as oxidative stress inducer, depending on its cellular concentration. Peroxisomes are versatile organelles involved in plant metabolism and signalling, with a role in cellular redox balance thanks to their antioxidant enzymes, and their RNS (mainly NO) and ROS. This study analysed Cd or As effects on peroxisomes, and NO production and distribution in the root system, including primary root (PR) and lateral roots (LRs). Arabidopsis thaliana wild-type and transgenic plants enabling peroxisomes to be visualized in vivo, through the expression of the 35S-cyan fluorescent protein fused to the peroxisomal targeting signal1 (PTS1) were used. Peroxisomal enzymatic activities including the antioxidant catalase, the H2O2-generating glycolate oxidase, and the hydroxypyruvate reductase, and root system morphology were also evaluated under Cd/As exposure. Results showed that Cd and As differently modulate these activities, however, catalase activity was inhibited by both. Moreover, Arabidopsis root system was altered, with the pollutants differently affecting PR growth, but similarly enhancing LR formation. Only in the PR apex, and not in LR one, Cd more than As caused significant changes in peroxisome distribution, size, and in peroxisomal NO content. By contrast, neither pollutant caused significant changes in peroxisomes size and peroxisomal NO content in the LR apex

    ATP-binding cassette transporters in progression and clinical outcome of pancreatic cancer: What is the way forward?

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    © The Author(s) 2018. Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive diseases and is characterized by high chemoresistance, leading to the lack of effective therapeutic approaches and grim prognosis. Despite increasing understanding of the mechanisms of chemoresistance in cancer and the role of ATPbinding cassette (ABC) transporters in this resistance, the therapeutic potential of their pharmacological inhibition has not been successfully exploited yet. In spite of the discovery of potent pharmacological modulators of ABC transporters, the results obtained in clinical trials have been so far disappointing, with high toxicity levels impairing their successful administration to the patients. Critically, although ABC transporters have been mostly studied for their involvement in development of multidrug resistance (MDR), in recent years the contribution of ABC transporters to cancer initiation and progression has emerged as an important area of research, the understanding of which could significantly influence the development of more specific and efficient therapies. In this review, we explore the role of ABC transporters in the development and progression of malignancies, with focus on PDAC. Their established involvement in development of MDR will be also presented. Moreover, an emerging role for ABC transporters as prognostic tools for patients' survival will be discussed, demonstrating the therapeutic potential of ABC transporters in cancer therapy
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