11,781 research outputs found

    Analytical characterisation of the terahertz in-vivo nano-network in the presence of interference based on TS-OOK communication scheme

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    The envisioned dense nano-network inside the human body at terahertz (THz) frequency suffers a communication performance degradation among nano-devices. The reason for this performance limitation is not only the path loss and molecular absorption noise, but also the presence of multi-user interference and the interference caused by utilising any communication scheme, such as time spread ON—OFF keying (TS-OOK). In this paper, an interference model utilising TS-OOK as a communication scheme of the THz communication channel inside the human body has been developed and the probability distribution of signal-to-interference-plus-noise ratio (SINR) for THz communication within different human tissues, such as blood, skin, and fat, has been analyzed and presented. In addition, this paper evaluates the performance degradation by investigating the mean values of SINR under different node densities in the area and the probabilities of transmitting pulses. It results in the conclusion that the interference restrains the achievable communication distance to approximate 1 mm, and more specific range depends on the particular transmission circumstance. Results presented in this paper also show that by controlling the pulse transmission probability and node density, the system performance can be ameliorated. In particular, SINR of in vivo THz communication between the deterministic targeted transmitter and the receiver with random interfering nodes in the medium improves about 10 dB, when the node density decreases one order. The SINR increases approximate 5 and 2 dB, when the pulse transmitting probability drops from 0.5 to 0.1 and 0.9 to 0.5

    Microbial symbionts : a resource for the management of insect-related problems

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    Microorganisms establish with their animal hosts close interactions. They are involved in many aspects of the host life, physiology and evolution, including nutrition, reproduction, immune homeostasis, defence and speciation. Thus, the manipulation and the exploitation the microbiota could result in important practical applications for the development of strategies for the management of insect-related problems. This approach, defined as Microbial Resource Management (MRM), has been applied successfully in various environments and ecosystems, as wastewater treatments, prebiotics in humans, anaerobic digestion and so on. MRM foresees the proper management of the microbial resource present in a given ecosystem in order to solve practical problems through the use of microorganisms. In this review we present an interesting field for application for MRM concept, i.e. the microbial communities associated with arthropods and nematodes. Several examples related to this field of applications are presented. Insect microbiota can be manipulated: (i) to control insect pests for agriculture; (ii) to control pathogens transmitted by insects to humans, animals and plants; (iii) to protect beneficial insects from diseases and stresses. Besides, we prospect further studies aimed to verify, improve and apply MRM by using the insectsymbiont ecosystem as a model

    Microbial carcinogenic toxins and dietary anti-cancer protectants

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    Several toxins are known which account for the ability of some bacteria to initiate or promote carcinogenesis. These ideas are summarised and evidence is discussed for more specific mechanisms involving chymotrypsin and the bacterial chymotryptic enzyme subtilisin. Subtilisin and Bacillus subtilis are present in the gut and environment and both are used commercially in agriculture, livestock rearing and meat processing. The enzymes deplete cells of tumour suppressors such as deleted in colorectal cancer (DCC) and neogenin, so their potential presence in the food chain might represent an important link between diet and cancer. Over-eating increases secretion of chymotrypsin which is absorbed from the gut and could contribute to several forms of cancer linked to obesity. Inhibition of these serine proteases by Bowman–Birk inhibitors in fruit and vegetables could account for some of the protective effects of a plant-rich diet. These interactions represent previously unknown non-genetic mechanisms for the modification of tumour suppressor proteins and provide a plausible explanation contributing to both the pro-oncogenic effects of meat products and the protective activity of a plant-rich diet. The data suggest that changes to farming husbandry and food processing methods to remove these sources of extrinsic proteases might significantly reduce the incidence of several cancers

    Role of noncoding RNA in vascular remodelling

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    Purpose of review: Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are becoming fundamentally important in the pathophysiology relating to injury-induced vascular remodelling. We highlight recent studies that demonstrate the involvement of ncRNAs in vein graft disease, in in-stent restenosis and in pulmonary arterial hypertension, with a particular focus on endothelial cell and vascular smooth muscle cell function. We also briefly discuss the emerging role of exosomal-derived ncRNAs and how this mechanism impacts on vascular function. Recent findings: ncRNAs have been described as novel regulators in the pathophysiology of vascular injury, inflammation, and vessel wall remodelling. In particular, several studies have demonstrated that manipulation of miRNAs can reduce the burden of pathological vascular remodelling. Such studies have also shown that exosomal miRNA-mediated, cell-to-cell communication between endothelial cells and vascular smooth muscle cells is critical in the disease process. In addition to miRNAs, lncRNAs are emerging as regulators of vascular function in health and disease. Although lncRNAs are complex in both their sheer numbers and mechanisms of action, identifying their contribution to vascular disease is essential. Summary: Given the important roles of ncRNAs in vascular injury and remodelling together will their capacity for cell-to-cell communication, manipulating ncRNA might provide novel therapeutic interventions

    Plasmonic antennas and zero mode waveguides to enhance single molecule fluorescence detection and fluorescence correlation spectroscopy towards physiological concentrations

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    Single-molecule approaches to biology offer a powerful new vision to elucidate the mechanisms that underpin the functioning of living cells. However, conventional optical single molecule spectroscopy techniques such as F\"orster fluorescence resonance energy transfer (FRET) or fluorescence correlation spectroscopy (FCS) are limited by diffraction to the nanomolar concentration range, far below the physiological micromolar concentration range where most biological reaction occur. To breach the diffraction limit, zero mode waveguides and plasmonic antennas exploit the surface plasmon resonances to confine and enhance light down to the nanometre scale. The ability of plasmonics to achieve extreme light concentration unlocks an enormous potential to enhance fluorescence detection, FRET and FCS. Single molecule spectroscopy techniques greatly benefit from zero mode waveguides and plasmonic antennas to enter a new dimension of molecular concentration reaching physiological conditions. The application of nano-optics to biological problems with FRET and FCS is an emerging and exciting field, and is promising to reveal new insights on biological functions and dynamics.Comment: WIREs Nanomed Nanobiotechnol 201

    Discovery of new diketopiperazines inhibiting Burkholderia cenocepacia quorum sensing in vitro and in vivo

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    Burkholderia cenocepacia, an opportunistic respiratory pathogen particularly relevant for cystic fibrosis patients, is difficult to eradicate due to its high level of resistance to most clinically relevant antimicrobials. Consequently, the discovery of new antimicrobials as well as molecules capable of inhibiting its virulence is mandatory. In this regard quorum sensing (QS) represents a good target for anti-virulence therapies, as it has been linked to biofilm formation and is important for the production of several virulence factors, including proteases and siderophores. Here, we report the discovery of new diketopiperazine inhibitors of the B. cenocepacia acyl homoserine lactone synthase CepI, and report their anti-virulence properties. Out of ten different compounds assayed against recombinant CepI, four were effective inhibitors, with IC50 values in the micromolar range. The best compounds interfered with protease and siderophore production, as well as with biofilm formation, and showed good in vivo activity in a Caenorhabditis elegans infection model. These molecules were also tested in human cells and showed very low toxicity. Therefore, they could be considered for in vivo combined treatments with established or novel antimicrobials, to improve the current therapeutic strategies against B. cenocepacia
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