Role of LGP2 in the Innate Immune System upon Viral Infections

RIG-I-Iike receptors (RLRs) are a family of pattern recognition receptors that play an important role in the induction of cellular antiviral responses. RLRs comprise LGP2, RIG-I and MDA5. The latter two initiate antiviral signaling upon binding of viral cytoplasmic double-stranded (ds) RNA, resulting in the expression of interferons (IFNs) and IFN stimulated genes. LGP2 enhances MDA5- and represses RIG-I-mediated signaling even though in the latter case the physiological implication is less clear. Whether posttranslational modifications of LGP2 are involved in its diverse functions remains obscure. Hepatitis delta virus (HDV), a small RNA virus with a circular genome, is an important human pathogen responsible for the most severe form of viral hepatitis. HDV was shown to be sensed by MDA5 but the contribution of LGP2 to induction of the IFN response has not been explored. Hence, the aim of my thesis work was (i) to gain a deeper understanding of the role of LGP2 in regulating RLR signaling and (ii) to determine the contribution of LGP2 and its natural polymorphisms (encoding Q425R, N461S, R523Q) to sensing of HDV and other human viral pathogens. Using knockout and overexpression systems, immunocompetent lung A549 and hepatic HepaRGNTCP cells were measured for their IFN response upon viral infection and synthetic dsRNA stimulation. Mass spectrometry (MS) was performed to elucidate the impact of phosphorylation on the regulatory function of LGP2. Studies in A549 cells indicated faster RIG-I and delayed MDA5 signaling. LGP2 inhibited RIGI and strongly enhanced MDA5 signaling. RNA binding but not ATP hydrolysis was important for both LGP2 functions upon synthetic dsRNA stimulation. In HDV infected HepaRGNTCP cells LGP2 was shown to directly bind HDV RNA. Moreover, LGP2 RNA binding and ATP hydrolysis function were essential to fully activate an IFN response that impaired HDV replication. MS identified S169, S365 and S464 as differentially regulated LGP2 phosphorylation sites. Follow-up functional assays revealed enhanced RIG-I inhibition by the phosphoablative S169A substitution in LGP2. Preliminary data with an S365A/S464D LGP2 double mutation, mimicking steady-state phosphorylation at those sites, indicated delayed responsiveness of this LGP2 mutant towards HDV sensing. Investigation of the Q425R, N461S and R523Q LGP2 variants identified Q425R LGP2, which predominates in the African population, as a gain-of-function version. Q425R LGP2 enhanced basal and accelerated HDV-induced IFN signaling, thus lowering viral replication. This variant also enhanced MDA5-mediated antiviral signaling upon severe acute respiratory syndrome coronavirus type 2 infection. Mechanistically, Q425R LGP2 enhanced MDA5-RNA binding compared to wild-type LGP2. In conclusion, the results obtained during my thesis work broaden our understanding of the regulation of RLR signaling by LGP2. In the future, the gained knowledge might facilitate the development of new antiviral interventions by targeting RLRs for disease control

The potential for heat recovery from urban wastewater.

The pressing need of implementing climate change act and a commitment to increase renewable energy has led to the identification of number of secondary heat sources in UK (1). This paper focuses on heat recovery from urban sewage wastewater - a secondary heat source. The heat that is added by the consumer when it is heated, used and dumped in the sewer systems. The technique is not new and have been successfully implemented in many cities around the world with many others considering its deployment. In UK there is a growing interest to explore this new technology specially after the successful sewage heat recovery demonstration project at Borders College, Galashiels, Scotland - a joint venture between Scottish Water Horizons & SHARC Energy Systems (2). However, further experimental research is needed to build the evidence base, replicate and de-risk the concept elsewhere in the UK. The Home Energy 4 Tomorrow (HE4T) project at London South Bank University (LSBU) was created to address this evidence gap. The current paper is third in series of output on wastewater heat recovery in UK and is motivated by the need to introduce the research done to the industries where the data pertaining to sewage wastewater heat recovery is scarce and there is a lack of understanding of the flow behaviour of urban sewage. In this paper we present some measured data from a location in London, monthly variations in sewage wastewater temperature and the heat potential along with policy implications for UK heat strategy

Illegally Evading Attribution? Russia\u27s Use of Unmarked Troops in Crimea and International Humanitarian Law

The Crimean Crisis of February and March 2014 poses several questions to International Law. This Article explores one of them: Does the use of unmarked troops, soldiers in uniforms but without nationality insignia, in Crimea violate principles of International Humanitarian Law (IHL)? This Article first provides a brief summary of Crimea\u27s history and the facts of the 2014 Crimean Crisis. It will be argued that IHL is applicable to the events in Crimea in February and March 2014 since the unmarked soldiers are attributable to Russia--either as Russian nationals or through Russia\u27s exercise of control over them--and that there was no valid consent given justifying an intervention by invitation. The Article will argue that the principle of distinction under IHL is not violated since it requires only that combatants should be distinguishable from the civilian population but does not require a link between the combatant and a particular party to the conflict. Furthermore, it will be demonstrated that IHL regarding military uniforms leaves states a broad area of discretion as to the appearance of a military uniform and does not oblige combatants to visibly disclose their nationality by wearing emblems or insignia. This Article will also argue that the use of unmarked soldiers in the case at hand does not amount to illegal perfidy under IHL but--absent clear legal provisions and noticeable examples from state practice--must be regarded as a lawful ruse of war. Lastly, the final Part will consider whether it is wise to amend the current legal rules in order to prohibit the use of unmarked soldiers in similar situations arising in future armed conflicts and will spell out a recommendation

A new modal-based damage location indicator

Vibration-based damage detection techniques use the change in modal data as an indicator to assess damages in the structure. Knowing the structural dynamic characteristics of the healthy and damaged structure, the estimation of the damage location and severity is possible by solving an inverse problem. This paper presents a mathematical expression relating damage location and depth to the frequency shifts of the bending vibration modes. This expression permits the extraction of a series of coefficients that characterize each damage location and are independent of the damage severity. The vector aggregating these coefficients for a given location constitutes a Damage Location Indicator (DLI) that unambiguously characterizes the position of a geometrical discontinuity in the beam. A set of vectors typifying all locations along the beam may be used as patters opposable to the damage signature found by measurements. The similarity between the signature and one of the patterns indicates the location of damage

The use of virtual instruments in engineering education

AbstractVirtual instruments are used nowadays for measurement and control, but also as educational tools for students, being well accepted and stimulating innovation in the process of exploring the real world. It leads to discover interrelations, the phenomena are easier undersold and theory is better assimilated. The tool can be used in real laboratories as well as in virtual laboratories, constituting a support for self-learning or distance learning. This article presents how virtual instruments can be used in engineering education, with examples from our Vibration Laboratory, together with a qualitative research regarding the perception of students to this issue

Localization of transversal cracks in sandwich beams and evaluation of their severity

An algorithm to assess transversal cracks in composite structures based on natural frequency changes due to damage is proposed. The damage assessment is performed in two steps; first the crack location is found, and afterwards an evaluation of its severity is performed. The technique is based on a mathematical relation that provides the exact solution for the frequency changes of bending vibration modes, considering two terms. The first term is related to the strain energy stored in the beam, while the second term considers the increase of flexibility due to damage. Thus, it is possible to separate the problems of localization and severity assessment, which makes the localization process independent of the beams cross-section shape and boundary conditions. In fact, the process consists of comparing vectors representing the measured frequency shifts with patterns constructed using the mode shape curvatures of the undamaged beam. Once the damage is localized, the evaluation of its severity is made taking into account the global rigidity reduction. The damage identification algorithm was validated by experiments performed on numerous sandwich panel specimens

The influence of transversal crack geometry on the frequency changes of beams

Global non-destructive testing methods use changes in modal data as damage indicators. Depending on their geometry, damages influence the modal parameters in different way. While breathing cracks influence the natural frequencies due to only stiffness change, open cracks affect supplementary these frequencies due to loss of mass. This paper describes a study devoted to clarify the influence of the damage geometry on the natural frequencies of beams considering the two above mentioned aspects. First, analytical and numerical analyses are performed, in order to highlight the effect of mass changes on the frequency changes. Afterwards, the study focuses on breathing cracks in open and closing stages as well as on open cracks and emphasizes the influence of the geometrical discontinuity. It was demonstrated that, for beams with a breathing crack, a two degrees of freedom model is necessary to characterize its dynamic behavior. Finally, a relation between frequency changes and damage geometry and location is contrived

A versatile algorithm for estimating natural frequencies with high accuracy

Detection of damage requires an accurate estimation of the natural frequencies of the monitored structure. This paper introduces an algorithm implemented in Python which improves the frequency readability by increasing the number of spectral lines without requiring a signal extension in the time domain. We achieve this by overlapping several spectra calculated from the acquired signal repeatedly shortened. In this way, the overlapped spectrum gets an increased number of spectral lines. The dense mesh of spectral lines permits us to obtain a fine frequency resolution without being necessary an extension of the signal in the time domain. The high density of the spectral lines ensures a sufficient number of points on the main lobes that permits performing an efficient quadratic polynomial interpolation to find the maximizer. It represents the amplitude of the real frequency and is typically located on an inter-line position, thus cannot be found by standard frequency estimation. We implemented the algorithm in Python and tested it successfully for generated signals, containing one or more harmonics, with known frequencies

Turning national retrofit policies into local action: examples from the US BBNP and the Canadian eco-energy programs

Improving energy efficiency in existing dwellings is critical in efforts to address climate change. National level retrofit policies are useful for delivering large volumes of funding with a coordinated program brand. However, for countries such as the US and Canada, energy issues vary considerably nationwide and are therefore governed at the state or provincial level. Finding ways to calibrate national level policy objectives and structures for effective delivery at the local level is a critical policy priority, but is poorly understood by policymakers and underrepresented in academic research. This paper addresses this gap by analysing the US Better Buildings Neighborhood Program (2010-2013), and the Canadian Eco-Energy Retrofit Program (2009-2013). Both of these programs were created with a national level overarching structure and objectives, but were implemented in different ways at the state/provincial and local levels. The impact evaluations of each program found that they were broadly successful at the national level. This paper considers how each program targeted local action along three themes. 1) Housing stock factors including population, social, and demographic issues inherent to the spatial distribution and fundamentally unchangeable. 2) Program design factors consider issues such as leveraging local funding and resource pools. 3) Program delivery factors include implementation strategies for driving demand and workforce engagement. The results suggest that demographic factors are not predictive of overall program success (measured as total upgrades and/or energy savings). Effective program design and implementation can compensate for housing stock factors. A set of best practice principles are described for adapting national level program structures for effective local program delivery