cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Role of the FOXO-FOXM1 axis in the progression of metastatic breast cancer
Creators: name: Bella, Laura
Publisher: name: Imperial College London
Year: 2016

description: Lack of available therapies to combat and prevent tumour progression have rendered tumour metastasis one of the primary causes of mortality in cancer. Interestingly, the insurgence of tumour resistance to cytotoxic chemotherapy has been linked to tumour relapse and death. This project aimed to characterise the phenotypical and behavioural alteration that breast cancer cell lines adopt when developing resistance to the anthracycline (epirubicin) and the taxane (paclitaxel). It then aimed to associate these alterations with varying levels of the Forkhead Box proteins FOXO-FOXM1 expression, to determine whether these transcription factors, extensively characterised for their role in both the development of drug resistance and individual aspects of cancer progression, could cause the changes noted in these cell lines. Using a combination of in vitro techniques and the novel in vivo zebrafish embryo model, developed during this project, the drug resistant MCF-7 breast cancer cell lines were shown to have undergone the epithelial to mesenchymal transition and possess significantly increased capacities to migrate and form mammospheres in vitro as well as induce neoangiogenesis and metastasize in vivo, when compared with their parental MCF-7 WT cells. More in depth analysis demonstrated FOXO3 endogenous suppression was key to the loss of E-cadherin expression, whilst the overexpression of FOXM1 could be directly linked to the increased cancer progression capacities noted in the resistant cell lines. Then, KIF20A was identified as a critical FOXM1 down-stream effector that could regulate all aspects of cancer progression through a hypothesized structural interaction with the cytoskeleton. Alternatively, SOX4 was shown to possess a completely novel angiogenic function, which could, when inhibited, completely prevent breast cancer induced angiogenesis in vivo. In conclusion, this project unveiled a novel rate-limiting role for FOXO-FOXM1, as well as KIF20A and SOX4 as prognostic markers and potential drug targets to combat the cancer progression of breast cancer.
Cardiovascular and sexual health effects of postmenopausal testosterone therapy
Creators: name: Maclaran, Kate Alix
Publisher: name: Imperial College London
Year: 2015

description: Introduction: Testosterone is frequently used as part of postmenopausal hormone therapy (HT) but few preparations have been approved for use in women. The effects of androgens on the female cardiovascular (CV) system remain poorly understood and concerns exist over the long-term CV safety of testosterone therapy. This study aimed to investigate the CV effects of the transdermal testosterone patch (TTP) in postmenopausal women, on concomitant HT, using surrogate markers for CV disease. Methods: This open label pilot study investigated the effects of 12 weeks TTP on arterial stiffness and endothelial function in 21 postmenopausal women. Primary outcome measures were augmentation index (AIx), assessed by pulse wave analysis (PWA), reactive hyperaemic index (RHI) using peripheral arterial tonometry (PAT) and insulin resistance using the homeostasis model (HOMA-IR). Libido (brief profile of female sexual function (B-PFSF)), anthropometry, lipids and serum hormone levels were also assessed. Results: Testosterone was associated with significantly improved libido (increased B-PFSF score 5.05 points (p<0.0001)), increased total testosterone (1.3 nmol/L, p<0.0001) and free androgen index (2.0, p<0.001). Hip circumference significantly reduced (-0.74 cm, p<0.05) but there was no change in weight, body mass index, waist circumference or blood pressure. Total cholesterol was unchanged, but there were small but significant decreases in high-density lipoprotein (HDL) cholesterol (-0.25 mmol/L, p<0.05) and lipoprotein (a) levels (-3.11mg/L , p<0.05). Fasting insulin, fasting glucose and insulin resistance were unchanged. There was no change to AIx (1.07, 95% CI -3.85-1.72, p=0.43), or RHI (0.06, 95% CI 0.19-0.31, p=0.61) but there was a significant increase in salbutamol-mediated vasodilatation (p<0.05), assessed by PWA. Conclusion: These data suggest that short-term physiological testosterone does not adversely affect arterial stiffness and may improve markers of endothelial function. Testosterone use was associated with reductions in HDL cholesterol and lipoprotein (a), but whether this has significant long-term CV effects remains unclear.
The role of cohesin in long-range gene regulation
Creators: name: Ing-Simmons, Elizabeth
Publisher: name: Imperial College London
Year: 2016

description: The cohesin complex holds together sister chromatids after DNA replication: this is vital for correct segregation of chromosomes into daughter cells at mitosis. As well as this cell cycle role, cohesin has been implicated in regulating gene expression during interphase, through cohesin-mediated interactions between genes and regulatory elements. Such regulatory interactions tend to take place within topological domains. Topological domains are genomic regions which have preferential self-interactions in the 3D organisation of chromatin within the nucleus. Domain boundaries are enriched for cohesin and its frequent binding partner CTCF, and depletion of cohesin has been shown to affect genome organisation into topological domains, as well as causing the loss of enhancer–promoter interactions at some loci. However, it is unclear how cohesin-mediated interactions influence gene expression genome-wide. In this thesis, I use comparisons of control and cohesin-deficient mouse thymocytes to show that cohesin-mediated interactions between enhancers are important for the regulation of gene expression. Cohesin and CTCF are enriched at enhancers, and particularly at clusters of enhancer elements known as "super-enhancers". Cohesin mediates interactions between these enhancer elements, leading to their spatial clustering. While H3K27ac, H3K4me1, and transcription at enhancers are not affected by cohesin depletion, interactions between enhancer elements are lost. Enhancer-proximal genes are preferentially deregulated in cohesin-deficient cells, suggesting that these interactions are important for gene regulation. Deregulation of gene expression tends to occur in a coordinated manner within topological domains, which emphasises the importance of the structural organisation of the genome for gene regulation. Therefore, in this thesis I also consider models for the processes shaping genome organisation. I present evidence supporting key roles for cohesin and CTCF in these processes. Taken together, these results show that cohesin is important for both the organisation of topological domains and regulatory interactions within them.
CCWI2017: F41 'Why are Line Search Methods Needed for Hydraulic DDM and PDM Solvers?'
Creators: name: Piller, Olivier
name: Sylvan Elhay
name: Deuerlein, Jochen
name: Simpson, Angus
Publisher: name: The University of Sheffield
Year: 2017
Subjects: subject: 90599 Civil Engineering not elsewhere classified
subject: FOS: Civil engineering

description: It is common that non-convergence problems occur for simulations under normal or abnormal operations. Among the main causes, there are the use of sublinear functions for calculation of the hydraulic steady-state, some derivative issues and an ill-conditioned iteration matrix in the solution method. The objective of this paper is to specify non-convergence cases for existing hydraulic software solutions. The damped Newton solution together with regularization techniques are proposed for ensuring global convergence, whatever the initial solution. Failures of convergence are shown to exist even on small case studies.
Influence of the intestinal microbiota on the immune response to oral poliovirus and rotavirus vaccines in a low-income community in south India
Creators: name: Parker, Edward
Publisher: name: Imperial College London
Year: 2016

description: Oral vaccines have consistently underperformed in the low-income countries where they are needed most. This has formed a potent obstacle to several public health initiatives that rely on such vaccines, including the polio eradication endgame. This thesis examines the hypothesis that the composition of the intestinal microbiota – including both pathogenic and commensal microbes – contributes to the impaired performance of oral vaccines in low-income countries. Based on a systematic review and meta-analysis, we observed a decrease in the likelihood of responding to oral poliovirus vaccine (OPV) among infants with concurrent enterovirus infections or diarrhoea. We subsequently tested for multiple bacterial, viral, and eukaryotic enteropathogens and sequenced the 16S rRNA gene (to characterise the total bacterial microbiota) among infants living in a semi-urban slum in south India who had received Rotarix (an oral rotavirus vaccine) and OPV at 6 and 10 weeks of age. We did not observe significant differences in bacterial microbiota composition according to seroconversion status for either vaccine. However, the presence of bacterial pathogens was positively correlated with Rotarix response and negatively correlated with OPV response, suggesting that distinct mechanisms may impact these vaccines. The same methods were applied to samples from 6–11 month-old infants who had received OPV after a 3-day course of azithromycin or placebo. Once again, the association between bacterial microbiota composition and vaccine outcome was modest, although microbiota diversity was negatively correlated with vaccine poliovirus replication. As expected, viral pathogens were associated with a decrease in OPV immunogenicity. Moreover, recently acquired viral infections appeared to inhibit OPV response to a greater extent than persistent viruses. Together, these findings have substantiated the inhibitory effect of viral pathogens on OPV response, while implicating bacterial pathogens as a potential risk factor for OPV failure in early infancy. Risk factors for rotavirus vaccine failure remain elusive.
CONTENT OF TYPES OF FICTION AND THE CONNECTION BETWEEN THEM
Creators: name: Qurbonov, Asqar
Publisher: name: Zenodo
Year: 2024

description: The article presents reflections on the influence of fiction on the formation of personality spirituality and its perception, knowledge and beliefs about the universe, the qualities and qualities of peat on which juz'an finds a decision influenced by fiction. A structural analysis of fiction, functions, and the process of changing under the influence of contemporary trends have also been outlined.
Illuminating cAMP dynamics at the synapse with multiphoton FLIM-FRET Imaging
Creators: name: West, Lucien
Publisher: name: Imperial College London
Year: 2016

description: The study of signalling pathways within mammalian physiology has long been hindered by the size of the players involved, being far beyond the realms of the conventional light microscope. The advent of advanced fluorescent imaging techniques has revolutionised our capabilities to probe biological processes. The work in this thesis particularly utilised Förster resonance energy transfer (FRET), a fluorescence-based technique that can provide functional readouts of the processes underlying cellular function. Specifically I worked to develop and optimise a fluorescence imaging system for investigating the dynamics and function of cyclic adenosine monophosphate (cAMP), a ubiquitous second messenger. The neuroscientific study of how the brain can learn and recall memories is a rapidly advancing field. The current challenges of tackling dementias, such as Alzheimer’s disease, and preventing memory loss can only be addressed through better understanding of how memories can be stored. It is now believed that neurons retain memories within their synapses, the femtolitre structures that determine the strength of these connections. cAMP has been shown to play a distinctive role in orchestrating the retention of long term memory at the synaptic level. However, its spatial and temporal activation profiles are still not fully understood. To address this, my PhD project combined FRET readouts with cutting edge imaging techniques applied to synapses in neuronal cultures that provide reasonably convenient optical access. By examining the structure of these synapses, along with the measurement of cAMP concentration in different neuronal regions, this project uncovered the highly compartmentalised nature of this signalling molecule, seen to act directly at the sites of strengthening synapses. Through the optimisation of a FRET imaging system for studying activity in neuronal tissues, this project establishes a method for the future investigation of a plethora of pathways underlying the healthy functioning of the mammalian brain.
CCWI2017: F102 'A rehabilitation decision-making approach for WDNs based on extended period simulations'
Creators: name: Darvini, Giovanna
name: Ruzza, Valentina
name: Salandin, Paolo
Publisher: name: The University of Sheffield
Year: 2017
Subjects: subject: 90599 Civil Engineering not elsewhere classified
subject: FOS: Civil engineering

description: The paper addresses the relevant topic of the rehabilitation in water distribution networks (WDNs). The degradation due to ageing of the networks reduces their mechanical and hydraulic characteristics, making the pipes subject to malfunctions and failures as well as to the increase of the leakage amount. To ensure a proper service in term of quantity and quality of the water delivered to users, a suitable maintenance program must be implemented, but the associated costs are relevant, and the interventions must be planned on the basis of both technical and economic constraints. This subject is here tackled by a Monte Carlo (MC) approach, considering both the hydraulic and mechanical deterioration processes of pipes affected also by leakage, as usual in the real world. Within the MC iterations, first a probabilistic model simulates the chain of repair and failure conditions, and then the performances of the each WDN configuration is evaluated by use of an efficient pressure-driven hydraulic algorithm. The analysis of the synthetic Anytown network leads to some unexpected results in terms of pipe replacement prioritizing, and due to a different leakage percentage affecting the network, the order of priority in the pipe maintenance program may result substantially modified.
CCWI2017: F125 'The EPANET challenge'
Creators: name: Oftfeld, Avi
Publisher: name: The University of Sheffield
Year: 2017
Subjects: subject: 90599 Civil Engineering not elsewhere classified
subject: FOS: Civil engineering

description: One would rarely find anyone in the water distribution systems community that is not aware of EPANET [1]. From the early nineties, when EPANET was first introduced by the EPA, EPANET made a revolution in the water distribution systems research as well as at the practical engineering community. With numerous studies (303,000 EPANET hits on Google as of March 2, 2017) including evolutionary computational models, water quality applications, real time operation, and much more. Nothing in this professional world would have been looked alike without EPANET. As the official development of EPANET through EPA ceased, different initiatives imitated such as the Open Water Analytics [2] and recently the Center for Infrastructure Modeling and Management [3]. The water distribution systems community is now faced with a big challenge on how the future of EPANET should look like. This is a foremost challenge which goes far beyond the technical issues of a new graphical user interface (GUI) that involves technical fixes, or a more convenient framework to work with EPANET. This paper and talk will cover the author view on where EPANET should evolve from here. There should be very careful thinking on where this huge EPANET ship should sale.
Development and application of chiral analytical methods for metabolic profiling
Creators: name: Jeyapalan, Senthuran
Publisher: name: Imperial College London
Year: 2015

description: Metabonomics utilises high resolution analytical platforms to generate spectroscopic profiles that are rich in latent biological information. At present, the two principal analytical platforms used routinely in metabonomic studies are nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). While these analytical methods in their current state of development in the field of metabonomics give broad coverage across multiple chemical classes, none report sufficiently well, if at all, on the absolute configuration of chiral molecules. As a consequence of the stereospecificity present in biological systems, a very large number of biologically active molecules exhibit chirality. Therefore, an important aspect of the metabolome remains largely unexplored by current metabonomic analytical platforms. Current enantioselective methods exist, but these are largely unsuitable for multi-analyte measurements. The work in this thesis addresses the need for appropriate chiral analytical methods for metabolic profiling. The aim was to develop a practical, fit-for-purpose chiral analytical method that will report simultaneously on numerous endogenous metabolites by untargeted or widely targeted analysis, and importantly, could be aligned with existing analytical workflows. Initial evaluation of an NMR spectroscopic approach using chiral solvating agents concluded that additional spectral complexity and interaction-induced internal reference compound chemical shift instability would prohibit efficient chiral profiling in a metabonomics workflow. An existing targeted MS-based assay for enantioselective separation of amino acids was selected for optimisation and further development. Focused analyses were performed to characterise its performance in the differentiation of individual pairs of enantiomers, and subsequently expanded, first to cover the panel of proteinogenic amino acids, and secondly to other detectable metabolites. Each stage of assay optimisation incorporated an evaluation in a representative set of samples and was able to provide highly relevant biological information that would not be accessible using current achiral metabonomic methods. Further work to expand the number of detectable metabolites and quantitative nature of the assay are discussed.
Thermolab: A Thermodynamics Laboratory for Nonlinear Transport Processes in Open Systems
Creators: name: Vrijmoed, Johannes Christiaan
name: Podladchikov, Y. Y.
Publisher: name: Freie Universität Berlin
Year: 2022
Subjects: subject: thermodynamics
subject: thermolab
subject: Gibbs energy
subject: MATLAB
subject: solution models
subject: reactive transport
subject: nonlinear diffusion
subject: 500 Naturwissenschaften und Mathematik::550 Geowissenschaften, Geologie::550 Geowissenschaften

description: We developed a numerical thermodynamics laboratory called “Thermolab” to study the effects of the thermodynamic behavior of nonideal solution models on reactive transport processes in open systems. The equations of the state of internally consistent thermodynamic data sets are implemented in MATLAB functions and form the basis for calculating Gibbs energy. A linear algebraic approach is used in Thermolab to compute Gibbs energy of mixing for multicomponent phases to study the impact of the nonideality of solution models on transport processes. The Gibbs energies are benchmarked with experimental data, phase diagrams, and other thermodynamic software. Constrained Gibbs minimization is exemplified with MATLAB codes and iterative refinement of composition of mixtures may be used to increase precision and accuracy. All needed transport variables such as densities, phase compositions, and chemical potentials are obtained from Gibbs energy of the stable phases after the minimization in Thermolab. We demonstrate the use of precomputed local equilibrium data obtained with Thermolab in reactive transport models. In reactive fluid flow the shape and the velocity of the reaction front vary depending on the nonlinearity of the partitioning of a component in fluid and solid. We argue that nonideality of solution models has to be taken into account and further explored in reactive transport models. Thermolab Gibbs energies can be used in Cahn-Hilliard models for nonlinear diffusion and phase growth. This presents a transient process toward equilibrium and avoids computational problems arising during precomputing of equilibrium data.
CCWI2017: F119 'WDNs Calibration Using k-means Algorithm for Pipes Clustering and a Hybrid Model for Optimization'
Creators: name: Freitas, Rodrigo
name: Brentan, Bruno Melo
name: Lima, Gustavo Meirelles
name: Edevar Luvizotto Junior
Publisher: name: The University of Sheffield
Year: 2017
Subjects: subject: 90599 Civil Engineering not elsewhere classified
subject: FOS: Civil engineering

description: The modelling of Water Distribution Networks (WDNs) is an important issue for an efficient operation of water systems. The hydraulic simulations are used to establish the optimal conditions for pumps and valves, helping stakeholders to manage the systems. A reliable model should guarantee the minimal uncertain becoming the simulations the most real as possible. The calibration processes is used to reduce the uncertainties associated to pipe roughness and nodal demand, pipe status or leakage flow. Due to the high degrees of freedom surrounding this process, the improvement of available information of the hydraulic state of the network and the reduction of parameters to be calibrated can conduct for more reliable calibrated model. In this sense, this work present a hybrid calibration method, consisting in three stages defined as grouping pipes with k- means algorithms, pressure estimation with artificial neural networks (ANN) and an optimization process using particle swarm optimization (PSO) algorithms. A comparison between the classical approaches for roughness calibration is presented, reinforcing the improvement of the calibration process through the uncertain reduction.
Population genomics and epidemiology of Schistosoma mansoni
Creators: name: Crellen, Thomas
Publisher: name: Imperial College London
Year: 2017

description: Schistosoma mansoni is a metazoan parasite that infects millions of people across the developing world. I applied coalescence models to genome-wide single nucleotide polymorphisms (SNPs) from ten global isolates of S. mansoni and an isolate of the closely related Schistosoma rodhaini to infer the dates of: i) the speciation between S. mansoni and S. rodhaini; ii) the spread of S. mansoni across sub-Saharan Africa; and iii) the migration to the New World. Further, I used this sequence data to document signatures of directional selection between S. mansoni and S. rodhaini to uncover genes involved in host adaptation and under balancing selection in S. mansoni. I conducted a field study in Uganda to collect epidemiological data from primary schools that had been subject to contrasting intensities and durations of Mass Drug Administration (MDA). Children in endemic areas were examined for S. mansoni up to three days before and after treatment with praziquantel. I fitted a mixed-effects model to the egg count data and found that individuals from schools that were treated most intensively had a lower estimated mean egg reduction rate compared with individuals from less intensively treated schools, suggesting that more rounds of MDA may be resulting in S. mansoni parasites that are better tolerating anthelmintic treatment. Finally, I collected S. mansoni miracidia from patients in Uganda and developed a novel method for generating whole-genome sequences. In total, 213 miracidia from 35 patients were sequenced. Using a dataset of 5.4 million SNPs, I documented the population structure, characterised regions of the genome under selection and associated SNPs against the clearance phenotype. I uncovered the strongest signal of selection and the highest association with host clearance phenotype in a region at the beginning of chromosome 2 that contains two calcium channels; variants in this region may therefore be underlying the observed reduction in praziquantel efficacy.
Sputum viability microscopy for tuberculosis
Creators: name: Datta, Sumona
Publisher: name: Imperial College London
Year: 2021

description: Introduction. Sputum microscopy is the most frequently used tuberculosis laboratory test, but poorly assesses infectiousness and treatment response. The viability stain fluorescein diacetate (FDA) identifies metabolically active cells. Objective. To optimise sputum microscopy for predicting tuberculosis infectiousness and treatment outcome. Foundations. FDA sputum microscopy rapidly indicated the concentration of Mycobacterium tuberculosis that had not been sterilised by boiling and that was culturable. A cohort of 35 patients had FDA microscopy performed on their pre-treatment sputum. Lower FDA microscopy results predicted higher risk of tuberculosis disease in their 209 household contacts (adjusted hazard ratio=3.9, p=0.02). During the first 9 days of first-line therapy, these 35 patients had FDA microscopy on repeated sputum samples that rapidly differentiated patients with drug-susceptible tuberculosis from those with multi-drug resistant tuberculosis (p<0.001). Refinement. To optimise sputum collection for programmatic use, a network meta-analysis of 23 studies demonstrated that pooled sputum, as used in the foundation studies, had similar performance to more easily collected, instructed on-demand “spot” sputum collection (p=1.0). FDA microscopy was optimised for use in basic clinical laboratories. This replaced potentially biohazardous and expensive steps with more practicable alternatives. Evaluation. These refined protocols were used to collect pre-treatment sputum samples from 978 patients. Higher mycobacterial concentrations assessed by culture, PCR, conventional or FDA microscopy all predicted greater risk of tuberculosis disease in their 4311 household contacts (p<0.0001), with concordance (C)-statistics between 58-62%. Paired samples, pre-treatment and after 14 days of tuberculosis treatment, were collected from 384 patients. An alert FDA microscopy result at 14 days of treatment predicted adverse treatment outcomes (relative risk=3.0, p<0.0001), and performed better than currently used prognostic markers with 42% sensitivity and 85% specificity. Conclusion. After methodological optimisation, FDA microscopy predicted patient infectiousness and treatment outcome with similar or greater reliability than currently used laboratory tests.
Access to primary health care in England: policy, theory, and evidence
Creators: name: Cowling, Thomas Edward
Publisher: name: Imperial College London
Year: 2016

description: Background: The U.K. Government plans to improve access to general practice services in England, partly by extending the opening hours of these services. The Government expects this to enhance patient experience and reduce use of emergency hospital services. The thesis aims to provide empirical evidence relevant to these policy expectations. Methods: Three observational studies of a cross-sectional questionnaire-based survey—the GP Patient Survey—from 2011-12 to 2013-14 (2,912,535 respondents aged ≥18 years old and registered to 8,289 general practices in England). Respondent-level data were deterministically linked at the practice level to Hospital Episode Statistics Accident and Emergency (A&E) and Inpatient data and to routine data on practice characteristics. Multivariable regression estimated associations between: (1) participation in the Extended Hours Access Scheme and patient experience; (2) several patient experience measures; and (3) patient experience and rates of A&E visits and emergency hospital admissions. Results: Most patients were very (40.0%) or fairly (42.3%) satisfied with the opening hours of their practices; results were similar for experience of making an appointment and overall experience. Practices that participated in the Extended Hours Access Scheme had greater adjusted mean values of these measures than non-participants, but the mean differences were small (≤1.25 on 0-100 scales). Overall experience was most strongly associated with doctor interpersonal quality of care (standardised coefficient=0.38; 95% CI: 0.38 to 0.38). A standard deviation increase in the practice-level mean experience of making an appointment predicted a 2.7% decrease (rate ratio=0.973; 95% CI: 0.966 to 0.979) in A&E visit rates and a 1.7% decrease (rate ratio=0.983; 95% CI: 0.978 to 0.988) in emergency admission rates. Conclusions: Changes to opening hours under existing policies are unlikely to improve patient experience of general practice substantially. Realistic short-term improvements in experience would likely have modest effects on use of emergency hospital services.
Η επίδραση της χρήσης νέου πληροφοριακού συστήματος στην αποδοτικότητα της επιχείρησης
Creators: name: Σιρμανίτσα, Μαρία Λεωνίδα
Publisher: name: Aristotle University of Thessaloniki
Year: 2023
Subjects: Πληροφοριακό σύστημα
Αποδοτικότητα Επιχειρήσεων
Παράγοντες
Information system
Business efficiency
Factors

description: Η παρούσα εργασία ασχολείται με την επίδραση της χρήσης νέου πληροφοριακού συστήματος στην αποδοτικότητα των επιχειρήσεων. Αρχικά , στην εργασία γίνεται αναφορά στην έννοια της επιχειρηματικής απόδοσης και στα μέτρα επιχειρηματικής απόδοσης. Ακολουθεί αναφορά στα πληροφοριακά συστήματα , τους τύπους και στις εφαρμογές τους , ενώ το θεωρητικό μέρος ολοκληρώνεται με αναφορά στη σχέση μεταξύ επιχειρηματικής απόδοσης και χρήσης πληροφοριακών συστημάτων. Στη συνέχεια , πραγματοποιείται έρευνα σε εκπροσώπους επιχειρήσεων που δραστηριοποιούνται στην Ελλάδα με σκοπό να διερευνηθεί η επίδραση της χρήσης νέου πληροφοριακού συστήματος στην αποδοτικότητα των επιχειρήσεων. Πιο συγκεκριμένα , διερευνάται η εφαρμογή τεχνολογίας εργασιών , η ποιότητα πληροφοριών , η αντιληπτή χρησιμότητα και ευκολία χρήσης , η ποιότητα συστήματος , η απόδοση χρήστη , η αποτελεσματικότητα και δημιουργικότητα των πληροφοριακών συστημάτων των επιχειρήσεων. Μέσα από την έρευνα αναδεικνύεται ότι ο πιο σημαντικός παράγοντας που επηρεάζει την απόδοση των χρηστών είναι η αντιληπτή χρησιμότητα ακολουθούμενη από την ποιότητα του συστήματος. Η μελέτη παρέχει μια νέα βάση και εφιστά την προσοχή στην ακαδημαϊκή έρευνα που σχετίζεται με τις επιπτώσεις των πληροφοριακών συστημάτων και συμβάλλει στη βελτίωση της απόδοσης των χρηστών.
description: This paper deals with the effect of the use of a new information system on business efficiency. First , the paper refers to the concept of business performance and measures of business performance. This is followed by a reference to information systems , their types and applications , while the theoretical part concludes with a reference to the relationship between business performance and the use of information systems. Then , a survey is carried out among representatives of companies operating in Greece in order to investigate the effect of the use of a new information system on the efficiency of the companies. More specifically , the application of task technology , information quality , perceived usefulness and ease of use , system quality , user performance , efficiency and creativity of business information systems are investigated. The research shows that the most important factor affecting user performance is perceived usefulness followed by system quality. The study provides a new basis and draws attention to academic research related to the effects of information systems and contributing to the improvement of user performance.
CCWI2017: F67 'Hydraulic reliability analysis of a real network with remotely real- time controlled pressure control valves'
Creators: name: Laucelli, Daniele B.
name: Berardi, Luigi
name: Simone, Antonietta
name: Raspati, Gema
name: Ugarelli, Rita Maria
name: Giustolisi, Orazio
Publisher: name: The University of Sheffield
Year: 2017
Subjects: subject: 90599 Civil Engineering not elsewhere classified
subject: FOS: Civil engineering

description: The paper considers a real water distribution network, where current pressure control strategies exploit classical pressure control valves (PCVs). A previous study identified alternative pressure control strategies exploiting remote real time controlled pressure control valves (RRTC PCVs) together with existing classic ones, aimed at reducing background leakages. The proposed analysis relates to the hydraulic reliability of the system accounting for RRTC PCVs compared to the classic PCVs (already installed). The analysis also assumes fire protection requirements, statistical increase of customer demands and the increase of pipes deterioration (background leakages and pipe roughness). The hydraulic reliability analysis is part of the Management module of the WDNetXL system and is based on advanced hydraulic modelling, including pressure-dependent water demand components (e.g., background leakages), classic PCV and RRTC-PCVs as well as any hydraulic control device (pumps, directional valves) that might change WDN topology during the simulation.
Exploring the role of dopamine neurons in salt intake
Creators: name: Sandhu, Eleanor Clotilde
Publisher: name: Imperial College London
Year: 2016

description: Sodium is an essential element, but in the modern world average salt intake is too high and this is associated with a significant disease burden. In most mammals, depletion of salt leads to a profound behavioural change. This is termed salt appetite. The components of salt appetite are motivation for, ingestion of and enjoyment for hypertonic saline (which is aversive in the salt replete state). Deciphering the neuronal circuits that drive salt seeking behaviour may enable possible future manipulation of pathological salt appetite. Ventral tegmental area (VTA) dopamine neurons play key roles in motivated behaviours. I therefore hypothesise that the mesolimbic dopamine system is an essential component of the circuits driving salt seeking behaviour. To test this idea I studied the effect that manipulation of dopamine neuron activity has on salt appetite. My first step required the establishment of a reliable salt appetite in mice. To achieve this I used a combination of low salt feed and furosemide-induced natriuresis. I quantified the appetite for salt by measuring the intake of salt jellies of varying concentrations in a canteen setup. To control the firing rate of the dopamine neurons I have used optogenetics and chemogenetics. Strikingly, optogenetic excitation of dopamine neurons decreased salt intake in a rapid and reversible manner, despite a strong salt appetite. Importantly, optogenetic stimulation was not aversive, did not induce hyperactivity, and did not interfere with salt concentration preferences when there was no appetite. Optogenetic inhibition, chemogenetic excitation, and chemogenetic inhibition experiments suggested that a ‘burst-like’ pattern of excitation was important to the reduction in salt intake. In addition, optogenetic excitation of dopamine neurons reduced consumption of sucrose following an overnight fast, indicating a more general role of VTA dopamine neuron excitation in suppressing appetite.
Theory and simulation of moiré graphene multilayers
Creators: name: Goodwin, Zachary A H
Publisher: name: Imperial College London
Year: 2021

description: Graphene has been hailed as a material which is going to revolutionise myriad technologies due to its extraordinary stability, mechanical strength yet flexibility, and remarkable transport properties. Furthermore, it was recently discovered that if two graphene layers are stacked and twisted relative to one another, referred to as twisted bilayer graphene (tBLG), correlated insulating states and superconductivity are observed, even though graphene does not intrinsically exhibit these properties. These phases only emerge at twist angles close to the "magic angle" of 1.1 degrees, and by tuning the temperature and doping level, the system can undergo electronic phase transitions between these states. I studied electron interactions and electronic screening in tBLG and other moiré graphene multilayers. In the absence of external and internal electronic screening, I found the on-site Hubbard parameter of the flat bands of tBLG scales linearly with twist angle. Upon considering internal screening, this linear scaling breaks down, where the Hubbard interaction energy decreases more rapidly towards the magic angle owing to increased screening. Moreover, external screening, from proximity to metallic gates which dope tBLG, was found to substantially affect these Hubbard interactions, owing to the moiré length scale of the magic-angle being comparable to the distance to these metallic gates. For a sufficiently small separation to these gates, I predicted that the correlated insulating states should be screened-out and the superconducting phase should be stabilised. Long-ranged Hartree interactions were found to induced doping-dependent band-flattening in tBLG that I predicted to increase the magic-angle range of tBLG. For moiré graphene multilayers, the role of these Hartree interactions were found to sensitively depend on the stacking sequence of the structure: systems with alternating twist angles have similar interaction-driven band flattening, but systems where there are also adjacent layers that are aligned have no such interaction-driven band flattening.
CCWI2017: F37 'On the Solvability of the Pressure Driven Hydraulic Steady-State Equations Considering Feedback-Control Devices'
Creators: name: Deuerlein, Jochen
name: Piller, Olivier
name: Parisini, Fabrizio
name: Simpson, Angus R.
name: Sylvan Elhay
Publisher: name: The University of Sheffield
Year: 2017
Subjects: subject: 90599 Civil Engineering not elsewhere classified
subject: FOS: Civil engineering

description: Water supply networks (WSNs) represent an important part of urban technical infrastructure. Recently, the resilience of water distribution networks facing different physical and cyber threats has gained increasing attention. In order to improve the operation of complex water distribution systems under both, extreme and normal hydraulic conditions, mathematical simulation models are indispensable tools for engineers, network planners, network operators and decision makers. Especially, in the case of extremely disruptive events that might be caused by natural hazards or deliberate malevolent attacks by humans, the proper operation of the system for maintaining the supply of drinking water to at least parts of the population is a very challenging task. Resilient behaviour can be reached only by adaptive system operation including isolation of parts of the network and control of pressure and flows in the system. For that purpose, different kinds of control devices are used that may be remotely controlled or which are operated in the field. Existing hydraulic simulation software often fails to calculate reliable results for systems under control and pressure insufficiency. A mathematical framework for the simulation of the steady-state flow in reticulation water supply networks with special consideration of feedback control devices and pressure dependent demands is proposed in this paper. First, the importance of the steady-state calculation in the face of disruptive events is stressed and a brief review of synthetic and analytical methods for the hydraulic steady- state calculation is given. In this paper, the well-known content model is extended by the content of pressure dependent outflows. The nonlinear consumption functions in combination with linear inequality constraints (box constraints) replace the constant demands of demand driven analysis. It is also shown that the range of solvable problems in combination with flow control devices is enlarged by the relaxation of fixed demands.
CCWI2017: F18 'A Dynamic Model for Smart Water Distribution Networks'
Creators: name: Kaltenbacher, Stefan
name: Steffelbauer, David B.
name: Cattani, Marco
name: Horn, Martin
name: Hanusch, Daniela Fuchs-
name: Römer, Kay
Publisher: name: The University of Sheffield
Year: 2017
Subjects: subject: 90599 Civil Engineering not elsewhere classified
subject: FOS: Civil engineering

description: While background leakages accounting for substantial water losses in supply networks remain unde- tectable, human reaction to even visible pipe bursts is insufficiently slow. We lose precious time in which not only water losses but severe damage to the surrounding infrastructure could be prevented. These leakages can often be identified only during the minimum night flow and so repair work is delayed by days, causing intermittent water supply and outages. Increasing costs and the importance to ensure supply security require further measures. Therefore, the application of holistic algorithms controlling proportional valves and pumps allows to act instantaneously on failures by isolating affected pipe sections and by reducing the pressure in that region. With the target to apply classical control theory and yet avoid too complex formulations, this paper presents a dynamic model using no more parameters than a typical, steady-state EPANET model. By means of a sophisticated network description, we modify the rigid water column theory in terms of pressure-driven demands. Other than traditional methods, this approach enables nodal consumptions to dynamically change inner system states such as pressure or flow values. Within this method, the nodal elevation undergoes proper treatment in the model equations and further ensures that pressure values will not become negative as one may have experienced in EPANET.
Investigating sepsis immunomodulation and the role of vasopressor therapies using monocyte functional assays
Creators: name: Davies, Roger
Publisher: name: Imperial College London
Year: 2021

description: In sepsis, monocytes exhibit the differential immune response states of ‘priming’ (increased responsiveness to secondary stimuli) and ‘deactivation’ (reduced responsiveness, depressed expression of HLA-DR and CD86, increased PDL-1), which may reflect the opposing hyperinflammatory and immune-suppressive systemic conditions. In an era where the number and phenotype of circulating leucocytes are used to guide sepsis immune therapy investigation, there is debate as to whether sepsis immunity is differentially regulated within the blood and tissue compartments of the body. Adding to this uncertainty is the fact that core support therapies, such as vasopressor resuscitation, may have an immunomodulatory effect during sepsis. We hypothesised that monocytes undergo trans-endothelial reprogramming during migration between vascular and tissue compartments and that this is a crucial determinant of sepsis immunity and its clinical monitoring. Further, we hypothesised that noradrenaline and vasopressin have a role in the functional and phenotypic modification of monocytes during sepsis. Our aims were to 1) develop an in-vitro model of priming and deactivation using healthy volunteer (HV) monocytes; 2) to test the direct effects of noradrenaline and vasopressin on monocytes in comparison to sera from the VAsopressin versus Noradrenaline as Initial therapy in Septic sHock (VANISH) trial; 3) develop a human lung microvascular endothelial cell (HLMVEC) transwell model of monocyte migration and associated phenotypic changes during sepsis. The major findings of this work were that in combination vasopressin and noradrenaline suppressed LPS-induced TNF release in non-pretreated and primed HV monocytes. In contrast, when HV monocytes were incubated with VANISH patient sera we found no difference in surface marker expression or LPS-induced TNF release. Conditioning of monocytes with vasopressin or noradrenaline was found to enhance their migration in an uncoated transwell assay. Lastly, we successfully developed an HLMVEC-coated transwell migration assay able to detect changes in pre- and post-migration monocyte phenotype.
Design tools for the optimal exploitation of tidal-stream renewable energy
Creators: name: Goss, Zoe Louise
Publisher: name: Imperial College London
Year: 2021

description: Tidal stream power generation is attractive for a number of reasons. However, this will only be deployed on a commercial scale, in arrays of tens to hundreds of turbines, if these arrays can be shown to be viable from economic, engineering and environmental perspectives. With limited experience from real arrays and constraints on the size of lab-based experiments, advanced numerical tools are needed to both predict and maximise power yield. These tools can be used to prove viability of new sites and aid array design in this fledgling industry. Holistic economic models are needed to aid the industry's move from demonstrator arrays to commercially sized arrays that can compete at a lower subsidy level. This thesis investigates economic models for evaluating the performance of arrays and different cost reduction methods, which may help to bring the cost of tidal energy in line with other sustainable energy sources. A methodology to optimise array design with respect to complex economic models is presented. This method builds an emulator of the trade-off curve between total yield and number of turbines, generated from a computationally expensive set of optimisation loops. It enables far more robust analysis of the implications of changes to the economic models than is possible through direct optimisation alone. A tool is created to investigate further cost reductions that could be obtained through the assessment of a range of different turbine rotor sizes and rated capacities, as well as other array design specifications. The tool is used to make preliminary assessments of array design choices, while adhering to practical constraints such as sea bed depth and steepness, along with legal constraints such as consents on the number of turbines and spacing between them. The tool developed can be applied to early-stage assessments and narrowing down the scope of array design specifications.