UCL University College London Eprints
UCL Eprints collects the work of UCL researchers and makes it freely available over the web, helping the worldwide scholarly community to discover UCL research. Institutional repositories like UCL Eprints complement the traditional academic publishing and scholarly communications processes. They raise the visibility of research and help to maximise its impact. UCL researchers are encouraged to deposit a copy of each journal article, conference paper, working paper, and any other research output, in the UCL Eprints at the earliest opportunity, ensuring that their research reaches as wide an audience as possible.
Novel encapsulation systems and processes for overcoming the challenges of polypharmacy. - Orlu-Gul, M; Topcu, AA; Shams, T; Mahalingam, S; Edirisinghe, M
The encapsulation process has been studied to develop smart drug delivery systems for decades. In particular, micro-encapsulation and nano-encapsulation approaches have gained wide interest in the development of particulate drug delivery and achieved progress in specialties such as nano-medicine. Encapsulation technologies have evolved through various platforms including emulsion solvent evaporation, spray drying and polymer conjugation. Among current encapsulation methods, electrohydrodynamic and microfluidic processes stand out by enabling the making of formulations with uniform shape and nanoscale size. Pressurized gyration is a new method of combining rotation and controlled pressure to produce encapsulated structures of various morphologies. In this review we...
Exploring possible transition pathways for hydrogen energy: A hybrid approach using socio-technical scenarios and energy system modelling - McDowall, W
Hydrogen remains an important option for long-term decarbonisation of energy and transport systems. However, studying the possible transition paths and development prospects for a hydrogen energy system is challenging. The long-term nature of technological transitions inevitably means profound uncertainties, diverging perspectives and contested priorities. Both modelling approaches and narrative storyline scenarios are widely used to explore the possible future of hydrogen energy, but each approach has shortcomings.This paper presents a hybrid approach to assessing hydrogen transitions in the UK, by confronting qualitative socio-technical scenarios with quantitative energy systems modelling, through a process of 'dialogue' between scenario and model. Three possible...
Electromagnetic characterisation of terrain for unconventional petroleum exploration - Ezeoke, M; Tong, K; Mubea, K
A method to characterize the electromagnetic (EM) signature of barefaced terrain using 3D computer electromagnetic models (CEM) for radar applications is presented. Five barefaced terrain types with different electrical, physical and chemical properties were investigated. They include both homogeneous and heterogeneous terrain types particularly beach sand, gravel and pebble acquired locally and oil sands from Nigeria. The approach develops CEMs using reflectance spectroscopy and dielectric permittivity data. First geochemical signatures were determined using reflectance spectroscopy in the Near Infrared region while dielectric properties were experimentally determined at L-, C- and X-band for multi-frequency radar. Both viscous and hard oil sand...
Can stress trigger Parkinson's disease? - Djamshidian, A; Lees, AJ
In this manuscript we summarize the role of chronic stress as a potential trigger factor for Parkinson's disease. Underlying mechanisms and stress-induced changes to the neuronal networks have been highlighted. Examples of stress induced reversible symptoms that resemble parkinsonism in humans and in animal models raise the question whether emotional stress can cause striatal degeneration in susceptible patients. A Pubmed literature review searching for the terms 'Stress', 'Distress and Parkinson's disease', 'Emotional Distress and Parkinson's disease', 'Stress and Parkinson's disease', 'Prodromal Parkinson's disease', 'Non motor symptoms and Parkinson's disease', 'Paradoxical kinesia', 'Psychogenic parkinsonism', 'Functional somatic syndromes', 'Chronic fatigue syndrome', 'Irritable...
Factors associated with parental non-adoption of infant male circumcision for HIV prevention in Sub-Saharan Africa: A systematic review and thematic synthesis - Mavhu, W; Mupambireyi, Z; Cowan, FM; Hart, G
Infant male circumcision (IMC) may be more effective at preventing HIV than adult male circumcision as the procedure is carried out before the individual becomes sexually active. Successful scale-up will depend on identifying and overcoming parental concerns that may act as barriers for IMC. We conducted a systematic review to identify qualitative studies reporting on parental reasons for non-adoption of IMC for HIV prevention in sub-Saharan Africa. Thematic synthesis was subsequently conducted. Five descriptive themes were identified; these were later condensed into two main analytical themes: "poor knowledge" and "social constructs". While barriers and motivators are to some degree context...
Towards Model-Based Diagnosis of von Willebrand Disease - Galvanin, F; Monte, A; Casonato, A; Padrini, R; Barolo, M; Bezzo, F
Abstract Von Willebrand disease (VWD) is the most common inherited coagulation disorder to be seen in humans. It originates from a deficiency and/or dysfunction of the von Willebrand factor (VWF), a large multimeric glycoprotein playing a central role in the hemostasis process. Diagnosing VWD may be complicated because of the heterogeneous nature of the disorder. A new mechanistic model of VWD, identified from clinical data, is presented in this paper. The model allows for the automatic detection of VWD variants, elucidating the critical pathways involved in the disease recognition and characterisation.
Monolithically integrated optical phase lock loop for microwave photonics - Balakier, K; Fice, MJ; Ponnampalam, L; Seeds, AJ; Renaud, CC
We present a review of the critical design aspects of monolithically integrated optical phase lock loops (OPLLs). OPLL design procedures and OPLL parameters are discussed. A technique to evaluate the gain of the closed loop operating system is introduced and experimentally validated for the first time. A dual-OPLL system, when synchronised to an optical frequency comb generator without any prior filtering of the comb lines, allows generation of high spectral purity signals at any desired frequency from several GHz up to THz range. Heterodyne phase locking was achieved at a continuously tuneable offset frequency between 2 and 6 GHz. Thanks...
Microwave photonic integrated circuits for millimeter-wave wireless communications - Carpintero, G; Guzmán, RC; Jimenez, A; Balakier, K; Fice, MJ; Renaud, CC; Seeds, AJ; Kervella, G; Lamponi, M; Chitoui, M; Van Dijk, F; Corradi, A; Bente, EAJM; Yang, Z; Wonfor, A; Penty, RV; White, IH
This paper describes the advantages that the introduction of photonic integration technologies can bring to the development of photonic-enabled wireless communications systems operating in the millimeter wave frequency range. We present two approaches for the development of dual wavelength sources for heterodyne-based millimeter wave generation realized using active/passive photonic integration technology. One approach integrates monolithically two distributed feedback semiconductor lasers along with semiconductor optical amplifiers, wavelength combiners, electro-optic modulators and broad bandwidth photodiodes. The other uses a generic photonic integration platform, developing narrow linewidth dual wavelength lasers based on arrayed waveguide gratings. Moreover, data transmission over a wireless link at...
Environmentally induced colour change during natural degradation of selected polymers - Pastorelli, G; Cassar, M; Strlič, M; Cucci, C; Garcia, O; Piantanida, G; Elnaggar, A
The aim of this study was to examine the simultaneous effect of multiple degradation agents on selected polymer materials in natural environments, and the relative effect of atmospheric pollutants compared to other environmental parameters (heat, humidity and light). A complex exposure experiment was set up to investigate the colour change of 17 different types of polymers (cellulose carboxylate, polyamide, poly(vinyl chloride), polystyrene, polyethylene, polypropylene, polycarbonate, polyurethane, and melamine formaldehyde and phenol formaldehyde resins) in real time in different environmental conditions over a 2-year period at 11 sites across Europe and North Africa, sheltered from UV light and precipitation. Suitable environmental...
Genetic and laboratory diagnostic approach in Niemann Pick disease type C - McKay Bounford, K; Gissen, P
Niemann Pick disease type C (NP-C) is a rare autosomal recessive disorder that results from mutations in either the NPC1 or the NPC2 gene. The estimated incidence of NP-C is 1 in 120,000 live births, although the frequency of cases is higher in some isolated populations. More than 350 different NPC1 and NPC2 gene mutations have been reported in patients with confirmed diagnoses. Approximately 95 % of patients harbour mutations in NPC1, with most of the remaining patients having NPC2 mutations. The traditional methods for diagnosing patients with NP-C include histopathological analysis of bone marrow aspirate, liver and skin biopsies,...