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.
Mostrando recursos 61 - 80 de 343,438
Reciprocal associations between smoking cessation and depression in older smokers: findings from the English Longitudinal Study of Ageing (ELSA) - Shahab, L; Gilchrist, G; Hagger-Johnson, G; Shankar, A; West, E; West, R
Background: Depression is a particular problem in older people and it is important to know how it affects and is affected by smoking cessation. Aims: To identify reciprocal, longitudinal relationships between smoking cessation and depression among older smokers. Methods: Across four waves, covering six years (2002–2008), changes in smoking status and depression, measured using the 8–item Centre for Epidemiologic Studies Depression Scale, were assessed among recent ex-smokers and smokers (N=2,375) in the English Longitudinal Study of Ageing. Results: In latent growth curve analysis, smoking at baseline predicted depression caseness longitudinally and vice versa. When both processes were modelled concurrently, depression...
Energy efficiency and time charter rates: Energy efficiency savings recovered by ship owners in the Panamax market - Agnolucci, P; Smith, T; Rehmatulla, N
This paper presents the first analysis on how financial savings arising from energy efficient ships are allocated between owners and those hiring the ships. This as an important undertaking as allocation of financial savings is expected to have an impact on the incentives faced by ship owners to invest in more energy efficient vessels. We focus on the dry bulk Panamax segment as it contributes to around 50 Mt (5%) of total CO2 emissions from shipping in 2007 and therefore its importance in terms of environmental impact should not be neglected. The time charter market represents a classical example of...
Be prepared: The EMV pre-play attack - Bond, M; Choudary, O; Murdoch, SJ; Skorobogatov, S; Anderson, R
EMV, also known as “Chip and PIN”, is the leading system for smartcard-based payments worldwide; it is widely deployed in Europe and is starting to be introduced in the USA too. It replaces the familiar mag-strip cards with chip cards. A cryptographic protocol is executed between a chip card and bank servers based on a message authentication code (MAC) over transaction data, including a nonce called the unpredictable number. We discovered two protocol flaws: first, the lack of a terminal ID to identify involved parties, and second that the nonce is not generated by the relying party. Together, these make...
Contribution of respiratory tract infections to child deaths: a data linkage study. - Hardelid, P; Dattani, N; Cortina-Borja, M; Gilbert, R
Respiratory tract infections (RTIs) are an important cause of death in children, and often contribute to the terminal decline in children with chronic conditions. RTIs are often underrecorded as the underlying cause of death; therefore the overall contribution of RTIs to child deaths and the potential preventability of RTI-related deaths have not been adequately quantified.
Causal modelling of evoked brain responses. - Isabel Figueiredo Garrido, M.
The aim of this thesis was to test predictive coding as a model of cortical organization and function using a specific brain response, the mismatch negativity (MMN), and a novel tool for connectivity analysis, dynamic causal modelling (DCM). Predictive coding models state that the brain perceives and makes inferences about the world by recursively updating predictions about sensory input. Thus, perception would result from comparing bottom-up input from the environment with top-down predictions. The generation of the MMN, an event- related response elicited by violations in the regularity of a structured auditory sequence, has been discussed extensively in the literature....
MRI investigations into the pilocarpine model of status epilepticus. - Choy, M.
Status epilepticus (SE) is a medical neurological emergency and may cause brain injury associated with epilepsy and cognitive decline. Evidence suggests that the hippocampus is particularly vulnerable to injury from SE and that the resulting hippocampal injury has been hypothesised to continue to evolve on to mesial temporal sclerosis associated temporal lobe epilepsy (MTS-TLE). This form of epilepsy is particularly difficult to treat with current medical therapies, and thus it is the most common epilepsy that requires surgical intervention. Therefore understanding the relationships between SE, hippocampal injury and MTS-TLE may provide the basis for development of novel therapies for treating...
Studies of adeno-associated virus-induced DNA damage responses. - Garner, E.A.
Adeno-associated virus (AAV) infection triggers a DNA damage response in the cell. This response is not induced by viral proteins but by the structure of AAV ssDNA being recognized by the cell as damaged DNA. The consequence of this is the killing of cells lacking p53 activity. We have observed that cells that lack p21 or pRb activity are also sensitive to AAV-induced cell death. We report that cells respond to AAV infection by activating two DNA damage-signaling cascades. The first activates the p84N5 protein, which in turn activates caspase-6, leading to cell death. The second cascade activates the p53-21-pRb...
Detection, monitoring & clonal characterisation of human cytomegalovirus specific CD8+ T cells in hematopoietic stem cell transplant patients. - Giest, S.
The human cytomegalovirus (CMV) can cause significant morbidity and mortality in haematopoietic stem cell transplant (HSCT) patients. The immunosuppressed state of the hosts facilitates dissemination of the virus and disease. In contrast, CD8+ T cells in healthy individuals control viral dissemination and maintain a balance between antiviral host defence and replication of the virus that leads to viral latency with sporadic, harmless reactivations. Current pharmacological intervention in the HSCT setting is associated with significant toxicity and is counteracted by the occurrence of resistant viral strains. Alternative approaches, such as adoptive therapy of CMV specific CD8+ T cells are of great...
Preliminary studies in imaging neuronal depolarization in the brain with electrical or magnetic detection impedance tomography. - Gilad, O.
Electrical impedance Tomography (EIT) is a novel medical imaging method which has the potential to provide the revolutionary advance of a method to image fast neural activity non-invasively. by imaging electrical impedance changes over milliseconds which occur when neuronal ion channels open during activity. These changes have been estimated to be c.1% locally in cerebral cortex, if measured with applied current below 100Hz. The purpose of this work was to determine if such changes could be reproducibly recorded in humans non invasive First, a novel recessed electrode was designed and tested to determine to enable a maximal current of 1mA...
Immunity induced by a broad class of inorganic crystalline materials is directly controlled by their chemistry - Williams, GR; Fierens, K; Preston, SG; Lunn, D; Rysnik, O; De Prijck, S; Kool, M; Buckley, HC; Lambrecht, BN; O'Hare, D; Austyn, JM
There is currently no paradigm in immunology that enables an accurate prediction of how the immune system will respond to any given agent. Here we show that the immunological responses induced by members of a broad class of inorganic crystalline materials are controlled purely by their physicochemical properties in a highly predictable manner. We show that structurally and chemically homogeneous layered double hydroxides (LDHs) can elicit diverse human dendritic cell responses in vitro. Using a systems vaccinology approach, we find that every measured response can be modeled using a subset of just three physical and chemical properties for all compounds...
Registration of MR and CT images for skull base surgery using point-like anatomical features. - Hill, DL; Hawkes, DJ; Crossman, JE; Gleeson, MJ; Cox, TC; Bracey, EE; Strong, AJ; Graves, P
We have developed a registration technique for combining magnetic resonance imaging (MRI) and computed tomography (CT) images of the skull base for use in surgical planning. The technique is based on user identification of point-like landmarks visible in both modalities. The combination of images involves a small amount of expert interaction, is relatively quick and preliminary evaluation indicates that it is accurate to within 1.5 mm. Registered or fused images can be viewed either on an image processing workstation, or fused images can be printed onto conventional film for convenience in clinical use. We present one patient in order to...
Feasibility study of magnetic resonance imaging-guided intranasal flexible microendoscopy. - Hill, DL; Langsaeter, LA; Poynter-Smith, PN; Emery, CL; Summers, PE; Keevil, SF; Pracy, JP; Walsh, R; Hawkes, DJ; Gleeson, MJ
Interventional magnetic resonance imaging (MRI) offers potential advantages over conventional interventional modalities such as X-ray fluoroscopy, ultrasonography, and computed tomography (CT). In particular, it does not use ionizing radiation, can provide high-quality images, and allows acquisition of oblique sections. We have carried out a feasibility study on the use of interventional MRI to track a flexible microendoscope in the paranasal sinuses. In this cadaver study, high-speed MRI was used to track a passive marker attached to the end of the endoscope. Automatic image registration algorithms were used to transfer the coordinates of the endoscope tip into the preoperative MRI and...
Augmentation of reality using an operating microscope for otolaryngology and neurosurgical guidance. - Edwards, PJ; Hawkes, DJ; Hill, DL; Jewell, D; Spink, R; Strong, A; Gleeson, M
The operating microscope is an integral part of many neurosurgery and otolaryngology procedures; the surgeon often uses the microscopic view for a large portion of the operation. Information from preoperative radiological images is often viewed only on X-ray films. The surgeon then has the difficult task of relating this information to the appearance of the surgical view. Image guidance techniques attempt to relate these two sets of information by registering the patient in the operating room to preoperative images using locating devices. Conventionally, image data are presented on a computer monitor, which requires the surgeon to look away from the...