767 research outputs found
The Learning Grid at the University of Warwick : a library innovation to support learning in higher education
Colleagues often ask, âwhat is The Learning Grid?â
and âwhy is it different?â The following article
aims to highlight the unique elements of this
library facility and also to present some of the
key areas of development that continue to evolve
since its opening in September 2004.
The Learning Grid was designed and is managed
by the University Library. This meant that the
University Librarian had direct input into the
design and concept for the space that measures
approximately 1350mÂČ. Because the space was
identified as an opportunity to provide students
at Warwick with a unique learning experience, the
need to work in collaboration with other support
services was essential in exploring the aims
and objectives of this facility, as well as its design.
Architects from MacCormack, Jamieson, Prichard
(MJP), London, were integral to the development
process, ensuring that draft designs reflected the
evolving concepts for the purpose of the space
and activities that would take place within it
Scanning laser source and scanning laser detection techniques for different surface crack geometries
Standard test samples typically contain simulated defects such as slots machined normal to the surface. However, real defects will not always propagate in this manner; for example, rolling contact fatigue on rails propagates at around 25Âș to the surface, and corrosion cracking can grow in a branched manner. Therefore, there is a need to understand how ultrasonic surface waves interact with different crack geometries. We present measurements of machined slots inclined at an angle to the surface normal, or with simple branched geometries, using laser ultrasound. Recently, Rayleigh wave enhancements observed when using the scanning laser source technique, where a generation laser is scanned along a sample, have been highlighted for their potential in detecting surface cracks. We show that the enhancement measured with laser detector scanning can give a more significant enhancement when different crack geometries are considered. We discuss the behaviour of an incident Rayleigh wave in the region of an angled defect, and consider mode-conversions which lead to a very large enhancement when the detector is close to the opening of a shallow defect. This process could be used in characterising defects, as well as being an excellent fingerprint of their presence
Non-contact ultrasonic detection of angled surface defects
Non-destructive testing is an important technique, and improvements are constantly needed. Surface defects in metals are not necessarily confined to orientations normal to the sample surface; however, much of the previous work investigating the interaction of ultrasonic surface waves with surface-breaking defects has assumed cracks inclined at 90° to the surface. This paper explores the interaction of Rayleigh waves with cracks which have a wide range of angles and depths relative to the surface, using a non-contact laser generation and detection system. Additional insight is acquired using a 3D model generated using finite element method software. A clear variation of the reflection and transmission coefficients with both crack angle and length is found, in both the out-of-plane and in-plane components. The 3D model is further used to understand the contributions of different wavemodes to B-Scans produced when scanning a sample, to enable understanding of the reflection and transmission behaviour, and help identify angled defects. Knowledge of these effects is essential to correctly gauge the severity of surface cracking
Scanning laser techniques for characterisation of different surface breaking defect geometries
Measurements using a laser scanning system consisting of a pulsed Nd:YAG laser to generate surface ultrasonic
waves and an interferometer to detect the surface displacement, are presented for different samples and defect geometries. We show, ïŹrstly, details of the interaction of Rayleigh waves in thick samples with machined slots inclined at an angle to the surface normal, or with simple branched geometries, scanning the generation source over the defect (SLLS) or scanning the detection point over the defect (SLD). Secondly, we discuss effects of Lamb waves interacting with V-shaped defects in thin samples. The results from these measurements have shown that the signal enhancement found in the near-ïŹeld in both cases can be used to position the defect and gain an idea of its geometry, and have shown this to be a suitable ïŹngerprint of the presence of the defect
Nuclear expression of Lyn, a Src family kinase member, is associated with poor prognosis in renal cancer patients
Background: 8000 cases of renal cancer are diagnosed each year in the UK, with a five-year survival rate of 50 %.
Treatment options are limited; a potential therapeutic target is the Src family kinases (SFKs). SFKs have roles in
multiple oncogenic processes and promote metastases in solid tumours. The aim of this study was to investigate
SFKs as potential therapeutic targets for clear cell renal cell carcinoma (ccRCC).
Methods: SFKs expression was assessed in a tissue microarray consisting of 192 ccRCC patients with full clinical
follow-up. SFK inhibitors, dasatinib and saracatinib, were assessed in early ccRCC cell lines, 786-O and 769-P and a
metastatic ccRCC cell line, ACHN (± Src) for effects on protein expression, apoptosis, proliferation and wound
healing.
Results: High nuclear expression of Lyn and the downstream marker of activation, paxillin, were associated with
decreased patient survival. Conversely, high cytoplasmic expression of other SFK members and downstream marker
of activation, focal adhesion kinase (FAK) were associated with increased patient survival. Treatment of non-metastatic
786-O and 769-P cells with dasatinib, dose dependently reduced SFK activation, shown via SFK (Y419) and FAK (Y861)
phosphorylation, with no effect in metastatic ACHN cells. Dasatinib also increased apoptosis, while decreasing
proliferation and migration in 786-O and 769-P cell lines, both in the presence and absence of Src protein.
Conclusions: Our data suggests that nuclear Lyn is a potential therapeutic target for ccRCC and dasatinib
affects cellular functions associated with cancer progression via a Src kinase independent mechanism
"You are just left to get on with it": qualitative study of patient and carer experiences of the transition to secondary progressive multiple sclerosis
Objectives Although the transition to secondary progressive multiple sclerosis (SPMS) is known to be a period of uncertainty for clinicians, who may find progressive disease challenging to objectively identify, little research has explored the experiences of patients and carers specifically during this transition period. Our objective was to explore what patients and their carers understand about their disease stage and describe their experiences and perspectives on the transition to SPMS.
Design Semistructured qualitative interviews and subsequent validation focus groups were analysed using inductive thematic analysis.
Setting South East Wales, UK.
Participants 20 patients with MS and 13 carers were interviewed. Eight patients and two carers participated in focus groups.
Results Four main themes around disease progression were identified. âRealisationâ describes how patients came to understand they had SPMS while âreactionâ describes their response to this realisation. The ârealitiesâ of living with SPMS, including dealing with the healthcare system during this period, were described along with âfuture challengesâ envisaged by patients and carers.
Conclusions Awareness that the transition to SPMS has occurred, and subsequent emotional reactions and coping strategies, varied widely between patients and their carers. The process of diagnosing the transition was often not transparent and some individuals wanted information to help them understand what the transition to SPMS meant for them
The effect of EMAT coil geometry on the Rayleigh wave frequency behaviour
Understanding of optimal signal generation and frequency content for electromagnetic acoustic transducers (EMATs) is key to improving their design and signal to noise ratio. Linear and meander coil designs are fairly well understood, but other designs such as racetrack or focused coils have recently been proposed. Multiple transmission racetrack coil EMATs, with focused and unfocused designs, were constructed. The optimum driving frequency for maximum detected signal was found to range between 1.1 and 1.4âŻMHz on aluminium for a 1.5âŻmm width coil. A simple analytical model based on the instantaneous velocity of a wave predicts a maximum signal at 1.44âŻMHz. Modelling the detection coil as a spatial square wave agrees with this, and predicts a general relation of f =0.761v/L between the optimum frequency f , the wave velocity v, and the coil width L. A time domain model of the detection coil predicts a 1.4-1.5âŻMHz peak for continuous wave excitation, with a frequency that decreases as the length of the wavepacket is decreased, consistent with the experimental data. Linear coil modelling using the same technique is shown to be consistent with previous work, with improving detection at lower wave frequencies, and signal minima at every integer multiple of the wavelength. Finite Element Analysis (FEA) is used to model the effects of the spatial width of the racetrack generation coil and focused geometry, and no significant difference is found between the focused and the unfocused EMAT response. This highlights the importance of designing the EMAT coil for the correct lift-off and desired frequency of operation. [Abstract copyright: Copyright © 2019 Elsevier B.V. All rights reserved.
Magnetic phase transitions in Gd64Sc36 studied using non-contact ultrasonics
The speed and attenuation of ultrasound propagation can be used to determine material properties and identify phase transitions. Standard ultrasonic contact techniques are not always convenient due to the necessity of using couplant; however, recently reliable non-contact ultrasonic techniques involving electromagnetic generation and detection of ultrasound with electromagnetic acoustic transducers (EMATs) have been developed for use on electrically conducting and/or magnetic materials. We present a detailed study of magnetic phase transitions in a single crystal sample of Gd64Sc36 magnetic alloy using contact and non-contact ultrasonic techniques for two orientations of external magnetic field. Phase diagrams are constructed based on measurements of elastic constant C33, the attenuation and the efficiency of generation when using an EMAT. The EMATs are shown to provide additional information related to the magnetic phase transitions in the studied sample, and results identify a conical helix phase in Gd64Sc36 in the magnetic field orientation
A novel FRET-based screen in high-throughput format to identify inhibitors of malarial and human glucose transporters
The glucose transporter PfHT is essential to the survival of the malaria parasite Plasmodium falciparum and has been shown to be a druggable target with high potential for pharmacological intervention. Identification of compounds against novel drug targets is crucial to combating resistance against current therapeutics. Here, we describe the development of a cell-based assay system readily adaptable to high-throughput screening that directly measures compound effects on PfHT-mediated glucose transport. Intracellular glucose concentrations are detected using a genetically encoded fluorescence resonance energy transfer (FRET)-based glucose sensor. This allows assessment of the ability of small molecules to inhibit glucose uptake with high accuracy (ZâČ factor of >0.8), thereby eliminating the need for radiolabeled substrates. Furthermore, we have adapted this assay to counterscreen PfHT hits against the human orthologues GLUT1, -2, -3, and -4. We report the identification of several hits after screening the Medicines for Malaria Venture (MMV) Malaria Box, a library of 400 compounds known to inhibit erythrocytic development of P. falciparum. Hit compounds were characterized by determining the half-maximal inhibitory concentration (IC(50)) for the uptake of radiolabeled glucose into isolated P. falciparum parasites. One of our hits, compound MMV009085, shows high potency and orthologue selectivity, thereby successfully validating our assay for antimalarial screening
Durability of reflector materials in the space environment
Various reflector configurations were flown as part of the Long Duration Exposure Facility (LDEF) A0171 experiment. These reflectors consisted of nickel substrates with aluminum, enhanced aluminum (multiple layers of aluminum and silver), silver, and silver alloy coatings with glassy ceramic overcoatings. These samples have been evaluated for changes in reflectance due to 5.8 years in the space environment. The reflector materials have also been evaluated using angstrometer, Rutherford backscattering (RBS), and electron spectroscopy for chemical analysis (ESCA) techniques
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