Tissue Doppler echocardiography for the characterisation of the hypertensive ventricle

This thesis used tissue Doppler echocardiography to characterise, in detail, left ventricular function in 1006 subjects and produced several novel findings. Firstly, transmitral Doppler had limited ability to identify impaired diastolic function in a cohort at high risk of diastolic dysfunction. Further, the Valsalva maneouvre was found to be unreliable as a discriminator in subjects with an apparently normal transmitral Doppler flow profile. Secondly, using tissue Doppler early mitral annular velocities (E'), subjects of African- Caribbean ethnicity were demonstrated to have more impaired diastolic function than populations of White European origin. Thirdly, a correlation was demonstrated between fasting plasma glucose levels and left ventricular diastolic function, supporting the concept of a 'diabetic cardiomyopathy'. Fourthly, the anti-hypertensive combination regimen atenolol+/- bendroflumethiazide was demonstrated to be associated with relatively adverse measures of diastolic function when compared to a regimen of amlodipine+/- perindopril. Finally, a large cohort of hypertensive subjects underwent echocardiography and was followed for 4.2 years. The strongest predictor of future cardiac events proved to be the subject's diastolic function, as measured using the ratio of the transmural pulsed Doppler early filling velocity (E) to the tissue Doppler early mitral annular velocity (E'). Three of the chapters in this thesis formed the basis for publications in major cardiac journals, as described at the outset of this thesis. One of the aims of this body of research was to provide further support for the inclusion of Tissue Doppler echocardiography in standard clinical echocardiographic protocols. This is now the case, with most echo labs including TDE measures in their routine studies as a result of the large body of work now existing in the literature, of which this thesis forms one small component. The non¬ invasive assessment of left atrial filling pressure using the E/E' ratio is now routinely quoted in the average echocardiographic report and the data reported in this thesis add further focused support for that strategy

Hex Player—a virtual musical controller

In this paper, we describe a playable musical interface for tablets and multi-touch tables. The interface is a generalized keyboard, inspired by the Thummer, and consists of an array of virtual buttons. On a generalized keyboard, any given interval always has the same shape (and therefore fingering); furthermore, the fingering is consistent over a broad range of tunings. Compared to a physical generalized keyboard, a virtual version has some advantages—notably, that the spatial location of the buttons can be transformed by shears and rotations, and their colouring can be changed to reflect their musical function in different scales. We exploit these flexibilities to facilitate the playing not just of conventional Western scales but also a wide variety of microtonal generalized diatonic scales known as moment of symmetry, or well-formed, scales. A user can choose such a scale, and the buttons are automatically arranged so their spatial height corresponds to their pitch, and buttons an octave apart are always vertically above each other. Furthermore, the most numerous scale steps run along rows, while buttons within the scale are light-coloured, and those outside are dark or removed. These features can aid beginners; for example, the chosen scale might be the diatonic, in which case the piano’s familiar white and black colouring of the seven diatonic and five chromatic notes is used, but only one scale fingering need ever be learned (unlike a piano where every key needs a different fingering). Alternatively, it can assist advanced composers and musicians seeking to explore the universe of unfamiliar microtonal scales

Mobile Phones, Nutrition and Agriculture in Ghana: Business Modelling Baseline Report

This is the baseline report for the business modelling analysis of the Vodafone Farmers Club, Ghana (VFC), a Value Added Service supported by a grant from the GSM Association (GSMA) as a part of the mNutrition programme. It presents a baseline description of the service and an analysis of the business models based on data available at the beginning of the mNutrition evaluation. mNutrition is a global initiative supported by DFID, organised by GSMA, and implemented by in-country mobile network operators (MNOs) to use mobile technology to improve the health and nutritional status of children and adults in low-income countries around the world. This report forms part of the evaluation of mobile based services, which draws on a number of methods and interlinked components to gather evidence about the impact of the intervention in Ghana supported by the mNutrition programme

Laser surface alloying of 316L stainless steel coated with a bioactive hydroxyapatite-titanium oxide composite.

Laser surface alloying is a powerful technique for improving the mechanical and chemical properties of engineering components. In this study, laser surface irradiation process employed in the surface modification off 316L stainless steel substrate using hydroxyapatite-titanium oxide to provide a composite ceramic layer for the suitability of applying this technology to improve the biocompatibility of medical alloys and implants. Fusion of the metal surface incorporating hydroxyapatite-titania ceramic particles using a 30 W Nd:YAG laser at different laser powers, 40, 50 and 70% power and a scan speed of 40 mm s(-1) was observed to adopt the optimum condition of ceramic deposition. Coatings were evaluated in terms of microstructure, surface morphology, composition biocompatibility using XRD, ATR-FTIR, SEM and EDS. Evaluation of the in vitro bioactivity by soaking the treated metal in SBF for 10 days showed the deposition of biomimetic apatite

Relating identifier naming flaws and code quality: An empirical study

Studies have demonstrated the importance of good identifier names to program comprehension. It is unclear, however, whether poor naming has other effects that might impact maintenance effort, e.g. on code quality. We evaluated the quality of identifier names in 8 established open source Java applications libraries, using a set of 12 identifier naming guidelines. We found statistically significant associations between flawed identifiers (i.e. violating at least one guideline) and code quality issues reported by FindBugs, a static analysis tool

Exploring the Influence of Identifier Names on Code Quality: An empirical study

Given the importance of identifier names and the value of naming conventions to program comprehension, we speculated in previous work whether a connection exists between the quality of identifier names and software quality. We found that flawed identifiers in Java classes were associated with source code found to be of low quality by static analysis. This paper extends that work in three directions. First, we show that the association also holds at the finer granularity level of Java methods. This in turn makes it possible to, secondly, apply existing method-level quality and readability metrics, and see that flawed identifiers still impact on this richer notion of code quality and comprehension. Third, we check whether the association can be used in a practical way. We adopt techniques used to evaluate medical diagnostic tests in order to identify which particular identifier naming flaws could be used as a light-weight diagnostic of potentially problematic Java source code for maintenance

Mining Java Class Naming Conventions

Class names represent the concepts implemented in object-oriented source code and are key elements in program comprehension and, thus, software maintenance. Programming conventions often state that class names should be noun-phrases, but there is little further guidance for developers on the composition of class names. Other researchers have observed that the majority of Java class identifier names are composed of one or more nouns preceded, optionally, by one or more adjectives. However, no detailed analysis of class identifier name structure has been undertaken that could be leveraged to support program comprehension activities. We investigate the lexical and syntactic composition of Java class identifier names in two ways. Firstly, as others have done for C function and Java method names, we identify conventional patterns found in the use of parts of speech. Secondly, we identify the origin of words used in class names within the name of any super class and implemented interfaces to identify patterns of class name construction related to inheritance. Through the analysis of 120,000 unique class names found in 60 open source projects we identify both common and project specific class naming conventions. We apply this knowledge in a case study of the mind-mapping tool Freemind to investigate whether class names that follow unconventional naming schemes are candidates for refactoring – either a name refactoring that conforms to established naming conventions within the code base, or refactoring of the class that results in conventionally named classes

The spectrum effect in tests for risk prediction, screening, and diagnosis.

The spectrum effect describes the variation between settings in performance of tests used to predict, screen for, and diagnose disease. In particular, the predictive use of a test may be different when it is applied in a general population rather than in the study sample in which it was first developed. This article discusses the impact of the spectrum effect on measures of test performance, and its implications for the development, evaluation, application, and implementation of such tests.JUS is supported by a National Institute of Health Research (NIHR) Clinical Lectureship. The views expressed in this publication are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. SJS is supported by the Medical Research Council www.mrc.ac.uk [Unit Programme number MC_UU_12015/1].This is the final version of the article. It first appeared from the BMJ Group via https://doi.org/10.1136/bmj.i313

Measurement of hepcidin isoforms in human serum by liquid chromatography with high resolution mass spectrometry

Aim: Hepcidin-25 is the master regulator of iron homeostasis. N-truncated isoforms of hepcidin-25 have been identified (hepcidin-20, -22, -24), although data on the concentrations of these isoforms are sparse. Materials &amp; methods: Serum was mixed with aqueous formic acid, and the supernatant loaded onto a 96-well-SPE-plate. Eluted analytes were analyzed using LC–HR-MS. Forty-seven paired dipotassium-EDTA human plasma and serum samples were analyzed. Results: The LLOQ was 1 μg/l (all analytes). Accuracy and precision were acceptable. There was a good correlation (R2 &gt;0.90, all analytes) between matrices. The median (range) serum hepcidin-20, -22, -24 and -25 concentrations measured were 4 (1–40), 8 (2–20), 8 (1–50) and 39 (1–334) μg/l, respectively. Conclusion: LC–HR-MS is widely applicable to the measurement of hepcidin-25, and truncated isoforms. </jats:p

Quantum description of the orientational degrees of freedom in a biaxial nematic liquid

The quantum mechanical version of a classical model for studying the orientational degrees of freedom corresponding to a nematic liquid composed of biaxial molecules is presented. The effective degrees of freedom are described by operators carrying an SU(3) representation, which allows the explicit calculation of the partition function in the mean field approximation. The algebraic consistency conditions are solved numerically and the equilibrium phases of the system are determined. In particular, the entropy, the specific heat and the order parameters are presented for different choices of the constituent biaxial molecules. Our results reproduce the classical calculation in the limit of high temperatures and high quantum numbers.Comment: 33 pages, Latex, 11 figure