Homomorphically Full Oriented Graphs

Homomorphically full graphs are those for which every homomorphic image is isomorphic to a subgraph. We extend the definition of homomorphically full to oriented graphs in two different ways. For the first of these, we show that homomorphically full oriented graphs arise as quasi-transitive orientations of homomorphically full graphs. This in turn yields an efficient recognition and construction algorithms for these homomorphically full oriented graphs. For the second one, we show that the related recognition problem is GI-hard, and that the problem of deciding if a graph admits a homomorphically full orientation is NP-complete. In doing so we show the problem of deciding if two given oriented cliques are isomorphic is GI-complete

Application of laser anemometry in acoustic measurement standards

The absolute measurement of acoustic particle velocity using Laser Doppler Anemometry (LDA) provides the basis for a method of microphone calibration. In this thesis, after the current standardized calibration method (called reciprocity) is explained, the application of LDA to the determination of sound pressure acting on a microphone is discussed. From a measurement of the output voltage for a given sound pressure, the sensitivity of the microphone can be calculated. In LDA, there are two different techniques for detecting and analysing the Doppler signal generated by acoustic particle motion: continuous detection followed by frequency or time domain analysis, and photon correlation. After a brief discussion of the theory of both methods, their application to measurements within a standing-wave tube is investigated. Velocity measurements extracted from Doppler signals are used to derive values of sound pressure, which are compared with probe microphone measurements. The continuous detection and photon correlation LDA systems are used to measure particle velocity amplitude in a standing wave for frequencies between 660 Hz and 4kHz and velocities between 1 mms⁻¹ and 18 mms⁻¹. LDA is applied to the measurement of microphone sensitivity. The frequency response of the probe microphone is characterized relative to the response of a reference microphone. From the frequency response information, the output voltage of the probe microphone, and the LDA derived sound pressure in a standing wave the sensitivity of the reference microphone is established. Using the continuous detection system, the microphone sensitivity is measured to within ±0.1 dB of the sensitivity obtained by reciprocity calibration for frequencies between 660 Hz and 2 kHz. Using the photon correlation system, the sensitivity is measured to within ±0.2 dB for the same frequency range. Initial measurements were performed in a free field environment, using the photon correlation system, to demonstrate the potential for further development of the LDA calibration technique

An evaluation of the use and handling errors of currently available recombinant human follicle-stimulating hormone pen injectors by women with infertility and fertility nurses

Background: This study compared preference ratings of women with infertility and nurses before and after simulated injection, and handling errors, with the GONAL-f®, Bemfola®, Ovaleap® and Rekovelle® pen injectors. Research design and methods: Injector-naïve women and injector-experienced fertility nurses tested injectors with masked labels in a randomized testing order. Injections were made into a foam pad and injectors were rated before and after use. Handling errors were recorded during the study. Ratings and errors were compared between pen injectors using ordinal or Poisson linear mixed models adjusted for testing order. Results: 120 women and 60 nurses participated. All participants tested GONAL-f and Bemfola injectors. Because of their similarity, participants tested either Rekovelle (71 women; 30 nurses) or Ovaleap (49 women; 30 nurses) injectors. The ratings from women were higher for GONAL-f vs other injectors after simulated use (p < 0.001 for all comparisons). Fertility nurses rated GONAL-f injector higher than other injectors both before and after use (p < 0.01 for all comparisons). Adjusted rates of total handling errors were lower with the GONAL-f vs other injectors (p < 0.001 for all comparisons) for both groups. Conclusions: GONAL-f injector was rated significantly higher than other injectors, which may be related to less handling errors observed with the GONAL-f injector. ispartof: EXPERT OPINION ON DRUG DELIVERY vol:16 issue:9 pages:1003-1014 ispartof: location:England status: publishe

Multi-modal retinal scanning to measure retinal thickness and peripheral blood vessels in multiple sclerosis

Our purpose was to investigate changes to the retina in multiple sclerosis (MS) using established and novel modes of retinal image acquisition and analysis. 72 participants with MS and 80 healthy volunteers underwent retinal scanning with optical coherence tomography (OCT) and ultra-widefield (UWF) scanning laser ophthalmoscopy (SLO), over a two-year period. Changes in retinal nerve fibre layer (RNFL) thickness, macular volume and retinal blood vessel diameter were measured and parameters were then tested for associations with MS. Measurements from OCT showed that individuals with MS had a thinner RNFL and reduced macular volume when compared to healthy volunteers. On UWF images, participants with MS had reduced arterial widths in the inferior nasal quadrant of both eyes and reduced venous widths in the inferior nasal quadrant of right eyes. Longitudinal analysis showed that participants with MS had an accelerated annual rate of RNFL thinning in several regions of the retina. In conclusion, the assessment of OCT showed thinning of the RNFL and macula in concordance with previous reports on MS, while analysis of blood vessels in the retinal periphery from UWF-SLO images revealed novel changes

Transcatheter Versus Surgical Aortic Valve Replacement in Young, Low-risk Patients with Severe Aortic Stenosis

Aortic stenosis is a common form of acquired degenerative valvular disease associated with poor survival after the onset of symptoms. Treatment options for patients with aortic stenosis in addition to medical therapy include surgical aortic valve replacement (SAVR) with either tissue or mechanical valves, or transcatheter aortic valve replacement (TAVR) with either balloon-expandable or self-expanding valves via either transfemoral or alternative access routes. In this review, the authors discuss the current evidence and special considerations regarding the use of TAVR versus SAVR in the management of severe aortic stenosis in young (<65 years of age), low-risk patients, highlighting the history of aortic stenosis treatment, the current guidelines and recommendations, and important issues that remain to be addressed. Ultimately, until ongoing clinical trials with long-term follow-up data shed light on whether interventions for aortic stenosis can be broadened to a low-risk population, TAVR in young, low-risk patients should be undertaken with caution and with guidance from a multidisciplinary heart team

The application of retinal fundus camera imaging in dementia:A systematic review

INTRODUCTION: The ease of imaging the retinal vasculature, and the evolving evidence suggesting this microvascular bed might reflect the cerebral microvasculature, presents an opportunity to investigate cerebrovascular disease and the contribution of microvascular disease to dementia with fundus camera imaging. METHODS: A systematic review and meta-analysis was carried out to assess the measurement of retinal properties in dementia using fundus imaging. RESULTS: Ten studies assessing retinal properties in dementia were included. Quantitative measurement revealed significant yet inconsistent pathologic changes in vessel caliber, tortuosity, and fractal dimension. Retinopathy was more prevalent in dementia. No association of age-related macular degeneration with dementia was reported. DISCUSSION: Inconsistent findings across studies provide tentative support for the application of fundus camera imaging as a means of identifying changes associated with dementia. The potential of fundus image analysis in differentiating between dementia subtypes should be investigated using larger well-characterized samples. Future work should focus on refining and standardizing methods and measurements

Concordance between SIVA, IVAN, and VAMPIRE software tools for semi-automated analysis of retinal vessel caliber

We aimed to compare measurements from three of the most widely used software packages in the literature and to generate conversion algorithms for measurement of the central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE) between SIVA and IVAN and between SIVA and VAMPIRE. We analyzed 223 retinal photographs from 133 human participants using both SIVA, VAMPIRE and IVAN independently for computing CRAE and CRVE. Agreement between measurements was assessed using Bland–Altman plots and intra-class correlation coefficients. A conversion algorithm between measurements was carried out using linear regression, and validated using bootstrapping and root-mean-square error. The agreement between VAMPIRE and IVAN was poor to moderate: The mean difference was 20.2 µm (95% limits of agreement, LOA, −12.2–52.6 µm) for CRAE and 21.0 µm (95% LOA, −17.5–59.5 µm) for CRVE. The agreement between VAMPIRE and SIVA was also poor to moderate: the mean difference was 36.6 µm (95% LOA, −12.8–60.4 µm) for CRAE, and 40.3 µm (95% LOA, 5.6–75.0 µm) for CRVE. The agreement between IVAN and SIVA was good to excellent: the mean difference was 16.4 µm (95% LOA, −4.25–37.0 µm) for CRAE, and 19.3 µm (95% LOA, 0.09–38.6 µm) for CRVE. We propose an algorithm converting IVAN and VAMPIRE measurements into SIVA-estimated measurements, which could be used to homogenize sets of vessel measurements obtained with different software packages