96 research outputs found

    Selection by a panel of clinicians and family representatives of important early morbidities associated with paediatric cardiac surgery suitable for routine monitoring using the nominal group technique and a robust voting process

    Get PDF
    OBJECTIVE: With survival following paediatric cardiac surgery improving, the attention of quality assurance and improvement initiatives is shifting to long-term outcomes and early surgical morbidities. We wanted to involve family representatives and a range of clinicians in selecting the morbidities to be measured in a major UK study. SETTING: Paediatric cardiac surgery services in the UK. PARTICIPANTS: We convened a panel comprising family representatives, paediatricians from referring centres, and surgeons and other clinicians from surgical centres. PRIMARY AND SECONDARY OUTCOME MEASURES: Using the nominal group technique augmented by a robust voting process to identify group preferences, suggestions for candidate morbidities were elicited, discussed, ranked and then shortlisted. The shortlist was passed to a clinical group that provided a view on the feasibility of monitoring each shortlisted morbidity in routine practice. The panel then met again to select a prioritised list of morbidities for further study, with the list finalised by the clinical group and chief investigators. RESULTS: At the first panel meeting, 66 initial suggestions were made, with this reduced to a shortlist of 24 after two rounds of discussion, consolidation and voting. At the second meeting, this shortlist was reduced to 10 candidate morbidities. Two were dropped on grounds of feasibility and replaced by another the panel considered important. The final list of nine morbidities included indicators of organ damage, acute events and feeding problems. Family representatives and clinicians from outside tertiary centres brought some issues to greater prominence than if the panel had consisted solely of tertiary clinicians or study investigators. CONCLUSION: The inclusion of patient and family perspectives in identifying metrics for use in monitoring a specialised clinical service is challenging but feasible and can broaden notions of quality and how to measure it

    Microcanonical temperature for a classical field: application to Bose-Einstein condensation

    Get PDF
    We show that the projected Gross-Pitaevskii equation (PGPE) can be mapped exactly onto Hamilton's equations of motion for classical position and momentum variables. Making use of this mapping, we adapt techniques developed in statistical mechanics to calculate the temperature and chemical potential of a classical Bose field in the microcanonical ensemble. We apply the method to simulations of the PGPE, which can be used to represent the highly occupied modes of Bose condensed gases at finite temperature. The method is rigorous, valid beyond the realms of perturbation theory, and agrees with an earlier method of temperature measurement for the same system. Using this method we show that the critical temperature for condensation in a homogeneous Bose gas on a lattice with a UV cutoff increases with the interaction strength. We discuss how to determine the temperature shift for the Bose gas in the continuum limit using this type of calculation, and obtain a result in agreement with more sophisticated Monte Carlo simulations. We also consider the behaviour of the specific heat.Comment: v1: 9 pages, 5 figures, revtex 4. v2: additional text in response to referee's comments, now 11 pages, to appear in Phys. Rev.

    Fluctuations in Nonequilibrium Statistical Mechanics: Models, Mathematical Theory, Physical Mechanisms

    Get PDF
    The fluctuations in nonequilibrium systems are under intense theoretical and experimental investigation. Topical ``fluctuation relations'' describe symmetries of the statistical properties of certain observables, in a variety of models and phenomena. They have been derived in deterministic and, later, in stochastic frameworks. Other results first obtained for stochastic processes, and later considered in deterministic dynamics, describe the temporal evolution of fluctuations. The field has grown beyond expectation: research works and different perspectives are proposed at an ever faster pace. Indeed, understanding fluctuations is important for the emerging theory of nonequilibrium phenomena, as well as for applications, such as those of nanotechnological and biophysical interest. However, the links among the different approaches and the limitations of these approaches are not fully understood. We focus on these issues, providing: a) analysis of the theoretical models; b) discussion of the rigorous mathematical results; c) identification of the physical mechanisms underlying the validity of the theoretical predictions, for a wide range of phenomena.Comment: 44 pages, 2 figures. To appear in Nonlinearity (2007

    Microneedles: A New Frontier in Nanomedicine Delivery

    Get PDF
    This review aims to concisely chart the development of two individual research fields, namely nanomedicines, with specific emphasis on nanoparticles (NP) and microparticles (MP), and microneedle (MN) technologies, which have, in the recent past, been exploited in combinatorial approaches for the efficient delivery of a variety of medicinal agents across the skin. This is an emerging and exciting area of pharmaceutical sciences research within the remit of transdermal drug delivery and as such will undoubtedly continue to grow with the emergence of new formulation and fabrication methodologies for particles and MN. Firstly, the fundamental aspects of skin architecture and structure are outlined, with particular reference to their influence on NP and MP penetration. Following on from this, a variety of different particles are described, as are the diverse range of MN modalities currently under development. The review concludes by highlighting some of the novel delivery systems which have been described in the literature exploiting these two approaches and directs the reader towards emerging uses for nanomedicines in combination with MN

    Assessing the feasibility of estimating the age and sex from virtual 3D models: A pilot study into virtual forensic anthropology

    No full text
    Virtual anthropology is an ever-growing sub-field within forensic anthropology that is being applied across a variety of forensic anthropological research areas (Franklin et al, 2016). However, no previous studies have investigated the impact of participant confidence levels in analysing 3D virtual skeletal models. This study explores the feasibility of estimating sex and age from 3D virtual skull and os coxa models, aiming to investigate the feasibility of moving the field of forensic anthropology into virtual lab spaces. A total of 71 participants completed an online survey requiring analysis of published virtual 3D skeletal models. Participants were asked to rate their confidence in the methodology and overall sex/age estimation, as well as preference for assessment method for each skeletal model. Statistical Analysis revealed that level of experience in analysing dry bones was found to not be associated with higher confidence in analysing 3D virtual remains (p=0.360 for sex of skull; p=0.494 for sex of os coxa; p=0.845 for age of os coxa). Confidence ratings for students in analysing skeletal remains in person did not predict perceived difficulty of analysing 3D virtual skeletal models (p=0.717 for sex of skull; p=0.579 for sex of os coxa; p=0.733 for age of os coxa). Prior 3D virtual experience did make a difference in confidence levels in the estimation of skull-sex and os coxa-age models (p=003 and p=0.001). Yet, prior 3D experience did not impact confidence levels with os coxa-sex (p=0.093). To provide insight into the results, the social cognitive concept of the ‘self-efficacy’ theory is discussed

    TMEM16A is implicated in the regulation of coronary flow and is altered in hypertension

    Get PDF
    Background and Purpose Coronary artery disease leads to ischaemic heart disease and ultimately myocardial infarction. Thus, it is important to determine the factors that regulate coronary blood flow. Ca2+‐activated chloride channels contribute to the regulation of arterial tone; however, their role in coronary arteries is unknown. The aim of this study was to investigate the expression and function of the main molecular correlate of Ca2+‐activated chloride channels, TMEM16A, in rat coronary arteries. Experimental Approach We performed mRNA and protein analysis, electrophysiological studies of coronary artery myocytes, and functional studies of coronary artery contractility and coronary perfusion, using novel inhibitors of TMEM16A. Furthermore, we assessed whether any changes in expression and function occurred in coronary arteries from spontaneously hypertensive rats (SHRs). Key Results TMEM16A was expressed in rat coronary arteries. The TMEM16A‐specific inhibitor, MONNA, hyperpolarised the membrane potential in U46619. MONNA, T16Ainh‐A01, and Ani9 attenuated 5‐HT/U46619‐induced contractions. MONNA and T16Ainh‐A01 also increased coronary flow in Langendorff perfused rat heart preparations. TMEM16A mRNA was increased in coronary artery smooth muscle cells from SHRs, and U46619 and 5‐HT were more potent in arteries from SHRs than in those from normal Wistar rats. MONNA diminished this increased sensitivity to U46619 and 5‐HT. Conclusions and Implications In conclusion, TMEM16A is a key regulator of coronary blood flow and is implicated in the altered contractility of coronary arteries from SHRs

    4-Aminopyridine: a pan voltage-gated potassium channel inhibitor that enhances K7.4 currents and inhibits noradrenaline-mediated contraction of rat mesenteric small arteries

    No full text
    BACKGROUND AND PURPOSE: Kv 7.4 and Kv 7.5 channels are regulators of vascular tone. 4-Aminopyridine (4-AP) is considered a broad inhibitor of voltage-gated potassium (KV ) channels, with little inhibitory effect on Kv 7 family members at mmol concentrations. However, the effect of 4-AP on Kv 7 channels has not been systematically studied. The aim of this study was to investigate the pharmacological activity of 4-AP on Kv 7.4 and Kv 7.5 channels and characterize the effect of 4-AP on rat resistance arteries. EXPERIMENTAL APPROACH: Voltage clamp experiments were performed on Xenopus laevis oocytes injected with cRNA encoding KCNQ4 or KCNQ5, HEK cells expressing Kv 7.4 channels and on rat, freshly isolated mesenteric artery smooth muscle cells. The effect of 4-AP on tension, membrane potential, intracellular calcium and pH was assessed in rat mesenteric artery segments. KEY RESULTS: 4-AP increased the Kv 7.4-mediated current in oocytes and HEK cells but did not affect Kv 7.5 current. 4-AP also enhanced native mesenteric artery myocyte K+ current at sub-mmol concentrations. When applied to NA-preconstricted mesenteric artery segments, 4-AP hyperpolarized the membrane, decreased [Ca2+ ]i and caused concentration-dependent relaxations that were independent of 4-AP-mediated changes in intracellular pH. Application of the Kv 7 channel blocker XE991 and BKCa channel blocker iberiotoxin attenuated 4-AP-mediated relaxation. 4-AP also inhibited the NA-mediated signal transduction to elicit a relaxation. CONCLUSIONS AND IMPLICATIONS: These data show that 4-AP is able to relax NA-preconstricted rat mesenteric arteries by enhancing the activity of Kv 7.4 and BKCa channels and attenuating NA-mediated signalling
    corecore