158 research outputs found

    Homogeneous bubble nucleation limit of mercury under the normal working conditions of the planned European Spallation Source

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    In spallation neutron sources, liquid mercury is the subject of big thermal and pressure shocks, upon adsorbing the proton beam. These changes can cause unstable bubbles in the liquid, which can damage the structural material. While there are methods to deal with the pressure shock, the local temperature shock cannot be avoided. In our paper we calculated the work of the critical cluster formation (i.e. for mercury micro-bubbles) together with the rate of their formation (nucleation rate). It is shown that the homogeneous nucleation rates are very low even after adsorbing several proton pulses, therefore the probability of temperature induced homogeneous bubble nucleation is negligible.Comment: 22 Pages, 11 figures, one of them is colour, we plan to publish it in Eur. Phys. J.

    Incidence of end-stage renal disease after heart transplantation and effect of its treatment on survival

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    Aims: Many heart transplant recipients will develop end-stage renal disease in the post-operative course. The aim of this study was to identify the long-term incidence of end-stage renal disease, determine its risk factors, and investigate what subsequent therapy was associated with the best survival. Methods and results: A retrospective, single-centre study was performed in all adult heart transplant patients from 1984 to 2016. Risk factors for end-stage renal disease were analysed by means of multivariable regression analysis and survival by means of Kaplan–Meier. Of 685 heart transplant recipients, 71 were excluded: 64 were under 18 years of age and seven were re-transplantations. During a median follow-up of 8.6 years, 121 (19.7%) patients developed end-stage renal disease: 22 received conservative therapy, 80 were treated with dialysis (46 haemodialysis and 34 peritoneal dialysis), and 19 received a kidney transplant. Development of end-stage renal disease (examined as a time-dependent variable) inferred a hazard ratio of 6.45 (95% confidence interval 4.87–8.54, P < 0.001) for mortality. Tacrolimus-based therapy decreased, and acute kidney injury requiring renal replacement therapy increased the risk for end-stage renal disease development (hazard ratio 0.40, 95% confidence interval 0.26–0.62, P < 0.001, and hazard ratio 4.18, 95% confidence interval 2.30–7.59, P < 0.001, respectively). Kidney transplantation was associated with the best median survival compared with dialysis or conservative therapy: 6.4 vs. 2.2 vs. 0.3 years (P < 0.0001), respectively, after end-stage renal disease development. Conclusions: End-stage renal disease is a frequent complication after heart transplant and is associated with poor survival. Kidney transplantation resulted in the longest survival of patients with end-stage renal disease

    Impact of Continuous Flow Left Ventricular Assist Device Therapy on Chronic Kidney Disease: A Longitudinal Multicenter Study

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    Background: Many patients undergoing durable left ventricular assist device (LVAD) implantation suffer from chronic kidney disease (CKD). Therefore, we investigated the effect of LVAD support on CKD. Methods: A retrospective multicenter cohort study, including all patients undergoing LVAD (HeartMate II (n = 330), HeartMate 3 (n = 22) and HeartWare (n = 48) implantation. In total, 227 (56.8%) patients were implanted as bridge-to-transplantation; 154 (38.5%) as destination therapy; and 19 (4.7%) as bridge-to-decision. Serum creatinine measurements were collected over a 2-year follow-up period. Patients were stratified based on CKD stage. Results: Overall, 400 patients (mean age 53 ± 14 years, 75% male) were included: 186 (46.5%) patients had CKD stage 1 or 2; 93 (23.3%) had CKD stage 3a; 82 (20.5%) had CKD stage 3b; and 39 (9.8%) had CKD stage 4 or 5 prior to LVAD implantation. During a median follow-up of 179 days (IQR 28–627), 32,629 creatinine measurements were available. Improvement of kidney function was noticed in every preoperative CKD-stage group. Following this improvement, estimated glomerular filtration rates regressed to baseline values for all CKD stages. Patients showing early renal function improvement were younger and in worse preoperative condition. Moreover, survival rates were higher in patients showing early improvement (69% vs 56%, log-rank P = 0.013). Conclusions: Renal function following LVAD implantation is characterized by improvement, steady state and subsequent deterioration. Patients who showed early renal function improvement were in worse preoperative condition, however, and had higher survival rates at 2 years of follow-up

    Preoperative right heart hemodynamics predict postoperative acute kidney injury after heart transplantation

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    Purpose: Acute kidney injury (AKI) frequently occurs after heart transplantation (HTx), but its relation to preoperative right heart hemodynamic (RHH) parameters remains unknown. Therefore, we aimed to determine their predictive properties for postoperative AKI severity within 30 days after HTx. Methods: From 1984 to 2016, all consecutive HTx recipients (n = 595) in our tertiary referral center were included and analyzed for the occurrence of postoperative AKI staged by the kidney disease improving global outcome criteria. The effects of preoperative RHH parameters on postoperative AKI were calculated using logistic regression, and predictive accuracy was assessed using integrated discrimination improvement (IDI), net reclassification improvement (NRI), and area under the receiver operating characteristic curves (AUC). Results: Postoperative AKI occurred in 430 (72%) patients including 278 (47%) stage 1, 66 (11%) stage 2, and 86 (14%) stage 3 cases. Renal replacement therapy (RRT) was administered in 41 (7%) patients. Patients with higher AKI stages had also higher baseline right atrial pressure (RAP; median 7, 7, 8, and in RRT 11 mmHg, p trend = 0.021), RAP-to-pulmonary capillary wedge pressure ratio (median 0.37, 0.36, 0.40, 0.47, p trend = 0.009), and lower pulmonary artery pulsatility index (PAPi) values (median 2.83, 3.17, 2.54, 2.31, p trend = 0.012). Higher RAP and lower PAPi values independently predicted AKI severity [adjusted odds ratio (OR) per doubling of RAP 1.16 (1.02–1.32), p = 0.029; of PAPi 0.85 (0.75–0.96), p = 0.008]. Based on IDI, NRI, and delta AUC, inclusion of these parameters improved the models’ predictive accuracy. Conclusions: Preoperative PAPi and RAP strongly predict the development of AKI early after HTx and can be used as early AKI predictors

    MMN and Differential Waveform

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    A mismatch negativity response (MMN) and a new differential waveform were derived in an effort to evaluate a neural refractory or recovery effect in adult listeners. The MMN was elicited using oddball test runs in which the standard and deviant stimuli differed in frequency. To derive the differential waveform, the same standard and deviant stimuli were presented alone. MMN responses were obtained by subtracting the averaged responses to standards from the deviants. The differential waveforms were obtained by subtracting the averaged responses to standards presented alone from deviants presented alone. Scalp topography for the MMN and differential waveforms were similar. A significant (p < .05) positive and negative correlation was found between the earlier and later components of the bimodal MMN and the N1 and P2 component of the differential waveform, respectively. Further, N1 and P2 of the differential waveform were significant (p < .05) predictor variables of early and late peak amplitudes of the MMN. These results suggest that refractory effects may overlay/modify the morphology of the MMN waveform

    Addressing perinatal health inequities in Dutch municipalities: Protocol for the Healthy Pregnancy 4 All-3 programme

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    Background: Health inequities are already present at birth and affect individuals’ health and socioeconomic outcomes across the life course. Addressing these inequities requires a cross-sectoral approach, covering the first 1,000 days of life. We believe that - in the Dutch context - municipal governments can be the main responsible actor to drive such an approach, since they are primarily responsible for organising adequate public health. Therefore, we aim to identify and develop transformative change towards the implementation of perinatal health into municipal approaches and policies concerning health inequities. Methods: A transition analysis will be combined with action research in six Dutch municipalities. Interviews and interactive group sessions with professionals and organisations that are relevant for the institutional embedding of perinatal health into approaches and policies regarding health inequities, will be organised in each municipality. As a follow-up, a questionnaire will be administered among all participants one year after completion of the group sessions. Discussion: We expect to gain insights into the role of municipalities in addressing perinatal health inequities, learn more about the interaction between different key stakeholders, and identify barriers and facilitators for a cross-sectoral approach to perinatal health. This knowledge will serve to inform the development of approaches to perinatal health inequities in areas with relatively poor perinatal health outcomes, both in the Netherlands and abroad

    Women’s beliefs about medicines and adherence to pharmacotherapy in pregnancy: Opportunities for community pharmacists?

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    Background During pregnancy women might weigh benefits of treatment against potential risks to the unborn child. However, non-adherence to necessary treatment can adversely affect both mother and child. To optimize pregnant women’s beliefs and medication adherence, community pharmacists are ideally positioned to play an important role in primary care. Objective This narrative review aimed to summarize the evidence on 1) pregnant women’s beliefs, 2) medication adherence in pregnancy, and 3) community pharmacists’ counselling during pregnancy. Method Three search strategies were used in Medline and Embase to find original studies evaluating women’s beliefs, medication adherence and community pharmacists’ counselling during pregnancy. All original descriptive and analytic epidemiological studies performed in Europe, North America and Australia, written in English and published from 2000 onwards were included. Results We included 14 studies reporting on women’s beliefs, 11 studies on medication adherence and 9 on community pharmacists’ counselling during pregnancy. Women are more reluctant to use medicines during pregnancy and tend to overestimate the teratogenic risk of medicines. Risk perception varies with type of medicine, level of health literacy, education level and occupation. Furthermore, low medication adherence during pregnancy is common. Finally, limited evidence showed current community pharmacists’ counselling is insufficient. Barriers hindering pharmacists are insufficient knowledge and limited access to reliable information. Conclusion Concerns about medication use and non-adherence are widespread among pregnant women. Community pharmacists’ counselling during pregnancy is insufficient. Further education, training and research are required to support community pharmacists in fulfilling all the opportunities they have when counselling pregnant women
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