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BACKGROUND AND AIMS Although the risk for congestive heart failure (CHF) decreases after kidney transplantation (KT) compared with dialysis, it remains a significant clinical concern associated with a higher risk of mortality, cardiovascular events and kidney graft loss. Available epidemiological data on CHF after KT are limited, outdated and have mostly focused on traditional risk factors. We aim to describe the risk, predictors and outcomes associated with de novo CHF after KT. METHOD We used electronic patient records from the West of Scotland renal database to retrospectively investigate de novo CHF in adult kidney transplant recipients between 1 January 2010 and 31 March 2020. Heart failure was ascertained using a combination of physician-reported diagnosis, echocardiographic criteria, radiological evidence of heart failure and elevation of NT-proBNP levels. Participants were followed up until 15 April 2021. Multivariable regression analysis was used to identify independent correlates of post-transplantation de novo CHF (odds ratio [OR] and 95% confidence interval [CI]) and examine de novo CHF as a predictor of death and graft loss after transplantation. RESULTS One hundred and four (8.9%) of 1172 transplant recipients had de novo CHF [mean age, 50 ± 13 years; 470 (40%) women]. The cumulative incidences of de novo CHF were 3.8% (95% CI: 2.9–5.1), 5.2% (95% CI: 4.1–6.7) and 7.1% (95% CI: 5.6–8.9) at 1, 3 and 5 years, respectively. Risk factors for de novo CHF included older recipient age (OR: 1.04; 95% CI: 1.02–1.06; P CONCLUSION Congestive heart failure is a common complication after kidney transplantation associated with markedly increased risk for death and graft loss. Identification and optimization of pretransplantation risk factors for CHF and pre-emptive transplantation, suggests targets for improving outcomes.

The sensors abnormalities, faults, failure detection and diagnosis for marine engines are considered crucial for ensuring the engine safe and smooth operation. The development of such system(s) is typically based on the manufacturers experience on sensors and actuators faults and failure events. This study aims to introduce a novel methodology for the sensors diagnostics and health management in marine dual fuel engines by employing a combination of thermodynamic, functional control and data-driven models. The concept of an Engine Diagnostics System (EDS) is developed to provide intelligent engine monitoring, advanced sensors’ faults detection as well as timely and profound corrective actions. This system employs a neural networks (NN) Data-Driven (DD) model along with appropriate logic controls. The DD model is set up based on the derived steady state data from a thermodynamic model of high fidelity and is capable of real-time prediction of the engine health condition behaviour. The concept of a novel Unified Digital System (UDS) is proposed that combines the engine’s existing control and diagnostic systems with the EDS. The functionality of the UDS system is validated by employing a digital twin of the considered marine dual fuel engine by investigating scenarios for assessing the engine performance that entail abnormalities in the engine’s speed and boost pressure sensors. The simulation results demonstrate that the developed UDS is capable of sufficiently capturing the engine’s sensors abnormalities and applying appropriate corrective actions to restore the engine operation in its original state. This study benefits the development future systems facilitating the engines condition assessment and self-correction of the engine sensors’ abnormalities, which will be required for smart and autonomous shipping.

Recent developments have rendered the Dual Fuel (DF) engines an attractive alternative solution for achieving cost-efficient compliance to environmental regulations. The present study focuses on the safety investigation of a marine DF engine in order to identify potential safety implications. This investigation is based on an integrated engine model, which was developed in GT-ISE™ software and is capable of predicting both the engine steady-state behaviour and transient response. The model includes the engine thermodynamic simulation module as well as the engine control system functional module; the latter is responsible for implementing the ordered load changes and the operating mode switching. The developed model is first validated against available published data and subsequently used to simulate several test cases with fuel changes, from gas to diesel and diesel to gas with rapid and with delayed wastegate valve operation. The derived simulation results are used to investigate the potential safety implications that can arise during the engine operation. The results demonstrate that the engine–turbocharger matching as well as the wastegate control are critical parameters for ensuring the compressor surge free operation during gas to diesel modes transition. Abbreviations: 0D: zero-dimensional; 1D: one-dimensional; BMEP: brake mean effective pressure; CO 2: carbon dioxide; DF: dual fuel; D/G: diesel generator; DTG: diesel to gas fuel modes switching; ECA: emission control area; ECS: engine control system; EEDI: energy efficiency design index; GTD: gas to diesel modes switching; HFO: heavy fuel oil; IMO: International Maritime Organization; LFO: light fuel oil; LNG: liquefied natural gas; MCR: maximum continuous rating; NOx: nitrogen oxides; PHA: preliminary hazard analysis; PI: proportional–integral; SOx: sulphur oxides; TC: turbocharger; WG: wastegate; λ: air–fuel equivalence ratio.

Arteriovenous fistula (AVF) is the preferred type of vascular access for maintenance haemodialysis but it may contribute to maladaptive cardiovascular remodelling. We studied the effect of AVF creation on cardiac structure and function in patients with chronic kidney disease (CKD). In this prospective cohort study patients with CKD listed for first AVF creation underwent cardiac magnetic resonance (CMR) imaging at baseline and at 6 weeks. All participants had ultrasound measurements of fistula blood flow at 6 weeks. The primary outcome was the change in left ventricular (LV) mass. Secondary outcomes included changes in LV volumes, LV ejection fraction, cardiac output, LV global longitudinal strain and N-terminal-pro B-type natriuretic peptide (NT-proBNP). A total of 55 participants were enrolled, of whom 40 (mean age 59 years) had AVF creation and completed both scans. On the second CMR scan, a mean increase of 7.4 g (95% CI 1.1–13.7, p = 0.02) was observed in LV mass. Significant increases in LV end-diastolic volumes (p = 0.04) and cardiac output (p = 0.02) were also seen after AVF creation. No significant changes were observed in LV end-systolic volumes, LV ejection fraction, NT-proBNP and LV global longitudinal strain. In participants with fistula blood flows ≥ 600 mL/min (n = 22) the mean increase in LV mass was 15.5 g (95% CI 7.3–23.8) compared with a small decrease of 2.5 g (95% CI − 10.6 to 5.6) in participants with blood flows

Marine Dual Fuel engines have been proved an attractive solution to improve the shipping industry sustainability and environmental footprint. Compared to the conventional diesel engines, the use of additional components to accommodate the natural gas feeding is associated with several safety implications. To ensure the engine safe operation, appropriate engine control and safety systems are of vital importance, whilst potential safety implications due to sensors and actuators faults or failures must be considered. This study aims at investigating the safety issues of a marine dual fuel (DF) engine considering critical operating scenarios, which are identified by employing a Failure Mode, Effects and Criticality Analysis. An existing verified digital twin (DT) of the investigated DF engine, capable of predicting the engine response at steady state and transient conditions with sufficient accuracy is employed to simulate the engine operation for the identified scenarios. The simulated scenarios results analysis is used to support the risk priority number assessment and identify the potential safety implications by considering the manufacturer alarm limits. Appropriate measures are recommended for the investigated DF engine safety performance improvement. This study demonstrates a methodology integrating existing safety methods with state-of-the-art simulation tools for facilitating and enhancing the safety assessment process of marine DF engines considering both steady state conditions and transient operation with main focus on switching operating modes.

Despite arteriovenous fistulae (AVF) being the preferred vascular access for haemodialysis, high primary failure rates (30-70%) and low one-year patency rates (40-70%) hamper their use. The haemodynamics within the vessels of the fistula change significantly following surgical creation of the anastomosis and can be a surrogate of AVF success or failure. Computational fluid dynamics (CFD) can crucially predict AVF outcomes through robust analysis of a fistula’s haemodynamic patterns, which is impractical in-vivo. We present a proof-of-concept CFD framework for characterising the AVF blood flow prior and following surgical creation of a successful left radiocephalic AVF in a 20-year-old end-stage kidney disease patient. The reconstructed vasculature was generated utilising multiple contrast-enhanced magnetic resonance imaging (MRI) datasets. Large eddy simulations were conducted for establishing the extent of arterial and venous remodelling. Following anastomosis creation, a significant 2-3-fold increase in blood flow rate was induced downstream of the left subclavian artery. This was validated through comparison with post-AVF patient-specific phase-contrast data. The increased flow rate yielded an increase in time-averaged wall shear stress (TAWSS), a key marker of adaptive vascular remodelling. We have demonstrated TAWSS and oscillatory shear distributions of the transitional-flow in the venous anastomosis are predictive of AVF remodelling.

Objective: \ud The predicted outcomes of autogenous arteriovenous (AV) hemodialysis access creation are predominantly based on historical data; however, both the hemodialysis population and clinical practices have changed significantly during the last decade. This study examined contemporary AV access clinical use and patencies.\ud \ud Methods: \ud A multicenter observational cohort study was performed of all new AV accesses created in Scotland in 2015. The primary end point was efficacy assessed by successful AV access use for a minimum of 30 days and primary, primary assisted, and secondary patency at 1 year. Data obtained included all interventions to maintain or to restore patency. Predictors of patency loss including demographics, comorbid conditions, dialysis status, AV access location, duplex ultrasound surveillance, procedures, prior access, and antiplatelets were assessed. Kaplan-Meier and competing risks analyses were performed to estimate the probability of AV access failure. All patients were followed up for at least 1 year or had a censoring event.\ud \ud Results: \ud A total of 582 AV accesses were created in 537 patients (mean age, 60 [standard deviation, 14] years; 60% men; 42% with diabetes) in nine adult renal centers. Mean follow-up was 11.8 (standard deviation, 7.6) months. By the end of the follow-up, 322 (55.3%) AV accesses were successfully used for dialysis. At 1 year, 48% (95% confidence interval [CI], 44-52) of AV accesses had primary patency, (95% CI, 63-71) had primary assisted patency, and 69% (95% CI, 65-73) had secondary patency. The leading cause of primary patency loss was primary failure (30%). An average of 0.48 intervention per patient-year was required to maintain patency. On multivariable analysis, patency was better for an upper arm than for a forearm AV access (1-year secondary patency of upper arm vs forearm AV accesses, 74% vs 58%). The cumulative hazard and incident functions for AV access failure were 31% (95% CI, 27-35) and 23% (95% CI, 20-27) at 1 year, respectively.\ud \ud Conclusions: \ud Despite advances in recent years with preoperative vessel assessment and surveillance, patency rates have not improved, with primary failure remaining the major obstacle. Competing events should be taken into consideration; otherwise, biases may occur with overestimation of the probability of AV access failure.

Objectives Ferumoxytol is an alternative to gadolinium-based compounds as a vascular contrast agent for magnetic resonance angiography (MRA), particularly for patients with chronic kidney disease (CKD). However, dose-related efficacy data are lacking. We aimed to determine the optimal (minimum effective) dose of ferumoxytol for MRA in patients with CKD. Methods Ferumoxytol-enhanced MRA (FeMRA) was performed at 3.0 T in patients with CKD after dose increments up to a total of 4 mg/kg. Image quality was assessed by contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) in the abdominal aorta and inferior vena cava. Quadratic regression analyses were performed to estimate the effects of dose increments on CNR and SNR. Results Twenty-three patients underwent FeMRA (mean age 60 [SD 13] years, 87% men, 48% had diabetic nephropathy) with cumulative doses of 0, 1, 2, 3 and 4 mg/kg of ferumoxytol. On regression analyses, a parabolic relationship was observed between ferumoxytol dose and signal with progressive signal loss using doses exceeding 4 mg/kg. A dose of 3 mg/kg achieved ≥ 75% of predicted peak CNR and SNR and images were deemed of excellent diagnostic quality. Conclusions In patients with CKD undergoing FeMRA, a dose of 3 mg/kg provides excellent arterial and venous enhancement. The benefits of increasing the dose to a theoretically optimal value of 4 mg/kg appear to be negligible and likely of minimal, if any, diagnostic value. Key Points • Ferumoxytol is used off-label as an MRI contrast agent but dose-related data are lacking. • In patients with CKD requiring MR angiography, a dose of 3 mg/kg provides excellent vascular enhancement. Electronic supplementary material The online version of this article (10.1007/s00330-019-06137-4) contains supplementary material, which is available to authorized users.

Despite arteriovenous fistulae (AVF) being the preferred vascular access for haemodialysis, high primary failure rates (30-70%) and low one-year patency rates (40-70%) hamper their use. Furthermore, AVF creation has been associated with haemodynamic changes causing maladaptive cardiac remodelling leading to cardiovascular (CV) complications. In this study, we present a new workflow for characterising the haemodynamic profile prior to and following surgical creation of a successful left radiocephalic AVF in a 20-year-old end-stage kidney disease patient. The reconstructed vasculature was generated using multiple ferumoxytol-enhanced magnetic resonance angiography (FeMRA) datasets. Computational fluid dynamics (CFD) simulations utilising a scale-resolving turbulence model were completed to investigate the changes in the proximal haemodynamics following AVF creation, in addition to the post-AVF juxta-anastomosis flow patterns, which is impractical to obtain in-vivo. Following AVF creation, a significant 2-3-fold increase in blood flow rate was induced downstream of the left subclavian artery. This was validated through comparison with post-AVF patient-specific phase-contrast data. Proximal to the anastomosis, the increased flow rate yielded an increase in time-averaged wall shear stress (WSS), which is a key marker of adaptive vascular remodelling. In the juxta-anastomosis region, the success of the AVF was discussed with respect to the National Kidney Foundation's vascular access guidelines, where the patient-specific AVF met the flow rate and geometry criterion. The AVF venous diameter exceeded 6mm and the venous flow rate surpassed 600mL/min. This workflow may potentially be significant clinically when applied to multi-patient cohorts, with population-wide patient-specific conclusions being ascertained for the haemodynamic assessment of AVFs and improved surgical planning.

Background Vascular calcification is an independent predictor of cardiovascular disease in patients with chronic kidney disease. Computed tomography (CT) is the gold-standard for detecting vascular calcification. Radial volumetric-interpolated breath-hold examination (radial-VIBE), a free-breathing gradient-echo cardiovascular magnetic resonance (CMR) sequence, has advantages over CT as it is ionising radiation-free. However, its capability in detecting thoracic aortic calcification (TAC) has not been investigated. This study aims to compare radial-VIBE to CT for the detection of TAC in the descending aorta of patients with end-stage renal disease (ESRD) using semi-automated methods, and to investigate the association between TAC and coronary artery calcification (CAC). Methods Paired cardiac CT and radial-VIBE CMR scans from ESRD patients participating in 2 prospective studies were obtained. Calcification volume was quantified using semi-automated methods in a 9 cm segment of the thoracic aorta. Correlation and agreement between TAC volume measured on CMR and CT were assessed with Spearman’s correlation coefficient (ρ), linear regression, Bland–Altman plots and intraclass correlation coefficient (ICC). Association between CAC Agatston score and TAC volume determined by CT and CMR was measured with Spearman’s correlation coefficient. Results Scans from 96 participants were analysed. Positive correlation was found between CMR and CT calcification volume [ρ = 0.61, 95% confidence interval (CI) 0.45–0.73]. ICC for consistency was 0.537 (95% CI 0.378–0.665). Bland–Altman plot revealed that compared to CT, CMR volumes were systematically higher at low calcification volume, and lower at high calcification volume. CT did not detect calcification in 41.7% of participants, while radial-VIBE CMR detected signal which the semi-quantitative algorithm reported as calcification in all of those individuals. Instances of suboptimal radial-VIBE CMR image quality were deemed to be the major contributors to the discrepancy. Correlations between CAC Agatston score and TAC volume measured by CT and CMR were ρ = 0.404 (95% CI 0.214–0.565) and ρ = 0.211 (95% CI 0.008–0.396), respectively. Conclusion Radial-VIBE CMR can detect TAC with strong positive association to CT, albeit with the presence of proportional bias. Quantification of vascular calcification by radial-VIBE remains a promising area for future research, but improvements in image quality are necessary.

Background Duplex US is performed routinely for vascular mapping prior to arteriovenous fistula (AVF) creation for hemodialysis but cannot demonstrate the central vasculature. Ferumoxytol, an iron oxide nanoparticle, provides an alternative to gadolinium contrast material for MR angiography for safe use in chronic kidney disease (CKD). Purpose To assess the clinical utility of ferumoxytol-enhanced MR angiography compared with duplex US for vascular mapping before upper limb AVF creation in participants with CKD. Materials and Methods In a prospective comparative study (ClinicalTrials.gov: NCT02997046) from December 2016 to August 2018, participants with CKD underwent ferumoxytol-enhanced MR angiography and duplex US. Two independent readers evaluated vessels for diameter, stenosis or occlusion, arterial disease, and central stenosis. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to assess intra- and interreader variability. On the basis of accepted standards for AVF creation, an algorithm was developed to predict AVF outcome based on imaging findings. Multivariable regression models used AVF success as the dependent variable and age, sex, and duplex US or ferumoxytol-enhanced MR angiography findings as independent variables. Results Fifty-nine participants with CKD (mean age, 59 years ± 13 [standard deviation]; 30 women) were evaluated. A total of 51 fistulas were created, of which 24 (47%) were successful. Ferumoxytol-enhanced MR angiography showed excellent inter- and intrareader repeatability (ICC, 0.84-0.99) for all variables assessed. In addition to revealing 15 central vasculature stenoses, ferumoxytol-enhanced MR angiography resulted in characterization of 88 of 236 (37%) of the arterial sections examined as unsuitable for AVF creation compared with 61 of 236 (26%) sections with duplex US (

Background and Aims Arteriovenous fistula (AVF) is considered the preferred type of access for maintenance haemodialysis. The creation of an AVF may contribute to maladaptive cardiovascular remodelling. We conducted a study to evaluate the effect of AVF creation on cardiac structure and function in patients with end-stage renal disease (ESRD). Method In this prospective cohort study, patients with ESRD listed for AVF creation underwent cardiac magnetic resonance imaging at baseline and at 6 weeks. All participants had ultrasound measurements of AVF blood flow at 6 weeks. The primary outcome was the change in left ventricular (LV) mass. Secondary outcomes included changes in LV volumes, left atrial volume, LV ejection fraction, LV global longitudinal strain, cardiac output/index, and septal thickness. Results A total of 65 patients were enrolled, of whom 40 had an AVF creation and completed both scans. Patients were divided into 2 groups based on AVF blood flows: 22 in the high flow group (≥ 600mL/min) and 18 in the low flow group (< 600mL/min). On the second cardiac magnetic resonance scan, a mean increase of 7.4 g (95% CI, 1.1–13.7, P=0.02) was observed in LV mass; in the high flow group the mean increase was 15.5 g (95% CI, 7.3–23.8) compared with a small decrease of 2.5 g (95% CI, −10.6 to 5.6) in the low flow group (P=0.003). Significant increases in LV end-diastolic volumes, cardiac output, and cardiac index were also seen after AVF creation (P Conclusion Creation of AVF in adults with ESRD resulted in significant increase of LV myocardial mass early after surgery.

The continuous stringent requirements of the environmental regulations along with the LNG fuel penetration and the development of port and bunkering facilities, render the use of the dual fuel engines an attractive alternative of the traditional ship propulsion plants based on Diesel engines running with HFO for reducing both the plant operating cost and environmental footprint. The present study deals with the computational investigation of a large marine dual fuel (DF) engine of the four-stroke type for comparing its performance and emissions, in both diesel and gas mode operation by using the commercial software GT-ISE. The engine diesel model was initially set up and calibrated to adequately represent the engine operation. Subsequently, the engine dual fuel model was further developed by considering the injection of two different fuels; methane in the cylinder inlet ports and pilot diesel fuel into the engine cylinders. The derived results were analysed for revealing the differences of the engine performance and emissions at each operating mode. In addition, the turbocharger matching was investigated and discussed to enlighten the turbocharging system challenges due to the completely different air−fuel ratio requirements in diesel and gas modes, respectively. Finally, parametric simulations were performed for gas mode operation at different loads by varying pilot fuel injection timing, inlet valve closing and inlet manifold boost pressure, aiming to identify the engine settings that simultaneously reduce CO2 and NOx emissions considering the air−fuel ratio operation window limitations. The parametric study results are discussed to infer the engine optimal settings.

Women with renal disease have menstrual and gonadal dysfunction manifesting as hormonal imbalance. Anti-Müllerian hormone (AMH) is a potential measure of ovarian reserve. We examined circulating AMH concentrations in young women with renal failure, determined associations with clinical characteristics, and compared AMH with age-matched healthy individuals. AMH was measured in 77 women: 26 had chronic kidney disease (CKD), 26 were on haemodialysis (HD), and 25 had a kidney transplant. Random AMH levels were highest in women on HD [HD 2.9 (1.1–5.2), CKD 1.6 (0.7–2.2), transplant 1.5 (1.0–4.2) ng/ml]. On multiple linear regression, AMH was 53% higher [95% CI 0.20–0.98, P = 0.002] in women on HD and decreased by 20% per 5-year increase in age (P < 0.001). AMH was 43% lower in women with renal failure compared with 600 age-matched controls [1.7 (0.9–3.8) versus 3.0 (1.9–5.0) ng/ml, P < 0.001]; however, we found no difference in AMH between those on HD and healthy individuals [2.9 (1.1–5.2) versus 3.0 (1.9–5.0) ng/ml]. AMH may be a useful biomarker in female renal patients with non-dialysis dependent renal disease pursuing pregnancy. In contrast, AMH levels are higher in HD but unlikely to reflect ovarian reserve.

Although kidney transplantation is the treatment of choice for suitable patients with end-stage kidney disease, approximately 25% of chronic kidney disease (CKD) patients have peripheral arterial disease (PAD) ([1][1]). Computed tomography angiography (CTA) can identify patients requiring

BACKGROUND: Ferumoxytol is approved for use in the treatment of iron deficiency anemia, but it can serve as an alternative to gadolinium-based contrast agents. On the basis of postmarketing surveillance data, the Food and Drug Administration issued a black box warning regarding the risks of rare but serious acute hypersensitivity reactions during fast high-dose injection (510 mg iron in 17 seconds) for therapeutic use. Whereas single-center safety data for diagnostic use have been positive, multicenter data are lacking. PURPOSE: To report multicenter safety data for off-label diagnostic ferumoxytol use. MATERIALS AND METHODS: The multicenter ferumoxytol MRI registry was established as an open-label nonrandomized surveillance databank without industry involvement. Each center monitored all ferumoxytol administrations, classified adverse events (AEs) using the National Cancer Institute Common Terminology Criteria for Adverse Events (grade 1–5), and assessed the relationship of AEs to ferumoxytol administration. AEs related to or possibly related to ferumoxytol injection were considered adverse reactions. The core laboratory adjudicated the AEs and classified them with the American College of Radiology (ACR) classification. Analysis of variance was used to compare vital signs. RESULTS: Between January 2003 and October 2018, 3215 patients (median age, 58 years; range, 1 day to 96 years; 1897 male patients) received 4240 ferumoxytol injections for MRI. Ferumoxytol dose ranged from 1 to 11 mg per kilogram of body weight (≤510 mg iron; rate ≤45 mg iron/sec). There were no systematic changes in vital signs after ferumoxytol administration (P > .05). No severe, life-threatening, or fatal AEs occurred. Eighty-three (1.9%) of 4240 AEs were related or possibly related to ferumoxytol infusions (75 mild [1.8%], eight moderate [0.2%]). Thirty-one AEs were classified as allergiclike reactions using ACR criteria but were consistent with minor infusion reactions observed with parenteral iron. CONCLUSION: Diagnostic ferumoxytol use was well tolerated, associated with no serious adverse events, and implicated in few adverse reactions. Registry results indicate a positive safety profile for ferumoxytol use in MRI. © RSNA, 2019 Online supplemental material is available for this article.

No abstract available.

Background: Maritime transportation accounts for around 80% of the world freight movements, remarkably contributing to the global environmental footprint. Dual fuel engines, running on both gaseous and liquid fuels, represent a viable way toward the reduction of emissions at the cost of additional complexity in monitoring activities. Motivation: Data-driven methods represent the frontier in research and in maritime industrial applications, and they usually require a large amount of labelled data, i.e., sensor measurements plus the associated engine status usually annotated by human operators, which are costly and seldomly available in the wild. Unlabelled samples, instead, are commonly, cheaply, and readily available. Hypothesis: The enabling technology for data-driven methods is the availability of a network of sensors and an automation system able to capture and store the associated stream of data. Methods: In this paper, we design and propose multiple alternatives toward the weakly supervised marine dual fuel engines data-driven monitoring. To this aim, we will rely on a Digital Twin of the dual fuel engine or on novelty detection algorithms and we will compare them against state-of-the-art fully supervised approaches. Results: Results on data generated from a real-data validated simulator of a marine dual fuel engine demonstrate that the proposed weakly supervised monitoring approaches lead to a negligible loss in accuracy compared to costly and often unfeasible fully supervised ones supporting the validity of the proposal for its application in the wild. Conclusion: The main outcome is a guideline for selecting the best data-driven dual fuel engine monitoring method according to the available data.

Female renal transplant recipients of childbearing age may ask what the outcomes are for pregnancy and whether pregnancy will affect graft function. We analyzed obstetric and transplant outcomes among renal transplant recipients in our center who have been pregnant between 1973 and 2013. A case-cohort study was performed identifying 83 pairs of pregnant and non-pregnant controls matched for sex, age, transplant vintage, and creatinine. There were 138 pregnancies reported from 89 renal transplant recipients. There were live births in 74% of pregnancies with high prevalence of prematurity (61%), low birth weight (52%), and pre-eclampsia (14%). Lower eGFR (OR 0.98; p = 0.05) and higher uPCR (OR 1.86; p = 0.02) at conception were independent predictors for poor composite obstetric outcome. Lower eGFR (OR 0.98; p = 0.04), higher uPCR (OR 1.50; p = 0.04), and live organ donation (OR 0.35; p = 0.02) were predictors of ≥20% loss of eGFR between immediately pre-pregnancy and one yr after delivery. There was no difference in eGFR at one, five, and 10 yr in pregnant women compared with non-pregnant controls and a pregnancy was not associated with poorer 10-yr transplant or 20-yr patient survival. Despite high rates of obstetric complications, most women had successful pregnancies with good long-term transplant function.

Dual fuel engines constitute a viable solution for enhancing the environmental sustainability of the shipping operations. Although these engines comply with the Tier III NOx emissions regulations when operating at the gas mode, additional measures are required to ensure such compliance at the diesel mode. Hence, this study aimed to optimise the settings of a marine four-stroke dual fuel (DF) engine equipped with exhaust gas recirculation (EGR) and air bypass (ABP) systems by employing simulation and optimisation techniques, so that the engine when operating at the diesel mode complies with the ‘Tier III’ requirements. A previous version of the engine thermodynamic model was extended to accommodate the EGR and ABP systems modelling. Subsequently, a combination of optimisation techniques including multiobjective genetic algorithms (MOGA) and design of experiments (DoE) parametric runs was employed to identify both the engine and the EGR/ABP systems settings with the objective to minimise the engine brake specific fuel consumption and reduce the NOx emissions below the Tier III limit. The derived simulation results were employed to analyse the EGR system involved interactions and their effects on the engine performance and emissions trade-offs. A sensitivity analysis was performed to reveal the interactions between considered engine settings and quantify their impact on the engine performance parameters. The derived results indicate that EGR rates up to 35% are required, so that the investigated engine with EGR and ABP systems, when operating at the diesel mode, achieves compliance with the ‘Tier III’ NOx emissions, whereas the associated engine brake specific fuel consumption penalty is up to 8.7%. This study demonstrates that the combination of EGR and ABP systems can constitute a functional solution for achieving compliance with the stringent regulatory requirements and provides a better understating of the underlined phenomena and interactions of the engine subsystems parameters variations for the investigated engine equipped with EGR and ABP systems.

This study aims at developing an integrated model that combines detailed engine thermodynamic modelling and the control system functional modelling paving the way towards the development of high-fidelity digital twins. To sufficiently represent the combustion process, a multi-Wiebe function approach was employed, whereas a database for storing the combustion model parameters was developed. The developed model was employed for the systematic investigation of a marine four-stroke dual fuel engine response during demanding transient operation with mode switching and load changes. The derived results were analysed to identify the critical engine components and their effect on the engine operational limitations. The results demonstrate that the developed model can sufficiently represent the engine and its subsystems/components behaviour and effectively capture the engine control system&rsquo, s functionality. The appropriate turbocharger matching along with the sufficient design of the exhaust gas waste gate valve and fuel control systems are crucial for ensuring the smooth engine operation of dual fuel engines.

Traditional contrast-enhanced methods for scanning blood vessels using magnetic resonance imaging (MRI) or CT carry potential risks for patients with advanced kidney disease. Ferumoxytol is a superparamagnetic iron oxide nanoparticle preparation that has potential as an MRI contrast agent in assessing the vasculature. Twenty patients with advanced kidney disease requiring aorto-iliac vascular imaging as part of pre-operative kidney transplant candidacy assessment underwent ferumoxytol-enhanced magnetic resonance angiography (FeMRA) between December 2015 and August 2016. All scans were performed for clinical indications where standard imaging techniques were deemed potentially harmful or inconclusive. Image quality was evaluated for both arterial and venous compartments. First-pass and steady-state FeMRA using incremental doses of up to 4 mg/kg body weight of ferumoxytol as intravenous contrast agent for vascular enhancement was performed. Good arterial and venous enhancements were achieved, and FeMRA was not limited by calcification in assessing the arterial lumen. The scans were diagnostic and all patients completed their studies without adverse events. Our preliminary experience supports the feasibility and utility of FeMRA for vascular imaging in patients with advanced kidney disease due for transplant listing, which has the advantages of obtaining both arteriography and venography using a single test without nephrotoxicity. • Evaluation of vascular disease is important in planning kidney transplantation. • Standard vascular imaging methods are often problematic in kidney disease patients. • FeMRA has the advantage of arteriography and venography in a single test. • FeMRA is safe and non-nephrotoxic. • FeMRA is not limited by arterial calcification.

Background: Guidelines encourage early arteriovenous (AV) fistula (AVF) planning for haemodialysis (HD). The aim of this study was to estimate the likelihood of sustained AV access use taking into account age, sex, comorbidity, anatomical site of first AVF and, for pre-dialysis patients, eGFR and proteinuria. Methods: 1,092 patients attending our centre who had AVF as their first AV access procedure between January 1, 2000 and August 23, 2012 were identified from the electronic patient record. The primary end-point was time to first sustained AV access use, defined as use of any AV access for a minimum of 30 consecutive HD sessions. Results: 52.9% (n = 578) of the patients ultimately achieved sustained AV access use. The main reasons for AV access non-use were AVF failure to mature and death. The 3-year Kaplan-Meier probability of sustained AV access use was 68.8% for those not on renal replacement therapy (RRT) (n = 688) and 74.2% for those already on RRT (n = 404) at the time of first AVF. By multivariate analysis in patients not on RRT, male sex (HR 2.22; p < 0.001), uPCR (HR 1.03; p = 0.03) and eGFR (hazard ratio, HR 0.85; p < 0.001) were independent predictors of AV access use. In patients already on RRT, age (HR 0.98; p < 0.001) and peripheral vascular disease (HR 0.48; p = 0.02) were independent predictors of AV access use. Conclusion: Our data suggest that refinement of the current guideline for timing of AV access creation in planning RRT is justified to take into account individual factors that contribute to the likelihood of technical success and clinical need.

Continuously increasing environmental demands in conjunction with the planned strong penetration of the LNG, render the use of LNG as an attractive alternative marine fuel. In this framework, the traditional ship propulsion plants based on Diesel engines running with HFO, should be revisited and compared to the more efficient and environmentally friendly propulsion systems that use dual fuel engines. The present study deals with the computational investigation of a marine four-stroke dual fuel (DF) engine, in both diesel and DF mode operation. The engine model was set up in a commercial software and used to compare the performance and emissions of the investigated engine operation at steady state conditions. The engine diesel mode was initially set up and the model was calibrated to adequately represent the engine operation. Subsequently, the engine dual fuel model was set up by considering the injection of two different fuels; methane and pilot diesel fuel. The derived results were analysed for revealing the differences of the engine performance and emissions at each engine mode. In addition, the turbocharger matching at each mode is investigated revealing the challenges due to the completely different air-fuel ratio strategies used in diesel and dual fuel modes, re-spectively.

Severe acute kidney injury (AKI) among hospitalized patients often necessitates initiation of short-term dialysis. Little is known about the long-term outcome of those who recover to normal renal function. The aim of this study was to determine the long-term renal outcome of patients experiencing AKI requiring dialysis secondary to hypoperfusion injury and/or sepsis who recovered to apparently normal renal function.All adult patients with AKI requiring dialysis in our centre between 1 January 1980 and 31 December 2010 were identified. We included patients who had estimated glomerular filtration rate (eGFR)60 mL/min/1.73 m 2 12 months or later after the episode of AKI. Patients were followed up until 3 March 2015. The primary outcome was time to chronic kidney disease (CKD) (defined as eGFR persistently 60 mL/min/1.73 m 2 ) from first dialysis for AKI.Among 2922 patients with a single episode of dialysis-requiring AKI, 396 patients met the study inclusion criteria. The mean age was 49.8 (standard deviation 16.5) years and median follow-up was 7.9 [interquartile range (IQR) 4.8-12.7] years. Thirty-five (8.8%) of the patients ultimately developed CKD after a median of 5.3 (IQR 2.8-8.0) years from first dialysis for AKI giving an incidence rate of 1 per 100 person-years. Increasing age, diabetes and vascular disease were associated with higher risk of progression to CKD [adjusted hazard ratios (95% confidence interval): 1.06 (1.03, 1.09), 3.05 (1.41, 6.57) and 3.56 (1.80, 7.03), respectively].Recovery from AKI necessitating in-hospital dialysis was associated with a very low risk of progression to CKD. Most of the patients who progressed to CKD had concurrent medical conditions meriting monitoring of renal function. Therefore, it seems unlikely that regular follow-up of renal function is beneficial in patients who recover to eGFR 60 mL/min/1.73 m 2 by 12 months after an episode of AKI.

The waterborne transport in the Philippines has been a sensitive subject amplified by the lack of rules and regulations to restrict ship-owners profit-driven decisions, leading to overloading, with significant impact on ship stability. Most of the Tier-II vessels are using solid ballast to balance trim and increase static stability at the expense of freeboard. To improve matters whilst facilitating the currently adopted process, solutions are required that offer additional buoyancy with increased stability. To this end, a solution is proposed here through the addition of sponsons, providing the required level of intact stability and residual floatability/stability, using a typical Ro-Pax. In this paper, a case study is presented to demonstrate the validity of the proposed solution.

Kidney transplantation is the optimal treatment for patients with end stage renal disease (ESRD) who would otherwise require dialysis. Patients with ESRD are at dramatically increased cardiovascular (CV) risk compared to the general population. As well as improving quality of life, successful transplantation accords major benefits by reducing cardiovascular risk in these patients. Worldwide, cardiovascular disease remains the leading cause of death with a functioning graft and therefore is a leading cause of graft failure. This review focuses on the mechanisms underpinning excess cardiovascular morbidity and mortality and current evidence for improving cardiovascular risk in kidney transplant recipients. Conventional cardiovascular risk factors such as hypertension, diabetes mellitus, dyslipidaemia, and pre-existing ischaemic heart disease are all highly prevalent in this group. In addition, kidney transplant recipients exhibit a number of risk factors associated with pre-existing renal disease. Furthermore, complications specific to transplantation may ensue includingreduced graft function, side effects of immunosuppression and post transplantation diabetes mellitus. Strategies to improve cardiovascular\ud outcomes post transplantation may include pharmacological intervention including lipid lowering or antihypertensive therapy, optimisation of graft function, lifestyle intervention and personalising immunosuppression to the\ud individual patients risk profile.

The apolipoprotein E single-nucleotide polymorphisms are among the potential candidate genes that may serve as modulators in susceptibility to essential hypertension. In an effort to clarify earlier inconclusive results, we performed a meta-analysis of population-based case–control genetic association studies. Random-effects methods were applied on summary data in order to combine the results of the individual studies. We identified in total 45 studies, including 13 940 hypertensive cases and 16 364 controls. The contrast of E4 carriers versus non-carriers yielded an overall odds ratio (OR) of 1.16 (95% confidence interval (CI): 1.02, 1.31), whereas the contrast of E4 allele versus the others in a subtotal of 6617 cases and 7330 controls, yielded an OR of 1.39 (95% CI: 1.12, 1.72). There was moderate evidence of publication bias in both contrasts, which was eliminated after excluding studies not in Hardy–Weinberg equilibrium. Subgroup analyses revealed that significant estimates arose from studies on Asian populations, as opposed to the Caucasian ones. Furthermore, no evidence of publication bias was demonstrated in the comparisons within this subgroup. Our results are consistent with recent meta-analyses but show that the association is weaker than that has been previously demonstrated. Further studies are needed in order to fully address questions about the etiological mechanism of the particular association, as well as to study the effect in populations of African descent.

Introduction Fertility rapidly returns to women after successful kidney transplantation. The aim of this study was to collect information about pregnancy, delivery and renal outcomes among all kidney transplant recipients in our centre. Methods Pregnant women with a kidney transplant were identified through our prospectively maintained electronic patient record and case-notes between January 1, 1970 and February 28, 2013. We retrospectively analysed 40 years of pregnancy-related outcomes from 138 pregnancies reported from 89 kidney transplant recipients. Results Mean ages at the time of transplantation and pregnancy were 25.2 years and 30.3 years, respectively. Outcomes included 102 (73.9%) live births, 23 (16.7%) miscarriages, 8 (5.8%) terminations, 2 (1.4%) stillbirths, and 3 (2.2%) ectopic pregnancies. There were live births in 73.9% of pregnancies, with a high prevalence of preterm and caesarean deliveries (59.8% and 88.5%, respectively). Preexisting hypertension was present in 56 patients (40.6%) and preeclampsia was observed in 8.7% of pregnancies. Seven patients (5.1%) had an episode of acute rejection during pregnancy (three of which resulted in transplant failure). Mean age at conception, time interval between transplantation and pregnancy, 10-year incidence of live and preterm births (per prevalent pregnancies in kidney transplant recipients) remained unchanged over the last four decades (1970–1980, 1980–1990, 1990–2000, and 2000–2010). Conclusion The majority of pregnancies in renal transplant recipients have a good outcome but with increased risk of miscarriages, preterm and caesarean deliveries. Despite advances in immunosuppression, the incidence of live and preterm births has not changed over the last four decades in our unit.

The present study focuses on the modelling of a marine dual fuel engine and its control system with an aim to study the engine response at transient conditions and identify and discuss potential safety implications. This investigation is based on an integrated engine model developed in GT-ISE™ software, capable of predicting the steady state performance as well as the transient response of the engine. This model includes the appropriate modules for realising the functional modelling of the engine control system to implement the ordered engine load changes as well as switching the engine operating mode. The developed model is validated against available published data. Subsequently, two test cases with fuel changes, from gas to diesel and diesel to gas were simulated and the derived results were analysed for investigating the safety implications that may arise during operation. The results showed that the matching of the engine and the turbocharger as well as the exhaust gas waste gate control are critical factors for ensuring compressor surge free operation during fuel changes.