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We identified demographic, health and lifestyle factors associated with falls in adults aged 50-64 years from Australia, The Netherlands, Great Britain and Ireland. Nearly all factors were associated with falls, but there were differences between countries and between men and women. Existing falls prevention programs may also benefit middle-aged adults.Between ages 40-44 and 60-64 years, the annual prevalence of falls triples suggesting that middle age may be a critical life stage for preventive interventions. We aimed to identify demographic, health and lifestyle factors associated with falls in adults aged 50-64 years.Harmonised data were used from four population-based cohort studies based in Australia (Australian Longitudinal Study on Women's Health, n = 10,641, 51-58 years in 2004), Ireland (The Irish Longitudinal Study on Ageing, n = 4663, 40-64 years in 2010), the Netherlands (Longitudinal Ageing Study Amsterdam, n = 862, 55-64 years in 2012-13) and Great Britain (MRC National Survey of Health and Development, n = 2987, 53 years in 1999). Cross-sectional and prospective associations of 42 potential risk factors with self-reported falls in the past year were examined separately by cohort and gender using logistic regression. In the absence of differences between cohorts, estimates were pooled using meta-analysis.In cross-sectional models, nearly all risk factors were associated with fall risk in at least one cohort. Poor mobility (pooled OR = 1.71, CI = 1.34-2.07) and urinary incontinence (OR range = 1.53-2.09) were consistently associated with falls in all cohorts. Findings from prospective models were consistent. Statistically significant interactions with cohort and sex were found for some of the risk factors.Risk factors known to be associated with falls in older adults were also associated with falls in middle age. Compared with findings from previous studies of older adults, there is a suggestion that specific risk factors, for example musculoskeletal conditions, may be more important in middle age. These findings suggest that available preventive interventions for falls in older adults may also benefit middle-aged adults, but tailoring by age, sex and country is required. more...

Background Choledochalmalformation (CM) is a rare medical condition of which 80% are diagnosed in pediatric patients. There are several important controversies regarding diagnostic workup, management, and follow-up in these pediatric patients. To assess preferences and practices of Dutch pediatric surgeons regarding the diagnostic procedures, management, and follow-up of children with CM we conducted an electronic survey.Methods A questionnaire was sent to all the pediatric surgeons working in the academic centers and the only community hospital with a pediatric surgery service. The questionnaire included, items regarding incidence, diagnostic workup, interval between diagnosis and surgery, surgical techniques, and follow-up. We also assessed whether personal exposure influenced the preferences and practices.Results Overall 22 out of the 31 (71%) Dutch pediatric surgeons returned the questionnaire. Total 15 out of 22 (68%) encountered CM up to 2 times/y, whereas 7 out of 22 (32%) encountered it more than 2 times/y. Indications for surgery were significantly different between surgeons who encountered CM > 2 time/y versus those who did not: 6/6 (100%) of surgeons encountering CM > 2 times/y considered the presence of an asymptomatic CM an indication for surgery versus 5/14 (36%) of the pediatric surgeons who encountered a CM up to 2 times/y (p = 0.01). Overall 12 out of the 22 (55%) respondents preferred surgery between 6 months and 2 years of age. The amount of exposure did not differ in preferred age at surgery or surgical technique. In the symptomatic child 10/22 (45%) of respondents preferred surgery within 3 months. Overall 7/22 (32%) favored laparoscopic resection. Hepaticojejunostomy with Roux-en-Y reconstruction was the preferred reconstruction for all the respondents. One-third stated that they never performed a parenchyma resection. Follow-up was limited to 10 years in almost half of the respondents.Conclusion Dutch pediatric surgeons demonstrate a wide variety of opinions regarding diagnostic workup, treatment, and follow-up of CM. Whilemost surgeons encounter CM up to 2 times/y, there is an association between exposure and several of the outcome parameters. Some of the answers are not in line with the expert opinion. This demonstrates that there is a need for evidence-based (inter)national guidelines regarding the diagnostic approach, management, and follow-up. more...

Little is known about the achievement of developmental milestones (i.e., COL) after pediatric liver transplantation. The aim of this study was to examine the COL of young adults who underwent a liver transplantation during childhood and to compare it to healthy peers. Furthermore, we studied factors possibly related to their COL. COL was assessed using the CLQ, which assesses the achievement of developmental milestones (autonomy, psychosexual, social, and antisocial development) and risk behavior (substance abuse and gambling). Sociodemographic characteristics and clinical data were collected using the prospective institutional liver transplantation database. A total of 39 young adults who underwent a liver transplantation at the UMCG in their childhood completed the CLQ. They achieved fewer milestones with regard to autonomy, psychosexual, and social development compared to healthy peers, and they reported less risk behavior. Neither age at the time of study nor age at the time of transplantation was significantly correlated with any of the COL subscales. Young adults show delay in reaching developmental milestones in every dimension after a liver transplantation during their childhood. more...

Non-linear, radially global, turbulence simulations of ASDEX Upgrade (AUG) plasmas are performed and the nonlinear generated intrinsic flow shows agreement with the intrinsic flow gradients measured in the core of Ohmic L-mode plasmas at nominal parameters. Simulations utilising the kinetic electron model show hollow intrinsic flow profiles as seen in a predominant number of experiments performed at similar plasma parameters. In addition, significantly larger flow gradients are seen than in a previous flux-tube analysis (Hornsby et al {\it Nucl. Fusion} (2017)). Adiabatic electron model simulations can show a flow profile with opposing sign in the gradient with respect to a kinetic electron simulation, implying a reversal in the sign of the residual stress due to kinetic electrons. The shaping of the intrinsic flow is strongly determined by the density gradient profile. The sensitivity of the residual stress to variations in density profile curvature is calculated and seen to be significantly stronger than to neoclassical flows (Hornsby et al {\it Nucl. Fusion} (2017)). This variation is strong enough on its own to explain the large variations in the intrinsic flow gradients seen in some AUG experiments. Analysis of the symmetry breaking properties of the turbulence shows that profile shearing is the dominant mechanism in producing a finite parallel wave-number, with turbulence gradient effects contributing a smaller portion of the parallel wave-vector. more...

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The liver transplantation program of the University Medical Center Groningen in the Netherlands was started in 1979, making it one of the first programs worldwide. During the past 36 years, a total of 1478 liver transplantations have been performed, 459 of which were in children. One of the first patients transplanted in 1979 is still alive and is one of the longest surviving patients after liver transplantation worldwide. During the last decade, an increasing number of donation after circulatory death (DCD) donor livers have been accepted for transplantation. Over 30% of the livers transplanted in Groningen come from DCD donors. These livers have an increased risk of developing biliary complications, such as non-anastomotic biliary strictures (NAS). One of the main research topics in Groningen has been the pathogenesis and prevention of NAS. In an attempt to reduce the incidence of NAS after liver transplantation, machine perfusion technology has been developed as an alternative to the traditional method of static cold storage. Researchers of the Groningen liver transplant team were the first in the world to report a method of ex situ normothermic machine perfusion of human donor livers. The efficacy and safety of various types of machine perfusion are currently studied in both animal models and clinical trials. A second line of research in Groningen focuses on alterations in the blood coagulation system in patients with liver disease and undergoing liver transplantation. Groningen researchers were the first to describe a 'rebalanced state' of the coagulation system in patients with liver disease, making them prone to both bleeding and thrombo-embolic complications. Clinicians and researchers at the Groningen liver transplant program will continue to collaborate with a shared focus and the aim to provide innovation and the highest level of care to patients with endstage liver disease. more...

Objective: To compare the burden of total hospitalization as a ratio of survival of staging laparoscopy versus prophylactic bypass surgery in patients with unresectable periampullary adenocarcinoma.Background: Periampullary adenocarcinoma is an aggressive cancer with up to 35% of the patients at surgery found to be unresectable. Palliative prophylactic surgical bypass versus endoscopic stenting has been addressed by randomized controlled trials, but none reported on the burden of hospitalization.Methods: From a prospective database all patients with periampullary adenocarcinomas with a preoperative patent biliary stent and absent gastric outlet obstruction, but found unresectable during surgery, were analysed. They underwent a staging laparoscopy only versus prophylactic palliative bypass surgery. In-hospital days of the initial admission as well as all consecutive admission days during the remaining life span were compared both in absolute numbers and as relative impact.Results: The inclusion criteria were met by 205 patients. Of these 131 patients underwent a staging laparoscopy detecting metastases in 21 patients. In 184 laparotomies 54 patients underwent prophylactic palliative bypass surgery for unresectable disease. Median total in-hospital-stay in the Laparoscopy Group was 3 days versus 11 days in the Palliative Bypass Group (p = 0.0003). Patients with metastatic disease found during laparoscopy stayed 3.5% of the remaining life time in hospital vs. 10.0% (p = 0.029) in patients with metastatic disease who underwent bypass surgery.Conclusions: Staging laparoscopy and early discharge in patients with metastatic peri-ampullary carcinoma resulted in reduced hospitalization, both in absolute number of days and as a rate of survival time. (C) 2014 Elsevier Ltd. All rights reserved. more...

The interplay between an external torque and spontaneously occurring mesoscale structures, known as staircases, is investigated. Gyrokinetic simulations show that the E × B shear connected with the external torque does not simply add to the shear of the mesoscale structures. A positive (negative) externally forced E × B shear leads to a broadening of the positive (negative) region of the staircase but does not significantly change the plateau value or the narrow zero shear layer. In consequence, while the space and time averaged shearing rate is enhanced by the external torque, there is little or no effect on the turbulent transport. This raises doubts about the importance of driven or intrinsic rotation as a means to improve plasma confinement close to the stability threshold.The interplay between an external torque and spontaneously occurring mesoscale structures, known as staircases, is investigated. Gyrokinetic simulations show that the E × B shear connected with the external torque does not simply add to the shear of the mesoscale structures. A positive (negative) externally forced E × B shear leads to a broadening of the positive (negative) region of the staircase but does not significantly change the plateau value or the narrow zero shear layer. In consequence, while the space and time averaged shearing rate is enhanced by the external torque, there is little or no effect on the turbulent transport. This raises doubts about the importance of driven or intrinsic rotation as a means to improve plasma confinement close to the stability threshold. more...

INTRODUCTION: Choledochal malformations (CMs) are increasingly diagnosed antenatally. There is a dilemma between early surgery to prevent CM-related symptoms and postponing surgery to reduce complications. We aimed to identify the optimal timing of surgery in asymptomatic neonates with antenatally diagnosed CM and to identify predictors for development of symptoms.METHODS: Using the Netherlands Study group on CHoledochal Cyst/malformation (NeSCHoc) we retrospectively collected demographic, biochemical and surgical data from all Dutch patients with an antenatally detected CM.RESULTS: Between 1989 and 2014, antenatally suspected CM was confirmed in 17 patients at a median age of 10days (1day-2months). Four patients developed symptoms directly after birth (24%). Thirteen patients (76%) remained asymptomatic. Two of these progressed to symptoms before surgical intervention at 0.7 and 2.1months resp. Postoperatively, four patients developed short-term complications and three developed long-term complications. Patients 5.6kg (0%, p=0.02).CONCLUSION: When not symptomatic within the first days of life, the majority of children with antenatally detected CM remains asymptomatic. Surgery might safely be delayed to the age of 6months or a weight of 6kg. Postponing surgery in the clinically and biochemical asymptomatic patient might decrease the complication rate.LEVELS OF EVIDENCE: Level III. more...

To describe the development, validation, and findings of a patient experience questionnaire across 7 types of residential and ambulatory mental health care services. Thirty-five items were hypothesized to cover information, participation, therapeutic relationship, personalized care, organization and collaboration, safety, patient rights, outcomes of care, and discharge preparation and after-care. Also included were 2 overall rating items (scoring and recommending the organization). This Dutch questionnaire was applied in 79 organizations in Belgium (N patients = 5,168). Exploratory structural equation modelling was conducted on a random split-half sample to examine dimensionality. Confirmatory factor analysis and multiple group confirmatory factor analyses were conducted on the holdout sample to confirm dimensionality and assess measurement invariance across type of service and patient characteristics. Multilevel logistic regression models linking subscale top box scores to overall rating items were used to assess criterion validity. The hypothesized dimensionality was partly confirmed, and configural and scalar invariance were demonstrated across types of organizations and patient characteristics. Subscale scores were significantly associated with overall ratings. Process evaluation showed that participating organizations strongly support continued use of this questionnaire. This validated patient experience questionnaire supports comparison across organizations from different types of services to improve the quality of mental health care. more...

International audience; The progress made in understanding spontaneous toroidal rotation reversals in tokamaks is reviewed and current ideas to solve this ten-year-old puzzle are explored. The paper includes a summarial synthesis of the experimental observations in AUG, C-Mod, KSTAR, MAST and TCV tokamaks, reasons why turbulent momentum transport is thought to be responsible for the reversals, a review of the theory of turbulent momentum transport and suggestions for future investigations. more...

Frozen section analysis (FS) during cancer surgery is widely used to assess resection margins. However, in hilar cholangiocarcinoma (HCCA), FS may be less reliable because of the specific growth characteristics of the tumor. The aim of this study was to determine the accuracy and consequences of intraoperative FS of the proximal bile duct margins in HCCA. Between 1990 and 2014, 67 patients underwent combined extrahepatic bile duct resection and partial liver resection for HCCA with the use of FS. Sensitivity and specificity of FS was 68% and 97%, respectively. Seventeen of 67 patients (25%) displayed a positive bile duct margin at FS. The false‐negative rate was 16% (eight patients). Ten patients (15%) with a positive bile duct margin underwent an additional resection in an attempt to achieve negative margins, which succeeded in three patients (4%). However, only one of these three patients did not have concomitant lymph node metastases, which are associated with a poor prognosis by itself. The use of FS of the proximal bile duct is of limited clinical value because of the relatively low sensitivity, high risk of false‐negative results, and the low rate of secondary obtained tumor‐free resection margins. Supported by the literature, a new approach to the use of FS in HCCA should be adopted, reserving the technique only for cases in which a substantial additional resection is possible. more...

Background Repeat liver resection for colorectal liver metastases (CRLMs) is possible in a limited number of patients, with radiofrequency ablation (RFA) as an alternative for unresectable CRLMs. The aim of this study was to analyse survival rates with these interventions. Methods This was a database analysis of patients who underwent first and repeat interventions for synchronous and metachronous CRLMs between 2000 and 2013. Descriptive and survival statistics were calculated. Results Among 431 patients who underwent resection or RFA for CRLMs, 305 patients developed recurrences for which 160 repeat interventions (resection and/or RFA or ablative radiotherapy) were performed. In total, after 707 first or repeat interventions, 516 recurrences (73·0 per cent) developed, of which 276 were retreated curatively. At the time of first intervention, independent risk factors for death were lymph node-positive primary tumour (hazard ratio (HR) 1·40; P = 0·030), more than one CRLM (HR 1·53; P = 0·007), carcinoembryonic antigen level exceeding 200 ng/ml (HR 1·89; P = 0·020) and size of largest CRLM greater than 5 cm (HR 1·54; P = 0·014). The 5-year overall survival rates for liver resection and percutaneous RFA as first intervention were 51·9 and 53 per cent, with a median overall survival of 65·0 (95 per cent c.i. 47·3 to 82·6) and 62·1 (52·2 to 72·1) months, respectively. Conclusion RFA had good oncological outcomes in patients with unresectable CRLMs. Radiofrequency ablation is progressively more applied with each additional intervention. more...

Purpose: To investigate the course of life of young adults diagnosed with biliary atresia (BA) in infancy by comparing patients who did and did not underwent transplantation with an age-matched Dutch reference group.Methods: All patients from the Dutch BA registry, aged > 18 years, were invited to complete the course of life questionnaire.Results: Forty patients participated (response = 74%). Twenty-five had not undergone transplantation; 15 had undergone orthotopic liver transplantation. One significant between-group difference was found, namely in substance use and gambling. BA patients who underwent transplantation reported less use than the reference group (p = .01, moderate effect size). Additional moderate effect sizes were found for differences in psychosexual and social development and antisocial behavior. Patients who underwent transplantation had lower scores than one or both other groups.Conclusions: Development of BA survivors who did not undergo transplantation seems not delayed, whereas that of transplanted patients does seem somewhat delayed. However, patients who underwent transplantation display less risk behavior. Larger samples are necessary to confirm these findings. (C) 2012 Society for Adolescent Health and Medicine. All rights reserved. more...

Mentalisation-based treatment requires of the group therapist special competencies. He is responsible for maintaining the focus on mentalisation and regulating the level of anxiety in the group, having in mind the primitive modi of psychic functioning. He will promote the recognition, expression and sharing of feelings in contact, staying in the here and now of his own mind and the mind of the other. Psychodynamic group therapy aimed at mentalisation makes use of knowledge of group dynamics, but adds a specific way of thinking and acting to it, which includes the ‘not knowing stance’, and refraining from classic ways of intervening, such as interpretation. more...

This paper investigates the influence of turbulent dynamics on the neo-classical equilibrium in a tokamak, with an emphasis on the turbulence driven stationary electric current. The neo-classical solution is evaluated using the Hirschmann-Sigmar formalism, in which the turbulent dynamics enter as a forcing term. The latter forcing terms are evaluated through time averages of gyro-kinetic turbulence simulations and are linked with the velocity non-linearity in the gyro-kinetic equation. The time averaged turbulent forcing terms connected with the velocity non-linearity provide a non-negligible current drive, despite being a correction of second order in the normalized Larmor radius. For ITG turbulence, the force exerted due to the heat flux balance is the dominant contribution to the current. The parallel fluctuations of electron density/temperature and the electrostatic potential drive the majority of the current, which is in magnitude comparable to the bootstrap current in the kinetic cyclone base case and increases the total current by a few percent in cases with an experimentally relevant heat flux. An up-down symmetry breaking mechanism is required for turbulent current drive, which is provided in this study by a background rotation or rotation gradient. Consequently, the current is nearly linear in the plasma rotation or its gradient.This paper investigates the influence of turbulent dynamics on the neo-classical equilibrium in a tokamak, with an emphasis on the turbulence driven stationary electric current. The neo-classical solution is evaluated using the Hirschmann-Sigmar formalism, in which the turbulent dynamics enter as a forcing term. The latter forcing terms are evaluated through time averages of gyro-kinetic turbulence simulations and are linked with the velocity non-linearity in the gyro-kinetic equation. The time averaged turbulent forcing terms connected with the velocity non-linearity provide a non-negligible current drive, despite being a correction of second order in the normalized Larmor radius. For ITG turbulence, the force exerted due to the heat flux balance is the dominant contribution to the current. The parallel fluctuations of electron density/temperature and the electrostatic potential drive the majority of the current, which is in magnitude comparable to the bootstrap current in the kinetic cyclone base case a... more...

Large scale structures in the E × B shearing rate, known as staircases, are shown to form in nonlinear gyro-kinetic turbulence simulations with kinetic electrons. However, in many cases, a small scale structure in the shearing rate is observed that appears to prevent the formation of staircases. The small scale structures are interpreted to be linked to the self-interaction of turbulent modes connected with the double periodic boundary conditions on the torus. The self-interaction is a newly discovered mechanism for zonal flow generation and is shown to scale proportional to the normalized Larmor radius. The mechanism is also affected by magnetic shear, being weaker at larger values.Large scale structures in the E × B shearing rate, known as staircases, are shown to form in nonlinear gyro-kinetic turbulence simulations with kinetic electrons. However, in many cases, a small scale structure in the shearing rate is observed that appears to prevent the formation of staircases. The small scale structures are interpreted to be linked to the self-interaction of turbulent modes connected with the double periodic boundary conditions on the torus. The self-interaction is a newly discovered mechanism for zonal flow generation and is shown to scale proportional to the normalized Larmor radius. The mechanism is also affected by magnetic shear, being weaker at larger values. more...

This paper investigates the so-called tertiary instabilities driven by the zonal flow in gyro-kinetic tokamak core turbulence. The Kelvin Helmholtz instability is first considered within a 2D fluid model and a threshold in the zonal flow wave vector kZF>kZF,c for instability is found. This critical scale is related to the breaking of the rotational symmetry by flux-surfaces, which is incorporated into the modified adiabatic electron response. The stability of undamped Rosenbluth-Hinton zonal flows is then investigated in gyro-kinetic simulations. Absolute instability, in the sense that the threshold zonal flow amplitude tends towards zero, is found above a zonal flow wave vector kZF,cρi≈1.3 ( ρi is the ion thermal Larmor radius), which is comparable to the 2D fluid results. Large scale zonal flows with kZF more...

Hepatic artery thrombosis (HAT) after pediatric orthotopic liver transplantation (OLT) is a serious complication resulting in bile duct necrosis and often requiring retransplantation. Immediate surgical thrombectomy/thrombolysis has been reported to be a potentially successful treatment for restoring blood flow and avoiding urgent retransplantation. The long-term results of this strategy remain to be determined. In 232 pediatric liver transplants, we analyzed long-term outcomes after urgent revascularization for early HAT. HAT developed in 32 patients (13.7%). In 16 children (50%), immediate surgical thrombectomy was performed in an attempt to salvage the graft. Fourteen patients (44%) underwent urgent retransplantation, and 2 (6%) died before further intervention. Immediate thrombectomy resulted in long-term restoration of the hepatic artery flow in 6 of 16 patients (38%) and in 1- and 5-year graft and patient survival rates of 83% and 67%, respectively. In 10 patients, revascularization was unsuccessful, and retransplantation was inevitable. The 1- and 5-year patient survival rates in this group decreased to 50% and 40%, respectively. After immediate retransplantation, the 5-year patient survival rate was 71%. In conclusion, immediate surgical thrombectomy for HAT after pediatric OLT results in long-term graft salvage in about one-third of patients. However, when thrombectomy is unsuccessful, long-term patient survival is lower than the survival of patients who underwent immediate retransplantation. more...

Objective: To evaluate whether a low postoperative platelet count is associated with a poor recovery of liver function in patients after partial liver resection.Background: Experimental studies in rodents have recently suggested that blood platelets play a critical role in the initiation of liver regeneration. It remains unclear whether platelets are also involved in liver regeneration in humans.Methods: In a series of 216 consecutive patients who underwent partial liver resection for colorectal liver metastases. we studied postoperative mortality and liver dysfunction in relation to the immediate postoperative platelet count. All patients had normal preoperative liver function and none of them had liver fibrosis or cirrhosis. Delayed postoperative recovery of liver function was defined as serum bilirubin > 50 mu mol/L or prothrombin time > 20 seconds at any time point between postoperative day I and 5.Results: Patients with a low ( 100(9)/L). A low immediate postoperative platelet count was identified as an independent risk factor of delayed postoperative recovery of liver function (OR, 11.5; 95% CL, 1.1-122.4; P = 0.04 in multivariate analysis).Conclusion: After partial liver resection, a low platelet count is an independent predictor of delayed postoperative liver function recovery and is associated with increased risk of postoperative mortality. These clinical findings are in accordance with the accumulating evidence from experimental studies, indicating that platelets play a critical role in liver regeneration. more...

This study assesses the relation between the anhepatic phase duration and the outcome after liver transplantation. Of 645 patients who underwent transplantation between 1994 and 2006, 194 were recipients of consecutive adult primary piggyback liver transplants using heart-beating donors. The anhepatic phase was defined as the time from the physical removal of the liver from the recipient to recirculation of the graft. Other noted study variables were the cold and warm ischemia times, donor and recipient age, donor and recipient body mass index, perioperative red blood cell (RBC) transfusion, indication for transplantation, and Model for End-Stage Liver Disease score. The primary outcome parameter was graft dysfunction, which was defined as either primary nonfunction or initial poor function according to the Ploeg-Maring criteria. The median anhepatic phase was 71 minutes (37-321 minutes). Graft dysfunction occurred in 27 patients (14%). Logistic regression analysis showed an anhepatic phase over 100 minutes [odds ratio (OR), 4.28], a recipient body mass index over 25 kg/m(2) (OR, 3.21), and perioperative RBC transfusion (OR, 3.04) to be independently significant predictive factors for graft dysfunction. One-year patient survival in patients with graft dysfunction was 67% versus 92% in patients without graft dysfunction (P more...

Currently, liver transplantation (LT) is an accepted method of treatment of end-stage liver disease, metabolic diseases with their primary defect in the liver and unresectable primary liver tumors. Surgical techniques in LT have evolved considerably over the past 40 yr. The developments have led to a safer procedure for the recipient reflected by continuously improving survival figures after LT. Also the new techniques offer the possibility of tailoring the operation to the needs and condition of the recipient as in partial grafting or in different revascularization techniques, or in techniques of biliary reconstructions. In addition, the new techniques such as split LT, domino transplantation and living donor LT have brought about an increase in the available grafts. In this review the evolution of surgical techniques in LT over the past 40 yr and their contribution to the current results are discussed. more...

International audience; It is shown that Ion Temperature Gradient turbulence close to the ă threshold exhibits a long time behaviour, with smaller heat fluxes at ă later times. This reduction is connected with the slow growth of long ă wave length zonal flows, and consequently, the numerical dissipation on ă these flows must be sufficiently small. Close to the nonlinear threshold ă for turbulence generation, a relatively small dissipation can maintain a ă turbulent state with a sizeable heat flux, through the damping of the ă zonal flow. Lowering the dissipation causes the turbulence, for ă temperature gradients close to the threshold, to be subdued. The heat ă flux then does not go smoothly to zero when the threshold is approached ă from above. Rather, a finite minimum heat flux is obtained below which ă no fully developed turbulent state exists. The threshold value of the ă temperature gradient length at which this finite heat flux is obtained ă is up to 30% larger compared with the threshold value obtained by ă extrapolating the heat flux to zero, and the cyclone base case is found ă to be nonlinearly stable. Transport is subdued when a fully developed ă staircase structure in the E x B shearing rate forms. Just above the ă threshold, an incomplete staircase develops, and transport is mediated ă by avalanche structures which propagate through the marginally stable ă regions. Published by AIP Publishing. more...

The present status of understanding of toroidal and poloidal momentum transport in tokamaks is presented in this paper. Similar energy confinement and momentum confinement times, i.e. tau(E)/tau(phi)approximate to 1 have been reported on several tokamaks. It is more important though, to study the local transport both in the core and edge plasma separately as, for example, in the core plasma, a large scatter in the ratio of the local effective momentum diffusivity to the ion heat diffusivity chi(phi eff)/chi(i.eff) among different tokamaks can be found. For example, the value of effective Prandtl number is typically around chi(phi eff)/chi(i.eff)approximate to 0.2 on JET while still tau(E)/tau(phi)approximate to 1 holds. Perturbative NBI modulation experiments on JET have shown, however, that a Prandtl number chi(phi)/chi(i) of around 1 is valid if there is an additional, significant inward momentum pinch which is required to explain the amplitude and phase behaviour of the momentum perturbation. The experimental results, i.e. the high Prandtl number and pinch, are in good qualitative and to some extent also in quantitative agreement with linear gyro-kinetic simulations. In contrast to the toroidal momentum transport which is clearly anomalous, the poloidal velocity is usually believed to be neo-classical. However, experimental measurements on JET show that the carbon poloidal velocity can be an order of magnitude above the predicted value by the neo-classical theory within the ITB. These large measured poloidal velocities, employed for example in transport simulations, significantly affect the calculated radial electric field and therefore the E x B flow shear and hence modify and can significantly improve the simulation predictions. Several fluid turbulence codes have been used to identify the mechanism driving the poloidal velocity to such high values. CUTIE and TRB turbulence codes and also the Weiland model predict the existence of an anomalous poloidal velocity, peaking in the vicinity of the ITB and driven dominantly by the flow due to the Reynold's stress. It is worth noting that these codes and models treat the equilibrium in a simplified way and this affects the geodesic curvature effects and geodesic acoustic modes. The neo-classical equilibrium is calculated more accurately in the GEM code and the simulations suggest that the spin-up of poloidal velocity is a consequence of the plasma profiles steepening when the ITB grows, following in particular the growth of the toroidal velocity within the ITB. more...

Since 1998 ASDEX Upgrade has developed stationary H-modes that routinely obtain confinement enhancement factors H98(y,2) > 1 and normalized beta, βN = 2–3. These discharges are characterized by a q-profile with low magnetic shear in the centre and q(0) ~ 1. New results presented here concentrate on extending the operational range of these improved H-modes at ASDEX Upgrade and extrapolating the results to ITER. Discharges are obtained at high density, over a wide range of plasma collisionality and with a first wall predominantly covered by tungsten coated carbon tiles. The performance is optimized for q95 ranging from 3 to 5. At q95 ~ 3 real time control of βN is used and in some cases ECCD to suppress NTM activity at low βN ~ 2. For the extrapolation to ITER, the fusion power is calculated using the same thermal beta (βN,th) and kinetic profile shapes as obtained in ASDEX Upgrade and setting ne/nGW = 0.85. The fusion gain that could be obtained is evaluated using different confinement scaling expressions. The results indicate that improved H-modes are a candidate for an ITER hybrid scenario or could extend ITER operation beyond what is currently foreseen using standard H-modes. more...

Between November 1982 and March 2006, 67 children with body weight 4.0 was 44%, 38%, 38%, and 30%, respectively (p = 0.02). In summary, patient survival in children with body weight

The relationship between design behaviours and successful design task completion is studied for multidisciplinary design teams. In this research, no observational methods such as audio–visual recordings or ethnographic fieldwork were used, as often the case in design research, but a questionnaire tapping critical behaviours was developed and statistically validated in two separate studies. In addition, this study presents a comprehensive view on the behaviour of design team members. The resulting Design Behaviour Questionnaire for Teams consists of 55 items divided into three main categories (‘design creation’, ‘design planning’, and ’design cooperation’) and 12 scales. more...

International audience; The collisional stabilisation via energy scattering and pitch-angle ă scattering of micro-instabilities in tokamak plasmas is investigated by ă means of gyrokinetic simulations with a special emphasis on the often ă neglected energy scattering operator. It is shown that in the linear ă regime energy scattering has a negligible effect on Ion Temperature ă Gradient (ITG) modes but enhances the stabilisation of Trapped Electron ă Modes (TEM) in presence of nonzero ion temperature and density ă gradients. This stabilisation is sensitive to the model used for the ă energy restoring term in the collision operator. The contributions of ă parallel and drift motion to the total growth rate in velocity space are ă used to characterize the complex stabilisation mechanisms behind ă pitch-angle and energy scattering for a range of relevant parameters ă such as the magnetic shear, the collisionality, the logarithmic density ă gradient, and the logarithmic ion temperature gradient. It is shown that ă depending on these parameters, energy scattering stabilisation of TEM ă can be either due to a decrease of the contribution from drifting ă trapped electrons or to an increase of the contribution from the ă parallel motion of passing electrons. Finally, for a standard ITG/TEM ă case, the effect of energy scattering on the nonlinear heat and particle ă fluxes is investigated. (C) 2015 AIP Publishing LLC. more...

This paper describes and further develops the understanding of toroidal momentum transport. Nonlinear gyro-kinetic simulations of the ion temperature gradient mode with adiabatic electrons show a strong coupling between the momentum and ion heat transport, with the ratio of the transport coefficients close to 1. Linear theory using a global description predicts an off-diagonal contribution to the momentum flux even in the absence of a radial electric field. The influence of the toroidal velocity gradient on the ion temperature profile is found to be small in the H-mode. These predictions are in qualitative agreement with experimental observations. more...

No consensus exists regarding the optimal reconstruction of the cavo-caval anastomosis in piggyback orthotopic liver transplantation (PB-LT). The aim of this study was to analyze our experience with end-to-side (ES) cavo-cavostomy. Outcome parameters were patient and graft survival and surgical complications. During the period 1995-2002 146 full-size PB-LT in 137 adult patients were performed with ES cavo-cavostomy without the routine use of temporary portocaval shunt (TPCS). In 12 patients (8%) this technique was used for implantation of second or third grafts. Veno-venous bypass was not used in any case and TPCS was performed only in eight patients (6%). One-, three- and five-yr patient and graft survival were 84%, 79% and 75%, and 81%, 74% and 69%, respectively. The median number of intraoperative transfusion of packed red blood cells (RBC) was 2.0 (range 0-33) and 30% of the patients (n = 43) did not require any RBC transfusion. Surgical complications of various types were observed after 49 LT (34%) and none of the complications was specifically related to the technique of ES cavo-cavostomy. Our experience indicates that PB-LT with ES cavo-cavostomy is a safe procedure, can safely be performed without the routine use of a TPCS, has a very low risk of venous outflow obstruction and can also be used effectively during retransplantations. more...

The exact frequency and clinical consequences of surgical hepatic injuries during organ procurement are unknown. We analyzed the incidence, risk factors, and clinical outcome of surgical injuries in 241 adult liver grafts. Hepatic injuries were categorized as parenchymal, vascular, or biliary. Outcome variables were bleeding complications, hepatic artery thrombosis (HAT), and graft survival. In 82 livers (34%), 96 injuries were detected. Most injuries were minor, but clinically relevant injuries were detected in 6.6% (16/241) of the livers. Fifty (21%) liver grafts had some degree of parenchymal or capsular injury, 40 (17%) had vascular injury, and 6 (2%) had an injury to the bile duct. Procurement region was the only risk factor significantly associated with surgical injury. The rate of hepatic artery injury was significantly higher in livers with aberrant arterial anatomy. Bleeding complications were found in 18% of patients who received livers with a parenchymal or capsular injury in contrast to 9% without parenchymal injury (P = 0.065). HAT was found in 23% of the patients who received a liver with arterial injury compared to 4% without arterial injury (P = 0.001). Overall graft survival rates were not significantly different for grafts with or without anatomical injury. In conclusion, surgical injuries of donor livers are an underestimated problem in liver transplantation and can be observed in about one-third of all cases. Clinically relevant injuries are detected in 6.6% of all liver grafts. Arterial injuries are associated with an increased risk of HAT. more...

Authors analyzed the differences in the outcome of two European liver transplant centers differing in case volume and experience. The first was the Transplantation and Surgical Clinic, Semmelweis University, Budapest, Hungary (SEB) and the second the University Medical Center Groningen, Groningen, The Netherlands (UMCG). We investigated if such differences could be explained. The 1-, 3- and 5-year patient survival in the UMCG was 86%, 80%, and 77% compared with 65%, 56%, and 55% in SEB. Graft survival at the same time points was 79%, 71%, and 66% in the UMCG and 62%, 55%, and 53% in SEB. Significant differences were present regarding the donor and recipient age, diagnosis mix, disease severity and operation variables, per-operative transfusion rate, vascular complications, postoperative infection rate, and need for renal replacement. To determine factors correlating with survival, a separate uni- and multivariate analysis was performed in each center individually, between study parameters and patient survival. In both centers, peri-operative red blood cell (RBC) transfusion rate was a significant predictor for patient survival. The difference in blood loss can be explained by different operation techniques and shorter operation time in SEB, with consequently less time spent on hemostasis. It was jointly concluded that measures to reduce blood loss by adapting the operation technique might lead to improved survival and reduced morbidity. more...

Relationships between team composition in terms of team members' Big Five personality traits and individual satisfaction with the team after project completion were researched. Questionnaires were filled out by 310 undergraduate students ( N= 68 teams) working on an engineering design assignment. Individual satisfaction with the team was regressed onto individual, dissimilarity, and interaction scores. A positive main effect was found for individual agreeableness and emotional stability and for dissimilarity in conscientiousness. A moderation of the main effect of dissimilarity was found for extraversion: Satisfaction with the team is negatively related to dissimilarity to the other team members only for members low in extraversion. more...

The bootstrap current in a tokamak plasma with a very small poloidal magnetic field near the magnetic axis (current hole) is computed with guiding centre particle simulations including a Monte Carlo model of pitch-angle scattering. We find that the bootstrap current is very small inside the current hole, while the parallel plasma flow is of similar size as the neoclassical flow due to the pressure gradient outside the current hole. more...

Significant progress has been made on ASDEX Upgrade during the last two years in the basic understanding of transport, in the extension of the improved H-mode in parameter space and towards an integrated operating scenario and in the development of control methods for major performance limiting instabilities. The important features were the understanding of particle transport and the control of impurity accumulation based on it, the satisfactory operation with predominantly tungsten-clad walls, the improved H-mode operation over density ranges and for temperature ratios covering (non-simultaneously) the ITER requirements on ν*, n/nGW and Te/Ti, the ELM frequency control by pellet injection and the optimization of NTM suppression by DC-ECCD through variation of the launching angle. From these experiments an integrated scenario has emerged which extrapolates to a 50% improvement in n T τ or a 30% reduction of the required current when compared with the ITER base-line assumptions, with moderately peaked electron and controllable high-Z density profiles. more...

The aim of the study was to assess whether there is a difference in outcome after sequential or simultaneous revascularization during orthotopic liver transplantation (OLT) in terms of patient and graft survival, mortality, morbidity, and liver function. The study population consisted of 102 adult patients with primary full-size piggyback OLT transplanted between January 1998 and December 2001. In 71 patients (70%) the grafts were sequentially reperfused after completion of the portal vein anastomosis and subsequent arterial reconstruction was performed (sequential reperfusion [SeqR] group). In 31 patients (30%) the graft was reperfused simultaneously via the portal vein and hepatic artery (simultaneous reperfusion [SimR] group). Patient and graft survival at 1, 3, and 6 months and at I year did not differ between the SeqR group and the SimR group. The red blood cell (RBC) requirements were significantly higher in the SimR group (5-5 units; range 0-20) in comparison to the SeqR group (2 units; range 0-19) (P = 0.02). Apart from a higher number of biliary anastomotic complications and abdominal bleeding complications in the SimR group in comparison to the SeqR group (13% vs. 2% and 19% vs. 6%, respectively; P = 0.06), morbidity was not different between the groups. No differences between the groups were observed regarding the incidence of primary nonfunction (PNF), intensive care unit stay, and acute rejection. This was also true for the severity of rejections. Postoperative recuperation of liver function was not different between the groups. In conclusion, no advantage of either of the 2 reperfusion protocols could be observed in this analysis, especially with respect to the incidence of ischemic type biliary lesions (ITBL). more...

The polarization current associated with a neoclassical tearing mode (NTM) is studied by means of drift kinetic δf simulations. This current has been invoked as a possible explanation for both the observed threshold for the minimum island size that can grow unstable and the scaling of the plasma pressure at the mode onset with the normalized gyroradius, even though the theory is not able to predict the island rotation direction and hence the role (whether stabilizing or destabilizing) of the polarization current for the island evolution. In the numerical approach presented in this paper, the island rotation frequency can be assigned as an input parameter and the corresponding behaviour of the current can be studied. The calculations are performed in toroidal geometry in the presence of a helical perturbation. It is found that kinetic effects lead to a sign reversal of the polarization current for rotation frequencies close to the diamagnetic frequency even for flat pressure profiles, thus influencing both the sign and size of the polarization-current contribution to the NTM evolution. more...

Recent studies provide convincing evidence that the anomalous transport in a tokamak is governed by the combination of ion temperature gradient and trapped electron mode turbulence. In this paper, we employ the theory-based transport model GLF23 to study the density profile formation in ITER. It is shown that the plasma density can be noticeably more peaked than is usually assumed. The peaking is mainly due to the curvature drift as described by the GLF model and, independently, by the turbulent equipartition theory. This results in an approximately 30% enhancement of the fusion power in comparison with the standard conjecture of the flat density profile. The physical background of this density peaking and its possible further impact on the reactor performance are also discussed. more...

The aim of this study was to analyze the effect of human leukocyte antigen (HLA) class I and HLA-DR mismatching, sharing cross-reactive antigen groups (CREGs), and sharing HLA-DR antigens on the outcome after pediatric liver transplantation. Outcome parameters were graft survival, acute rejection, and portal fibrosis. A distinction was made between full-size (FSLTx) and technical-variant liver transplantation (TVLTx). A total of 136 primary transplants were analyzed. The effect of HLA on the outcome parameters was analyzed by adjusted multivariate logistic and Cox regression analysis. HLA mismatches, shared CREGs, and shared HLA-DR antigens affected neither overall graft survival nor survival after FSLTx. Survival after TVLTx was superior in case of 2 mismatches at the HLA-DR locus compared to 0 or 1 mismatch (P = 0.01) and in case of no shared HLA-DR antigen compared to I shared HLA-DR antigen (P = 0.004). The incidence of acute rejection was not influenced by HLA. The incidence of portal fibrosis could be analyzed in 62 1-yr biopsies and was higher after TVLTx than FSLTx (P = 0.04). The incidence of portal fibrosis after TVLTx with 0 or 1 mismatch at the HLA-DR locus was 100% compared to 43% with 2 mismatches (P = 0.004). After multivariate analysis, matching for HLA-DR and matching for TVLTx were independent risk factors for portal fibrosis. In conclusion, an overall beneficial effect of HLA matching, sharing CREGs, or sharing HLA-DR antigens was not observed. A negative effect was present for HLA-DR matching and sharing HLA-DR antigens on survival after TVLTx. HLA-DR matching might be associated with portal fibrosis in these grafts. more...

The adenosine triphosphate (ATP)-binding cassette (ABC)-transporters ABCG5 and ABCG8 have been shown to mediate hepatic and intestinal excretion of cholesterol. In various (genetically modified) marine models, a strong relationship was found between hepatic expression of ABCG5/ABCG8 and biliary cholesterol content. Our study aimed to relate levels of hepatic expression of ABCG5 and ABCG8 to biliary excretion of cholesterol in man. From 24 patients who had received a liver transplant, bile samples were collected daily after transplantation over a 2-week period to determine biliary composition. Expression of ABCG5, ABCG8, MDR3, and BSEP was assessed by real-time polymerase chain reaction (PCR) in liver biopsy specimens collected before and after transplantation. Levels of hepatic ABCG5, ABCG8, and MDR3 messenger RNA (mRNA) were strongly correlated. After transplantation, the biliary secretion rate of cholesterol continuously increased, coinciding with gradual increases in bile salt and phospholipid secretion. In contrast, hepatic levels of ABCG5 and ABCG8 mRNA remained unchanged. Surprisingly, no correlation was found between the hepatic expression of ABCG5 and ABCG8 and rates of biliary cholesterol secretion, normalized for biliary phospholipid. secretion. As expected, the concentration of biliary phospholipids correlated well with MDR3 expression. In conclusion the strong relationship between ABCG5 and ABCG8 gene expression is consistent with the coordinate regulation of both genes, and in line with heterodimerization of both proteins into a functional transporter. Hepatic ABCG5/ABCG8 expression, at least during the early phase after transplantation, is not directly related to biliary cholesterol secretion in humans. This finding suggests the existence of alternative pathways for the hepatobiliary transport of cholesterol that are not controlled by ABCG5/ABCG8. more...

Background/Aims: Biliary strictures are a serious cause of morbidity after liver transplantation. We have studied the role of altered bile composition as a mechanism of bile duct injury after human liver transplantation.Methods: In 28 liver transplant recipients, bile samples were collected daily posttransplantation for determination of bile composition. Hepatic expression of bile transporters was studied before and after transplantation. Histopathological criteria as well as biliary concentrations of alkaline phosphatase (ALP) and gamma-glutamyltransferase (gamma-GT) were used to quantify bile duct injury.Results: Early after transplantation, bile salt secretion increased more rapidly than phospholipid secretion, resulting in high biliary bile salt/phospholipid ratio (BA/PL). In parallel with this, mRNA levels of the bile salt transporters NTCP and BSEP increased significantly after transplantation, whereas phospholipid translocator MDR3 mRNA levels remained unchanged. Bile duct injury correlated significantly with bile salt secretion and was associated with a high biliary BA/PL ratio.Conclusions: Bile salt secretion after human liver transplantation recovers more rapidly than phospholipid secretion. This results in cytotoxic bile formation and correlates with bile duct injury. These findings suggest that endogenous bile salts have a role in the pathogenesis of bile duct injury after liver transplantation. (C) 2004 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved. more...