1,123 research outputs found
Automated Identification and Tracking of Deformation Twin Structures in Molecular Dynamics Simulations
Deformation twinning significantly influences the microstructure, texture,
and mechanical properties of metals, necessitating comprehensive studies of
twin formation and interactions. While experimental methods excel at analyzing
individual samples, they often lack the capability for temporal analysis of
twinned structures. Molecular dynamics simulations offer a temporal dimension,
yet the absence of suitable tools for automated crystal twin identification has
been a significant limitation. In this article, we introduce a novel
computational tool integrated into the visualization and analysis software
OVITO. Our tool automates the identification of coherent twin boundaries, links
related twin boundaries, validates twin structures through orientation
analysis, and tracks twins over time, providing quantifiable data and enabling
in-depth investigations. Validation on a copper single crystal under shear
loading demonstrates successful tracking of various twins, revealing their
genesis and growth over multiple timesteps. This innovative approach promises
to advance the computational materials science domain by facilitating the study
of deformation twinning, offering profound insights into the behavior and
mechanical performance of materials
Case Control Study on Dialysis Arthropathy: The Influence of Two Different Dialysis Membranes: Data from the EDTA Registry
In a retrospective case control study the prevalence of signs and symptoms of dialysis osteoarthropathy was analysed. Cases and controls had received over 9 years of maintenance haemodialysis uninterrupted by peritoneal dialysis or transplantation. The cases comprised 55 patients treated predominantly with polyacrylonitrile (AN69) dialysers. They were compared to a matched group dialysed exclusively with cellulosic membranes. Over 60% of all patients, cases and controls, showed one or more signs of disabling osteoarthropathy, with joint pains occurring more frequently in the older age groups. Twenty-seven of the 55 cases who had received less than 2 years of cellulosic membrane dialysis followed by 7-12 years of AN69 dialysis tended to have a lower prevalence of joint pains, carpal-tunnel syndrome and bone cysts. However, no statistically significant differences were obtained compared to the matched control group dialysed exclusively on cellulosic membranes (mostly cuprophane). The remaining 28 cases, who had been treated for more than 2 years with cellulosic membranes preceding the longer treatment period with polyacrylonitrile dialysers, showed a prevalence similar to that of their cellulosic controls. This study thus shows little, if any, influence of the two types of membranes on the prevalence of signs and symptoms of β2-microglobulin amyloidosi
Rehabilitation of young adults during renal replacement therapy in Europe: The presence of disabilities
The aim of this study was to analyse rehabilitation during RRT in 617 young adults from different European countries who started dialysis or transplantation before the age of 15 years. The data were derived from the EDTA Registry patient data files and a special questionnaire that was sent to centres reporting to the EDTA Registry. The duration of RRT was more than 10 years in 63% of patients. Fifty-four percent were living with a functioning graft and 46% were on dialysis. The prevalence and severity of motor, hearing, sight, and mental disabilities were analysed retrospectively. They were found to vary according to primary renal disease and method oftreatment. One-third of patients had one or more disabilities at the start of RRT. Although disability status had changed in many patients by 31 December 1986, some disability remained in one-third of the patients available for study. Disabilities were recorded as mild in the majority of patients. Both improvement and worsening of motor and mental disability occurred more often than changes of hearing capacity and sight. It is concluded that prevention and treatment of disabilities need special attention in children and young adults on RRT in order to improve rehabilitatio
Successful pregnancies in women on renal replacement therapy: Report from the EDTA Registry
This study reports the geographical incidence of successful pregnancies in women on renal replacement therapy (RRT) and related information on gestation and clinical status of newborns. The impact of successful pregnancy on graft function was assessed by means of a retrospective case-control study. Since 1977 special questionnaires have been sent to each dialysis and transplant centre which reported babies born to mothers on RRT on the yearly centre questionnaire. After 10 years of data collection, a total of 490 pregnancies and 500 babies were available for analysis. A percentage of 88.4 of the babies were born to mothers with a functioning graft, 11.2% to mothers on chronic haemodialysis, and the remaining 0.4% to mothers on CAPD. Almost 50% of all successful pregnancies werereported from the UK. The number of successful pregnancies increased steadily and in parallel with the increasing number of females of childbearing age with a functioning renal transplant. The majority of mothers delivered at age 24-32. For transplanted mothers delivery occurred most commonly during the 3rd and 4th year after successful transplantation. In approximately 85% of cases the duration of pregnancy was shorter than the lower 10th percentile of normal. Birthweight was reduced in accordance with gestational age. Newborn mortality was 1.8%. Fifty-three mothers with a successful pregnancy in 1984-1987 were computer matched with controls according to a number of criteria. The serum creatinine concentration recorded in coded form at the end of each year on the individual EDTA patient questionnaire was used to assess changes in graft function. In 94% of these cases the serum creatinine, recorded 0-11 months before delivery, did not exceed 160 umol/1. Graft function deteriorated in 18% ofmothers as compared to 24% of controls. Twentyfour to 36 months postpartum, changes of serum creatinine were similar in test cases and controls, suggesting that a successful pregnancy does not adversely affect graft function if this was stable and well preserved at the time of conceptio
Factors influencing anaemia in dialysis patients. A special survey by the EDTA-ERA Registry
The European Dialysis and Transplantation Association—European Renal Association (EDTA-ERA) Registry conducted a special study on anaemia in dialysis patients because it seemed important to elucidate the various factors that influence the degree of anaemia and the use of regular transfusions in dialysis patients before the introduction of recombinant human erythropoietin (rHuEpo) for larger groups of patients. In a 20% sample of all patients recorded to have been dialysed throughout 1987, statistically significant associations could be found by multifactorial analysis between haemoglobin (Hb) concentration and age, sex, primary renal disease, type of treatment, hours of dialysis per week, and number of years on renal replacement therapy. The type of dialyser membrane did not seem to play a role (although there was weak evidence of an effect of the dialyser). Mean Hb concentration for dialysis patients differed between countries as did the transfusion policy. In view of the high costs of the rHuEpo treatment and potential side-effects, factors such as method of dialysis and hours of haemodialysis per week should be taken into consideration in the treatment of anaemia in dialysis patient
Renal Transplantation in Diabetic Patients with or Without Simultaneous Pancreatic Transplantation 1986: Data from the EDTA Registry
This report summarises the outcome of 90 combined kidney/pancreatic grafts performed in Europe in 1986. Data for the combined kidney/pancreas grafts were obtained by a special questionnaire. The one-year patient and kidney graft survival is compared to the results of a group of 389 patients with diabetic nephropathy on the EDTA Registry data file who received kidney grafts alone. The recipients of combined kidney-pancreas grafts were younger, whereas a greater proportion of males received kidney graft alone. Patient survival at one year after transplantation was similar: 89% in recipients of combined transplants compared to 90% in recipients of kidney grafts alone. Kidney graft survival was 78% at one year for recipients of combined grafts versus 76%. It is concluded that pancreas transplantation has little effect on the fate of concomitant kidney grafts. The procedure should - in experienced hands and in selected patients - be almost as safe as kidney grafting alon
Rehabilitation of young adults during renal replacement therapy in Europe: 2. Schooling, employment, and social situation
The educational status, employment rate and social situation were studied in 617 patients between 21 and 35 years of age who started renal replacement therapy (RRT) as children. The data were derived from a special questionnaire concerning disability and rehabilitation sent to dialysis and transplant centres reporting to the EDTA Registry. Fifty-six percent of patients completed secondary school and one in three went on to vocational training. Eleven percent of patients attended university, and 16% were reported to have gone to a special school for the handicapped. Up to one-third of patients who attended different school types failed to complete their education. There were notable geographical differences in schooling and in employment. Fifty-six percent of all patients were employed. Lack of schooling was considered to be a major reason for unemployment. Sixty-one percent of patients with disabilities and 34% without disabilities were receiving invalidity payments. The place of residence of these patients aged 21-35 was usually the parental home. Compared to the general population of similar age, only a few patients were married (13.5% of the total study group) and 8% had children. In summary, the present report shows that the major factors influencing rehabilitation on RRT are the presence of disabilities, the method of treatment, geographical factors, duration of RRT, and the underlying primary renal diseas
Urinary proteome pattern in children with renal Fanconi syndrome
Background. The renal Fanconi syndrome (FS) is characterized by renal glucosuria, loss of electrolytes, bicarbonate and lactate, generalized hyperaminoaciduria and low-molecular-weight proteinuria. We studied the urinary low-molecular-weight proteome to identify excreted peptides indicative of a pathogenetic mechanism leading to tubular dysfunction. Methods. We established a urinary proteome pattern using capillary electrophoresis mass spectrometry (CE-MS) of 7 paediatric patients with cystinosis and 6 patients with ifosfamide-induced FS as the study group, and 54 healthy volunteers and 45 patients suffering from other renal diseases such as lupus nephritis (n = 8), focal segmental glomerulosclerosis (n = 27), minimal change disease (n = 7) and membranous glomerulonephritis (n = 3) as controls. Consequently, we conducted a blinded study consisting of 11 FS patients and 9 patients with renal disease other than FS. Additionally, we applied this pattern to 294 previously measured samples of patients with different renal diseases. Amino acid sequences of some marker proteins were obtained. Results. Specificity for detecting FS was 89% and sensitivity was 82%. The marker peptides constituting the proteome pattern are fragments derived from osteopontin, uromodulin and collagen alpha-1. Conclusions. CE-MS can be used to diagnose FS in paediatric patients and might be a future tool for the non-invasive diagnosis of FS. The reduced amount of the marker proteins osteopontin and uromodulin indicates loss of function of tubular excretion in all patients suffering from FS regardless of the underlying cause. In addition, the six different fragments of the collagen alpha-1 (I) chain were either elevated or reduced in the urine. This indicates a change of proteases in collagen degradation as observed in interstitial fibrosis. These changes were prominent irrespectively of the stages of FS. This indicates fibrosis as an early starting pathogenetic reason for the development of renal insufficiency in FS patient
EDTA Registry Centre Survey, 1986: Report from the European Dialysis and Transplant Association Registry
This paper summarises the information given on the 1986 EDTA Registry centre questionnaire which was returned by 82% of the 2,065 known dialysis and transplant centres in 33 European countries. Information is given on the number of patients alive on haemodialysis according to the type of dialysis facilities available where the patient was receiving dialysis and the number of patients receiving special types of dialysis. The centre questionnaire also included questions on testing for HIV infection, serological evidence or symptoms of AIDS and the diagnosis of hepatitis B in patients and staff. The data given in response to these questions are presented together with data on the involvement of dietitians and social workers in the treatment of patients with end stage renal failure. Finally, information on transplant activity in Europe and the treatment policies of transplanting centres is provide
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