Accurate interaction energies at DFT level by means of an efficient dispersion correction

This paper presents an approach for obtaining accurate interaction energies at the DFT level for systems where dispersion interactions are important. This approach combines Becke and Johnson's [J. Chem. Phys. 127, 154108 (2007)] method for the evaluation of dispersion energy corrections and a Hirshfeld method for partitioning of molecular polarizability tensors into atomic contributions. Due to the availability of atomic polarizability tensors, the method is extended to incorporate anisotropic contributions, which prove to be important for complexes of lower symmetry. The method is validated for a set of eighteen complexes, for which interaction energies were obtained with the B3LYP, PBE and TPSS functionals combined with the aug-cc-pVTZ basis set and compared with the values obtained at CCSD(T) level extrapolated to a complete basis set limit. It is shown that very good quality interaction energies can be obtained by the proposed method for each of the examined functionals, the overall performance of the TPSS functional being the best, which with a slope of 1.00 in the linear regression equation and a constant term of only 0.1 kcal/mol allows to obtain accurate interaction energies without any need of a damping function for complexes close to their exact equilibrium geometry

Physical health and the onset and persistence of depression in older adults: an eight-wave prospective community based study.

Background. Poor physical health has long been recognized to be one of the most important risk factors for depression in older adults. Since many aspects of physical health can be targeted for improvement in primary care, it is important to know whether physical health problems predict the onset and/or the persistence of depression. Methods. The study is based on a sample which at the outset consisted of 327 depressed and 325 non-depressed older adults (55-85) drawn from a larger random community-based sample in the Netherlands. Depression was measured using the Center for Epidemiologic Studies Depression scale (CES-D) at eight successive waves. Results. From all incident episodes, the majority (57%) was short-lived. These short episodes could generally not be predicted by physical health problems. The remaining incident episodes (43%) were not short-lived and could be predicted by poor physical health. Chronicity (34%) was also predicted by physical health problems. Conclusions. The study design with its frequent measurements recognized more incident cases than previous studies; these cases however did have a better prognosis than is often assumed. The prognosis of prevalent cases was rather poor. Physical health problems were demonstrated to be a predictor of both the onset and the persistence of depression. This may well have implications for prevention and intervention

On the applicability of local softness and hardness

9 pages, 5 figures, 3 schemes, 2 tables.-- PMID: 20094672 [PubMed].Global hardness and softness and the associated hard/soft acid/base (HSAB) principle have been used to explain many experimental observed reactivity patterns and these concepts can be found in textbooks of general, inorganic, and organic chemistry. In addition, local versions of these reactivity indices and principles have been defined to describe the regioselectivity of systems. In a very recent article (Chem.–Eur. J. 2008, 14, 8652), the present authors have shown that the picture of these well-known descriptors is incomplete and that the understanding of these reactivity indices must be reinterpreted. In fact, the local softness and hardness contain the same potential information and they should be interpreted as the local abundance or concentration of their corresponding global properties. In this contribution, we analyze the implications of this new point of view for the applicability of these well-known descriptors when comparing two sites in three situations: two sites within one molecule, two sites in two different, but noninteracting molecules, and two sites in two different, but interacting, molecules. The implications on the HSAB principle are highlighted, leading to the discussion of the role of the electrostatic interaction.M. T. thanks the European Community for financial help through the postdoctoral grant MEIF-CT-2006-025362. P. G. and F. D. P are indebted to the Fund for Scientific Research—Flanders (FWO) and to the Free University of Brussels for continuous support to their group. P. W. A. thanks NSERC, the Canada Research Chairs, and Sharcnet for research support.Peer reviewe

Depressive symptoms and risk of Alzheimer's disease in more highly educated older people

In an earlier study we observed that a depressive syndrome was highly predictive of developing Alzheimer's disease (AD) in older persons with normal baseline cognition and higher levels of education. We interpreted these findings as the depression being an early noncognitive manifestation of AD in persons with more cognitive reserve. The present study examines whether specific symptoms of depression can be identified that predict AD among older subjects with higher levels of education. In the community-based Amsterdam Study of the Elderly (AMSTEL), a sample of 3,147 nondemented persons with normal cognition, 65 to 84 years old, was selected and divided into subjects with >8 years and 8 years and 31 with 8 years of education depressed mood and subjective bradyphrenia were strongly associated with incident AD. No association between depressive symptoms and AD was observed among subjects with <or =8 years of education. Both depressed mood and subjective bradyphrenia seem to indicate subclinical AD in older people with higher levels of education. Clinicians should be alert that in these persons, AD may become apparent within a relatively short period of tim

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

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

Demography of Dialysis and Transplantation in Children in Europe, 1985: Report from the European Dialysis and Transplant Association Registry

At the end of 1985 there were 5482 patients known to the Registry who started renal replacement therapy (RRT) between the ages of 6 months and 15 years. Of these, approximately 25% had died, 30% were still aged less than 15 years, and the other 45% were older. The acceptance rate of new patients over the last 10 years has slowly but steadily increased; six new paediatric patients per million child population probably represents the likely needs of the near future. Hospital haemodialysis remained the main form of renal replacement therapy in new patients, while 3 years after start of RRT, transplantation became the most frequently used replacement therapy; CAPD appeared to be used mainly in children with a short waiting time for transplantation. Out of the 384 grafts reported in 1985, only 16% were from living related donors; among 321 cadaver grafts, 24% were second and only 3% were third grafts. Glomerulonephritis and pyelonephritis accounted for 50% of all primary renal diseases. During the last 5 years, the proportion with glomerulonephritis seems to have decreased slightly. Hyperkalaemia and fluid overload have still to be considered the main causes of death. Only in 17% of all cases was the cause of death reported as unknown or undetermine

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