Quantum thermal bath for molecular dynamics simulation

International audienceMolecular dynamics (MD) is a numerical simulation technique based on classical mechanics. It has been taken for granted that its use is limited to a large temperature regime where classical statistics is valid. To overcome this limitation, the authors introduce in a universal way a quantum thermal bath that accounts for quantum statistics while using standard MD. The efficiency of the new technique is illustrated by reproducing several experimental data at low temperatures in a regime where quantum statistical effects cannot be neglected

Radiative heat transfer from a black body to dielectric nanoparticles

International audienceHeating of dielectric nanoparticles by black-body radiation is investigated by using molecular-dynamics simulation. The thermal interaction with the radiation is modeled by coupling the ions with a random electric field and including a radiation reaction force. This approach shows that the heat is absorbed by the polariton mode. Its subsequent redistribution among other vibration modes strongly depends on the particle size and on temperature.We observe energy trapping in a finite subset of vibrational mode

No evidence of association between NOD2/CARD15 gene polymorphism and atherosclerotic events after renal transplantation.

International audienceStable renal transplant recipients (RTR) display high rates of atherosclerotic events (AE). Innate immunity and especially vascular inflammation play a role in the pathogenesis of atherosclerosis. It is illustrated both by an increased occurrence of postrenal transplant cardiovascular events in patients with elevated levels of C-reactive protein and by a correlation between posttransplant AE and Toll-like receptor-4 Asp299Gly polymorphism. Here, we analyze the influence NOD2/CARD15 gene polymorphism since NOD2 can modulate macrophage pro-inflammatory activity and macrophage is present in early atherosclerotic lesions. The incidence of single nucleotide polymorphism (SNP) in the three major polymorphic region of NOD2 gene (SNP8, SNP12 and SNP13) was assessed in 182 RTR and the correlation between such polymorphism and the development of AE was analyzed. No correlation was observed between NOD2 gene polymorphism and the occurrence of AE after renal transplantation. NOD2 gene polymorphism thus does not appear to influence cardiovascular complications in RTR

The Interleukin-6 Gene Promoter Polymorphism -174 and Atherosclerotic Events in Overweight Transplanted Patients

Chronic inflammation plays a pivotal role in atherosclerosis. We hypothesized that combining overweight and a greater genetic capacity to produce IL-6 predicted by IL-6 gene promoter polymorphism at position -174 (G→C) may allow to identify individuals exhibiting higher IL-6 and C-reactive protein (CRP) concentrations with a higher risk of atherosclerotic events (AE). The occurrence of AE was analyzed with respect to body mass index, IL-6 gene promoter polymorphism at position -174 (G→C), and other relevant risk factors, retrospectively, in 217 renal transplant recipients and, prospectively, in 132. Circulating IL-6 concentrations were closely related to BMI (r = 0.55, P = .0005). In overweight patients, serum IL-6 concentration was found to be significantly lower in C carriers than in GG patients (4.2 [1.0–5.1] versus 7.3 pg/mL [4.4–100]; P = .025). The incidence of AE was higher in overweight GG patients (29.5% versus 10.1%; P = .0003). In multivariate analysis, overweight-GG had an increased risk to develop AE (HR 2.96 [95% CI 1.09–8.04], P = .034 in the retrospective cohort, and HR 2.99 [95% CI 0.92–9.33], P = .069 in the prospective cohort). All these data are consistent with a role for both genetic and environmental determinants of inflammation (white adipose tissue mass) in the development of AE in renal transplanted patients

Comment on “Quantum thermal bath for molecular dynamics simulation” reply

International audienceA Reply to the Comment by Alexandre H. Barrozo and Maurice de Koning

[Urologic cancer in patients with kidney transplantation]

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[Urologic cancer in patients with kidney transplantation]

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Impact of malnutrition-inflammation on the association between homocysteine and mortality.

International audienceWhether high total serum homocysteine levels (tHcy) contribute to increase mortality or offer a survival advantage in chronic hemodialysis patients remains controversial. We conducted a prospective study to determine the impact of tHcy on survival in this population with special respect to chronic inflammation-malnutrition state (CIMS). In this prospective study, 459 hemodialysis patients from 10 dialysis centers located in two regions of France were included. A number of baseline parameters were measured including tHcy and markers of CIMS. Over a mean follow-up period of 54 months, 219 deaths (47.7%) occurred, of which 114 (52%) were of cardiovascular (CV) origin. tHcy of equal to or greater than 30 micromol/l was associated with a higher risk of all-cause mortality in patients without CIMS (hazard ratio (HR): 1.55 (confidence interval (CI): 1.12-4.72)), but not in overall dialysis population or those with CIMS. When only CV mortality was considered, tHcy of equal to or greater than 30 micromol/l was associated with a higher risk in patients without (CIMS HR: 1.91 (CI: 1.23-3.23)), but not in those with CIMS. Hyperhomocysteinemia is a strong risk factor for all-cause and CV mortality in hemodialysis patients who do not present CIMS. This association might be masked in patients with CIMS

Rheumatoid purpura associated with toxocariasis

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