The simulated glass transition temperature (Tg) is usually determined by the dilatometry procedure. However, we recently showed that a greater glass transition domain is uncovered where specific ...volume, coefficient of thermal expansion and heat capacity vary. This domain extends over 150 K, definitively higher than the experimental 3–5 K, raising the question of the identification of Tg. This article thus presents the computation of the bulk modulus and the Grüneisen parameter of two polymers, polyethylene and polystyrene. Fit of the Murnaghan equation when the system is in mechanical equilibrium, and the volume fluctuation method are used. The first method leads to important standard deviation for values higher than Tg. With the latter procedure, the computing values data are found consistent with experimental data for temperatures higher and lower than the glass transition domain. This study confirms the enlargement of the glass transition domain, and the difficulty to associate Tg with a specific change in the molecular behavior.
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•We confirm that molecular dynamics simulation leads to a glass transition domain spread over 150 K.•The bulk modulus computed using a dynamics approach agrees very well with experimental data.•We show that bulk modulus computed at the mechanical equilibrium is relatively steady until the glass transition domain.•The bulk modulus of polymers is in order of 2 GPa if no glass transition would occur.•The temperature behavior of the Grüneisen parameter extracted from simulation agrees with experimental data.
Protecting from solar radiation remains a very stimulating field of research and development. Improvement of performances of UV/IR radiation shielding devices is thus constantly pursued. With ...increase of computer strength and code efficiency, simulation becomes a real asset in this investigation. In this study, we report an efficient multiscale simulation protocol to design and optimize such photonic devices based on polymers. The simulation approach combines atomistic-level techniques, i.e. classical molecular mechanics, and linear scaling-DFT in order to get full description of the optical properties of polymers over a large wavelength range. At each step of the procedure, validation with experimental data is carried out, confirming the accuracy of the approach. The resulting optical constants enable designing of a multilayer photonic heterostructure purposely optimized for UV/NIR-radiations protection. The ensuing simulated device reveals very promising optical performance. It exhibits a transparency higher than 90% in the visible range and shows high UV absorptance. Moreover, a strong NIR-shielding ability of 96% is achieved.
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•A protocol to design and optimize polymers-based photonic devices is proposed.•The approach combines atomistic-level techniques and device-level simulation.•The ensuing simulated device reveals very promising optical performance.•Transparency higher than 90% and high UV absorptance are achieved.•A strong NIR-shielding ability of 96% is obtained.
Aims:
To assess the impact of the molecular subtype (MS) on the total number of CK19 mRNA copies in all positive SLN (TTL) threshold, to predict non-SLN affectation, and to compare 5 years ...progression-free survival (PFS) according to the risk of recurrence (ROR) group by PAM50.
Methods:
Cohort with infiltrating breast cancer with intra-operative metastatic SLN detected by one-step nucleic acid amplification (OSNA) assay who underwent subsequent ALND. Logistic regression was used to assess a possible interaction between TTL and MS(Triple Negative, Her-2-Enriched, Luminal A, or Luminal B), or hormone receptors (HR: positive or negative) by immunohistochemistry (IMH). Cox regression was used to compare PFS and OS in the 3 ROR groups (high, medium, or low).
Results:
TTL was predictive of non-SLN affectation in both univariate (OR 95% CI: 1.72 1.43, 2.05, P < .001) and multivariate (1.55 95% CI: 1.04, 2.32, P = .030) models, but MS-IMH or HR-IMH, and their interactions with TTL were not (best multivariate model: HR + main effect OR 1.16 95% CI: 0.18, 7.64, P = .874; interaction OR: 1.04 0.7, 1.55, P = .835; univariate model: HR + main effect OR: 1.44 95% CI: 0.85, 2.44, P = .180). PFS was lower in the high-risk ROR group (81.1%) than in the low-risk group (93.9%) (HR: 3.68 95 CI: 1.70, 7.94, P < .001).
Conclusions:
our results do not provide evidence to support the utilization of subtype-specific thresholds for TTL values to make therapeutic decisions on the axilla. The ROR group was predictive of 5 years-PFS.
An extensive understanding in the molecular motions that occur in Nafion® should lead to important development of improved proton exchange membrane for use in fuel cells (PEMFC). As water molecules ...are added in the system, changes within the Nafion® chain definitely take place. To visualize such a process, molecular dynamics is especially useful. Can information gained at this level of details be useful to propose new molecules, with ultimately better physical properties, such as higher proton conductivity? For this purpose, we first computed non‐bond parameters stemming from the study of the trifluorosufonic acid. They are inserted in the pcff force field. We then applied the procedure developed in our lab to extract the glass transition temperature of Nafion® with different water uptakes. The plasticization effect is first confirmed, fostering a molecular analysis. The particular behavior of the sulfur‐sulfur distance is revealed, guiding the design of new monomers.
The incidence of prosthesis infections after breast reconstruction is of the order of 4% to 13% according to the literature. In surgical patients, Staphylococcus aureus (S. aureus) is the bacterial ...species most often responsible for surgical site infections. In cardiac surgery, screening for carriage of S. aureus and preoperative decontamination are carried out routinely before prosthetic surgery. We retrospectively reviewed data from patients at our institution between January 2011 and December 2013. Our series showed that the prosthesis infection rates were in the range of 5.92% in 2008 with an ISO rate of S. aureus 3.61%. Routine screening for prosthetic reconstructions was performed to assess the impact of preoperative decontamination patients in carriers of S. aureus. This screening was done in 381 patients: 17.8% of patients were carriers of S. aureus ; 11 patients have an ISO (or an incidence rate of 2.88%) ; 5 patients have an ISO S. aureus (an incidence of S. aureus ISO 1.3%). The introduction of the screening process, allowed a drop of 5.92% ISO rate at 1.46% with a passage of S. aureus SSI rates of 3, 60% to 0.72%. In the near future, studies are needed to confirm these encouraging results, to demonstrate the efficacy of preoperative decontamination in carriers of S. aureus patients before laying prosthesis.
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