705 research outputs found

    Osmotic Pressure of Solutions Containing Flexible Polymers Subject to an Annealed Molecular Weight Distribution

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    The osmotic pressure PP in equilibrium polymers (EP) in good solvent is investigated by means of a three dimensional off-lattice Monte Carlo simulation. Our results compare well with real space renormalisation group theory and the osmotic compressibility K \propto \phi \upd \phi/\upd P from recent light scattering study of systems of long worm-like micelles. We confirm the scaling predictions for EP based on traditional physics of quenched monodisperse polymers in the dilute and semidilute limit. Specifically, we find Pϕ2.3P\propto \phi^{2.3} and, hence, Kϕ0.3K \propto \phi^{-0.3} in the semidilute regime --- in agreement with both theory and experiment. At higher concentrations where the semidilute blobs become too small and hard-core interactions and packing effects become dominant, a much stronger increase % \log(P/\phi)\approx \log(\Nav^2/\phi) \propto \phi is evidenced and, consequently, the compressibility decreases much more rapidly with ϕ\phi than predicted from semidilute polymer theory, but again in agreement with experiment.Comment: 7 pages, 4 figures, LATE

    Entropy of water and the temperature-induced stiffening of amyloid networks

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    In water, networks of semi-flexible fibrils of the protein α\alpha-synuclein stiffen significantly with increasing temperature. We make plausible that this reversible stiffening is a result of hydrophobic contacts between the fibrils that become more prominent with increasing temperature. The good agreement of our experimentally observed temperature dependence of the storage modulus of the network with a scaling theory linking network elasticity with reversible crosslinking enables us to quantify the endothermic binding enthalpy and an estimate the effective size of hydrophobic patches on the fibril surface.Comment: 13 pages, 6 figure

    End-fire versus side-fire:a randomized controlled study of transrectal ultrasound guided biopsies for prostate cancer detection

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    Objectives: To compare prostate cancer detection rates between end-fire and side-fire ultrasound guided prostate biopsy techniques. Methods: A prospective randomized controlled trial was performed in patients who underwent prostate biopsy between 2009 and 2014. Patients were randomly assigned to the end-fire or side fire biopsy groups and underwent transrectal ultrasound guided prostate biopsy. The overall prostate cancer detection rate was compared between the two probe configurations. Trial was registered at Clinical Trials.gov with identifier: NCT00851292. Results: A total of 730 patients were included and randomized, 371 patients underwent prostate biopsy with side-fire probe and 359 patients with the end-fire probe. Prostate cancer detection rates were 52.4% in the end fire group and 45.6% in the side fire group (p = .066). Conclusions: No significant difference was found in detection rate of prostate cancer between the end-fire and side-fire probe in transrectal ultrasound guided prostate biopsy, neither for detection rate of prostate cancer in the apex

    Computational confirmation of scaling predictions for equilibrium polymers

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    We report the results of extensive Dynamic Monte Carlo simulations of systems of self-assembled Equilibrium Polymers without rings in good solvent. Confirming recent theoretical predictions, the mean-chain length is found to scale as \Lav = \Lstar (\phi/\phistar)^\alpha \propto \phi^\alpha \exp(\delta E) with exponents αd=δd=1/(1+γ)0.46\alpha_d=\delta_d=1/(1+\gamma) \approx 0.46 and αs=[1+(γ1)/(νd1)]/20.60,δs=1/2\alpha_s = [1+(\gamma-1)/(\nu d -1)]/2 \approx 0.60, \delta_s=1/2 in the dilute and semi-dilute limits respectively. The average size of the micelles, as measured by the end-to-end distance and the radius of gyration, follows a very similar crossover scaling to that of conventional quenched polymer chains. In the semi-dilute regime, the chain size distribution is found to be exponential, crossing over to a Schultz-Zimm type distribution in the dilute limit. The very large size of our simulations (which involve mean chain lengths up to 5000, even at high polymer densities) allows also an accurate determination of the self-avoiding walk susceptibility exponent γ=1.165±0.01\gamma = 1.165 \pm 0.01.Comment: 6 pages, 4 figures, LATE

    Offline and online scheduling of electric vehicle charging with a minimum charging threshold

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    The increasing penetration of electric vehicles (EVs) requires the development of smart charging strategies that accommodate the increasing load of these EVs on the distribution grid. Many existing charging strategies assume that an EV is allowed to charge at any rate up to a given maximum rate. However, in practice, charging at low rates is inefficient and often even impossible. Therefore, this paper presents an efficient algorithm for scheduling an EV within a decentralized energy management system that allows only charging above a given threshold. We show that the resulting optimal EV schedule is characterized by an activation level and a fill-level. Moreover, based on this result, we derive an online approach that does not require predictions of uncontrollable loads as input, but merely a prediction of these two characterizing values. Simulation results show that the online algorithm is robust against prediction errors in these values and can produce near-optimal online solutions

    Формування стратегії фінансування зобов’язань при здійсненні комерційними банками інвестиційної діяльності

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    Проведено аналіз мікро- і макроекономічних аспектів інвестиційної діяльності комерційних банків. Досліджені проблеми формування ефективної інвестиційної політики банків. У статті наведена постановка задачі узгодження фінансових потоків при різних обмеженнях

    Формування теоретичної моделі геополітичного дискурсу у вітчизняній політичній думці кінця ХХ – початку ХХІ століття

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    У статті висвітлюються питання щодо започаткування новітньої дослідницької традиції геополітичного дискурсу у проблематиці вітчизняної політичної думки ХХ – початку ХХІ століття. Зазначено позиції провідних вітчизняних вчених щодо формування емпіричного та ідейно-теоретичного підґрунтя для утвердження цієї традиції політичного дослідження.The article considers the questions of the becoming of a new research tradition of geopolitical discourse in the topic of native political thought of the 20-th – the beginning of the 21-st century. The views of leading home scientists about the development of empirical, ideological and theoretical basis for the maintenance of this tradition of political research are pointed out

    High-dose carboplatin, thiotepa and cyclophosphamide (CTC) with peripheral blood stem cell support in the adjuvant therapy of high-risk breast cancer: a practical approach.

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    In 29 chemotherapy-naive patients with stage II-III breast cancer, peripheral blood stem cells (PBSCs) were mobilised following fluorouracil 500 mg m-2, epirubicin 90-120 mg m-2 and cyclophosphamide 500 mg m-2 (FEC) and granulocyte colony-stimulating factor (G-CSF; Filgrastim) 300 microgram s.c. daily. In all but one patient, mobilisation was successful, requiring three or fewer leucocytopheresis sessions in 26 patients; 28 patients subsequently underwent high-dose chemotherapy consisting of carboplatin 1600 mg m-2, thiotepa 480 mg m-2 and cyclophosphamide 6 g m-2 (CTC) followed by PBSC transplantation. Haemopoietic engraftment was rapid with a median time to neutrophils of 500 x 10(6) l(-1) of 9 days (range 8-10) in patients who received G-CSF after PBSC-transplantation; platelet transfusion independence was reached within a median of 10 days (range 7-16). Neutropenic fever occurred in 96% of patients. Gastrointestinal toxicity was substantial but reversible. Renal, neural or ototoxicity was not observed. Complications related to the central venous catheter were encountered in 64% of patients, with major vein thrombosis occurring in 18%. High-dose CTC-chemotherapy with PBSC-transplantation, harvested after mobilisation with FEC and G-CSF, is reasonably well tolerated without life-threatening toxicity and is a suitable high-dose strategy for the adjuvant treatment of breast cancer
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