Polymers Best Paper Award 2014

[No abstract available

Enhancing ordering dynamics in solvent-annealed block-copolymer films by lithographic hard masks supports

We studied solvent-driven ordering dynamics of block copolymer films supported by a densely cross-linked polymer network designed as organic hard mask (HM) for lithographic fabrications. The ordering of microphase separated domains at low degrees of swelling corresponding to intermediate/strong segregation regimes was found to proceed significantly faster in films on a HM layer as compared to similar block copolymer films on silicon wafers. The ten-fold enhancement of the chain mobility was evident in the dynamics of morphological phase transitions and of related process of terrace-formation on a macroscale, as well as in the degree of long-range lateral order of nanostructures. The effect is independent of the chemical structure and on the volume composition (cylinder-/ lamella-forming) of the block copolymers. In-situ ellipsometric measurements of the swelling behavior revealed a cumulative increase in 1-3 vol. % in solvent up-take by HM-block copolymer bilayer films, so that we suggest other than dilution effect reasons for the observed significant enhancement of the chain mobility in concentrated block copolymer solutions. Another beneficial effect of the HM-support is the suppression of the film dewetting which holds true even for low molecular weight homopolymer polystyrene films at high degrees of swelling. Apart from immediate technological impact in block copolymer-assisted nanolithography, our findings convey novel insight into effects of molecular architecture on polymer-solvent interactions.Comment: This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Macromolecules, copyright \c{opyright} American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/ma500561

Measuring rotational diffusion of colloidal spheres with confocal microscopy

We report an experimental method to measure the translational and rotational dynamics of colloidal spheres in three dimensions with confocal microscopy and show that the experimental values reasonably agree with the theoretical values. This method can be extended to study rotational dynamics in concentrated colloidal systems and complex bio-systems

Treatment of large uveal melanoma with transscleral resection: Comparing a combination with adjuvant ruthenium brachytherapy or neoadjuvant proton beam therapy

Einleitung: In einer retrospektiven monozentrischen Interventionsstudie soll die Behandlung großer uvealer Melanome im Hinblick auf ihr Lokalrezidiv- und Fernmetastasierungsrisiko ausgewertet werden. Zur Behandlung der Tumore erfolgte eine transsklerale Resektion in Kombination mit einer Bestrahlung, wobei es sich entweder um eine adjuvante Brachytherapie mit einem Ruthenium-Applikator oder eine neoadjuvante Protonentherapie handelte. Methoden: Insgesamt wurden 242 Patienten mit einem uvealen Melanom eingeschlossen. Einschlusskriterien waren eine Mindestprominenz des Tumors von 7,0 mm und ein größter basaler Tumordurchmesser von 23,0 mm. In der mittels adjuvanter Brachytherapie behandelten Gruppe waren 136 Patienten, während sich 106 Patienten in der neoadjuvanten Protonentherapie-Gruppe befanden. Zur besseren Vergleichbarkeit der Gruppen erfolgte eine Paarbildung anhand der folgenden Charakteristika: größter basaler Tumordurchmesser, Tumorprominenz und Tumorzelltyp. Der relative Einfluss einzelner Risikofaktoren auf das Lokalrezidiv- und Fernmetastasierungsrisiko wurde mit Hilfe eines multivariablen Cox-Regressionsmodells berechnet. Ferner wurden die Rate an Sekundärkomplikationen und der Visus über den Nachbeobachtungszeitraum untersucht. Ergebnisse: Nach drei und fünf Jahren wurden die Raten der Lokalrezidive und der Fernmetastasierung analysiert. Die Lokalrezidivraten betrugen 24,6% und 27,5% in der Ruthenium-Applikator-Gruppe, wohingegen diese in der Protonentherapie-Gruppe lediglich bei 4% und 9,1% lagen. Das angepasste Risiko eines Lokalrezidivs war in der Ruthenium-Applikator-Gruppe achtmal höher, nachdem Alter, Geschlecht, Tumorabstand zum Sehnervenkopf und Ziliarkörperinfiltration (p <0,001) berücksichtigt wurden. Die Metastasierungsraten betrugen 13,2% und 30,3% in der Ruthenium-Applikator-Gruppe sowie 23,2% und 31,8% in der Protonentherapie-Gruppe, ohne einen statistisch signifikanten Unterschied aufzuweisen. Ein Sekundärglaukom trat bei je einem Patienten in jeder Gruppe auf (1,4%). In der Ruthenium-Applikator-Gruppe mussten 11 Augen (15,7%) und in der Protonentherapie-Gruppe 6 Augen (8,5%) entfernt werden (p= 0,196). Diskussion und Fazit: Die transsklerale Resektion großer uvealer Melanome in Kombination mit einer neoadjuvanten Protonenbestrahlung führt im Vergleich zur adjuvanten Behandlung mit einem Ruthenium-Applikator zu einer geringeren lokalen Tumorrezidivrate. Es zeigte sich jedoch kein statistisch signifikanter Unterschied hinsichtlich der Fernmetastasierungsrate, der Raten an Sekundärkomplikationen, des Augenerhalts und des visuellen Outcomes am Ende des Untersuchungszeitraums.Introduction: In a retrospective single-center intervention study the treatment of large uveal melanomas was evaluated with regard to the risk of local recurrence and metastasis. To treat the tumors, a transscleral resection was performed in combination with two different types of radiation. Either adjuvant ruthenium brachytherapy or neoadjuvant proton therapy was applied. Methods: A total of 242 patients with uveal melanoma were included into the study. Inclusion criteria were a minimum tumor prominence of 7.0 mm and a largest basal tumor diameter of 23.0 mm. There were 136 patients in the group with adjuvant brachytherapy and 106 patients in the neoadjuvant proton therapy group. For better comparability between the groups, pairs were formed, based on largest basal tumor diameter, tumor height and tumor cell type. The relative influence of individual risk factors on the rate of local recurrence and metastasis was calculated using a multivariable Cox regression model. Furthermore, the rate of secondary complications and the visual acuity over the follow-up period were analyzed. Results: The rates of local tumor recurrence and metastasis were analyzed after three and five years. The local tumor recurrence rates were 24.6% and 27.5% in the brachytherapy group but only 4% and 9.1% in the proton beam therapy group. The adjusted risk of local tumor recurrence was eight times higher in the ruthenium applicator group after adjusting for the confounders age, sex, tumor distance to the optic nerve head and ciliary body infiltration (p < 0.001). The metastasis rates were 13.2% and 30.3% in the brachytherapy group and 23.2% and 31.8% in the proton beam therapy group, without a statistically significant difference. Secondary glaucoma occurred in one patient in each group (1.4%). 11 eyes (15.7%) in the ruthenium applicator group and 6 eyes (8.5%) in the proton beam therapy group had to be enucleated (p = 0.196). Discussion and conclusion: In large uveal melanoma excised by transscleral resection, a better local tumor control rate is achieved by combining the resection with a neoadjuvant proton beam therapy in comparison to an adjuvant brachytherapy with a ruthenium plaque. However, there was no statistically significant difference in metastasis rate, rates of secondary complications, eye preservation and the visual outcome at the end of the study period

Reorientation mechanisms of block copolymer/CdSe quantum dot composites under application of an electric field

Time- and temperature-resolved in situ birefringence measurements were applied to analyze the effect of nanoparticles on the electric field-induced alignment of a microphase separated solution of poly(styrene)-block-poly(isoprene) in toluene. Through the incorporation of isoprene-confined CdSe quantum dots the reorientation behavior is altered. Particle loading lowers the order–disorder transition temperature, and increases the defect density, favoring nucleation and growth as an alignment mechanism over rotation of grains. The temperature dependent alteration in the reorientation mechanism is analyzed via a combination of birefringence and synchrotron SAXS. The detailed understanding of the effect of nanoparticles on the reorientation mechanism is an important prerequisite for optimization of electric-field-induced alignment of block copolymer/nanoparticle composites where the block copolymer guides the nanoparticle self-assembly into anisotropic structures

Diagnostics of Damages in Reinforced Concrete by the Parameters of Electric Response to Mechanical Impact

A method for non-destructive testing of reinforced concrete based on thephenomenon of mechano-electric transformations is proposed in this work. The procedure forassessing damage in concrete is based on the measurement of an electric response to a weakelastic impact. It was found that the moments of crack formation and growth during bendingare accompanied by a significant decrease in the correlation coefficient of the electricresponses spectra and by a stepwise change in spectrum shift (at frequency domain) at whichthe maximum correlation coefficient is observed. It was determined that the increase of energyattenuation coefficient of the electric response can serve as a forerunner of a catastrophicdestruction in concrete. The diagnostic criteria proposed in this work can be used formonitoring the damage processes in reinforced concrete under bending conditions

Semi-classical treatment of proton-neutron monopole interaction

We apply a time dependent variational method to a many-body Hamiltonian consisting of a spherical shelf model term, a proton-proton and neutron-neutron pairing interaction and a monopole particle-hole and particle-particle proton-neutron interaction. The variational state is a generalized BCS state where all T = 1 Cooper pairs with T-z = 0, +/- 1 are included. Stationary solutions correspond to generalized BCS equations and define the static ground state. The linearized equations of motion are of RPA type and describe small oscillations of the nuclear system around the static ground state. Numerical application is made for a one level case. In contrast to previous treatments, the proton-neutron particle-particle interaction is included first in the mean field equations, defining the quasiparticle approximation, and then the residual interaction is taken into account by the RPA approach. In this way one obtains a noncollapsing RPA ground state.Peer reviewe

Impact of Adjuvant Ocular Interventions on the Quality of Life of Patients with Uveal Melanoma after Proton Beam Therapy

Introduction: Proton beam therapy is an established primary treatment for patients with nonmetastasized uveal melanoma. Adjuvant local interventions, like intravitreal injections or surgery, were shown to improve long-term eye preservation; however, their impact on the patient's quality of life (QOL) remains unknown. Methods: In a post-radiotherapeutic follow-up, we prospectively collected data on QOL, visual acuity, and interventional adjuvant procedures. QOL was measured with QOL-C30 questionnaire and quality of life questionnaire OPT30 at baseline, and at 3 and 12 months after proton therapy. Patients were grouped by the type of adjuvant treatment. The impact on QOL was analyzed by comparing changes in the mean score values and visual acuity for different interventional subgroups, with generalized linear mixed models and Wilcoxon signed-rank tests. Results: We received 108 (100%) and 95 (88.0%) questionnaires at 3 and 12 months post-therapy, respectively. Adjuvant interventions included observation (n = 61, 56.5%), intravitreal injections (n = 17, 15.7%), and an intraocular surgical procedure (n = 30, 27.8%). In the latter group, several QOL items significantly declined after the 3-month adjuvant interval, but they partially recovered at the 12-month follow-up. In all adjuvant-intervention groups, global QOL scores returned to baseline levels at 12 months. Conclusion: Posttreatment adjuvant interventions had no long-lasting effects on QOL in patients with uveal melanoma