Search results for " Polymers"

Coarse Graining of Short Polythylene Chains for Studying Polymer Crystallization.

2015

We derive coarse-grained models of polyethylene in the melt state with the aim to study polymer crystallization. This requires a low level of coarse-graining:  We use a mapping of two CH2 groups onto one bead. The coarse-grained beads are connected with harmonic springs, an optimized angular potential, and an optional torsional potential. Coarse-grained potentials are derived from detailed all-atom simulations, and an optimized form of the force field is then derived which achieves a good accuracy in reproducing the static properties of the chains. We address the question over which temperature range such models can be used, and in particular if the model is capable of reproducing the phase…

Simulation of Phase Transitions of Single Polymer Chains: Recent Advances

2006

The behaviour of a flexible polymer chain in solvents of variable quality in dilute solution is discussed both in the bulk and in the presence of an adsorbing wall. Monte Carlo simulations of coarse-grained bead-spring models and of the bond fluctuation model are presented and interpreted in terms of phenomenological theories and scaling concepts. Particular attention is paid to the behaviour of the polymer chain when the temperature of the polymer solution gets lower than the Theta temperature. It is argued that the adsorption transition line at the Theta temperature splits into lines of wetting and drying transitions of polymer globules attached to the wall. In addition, it is shown that …

Supramolecular hierarchy among halogen and hydrogen bond donors in light-induced surface patterning

2015

Halogen bonding, a noncovalent interaction possessing several unique features compared to the more familiar hydrogen bonding, is emerging as a powerful tool in functional materials design. Herein, we unambiguously show that one of these characteristic features, namely high directionality, renders halogen bonding the interaction of choice when developing azobenzene-containing supramolecular polymers for light-induced surface patterning. The study is conducted by using an extensive library of azobenzene molecules that differ only in terms of the bond-donor unit. We introduce a new tetrafluorophenol-containing azobenzene photoswitch capable of forming strong hydrogen bonds, and show that an io…

Studying the User Experience in Online Banking Services: An Eye-Tracking Application

2019

Abstract Neuromarketing as research method contrbutes to understanding consumer behavior a step further than traditional marketing research. The aim of the current study is to explore the usability and cognitive understanding of banking services webpages. In this regard, the theoretical part of the article reviews the relevant literature related to neuromarketing as research method and the use of eye-tracker as research technique. Further on, a two-step research design was developed for studying the consumers’ attention and memory during and after viewing two Romanian banking services websites. The results showed that the way information is structured and presented on the webpages influence…

Measurements of alveolar pO2 using 19F-MRI in partial liquid ventilation.

2003

Rationale and Objectives: Partial liquid ventilation using Perfluorcarbon (PFC) is an innovative treatment of acute respiratory distress syndrome. However, the underlying mechanisms are not totally clear. The aim was to investigate the distribution of oxygen partial pressure within the PFC-filled lung (ppO 2 ). Methods: Nine pigs underwent partial liquid ventilation, receiving 20 mL PFC/kg bodyweight (bw). Measurements were obtained by a chemical shift selective TurboFLASH sequence at different axial lung levels. ppO 2 was calculated from 1 9 F-MRI by nonlinear curve T 1 -fitting technique after noise correction. Results: Quantification and distribution of ppO 2 was performed successfully. …

1987

Polyamides et polyesters a base d'acide di-n-alcoxy-2,5 terephtalique et d'hydroquinone avec des chaines laterales longues (n>8) formant une mesophase

Organoboron Polymers for Photovoltaic Bulk Heterojunctions

2010

Silk fibroin scaffolds enhance cell commitment of adult rat cardiac progenitor cells.

2015

The use of three-dimensional (3D) cultures may induce cardiac progenitor cells to synthesize their own extracellular matrix (ECM) and sarcomeric proteins to initiate cardiac differentiation. 3D cultures grown on synthetic scaffolds may favour the implantation and survival of stem cells for cell therapy when pharmacological therapies are not efficient in curing cardiovascular diseases and when organ transplantation remains the only treatment able to rescue the patient’s life. Silk fibroin-based scaffolds may be used to increase cell affinity to biomaterials and may be chemically modified to improve cell adhesion. In the present study, porous, partially orientated and electrospun nanometric n…

POROUS SCAFFOLDS BASED ON PLLA/FUNCTIONALISED POLYMERS BLENDS PRODUCED BY THERMALLY INDUCED PHASE SEPARATION

2014

Polylactide-based materials science strategies to improve tissue-material interface without the use of growth factors or other biological molecules

2018

In a large number of medical devices, a key feature of a biomaterial is the ability to successfully bond to living tissues by means of engineered mechanisms such as the enhancement of biomineralization on a bone tissue engineering scaffold or the mimicking of the natural structure of the extracellular matrix (ECM). This ability is commonly referred to as "bioactivity". Materials sciences started to grow interest in it since the development of bioactive glasses by Larry Hench five decades ago. As the main goal in applications of biomedical devices and tissue scaffolds is to obtain a seamless tissue-material interface, achieving optimal bioactivity is essential for the success of most biomate…