arXiv subjects

Jorge Monreal

Publications and source records attributed to Jorge Monreal.

4 recordsLinked to original sources

arXiv2016

Polyelectrolyte Polypeptide Scaling Laws Via Mechanical and Dielectric Relaxation Measurements

Experimental results from mechanical viscoelastic as well as dielectric relaxation times were compared to theoretical expectations utilizing polymer scaling theory. Viscoelastic relaxation of a hydrogel at 33% relative humidity fabricated from co-poly-L-(glutamic acid$_{4}$, tyrosine$_{1}$) [PLEY(4:1)] crosslinked with poly-L-lysine scaled with concentration according to reptation dynamics. High frequency dielectric relaxation of aqueous copolymer PLEY(4:1) scaled with concentration as an ideal chain and aqueous Poly-L-glutamic acid scaled as an extended chain. The study shows that two seemingly different measurement methods can yield information about the state of polymer chain conformation in situ.

cond-mat.soft↗

arXiv2016

Nonlinearity In A Crosslinked Polyelectric Polypeptide

Youngs modulus of soft solids composed of crosslinked synthetic polypeptides has been determined under different conditions. Co-poly-(L-glutamic acid$_4$, L-tyrosine$_1$) [PLEY (4:1)] was crosslinked with poly-L-lysine (PLK) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Elasticity was assessed by subjecting samples to a compressive strain. Cross-linked material at high relative humidity, RH 75-85%, exhibited non-linear elasticity. Stress-strain response was approximately linear at low strain but nonlinear above a threshold strain. Analysis of the secant modulus revealed apparent softening of samples at low strain and hardening at high strain, as in biological soft tissues. Fitting stress-strain data with a neo-Hookean model yielded approximately 40 $\le E \le$ 300 kPa at high RH. Viscoelasticity was nonlinear at low RH. The average viscosity-driven relaxation time was 13 min at high strain and 6 min at low strain. Analysis of the derivative of the secant modulus for non-linear elastic materials revealed a transient response up to a strain of $\varepsilon \approx$ 0.18-0.20. Above this range, oscillations tended to zero. Non-linear viscoelastic materials showed lower-amplitude oscillations than samples at high RH up to $\varepsilon \approx$ 0.06 and strong damping thereafter. The data suggest that it will be possible to engineer mechanical properties of polypeptide materials.

cond-mat.soft↗

arXiv2016

Spheroidal and Nanocrystal Structures From Carbodiimide Crosslinking Reaction With RADA16

RADA16 is a widely studied polypeptide known for its ability to self-assemble into $\beta$-sheets that form nanofibers. Here we show that it is possible to self-crosslink the molecule via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) as aqueous solutions. The product results in a mix of nanocrystals and near micron-size spherules. SEM and TEM pictures provide a view of the structures and nano tracking analysis give their size distributions. FTIR analysis provides evidence for the existence of a crosslinking reaction.

cond-mat.soft↗

arXiv2014

General Navier-Stokes-like Momentum and Mass-Energy Equations

A new system of general Navier-Stokes-like equations is proposed to model electromagnetic analogous to hydrodynamic. While most attempts to derive analogues of hydrodynamic to electromagnetic, and vice-versa, start with Navier-Stokes or a Euler approximation, we propose general conservation equations as a starting point. Such equations provide a structured framework from which additional insights into the problem at hand could be obtained. To that end, we propose a system of momentum and mass-energy conservation equations coupled through both momentum density and velocity vectors.

physics.class-ph↗