Significant benefits of new communication technology for time delay management in STEMI patients.

BACKGROUND: In the acute phase of STEMI, the length of the total ischemic interval is the principal factor affecting both short- and long-term mortality. The length of the interval remains a global problem, and in EU countries these figures vary between 160 and 325 min. METHODS AND RESULTS: The aim of our research was to assess the benefit of the systematic implementation of the new smartphone-based communication technology "STEMI" enabling immediate ECG picture and voice consultation between an EMS crew in the field and a cardiologist in the PCI-center. The transfer of ECG was associated with 92% technical success. 5 Monthly data from 2016 were compared from the reference2 monthly data set in 2015 when the data in the same area was collected in the SLOVAKS registry. The 5-months data from 2016 were compared to the reference group from 2015, when similar 2-months data in the same area in SLOVAKS registry was collected but communication technology "STEMI" technology was not used. In the monitored period in 2016 we recorded a significant decrease in unwanted secondary STEMI transportations (34.32% vs. 12.9%, p<0.001) and a significant reduction in the total ischemic interval (241 min vs. 181 min, p = 0.03). There was no significant decrease in the subinterval of "admission-pPCI" (28min vs. 23 min, p = 0.144). CONCLUSION: The systematic use of smartphone-based communication technology "STEMI" enabling remote ECG picture consultation between an EMS crew and a cardiologist in PCI-center had a positive impact on the quality of care for patients with acute STEMI and brought clinical practice closer to the current ESC Guidelines. It significantly decreased the ratio of unwanted secondary transportations and led to a significant reduction in the total ischemic interval.

Effect of chemical structure on the volume-phase transition in neutral and weakly charged poly(N-alkyl(meth)acrylamide) hydrogels studied by ultrasmall-angle x-ray scattering.

Neutral poly(N-isopropylacrylamide) (PIPAAm), poly(N,N-diethylacrylamide) (PDEAAm), and poly(N-isopropylmethacrylamide) (PIPMAm) hydrogels and their weakly charged counterparts prepared by copolymerizing with sodium methacrylate (x(MNa)=0,0.025,0.05) were studied using ultrasmall-angle x-ray scattering. The volume-phase transition in hydrogels was observed as an increase in the inhomogeneity correlation length of the networks. The change in inhomogeneity correlation length was abrupt in neutral PIPAAm and PIPMAm gels with increase in temperature but was continuous in neutral PDEAAm gels. Addition of ionic comonomer to the network backbone suppressed the volume-phase transition in poly(N-alkylacrylamide)s but not in PIPMAm. The observed differences in temperature-induced volume change of these three polymers in water cannot be rationalized based on their relative hydrophobicity and are instead explained by considering the hydrogen-bonding constraints on their thermal fluctuations. Both PIPAAm and PDEAAm undergo volume collapse since their thermal fluctuations are constrained by hydrogen bonding with water to an extent that beyond a critical temperature they seek entropic compensation. Although thermal fluctuations in both PIPAAm and PIPMAm are equally constrained, thermal energy of the latter can be relaxed via the rotation of alpha-methyl groups allowing it greater flexibility. Compared to N-alkylacrylamides, N-alkylmethacrylamide can thus sustain hydrogen bonding to relatively higher temperatures before seeking entropic compensation by undergoing volume collapse.

Characterization of molecular structures and properties of polyurethanes using molecular dynamics simulations.

Thermotropic polyurethanes with mesogenic groups in side chains were prepared from two diisocyanates and four diols with stoichiometric ratios of reactive isocyanate (NCO) and hydroxy (OH) groups. Their thermal behavior was determined by differential scanning calorimetry. The effect of structure modifications of the diisocyanates and diols, in particular changes in the mesogen, were investigated. Introduction of mesogenic segments into the polymers suppresses the ordering. Stiff end substituents (phenyl and alkoxy groups) of the mesogens stabilize the mesophases to such an extent that the negative influence of long polymer chains is compensated and the liquid-crystalline properties are recovered. All-atom molecular dynamics simulations in the Cerius2 modeling environment were carried out to characterize the structures of the polymers. Analysis of the dynamic trajectories at 20, 100, 120 and 170 degrees C revealed changes in conformation of macromolecules, which correlate with DSC measurements.

Swelling pressure induced phase-volume transition in hybrid biopolymer gels caused by unfolding of folded crosslinks: a model.

A thermodynamic model is proposed describing swelling changes and swelling transitions of hybrid gels in which domains of folded chains are chemically built in as cross-links. These folded domains can be unfolded to random coils by osmotic forces produced by the synthetic gel matrix. Uncoiling takes place if the osmotic force acting on the cross-links exceeds the critical value. By unfolding, a new interacting surface is exposed to interactions and affects the swelling pressure. The chains of the folded domains may have ionized groups. The model is based on mean-field statistical-thermodynamic treatment of swelling of polyelectrolyte gels with finite extensibility of network chains. This study is related to hybrid hydrogels with built in protein motifs. A continuous change in external variables increasing the degree of swelling of the hydrogel brings about an abrupt increase in volume (transition) of the gel. The position and magnitude of the transition depend on structural parameters of the hybrid gel, such as fraction of the folded domains in the gel, degree of ionization of chains in the domain, presence of additional chemical cross-links, or degree of dilution at gel formation. Two options for reversibility of the changes are considered: (a) unfolding is irreversible and deswelling proceeds along other curve than swelling and (b) swelling is reversible when the osmotic force decrease below the critical value. In the latter case, swelling changes are described by a closed loop with two transitions. Under certain conditions (high dilution at network formation and sufficiently high degree of ionization of chains of the folded domains), a transition appears known as the collapse transition induced by balance of hydrophobic and hydrophillic interactions. This collapse transition induces the folding transition by which the folded domains are reformed.

Molecular dynamics and IR spectroscopy in investigation of phase transitions in molecular crystal 4,4'-bis(11-hydroxy-1-undecyloxy)biphenyl.

Molecular dynamics (MD) simulations combined with temperature-dependent IR spectroscopic measurements were used to study phase transitions in molecular crystals of the mesogenic diol 4,4'-bis(11-hydroxy-1-undecyloxy)biphenyl. DSC measurements revealed four phase transitions in this molecular crystal at approximately 327.1 K, 389.8 K, 419.1 K and 431.9 K. Analysis of the dynamic trajectories at temperatures of 300 K, 360 K, 400 K and 480 K revealed changes in conformation of the mesogenic diol molecules and consequently changes in crystal packing and crystal structure in the temperature range 300-480 K and enabled us to understand the mechanism of the phase transitions.