1,473 research outputs found
Fabrication and properties of L-arginine-doped PCL electrospun composite scaffolds
The article describes fabrication and properties of composite fibrous
scaffolds obtained by electrospinning of the solution of
poly({\epsilon}-caprolactone) and arginine in common solvent. The influence of
arginine content on structure, mechanical, surface and biological properties of
the scaffolds was investigated. It was found that with an increase of arginine
concentration diameter of the scaffold fibers was reduced, which was
accompanied by an increase of scaffold strength and Young modulus. It was
demonstrated that porosity and water contact angle of the scaffold are
independent from arginine content. The best cell adhesion and viability was
shown on scaffolds with arginine concentration from 0.5 to 1 % wt
Gravity Effect on Electrical Field Generation and Charge Carriers Transfer During Combustion Synthesis of Sulfides
The effect of gravity on the electric potential generated by the combustion synthesis of zinc sulfide is analyzed using the numerical simulation. Recent experimental studies on generation of electric voltage during combustion synthesis of zinc sulfide (ZnS) have revealed high voltage signals (4 V) with duration about 1 s, which are much higher than those produced by the gasāsolid and solidāsolid combustion reactions studied previously. These data have raised the question about mechanism of such a phenomenon. In our previous work we developed a novel (distributed) model describing the electric potential generation during combustion synthesis of sulfides (CSS) that didn\u27t count the effect of gravity. In this paper the simulations of heat - mass transfer, charge carriers motion, and voltage profiles taking into account the Earth gravity effect. The simulations confirms that the gravitation force strongly affects the emission of negatively charged sulfur ions as well as electrons and has a significant impact on the amplitude and temporal evolution of the combustion induced voltage. The voltage reduction up to four times has been observed numerically in the case when gravity acts in the direction coincident to that of the propagating combustion wave. Vice versa, the significant acceleration of the combustion and the voltage amplification due to the advection is simulated when gravity acts in the direction opposite to that of the propagating combustion wave
Temperature independent diffuse scattering and elastic lattice deformations in relaxor PbMg1/3Nb2/3O3
The results of diffuse neutron scattering experiment on PbMg1/3Nb2/3O3 single
crystal above the Burns temperature are reported. It is shown that the high
temperature elastic diffuse component is highly anisotropic in low-symmetry
Brillouin zones and this anisotropy can be described using Huang scattering
formalism assuming that the scattering originates from mesoscopic lattice
deformations due to elastic defects. The qualitative agreement between this
model and the experimental data is achieved with simple isotropic defects. It
is demonstrated that weak satellite maxima near the Bragg reflections can be
interpreted as the finite resolution effect.Comment: 7 pages, 7 figure
Transverse Pressure and Strangeness Dynamics in Relativistic Heavy Ion Reactions
Transverse hadron spectra from proton-proton, proton-nucleus and
nucleus-nucleus collisions from 2 AGeV to 21.3 ATeV are investigated within two
independent transport approaches (HSD and UrQMD). For central Au+Au (Pb+Pb)
collisions at energies above 5 AGeV, the measured
transverse mass spectra have a larger inverse slope parameter than expected
from the default calculations. The additional pressure - as suggested by
lattice QCD calculations at finite quark chemical potential and
temperature - might be generated by strong interactions in the early
pre-hadronic/partonic phase of central Au+Au (Pb+Pb) collisions. This is
supported by a non-monotonic energy dependence of in the present
transport model.Comment: Proceedings of Strange Quark Matter 200
Prostaglandin H synthase kinetics in the two-phase aqueous-micellar system
AbstractReaction mixture for PGHS (prostaglandin-H-synthase) is a two-phase system including micellar hydrophobic phase and hydrophilic aqueous phase. Reagents added to the mixture are distributed between phases, thus concentrations of reagents dissolved in phases can differ significantly from their overall contents.Using dynamic light scattering we found that the hydrophobic phase produced by tween-20 consists of micelles, which radius (4ā5nm) does not depend on either tween-20 overall content (0.1%ā1% v/v) or arachidonic acid (AA) addition (10ā1000Ī¼M) or PGHS addition (1Ī¼M).Tween-20 overall content changing from 0.1% to 2% v/v dramatically affected COX kinetic, but accounting AA distribution between phases allowed us to estimate ātrueā parameters, independent of the tween-20 overall content and the concentration of another substrate: KMOx equals 9.8Ī¼M O2 in the aqueous phase or 0.0074bar in the gaseous phase, KMAA equals 5400Ī¼M AA in the phase of tween-20 micelles and 5400/PĪ¼M AA in the aqueous phase (P is the distribution ratio for the AA between the aqueous phase and the hydrophobic phase (Pā«1000)). This approach allowed to evaluate PS, the distribution ratio for the AA between the hydrophobic phase and the PGHS active center (PS ~310). This coefficient indicates the AA selectivity toward the cyclooxygenase active center
THE INFLUENCE OF CONCOMITANT CARDIOVASCULAR PATHOLOGY (ISCHEMIC HEART DISEASE AND ARTERIAL HYPERTENSION) ON THE CHANGES OF RIGHT VENTRICLE OF HEART IN MINERS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE
Associated cardiovascular pathology (ischemic heart disease and arterial hypertension.) in miners with chronic obstructive pulmonary disease increases the degree of hypertrophy of myocardium of right ventricle of heart and worsens its systolic and diastolic functions
Adatom diffusion on vicinal surfaces with permeable steps
We study the behavior of single atoms on an infinite vicinal surface assuming
certain degree of step permeability. Assuming complete lack of re-evaporation
an ruling out nucleation the atoms will inevitably join kink sites at the steps
but can do many attempts before that. Increasing the probability of step
permeability or the kink spacing lead to increase of the number of steps
crossed before incorporation of the atoms into kink sites. The asymmetry of the
attachment-detachment kinetics (Ehrlich-Schwoebel effect) suppresses the step
permeability and completely eliminates it in the extreme case of infinite
Ehrlich-Schwoebel barrier. The average number of permeability events per atom
scales with the average kink spacing. A negligibly small drift of the adatoms
in a direction perpendicular to the steps leads to a significant asymmetry of
the distribution of the permeability events the atoms thus visiting more
distant steps in the direction of the drift.Comment: 12 pages, 6 figure
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