Fabrication, structure and properties of three-dimensional biodegradable poly(glycerol sebacate urethane) scaffolds

Large, three-dimensional, porous poly(glycerol sebacate urethane) (PGSU) scaffolds were fabricated via a solvent-based synthesis approach followed by freeze-drying and curing. The scaffolds showed highly interconnected open-cell structures with porosities and pore sizes in the ranges of 77–88% and 55–74 μm, respectively. The mechanical properties were measured in dry and hydrated states during quasi-static and cyclic tensile and compression tests. Hydrated PGSU scaffolds featured tensile Young moduli, ultimate tensile strengths and elongations at break in the ranges of 29–32 kPa, 12–19 kPa and 50–57%, respectively. In vitro degradation tests of the PGSU scaffolds presented adjustable degradation rates and mass losses of 10–16% and 30–62% without and with the presence of lipase enzyme in 112 days, respectively. This work illustrates that the large and porous PGSU scaffolds, characterised with flexible and soft mechanical properties, as well as long-term stability and adjustable degradation kinetics, have high potential for applications in soft tissue engineering

Ultrashort Bradycardic Effect of Newly Synthesized Compounds

Changes in the heart rate induced by four different doses of two newly synthesized potential ultrashort-action antagonists of beta adrenergic receptors were tested in 90 male laboratory Wistar rats. The isoprenaline-induced tachycardia model was used. Their effects were compared with those of esmolol. In the second part of the study, approximate electro-physiological measurements were made in vitro to assess the influence of the compounds tested on ion membrane currents in isolated ventricular cardiomyocytes. Both compounds demonstrated significant bradycardic effects in all concentrations tested compared with the control group, but they differed in the time of the onset of their action. Both newly synthesized compounds induced blockade of the fast sodium current (INa) and potassium currents (Ito, IK1, IK,end)

Differential scanning calorimetry of native silk feedstock

Native silk proteins, extracted directly from the silk gland prior to spinning, offer access to a naturally hydrated protein that has undergone little to no processing. Combined with differential scanning calorimetry (DSC), it is possible to probe the thermal stability and hydration status of silk and thus investigate its denaturation and solidification, echoing that of the natural spinning process. It is found that native silk is stable between -10 °C and 55 °C, and both the high-temperature enthalpy of denaturation (measured via modulated temperature DSC) and a newly reported low-temperature ice-melting transition may serve as useful quality indicators in the future for artificial silks. Finally, compared to albumin, silk's denaturation enthalpy is much lower than expected, which is interpreted within a recently proposed entropic desolvation framework which can serve to unveil the low-energy aquamelt processing pathway

Introduction : From Fundamentals to Advances in Crowdfunding Research and Practice

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Experimental discrimination of ion stopping models near the Bragg peak in highly ionized matter

The energy deposition of ions in dense plasmas is a key process in inertial confinement fusion that determines the α-particle heating expected to trigger a burn wave in the hydrogen pellet and resulting in high thermonuclear gain. However, measurements of ion stopping in plasmas are scarce and mostly restricted to high ion velocities where theory agrees with the data. Here, we report experimental data at low projectile velocities near the Bragg peak, where the stopping force reaches its maximum. This parameter range features the largest theoretical uncertainties and conclusive data are missing until today. The precision of our measurements, combined with a reliable knowledge of the plasma parameters, allows to disprove several standard models for the stopping power for beam velocities typically encountered in inertial fusion. On the other hand, our data support theories that include a detailed treatment of strong ion-electron collisions

High-pressure chemistry of hydrocarbons relevant to planetary interiors and inertial confinement fusion

Diamond formation in polystyrene (C8H8)n, which is laser-compressed and heated to conditions around 150 GPa and 5000 K, has recently been demonstrated in the laboratory [Kraus et al., Nat. Astron. 1, 606–611 (2017)]. Here, we show an extended analysis and comparison to first-principles simulations of the acquired data and their implications for planetary physics and inertial confinement fusion. Moreover, we discuss the advanced diagnostic capabilities of adding high-quality small angle X-ray scattering and spectrally resolved X-ray scattering to the platform, which shows great prospects of precisely studying the kinetics of chemical reactions in dense plasma environments at pressures exceeding 100 GPa

Recovery of release cloud from laser shock-loaded graphite and hydrocarbon targets: in search of diamonds

This work presents first insights into the dynamics of free-surface release clouds from dynamically compressed polystyrene and pyrolytic graphite at pressures up to 200 GPa, where they transform into diamond or lonsdaleite, respectively. These ejecta clouds are released into either vacuum or various types of catcher systems, and are monitored with high-speed recordings (frame rates up to 10 MHz). Molecular dynamics simulations are used to give insights to the rate of diamond preservation throughout the free expansion and the catcher impact process, highlighting the challenges of diamond retrieval. Raman spectroscopy data show graphitic signatures on a catcher plate confirming that the shock-compressed PS is transformed. First electron microscopy analyses of solid catcher plates yield an outstanding number of different spherical-like objects in the size range between ten(s) up to hundreds of nanometres, which are one type of two potential diamond candidates identified. The origin of some objects can unambiguously be assigned, while the history of others remains speculative