Effect of Low-Temperature Plasma Jet on Thermal Stability and Physical Structure of Type I Collagen

This work is devoted to the characterization of type I collagen treated by a low-temperature plasma jet generated in ambient air to determine whether the resulting fibrous material is structurally preserved or reinforced. The physical structure of collagen is checked by differential scanning calorimetry (DSC), which is a well suited technique to analyze thermal transitions in proteins, such as denaturation. DSC is used to evaluate the thermal stability of collagen after the plasma treatments while Fourier transform infra red spectroscopy is used to check the integrity of triple helical domain and to investigate the effects of plasma treatments on the functional groups of collagen. It is more particularly shown that the plasma treatment can stabilize the collagen structure without altering the triple helical structure. This observation is supported by 1) the shift observed toward high-temperature range of the collagen denaturation and 2) the stiffening of the chains by a cross-linking action when compared to the control sample

The Inhibitory Effect of Resveratrol on Elastin Amyloidogenesis

The role of polyphenols in the prevention of degenerative diseases is emerging in the last years. In this report, we will investigatein vitrothe inhibitory effect of resveratrol on elastin amyloidogenesis. The effect of resveratrol on molecular structure was investigated by circular dichroism spectroscopy, while the inhibitory effect on self-assembly was evaluated by turbidimetry as a function of temperature and by atomic force microscopy

Amyloidogenesis of proteolytic fragments of human elastin

Some polypeptides encoded by the C-terminal region of human tropoelastin gene have been demonstrated to be amyloidogenic in vitro. The biological relevance of this finding is still under investigation given that only limited evidence concerning the involvement of elastin in amyloidosis exists. Recent studies identified, by mass spectrometry, several elastin fragments produced from the cleavages made by some elastases in human elastin substrate. Some of these fragments are contained into the same polypeptide sequences previously demonstrated to be amyloidogenic. Our hypothesis is that the upregulation of elastases in inflammatory processes triggered, for example, by aging induces the release of elastin fragments potentially amyloidogenic. Therefore our aim in this study is to demonstrate if any of these fragments is amyloidogenic in vitro. At molecular level, CD, NMR, FTIR spectroscopies and MD simulations were used, while, at supramolecular level, Congo red binding assay and ThT fluorescence spectroscopy complemented with AFM microscopy were carried out. Our results show that the longest peptide, among those synthesized and mimicking the elastin fragments produced by elastases on human elastin, constituted of 22 residues, is able to aggregate into amyloid-like fibres. These findings support the hypothesis of amyloidogenesis of proteolytic fragments of elastin

Self-assembling peptide-enriched electrospun polycaprolactone scaffolds promote the h-osteoblast adhesion and modulate differentiation-associated gene expression

Electrospun polycaprolactone (PCL) is able to support the adhesion and growth of h-osteoblasts and to delay their degradation rate to a greater extent with respect to other polyesters. The drawbacks linked to its employment in regenerative medicine arise fromits hydrophobic nature and the lack of biochemical signals linked to it. This work reports on the attempt to add five different self-assembling (SA) peptides to PCL solutions before electrospinning. The hybrid scaffolds obtained had regular fibers (SEM analysis) whose diameters were similar to those of the extracellularmatrix, more stable hydrophilic (contact angle measurement) surfaces, and anamorphous phase constrained by peptides (DSC analysis). They appeared to have a notable capacity to promote the h-osteoblast adhesion and differentiation process by increasing the gene expression of alkaline phosphatase, bone sialoprotein, and osteopontin. Adding an Arg-Gly-Asp (RGD) motif to a self-assembling sequence was found to enhance cell adhesion, while the same motif condensed with a scrambled sequence did not, indicating that there is a cooperative effect between RGD and 3D architecture created by the self-assembling peptides. The study demonstrates that self-assembling peptide scaffolds are still able to promote beneficial effects on h-osteoblasts even after they have been included in electrospun polycaprolactone. The possibility of linking biochemical messages to self-assembling peptides could lead the way to a 3D decoration of fibrous scaffolds

Hybrid cosmic ray measurements using the IceAct telescopes in coincidence with the IceCube and IceTop detectors

IceAct is a proposed surface array of compact (50 cm diameter) and cost-effective Imaging Air Cherenkov Telescopes installed at the site of the IceCube Neutrino Observatory at the geographic South Pole. Since January 2019, two IceAct telescope demonstrators, featuring 61 silicon photomultiplier (SiPM) pixels have been taking data in the center of the IceTop surface array during the austral winter. We present the first analysis of hybrid cosmic ray events detected by the IceAct imaging air-Cherenkov telescopes in coincidence with the IceCube Neutrino Observatory, including the IceTop surface array and the IceCube in-ice array. By featuring an energy threshold of about 10 TeV and a wide field-of-view, the IceAct telescopes show promising capabilities of improving current cosmic ray composition studies: measuring the Cherenkov light emissions in the atmosphere adds new information about the shower development not accessible with the current detectors, enabling significantly better primary particle type discrimination on a statistical basis. The hybrid measurement also allows for detailed feasibility studies of detector cross-calibration and of cosmic ray veto capabilities for neutrino analyses. We present the performance of the telescopes, the results from the analysis of two years of data, and an outlook of a hybrid simulation for a future telescope array

Study of densification mechanisms during Spark Plasma Sintering of co-precipitated Ho:Lu2O3 nanopowders: Application to transparent ceramics for lasers

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