Functionalization of 3D Polylactic Acid Sponge Using Atmospheric Pressure Cold Plasma

The deposition of organic functionalities on biomaterials to immobilize biomolecules is a research area of great interest in the medical field. The surface functionalization of a 3D porous scaffolds of PDLLA with carboxyl (-COOH) and amino (-NH2) groups by cold plasma treatment at atmospheric pressure is described in this paper. Two methods of continuous and pulsed plasma deposition were compared to assess the degree of functionalization of the internal porous 3D scaffold. In particular, the pulsed plasma treatment was found to functionalize uniformly not only the sample surface but also inside the open cavities thanks to its permeability and diffusion in the porous 3D scaffold. The species developed in the plasma were studied by optical emission spectroscopy (OES) technique, while the functionalization of the sponges was evaluated by the Diffuse Reflectance Fourier-Transform Infrared Spectroscopy (DR-FTIR) technique using also the adsorption of ammonia (NH3) and deuterated water (D2O) probe molecules. The functional groups were deposited only on the front of the sponge, then the structural characterization of both front and back of the sponge has demonstrated the uniform functionalization of the entire scaffold

1α,25-Dihydroxycholecalciferol (Vitamin D3) induces NO-dependent endothelial cell proliferation and migration in a three-dimensional matrix.

Background/Aims: The 1α,25-dihydroxycholecalciferol (Vit. D) induces eNOS dependent nitric oxide (NO) production in human umbilical vein endothelial cells (HUVEC). To our knowledge, there are no reports directly relating Vit. D induced NO production to proliferation and/or migration in endothelial cells (EC). The aim of this study was to evaluate whether Vit. D addition to porcine EC could affect their proliferation and/or migration in a three-dimensional matrix via NO production. Materials and Methods: Porcine aortic endothelial cells (PAE) were used to evaluate Vit. D effects on cell proliferation and migration in a three-dimensional matrix. Results: Vit. D induced NO production in PAE cells. Moreover, it induced a significant increase in cellular proliferation and migration in a three-dimensional matrix. These effects were NO dependent, as inhibiting eNOS activity by L-NAME PAE migration was abrogated. This effect was strictly related to MMP-2 expression and apparently dependent on Vit. D and NO production. Conclusions: Vit. D can promote both endothelial cells proliferation and migration in a three-dimensional matrix via NO-dependent mechanisms. These findings cast new light on the role of Vit. D in the angiogenic process, suggesting new applications for Vit. D in such fields as tissue repair and wound healing

Search for nu(mu)-->nu(e) Oscillations in the NOMAD Experiment

We present the results of a search for nu(mu)-->nu(e) oscillations in the NOMAD experiment at CERN. The experiment looked for the appearance of nu(e) in a predominantly nu(mu) wide-band neutrino beam at the CERN SPS. No evidence for oscillations was found. The 90% confidence limits obtained are delta m^2 < 0.4 eV^2 for maximal mixing and sin^2(2theta) < 1.4x10^{-3} for large delta m^2. This result excludes the LSND allowed region of oscillation parameters with delta m^2 > 10 eV^2.Comment: 19 pages, 8 figures. Submitted to Phys. Lett.

Discrete-time volatility forecasting with persistent leverage effect and the link with continuous-time volatility modeling

We first propose a reduced-form model in discrete time for S&P 500 volatility showing that the forecasting performance can be significantly improved by introducing a persistent leverage effect with a long-range dependence similar to that of volatility itself. We also find a strongly significant positive impact of lagged jumps on volatility, which however is absorbed more quickly. We then estimate continuous-time stochastic volatility models that are able to reproduce the statistical features captured by the discrete-time model. We show that a single-factor model driven by a fractional Brownian motion is unable to reproduce the volatility dynamics observed in the data, while a multifactor Markovian model fully replicates the persistence of both volatility and leverage effect. The impact of jumps can be associated with a common jump component in price and volatility

The TopClosure® 3S System, for skin stretching and a secure wound closure

The principle of stretching wound margins for primary wound closure is commonly practiced and used for various skin defects, leading at times to excessive tension and complications during wound closure. Different surgical techniques, skin stretching devices and tissue expanders have been utilized to address this issue. Previously designed skin stretching devices resulted in considerable morbidity. They were invasive by nature and associated with relatively high localized tissue pressure, frequently leading to necrosis, damage and tearing of skin at the wound margins. To assess the clinical effectiveness and performance and, to determine the safety of TopClosure® for gradual, controlled, temporary, noninvasive and invasive applications for skin stretching and secure wound closing, the TopClosure® device was applied to 20 patients for preoperative skin lesion removal and to secure closure of a variety of wound sizes. TopClosure® was reinforced with adhesives, staples and/or surgical sutures, depending on the circumstances of the wound and the surgeon’s judgment. TopClosure® was used prior to, during and/or after surgery to reduce tension across wound edges. No significant complications or adverse events were associated with its use. TopClosure® was effectively used for preoperative skin expansion in preparation for dermal resection (e.g., congenital nevi). It aided closure of large wounds involving significant loss of skin and soft tissue by mobilizing skin and subcutaneous tissue, thus avoiding the need for skin grafts or flaps. Following surgery, it was used to secure closure of wounds under tension, thus improving wound aesthetics. A sample case study will be presented. We designed TopClosure®, an innovative device, to modify the currently practiced concept of wound closure by applying minimal stress to the skin, away from damaged wound edges, with flexible force vectors and versatile methods of attachment to the skin, in a noninvasive or invasive manner

The effect of starch-based biomaterials on leukocyte adhesion and activation in vitro

Leukocyte adhesion to biomaterials has long been recognised as a key element to determine their inflammatory potential. Results regarding leukocyte adhesion and activation are contradictory in some aspects of the material’s effect in determining these events. It is clear that together with the wettability or hydrophilicity/hydrophobicity, the roughness of a substrate has a major effect on leukocyte adhesion. Both the chemical and physical properties of a material influence the adsorbed proteins layer which in turn determines the adhesion of cells. In this work polymorphonuclear (PMN) cells and a mixed population of monocytes/macrophages and lymphocytes (mononuclear cells) were cultured separately with a range of starch-based materials and composites with hydroxyapatite (HA). A combination of both reflected light microscopy and scanning electron microscopy (SEM) was used in order to study the leukocyte morphology. The quantification of the enzyme lactate dehydrogenase (LDH) was used to determine the number of viable cells adhered to the polymers. Cell adhesion and activation was characterised by immunocytochemistry based on the expression of several adhesion molecules, crucial in the progress of an inflammatory response. This work supports previous in vitro studies with PMN and monocytes/macrophages, which demonstrated that there are several properties of the materials that can influence and determine their biological response. From our study, monocytes/macrophages and lymphocytes adhere in similar amounts to more hydrophobic (SPCL) and to moderately hydrophilic (SEVA-C) surfaces and do not preferentially adhere to rougher substrates (SCA). Contrarily, more hydrophilic surfaces (SCA) induced higher PMN adhesion and lower activation. In addition, the hydroxyapatite reinforcement induces changes in cell behaviour for some materials but not for others. The observed response to starch-based biodegradable polymers was not significantly different from the control materials. Thus, the results reported herein indicate the low potential of the starch-based biodegradable polymers to induce inflammation especially the HA reinforced composite materials

Non-standard errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants