Elementary structural building blocks encountered in silicon surface reconstructions

Driven by the reduction of dangling bonds and the minimization of surface stress, reconstruction of silicon surfaces leads to a striking diversity of outcomes. Despite this variety even very elaborate structures are generally comprised of a small number of structural building blocks. We here identify important elementary building blocks and discuss their integration into the structural models as well as their impact on the electronic structure of the surface

A new structural model for the Si(331)-(12x1) reconstruction

A new structural model for the Si(331)-(12x1) reconstruction is proposed. Based on scanning tunneling microscopy images of unprecedented resolution, low-energy electron diffraction data, and first-principles total-energy calculations, we demonstrate that the reconstructed Si(331) surface shares the same elementary building blocks as the Si(110)-(16x2) surface, establishing the pentamer as a universal building block for complex silicon surface reconstructions

Antibacterial β-Glucan/Zinc Oxide Nanocomposite Films for Wound Healing

Advanced antimicrobial biomaterials for wound healing applications are an active field of research for their potential in addressing severe and infected wounds and overcoming the threat of antimicrobial resistance. Beta-glucans have been used in the preparation of these materials for their bioactive properties, but very little progress has been made so far in producing biomedical devices entirely made of beta-glucans and in their integration with effective antimicrobial agents. In this work, a simple and eco-friendly method is used to produce flexible beta-glucan/nanostructured zinc oxide films, using glucans derived from the yeast Saccharomyces cerevisiae. The properties of the films are characterized through scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, infrared and UV–visible spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and water absorption tests. Finally, the antibacterial properties of the nanostructured zinc oxide and of the composite films are assessed against Staphylococcus epidermidis and Escherichia coli, showing a marked effectiveness against the former. Overall, this study demonstrates how a novel bionanocomposite can be obtained towards the development of advanced wound healing devices

Ab initio study of reflectance anisotropy spectra of a sub-monolayer oxidized Si(100) surface

The effects of oxygen adsorption on the reflectance anisotropy spectrum (RAS) of reconstructed Si(100):O surfaces at sub-monolayer coverage (first stages of oxidation) have been studied by an ab initio DFT-LDA scheme within a plane-wave, norm-conserving pseudopotential approach. Dangling bonds and the main features of the characteristic RAS of the clean Si(100) surface are mostly preserved after oxidation of 50% of the surface dimers, with some visible changes: a small red shift of the first peak, and the appearance of a distinct spectral structure at about 1.5 eV. The electronic transitions involved in the latter have been analyzed through state-by-state and layer-by-layer decompositions of the RAS. We suggest that new interplay between present theoretical results and reflectance anisotropy spectroscopy experiments could lead to further clarification of structural and kinetic details of the Si(100) oxidation process in the sub-monolayer range.Comment: 21 pages, 8 figures. To be published in Physical Rev.

A Low Rhodium Content Smart Catalyst for Hydrogenation and Hydroformylation Reactions

Abstract: This paper describes the preparation, broad characterization and study of activity in hydrogenation and hydroformylation reactions of an easily produced 0.18% Rh/Al2O3. Analytical studies on fresh and recycled samples shed light on the smart properties of such catalyst. Results showed high activity as well as fine/excellent chemoselectivity or regioselectivity, characteristics that may suggest a wide range of applicability. Graphic Abstract: The low metal content catalyst 0.18% Rh/Al2O3 was very active in both hydrogenation and hydroformylation reactions so providing intermediates for valuable APIs, as Nabumetone and Eletriptan, and a fragrance with a fresh, green-floral smell, that recalls scent of lily of the valley.[Figure not available: see fulltext.

cetuximab induced acneiform eruption and the response to isotretinoin

n/

Systematic review of exercise therapy in the management of post-thrombotic syndrome

Objectives Exercise improves haemodynamic parameters in patients with chronic venous disease. There is a paucity of evidence on its effect in post-thrombotic syndrome (PTS). The aim of this systematic review is to assess the impact of exercise in PTS. Methods Adhering to PRISMA guidelines and following PROSPERO registration (CRD42021220924), MEDLINE, Cochrane Library, EMBASE database, and trial registries were searched on 19th May 2022. Results One article met the inclusion criteria and a narrative synthesis was carried out. The included randomised controlled trial reported a between-group mean difference of 4.6 points (p = .027) in the VEINES-QOL score and −2.0 points (p = .14) in the Villalta score, in favour of exercise therapy. The statistical significance threshold was not reached. Conclusion Data on exercise in PTS remains sparse but exercise appears to be a safe intervention. In the context of this literature, a potential future trial and outcome reporting measures are suggested

Tranexamic acid-loaded mesoporous silica microspheres as a hemostatic material

Bleeding management is considered essential for saving life both in the military and civilian field. There is still a need to develop topical hemostats that can stop bleeding and be used easily in the trauma sites. The aim of this work is to develop a hemostat based on mesoporous silica particles with large pores for bleeding control. Mesoporous silica microspheres (MSM) with particle size of 1.5 − 5 µm and pores diameter of 25 nm have been successfully synthesized and, for the first time, loaded with tranexamic acid (TXA) with a content of 4.7%w/w. The hemostatic activity of both the pure material and TXA-loaded material (TXA@MSM) was investigated. It was found that the blood clotting time was significantly shortened by both systems with respect to control. A hemolysis assay was performed to evaluate the hemolytic activity of MSM, and the result indicated that the material was blood compatible. A preliminary TXA in vitro release test was performed, showing the complete release of TXA from the carrier within one hour. Considering the above results, TXA@MSM can be considered a promising material for the development of new hemostats