Search results for "Oxide"

Sterilization of three-dimensional tissue engineering scaffolds by supercritical carbon dioxide

2014

Medical devices, implants or patient-care equipment that will come into intimate contact with a patient must be effectively decontaminated to prevent infection or disease transmission. Non-sterile devices have significant ramifications for patient morbidity and mortality and two processes must be undertaken in order to make an item acceptable for use or implantation: cleaning and disinfection (or sterilization) [1]. Sterilization is the destruction of living organisms, and must be done without damaging the material surface and without compromising the bulk material strength or biocompatibility of implantable device. Common sterilization processes include steam autoclaving, gamma irradiation…

Photoluminescence and Electron Spin Resonance of Silicon Dioxide Crystal with Rutile Structure (Stishovite)

2018

This work was supported by ERANET MYND. Also, financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2017/2 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. The authors express our gratitude to R.I. Mashkovtsev for help in ESR signal interpretation. The authors are appreciative to T.I. Dyuzheva, L.M. Lityagina, N.A. Bendeliani for stishovite single crystals and to K. Hubner and H.-J. Fitting for stishovite powder of Barringer Meteor Crater.

Characterization of rhenium oxide films and their application to liquid crystal cells

2009

Rhenium trioxide exhibits high electronic conductivity, while its open cubic crystal structure allows an appreciable hydrogen intercalation, generating disordered solid phases, with protonic conductivity. Rhenium oxide thin films have been obtained by thermal evaporation of ReO3 powders on different substrates, maintained at different temperatures, and also by reactive magnetron sputtering of a Re metallic target. A comparative investigation has been carried out on these films, by using micro-Raman spectroscopy and x-ray diffraction. Two basic types of solid phases appear to grow in the films: a red metallic HxReO3 compound, with distorted perovskite structures, like in the bulk material, a…

Chemical composition of the essential oil of Centaurea grinensis Reuter and Centaurea apiculata Ledeb: Growing wild in Croatia and Bulgaria, respecti…

2016

AbstractIn the present study, the chemical composition of the essential oils from aerial parts of Centaurea grinensis Reuter (K) collected at Žuta Lova, near Senj (Croatia), and aerial parts (L1) and flowers (L2) of C. apiculata Ledeb. collected near Rebro village, near Breznik town, Znepole Region (Bulgaria), both belonging to subgenus Lopholoma (Cass.) Dobrocz, was evaluated by GC and GC-MS. The main components of K were 4-vinyl guaiacol (21.5%), hexadecanoic acid (16.2%), acetophenone (12.5%). Caryophyllene oxide (15.8%) together with sphathulenol (14.5%) and humulene epoxide II (9.4%) were recognized as the main constituent of both the aerial part (L1) and flowers (L2) of C. apiculata. …

Effects of nitric oxide and cGMP-active compounds on neuronal activity of substantia nigra pars reticulata: a rat in vivo study

2009

1,2,6-Thiadiazine 1-Oxides: Unsaturated Three-Dimensional S,N-Heterocycles from Sulfonimidamides.

2020

Unprecedented three-dimensional 1,2,6-thiadiazine 1-oxides have been prepared by an aza-Michael-addition/cyclization/condensation reaction sequence starting from sulfonimidamides and propargyl ketones. The products have been further functionalized by standard cross-coupling reactions, selective bromination of the heterocyclic ring, and conversion into a β-hydroxy substituted derivative. A representative product was characterized by single-crystal X-ray structure analysis. peerReviewed

A one-pot method to enhance dissolution rate of low solubility drug molecules using dispersion polymerization in supercritical carbon dioxide

2009

Preparation of pH sensitive poly(vinilydenefluoride) porous membranes by grafting of acrylic acid assisted by supercritical carbon dioxide

2010

Aim of this work is to study the preparation of pH sensitive membranes for biomedical applications via thermal induced graft polymerization of acrylic acid (AA) on poly(vinilydenefluoride) (PVDF) assisted by supercritical carbon dioxide (scCO2). Using scCO2 as a solvent and swelling agent, the monomer and initiator (benzoyl peroxide) could diffuse faster and distribute more uniformly into the polymer matrix. A better control of the final molecular architecture should be achieved because bimolecular grafting reactions are accelerated with respect to chain degradation processes. Commercial hydrophobic PVDF porous matrixes were selected as model membranes. Grafted polymers were characterized b…

Melt phase ring opening polymrization of lactide and glycolide assisted by supercritical carbon dioxide

2010

Supercritical carbon dioxide induces sterilization of PLLA scaffolds contaminated by E. coli.

2014

The common sterilization techniques are based on physical processes that involve, for example, the use of autoclaves or systems to radiation such as γ-rays that can cause a structural change of the polymer treated. Therefore, the use of supercritical carbon dioxide (scCO2) is an excellent alternative, as it does not induce any variation of biomaterials treated (Perrut M., 2012). It's a good candidate because is readily available at low cost, non-toxic and non-flammable, it has an easily accessible critical point (7.38 MPa and 304.2 K) and excellent transport properties and wettability (White A. et al., 2005). We report the development of a supercritical CO2 based process capable of steriliz…