Search results for "composites"

Polyaspartamide-polylactide electrospun scaffolds for potential topical release of Ibuprofen.

2012

In this work, the production and characterization of electrospun scaffolds of the copolymer α,β-poly(N-2-hydroxyethyl)-DL-aspartamide-graft-polylactic acid (PHEA-g-PLA), proposed for a potential topical release of Ibuprofen (IBU), are reported. The drug has been chemically linked to PHEA-g-PLA and/or physically mixed to the copolymer before electrospinning. Degradation studies have been performed as a function of time in Dulbecco phosphate buffer solution pH 7.4, for both unloaded and drug-loaded scaffolds. By using an appropriate ratio between drug physically blended to the copolymer and drug-copolymer conjugate, a useful control of its release can be obtained. MTS assay on human dermal fi…

Characterization of the complete fiber network topology of planar fibrous tissues and scaffolds

2010

Understanding how engineered tissue scaffold architecture affects cell morphology, metabolism, phenotypic expression, as well as predicting material mechanical behavior has recently received increased attention. In the present study, an image-based analysis approach that provides an automated tool to characterize engineered tissue fiber network topology is presented. Micro-architectural features that fully defined fiber network topology were detected and quantified, which include fiber orientation, connectivity, intersection spatial density, and diameter. Algorithm performance was tested using scanning electron microscopy (SEM) images of electrospun poly(ester urethane)urea (ES-PEUU) scaffo…

Heparin functionalized polyaspartamide/polyester scaffold for potential blood vessel regeneration

2013

An interesting issue in tissue engineering is the development of a biodegradable vascular graft able to substitute a blood vessel and to allow its complete regeneration. Here, we report a new scaffold potentially useful as a synthetic vascular graft, produced through the electrospinning of α,β-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-D,L-aspartamide-graft-polylactic acid (PHEA-EDA-g-PLA) in the presence of polycaprolactone (PCL). The scaffold degradation profile has been evaluated as well as the possibility to bind heparin to electrospun fibers, being it a known anticoagulant molecule able to bind growth factors. In vitro cell compatibility has been investigated using human vascular e…

Preparation and characterization of a biologic scaffold from esophageal mucosa

2013

Biologic scaffolds composed of extracellular matrix (ECM) are commonly used to facilitate a constructive remodeling response in several types of tissue, including the esophagus. Surgical manipulation of the esophagus is often complicated by stricture, but preclinical and clinical studies have shown that the use of an ECM scaffold can mitigate stricture and promote a constructive outcome after resection of full circumference esophageal mucosa. Recognizing the potential benefits of ECM derived from homologous tissue (i.e., site-specific ECM), the objective of the present study was to prepare, characterize, and assess the in-vivo remodeling properties of ECM from porcine esophageal mucosa. The…

Selective and Sensitive Chromogenic Detection of Cyanide and HCN in Solution and in Gas Phase

2013

Two triphenylmethane based chemodosimeters for selective and chromogenic sensing of cyanide anions in aqueous environments and of hydrogen cyanide in gas phase were prepared and studied.

Isoelectronic series of twofold coordinated Si, Ge, and Sn atoms in glassy SiO2: a luminescence study

1992

Abstract Luminescence centers causing optical absorption bands in the 5 eV region in oxygen-deficient pure (‘Si-doped’), as well as in Ge- and Sn-doped glassy SiO2 were studied. The spectral and particularly kinetic data show that in all cases luminescence centers with closely similar properties exist which constitute an isoelectronic series. They are attributed to defects, formed by electrically neutral twofold coordinated Si, Ge, and Sn atoms (T20 centers) in glassy SiO2. Twofold coordinated Si causes the characteristic ‘B2’ optical absorption band at 5.03 eV. Upon reaction with atomic hydrogen, T20 centers convert to the well known ‘H(I)’, ‘H(II)’ and ‘H(III)’ ESR-active defects. The alt…

Dynamic composition of services : application to designing and developping information systems in a distributed environment

2010

The service oriented computing paradigm plays an increasingly important role in structuring complex systems. Application design and development approaches are witnessing a shift from traditional models towards a more dynamic service oriented model promoting reuse and adaptability. In this thesis, we study an approach for application design and development based on services’ composition. We propose DyCoSe, an environment for sharing services. It consists of an enterprise ecosystem wherein members, organized in communities, share a global agreement describing traditional business functionalities and common non-functional properties. DyCoSe relies on a three level architecture for service base…

Influence of the Substituent on Selective Photocatalytic Oxidation of Aromatic Compounds in Aqueous TiO2 Suspensions.

2006

Experimental results are reported showing that the photocatalytic oxidation of aromatic compounds containing an electron-donor group (EDG) gives rise mainly to ortho- and para-monohydroxy derivatives while in the presence of an electron-withdrawing group (EWG) all the monohydroxy derivatives are obtained.

Preparation and photocatalytic activity of ZnO-SnO2, ZnO-ZnWO4 and SnO2-ZnO-ZnWO4 nanocomposites

2014

Printable Thermo- and Photo-stable Poly(D,L-lactide)/Carbon Nanodots Nanocomposites via Heterophase Melt-Extrusion Transesterification

2022

We propose for the first time an one-pot synthesis of carbon nanodots-poly(D,L-lactide) (CDs-PLA) nanocomposites, obtained by a simple reactive melt-extrusion process involving polar surface groups of multicolor CDs and ester bonds of PLA chains. Apart from providing an excellent method to produce polyester-coated CDs, our protocol allows obtaining perfect PLA@CDs blends giving rise to homogeneous extruded PLA@CDs filaments (ePLA@CDs) suitable for 3D printing applications (e.g., additive manufacturing for biomaterials and biodegradable encoded polymer ink technology). We demonstrate that ePLA@CDs filaments can be used to build a huge range of fluorescent objects with increasing architectura…