Search results for "GRAFTING"
showing 10 items of 201 documents
Chemical modification of halloysite nanotubes for controlled loading and release.
2020
Clay minerals have been used for medical purposes from ancient times. Among them, the halloysite nanotube, an aluminosilicate of the kaolin group, is an emerging nanomaterial which possesses peculiar chemical characteristics. By means of suitable modifications, such as supramolecular functionalization or covalent modifications, it is possible to obtain novel nanomaterials with tunable properties for several applications. In this context the covalent grafting of suitable organic moieties on the external surface or in the halloysite lumen has been exploited to improve the loading and release of several biologically active molecules. The resulting hybrid nanomaterials have been applied as drug…
Congenital penile curvature: dermal grafting procedure to prevent penile shortening in adults.
2007
Objectives: We report the results of a derma graft corporoplasty in a selected group of patients with congenital penile curvature (CPC) who refused a simple plication technique for the risk of penile shortening, even if minimal. Methods: Between January 1995 and January 2004, 15 potent patients with CPC underwent corporoplasty with inguinal derma graft, with or without tunica albuginea plication. Mean age was 26.6 years (range 1936). Six patients had a simple lateral left curvature, three had a simple lateral right curvature, four had a ventro-lateral left curvature, one patient had a ventro-lateral right curvature, and one patient had ventral curvature. In nine patients the preoperative me…
Corticotomy-assisted orthodontics
2011
The use of orthodontic treatment in adult patients is becoming more common and these patients have different requirements specially regarding duration of treatment and facial and dental aesthetics. Alveolar corticotomy is an effective means of accelerating orthodontic treatment. This literature revision include an historical background, biological and orthodontic fundamentals and the most significant clinical applications of this technique. Orthodontic treatment time is reduced with this technique to one-third of that in conventional orthodontics. Alveolar bone grafting of labial and palatal/lingual surfaces ensures root coverage as the dental arch is expanded. Corticotomy-assisted orthodon…
Immediate Loading in Atrophic Jaws: Zygomatic Implants
2019
The zygomatic fixture is an extended length (35–55 mm) titanium implant, placed into the zygomatic and maxillary alveolar bone. It was designed for situations where atrophy of the posterior maxilla complicates or prevents the placing of conventional implants. The use of zygomatic implants avoids the need for bone grafting, shortens treatment times, and reduces morbidity. They have also been used in patients with maxillectomies resulting from tumors or diseases associated with atrophic conditions of the maxilla.
ALLOGENEIC BONE GRAFTING MATERIALS – UPDATE OF THE CURRENT SCIENTIFIC STATUS
2017
Worldwide population aging and associated with it epidemics of osteoporosis, widespread of bone and joint reconstructive surgery and first of all joint replacement lead to explosive growth of interest in bone grafting.Although autografts are still the golden standard in bone regeneration, allogeneic bone substitutes have reached a state that allows for their application with satisfying clinical results. However, it has repeatedly been supposed that the different allogeneic materials underwent different purification processes, which modifies bone regeneration properties of these materials and also for different safety conditions. In the present publication, the treatment of the precursor tis…
Preparation of pH sensitive poly(vinilydenefluoride) porous membranes by grafting of acrylic acid assisted by supercritical carbon dioxide
2012
Free radical grafting of acrylic acid (AA) on poly(vinilydenefluoride) (PVDF) porous membranes was studied at 65°C using supercritical carbon dioxide (scCO 2) as a solvent and delivery agent. The process was initiated by the thermal decomposition of benzoylperoxide (BPO). Spectroscopic analyses confirmed the presence of poly(AA) chains linked to treated membranes. The mass fraction of grafted AA increased with grafting time and BPO concentration while it decreased when the density of the fluid phase was enhanced. A not-monotonic trend was obtained when the effect of the initial AA concentration was studied. The grafting process was accompanied by a reduction of the crystallinity of the PVDF…
Modification of EVOH copolymers with e-caprolactone: synthesis and compatibilization effects in PE/PVC blends
2001
Polyethylene-polycaprolactone graft copolymers with different chemical structures (i.e. different number and length of PCL grafts and molecular weight of PE backbone) were synthesized from various EVOH copolymers and e-caprolactone, using Aluminum isopropoxide as catalyst, and were tested for their compatibilizing capability in PE/PVC blends. PE and PCL segments in the graft copolymers were found completely immiscible, while PCL segments of the graft copolymers were found completely miscible with PVC. When graft copolymers were added to PE/PVC blends they proved to be good agents for the dispersion of PVC phase in the PE matrix. SEM showed also improved adhesion between the dispersed PVC ph…
Grafting of hyperbranched polymers: From unusual complex polymer topologies to multivalent surface functionalization
2013
Abstract In this feature article, the grafting of hyperbranched polymers to different substrates is reviewed. Both grafting onto macromolecules with different topologies (homogeneous grafting) and the resulting complex polymer architectures containing highly branched segments as well as their applications are discussed. In the second part grafting of hyperbranched polymers on surfaces, i.e., planar surfaces and spherical particles (heterogeneous grafting), with respect to specific applications, such as bio-repellent surfaces or soluble carbon nanotubes is described. In all cases, the one-step synthesis and the resulting highly branched topology of the hyperbranched building blocks is benefi…
The Influence of PRP on Early Bone Formation in Membrane Protected Defects. A Histological and Histomorphometric Study in the Rabbit Calvaria
2011
Background: Platelet rich plasma (PRP) has been proposed to be a useful adjunct to bone grafting. Purpose: The aim of the present study was to assess new bone formation in bone regeneration procedures using platelet rich plasma (PRP) alone or in combination with autogenous bone. Materials and Methods: Four surgically created, monocortical defects 5 mm in diameter in the calvariae of 15 New Zealand rabbits were grafted with a coagulum-filled control, PRP, particulated autogenous bone alone (A), or combined with PRP (A-PRP). Results: Mean platelet concentration of 1,761,930 ± 680,200/µl was achieved (5.30 ± 2.63 × fold of baseline). Animals were sacrificed 1, 2, and 4 weeks later. Histomorpho…
Grafted Rods: A Tilting Phase Transition
1996
A tilting phase transition is predicted for systems comprising rod like molecules which are irreversibly grafted to a flat surface, so that the non interacting rods are perpendicularly oriented. The transition is controlled by the grafting density $\rho$. It occurs as $\rho$ increases as a result of the interplay between two energies. Tilt is favoured by the van-der-Waals attraction between the rods. It is opposed by the bending elasticity of the grafting functionality. The role of temperature is discussed, and the tilting mechanism is compared to other tilting transitions reported in the literature.