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Particulate Form (particulate + form)

Distribution by Scientific Domains
Medical Sciences75%

Selected Abstracts

Materials in particulate form for tissue engineering.

JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 2 2007

Abstract Materials in particulate form have been the subjects of intensive research in view of their use as drug delivery systems. While within this application there are still issues to be addressed, these systems are now being regarded as having a great potential for tissue engineering applications. Bone repair is a very demanding task, due to the specific characteristics of skeletal tissues, and the design of scaffolds for bone tissue engineering presents several difficulties. Materials in particulate form are now seen as a means of achieving higher control over parameters such as porosity, pore size, surface area and the mechanical properties of the scaffold. These materials also have the potential to incorporate biologically active molecules for release and to serve as carriers for cells. It is believed that the combination of these features would create a more efficient approach towards regeneration. This review focuses on the application of materials in particulate form for bone tissue engineering. A brief overview of bone biology and the healing process is also provided in order to place the application in its broader context. An original compilation of molecules with a documented role in bone tissue biology is listed, as they have the potential to be used in bone tissue engineering strategies. To sum up this review, examples of works addressing the above aspects are presented. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Materials in particulate form for tissue engineering.

JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 1 2007

Abstract For biomedical applications, materials small in size are growing in importance. In an era where ,nano' is the new trend, micro- and nano-materials are in the forefront of developments. Materials in the particulate form aim to designate systems with a reduced size, such as micro- and nanoparticles. These systems can be produced starting from a diversity of materials, of which polymers are the most used. Similarly, a multitude of methods are used to produce particulate systems, and both materials and methods are critically reviewed here. Among the varied applications that materials in the particulate form can have, drug delivery systems are probably the most prominent, as these have been in the forefront of interest for biomedical applications. The basic concepts pertaining to drug delivery are summarized, and the role of polymers as drug delivery systems conclude this review. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Herstellung und Eigenschaften eines neuen Leichtbetons: Aerogelbeton

BETON- UND STAHLBETONBAU, Issue 4 2008
Lorenz Ratke Prof. Dr.-Ing.
Die Dispergierung von superhydrophobem Aerogelgranulat in konventionelle Zement- oder Betonmischungen erzeugt einen Leichtbeton mit außergewöhnlichen Eigenschaften: gute Wärmedämmung, schallisolierend, Brandschutz der Klasse F120 und besser, bewehrbar und leicht mechanisch zu bearbeiten. Der Aufsatz beschreibt die Herstellung und einige Eigenschaften dieses neuartigen Baustoffs. Fabrication and Properties of a New Light Weight Concrete: Aerogel Concrete The distribution of super hydrophobic aerogel in particulate form into conventional cement or concrete mixtures produces a light weight concrete with extraordinary properties: good heat and sound insulation, fire protection of the class F120 and better, armorable und easy workable. The paper describes the fabrication and some properties of this new construction material. [source]

Separation of Pure and Immunoreactive Virus-Like Particles Using Gel Filtration Chromatography Following Immobilized Metal Ion Affinity Chromatography

BIOTECHNOLOGY PROGRESS, Issue 2 2001
Yu-Shen Cheng
A purification process was developed to obtain highly pure rVP2H particles, formed by a structural protein (VP2) of the infectious bursal disease virus (IBDV) with six additional histidine residues at its C-terminus. The ultimate goal was the development of an efficient subunit vaccine against IBDV infection. The particles within the infected High-Five (Hi-5) cell lysates were partially purified by employing immobilized metal ion (Ni2+) affinity chromatography (IMAC). The initial step could recover approximately 85% of immunoreactive rVP2H proteins but failed to separate the rVP2H particles from the free rVP2H proteins or its degraded products. To separate the particulate form from the free form of rVP2H, an additional step was added, which used either gel filtration chromatography or CsCl density gradient ultracentrifugation. Both were able to produce extremely pure rVP2H particles with a buoyant density close to 1.27 g/cm3. However, the former method can process a larger sample volume than does the latter. By integrating IMAC and gel filtration chromatography, 1 mg of extremely pure rVP2H particles was routinely obtained from a 500 mL Hi-5 cell culture broth. The separation of the particulate form from the free form of rVP2H proteins exposes their respective immunogenicity to induce the virus-neutralizing antibodies and the ability to protect chickens from IBDV infection. Additionally, the abundant quantities of pure rVP2H particles coupled with their uniform dimensions facilitates an understanding of higher order structure of the immunogenic particles and can therefore result in improved vaccines against the virus. [source]

Cutting Torque Measurements in Conjunction with Implant Placement in Grafted and Nongrafted Maxillas as an Objective Evaluation of Bone Density: A Possible Method for Identifying Early Implant Failures?

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2004
Björn Johansson DDS
ABSTRACT Background: Bone grafts are frequently used to enable the placement of dental implants in atrophied jaws. The biomechanical properties of bone grafts used in one- or two-stage implant procedures (in comparison with the use of nongrafted bone) are not well known. Purpose: The purpose of this study was (1) to measure cutting torques during the placement of self-tapping dental implants in nongrafted bone and in bone grafts, either as blocks or in a milled particulate form, in patients undergoing implant treatment in an edentulous maxilla and (2) to identify implants with reduced initial stability and to correlate these findings with a clinical classification of jawbone quality. Materials and Methods: The study included 40 consecutive patients with edentulous maxillas, 27 of whom were subjected to bone grafting prior to or in conjunction with implant placement (grafting group) and 13 of whom received implants without grafting (nongrafted group). Grafted bone from the iliac crest bone was used (1) as onlay blocks, (2) as maxillary sinus inlay blocks, or (3) in particulate form in the maxillary sinus. Implants were placed after 6 to 7 months of healing, except in the maxillary sinus inlay blocks, where implants were placed simultaneously. Cutting torque values were obtained from 113 grafted implant sites and from 109 nongrafted implant sites. Results: Significantly lower cutting torque values were assessed in grafted regions than in nongrafted regions, irrespective of grafting technique. Lower values were also seen for implants placed in block grafts after 6 months when compared to other grafting techniques used. The cutting torque values revealed an inverse linear relation to the Lekholm and Zarb bone quality index. Conclusion: The cutting torque values correlated well with the Lekholm and Zarb index of bone quality. Significantly lower cutting torque values were seen in grafted bone than in nongrafted bone. [source]