Search results for "Materials Testing"
showing 10 items of 254 documents
Partially Quarternized Amino Functional Poly(methacrylate) Terpolymers: Versatile Drug Permeability Modifiers
2011
Partially quarternized poly(methacrylate) terpolymers (Q-BBMCs) have been synthesized, based on the basic butylated methacrylate copolymer (BBMC/EUDRAGIT E), an excipient approved by the Food and Drug Administration (FDA) and to date mainly applied for tablet coatings. Via straightforward polymer modification reactions, a series of Q-BBMCs with quarternization degrees of 22%, 42%, and 65% has been prepared. Apical to basolateral transport across Caco-2 cell monolayers was investigated, employing the paracellular transported compounds trospium and mannitol. At pH 6.5 quarternization resulted in increased permeation enhancement up to 2.8-fold compared to BBMC, that is, up to 7.3-fold compared…
Fluorescent Core/Shell Nanoparticles for Specific Cell‐Nucleus Staining
2008
The highly fluorescent perylene-3,4,9,10-tetracarboxdiimide (PDI) chromophore is a popular dye and pigment because of its excellent chemical, thermal, and photochemical stability. Due to these outstanding properties, there have been several successful applications of PDI chromophores in various fields. Water-soluble and fluorescent PDI dyes have been used in biological applications such as the in vitro staining of cells and proteins. The combination of water solubility and high fluorescence quantum yield still represents a challenging goal since PDI dyes have a strong tendency to form aggregates in aqueous solution even at very low concentrations. Water solubility and high fluorescence quan…
Attachment of Marine Sponge Cells of Hymeniacidon perleve on Microcarriers
2003
Toward the development of an in vitro cultivation of marine sponge cells for sustainable production of bioactive metabolites, the attachment characteristics of marine sponge cells of Hymeniacidon perleve on three types of microcarriers, Hillex, Cytodex 3, and glass beads, were studied. Mixed cell population and enriched cell fractions of specific cell types by Ficoll gradient centrifugation (6%/8%/15%/20%) were also assessed. Cell attachment ratio (defined as the ratio of cells attached on microcarrier to the total number of cells in the culture) on glass beads is much higher than that on Cytodex 3 and Hillex for both mixed cell population and cell fraction at Ficoll 15-20% interface. The h…
The effect of dentine pre-treatment using bioglass and/or polyacrylic acid on the interfacial characteristics of resin-modified glass ionomer cements.
2018
Objective To evaluate the effect of load-cycle aging and/or 6 months artificial saliva (AS) storage on bond durability and interfacial ultramorphology of resin-modified glass ionomer cement (RMGIC) applied to dentine air-abraded using Bioglass 45S5 (BAG) with/without polyacrylic acid (PAA) conditioning.Methods RMGIC (Ionolux, VOCO) was applied onto human dentine specimens prepared with silicon-carbide abrasive paper or air-abraded with BAG with or without the use of PAA conditioning. Half of bonded-teeth were submitted to load cycling (150,000 cycles) and half immersed in deionised water for 24 h. They were cut into matchsticks and submitted immediately to microtensile bond strength (μTBS) …
Cytotoxicity and induction of DNA double-strand breaks by components leached from dental composites in primary human gingival fibroblasts
2012
Abstract Introduction The public interest steadily increases in the biological adverse effects caused by components released from resin-based dental restorations. Objective In this study, the cytotoxicity and the genotoxicity were investigated of following released components from dental resin restorations in human gingival fibroblasts (HGF): tetraethyleneglycol dimethacrylate (TEEGDMA), neopentylglycol dimethacrylate (Neopen), diphenyliodoniumchloride (DPIC), triphenyl-stibane (TPSB) and triphenylphosphane (TPP). Methods XTT based cell viability assay was used for cytotoxicity screening of substances. γ-H2AX assay was used for genotoxicity screening. In the γ-H2AX assay, HGFs were exposed …
Influences of heat seal lacquer thickness on the quality of blister packages.
2011
A sealability of aluminium lidding foils against formable polymer materials of blister packages is usually achieved by a coating of aluminium with certain grammages of heat seal lacquers. To investigate influences of their thickness on quality of blister packages, lidding foils with different grammages of two lacquer types were manufactured. Sealing experiments (variation of temperature, pressure and sealing time) were performed. Sealed seam strengths were determined with mechanical tensile tests, tightness of cold form blisters were analysed by means of helium leakage tests. Time-dependent moisture uptake of stored blisters was monitored with micro-gas chromatography. By means of a simple …
The Evaluation of Four Electronic Apex Locators in Teeth with Simulated Horizontal Oblique Root Fractures
2008
The accuracy of four electronic apex locators (EALs) to locate the apical limit in teeth with simulated horizontal oblique root fractures was investigated. A horizontal oblique incomplete root fracture was simulated on 20 freshly extracted maxillary anterior teeth by means of a notch made on the vestibular root plane 8 mm from the anatomic apex. The EALs investigated were the ProPex (Dentsply Maillefer, Ballaigues, Switzerland), the NovApex (Forum Technologies, Rishon Le-Zion, Israel), the Root ZX (J. Morita Corp, Kyoto, Japan), and the Elements Apex Locator (SybronEndo, Orange CA). The electronic measurements were compared with the real "working length." The accuracy obtained was of 80% (n…
The Influence of Friction on Design of the Type of Bracket and Its Relation to OHRQoL in Patients Who Use Multi-Bracket Appliances: A Randomized Clin…
2021
Background and objectives: The aim of this study was to evaluate the influence of friction on design of the type of bracket, patients’ perception of pain and the impact on their oral health-related quality of life. Materials and Methods: A randomized clinical trial was carried out with 90 patients (62.2% women and 37.8% men) with three kinds of fixed multi-bracket appliances: Conventional (GC), fixed multi-bracket low friction (GS) and self-ligating (GA). The VAS (Visual Analogue Scale) was used to determine pain during the first seven days of treatment at different points in time. The patients were also given the OHIP-14 (Oral Health Impact Profile) questionnaire to analyse their oral heal…
Biologic response of inguinal hernia prosthetics: a comparative study of conventional static meshes versus 3D dynamic implants.
2015
Despite improvements in prosthetics and surgical techniques, the rate of complications following inguinal hernia repair remains high. Among these, discomfort and chronic pain have become a source of increasing concern among surgeons. Poor quality of tissue ingrowth, such as thin scar plates or shrinking scars-typical results with conventional static implants and plugs-may contribute to these adverse events. Recently, a new type of 3D dynamically responsive implant was introduced to the market. This device, designed to be placed fixation-free, seems to induce ingrowth of viable and structured tissue instead of regressive fibrotic scarring. To elucidate the differences in biologic response be…
Influence of Riboflavin Targeting on Tumor Accumulation and Internalization of Peptostar Based Drug Delivery Systems.
2020
Riboflavin carrier protein (RCP) and riboflavin transporters (RFVTs) have been reported to be highly overexpressed in various cancer cells. Hence, targeting RCP and RFVTs using riboflavin may enhance tumor accumulation and internalization of drug delivery systems. To test this hypothesis, butyl-based 3-arm peptostar polymers were synthesized consisting of a lysine core (10 units per arm) and a sarcosine shell (100 units per arm). The end groups of the arms and the core were successfully modified with riboflavin and the Cy-5.5 fluorescent dye, respectively. While in phosphate buffered saline the functionalized peptostars showed a bimodal behavior and formed supramolecular structures over tim…