Search results for "Adhesive"

Force control and powder dispersibility of spray dried particles for inhalation

2009

This study aims towards a deeper understanding of the correlation between particle morphology, cohesion forces, and aerosol performance of spray dried powders for inhalation. Therefore, forces affecting cohesion and dispersion are consid- ered and some novel contact models are introduced to explain the improved powder dispersibility of corrugated particles. Particles with different degrees of corrugation are prepared by spray drying and characterized. Powder dispersibility is measured by positioning a dry powder inhaler in front of the laser diffraction device. The particle sizes of all powders are in the range of x50 ¼ 2.11 � 0.15 mm. The ratio of mass specific surface area Sm to volume sp…

The influence of the nature of the surface oxide on the adhesive fracture energy of aluminium-bonded joints as measured by T-peel tests

2008

Abstract Modification of aluminium alloy substrates microstructure and morphology by depositing new oxide layers on top of the metal surface has been investigated, with the aim of improving adhesion. The effect of treating the metal with boiling water or immersing it in a cerate bath has been studied by means of electron microscopy, contact angle measurements and peeling tests. The formation of pseudoboehmite layers or cerium conversion coatings both led to an increase in joint's adhesive fracture energy and more durable adhesive bonds with respect to joints obtained with “mechanically grinded only” substrates. Differences in the performance of the bonded joints has been discussed in terms …

Antibacterial and white spot lesions preventive effect of an orthodontic resin modified with silver-nanoparticles

2021

Background To evaluate the antibacterial property of a modified orthodontic resin with different concentrations of silver-nanoparticles (AgNPs), and quantify its preventive effect on the formation of white spot lesions (WSLs). Material and Methods An orthodontic resin (Transbond XT) was modified with four concentrations of AgNPs (1%, 0.5%, 0.1%, and 0.05%), the orthodontic resin without AgNPs was used as control. Polymerized resin discs (n=80) were submitted to Agar diffusion test on Petri dishes inoculated with Streptococcus mutans and Lactobacillus acidophilus. In addition, resin discs of each group (n=40) were placed in 96-well plates with bacterial suspensions to evaluate the colony-for…

Effect of an orthodontic resin modified with silver-nanoparticles on enamel color change

2021

Background: To evaluate the effect of an orthodontic resin modified with various concentrations of silver-nanoparticles (AgNPs) on enamel color. Material and Methods: Twenty lower premolars were collected and divided into four groups (n = 5) according to the concentration of AgNPs (0.05%, 0.1%, 0.5%, and 1% wt/wt). Additionally, a group bonded with a conventional resin was used as control (n=5). Previous to the bracket bonding, enamel color was measuring with a spectrophotometer. Specimens were stored for 6 months in deionized water. Brackets were debonded and color changes of enamel were calculated with the CIEDE 2000 formula (ΔE00). One-way ANOVA and Tukey test were used to assess the col…

2015

Patients suffering from chronic inflammatory diseases have an increased mortality risk resulting from cardiovascular disorders due to enhanced atherosclerotic and thrombotic events. Until now, it is not completely understood in which way an abnormal expression of pro-inflammatory mediators contributes to this elevated cardiovascular risk, but there is a need for new drugs that on the one hand suppress the expression of pro-inflammatory mediators and on the other hand inhibit arterial platelet adhesion. Thus, we analyzed the anti-inflammatory and anti-thrombotic capacity of the fungal metabolite Galiellalactone in atherosclerosis-prone apolipoprotein E-deficient mice. Treatment of the mice w…

Mucoadhesive Polymeric Films to Enhance Barbaloin Penetration Into Buccal Mucosa: a Novel Approach to Chemoprevention.

2018

Nowadays, chemoprevention by administering natural supplements is considered an attractive strategy to reverse, suppress, or prevent the evolution of premalignant oral lesions. In particular, Barbaloin exhibits anti-proliferative, anti-inflammatory, and anti-cancer properties, and it results useful in multi-therapy with classic chemotherapeutics. Therefore, in this work, mucoadhesive buccal films, as locoregional drug delivery system able to provide a targeted and efficient therapeutic delivery of Barbaloin, are proposed. Thus, Aloin extract-loaded Eudragit (R) RL100 or Eudragit (R) RS100-based buccal films were designed in order to obtain an easily self-administrable formulation capable of…

Innovative strategies to treat skin wounds with mangiferin: fabrication of transferosomes modified with glycols and mucin

2020

Aim: The moisturizing properties of glycerol, the penetration enhancing capability of propylene glycol and the bioadhesive properties of mucin were combined to improve the carrier capabilities of transfersomes and the efficacy of mangiferin in the treatment of skin lesions. Materials & methods: Mangiferin was incorporated in transfersomes and glycoltransfersomes, which were also modified with mucin. The physico–chemical features were assessed, along with the efficacy against oxidative stress and skin wounds in vitro and in vivo. Results: Glycoltransfersomes promoted the deposition of mangiferin in epidermis and dermis, protected fibroblasts from oxidative stress and stimulated their pr…

Biocompatibility, hemocompatibility and antimicrobial properties of xyloglucan-based hydrogel film for wound healing application.

2018

Crosslinked xyloglucan-poly(vinyl alcohol) based hydrogel films are interesting materials for wound healing applications. This work focuses on the hydrolytic degradation and consequent morphological modification of a XG-PVA film and on its interaction with cells, blood, bacteria. Biocompatibility of the film was assessed in vitro by investigating different aspects, such as cell viability, oxidative stress level, mitochondrial dysfunction and specific stress biomarkers. Partial adhesiveness was demonstrated by performing different attaching assays and phalloidin staining. Hemocompatibility of XG-PVA film after interaction with blood was evaluated by using a multi-parametric approach, includi…

Interfacial shear strength of flax fibers in thermoset resins evaluated via tensile tests of UD composites

2012

Abstract A method of interfacial shear strength evaluation, based on the length distribution of fibers pulled out from the tensile fracture surface of an oriented flax-reinforced composite, is applied to composites with vinyl ester and acrylated epoxidized soy oil resin matrices. Two approaches for characterizing the strength of fibers with modified Weibull distribution, fiber fragmentation tests and fiber tension tests, are compared in the analysis of pull-out data. Interfacial shear strength is found to increase by a few percent when loading rate is increased from 1.33% to 8%/min.

Evaluation of Ligno Boost™ softwood kraft lignin epoxidation as an approach for its application in cured epoxy resins

2018

Abstract In this study, modification of LignoBoost™ softwood kraft lignin with epichlorhydrin in water-organic solvents media was realized. Lignin-based epoxy resins were obtained by two ways: acetone extraction of glycidylated lignin or glycidylation of the acetone soluble lignin fraction. The effect of glycidylation regimes on the yields of acetone soluble fractions, their functional composition and physical-chemical characteristics was investigated using wet chemistry methods, FTIR spectroscopy, size exclusion chromatography (SEC) and differential scanning calorimetry (DSC). The positive effect of the biphasic phase transfer catalytic system – KOH/quaternary ammonium salt – on glycidylat…