Search results for " release"
showing 10 items of 535 documents
Fatigue Design of Cruciform Joints including V-notch Effect at the Weld Toe
2014
Abstract The present paper proposes a new and more accurate fatigue life prediction model for fillet welded joints in steel subjected to constant amplitude loading. With the traditional fracture mechanics approach, the greatest difficulty when computing the fatigue life of a welded detail is to determine the initial crack size a0. The classical way to determine the stress intensity factor K (SIF) is by using the following formula Where σ is the applied stress, a is the crack size and g(a/T) the geometrical correction factor which has been determined by Gurney function or similar solutions. This approach is not accurate for short crack because of the singular V-notch behaviour close to the c…
Development of an lbuprofen-Releasing Biodegradable PLA/PGA Electrospun Scaffold for Tissue Regeneration
2009
Our aim was to develop a biodegradable fibrous dressing to act as a tissue guide for in situ wound repair while releasing Ibuprofen to reduce inflammation in wounds and reduce pain for patients on dressing changes. Dissolving the acid form of Ibuprofen (from 1% to 10% by weight) in the same solvent as 75% polylactide, 25% polyglycolide (PLGA) polymers gave uniformly loaded electrospun fibers which gave rapid release of drug within the first 8 h and then slower release over several days. Scaffolds with 10% Ibuprofen degraded within 6 days. The Ibuprofen released from these scaffolds significantly reduced the response of fibroblasts to major pro-inflammatory stimulators. Fibroblast attachment…
Relation between structural and release properties in a polysaccharide gel system.
2007
Abstract The potential utility of κ-carrageenan gels for preparing drug release devices is here shown. Structural properties of κ-carrageenan gels prepared with different salt composition and containing Ketoprofen sodium salt, as model drug, have been evaluated with static light scattering and rheological measurements. These properties have been correlated with release profiles in vitro at pH 5.5. Release properties from gelled matrices have been compared with those obtained by two commercial products containing the same drug. Results show that: i) in this system it is possible to easily control the gel texture by using different cationic concentration; ii) the kinetics of drug release by κ…
Near-Infrared, Light-Triggered, On-Demand Antiinflammatories and Antibiotics Release by Graphene Oxide/Elecrospun PCL Patch for Wound Healing
2019
Very recently, significant attention has been focused on the adsorption and cell adhesion properties of graphene oxide (GO), because it is expected to allow high drug loading and controlled drug release, as well as the promotion of cell adhesion and proliferation. This is particularly interesting in the promotion of wound healing, where antibiotics and anti-inflammatories should be locally released for a prolonged time to allow fibroblast proliferation. Here, we designed an implantable patch consisting of poly(caprolactone) electrospun covered with GO, henceforth named GO&ndash
Decreased release of histamine and sulfidoleukotrienes by human peripheral blood leukocytes after wasp venom immunotherapy is partially due to induct…
1999
Abstract Background: Recent studies provide evidence that venom immunotherapy (VIT) alters the pattern of cytokine production by inducing an allergen-specific T-cell shift in cytokine expression from T H2 (IL-4, IL-5) to T H1 (IFN-γ) cytokines and also inducing the production of IL-10. Objective: This study was carried out to analyze whether these changes in cytokine production of T cells already observed 1 week after the initiation of VIT in subjects with wasp venom allergy also influence the reactivity of effector cells, such as mast cells and basophils. Methods: All subjects included in this study had a history of severe systemic allergic reactions to wasp stings and positive skin test r…
Adjuvant effects of aluminium hydroxide-adsorbed allergens and allergoids – differences in vivo and in vitro
2014
Summary Allergen-specific immunotherapy (SIT) is a clinically effective therapy for immunoglobulin (Ig)E-mediated allergic diseases. To reduce the risk of IgE-mediated side effects, chemically modified allergoids have been introduced. Furthermore, adsorbance of allergens to aluminium hydroxide (alum) is widely used to enhance the immune response. The mechanisms behind the adjuvant effect of alum are still not completely understood. In the present study we analysed the effects of alum-adsorbed allergens and allergoids on their immunogenicity in vitro and in vivo and their ability to activate basophils of allergic donors. Human monocyte derived dendritic cells (DC) were incubated with native …
Relationships between sodium mobility, in-mouth salt and aroma release, and flavour perception : application to model cheeses
2012
The aim of this work is to understand the effects of changes in the composition of model cheeses on mobility, release and perception of flavor molecules (salt, aroma compounds). Six flavoured model cheeses were formulated (3 lipid/protein (L/P) ratios and 2 salt contents). The microstructure and the rheological properties of the model cheeses were characterized respectively by confocal microscopy and by uniaxial compression test. The mobility of sodium ions was analyzed by 23Na NMR. The kinetics of sodium release was followed in water and then in saliva during consumption of the model cheeses. The retronasal release of aroma compounds was followed by nose-space APCI-MS, simultaneously with …
Relationships between sodium mobility, in-mouth salt and aroma release, and flavour perception : application to model cheeses
2012
The aim of this work is to understand the effects of changes in the composition of model cheeses on mobility, release and perception of flavor molecules (salt, aroma compounds). Six flavoured model cheeses were formulated (3 lipid/protein (L/P) ratios and 2 salt contents). The microstructure and the rheological properties of the model cheeses were characterized respectively by confocal microscopy and by uniaxial compression test. The mobility of sodium ions was analyzed by 23Na NMR. The kinetics of sodium release was followed in water and then in saliva during consumption of the model cheeses. The retronasal release of aroma compounds was followed by nose-space APCI-MS, simultaneously with …
Mesocarnivore community structuring in the presence of Africa's apex predator
2021
This work was supported by the Peace Parks Foundation; G.C.S. was funded by a doctoral grant from Fundacão para a Ciência e a Tecnologia (FCT: PD/BD/114037/2015); L.H.S. was supported by the National Research Foundation, South Africa (UID: 107099 and 115040) and by the African Institute for Conservation Ecology. Apex predator reintroductions have proliferated across southern Africa, yet their ecological effects and proposed umbrella benefits of associated management lack empirical evaluations. Despite a rich theory on top-down ecosystem regulation via mesopredator suppression, a knowledge gap exists relating to the influence of lions (Panthera leo) over Africa's diverse mesocarnivore (less …
Chitosomes loaded with cranberry proanthocyanidins attenuate the bacterial lipopolysaccharide-induced expression of iNOS and COX-2 in raw 264.7 macro…
2009
Chitosan binds to negatively charged soy lecithin liposomes by an electrostatic interaction driven by its positively charged amino group. This interaction allows stable covered vesicles (chitosomes) to be developed as a suitable targeted carrier and controlled release system. This study investigated the effect of chitosomes on the activation of cranberry proanthocyanidins (PAC) in Raw 264.7 macrophages. Chitosomes were characterized according to size, zeta potential, PAC-loading, and release properties. Results showed an increase in the net positive charge and size of the liposomes as the concentration of chitosan was increased, suggesting an effective covering of the vesicles by means of e…