Search results for "34"
showing 10 items of 1830 documents
Composite Coatings of Chitosan and Silver Nanoparticles Obtained by Galvanic Deposition for Orthopedic Implants
2022
In this work, composite coatings of chitosan and silver nanoparticles were presented as an antibacterial coating for orthopedic implants. Coatings were deposited on AISI 304L using the galvanic deposition method. In galvanic deposition, the difference of the electrochemical redox potential between two metals (the substrate and a sacrificial anode) has the pivotal role in the process. In the coupling of these two metals a spontaneous redox reaction occurs and thus no external power supply is necessary. Using this process, a uniform deposition on the exposed area and a good adherence of the composite coating on the metallic substrate were achieved. Physical-chemical characterizations were car…
Hydroxyapatite/Chitosan/Collagen coatings through galvanic coupling
In this work, the attention was focused on Hydroxyapatite/ Chitosan/Collagen composite as biocoatings for application in orthopaedic devices. Hydroxyapatite was selected for its osteoconductivity due to its chemical structure similar to bones. Collagen has the same function since 90-95% of bone matrix is constituted of collagen fibers. Furthermore, chitosan are largely used yet in medical field (e.g. antibacterial agent or drug deliver) and in this work were used to create a synergic interaction with hydroxyapatite and collagen to increase the strength and bioactivity of coating. Coatings were fabricated by galvanic deposition process that has different advantages an it does not require ext…
Deposition and characterization of Hydroxyapatite-Chitosan coatings on 304 SS for biomedical devices
2019
During the last years biomaterials have been largely investigated in order to perform and improve biomedical devices. As regards orthopedic field, the most common equipment used (such as implants, bone grafts or screws) are constituted by metallic materials (steel and titanium alloys), characterized by low/medium resistance to corrosion and low osteointegration ability. Furthermore, these factors could produce local inflammations of the tissues surrounding the implants, increasing kinetics of corrosion phenomena. Scientific community has focused the attention on biocoatings interposed between metal and aggressive environment in order to inhibit corrosion. Furthermore, these coatings are abl…
Physical and biological properties of electrospun poly(d,l‐lactide)/nanoclay and poly(d,l‐lactide)/nanosilica nanofibrous scaffold for bone tissue en…
2021
Abstract Electrospun scaffolds exhibiting high physical performances with the ability to support cell attachment and proliferation are attracting more and more scientific interest for tissue engineering applications. The inclusion of inorganic nanoparticles such as nanosilica and nanoclay into electrospun biopolymeric matrices can meet these challenging requirements. The silica and clay incorporation into polymeric nanofibers has been reported to enhance and improve the mechanical properties as well as the osteogenic properties of the scaffolds. In this work, for the first time, the physical and biological properties of polylactic acid (PLA) electrospun mats filled with different concentrat…
Galvanic Deposition of Calcium Phosphate/Bioglass Composite Coating on AISI 316L
2023
Calcium phosphate/Bioglass composite coatings on AISI 316L were investigated with regard to their potential role as a beneficial coating for orthopedic implants. These coatings were realized by the galvanic co-deposition of calcium phosphate compounds and Bioglass particles. A different amount of Bioglass 45S5 was used to study its effect on the performance of the composite coatings. The morphology and chemical composition of the coatings were investigated before and after their aging in simulated body fluid. The coatings uniformly covered the AISI 316L substrate and consisted of a brushite and hydroxyapatite mixture. Both phases were detected using X-ray diffraction and Raman spectroscopy.…
PREPARATION AND CHARACTERIZATION OF POLYLACTIC ACID/SILICA AND POLYLACTIC ACID/CLAYS BIONANOCOMPOSITE ELECTROSPUN SYSTEMS
2019
Introduction Electrospinning is a versatile process technology for the production of fibers ranging from nano- to micro-scale. In order to develop high performance electrospun systems, the use of nanofillers is achieving more and more interest. In this context, silica (Si) and clays (Cl) are often used as fillers due to the possibility to combine the advantages of polymeric materials, such as light weight and flexibility, and inorganic materials, such as high mechanical strength, heat stability, and chemical stability. In this work, the morphology of PLA/Si and PLA/Cl were evaluated on two different weight ratios: 99/1 and 95/5 wt/wt. Material and Methods The nanoparticles were added to a s…
Blood Vessel Detection Algorithm for Tissue Engineering and Quantitative Histology.
2021
AbstractImmunohistochemistry for vascular network analysis plays a fundamental role in basic science, translational research and clinical practice. However, identifying vascularization in histological tissue images is time consuming and markedly depends on the operator’s experience. In this study, we present “blood vessel detection—BVD”, an automatic algorithm for quantitative analysis of blood vessels in immunohistochemical images. BVD is based on extraction and analysis of low-level image features and spatial filtering techniques, which do not require a training phase. BVD algorithm performance was comparatively evaluated on histological sections from three different in vivo experiments. …
Disturbing Weight Cutting Behaviors in Young Combat Sports Athletes: A Cause for Concern
2022
Problematic weight cutting behaviors in combat sports have been addressed in the scientific literature since the 1930s (1). Indeed, given the available evidence it may be the case that making weight/weight cycling [i.e., rapid weight loss (RWL) prior to weigh-in followed by rapid weight gain prior to competition] has been practiced in combat sports since weight divisions have been introduced. These practices have led to several fatalities (2), which occurred as a consequence of making weight rather than any sports-related injury. Unfortunately, RWL-related deaths still persist into recent times (3). Existing literature has detailed patterns of weight cycling (e.g., methods, magnitudes, freq…
Parental Stress and Parental Ratings of Behavioral Problems of Enuretic Children.
2019
Background: Primary monosymptomatic nocturnal enuresis (PMNE) may have a stressful impact on the everyday life of children and parents, and it may represent a cumulative stress factor increasing feelings of "learned helplessness." Methods: The current study investigated parental stress in a group of parents (n = 330) of children affected by PMNE, compared to a group of parents (n = 330) of typical developing children (TDC). In addition, the study evaluated whether parents of PMNE children experience more emotional, social, and behavioral problems in their children, compared to parents of TDC. Finally, the study correlated frequency of enuresis with stress values and Child Behavior Checklist…
AN APPLICATION OF A FIXED POINT THEOREM FOR NONEXPANSIVE OPERATORS
2014
Abstract. In this note, we present an application of a recent xed point theorem by Ricceri to a two-point boundary value problem. KeyWords and Phrases: Fixed point, nonexpansive operator, two-point boundary value problem. 2010 Mathematics Subject Classi cation: 34K10, 47H09, 47H10.