scholarly journals Síntese e caracterização do compósito zircônia/alumina para aplicação em próteses

2020 ◽  
pp. 27-37
Author(s):  
Viviane S Gomide
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Particle Size ◽  
Biomedical Applications ◽  
Human Fibroblasts ◽  
Life Quality ◽  
Mechanical Resistance ◽  
Alumina Composite ◽  
Selection Of

The need to repair or reconstruct bone tissues drives the development to biomedical applications by providing better life quality for people who need to resort to the replacement of tissues. For the selection of the material to be used, it is necessary to evaluate some fundamental factors such as: mechanical resistance and biocompatibility. Often, only one material does not have all the desired properties, requiring the formation of composites in order to guarantee the appropriate characteristics. The present work presents the mechanical properties of a ceramic zirconia/alumina composite developed for application as prostheses; cytotoxicity in human fibroblasts was tested in vitro. Compressive strength, microhardness, fracture toughness and particle size measurements were also performed.

scholarly journals Characterization of Forcespun Polycaprolactone Fibers Infused with Bio-Based Hydroxyapatite for Biomedical Applications

2020 ◽  
Vol 2 (2) ◽  
pp. 23
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Biomedical Applications ◽  
Size Reduction ◽  
Biological Assessment ◽  
Fish Scales ◽  
Particle Size Reduction ◽  
Uniform Dispersion ◽  
Bead Mill

A novel Force spinning technique was used to fabricate microfibers from polycaprolactone (PCL) infused with bio-based hydroxyapatite (HA). The aim of this study is to analyze the thermo-mechanical properties of the developed fibers in addition to cell adhesion and proliferation analysis. The HA is synthesized from sundried raw fish scales of carpa family. The fish scales are calcinated at 800°C in a box furnace and are bead milled for one hour in a nano agitator bead mill for particle size reduction. Thus obtained nanoparticles are characterized using XRD, SEM, and TEM for particle size reduction, crystallinity, and structure. The PCL solution formed by dissolving 16 wt% of PCL in chloroform is magnetically stirred for 3 hrs at 170 rpm. The HA nanoparticles were infused in this solution by 1, 2, and 3 wt% and is stirred in a think mixer under vacuum for 7 mins for uniform dispersion of nanoparticles in the solution. The solution mixture is injected into the spinneret of force spinning apparatus. The PCL/HA fibers were collected at rotational aped 7000 rpm with a spin time of 10mins. The thermo-mechanical properties of the fibers were analyzed using tensile test, DSC, and DMA analyses. The biological assessment of the fibers is done using in vitro cell studies of the scaffolds that were cut from the fibers. These scaffolds can be further used for various biomedical applications such as sutures and controlled wound healing.

scholarly journals Development of nitazoxanide-loaded colon-targeted formulation for intestinal parasitic infections: centre composite design-based optimization and characterization

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Charu Bharti ◽  
Upendra Nagaich ◽  
Jaya Pandey ◽  
Suman Jain ◽  
Neha Jain
Keyword(s):  
Particle Size ◽  
Desirability Function ◽  
In Vitro Release ◽  
Entrapment Efficiency ◽  
In Vitro Drug Release ◽  
Release Studies ◽  
Percentage Yield ◽  
Vitro Release ◽  
Selection Of

Abstract Background The current investigation is focused on the development and characterization of Eudragit S100 coated nitazoxanide-loaded microbeads as colon-targeted system utilizing central composite design (CCD) and desirability function. The study initiated with the selection of a BCS class II drug nitazoxanide and its preformulation screening with excipients, selection of polymer and identification of concentration for CCD, selection of optimized formulation based on desirability function, and in vitro release studies in simulated gastric and colonic media and stability studies. A two-factor, three-level CCD was employed with two independent variables, i.e. X1 (chitosan % w/v) and X2 (sodium tripolyphosphate % w/v), and three dependent variables, i.e. Y1 (particle size in micrometres), Y2 (percentage yield) and Y3 (percent entrapment efficiency), were chosen. Additionally, surface morphology, mucoadhesion and in vitro drug release studies were also conducted. Result Chitosan concentration showing maximum entrapment and optimum particle size was selected to formulate chitosan beads. The polynomial equation and model graphs obtained from the Design-Expert were utilized to examine the effect of independent variables on responses. The effect of formulation composition was found to be significant (p ˂ 0.05). Based on the desirability function, the optimized formulation was found to have 910.14 μm ± 1.03 particle size, 91.84% ± 0.64 percentage yield and 84.75% ± 0.38 entrapment efficiency with a desirability of 0.961. Furthermore, the formulations were characterized for in vitro drug release in simulated colonic media (2% rat caecal content) and have shown a sustained release of ∼ 92% up to 24 h as compared to in vitro release in simulated gastric fluid. Conclusion The possibility of formulation in enhancing percentage yield and entrapment efficiency of nitazoxanide and the utilization of CCD helps to effectively integrate nitazoxanide microbeads into a potential pharmaceutical dosage form for sustained release.

scholarly journals Injectable non-leaching tissue-mimetic bottlebrush elastomers as an advanced platform for reconstructive surgery

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Erfan Dashtimoghadam ◽  
Farahnaz Fahimipour ◽  
Andrew N. Keith ◽  
Foad Vashahi ◽  
Pavel Popryadukhin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reconstructive Surgery ◽  
Biomedical Applications ◽  
The Body ◽  
Surrounding Tissue ◽  
Curing Time ◽  
Materials Used ◽  
Significant Health

AbstractCurrent materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.

Novel Baddeleyite-Based Zirconia Ceramics for Biomedical Applications

2017 ◽  
Vol 13 ◽  
pp. 9-14
Author(s):  
Alexander I. Tyurin ◽  
Andrey O. Zhigachev ◽  
Alexey V. Umrikhin ◽  
Vyacheslav V. Rodaev ◽  
Tatyana S. Pirozhkova
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tetragonal Phase ◽  
Biomedical Applications ◽  
Zirconia Ceramics ◽  
Engineering Ceramics ◽  
Synthesis Conditions ◽  
Microstructure And Mechanical Properties ◽  
First Time

For the first time nanostructured engineering ceramics were prepared from natural zirconia mineral (baddeleyite) with CaO as a tetragonal phase stabilizer. The effect of synthesis conditions on microstructure and mechanical properties of the baddeleyite-based ceramics is reported, furthermore, the effect of calcia content on hardness and fracture toughness is studied. Optimal calcia concentration and synthesis conditions are found, corresponding hardness and fracture toughness values are 10,8 GPa and 13,3 MPa×m1/2. The reported mechanical properties are comparable to those typically reported for yttria-stabilized engineering zirconia ceramics, prepared from chemically synthesized zirconia.

Formulation and Evaluation of Benidipine Nanosuspension

2021 ◽  
pp. 4111-4116
Author(s):  
Sejal Patel ◽  
Anita P. Patel
Keyword(s):  
Particle Size ◽  
Water Solubility ◽  
Polymer Concentration ◽  
Oral Route ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Scanning Calorimetry ◽  
23 Factorial Design ◽  
Selection Of

In the interest of administration of dosage form oral route is most desirable and preferred method. After oral administration to get maximum therapeutic effect, major challenge is their water solubility. Water insoluble drug indicate insufficient bioavailability as well dissolution resulting in fluctuating plasma level. Benidipine (BND) is poorly water soluble antihypertensive drug has lower bioavailability. To improve bioavailability of Benidipine HCL, BND nanosuspension was formulated using media milling technique. HPMC E5 was used to stabilize nanosuspension. The effect of different important process parameters e.g. selection of polymer concentration X1(1.25 mg), stirring time X2 (800 rpm), selection of zirconium beads size X3 (0.4mm) were investigated by 23 factorial design to accomplish desired particle size and saturation solubility. The optimized batch had 408 nm particle size Y1, and showed in-vitro dissolution Y2 95±0.26 % in 30 mins and Zeta potential was -19.6. Differential scanning calorimetry (DSC) and FT-IR analysis was done to confirm there was no interaction between drug and polymer.

scholarly journals Automatic Evaluation of the Mechanical Properties of Steels Maraging using Digital Image Processing Techniques

2020 ◽  
Author(s):  
Angélica Alves Viana ◽  
Savio Lopes Rabelo ◽  
José Daniel de Alencar Santos ◽  
Venceslau Xavier de Lima Filho ◽  
Douglas De Araújo Rodrigues ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Maraging Steel ◽  
Raw Material ◽  
High Fracture Toughness ◽  
Mechanical Resistance ◽  
High Fracture ◽  
Traditional System ◽  
Transformation Methods ◽  
Processing Techniques

Some strategic sectors of the economy require that the raw material of their machines and equipment have mechanical properties that satisfy their use. Maraging steel is a material of great concern since it is necessary to have a high mechanical resistance associated with high fracture toughness. The traditional tests to determine the fracture toughness of this material before use in applications are the Charpy and KIC tests. However, this process is characterized by being exhaustive and requiring specialized and trained professionals. Thus, to reverse this situation, this work proposes a new approach to determine the mechanical properties of maraging steel. For this, initially, the method removes any artifacts present in the image resulting from the mode of acquisition. In sequence, this works tested the method Extended Minimum Transformation (EMT) and mathematical morphology to find these markers of the regions of the dimples. Then, the Adaptive Thresholding, Optimal Global Thresholdusing the Otsu Method and Watershed transformation methods were used to segment the dimples. In the end, the diameter of the dimples and the toughness of the material were calculated. Tests are carried out and compared with the result obtained by specialists using the traditional system to evaluate the proposed approach. The results obtained were satisfactory for the application because the proposed approach presented speed and precision to the conventional methods.

scholarly journals Injectable Non-leaching Tissue-mimetic Bottlebrush Elastomers: A New Platform for Advancing Reconstructive Surgery

2020 ◽  
Author(s):  
Erfan Dashtimoghadam ◽  
Farahnaz Fahimipour ◽  
Andrew Keith ◽  
Foad Vashahi ◽  
Pavel Popryadukhin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reconstructive Surgery ◽  
Biomedical Applications ◽  
The Body ◽  
Surrounding Tissue ◽  
Curing Time ◽  
Materials Used ◽  
Significant Health

Abstract Current materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.

scholarly journals 3D-printable zwitterionic nano-composite hydrogel system for biomedical applications

2020 ◽  
Vol 11 ◽  
pp. 204173142096729
Author(s):  
Nathalie Sällström ◽  
Andrew Capel ◽  
Mark P Lewis ◽  
Daniel S Engstrøm ◽  
Simon Martin
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Culture Medium ◽  
Careful Selection ◽  
Nano Composite ◽  
Significant Difference ◽  
Nano Clay ◽  
Hydrogel Surface ◽  
Selection Of ◽  
Hydrogel System

Herein, the cytotoxicity of a novel zwitterionic sulfobetaine hydrogel system with a nano-clay crosslinker has been investigated. We demonstrate that careful selection of the composition of the system (monomer to Laponite content) allows the material to be formed into controlled shapes using an extrusion based additive manufacturing technique with the ability to tune the mechanical properties of the product. Moreover, the printed structures can support their own weight without requiring curing during printing which enables the use of a printing-then-curing approach. Cell culture experiments were conducted to evaluate the neural cytotoxicity of the developed hydrogel system. Cytotoxicity evaluations were conducted on three different conditions; a control condition, an indirect condition (where the culture medium used had been in contact with the hydrogel to investigate leaching) and a direct condition (cells growing directly on the hydrogel). The result showed no significant difference in cell viability between the different conditions and cells were also found to be growing on the hydrogel surface with extended neurites present.

In Vitro Three Dimensional Imaging of Human Carotid Atherosclerotic Plaques Using Ultrasonography

2011 ◽  
Author(s):  
Renate W. Boekhoven ◽  
Marcel C. M. Rutten ◽  
Marc R. H. M. van Sambeek ◽  
Frans N. van de Vosse
Keyword(s):  
Mechanical Properties ◽  
Carotid Artery ◽  
Carotid Endarterectomy ◽  
Early Stage ◽  
Three Dimensional ◽  
Atherosclerotic Plaques ◽  
Unstable Plaques ◽  
Human Carotid ◽  
Selection Of

Ruptured atherosclerotic plaques in the carotid artery are the main cause of stroke (70–80%). To prevent it, carotid endarterectomy is the procedure of choice in patients with a recent symptomatic 70–99% stenosis. Today, the selection of candidates is based on stenosis size only. However, endarterectomy is beneficial for only 1 out of 6 patients [1], the patients with unstable plaques (Fig. 1). Knowledge of mechanical properties of different components in the atherosclerotic arteries is important, because it will allow the identification of plaque stability at an early stage.

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