scholarly journals Development of a 3D polyetheretherketone structure that mimics the cranial bone morphology for use in cranioplasty

2021 ◽  
Vol 10 (3) ◽  
pp. e29810313336
Author(s):  
Maria Dennise Medeiros Macedo ◽  
Claudio Orestes Britto Filho ◽  
Matheus Ferreira de Souza ◽  
Wladymyr Jefferson Bacalhau de Sousa ◽  
Thiago Caju Pedrosa ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Uniaxial Compression ◽  
3D Structure ◽  
Cranial Bone ◽  
Pore Morphology ◽  
Bone Morphology ◽  
Salt Leaching ◽  
Porous Compact ◽  
Compression Resistance ◽  
Common Situation

Cranioencephalic traumatism (TBI) is a common situation in trauma hospitals and has become responsible for high rates of mortality worldwide. When the victim of TBI is affected by injuries to the skullcap with a need for grafting, problems regarding the availability of suitable and affordable materials eventually happen. In this study, a 3D structure of Polyetheretherketone (PEEK) that mimics the cranial bone morphology for use in cranioplasty was developed. Samples of different formulations, in the form of round bars, were obtained through uniaxial compression, and porosity was controlled by the salt leaching technique. Then, the specimens were characterized in terms of pore morphology and distribution, surface roughness, compression resistance and cytotoxicity. Results exhibited high levels of similarity of the 3D strutures of PEEK to the natural human bone, which indicates the effectiveness of the proposed method in mimicking the morphology of the compact/porous/compact system of the skullcap (diploe).

The Study of Field Effect through Uniaxial Compression Experiment on Marine Recycled Concrete Specimen Based on DPDM Technique

2012 ◽  
Vol 446-449 ◽  
pp. 1735-1742
Author(s):  
Wen Bai Liu ◽  
Chao Shen ◽  
Xia Li ◽  
Hong Ming Jiang
Keyword(s):  
Uniaxial Compression ◽  
Field Effect ◽  
Strain Curve ◽  
Heterogeneous Material ◽  
Concrete Specimen ◽  
Middle Part ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Compression Resistance

Recycled concrete is a kind of composite heterogeneous material. Through the uniaxial compression experiment on recycled concrete specimen, the corresponding stress-strain curve is depicted with the major variables of replacement rate of recycled aggregate and time of corrosion by seawater, and the analysis of compression resistance capacity of recycled concrete sample is carried out by comparing common samples with those after the process of vacuum pumping. According to the results of comparison, the process of vacuum pumping can raise the strength of concrete by 9% to 22% and the lowering speed of compression resistance capacity rises as replacement rate of recycled aggregate goes up after the same corrosion period. The compression resistance capacity of the concrete specimen with replacement rate of 60% descends 50% to 80% faster than the sample with 30% of rate. DPDM technique is used to analyze deformation field, displacement field and strain field of concrete specimen during the process of uniaxial compression. As shown in the images from the experiment, the cracks develop from the bottom and both edges towards the middle part along the direction of loading until some of them run through the cube with the failure of the overall specimen while the stress reaches the peak, the displacement amount decreases from bottom to top and from both edges to center and the greatest strain concentration scatters around the bottom of the specimen while the strain of 62% appears around the peak stress of 33-36MPa. This paper puts forward constructive references and guidance for the application of recycled concrete in marine engineering on the basis of the study of field effect through uniaxial compression experiment based on DPDM technique.

Microscopic Dynamics of Water and Hydrocarbon in Shale-Kerogen Pores of Potentially Mixed Wettability

SPE Journal ◽  
2014 ◽  
Vol 20 (01) ◽  
pp. 112-124 ◽  
Author(s):  
Yinan Hu ◽  
Deepak Devegowda ◽  
Alberto Striolo ◽  
Anh Thi Van Phan ◽  
Tuan A. Ho ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Functional Groups ◽  
Hydraulic Fracture ◽  
Oil And Gas ◽  
Careful Consideration ◽  
Pore Morphology ◽  
Essential Information ◽  
Mixed Wettability ◽  
Slit Pore ◽  
Organic Pores

Summary Distribution of alkanes and water in organic pores of shale, referred to as kerogen, is essential information required for the estimation of shale-reservoir oil and gas in place, adsorption of hydrocarbon, and fate of hydraulic-fracture water. A practical modeling approach is presented for the proper description of the kerogen pore systems with different mixed wettability, surface roughness, tortuous paths, and material disorder. Three kerogen models—activated kerogen, kerogen free of activated sites, and graphite-slit pore—with proper surface-oxidized functional groups and high-temperature and pressure maturation are constructed by simulation. Distribution of octane and water in the organic pores of these models is predicted by molecular dynamics (MD) simulation. The results from our studies underscore the need for accurate characterization of kerogen pore systems in terms of the pore morphology, level of surface activation, and pore size. The improved kerogen models constructed to structurally resemble real organic materials have the potential to enable a better understanding of the placement, distribution, and trapping mechanisms of hydraulic-fracture water in shales. We demonstrate that depending on the maturity of the kerogen within organic-rich shales, organic pore systems may have mixed-wet characteristics and may create opportunities for water entrapment. The differences in the uptake of water are shown to be a function of the existence of oxygenated functional groups. In addition, the adsorption characteristics of alkanes in pores characterized by surface roughness are shown to be significantly different from those observed in the graphite-slit pore model. Our results indicate that careful consideration of the pore morphology is merited when estimating hydrocarbons in place with the Langmuir monolayer-adsorption theory.

scholarly journals Effect of pore morphology and surface roughness on wettability of porous titania films

2020 ◽  
Vol 7 (11) ◽  
pp. 115013
Author(s):  
Bangyun Xiong ◽  
Jingjing Li ◽  
Chunqing He ◽  
Xiuqin Tang ◽  
Zizhao Lv ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Pore Morphology ◽  
Porous Titania ◽  
Titania Films

Study on Layer Fabrication for 3D Structure of Photoreactive Polymer Using DLP Projector

2013 ◽  
Vol 465-466 ◽  
pp. 911-915
Author(s):  
Kamarudin Khairu ◽  
Mustaffa Ibrahim ◽  
S. Hassan ◽  
H. Hehsan ◽  
Ashari Kasmin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Light Intensity ◽  
Light Source ◽  
Exposure Time ◽  
3D Structure ◽  
Reactive Polymer ◽  
3D Microstructure ◽  
Microstructure Fabrication ◽  
Sudan I

This paper presents a research on 3D part fabrication from composition of photo initiator (Phenylbis (2,4,6-trimethylbenzoyl)), photo absorber (Sudan I) and 1, 6-Hexanediol polymer effect based on curing parameters. A DLP projector was used as energy light source which initiated the photo reactive polymer at three different light source distances with three different exposed time to evaluate photoreactive polymer solidification phenomena. The experiment results obtained shows that Sudan I composition, light intensity value and exposure time of the varied photo absorber give significant effect to layer thicknes, surface roughness and hardness value. These works also prove that photo absorber composition solution gave a different mechanical properties effect for 3D microstructure fabrication.

scholarly journals Cell Integration with Electrospun PMMA Nanofibers, Microfibers, Ribbons, and Films: A Microscopy Study

2019 ◽  
Vol 6 (2) ◽  
pp. 41 ◽  
Author(s):  
Daniel P. Ura ◽  
Joanna E. Karbowniczek ◽  
Piotr K. Szewczyk ◽  
Sara Metwally ◽  
Mateusz Kopyściański ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Fiber Diameter ◽  
3D Structure ◽  
Microscopy Study ◽  
Tissue Growth ◽  
Culture Study ◽  
Water Contact ◽  
Cell Culture Study

Tissue engineering requires properly selected geometry and surface properties of the scaffold, to promote in vitro tissue growth. In this study, we obtained three types of electrospun poly(methyl methacrylate) (PMMA) scaffolds—nanofibers, microfibers, and ribbons, as well as spin-coated films. Their morphology was imaged by scanning electron microscopy (SEM) and characterized by average surface roughness and water contact angle. PMMA films had a smooth surface with roughness, Ra below 0.3 µm and hydrophilic properties, whereas for the fibers and the ribbons, we observed increased hydrophobicity, with higher surface roughness and fiber diameter. For microfibers, we obtained the highest roughness of 7 µm, therefore, the contact angle was 140°. All PMMA samples were used for the in vitro cell culture study, to verify the cells integration with various designs of scaffolds. The detailed microscopy study revealed that higher surface roughness enhanced cells’ attachment and their filopodia length. The 3D structure of PMMA microfibers with an average fiber diameter above 3.5 µm, exhibited the most favorable geometry for cells’ ingrowth, whereas, for other structures we observed cells growth only on the surface. The study showed that electrospinning of various scaffolds geometry is able to control cells development that can be adjusted according to the tissue needs in the regeneration processes.

scholarly journals Analysis of different interface treatments between masonry of AAC blocks and reinforced concrete structure after uniaxial compression strength test

2021 ◽  
Vol 71 (343) ◽  
pp. e252
Author(s):  
D.S. Silva ◽  
E.G.P. Antunes
Keyword(s):  
Reinforced Concrete ◽  
Uniaxial Compression ◽  
Concrete Structure ◽  
Load Capacity ◽  
Maximum Load ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structure ◽  
Uniaxial Compression Strength ◽  
Compression Resistance ◽  
Interface Treatment

Autoclaved aerated concrete (AAC) masonry is widely used in civil construction but requires further investigation. Hence, this experimental study evaluated three types of interface treatment between the reinforced concrete structure and AAC masonry, in scale, after a uniaxial compression resistance test. The types of interface treatment considered are reinforcement with steel bars, with rough polymeric cementitious mortar, and without treatment. The maximum load capacity, displacements, and occurrence of cracks were analysed. The results showed that the maximum individual load capacity did not significantly differ among the examined groups. However, the analysis of the displacements and cracks showed that the group with steel reinforcement had the smallest displacements and largest cracks. This behaviour is owing to the greater solidarity of forces conferred by steel reinforcement.

scholarly journals Comparison of Scaffolds Fabricated via 3D Printing and Salt Leaching: In Vivo Imaging, Biodegradation, and Inflammation

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2210
Author(s):  
Doo Yeon Kwon ◽  
Joon Yeong Park ◽  
Bun Yeoul Lee ◽  
Moon Suk Kim
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Methylene Chloride ◽  
3D Structure ◽  
Fabrication Method ◽  
Scaffold Fabrication ◽  
Salt Leaching ◽  
Fused Deposition ◽  
Inflammation Reaction

In this work, we prepared fluorescently labeled poly(ε-caprolactone-ran-lactic acid) (PCLA-F) as a biomaterial to fabricate three-dimensional (3D) scaffolds via salt leaching and 3D printing. The salt-leached PCLA-F scaffold was fabricated using NaCl and methylene chloride, and it had an irregular, interconnected 3D structure. The printed PCLA-F scaffold was fabricated using a fused deposition modeling printer, and it had a layered, orthogonally oriented 3D structure. The printed scaffold fabrication method was clearly more efficient than the salt leaching method in terms of productivity and repeatability. In the in vivo fluorescence imaging of mice and gel permeation chromatography of scaffolds removed from rats, the salt-leached PCLA scaffolds showed slightly faster degradation than the printed PCLA scaffolds. In the inflammation reaction, the printed PCLA scaffolds induced a slightly stronger inflammation reaction due to the slower biodegradation. Collectively, we can conclude that in vivo biodegradability and inflammation of scaffolds were affected by the scaffold fabrication method.

Uniaxial compression tests of aluminium foams

2002 ◽  
Vol 216 (4) ◽  
pp. 633-636 ◽  
Author(s):  
F C Haag ◽  
A F Galio ◽  
L Schaeffer
Keyword(s):  
Uniaxial Compression ◽  
Aluminium Foam ◽  
Compression Tests ◽  
Lightweight Construction ◽  
Compression Resistance ◽  
Impact Absorption

Some cellular aluminium materials have been extensively developed and investigated in recent years. The potential for applying aluminium foams in lightweight construction is mainly based on the stiffness and impact absorption. Because of these characteristics, this work is based mainly on the uniaxial compression resistance of aluminium foam. The aluminium foam was formed with three different compaction presses to verify the influence on density and, subsequently, crushing resistance.

scholarly journals Viable Mice with Compound Mutations in the Wnt/Dvl Pathway Antagonists nkd1 and nkd2

2007 ◽  
Vol 27 (12) ◽  
pp. 4454-4464 ◽  
Author(s):  
Shu Zhang ◽  
Tolga Çagatay ◽  
Manami Amanai ◽  
Mei Zhang ◽  
Janine Kline ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Embryonic Development ◽  
Wnt Signaling ◽  
Knockout Mice ◽  
Fruit Fly ◽  
Cranial Bone ◽  
Bone Morphology ◽  
Intracellular Protein ◽  
Double Knockout ◽  
Physiological Homeostasis

ABSTRACT Gradients of Wnt/β-catenin signaling coordinate development and physiological homeostasis in metazoan animals. Proper embryonic development of the fruit fly Drosophila melanogaster requires the Naked cuticle (Nkd) protein to attenuate a gradient of Wnt/β-catenin signaling across each segmental anlage. Nkd inhibits Wnt signaling by binding the intracellular protein Dishevelled (Dsh). Mice and humans have two nkd homologs, nkd1 and nkd2, whose encoded proteins can bind Dsh homologs (the Dvl proteins) and inhibit Wnt signaling. To determine whether nkd genes are necessary for murine development, we replaced nkd exons that encode Dvl-binding sequences with IRES-lacZ/neomycin cassettes. Mutants homozygous for each nkd lacZ allele are viable with slightly reduced mean litter sizes. Surprisingly, double-knockout mice are viable, with subtle alterations in cranial bone morphology that are reminiscent of mutation in another Wnt/β-catenin antagonist, axin2. Our data show that nkd function in the mouse is dispensable for embryonic development.

Sign in / Sign up

Export Citation Format

Share Document