scholarly journals Rheological study on 3D printability of alginate hydrogel and effect of graphene oxide

2016 ◽  
Vol 2 (2) ◽  
Author(s):  
Huijun Li ◽  
Sijun Liu ◽  
Li Lin
Keyword(s):  
Graphene Oxide ◽  
3D Printing ◽  
Rheological Properties ◽  
Three Dimensional ◽  
Model Material ◽  
Alginate Hydrogel ◽  
New Approach ◽  
Shear Rates ◽  
Selection Of

In recent years, hydrogels have been used as important biomaterials for 3D printing of three dimensional tis-sues or organs. The key issue for printing a successful scaffold is the selection of a material with a good printability. Rheological properties of hydrogels are believed to pay an important role in 3D printability. However the relations be-tween rheological properties of hydrogels and 3D printability have not been extensively studied. In this study, algi-nate-based hydrogels were prepared as a model material for an extrusion-based printer and graphene oxide was added to modify the rheological properties and 3D printability of the hydrogels. Rheological studies were performed for the hy-drogel samples with different formulas. The range of shear rates that the hydrogels suffered during the printing process was deduced. This range of shear rates helped us to select a proper shear rate to investigate the thixotropic properties of the hydrogels. Furthermore, we also defined some measureable parameters to describe and discuss the quality of 3D printing. The present study shows a new approach to analysis of 3D printability of a hydrogel and also provides some suggestion for 3D printing of 3D scaffolds.

scholarly journals 3D Printing of Thermo-Sensitive Drugs

Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1524
Author(s):  
Sadikalmahdi Abdella ◽  
Souha H. Youssef ◽  
Franklin Afinjuomo ◽  
Yunmei Song ◽  
Paris Fouladian ◽  
...  
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
Fused Deposition Modelling ◽  
Future Directions ◽  
Digital Light Processing ◽  
Fused Deposition ◽  
Printing Technique ◽  
3D Printed ◽  
Semi Solid ◽  
Selection Of

Three-dimensional (3D) printing is among the rapidly evolving technologies with applications in many sectors. The pharmaceutical industry is no exception, and the approval of the first 3D-printed tablet (Spiratam®) marked a revolution in the field. Several studies reported the fabrication of different dosage forms using a range of 3D printing techniques. Thermosensitive drugs compose a considerable segment of available medications in the market requiring strict temperature control during processing to ensure their efficacy and safety. Heating involved in some of the 3D printing technologies raises concerns regarding the feasibility of the techniques for printing thermolabile drugs. Studies reported that semi-solid extrusion (SSE) is the commonly used printing technique to fabricate thermosensitive drugs. Digital light processing (DLP), binder jetting (BJ), and stereolithography (SLA) can also be used for the fabrication of thermosensitive drugs as they do not involve heating elements. Nonetheless, degradation of some drugs by light source used in the techniques was reported. Interestingly, fused deposition modelling (FDM) coupled with filling techniques offered protection against thermal degradation. Concepts such as selection of low melting point polymers, adjustment of printing parameters, and coupling of more than one printing technique were exploited in printing thermosensitive drugs. This systematic review presents challenges, 3DP procedures, and future directions of 3D printing of thermo-sensitive formulations.

Neighborhood Evaluation in Recommender Systems Using the Realization Based Entropy Approach

2014 ◽  
Vol 1 (4) ◽  
pp. 34-50
Author(s):  
Roee Anuar ◽  
Yossi Bukchin ◽  
Oded Maimon ◽  
Lior Rokach
Keyword(s):  
Recommender Systems ◽  
Entropy Measure ◽  
Continuous Data ◽  
System Evaluation ◽  
Rating Data ◽  
New Approach ◽  
Selection Of ◽  
Classical Entropy ◽  
Better Than

The task of a recommender system evaluation has often been addressed in the literature, however there exists no consensus regarding the best metrics to assess its performance. This research deals with collaborative filtering recommendation systems, and proposes a new approach for evaluating the quality of neighbor selection. It theorizes that good recommendations emerge from good selection of neighbors. Hence, measuring the quality of the neighborhood may be used to predict the recommendation success. Since user neighborhoods in recommender systems are often sparse and differ in their rating range, this paper designs a novel measure to asses a neighborhood quality. First it builds the realization based entropy (RBE), which presents the classical entropy measure from a different angle. Next it modifies the RBE and propose the realization based distance entropy (RBDE), which considers also continuous data. Using the RBDE, it finally develops the consent entropy, which takes into account the absence of rating data. The paper compares the proposed approach with common approaches from the literature, using several recommendation evaluation metrics. It presents offline experiments using the Netflix database. The experimental results confirm that consent entropy performs better than commonly used metrics, particularly with high sparsity neighborhoods. This research is supported by The Israel Science Foundation, Grant #1362/10. This research is supported by NHECD EC, Grant #218639.

scholarly journals Fabrication of 3D Printing Scaffold with Porcine Skin Decellularized Bio-Ink for Soft Tissue Engineering

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3522
Author(s):  
Su Jeong Lee ◽  
Jun Hee Lee ◽  
Jisun Park ◽  
Wan Doo Kim ◽  
Su A Park
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
3D Printing ◽  
Three Dimensional ◽  
3D Bioprinting ◽  
Research Groups ◽  
Porcine Skin ◽  
Alginate Hydrogel ◽  
Chemical Treatments ◽  
Soft Tissue Engineering

Recently, many research groups have investigated three-dimensional (3D) bioprinting techniques for tissue engineering and regenerative medicine. The bio-ink used in 3D bioprinting is typically a combination of synthetic and natural materials. In this study, we prepared bio-ink containing porcine skin powder (PSP) to determine rheological properties, biocompatibility, and extracellular matrix (ECM) formation in cells in PSP-ink after 3D printing. PSP was extracted without cells by mechanical, enzymatic, and chemical treatments of porcine dermis tissue. Our developed PSP-containing bio-ink showed enhanced printability and biocompatibility. To identify whether the bio-ink was printable, the viscosity of bio-ink and alginate hydrogel was analyzed with different concentration of PSP. As the PSP concentration increased, viscosity also increased. To assess the biocompatibility of the PSP-containing bio-ink, cells mixed with bio-ink printed structures were measured using a live/dead assay and WST-1 assay. Nearly no dead cells were observed in the structure containing 10 mg/mL PSP-ink, indicating that the amounts of PSP-ink used were nontoxic. In conclusion, the proposed skin dermis decellularized bio-ink is a candidate for 3D bioprinting.

scholarly journals 3D Printing in Heterogeneous Catalysis—The State of the Art

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4534 ◽  
Author(s):  
Elżbieta Bogdan ◽  
Piotr Michorczyk
Keyword(s):  
Additive Manufacturing ◽  
Heterogeneous Catalysis ◽  
3D Printing ◽  
Chemical Synthesis ◽  
State Of The Art ◽  
Three Dimensional ◽  
Production Method ◽  
The State ◽  
Monolithic Catalysts ◽  
Selection Of

This paper describes the process of additive manufacturing and a selection of three-dimensional (3D) printing methods which have applications in chemical synthesis, specifically for the production of monolithic catalysts. A review was conducted on reference literature for 3D printing applications in the field of catalysis. It was proven that 3D printing is a promising production method for catalysts.

scholarly journals Experimental Investigation of Color Reproduction Quality of Color 3D Printing Based on Colored Layer Features

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2909 ◽  
Author(s):  
Jiangping Yuan ◽  
Jieni Tian ◽  
Chen Chen ◽  
Guangxue Chen
Keyword(s):  
3D Printing ◽  
Numerical Models ◽  
Three Dimensional ◽  
Chromatic Aberration ◽  
Structural Similarity ◽  
Color Reproduction ◽  
Color Test ◽  
Layer Sequence ◽  
Colored Layer

Color three-dimensional (3D) printing is an advanced 3D printing technique for reproducing colorful 3D objects, but it still has color accuracy issues. Plastic-based color 3D printing is a common color 3D printing process, and most factors affecting its color reproduction quality have been studied from printing materials to parameters in the fixed consecutive layers. In this work, and combined with variable stair thickness, the colored layer sequence in sliced layers of a specific 3D color test chart is deliberately changed to test the effects of colored layer features on its final color reproduction quality. Meanwhile, the colorimetric measurement and image acquisition of printed 3D color test charts are both achieved under standard conditions. Results clearly show that the chromatic aberration values and mean structural similarity (MSSIM) values of color samples have a significant correlation with the colored stair thickness, but both did not display a linear relationship. The correlation trends between colored layer sequence and the above two indexes are more localized to the colored stair thickness. Combined with color structural similarity (SSIM) maps analysis, a comprehensive discussion between colored layer features and color reproduction quality of color 3D printing is presented, providing key insights for developing further accurate numerical models.

scholarly journals Ultra-High Early Strength Cementitious Grout Suitable for Additive Manufacturing Applications Fabricated by Using Graphene Oxide and Viscosity Modifying Agents

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2900
Author(s):  
Alyaa Mohammed ◽  
Nihad Tareq Khshain Al-Saadi
Keyword(s):  
Graphene Oxide ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Design Method ◽  
Three Dimensional ◽  
Cementitious Materials ◽  
Fresh Properties ◽  
Manufacturing Applications ◽  
Mechanical Strengths ◽  
The Impact

One of the considerable challenges in the design of cementitious mixtures for additive manufacturing/three-dimensional (3D) printing applications is achieving both suitable fresh properties and significant mechanical strengths. This paper presents the use of graphene oxide (GO) as a promising nano reinforcement material with the potential to improve the printing feasibility and quality of a 3D printed cementitious matrix. Additionally, in this study, a viscosity modifying agent (VMA) was employed as a chemical additive to attain the required consistency and flow. The printed mixture was fabricated using various cementitious materials and waste materials. This study investigated the impact of GO and VMA on the enhancement of the 3D printing of cementitious composites through several tests. A flow test was conducted using the flow table test. The results showed a high fluidity and practical consistency, which are essential for nozzle pumping and accurateness in printed shapes. Furthermore, the bleeding test showed minimal bleeding up to hardening, and a considerable self-cleaning ability was noted during handling when conducting examinations of fresh properties. For hardened properties, the mechanical strengths were exceptionally high, especially at early ages, which is crucial for the stability of sequence layers of printed composites. The tensile strengths were 3.77, 10.5, 13.35, and 18.83 MPa at 1, 3, 7, and 28 days, respectively, and the compressive strengths were 25.1, 68.4, 85.6, and 125.4 MPa at 1, 3, 7, and 28 days, respectively. The test results showed the effectiveness of the fabricated cementitious mixture design method for meeting the requirements for 3D concrete printing applications.

Effects of Pig Skin and Coconut Powder Mixture on Gelling and Rheological Properties of Composite Gel Prepared with Squid Myofibrillar Protein and Lard

2018 ◽  
Vol 14 (1) ◽  
Author(s):  
Tiantian Zhou ◽  
Yana Zhao ◽  
Shengnan Fu ◽  
Wenhang Wang ◽  
Anjun Liu
Keyword(s):  
Rheological Properties ◽  
Three Dimensional ◽  
Myofibrillar Protein ◽  
Pig Skin ◽  
Composite Gels ◽  
Gelling Properties ◽  
Dimensional Network ◽  
Composite Gel ◽  
Sds Page

AbstractThe effects of the mixture of pig skin (PS) and coconut powder (CP) on the gelling and rheological properties of composite gel prepared with squid myofibrillar protein (MP) and lard were studied. The addition of PS and CP gel had significantly improved the water-holding capacity (WHC) and gelling properties of MP-Lard composite gel. Besides, composite gels with an adequate amount of PS and CP gel had a better texture and higher whiteness. The SDS-PAGE results showed that the presence of PS and CP gel did not affect the coagulated proteins in composite gels. The three-dimensional network structures of composite gels containing PS and CP gel were more compact and homogeneous. In general, the mixture of PS and CP could enhance the gel quality of MP-Lard composite gel and it could be used as a fat substitute in surimi products.

Restoration of Agricultural Machines Surfaces by White Cast Iron with the Formation of Technological Repair Units

2018 ◽  
Vol 927 ◽  
pp. 43-47
Author(s):  
V.K. Afanasyev ◽  
A.P. Chernysh ◽  
S.V. Dolgova
Keyword(s):  
Surface Layer ◽  
Cast Iron ◽  
White Cast Iron ◽  
Low Cost ◽  
Operating Conditions ◽  
Technological Environment ◽  
New Approach ◽  
Selection Of ◽  
Agricultural Machines

This article develops a fundamentally new approach in the selection of optimal methods for restoring of worn surfaces of agricultural machines’ tools with the formation and application of technological repair units. Based on the systematization and linkage of modular worn-out surfaces, their operating conditions, technological environment and the choice of their optimal combinations, it found a low-cost method of restoring details with white cast iron to gain a necessary quality of a new surface layer.

scholarly journals Three-dimensional Printing in Spine Surgery: Protocol of a Systematic Review and Meta-analysis

2020 ◽  
Author(s):  
Guanli Xie ◽  
Tao Wang ◽  
Bo Jiang ◽  
Chunyan Yang ◽  
Deguang Li ◽  
...  
Keyword(s):  
3D Printing ◽  
Spinal Surgery ◽  
Three Dimensional ◽  
Clinical Heterogeneity ◽  
Three Dimensional Printing ◽  
3D Printing Technology ◽  
Randomized Controlled ◽  
Randomized Controlled Studies ◽  
Dimensional Printing

Abstract BackgroundThe complexity and diversity of spine pathology lead to the complexity and diversity of spinal surgery. The emergence and application of three-dimensional printing (3DP) technology has brought good news to surgeons and patients. However, the use of 3DP in spinal surgery remains controversial. Therefore, this study was designed to investigate whether 3D printing technology is beneficial for spinal surgery.MethodsThree English online databases including EMBASE (via embase.com), Medline (via PubMed), and Cochrane Central Register of Controlled Trials (CENTRAL) will be searched from inception until August 31, 2020. Document records retrieved according to the pre-defined search strategy will be managed by EndNote X7. The MINORST (methodological index for non-randomized studies) item recommended for non-randomized controlled interventional studies in surgery will be used to assess the quality of non-randomized controlled studies. The “Risk of bias” (ROB) table will be used to assess the quality of randomized controlled studies. The data extraction will be completed by two authors independently, one of whom extracts and the other checks. If there is any missing data, original author will be contacted to obtain the data required. Any inconsistencies were agreed upon by discussion with a third investigator. If the collected data can be synthesized, Review Manager (RevMan5.3) will be used to estimate the overall effect of 3DP for Spinal surgery. Otherwise, only the qualitative analysis will be carried out. According to the results of clinical heterogeneity test, random effects model or fixed effects model will be used for data synthesis. The sources of clinical heterogeneity will be explored by meta-regression and subgroup analysis. If more than 10 studies are included, funnel plots will be used to assess the publication bias. This review will be carried out in strict accordance with Cochrane Handbook for Systematic Reviews of Interventions.ConclusionThis study will can provide surgeons and patients with evidence-based evidence for the use of 3D printing technology in spinal surgery.Systematic review registrationPROSPERO/ID = CRD42020204053.

scholarly journals Improvements on marker-free images alignment for electron tomography

2020 ◽  
Author(s):  
C.O.S. Sorzano ◽  
F. de Isidro-Gómez ◽  
E. Fernández-Giménez ◽  
D. Herreros ◽  
S. Marco ◽  
...  
Keyword(s):  
Structural Information ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Reconstruction Process ◽  
New Approach ◽  
Alignment Procedure ◽  
Transmission Electron ◽  
Marker Free ◽  
Stem Tomography

AbstractElectron tomography is a technique to obtain three-dimensional structural information of samples. However, the technique is limited by shifts occurring during acquisition that need to be corrected before the reconstruction process. In 2009, we proposed an approach for post-acquisition alignment of tilt series images. This approach was marker-free, based on patch tracking and integrated in free software. Here, we present improvements to the method to make it more reliable, stable and accurate. In addition, we modified the image formation model underlying the alignment procedure to include different deformations occurring during acquisition. We propose a new way to correct these computed deformations to obtain reconstructions with reduced artifacts. The new approach has demonstrated to improve the quality of the final 3D reconstruction, giving access to better defined structures for different transmission electron tomography methods: resin embedded STEM-tomography and cryo-TEM tomography. The method is freely available in TomoJ software.

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