Science and Technology of Additive Manufacturing Progress: Processes, Materials, and Applications.

As a special review article, several significant and applied results in 3D printing and additive manufacturing (AM) science and technology are reviewed and studied. Which, the reviewed research works were published in 2020. Then, we would have another review article for 2021 and 2022. The main purpose is to collect new and applied research results as a useful package for researchers. Nowadays, AM is an extremely discussed topic and subject in scientific and industrial societies, as well as a new vision of the unknown modern world. Also, the future of AM materials is toward fundamental changes. Which, AM would be an ongoing new industrial revolution in the digital world. With parallel methods and similar technologies, considerable developments have been made in 4D in recent years. AM as a tool is related to the 4th industrial revolution. So, AM and 3D printing are moving towards the fifth industrial revolution. In addition, a study on AM is vital for generating the next developments, which are beneficial for human beings and life. Thus, this article presents the brief, updated, and applied methods and results published in 2020.

Using different unit-cell geometries to generate bone tissue scaffolds by additive manufacturing technology.

The design and manufacturing three-dimensional scaffolds are a significant concept in bone tissue engineering (BTE). Firstly, from the perspective of manufacturing, Additive manufacturing (AM) technology has achieved great attraction in the field of BTE during the past few years. In the field of BTE, the possibility of generating complex porous structures with high precision compared to typical manufacturing methods has made AM the leading option for scaffold production. Secondly, from the design perspective, design porous scaffold plays a decisive role in BTE since scaffold design with an appropriate architectures have to lead to proper strength and porosity. The purpose of this research is extraction of optimal architecture to achieve maximum mechanical strength of BTE scaffolds. Hence, the geometry structures of the unit-cell have been selected in Cube, Cylinder and Hexagonal prism. On the other hand, for considering the porosity effects, three different unit-cell size have been chosen, and a total of nine scaffolds have been designed. Designed scaffolds were fabricated using Fused Deposition Modeling (FDM) 3D Printer and dimensional features of scaffolds were evaluated by comparing the designed scaffolds with scanning electron microscope (SEM). The specimens were exposed to mechanical compression test and the results were validated with the finite element analysis (FEA). Verified experimental and FEM results offered an excellent possible unit-cell geometry to be applied in design and manufacturing of BTE scaffolds.

The effect of nanocrystalline cellulose on flow properties of fiber crop aqueous suspension.

Nanocrystalline cellulose (NCC) a nature-based material, has gained significant attentions for its unique properties. The present study aims to investigate the flow behavior of cellulosic suspension containing non-wood pulp fibers and NCC, by means of rheological and pressure drop measurements. The NCC sample was prepared by sulfuric acid hydrolysis from Acacia mangium fibers. The rheological properties of kenaf/NCC suspensions were studied using viscosity and yield stress measurements. The pressure drop properties of the suspension flow were studied with respect to variation in flow velocity (0.4 m/s-3.6 m/s) and the NCC concentration (70 mg/l and 150 mg/l). The pressure drop results showed that the pulp suspension containing 150 mg/l NCC had higher drag reduction than kenaf suspension alone. The present insights into the flow of pulp/NCC suspension provide a new data and promote the application of NCC in industries.

Characterization and Influence of Green Synthesis of Nano-Sized Zinc Complex with 5-Aminolevulinic Acid on Bioactive Compounds of Aniseed.

A new water soluble zinc-aminolevulinic acid nano complex (n[Zn(ALA)2 ]), which was characterized by TEM, IR, and EDX spectra, has been prepared via sonochemical method under green conditions in water. In the current study, the effectiveness of foliar Zn amendment using synthetic Zn-ALA nano complex, as a new introduced Zn-fertilizer here, was evaluated. As the model plant, Pimpinella anisum, the most valuable spice and medicinal plant grown in warm regions, was used. By using zinc nano complex, further twenty compounds were obtained in the essential oil of anise plants. Application of 0.2% (w/v) Zn-ALA nano complex increased the levels of (E)-anethole, ß-bisabolene, germacrene D, methyl chavicol, and α-zingiberene in the essential oil. Nano Zn complex at the rate of 0.2% induced considerable high phenolic compounds and zinc content of shoots and seeds. Chlorogenic acid had the highest level between four detected phenolic compounds. The maximum antioxidant activity was monitored through the application of Zn nano complex. According to the results, nanoscale nutrients can be provided with further decreased doses for medicinal plants. Using Zn-ALA nano complex is a new and efficient method to improve the pharmaceutical and food properties of anise plants.

Antioxidant activity, polyphenolic contents and essential oil composition of Pimpinella anisum L. as affected by zinc fertilizer.

BACKGROUND: The antioxidant activity and essential oil content of plants may vary considerably with respect to environmental conditions, especially nutrient availability. Among micronutrients, zinc (Zn) is needed by plants in only small amounts but is crucial to plant development. This study aimed to evaluate the effects of Zn fertilization on the antioxidant activity, polyphenolic contents and essential oil composition of Pimpinella anisum fruit. RESULTS: Foliar application of Zn fertilizer considerably increased the number of detected essential oil components from 27 to 45. Zinc application at a rate of 0.2% (w/v) significantly enhanced the levels of ß-bisabolene, germacrene D, n-decane and α-zingiberene, whereas the opposite trend was observed for (E)-anethole and geijerene. Application of 0.2% Zn considerably increased the levels of phenolic compounds, with chlorogenic acid showing the highest content among eight phenolic compounds detected in treated plants. The maximum antioxidant activity was achieved through application of 0.2% Zn fertilizer. CONCLUSION: These findings indicated that the quality and quantity of anise fruit essential oil components were significantly altered by application of low levels of Zn. After foliar application of Zn, polyphenolic contents as well as antioxidant activity of anise fruit increased. Using Zn fertilizer is an efficient method to improve the pharmaceutical and food properties of anise fruit. © 2017 Society of Chemical Industry.

Synthesis and characterization of novel polymer-drug conjugates based on the poly(styrene-alt-maleic anhydride) as a potential method for drug release.

Six well known drugs, captopril, metformin-HCl, metroniazole, nortriptyline-HCl, fluoxetine-HCl and betahistin-HCl, were grafted to poly(styrene-alt-maleic anhydride) (PSMA). Grafting was attained by combining of anhydride groups in the PSMA with therapeutic agents containing NH, OH or SH groups. The covalently grafted drugs were identified by infrared, (1)H NMR and UV-Vis spectroscopy. The drug release data at different times fits well to the Korsmeyer-Peppas equation. The analysis of the exponent n of this model revealed a dominant Fickian diffusion mechanism under the in vitro conditions. Furthermore, mean dissolution time values (45.9 to 86.7 h) indicate a high resistance against drugs transport, the highest being obtained for betahistin-HCL.