Studies On Mold Extracts As Potential Therapeutic Agents For Hepatitis C And Dengue Diseases

Dengue (DENV) and hepatitis C viruses (HCV) are from the Flaviviridae family. DENV causes 50 -100 million dengue hemorrhagic fever or dengue shock syndrome with more than 20, 000 deaths globally. While HCV causes chronic liver diseases to 150 million people globally. Up to date there is no antiviral drug for DENV while HCV antivirals are performing below par. In the search for an antiviral drug for HCV and DENV, extracts from Malaysian fungal isolates were tested. Fifty five fungal isolates were fermented separately on three different media namely, potato dextrose broth (PDB), complex media without phenylacetic acid (CM) and complex media with phenylacetic acid (CM+PA) at 30°C for 5 days. Mycelia-free supernatants were extracted (1:1) using methanol and ethyl acetate which produced 165 methanolic and 165 ethyl acetate crude extracts. Crude extracts (73 ethyl acetate and 61 methanolic) were subjected to HCV NS3/NS4A protease assay and extract with more than 95% inhibition activity were further fractionated using column chromatography. Determination of inhibition concentration at 50% (IC50), cytotoxicity and Gas Chromatography Mass Spectrometry (GCMS) analysis were performed on best active subfraction. Fungal isolate were identified using 18S rDNA sequencing. Crude extracts (45 ethyl acetate and 37 methanolic) that gave more than 80% HCV protease inhibition coherently were tested for DENV NS2B/NS3 protease inhibition activity. Most active crude extract was further fractionated and subfractions were tested using DENV NS2B/NS3 protease inhibition activity

Investigation of mechanical properties of 3d-printed polylactic acid (PLA)

In recent years, 3D printing has contributed to developing new materials and applications, owing to its technological flexibility and distinct characteristics. Polylactic Acid (PLA) polymer samples have been produced using one of the additive manufacturing (AM) processes called fused deposition modelling (FDM). However, poor mechanical characteristics are the most prevalent problem due to the processing parameter when parts are fabricated with FDM. The research aims to study the tensile properties of PLA by varying the processing parameter. In this study, PLA material was used due to its biocompatibility properties. This research is to analyze and compare the tensile properties of 3D printed samples by varying the infill density and raster angle. The change in the circumstances has a discernible impact on the tensile strength based on varied infill densities and raster angles. The results show that infill density of 100% and 45° raster angle performs better tensile strength than 50% and 75% infill density. Hence, it can be concluded that the tensile strength of the printed samples has a noticeable effect when the processing parameters vary

A review of FDM and graphene-based polymer composite

Graphene is a carbon that has a unique structure that is excellent in enhancing mechanical, electrical and thermal properties. The fused deposition modelling (FDM) process is a widely used 3D printing method for its low investment and operating cost. Although the FDM process is cheaper and affordable, yet the printed parts are more fragile compare to other 3D printing methods. This paper covers about FDM process and the type of base materials and filler materials. However, the focus is mainly on ABS and graphene. The mechanical properties of ABS/Graphene polymer composite and application of ABS and graphene in the industry were also discussed. Hence, it proved that graphene enhances the properties of ABS. This study is done to improve polymer-based filaments for future references

Preliminary investigation on the tensile properties of FDM printed PLA/copper composite

Recently, the rapid manufacturing of custom polymer-based composite components has been revolutionized by the Fused deposition modeling (FDM) process. Understanding the fundamental mechanical behaviours of these FDM-printed components is essential for engineering applications. FDM has been highly used inadditive manufacturing (AM) due to its ability to process complex parts with the lowest cost and accurate dimensions. The materials used are thermoplastic polymers, which are in the form of a filament. The aim of this study is to create testing specimens with varying infill percentages (25%, 50%, and 75%) and infill patterns (rectilinear, honeycomb, grid, concentric, and triangle) using the FDM technique on Polylactic acid (PLA) and PLA/Copper. The specimen is printed in accordance with the ASTM standard for tensile testing, which is ASTM D638. Following that, the mechanical properties of copper are assessed using tensile testing. The results demonstrate that the infill pattern for a triangle PLA/Copper specimen and concentric PLA specimen for 75% infill percentage produced the best performance in tensile strength; meanwhile, the grid copper pattern has the weakest properties among all the patterns. This research will be helpful to enhance the mechanical properties of the products in the electronics applications

A review on 3D printing bio-based polymer composite

Polymers play a vital role in our daily lives. In various fields such as medical, food industry and automotive applications, the use of biopolymers is commonly used. The most widely used polymers and fillers among biopolymers are polylactic acid (PLA) and cellulose, which are biocompatible and biodegradable due to their eco-friendly properties. Extensive usage of cellulose in various forms has been applied in combination to PLA but there is only a few research that has been done by using the 3D printing method. This paper covers the types of biodegradable biopolymer materials, types of coupling agents and plasticizers, mechanical properties and applications. This paper discusses the types of cellulose ranging from micro to nano, including other types and sources of cellulose that have been researched and are compatible with PLA. In order to generate biocompatible polymers with stronger and better mechanical properties, the findings of these experiments are all tied together. These biopolymers are commonly used in the biomedical industry and are expected to improve their benefits in this field

Thermo-mechanical properties of ABS/stainless steel composite using FDM

Fused deposition modelling (FDM) process is the most common and traditional additive manufacturing methods for producing complicated three-dimensional (3D) samples from computer-aided design data at a cheaper cost than alternative methods. However, when compared to other common plastic production processes, such as injection moulding, FDM produced parts results in low mechanical properties. Hence, the objective of this study is to produce composite filament using stainless steel (SS) as filler material to enhance the mechanical properties of ABS. ABS is a petroleum based thermoplastic that commonly used in FDM. The production of metal/polymer composites utilising ABS as the matrix and varied SS powder compositions was studied in this work. ABS/SS composite filaments containing 5, 10 wt% SS powder were developed in this experiment to compare with pure ABS for the FDM process. The result shows that the higher the composition of SS powder the lower the ultimate tensile strength and yield strength where 10 wt% SS shows 38.42 MPa in ultimate tensile strength while for yield strength it shows 24.32 MPa. Meanwhile, 10 wt% SS filament has better elongation which is 18.28 % compare to pure ABS that is 9.89 % and 13.3 % for 5 wt% SS. Thus, the percentage of filler plays an important role in determining the properties of ABS

Effect of process parameter on tensile properties of FDM printed PLA

In recent years, 3D printing has contributed to developing new materials and applications, owing to its technological flexibility and distinct characteristics. Polylactic Acid (PLA) polymer samples have been produced using one of the additive manufacturing (AM) processes called fused deposition modelling (FDM). However, poor mechanical characteristics are the most prevalent problem due to the processing parameter when parts are fabricated with FDM. The research aims to study the tensile properties of PLA by varying the processing parameter. In this study, PLA material was used due to its biocompatibility properties. This research is to analyze and compare the tensile properties of 3D printed samples by varying the infill density and raster angle. The change in the circumstances has a discernible impact on the tensile strength based on varied infill densities and raster angles. The results show that infill density of 100% and 45° raster angle performs better tensile strength than 50% and 75% infill density. Hence, it can be concluded that the tensile strength of the printed samples has a noticeable effect when the processing parameters vary

A comprehensive review on fused deposition modelling of polylactic acid

Fused Deposition Modelling (FDM) is one of the additive manufacturing (AM) techniques that have emerged as the most feasible and prevalent approach for generating functional parts due to its ability to produce neat and intricate parts. FDM mainly utilises one of the widely used polymers, polylactic acid, also known as polylactide (PLA). It is an aliphatic polyester material and biocompatible thermoplastic, with the best design prospects due to its eco-friendly properties; when PLA degrades, it breaks down into water and carbon dioxide, neither of which are hazardous to the environment. However, PLA has its limitations of poor mechanical properties. Therefore, a filler reinforcement may enhance the characteristics of PLA and produce higher-quality FDM-printed parts. The processing parameters also play a significant role in the final result of the printed parts. This review aims to study and discover the properties of PLA and the optimum processing parameters. This review covers PLA in FDM, encompassing its mechanical properties, processing parameters, characterisation, and applications. A comprehensive description of FDM processing parameters is outlined as it plays a vital role in determining the quality of a printed product. In addition, PLA polymer is highly desirable for various field industrial applications such as in a medical, automobile, and electronic, given its excellent thermoplastic and biodegradability properties