Critical review of biodegradable and bioactive polymer composites for bone tissue engineering and drug delivery applications

In the determination of the bioavailability of drugs administered orally, the drugs’ solubility and permeability play a crucial role. For absorption of drug molecules and production of a pharmacological response, solubility is an important parameter that defines the concentration of the drug in systemic circulation. It is a challenging task to improve the oral bioavailability of drugs that have poor water solubility. Most drug molecules are either poorly soluble or insoluble in aqueous environments. Polymer nanocomposites are combinations of two or more different materials that possess unique characteristics and are fused together with sufficient energy in such a manner that the resultant material will have the best properties of both materials. These polymeric materials (biodegradable and other naturally bioactive polymers) are comprised of nanosized particles in a composition of other materials. A systematic search was carried out on Web of Science and SCOPUS using different keywords, and 485 records were found. After the screening and eligibility process, 88 journal articles were found to be eligible, and hence selected to be reviewed and analyzed. Biocompatible and biodegradable materials have emerged in the manufacture of therapeutic and pharmacologic devices, such as impermanent implantation and 3D scaffolds for tissue regeneration and biomedical applications. Substantial effort has been made in the usage of bio-based polymers for potential pharmacologic and biomedical purposes, including targeted deliveries and drug carriers for regulated drug release. These implementations necessitate unique physicochemical and pharmacokinetic, microbiological, metabolic, and degradation characteristics of the materials in order to provide prolific therapeutic treatments. As a result, a broadly diverse spectrum of natural or artificially synthesized polymers capable of enzymatic hydrolysis, hydrolyzing, or enzyme decomposition are being explored for biomedical purposes. This summary examines the contemporary status of biodegradable naturally and synthetically derived polymers for biomedical fields, such as tissue engineering, regenerative medicine, bioengineering, targeted drug discovery and delivery, implantation, and wound repair and healing. This review presents an insight into a number of the commonly used tissue engineering applications, including drug delivery carrier systems, demonstrated in the recent findings. Due to the inherent remarkable properties of biodegradable and bioactive polymers, such as their antimicrobial, antitumor, anti-inflammatory, and anticancer activities, certain materials have gained significant interest in recent years. These systems are also actively being researched to improve therapeutic activity and mitigate adverse consequences. In this article, we also present the main drug delivery systems reported in the literature and the main methods available to impregnate the polymeric scaffolds with drugs, their properties, and their respective benefits for tissue engineering

A critical look at an Islamic Gold investment account

This article assesses an Islamic gold investment account offered by an Islamic bank in Malaysia and analyses its pros and cons. We look into the product’s relative advantages and disadvantages compare to some other Islamic deposit products and conventional gold accounts. In process of the assessment we also come across some Shari’ah compliance related issues and some practices which needs to be scrutinized from Shari’ah, economic and social perspectives. Overall, our findings suggest the account to be worthwhile investment instrument for long-term saving instrument and promising venture at times of boom in gold prices. However, the account is considered as a risky and unfavorable investment when gold price is on fall or if the customer intends to keep his deposits for a brief period. Finally, we pose some questions to the reader to ponder upon about some possible implication of the product for the Islamic bank, its customer or the society at large

Reflections on local community identity by evaluating heritage sustainability protection in Jugra, Selangor, Malaysia

The purpose of this study is to evaluate the value derived by the local community from cultural heritage and natural heritage in Jugra, Kuala Langat, as it has the potential to be a recognized heritage tourism site. The quantitative approach was used by conducting a survey study. A total of 392 respondents among the local community were selected through a purposive sampling technique. The collected data were processed with SPSS software and analyzed using cross tabulation analysis. Then, several hypotheses were tested using AMOS software. The result showed that Jugra’s unique heritage elements positively influenced the respondent’s willingness to accept and fund its tourism development. Socioeconomic factors also influenced the respondents’ disposition to preserve heritage. The findings revealed that there was priceless value when respondents agreed with the development, although they had never visited the heritage sites. Their physical, economic, and social valuation made them proud of the heritage, as it is a reflection of their identity. This study also aims to emphasize the role of local community as one of the stakeholders, as they should also be able to benefit from tourism development. All these would help boost the tourism industry, particularly through the archaeo-tourism and eco-tourism perspectives

Investigation on vehicle dynamic behaviour during emergency braking at different speed

Safety system of the vehicle can be divided into two main categories; passive and active safety system. The purpose of the passive safety system is to protect the occupant during an accident, while active safety system allows the vehicle to be manoeuvred to avoid any collision. Although active safety system can prevent the accident, in a critical situation such as emergency braking, the dynamic behaviour of the vehicle changes abruptly, and the vehicle becomes unstable. The objective of this study is to analyse the dynamic behaviour of the vehicle during emergency braking with and without anti-lock braking system (ABS). In this study, the dynamic behaviour of the vehicle is observed by the simulation model that has been developed in the MATLAB-Simulink. The analysis vehicle model is Universiti Malaysia Pahang (UMP) test car, model Proton Persona. During braking, when ABS control unit detect the wheel is to lock-up, the hydraulic control unit closed the hydraulic valve to release the brake pad on the wheel. This allows the wheel to spin intermittently during braking. From the simulation results, when ABS is not applied to the vehicle, the front tires were lock-up and the vehicle become skidding. However, when ABS is applied, the speed of all tires decreased gradually and the vehicle is not skidding. The simulation results also show that the stopping distance with ABS is improved 28% compared without ABS

Creep test rig for cantilever beam: Fundamentals, prospects and present views

Cross arms in transmission tower are made up of Chengal wood, which degrade and collapse after a long period of service. This is due to creep deformation, and the rate of degradation is expedited due to exposure to extreme tropical climate. Hence, it is crucial to comprehend the early creep stage, which leads to structural failure. Apart from that, there are several research and industrial application gaps of these cross arms. For instance, creep life analysis of actual cross arms is still unexplored. In this study, the state-of-the-art is related to creep experiments and creep test rig designs, espacially on the creep test of a cantilever beam setup. The experimental methodologies implemented two vital approaches, conventional and accelerated techniques. The specific creep experiments on cantilever beam structure are emphasized and suggested in the manuscript as the building blocks for future design of cantilever creep test rig. This helps to guide future development design of cantilever beam creep test rig by fulfilling the specific criteria related to creep fundamentals, numerical modelling analysis, test operation for data evaluation, and development process. At the end, the challenges and improvements on the criteria existing design of test rigs are elaborated

Larvicidal efficacy screening of Anacardaciae crude extracts on the dengue hemorrhagic vector, Aedes aegypti

Vector-borne diseases are still rife because of the re-emergence of diseases transmitted by mosquitoes. The objective of this paper is to evaluate the larvicidal efficacy of crude leaf extract of Mangifera indica, Gluta renghas, and Melanochyla fasciculiflora against vector of dengue hemorrhagic fever, Aedes aegypti. These plant species are endemic species and widely distributed in Malaysian forests. Leaves of Ma. indica, G. renghas and M. fascculiflora were collected from Teluk Bahang National Park, Penang Malaysia. Fractions of leaves were segregated, air-dried, powdered and extracted using Soxhlet with methanol. The solvent was removed by using rotary evaporator to obtain the crude extract. Using WHO standard larval bioassay test method, third instar larvae of Aedes aegypti were exposed to concentration ranging from 200- 4500 ppm of methanol extract for all plant species. Larval mortality was observed after 24 hours exposure. The highest susceptibility and toxicity was recorded by Mangifera indica with the lowest concentration at 800 ppm followed by M. fasciculiflora and G. renghas. This indicates that crude plant extract is very effective in killing Ae. aegypti mosquitoes. This finding may lead to new low cost alternative, environmentally friendly method for mosquito control programs. To our knowledge, this is the first report on larvicidal bioefficacy from endemic Malaysian plants

Effect of hydrolysis time on the morphological, physical, chemical, and thermal behavior of sugar palm nanocrystalline cellulose (Arenga pinnata (Wurmb.) Merr)

Sugar palm nanocrystalline celluloses (SPNCCs) were isolated from sugar palm fiber (SPF). In this study, acid hydrolysis (60 wt. %) at different reaction times (30, 45, and 60 min) was carried out to investigate the optimum yield of NCC. The physical properties, degree of polymerization, chemical composition, structural analysis, crystallinity, surface area and charge, zeta potential, thermal analysis, and morphological characterization were also conducted to determine the outcome (efficiency) of the process. The results showed that a needle-like shape was observed under transmission electron microscopy (TEM) studies. TEM analysis showed optimum aspect ratios of 13.46, 14.44, and 13.13 for isolated SPNCC-I, SPNCC-II, and SPNCC-III, respectively. From thermogravimetric analysis (TGA), the degradation temperature of NCC decreased slightly from 335.15? to 278.50? as the reaction time increased. A shorter hydrolysis time tended to produce SPNCC with higher thermal stability, as proven in thermal analysis by TGA. The optimal isolation time was found to be around 45 min at 1200 rpm during hydrolysis at 45? with 60% sulfuric acid. Therefore, the extracted SPNCC from SPF has huge potential to be utilized in the bionanocomposite field for the production of biopackaging, biomedical products, etc

Micro-and nanocellulose in polymer composite materials: A review

The high demand for plastic and polymeric materials which keeps rising every year makes them important industries, for which sustainability is a crucial aspect to be taken into account. Therefore, it becomes a requirement to makes it a clean and eco-friendly industry. Cellulose creates an excellent opportunity to minimize the effect of non-degradable materials by using it as a filler for either a synthesis matrix or a natural starch matrix. It is the primary substance in the walls of plant cells, helping plants to remain stiff and upright, and can be found in plant sources, agriculture waste, animals, and bacterial pellicle. In this review, we discussed the recent research development and studies in the field of biocomposites that focused on the techniques of extracting micro-and nanocellulose, treatment and modification of cellulose, classification, and applications of cellulose. In addition, this review paper looked inward on how the reinforcement of micro-and nanocellulose can yield a material with improved performance. This article featured the performances, limitations, and possible areas of improvement to fit into the broader range of engineering applications

Thermogravimetric analysis properties of cellulosic natural fiber polymer composites: a review on influence of chemical treatmentst

Natural fiber such as bamboo fiber, oil palm empty fruit bunch (OPEFB) fiber, kenaf fiber, and sugar palm fiber-reinforced polymer composites are being increasingly developed for lightweight structures with high specific strength in the automotive, marine, aerospace, and construction indus-tries with significant economic benefits, sustainability, and environmental benefits. The plant-based natural fibers are hydrophilic, which is incompatible with hydrophobic polymer matrices. This leads to a reduction of their interfacial bonding and to the poor thermal stability performance of the resulting fiber-reinforced polymer composite. Based on the literature, the effect of chemical treatment of natural fiber-reinforced polymer composites had significantly influenced the thermogravimetric analysis (TGA) together with the thermal stability performance of the composite structure. In this review, the effect of chemical treatments used on cellulose natural fiber-reinforced thermoplastic and thermosetting polymer composites has been reviewed. From the present review, the TGA data are useful as guidance in determining the purity and composition of the composites’ structures, drying, and the ignition temperatures of materials. Knowing the stability temperatures of compounds based on their weight, changes in the temperature dependence is another factor to consider regarding the effectiveness of chemical treatments for the purpose of synergizing the chemical bonding between the natural fiber with polymer matrix or with the synthetic fibers

A review on natural fiber reinforced polymer composite for bullet proof and ballistic applications

Even though natural fiber reinforced polymer composites (NFRPCs) have been widely used in automotive and building industries, there is still a room to promote them to high-level structural applications such as primary structural component specifically for bullet proof and ballistic applications. The promising performance of Kevlar fabrics and aramid had widely implemented in numerous ballistic and bullet proof applications including for bullet proof helmets, vest, and other armor parts provides an acceptable range of protection to soldiers. However, disposal of used Kevlar products would affect the disruption of the ecosystem and pollutes the environment. Replacing the current Kevlar fabric and aramid in the protective equipment with natural fibers with enhanced kinetic energy absorption and dissipation has been significant effort to upgrade the ballistic performance of the composite structure with green and renewable resources. The vast availability, low cost and ease of manufacturing of natural fibers have grasped the attention of researchers around the globe in order to study them in heavy armory equipment and high durable products. The possibility in enhancement of natural fiber’s mechanical properties has led the extension of research studies toward the application of NFRPCs for structural and ballistic applications. Hence, this article established a state-of-the-art review on the influence of utilizing various natural fibers as an alternative material to Kevlar fabric for armor structure system. The article also focuses on the effect of layering and sequencing of natural fiber fabric in the composites to advance the current armor structure system