Universiti Sains Malaysia
  • George Town, Pulau Pinang, Malaysia
Recent publications
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for the rapid quantification of multiple mycotoxins, specifically aflatoxins B1, B2, G1, and G2 (AFB1, AFB2, AFG1 and AFG2), ochratoxin A (OTA), deoxynivalenol (DON), and zearalenone (ZEN), in walnuts, pistachios, peanuts, coffee beans, rice, and chickpeas from various countries. Total counts of fungi, Aspergillus flavus, and Aspergillus parasiticus were also assessed, along with the effectiveness of a decontamination treatment with inorganic selenium to reduce mycotoxin levels. Of the 78 samples tested, 69% were contaminated with mycotoxins. ZEN, the predominant mycotoxin contaminant, was detected in all the contaminated samples in concentrations often exceeding the maximum level, followed by AFG1 (28% of the contaminated samples), DON (22%), AFG2 (11%), and AFB1 (5.5%). The occurrence of aflatoxins was associated with high proportions of A. flavus and A. parasiticus. Complete removal of AFB1 from walnuts and DON from roasted coffee beans was achieved by treatment with aqueous selenium, while the levels of ZEN and AFG1 were respectively lowered by 65% to 89% depending on the commodity and by about 56% in roasted coffee beans. While this novel treatment is a promising approach for mycotoxin decontamination, it is not intended to replace safe practices upstream.
Over recent years, carbon quantum dots (CQDs) have advanced significantly and gained substantial attention for their numerous benefits. These benefits include their simple preparation, cost-effectiveness, small size, biocompatibility, bright luminescence, and low cytotoxicity. As a result, they hold great potential for various fields, including bioimaging. A fascinating aspect of synthesizing CQDs is that it can be accomplished by using biomass waste as the precursor. Furthermore, the synthesis approach allows for control over the physicochemical characteristics. This paper unequivocally examines the production of CQDs from biomass waste and their indispensable application in bioimaging. The synthesis process involves a simple one-pot hydrothermal method that utilizes biomass waste as a carbon source, eliminating the need for expensive and toxic reagents. The resulting CQDs exhibit tunable fluorescence and excellent biocompatibility, making them suitable for bioimaging applications. The successful application of biomass-derived CQDs has been demonstrated through biological evaluation studies in various cell lines, including HeLa, Cardiomyocyte, and iPS, as well as in medaka fish eggs and larvae. Using biomass waste as a precursor for CQDs synthesis provides an environmentally friendly and sustainable alternative to traditional methods. The resulting CQDs have potential applications in various fields, including bioimaging.
Applying a multistep approach, novel indolin-2-ones (IND) that possess an arylidene motif have been synthesized. Eight compounds were chosen for different biological tests (antimicrobial and cytotoxicity). IND containing 2-thienyl (4h) fragment have been found to exhibit good antimicrobial activity against B. cereus. Molecules that have 3-aminophenyl (4d) or 2-pyridyl (4g) groups have shown the best antifungal activities against all tested fungi. These compounds have also been noticed as promising pharmaceuticals against MCF-7 cancer cell lines. Experimental outcomes from the investigation of the interaction of 4d with DNA implied its moderate binding to DNA (KSV = 1.35 × 10⁴ and 3.05 × 10⁴ M⁻¹ for EB and Hoechst binder, respectively). However, considerably stronger binding of 4d to BSA has been evidenced (Ka = 6.1 × 10⁶ M⁻¹). In summary, IND that contains m-aminobenzylidene fragment (4d) exhibits a good dual biological activity making it a promising candidate for further investigation in the drug discovery sector.
The mechanical, thermal, and biodegradability properties of paddy straw powder (PSP)-filled polyhydroxybutyrate-3-valerate (PHBV) biocomposites were investigated. The impacts of chemical alteration of PSP via acrylic acid treatment were examined as well. The outcomes of the study portrayed a decrease in the elongation at break and tensile strength when the filler loading increased; however, the modulus elasticity of composites could be seen to increase. Chemical alteration of PSP via acrylic acid enhanced modulus elasticity of the biocomposites and tensile strength; nevertheless, the elongation at break was decreased. Thermogravimetric analysis demonstrated the enhancement of thermal stability of the biocomposites via PSP compared to neat PHBV. The thermal stability of the biocomposites was positively affected by chemical alteration of PSP. Meanwhile, DSC analysis proved that the melting temperature (Tm) of the biocomposites was not altered when the filler was added. Treated biocomposites demonstrated higher crystallinity (30.18%) compared to the untreated composites (26.24%). Biodegradability test showed the strains from both Aspergillus species have the potential to degrade PHBV/PSP biocomposites. The weight loss of biocomposites after undergoing fermentation with Aspergillus fumigatus strain SGE57 and Aspergillus niveus isolate A17 was 2.42% and 3.65%, respectively.
This work aimed to develop compatible blend between natural rubber (NR) and ethylene propylene diene rubber waste (w-EPDM). This was done by introducing third rubber matrix and electron-beam (EB) irradiation. As for the first method, natural rubber latex (NRL) was added where it was mixed with w-EPDM prior to blend with NRL on a two-roll mill. However, the latter route was prepared differently, EB-exposed to the samples in the presence of trimethylolpropane triacrylate (TMPTA) as cross-linking promoter. By applying these two methods, the compatible blends of NR and w-EPDM were successfully prepared. The blends exhibited good cure properties, solvent resistance, tensile, and dynamic mechanical properties. NR and w-EPDM were more entangled after introducing these two methods.
This study focused on the blends of natural rubber (NR) containing virgin ethylene propylene diene rubber (EPDM) and recycled ethylene propylene diene rubber (R-EPDM). The blends’ properties ranged from 90/10, 80/20, 70/30, 60/40, and 50/50 (phr/phr) of NR/EPDM and NR/R-EPDM blends were observed. Results showed that both mixtures decreased tensile strength and elongation at break. In contrast, thermal stability showed an opposite trend as the weight ratio of EPDM or R-EPDM increased. The minimum torque (ML), maximum torque (MH), torque difference (MH–ML), scorch time (ts2), and cure time (tc90) of the blends exhibited increasing trend over the loadings of virgin EPDM or R-EPDM. This can be evidently seen from SEM micrographs showing a decrement in crack path especially when adding virgin EPDM or R-EPDM over 30 phr. This has led to less resistance to crack growth and thus lowering strength of the blends.
Due to the migration of sulfur from one rubber to another, a blend of natural rubber (NR) containing ground ethylene propylene diene rubber waste (w-EPDM) may cause cure incompatibility between these two rubbers. Therefore, accelerator optimization was formulated to see the curing incompatibility in NR/w-EPDM blends and increase curative dispersion. In this study, four types of rubber accelerators were chosen, these included N-tert-butyl-2-benzothiazole-sulfonamide (TBBS), N-cyclohexyl-benzothiazole-sulfenamide (CBS), tetramethyl thiuram disulfide (TMTD), and 2-mercapto benzothiazole (MBT). Using CBS has given the blend with the highest tensile strength. Furthermore, SEM images of CBS-vulcanized NR/w-EPDM blends showed more cracks and roughness, suggesting higher force needed toward the specimen. The results from damping characteristic and storage modulus verified TMTD-vulcanized blend provided a higher level of crosslinking followed by the CBS-, TBBS-, and MBT-accelerated blend, respectively.
Polyethylene terephthalate (PET) is one of the major polymers produced and has been widely used in downstream industries, such as the production of textile fibers, packaging bottles, and films. The increased use of PET is associated with its excellent properties, which include thermal resistance, lightweight, high transparency, good impact, and relatively low cost. This indirectly contributes to a large amount of PET solid waste, which is detrimental to human life and exacerbates environmental issues. As a result, conversion to new PET blends and composites is an efficient method to recycle PET and reduce waste. While research in this area is ongoing and improving with the development of new materials for various applications, its commercialization has yet to begin. This chapter focuses on the designation of recycled PET and its performance as new blends and composites. Among the other topics discussed are PET waste sources, recycling methods, and applications, as well as the challenges of recycling PET and converting this solid waste into value-added products.
Utilization of rubber waste and changing it into processable form are challenge for rubber material. An idea to blend rubber waste with virgin rubber is keen interest. This is to obtain compromising properties from both rubbers. In this chapter, natural rubber (NR) and chloroprene rubber waste (w-CR) were blended to synergistic properties of strength and solvent resistance provided by NR and w-CR. The focus was specifically on the action of metal oxide content on the overall properties of the blends. This was to enhance the final performance of the blends. The metal oxide used in the formulation was to be as curing activator, curing agent, and reinforcing filler. The results observed that introducing metal oxide has provided an excessive density of crosslinking and agglomeration which then reduced the overall performance of the blends. In summary, the content of metal oxide suggested for the NR/w-CR blend was 4 phr of MgO and 10 phr of ZnO.
An effective method to reduce rubber waste is to reuse it by blending with virgin rubber. There are many types of rubber that have been discarded, and chloroprene rubber is one of examples. Chloroprene rubber waste (w-CR) was used as blending component in this study where there are three types of virgin rubbers which were blended namely natural rubber (NR), epoxidized natural rubber with 50 mol% epoxidation level (ENR50), and styrene butadiene rubber (SBR). In this chapter, effects of blending ratio, i.e., 95/5, 85/15, 75/25, 65/35, and 50/50 (phr/phr) on properties, were studied. w-CR has lengthened the scorch and curing times of all blends due to their cure mismatch between two types of rubber. w-CR has also influenced the maximum torque (MH), minimum torque (ML), and torque difference (MH-ML) in all cases. This is simply because w-CR possesses the cross-linked precursor and its rigidity in nature. This further affected to increase in swelling resistance, overall cross-link density and thermal stability of the blends.
Thermoplastics being a modern material had provided significant contribution to human civilization. Polyethylene (PE) being the highest consumed thermoplastic is gaining more momentum in production for application in the field of automotive, electrical, and food packaging. Environmental issues with single-usage trend of PE products had catalyzed various initiative to recycle PE specially to produce recycle PE blends and composites. Even though various laboratory-based development been successfully carried out to produce recycled PE blends and composites but its commercialization is still at infancy. Thus, in this chapter the current PE recycling methods, products, and its applications are being discussed and the challenges faced by industry for full-scale adaption of findings in laboratories are highlighted. Critical analysis on the production and products of recycled PE blends and composites are reported to provide the reader with future trends for practical approach in PE recycling at industrial scale.
The widespread use of plastic has led to an environmental crisis, with an estimated 6300 Mt. of plastic waste generated in 2018, of which only 9% was recycled, 12% burned, and 79% dumped in the environment or landfills. The production and disposal of plastics have a significant impact on the environment, with landfills and natural environments predicted to accumulate 12 billion tons of plastic waste by 2050. The COVID-19 pandemic has further increased plastic waste due to the use of personal protective equipment, disposable dinnerware, and plastic-wrapped food. To address this issue, a concerted global effort is needed to minimize plastic waste throughout the plastic lifecycle, including reducing waste output, increasing waste collection and recycling, and removing plastic pollution from the environment. Recycling plastic waste is critical, as it not only reduces the cost of garbage disposal but also helps recover energy from plastics and reduces the need for virgin materials. Composite materials, such as polymer–matrix composites, metal–matrix composites, and ceramic–matrix composites, offer superior quality, durability, and reduced energy usage, making them a popular choice in many engineering applications, particularly in the transportation industry. Good waste management systems are necessary for the proper disposal and recycling of composite materials. This chapter focuses on the recycling of composite materials as a way to address the growing issue of plastic waste and its impact on the environment.
Since the advent of hybridoma technology in the year 1975, it took a decade to witness the first approved monoclonal antibody Orthoclone OKT39 (muromonab-CD3) in the year 1986. Since then, continuous strides have been made to engineer antibodies for specific desired effects. The engineering efforts were not confined to only the variable domains of the antibody but also included the fragment crystallizable (Fc) region that influences the immune response and serum half-life. Engineering of the Fc fragment would have a profound effect on the therapeutic dose, antibody-dependent cell-mediated cytotoxicity as well as antibody-dependent cellular phagocytosis. The integration of computational techniques into antibody engineering designs has allowed for the generation of testable hypotheses and guided the rational antibody design framework prior to further experimental evaluations. In this article, we discuss the recent works in the Fc-fused molecule design that involves computational techniques. We also summarize the usefulness of in silico techniques to aid Fc-fused molecule design and analysis for the therapeutics application.
Classroom discourse has undergone a huge paradigm shift since educators had to shift to the online teaching mode during the “COVID-19” pandemic. Given such a scenario, engaging and maintaining students’ attention has been a challenge and the central focus of English as a Second Language (ESL) instructors at the tertiary level. Considering this shift, the present study explored how ESL educators in a private institution in Malaysia utilised interactions, time and pace in online classes during the pandemic to enhance teaching and learning. A qualitative research design comprising interviews, lesson observation on Microsoft Teams and field notes was employed. Eight instructors teaching ESL at higher education institutions were recruited using a convenience sampling method and the data from interviews were analysed thematically. The results from the three data collection methods were triangulated and combined to draw conclusions about the challenges of online teaching which define the dynamics of the classroom interaction. It was concluded that effective and well-planned classroom interactions, time management strategies and pacing were important effective aspects of online teaching which could facilitate or impede the routines of online classroom teaching. Findings of the present study may have implications for improving the quality of interactions in online teaching. The authors suggest solutions for the various challenges that online teaching poses for educators.
Concepts and applications of conventional phytoremediation in comparison to other phytotechnologies, that is, phytoextraction and phytostabilization, will be discussed. The prospects of phytoremediation as an eco-friendly and sustainable approach in heavy metal removal are analyzed. Lessons learned and future directions of successes and limitation of phytotechnologies at field scale application will be deliberated. Heavy metal accumulation in various environmental conditions associated with phytoremediation factors is reviewed. The appropriate phytoremediation protocol in terrestrial and aquatic environments in regard to photostabilization of metals is a way forward for captivating the significance of phytoremediation. The current state, problems, and prospects of phytoremediation of heavy metal polluted soils are analyzed along with the efficacy of phytoremediation at different states of heavy metal speciation. Advantages and disadvantages of phytoremediation as compared to other methods of remediation of heavy metal contaminated soils (naturally and anthropogenic) are areas of concern and partly discussed in this chapter. The examples of successful phytoextraction and phytomining for cleaning up of contaminated soils globally are presented.
Heavy metals presence in wastewater are usually associated with the usage of metal-based chemical substances such as inorganic coagulant, metal salt, and metal-based processing. Heavy metal is defined as an essential element that can be found in Earth. Few amounts of heavy metals would be beneficial for human beings, but excessive amounts of heavy metals would become a catastrophic disaster for the environment. Therefore, it is crucial to verify the water quality, mostly when even just 1.0 mg/L of the concentration may contribute a higher impact on the environment. The existing or the remaining low concentration of heavy metals of post-chemical treatment of polluted water of wastewater remains troublesome due to incompliance effluent discharge. This chapter will highlight the removal of heavy metals through bioremediation and biotransformation. Concomitantly the mechanism and the roles of extracellular polymeric substances (EPS) will be discussed.
The sustainable approach in industrial wastewater treatments required ensuring the environment’s conservation for the well-being of people, other living organisms, and the ecosystem which will be a prime topic of discussion in this chapter. The wastewater released from the industry generates various kinds of pollutants that harm human and aquatic life if not treated appropriately. The excessive concentration of toxic constituents in industrial effluents will seep into the environmental compartments and thus disturbing the ecosystem. Furthermore, groundwater systems also can be pretentious by all the toxicants due to leaching through the soil. This kind of toxicity may cause mutagenic and carcinogenic impacts not even to the aquatic organism but can result to severe damage to humans. Hence, in treating industrial wastewater, the goal is not only to comply with the stipulated regulations, but the practice should be of adopting a more sustainable approach that protects the environment.
Background Chronic kidney disease (CKD) is seen as a diverse disease and a primary contributor to global mortality. Malnutrition arises within chronic illness, which involves protein energy depletion and inadequate levels of essential nutrients. These factors increase the likelihood of death and the overall impact of the disease on affected individuals. Consequently, this study aims to utilize bibliometric and visual analysis to assess the current state of research, the latest advances and emerging patterns in the fields of CKD and malnutrition. Methods Extensive research was conducted using the Scopus database, which is the most authoritative database of research publications and citations, to focus on CKD research between 2003 and 2022, as indicated by title and author keywords. Then, within this vast collection of academic publications, a notable subset of articles was exclusively dedicated to investigating the relationship between CKD and malnutrition. Finally, we performed bibliometric analysis and visualization using VOSviewer 1.6.19 and Microsoft Excel 2013. Results Large global research between 2003 and 2022 resulted in 50,588 documents focused on CKD, as indicated by title and author keywords. In this extensive collection of scientific publications, a staggering portion of 823 articles is devoted exclusively to investigating the link between CKD and malnutrition. Further analysis reveals that this body of work consists of 565 articles (68.65%), 221 reviews (26.85%), and 37 miscellaneous entries (4.50%), which encompass letters and editorials. The USA was found to be the most productive country (n = 173; 21.02%), followed by Italy (n = 83; 10.09%), Sweden (n = 56; 6.80%), Brazil (n = 54; 6.56%) and China (n = 51; 6.20%). The most common terms on the map include those related to the topic of (a) malnutrition in hemodialysis patients and predicting factors; terms associated with the (b) impact of malnutrition on cardiovascular risk and complications in CKD patients; and terms related to the (c) dietary protein intake and malnutrition in CKD. Conclusions This study is the first of its kind to analyze CKD and malnutrition research using data from Scopus for visualization and network mapping. Recent trends indicate an increasing focus on protein-energy wasting/malnutrition in hemodialysis patients and predicting factors, dietary protein intake, and malnutrition in CKD. These topics have gained significant attention and reflect the latest scientific advances. Intervention studies are crucial to examining diet therapy's impact on patients with stages 1 to 5 CKD. We hope this study will offer researchers, dietitians and nephrologists valuable information.
This study aimed to explore the reinforcement effect of halloysite nanotubes (HNTs) in self‐healing natural rubber based on metal thiolate ion networks. The amount of HNTs was varied at five levels (2, 4, 6, 8, and 10 phr) in order to assess the optimum amount of filler for self‐healing efficiency and mechanical recovery performance. Fourier‐transform infrared (FTIR) provides evidence for the reversible ionic bonding, facilitated by Zn ²⁺ and S ⁻ bonding from the metal thiolate vulcanization with rubber molecular chains. Scanning electron microscopy (SEM) revealed that the NR/HNTs composites with lower filler loading exhibited better recovery, as there were no observable gaps between the cut surfaces of the samples. The results also revealed that addition of HNTs resulted in a significant improvement in the mechanical performance, particularly the tensile strength, which increased by approximately 20%–75%. Furthermore, the extent of healing after the broken pieces were brought in contact with each other varied from 87% to 98%, depending on HNT concentration. Highlights Fabrication of self‐healing elastomers based on natural rubber. Self‐healing NR presented enhanced mechanical performance with addition of HNTs. HNTs lumen endows the composites with excellent self‐healing efficiency. Developed NR/HNTs composite exhibited room temperature self‐healing properties. Reversible ionic bonding expedited by Zn ²⁺ contributes in excellent self‐healing.
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26,644 members
Tiem Leong Yoon
  • School of Physics
Zhari Ismail
  • Discipline of Pharmaceutical Chemistry
Mohd Rizal Arshad
  • School of Electrical and Electronic Engineering
Hasni Arsad
  • Advanced Medical and Dental Institute (AMDI)
Arman Zaharil Mat Saad
  • Reconstructive Sciences Unit
Jalan Sungai Dua, 11800, George Town, Pulau Pinang, Malaysia
Head of institution
Professor Dr. Faisal Rafiq Mahamd Adikan