Science Letters

Electrical and Mechanical Properties of Silicone Electrically Conductive Adhesive (ECAs) Filled Graphene-Carbon Black (GR-CB)

Thu, 30 Jan 2025 00:00:00 +0100

ECAs were successfully introduced to replace hazardous lead-based solder, but their electrical conductivity and mechanical properties are limited. Hence, the incorporation of carbon black (CB) and Graphene (GR) filled silicone based ECAs with various ratios of GR and CB (0:0, 1:0, 0:1, 10:5, 5:10, 5:5, and 3:5) via solvent casting technique was investigated. The characterization of the conductive adhesive film using Fourier Transform Infrared Spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS) was investigated using the Nyquist plot and conductivity of silicone film. Meanwhile, the mechanical properties were measured using tensile and hardness tests. The appearance of a sharp peak in the FTIR spectrum confirmed that the interaction between the silicone matrix and GR-CB occurred (Si-CH3). The optimum ratio with the highest conductivity value, 7.98 10-8 Ω cm-1, was obtained by the synergistic effect of conductive fillers, which is GR with CB at 10:5 GR-CB ratio, which might be attributed to the synergistic effect from the filler. At the same time, tensile and hardness tests on silicone ECA samples exhibited that the optimum ratio of synergistic GR-CB was at 5:10 with the highest tensile strength, young modulus, elongation at break, and hardness with values of 1.16 MPa, 2.02 MPa, 25.64 mm, and 47.56, respectively due to the inherent stiffness of CB and GR. Finally, the electrical and mechanical properties revealed that adding GR and CB improved the conductivity, strength, and toughness of silicone ECAs composites, making way for electronic applications.

Transformative Approaches to Produce PHAs from Waste Streams: A Brief Review

Norazlina Hashim — Thu, 30 Jan 2025 00:00:00 +0100

Throughout their existence, plastics made from petroleum have been associated with increasing environmental problems, such as pollution, accumulation in terrestrial and marine environments, and the release of greenhouse gases. To address the present ecological concerns, creating and producing eco-friendly polymers has received much attention in the industrial and research communities over the past ten years. The current review focuses on one of the beneficial products obtained after the waste treatment. The biodegradable polymer, Polyhydroxyalkanoates (PHAs), is synthesised from the variable organic materials collected during the waste aerobic and anaerobic treatment. PHAs with short-chain-length (scl-PHA) and medium-chain-
length (mcl-PHA) are commonly synthesized with different bacterial strains as a factor to determine the chain length. Researchers studied various methods to find the optimum parameters and yield of PHAs while considering the cost. It can be concluded that pH 7 and 60 oC are the optimum conditions for bacteria pretreatment to obtain a high conversion of PHAs. Furthermore, one of the potential wastes, Palm Oil Mill Effluent (POME) obtained from palm oil production, was highlighted since Malaysia is the world's second-largest palm oil industrial player. The abundance of POME becomes highly toxic effluent and causes water pollution. Hence, POME can be manipulated to play an important role as one of the feedstocks for PHAs. This renewable PHAs biopolymer can solve the plastic degradation and the pollution caused by conventional polymers. The continuing improvement of PHAs was extensively examined to fulfil the world PHAs market demand.

Synthesis and Characterization of Superhydrophobic Alumina-Silane Sol-gel Coating

Ahmad Lutfi Anis, Gumel S. M., Bashir U.G., Umar A., Bawa A. A., Jibril L. A. — Thu, 30 Jan 2025 00:00:00 +0100

Superhydrophobic surfaces have attracted significant research interest because of their use for the design of water-repellent and self-cleaning coatings. A superhydrophobic surface can be created by modifying a rough surface with a low surface energy material through a sol-gel coating technique. Adjusting the amount of precursor and the low surface energy material can optimise the hydrophobicity of the coating. In this work, different ratios (4:1, 3:2, 1:1 and 2:3) of silane: alumina coatings were synthesised and applied on glass substrates through the sol-gel method. Characterisation of the coated samples showed that volume ratios of silane sol and alumina sol in sol-gel coating affected the superhydrophobicity of the coated glass substrate. The solution of alumina sol and silane sol with a ratio of 4:1 produced superhydrophobic films with a contact angle for water larger than 150 , and FESEM images showed very intense roughness compared to the other ratios.

Synthesis and Analytical Characterization of Monoazo Bifunctional Reactive Dyes on Cotton

Bashir U.G., Sani M. G., Aliyu B.A., Umar A., Zainab H. — Thu, 30 Jan 2025 00:00:00 +0100

In this study, two monodichlorotriazinyl reactive dyes were synthesised. The synthesis involved diazotisation, coupling with 1- naphthol-8-amino3-6-disulphomic acid (H-acid), and condensation with cyanuric chloride. The reactive dyes were applied on grey cotton fabric to assess dyeing performance. Spectrophotometric studies were carried out to investigate the wavelength of maximum absorption (λmax)—the percentage dye exhaustion, effects of temp. pH and duration of dyeing of the dyed samples were evaluated. The resultant dyes were characterized using standard spectroscopic methods. The results of the spectrophotometric analysis revealed that the λmax of the two dyes were 590mm and 600nm for dye (a) and (b), respectively. The maximum absorption wavelength of the dyes in ethanol, water, and acetone was 600nm and 590nm for dye (a) and 600, 570, and 480nm for (b). The %dye exhaustion was 70 – 80%, and the fastness rating was perfect and excellent.

Morphometric and Molecular Techniques for Sex Identification in Greater Coucal (Centropus sinensis intermedius)

Jessey Angat, Farida Zuraina Mohd Yusof — Thu, 30 Jan 2025 00:00:00 +0100

Accurate gender recognition in birds is crucial for research and conservation. Nevertheless, distinguishing sexes in weakly dimorphic birds poses challenges for conservationists, hindering efforts to boost endangered populations. Greater coucal exhibits weak Sexual Size Dimorphism (SSD) and lacks established criteria or methodology for morphometric sexing. Therefore, this study aimed to determine the sex of a weakly dimorphic bird by amplifying the CHDZ and CHDW genes, examining seven (7) morphological characters for standardisation of morphometric analysis using discriminant function analysis (DFA). Freshly plucked feathers from 66 Greater Coucals were used in Touchdown Polymerase Chain Reaction (tPCR), amplified a single Z band in males and both Z and W bands in females. Amplification of the
300-400 bp segment of the CHD1-Z gene and a 200-300 bp segment of CHD1-W using the 2550F/2718R primer set gene can be used to distinguish the sex of adult Greater coucal (males 30: females 36). The established function is (D = (-61.74) + (0.29) bill culmen length + (0.50) total head length + (0.60) bill depth) allowed for 100% correct
classification where female if D > 0 and male if D < 0. Thus, the formulated function equation, intended for practical application in the field, emphasises the potential for gaining valuable insights into diverse facets of the biology, behaviour, and ecology of monogamous bird species by exploring size differences. This first field-based, cost-effective study of sexual dimorphism in birds provides valuable resources for future
coucal management while offering important genetic and morphological data in Malaysia. It also provides the groundwork for more effective conservation and breeding programs, where accurate sex identification is crucial in decision-making.

Microalgae as Antimicrobial and Antibiofilm Agents: A Review

Syaza Syasya Lakman, Nurul Aili Zakaria, Mohd Taufiq Mat Jalil — Thu, 30 Jan 2025 00:00:00 +0100

Bacterial biofilms produce the majority of medical infections, and biofilm formation is also associated with 60–70% of nosocomial infections. It has become a huge public health concern as antibiotics' effectiveness is dwindling at an alarming rate due to the emergence of antibiotic-resistant microbes. Microalgae, both eukaryotic and prokaryotic, have been found to produce intracellular and extracellular metabolites with a variety of biological activities, such as antibacterial, antifungal, antiviral, and antibiofilm activity by microalgae and cyanobacteria species. Several compounds have been reported to possess antimicrobial and antibiofilm activity, including phenol, hexadecanoic acid, phycocyanin, phycobiliproteins, hassallidin, parsinguine, gambierdic acids, tannins, terpenoids, and flavonoids. This review outlines the uses of microalgae as a renewable and underexploited resource for antimicrobial and antibiofilm agents and their prospects.

The Relationship between Reproductive Hormones with General Behaviour of Captive Female Bornean Orangutans at Bukit Merah Orang Utan Island, Perak

Thu, 30 Jan 2025 00:00:00 +0100

Managing critically endangered species in captivity, like the orangutans (Pongo pygmies), requires deep knowledge of their physiology and behaviour to provide the best husbandry under human care. Progesterone and estrogen, the main hormones in the reproductive cycle, play an essential role in controlling behaviour in female mammals. However, the influence of hormones on behaviour in non-human primates, such as orangutans, is still very limited. This study investigates the impact of progesterone and estrogen in captive female orangutans at Bukit Merah Orang Utan Island, a conservation centre in Perak, Malaysia. The research explores the relationship between progesterone and estradiol levels with aggressive behaviour and daily activities. Faecal sampling and behavioural observation were conducted over 93 days from March 2021 until June 2021. A total of 101 faecal samples were collected from four female orangutans named Baboon (age 33), Careena (age 15), April (age 13), and Kate (age 9) for enzyme-linked immunosorbent assay (EIA) via commercial kits. Behavioural observation was conducted for 337 hours via focal and scan sampling. Aggression and four daily activities were observed, which included playing, moving, resting, and feeding. Overall, the results indicate that progesterone significantly correlates with resting, playing, and aggression behaviours, while estradiol shows no significant relationship with any behaviours. A Spearman’s correlation coefficient showed a significant but moderate positive relationship between progesterone concentration and resting behaviour, r[101]=0.462, p=0.006, and with playing behaviour, with a moderate negative relationship, r[101]=-0.439, p=0.015. A Spearman's correlation coefficient revealed a significant moderate negative relationship between aggression and the level of progesterone, r[101]=- 0.440, p=0.009. There was no correlation between estradiol and any behaviours with p>0.05. The findings of this study will enhance the knowledge of orangutan physiology and support conservation efforts by providing data that can be used to optimise the reproductive health and well-being of captive orangutans. This research is a step towards ensuring the survival of this critically endangered species by improving the conditions under which they are kept and managed in captivity.

A Mini Review on Biofilm-Mediated Water Pollution: Mechanistic Interactions, Preventive Approaches, and Removal Strategies

Thu, 30 Jan 2025 00:00:00 +0100

Biofilm formation significantly contributes to water pollution and infrastructure degradation in various industrial, urban, and marine environments. Biofilms can colonise various surfaces, including sediments, plants, and man-made structures. This colonisation negatively impacts water quality and the integrity of water distribution systems. Biofilms can also harbour pathogenic microorganisms, posing health risks in drinking water systems. This mini-review discussed how biofilm-related processes, such as clogged pipes, bio corrosion, and marine biofouling, can lead to water pollution and their broader environmental and economic implications. Biofilm buildup can trap contaminants, weaken pipe structures, cause localised corrosion, increase the surface roughness of ship hulls, and contribute to higher
operational costs and harmful emissions. Surface modification and managing hydrodynamic conditions effectively mitigate water pollution in various aquatic environments. Effective biofilm removal strategies include high-pressure water jets, ultrasonic treatment, enzyme-based cleaning, and oxidising agents. In conclusion, biofilms are a major contributor to water pollution and infrastructure damage across various environments, highlighting the urgent need for innovative and effective biofilm management strategies. Combined with regulatory frameworks and public awareness, these measures can significantly reduce biofilm-mediated water pollution's environmental and economic impacts

In Silico Identification of Essential Transmembrane Proteins in Salmonella typhimurium as Potential Drug and Vaccine Targets

Sat, 10 May 2025 00:00:00 +0200

Salmonella sp. is a globally prevalent organism responsible for causing salmonellosis, a foodborne illness. Salmonella typhimurium is a strain of Salmonella sp. that is not associated with typhoid fever but can cause gastrointestinal inflammation and severe infection. Despite advancements in genomic and proteomic technologies, several proteins identified in S. typhimurium remain uncharacterized. Thus, the objective of the present study was to characterise the transmembrane proteins of S. typhimurium that could serve as potential drug and vaccine targets. In this study, 150 uncharacterized proteins from S. typhimurium were randomly selected from UniProtKB and analysed using PSORTb V3.0.3 and TMHMM. Identified
transmembrane proteins were further analyzed using DEG, BLASTp, ProtParam, ScanProsite, STRING 12.0, and VaxiJen 2.0. The results indicated that 32 uncharacterized proteins (21%) were predicted to be transmembrane proteins involved in various biological pathways. Among these transmembrane proteins, protein A0A2J0RKS1 was predicted to be essential, antigenic, and non-host homologous, suggesting its potential as a drug and vaccine target for combating salmonellosis. This study underscores the potential of computational biology in drug target discovery, particularly against pathogens like S. typhimurium.

Abnormal Behaviors in Captive Wildlife: To Keep or Not to Keep?

Thu, 30 Jan 2025 00:00:00 +0100

Wildlife in captivity serves several purposes, including research, conservation, agriculture, and tourism. Many zoos and wildlife parks are driven towards conservation roles as they help prevent endangered wildlife from becoming extinct. However, a captive environment is often not the best manifestation of the animal's
natural habitat, thus hindering them from performing natural behaviour as they would in the wild. This imposes stress on the captive animals, leading to the display of abnormal behaviours, such as stereotypic behaviours, which are repetitive, invariant, and functionless behaviours. Stereotypic behaviours have been observed in many captive animals, such as pacing in tigers and bears, swaying and bobbing in elephants, over-grooming, self-mutilating, coprophilia, and coprophagia among captive primates, as well as fur and/or feather plucking in primates and birds. This article explores the abnormal behaviours of captive animals in response to their environment and highlights the critical importance of enrichment and naturalistic habitat design. Creating environments encouraging species-specific behaviours can significantly improve animal welfare, enhance conservation outcomes, and educate the public about wildlife conservation. Improved welfare practices not only support animal well-being but also strengthen public engagement and advocacy for conservation initiatives, ultimately aiding in protecting endangered species.

Anticancer and Anti-Angiogenic Potentials of Probiotics and Their Bioactive Metabolites Against Colorectal Cancer and its Tumour Microenvironment: A Narrative Review

Umi Khalsom Mohd Bajuri, Kalavathy Ramasamy, Siong Meng Lim — Thu, 30 Jan 2025 00:00:00 +0100

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths globally. Unfortunately, current cytotoxic chemotherapy and targeted therapy against CRC are compromised by side effects and cancer resistance. This calls for alternative prevention strategies. Given the majority of CRC are sporadic and associated with diet, probiotics(living microorganisms that, when consumed in an inadequate amount, confer health benefits on host) and their bioactive metabolites (postbiotics/functional compounds generated during fermentation) are deemed as viable options for chemoprevention against CRC. This narrative review highlights recent scientific evidence of the strain-dependent (single-/multi-strains) anticancer effects (action on CRC) as well as modulation of gut microbiota and angiogenesis (actions on tumour microenvironment) of probiotics and their bioactive metabolites. This review features the major mechanisms underlying the dual actions of probiotics and their bioactive metabolites against CRC. The anticancer effects of probiotics are related to reduced inflammation, cell apoptosis, suppressed tumour growth and viability, increased anti-oxidant activity and altered gut microbiota. The anti-angiogenic effects of probiotics are manifested through downregulation of pro-angiogenic VEGF and MMP2, MMP9, METTL3-related pathways, increased anti-angiogenic marker, decreased tumour microvascular density, tumour volume and tube formation as well as downregulation of angiogenesis markers. The most widely studied probiotic-derived bioactive metabolites
(exopolysaccharides (EPS), macromolecules, short chain fatty acids (SCFA and catalase) are also effective against CRC. EPS increased cell apoptosis, downregulated AKT-1, mTOR, JAK-1 pathways, inflammatory markers, cell proliferation, viability and tumour growth. Macromolecules increased Z0-1 protein level whilst reduced cell invasion and MMP-9 gene. SCFA induced cell apoptosis and pH-mediated switch between apoptosis and necrosis, whilst reduced cell viability, proliferation and inhibited Wnt-β/ catenin pathway. Catalase decreased hydrogen peroxide level and increased catalase activities. Generally, clinical evidence of probiotics and their bioactive metabolites against CRC remains limited and their strain-dependent effects pose challenges for clinical applications.