National Defence University of Malaysia
Recent publications
This study examines fatigue damage progression in Aluminium 6061 using acoustic emission (AE) analysis combined with continuous wavelet transform (CWT). Despite the widespread use of Aluminium 6061 in the automotive and aerospace industries, existing fatigue monitoring methods lack the precision needed to detect early damage progression under variable loading conditions. Current approaches do not fully utilise the combined potential of AE and wavelet energy analysis to provide real-time insights into fatigue behaviour. AE signals were captured under constant amplitude and block spectrum loading to analyse transient damage events. CWT was employed to decompose the AE signals into time–frequency components, enabling precise identification of the fatigue damage stages. By extracting wavelet coefficients and energy, the study effectively illustrates damage accumulation patterns. The analysis revealed a rate of over 95% accuracy in correlating the AE signals between the time and frequency domains, with power spectral density (PSD) and CWT energy correlations exhibiting a minimum error margin of 5%. These results highlight the capability of CWT to detect fatigue events and accurately predict fatigue life. The findings provide a robust framework for understanding fatigue behaviour under variable loading conditions, offering an advanced approach for predictive maintenance and structural health monitoring.
This study investigates the response of cylindrical metal bars, acting as plungers, subjected to close-in blast loads and compressed against cylindrical metal bars placed at the opposite end. Utilizing ABAQUS software, the study aims to replicate high-speed dynamic events related to impact and stress wave propagation. Full-scale experimental tests were conducted to validate the simulation results, focusing on deformation behavior and dimensional changes. Findings indicate that plunger response varies with length, with shorter plungers allowing more energy to propagate through, reaching further toward the target. The maximum stress was observed at the plunger surface upon explosion, with deformation patterns resembling the mushrooming effect seen in the Taylor impact test. The simulations showed an average initial stress of 12,512.24 MPa, with a significant stress loss of 89–94% at the rear end, and an additional 50% loss as stress propagated into the target. Validation results demonstrated that the plunger's deformation and target's deformation in the simulation closely matched the experimental data, confirming the accuracy of the simulation model. These results provide valuable insights for designing resilient structures and optimizing manufacturing processes involving blast load compaction. Future research will explore the use of different materials and configurations to further understand stress wave propagation and its effects on material deformation under dynamic loading conditions.
Lignocellulosic biomass such as sugar palm fiber (SPF) has been applied in industrial applications owing to its abundantly availability, renewability, biodegradability, durability, thermal stability, and high specific strength. SPF typically ranges in diameter from 115.4 to 596.2 µm and comprises 37.3 %–66.5 % cellulose, 4.7 %–21.0 % hemicellulose, 18.9 %–46.4 % lignin, and 0.9 %–6.3 % extractive. Additionally, treatment was proved to significantly affect the physical, chemical, mechanical, thermal, and morphological properties of the SPF. Examples of treatments include alkali, silane, ionic liquid, and acid hydrolysis. Based on the findings, treated SPF has smoother fiber surface, smaller diameter, higher tensile modulus, and tensile strength than untreated SPF. Regarding thermal stability, researchers have found conflicting results, with some finding that untreated SPF has higher thermal stability and initial degradation temperatures due to silica deposition and vice versa. Appropriate treatments for SPF could improve their fiber topography and wettability for better interfacial bonding that contributes to exceptional mechanical properties compared to untreated SPF‐reinforced polymer composites.
Introduction Congenital malformations (CMs) are a leading cause of infant morbidity and mortality worldwide, with prevalence rates varying across regions. In India, congenital anomalies contribute significantly to neonatal and under-five mortality. Understanding maternal knowledge and awareness of CMs and their preventable risk factors is crucial for effective intervention strategies. This study aims to assess the knowledge and awareness of CMs amongst pregnant women in India and identify factors influencing their understanding of risk factors and preventive measures. Materials and Methods A hospital-based cross-sectional study was conducted amongst 151 pregnant women attending antenatal clinics. Data was collected using a structured questionnaire covering sociodemographic details, knowledge of CMs, risk factors and preventive strategies. Statistical analysis was performed using SPSS v25, employing descriptive statistics, Pearson correlation and multivariate regression analysis. Results Most participants (64.2%) were aged 26–35, and 52.7% had completed high school. Overall, 89.4% demonstrated a moderate level of knowledge about CMs. While most participants (92.1%) recognised alcohol consumption as a risk factor, misconceptions persisted, with 65.6% believing supernatural forces could cause congenital disabilities. Higher education levels and antenatal care attendance were significantly correlated with better knowledge of CMs and their prevention. Conclusion Despite moderate awareness, knowledge gaps and cultural misconceptions remain prevalent. Strengthening educational interventions, promoting antenatal counseling and addressing misinformation can enhance maternal understanding of CMs, ultimately reducing neonatal morbidity and mortality in India.
This review discusses an evaluation of the problems of internet and smartphone addiction of children and teens, probing self-regulation issues linked to the rapid increase in the use of digital devices. Information was sourced through a literature review conducted on multiple databases, including PubMed, Scopus, Web of Science and PsycINFO. The review has also presented a cross-country comparison of the addiction rates to focus on unattended forms of addictive behaviour, with special reference to social media and gaming addiction. The report makes a further distinction by outlining the use of online gaming among boys and mobile phones for socialisation among girls as an indicator of gender-based patterns of addiction. These phenomena, when further interrogated, show a set of factors ranging from the availability of technology, lack of parental guidance, cultural setting, issues with emotional self-regulation and most relevant, addiction-related issues and mental health problems. Their negative manifestations were psychological in nature, mostly depression and anxiety, as well as physical in nature, including sleep disorders and other ergonomic illnesses. The treatment strategies listed in the document include less active forms, such as psychological manipulation and counselling, and more active forms such as engaging in sports, practicing digital disconnection, meditation and other mindfulness-based activities together with parents. Moreover, by prioritising education, awareness and community involvement, we can mitigate the adverse effects of digital addiction can be mitigated to promote healthier technology use among young people.
Introduction Medical students use mobile phones (MPs) for communication, academic purposes and social activities. However, their frequent handling and rare disinfection make them potential vectors for microbial contamination, posing a risk of pathogen transmission, particularly in healthcare settings. Materials and Methods This cross-sectional study investigated the hygienic aspects of MP usage amongst 151 medical students at the National Defence University of Malaysia (NDUM). Data were collected using a self-administered online questionnaire assessing phone usage, hygiene practices and infection control awareness. Descriptive and multiple linear regression analyses were conducted. Results Most students (93.4%) used cover protectors, and 59.6% used MPs for more than 6 h daily. Poor hygiene practices were prevalent, with 66.2% rarely washing their hands after using MPs, 60.9% seldom cleaning MPs and 41.72% cleaning them only after more than a week. The most common cleaning methods were wet wipes (39.74%) and alcohol wipes (24.50%). Female and non-Malay students exhibited significantly better MP hygiene practices than their counterparts. Amongst clinical students, 96.7% used the same MP at home and in hospitals, while 41.0% rarely cleaned MPs after hospital use, increasing the risk of cross-contamination. Conclusion The study highlights suboptimal MP hygiene practices amongst NDUM medical students, emphasising the need for improved infection control education. Incorporating MP hygiene into infection control training and promoting regular disinfection practices are crucial for mitigating microbial transmission risks in healthcare environments.
This scoping review investigates the innovative strategies the Ministry of Health (MoH) Malaysia implemented to enhance sexual and reproductive health (SRH) services for adolescents, a demographic facing unique health challenges. The primary objective is identifying and evaluating these strategies to inform future policy and practice. A systematic search was conducted across multiple databases, including PubMed, Scopus and Google Scholar, focusing on studies published in the last 10 years about adolescents’ SRH services in Malaysia. The review identified several effective interventions, including community engagement initiatives, educational programmes tailored for adolescents and integration of digital health technologies, all aimed at improving access and awareness amongst young individuals. Results indicate that these multifaceted approaches have positively impacted adolescents’ health outcomes by fostering informed decision-making and reducing barriers to accessing services. The findings underscore the importance of continued innovation and adaptation of strategies to meet the evolving needs of this population. Furthermore, this study contributes valuable insights into the Ministry’s efforts. It offers a framework for future research and policy development, emphasising the necessity of collaborative approaches involving stakeholders at various levels. The ongoing commitment to enhancing SRH services for adolescents in Malaysia is critical for improving their overall well-being and ensuring that they have the knowledge and resources to make informed choices.
Introduction The etiology of malocclusion is multifactorial, involving both genetic and environmental influences. The literature has shown that neither a single entity, hereditary or genetic factors, nor ecological factors alone are responsible for causing malocclusion; furthermore, constant thumb-sucking and pacifier use, bony anomalies, congenitally missing teeth, oral injury, mouth breathing, etc., often cause malocclusion. Participants were selected from those who reported to the outpatient department of the Karnavati School of Dentistry in Gandhinagar, Gujarat, India, indicating a clinic-based sampling method. Both hereditary and environmental factors were equally considered as causative factors. This research aims to determine how craniofacial patterns associated with class II division 2 malocclusion are inherited from parents to their children through a pedigree analysis. Methods Patients diagnosed with class II division 2 malocclusion underwent thorough intraoral and extraoral assessments. Cephalometric tracings were included in the study after meeting the established inclusion and exclusion criteria. Family trees were created and analyzed using Cyrillic Software. Results A stronger correlation was found between patients and their fathers regarding skeletal and dental measurements. In contrast, the correlation coefficients for skeletal parameters between patient-mother pairs showed highly significant correlations, whereas no statistically significant correlation was found for dental parameters. Conclusion The morphogenetic expression in this study revealed that class II division 2 malocclusion exhibited sexual dimorphism for this specific category. Genetic counseling for parents can aid in early diagnosis and the development of prevention strategies. Mutations that are likely to occur due to the presence or absence of a particular gene or group of genes can be avoided if the prevalence of the specific gene associated with that condition is known.
Carbon-based sensors utilize materials like graphene and carbon nanotubes (CNTs) to achieve high sensitivity and flexibility. They are ideal for detecting various substances, from gases and chemicals to biological molecules. These sensors are increasingly used in diverse applications such as environmental monitoring, medical diagnostics, wearable devices, and industrial safety. Over the years, CNT-based sensors have offered exceptional conductivity and mechanical properties but have been hindered by humidity, affecting the performance of electrical measurements. Consequently, the aim of this study is to investigate the effect of various polar functional groups (e.g., –OH, –COOH, –F, and –NH2) on the wettability of CNT nanocomposites, employing bacterial cellulose (BC) as a binder. Upon the synthesis of CNT/BC (BXC) and functionalized BXC (BXC-OH, BXC-COOH, BXC-F, and BXC-NH2), their chemical structural and optical properties were studied by UV-Visible, Fourier transform infrared (FTIR), and Raman spectroscopy. Crucially, the wettability behavior of nanocomposites was evaluated using water by measuring the liquid contact angles with a goniometer. The analysis revealed the influence of polar functional groups on the properties of the functionalized BXC nanocomposites. In addition to color changes during sheet fabrication, defects in the nanocomposite caused diameter changes (ΔD) ranging from approximately 26 to 60%, affecting the reflectance intensity (ΔI r) by 32–95%. While different functionalized BXC nanocomposites exhibit varying OH-group characteristics in their FTIR spectra, Raman spectroscopy data demonstrate that BXC-OH has the lowest I D/I G ratio, indicating defect levels around 0.80. Notably, the functionalized BXC nanocomposites exhibited hydrophilic properties and showed a distinct difference in contact angle (45.01°–74.57°) and spreading speed compared to BXC (97.98°) when liquid droplets were introduced. However, BXC-OH exhibited a unique behavior compared to the other functionalized BXC nanocomposites. Its dynamic contact angle (DCA) measurements showed that the adhesion force between the water and the nanocomposite surface remained constant over time. This suggests a weaker interaction, which contrasts with the varying hydrophilic properties observed in the other functionalized BXC materials. Hence, investigating DCA enhances the development of CNT-based sensors by effectively addressing humidity-related issues, thereby improving the performance of application technologies, especially in electrochemical sensors, filtration systems, and water-repellent coatings.
Knowledge graphs, prevalent in a multitude of domains, have gained significant traction over the years. However, these graphs, often created from noisy sources using imperfect methods, suffer from inaccuracies, inconsistencies, and incompleteness. The imperative to rectify and supplement these issues is frequently addressed by costly domain-expert-based strategies or learning-based techniques, which can prove unreliable in noisy environments. Real-world data, with its inherent objectivity and implicit knowledge, can serve as an external source of knowledge. The ready availability of big data today presents an opportunity for improving knowledge graphs. Yet, the challenge of extracting latent information from such data has often deterred the inclusion of numerical data in current research. This paper introduces a pioneering approach that leverages external numerical data to enhance knowledge graph quality. The proposed method commences by mining statistical relationships, such as correlation and causality from the data. Following a thorough analysis of causal patterns and an evaluation of relation strengths, it identifies and eliminates redundant knowledge. The empirical results from numerous experiments validate the efficacy of our approach. The proposed method outperforms existing learning-based methods, demonstrating superior accuracy and stability in knowledge correction.
High-performance electrolytes are crucial for advancing energy storage devices such as batteries and supercapacitors. One approach to enhancing the performance of electrolytes is the incorporation of redox additives, which introduce the redox reactions which will be helpful in improving the charge-storage capabilities of the energy storage device. In the present work, non-redox and redox-additive biopolymer electrolytes are demonstrated. The non-redox biopolymer electrolytes (BPEs) comprise a host polymer cellulose acetate (CA) and ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImTFSI) in which redox-additive potassium iodide (KI) is further incorporated to prepare the redox-additive biopolymer electrolytes (RBPEs). The solution cast technique has been used to synthesize electrolyte systems with different ionic liquid concentrations and redox-additive concentrations. The prepared polymer electrolyte films are characterized for their structural, electrical, and dielectric properties using different characterization tools such as X-ray diffraction, Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, linear sweep voltammetry, and Wagner polarization technique. The optimized non-redox and redox-additive biopolymer electrolyte film shows a maximum ionic conductivity of ~ 3.25 × 10⁻⁵ S cm⁻¹ and ~ 1.05 × 10⁻⁴ S cm⁻¹, respectively, and both films are stable up to ~ 2.7 V. Further, two supercapacitor cells (Cell#1 and Cell#2) are fabricated utilizing activating carbon based electrode materials and BPE-2 and RBPE-240 as electrolytes respectively. The Cell#1 and Cell#2 show a specific capacitance of 49.28 F g⁻¹ and 215.16 F g⁻¹ at a current density of 0.5 A g⁻¹, and a specific energy of 6.84 Wh kg⁻¹ and 29.88 Wh kg⁻¹ at power densities of 899 W kg⁻¹ and 820 W kg⁻¹ respectively.
Introduction Obsessive-compulsive disorder (OCD) imposes a considerable impact on day-to-day functioning. Many people experience insufficient symptom relief even after taking the optimum dose of OCD medications. Reduced levels of folic acid and vitamin B₁₂, along with elevated homocysteine (HCY), have been suggested as possible factors in the persistence of obsessive-compulsive (OC) symptoms. This study investigated how supplementation of vitamin B₁₂, folic acid, and selective serotonin reuptake inhibitors (SSRIs) affects OC symptoms and related biochemical markers. Methods A comparative study enrolled 72 OCD patients. For eight weeks, the conventional treatment group received SSRIs or other anti-obsessive medication. In contrast, the nutrient-supplemented group received supplements of vitamin B₁₂, folic acid, and SSRIs. Micronutrients HCY, folic acid, and vitamin B₁₂ were measured at baseline and after eight weeks. Besides, the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) was applied to assess the severity of OCD symptoms at the baseline, four-week, and eight-week visits. Results Group A (conventional treatment with nutrient supplement) showed significant improvements in vitamin B₁₂, blood folic acid, and reductions in HCY levels compared to Group B (conventional treatment). However, no substantial differences in insight levels were observed between the groups. Both groups exhibited decreased Y-BOCS scores, indicating a reduction in OCD symptoms; however, the improvements in Group A (conventional treatment + nutrient supplement) were statistically significant. Conclusions When taken with SSRIs, vitamin B₁₂ and folic acid supplements seem to improve OCD patients’ clinical results. These results imply that this supplementation could be a useful therapeutic adjunct
The periodontium is one of the most complex tissues in the body, consisting of a hierarchical blend of soft and hard tissues. Its complex architecture makes treating and regenerating disease-damaged periodontal tissues a persistent challenge in biomedicine. Three-dimensional (3D) bioprinting represents a transformative approach to tissue engineering, offering promising advancements in treating and regenerating periodontal disease. This innovative technology enables the precise fabrication of complex, patient-specific tissue structures, facilitating the repair and restoration of damaged periodontal tissues, including the gingiva, bone, and periodontal ligament (PDL). By utilizing biocompatible materials such as living cells, hydrogels, and growth factors, 3D bioprinting has the potential to create functional, biologically integrated constructs that can mimic the natural architecture of periodontal tissues. However, translating these advancements into clinical applications remains a challenge. Emerging technologies like bioprinting have been developed to address some limitations of traditional tissue engineering methods. This review explores the current state of 3D bioprinting technology, its application in periodontal disease treatment, and the challenges associated with scaling up this technology for clinical use. Additionally, it discusses the future implications of bioprinting for personalized medicine, offering a new frontier for regenerating periodontal tissues and improving patient outcomes in oral health. Integrating 3D bioprinting into periodontal regenerative therapies could revolutionize clinical practices, offering more effective, tailored, and sustainable solutions to address the challenges of periodontal disease
Recent advancements in nanotechnology have expanded the applications of cellulose nanoparticles (CNPs) isolated from various types of biomass waste like oil palm empty fruit bunches. These applications are particularly enhanced by incorporating nanoparticles or polymers. However, a significant challenge in synthesizing CNP-based nanocomposites lies in the selection of appropriate synthesis methods, as ineffective techniques can result in poor compatibility between nanoparticles. To overcome this issue, surface modification through carboxymethylation has emerged as an effective strategy. This process introduces anionic groups (−CH2COONa⁺) onto the CNP surface, producing anionic nanocellulose particles (ACNPs) that act as capping agents to enhance nanoparticle incorporation. Despite these advancements, the optimum reaction time for isolating ACNPs from CNPs, particularly nanocrystalline cellulose, remains underexplored. This study investigates the effect of varying carboxymethylation reaction times (30 min, 2, 4, 6, and 8 h) on the synthesis of ACNPs. Characterization techniques, including Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, transmission electron microscopy, zeta potential analysis, thermogravimetric analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), were employed. The results indicate that a reaction time of 4 h is optimal for carboxymethylation. ACNPs synthesized at this duration exhibit good dispersion, improved thermal stability, and a high zeta potential value (−41 mV) compared to CNPs (−25 mV). FTIR analysis reveals new peaks at 1,564, 1,432, and 1,321 cm⁻¹, corresponding to the carboxyl, methyl (−CH2), and hydroxyl groups of the carboxymethyl group (−CH2–COONa), respectively. Additionally, XPS results show a high concentration of Na⁺ ions in ACNPs synthesized at 4 h. Beyond this reaction time, Na⁺ concentration decreases.
Obesity among children has emerged as a worldwide health issue due to childhood obesity becoming a pandemic, and it is often linked to various illnesses, fatal outcomes, and disability in adulthood. Obesity has become an epidemic issue in both developed and developing countries, particularly among youngsters. The most common factors contributing to non-communicable diseases (NCDs) are unhealthy eating habits, deskbound games, avoidance of physical activity-requiring activities, smoking, alcohol usage, and other added items. All these factors increase NCDs, including obesity, resulting in various morbidities and early death. Additionally, childhood obesity has psychological, emotional, cognitive, societal, and communicative effects. For example, it raises the possibility of issues related to physical appearance, self-esteem, confidence level, feelings of isolation, social disengagement, stigma, depression, and a sense of inequality. Children who consume more energy-dense, high-fat, low-fiber-containing food than they need usually store the excess as body fat. Standardizing indicators and terminology for obesity-related metrics is critical for better understanding the comparability of obesity prevalence and program effectiveness within and between countries. The underlying variables must be altered to reduce or avoid harm to the target organ in children. As a result, reducing childhood obesity is a considerable public health goal for the benefit of society and the long-term well-being of individuals.
Antimicrobial resistance (AMR) is one of the biggest problems facing the scientific and medical communities. According to WHO, this growing issue might make once-effective antibiotics obsolete and pose a substantial risk to public health. Estimates indicate that multimillion deaths were either directly or indirectly caused by AMR, making it one of the most substantial risks to public health and development in the world. The issue of AMR is primarily caused by healthcare workers’ excessive and inappropriate use of antimicrobial agents. Dentists are believed to prescribe a considerable portion of all antibiotics globally. The emergence of AMR, its causes, and its effects on human health are examined in this article, with special attention to dental offices and medical facilities. It draws attention to the rising issue of antibiotic overprescription and abuse, particularly in low- and middle-income countries, where improper antibiotic use is an everyday practice around the globe. The article discusses the role of antimicrobial stewardship programs and the importance of implementing precise, evidence-based practices in preventing AMR. Since antibiotic abuse in livestock greatly accelerates the spread of resistance, the role of antibiotics in animal agriculture is also investigated. To address AMR, the paper highlights the necessity of a global, coordinated response that bolsters surveillance systems, cuts back on needless antibiotic use, and expands access to alternative treatments. Recent research has called into question the efficacy of preventive antibiotic medication in these situations. According to other researchers, it might not help avoid surgical site infections. However, other experts say disrupting deeper tissues and local mucosal defenses during an intraoral surgical operation may raise the risk of infection even when antibiotics are used.
Introduction: Work-related musculoskeletal disorders (WMSDs) are typical health issues that have considerably caused disability among staff across industrial fields. Although aircraft mechanics and maintenance technicians reported significant workplace injuries, injury risk exposure evaluations of the various tasks in the industry are limited. Objective: The current study determined WMSD or pain prevalence and ergonomic risks faced by military aircraft personnel. Methods: A total of 40 military aircraft maintenance staff from the engineering department were selected according to the simple random sampling method. Data collection method was carried out with a self-administered questionnaire, Cornell Musculoskeletal Discomfort Questionnaire (CMDQ), while the ergonomic risk factor level was assessed according to the Quick Exposure Check (QEC) method. QEC assessment method was done by both observer and participants. The preliminary action levels for the QEC score were also analysed. Results: Based on the 12-month WMSDs prevalence, the shoulder and knees (90%, n = 36), lower back (77.5%, n = 31) and neck (70%, n = 28) recorded the highest body discomfort and pain percentages. The QEC results revealed that the engine bay area required immediate changes (red) 72%, while five other sites necessitated prompt alterations (orange) range between 51% and 70%. Conclusion: Military aircraft maintenance personnel, particularly individuals working in the engine bay, are exposed to notable risks of shoulder, wrist, back (static) and neck region injuries, which could affect their well-being and productivity. Consequently, aviation maintenance personnel should perform routine physical exercises as an alternative to ergonomic interventions.
N‑acetylcysteine (NAC) is becoming more and more popular medication in the management of mental health conditions. NAC antiinflammatory, antioxidant and glutamate transmission properties, currently being explored for the therapeutic intervention of neurological conditions, e.g. anxiety, depressive disorders, post‑traumatic stress disorder, obsessive‑compulsive disorders, bipolar disorders and schizophrenia. Clinical studies for many psychiatric diseases have yielded contradictory findings, despite the fact that there is a wealth of preliminary data and intellectual support for the application of NAC in the treatments of many of these illnesses. The most of the research studies have proven insufficient and too briefly explored. More research are required to established NAC efficacy, appropriate indication and adverse drug reactions.
A novel kappa-carrageenan derivative, glutaryl kappa-carrageenan (G-κCar) was successfully produced via nucleophilic substitution reaction. The introduction of glutaric anhydride (GA) into the kappa-carrageenan (κCar) matrix had markedly altered its chemical and electrochemical properties. Elemental analysis showed that the GA substitution led to an increased oxygen percentage in G-κCar as compared to pure κCar. The highest degree of substitution obtained was 4.14 in 3 gGA-κCar/48 h synthesized sample. The successful substitution of GA molecule into κCar polymeric chain was confirmed by the FTIR analysis based on the formation of a new carbonyl (C=O) bond in the G-κCar spectra. The ¹H-NMR analysis further proved the GA substitution by the appearance of new multiple resonance peaks at δ = 1.70–2.75 ppm, which belonged to the characteristic signals of protons in the anhydride group. TGA thermograms showed lower degradation temperature in the synthesized G-κCar due to disruption of both intermolecular and intramolecular hydrogen bonds in the G-κCar polymeric chains. The substitution of GA also improved the ionic conductivity of G-κCar up to 4.63 × 10⁻³ S cm⁻¹ at ambient temperature. Cyclic voltammetry plots demonstrated that the 3 gGA-κCar/48 h sample had a larger background current than κCar which indicated that the synthesized 3 gGA-κCar/48 h biopolymer had an improved effective surface area. Linear sweep voltammetry (LSV) analysis revealed the increased electrochemical potential in G-κCar as compared to the pristine κCar. The highest potential obtained was 1.95 V for 3 gGA-κCar/48 h sample. The transference number for 3 gGA-κCar/48 h was calculated to be 0.98 over five continuous hours. This implied that ionic conduction in the gel was predominantly driven by ions, with the contribution of electrons being minimal and therefore negligible. This study highlighted how this functionalization enhanced the characteristics of κCar, potentially expanding G-κCar applications as a gel biopolymer electrolyte in electrochemical systems. Graphical abstract
The COVID-19 outbreak has precipitated severe occurrences on a global scale. Hence, spatial analysis is crucial in determining the relationships and patterns of geospatial data. Moran’s I and Geary’s C are prominent methodologies used to measure the spatial autocorrelation of geographical data. Both measure the degree of similarity or dissimilarity between nearby locations based on attribute values in such a way that the selection of distance techniques and weight matrices significantly impact the spatial autocorrelation results. This paper aimed at carrying out the spatial epidemiological characteristics analysis of the pandemic comparing the results of Moran’s I and Geary’s C with different parameters to gain a comprehensive understanding of the spatial relationship of COVID-19 cases. We employed distance-based techniques, K-nearest neighbour, and Queen contiguity techniques to assess the sensitivity of the different parameter configurations for both Moran’s I and Geary’s C. The findings revealed that former provided more reliable and robust results compared to the latter, with consistent results of spatial autocorrelation (positive spatial autocorrelation). The distance weight of 0.05 using the Manhattan method of Moran’s I is the recommended distance weight, as it outperformed other weight matrices (Moran’s I = 0.0152, Z-value= 110.8844 and p-value=0.001).
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Siti Zulaikha Ngah Demon
  • Centre for Defence Foundation Studies
Aye Aye Mon
  • Facuty of Medicine and Defence Health
Mohd Fahmi Mohamad Amran
  • Department of Computer Science
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