58178 research outputs found
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EBS238-3 - FLUID MECHANICS - NOVEMBER 2008. PPKBSM, Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral (2025) EBS238-3 - FLUID MECHANICS - FEBRUARY 2025. [Teaching Resource]
No full textPPKBSM, Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral (2025) EBS418 - Petroleum Engineering. [Teaching Resource] (Submitted)
No full textPPKBSM, Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral (2025) EBS429-3 - ENVIRONMENTAL ENGINEERING FEBRUARY 2025. [Teaching Resource]
No full textForensic characterisation of black stamp pad ink and printed inks
No full textIn today’s digital age, the advancements in printing technologies have significantly simplified various tasks in daily life. However, these advancements have also led to an unfortunate consequence, which is the increase in document fraud and forgery. Distinguishing authentic documents from counterfeit ones can be challenging, particularly when relying on visual inspection alone. This study aimed to investigate the forensic characteristics of black stamp pad ink and printed inks, employing a comprehensive approach that combines multiple analytical techniques. These included microscopy, thin layer chromatography (TLC), and Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, alongside advanced multivariate statistical methods of Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). A total of nine different samples were examined. The physical examination conducted in this study revealed significant morphological differences between hand-stamped impressions and printed ink samples. TLC analysis effectively separated the ink components using a chloroform-ethanol solvent system, with high Rf values indicating that the chemical compositions of certain ink types shared similar characteristics. ATR-FTIR spectroscopy, on the other hand, provided unique molecular fingerprints of the inks. However, challenges arose due to spectral overlap in the fingerprint region, making it difficult to fully distinguish between the ink types. Despite these challenges, PCA and HCA demonstrated their effectiveness in grouping the ink samples based on their chemical compositions, revealing distinctive clusters that allowed for the identification and differentiation of various ink type
A study on fibre identification and characterization of various headscarf fabrics
No full textThis study focuses on the identification and characterisation of fibres from six types of headscarf fabrics, mainly cotton, silk, polyester, lycra, viscose, and moss crepe as potential sources of trace evidence in forensic investigations. Fibre evidence, often transferred during physical contact, plays a crucial role in linking suspects, victims, and crime scenes. Morphological tests revealed that distinct weave patterns and yarn structures significantly influence fabric behaviour, such as porosity and density, aiding in the differentiation of fabric types. Both cotton and viscose exhibited plain weaves, but cotton had a less porous fabric structure than viscose. Polyester and lycra showed dense synthetic structures. Burning tests identified fibres based on their combustion behaviour, residue formation, and odour. Lycra however shows uniqueness in the absence of hard beads although it is synthetic fibre. Moss crepe and viscose displayed mixed traits, confirming their partially synthetic origins. Solubility tests further validated fibre compositions by observing their reactions to various chemical solvents, demonstrating distinct dissolution behaviours influenced by chemical structure and environmental factors. Most fibres did not dissolve in 75% and 60% sulphuric acid, and none dissolved in formic acid, while most fibres dissolved in high-temperature 50% sodium hydroxide solutions. In conclusion, this study successfully classified and identified the six types of fibres using comprehensive fibre identification methods, enhancing their value as trace evidence in forensic application
Discrimination between beers with different best before dates using gas chromatography with mass spectrometry
No full textThe quality of beer is influenced by various factors, including its best-before
dates, which may impact its flavour, aroma, and chemical composition. This study
aimed to discriminate between beer samples from different best-before dates and
different brands using liquid-liquid extraction followed by gas chromatography with
mass spectrometry (LLE/GC-MS). In this study, beer samples from the brand
Carlsberg® were selected to represent different time points with varying best-before
dates to compare for their GC profiles. Additionally, four beer samples originated from
different brands, namely Carlsberg®, Asahi®, Heineken® and Tiger® were also
analysed and compared for their compositional differences. The GC-MS method was
optimised for solvent selection, dissolution ratio, and injection volume to maximize
detection sensitivity and accuracy, followed by the analyses of beer samples. Key
findings through GC-MS revealed that beers with varying best-before dates exhibited
distinct differences in their chemical profiles. Overall, 35 organic compounds were
identified from Carlsberg® beer sample using the proposed method. Specific profiles
for each beer set and from different brands were observed and visualised through
principal component analysis. To conclude, this study has successfully determined the
chemical profiles of beers with different best-before dates and of different brands,
allowing for forensic discrimination of stale beer sample
Development of dna aptamers for hemolysin e antigen of salmonella enterica serovar typhi towards diagnostic application
No full textThe rapid and accurate diagnosis of typhoid fever using specific biomarkers is essential for enhancing treatment outcomes and preventing disease transmission. This study aimed to develop a DNA aptamer-based detection system for Salmonella enterica serovar Typhi (S. Typhi), focusing on the hemolysin E (HlyE) antigen. Using Systematic Evolution of Ligands by EXponential enrichment (SELEX), DNA aptamers targeting the HlyE antigen were isolated and evaluated for binding affinity and specificity through enzyme-linked oligonucleotide assay (ELONA). Following SELEX, 11 aptamers were identified, and three (AptHlyE97, AptHlyE11 and AptHlyE45) were selected for further characterization. Their dissociation constants (Kd) fell within the nanomolar range, with AptHlyE97 showing the highest binding affinity at 83.6 nM, followed by AptHlyE11 at 102.2 nM and AptHlyE45 at 119.3 nM. Specificity tests demonstrated that these aptamers could effectively distinguish S. Typhi HlyE from other bacteria, including Salmonella Paratyphi A (P<0.001), Salmonella Paratyphi B (P<0.001), Shigella flexneri (P<0.001), Klebsiella pneumoniae (P<0.001) and Escherichia coli (P<0.001). Molecular docking analysis further supported these findings, with AptHlyE97 displaying the highest binding energy (-15.5 kcal/mol). Molecular dynamics simulations confirmed the aptamer-antigen stability, with a root-mean-square deviation (RMSD) of ~2.0 Å during 100 ns simulations. AptHlyE97 was subsequently used to develop an electrochemical aptasensor as a proof-of-concept diagnostic tool. The aptasensor was constructed by immobilizing AptHlyE97 onto a screen-printed gold electrode (Au-SPE) via thiol conjugation, with potassium ferricyanide and ferrocyanide employed for signal detection. The aptasensor demonstrated excellent diagnostic performance, achieving 100% sensitivity and 85.7% specificity in serum sample testing. Additionally, it exhibited a strong linear response with a limit of detection (LoD) of 0.158 ng/mL. This study presents a novel aptamer specific against HlyE antigen of S. Typhi and aptamer-based diagnostic platform for the efficient and selective detection of S. Typhi HlyE antigen. The high sensitivity, specificity and low detection limit of the developed aptasensor highlight its potential for advancing point-of-care diagnostics, particularly in resource-limited settings. This innovation lays a solid foundation for improving typhoid fever detection and management, offering a promising tool for community-level disease monitoring and contro
The relation between sarcopenia, physical activity, and cognitive function in community-dwelling older adults in Malaysia: A cross-sectional study
No full textThis study examines the prevalence of sarcopenia among community-dwelling older adults in Malaysia and its association with cognitive function and physical activity levels. Community-dwelling older adults aged 60 y and above in high older persons ratio towns were recruited. Sarcopenia was assessed using the Skeletal Muscle Index (SMI), handgrip strength (HGS), and Short Physical Performance Battery (SPPB) based on the Asian Working Group for Sarcopenia (AWGS2) criteria. Participants were considered sarcopenic if they exhibited low muscle mass and strength/performance. Participants with all three low muscle mass, strength and performance criteria have severe sarcopenia while those with sufficient muscle mass but low strength or performance have possible sarcopenia. Cognitive function was assessed using the 1) Montreal Cognitive Assessment (MoCA) to screen for mild cognitive impairment, 2) Trail Making Test (TMT-A and TMT-B) to evaluate cognitive processing speed and flexibility, and 3) Digit Symbol Substitution Test (DSST) to assess information processing ability. Physical activity (PA) levels were measured using the Physical Activity Scale for the Elderly (PASE) that categorised PA levels as sedentary, light, and moderate-to-high. Statistical analyses were performed using R software version 4.3.0. From the 831 participants screened, a total of 677 older adults (average age 68.2 ± 6.0 y, 61.3% women) were classified as no sarcopenia (n=58, 8.6%), possible sarcopenia (n=576, 85%), sarcopenia (n=25, 3.7%) and severe sarcopenia (n=18, 2.7%). Results showed that a higher proportion of women, 5.8% (n=24) were sarcopenic compared to men, n=1 (0.4%). Overall,
sarcopenic and severe sarcopenia men and women were shorter in stature and have
smaller arm and calf circumferences compared to those with no or possible sarcopenia.
Most sarcopenic men and women have normal HGS but outcomes for the 4-m gait
speed was poor (<0.9 m/s). About 54% participants engaged in moderate-to-high
levels of PA, but PA levels declined with increasing sarcopenia severity. Correlation
analysis showed that age, gender, and nutritional status were significantly associated
with sarcopenia (p<0.05), but not PA levels. Regression findings showed that age,
gender, nutritional status, PA levels, and cognitive function collectively influenced
sarcopenia risk (R² = 0.54). These findings indicate the need for early intervention
through exercise programs, balanced nutrition, and continuous healthcare support to
reduce the risk of sarcopenia and cognitive decline in older Malaysian adults. (370
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