Mahidol University's Institutional Repository
คลังสารสนเทศสถาบันของมหาวิทยาลัยมหิดล
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Recent Submissions
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Autopsy study of alcohol-associated unnatural deaths in Thailand, 2007–2019
(2023-01-01) Sribanditmongkol P.; Mahidol University
Background: To date, there have been no major studies of alcohol-associated unnatural deaths in Thailand or South East Asia. Thailand leads South East Asia in per capita alcohol consumption. The objectives of this study were to determine the incidence of alcohol-associated unnatural deaths in Thailand and their relation to post-mortem blood alcohol concentration (BAC); to investigate correlations between BAC and selected demographic variables; and to evaluate the incidence of co-use of alcohol and illicit substances. Methods: We conducted a retrospective register-based study of alcohol-investigated unnatural deaths in Thailand for the period 2007–2019. The core study sample (n = 77,006) was derived from a Thai government computerized database of unnatural-death autopsies. Results: Of the total autopsy sample 32.49% was alcohol positive (BAC ≥0.20 g/L). The rate at which male autopsy cases were alcohol positive (35.52%) was approximately twice that of female autopsy cases (16.62%), with males having significantly higher median BAC levels, 1.64 and 1.31 g/L, respectively. The incidence of female alcohol-positive cases with extremely high BACs (≥3.50 g/L) was comparable to that of male alcohol-positive autopsies. The rates at which victims of accidents, homicides, and suicides were alcohol positive were 42.44%, 38.81%, and 33.25%, respectively. Drowning fatalities had the highest rate of alcohol detection (49.12%) and the highest median BAC (2.47 g/L). The next highest rate (48.47%) was among road traffic fatalities (RTFs, BAC 1.92 g/L), which accounted for about one-half of all RTFs and one-third of all alcohol-positive autopsies. Of the total alcohol-positive population, 8.33% tested positive for illicit substances, most commonly methamphetamine/amphetamine. Conclusions: BAC results for the majority of male and female alcohol-positive victims exceeded the generally accepted threshold for Heavy Episodic Drinking (0.8 g/L) and provided a rare BAC-documented (≥3.50 g/L) example of gender parity in the incidence of heavy alcohol consumption. The median BAC value for alcohol-positive RTFs (1.92 g/L) was about 10% higher than in studies in most other countries and about four times greater the Thai legal limit for motor-vehicle operation (0.50 g/L).
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Remineralization Effect of Calcium Glycerophosphate in Fluoride Mouth Rinse on Eroded Human Enamel: An in Vitro Study
(2023-01-01) Torsakul P.; Mahidol University
Aims and Objectives: The aim of this in vitro study was to evaluate the remineralization effect of calcium glycerophosphate (CaGP) in fluoride mouth rinse on permanent enamel eroded by a soft drink. Materials and Methods: Forty sound permanent premolars were embedded in self-curing acrylic resin and immersed in Coca-Cola to create erosive lesions. The teeth were divided into four groups (n = 10): Group I artificial saliva; Group II sodium fluoride; Group III sodium fluoride + sodium monofluorophosphate; and Group IV sodium monofluorophosphate + CaGP. The specimens in the assigned groups underwent pH cycling for ten days. The baseline, after erosion, and after remineralization surface microhardness (SMH) values were determined. The data were analyzed by one-way analysis of variance (ANOVA). The mean SMH value between groups and one-way repeated measures ANOVA for the mean SMH value within each group and Bonferroni's for multiple comparisons at a 95% confidence level were determined. The average SMH was used and calculated as the percentage recovery of SMH. Results: After being eroded by the cola soft drink, the mean SMH values in all groups were significantly decreased. After remineralization, Group I had the lowest %SMHR. The %SMHR of Groups II, III, and IV were significantly higher than Group I (P < 0.001). However, there were no significant differences among Groups II, III, and IV (P > 0.05). Conclusions: Fluoride mouth rinse with and without CaGP showed similar efficacies in remineralizing eroded permanent enamel.
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Examining Student Behavioral Intention of Superstar Learning System by Extending Its Technology Acceptance Model
(2022-01-01) Yu Z.; Mahidol University
Superstar Learning System, designed and developed by Superstar Company, is a learning platform where teachers and learners may have access to plentiful educational resources and interact with each other. Behavioral intention related to this platform has not been explored although many researchers have examined its use in education. A random sampling technique and a questionnaire survey were adopted to collect data to complement this missing link in literature. This study revealed numerous influencing factors of behavioral intention such as performance expectancy, effort expectancy, lecturer influence, peer influence, user innovativeness, interface simplicity, and multiple functions. It also extended the extended technology acceptance model (TAM) by involving more influencing constructs (i.e., lecturer and peer influences, user innovativeness, interface simplicity, and multiple functions). Future research could adopt inter-disciplinary research methods to examine Superstar Learning System-based behavior intention of learners.
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Salivary Oxidative Stress Biomarkers in Thai Adolescents and Young Adults with Type 1 Diabetes Mellitus: A Cross-Sectional Study
(2023-01-01) Aroonrangsee T.; Mahidol University
Aims and Objectives: The primary objectives of this study were to compare salivary oxidative stress (OS) biomarker levels in patients with type 1 diabetes mellitus (T1DM) and without T1DM (non-T1DM) and evaluate the relationships between diabetes, periodontal status, and OS biomarker levels. Materials and Methods: Twenty patients with T1DM and 20 age-matched patients without T1DM were enrolled. All participants were 15-23 years of age and had permanent dentition. Unstimulated whole saliva was collected in a sterile test tube before examination of clinical periodontal parameters, including bleeding on probing (BOP). Salivary levels of OS biomarkers - malondialdehyde, protein carbonyl, total oxidant status (TOS), and total antioxidant capacity - were determined using oxidative and antioxidative assays followed by spectrophotometric measurement at 375-532 nm. The relationships between diabetes, periodontal status, and OS biomarkers were analyzed using multiple linear regression. Results: TOS was significantly lower in the T1DM group compared with the non-T1DM group (5.06 ± 0.39 vs. 6.44 ± 0.51 μmol H 2 O 2 Eq/l, P = 0.035). After adjusting for confounding factors (age, gender, BMI, clinical periodontal parameters, BOP, or diabetes status accordingly), the multiple linear regression showed that T1DM was significantly associated with a reduction of TOS level (P = 0.008). The BOP > 30% group showed a significant correlation with increased TOS levels compared with the BOP ≤ 30% group (P = 0.002). No relationship was found between OS biomarkers and HbA1c levels. Conclusion: Salivary TOS levels were related to both diabetes status and the extent of gingival inflammation. Further studies to elucidate the role of OS in relation of periodontal disease and T1DM are required.
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Graphene oxide-alginate hydrogel-based indicator displacement assay integrated with diaper for non-invasive Alzheimer's disease screening
(2023-12-31) Boobphahom S.; Mahidol University
Pyrocatechol violet/copper ion-graphene oxide/alginate (PV/Cu2+-GO/Alg) hydrogel was fabricated and applied as a colorimetric sensor for monitoring urinary cysteine via an indicator-displacement assay (IDA) and Cu2+-cysteine affinity pair. The hydrogel-based sensor was formed by Ca2+ cations cross-linked PV/Cu2+-GO/Alg. The morphologies of hydrogel were characterized by field-emission scanning electron microscopy with energy-dispersive X-ray spectroscopy and Fourier-transform Raman spectroscopy. Incorporating GO into the hydrogel improved its uniformity of porosity, large surface area, and compressive strength, leading to amplified colorimetric signals of the hydrogel sensor. Under optimal conditions, this sensor offered a linear range of 0.0–0.5 g/L with a detection limit of 0.05 g/L for cysteine without interfering effects in urine. Furthermore, this hydrogel-based sensor was applied for urinary cysteine detection and validated with laser desorption ionization mass spectrometry. This platform could be used to determine cysteine at its cutoff (0.25 g/L) in human urine, which was distinguishable between normal and abnormal individuals, to evaluate an early stage of Alzheimer's disease. Eventually, this system was integrated with diapers for a wearable cysteine sensor.