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Recent Submissions
Evaluation of Land Use Land Cover Changes in Nan Province, Thailand, Using Multi-Sensor Satellite Data and Google Earth Engine
(2023) Jiratiwan Kruasilp; Sura Pattanakiat; Thamarat Phutthai; Poonperm Vardhanabindu; Pisut Nakmuenwai
Land use and land cover (LULC) conversion has become a chronic problem in Nan province. The primary factors of changes are lacking arable land, agricultural practices, and agriculture expansion. This study evaluated the usefulness of multi-sensor Landsat-5 (LS5), Landsat-8 (LS8), Sentinel-1 (S1), and Sentinel-2 (S2) satellite data for monitoring changes in LULC in Nan province, Thailand during a 30-year period (1990-2019), using a random forest (RF) model and the cloud-based Google Earth Engine (GEE) platform. Information of established land management policies was also used to describe the LULC changes. The median composite of the input variables selection from multi-sensor data were used to generate datasets. A total of 36 datasets showed the overall accuracy (OA) ranged from 51.70% to 96.95%. Sentinel-2 satellite images combined with the Modified Soil-Adjusted Vegetation Index (MSAVI) and topographic variables provided the highest OA (96.95%). Combination of optical (i.e., S2 and LS8) and S1 Synthetic Aperture Radar (SAR) data expressed better classification accuracy than individual S1 data. Forest cover decreased continuously during five consecutive periods. Coverage of maize and Pará rubber trees rapidly expanded in 2010-2014. These changes indicate an adverse consequence of the established economic development promoted by industrial and export agriculture. The findings strongly support the use of the RF technique, GEE platform and multi-sensor satellite data to enhance LULC classification accuracy in mountainous area. This study recommended that certain informative and science-based evidence will encourage local policymakers to identify priority areas for land management and natural resource conservation.
Optimization and Kinetic Study of Phosphorus Dissolution from Primary Settled-Nightsoil Sludge
(2023) Wanida Pimpeach; Withida Patthanaissaranukool; Chongchin Polprasert; Supawadee Polprasert; Suwisa Mahasandana; Bunyarit Panyapinyopol
In this study, chemical extraction using different acid concentrations, solids concentrations, and reaction time with subsequent interactions mechanism were carried out to evaluate the potential of phosphorus (P) recovery from primary settled-nightsoil sludge (PSNS). The response surface methodology (RSM) with Box-Behnken experimental design and one-way ANOVA analysis were also employed to establish optimal P leaching conditions. The extraction efficiency relied mainly on acid and solids concentration. The second-order polynomial model was successfully developed for extracting process designs. Approximately 93% of P could effectively be extracted from PSNS of 20,000 mg/L with 0.5 M of H2SO4 at reaction time of 45 min (optimum condition). Kinetic studies showed that the pseudo-second order was fit to describe leaching of P and metals. Moreover, the rate of kinetic constants (k2) of the P, Fe, Mg, and Ca under optimum condition were found to be 0.1607, 0.1099, 0.0317, and 0.0053 g/mg·min, respectively. The 99% leaching of maximum extracted P concentration at the equilibrium (9.6673 mg/g) took place in less than one hour. The findings of a suitable simple and low-cost method P dissolution from PSNS not only provides understanding of leaching kinetics, but also helps to pave a way of recovering P from a renewable resource in the field of waste utilization.
Factors Predicting Postoperative Quality of Life among Rectal Cancer Patients in Thailand: A Retrospective Cohort Study
(2025-08-01) Iramaneerat C.; Owattanapanich N.; Riansuwan W.; Lohsiriwat V.; Prapasrivorakul S.; Iramaneerat C.; Mahidol University
Objective: The objectives of this study were to evaluate the postoperative quality of life (QoL) measures of Thai rectal cancer patients, and to determine which factors impact the QoL. Materials and Methods: We reviewed the medical records of rectal cancer patients who underwent abdominoperineal resection or low anterior resection between 2009 and 2012. We sent out Functional Assessment of Cancer Therapy – Colorectal (FACT-C) questionnaires to patients who met the criteria. The T-test, Kendall’s Tau-b, and Pearson correlation were used to select potentially significant predictors (p-value <0.1), which were then included in the multiple regression analysis to predict FACT-G (General QoL) and FACT-C (General QoL + concerns related to colorectal cancer) scores. Results: We analyzed data from 144 patients (out of 480 patients who met the criteria). The average FACT-G and FACT-C scores were 87.34 and 106.79, respectively. The factor that had a significant negative impact on FACT-G was age (t = -2.67, p = 0.008). The factors that had a significant negative impact on FACT-C were nodal status (t = -1.98, p = 0.05) and age (t = -2.66, p = 0.009). Conclusion: The postoperative QoL of Thai rectal cancer patients is similar to the QoL measures reported in a prior study. The QoL measures were found to be negatively impacted by age and lymph node status. Gender, the type of operation, presence of ostomy, location of the tumor, preoperative radiation, adjuvant chemotherapy, laparoscopic approach, duration after surgery, proximal and distal margins, tumor size, metastasis, and recurrence showed no impact on the QoL.
Association of Perineural Invasion of Adenocarcinoma in Prostate Biopsy with Pathological and Clinical Outcomes: Perineural invasion of adenocarcinoma in prostate biopsy
(2025-08-01) Rueangrong R.; Suk-Ouichai C.; Teyateeti A.; Mahamongkol K.; Tantranont N.; Rueangrong R.; Mahidol University
Objective: This study aims to evaluate the association between perineural invasion and pathological stage, including extraprostatic extension, and its impact on prognosis. Materials and Methods: A total of 149 men diagnosed with prostatic adenocarcinoma by magnetic resonance imaging/ultrasound (MRI-US) fusion-guided biopsy and radical prostatectomy between July 1, 2018 and December 31, 2019 at Siriraj Hospital were identified. Their pathological, clinical, and radiological findings were retrospectively analyzed. Patients with and without perineural invasion were compared using descriptive and inferential statistics. Results: Perineural invasion was identified in 87 of 149 patients (58.4%) and showed no significant association with baseline features (p > 0.05). However, perineural invasion was significantly associated with higher pathological T stage (pT2, pT3a, pT3b) (p < 0.001), including extraprostatic extension (pT3 disease) in univariate analysis. Multivariate analysis demonstrated a notable correlation between the pathological T stage and 2-year disease-free survival (p < 0.001). Conclusion: Perineural invasion should be carefully identified and reported in prostate biopsy specimens, due to its significant relationship with the pathological T stage, including extraprostatic extension.
IMPACT OF BASIN AMPLIFICATION FACTORS ON THE PSHA ANALYSIS IN THE CHIANG MAI BASIN (THAILAND)
(2024-01-01) Ornthammarath T.; Warnitchai P.; Poovarodom N.; Ornthammarath T.; Mahidol University
We evaluate a probabilistic seismic hazard analysis (PSHA) for the Chiang Mai basin (Thailand), to assess the impact of site response characterization on hazard estimates. The effect of a basin amplification factor introduced in NGA West 2 ground motion models (GMMs) is presented based on the available shear wave velocity profile from microtremor measurement. In addition, 1D amplification related to stratigraphic conditions is considered with the associated uncertainties, and their impact on the hazard is analyzed through a sensitivity analysis. The results provide a good comparison between empirical GMMs and a conventional study, highlighting the importance of ground amplification effects in hazard assessment.