Chiang Mai Journal of Science

Soil salinization is a severe soil degradation process which represents a critical ecological challenge, threatening the sustainable development of agriculture in the Kashgar oasis region of Xinjiang. Therefore, the timely and efficient monitoring and the accurate estimation of soil salinity are highly imperative for the prevention and management of soil salinization.The study presented in this paper involves the development of a new soil salinity inversion model based on the TabNet deep learning algorithm using remote sensing data and environmental variables. The model outperforms common ensemble learning algorithms based on decision trees. This improvement is achieved through the use of attention mechanism and the deep learning architecture in TabNet. In addition, the novelty of the proposed soil salinity inversion model lies in its use of deep learning to construct an inversion model for salinization. The feature variable dataset was initially constructed using the land surface parameters derived from Landsat 8 imagery and other environmental variables influencing soil salinity. This includes data pre-processing for feature selection using the XGBoost model. Separate soil salinity inversion models were developed using XGBoost, LightGBM, CatBoost, CNN and TabNet algorithms, and their performance was compared. The results indicate that TabNet achieved the best predictive performance among the five models, with \( R^2 = 0.57 \), \( MAE = 8.10 \), and \( RMSE = 11.53 \) on the test dataset. The results of the best performing model, TabNet, and the importance of individual features were subsequently analyzed using SHAP. The effect of some important factors such as groundwater table depth and altitude on salinization is clearly evident. Furthermore, the threshold of groundwater table depth for salinity control in Kashgar was also determined.

     This review traces the development of analytical chemistry as a major research contributor at Chiang Mai University (CMU) over its 60-year life. The evolution of analytical chemistry at CMU has been systematically traced using bibliometric analysis of the scientific literature over each of the six decades. The simplicity and creativity that are features of the research work were born of necessity, given the limitations on equipment and resources in the earlier decades. These underlying themes of simplicity and creativity have been perpetuated throughout the 60-year period despite increasingly sophisticated research, through the use of simple materials for fabrication, natural reagents, common information technology (IT) devices for detection, with an emphasis on green chemistry and sustainable approaches.

    This study investigates the spatial and seasonal distribution of potentially harmful dinoflagellates (PHDs) and their environmental drivers in the coastal waters of Songkhla Province, Thailand. Sampling was conducted across five stations: two semi-enclosed coastal areas (Site A: A1 and A2) and three exposed coastal areas (Site B: B1, B2 and B3). The sampling period, from July 2023 to March 2024, covered the Southwest Monsoon (SWM), Northeast Monsoon (NEM), and Intermediate Dry (IMD) seasons. Twelve PHD species were identified. Seven species (Noctiluca scintillans, Dinophysis caudata, D. miles, Tripos furca, T. fusus, T. tripos, and T. trichoceros) were detected consistently across all sites. Noctiluca scintillans and T. furca were the most abundant and widespread across all sites and seasons. ANOVA revealed significant seasonal effects on the abundance of D. caudata, D. miles, and T. macroceros, while T. fusus showed significant spatial variation (p < 0.05). Canonical Correspondence Analysis (CCA) indicated that dissolved oxygen (DO), pH, temperature, and nitrite concentrations were key variables influencing PHD distribution. Diversity was higher at Site B (H′ = 1.45, E = 0.61, S = 11) than at Site A (H′ = 1.30, E = 0.54, S = 11). Low DO and high nutrient levels in semi-enclosed areas were associated with freshwater inflows and aquaculture activity, whereas exposed coastal stations showed greater physicochemical stability but remained sensitive to nutrient enrichment during the NEM and IMD seasons. Integrated statistical analyses underscored the role of both monsoonal hydrodynamics and anthropogenic nutrient loading in regulating harmful dinoflagellate assemblages along the Songkhla coast. The findings emphasize the importance of site-specific, seasonally adaptive monitoring to the management of coastal water quality and mitigation of harmful algal blooms. The insights provided into the ecological dynamics of tropical coastal systems can inform future strategies for sustainable coastal zone management and support the aims of Sustainable Development Goal (SDG) 14: Life Below Water.

     Bambusicolous fungi comprise a diverse assemblage of species that inhabit a wide range of bamboo species. During an ongoing investigation of bambusicolous fungi in Guangdong Province, China, two interesting strains were isolated from decaying culms of Phyllostachys edulis and Bambusa sinospinosa. Based on morphological characteristics and phylogenetic analysis, the two collections are identified as the sexual and asexual states of a new species, Roussoella yangjiangensis. Roussoella yangjiangensis is characterized by bi-loculate ascostromata, cylindrical asci, fusiform, yellowish brown to dark brown, 1-septate, longitudinally striated ascospores with a sheath, and an asexual morph producing pseudostromatic pycnidia, monophialidic conidiogenous cells, and cylindrical to oblong, brown, aseptate conidia. Phylogenetic analysis of combined LSU, ITS, tef1-α, and rpb2 sequence data reveals that R. yangjiangensis is closely related to R. aseptata and R. yunnanensis, but forms a separate branch. A morphological comparison among these phylogenetically related taxa and other morphologically similar species further support the establishment of the novel species. In this study, the polyphyletic nature of Roussoella is also revealed, and the classification of R. arundinacea, R. chinensis and R. mexicana is discussed.

     The recently discovered ene reductase from the cyanobacterium Chroococcidiopsis thermalis (CtOYE)—a member of the old yellow enzyme (OYE) family—exhibits high activity and enantioselectivity toward activated alkenes, but its activity toward alkynes remains unexplored. Using 3-phenylpropiolonitrile as a model substrate, we demonstrated that CtOYE catalyzed the partial reduction of the alkyne 3-phenylpropiolonitrile to yield exclusively (Z)-cinnamonitrile, with no over-reduction to the saturated alkane. Molecular docking revealed a unique substrate binding mode where a tyrosine residue (Y351), rather than the canonical proton donor Y183, was positioned to protonate the α-carbon, rationalizing the observed (Z)-selectivity. Molecular dynamics (MD) simulations suggested higher flexibility of the enzyme-alkyne complex compared to the enzyme-alkene product complex, which might contribute to catalytic performance. Through systematic optimization of reaction conditions (pH, temperature, and concentrations of glucose, NADP⁺, glucose dehydrogenase, and enzyme), we achieved a significant increase in conversion. Our findings highlighted the potential of CtOYE as a versatile biocatalyst for the challenging selective reduction of alkynes to valuable (Z)-alkenes, providing a sustainable alternative to metal-based catalysts.

     To elucidate the molecular mechanisms underlying waterlogging tolerance in alpine wetland plants, we conducted a comprehensive transcriptome analysis of Hippuris vulgaris L. subjected to waterlogging stress. Using Illumina HiSeq sequencing, we compared gene expression profiles between waterlogged (MW) and control (CK) root samples, generating 42.93 Gb of clean data from six biological replicates. A relatively small set of 123 differentially expressed genes (DEGs) was identified, consisting of 27 up-regulated and 96 down-regulated transcripts. This limited transcriptional response may reflect the inherent pre-adaptation of this alpine species to hypoxic conditions. Functional characterization revealed that these DEGs were primarily enriched in metabolic processes, catalytic activities (GO), secondary metabolite biosynthesis, plant hormone signaling, and protein homeostasis pathways (KEGG, EggNOG). Key up-regulated genes included those encoding pyruvate decarboxylase and alcohol dehydrogenase, which are crucial for anaerobic energy production. These findings provide valuable insights into the unique adaptive strategies of alpine wetland plants to waterlogging stress at the transcriptional level.

     The P-series of dyes have been designed and theoretically characterized through DFT and TD-DFT to systematically explore the underlying physical origin of the bridged TPA donor unit and to investigate its influence on DSSCs. Key parameters associated with the solar cell performance were characterized and analyzed in detail. The results indicate that the methylene-bridged TPA group not only enhances the planarity of the donor group while effectively lowering λ_total and EBE, thereby elevating the Jsc, but also promotes Voc due to differences of μ_normal. Furthermore, the design strategy of the bridged TPA group has been explored preliminarily. A TPA donor group bridged by an N atom or group is favorable for both Jsc and Voc. Lastly, the newly designed dye P12 combines the virtues of both C-bridged and N-bridged groups, demonstrating outstanding Jsc and Voc among all P-series dyes. This finding further validates the correctness of previous conclusions, and P12 emerges as the best alternative dye molecule in this work.

     The plant-mediated synthesis of zinc oxide nanoparticles (ZnO NPs) using Morus alba L. leaf extract has been developed as a low-cost, environmentally benign, and simple approach. Characterization techniques such as UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to confirm biosynthesis, crystalline nature, morphology, dimensions, and elemental composition of the ZnO NPs. XRD confirmed the hexagonal wurtzite phase of ZnO with an average crystallite size of 30.54 nm. X-ray dispersive spectroscopy suggests that the composition of ZnO NPs is represented by the emission of 76% of the total energy by zinc and 13% by oxygen. The antibacterial activity of the biosynthesized ZnO NPs was evaluated, which indicates significant inhibition of bacterial strains, including Vibrio cholera and Escherichia coli (O157:H7), as compared to native ZnO. The maximum inhibition zones of ZnO NPs at a 50 mg/mL concentration were observed for V. cholerae and E. coli (O157:H7) at 24.3 ± 2.4 and 16.5 ± 2.7 mm, respectively. Moreover, the photocatalytic activity of the synthesized ZnO NPs was examined through the photodegradation of a methylene blue (MB) solution under solar light irradiation. The photodegradation efficiency of MB increased by 50% at ZnO NP concentrations of 30 ppm. This suggests that the synthesized ZnO NPs exhibited promising photocatalytic and biological properties in various applications.

     The steel industry generates large quantities of waste, including mill scale and hot-rolled steel sludge. These by-products pose serious environmental and economic challenges. This study proposes a sustainable strategy to convert them into LaFeO_3±δ-based perovskite materials for gas sensing applications. Iron oxide precursors were recovered, purified, and processed via mechanochemical milling followed by calcination at 1200 °C to produce LaFeO3±δ powders. Among all synthesized materials, the hot-rolled steel waste-derived material (LFO-HRSW) exhibited the best performance. SEM analysis revealed the smallest grain size (0.31 µm) and pore diameter (0.36 µm), which enhanced surface area and gas interaction. When exposed to combustion gases at 200 °C, its electrical resistivity increased from 19.56 Ω·m in air to 32.02 Ω·m, yielding a high sensor signal of 1.64. LFO-HRSW also responded the fastest, stabilizing within 2 min of gas exposure. These results highlight its superior sensitivity and real-time detection capability. This work is the first to directly transform mill scale and hot-rolled steel wastes into LaFeO3±δ perovskites for gas sensing applications. It offers a low-cost route to high-performance sensors, supports a circular economy approach for steel waste utilization, and provides potential benefits for environmental monitoring and industrial emission control.

     The permanganate index is a comprehensive indicator used to evaluate water quality, as it indicates the pollution level of organic and inorganic oxidizable substances in water. In this study, the permanganate index was chosen because it effectively reflects the pollutants released from both sediment resuspension and algal growth, providing a more holistic water quality assessment than parameters targeting individual pollutants. Since sediment and algae are potential causes for the increase in I_mn, it is imperative to explore their individual and combined effects. In this study, we artificially added sediment to water to simulate eutrophic water for algae growth. The sediment and surface water were obtained from the end of an artificial channels. We cultured algae for 41 days and observed the changes in I_mn, algal density, nitrogen, and phosphorus. The results showed that organic matter in sediment and algal growth increased in I_mn in the water. The sediment resuspension released organic matter into the water, resulting in a significant increase in I_mn. On the first day of the experiment, the addition of 1.6% sediment in the water sample led to an increase in I_mn of 14.7 mg/L. The dissolved phosphate in sediment also stimulated the growth of algae resulting in release of reducing metabolites and further increase in I_mn. The I_mn of the 1.6% sediment treatment group increased to 30.1 mg/L by day 41 of culture. Correlation analysis showed that I_mn was positively correlated with algal density, whereas total phosphorus content was significantly negatively correlated with algal density.

     The gilled macrofungus Omphalotus flagelliformis, a member of the family Omphalotaceae, has not previously been confirmed to exhibit bioluminescence. Although previous references have suggested possible light emission, no verifiable photographic or field documentation has been available until now. In this study, we present the first confirmed observation and photographic evidence of bioluminescence in O. flagelliformis, collected from a subtropical region in Yunnan Province, China. Bioluminescence was consistently observed in mature basidiomata and mycelium of living cultures under dark conditions, primarily emanating from the gills. Morphological and phylogenetic analyses based on the internal transcribed spacer (ITS) region confirmed the species identity as O. flagelliformis. The outcomes of this study provide significant insights into the known distribution of bioluminescent capacity within the genus Omphalotus and contribute to the understanding of the evolution of this trait in Basidiomycota.

     This study advances seismic forecasting and probabilistic hazard analysis in tectonically active regions by systematically evaluating how alternative model assumptions influence risk estimates. Taiwan, as a tectonically complex region, serves as the basis for comparing Poisson-based and McGuire-style probabilistic seismic hazard assessment (PSHA) models through comprehensive simulations and in-depth evaluation of six major urban centers. The McGuire-style model, which integrates active fault geometry, recurrence intervals, and magnitude–distance distributions, consistently predicts higher peak ground acceleration (PGA) values, especially in eastern and southern Taiwan, where seismic hazard is high but often underestimated by time-independent approaches. In contrast, the Poisson model, grounded in historical catalogs, tends to smooth hazard estimates and overlook localized risk. Deaggregation analyses demonstrate that the McGuire model more accurately captures the dominant near-field sources, thereby enhancing site-specific hazard attribution. To reconcile these divergences, we propose a hybrid PSHA framework that combines empirical coverage with fault-based specificity, enabling spatially explicit and source-sensitive hazard forecasting. This dual-model approach improves predictive accuracy and supports resilience-oriented seismic planning. The findings provide a robust scientific foundation for earthquake risk governance in complex tectonic settings and contribute to global efforts in disaster risk reduction, aligning with the Sendai Framework.

     The occurrence and seasonal development of three Cephaleuros species, namely C. karstenii, C. pilosa, and C. virescens, were assessed on Lansium domesticum, Garcinia mangostana, and Mangifera indica hosts, respectively, at study sites at Prince of Songkla University, southern Thailand. We compared the development of algal thalli, the number of thalli (lesions), and reproductive structures (gametangia and sporangia) between the rainy and summer seasons. Fresh algal thalli appeared on the leaves of the three plant hosts during the rainy season. The development of gametangia and sporangia on algal thalli varied between different Cephaleuros species. However, the release of gametes and zoospores occurred during the rainy season. The average numbers of thalli, gametangia, and sporangia of the three Cephaleuros species during the rainy season were significantly higher than during the summer. Pearson correlation analysis indicates that the occurrence of plant-parasitic algae is influenced by environmental factors such as humidity and rainfall patterns, with higher infection rates observed during the rainy season. Based on the results of this study, the number of algal thalli increased, and the maturation and release of gametes and zoospores predominantly occurred in the rainy season in tropical Thailand. This study highlights the need for increased awareness of plant-parasitic algae as a potential threat to crop production in southern Thailand. Further development of integrated management practices tailored to local climatic conditions should be explored.