Chiang Mai University
  • Chiang Mai, Thailand
Recent publications
Distribution of PM0.1 , PM1 and PM2.5 particle-and gas-polycyclic aromatic hydrocarbons (PAHs) during the 2019 normal, partial and strong haze periods at a background location in southern Thailand were investigated to understand the behaviors and carcinogenic risks. PM 1 was the predominant component, during partial and strong haze periods, accounting for 45.1% and 52.9% of total suspended particulate matter, respectively, while during normal period the contribution was only 34.0%. PM0.1 concentrations, during the strong haze period, were approximately 2 times higher than those during the normal period. Substantially increased levels of particle-PAHs for PM0.1 , PM1 and PM2.5 were observed during strong haze period, about 3, 5 and 6 times higher than those during normal period. Gas-PAH concentrations were 10 to 36 times higher than those of particle-PAHs for PM2.5. Average total Benzo[a]Pyrene Toxic Equivalency Quotients (BaP-TEQ) in PM0.1 , PM1 and PM2.5 during haze periods were about 2-6 times higher than in the normal period. The total accumulated Incre-mental Lifetime Cancer Risks (ILCRs) in PM0.1 , PM1 and PM2.5 for all the age-specific groups during the haze effected scenario were approximately 1.5 times higher than those in non-haze scenario, indicating a higher potential carcinogenic risk. These observations suggest PM0.1 , PM1 and PM2.5 were the significant sources of carcinogenic aerosols and were significantly affected by transboundary haze from peatland fires. This leads to an increase in the volume of smoke aerosol, exerting a significant impact on air quality in southern Thailand, as well as many other countries in lower southeast Asia.
Ancient historic buildings are constructed with antiquated construction techniques. Hence, they are vulnerable to an earthquake and require appropriate seismic strengthening. To complete the task, dynamic parameters are needed. This study proposes an inverse analysis to identify the dynamic properties of the structure. The proposed algorithm uses Newmark’s time stepping method with the Gauss-Newton scheme. An earthquake-induced vibration of a selected pagoda was recorded by pre-installed two accelerometers, which were used to perform the inverse analysis. The average acceleration and linear acceleration of Newmark’s scheme were adopted, and the obtained dynamic properties were compared. The results show that the dynamic structural parameters from the two methods are comparable. The values of natural frequency are in the range obtained from the previous study.
This paper investigates the properties of Voronoi diagrams in which the generators are on an Archimedean spiral curve with various divergence angles. We apply geometrical properties to construct algorithms to recognize whether the given Voronoi diagram is the Archimedean Voronoi diagram from linear parastichy patterns.
Sesamin, a significant lignin compound isolated from sesame (Sesamum indicum Linn), is well known for its antioxidant, anti-inflammatory, and tissue growth promotion properties. Bioabsorbable poly(ε-caprolactone) (PCL) is also a well-known polymer applied to various fields of medicine as biomaterials. The main objective of this research was to produce a prototype material from PCL and sesamin by electrospinning technique for bone tissue engineering applications. Dichloromethane and dimethylformamide (7:3) mixture was used as the solvent system for fabrication of PCL nanofiber with different loads of sesamin concentrations (1–6 wt%). The crystallinity levels decreasing and the entrapment efficiency increasing (86.87%–93.97%) were observed while sesamin concentrations were increased. The infrared spectra of electrospun mats confirmed that sesamin corporated into fibrous networks. The sesamin-loaded PCL nanofibrous membranes showed a significant release of sesamin in the range of 1.28–8.16 μg/mL within 10 weeks. The release data were fitted to zero order, first order, Higuchi and Korsmeyer-Peppas models to evaluate sesamin-releasing mechanisms and kinetics. The releasing kinetics of sesamin followed the Fickian diffusion mechanism of Korsmeyer-Peppas (R² = 0.99). In vitro experiments with an osteosarcoma cell line (MG-63) revealed cell attachment, biocompatibility, and promotion of bone marker expression, the alkaline phosphatase (ALP) activity were studied. The electrospun PCL nanofiber loaded with sesamin had the potential as a scaffold for sesamin delivery to bone cells and applications in biomedicine.
Carbon-based nanomaterials, such as carbon nanotubes, fullerenes, nanodiamonds, and graphene, have been investigated for various biomedical applications, including biological imaging, photothermal therapy, drug/gene delivery, cancer therapy, biosensors, and electrochemical sensors. Graphene oxide (GO) has unique physicochemical properties and can be used to restore conductivity through oxidation. In this study, we developed poly(N-isopropylacrylamide) (PNIPAM)-based nanogel systems containing GO for controlled in vitro drug delivery. The photothermal effects of the PNIPAM/GO- and PNIPAMAAM/GO-based nanogel systems were enhanced. The release of DOX from the PNIPAM/GO-based nanogel was achieved using the photothermal effect of near-infrared irradiation. Using a Cell Counting Kit-8 assay, the cytotoxicity of all conditions demonstrated that the PNIPAM composite-based nanogels were biocompatible with no significance.
Objective Lipopolysaccharide (LPS), a component of gram-negative bacteria, is a potent innate immune stimulus. The interaction of LPS with innate immune cells induces the production of proinflammatory cytokines and chemokines, thereby leading to the control of infection. In the present study, we investigated the effect of a wide range of LPS concentrations on the regulation of various proinflammatory cytokines and chemokines in human primary monocytes and T lymphocytes. Results We demonstrated that a very low concentration of LPS could regulate the production of cytokines and chemokines in monocytes but not T lymphocytes. Unexpectedly, very low concentrations of LPS (0.0025 and 0.005 ng/mL) could induce TNF-α and IL-6 production, respectively, in monocytes. Our findings provide evidence that in the presence of monocytes, even very low endotoxin contamination could induce cytokine production. We suggest that the recombinant proteins used to investigate immune functions must be thoroughly screened for endotoxins using a highly sensitive method.
We present a single-step, room-temperature synthesis of fluorescent organosilica nanobeads (FOS NBs). The FOS NBs were synthesized under aqueous conditions using (3-aminopropyl)triethoxysilane (APTES) as the silicon source in the presence of l -ascorbic acid (L-AA). In the APTES/L-AA/water ternary phase, the hydrolysis and condensation reaction of APTES occurred under acidic conditions to form spherical FOS NBs with an average diameter of 426.8 nm. FOS NBs exhibit excellent colloidal stability in aqueous media. The formation of FOS NBs was complete within a 10 min reaction time, which indicates potential for large-scale mass-production synthesis of luminescent colloidal NBs. The FOS NBs exhibited blue photoluminescence (PL) under UV excitation in the absence of an additional high temperature calcination process or with the incorporation of any fluorophores. This phenomenon is attributed to the presence of carbon-containing defects, which act as luminescent centers formed by the reaction between amino groups in the APTES and l -ascorbic acid reductant. Finally, the results of a cytotoxicity test and cellular uptake experiments revealed that the FOS NBs showed potential as optical contrast agents for bioimaging. Graphical Abstract
Background Caloric restriction and exercise are lifestyle interventions that effectively attenuate cardiometabolic impairment. However, cardioprotective effects of long-term lifestyle interventions and short-term lifestyle interventions followed by weight maintenance in prediabetes have never been compared. High cardiorespiratory fitness (CRF) has been shown to provide protection against prediabetes and cardiovascular diseases, however, the interactions between CRF, prediabetes, caloric restriction, and exercise on cardiometabolic health has never been investigated. Methods Seven-week-old male Wistar rats were fed with either a normal diet (ND; n = 6) or a high-fat diet (HFD; n = 30) to induce prediabetes for 12 weeks. Baseline CRF and cardiometabolic parameters were determined at this timepoint. The ND-fed rats were fed continuously with a ND for 16 more weeks. The HFD-fed rats were divided into 5 groups (n = 6/group) to receive one of the following: (1) a HFD without any intervention for 16 weeks, (2) 40% caloric restriction for 6 weeks followed by an ad libitum ND for 10 weeks, (3) 40% caloric restriction for 16 weeks, (4) a HFD plus an exercise training program for 6 weeks followed by a ND without exercise for 10 weeks, or (5) a HFD plus an exercise training program for 16 weeks. At the end of the interventions, CRF and cardiometabolic parameters were re-assessed. Then, all rats were euthanized and heart tissues were collected. Results Either short-term caloric restriction or exercise followed by weight maintenance ameliorated cardiometabolic impairment in prediabetes, as indicated by increased insulin sensitivity, improved blood lipid profile, improved mitochondrial function and oxidative phosphorylation, reduced oxidative stress and inflammation, and improved cardiac function. However, these benefits were not as effective as those of either long-term caloric restriction or exercise. Interestingly, high-level baseline CRF was correlated with favorable cardiac and metabolic profiles at follow-up in prediabetic rats, both with and without lifestyle interventions. Conclusions Short-term lifestyle modification followed by weight maintenance improves cardiometabolic health in prediabetes. High CRF exerted protection against cardiometabolic impairment in prediabetes, both with and without lifestyle modification. These findings suggest that targeting the enhancement of CRF may contribute to the more effective treatment of prediabetes-induced cardiometabolic impairment.
Background: Diabetes Self-Management Education (DSME) is a fundamental aspect of diabetes care, but no standard program exists in Thailand. Understanding current patterns of illness perceptions (concerns) and self-management practices among patients with diabetes in Thailand is vital to develop culturally tailored DSME programs. This study sought to explore the association between reported self-management practices and diabetes perceptions on glycemic control among patients with type 2 diabetes in Chiang Mai Province, Thailand. Specifically, the study examined whether the association between illness perceptions and diabetes control was mediated by self-management. Methods: This was a cross-sectional study conducted among type 2 diabetes patients on outpatient care and follow-up in four districts hospitals in Chiang Mai, Thailand. Illness perceptions was measured by the Brief Illness Perceptions Questionnaire (BIPQ). Self-management practices were measured by Summary Diabetes Self-Care activities (SDSCA). For illness perceptions and self-management practices, patients were classified into two groups, high level and low level based on the median values. Univariate and multivariable analyses were done to determine the association between the determinant factors: self-care practices and illness perceptions and the outcome of interest- good glycemic control (HbA1c < 7%). Results: Of the 200 participants recruited into the study, 180 completed the questionnaire. Only 35% of participants had good glycemic control (HBA1c < 7.0). Both illness perceptions and self-management practices were independently linked to glycemic control. Among illness perceptions, a sense of personal control was strongly associated with good glycemic control (p = 0.01). For self-management, appropriate diet (p = 0.03) and medication adherence (p = 0.05) were associated with good glycemic control. After adjustments for key baseline characteristics, patients with high levels of illness perceptions were less likely to achieve glycemic control (OR 0.55, 95% CI 0.29 to 1.14, p = 0.11) and those with high level of self-management were more likely to achieve glycemic control (OR 2.11, 95% CI 1.04 to 4.30, p = 0.04). The effect size for illness perception attenuated when further adjusted for levels of self-management (OR 0.88, 95% CI 0.39 to 1.96, p = 0.75) while the effect size for self-management and glycemic control did not materially change (OR 2.30, 95% CI 1.06 to 5.02, p = 0.04). Conclusion: Illness perceptions and self-management practices are associated with glycemic control. Future culturally tailored interventions in Thailand aimed at improving glycemic should focus on personal control, improving diet and treatment adherence as these are more likely to help improve diabetes control as demonstrated in this study.
Background The impact of the coronavirus disease 2019 (COVID-19) outbreak on out-of-hospital cardiac arrest (OHCA) has been of interest worldwide. However, evidence from low-resource emergency medical service systems is limited. This study investigated the effects of the COVID-19 outbreak on the prehospital management and outcomes of OHCA in Thailand. Methods This multicentered, retrospective, observational study compared the management and outcomes of OHCA for 2 periods: pre-COVID-19 (January–September 2019) and during the outbreak (January–September 2020). Study data were obtained from the Thai OHCA Network Registry. The primary outcome was survival rate to hospital discharge. Data of other OHCA outcomes and prehospital care during the two periods were also compared. Results The study enrolled 691 patients: 341 (49.3%) in the pre-COVID-19 period and 350 (50.7%) in the COVID-19 period. There was a significant decrease in the survival rate to discharge during the COVID-19 outbreak (7.7% vs 2.2%; adjusted odds ratio [aOR], 0.34; 95% confidence interval [CI], 0.15–0.95). However, there were no significant differences between the 2 groups in terms of their rates of sustained return of spontaneous circulation (33.0% vs 31.3%; aOR, 1.01; 95% CI, 0.68–1.49) or their survival to intensive care unit/ward admission (27.8% vs 19.8%; aOR, 0.78; 95% CI, 0.49–1.15). The first-responder response interval was significantly longer during the COVID-19 outbreak (median [interquartile range] 5.3 [3.2–9.3] min vs 10 [6–14] min; P < 0.001). There were also significant decreases in prehospital intubation (66.7% vs 48.2%; P < 0.001) and prehospital drug administration (79.5% vs 70.6%; P = 0.024) during the COVID-19 outbreak. Conclusion There was a significant decrease in the rate of survival to hospital discharge of patients with OHCA during the COVID-19 outbreak in Thailand. Maintaining the first responder response quality and encouraging prehospital advanced airway insertion might improve the survival rate during the COVID-19 outbreak.
In this paper, we examine various characteristics of both base and peak electricity spot prices and their returns, and investigate dependence structures, extreme co-movements, risk spillovers, and integration relationships among the five major European electricity markets, including France, Germany, the Netherlands, Spain, and the UK. To do so, we propose a new perspective by applying a hybrid of ARMA-GARCH, static and dynamic copulas, and dynamic state-space models with the Kalman filter to address the issue. Based on the results of the ARMA-GJR-GARCH model, we first find that there are spillover effects in the returns of both base and peak spot prices in the five European electricity markets, and there are heteroskedastic, asymmetric, and leverage effects with negative and positive shocks, including spikes and drops during both base and peak load periods. Hence, a decrease in prices will boom the variance of the returns, and a decrease in returns can lead to a much greater increase in volatility. Second, there exist some extents of positive dependencies, tail dependencies, and extreme co-movements among the European electricity markets based on the copula models. In addition, we find that the degree of (tail) dependence and the potential state of market integration are stronger and higher during the peak period than the base period, implying that the European electricity markets could boom or crash together, especially during the peak load period. Further, the results of both the dynamic copulas and dynamic state-space models show that most pairs of the European electricity markets co-move symmetrically and have a time-varying dependence, but do not appear to grow over time. Finally, we provide an application of the copula-GARCH model in estimating and predicting risk spillovers across the five European electricity markets. We document that there are high-risk spillover effects in the European electricity markets because the values of the Conditional Value-at-Risk (CoVaR) are large. Also, we find that the more integrated the market, the more the systematic risk contribution of the market as indicated by ΔCoVaR. Our findings provide useful information regarding the dependence, integration, risk management, and asset pricing for the European electricity markets.
Corrosion of aluminium anode in alkaline solution is a challenging matter for the development of a long-life aluminium anode in Al–air battery. This research focuses on grain size reduction by equal channel angular pressing (ECAP) of Al, Al–Zn, and Al–Zn–In samples. The average grain size of all samples after ECAP is lower than 1μm. Open circuit potential, potentiodynamic polarisation, electrochemical impedance spectroscopy, and self-corrosion test were carried out to study the effects of alloying elements (Zn, In) and grain size reduction by ECAP on the electrochemical behaviours of aluminium alloy anodes. The results show that alloying element, zinc, can improve the stability of ion dissolution by porous Al2ZnO4 film formation. Indium can activate ion dissolution that causes enhanced electrochemical activities for Al–Zn–In sample. Moreover, increasing grain boundaries through grain size reduction can enhance more negative potential and cause a uniformly corroded surface of Al–Zn–In sample, leading to a longer anode life in alkaline solution.
Commercial freezers are commonly used the outer wall as a heatsink. This heatsink needs surrounded ambient air for cooling, which is the natural convection mechanism. However, in theory the force convection provides more heat transfer than the natural convection. Therefore, energy consumption of the force convection is generally less than the natural convection. This study aims at testing and comparing the heat transfer between the natural convection and force convection of the heatsink of the commercial freezer. Moreover, this study investigated the potential of energy reduction of the freezer by using the natural convection and the force convection of the heatsink. In this study, the unmodified commercial freezer installed with the wind tunnel over the heatsink of the freezer was made. The necessary parameters such as heatsink surface temperature, cooling air temperature, ambient air temperature, velocity of cooling air, and power consumption of the freezer were collected. The testing conditions were varied the internal heat load of the freezer by using water as 0, 3, and 6 kg, and varied the cooling air velocity as 0, 1, 2, and 3 m/s. The results showed that the convection mechanism was significantly affected by energy consumption. Furthermore, it was clearly found that the heat transfer for the force convection was higher than the natural convection. Moreover, the use of force convection resulted in a lower energy consumption. In particular at the internal heat load of 6 kg, the energy consumption of the force convection decreased by 17.5%, 17.7%, and 20.5% as compared to the natural convection at the cooling air velocity of 1, 2, and 3 m/s, respectively. Based on the results obtained it can be concluded that the force convection for the freezer heatsink can be used to reduce energy consumption, which could be efficiently applied in the future works.
The transport sector accounts for massive global CO2 emissions. To achieve low-carbon transport systems, promoting electric vehicles (EVs) is a crucial strategy of worldwide countries. Since the current rapid growth of EVs, the total cost of ownership (TCO) of EVs has been studied among countries promoting EVs in their transport sector. This study presents TCO models of EVs compared to a conventional internal combustion engine (ICE) vehicle. The EVs considered in this study include a hybrid electric vehicle (HEV), a plug-in hybrid vehicle (PHEV), and a battery electric vehicle (BEV). The cost models consist of capital and operating costs, i.e., depreciation, maintenance, tax, insurance, loan interest, battery, and energy consumption costs. All data are obtained from real-world testing in Thailand. The TCO models are analyzed based on the average distance traveled, 20,000 km/year for over 15 years driving in urban areas. The results show that the TCO of ICE, HEV, PHEV, and BEV is 61.19, 54.94, 55.94, and 60.89 (1,000 USD), respectively. The lifetime TCO ratio for each holding year is also proposed. The HEV and PHEV seem to be suitable choices without any BEV support policies in Thailand. Additionally, using the TCO models and presenting as a 15-year lifetime TCO ratio, two case scenarios of different EV support policies are assumed, i.e., a government subsidy, or a retailer discount and battery price discount. Direct support towards the vehicles’ purchasing prices significantly decreases the TCO. The knowledge from this study could be helpful for consumers, manufacturer product planners, and government policymakers.
Electric vehicles (EVs) are broadly admired as an encouraging solution to decarbonize and relieve air pollution in metropolitan transportation. However, each powertrain gives different benefits depending on the actual usage context. This study investigates the energy consumption of various EVs compared to a conventional internal combustion engine (ICE) vehicle. The considered EVs include a hybrid electric vehicle (HEV), plug-in hybrid vehicle (PHEV), and battery electric vehicle (BEV). Different road characteristics in the biggest city of northern Thailand are tested as driving route modes, i.e., city, rural, and hill modes, to study the energy consumption of the powertrains under real-world driving scenarios. Additionally, the efficiency of the CO2 emission reduction of each powertrain, analyzed from the energy consumption, is presented through the Well-to-Wheel (WtW) basis. The results show that the BEV performs well with all route characteristics, while both hybrids are appropriate in different driving scenarios. On average, of all the route modes, the WtW CO2 emission of the HEV, PHEV, and BEV is about 65%, 50%, and 35%, respectively, compared to the ICE. The BEV only has WtT CO2 emission from its electricity source. Therefore, it can yield low emissions if renewable energy, such as solar or wind energy, is used as its electricity source instead of fossil fuels.
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Anak Iamaroon
  • Department of Oral Biology
Patcharawan Srisilapanan
  • Center of Excellence in Dental Public Health
Suchart Kothan
  • Department of Radiologic Technology
Kontad S Ounnunkad
  • Department of Chemistry
Jaroon Jakmunee
  • Faculty of Science
Information
Address
239 Huaykaew Rd, Suthep, Mueang Chiang Mai District,, Chiang Mai 50200, Chiang Mai, Thailand
Head of institution
Associate Professor Niwes Nantachit, M.D
Website
https://www.cmu.ac.th/
Phone
+66 5394 3661 to 5
Fax
+66 5394 2670