Seed morphological traits and genotypic diversity of weedy rice (Oryza sativa f. spontanea) populations found in the Thai Hom Mali rice fields of north-eastern Thailand

Preecha Prathepha 한국잡초학회 2009 Weed Biology and Management Vol.9 No.1

Investigation and Mitigation of Overvoltage Due to Ferroresonance in the Distribution Network

Preecha Sakarung,Teratam Bunyagul,Somchai Chatratana 대한전기학회 2007 Journal of Electrical Engineering & Technology Vol.2 No.3

This paper reports an investigation of overvoltages caused by ferroresonance in the distribution system, which consists of a bank of open-delta single-phase voltage transformers. The high voltage sides of the voltage transformer are connected to the distribution system via three single-phase fuse cutouts. Due to the saturation characteristic of the transformer cores, ferroresonance can occur in the condition that the transformer is energized or deenergized with single-phase switching operation of the fuse cutouts. The simulation tool based on EMTP is used to investigate the overvoltages at the high side of voltage transformer. Bifurcation diagrams are used to present the ferroresonance behavior in ranges of different operating conditions. The simulation results are in good agreement with the results from the experiment of 22 ㎸ voltage transformers. The mitigation technique with additional damping resistors in the secondary windings of the voltage transformers will be introduced. Brief discussion will be made on the physical phenomena related to the overvoltage and the damage of voltage transformer.

Computer Network Security Based On Support Vector Machine Approach

Preecha Somwang,Woraphon Lilakiatsakun 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10

At present, incidents of computer networks attack are significantly increasing therefore the effective Intrusion Detection Systems (IDS) are essential for information systems security. In order for the IDS to be effective, they have the capability of detecting new arrival attacks. Additionally, the correct detection rate should also be at high level whereas the low false positive detection rate is preferred. This paper proposes the new intrusion detection technique by using hybrid methods of unsupervised/supervised learning scheme. The proposed technique integrates the Principal Component Analysis (PCA) with the Support Vector Machine (SVM). The PCA is applied to reduce high dimensional data vectors and distance between vectors including its projection onto the subspace. SVM is then used to classify different groups of data, Normal and Anomalous. The results show that the proposed technique can improve the performance of anomaly intrusion detection, the intrusion detection rate and generate fewer false alarms.

Designing Wireless Sensor Network for Detecting Chainsaw Noise in a Forested Watershed

Preecha Kocharoen Sarinya Nuan,Petch Nantivatana 대한전자공학회 2015 ITC-CSCC :International Technical Conference on Ci Vol.2015 No.6

The wireless sensor network for chainsaw noise detection in a forested watershed is proposed. This proposed technique uses simple acoustic microphone as a sensor which is simple and low complexity. Only signal in the medium-frequency and high-frequency band is analyzed. In order to increase reliability of the chainsaw noise detecting decision, the multiple sensor nodes around the noise source will do processing at the central processing node or coordinator node. The hardware platform of this wireless sensor network used the existing deployed wireless sensor network for flashflood warning was installed at Nampung-forested Watershed, Loei province, Thailand.

Investigation and Mitigation of Overvoltage Due to Ferroresonance in the Distribution Network

Sakarung, Preecha,Bunyagul, Teratam,Chatratana, Somchai The Korean Institute of Electrical Engineers 2007 Journal of Electrical Engineering & Technology Vol.2 No.3

This paper reports an investigation of overvoltages caused by ferroresonance in the distribution system, which consists of a bank of open-delta single-phase voltage transformers. The high voltage sides of the voltage transformer are connected to the distribution system via three single-phase fuse cutouts. Due to the saturation characteristic of the transformer cores, ferroresonance can occur in the condition that the transformer is energized or deenergized with single-phase switching operation of the fuse cutouts. The simulation tool based on EMTP is used to investigate the overvoltages at the high side of voltage transformer. Bifurcation diagrams are used to present the ferroresonance behavior in ranges of different operating conditions. The simulation results are in good agreement with the results from the experiment of 22 kV voltage transformers. The mitigation technique with additional damping resistors in the secondary windings of the voltage transformers will be introduced. Brief discussion will be made on the physical phenomena related to the overvoltage and the damage of voltage transformer.

Using the life course approach to explain the onset and continuity of preventive health-care behaviors: A comparative study across four countries

Anil Mathur,Preecha Yingwattanakul,이의훈,Cristiane Pizzutt 한국마케팅과학회 2020 마케팅과학연구 Vol.30 No.1

The objective of this research is to examine the factors that promote the onset and continuity of preventive health-care behaviors over the course of one’s life. Using the life course paradigm as an overarching conceptual framework, hypotheses are developed that relate to the role of life events that trigger processes responsible for the initiation and discontinuation of three preventive health-care behaviors: exercising, using dietary supplements or vitamins, and having regular physical exams. The samples used are drawn from the United States, Thailand, South Korea, and Brazil. Results suggest that experience of life events and consequential life-course adaptation processes (socialization, stress and coping, and human development) are important predictors of initiation and discontinuation of preventive health-care behaviors. The relative influence of these explanatory variables varies across cultures, suggesting the importance of contextual factors in explaining preventive health-care behaviors. Implications for further research are also suggested.

Propolis from the Stingless Bee Trigona incisa from East Kalimantan, Indonesia, Induces In Vitro Cytotoxicity and Apoptosis in Cancer Cell lines

Kustiawan, Paula M,Phuwapraisirisan, Preecha,Puthong, Songchan,Palaga, Tanapat,Arung, Enos T,Chanchao, Chanpen Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Background: Previously, stingless bee (Trigona spp.) products from East Kalimantan, Indonesia, were successfully screened for in vitro antiproliferative activity against human cancer derived cell lines. It was established that propolis from T. incisa presented the highest in vitro cytotoxicity against the SW620 colon cancer cell line (6% cell survival in $20{\mu}g/mL$). Materials and Methods: Propolis from T. incisa was extracted with methanol and further partitioned with n-hexane, ethyl acetate and methanol. The in vitro cytotoxicity of the extracts was assessed by the MTT assay against human colon (SW620), liver (Hep-G2), gastric (KATO-III), lung (Chago) and breast (BT474) cancer derived cell lines. The active fractions were further enriched by silica gel quick column, absorption and size exclusion chromatography. The purity of each fraction was checked by thin layer chromatography. Cytotoxicity in BT-474 cells induced by cardanol compared to doxorubicin were evaluated by MTT assay, induction of cell cycle arrest and cell death by flow cytometric analysis of propidium iodide and annexin-V stained cells. Results: A cardol isomer was found to be the major compound in one active fraction (F45) of T. incisa propolis, with a cytotoxicity against the SW620 ($IC_{50}$ of $4.51{\pm}0.76{\mu}g/mL$), KATO-III (IC50 of $6.06{\pm}0.39{\mu}g/mL$), Hep-G2 ($IC_{50}$ of $0.71{\pm}0.22{\mu}g/mL$), Chago I ($IC_{50}$ of $0.81{\pm}0.18{\mu}g/mL$) and BT474 (IC50 of $4.28{\pm}0.14{\mu}g/mL$) cell lines. Early apoptosis (programmed cell death) of SW620 cells was induced by the cardol containing F45 fraction at the $IC_{50}$ and $IC_{80}$ concentrations, respectively, within 2-6 h of incubation. In addition, the F45 fraction induced cell cycle arrest at the G1 subphase. Conclusions: Indonesian stingless bee (T. incisa) propolis had moderately potent in vitro anticancer activity on human cancer derived cell lines. Cardol or 5-pentadecyl resorcinol was identified as a major active compound and induced apoptosis in SW620 cells in an early period (${\leq}6h$) and cell cycle arrest at the G1 subphase. Thus, cardol is a potential candidate for cancer chemotherapy.

Inhibitory Efficacy of Cycloartenyl Ferulate against a-Glucosidase and a-Amylase and Its Increased Concentration in Gamma-Irradiated Rice (Germinated Rice)

Sompong Sansenya,Apirak Payaka,Preecha Mansalai 한국식품영양과학회 2023 Preventive Nutrition and Food Science Vol.28 No.2

Cycloartenyl ferulate is a derivative of g-oryzanol with varied biological activity, including diabetes mellitus treatment. This research focused on improving the cycloartenyl ferulate accumulation in germinated rice by gamma irradiation under saline conditions. Moreover, the inhibitory potential of cycloartenyl ferulate against carbohydrate hydrolysis enzymes (a-glucosidase and a-amylase) was investigated through in vitro and in silico techniques. The results revealed that cycloartenyl ferulate increased in germinated rice under saline conditions upon gamma irradiation. A suitable condition for stimulating the highest cycloartenyl ferulate concentration (852.20±20.59 mg/g) in germinated rice was obtained from the gamma dose at 100 Gy and under 40 mM salt concentration. The inhibitory potential of cycloartenyl ferulate against a-glucosidase (31.31±1.43%) was higher than against a-amylase (12.72±1.11%). The inhibition mode of cycloartenyl ferulate against a-glucosidase was demonstrated as a mixed-type inhibition. A fluorescence study confirmed that the cycloartenyl ferulate interacted with the a-glucosidase’s active site. A docking study revealed that cycloartenyl ferulate bound to seven amino acids of a-glucosidase with a binding energy of −8.8 kcal/mol and a higher binding potential than a-amylase (−8.2 kcal/mol). The results suggested that the gamma irradiation technique under saline conditions is suitable for stimulating g-oryzanol, especially cycloartenyl ferulate. Furthermore, cycloartenyl ferulate demonstrated its potential as a candidate compound for blood glucose management in diabetes mellitus treatment.

Wireless Sensor Network for Flash-flood Warning : Nampung-forested Watershed

Termpong Srited,Kata Jaruwongrungsee,Preecha Kocharoen 대한전자공학회 2015 ITC-CSCC :International Technical Conference on Ci Vol.2015 No.6

In this paper, wireless sensor network for flash-flood warning is proposed. The prototype system was created which are the sensor nodes the router nodes and the central processing node. The rain gauge sensors and the water level sensors were used in this system for monitoring rain rate in the forested watershed and the water level at the weir. The system was tested in laboratory and after that it was installed at Nampung-forested watershed, Loei province, Thailand.

Synthesis of furofuran lignans as antidiabetic agents simultaneously achieved by inhibiting a-glucosidase and free radical

Wisuttaya Worawalai,Phonpimon Khongchai,Nantaporn Surachaitanawat,Preecha Phuwapraisirisan 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.10

Furofuran lignans such as sesamin have been recognized as promising antidiabetic agents as they possess curative as well as preventive effects toward diabetes complications. However, to date the structure–activity relationship has not been investigated due to the lack of a practical synthetic route capable of producing diverse furofuran lignans. Herein, we first introduced a single-step synthesis of these compounds starting from samin (4). Reaction of samin with a variety of electron-rich phenolics under acidic conditions afforded a total of 23 diverse furofuran lignans. On examination their inhibitions against a-glucosidase and free radicals, lignans having a free hydroxy group showed considerably enhanced inhibition, compared with their corresponding starter 4 and related lignans sesamin (1) and sesamolin (3). In addition, the mechanism underlying the a-glucosidase inhibition of a particular active lignan (epi-6) was verified to be mixed manner between competitive and noncompetitive inhibition.