ISSN: 0125-2364, Online ISSN: 2586-9531

Volume 47 No.1 January-March 2019


P.000-1

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หน้าปก

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P.000-2

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บรรณาธิการแถลง

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P.000-3

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สารบัญ

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P.001-014

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Protein Phosphorylation in Human Health and Diseases

กระบวนการเติมหมู่ฟอสเฟตแก่โปรตีนและโรคที่เกี่ยวข้อง

พงศกร ถาวรพันธ์ สุภิญญา ธนาพงษ์ภิชาติ และ หาญศึก บุญเชิด*

Protein phosphorylation-dephosphorylation is the common post-translational modifications that regulate the structures and functions of cellular proteins involved in diverse biological processes ranging from control of cellular fate to regulation of metabolism. Owing to its significant roles, the cell needs to tightly modulate the phosphorylation-dephosphorylation to sustain cellular integrity. Disruption or dysregulation of the phosphorylation-dephosphorylation could lead to diseases such as diabetes mellitus, Parkinsonism, Alzheimer’s disease and cancer. The review in this issue focuses on the significant role of protein phosphorylation-dephosphorylation and signaling mechanisms involved in the processes. This issue also provides the information of phosphorylation-related diseases, highlighting the application of phosphorylation in development of targeted therapy.


P.015-025

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Comparison of Bacterial Population Structure in High and Low Somatic Cell Bovine Milk in Patthalung Province

การเปรียบเทียบโครงสร้างประชากรแบคทีเรียในตัวอย่างน้ำนมโค กลุ่มเซลล์โซมาติกสูงและต่ำในจังหวัดพัทลุง

ศุภชัย นิติพันธ์* นุกูล อินทระสังขา และ จิตรพล ประดิษฐ์ธรรม

This study is aimed to compare the bacterial population structure of two different raw milk sample groups, low somatic cell (LSC) and high somatic cell (HSC) samples, using culture-dependent and culture-independent methods. The somatic cell count was estimated by California Mastitis Test (CMT) and Fossomatic 5000. Based on difference of V3 sequences of 16S rRNA gene using Denaturing Gradient Gel Electrophoresis (DGGE), bacterial diversity was identified. The bovine raw milk samples were collected from dairy farm of Thaksin University, Pha-prayom district, Patthalung province. The total bacterial counts in both samples were grown on Plate Count Agar (PCA) that showed no significant difference (p≤0.05) between HSC and LSC which were 4.75±0.9, 4.29±0.87 and 3.81±1.32 Log CFU/ml of CMT0, CMT+2 and CMT+3, respectively. There are four bacterial phyla from culture-dependent methods including Firmicutes Proteobacteria Actinobacteria and Bacteroidetes. This method showed that the genera of Staphylococcus and Bacillus were dominant bacteria and Corynebacterium spp. were frequency detected from HSC samples higher than LSC samples. Moreover, Sphingobacterium spp. were presented in HSC but not in LSC. While culture-dependent methods showed three phyla including Firmicutes Proteobacteria Actinobacteria as well as uncultured bacteria. Streptococcus spp. Lactobacillus spp. and Bacillus spp. were detected as dominant bacteria.


P.026-033

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Purification of cyanobacterial toxin, microcystins, by DEAE and Strata-X SPE chromatography

การทำบริสุทธิ์สารพิษจากไซยาโนแบคทีเรีย ไมโครซิสตินโดยดีอีเออี และสตราต้า-เอ๊กซ์ โครมาโตกราฟี

Kranokpron Moolwangand and Theerasak Somdee*

The lyophilized cells (20 grams) of cyanobacterial bloom from Bueng Nong Khot, Khon Kaen province was extracted and purified and a mixture of microcystins (MCs) were identified. The toxins were purified with DEAE and Strata-X SPE cartridge chromatography and identified by reversed-phase HPLC with photodiode-array UV detection (UVD) and liquid chromatography-tandem mass spectrometry (LC-MS). Chemical characterization of the lyophilized cells revealed three variants of MCs, including MC-RR; MC-FR and [Dha7]MC-LR) of which [Dha7]MC-LR was the major variant extracted with a purity of 93% and yield of 25.38 mg. [Dha7]MC-LR is MC-LR which is the loss of a methyl group which occurs at the amino acid, Mdha, resulting in [Dha7]MC-LR The main variant appears to be [Dha7]MC-LR not MC-LR as seen in lakes overseas. These toxins have been implicated in animal deaths and human illness. They are extremely stable and may persist in water bodies for several weeks. Knowledge of the MC-variants present in the water bodies will help in further investigations in eliminating them.


P.034-042

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Antioxidant Activities and Total Phenolic Contents from Thai Wild Fruits

ฤทธิ์การต้านอนุมูลอิสระและปริมาณสารประกอบฟีนอลรวมจากผลไม้ป่าของไทย

Pakit Kumboonma* and Sudarat Sombatsri

The objective of this research was to study the total phenolic contents and the antioxidant activities of selected ten Thai wild fruits including Flacourtia indica, Micromelum minutum, Antidesma ghaesembilla, Vitex glabrata, Catunaregam tomentosa, Strychnos nuxblanda, Diosyios rhodcalyx, Spondias pinnata, Tiliacora triandra and Schleichera oleosa. All samples were extracted with dichloromethane, ethyl acetate and methanol. The total phenolic contents using the Folin-Ciocalteu reagent and the antioxidant activities using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, reducing power and iron (II) chelation of all extracts were evaluated. The total phenolic contents of the ethyl acetate extract of F. indica possessed the highest quantity of total phenolic compounds as 915.63+4.66 mg GAE/g extract. Moreover, the ethyl acetate extract of F. indica showed the strongest DPPH inhibition with the IC50 of 3.94+0.01 µg/mL. In addition, the ethyl acetate extract of F. indica exhibited strong ferric reducing power and ferrous chelation activity with the value of 375.14+8.39 mmol/g extract and 124.51+1.07 mmol/g extract, respectively. The methanolic extract of S. pinata indicated very strong DPPH inhibition with the IC50 of 3.97+0.06 µg/mL. Furthermore, the methanolic extract of S. pinata showed strong reducing power and ferrous chelation activity with the values of 366.02+12.27 mmol/g extract and 105.70+1.21 mmol/g extract, respectively. Therefore, these fruits can be further used as sources of antioxidants for food and pharmacological application.


P.044-052

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Karyological characteristics of Amphiprion frenatus and Premnas biaculeatus (Perciformes, Amphiprioninae)

การศึกษาลักษณะแคริโอไทป์ของปลาการ์ตูนมะเขือเทศและปลาการ์ตูนแก้มหนาม

Nuntaporn Getlekha and Alongklod Tanomtong*

The karyotypic characteristics of tomato anemonefish, Amphiprion frenatus and spine cheek anemonefish, Premnas biaculeatus from Andaman sea, Southern of Thailand were obtained from the present study. The mitotic chromosomes were prepared by direct method from kidney tissues after in vivo colchicine treatment. Conventional staining technique was used to stain the metaphase chromosome with Giemsa’s solution. The results showed that the diploid chromosome number (2n) of A. frenatus and P. biaculeatus were 48, with the fundamental numbers (NF) being 94 in both males and females. The chromosomes of A. frenatus and P. biaculeatus present metacentric, submetacentric, acrocentric, and telocentric chromosomes as 16-20-10-2 and 14-26-6-2, respectively. No morphologically differentiated sex chromosomes were detected in both sexes. The karyotype formulae were as follows:

     A. frenatus; 2n (48) = Lm10+Lsm14+ La10+Lt2+Mm6+Msm6

                       2n (48) = 16m+20sm+10a+2t

    P. biaculeatus; 2n (48) = Lm6+Lsm10+ La4+Mm8+Msm16+Ma2 Mt2

                          2n (48) = 14m+26sm+6a+2t

 


P.053-061

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Chemical Constituents from Glycosmis pentaphylla Stems

องค์ประกอบทางเคมีจากลำต้นเขยตาย

Suwadee Chokchaisiri, Yuttana Siriwattanasathien and Thitima Rukachaisirikul*

Phytochemical investigation of the stems of Glycosmis pentaphylla led to the isolation of eleven known compounds, including bisglybomine B (1), glybomine B (2), carbalexin C (3), glycoborinine (4), skimmianine (5), robustine (6), g-fagarine (7), arborinine (8), N-p-trans-coumaroyltyramine (9), 2-(N-methyl-2-phenylacetamido) benzoic acid (10) and (-)-syringaresinol (11). All structural assignments were made by comparing the NMR spectral data of the pure isolates with that published in the quoted literature. Among them, compound 10 was firstly purified as a natural product and compounds 10 and 11 were isolated from the genus Glycosmis for the first time. Some isolates were evaluated for anti-acetylcholinesterase activity.


P.062-068

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Chemical Composition and Biological Activity of Bixa orellana L. Leaf Essential Oil

องค์ประกอบทางเคมีและฤทธิ์ทางชีวภาพของน้ำมันหอมระเหยใบคำแสด

Sawitree Kathongthung

The leaves of Thai Annatto Tree (Bixa orellana L.) were subjected to water distillation followed by analysis of the essential oil constituents using GC-MS technique as well as antibacterial activity test. The percent of extraction of the essential oil was found to be 1.04. GC-MS analysis showed the presence of phytochemicals such as terpenoids, sesquiterpenes and aromatic compounds. The antibacterial test of the essential oil showed the activity against Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis. The average diameter of inhibition zone of E. coli, S. aureus and S. epidermidis were 12.0±0.2, 11.0±0.1 and 12.5±0.3 respectively. In conclusion, the essential oil of Annatto leaf showed biological activity against E. coli, S. aureus and S. epidermidis with the presence of some biological active compounds such as 1H-Cycloprop[e]azulene or (-)-alpha-Gurjunene, camphor, D-germacrene and guaiacol.


P.069-080

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Microscopical characters, total phenolic content, and antioxidant activity of Albizia myriophylla Benth.

จุลทรรศน์ลักษณะ ปริมาณฟีนอลรวม และฤทธิ์ต้านอนุมูลอิสระของชะเอมไทย

Nazneen Bakasatae, Narkis Yapa, Vitsarut Issalamikkun, Papawarin Issarachote, Oraphan Sakulkeo, and Nantiya Joycharat*

Albizia myriophylla Benth. of Fabaceae family is a medicinal plant used in southern Thailand. It is used as a medicinal ingredient in various preparations for the treatment of caries, diabetes and dermatitis. The investigation of microscopic character of 3 collections (VI01 VI02 and VI03) of A. myriophylla in southern Thailand led to the identification of ray parenchyma, ray parenchyma with starch grains, ray parenchyma with prism of calcium oxalate, border-pitted vessels, phloem fibers, phloem parenchyma with starch grains, fibers with calcium oxalate prism, stone cell, prisms of calcium oxalate, and starch grains in their powdered drugs. The most common tissues in powdered drugs of the 3 collections of A. myriophylla were starch grains, border-pitted vessels, and  phloem parenchyma with starch grains. From DPPH and FRAP methods, the ethanol extract (DPPH, IC50 46.23-67.95 µg/mL; FRAP, 380.53-847.31 mM FeSO4/g) from all 3 collections of A. myriophylla showed higher antioxidant capacity than the water extract (DPPH, IC50 53.53-67.95 µg/mL; FRAP, 239.78-377.05 mM FeSO4/g) of this plant. Among the extracts of 3 collections of A. myriophylla, VI01 extract showed the best antioxidant activity. The total phenolic content of the extracts from 3 collections of A. myriophylla was analyzed using spectrophotometry. The results have revealed that the total phenolic content in VI01, VI02, and VI03 extracts was in accordance with their antioxidant activity in DPPH and FRAP assays. In this case, the ethanol extracts of all 3 collections had higher total phenolic content than their water extracts. VI01 appeared to have higher total phenolic content than the others. Furthermore, it was found that the water extract from VI01 had total phenolic content and good antioxidant activity similar to that containing A. myriophylla and licorice (Glycyrrhiza glabra L.). In this study, the ethanol extract containing A. myriophylla and G. glabra had the highest total phenolic content and demonstrated good antioxidant activity compared to the others tested. Our results provide preliminary scientific data related to the use of A. myriophylla wood as a raw material in Thai traditional medicine for the treatment of oxidative stress associated diseases.


P.081-092

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Influence of milling methods on physicochemical properties of Thai rice flour (Riceberry) and its application for gluten free crispy waffle

อิทธิพลของการโม่ต่อสมบัติทางเคมีและกายภาพของแป้งข้าวไรซ์เบอร์รี่ และการนำไปประยุกต์ใช้ในผลิตภัณฑ์วาฟเฟิลกรอบปลอดกลูเตน

ศันสนีย์ อุดมระติ* พัชรี ตั้งตระกูล และ งามจิตร โล่วิทูร

The objectives of this research are to study the effect of milling methods (dry milling and semi-dry milling) on components and physicochemical properties of rice flour (Riceberry) and to utilize Riceberry flour in gluten free crispy waffle recipe, replacing wheat flour. Dry-milled riceberry flour contained higher protein content, damaged starch (%) and water absorption index (WAI), compared to semi-dry milling. There was no difference in amylose content of both milled samples. The larger average particle size was found in semi-dry-milled sample, which contained the large particle of fiber and small particle of starch granules as observed by microscope. For pasting properties, pasting temperature, final viscosity, and setback of dry-milled riceberry flour showed the higher values than those of semi-dry-milled sample, while the values of peak viscosity and breakdown of dry-milled flour were lower values than semi-dry-milled flour. In terms of gelatinization and retrogradation, semi-dry-milled riceberry flour consumed larger energy for gelatinization (DHgel) and showed lower temperatures of gelatinization (Togel, Tpgel, and Tcgel), compared to dry-milled flour. There were small differences in energy (DHretro) and temperatures (Toretro, Tpretro, and Tcretro) of retrogradation of both milled riceberry flour gels after storaged at refrigerated temperature for 7 days. The lower hardness and stickiness values of semi-dry-milled riceberry gel were observed. For utilization, semi-dry-milled riceberry flour may be more suitable ingredient in gluten free crispy waffle, compared to dry-milled rice flour and has potential to replace wheat flour, in term of texture.


P.093-100

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Diversity of the Stingless Bees (Apidae: Meliponini) in Surat Thani Province

ความหลากชนิดของชันโรงในจังหวัดสุราษฎร์ธานี

จิตเกษม หลำสะอาด* เกษร เมืองทิพย์ และวสันต์ สุทธโส

This research was aimed to survey, collect and identify the stingless bee sampled from Surat Thani Province, to identify the plants species in which the stingless bees build their nests upon, and interview local people on how they utilize the stingless bee’s products. The survey sites of 18 District in Surat Thani were random. Within each District 9 agricultural areas, 3 urban areas were chosen. The results are: 1) From 251 samples, six genera and twelve species of stingless bee in the Family Apidae were identified. Eight species were found in Chiya District. The nests of Tetragonilla collina (Smith), Tetragonula pegdeni (Schwarz) were found in every District. While all 12 species could be found in agricultural areas. T. collina (Smith), Tetragonula fuscobalteata (Cameron), T. pegdeni (Schwarz) could be found in both areas. They build their nests within tree stumps, cracks on cement, brick walls, and inside any discarded tools; 2) the nests were found on 19 families 22 genus 28 species of plant in which the most occurrence was found in the Family Moraceae; 3) The nest’s entrance of each species is different; 4) the local people use the stingless bee wax to made handle of betel nut pounder, knife hilt, boat sealant, treat infected wound, and as an ingredient in herbal medicine.


P.101-109

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Diversity and Utilization of Costaceae in Thailand

ความหลากหลายและการใช้ประโยชน์ของพืชวงศ์เอื้องหมายนาในประเทศไทย

พิมธิดา นาทุ่งมล สุรพล แสนสุข* ปิยะพร แสนสุข

Diversity and utilization of family Costaceae in Thailand is studied between January and December 2016. Dried specimens at BK, BKF, QBG and PSU herbaria were studied. The specimens of the Costaceae were collected from all regions in Thailand. Two genera and 5 species were recorded. There are genus Costus with two species and genus Hellenia with three species. Among there one rare species, H.  lacera (Gagnep.) Govaerts, is reported. Moreover, one vulnerable species, H. globosa (Blume) S.R. Dutta, are reported and C. woodsonii Maas is recorded as least concern (LC) species. Most species of this family are distributed in hill evergreen forest, evergreen forest, swamp forest, deciduous forest, mixed deciduous dipterocarp forest and savanna with altitude 0-2,536 m about sea level. In addition, utilization of Costaceae in Thailand. By the way, interview the folk philosopher, doctors of folk medicine and villagers in the areas where the plants used. It has been used in the food (1 species), medicine (2 species), ritual plant (1 species), and most family Costaceae all five species are used an ornamental plants.


P.110-116

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Relationship between phytoplankton and water qualities at Ao Nok, Chanthaburi Province

ความสัมพันธ์ระหว่างแพลงก์ตอนพืชและคุณภาพน้ำบริเวณอ่าวนก จังหวัดจันทบุรี

วรรณวิภา เกียรติพิริยะ เบ็ญจมาศ ไพบูลย์กิจกุล สุพัทรา อัฐนาค อริษา ภาบุตร และ ชลี ไพบูลย์กิจกุล*

The purpose of this study was to investigate the relationship between phytoplankton and water qualities at Ao Nok, Chanthaburi Province from December 2012 to August 2013. Phytoplankton and water qualities were collected every three months in 7 stations. The result of this study illustrated that 165 species of phytoplankton in 4 divisions had been found composed of 9 genera of Division Cyanophyta, 37 genera of Division Chlorophyta, 3 genera of Division Pyrrophyta and 116 genera of Division Chromophyta. Phytoplankton in Class Bacillariophyceae was the dominant species. The dominant genera of this study were Bacteriastrum sp., Ceratium sp., Chaetoceros sp., Coscinodiscus sp., Nitzschia sp., Odontella sp., Pleurosigma sp., Rhizosolenia sp., Surirella sp., Thalassionema sp., and Thalassiothrix sp. Phytoplankton division changed by season. Average phytoplankton density was 4.04x104 unit/l. The high density of phytoplankton had been found the station near the river mouth in winter because of the high concentration of total ammonia and orthophosphate.


P.117-126

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The Simple Natural Indigo fabric test kit by Column Chromatography

ชุดทดสอบผ้าย้อมครามธรรมชาติอย่างง่ายด้วยเทคนิคคอลัมน์โครมาโทกราฟี

อรทัย แสงวงค์ ทิชานันท์ พะวงค์ ภีระพัฒน์ ปัดทุมมา และ ศุภกร อาจหาญ*

Indigo fabric has blue or indigo color from various sources such as natural, synthesized indigo dyes and other blue dye. From the varieties of indigo color sources, determination of major chemical composition by Chromatography technique, UV-visible spectroscopy and Fourier transforms infraredspectroscopy found that the main colors obtained in the natural indigo fabric were blue and red of indigo blue and indirubin, respectively. Meanwhile, the synthesized indigo fabric has only indigo blue, and indirubin was not found. From these results, this research invented a simple test-kit for identify the kinds of indigo fabric. Moreover, this test-kit is inexpensive, and easy to use when compared with the complicate scientific instrument.


P.127-133

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Effect of Pretreatment and Drying Methods on Physicochemical and Sensory Properties of Dried Kaffir Lime Leaves

ผลของการเตรียมวัตถุดิบขั้นต้นและวิธีการอบแห้งต่อสมบัติทางเคมีกายภาพ และทางประสาทสัมผัสของใบมะกรูดอบแห้ง

ณัฐวดี มาลา และ สุจินดา ศรีวัฒนะ*

The objective of this research was to obtain the optimal pretreatment and drying methods in order to improve color and odor of dried kaffir lime leaves. A 3 x 3 factorial design was performed to investigate pretreatment methods (no pretreatment, blanching in magnesium carbonate and blanching in salt solution then soaking in potassium metabisulfite) and drying methods (hot air oven at 50 °C for 6 hours, microwave vacuum at 4,800 watt for 30 min, and fluidized bed at 60 °C for 2 hrs). Result showed that pretreatment and drying methods affected color value L* a* b*, citronellal content and liking scores (p≤0.05). Kaffir lime leaves pretreated with both of blanching in magnesium carbonate and blanching in salt solution then soaking in potassium metabisulfite had citronellal content more than that of no pretreatment. Kaffir lime leaves dried with microwave vacuum drying had citronellal content and liking scores higher than those of the other drying methods. Optimal drying condition for kaffir lime leaves which had the highest citronellal content and liking scores in term of color and odor was blanching in magnesium carbonate and then dried with microwave vacuum at 4,800 watt for 30 min.


P.134-143

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Energy Resolution of the GAGG:Ce Scintillation Crystal for Gamma-ray Detection

ค่าแยกชัดพลังงานของผลึกซินทิลเลชัน GAGG:Ce สำหรับการตรวจวัดรังสีแกมมา

อัคคพงศ์ พันธุ์พฤกษ์* วรนุศย์ ทองพูล และ ศราวุธ ใจเย็น

The GAGG:Ce is a new scintillation crystal which is getting the attention of scientists now because this crystal was developed to be very high light yield, high density, and non-hygroscopic crystal, which is suitable for use in medical diagnostics and research in high energy physics. In this work, we tested the energy resolution property of the crystal for gamma-ray detection comparing with the classical one, the BGO crystal. Both crystals are tested with gamma ray sources ranging from 31 keV to 1,408 keV. At 662 keV energy from the Cs-137 radioactive source, the energy resolution of the GAGG:Ce crystal is 7.11%, which is better than 9.28% obtained from the BGO crystal. The light yield of the GAGG:Ce crystal is 41,300 ph/MeV which more than that of the BGO crystal about 5 times. From the experiment result, the energy resolution of both crystals strongly relates to their intrinsic resolution and light yield non-proportionality. Since the GAGG:Ce crystal possesses many good properties, it has a high potential to replace old crystals, especially in medical imaging and high energy physics research.


P.144-153

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Mathematical Models Developing of Different Pattern of Dried Agricultural Products

การพัฒนาแบบจำลองทางคณิตศาสตร์ของผลิตภัณฑ์เกษตรอบแห้งรูปร่างแตกต่างกัน

อาภาภรณ์ จอมหล้าพีรติกุล* และ ประยูร จอมหล้าพีรติกุล

The objective of this research was to develop a mathematical model for different pattern of agricultural products drying by hot air based on 3D heat transfer and mass diffusion with the finite element method and COMSOL MULTIPHYSICS software to determine moisture distribution, drying time, shrinkage, energy consumption and specific moisture evaporation rate (SMER). The study was conducted by using drying temperature levels at 60, 70 and 80 °C. The samples were two patterns of 1 cm3 volume carrots. They were 0.5x0.5x4 cm3 and 0.5x2x1 cm3. The results indicated that the shrinkage values of two patterns were slightly different at over 150 minutes drying time. In terms of energy consumption, the 0.5x0.5x4 cm3 size at a drying temperature of 60 °C had the lower energy consumption which was 37 kJ and the higher SMER value which was 1.95 kg / kWh. When moisture and shrinkage values of the model and the experiment were compared, the small errors were found with acceptability.


P.154-166

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The effect of children under five-year old with hygiene care and breastfeeding on dynamics of pneumonia model for Thailand

ผลของการดูแลสุขลักษณะและการเลี้ยงดูบุตรด้วยนมแม่ต่อพลวัตของแบบจำลอง ทางคณิตศาสตร์โรคปอดอักเสบสำหรับเด็กอายุต่ำกว่า 5 ขวบในประเทศไทย

Ratchada Viriyapong* and Sureerat Kamyod

Pneumonia is a respiratory disease that is mainly caused by virus infection. It is mostly found in children more than adults and it is one of the leading causes of serious illness and deaths among children under five years old around the world including Thailand. In this paper we develop a deterministic model of the transmission dynamics of pneumonia with the possibility of infection resistance of children with breastfeeding together with the impact of hygiene care of susceptible group. The conditions for the clearance and persistence of the pneumonia infection through the stability of the equilibria are derived. The basic reproduction number and its sensitivity are calculated. Stability of equilibrium points indicates that the basic reproduction number has to be maintained at the level less than unity in order to eliminate the disease. Sensitivity analysis of basic reproduction number and numerical simulation demonstrates that the immunity to disease due to breastfeeding and hygiene care of children should be encouraged in order to achieve a disease-free population.


P.167-176

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An Improvement of ElGamal-like Cryptosystem with Periodic Bitwise Operations

การปรับปรุงระบบรหัสลับเอ็ลกามอลไลก์ด้วยตัวดำเนินการทีละบิตแบบเป็นคาบ

Wanchaloem Nadda and Thotsaphon Thongjunthug*

Hwang et al. (2002) proposed an ElGamal-like cryptosystem which aimed to improve effectiveness of the ElGamal cryptosystem for encrypting large messages, particularly in terms of computational complexity and the storage of ciphertext. Later, Wang et al. (2006) proved that the ElGamal-like cryptosystem is less secure than the ElGamal cryptosystem, and then proposed an improved version to increase the security. In this paper, we improve the scheme of Wang et al. (2006) by using different bitwise operations, which are assigned according to a certain periodic sequence, while encrypting different blocks of plaintext. The results show that our scheme can provide larger period length of the coefficients for encryption and more resistance to a ciphertext-only attack and a known-plaintext attack than the scheme of Wang et al. (2006).


P.177-185

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Sensitivity Comparison of EWMA Max-GWMA and Max-CUSUM Control Charts for Exponential distribution

การเปรียบเทียบความไวของแผนภูมิควบคุม EWMA Max-GWMA และ Max-CUSUM สำหรับการแจกแจงแบบเลขชี้กำลัง

คณิตา เพ็ชรัตน์

The objective of this article is to compare the sensitivity of EWMA Max-GWMA and Max-CUSUM control charts for exponential distribution. The performance of control charts are measured by average run length (ARL).  Monte-Carlo simulation method is used for evaluate ARL of EWMA Max-GWMA and Max-CUSUM control charts with 10,000 iterations. The results show that when process when observations are exponential distribution, for  EWMA control chart is sensitive for small changes and Max-GWMA control chart with is sensitive for moderate changes . For  Max-GWMA control chart with is sensitive for small changes  and EWMA control chart is sensitive for moderate changes.