Preliminary Studies on CPG/Hinf Ⅰ RFLP Groups of Citrus tristeza virus Infected Sweet Oranges in China

Citrus tristeza virus （CTV） causes economically important losses to the citrus industry worldwide. Mild strain cross protection （MSCP） against tristeza has hardly been practised due to mixed infection of different CTV-strains and little background of its molecular biology in China. For better cognition on CTV, 192 sweet orange samples collected from eight provinces （Chongqing, Sichuan, Fujian, Hunan, Guangxi, Yunnan, Guangdong and Jiangxi） were tested by direct tissue blot immuno-assay （DTBIA）, and 158 of them were tested positively, which therefore were subjected to coat protein gene （CPG）/Hinf Ⅰ restriction fragment length polymorphism （RFLP） analysis. Sample bulks were compared between Chongqing and Fujian by some statistical data, including ratios of single infection and mixed infection to local samples, proportions of CTV isolates with single RFLP groups, and rates of each RFLP group. The simplified analysis of samples from the other six provinces were then conducted. This study suggests that CTV isolates with CPG/Hinf Ⅰ RFLP groups Ⅲ and Ⅰ are the main epidemic ones in China, and mixed infection of CTV in fields are popular. Based on observation of severity of stem-pitting symptom in field trees, CTV isolates with CPG/Hinf Ⅰ RFLP groups Ⅲ and Ⅰ caused severe stem-pittings in sweet oranges in China.

Isolation and Purification of Anthocyanins from Blood Oranges by Column Chromatography

In this study, isolation and purification of anthocyanins from blood oranges by column chromatography were investigated, and then the anthocyanins of blood orange were identified. The behaviors of static adsorption and desorption, dynamic adsorption and desorption of 12 kinds of resins were compared. The results indicated that NKA-9 macroporous resin was optimum for isolation of blood orange anthocyanins, and the optimal elution reagent was 50% ethanol with citric acid （pH 2.5）. Toyopearl TSK HW-40S column was employed to separate and purify the anthocyanin extracts from blood orange. The best separation of Toyopearl TSK HW-40S column was obtained using a mobile phase of 35% methanol with 2% formic acid at a flow-rate of 0.6 mL min-~. Three kinds of anthocyanins were purified from blood orange. Then, the anthocyanins of blood orange were identified by HPLC-ESUMS analysis. The results showed that cyanidin-3-glucoside （35.2%） and cyaniding-3-（6＂-malonyl） glucoside （42.9%） were the major anthocyanins of blood orange. Furthermore, cyanidin-3-（3＂-malonyl） glucoside, cyanidin 3-（6＂-dioxalyl） glucoside and cyanidin-3-glucoside adduct：4-vinylcatechol were identified in blood orange. The combination of NKA-9 macroporous resin and Toyopearl TSK HW-40S column chromatography for isolation and purification of blood orange anthocyanins was an effective method, and HPLC-ESI/MS analysis was a convenient, rapid and effective method for identification of anthocyanins from blood orange.

Changes in phenolic content,composition,and antioxidant activity of blood oranges during cold and on-tree storage

Citrus fruits are rich in phenolic compounds that possess several health benefits.However,few studies have focused on the changes in phenolic compounds in citrus fruits during postharvest storage.This study dynamically monitored the phenolic content,components and antioxidant activity of‘Tarocco’blood oranges during a period of 12-week cold storage and on-tree storage,respectively.We investigated the alteration mechanism of phenolic compounds in blood oranges by evaluating phenylpropanoid pathway-related enzyme activities and gene expression.Results showed that flavanones were the main phenolic compounds in blood oranges.Both storage methods mainly stimulated the accumulation of phenolic acids to improve total phenolic content,which reached the maximum at week 12.Nonetheless,blood oranges had a higher phenolic content and antioxidant activity under on-tree storage than cold storage.Furthermore,the enzyme activities and gene expression of the phenylpropanoid pathway demonstrated that the accumulation of phenolics in blood oranges during storage was highly related to the activation of the phenylpropanoid pathway.These results demonstrate that on-tree storage is a potential approach for extending the supply period of blood orange from the perspective of phenolic compounds.

In Vitro Development and Germination of Immature Embryos of Sweet Oranges Parson Brown and Pineapple(Citrus sinensis)

Oranges are classified as the most traded fruit variety worldwide.The diversification of the varietal profile of this group is among the objectives of the Citrus breeding program.So,the creation of new triploid hybrids via immature embryos rescue,can lead to an increase in gene pool and produce seedless varieties.In addition,flow cytometry was successfully used for analyzing ploidy levels and genetic origin of triploid plants.The present study was aimed at optimizing immature embryos in vitro germination and plantlet development based on medium chemical composition of the two orange varieties,Pineapple and Parson Brown.When the fruit gets matured,they are harvested and the seeds extracted are classified according to their size.Only those which are small are cultured in a sterile Murashige and Tucker(MT)basal medium.The different concentrations of growth regulators are put to the test in order to gain the best medium for seeds development.M1(MT+1 mg/L gibberellic acid(GA3)),M2(MT+1 mg/L kenitin+0.5 mg/L 6-benzylaminopurine(BAP)+0.1 naphthalene acetic acid(NAA)),M3(MT+25 mg/L adenine sulfate(ADS)),M4(MT+0.5 mg/L kenitin+0.5 mg/L BAP+1 mg/L GA3).Percentage of germinated embryos(PGE)is the highest in M3 with 100%and 90%for both Pineapple and Parson Brown varieties,respectively.In addition,the germination interval average(GIA)is shorter in M1 for both varieties,which takes 6 d and 7 d,respectively.As regard to speed seedling growth(mm/week),both varieties undergo significant change in all four mediums.Similarly,the highest rate of acclimatization for the Pineapple and Parson Brown varieties is 80%and 90%in M1.In general,the smaller the embryos are,the more sensitive they are to culture medium composition.It is therefore essential to optimize the medium components in order to stimulate their in vitro development.Therefore,M1(MT+1 mg/L GA3)remains the best to promote short term good germination and produce a better rate of acclimatization.

Global analysis of basic leucine zipper transcription factors in trifoliate orange and the function identification of PtbZIP49 in salt tolerance

As one of the most widely distributed and highly conserved transcription factors in eukaryotes,basic leucine zipper proteins(bZIPs)are involved in a variety of biological processes in plants,but they are largely unknown in citrus.In this study,56 bZIP family members were identified genome-wide from an important citrus rootstock,namely trifoliate orange(Poncirus trifoliata L.Raf.),and these putative bZIPs were named PtbZIP1—PtbZIP56.All PtbZIPs were classified into 13 subgroups by phylogenetic comparison with Arabidopsis thaliana bZIPs(AtbZIPs),and they were randomly distributed on nine known(50 genes)chromosomes and one unknown(6 genes)chromosome.Sequence analysis revealed the detailed characteristics of PtPZIPs,including their amino acid length,isoelectric point(pI),molecular weight(MW),predicted subcellular localization,gene structure,and conserved motifs.Prediction of promoter elements suggested the presence of drought,low-temperature,wound,and defense and stress responsive elements,as well as multiple hormone-responsive cis-acting elements.Spatiotemporal expression analysis showed the transcriptional patterns of PtbZIPs in different tissues and under dehydration,high salt,ABA,and IAA treatments.In addition,21 PtbZIPs were predicted to have direct or indirect protein—protein interactions.Among these,PtbZIP49 was experimentally proven to interact with PtbZIP1 or PtbZIP11 by using a yeast two-hybrid assay and bimolecular fluorescence complementation(BiFC).Subcellular localization analysis further revealed that PtbZIP1,PtbZIP11,and PtbZIP49 were localized in the nucleus.Moreover,PtbZIP49 was functionally identified as having an important role in salt stress via ectopic expression in A.thaliana and silenced in trifoliate orange using virus-induced gene silencing(VIGS).This study provided comprehensive information on PtbZIP transcription factors in citrus and highlights their potential functions in abiotic stress.

High-Performance Organic Field-Effect Transistors Based on Two-Dimensional Vat Orange 3 Crystals

The exploration and research of low-cost,environmentally friendly,and sustainable organic semiconductor materials are of immense significance in various fields,including electronics,optoelectronics,and energy conversion.Unfortunately,these semiconductors have almost poor charge transport properties,which range from∼10^(−4) cm^(2)·V^(−1)·s^(−1) to∼10^(−2) cm^(2)·V^(−1)·s^(−1).Vat orange 3,as one of these organic semiconductors,has great potential due to its highly conjugated structure.We obtain high-quality multilayered Vat orange 3 crystals with two-dimensional(2D)growth on h-BN surfaces with thickness of 10–100 nm using physical vapor transport.Raman’s results confirm the stability of the chemical structure of Vat orange 3 during growth.Furthermore,by leveraging the structural advantages of 2D materials,an organic field-effect transistor with a 2D vdW vertical heterostructure is further realized with h-BN encapsulation and multilayered graphene contact electrodes,resulting in an excellent transistor performance with On/Off ratio of 104 and high field-effect mobility of 0.14 cm^(2)·V^(−1)·s^(−1).Our results show the great potential of Vat orange 3 with 2D structures in future nano-electronic applications.Furthermore,we showcase an approach that integrates organic semiconductors with 2D materials,aiming to offer new insights into the study of organic semiconductors.

Green Synthesis of Silver Nanoparticles Using Aqueous Orange and Lemon Peel Extract and Evaluation of Their Antimicrobial Properties

Green synthesis of silver nanoparticles (AgNPs) using aqueous extracts of orange and lemon peels, as a reducing agent, and silver nitrate salts as a source of silver ions is a promising field of research due to the versatility of biomedical applications of metal nanoparticles. In this paper, AgNPs were synthetized at different reaction parameters such as the type and concentration of the extracts, metal salt concentration, temperature, speed stirring, and pH. The antibacterial properties of the obtained silver nanoparticles against E. coli, as well as the physical and chemical characteristics of the synthesized silver nanoparticles, were investigated. UV-Vis spectroscopy was used to confirm the formation of AgNPs. In addition to green biogenic synthesis, chemical synthesis of silver nanoparticles was also carried out. The optimal temperature for extraction was 65˚C, while for the synthesis of AgNPs was 35˚C. The synthesis is carried out in an acidic environment (pH = 4.7 orange and pH = 3.8 lemon), neutral (pH = 7) and alkaline (pH = 10), then for different concentrations of silver nitrate solution (0.5 mM - 1 mM), optimal time duration of the reaction was 60 min and optimal stirring speed rotation was 250 rpm on the magnetic stirrer. The physical properties of the synthesized silver nanoparticles (conductivity, density and refractive index) were also studied, and the passage of laser light through the obtained solution and distilled water was compared. Positive inhibitory effect on the growth of new Escherichia coli colonies have shown AgNPs synthesized at a basic pH value and at a 0.1 mM AgNO3 using orange or lemon peel extract, while for a 0.5 mM AgNO3 using lemon peel extract.

An Analysis of Specific Categories of Birth Defects and Developmental Disabilities for Children of Participants of the Air Force Health Study

Background: The Air Force Health Study collected reproductive outcomes for live-born children of male Air Force veterans of the Vietnam War. Methods: Dioxin values for participants were obtained from blood samples. Analyses were conducted of occurrence of 16 specific categories of birth defects and developmental disabilities. Children were categorized as conceived before and after the start of participants’ Vietnam War service. Children conceived before the start of Vietnam War service were treated as being conceived when their fathers had unquantifiable dioxin values. Children conceived after the start of Vietnam War service for participants with missing dioxin values were excluded from primary analyses, but were used to assess the impact of their exclusion on conclusions. Correlation between values for specific categories for multiple children fathered by the same participant was accounted for. The dose-response relationship was treated as a step function increasing for dioxin values larger than adaptively identified individual thresholds changing with the specific category. Results: For 15 of 16 specific categories, the probability of occurrence increased substantially for a sufficiently high dioxin level above identified thresholds. Exclusion of children due to missing dioxin likely did not affect these results. Conclusions: Results supported the conclusion of substantial adverse effects on a wide variety of specific categories of birth defects and developmental disabilities due to sufficiently high exposures to dioxin, a toxic contaminant of Agent Orange used for herbicide spraying in the Vietnam War. Results may hold more generally, but might also have been affected by a variety of limitations.

Color of the Year 2024: Peach Fuzz

Pantone has declared Pantone 13-1023Peach Fuzz as its Color of the Year for 2024.This soft peach tone reflects comforting warmth and represents a desire for unity,peace and personal well-being.The calming shade,a sublime blend of pink and orange,suggests fresh softness,signifying an environment that invites relaxation,reccovery and growth.The delicatehue of Pantone 13-1023 Peach Fuzz not only awakens our senses to the tactile and enveloping warmth of the color,but also influences our sense of peace and overall well-being.

基于数据挖掘的思政理论资源个性化推荐系统设计

由于传统系统存在新用户推荐及推荐效果较差的问题,提出一种基于数据挖掘的思政理论资源个性化推荐系统。硬件中服务器模块共由22台服务器构成。处理器模块选用的是S3C3210x处理器。软件中数据挖掘模块主要利用Orange工具箱来实现思政理论资源的数据挖掘。数据处理模块能够实现资源数据的转换与爬取、降维处理。资源个性化推荐模块主要通过混合推荐技术实现个性化推荐。数据库模块中包括用户兴趣表、资源信息表、用户信息表。以此进行性能测试。实验结果表明,其推荐效果优于传统系统,可实现新用户的个性化推荐。

Fiber-specific increase of carotenoid content promotes cotton fiber elongation by increasing abscisic acid and ethylene biosynthesis

Cotton fiber is a raw material for the global textile industry and fiber quality is essential to its industrial application.Carotenoids are plant secondary metabolites that may serve as dietary components,regulate light harvesting,and scavenge reactive oxygen species.Although carotenoids accumulate predominantly in rapidly elongating cotton fibers,their roles in cotton fiber development remain poorly understood.In this study,a fiber-specific promoter proSCFP was applied to drive the expression of GhOR1Del,a positive regulator of carotenoid accumulation,to upregulate the carotenoid level in cotton fiber in planta.Fiber length,strength,and fineness were increased in proSCFP:GhOR1Del transgenic cotton and abscisic acid(ABA)and ethylene contents were increased in elongating fibers.The ABA downstream regulator GhbZIP27a stimulated the expression of the ethylene synthase gene GhACO3 by binding to its promoter,suggesting that ABA promoted fiber elongation by increasing ethylene production.These findings suggest the involvement of carotenoids and ABA signaling in promoting cotton fiber elongation and provide a strategy for improving cotton fiber quality.

Single-cell RNA sequencing reveals gonadal dynamic changes during sex differentiation in hermaphroditic protogynous orange-spotted grouper(Epinephelus coioides)

DEAR EDITOR,Sex differentiation is a complex process that requires many factors to regulate gonadal proliferation, differentiation,development, and organization. In teleosts, the molecular mechanisms of sex differentiation are diverse and unclear.

Chromosome-level genome assembly of Salvia miltiorrhiza with orange roots uncovers the role of Sm2OGD3 in catalyzing 15,16-dehydrogenation of tanshinones

Salvia miltiorrhiza is well known for its clinical practice in treating heart and cardiovascular diseases.Its roots,used for traditional Chinese medicine materials,are usually brick-red due to accumulation of red pigments,such as tanshinone IIA and tanshinone I.Here we report a S.miltiorrhiza line(shh)with orange roots.Compared with the red roots of normal S.miltiorrhiza plants,the contents of tanshinones with a single bond at C-15,16 were increased,whereas those with a double bond at C-15,16 were significantly decreased in shh.We assembled a high-quality chromosome-level genome of shh.Phylogenomic analysis showed that the relationship between two S.miltiorrhiza lines with red roots was closer than the relationship with shh.It indicates that shh could not be the mutant of an extant S.miltiorrhiza line with red roots.Comparative genomic and transcriptomic analyses showed that a 1.0 kb DNA fragment was deleted in shh Sm2OGD3m.Complementation assay showed that overexpression of intact Sm2OGD3 in shh hairy roots recovered furan D-ring tanshinone accumulation.Consistently,in vitro protein assay showed that Sm2OGD3 catalyzed the conversion of cyptotanshinone,15,16-dihydrotanshinone I and 1,2,15,16-tetrahydrotanshinone I into tanshinone IIA,tanshinone I and 1,2-dihydrotanshinone I,respectively.Thus,Sm2OGD3 functions as tanshinone 15,16-dehydrogenase and is a key enzyme in tanshinone biosynthesis.The results provide novel insights into the metabolic network of medicinally important tanshinone compounds.

CsTT8 regulates anthocyanin accumulation in blood orange through alternative splicing transcription

A homologous gene of basic-helix-loop-helix AtTT8 in Arabidopsis thaliana was identified in juice sac cells of pulp tissues from blood orange(Citrus sinensis cv‘Tarocco’),which was designated as CsTT8 in this study.Additionally,the mRNA levels of TT8 with the full-length open reading frame were significantly higher in‘Tarocco’than in mutant fruit lacking pigment in pulp or peel tissues.However,an alternative splicing transcript,Δ15-TT8,with the fourth exon skipped,was also identified from transcripts different in length from that in‘Tarocco’.The mRNA levels ofΔ15-TT8 were higher in mutant fruit lacking pigment in pulp or peel tissues than in the wild type.Therefore,the TT8/Δ15-TT8 mRNA level ratio was found to be crucial for sufficient pigment in either pulp or peel tissues.TT8 from blood orange fruit demonstrated the capacity for nucleus localization and binding to other proteins.In contrast,Δ15-TT8,lacking the fourth exon,lost its ability to interact with RUBY1 and to localize at the nucleus.Using a dual luciferase reporter assay and transient overexpression in tobacco,we proved that two regulatory complexes formed by a functional TT8 with different MYB(v-myb avian myeloblastosis viral oncogene homolog)-type partners significantly promoted expression of an anthocyanin biosynthetic gene and a proton pumping gene,leading to anthocyanin and citrate production.Our findings suggest that TT8,rather than dysfunctionalΔ15-TT8,is possibly involved in modulating anthocyanin biosynthesis and its transport into vacuoles by proton gradients.However,increased mRNA levels of the dysfunctional alternative splicing transcript may act as a negative feedback to downregulate TT8 expression and limit anthocyanin accumulation in blood oranges.

Understanding changes in volatile compounds and fatty acids of Jincheng orange peel oil at different growth stages using GC-MS

Jincheng orange(Citrus sinensis Osbeck)is widely grown in Chongqing,China,and is commonly consumed because of its characteristic aroma contributed by the presence of diverse volatile compounds.The changes in aroma during the development and maturation of fruit are indicators for ripening and harvest time.However,the influence of growth stages on the volatile compounds in Jincheng orange remains unclear.In addition,volatiles originate from fatty acids,most of which are the precursors of volatile substances.On this basis,gas chromatography-mass spectrometry(GC-MS)was performed to elaborate the changes in volatile constituents and fatty acids as precursors.This study tested proximately 60 volatiles and 8 fatty acids at 9 growth and development stages(AF1-AF9).Of those compounds,more than 92.00%of total volatiles and 87.50%of fatty acids were terpenoid and saturated fatty acids,respectively.As shown in the PCA plot,the AF5,AF6,and AF9 stages were confirmed as completely segregated and appeared different.In addition,most of the volatiles and fatty acids first increased at the beginning of the development stage,then decreased from the AF6 development stage,and finally increased at the AF9 maturity stage.Moreover,the highest contents of terpenoid,alcohols,aldehydes,ketones,and saturated fatty acids in Jincheng orange peel oil were d-limonene,linalool,octanal,cyclohexanone,and stearic acid during development stages,respectively.Our results found that the growth stages significantly affected the volatile constituents and precursors in Jincheng orange peel oil.

CsBZIP40 confers resistance against citrus bacterial canker by repressing CsWRKY43-CsPrx53/CsSOD13 cascade mediated ROS scavenging

As the bacterial etiologic agent causing citrus bacterial canker(CBC),Xanthomonas citri subsp.citri(Xcc)seriously impacts citrus plantation and fruit production globally.In an earlier study,we demonstrated that CsBZIP40 can positively impact CBC resistance in the sweet orange(Citrus sinensis).However,the mechanistic basis for the protective benefits conferred by CsBZIP40 is yet to be delineated.Here,we show that CsBZIP40 positively regulates CBC resistance and reactive oxygen species(ROS)homeostasis in transgenic sweet orange overexpressing CsBZIP40.CsBZIP40 directly binds to the TGA-box of the CsWRKY43 promoter to repress its transcriptional activity.CsWRKY43 overexpression induces CBC susceptibility in transgenic sweet oranges.In contrast,its inhibition produces strong resistance to CBC.CsWRKY43 directly binds to the W-boxes of the CsPrx53 and CsSOD13 promoters to positively regulate the activities of these antioxidant enzymes,resulting in the negative regulation of ROS homeostasis and CBC resistance in sweet orange plants.CsPrx53/CsSOD13 knockdown enhances ROS accumulation and CBC resistance.Overall,our results outline a regulatory pathway through which CsBZIP40 transcriptionally represses CsWRKY43-CsPrx53/CsSOD13 cascade-mediated ROS scavenging in a manner conducive to CBC resistance.These mechanisms underscore the potential importance of CsBZIP40,CsWRKY43,CsPrx53,and CsSOD13,providing promising strategies for the prevention of CBC.

Generating colorful carrot germplasm through metabolic engineering of betalains pigments

Betalains are tyrosine-derived plant pigments exclusively found in the Caryophyllales order and some higher fungi and generally classified into two groups:red-violet betacyanins and yellow-orange betaxanthins.Betalains attract great scientific and economic interest because of their relatively simple biosynthesis pathway,attractive colors and health-promoting properties.Co-expressing two core genes BvCYP76AD1 and BvDODA1 with or without a glycosyltransferase gene MjcDOPA5GT allowed the engineering of carrot(an important taproot vegetable)to produce a palette of unique colors.The highest total betalains content,943.2μg·g^(−1) DW,was obtained in carrot taproot transformed with p35S:RUBY which produces all of the necessary enzymes for betalains synthesis.Root-specific production of betalains slightly relieved tyrosine consumption revealing the possible bottleneck in betalains production.Furthermore,a unique volcano-like phenotype in carrot taproot cross-section was created by vascular cambium-specific production of betalains.The betalains-fortified carrot in this study is thus anticipated to be used as functional vegetable and colorful carrot germplasm in breeding to promote health.

Appraisal of Improvement in Physiological and Metabolic Processes by Exogenously Applied Natural and Synthetic Ascorbic Acid in Okra(Abelmoschus esculentus L.)Fruit Subjected to Water Deficit Stress

To counteract the effects of drought stress,scientists have adopted several approaches including the use of different chemicals both inorganic and organic,which is contemplated as a highly efficient and cost-effective shot-gun approach.Ascorbic acid(AsA)is a potential organic substance,which widely occurs in plants,and is considered to be an effective antioxidant to counteract reactive oxygen species(ROS).Thus,a pot experiment was performed to assess the relative mitigating impacts of synthetic AsA and naturally occurring AsA in the form of lemon juice(LJ)and orange juice(OJ)on two cultivars of okra(Abelmoschus esculentus L.)namely Sabz Pari and Bhindi Sanwali under varying water deficit conditions.After 30 days of seed germination,okra seedlings were subjected to different irrigation regimes,i.e.,water deficit stress[(65%and 50%F.C.)and control conditions(100%F.C.)].Different levels of AsA[control(no spray),14 mg L^(−1)LJ,24 mg L^(−1)OJ and 150 mg L^(−1)AsA]obtained from different sources were applied as a foliar spray to control and water-stressed plants.Drought stress prominently reduced plant growth and yield attributes of the okra cultivars.Water-deficit conditions(65%and 50%F.C.)substantially decreased the fruit chlorophyll(a,b)pigments and the activity of superoxide dismutase(SOD)enzyme,while an increase was observed in the contents of fruit’s hydrogen peroxide(H_(2)O_(2)),malondialdehyde(MDA),total phenolics,total soluble sugars,AsA,and total soluble proteins.Drought stress also increased the activities of antioxidant enzymes like peroxidase(POD)and catalase(CAT).However,plant growth and yield attributes,fruit chlorophyll pigments,total phenolics,total soluble sugars,total free amino acids,total soluble proteins,AsA,GB,H_(2)O_(2),and the activities of antioxidant enzymes(POD and CAT)were increased by the AsA exogenous treatment in both okra cultivars under water deficit and control conditions.Overall,LJ and OJ were more effective than the synthetic AsA in upregulating the physiological and metabolic processes of okra plants.So,cost-effective as well as multi-nutrient natural sources of AsA could be suggested for alleviating the harmful effects of water deficit stress on plants.

Comparative Study on the Acid-Base Indicator Properties of Natural Dye, Turmeric Rhizome (Curcuma longa) and Synthetic Dyes

Acid-Base Indicator, Turmeric Rhizome (Curcuma longa) was extracted from the root of a turmeric plant. The turmeric was peeled, washed and dried in an oven at 60°C. It was ground into powder and soaked in hot and cold ethanol for the extraction. The extract was filtered and part of it was concentrated to yield a reasonable quantity of turmeric indicator. On standardization of acid with a base, 0.05 M base respectively of Sodium hydroxide (NaOH), sodium carbonate (Na2CO3) and Disodium borate (B4Na2O7) were used. Hot and cold extracts of turmeric were used as indicators and were compared with methyl orange and phenolphthalein. On the preliminary test carried out, hot and cold turmeric indicator showed yellow colour in acid medium and orange colour in the base. Methyl orange showed red colour in acid but yellow in the base, phenolphthalein was colourless in acid but pink in the base. During titration there were colour changes at the end points in the entire test carried out. The average volumes at ends points were calculated, the molar concentrations and mass concentrations of the acids used were also determined. The results showed that there was no difference between the natural indicators used and the existing synthetic indicators which are toxic to our environment.

Use of Agent Purple, Agent Orange and Agent Blue on Royal Thai Air Force Base Perimeters in Thailand during the Vietnam War

Seven Royal Thai Air Force bases in Thailand were used by the United States Air Force (USAF) during the Vietnam War as staging hubs for operations in Laos and Cambodia. Five bases in Thailand, including Nakhon Phanom (NKP), Ubon, Korat, U-Tapao and Udorn endured sniper fire interdiction, perimeter penetration, and sapper (combat engineer) attacks. Nam Phong, an eighth Royal Thai Air Force base was used by the United States Marine Corps air operations starting in 1972. US Military personnel stationed throughout Thailand were also attacked by Communists insurgents. Two herbicides, Agent Purple and Agent Orange containing 2, 4, 5-T contaminated with dioxin (TCDD—2, 3, 7, 8 tetrachlorodibenzodioxin) and a third herbicide, the arsenic-based Agent Blue, were routinely received at these Thailand airbases in support of air missions and to keep airbases and perimeter fences clear of vegetation. Udorn Royal Thai Air Force (RTAF) base, established in the 1950s was consistently a target of enemy attacks during this period. The Thai government allowed the United States to use five bases, covertly, and two other Thai bases, openly, due to concerns that the civil war inside Laos might spread into Thailand. The US Air Force began, in 1961, to provide the air defense of Thailand and to fly reconnaissance flights over Laos. Under the United States and Thailand’s “gentleman’s agreement”, the bases used by the USAF were considered RTAF bases under the command of Thai officers. The USAF at Udorn was under the command of the United States Pacific Air Forces (PACAF) Thirteenth Air Force and was used to temporarily store and distribute Agent Purple, Agent Orange and Agent Blue to Laos’s airfields for spraying of the Ho Chi Minh Trail. Thai air police controlled access to the bases using sentry dogs, observation towers, and machine gun emplacements. The USAF Security police assisted the Thai air police in base defense. In this study, we document the use of Agent Orange, Agent Purple and Agent Blue on Royal Thai Air Force base perimeters and grounds during the Vietnam War, potential active-duty service personnel exposure to these toxic herbicides and health impacts of the contaminant dioxin TCDD and arsenic on U.S. Vietnam Era Veterans and Vietnam Veterans. This documentation is important evidence in the “assumption of exposure” for health claims to the US Veterans Administration (VA) by veterans that served in Thailand between 1962 and 1976.