EVALUATION OF TWO NESTED PCR-BASED DIAGNOSTIC ASSAYS FOR PLASMODIUM FALCIPARUM INFECTION

  Objective: The majority of malaria cases and deaths are caused by Plasmodium falciparum. The rapid and accurate diagnosis is very important for malaria treatment and control. The aim of this study was to evaluate two nested polymerase chain reaction (PCR)-based methods (protocol A and protocol B) for P. falciparum infection, diagnosis in Thailand.Methods: A total of 90 dried blood spot samples were investigated. The samples composed of P. falciparum-, Plasmodium vivax-infected blood and normal human blood samples. The microscopic examination was used as gold standard.Results: The results showed the sensitivity of 100/83.33%, specificity of 100/100%, and accuracy of 100/94.44% for protocol A and protocol B, respectively. The analytical sensitivity of protocol A and protocol B was 0.625 and 6.25 parasites/μl, respectively. The comparison among microscopic examination, protocol A and protocol B by statistical analysis, found that they were not a significant difference. The agreements between each method were good. The kappa value between protocol A and protocol B was 0.87, protocol A and microscopy was 1.00, and protocol B and microscopy was 0.87.Conclusion: The results demonstrated that protocol A should be used for further development of P. falciparum diagnosis in Thailand, especially in case of low parasitemia such as asymptomatic infection and for screening blood donors

Simultaneous detection of ammonium and nitrate in environmental samples using on ion-selective electrode and comparison with portable colorimetric assays

Simple, robust, and low-cost nitrate-and ammonium-selective electrodes were made using substrate prepared from household materials. We explored phosphonium-based ILs and poly (methyl methacrylate)/poly(decyl methacrylate)(MMA-DMA) copolymer as matrix materials alternative to classical PVC-based membranes. IL-based membranes showed suitability only for nitrate-selective electrode exhibiting linear concentration range between 5.0 × 10−6 and 2.5 × 10−3 M with a detection limit of 5.5 × 10−7 M. On the other hand, MMA-DMA—based membranes showed suitability for both ammonium-and nitrate-selective electrodes, and were successfully applied to detect NO3− and NH4+ in water and soil samples. The proposed ISEs exhibited near-Nernstian potentiometric responses to NO3− and NH4+ with the linear range concentration between 5.0 × 10−5 and 5.0 × 10−2 M (LOD = 11.3 µM) and 5.0 × 10−6 and 1.0 × 10−3 M (LOD = 1.2 µM), respectively. The power of ISEs to detect NO3− and NH4+ in water and soils was tested by comparison with traditional, portable colorimetric techniques. Procedures required for analysis by each technique from the perspective of a non-trained person (e.g., farmer) and the convenience of the use on the field are compared and contrasted

Simultaneous detection of ammonium and nitrate in environmental samples using on ion-selective electrode and comparison with portable colorimetric assays

Simple, robust, and low-cost nitrate-and ammonium-selective electrodes were made using substrate prepared from household materials. We explored phosphonium-based ILs and poly (methyl methacrylate)/poly(decyl methacrylate)(MMA-DMA) copolymer as matrix materials alternative to classical PVC-based membranes. IL-based membranes showed suitability only for nitrate-selective electrode exhibiting linear concentration range between 5.0 × 10−6 and 2.5 × 10−3 M with a detection limit of 5.5 × 10−7 M. On the other hand, MMA-DMA—based membranes showed suitability for both ammonium-and nitrate-selective electrodes, and were successfully applied to detect NO3− and NH4+ in water and soil samples. The proposed ISEs exhibited near-Nernstian potentiometric responses to NO3− and NH4+ with the linear range concentration between 5.0 × 10−5 and 5.0 × 10−2 M (LOD = 11.3 µM) and 5.0 × 10−6 and 1.0 × 10−3 M (LOD = 1.2 µM), respectively. The power of ISEs to detect NO3− and NH4+ in water and soils was tested by comparison with traditional, portable colorimetric techniques. Procedures required for analysis by each technique from the perspective of a non-trained person (e.g., farmer) and the convenience of the use on the field are compared and contrasted

Transforming state tables to coloured petri nets for automatic verification of internet protocols

Gordon, SD ORCiD: 0000-0003-4090-1199Rapid developments in networking technologies is resulting in an increasing number of new communication protocols being created, but formal methods are seldom used to verify their design. This paper presents a set of rules for transforming state tables, a common format of protocol specifications in standards, into a formal model based on Coloured Petri nets. This reduces time for developing and debugging CPN models, which can then be used for protocol verification. Formal definitions of subsets of state tables and CPNs are presented, as well as the transformation algorithm. To demonstrate the transformation an example of Stop-and-Wait protocol is used as a case study

Transforming state tables to coloured petri nets for automatic verification of internet protocols

Rapid developments in networking technologies is resulting in an increasing number of new communication protocols being created, but formal methods are seldom used to verify their design. This paper presents a set of rules for transforming state tables, a common format of protocol specifications in standards, into a formal model based on Coloured Petri nets. This reduces time for developing and debugging CPN models, which can then be used for protocol verification. Formal definitions of subsets of state tables and CPNs are presented, as well as the transformation algorithm. To demonstrate the transformation an example of Stop-and-Wait protocol is used as a case study

Bio-Electroanalysis Performance of Heme Redox-Center for <i>π</i>-<i>π</i> Interaction Bonding of a Methylene Blue-Graphene Modified Electrode

Hemeprotein detection has motivated extensive research on the direct reaction of a heme molecule and a redox dye. The present study used methylene blue as both donor and acceptor for a redox reaction. First, the solid phases of methylene blue (MB) and graphene (GP) formed a π-π interaction bond at the aromatic rings. The conductivity of GP was better than that of carbon in a carbon electrode (CE). Then, the working CE was modified using strong adsorption of MB/GP on the electrode surface. The surface of the electrode was investigated using a modified and an unmodified electrode. The electrode’s properties were studied using voltammograms of redox couple K3[Fe(CN)6]3−/4−. Its reaction was used to find the active area of the modified electrode, which was 1.76 times bigger than that of the unmodified electrode. The surface coverage values of the modified and unmodified electrodes were 8.17 × 10−6 and 1.53 × 10−5 mol/cm2, respectively. This research also studied the application of hemeprotein detection. Hemoglobin (Hb), myoglobin (Mb), and cytochrome c (Cyt. C) were studied by the reaction of Fe (III/II) at the heme-redox center. The electrocatalytic reaction between MB/GP and hemeproteins produced an anodic peak at 0.35 V for Hb, Mb, and Cyt. C. This nanohybrid film enhanced electron transfer between protein molecules and the modified carbon electrode. The amperometric measurements show that the limit of detection was 0.2 µM, 0.3 µM, and 0.1 µM for Hb, Mb, and Cyt. C, respectively. The measurement spanned a linear range of 0.2 µM to 5 µM, 0.3 µM to 5 µM, and 0.1 µM to 0.7 µM for Hb, Mb, and Cyt. C, respectively. Hb showed the lowest sensitivity compared with Mb and Cyt. C due to the role of steric hindrance in the hemeprotein specificity structure. This study offers a simple and efficient fabrication platform for electrochemical sensors for hemeproteins. When compared to other complex immobilization processes, the fabrication method for this sensor has many benefits, including no need for special chemicals and easy preparation and electrode modification—both of which are crucial for the development of electrochemical sensing devices

Screening a small library of xanthones for antitumor activity and identification of a hit compound which induces apoptosis

Our previous work has described a library of thioxanthones designed to have dual activity as P-glycoprotein modulators and antitumor agents. Some of these compounds had shown a significant cell growth inhibitory activity towards leukemia cell lines, without affecting the growth of non-tumor human fibroblasts. However, their effect in cell lines derived from solid tumors has not been previously studied. The present work aimed at: (i) screening this small series of compounds from an in-house library, for their in vitro cell growth inhibitory activity in human tumor cell lines derived from solid tumors; and (ii) initiate a study of the effect of the most potent compound on apoptosis. The tumor cell growth inhibitory effect of 27 compounds was first analysed in different human tumor cell lines, allowing the identification of a hit compound, TXA1. Its hydrochloride salt TXA1 HCl was then synthesized, to improve solubility and bioavailability. Both TXA1 and TXA1 HCl inhibited the growth of MCF-7, NCI-H460, A375-C5, HeLa, 786-O, Caki-2 and AGS cell lines. The effect of TXA1 HCl in MCF-7 cells was found to be irreversible and was associated, at least in part, with an increase in cellular apoptosis.IPATIMUP integrates the i3S Research Unit, which is partially supported by FCT, the Portuguese Foundation for Science and Technology. This work is funded by FEDER funds through the Operational Programme for Competitiveness Factors-COMPETE and National Funds through the FCT-Foundation for Science and Technology, under the projects FEDER COMPETE FCOMP-01-0124-FEDER-015752, FCOMP-01-0124-FEDER-011057, NORTE-07-0162-FEDER-00018—“Contributos para o reforço da capacidade do IPATIMUP enquanto actor do sistema regional de inovação” and NORTE-07-0162-FEDER-000067—“Reforço e consolidação da capacidade infraestrutural do IPATIMUP para o sistema regional de inovação”, both supported by Programa Operacional Regional do Norte (ON.2—O Novo Norte), through FEDER funds under the Quadro de Referência Estratégico Nacional (QREN). This research was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT—Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the programme PT2020. The authors also thank FCT for the grant of R.T. Lima (SFRH/BPD/68787/2010) and QREN for the grant of D. Sousa (NORTE-07-0124-FEDER-000023)